n
C7^-
F/3
to give to
of public
arther, the
and an an-
ig money,
mankind,
^ a bro-
, and
>e ye
i not.
doth
1 in
pter
,t a
it is
ry
tShr.rity.
C H A [ 401 ] C H A
proved. Some may perifti by fucb a conduft. Men
are fometimes overtaken by diltrefs, for which all
other relief would come too late. Befides which, re-
folutions of this kind compel us to offer fuch violence
to our humanity, as may go near, in a little while, to
fuffocate the principle itfelf; which is a very ferious
confideration. A good man, if he do not furrender
himfelf to his feelings without referve, will at leaft lend
an ear to importunities which come accompanied with
outward attellations of diflrefs; and after a patient
hearing of the complaint, will direft himfelf by the
circumrtances and credibility of the account that he
receives.
There are other fpecies of charity well contrived to
make the money expended go far; fuch as keeping
down the price of fuel or provifions in cafe of a mono¬
poly or temporary fcarcity, by purchafing the articles
at the beft market, and retailing them at prime coll,
or at a fmall lofs •, or the adding a bounty to a parti¬
cular fpecies of labour, when the price is, accidentally
deprelfed.
The proprietors of large eftates have it in their
power to facilitate the maintenance, and thereby en¬
courage the eftablifhment of families (which is one of
the nobleft purpofes to which the rich and great can
convert their endeavours), by building cottages, fplit-
ting farms, erefting manufaflures, cultivating waftes,
embanking the fea, draining marfhes, and other expe¬
dients, which the fituation of each eltate points out.
If the profits of thefe undertakings do not repay the
expence, let the authors of them place the difference
to the account of charity. It is true of almoft all
fuch proje£ls, that the public is a gainer by them,
whatever the owner be. And where the lofs can be
fpared, this confideration is fufficient.
It is become a queftion of fome importance, Under
what circumftances wmrks of charity ought to be done
in private, and when they may be made public with¬
out detracting from the merit of the aftion ? if indeed
they ever may, the Author of our religion having de¬
livered a rule upon this fubjeCl, which feems to enjoin
univerfal fecrecy. ‘‘When thou doell alms, let not
thy left hand know what thy right hand doth 5 that
thy alms may be in fecret: and thy Father which feeth
in fecret, himfelf lhall reward thee openly.” (Matth.
vi. 3, 4.) From the preamble to this prohibition, it
is plain, that our Saviour’s foie defign was to forbid
ojlentation, and all publifhing of good works which pro¬
ceeds from that motive. “ Take heed that ye do not
your alms before men, to befeen of them ; otherwife ye
have no reward of your Father, which is in heaven ;
therefore, when thou doefl thine alms, do not found a
trumpet before thee, as the hypocrites do, in the fy-
nagogues and in the ftreets, that they may have glory
of men. Verily I fay unto thee, they have their re¬
ward,” v. 2. There are motives for the doing our
alms in public befides thofe of oftentation 5 with w'hich
therefore our Saviour’s rule has no concern : fuch as
to teftify our approbation of fome particular fpecies of
charity, and to recommend it to others •, to take off
the prejudice wrhich the want, or, which is the fame
thing, the fuppreftion, of our name in the lift of con¬
tributors, might excite againft the charity or againft
curfelves. And fo long as thefe motives are free from
any mixture of vanitv, they are in no danger of invad-
Vox,. V. Part. XL '
ing our Saviour’s prohibition : they rather feem to
comply with another direftion which he has left us :
“ Let your light fo fliine before men, that they may
fee your good works, and glorify your Father wdiich
is in heaven.” If it be neceffary to propofe a precife
diftinClion upon the fubjeft, there can be none better
than the following : When our bounty is beyond our
fortune or ftation, that is, when it is more than could
be expeCled from us, our charity ftrould be private, if
privacy be prafticable : when it is not more than
might be expedited, it may be public : for wTe cannot
hope to influence others to the imitation of extraordi-
nary generofity, and therefore wrant, in the former
cafe, the only juftifiable reafon for making it public.
The pretences by which men excufe themfelves from
giving to the poor are various j as,
1. “ That they have nothing to fpare i, e. no¬
thing, for which they have not fome other ufe ; no¬
thing, which their plan of expence, together with the
favings they have refolved to lay by, will not exhauft ;
never refleifling whether it be in their power, or that
it is their duty, to retrench their expences, and con-
tra£l their plan, “ that they may have to give to them
that need or rather that this ought to have been
part of their plan originally.
2. “ That they have families of their own, and that
charity begins at home.” A father is no doubt bound
to adjuft his economy with a view to the reafonable de¬
mands of his family upon his fortune ; and until a fuf-
ficiency for thefe is acquired, or in due time probably
will be acquired (for in human affairs probability is
enough, he is juftified in declining expenjive liberality j
for to take from thofe who want, in order to give to
thofe who want, adds nothing to the flock of public
happinefs. Thus far, therefore, and no farther, the
plea in queftion is an excufe for parfimony, and an an-
fw’er to thofe wrho folicit our bounty.
3. “ That charity does not confift in giving money,
but in benevolence, philanthropy, love to all mankind,
goodnefs of heart,” &c. Hear St James. “ If a bro¬
ther or After be naked, and deftitute of daily food, and
one of you fay unto them, depart in peace, be ye
warmed and filled, notwithftanding ye give them not
thofe things which are needful for the body, what doth
it profit ?” (James ii. 15, 16.)
4. “ That giving to the poor is not mentioned in
St Paul’s defeription of charity, in the 13th chapter
of his firft epiftle to the Corinthians.” This is not a
defeription of charity, but of good nature ; and it is
not neceffary that every duty be mentioned in every
place.
5. “ That they pay the poor rates.” They might
as well allege that they pay their debts ; for the poor
have the fame right to that portion of a man’s property
which the laws affign them, that the man himfelf has
to the remainder.
6. “ That they employ many poor perfons —for
their own fake, not the poor’s—otherwife it is a good
plea.
Cfcarity.
7. “ That the poor do not fuffer fo much as w e
imagine •, that education and habit have reconciled
them to the evils of their condition, and make them
eafy under it.” Habit can never reconcile human na¬
ture to the extremities of cold, hunger, and thirft,
any more than it can reconcile the hand to the touch
3 E of
C H A
[ 4°2 1
C H A
Charity, of a red-hot Iron : befides the queftion is not, how un-
 v happy any one is, but how much more happy we can
make him ?
8. “ That thefe people, give them what you will,
will never thank you, or think of you for it.” In the
firft place, this is not true : in the fecond place, it
was not for the fake of their thanks that you relieved
them.
9. “ That we are fo liable to be impofed upon.” If
a due inquiry be made, our motive and merit is the
fame : befide that the diftrefs is generally real, what¬
ever has been the caufe of it.
10. “ That they ihould apply to their pariihes.”
This is not always practicable : to which we may add,
that there are many requifites to a comfortable fub-
liftence, which parifti-relief does not always fupply j
and that there are fome who w'ould fuffer almoft as
much from receiving parifh-relief as by the want of it;
and laftly, that there are many modes of charity, to
which this anfwer does not relate at all.
11. “ That giving money encourages idlenefs and
vagrancy.” This is true only of injudicious and indif-
criminate generofity.
12. “ That we have too many objeCls of charity at
home to beftow any thing upon ftrangers } or that
there are other charities wThich are more ufeful, or ftand
in greater need.” The value of this excufe depends
entirely upon the fa&, whether we aClually relieve thofe
neighbouring objeCls, and contribute to thofe other
charities.
Befides all thefe excufes, pride, or prudery, or
delicacy, or love of eafe, keep one half of the world
out of the way of obferving what the other half
fuffer.
Chjritt Schools, are fchools ereCled and maintain¬
ed in various parifhes by the voluntary contributions of
the inhabitants, for teaching poor children to read,
write, and other neceffary parts of education. See
School.
Brothers of Charity, a fort of religious hofpitallers,
founded about the year 1297, fince denominated Bil-
letins. They took the third order of St Francis, and
the fcapulary, making the three ufual vows, but with¬
out begging.
Brothers of Charity, alfo denote an order of hofpi¬
tallers, ftill fubfifting in Romilh countries, whofe bufi-
nefs is to attend the fick poor, and minifier to them
both fpiritual and temporal fuccour.
They are all laymen, except a few priefts, for ad-
miniftering the facraments to the fick in their hofpi-
tals. The brothers of charity ufually cultivate bota¬
ny, pharmacy, furgery, and chemiftry, which they
praftife with fuccefs.
They were firft founded at Granada, by St John de
Dieu ; and a fecond eftablifhment was made at Madrid
in the year 15 ^3 : the order was confirmed by Grego¬
ry XIII. in 1572: Gregory XIV. forbade them to take
holy orders; but by leave of Paul V. in 1609, a few
of the brothers might be admitted to orders. In 1619
they were exempted from the jurifdiftion of the biftiop.
Thofe of Spain are feparated from the reft ; and they,
as well as the brothers of France, Germany, Poland
and Italy, have their diftinft generals, who refide at
Rome. They were firft introduced into France by Mary
Charles.
of Medicis in 1601, and have fince built a fine hofpital Charity
in the Fauxbourg St Germain.
Charity of St Hippolitus, a religious congregation,
founded about the end of the 14th century, by one Ber-
nardin Alvarez, a Mexican, in honour of St Plippolitus
the martyr, patron of the city of Mexico ; and ap¬
proved by Pope Gregory XIII.
Charity of our Lady, in church hiftory, a religious
order in France, which, though charity was the princi¬
pal motive of their union, grew in length of time fo
diforderly and irregular, that their order dwindled, and
at laft became extinft.
There is ftill at Paris, a religious order of women,
called nuns hofpitallers of the charity of our lady. The
religious of this hofpital are by vow obliged to admi-
nirter to the neceflxties of the poor and the fick, but
thofe only women.
CHARLATAN, or Charletan, fignifies an em- .
piric or quack, who retails his medicines on a public
flage, and draws people about him with his buffoone¬
ries, feats of adlivity, &c. The word, according to
Calepine, comes from the Italian, ceretano; of Caretumt
a town near Spoletto in Italy, where thefe impoftors
are faid to have firft rifen. Menage derives it from
ciarlatano, and that from circulatorius, of circulator, a
quack.
CHARLEMAGNE, or Charles I. king of France
by fucceflion, and emperor of the weft by conqueft in
800 (which laid the foundation of the dynafty of the
weftern Franks, who ruled the empire 472 years till
the time of Rodolphus Aufpurgenfis, the founder of
the houfe of Auftria). Charlemagne was as illuftrious
in the cabinet as in the field ; and, though he could
not write his name, was the patron of men of letters,
the reftorer of learning, and a wife legifiator ; he want¬
ed only the virtue of humanity to render him the moft
accompliftied of men; but when we read of his behead¬
ing 4500 Saxons, folely for their loyalty to their prince,
in oppofing his conquefts, we cannot think he merits
the extravagant encomiums beftow'ed on him by fome
hiftorians. He died in 814, in the 74th year of his
age, and 47th of his reign.
^ France had nine fovereigns of this name, of whom
Charles V. merited the title of the wife, (crowned in
1364 died in 1380) : and Charles VIII. fignalized
himfelf in the field by rapid viflories in Italy ; (crown¬
ed in 1483, died in 1498.) The reft do not deferve
particular mention in this place. See (Hijlory of)
France.
CHARLEMONT, a town of the province of
Namur in the Auftrian Netherlands, about 18
miles fouth of Namur. E. Long. 4. 40. N. Lat.
50. 10.
Charlemont is alfo the name of a town of Ire¬
land, fituated on the river Blackwater, in the county
of Armagh, and province of Ulfter, about fix miles
fouth-eaft of Dungannon. W. Long. 6. 50. N. Lat.
50. 16.
CHARLEROY, a ftrong town in the province of
Namur in the Auftrian Netherlands, fituated on the ri¬
ver Sambre, about 19 miles weft of Namur. E. Long.
4. 20. N. Lat. 50. 30.
CHARLES Martel, a renowmed conqueror in
the early annals of France. He depofed and reftored
Childeric
C H A [ 403 ] C H A
Charles. Childeric Idng of France j and had the entire govern-
ment of the kingdom, once with the title of mayor of
the palace, and afterwards as duke of France; but he
would not accept the crown. He died regretted, in
741.
Charles le Gros, emperor of the weft in 88 r, king of
Italy and Suabia, memorable for his reverfe of fortune j
being dethroned at a diet held near Mentz, by the
French, the Italians, and the Germans, in 887 : after
which he was obliged to fubfift on the bounty of the
archbilhop of Mentz. He died in 888.
Charles V. (emperor and king of Spain), was fon
of Philip I. archduke of Auftria and of Jane qu£en of
Caftile. He was born at Ghent, February 24. 1500.
and fucceeded to the crown of Spain in 1517. Two
years afterwards he was chofen emperor at Francfort
after the death of Maximilian his grandfather. He
was a great warrior and politician : and his ambition
was not fatisfied with the many kingdoms and pro¬
vinces he poffeffed j for he is fuppofed, with reafon, to
have afpired at univerfal empire. He is faid to have
fought 60 battles, in moft of which he was viftorious.
He took the king of France (Francis I.) prifoner, and
fold him his liberty on very hard terms yet after¬
wards, when the people of Ghent revolted, he alked
leave to pafs through his dominions : and though the
generous king thus had him in his power, and had an
opportunity of revenging his ill treatment, yet he re¬
ceived and attended him with all pomp and mag¬
nificence. He facked Rome, and took the pope pri¬
foner $ and the cruelties which his army exercifed
there are faid to have exceeded thofe of the northern
barbarians. Yet the pious emperor went into mourn¬
ing on account of this conqueft : forbade the ringing of
bells ; commanded proceflions to be made, and prayers
to be offered up for the deliverance of the pope his
prifoner j yet did not inflift the leaft punilhment on
thofe who treated the holy father and the holy fee with
fuch inhumanity. He is accufed by fome Romilh writ¬
ers of favouring the Lutheran principles, which he
might eafily have extirpated. But the truth is, he found
bis account in the divifions which that fedf occafioned $
and he forever made his advantage of them, fometimes
againft the pope, fometimes againft France, and at
other times againft the empire itfelf. He was a great
traveller, and made 50 different journeys into Germany,
Spain, Italy, Flanders, France, England, and Africa.
Though he had been fuccefsful in many unjuft enter-
prifes, yet his laft: attempt on Metz, which he befieged
with an army of 100,000 men, was very juft, and very
unfuccefsful.
Vexed at the reverfe of fortune which feemed to
attend his latter days, and oppreffed by ficknefs, which
unfitted him any longer for holding the reins of go¬
vernment with fteadinefs, or to guide them wdth ad-
drefs, he refigned his dominions to his brother
Ferdinand and his fon Philip 5 and retreated to the
monaftery of St Juftus near Placentia in Eftrema-
dura.
When Charles entered this retreat, he formed fuch
a plan of life for himfelf as would have fuited a pri¬
vate gentleman of moderate fortune. His table was
neat, but plain *, his domeftics few ; his intercourfe
with them familiar ; all the cumberfome and ceremo¬
nious forms of attendance on his perfon were entirely
abolifhed, as deftruffive of that focial eafe and tran- Char'«.
quillity which he courted in order to foothe the remain- ‘■“■"V”"’”
der of his days. As the mildnefs of the climate, toge¬
ther with his deliverance from the burdens and cares
of government, procured him at firft a confiderable
remiflion from the acute pains of the gout, with which
he had been long tormented, he enjoyed perhaps more
complete fatisfadion in this humble folitude than all
his grandeur had ever yielded him. The ambitious
thoughts and projefts which had fo long engroffed and
difquieted him were quite effaced from his mind. Far
from taking any part in the political tranfadions of
the princes of Europe, he reftrained his curiofity even
from an inquiry concerning them ; and he feemed to
view the buiy fcene which he had abandoned with
all the contempt and indifference arifing from his
thorough experience of its vanity, as well as from the
pleafing refledion of having difentangled himfelf from
its cares.
Other amufements, and other fubjeds, now occupied
him. Sometimes he cultivated the plants in his gar¬
den with his own hand $ lometimes he rode out to
the neighbouring wood on a little horfe, the only one
that he kept, attended by a Angle fervant on foot.
When his infirmities confined him to his apartment,
which often happened, and deprived him of thele more
adive recreations, he either admitted a tew gentlemen
who refided near the monaftery to vifit him, and en¬
tertained them familiarly at his table *, or he employed
himfelf in ftudying mechanical principles, and in form¬
ing curious works of mechanifm, of which he had al¬
ways been remarkably fond, and to which his genius
was peculiarly turned. With this view he had enga¬
ged Turriano, one of the moft ingenious artifts of that
age, to accompany him in his retreat. He laboured
together with him in framing models of the moft ufe-
ful machines, as wTell as in making experiments with
regard to their refpedive powers ; and it was not fel-
dom that the ideas of the monarch aflifted or perfeded
the inventions of the artift. He relieved his mind at
intervals with flighter and more fantaftic works of me¬
chanifm, in fafhioning puppets, which, by the ftrudure
of internal fprings, mimicked the geftures and adions
of men, to the no fmall aftoniftiment of the ignorant
monks, who, beholding movements which they could
not comprehend, fometimes diftrufted their own fenfes,
and fometimes fufpeded Charles and Turriano of be¬
ing in compad with invifible powers. He was parti¬
cularly curious with regard to the conftrudion of clocks
and watches $ and haviiig found, after repeated trials,
that he could not bring any two of them to go exadly
alike, he refleded, it is faid, with a mixture of fur-
prife as well as regret, on his own folly, in having be-
ftow'ed fo much time and labour in the more vain at¬
tempt of bringing mankind to a precife uniformity of
fentiment concerning the intricate and myfterious doc¬
trines of religion.
But in what manner foever Charles difpofed of the
reft of his time, he conftantly referved a confiderable
portion of it for religious exercifes. He regularly at¬
tended divine fervice in the chapel of the monaftery,
every morning and evening j he took great pleaiure
in reading books of devotion, particularly the works
of St Auguftine and St Bernard ; and converfed much
with his confeffor, and the prior of the monaftery,
3 E 2 on
C H A
Charles, on pious fubjecls. Thus did Charles pafs
 year of his retreat in a manner not unbecoming a
man perfeflly difengaged from the affairs of this pre-
fent life, and Handing on the confines of a future
world, either in innocent amufements which foothed
his pains, and relieved a mind worn out with excel-
iive application to bufmefs •, or in devout occupations,
which he deemed neceffaryin preparing for another ftate.
But, about fix months before his death, the gout,
after a longer intermiflion than ufual, returned with
a proportional increafe of violence. His fhattered con-
ffitution had not ftrength enough remaining to with-
ftand Rich a {hock. It enfeebled his mind as much as
his body 5 and from this period we hardly difcern any
traces of that found and mafculine underftanding which
diftinguiftied Charles among his cotemporaries. An
illiberal and timid fuperftition depreffed his fpirit. He
had no relifh for amufements of any kind. He endea¬
voured to conform, in his manner of living, to all the
rigour of monaftic aufterity. He defired no other
fociety than that of monks, and was almoft continu¬
ally employed in chanting with them the hymns of the
miffal. As an expiation for his fins, he gave himfelf
the ditcipline in fecret, with fuch feverity, that the
whip of cords which he employed as the inftrument of
his punifhment, was found, after his deceafe, tinged
with his blood. Nor w7as he fatisfied with thefe a£ls
of mortification, which, however fevere, were not
unexampled. T he timorous and diftruftful folicitude
which ahvays accompanies fuperftition, ftill continu¬
ed to difquiet him, and depreciating all that he had
done, prompted him to aim at fomething extraordina¬
ry, at fome new and fingular aft of piety, that would
difplay his zeal, and merit the favour of heaven.
The aft on wdiich he fixed was as wild and uncom¬
mon as any that fuperftition ever fuggefted to a dif-
ordered fancy. He refolved to celebrate his owrn ob-
fequies before his death. He ordered his tomb to be
erefted in the chapel of the monaftery. His domef-
tics marched thither in funeral proceffion, with black
tapers in their hands. He himfelf followed in his
fhroud. He was laid in his coffin with much folem-
nity. The fervice for the dead was chanted ; and
Charles joined in the prayers which were offered up
for the reft of his foul, mingling his tears with thofe
which his attendants filed, as if they had been cele¬
brating a real funeral. The ceremony clofed with
fprinkling holy water on the coffin in the ufual form,
and, all the affiftants retiring, the doors of the chapel
were (hut. Then Charles rofe out of the coffin, and
withdrew to his apartment, full of thofe awful fenti-
ments which fuch a fingular folemnity was calculated
to infpire. But either the fatiguing length of the ce¬
remony, or the impreffion which this image of death
left on his mind, affefted him fo much, that next day
he was feized with a fever. His feeble frame could
not long refift its violence •, and he expired on the
21 ft of September, after a life of 58 years 6 months
and 21 days.
Charles I. 1 Kings of Britain. See Britain,
Charles II. 3 N° 49 254.
Charles Xli. king of Sweden was born in 1682.
By his father’s wall, the adminiftration was lodged in
the hands of the queen dowager Eleonora, with five
lenators, till the young prince was 18 : but he was
[ 404 ] c H A
the firft declared major at 15, by the ftates convened at Stock¬
holm. The beginning of his adminiftration raifed no
favourable ideas of him, as he was thought both by
Swedes and foreigners to be a perion of mean capaci¬
ty. But the difficulties that gathered round him, foon
afforded him an opportunity to difplay his real charac¬
ter. Three powerful princes, Frederick king of Den¬
mark, Auguftus king of Poland and eleftor of Saxony,
and Peter the Great czar of Mufcovy, prefuming on
his youth, confpired his ruin almoft at the fame in-
ftant. Their meafures alarming the council, they
w'ere for diverting the ftorm by negotiations} but
Charles, with a grave refolution that altonifhed them,
faid, “ I am refolved never to enter upon an unjuit
war, nor to put an end to a juft one but by the
deftruftion of my enemies. My refolution is fix¬
ed : I will attack the firft who ihall declare againft
me j and when I have conquered him, I may hope
to ftrike a terror into the reft.” The old counfel-
lors received his orders with admiration •, and were
ftill more furprifed when they faw him on a hidden
renounce all the enjoyments of a court, reduce his
table to the utinoft frugality, drefs like a common fol-
dier, and, full of the ideas of Alexander and Caffar,
propofe thefe twTo conquerors for his models in every
thing but their vices. The king of Denmark began
by ravaging the territories of the duke of Holftein,
Upon this Charles carried the war into the heart of
Denmark, and made fuch a progrefs that the king of
Denmark thought it beft to accept of peace, which
wTas concluded in 1700. He next refolved to ad¬
vance againft the king of Poland, wffio had blocked up
Riga. He had no fooner given orders for his troops
to go into winter quarters, than he received advice
that Narva, where Count Horne was governor, was
befieged by an army of 100,000 Mufcovites. This
made him alter his meafures, and move toward the
czar ; and at Narva he gained a furprifing viftory,
which coft him not above 2000 men killed and wound¬
ed. The Mufcovites were forced to retire from the
provinces they had invaded. He puriued his con-
queits, till he penetrated as far as wffiere the diet of.
Poland was fitting •, when he made them declare the
throne of Poland vacant, and eleft Staniflaus their
king : then making himfelf mafter of Saxony, he ob¬
liged Auguftus himfelf to renounce the crown of Po¬
land, and acknowledge Staniftaus by a letter of con¬
gratulation on his acceffion. All Europe was furprif¬
ed with the expeditious finifiling of this great negotia¬
tion, but more at the difintereftednefs of the king of
Sweden, who fatisfied himfelf with the bare reputa¬
tion of this viftory, without demanding an inch of
ground for enlarging his dominions. After thus re¬
ducing the king of Denmark to peace, placing a new
king on the throne of Poland, having humbled the
emperor of Germany, and protefted the Lutheran re¬
ligion, Charles prepared to penetrate into Mufcovy,
in order to dethrone the czar. He quickly obliged
the Mufcovites to abandon Poland, purfued them into
their own country, and won feveral battles over them.
The czar, difpofed to peace, ventured to make fome
propofals j Charles only anfwered, “ I will treat with
the czar at MofcowT’ When this haughty anfwes
was brought to Peter, he faid, “ My brother Charles
ftill affefts to aft the Alexander, but I flatter my.
felt
Charles.
C H A
Charles, felf lie 'will not in me find a Darius.” The event
—'Y”—'' juftified him : for the Mufcovites, already beaten into
difcipline, and under a prince of fuch talents as Peter,
entirely deftroyed the Swedifh army at the memorable
battle of Pultowa, July 8. 1709; on which decifive
day, Charles loft the fruits of nine years labour, and
of almoft 100 battles ! The king, with a fmall troop,
purfued by the Mufcovites, paffed the Borifthenes
to Oczakow in the Turkifh territories : and from
thence, through defert countries, arrived at Ben¬
der; where the fultan, when informed of his arrival,
fent orders for accommodating him in the beft man¬
ner, and appointed him a guard. Near Bender Charles
built a. houfc, and intrenched himfelf; and had with
him l8bo men, who were all clothed and fed, with
their horfes, at the expence of the grand fignior.
* Here he formed a defign of turning the Ottoman
arms upon his enemies ; and is faid to have had a pro-
mife from the vizir of being fent into Mufcovy with
200,000 men. While he remained here, he infenfibly
acquired a tafte for books: he read the tragedies of
Corneille and Racine, with the works of Defpreaux,
whofe fatires he relifhed, but did not much admire his
other works. When he read that paffage in which
the author reprefents Alexander as a fool and a mad¬
man, he tore out the leaf. He would fometimes play
at chefs : but when he recovered of his wounds, he re¬
newed his fatigues in exercifing his men ; he tired
three horfes a-day ; and thofe who courted his favour
were all day in their boots. To difpofe the Ottoman
Porte to this war, he detached about 800 Poles and
Coffacks of his retinue, with orders to pafs the
Niefter, that runs by Bender, and to obferve what
paffed on the frontiers of Poland. The Mufcovite
troops, difperfed in thofe quarters, fell immediately
upon this little company, and purfued them even to
the territories of the grand fignior. This was what
the king expe&ed. His irfinifters at the Porte ex¬
cited the Turks to vengeance ; but the czar’s money
removed all difficulties, and Charles found himfelf in
a manner prifoner among the Tartars. He imagined
the fultan was ignorant of the intrigues of his grand
vizir. Poniatowfky undertook to make his complaints
to the grand fignior. The fultan, in anfwer, fome
days after, fent Charles five Arabian horfes, one of
which was covered with a faddle and houfing of great
richnefs ; with an obliging letter, but conceived in fuch
general terms, as gave reafon to fufpeift that the mi-
nifter had done nothing without the fultan’s content :
Charles therefore refufed them. Poniatowfky had the
courage to form a defign of depofing the grand vizir,
who accordingly was deprived of his dignity and
wealth, and banifhed. The feal of the empire tvas
given to Numan Cuproughly ; who perfuaded his ma¬
iler, that the law forbade him to invade the czar, who
had done him no injury ; but to fuccour the king of
Sweden as an unfortunate prince in his dominions.
He fent his majefty 800 purfes, every one of which
amounted to 500 crowns, and advifed him to return
peaceably to his own dominions. Charles rejefled
this advice, threatening to hang up the balhaws, and
fhave the beards of any janizaries who brought him
fuch meffages, and fent wmrd that he fhould depend
upon the grand fignior’s promife, and hoped to re¬
enter Poland as a conqueror with an army of l urks.
C H A
After various intrigues at the Porte, an order *was Charlen
fent to attack this head of iron, as he was called, and -v—“-
to take him either alive or dead. He flood a fiege in
his houfe, with forty domeflics, againft the Turkifh
army ; killed no lefs than 20 janizaries with his own
hand ; and performed prodigies of valour on a very un-
neceffary and unwarrantable occafion. But the houfe
being fet on fire, and himfelf wounded, he was at
lafl taken prifoner, and fent to Adrianople, where
the grand fignior gave him audience, and promifed to
make good all the damages he had fuflained. At
lafl, after a flay of above five years, he left Turkey ;
and, having difguifed himfelf, traverfed Wallachia,
Tranfylvania, Hungary, and Germany, attended only
by one perfon : and in fixteen days riding, during which
time he never went to bed, came to Stralfund at mid¬
night, November 21. 1714. His boots were cut from
his fwollen legs, and he W’as put to bed ; where, when
he had flept fome hours, the firft thing he did wras to
review his troops, and examine the ftate of the fortifi¬
cations. He fent out orders that very day to re¬
new the war -with more vigour than ever. But af¬
fairs were now much changed : Auguftus had recover¬
ed the throne of Poland ; Sweden had loft many of its
provinces, and was without money, trade, credit, or
troops. The kings of Denmark and Pruffia feized the
ifiand of Rugen ; and befieged him in Stralfund,
which furrendered ; but Charles efcaped to Carlfcroon.
When his country was threatened with invafion by
fo many princes, he, to the furprife of all Europe,
marched into Norway with 20,000 men. A very
few Danes might have flopped the Swedifh army ; but
fuch a quick invafion they could not forefee. Europe
was yet more at a lofs to find the czar fo quiet, and
not making a defcent upon Sweden, as he had before
agreed with his allies. This inaflion was the confe-
quence of one of the greateft defigns, and at the fame
time the moft difficult of any that urere ever formed
by the imagination of man. In fhort, a fcheme was
fet on foot for a reconciliation with the czar ; for re¬
placing Staniflaus on the throne of Poland ; and fetting
James II.’s fon upon that of England, befides re-
ftoring the duke of Holflein to his dominions. Charles
was pleafed w'ith thefe grand ideas, though without
building much upon them, and gave his minifter
leave to a£l at large. In the mean time, Charles
was going to make a fecond attempt upon Norway in
1718 ; and he flattered himfelf with being mafler of
that kingdom in fix months ; but while he was exa¬
mining the works at Frederickfhall, a place of great
ftrength and importance, which is reckoned to be the
key of that kingdom, he was killed by a fbot from the
enemy, as has been generally believed,, though it has
been alfo reported that he fell by the treachery of one
of his own officers, who had been bribed for that pur-
pofe.
This prince experienced the extremes of profperity
and of adverfity, without being foftened by the one
or diflurbed for a moment at the other ; but was a man
rather extraordinary than great, and fitter to be ad¬
mired than imitated. He was honoured by the Turks
for his rigid abftinence from wine, and his regularity in
attending public devotion.
As to his perfon, he was tall and of a noble mein,
had a line open forehead, large blue eyes, flaxen hai?,
fail
t 4°5 1
Charles
C H A [ 406
fair complexion, a handfome nofe, but little beard,
and a laugh not agreeable. His manners were harfh
and aultere, not to fay favage : and as to religion, he
was indifferent towards all, though exteriorly a Lu¬
theran, and a ftrong believer in predeftination. A few
anecdotes will illuftrate his charafler. No dangers,
however great, made the leaf! impreffion upon him.
When a horfe or two were killed under him at the
battle of Narva, in 1700, he leaped nimbly upon frelh
ones, faying, “ Thefe people find me exercife.” One
day, when he was dilating letters to a fecretary, a
bomb fell through the roof into the next room of the
houfe where they were fitting. The fecretary, terri¬
fied left the houfe fhould come down upon them, let
his pen drop out of his hand : “ What is the matter?'’
fays the king calmly. The fecretary could only reply,
“ Ah, Sir, the bomb.” “ The bomb (fays the king) i
what has the bomb to do with what I am dilating to
you ! Go on.”
He preferved more humanity than is ufually found
among conquerors. Once, in the middle of an aftion,
finding a young Swedifh officer wounded and unable
to march, he obliged the officer to take his horfe, and
continued to command his infantry on foot. The
princefs Lubomirfki, who was very much in the intereft
and good graces of Auguftus, falling by accident into
the hands of one of his officers, he ordered her to be
fet at liberty : faying, “ That he did not make war with
■women.” One day, near Leipfic, a peafant threw
himfelf at his feet, with a complaint againft a grenadier,
that he had robbed him of certain eatables provided
for himfelf and his family. “ Is it true (faid Charles
fternly), that you have robbed this man ?” The fol-
dier replied, “ Sir, I have not done • near fo much
harm to this man as your majefty has done to his
mafter; for you have taken from Auguftus a kingdom,
whereas I have only taken from this poor fcoundrel a
dinner.” Charles made the peafant amends, and par¬
doned the foldier for his firmnefs : “ However, my
friend (fays he to him), you will do wTell to recolleft
that if I took a kingdom from Auguftus, I did not take
it for myfelf.”
Though Charles lived hardily himfelf, a foldier did
not fear to remonftrate to him againft fome bread,
which was very black and mouldy, and which yet was
the only provifion the troops had. Charles called for
a piece of it, and calmly ate it up faying, “ that it
was indeed not good, but that it might be eaten.”
From the danger he was in in Poland, when he beat
the Saxon troops in 1702, a comedy was exhibited at
Marienburg, where the combat was reprefented to the
difadvantage of the Swedes. “ Oh, (lays Charles,
hearing of it), I am far from envying them in this
pleafure. Let them beat me in the theatres as long
as they will, provided I do but beat them in the field.”
He wrote fome obfervations on war, and on his own
campaigns from 1700 to I7°9 • ^,u': '■^e MS* was loft
at the unfortunate battle of Pultowa.
CHARLES’S CAPE, a promontory of Virginia, in
North America, forming the northern headland of
the ftrait that enters the bay. of Chefapeak.
Charles's Fort, a fortrefs in the county of Corke,
and province of Munfter, in Ireland, fituated at the
mouth of Kinfale harbour. W. Long. 8. 20. N. Lat.
51. 21. *
I C H A
Charleston, the metropolis of South Carolina,Charlefton.
is the moft coniiderable town in the ftate *, fituated in
the diftridt of the fame name, and on the tongue of
land formed by the confluent ft reams of Aftfley and
Cooper, which are fliort rivers, but large and naviga¬
ble. Thefe waters unite immediately below the city,
and form a fpacious and convenient harbour j which
communicates with the ocean juft below Sullivan’s
iflandj which it leaves on the north, feven miles fouth-
eaft of Charlefton. In theie rivers the tide riles, in
common, about 64 feet j but uniformly rifes 10 or 12
inches more during a night tide. The faft is certain ;
the caufe unknown. The continual agitation which
the tides occafion in the waters which almoft furround
Charlefton, the refrelhing fea breezes which are re¬
gularly felt, and the fmoke arifing from fo many chim¬
neys, render this city more healthy than any part of
the low country in the fouthem ftates. On this ac¬
count it is the refort of great numbers of gentlemen,
invalids from the Weft India iflands, and of the rich
planters from the country, who come here to fpend
the fickly months, as they are called, in queft of health
and of the focial enjoyments which the city affords.
And in no part of America are the focial bleffings en¬
joyed more rationally and liberally than here. Unaf-
fedled hofpitality, affability, eafe of manners and ad-
drefs, and a difpofition to make their guefts welcome,
eafy, and pleafed with themfelves, are charafleriftics of
the refpedtable people of Charlefton. In fpeaking of
the capital, it ought to be obferved, for the honour of
the people of Carolina in general, that ■when in com¬
mon with the other colonies, in the conteft with Bri¬
tain, they refolved againft the ufe of certain luxuries,
and even neceffaries of life j thofe articles, which im¬
prove the mind, enlarge the underftanding, and cor-
re£t the tafte, were excepted 5 the importation of books
was permitted as formerly.
The land on which the town is built, is flat and
low, and the water brackilh and unwholefome. The
ftreets are pretty regularly cut, and open beautiful
profpe£ls, and have fubterranean drains to carry off
filth and keep the city clean and healthy 5 but are too
narrow for fo large a place and fo warm a climate.
Their general breadth is from 35 to 66 feet. The
houfes which have been lately built, are brick, with
tiled roofs. The buildings in general are elegant, and
moft of them are neat, airy, and well furnilhed. The
public buildings are, an exchange, a ftate-houfe, an
armoury, a poor-houfe, and an orphan’s houfe. Here
are feveral refpeftable academies. Part of the old
barracks has been handfomely fitted up, and converted
into a college, and there are a number of ftudents ;
but it can only be called as yet a refpeftable academy.
Here are two banks, a branch of the national bank,
and the South Carolina bank, eftabliftied in 1792. The
houfes for public worlhip are two Epifcopal churches,
two for Independents, one for Scotch Prefbyterians,
one for Baptifts, one for German Lutherans, two for
Methodifts, one for French Proteftants, a meeting-
houfe for Quakers, a Roman Catholic chapel, and a
Jewith fynagogue.
Little attention is paid to the public markets ; a
great proportion of the moft wealthy inhabitants hav¬
ing plantations from which they receive fupplies of al-
moft every article of living. The country abounds
with
Charles’s
Wain
II
Queen
Charlotte’s
111 and.
C H A
[ 407 ] C H A
with poultry and wild ducks. Their beef, mutton and
veal are not generally of the bell kind) and few filh
are found in the market.
In 1787, it was computed that there were 1600
houfes in this city, and 15,000 inhabitants, including
5400 Haves ; and what evinces the healthinefs of the
place, upwards of 200 of the white inhabitants wrere
above 60 years of age. In I79l> there were 16,359
inhabitants, of whom 7684 were Haves. This city
has often fuffered much by fire : the laft and moft de-
ftru&ive happened as late as June 179^*
Charlefton was incorporated in and divided
into three wards, which chofe as many wardens, from
among whom the citizens eleft an intendant of the
city. The intendant and wardens form the city-coun¬
cil, who have power to make and enforce bye-laws
for the regulation of the city.
The value of exports from this port, in the year
ending November 1787, amounted to 505,278!. 19s.
5d. fterling. The number of veflels cleared from the
cuftomhoufe the fame year, was 947* meafuring
62,118 tons $ 735 of thefe, meafuring 41,531 tons,
were American ; the others belonged to Great Bri¬
tain, Ireland, Spain, France, and the United Nether¬
lands.
Charles's lVainv vc^Aflronomy, feven flars in the
conftellation called CJrfa Majory or the Great Bear.
CHARLETON. an ifland at the bottom of Hud-
fon’s bay, in North America, fubjedl to Great Britain.
W. Long. 80. o. N. Lat. 52. 30.
Charleton, Walter, a learned Englifh phyfician,
born in 1619, was phyfician in ordinary to Charles I.
and Charles II. one of the firft members of the royal
fociety, and prefident of the college ot phyficians. He
wrote on various fubjedls 5 but at laft his narrow cir-
cumftances obliged him to retire to the ifland of Jer-
fey, where he died in 1707.
CHARLOCK, the Englilh name of the Rapha-
nus : it is a very troublefome weed among corn, be¬
ing more frequent than almoft any other. There are
two principal kinds of it: the one with a yellow flower,
the other with a white. Some fields are particularly
fubje6t to be overrun with it, efpecially thofe which
have been manured with cow dung alone, that being
a manure very favourable to the growth of it. The
farmers in fome places are fo fenfible of this, that they
always mix horfe dung with their cow dung, when they
ufe it for arable land. When barley, as is often the
cafe, is infefted with this weed to fuch a degree as
to endanger the crop, it is a very good method to mow
down the charlock in May, when it is in flower, cut¬
ting it fo low as juft to take off the tops of the leaves
of barley with it : by this means the^ barley will
get up above the weed: and people have got four
quarters of grain from an acre of fuch land as would
have fcarce yielded any thing without this expedient.
Where any land is particularly fubje6t to this weed,
the beft method is to fow it with grafs feed, and make
a pafture of it j for then the plant will not be trouble-
fome, it never growing where there is a coat of grafs
upon the ground.
^yeen CH .RLOTTE’s Island, an ifland in the
, South fea, firft difcovered by Captain Wallis in the
Dolphin, in 1767, who took poffeflkm of it in the
name of King George III, Here is good water, and
Charpen-
tier.
plenty of cocoa nuts, palm nuts, and fcurvy grafs. The Queen ^
inhabitants are of a middle ftature, and dark com-s
plexion, with long hair hanging over their ftioulders}
the men are well made, and the women handfome }
their clothing is a kind of coarfe cloth, or matting,
which they faften about their middle.
^ueen Charlotte's IJlands, a clufter of South fea
iflands, difcovered in 1767 by Captain Carteret. He
counted feven, and there were fuppofed to be many
more. The inhabitants of thefe iflands are defcribed
as extremely nimble and vigorous, and almoft as well
qualified to live in the water as upon land: they are
very warlike: and, on a quarrel with fome of Captain
Carteret’s people, they attacked them with great re-
folution } mortally wounded the mafter and three of
the failors; were not at all intimidated by the fire
arms j and at laft, nowithftanding the averfion of
Captain Carteret to ftied blood, he was obliged to fe-
cure the watering places by firing grape Ihot into the
'woods, which deftroyed many of the inhabitants.
Thefe ifl^nds lie in S. Lat. 11°. E. Long. 164°. They
are fuppofed to be the Santa Cruz of Mandana, who
died there in 1595.
CHA.RM, a term derived from the Latin carment
“ a verfe j” and ufed to denote a magic power, or fpell,
by which, with the afliftance of the devil, forcerers
and witches were fuppofed to do wonderful things,
far furpaffing the power of nature.
CHARNEL, or Charnel house, a kind of por¬
tico, or gallery, ufually in or near a churchyard, over
which wTere anciently laid the bones of the dead, after
the flefh was wholly confumed. Charnel-houles are
now ufually adjoining to the church.
CHARON, in fabulous hiftory, the fon of Erebus
and Nox, whofe office was to ferry the fouls of the
deceafed over the waters of Acheron, for which each
foul was to pay a piece of money. For this reafoa
the Pagans had a cuftom of putting a piece of money
into the mouth of the dead, in order that they might
have fomething to pay Charon for their paffage.
CH ARONDAS, a celebrated legiflator of the Thu-
rians, and a native of Catanea in Sicily, flouriftied 446
before Chrift. He forbade any perfon’s appearing
armed in the public affemblies of the nation ; but one
day going thither in hafte, without thinking of his
fword, he was no fooner made to obferve his miltake
than he ran it through his body.
CHAROST, a town of France, in Berry, with the
title of a duchy. It is feated on the river Arnon.
E. Long. 2. 15. N. Lat. 46. 56.
CHAROUX, a town of France, in the Bourbon-
nois, feated on an eminence, near the river Sioulle. It
has two parifhes, which are in different diocefes.
E. Long. 3. 15. N. Lat. 46. 10.
CHARPENTIER, Francis, dean of the French
academy, w’as born in 1620. His early capacity in¬
clined his friends to educate him at the bar : but he
was much more delighted with the ftudy of languages
and antiquity than of the law 5 and preferred repofe
to tumult. M. Colbert made ufe of him in eftabliftr-
ing his new academy of medals and infcriptions ; and
no perfon of that learned fociety contributed more
than himfelf toward that noble feries of medals which
were ftruck on the confiderable events that diftinguifh-
ed the reign of Louis XIV. He publilhed feveral
works,
Cl* an¬
ti
Charta.
C H A [ 408
work?) which were all well received 5 and died in
j CHARR. See Salmo, Ichthyology Index.
CHARRON, Peter, the author of a book entitled
Of IVifdorn, which gained him great reputation, was
born at Paris in the year 1541. After being advocate
in the parliament of Paris for five or fix years, he ap¬
plied himfelfto divinity ; and became fo great a preach¬
er, that the bifhops of feveral diocefes offered him the
high ell dignities in their gift* Ho died at Paris, fud-
denly in the ftreet, November 16. 1603.
CHART, or Sea Chart, an hydrographical map,
or a projeftion of fome part of the earth’s fuperficies in
piano, for the ufe of navigators.
Charts differ very confiderably from geographical or
land maps, which are of no ufe in navigation. Nor are
fea charts all of the fame kind, fome being what we
call plane charts, others IVEercator charts, and others
globular charts.
Plane Chart, is a reprefentation of fome part of the
fuperficies of the terraqueous globe, in which the me¬
ridians are fuppofed parallel to each other, the paral¬
lels of latitude at equal diftances, and confequently the
degrees of latitude and longitude everywhere equal to
each other. See Plane Chart.
Mercator's Chart, is that where the meridians are
ilraight lines, parallel to each other, and equidiftant j
the parallels are alfo ftraight lines, and parallel to
each other : but the diftance between them increafes
from the equinoftial towards either pole, in the ratio
of the fecant of the latitude to the radius. See Na¬
vigation.
Globular Chart, a meridional projeaion, wherein
the diftance of the eye from the plane of the meridian,
upon which the projection is made, is fuppofed to be
equal to the fine of the angle 450. This projection
comes the neareft of all to the nature of the globe, be-
caufe the meridians therein are placed at equal di¬
ftances ; the parallels alfo are nearly equidiftant, and
confequently the feveral parts of the earth have their
proper proportion of magnitude, diftance, and litua-
tion, nearly the fame as on the globe itfelf. See Glo¬
bular ProjeEhon.
Hydrographic Charts, (beets of large paper, where¬
on (everal parts of the land and fea are defcribed, with
their refpeCtive coafts, harbours, founds, flats, rocks,
(helves, fands, &c. together wdth the longitude and la¬
titude of each place, and the points of the compafs.
See Mercator's Chart.
Seltnographic Charts, particular defcriptions of the
fpots, appearances, and maculae of the moon. See A-
stronomy Index.
Topographic Charts, draughts of fome fmall parts
of the earth only, or of fome particular place, with¬
out regard to its relative fituation, as London, York,
&c-
CHARTA, or Carta, primarily figmfies a fort of
paper made of the plant papyrus or biblus. See Paper
and Charter.
Charta Emporetica, in Pharmacy, &c. a kind of
paper made very foft and porous, uied to filter with¬
al. See Filtration, &c.
Charta is alfo ufed in our ancient cuftoms for a
charter, or deed in writing. See Charter.
2
] C H A
Magna Charta, the great charter of the liberties of
Britain, and the bafis of our laws and privileges. ^
This charter may be faid to derive its origin from
King Edward the Confeffor, who granted feveral pri¬
vileges to the church and (late by charter . thefe liber¬
ties and privileges w;ere alfo granted and confirmed by
King Henry I. by a celebrated great charter now' loft j
but wdiich wTas confirmed or re-enafted by King Hen¬
ry II. and King John. Henry III. the fucceffor of this
laft prince, after having caufed 1 2 men make inquiry
into the liberties of England in the reign of Henry I.
granted a new charter *, wdiich was the (ame as the pre-
fent magna charta. This he feveral times confirmed,
and as often broke •, till, in the 37th year of his reign,
he wTent to ^Veftminfter Hall, and there, in prefence of
the nobility and biftiops, who held lighted candles in
their hands, magna charta was read, the king all the
time holding his hand to his bread, and at laft folemn-
ly fwearing faithfully and inviolably to obferve all the
things therein contained, &c. Then the bilhops ex-
tinguiftiing the candles, and throwing them on the
ground, they all cried out, “ Thus let him be extin-
gufthed, and (link in hell, who violates this charter.”
It is obferved, that, notwithftanding the folemnity of
this confirmation, King Henry, the very next year,
again invaded the rights of his people, till the barons
entered into a war againft him j when, after various
fuccefs, he confirmed this charter, and the charter or
the foreft, in the 52d year of his reign.
This charter confirmed many liberties of the church,
and redreffed many grievances incident to feodal te¬
nures, of no fmall moment at the time j though now,
unlefs confidered attentively and with this retrofpeft,
they feem but of trifling concern. But, befides thefe
feodal provifions, care was alfo taken therein to protect
the fubjed againft other oppreffions, then frequently
arifing from unreafonable amercements, from illegal
diftreffes or other procefs for debts or fervices due to
the crown, and from the tyrannical abufe of the pre¬
rogative of purveyance and pre-emption. It fixed the
forfeiture of lands for felony in the fame manner as it
dill remains; prohibited for the future the grants of
exclufive filheries; and the ereftion of new bridges fo
as to opprefs the neighbourhood. With refpeft to
private rights, it eftabliilred the teftamentary power
of the fubjeft over part of his perfonal eftate, the reft
being diftributed among his wife and children j it laid
down the law of dower, as it hath continued ever fince j
and prohibited the appeals of women, unlefs after
the death of their hulbands. In matters of public po¬
lice and national concern, it enjoined an uniformity of
weights and meafures ; gave new encouragements to
commerce, by the protection of merchant ftrangers;
and forbade the alienation of lands in mortmain. With
regard to the adminiftration of juftice •, befides prohi¬
biting all denials or delays of it, it fixed the court of
common pleas at Weftminfter, that the fuitors might
no longer be haraffed with following the king’s per-
fon in all his progreffes ; and at the fame time brought
the trial of iffues home to the very doors of the free¬
holders, by direfting aflizes to be taken in the proper
counties, and eftablilhing annual circuits : it alfo cor-
reaed fome abufes then incident to the trials by wager
of law and of battle j direfted the regular award¬
ing
Mag-na
Charta
C H A [ 409 ] G H A
Chattel ing of inquefts for life or member; prohibited the
I! king’s inferior minifters from holding pleas of the
Charter crownj or trying any criminal charge, whereby many
1Ki't/~ - forfeitures might otherwife have unjuftly accrued to
the exchequer ; and regulated the time and place of
holding the inferior tribunals of juftice, the county-
court, Iheriff’s torn, and court leet. It confirmed and
eftabliihed the liberties of the city of London, and all
other cities, boroughs, towns, and ports of the king¬
dom. And laftly (which alone would have merited
the title that it bears, of the great charter), it proteft-
ed every individual of the nation in the fr ee enjoyment
of his life, his liberty, and his property, unlefs declared
to be forfeited by the judgment of his peers, or the law
of the land.
This excellent charter, fo equitable, and beneficial
to the fubjeft, is the moft ancient written law in the
kingdom. By the 25th Edward I. it is ordained, that
it {ball be taken as the common law 5 and by the 43d
Edward III. all ftatutes made againft it are declared
to be void.
CHARTEL, in Law, a written inftrument, or evi¬
dence of things afted between one perfon and ano¬
ther. The word charter comes from the Latin charta,
anciently ufed for a public and authentic aft, a dona¬
tion, cmitraft, or the like ; from the Greek %xer^,
“ thick paper” or “ pafteboard,” whereon public afts
were wont to be written. Britton divides charters in¬
to thofe of the king, and thofe of private perfons.
1. Charters of the king, are thofe whereby the king
paffeth any grant to any perfon or body politic, as a
charter of exemption, of privilege, See. charter of pardon,
whereby a man is forgiven a felony, or other offence
committed againft the king’s crown and dignity j char¬
ter of the foref, wherein the laws of the foreft are
comprifed, fuch as the charter of Canutus, &c.
2. Charters of private perfons, are deeds and inftru-
ments for the conveyance of lands, &c. And the pur-
chafer of lands fhall have all the charters, deeds, and
evidences, as incident to the fame, and for the main¬
tenance of his title.
CHARTER-Govcrnments in America. See Colony.
CuARTER-Land, fuch land as a perfon holds by char¬
ter j that is, by evidence in writing j otherwife called
freehold.
CHARTERPARTY, in commerce, denotes the
inftrument of freightage, or articles of agreement for
the hire of a veffel. See Ireight, &c.
The charterparty is to be in writing j and to be fign-
ed both by the proprietor or the mafter of the {hip,
and the merchant who freights it. It is to contain the
name and the burden of the veflel j the names of the
mafter and the freighter *, the price or rate of freight $
and the time of loading and unloading 1 and the other
conditions agreed on. It is properly a deed, or poli¬
cy, whereby the mafter or proprietor of the veflel
engages to furnilh immediately a tight found veflel,
well equipped, caulked, and flopped, provided with an¬
chors, fails, cordage, and all other furniture to make
the voyage required, as equipage, hands, viftuals, and
other munitions; in confideration of a certain fum to
be paid by the merchant for the freight. Laftly, The
{hip with all its furniture, and the cargo, are reflec¬
tively fubjefted to the conditions of the charterparty.
The charterparty differs from a hill of lading, in that
Vql. V. Part II.
the firft is for the entire freight, or lading, and that Cnartophy-
both for going and returning ; whereas the latter is on-
ly for a part of the freight, or at moft only for the charybdis.
voyage one way. -y 
Boyer fayTs, the word is derived from hence, that
per medium charta incidebatur, et fc fiebat charta par¬
tita ; becaufe, in the time when notaries were lef$
common, there was only one inftrument made for
both parties : this they cut in two, and gave each
his portion 5 joining them together at their return, to *
know if each had done his part. 'Phis he obferves to
have been praftifed in his time } agreeable to the me¬
thod of the Romans, who, in their ttipulations, ufed to
break a ftaff, each party retaining a moiety thereof as
a mark.
CHARTOPHYLAX, the name of an officer of
the church of Conftantinople, who attends at the door
of the rails when the facrament is adminiftered, and
gives notice to the priefts to come to the holy table.
He reprefents the patriarch upon the bench, tries all
ecclefiaftical caufes, keeps all the marriage regifters,
affifts at the confecration of bilhops, and prefents the
bilhop eleft at the folemnity, and likewife all other
fubordinate clergy. I his office refembles in fome fhape
that of the hibliothecanus at Rome.
CHARTRES, a large city of France, in the pro¬
vince of Orleannois, fituated on the river Eure, in
E. Long. 1. 32. N. Lat. 48. 47. It is a bifhop’s fee.
CHARTREUSE, or Chartreuse grand, a ce¬
lebrated monaftery, the capital of all the convents of
the Carthufian monks, fituated on a fteep rock in the
middle of a large foreft of fir trees, about feven miles
north-eaft of Grenoble, in the province of Dauphiny
in France. E. Long. 5. 5- N. Lat. 45. 20. See Car¬
thusians.
From this mother-convent, all the others of the fame
order took their name j among which was the Char-
treufe of London, corruptly called the charterhoufe, now
converted into an hofpital, and endowed with a reve¬
nue of 600I. per annum.
Here were maintained 80 decayed gentlemen, not
under 50 years of age ; alfo 40 boys are educated and
fitted either for the univerfity or trades. Thofe fent
to the univerfity have an exhibition of 20I. a-year for
eight years : and have an immediate title to nine
church-livings in the gift of the governors of the hof¬
pital, who are fixteen in number, all perfons of the firft
diftinftion, and take their turns in the nomination of
penfioners and fcholars.
CHARTULARY, Chartularius, a title given
to an ancient officer in the Latin church, who had the
care of charters and papers relating to public affairs.
The chartulary prefided in ecclefiaftical judgments, in
lieu of the pope. In the Greek church the chartulary
was called chartophylax ; but his office was there much
more confiderable ; and fome even diftinguifh the char¬
tulary from the chartophylax in the Greek church. See
Chartophylax.
CHARYBDIS, in Ancient Geography, a whirlpool
in the ftraits of Meffina, according to the poets; near
Sicily, and oppofite to Soylla, a rock on the coaft of
Italy. Thucydides makes it to be only a ftrong flux
and reflux in the ftrait, or a violent reciprocation of
the tide, efpecially if the wind fets fouth. But on di¬
ving into the Charybdis, there are found vaft gulfs
3 -F and
C H A [41
Chafe, and whirlpools below, which produce all the commo-
' " v ' u-* tion on the furface of the water.
Charybdis is ufed by Horace to denote a rapacious
proftitute. „ .
CHASE, or Chace, in Law, is ufed for a driving
of cattle to or from any place j as to a diftrefs, or fort-
let, &c.
Chase, or Chace, is alfo a place of retreat for deer
and wild beafts ; of a middle kind between a foreft
and a park, being ufually lefs than a foreft, and not
poffeffed of fo many privileges 5 but wanting, v. g.
Seecourts of attachment, fwainmote, and juftice feat*.
Yet it is of a large extent, and ftocked both with a
greater diverftty of wild beafts or game, and more
keepers than a park. Crompton obferves, that a fo¬
reft cannot be in the hands of a fubjeft, but it forth¬
with lofes its name, and becomes chafe; in regard all
thofe courts lofe their nature when they come into the
hands of a fubjedtand that none but a king can make
a lord chief juftice in eyre of the foreft. See Justice
in Eyre.
The following hiftory of the Engliftr chafe is given
Britijb ]YJr Pennant. “ At firft the beafts of chafe had
Zool.1.^2. this wllole ;{|and for their range • they knew no other
limits than the ocean, nor confeffed any particular ma-
fter. When the Saxons had eftabliftred themfelves^ in
the heptarchy, they were referved by each fovereign
for his own particular diverfion. Hunting and war, in
thofe uncivilized ages, were the only employ of the
great} their a£tive, but uncultivated minds, being fuf-
ceptible of no pleafures but thofe of a violent kind,
fuch as gave exercife to their bodies, and prevented
the pain of thinking.
“ But as the Saxon kings only appropriated _ thofe
lands to the ufe ©f forejls which were unoccupied, fo
no individuals received any injury ; but when the Con-
queft had fettled the Norman line on the throne, this
paftion for the chafe was carried to an excefs, which
involved every civil right in a general ruin : it fuper-
feded the confideration of religion even in a fuperfti-
tious age : the village communities, nay even the moft
facred edifices, were turned into one vaft wafte, to
make room for animals, the objecfls of a lawlefs ty¬
rant’s pleafure. The new foreft in Hampfhire is too
trite an inftance to be dwelt on 5 fanguinary laws were
enafted to preferve the game j and in the reigns of
William Rufus, and Henry I. it was lefs criminal to
deftroy one of the human fpecies than a beaft of chafe.
Thus it continued while the Norman line filled the
throne ■, but when the Saxon line was reftored under
Henry II. the rigour of the foreft laws was immediate¬
ly foftened.
“ When our barons began to form a power, they
claimed a vaft, but more limited, traft for a diverfion
that the Englifh were always fond of. I hey were
very jealous of any encroachments on their refpe&ive
bounds, which were often the caufe of deadly feuds $
fuch a one gave caufe to the fatal day of Chevy-chafe ;
a fa£t which, though recorded only in a ballad, may,
from what we know of the manners of the times, be
founded on truth •, not that it was attended with all
the circumftances which the author of that natural but
heroic compofition hath given it} for, on that day
neither a Percy nor a Douglas fell: here the poet
feems to have clawed his privilege, and mixed with
o ] C H A
this fray feme of the events of the battle of Otter- Chafe.
bourne. .
“ When property became happily more divided
by the relaxation of the feodal tenures, thefe exten-
five hunting grounds became more limited j and as
tillage and huibandry increafed, the beafts of chafe
were obliged to give w'ay to others more ufeful to the
community. 1 he vaft traffs of land, before dedicat¬
ed to hunting, w7ere then contrafted 5 and, in propor¬
tion as the ufeful arts gained ground, either loft their
original deftination, or gave rife to the invention of
parks. Liberty and the arts feem coeval ; for when
once the latter got footing, the former prote&ed the
labours of the induftrious from being ruined by the li¬
centious fportfman, or being devoured by the obje£ts
of his diverfion : for this reafon, the fubje£ts of a def-
potic government ftill experience the inconvenien¬
ces of vaft waftes and forefts, the terrors of the
neighbouring hufbandmen j while in.our well regu¬
lated monarchy very few chafes remain. The Eng-
lifh ftill indulge themfelves in the pleafures of hunting*,
but confine the deer kind to parks, of w'hich England,
boafts of more than any other kingdom in Europe.
The laws allow7 every man his pleafure } but confine
them in fuch bounds as prevent them, from being in¬
jurious to the meaneft of the community. Before the
Reformation, the prelates feem to have guarded fuffi-
ciently againft this want of amufement, the fee of Nor¬
wich, in particular, being poffeffed, about that time,
of thirteen parks.”
Chase, in the fea language, is to purfue a Ihip j
which is alfo called giving chafe.
Stern-CHASE, is when the chafer follow’s the chafed
aftern dire&ly upon the fame point of the compafs.
To lie with a /hip's fore foot in a Chase, is to fail and
meet with her by the neareft diftance j and fo to crofs
her in her way, or to come acrofs her fore-foot.
A {hip is faid to have a good chafe, when fhe is fo
built forward on, or a-ftern, that ftie can carry many
guns to fhoot forwards or backwards ; according to
which the is faid to have a good forward or good fern
chafe. .
Chase Guns, are fuch whofe ports are either in tne
head (and then they are ufed in chafing of others) j or
in the ftern, which "are only ufeful when they are pur-
fued or chafed by any other Ihip.
Chase of a Gun, is the whole bore or length of a
piece taken withinfide.
Wild-goofe Chase, a term ufed to exprefs a fort of
racing on horfeback ufed formerly, which refembled
the flying of wild geefe ; thofe birds generally going
in a train one after another, not in confuted flocks as
other birds do. In this fort of race the two horfes,
after running twelve fcore yards, had liberty, which
horfe foever could take the leading, to ride what
ground the jockey pleafed., the hindmoft horfe being
bound to follow him within a certain diftance agreed
on by the articles, or elfe to be whipped in by the
tryers and judges who rode by and whichever boric
could diftance the other won the race. This fort of
racing was not long in common ufe *, for it was found
inhuman, and deftruttive to good horfes, when two
fuch were matched together. For in this cafe neither
was able to diflance the other till they were both
ready to fmk under their riders $ and often two very
good
C H A [ ' 411 ] (.< II A
Chafing good horfes were both fpoiled, and the wagers forced heart 5 but all to no purpofe. He then endeavoured < Chaftlty.
II to be drawn at laft. The mifchief of this fort of to extort her compliance by the moft terrible threat- v~””
Chaftity. rac;ng brought in the method now in ufe, of run- enings. It was in vain. She ftill perfifted in her re-
ning only for a certain quantity of ground, and deter- folution $ nor could die be moved even by the fear of
mining the plate or wager by the coming in firft at the death. But when the monfter told her that he would
firft defpatch her, and then having murdered a (lave,
Chasing of Gold, Silver, &c. See Enchasing. would lay him by her fide, after wftiich he would fpread
CHASTE tree. See Vitex, Botany Index. a report, that having caught them in the aft of adul-
CHASTITY •, Purity of the body, or freedom tery, he had punifhed them as they deferved •, this
from obfcenity.—The Roman larv juftifies homicide feemed to lhake her refolution. She hefitated, not
in defence of the chaftity either of one’s felf or rela- knowing which of thefe dreadful alternatives to take,
tions 5 and fo alfo, according to Selden, flood the law whether, by confenting to difhonour the bed of her
in the Jewdfti republic. Our law likewife juftifies a hulband, whom fhe tenderly loved ; or by refufing, to
woman for killing a man who attempts to ravifh her. die under the odious charafter of having proftituted
So the huifeand or father may juftify killing a man who her perfon to the luft of a fiave. He faw the ftruggle
attempts a rape upon his wife or daughter; but not of her foul *, and feizing the unlucky moment, obtain-
if he takes them in adultery by confent; for the one is ed an inglorious conqueft. Thus Lucretia’s virtue,
forcible and felonious, but not the other. which had been proof againft the fear of death, could
Chaftity is a virtue univerfally celebrated. There is not hold out againft the fear of infamy. The young
indeed no charm in the female fex that can fupply its prince, having gratified his paflion, returned home as in
place. Without it, beauty is unlovely, and rank is triumph. On the morrow, jLucretia overwhelmed with
contemptible ; good breeding degenerates into wan- grief and defpair, fent early in the morning to defire her
tonnefs, and wit into impudence. Out of the nume- father and her hulband to come to her and bring with
rous inftances of eminent chaftity recorded by authors, them each a trufty friend, affuring them there was no
the two following are felefted on account of the leffon time to lofe. They came with all fpeed, the one ac-
afforded by the different modes of conduft which they companied with Valerius (fo famous after under the
exhibit. name of Publicola), and the other with Brutus. The
Lucretia was a lady of great beauty and noble ex- moment (he faw them come, flie could not command
traftion ; (he married Collatinus, a relation of Tar- her tears; and when her hulband aiked her if all was
quinius Superbus king of Rome. During the fiege well ? “ By no means,” faid (lie, “ it cannot^be well
of Ardea, which lafted^much longer than was expefted, with a woman after (he has loft her honour. Yes, Col-
the young princes paffed their time in entertainments latinus, thy bed has been defiled by a ftranger : but
*Liv. 1. i. and diverfions. One day as they were at fupper *, at my body only B polluted : my mind is innocent, as
c. 56—60. Sextus Tarquin’s the king’s eldeft fon, with Colla- my death (hall witnefs. Promife me only not to fuffer
Dionyf. liv. t;nuSj Lucretia’s hufband, "the con verfation turned on the adulterer to go unpuniftied : it is Sextus Tarqui-
p. 261 merit of their wives : every one gave his own the nius, wTho laft night, a treacherous gueft, or rather cruel
iS- 1. iii. preference. “ What fignify fo many words ?” fays foe, offered me violence, and reaped a joy fatal to me j
9.*' Collatinus ; “ you may in a few hours, if you pleafe, but, if you are men, it will be ftill more fatal to him.”
be convinced by your owm eyes, how much my Lu- AH promifed to revenge her ; and at the fame time,
cretia excels the reft. We are young : let us mount our tried to comfort her wdth reprefenting, “That the
horfes, and go and furprife them. Nothing can bet- mind only fins, not the body ; and where the confent
ter decide our difpute than the ftate we (hall find them is wanting, there can be no guilt.” What Sextus
in at a time, when moft certainly they will not expeft deferves,” replies Lucretia, “ I leave you to judge ;
us.” They were a little warmed wdth wine : “ Come but for me, though I declare myfelf innocent of the
on, let us go,” they all cried together. They quickly crime, I exempt not myfelf from punilhment. No
galloped to Rome, which was about twenty miles from immodeft w’oman (hall plead Lucretia’s example to
Ardea, where they find the princeffes, wives of the outlive her diftionour.” Thus faying, (he plunged
voung’Tarquins, furrounded with company, and every into her bread a dagger (lie had concealed under her
circumftance of the higheft mirth and pleafure. From robe, and expired at their feet. Lucretia’s tragical
thence they rode to Collatia, where they faw Lucre- death hath been praifed and extolled by Pagan writers,
tia in a very different fituation. With her maids about as the higheft and moft noble aft of heroifm.. The
her, die was at work in the inner part of her hcufe, Gofpel thinks not fo : it is murder, even according to
talking on the dangers to which her hulband was ex- Lucretia’s owm principles, fince (lie puniftied with death
pofed. The viftory was adjudged to her unanimoufly. an innocent perfon, at leaft acknowledged as fuch by
She received her guefts with all poflible politenefs and herfelf. She was ignorant that our life is not in our
civility. ' Lucretia’s virtue, which (hould have com- own power, but in his difpofal from whom we receive
manded refpeft, was the very thing which kindled in it. St Auftin, who carefully examines, in his book De
the bread of Sextus Tarquin a ftrong and deteftable Civitate Dei, what we are to think of Lucretia’s death,
paflion. Within a few days he returned to Collatia 5 confiders it not as a courageous aftion (lowing from
and upon the plaufible excufe he made for his vifit, he a true love of chaftity, but as an infirmity of a woman
was received with all the politenefs due to a near rela- too fenfible of wordly fame and glory , and who, from
tion, and the eldeft fon of a king. Watching the fit- a dread of appearing in the eyes of men an accomplice
teft opportunity ^ he declares the paflion (he had excit- of the violence (he abhorred, a.id of a dime to which
ed at his laft vifit, and employed the moft tender entrea- (he was entirely a ftranger, commits a real crime upon
ties, and all the artifices poflible to touch a woman’s herfelf voluntarily and defignedly. But what cannot
3 F 2 be
J
Chateu-
Chinon.
C H A . t 41
Chiomara be fufficiently admired in this Roman lady, is her ab¬
horrence of adultery, which fhe feems to hold fo de-
teftable as not to bear the thoughts of it. In tnis
fenfe, Are is a noble example for all her fex. .
Chiomara, the wife of Ortiagon, a Gaulifli prince,
* was equally admirable for her beauty and chaftity.
During the war between the Romans and the Gauls,
A. R. 563, the latter were totally defeated on Mount
Olympus. Chiomara, among many other ladies, was
taken prifoner, and committed to the care of a centu¬
rion, no lefs paffionate for money than women. . He
at firft endeavoured to gain her confent to his infa¬
mous defires 5 but not being able to prevail upon Hr,
and fubvert her conflancy, he thought he might em¬
ploy force with a woman whom misfortune had redu¬
ced to flavery. Afterwards, to make her amends for
that treatment, he offered to refiore her liberty j but
not without ranfom. He agreed with her for a certain
fum, and to conceal this defign from the other Ro¬
mans, he permitted her to fend any of the prifoners (lie
fhould choofe to her relations, and affigned a place
near the river where the lady fhould be exchanged for
gold. By accident there was one of her own Haves
amongft the priioners. Upon him (lie fixed j and the
centurion foon after carried her beyond the advanced
ports, under cover of a dark night. T. he next evening
two of the relations of the princefs came to the place
appointed, whither the centurion alio carried his cap¬
tive. When they had delivered him the Attic talent
they had brought, which was the fum they had agreed
on, the lady, in her own language, ordered thofe wdro
came to recerve her to draw their fwords and kill tire
centurion, w7ho was then amufing himfelf with weigh¬
ing the gold. Then, charmed with having revenged
the injury done her chaftity, fhe took the head of the
officer, which ffie had cut off with her own hands, and
hiding it under her robe, went to her hufband Ortiagon,
who had returned home after the defeat of his troops.
As foon as ffie came into his prefence, ffie threw the
centurion’s head at his feet. He was ftrangely fur-
prifed at fuch a fight : and afked her whofe head it
was, and what had induced her to do an aft fo un¬
common to her fex ? With her face covered with a hid¬
den bluffi, and at the fame time exprefling her fierce
indignation, ffie declared the outrage which had been
done her, and the revenge {he had taken for it. Dur¬
ing the reft of her life, ffie ftedfaftly retained the fame
attachment for the purity of manners which conftitutes
the principal glory of the fex, and nobly fuftained the
honour of fo glorious, bold, and heroic an aftion.
This lady was much more prudent than Lucretia, in
revenging her injured honour by the death of her ra-
vaifher, rather than by her own. Plutarch relates this
faft, in his treatife upon the virtue and great aftions
of women ; and it is from him we have the name of
this, which is ivell worthy of being tranfmitted to po-
fterity.
The above virtue in men is termed continence. See
Continence.
CHATEAU-briant, a town of France in Brit¬
tany, w’ith an old caftle. W. Long. 1. 20. N. Lat.
47. 40.
CHATEAV-Chinon, a town of France in Nivernois,
and capital of Morvant, with a confiderable manufac¬
ture of cloth. E. Long. 3. 48. N. Lat. 47. 2.
2 ] C H A
Chateav-Dauphin, a very ftrong caftle of Piedmont Chat^a-
in Italy, and in the marquifate of Saluces, belonging n
to the king of Sardinia. It was taken by the com- Chatham.
bined army of France and Spain in 1744,-and was re- ^ 
ftored by the treaty of Aix-la-Chapelle. . ,
CiiATEAU-du-Loire, a town of 1( ranee, m Maine,
famous for fuftaining a fiege of feven years againft the
Count of Mans. It is feated'on the river Loire, in L.
Long. o. 25. N. Lat. 47. 40.
Chateau-Duu, an ancient town of France, and ca¬
pital of the Dunois, with a caftle and rich monaftery ;
feated on an eminence near the river Loire, in E. Long.
I. 26. N. Lat. 48. 4.
CuATEAV-Neuf, the name of feveral towns of France,
viz. one in Perche j another in Angumois, on the
river Charente, near Angoulefme j a third in Berry,
feated on the river Cher j and feveral other fmall
places.
CHATEAU-Portien, a town of France, in Champagne,
and in a diftrift called Portien, ■with a cattle built on
a rock, near the river Aifne. E. Long. 4. 23. N. Lat.
49. 35.
CHATEAu-Penaud, a town of France, in tne Gate-
nois, where clothes are made for the army, and where
there is a trade in faffron. E. Long. 4. 25. N. Lat.
48. o. This is alfo the name of a town of Touraine, in
France, with the title of marquifate. E. Long. 2.
41. N. Lat. 47. 22.
Chateau-Roux, a town of France, in Berry, with
the title of a duchy. It has a cloth manufafture, and
is feated in a very large pleafant plain on the river
Indre, in E. Long. 1. 47. N. Lat. 46. 49.
CuATEAU-Phiery, a town of France, in Champagne,
with the title of a duchy, and a handfome caftle on an
eminence, feated on the river Maine, in E. Long. 3.
23. N. Lat. 49. 12.
CaATEAU-Vi/ain, a town of h ranee, in Champagne,
with a caftle, and the title of a duchy 5 feated on the
river Anjou. E. Long. 2. 59. N. Lat. 48. o.
CHATEL, or C hate, a towm of Lorraine, in the
Vofque, feated on the river Mofelle, eight miles from
Mirecourt.
Chatel-Allan, a maritime town of France, in Sain-
tonge, five miles from Rochelle formerly very confi¬
derable, but now greatly decayed.
CtSATEL-Chalon, atownof France, in Tranche Comte,
remarkable for its abbey of Benediftine nuns. E. Long.
5. 25. N. Lat. 46. 50.
CHATELET, a town of the Netherlands, in Na¬
mur, feated on the Sambre, in the biffiopric of Liege.
E. Long. 4. 28. N. Lat. 50. 25.
Chatelet, the name of certain courts of juftice
eftabliffied in feveral cities in France. The grand
chatelet at Paris is the place where the prefidial or
ordinary court of juftice of the provoft of Paris is kept ;
confifting of a prefidial, a civil chamber, a criminal
chamber, and a chamber of policy, d he little chatelet
is an old fort, now ferving as a priion.
CHATELLERAULT, a town of France, in Poi¬
tou, with the title of a duchy •, feated in a fertile and
pleafant country, on the river Vienne, over which there
is a handfome rtone bridge. E. Long. o. 40. N. Lat.
46. 34.
CHATHAM, a town of Kent, adjoining to Ro-
chefter, and feated on the liver Medway. It is the
principal
C H A [ 4i3 1 c H A
Chatigan principal ftation of the royal navy 5 and the yards and ed with his ufual fignatnre, D. B. that is, Dunbelmus Chattertw.
11 magazines are furnilhed with all kinds of naval ftores, Brijlohenjis. i he former contains fliovt extrads ^irora
Chatterton. a$ well as materials for building and rigging the largeft two MSS. “ written 300 years ago by one Rowley^ a
' ^ ' men 0f war. The entrance into the river Medway monk,” concerning drefs in the age of Henry II. ; the
is defended by Sheernefs and other forts ; notwith- latter, “ Ethelgar, a Saxon poem,” in bombaft prole.
Handing which, the Dutch fleet burnt feveral fhips of In the fame magazine for May 1769, are three commu-
war here in the reign of Charles II. after the peace of nications from Briltol, with the fame fignatine D. B»
Breda had been agreed upon. In the year 1757, by one of them entitled “ Obfervations upon Saxon He-
dire&icm of the duke of Cumberland, feveral addition- raldry, with drawings of Saxon Achievements j” and
al fortifications were begun at Chatham ; fo that now in the fubfequent months of 1769 and 1770, there are
the fhips are in no danger of an infult either by land feverai other pieces in the lame magazine, whicn a,c.
or water. It has a church, a chapel of eafe, and a undoubtedly of his compofition.
Ihip ufed as a church for the failors. It has likewife In April 1770, he left Briftol, difgufled with his
about 500 houfes, moftly low, and built with brick j profellion, and irreconcilable to the line of life m
the ftreets are narrow, and paved j and it contains which he was placed ; and coming to London in hopes
about 3000 inhabitants. The principal employment of of advancing his fortune by his pen, he funk at once
the labouring hands is fhip-building in the king’s yard from the fublimity of his views to an abfolute depen-
and private docks. This town gave title of earl to dence on the patronage of bookfellers. 1 hings how-
that great Hatefman William Pitt in the reigns of ever, feem foon to have brightened up a little with him j
Geor re II. and III. E. Long. o. 40. N. Lat. 51. for, May 14. he writes to his mother, in high fpints,
20 b upon the change of his fituation, with the following
CHATIGAN, a town of Afia, in the kingdom of farcaftic refleftion upon his former patrons at BriftoL
Bengal, on the moft eafterly branch of the river Gan- “ As to Mr , Mr , Mr , Sec, &c. they
pes. It is but a poor place, though it was the firlt rate literary lumber fo low, that I believe an author,
the’ Portuguefe fettled at in thefe parts, and who Hill in their eftimation, muft be poor indeed : but here
keep a fort of poffeffion. It has but a few cotton ma- matters are otherwife. Had Rowley been a Londoner
nufa&ures •, but affords the beft timber for building of inftead of a Briftowyan, I could have lived by copying
any place about it. The inhabitants are fo fulpicious his works.” In a letter to his lifter, May 30. he informs
of each other, that they always go armed with a her that he is to be employed in writing a voluminous
fword, ptftol, and blunderbufs, not excepting the priefts. Hiftory of London, to appear m numbers the begin-
It is fubiea to the Great Mogul. E. Long. 91. 10. ning of next winter. Meanwhile, he had written fome-
N. Lat. 23. o. thinS in Praife of Bechford, then lord mayor, which
CH ATILLON sur Seine, a town of France, in had procured him the honour of being prefented to his
Burgundy, divided into two by the river Seine. It is lordlhip ; and, in the letter juft mentioned, he gives
32 miles from Langres, and 40 from Dijon ; and has the following account of his reception with certain
iron works in its neighbourhood. E. Long. 4. 33. obfervations upon political writing. “ 1 he lord mayor
N Lat 47 4:. received me as politely as a citizen could : but the devil
CHATRE a town of France, in Berry, feated on of the matter is, there is no money to be got on this
the river Indre, 37 miles from Bourges. It carries fide of the queftion.—However, he is a poor author
on a confiderable trade in cattle. E. Long. 1. 55. who cannot write on both fides.—ElTays on the patriotic
N Lat 46. 3 3. ficle wil1 fetch no m®re than what,ttie copy is fold for.
CHATTELS, a Norman term, under which were As the patriots themfelves are fearching for places,
anciently comprehended all moveable goods j thofe im- they have no gratuity to fpare.—On the other hand,
moveable being termed fief or fee. unpopular eflfays will not even be accepted, and you muft
Chattels, in the modern fenfe of the word, are pay to have them printed j but then you ieldom loie
all forts of o-oods, moveable or immoveable, except fuch by it, as courtiers are fo fenftble 01 their deficiency in
as are in the nature of freehold. merit, that they generoufly reward all who know how
CHATERER. See Ampelis, Ornithology /«- to daub them with the. appearance of it.”
‘ He continued to write incefiantly in various perio-
CHATTERTON, Thomas, a late unfortunate dical publications. July txth, he tells his filler that
poet whofe fate and performances have excited in no he had pieces laft month in feveral magazines ; in The
fm dl degree the public attention, as well as given rife Gofpel Magazine, The Town and Country, The Court
to mu-h literary controverfy. He was born at Briftol, and City, The London, the Political Regifter, &c.
Nov 2b. 1752 ; and educated at a charity fchool on But all thefe exertions of his genius brought in fo little
St Auguftine’s Back, where nothing more was taught profit, that he was foon reduced to the extremeft indi-
than reading, writing, and accounts. At 14 years of gencey fo that at laft, opprelTed with poverty and
age, he was articled clerk to an attorney at Briftol, difeafe, in a fit of defpair he put an end to his exift-
with whom he continued about three years ; yet, though ence, Auguft 1770, with a.dofe of poifon. This un-
his education was thus confined, he diicoveted an early fortunate perfon, though certainly a moft extraordin«ry
turn towards poetry and Enghfh antiquities, and parti- genius, feems yet to have been a moft ungracious com-
cularly towards heraldry. How foon he began to be pofition. He was violent and impetuous to a ftrange
an author is not known. In the Town and Country degree. From the firft of the above cited letters he
Magazine for March 1769, are two letters, probably feems to have had a portion of ill humour and fple-m
from him, as they are dated from Briftol, and fubferib- more than enough for a lad of 17 ; and the editor c€
C H A [41
•Chatterton. his Mifcellanies records, “ that he pofleffed all the vi-
' ces and irregularities of youth, and that his profligacy
was at leaft as confpicuous as his abilities.”
In 1777 were publiflied in one volume Bvo, “ Poems,
fuppofed to have been written at Briftol, by 1 homas
Rowley and others, in the 15th century : the greateft
part now firlt publilhed from the moft authentic copies,
with an engraved fpecimen of one of the MSS. To
which are added, a Preface, an introduftory Account
of the feveral Pieces, and a Gloffary.” And in 1778,
were publifhed, in one volume Bvo, “ Mifcellanies in
Profe and Verfe by Thomas Chatterton, the fuppofed
author of the Poems publifhed under the names of
Rowley, &c.”
Of Rowley’s poems, we have the following account
in the preface, given in the words of Mr George Cat-
cot of Briftol, to whom, it is faid, the public is in¬
debted for them. “ The firft difcovery of certain MSS.
having been depofited in Redclift church above three
centuries ago, was made in the year 1768, at the time
of opening the new bridge at Briftol ; and was owing
to a publication in Farley’s Weekly Journal, Oft. ift,
containing an account of the ceremonies obferved at
the opening of the old bridge, taken, as it was faid,
from a very ancient MS. This excited the curiofity
of fome perfons to inquire after the original. The
printer, Mr Farley, could give no account of it, or of
the perfon who brought the copy } but, after much in¬
quiry, it was difcovered that this perfon was a youth
between 15 and 16 years of age, whofe name was
Thomas Chatterton, and whofe family had been fex-
tons of Redclift church for near 150 years. His fa¬
ther, who was now dead, had alfo been mafter of the
free fchool in Pile ftreet. The young man was at firft
very unwilling to difcover from whence he had the ori¬
ginal : but, after many promifes made to him, was at
laft prevailed on to acknowledge that he had received
this, together with many other MSS. from his father,
who had found them in a large cheft in an upper room
over the chapel, on the north fide of Redclift church.”
It is added, that foon after this Mr Catcot commenced
an acquaintance wdth Chatterton, and partly as pre-
fents, partly as purchafes, procured from him copies
of many of his MSS. in profe and verfe ; as other co¬
pies were difpofed of in like manner to others. It is
concluded, however, that whatever may have been
Chatterton’s part in this very extraordinary tranfaftion,
whether he was the author, or only (as he eonftantly
afierted) the copier of all thefe produftions, he appears
to have kept the fecret entirely to himfelf, and not to
have put it in any one’s power to bear certain teftimo-
ny either of his fraud or of his veracity.
This affair, however, hath fince become the founda¬
tion of a mighty controverfy among the critics, which
hath yet fcarcely fubfided. The poems in queftion,
publilhed in 1777, were republifhed in I77^j with an
“ Appendix, containing fome obfervations upon their
language tending to prove that they w'ere written,
not by any ancient author, but entirely by Chatter¬
ton.”" Mr Warton, in the third volume of his Hiftory
of Englifh Poetry, hath efpoufed the fame fide of the
queftion. Mr Walpole alfo obliged the wmrld with a
Letter on Chatterton, from his prefs at Straw-berry hill.
On the other hand have appeared, “ Obfervations” up¬
on thefe poems, “ in which their authenticity is afcer-
1
4 ] C H A
tained,” by Jacob Bryant, Efq; 1781, 2 vols. 8\'0. j Chaucer. ^
and another edition of the “ Poems, w-ith a Comment,1 1 v "li>
in which their antiquity is confidered and defended, by
Jeremiah Miiles, D. D. dean of Exeter, 1782,” 4to.
In anfwer to tbefe two works, we have had three
pamphlets: 1. “ Curfory Obfervations on the Poems,
and Remarks on the Commentaries of Mr Bryant and
Dr Miiles ; with a falutary propofal addreffed to the
friends of thofe gentlemen.” 2. “ An Archaeological
Epiftle to Dean Miiles, editor of a fuperb edition of
Rowley’s Poems, &c.” 3. “ An Inquiry into the au¬
thenticity of the Poems attributed to Thomas Rowley,
in which the Arguments of the deans of Exeter and Mr
Bryant ate examined, by Thomas Whrton j” and other
pieces in the public prints and magazines : All prepa¬
ratory to the complete fettlement of the bufinefs in
“ A Vindication of the Appendix to the Poems called
Rowley’s, in reply to the Anfwers of the dean of Exe¬
ter, Jacob Bryant, Efq-, and a third Anonymous Wri¬
ter ; with fome further Obfervations upon thofe Poems,
and an Examination of the Evidence which has been
produced in fupport of their Authenticity. By Tho¬
mas Tyrwhitt, 1782,” 8vo.
CHAUCER, SiRGEOFREY,an eminent Englilh poet
in the 14th century, born at London in 1328. After
he left the univeifity, he travelled into Holland, France,
and other countries. Upon his return he entered him¬
felf in the Inner Temple, where he ftudied the muni¬
cipal laws of England. His firft ftation at court was
page to Edward HI. and he had a penfion granted
him by that prince till he could otherwife provide for
him. Soon after w-e find him gentleman of the king’s
privy chamber next year, ftiield-bearer to the king.
Efteemed and honoured, he fpent his younger days in
a conftant attendance at court, or for the moft part liv¬
ing near it, in a fquare ftone houfe near the park-gate
at Woodftock, ftill called Chaucer's Houfe.
Soon after, having got the duke of Lancafter for
his patron, Chaucer began every day to rife in great-
nefs. In 1373, he was fent with other perfons to the
republic of Genoa to hire fhips for the king’s navy
(our want of fhipping in thofe times being ufually ap¬
plied by fuch means) •, and the king was fo well fatis-
fied with his negotiation, that, on his return, he ob¬
tained a grant of a pitcher of wine daily in the port
of London, to be delivered by the butler of England j
and foon after was made comptroller of the cuftoms
for wool, wool fells, and hides ; an office which he
difcharged with great diligence and integrity. At this
period,°Chaucer’s income was about 1000I. a-year j
a fum which in thofe days might well enable him to
live, as he fays he did, with dignity in office, and hof-
pitality among his friends. It was in this meridian
blaze of profperity, in perfeft health of body and peace
of mind, that he wrote his moft humorous poems.
His fatires againft the priefts were probably written to
oblige his patron the duke of Lancafter, who favoured
the caufe of Wickliff, and endeavoured to expofe the
clergy to the indignation of the people. In the laft;
year of Edward III. our poet was employed in a com-
miffion to treat with the French ; and in the begin¬
ning of King Richard’s reign, he was in fome degree of
favour at court.
The duke of Lancafter at laft finding his views
checked, began to abandon Wickliff’s party : upon
which
C H A [41
Chaucer, which Chaucer likewise, how much foever he had
 v—- efpoufed that divine’s opinions, thought it prudent to
conceal them more than he had done. With the
duke’s intereft that of Chaucer entirely funk ; and the
former paffing over fea, his friends felt all the malice of
the oppofite party. Thefe misfortunes occafioned his
writing that excellent treatife, The 'Tejlament of Love
in imitation of Boethius on the Confolation of Philofo-
phy. Being much reduced, he retired to Woodftock,
to comfort himfelf with ftudy, which produced his ad¬
mirable treatife of the Afrolabe.
The duke of Lancafter at lad furmounting his trou¬
bles, married Lady Catharine Swynford, lifter to Chau¬
cer’s wife j fo that Thomas Chaucer, our poet’s fon,^
became allied to moft of the nobility, and to feveral of
the kings of England. Now the fun began to ftiine
upon Chaucer with an evening ray \ for by the influ¬
ence of the duke’s marriage, he again grew to a con-
fiderable (hare of wealth. But being now 70, he re¬
tired to Dunnington caftle near Newbury. He had
not enjoyed this retirement long before Henry IV. fon
of the duke of Lancafter, aflumed the crown, and in
the firft year of his reign gave our poet marks of his
favour. But however pleafing the change of affairs
might be to him at firft, he afterwards found no fmall
inconveniences from it. The meafures and grants of
the late king were annulled : and Chaucer, in or¬
der to procure frefh grants of his penfions, left his re¬
tirement, and applied to court : where, though he
gained a confirmation of fome grants, yet the fatigue
of attendance, and his great age, prevented him from
enjoying them. He fell fick at London : and ended
his days in the 72d year of his age, leaving the world
as though he defpifed it, as appears from his fong of
Flie from the Prefe. The year before his death he had
the happinefs, if at his time of life it might be fo call¬
ed, to fee the fon of his brother-in-law (Hen. IV.) feat-
ed on the throne. He was interred in Weftminfter ab¬
bey, and in 15 <;6, Mr Nicholas Bingham, a gentleman
of Oxford, at his own charge, ere6led a handfome mo¬
nument for him there. Caxton firft printed the Can¬
terbury Tales j but his works were firft colle&ed and
publilhed in one volume folio, by William Thynne,
London, 1542. They were afterwards reprinted in
1561, 1598, 1602. Oxford, 1721.
Chaucer was not only the firft, but one of the beft
poets which thefe kingdoms ever produced.^ He was
equally great in every fpecies of poetry which he at¬
tempted ; and his poems in general poffefs every kind
of excellence, even to a modern reader, except me¬
lody and accuracy of meafure ; defedfts which are to be
attributed to the imperfeft ftate of our language, and
" the infancy of the art in this kingdom at the time when
he wrote. “ As he is the father of Englifti poetry
("fays Mr Dryden) fo I hold him in the fame degree of
veneration as the Grecians did Homer, or the Romans
Virgil. He is a perpetual fountain of good fenfe,
learned in all fciences, and therefore fpeaks properly on
all fubjefts. As he knew what to fay, fo he knows alfo
when to leave off; a continence which is praflifed by
few writers, and fcarcely by any of the ancients, ex¬
cept Virgil and Horace.” This character Chaucer cer¬
tainly deferved. He had read a great deal; and was a
man of the world, and of found judgment. He was
the firft; Englifti poet who wrote poetically} as Dr John-
5 1 c H A
fon obferves in the preface to his Diflionary, and (he Cnalas
might have added) who wrote like a gentleman. He
had alfo the merit of improving our language confider-
ably, by the introdu£tion and naturalization of words
from the Provencal, at that time the moft poliftied dia¬
led in Europe.
CHALCIS, in Ancient Geography, the country of
the Chauci, a people of Germany : divided into the
Minores, now Eaf Friefand, and the county of Olden¬
burg ; and into the Majores, now the duchy of Bre¬
men and a part of Lunenburg.
CHAUD Medley, in Law, is of much the fame im¬
port with Chance Medley. The former in its etymo¬
logy fignifies an affray in the heat of blood or paflion :
the latter, a cafual affray. The latter is in common
fpeech too often erroneoufly applied to any manner of
homicide by mifadventure ; whereas it appears by
the flat. 24 Hen. VIII. c. 5. and ancient books
(Standf. P. C. 16.), that it is properly applied to fuch
killing as happens in felf-defence upon hidden encoun-
t-C i • f*
CHAL, a town of the Eaft Indies, on the coaft of
Malabar, in the province of Blagana, and kingdom of
Vifapour. Its river affords a good harbour for fmall
veffels. The town is fortified, and fo is the ifland on
the fouth fide of the harbour. It had formerly a good
trade, but is now miferably poor. It was taken by the
Portuguefe in 1507, to whom it ftill belongs. It is 15
miles fouth of Bombay, and five miles from the fea.
E. Long. 72. 45. N. Lat. 18. 30.
CHAULIEU, William Amfryede, Abbe
d’Amale, one of the moft polite and ingenious of the
French poets, was born in !639> anc^ ^'ec^ at aSe
of 84. The moft complete edition of his poems is that
printed in two vols. 8vo. in 1733*
CHAUMONT, a town of France, in Champagne,
and in the diftrift of Baflignq of which it is the capi¬
tal. It is feated on a mountain near the river Marne.
E. Long. 5. 15. N. Lat. 48. 6.
CHAUNE, a town of France, in Picardy, and in
the diftria of Sanfterre, with the title of a duchy. E.
Long. 2. 55. N. Lat. 49. 45.
CHAUNTRY. See Chantry.
CHAUNY, a town of Fiance, in Picardy, feated
on the river Oile, in Chantry. E. Long. 3. 17. N*
Lat. 49. 37. . .
CHAUVIN, Stephen, a celebrated mimfterof the
reformed religion, born at Nifmes, left France at the
revocation of the edia of Nantz, and retired to Rot¬
terdam, where he began a new ’journal des Sgavans ;
and afterwards removing to Berlin, continued it there
three years. At this laft place, he was made profef-
for of philofophy, and difcharged that office wfth much
honour and reputation. His principal work is a phi-
lofophical di&ionary, in Latin, which he published at
Rotterdam in 1692 ; and gave a new edition of it much
augmented, at Lewarden, in 1703, folio. He died in
1723, aged 83.
CHAVEZ, a ftrong town ofTralos-Montes in Por¬
tugal, feated at the foot of a mountain on the river
Tamega. It has two fuburbs, and as many forts;
one of which looks like a citadel. Between the town
and fuburb of Magdalena, is an old Roman ftone bridge
about 92 geometrical paces long. W. Long. 7. !•
N. Lat. 41. 45.
CHAZELLES,
C H A
Cfnazelle?, CHAZELLES, Joan Matthew,
Chazinza- mathematician and engineer, was born at Lyons
rians- in 1657. M. du Hamel, with whom he got acquaint-
* " ~v cd, finding his genius incline towards aftronomy, pre-
fented him to M. Caflini, who employed him in his ob-
fervatory. In 1684, the duke of Mortemar made ufe
of Chazelles to teach him mathematics ; and, the year
after, procured him the preferment of hydrography
profeffor for the galleys of MarfeUles, where he let
up a fchool for young pilots defigning to lerve abroad
the galleys. In 1686, the galleys made four little
campaigns, or rather four courfes, purely for exerche.
Chazelles went on board every time with them .. kept
his fchool upon the fea, and Ihow’ed the practice of
what he taught. In the years 1687 and 1688, he made
two other fea campaigns, in which he drew a gieat
many plans of ports, roads, towms, and forts, which
were lodged with the minifters of Hate. At the be¬
ginning of the w’ar, which ended with the peace of
Ryfvvick, fome marine officers, and Chazelles among
the reft, fancied the galleys might be fo contrived as
to live upon the ocean •, that they might ferve to tow
the men of wTar w?hen the wfind failed or proved con¬
trary, and alfo help to fecure the coaft of hiance upon
the ocean. Chazelles was fent to the weft coafts m
July 1689, to examine the prafticablenefs of this
icheme 5 and in 1690, fifteen galleys new built fet fail
from Rochefort, and cruifed as far as Torbay, in Eng-
and, and proved ferviceable at the defeent upon 1 in¬
mouth. After this, he digefted into order the ob-
fervations he had made on the coafts of the ocean j
and drew diftina: maps, with a portulan to them, viz.
a large defeription of every haven, of the depth, the
tides, the dangers and advantages difeovered, &c.
Thefe maps were inferted in the Neptune Frangoife,
publiffied in 1692, in which year Chazelles was engi¬
neer at the defeent at Oneille. In 1693, Monfieur
de Pontchartrain, then fecretary of ftate for the ma¬
rine, and afterwards chancellor of France, refolved
to get the Neptune Frangoife carried on to a fecond vo-
luine, which was alfo to take in the Mediterranean.
Chazelles defired that he might have a year’s voyage
on this fea, for making aftronomical obfervations 5
and the requeft being granted, he palled by Greece,
Egypt, and the other parts of Turkey, with his quadrant
. and telefcope in his hand. When he was in Egypt,
he meafured the pyramids : and finding the fides of the
largeft precifely facing the four cardinal points, natu¬
rally concluded this pofition to have been intended, and
alfo that the poles of the earth and meridians had not
fince deviated. Chazelles likewife made a report of his
voyage in the Levant, and gave the academy all the
fatisfaftion they wanted concerning the pofition of
Alexandria : upon which he was made a member of
the academy in 1695. He died in 1710.
CHAZINZARIANS, a fed of heretics who rofe
in Armenia in the feventh century. I he word is
formed of the Armenian chu%iis^ ii crofs. FLey aie
alfo called Jlaurolatrce, which in Greek fignifies the
fame as Cha'zin'zarians in Armenian, viz. adorers^ of
the crofs ; they being charged with paying adoration
to the crofs alone. In other refpe&s they were Nefto-
rians j and admitted two perfons in Jefus Chrift.
cephorus aferibes other fingularities to them } particu¬
larly their holding an annual feaft in memory of the
[ 416 ] C H A
a celebrated dog of their falfe prophet Sergius, wffirch they called CheLpeak
Check.
✓7 ** / o' 7/7/7 »*/ry p r
CHESAPEAK bay, in North America, the en¬
trance betwreen Cape Henry and Cape Chailes, run¬
ning up 300 miles between Virginia and Maryland.
It is navigable almoft all the way for large ffiips, and
has feveral navigable rivers that fall into it, by means
of wdiich (hips go up to the very doors of the planters,
to take in their lading of goods.—Here was a fea en¬
gagement in 1781 between the Britiih fieet under Ad¬
miral Graves confifting of 19 fliips of the line, and
the French fleet of 24 line-of-battle fhips under the
Count de Graffe, which ended in the Count’s keeping
poffeffion of the bay, by which Lord Cornwallis and
his whole army wTere made prifoners of war at V ork-
town, being invefted both by fea and land by very fu-
perior numbers.
CHEATS, are deceitful praaices in defrauding, or
endeavouring to defraud, another of his known right,
by means of fome artful device, contrary to the plain
rules of common honefty : as by playing with falls
dice, or by caufing an illiterate perfon to execute a
deed to his prejudice, by reading it over to him in
wmrds different from thofe in which it wjas written,
gcc. If any perfon deceitfully get into his hands or
poffeffion any money or other things of any other per-
fon’s, by colour of any falfe token, See. being convia-
ed, he ftiall have fuch puniftiment by imprifonment,
fetting upon the pillory, or by any corporeal pain ex¬
cept pains of death, as (hall be adjudged by the per¬
fons before whom he (hall be convifted.——As there are
frauds which may be relieved civilly, and not punifhed
criminally j fo there are other frauds which in a fpe-
cial cafe may not be helped civilly, and yet fhall be pu¬
nifhed criminally. Thus, if a minor goes about the
towm, and, pretending to be of age, defrauds many
perfons by taking credit for a confiderable quantity of
goods, and then infilling on his nonage, the perfons in¬
jured cannot recover the value of their goods, but they
may indnfl and punifh him for a common cheai. Per¬
fons conviaed of obtaining money or goods .by falfe
pretences, or of fending threatening letters m older
to extort money or goods, may be punifned with fine
or imprifonment, or by pillory, w'hipping, or tranfpoi-
tation.
CHEBRECHIN, a town of Poland, in the province*
of Ruffia and palatinate of Bellkow. It is feated on
the declivity of a hill, and the river Wierpi waters its
walls, and afterwards falls into the river Bog. The
Jew’s there are very rich. E. Long. 23. 51, N. Lat.
50. 35.
CHECAYA, in Turkiffi affairs, the fecond officer
of the janizaries, who commands them under the 3g3>
and is otherwdfe called protogero.
There is alfo a checaya of the treafury, ftables, kit¬
chen, &c. the word fignifying as much as lieutenant,
or the fecond in any office.
CHECK, or Check-RoII, a roll or book, wherein
are contained the names of fuch perfons as are attend¬
ants and in the pay of the king, or other great perfon-
ages, as their houfehold fervants.
Clerk of the Check in the king's houfehold, has the
check and controlment of the yeomen of the guard,
and all the uffiers belonging to the royal family,, al¬
lowing their abfence or defefts in attendance, or dimi-
niftiincr
CHE [41
nlfiling their wages for the fame, &c. He alfo, by
himfelf or deputy, takes the view of thofe who are to
watch in the court, and has the fetting of the watch,
Clerk of the Check in the royal dock yards, an oni¬
cer who keeps a mufter or regifter of all the men em¬
ployed aboard his majefty’s fhips and veffels, and alfo
of all the artificers and others in the fervice of the na¬
vy at the port where he is fettled.
Check, in falconry, a term ufed of a hawk, when
the forfakes her proper game, to fly at pies, crows,
rooks, or the like, that crofs her in her flight.
CHECKY, in Heraldry, is when the ihield, or a
bordure, &c. is chequered, or divided into chequers
or fquares, in the manner of a chefsboard.
This is one of the mofl noble and moft ancient fi¬
gures ufed in armoury j and a certain author faith,
that it ought to be given to none but great warriors,
in token of their bravery *, for the chefsboard repre-
fents a field of battle j and the pawns placed on both
fides reprefent the foldiers of the two armies, which
move, attack, advance, or retire, according to the will
of the gamefters, who are the generals.
This figure is always compofed of metal and colour.
But feme authors would have it reckoned among the
feveral forts of furs.
CHEEK, in Anatomy, that part of the face fituat-
ed below the eyes on each fide.
Cheeks, a general name among mechanics, for al-
moft all thofe pieces of their machines and inftruments
that are double and perfeftly alike. Thus, the cheeks
of a printing prefs are its two principal pieces : they
are placed perpendicular, and parallel to each other j
ferving to fuftain the three fommers, viz. the head,
flielves, and winter, which bear the fpindle, and other
parts of the machine. See Printing Prefs.
The cheeks of a turner's lathe, are two long pieces
of wood, between which are placed the puppets, which
are either pointed or otherwife, ferving to lupport the
work and the mandrils of the workman. Thefe two
pieces are placed parallel to the horizon, feparated
from one another by the thicknefs of the tail of the
puppets, and joined with tenons to two otner pieces
of wood placed perpendicularly, called the legs of the
lathe.
Cheeks of the glacier's vice, are two pieces of iron
joined parallel at top and bottom; in which are tne
axles, or fpindles, little wheel, cufhions, &c. whereof
the machine is compofed.
The cheeks of a mortar, or the brackets, in artillery,
are made of ftrong planks of wood, bound with thick
plates of iron, and are fixed to the bed by four bolts;
they fife on each fide of the mortar, and ferve to
keep her at what elevation is given her, by the help of
llrong bolts of iron which go through both cheeks,
both under and behind the mortar, betwixt which are
driven quoins of wood 5 thefe bolts are called the brack¬
et bolts, and the bolts which are put one in each end
of the bed, are the traverfe bolts, becaufe with hand.
fpikes the mortar is by thefe traverfed to the right or
left. ... • r*
Cheeks, in Ship-budding, are twm pieces or tim¬
ber, fitted on each fide of the mall at the top, ferv¬
ing to ftrengthen the mails there. The uppermoft
bail oj piece of timber in the beak of a fliip is called
Vox. V. Part II.
7 ] CHE
the cheek. The knees which fallen the beak head to , Caiecfc- :
the fhip are called cheeks ; and the fides of any block,
or the fides of a Ihip’s carriage of a gun, are alfo
called cheeks.
CHEESE, a fort of food prepared of curdled milk
purged from the ferum or whey, and afterwards dried
for ufe.
Cheefe differs in quality according as it is made from
new or fkimmed milk, from the curd which feparates
fpontaneoully upon Handing, or that which is more
fpeedily produced by the addition of runnet. Cieam
alfo affords a kind of cheefe, but quite fat and butyra-
ceous, and which does not keep long. Analyzed che¬
mically, cheefe appears to partake much more of an
animal nature than butter. It is infoluble in every li¬
quid except fpirit of nitre, and caullic alkaline ■iey*
Shaved thin, and properly treated with hot vvater, it
forms a very llrong cement if mixed with quicklime . ^
When prepared with the hot water, it is recommended
in the Swedilh Memoirs to be uied by anglers as a
bait i it may be made into any form, is not foftened
by the cold wTater, and the filhes are fond of it. As
a food, phyficians condemn the too free ufe of cheele.
When new, it is extremely difficult of digellion : when
old, it becomes acrid and hot 5 and, from Dr Perci-
val’s experiments, is evidently of a feptic nature. It
is a common opinion that old cheefe digefts every
thing, yet is left undigelled itlelf j but this is without
any folid foundation. Cheefe made from the milk of
ftieep digefts fooner than that from the milk of cows,
but is lefs nourilhing ; that from the milk of goats
digefts fooner than either, but is alio the leail nou-
rilhing. In general, it is a kind of food fit only for
the laborious, or thofe whofe organs of digeftion are
ftrong- r 1 • j-
Every country has places noted for this commodity .
thus Cheffiire and Gloucefter cheefe are famous in Eng¬
land ; and the Parmefan cheefe is in no lefs repute a-
broad, efpecially in France. I his fort of cheefe is
entirely made of fvveet cow milk : but at Rochefort 111
Languedoc, they make it of ewes milk ; and in other
places it is ufual to add goat or ewes milk in a certain
proportion to that of the cow. There is liken lie a
kind of medicated cheefe made by intimately mixing
the expreffed juice of certain herbs, as fage, baum,
mint, &.C. with the curd before it is falhioned into a
cheefe. The Laplanders make a fort of cheefe of the
milk of their rein deer which is not only of great ler-
vice to them as food, but on many other occafions. L
is a very common thing in thefe climates to have a
limb numbed and frozen with the cold . their ieniv.ciy
for this is the heating an iron red hot, and thrufting it
through the middle of one of thefe cheefes j they catch
wffiat drops out, and with this anoint the limb, which
foon recovers. They are fubjeft alfo to coughs and
difeafes of the lungs, and thefe they cure by the fame
fort of medicine : they boil a large quantity of the
cheefe in the frefli deer’s milk, and drink the decoc¬
tion in large draughts warm feveral times a-day. I hey
make a lefs ftrong decoftion of the fame kind alfo,
wffiic h they ufe as their common drink, for three or
four days together, at feveral times of the year. 101
an account of the different procefies for making cheese,
fee Cheese, Agriculture Index.
CheesE-Reswet. See Galium and Runnet.
3 q CHEGOE,
CHE [41
Chegoe CHEGOE, or Nigua, the Indian name of an in-
fe£l common in Mexico, and alfo found in other hot
countries where it is called pique, is an exceeding fmall
animal, not very unlike a flea, and is bred in the duft.
It fixes upon the feet, and breaking infenfibly the cu¬
ticle, it neflles betwixt that and the true Ikin, which
alfo, unlefs it is immediately taken out, it breaks, and
pierces at laft to the flelh, multiplying with a rapidity
almofl: incredible. It is feldom difeovered until it
pierces the true fldn, when it caufes an intolerable
itching. Thefe infefls, with their aftonifliing multi¬
plication, -would foon depopulate thofe countries, were
it lefs eafy to avoid them, or were the inhabitants lefs
dexterous in getting them out before they begin to
fpread. On the other hand, nature, in order to leflen
the evil, has not only denied them wings, but even
that conformation of the legs and thofe ftrong mufcles
which are given to the flea for leaping. The poor,
however, who are in fome meafure doomed to live in
the duft, and to an habitual negledl of their perfons,
fuffer thefe infe£ts fometimes to multiply fo far as to
make large holes in their flefli, and even to occafion
dangerous wounds.
CHEIRANTHUS, stock-gilliflower, or Wall-
Jlouoer. See Botany Index.
CHEKAO, in Natural Hlftory, the name of an
earth found in many parts of the Ealt Indies, and
fometimes ufed by the Chinefe in their porcelain ma-
nufaftures. It is a hard and ftony earth 5 and the
manner of ufing it is this: they firfl: calcine it in an
open furnace, and then beat it to a fine powder. This
powder they mix with large quantities of water : then
llirring the whole together, they let the coarfer part
fubfide j and pouring off the relt yet thick as cream,
they leave it to fettle, and ufe the matter which is
found at the bottom in form of a foft parte, and will
retain that humidity a long time. This fupplies the
place of the earth called hoaebe, in the making of that
elegant fort of china-ware which is all white, and has
flowers which feem formed by a mere vapour within its
furface. The manner of their ufing it is this: they
firtt make the veffel of the common matter of the ma-
nufaflure \ when this Is almoft dry, they paint upon it
the flowers, or whatever other figures they pleafe, with
a pencil dipt in this preparation of the chekao ; when
this is thoroughly dry, they cover the whole veffel
with the varnifh in the common way, and bake it as
ulual. The confequence is, that the whole is white :
but the body of the veffel, the figures, and the varnifh,
being three different fubftances, each has its own par¬
ticular white } and the flowers being painted in the
fineft white of all, are diftindlly feen through the var¬
nifh upon the veffel, and feem as if traced by a vapour
only. The hoache does this as well as the chekao j
and has befides this the quality of ferving for making
the porcelain ware either alone, or in the place of ka¬
olin : the chekao has not this property, nor any other
fubftance befides this hoache, which appears to be the
fame with our fteatites or foap-rock.
CHE.KE, Sir John, a celebrated ftatefman, gram¬
marian, and divine, of an ancient family in the ifle of
Wight, was born at Cambridge in the year 1514, and
educated at St John’s college in that univerfity j where,
after taking his degrees in arts, he was firft chofen
Greek lecturer, and in 1540 profefl.br -of that lan-
I
8 ] CHE
guage, with a ftipend of 40I. a-year. In this ftation Cheke,
he was principally inftrumental in reforming the pro- Chc-kyang.
nunciation of the Greek language, which, having been
much negledled, was imperfectly underftood. About
the year 1543 he was incorporated mafter of arts at
Oxford, where, we are told, he had rtudied for fome
time. In the following year he was fent to the court
of King Henry VIII. and appointed tutor for the La¬
tin language, jointly wdth Sir Anthony Cooke, to
Prince Edward, about which time he was made canon
of the college newly founded in Oxford : wherefore he
muft have now been in orders. On the acceflion of
his royal pupil to the crown, Mr Cheke was firft re¬
warded with a penfion of 100 merks, and afterwards
obtained feveral confiderable grants from the crown.
In 1550 he was made chief gentleman of the privy-
chamber, and was knighted the following year; in
1552, chamberlain of the exchequer for life ; in 1553,
clerk of the council j and foon after fecretary of ftate
and privy-councillor. But thefe honours were of ftiort
duration, tlaving concurred in the meafures of the
duke of Northumberland for fettling the crown on the
unfortunate Jane Grey, and a&ed as her fecretary
during the nine days of her reign, on the acceflion of
Queen Mary, Sir John Cheke was fent to the tower,
and ftript of the greatert part of his poffeffions. In.
September 1554 he obtained his liberty, and a licenfe
from her majefty to travel abroad. Pie went firft to
Bafil, thence to Italy, and afterwards returned to
Strafburg, where he was reduced to the neceflity of
reading Greek leftures for lubfiftence. In 15^6 he
fet out in an evil hour to meet his wife at Bruffels :
but, before he reached that city, he was feized by or¬
der of King Philip II. hoodwinked, and thrown into
a waggon ; and thus ignominioufly conduced to a
fliip, which brought him to the tower of London.
He foon found that religion was the caufe of his im-
prifonment; for he was immediately vifited by two
Romifli priefts, who pioufly endeavoured to convert
him, but without fuccefs. However, he was at laft
vifited by Fleckenham j who told him from the queen,
that he muft either comply or burn. This powerful
argument had the defired effetff ; and Sir John Cheke
accordingly complied in form, and his lands, upon cer¬
tain conditions, were reftored ; but his remorfe foon
put an end to his life. He died in September 1557,
at the houfe of his friend Mr Peter Ofborne in Wood-
ftreet, London, and was buried in St Alban’s church.
He left three fons, the eldeft of whom, Henry, was
knighted by Queen Elizabeth. He wrote 1. A Latin
tranflation of two of St Chryfoftom’s homilies. Lond.
1543, qto. 2. The PJurt ot Sedition. Lond. 1549,
1576, 1641. 3. Latin Tranflation of the Englifli Com-
rimnion Service. Printed among Bucer’s opufcula.
4. Depronuneiatione Greeca. Bafil, 1555, 8vo. 5. Se¬
veral letters publifhed in his life by Strype ; and a
great number of other books.
CHE-KYANG, or Tche-kianG, a maritime pro¬
vince of China, and one of the moil; confiderable in
the empire •, is bounded on the fouth by Fo-kien ; on
the north and weft by Kiang-nan and Kiangfi ; and
on the eaft by the fea. The air is pure and healthful,
and the foil fertile, being watered by a number of ri¬
vers and canals, as well as Iprings and lakes. The
chief produce is filk ) a vaft quantity of which is cul¬
tivated
CHE [ 419 ] CHE
Che-kyang. tivated here, and for which the whole country is cover-
y—cd with mulberry trees. Thefe are purpofely checked
in their growth by the natives, experience having
taught them, that the leaves of the fmalleft trees pro¬
duce the beft filk. The fluffs made in this province,
which are embroidered with gold and filver, are rec¬
koned the beft in the empire j and notwithftanding a
vaft exportation to the Japan and Philippine iflands, as
well as to every part of China, and to Europe, fuch an
abundance is left in the province, that a complete fuit
of filk may be bought here as cheap as one of the
coarfeft wToollen in France.
This province is alfo remarkable for a particular fpe-
cies of mufhrooms, which is exported to every part of
the empire. They are pickled, and then dried ; W'hen
they will keep good for a whole year. When ufed
they muft be foaked in water, which renders them as
frelh as at firft. Here alfo the tallow tree is met
with ; and the province affords excellent hams, and
thofe fmall gold fifties with which the ponds are ufually
flocked.
Che-kyang contains 11 cities of the fitft clafs, 72
of the third, and 18 fortreffes, which, in Europe, would
be accounted large cities. The principal of thefe are,
I. Hang-tcheou-fou, the metropolis, accounted by the
Chinefe to be the paradife of the earth. It is four
leagues in circumference, exclufive of the fuburbs; and
the number of its inhabitants are computed at more
than a million, and 10,000 workmen are fuppofed to
be employed within its walls in manufa&uring of filk.
Its principal beauty is a fmall lake, clofe to the walls
on the weftern fide, the water of which is pure and
limpid, and the banks almoft everywhere covered with
flowers. Its banks are likewife adorned with halls and
open galleries fupported by pillars, and paved with
large flag ftones for the convenience of thofe who are
fond of walking j and the lake itfelfis interfered with
caufeways cafed with cut ftone, openings covered with
bridges being left in them for the paffage of boats. In
the middle are two iflands with a temple and feveral
pleafure houfes, and the emperor has a fmall palace in
the neighbourhood. The city is garrifoned by 3000
Chinefe and as many Tartars, and has under its jurif-
didlion leven cities of the third clafs. 2. Hou-tcheou-
fou is alfo fituated on a lake, and manufa£l:ures an in¬
credible quantity of filk, infomuch, that the tribute
of a city under its jurifdi£lion amounts to more than
qoo,ooo ounces of filver. 3. Ning-po-fou, by Euro¬
peans called Liampo, is an excellent port, opponte to
Japan. Eighteen or twenty leagues from it is an
ifland called Tcheou-chan, where the Englilh firft land¬
ed on their arrival at China. 4. Ning-po is remarK-
able for the filk manufactured there, which is much
efteemed in foreign countries, efpecially Japan, W’here
it is exchanged for gold, filver, and copper. 5. Chao-
hing-fou, fituated in an extenfive and fertile plain, is re¬
markable for a tomb about half a league diftant, which
is faid to be that of Yu. The people of this province
are faid to be the moft verfed in chicanery of any in
China. 6. Tchu-tcheou-fou, remarkable for having
in its neighbourhood pines of an extraordinary fize,
capable of containing 40 men in their trunks. 1 he
inhabitants are ingenious, polite, and courteous to Chelidonias
ftrangers, but very fuperftitious. n ^ ■„
CHELIDONIAS, according to Pliny, an anniver-. te‘”‘ ' »
fary wind, blowing at the appearance of the fwallows j
otherwife the Favonius, or Zephyrus.
CHELIDONIUM, celandine, and horned or
prickly poppy. See Botany Index.
CHELIDONIUS lapis, in NaturalHi/lory, a ftone
faid by the ancients to be found in the ftomachs of
young fwallovvs, and greatly efteemed for its virtues
in the falling ficknefs.
CHELM, a town of Poland, capital of a palatinate
of the fame name. It is fituated in the province of
Red Ruflia. E. Long. 23. 30. N. Lat. 51. 25.
CHELMSFORD, the county town of Effex, fi¬
tuated on the river Chelmer, in E. Long. o. 30.
N. Lat. 51.40. It fends two members to parlia¬
ment.
CHELONE. See Botany Index.
CHELSEA, a fine village fituated on the northern
bank of the river Thames, a mile weft ward of Weft-
minfter, remarkable for a magnificent hofpital of in¬
valids and old decrepid foldiers; and a pleafure houfe,
called Ranelagh, to which a great deal of fine com¬
pany refort in fummer j and a noble botanic garden
belonging to the company of apothecaries. The roy¬
al hofpital of invalids was begun by Charles II. car¬
ried on by James II. and finilhed by King William.
It confifts of a vaft range of buildings, that form three
large fquares, in wdiich there is an uncommon air of
neatnefs and elegance obferved. It is under the di-
reftion of commiflioners, who confift generally of the
officers of ftate and of war. There is a governor with
500I. falary, a lieutenant-governor with 400I. and a
major with 250I. befides inferior officers, ferjeants,
corporals, and drums, vdth above 400 mcn> who all
do garrifon duty j and there are above 10,000 out-
penfioners who receive an annuity of 7]. 12s. 6d.
each ; all which expence is defrayed by a poundage
deduced from the army, deficiencies being made good
by parliament.—The botanic garden is very extenfive,
enriched with a vaft variety of domeftic and exotic
plants, the original flock of which was given to the
apothecaries of London by Sir Hans Sloane.—At Ra¬
nelagh garden and amphitheatre, the entertainment is
a fine band of mufic, with an organ and fome of the
beft voices: and the regale is tea and coffee.
CHELTENHAM, or Chiltenham, a market
town of Gloucefterfhire, feven miles north-eaft of
Gloucefter. W. Long. 2. 10. N. Lat. 51. 50. It is
chiefly remarkable for its mineral waters, of the fame
kind with thofe of Scarborough. See Scarbo¬
rough.
CHEMISE, in Fortification, the wall with which
a baftion, or any other bulwark of earth, is lined for
its greater fupport and ftrength : or it is the folidity of
the wall from the talus to the ftone row.
Fire Chemise, a piece of linen cloth, fteeped in a
compofition of oil of petrol, camphor, and other com-
buftible matters, ufed at fea to fet fire to an enemy’s
veffel.
3G2
CHEMISTRY.
[ 420 ]
C H E M I
INTRODUCTION.
i /CHEMISTRY is defined by Dr Black, to be “ the
Definition. ftudy of the effects produced by heat and by
mixture, in all bodies, or mixtures of bodies, natural
or artificial, with a view to the improvement of the
arts, and the knowledge of nature or, according to
the definition propofed by the learned editor of his lec¬
tures, “ chemilfry is the ftudy of the effedts of heat
and mixture, with the view of difcovering their gene¬
ral and fubordinate laws, and of improving the ufeful
arts.”
Fourcroy has defined “ chemiftry to be that fcience
which teaches the knowledge of the intimate and reci¬
procal a&ion of all the bodies in nature on one ano¬
ther.” To this definition it has been objected, that it
requires much explanation, that the terms reciprocal
and intimate adtion not being readily underftood, would
need new definitions to explain them, and that it em¬
braces more than what ftridlly belongs to the fcience
of chemiftry. When motion is communicated, or ta¬
ken away by the collifion of different bodies, the ac¬
tion between thefe bodies is intimate and reciprocal $
but the ftudy of this adtion belongs to mechanics, and
not to chemical fcience.
Perhaps no definition of chemiftry has yet been gi¬
ven which is of fufhcient logical precifion to be entire¬
ly free from objedlion. The objedf of chemiftry,
however, admits of no ambiguity. It is the province
of natural hiftory to arrange and diftribute natural bo¬
dies into claffes and orders, each being accurately cha-
radterized, fo that the objedfs which it includes may
be readily recognized and diftinguifhed by eafy marks
of reference. Mechanical fcience is employed about
the external properties of bodies, and their effedls on
each other, the force and meafure of which is fubjedt
to calculation •, but it is the objedt of chemiftry to dif-
cover the component parts of bodies, to examine the
properties and ufes of the combinations formed, either
naturally or artificially, from thefe fimple fubftances,
and to obferve and trace the laws by which thefe com¬
binations take place.
Sect. I. Divifion of Natural Knowledge.
Variety of When we confider the immenfe and endlefs variety
objedls im- 0f 0bjefts which prefent themfelves to the eye, it muft
menic' appear, at firft fight, impoflible to acquire even a ge¬
neral knowledge of their qualities and properties. And,
indeed, the longeft life, with the moft vigorous mind and
the moft indefatigable induftry, would be greatly in¬
adequate to the talk of examining every individual ob-
- jedl. Hence it is, by a law of the human mind, that
we arrange the objedts of our inveftigations into certain
claffes, the individuals of which are found to poffefs
certain general properties. Thefe are again fubdivid-
ed into other claffes with additional diferiminative
marks ; and thefe laft are ftill farther fubdivided, till
v/e arrive at the individual ^ and, if the arrangement
S T R Y.
be corredl, this muft poffefs all the charadleriftic marks
of reference to the general and fubordinate divifions of
that clafs of objedts to which it belongs. In this w>ay
the mind is aided in its inveftigations, and the commu¬
nication of knowledge is facilitated and improved. ^
Thus it is the province of natural hiftory to arrange Natural
the objedls which come under our obiervation, and to
deferibe them with fuch precifion and accuracy as they
may be eafily diftinguilhed from each other. It may
be confidered as a deferiptive view of the material
world in a ftate of reft or inadtion, without taking in¬
to account the motions or mutual adiion of bodies on
each other. It is the firft fuccefsful ftep in the pro-
grefs of knowledge. 4
But the operations of nature are feldom at reft. Natural
Change lucceeds change, new combinations are form-1 1 oiopuj-
ed and new produdlions make their appearance. T he
primary planets revolve round the fun as their centre j
the lecondary planets, or the moons, attradled by the
primary, perlorm fimilar revolutions; the air of the
atmofphere preffes on the lurface of the earth with a
certain force ; a ftone, w-hen unfupported, falls to the
earth in a courfe diredted towards its centre j water
deprived of a certain portion of heat becomes folid,
and appears in the form ol ice } when combined with a
greater portion of heat than w hat is neceffary to retain
it in the fluid ftate, it affumes the form of vapour, af-
cends into the atmofphere, is there by certain procel-
fes, robbed of its heat, and re-appears in the form of
rain ; or, when a greater portion is abftradled, takes
that of fnow or hail, and falls to the earth. A feed
is put into the ground ; and it heat, air, and moifture
be applied, it germinates and fprings up } and, with
the addition of light, if the operation of the lame
agents be continued, it becomes a new plant, puts
forth leaves and flow:ers, and produces feeds fimilar to
that from which it fprung. 5
Now to determine what are thefe changes, to ob- Phyfics.
ferve the law^s by which fuch changes are effe&ed, and
to afeertain the meafure and quantity of the effect pro¬
duced, belong to that department of knowledge which
is included under the general term natural philofophy
or phyfics. But of thefe changes or motions, fome are
obvious and palpable, others entirely elude our fenfes.
We fee a ftone defeend to the earth ; and experience
informs us, that it falls with a force in a certain pro¬
portion to its weight and the height from which it fell.
The peculiar change or motion which takes place when
water affumes the folid form, when a fluid undergoes
the procefs of fermentation, or when a combuftible bo¬
dy is burned, is altogether imperceptible. Theie mo¬
tions are too minute to be recognized. The effedl is
produced before w^e can difeover the change. ^
Thus natural philofophy divides itfelf into two great Cliemiftry,
branches. The obje£ls of the JlrJl are the fenfible
changes or motions wdrich are obierved in the material,
world 5 and the confideration of thefe objefts is, pro¬
perly fpeaking, natural philofophy or phyfics. The
fecond great branch which is employed in difcovering
the
C H E M I
Introduc- tlie laws, and apnrerht’ng tVie effefts, of the infenfible
bon. motions of bodio», conllitutes the fcience of chemi-
^ v ftry (a).
Sect. II. Of the ObjeSis and Importance of Chemi/Iry.
The importance and extenfive utility of this fcience
muft appear obvious to thofe who have at all confider-
ed the fubjeft. But for the fake of thofe who are yet
unacquainted with it, we (hall take a general view of
7 the obje&s which it embraces, and the advantages to
Ufefulin be derived from the ftudy of chemiftry, whether in ex-
natural'11^ plaining many of the flriking operations of nature, or
phenome- in improving the arts of life.
naj The moft wonderful effedls, after frequent repeti¬
tion, become familiar, and ceafe to produce any emo¬
tion in the mind. It is on this account that many of
the moft ftriking appearances of nature pafs unheeded
as trifling occurrences, and are unnoticed by common
obfervers. Had we been always accuftomed to the ri¬
gour of winter, and never knorvn the genial warmth
of fpring, or experienced the ripening ftrmmer’s heat,
the aftonilhing changes effefted by the return of thefe.
feafons could not fail to fill us with admiration.
Thefe changes are of fuch univerfal influence, that
they are limited to no department of nature. Their
beneficial effefts are felt in the inanimate, as well as in
the animated creation. The fame power which is feen
in the gay profufion of the vegetable tribes, rettores
to a new exiftence myriads of animals, whofe vital
funftions had been fufpended. The air, the earth, the
waters, fwarm with life.
The principal agent in the produiftion of thefe chan¬
ges is heat; an agent, the moft powerful and irrefifti-
ble in its operations, unlimited in its effefts, and ex¬
tenfive in its importance and utility. This agent,
therefore, afting fo powerfully in chemical operations,
becomes an effential objeft of chemical fcience. Clofe-
ly connefted with heat is light, which is alfo a power¬
ful agent in many of the proceffes of nature. This,
too, is neceffarily a fubjeft of chemical inveftigation,
not lefs curious and interefting. Such, indeed, is the
univerfal importance of light and heat in all the pro-
celfes of nature, that no change takes place, no new
combination is formed, or new produft makes its ap¬
pearance, in which the one or the other, or both, are
not evolved or abforbed.
In the knowledge of the conftitution of the atmo-
fphere, in inveftigating the changes to which it is fub-
jeft, the variations of temperature, winds, dew, rain,
hail and fnow, chemiftry is our principal, our only fa-
tisfadlory guide. Thefe remarkable changes are to be
confidered as immenfe chemical operations, and can
only be explained by chemical laws.
To man in ®ut ^ ^ infinite variety of objefts
the ftudy of from which man muft derive the means of his comlort,
his happinefs and his luxuries, the means, it might be
added, of his very exiftence, chemiftry affords him the
moft important aid. Whether his refearches- be car¬
ried into the mineral, the vegetable, or the animal
S T R Y. 421
kingdoms, the ftudy and cultivation of chemical fci- Introduc-
ence become effentially requifite for the fuccefsful pro- tlon‘ ,
grefs of his inveftigations. ^
Of the importance of chemiftry to the mineralogift, Minerals,
the limited and unfettled ftate of this fcience previous
to the improvements of modern chemiftry, is a convin¬
cing proof. In miner ftogy, the knowledge of che¬
miftry is not only neceffary in detedling and difcrimi-
nating the various fubftances of which the globe which
we inhabit is compofed, in feparating and purifying
thefe fubftances, but alfo in preparing and accommo¬
dating them to the numerous purpofes of life. IO
Of the knowledge which we poffefs of the vegeta- Vegetables
ble kingdom, chemiftry furnifhes a very large (hare.
It is from this fcience that we derive the means of
tracing the progrefs of vegetation, of illuftrating the
peculiar funftions of plants, and difcovering the com¬
pounds which are formed from a few fimple principles,
the nature and properties of thefe compounds, and their
relative proportions, which exhibit an immenfe variety
of new produftions, many of them of the utmoft im¬
portance to man, on account of their nutritious quali¬
ties, or indiredlly ufeful to him by affording nourifh-
ment to thofe animals which he employs as food.
Hence the advantage of applying chemical knowledge
to agriculture, in determining the nature of the foil fit
for the reception of plants, their proper food, and the
mode of fupplying it in the preparation of manures.
With thefe objedfs in view, chemirtry holds out incal¬
culable advantages in the improvement of many de¬
partments of agriculture and rural economy, many of
which, from the rapid and fuccefsful progrefs of the
fcience, there is room to hope, may be foon ob¬
tained. Ir
Nor is the application of chemical fcience to the Animals,
economy of animals lefs limited in its importance and
utility. It not only contributes to the means of de-
compofing animal matters, and of exhibiting and ex¬
amining leparately the conftituent parts of animal fub¬
ftances ; but alfo ferves to explain in fome meafure
many of the effential fundlions of the living animal
body : fuch are digeftion, refpiration, fecretion, which,
fo far as matter is concerned, and the changes which
it undergoes, are to be confidered as true chemical
proceffes, and can only be inveftigated by chemical
principles. But it is here neceffary to obferve, that
the fun&ions of the living vegetable or animal, cannot
be wholly accounted for from the nature of chemical
aflion, without taking into confideration the exiftence
of the vital principle, which counterafts and regulates
the operation of chemical agents, aids and promotes
the beneficial effefts of thofe that are ufeful to its
health and growth, and refills and dettroys thofe that
are hurtful. T7t
The utility of chemiftry in medicine is too obvious Medicine,
to require much illuftration. Such, indeed, is its im¬
portance that it is now univerfally received and ac¬
knowledged as one of the effential branches of medical
education. So far as the principles of chemiftry can
be applied in inveftigating the nature of the fundlions
of
(a) For this view of the divifion of natural knowledge, we are indebted to the Introduflory Lcflures of Pro--
feffor Robifon of Edinburgh.
422
C H E M I
13
The arts.
Introduc- of the animal body in a ftate of health, or can be em-
tl0n- ployed in accounting for the irregular a£Hon of thefe
powers, whether exceflive or deficient, which indicates
a deranged ftate of the funftions, and conftitutes dif-
eafe, its relation to medicine muft be confidered clofe
and intimate. But the medical art comprehends more
than a bare knowledge of the ftruflure and functions
of the animal body. It alfo includes an accurate
knowledge of the fubftances employed as remedies, of
their nature and properties as fimple fubltances, and
their new qualities and effe&s under new combina¬
tions. This knowledge can only be acquired by the
lludy of chemiftry, which is indebted to medicine for
fome part of its progrefs as an art, in the difcoveries
which w'ere accidentally made by the rude and un¬
certain experiments of medical pradlitioners in the
early ages, to afcertain the fenfible qualities and falu-
tary effedls of the remedies which they employed.
Chemiftry, by its rapid progrefs in modern times, has
amply repaid thefe advantages, and in the hands of
the intelligent and accurate obferver, has greatly con¬
tributed to give more rational and fimple views of me¬
dical fcience.
In confidering the application of chemifiry to the
improvement of the arts of civilized life, a wide field
of contemplation opens to our view. So extenfive
indeed are its influence and importance, that in
moil of the arts, many of the proceffes, in fome ail
that are employed, depend on chemical principles.
Barely to mention fome of thefe arts will afford am¬
ple illuftration of its extenfive utility. In the art of ex-
trafting metals from their ores, in purifying and com¬
bining them with each other, and in forming inflru-
ments and utenfils, whether for ufeful or ornamental
purpofes, almoft all the proceffes are purely chemical.
The effential improvements which modern chemiftry
has introduced in the manufa£ture of glafs and porce¬
lain fhew its importance and utility in thefe arts. Nor
has it contributed lefs by the application of its princi¬
ples to the arts of tanning, foapmaking, dyeing, and
bleaching. All the procefteS in baking, brewing, and
diftilling, moft of the culinary arts, and many others
in domeftic economy, are chemical operations. In
fhort, wherever, in any of the proceffes of nature or of
art, the addition or the abftraftion of heat takes place j
wherever fubftances in combination are to be decom-
pofed or feparated j wdierever the union of fimple fub-
ftances is wanted, and new compounds are formed,
there effefts are produced which can only be explain¬
ed and underftood by chemical principles.
From this view of the extenfive application of che¬
mical fcience in explaining many of the operations of
nature, and in elucidating many of the proceffes of the
arts of life, thofe who have not confidered the objefts
which it embraces will be enabled to judge of the im¬
portance of this ftudy.
But however much we may be interefted in obferv-
ing and admiring the changes and effedls produced by
-chemical aftion, if we extend our views, and confider
S T R Y.
chemiftry as a fcience, as the fubjeft of philofophical Introdue-
inveftigation, it will command a greater (hare of our ^ ,
attention and ftudy. And perhaps thcie is no ftudy
better calculated to promote and encourage that ge-As a fci-
nerous and ardent love of truth which confers dignity ence.
and fuperiority on thofe who fuccefsfully purfue it.
Chemiftry is not one of thofe barren difcuflions which
terminate in the difcovery of fome fpeculative truth,
which is merely gratifying to curiofity. In this
view, indeed, no fcience holds out more interefting
fubje&s of refearch, in the fingular and furprifing
changes which everywhere prefent themielves. And
it is furely no fmall recommendation to the ftudy of
chemiftry, that while we ftore the mind with intereft¬
ing truths, we add fomething to the flock of human
knowledge, which is perhaps immediately applicable
to fome of the moft important purpofes of life. . 1 hus
might the value of the fa&s and difcoveries in any
fcience be fairly eftimated, in proportion as they en¬
large our refources by their ufeful application, and win¬
tered and gratify the mind as fubjedls of curious fpe-
culation. From both thefe confiderations the whole
range of chemical fa£ts derives the higheft value ; and
from thefe confiderations chemiftry is entitled to a di-
ftinguiflied place among the fciences. _ I5
Chemiftry has yet a higher claim to our attention in con-
and confideration, as it affords us fome of the moft templating
ftriking proofs of the wifdom and beneficence of the works
Creator of the univerfe. A machine conftru&ed byu 'u
human art is admired according to the fimplicity of its
contrivance, and the extent of its uiefulnefs j and in
proportion to the perfection which we dilcover, we^
eftimate the ingenuity and excellence of the plan of
the artift. But the works of man, with all his boafted
{kill and attainments, fink into nothing when brought
into comparifon with the works of nature. In our
examination of the former, every ftep of our progrefs
is obfcured with defeCls : in contemplating the latter,
we behold perfeClion rife on perfection, and new won¬
ders meet our view. By the aid which wje derive from
chemiftry we are enabled to take 3 minuter furvey of
the great fyftem of the univerfe. And fo far as our
limited powers can comprehend it, the whole is nicely
balanced and adjufted, and all its changes tend to the
moft beneficial purpofes. What on a fuperficial view
were feeming imperfeCtions and defeCts, a clofer infpec-
tion points out to be real excellencies. In all the
changes which are conftantly going forward, the more
clofely we obferve and examine them, the more we
{hall admire the fimple means by which they are ac-
compliftied, and the intelligent defign and perfeCt
wifdom which are difplayed in the beneficial ends to
which they are direCted.
Sect. III. Hijlory of Chemijlry.
The word chemiftry, which is fuppofed to have
been of Egyptian origin, feems to have been firft ufed
in a very extenfive fenfe (b). It appears to have in¬
cluded
(b) According to fome it is derived from the word kcma, which was fuppofed to be a book of feciets given
to the women by the demons. Others derive it from Cham the fon of Noah, from whom Egypt took the
name of Chemie. or Chamie. Sometimes the origin of the word is afcribed to Chemmis, a king of the Egyptians j
and
an art
C H E M
eluded all the knowledge which the ancients poffeffed
of natural objefts. It was afterwards more limited
in its fignification, and folely confined to the art of
working metals. The great importance which the
antients attached to this art was probably the caufe of
this limitation. Such indeed was its importance, that
thofe who were fuppofed to have difeovered or im¬
proved it, were regarded by mankind as their greateft
benefaftors. They were raifed above the level of the
human race, were deemed worthy of being enrolled
among the gods; and temples and ftatues were confe-
crated to their honour.
It is not neceffary minutely to trace the hiftory of
chemillry to the remote periods of antiquity, or labour
to prove its origin to be coeval with the early ages of
the world. Man indeed could not exill: long without
fome knowledge of chemical procefles ; and as he im¬
proved in civilization and accurate obfervation, this
knowledge muft have been improved and extended.
Tubal-Cain, who is mentioned in the facred Scriptures,
as a worker in metals, and is fuppofed to have given
rife to the fabulous itory of Vulcan, in antient mytho-
j5 logy and poetry, is confidered by fome as the firfl
Chemi'try chemift whofe name has been tranfmitted to the pre-
exiftal as fent time. But although the working of metals, and
other chemical arts, were known in the early ages of
the wmrld •, and among the Egyptians, Greeks, and
Romans, many of the arts dependent on chemillry had
reached fome degree of perfeftion ; yet this knowledge
mull be regarded as confifting only of a number of
fcattered, unconne£led fadls, which deferve not to be
dignified with the name of fcience. A carpenter may
ereft a piece of machinery, arranged and conltrudled
exaftly limilar to what he has feen, without the know¬
ledge of a fingle principle of its conftru6tion ; but the
man of fcience, wTho can neither handle the axe nor the
chiflel, obferves and eftimates the power and operation
of all its parts, and determines the general effeft of the
whole machine.
Nor will it afford us much inftruflion to purfue the
fuppofed hillory of chemiltry, even to a later period.
Mofes, who is faid to have been Ikilled in all the
wifdom of the Egyptians, has been ranked among the
number of the firft chemifts 5 and as a proof of his
knowledge of chemiftry, the means he employed of
dilfolving the golden calf made by the Ifraelites, to
render it potable, are adduced. It is faid, that Demo¬
critus, of all the Greeks wTho travelled into Egypt to
acquire knowledge, was alone admitted into their my-
among the lleries. According to Diodorus Siculus, the art of
Egypna s, chemillry had made very confiderable progrefs among
the Egyptians. The knowledge of their priells is
fuppofed to have confifled chiefly of chemical proceffes.
They xvere acquainted, it is faid, with the preparation
of many medicines, perfumes, plaflers, and foaps $ they
ufed burnt alhes as cauftic fubllances j they fabricated
bricks, glafs, porcelain j they painted on glafs, and
pradlifed the art of gilding with filver and gold. They
extradled natron or foda from the mud of the Nile.
*7
I S T R Y. 423
They prepared alum, fea-falt, and fal ammoniac ; and Introduc-
befides working in gold and copper, they poffdfed tIon-
many other proceffes in metallurgy. The extradlion
of oils, and the preparation of wine and vinegar, were
W'ell known ; and they were alfo acquainted with the
art of dying filk by means of mordants. xS
Fewer traces of chemillry are found among theGreeks>
Greeks, although they derived the knowledge of many
of their arts from Egypt. The ancient philofophers of
Greece, as Pythagoras, Thales, and Plato, were more
devoted to the cultivation of mathematical and aftro-
nomical knowledge, than the phyfical fcicnces. Some
chemical arts, however, were not unknown to this
people. The alloy of metals formed at Corinth, has
been much celebrated. Cinnabar was employed in
fome parts of Greece. Tychius knew’ the art of tan¬
ning leather j Plato has deferibed the procefs of filtra¬
tion •, Hippocrates was acquainted with that of calci¬
nation ; Galen fpeaks of dillillation per defeenfum, and
the word etnbic is mentioned by Diofcorides a long
time before the Arabic particle al was prefixed to it.
According to Athenaeus, there wTas a manufactory of
glafs eftablilhed at Lefbos. Democritus of Abdera pre¬
pared and examined the juices of plants : Ariltotle
and Theophraltus treated of Hones and of metals. it)
The Phoenicians are fpoken of as being acquainted cen^c
with the making of glafs, and the celebrated Tyriananfs
purple was found among this people. They were alfo
fkilled in the working of metals and other mineral fub-
ftances. The Perfians are faid firft to have diftinguifti-
ed the metals by the names of the planets, which they
retained for many centuries. 20
Among the Chinefe, if we may believe their hifto-Chinefe*.
rians, many chemical arts wTere known from the earlieft
ages : they were acquainted with nitre, borax, alum,
gunpowder, verdigris, mercurial ointments, fulphur,
and colouring matters 5 nor w'ere the arts of dying
linen and filk, paper-making, manufacturing of pottery
and porcelain, unknown. They were fkilled in the
art of alloying metals, and in the working of ivory
and of horn. From the early knowledge which the
Chinefe poffeffed of thefe arts, they have been fuppofed
by fome to have been a colony from Egypt. 2I
The w'ars in which the Romans were almoft con-Romans,
ftantly engaged, and the fpirit which prompted them
to military affairs, gave them neither time nor talle to
cultivate and improve the arts of peace. Chemiftry,
therefore, appears to have been little known among
that people. Petronius indeed fpeaks of malleable
glafs, w^hich was prefented to Caefar j and the fame,
or a fimilar faCl, is mentioned by Pliny with regard to
Tiberius. But this art, it appears, was long known
before the time of the Romans.
To us it may appear fomewhat lingular, that che¬
miftry, now of fuch univerfal importance to mankind,
fhould be indebted, in fome meafure, for its origin as
an art, and for fome part of its progrefs, to one of the
lefs noble or generous of the human pafiions. Yet, in
its early dawn, it was cultivated by men who were in-
ftigated
and fometimes to the Greek word %vy.os, which fignifies liquid, becaufe the art was at firft applied in the pre¬
paration of liquids j and fometimes to the Greek verb “ to pour out,” becaufe chemiftry is the art of fufing
metals.
424 C H E M I
Introduc- {ligated by avarice to profecute and ftudy it. About
tio"* the 10th century, or perhaps earlier, a fet of men
v ' arofe, and continued to flouriih till the i6th, who af-
22 fumed by way of diftinftion, the name of alchemijls.
The alche- that is, the chemifts, becaufe they confidered themfelves,
m^5' on account of the knowledge they pofleffed, more
highly favoured than the reft of mankind. It was
natural enough for men "who obferved the remark¬
able chianges produced by chemical aftion, to be
ftruck with the effefts ; and overlooking the varia¬
tions and differences in the refults of their opera¬
tions, which were the , confequences of partial or
inaccurate obfervation, to flatter themfelves that their
porver over the fubftances on which they operated,
was only limited by their wifhes. Hence, perhaps,
originated all the extravagances and follies, fimilar in¬
deed to thofe of fpeculators and proje£lors of every
age, with wThich the hiftory and works of the alche-
•miftical writers are filled. Many of the alchemifts, it
is not improbable, wrere the dupes of their o\vn igno¬
rance and credulity ; but many more, there is little
doubt, took advantage of the ignorance and barbarity
which prevailed in the dark ages, during which period
they chiefly flourifhed, and impofed on the weaknefs
and credulity of mankind.
It was one of the firft principles among the alche¬
mifts, that all metals are compofed of the fame, in¬
gredients, or, that the fubftances which enter into
the compofition of gold, are found in all metals, but
mixed with many impurities, from which, by certain
proceffes, it might be freed. The great, the conftant
objefl of all their labours and refearches was the dif-
covery of a fubftance poffeffed of the wonderful pro¬
perty of converting the bafer metals into gold, which,
on account of its fcarcity and durability, is more
valued and efteemed than the other metals, which are
23 more abundant, and generally more ufeful. This ce-
Philofo- lebrated fubftance was denominated the philojopher'1 s
pliers ftone.ftone, and thofe who were fo Angularly fortunate as to
accompliftr this great difcovery, or thofe to whom it
was imparted by others, wrere regarded, as might na¬
turally be expetted, as the peculiar favourites of
heaven. When they w7ere in poffeflion of this grand
fecret, they were ranked among the higheft order of
alchemifts, and then affumed the name of adepts ; and
thus initiated, they profeffed themfelves mafters of the
enviable fecret of tranfmuting or changing metals of
inferior value, into gold.
But the adepts never feem to have thought of en¬
riching themfelves by their great difcoveries. 1 hey
were too generous to monopolize the W’ealth of the
world. They accordingly offered their fervices to
others, and liberally propofed to communicate the
fruit of their labours for a moderate reward. The
ambitious man to procure riches, that he might in-
creafe his power, and the opulent man to add to his
wealth, eagerly fought after, employed, and encouraged
them in the profecution of their extravagant fchemes.
They were therefore kept in the pay of princes, to
fill and repair their exhaufted treafures, and of great
men who afpired after boundlefs wealth. Thefe flat¬
tering hopes, it may well be fuppofed, were never re¬
alized. The rich profpeft fled before them, and the
golden prize which they often fuppofed was juft within
i-heir reach, eluded their eager grafp. The magni-
S T R Y.
tude of the plan, however, fired the Imagination, Introduc.
and produced fomething like conviction in the mind,
of the poflibility, and even certainty, of obtaining
the objeCl of all their wifties and all their labours. W ith
unabating ardour, with unexampled aftiduity, they pur-
fued their refearches, perfuading themfelves and their
employers, that they were on the point of being loon
in poffeflion of unlimited wealth. < ,
But the alchemifts beholding man by anticipation
poffeffed of immenfe riches, faw that fomething more
was requifite, that he might be fecured in the unin¬
terrupted enjoyment of them. Experience fatally taught
them, that the feeble frame of man was liable to the
pains and languor of difeafe} that gold and filter
could neither prevent the fit of a fever, nor give to the
poffeffor the bleffings of conftant health. Thus ano¬
ther moft defirable objeft was held up to view, and
iner mon ucmauit — -r „ - . 24
deluded their diftempered minds into the ialle hope or Univerfal
attaining it. This was the famous panacea, or urn- medicine,
verfal medicine, which was to cure all difeafes j and ^
not only to cure, but abfolutely to prevent their oc¬
currence. Thus fortunate in the enjoyment of vaft
riches } thus blefled with unbroken health, the defires
of man were yet unfatisfied. Another feeming evil
ftill remained, which was naturally to be dreaded as
the deftroyer of this fancied feene of apparently per-
feft felicity. The melancholy refleftion, that it was
limited by the fhort fpan of human life, roufed the al¬
chemifts again into exertion, and produced new efforts
of ingenuity in their labours, to fecure. to man. ex¬
emption from the common lot of mortality. In ima¬
gination they had difeovered the means of prolonging
life at pleafure to an indefinite length,, of .refcuing
man from the 'grave, and of making him immortal
upon earth. . f f
Such were the extraordinary views and puriuits ot
the alchemifts. The exaft period of the origin of this
ftudy is unknown*, nor can it now be afcer.tained
progrefs it had made, or indeed whether it was at all
cultivated among the antients. Julius Firmicus Ma-
ternus is the firft hiftorian who mentions this ftudy as
well known in his day, and the period when he flou-
riftred was about the beginning of the ’4th century.
A fubfequent author, ALneas Blafius, who.lived in the
following century, alfo makes mention of it: and bw-
das defines the term by informing us, that it is the art
of making gold and filver. Dioclefian, he fays, pro¬
hibited all chemical operations, during his perfecution
of the Chriftians, that his fubjefts might not be infti-
gated to afts of rebellion againft him by the formation
of gold. In fome places where gold is waftied down
in minute particles, by brooks and rivulets from the
mountains, it is cuftomary to fufpend the {kins ot ani¬
mals in the water, by which means the particles con¬
taining the gold are detained*, a circumftance from
which°the fabulous ftory of the golden fleece probably
derived its origin. Suidas, however, who. flounihed
in the 10th century, is not entitled to any high
of credit, efpecially as the antient authors are wholly
filent as to the fubjeft of alchemy. .
It is from the phyficians of Arabia that we ob¬
tain the moft fatisfaflory evidence concerning al¬
chemy. Avicenna, who lived in the 10th century,
is faid to have written on this fubjeft, according to
one of his own difciples, who likewife takes notice
of
C H E M I
Zi.troduc- of rofe-water and fome other chemical preparations j
tlor1, and in the I 2th century we find the cultivating an ac-
’ ' quaintancewith the cbemifts recommended tojhyficians.
Another Arabian writer fays, that the method of pre¬
paring rofe-water, &c. was at that time well under-
itood. Thefe proofs of the exiftence of alchemy a-
mong the Arabians, and particularly from the particle
Al prefixed to it, have induced fome to conclude, that
the doflrine of the tranfmutation of metals firft ori¬
ginated with the Arabians, which the crufades were
inftrumental in introducing into Europe, as well as
the rapid conquefts of the Arabians, in Europe, Afia,
and Africa. At that period Europe was in a flate of
the utmoft barbarity, owing to the incurfions of the
northern nations \ but fome of the fciences, among
which alchemy was comprehended, were happily re¬
vived by the Arabians : and about the middle of the
17th century, the extravagance of fuch as were the
profeffors of alchemy arrived at its greateft height.
It appears that the alchemifts began to be eftablilh-
ed in the weft of Europe, as early as the ninth cen¬
tury ; and between the eleventh and fifteenth cen-
Principal turies> ftudy was in its moft flourifliing ftate. A-
alchetnifts. mong the principal alchemifts who flourifhed during
this period, and who were diftinguilhed for their dif-
coveries and writings, were Albertus Magnus, Roger
Bacon, Arnoldus de Villanova, and Raymond Lully.
They all lived in the 13th century. Albertus Magnus
was a Dominican monk of Cologne, and was regarded
by his cotemporaries, no doubt on account of his ftu-
dies, as a magician. He was born in the year t 205,
and died in 1 280. He left numerous works, one of
the moft curious of wdiich is a treatife entitled De Al-
chemia, which exhibits a diftindl view of the ftate of
chemiftry at the time he lived. Roger Bacon, ano¬
ther monk, was born in the county of Somerfet in
England, in 1214, and died in 1294. He was cele¬
brated for many ingenious inventions and difcoveries
in chemiftry and mechanics. Among thefe are men¬
tioned the camera obfcura, the telefcope, and gunpow¬
der. His works difcoyer aftonilhing fagacity and acute-
nefs, and confidering the age in which he lived, are
compofed with no fmall degree of elegance and con-
cifenefs. Some of them, however, bearing the cha-
ra£ler of the times, are myftical and obfcure. Ar¬
noldus de Villanova, was a native of Languedoc in
France, and was born about the year 1240. He has
mentioned the mineral acids, and joined to his chemi¬
cal ftudies, extenfive knowledge in medicine. His
writings are diftinguifbed by all the obfcurity of the
alchemiftical authors. Raymond Lully, whofe reputa¬
tion raifed him to the rank of adept, was born at Bar¬
celona in 1235. He wrote on ftrong waters and me¬
tals. His laft will and teftament is one of the moft
celebrated of his writings, which are not lefs obfcure
than thofe of his cotemporaries.
About the end of the 14th century, Bafil Valentine,
a German Benedi&ine monk, was the firft who for¬
mally applied chemiftry to medicine. He was the
original dilcoverer of many of the virtues of antimonial
medicines j and in his celebrated treatife on antimony,
entitled currus triumphalis antimonn, are found many
preparations which have fince been announced to the
world as new difcoveries. About the fame time lived
Vol. V. Part. II.
S T R Y. • 425
Ifaacus Hollandus, whofe works have been greatly Introduc-
commended by Boerhaave. t’°n' .
In the beginning of the 16th century arofe Paracel- ^
fus, one of the molt extraordinary men who ever lived. Paracelfus
He was born in 1493, near Zurich in Switzerland.
Of a bold and enterprifing fpirit, he defpifed the com¬
mon rules of conduft by which men are ufually guid¬
ed. By this means he raifed his reputation to a great
height ; he became an enthufiaft in chemiftry, and in
the application of fubftances prepared by chemical pro- ^
ceffes to the cure of difeafes. He was the firft public the firlt
teacher of chemiftry in Europe, having been appointed public
to deliver leftures on that fubjeft in the city of Bafil:
but his reftlefs fpirit did not permit him to remain long
in this fituation. In two years he was involved in a
quarrel with the magiftrates, from whom he had re¬
ceived his appointment, and he left the city. Defpi-
fing the common principles of medical pratftice, and
having performed fome wonderful cures by the free
ufe of opium«and of mercury, he thought he had dif-
covered the univerfal medicine, and promifed immor¬
tality to himfelf and to his patients. But while he.
thus made fuch flattering promifes, his own fate was
a fad proof of the futility and abfurdity of his do&rine.
For after an almoft uninterrupted courfe of debauchery;
having wandered a great part of his life from place to
place, he died at an inn in Saltzburg, in the 48th year
of his age.
A great number of medical praflitioners, in the
courfe of the 16th century, adopted and propagated
the principles of Paracelfus. Among the moft diftin¬
guilhed of thefe was Van Helmont, a man of confidera-
ble genius, who was born in the year 1 Sll' Many of the
followers of Paracelfus were greatly devoted to the ftudy sg
of chemiftry; and this, with the abfurd and unpvinci-Alchemy
pled conduft of their mailer, tended not a little to bring declines,
the views and fpeculations of the alchemifts into difre-
pute. Chemiftry, now freed from the trammels of al¬
chemy, confided only oi a number of detached, un-
connefted fads. To bring thefe facts together in one
point of view, and to arrange them into clafles, lo that
the knowledge of them might be applied to ufeful pur-
pofes, and to thofe objefts to which future refearches
might be advantageoully dire&ed, were now wanted. ^
This talk wras accomplilhed by Beecher, who diftin- Chemiftry
guilhed himfelf by the extent of his views, in a work adumes the
entitled, Phyfica fubterranea, which was publilhed at a
Frankfort in the year 1669. This was the firft dawn
of chemical fcience, and the publication of Beecher’s
work formed an important aera in the hiftory of its
pr$grels. _ 30
In taking a retrofpe£live view of the progrefs of Difcoveries
chemiftry, previous to the publication of Beecher’s ^ the al-
work, we find that a great number of important faifts "hemi1
had been difeovered and colle&ed. To the clafs of
acids, the fulphuric, the nitric, and the muriatic were
added; the alkalies were better known, and the volatile
alkali was obtained from fid ammoniac by Bafil Valen¬
tine, by decompofing it by means of foda or potafs ;
the fulphate of potafs prepared in three or four different
ways, received as many different names; the nitrate of
potafs was called nitre, a name which was formerly ap¬
plied to foda ; Sylvius difeovered the muriate of potafs,
which he denominated digeftive fait ; and Glauber,
3 H the
426 C H E M 1
Introduc- tlie fulplidte of foda, to which he gave the name of
Uon- wonderful [alt, though better known by the name of
““r^v Glauber’s fait, by which it is {till diftinguifhed. Some
of the earthy falts began to be known about this period,
and among others the muriate of lime, which received
the name of fixed fal ammoniac.
The earths themfelves w’ere alfo better knowm } lime
water was prepared, and fome of the alkaline fulphu-
rets were pointed out and examined.
The properties of fome of the metallic falts were
fludied and examined ; the nitrate of filver, under
the name and form of cryjlals of Diana, and of lapis
inf emails ; the muriate of filver, under that of luna
cornea. The two muriates of mercury were defcribed,
and employed for various purpofes. The red precipi¬
tate, arcanum coralhnum, faccharum faturni or fugar of
lead, the butter of antimony, and the pow^der of alga-
roth, were either difcovered, or their properties more
attentively inveffigated and afcertained.
During this period alfo, the diftindfion was made
between the brittle and the dudlile metals. Bifmuth,
wine, antimony, and even arfenic itfelf, were obtained
in a metallic Ifate. A number of oxides, fome metal¬
lic dyes, fulminating gold, turpith mineral, the faline
precipitates of mercury, or the mercurial oxides of dif¬
ferent colours j minium and litharge, colcothar, the
faffton of Mars, and diaphoretic antimony, were dif¬
covered, and their preparation fufficiently defcribed.
During this period, the preparation of oils by diftil-
lation commenced, and the diftindlion was made be¬
tween volatile and empyreumatic. Ethers wTere difco¬
vered, and the fpirit of wine was well knowm by the
i fame name, alcohol, wThich it at prefent bears.
Then- hi- But however extravagant it may feem to us, the hif-
ftory ufeful. tory of the alchemifts is inftrudlive, as it affords a ufe-
ful leffbn to moderate our expectations in the purfuit of
knowledge, and to reftrain them within the bounds
which the Almighty has preferibed as the range of our
inveftigations ; lor of the knowledge and of the powyer
of man, as well as of that of the natural elements, he
has probably fixed the limits, and faid : Hitherto lhalt
thou come, but no farther. This hiftory is inftruftive
alfo, as it prefents a Angular and extraordinary feature
in the hiftory of mankind 5 but it is immediately ufe-
ful to our prefent purpofe, as it (hews us the commence¬
ment of chemical refearches. It is true, chemiftry in
the hands of the alchemifts, like every other depart¬
ment of knowledge during the dark ages, was involved
in myftery, and the knowledge of it communicated in
a barbarous jargon, to be underftood only by the ini¬
tiated, and fcarcely to be decyphered and comprehend¬
ed at the prefent day, with the afliftance of the exten-
five knowledge of chemical fads which we now poffefs.
But notwithftanding the extravagance of the objeCls
they purfued, the means they employed wTere ufeful to
the progrefs of chemiftry. By their inceffant labours,
difeovery wras added to difeovery, fa&s were multiplied
on fads, but without any regular train of refearch or
reafoning being followed.
But notwithftanding thefe important difeoveries, it may
^ appear furprifing that they were not more numerous.
Their dif- The alchemifts had laboured inceflantly in chemical pur-
roveries fuits for near a thoufand years, and with all the zeal and
compara- arclour 0f enthufiafts; the labour of whole lives was ex-
u ei;. tew. ktnifted, and immenfe fortunes were diftipated in en-
S T . R Y.
deavouring to obtain the grand objed of all their re- Intioduc-
fearches. Confidering the long period during which .  ,
they flourifhed, and the numbers who were employed
in thefe purfuits, there is indeed room for w'onder, that
they bequeathed to the firft fcientific inquirers fo imall
a flock of chemical knowledge. But the fpirit which,
prevailed among the alcheraifts was direftly hoftne to
the free communication and accumulation of know- ^3
ledge. The prominent feature of the charafter of the The reafon-
alchemifts was fecrecy. This indeed was clofely con¬
nected with the nature of the objeft, to attain which,
all their purfuits and inquiries were direCted ; and fo
ftrongly was this imprefted upon their minds, that they
believed, or pretended to believe, that the dreadful
wrath of heaven wrould fall on him who ftiould prefume
to difclofe to any, but to the initiated, the feciets of tne
art. That fpirit, which arofe from motives of avarice
and felf-conceit, became at laft one of the leading prin¬
ciples of their conduCf. With fo great, fo important
an objeCt in view, as the difeovery of the means of put¬
ting themfelves in pofieflion of unlimited wealth, it is
little to be wondered at, if they ftrould carefully con¬
ceal from the world, and even from each other, the
fteps in the progrefs which led to the accomplilhment
of this end. Thus, all their proceffes were carried on
in private, and all their difeoveries wTere kept fecret.
In their pretended communication of knowledge with
each other, they employed certain figns and figures,
and affumed a myfterious mode of writing, that they
might be underftood only by adepts, and might be to¬
tally unintelligible to the reft of mankind.
Confidering this fpirit, and the charaCler which dif-
tinguifhed the alchemifts, it was fcarcely to be expeft-
ed that they Ihould reveal to the world, either by
fpeech or writing, difeoveries w7hich moft of them pro¬
bably believed were to be of fuch vaft benefit to them¬
felves. And in this view, we ftiould rather be furprifed
that any of their proceffes were ever made known.
But here vanity, and even avarice, probably had con-
fiderable influence in calling forth what they pretend¬
ed was an account of their attainments and diicoveries.
Some of the alchemifts, perhaps by means of trick and
impofture, had acquired a high reputation for knowr-
ledge, and had impofed a belief on many, that they
were adually in pefleflion of the philofopher’s ftone.
They were therefore fought after, and often received
great rewards for their labour, in proving the efteCIs,
or trying the fuccefs of this wonderful agent. To be
thus employed was perhaps the objeCI of many in ^the
publication" of their works. But at the fame time, they
cautioufly avoided revealing their knowledge, by em¬
ploying myfterious and metaphorical language.. Thus
we may account for the impenetrable obfeurity and
numerous abfurdities which characterized their writ-
ings.
In this view, therefore, of the charaffer of the al¬
chemifts, it is not to be expefted that the ftore of
chemical fafts could be very ample from their la¬
bours. And indeed, confidering the caution with
which they concealed and carried on all their procehes,
it is not improbable that many important ditcoveries
were never announced by the firft obfervers •, for the
very appearance of any thing new or unexpected, would
flatter their hopes that they had advanced another ftep
towards the attainment of their objeft, and that the next
would
Introduc¬
tion.
34
Stahl im¬
proves the
theory of
Beecher.
35
Chemiftry
iludied in
3&
Britain.
37
In France.
3^
Black’s dif-
-covery.
C H E M I
would put tliem in full pofleflion of it. Thus, fuch a
difeovery would be held inviolably fecret, and in this
way it might be loft for ever.
We have already mentioned, that the work of Bee¬
cher gave the firft fcientific form to chemical know¬
ledge. This appeared about the middle of the feven-
teenth century, w'hen the light of knowledge began
to fpread over Europe, and chemiftry received its
fhare. The fa61s which had been accumulated by the
labours of the alchemifts, and to which Beecher had
given a fyftematic form, were ftill farther methodized
and extended by his pupil Stahl. Indeed fo much
was done by the latter, in fimplifying and improving
the theory of his mafter, that it was afterwards deno¬
minated from his name the Stahlian or phlogijlic theory.
This theory was then received and adopted by all
chemifts, and continued to flourilh for more than half
a century.
After the middle of the fever.teenth century, the efta-
bliftiment of philofophical focieties in Europe greatly
contributed to the diffufion of knowledge. It w’as about
this time that the academy of fciences was eftablilhed
in France, and fome of its members rofe high in re¬
putation by their experiments and dilcoveries in che¬
miftry. The royal fociety of London was alfo found¬
ed about the fame period •, but its members, after the
example of Newton, were more occupied in mechani¬
cal philofophy, and paid lefs attention to chemical fei-
ence. It was not, however, entirely overlooked.
Newton himfelf threw out fome important hints, and
took fome general views of chemical phenomena j
Boyle, along with his refearches in mechanical philo¬
fophy, profecuted the ftudy of chemiftry ; and the ex¬
periments of Hooke and Mayow, on the nature of com-
buftion and refpirable air, difeover no mean degree
of fagacity and Ikill in their inveftigations.
Towards the middle of the eighteenth century, the
ftudy of chemiftry became general, and even falhion-
able, in France. Before this time Homberg, Geoffrey,
and Lemery, had diftinguiftied themfelves by their
chemical experiments and difeoveries. Among thefe
Geoffroy is ftill defervedly celebrated for his inven¬
tion of the tables of chemical affinities, an ingenious
method of exhibiting, at one view, the principal re-
fults of experiments in this fcience. Thefe tables were
afterwards improved by feveral chemifts, but efpecially
by Rouelle, Wenzel, and Bergman.
But the difeovery of Dr Black formed one of the moft
important mras in the hiftory of this fcience, and gave
a new and unexpefted turn to the views of chemifts.
It was the objeft of Dr Black’s refearches to difeover
the caufe of the remarkable change which a piece of
limeftone undergoes when it is calcined or burnt, and
to point out the reafon of the great difference of the
properties of this fubftance in its different ftates \ and
his inveftigations were crowned with fuccefs. For,
in the year 1755, he afeertained that thefe changes
were owing to the combination or feparation of a pe¬
culiar kind of air, different in its properties from. the
air of the atmofphere. When this air is combined
with lime, it is in the mild ftate, or the ftate of
limeftone *, rvhen this air is driven off, which is the
procefs of calcination or burning, the limeftone has
changed its properties ; it is reduced to the cauftic
ftate, and has loft confiderably of its weight; and this
$ T R Y. 427
lofs of weight, Dr Black proved, was exactly equal to Introduc-
the weight of the air wffiich had been driven off. To t'^‘n' ,
this air Dr Black gave the name of Jixed air ; becaufe,
when united to the lime and other fubftances, with
wffiich it enters into combination, it is in a fixed ftate.
This difeovery, one of the moft important in chemiftry,
opened a new field for inveftigation j for it had not
been once fufpe£led, that aerial fubftances formed com¬
binations wdth folid bodies.
From this time, the progrefs of chemiftry w7as ra¬
pid and brilliant. Fa6Is and difeoveries were daily mul¬
tiplied, and a fpirit of enthufiafm for the ftudy burft ^
forth, and wras diffufed far and wide. In the year Other im-
1774, Dr Prieftley, who had contributed largely toPortan,: ^
the flock of chemical knowledge, difeovered pure orcovenes''
vital air, and that this air only was fit for the purpofes
of refpiration and combuftion. In the year 1781 Mr
Cavendifh, another ingenious Engliffi chemift, proved
that water is not a fimple element, but that it is com-
pofed of pure or vital air, and inflammable air ; or,
in chemical language, of oxygen and hydrogen.
But, previous to this time, two chemifts had ap¬
peared in Sweden, had diftinguifhed themfelves by
their zeal, ingenuity and indefatigable induftry, and
had merited and obtained the higheft reputation for
the valuable difeoveries which they had made in che¬
mical fcience. Thofe who are at all acquainted with
the hiftory of chemiftry, need not be told, that thefe
celebrated names are thofe of Bergman and Scheele j
names which will not be forgotten as long as modefty,
candour, and truth, are honoured and refpedled among
mankind.
In the mean time, the French chemifts w7ere not idle.
The celebrated Lavoifier, in conjun&ion with fome of
his philofophical friends, confirmed, by the moft deci-
five experiments, the truth of Mr Cavendifli’s difeovery
of the compofition of wmter, which was now received
and adopted by almoft every chemift. The fame un¬
fortunate philofopher, whofe bright career was cut
ftiort by the horrors of the French revolution, had, pre¬
vious to the time alluded to, enriched chemical fcience
with many valuable and important fads. He had
greatly contributed to overthrow7 the phlogiftic theory,
by a feries of accurate experiments and obfervations on
the calcination of metals. It had now become a que-
ftion, whether metals, during the procefs of calcina¬
tion, gave out any fubftance ; that is, whether they
contained any phlogifton ; and Lavoifier inconteftably
proved, that metals cannot be calcined, excepting in
contad with pure air, and that the calx thus obtain¬
ed was, in all cafes, exadly equal to the weight of
the metal, and the quantity of air which had difap-
peared.
Chemiftry, by its rapid and unexampled progrefs,
had now fo far extended itfelf, and had accumulated fo
large a body of fads, that the barbarous, unmeaning,
and arbitrary language which the alchemifts employed
to veil their mvfteries, and part of which had been
adopted and imitated in language equally obfeure and
arbitrary by the earlier chemifts, rendered it extremely
difficult to be acquired or underftood. This was^ loud¬
ly and juftly complained of, but the difficulties in the
way of remedying it feemed almoft infurmountable. 4^
The French chemifts, however, undertook the arduous™^-
talk, and completely fucceeded in their labours. Toture>'
3 H 2 thefe
428 C H E M I
Introduc- tliefe illuftrious pliilofopliers we are indebted for the
tion. prefent language of cheraiftry, which is fo conftrudted,
tjiat every word, and every combination, has an appro¬
priate meaning, and is intended to exprefs the nature
and compolition of the fubftance which is reprefented.
It is to this improvement in its language, that we are
to afcribe the facility and precifion with which the
knowledge of chemiftry can now be communicated,
and which has undoubtedly contributed greatly to its ge¬
neral diffufion and cultivation. And if there be any
ground for hope of its future progrefs, from diftinguhh-
ed talents, ardent zeal, and unceafing induftry, thoi'e
who are now engaged in the ftudy of this fcience, give
fair promife of a rich harveft.
Sect. IV. Of the Tiijl Principles of Bodies, and of the
Methods of Jiudying and arranging them.
Elements of j. According to the ancient philofophers, all matter
bodies a- confided of four principles or elements. Thefe were
mong the fire^ a;r^ water} anci earth ; and this opinion, with cer-
ancients. modigcat;ons> feems to have univerfally prevailed.
But the difeoveries of modern chemiftry have proved,
that three of thefe elements, at leaft, are compound
fubftances. Fire is a compound of light and heat ; air
is compofed of oxygen and azotic gafes j and water con-
fifts of oxygen and hydrogen.
The alchemifts, not fatisfied with this divifion of the
principles of bodies, adopted another, which was more
appropriate to the nature of their labours and experi¬
ments, and was better calculated to explain the appear-
The alche- ances with which they were acquainted. The elements
milts. of all bodies, according to their theory, w’ere>//,>//>/jar,
and mercury : and thefe were long known among the al-
chemifts by the appellation of the trio prima. Thefe prin¬
ciples were admitted by all the alchemiftical writers till
the time of Paracelfus,who alfo adopted them, and added
two more to the number. Thefe five elements or prin¬
ciples are thus chara&erized. Every thing came un¬
der the name of fait which was foluble and fapid ; all
inflammable fubftances were called/z///>£z/r ; and every
volatile fubftance, which flies off without burning, w*as
called mercury or fpirit. What w^as liquid and inftpid
was called phlegm or water; every thing that was dry,
infipid, fixed, and infoluble, w^as called earth, or caput
mortuum. The two laft, which were added by Para-
celfus, are the water and earth of the ancients. Ac¬
cording to the original theory of the alchemifts, all bo¬
dies may be decompofed by fire, and refolved into
their three conftituent principles. The mercury or fpirit,
during the procefs of combuftion, efcapes in the form
of fmoke ; the fulphur is inflamed •, and the fait, which
43 was fuppofed to be the fixed principle, remains behind.
Beecher’s But Beecher, whom we have already mentioned as
elements. t’ne founder of chemical fcience, perceiving the vague
and unfettled notions of the alchemifts, with regard to
the principles of bodies, generalized and fimplified
ftill more, the chemical fa£ls which were then known.
According to his theory, all bodies confifted of earth
and water. Under the former he included every thing
that was dry, and under the latter, whatever was hu¬
mid. He admitted three earthy principles, namely,
the fufible earth, the inflammable earth, and the mer¬
curial earth. The firft was the principle of drynefs,
of infufibility and hardnefs. The fufible earth, com-
s T R Y.
bined with water, compofed an acid, which was call- Introduc¬
ed the univerfal acid, becaufe all other acids owed , non‘
their properties to it. The inflammable earth was
confidered as the principle of combuftibility •, and the
mercurial earth was the principle of volatility. T he
fufible and the mercurial earths, with water, compofe
common fait j and the inflammable earth, with the
univerfal acid, forms fulphur. The metals were com¬
pofed of thefe three earths in equal proportions. When
the mercurial earth was in fmall proportion, the com¬
pound was fone ; when the fufible wras in greater pro¬
portion, the compound was precious fones; and the
compounds are the colorific earths, when the inflam¬
mable earth is in the greateft, and the lufible in the
fmalleft proportion. ^
This theory of Beecher was confiderably modified Stahi*s.
by his pupil Stahl. The inflammable earth of Bee¬
cher feems to have been changed by him into the prin¬
ciple of inflammability or fixed fire, which he diftin-
guifhed by the name of phlvgifon. He admitted the
univerfal acid, but rejefted the mercurial earth. The
number of elements in the theory thus modified by
Stahl, amounted to five. Thefe were, air, watert
pblogifon, earth, and the univerfal acid.
This mode of confidering the elements of bodies, or
their firft principles, and of admitting fuch arbitrary
and erroneous diftin&ions, is juftly banifhed from che¬
mical fcience. All fubftances are fuppofed to be fim-
ple, wdiich have not been decompofed, without regard
to their primitive elements or principles, the knowledge
of which is, perhaps, beyond the reach of human power
ever to arrive at.
2. To acquire the knowledge of thofe properties of
bodies, inveftigation of which is properly included un¬
der the chemical fcience, two methods are employed :
The one is the method of analyfis or decompofition, the
other is that of fynthefis, or compofition. By the one,
the different Ample fubftances of which compound bodies
confift, are feparated, and their properties individually
examined by the other, the Ample fubftances are com¬
bined together, and the properties of the new com¬
pound are confidered and inveftigated.
Different kinds or modes of analyfis have been admit-^nalyils.
ted and deferibed by chemical writers. Some bodies,
when expofed to the a£lion of heat and air, undergo a to¬
tal reparation of their component parts. This is called
fpontaneous analyfis. Thus, fome minerals, and all ve¬
getable and animal matters, when they are deprived of
life, in favourable circumftances flowly feparate into
their component parts \ and in the fame way the prin¬
ciples of which fome liquids are compofed, re-adl on
each other, and fpontaneoufly feparate, which gives an
opportunity of inveftigating the nature of thefe fub¬
ftances.
Analyfis by fire, operates by the accumulation of
caloric in bodies ; and by the power wdiich it has of
feparating their particles to favour their examination.
But this inftrument of analyfis is to be confidered only
as one of the means which fhould concur with many
others, to throw light on the real compofition of bodies.
For it will afterwards appear, that the different quan¬
tities of caloric accumulated in bodies, have the great-
eft effefts in giving different refults, and changing the
order of decompofition.
Another mode of analyfis is by means of re-agents.
This
45
Synthefu.
C H E M I
This is conducted by placing the compound body which
is to be examined, in contad with various fubliances,
which have the power offeparating its conllituent parts.
It is here that the genius and fcience of the chemift
appear molt confpicuous j for every fubftance in na¬
ture, and all the products of art, become valuable in-
ftruments in his hands, to afcertain the nature, and to
examine the properties, of the fubftances which come
under his examination. The different means of ana-
lyfis which chemilts have employed, to arrive at the
knowledge of compound bodies, have been deemed of
fuch importance and utility, that chemittry has been
called the- fcience of analyfs.
Synthefis, or compofition, is the union of two or
more limple fubftances. This union, from whence
refults a new compound, has become an important
ftep in arriving at the knowledge of the properties
of bodies, and in forming a number of produfts ufe-
ful in the arts, and neceffary to our wants \ and thus it
is confidered by chemifts as in fome meafure the in-
verfe of the method of analyfis, as the perfe&ion of
their art, and one of the great inftruments of their
operations. The method of fynthefis or compofition,
confidered as a chemical proceis to acquire the know¬
ledge of the intimate and reciprocal adlion of bodies,
is in reality more frequently employed than that of
analyfis j and the name of the fcience, if we were to
regard thefe two methods, fliould rather be called the
fcience of fynthejis than the fcience of analyfis. In all
cafes of complicated analyfis, the operations are fyn-
thetic. Compounds of an inferior order are formed,
but more numerous than the firft compounds which
were fubje&ed to analyfis or examination.
But befides, there are many bodies which have ne¬
ver yet been decompofed. It is only by compofition
or fynthefis, that is, by combining them with others,
and by examining the nature of the compounds which
are formed by this combination, that their chemical
properties can be inveftigated.
However various the operations of chemiftry may
be •, however numerous and different from each other,,
the refults which are obtained •, they may all be refer¬
red to analyfis or fynthefis, and be regarded either asr
combinations or decompofitions 5 and to thefe two ge¬
neral methods, all our operations may be limited.
3. It muft be univerfally allorved, that it is of vaft
importance, in acquiring or communicating knowledge,
to have a clear view of the obje£ls of our ftudies j and
this becomes the more neceffary, as the fafts in any
fcience are accumulated, and the objedls wdrich it
comprehends become more numerous. In many of
the arrangements of chemical knowledge which have
been propofed to the world, the objetffs of this fci¬
ence have been claffed together according to certain
refemblances in one or two points, while they are to¬
tally diftinft in all others.. But an arrangement which
is founded on the properties and characters of fubftances
which have not been fully afeertained and generally
admitted, muft tend to obftrutt, rather than facilitate
the acquifition of fcience. If, for inftance, the objects
of chemical knowledge are to be arranged according
to their combuftibility or incombuftibility, the nature
of the procefs of combuftion ftiould be fully under-
ftood, and the effeft of combuftion on the fubftances
to.be claffed in this way, clearly eftablilhed. If all
turn.
47
S T R Y. 42!>
this has not been previoufly attended to, the principles Introduo-
of the arrangement muft be falfe, and muft unavoid- v
ably lead to error. As a proof of the truth of our re¬
marks, the fame fubftance has been confidered by one
chemift as a combuftible body, while it is arranged by
another among the clafs of incombuftibles ; and even by
the fame chemift it is faid to be combuftible at one
time, and incombuftible at another, according to the
theory which then prevails.
Without purfuing any method of arrangement
founded on particular theories or lyftems, we (hall en¬
deavour, in the following treatife, to lay before our
readers a full view of the prefent ftate of chemical
fcience ; and in arranging the great body of fa61s of Arrange-
which the fcience confifts, we flrall oblerve the twoment*
following rules. 1. To introduce the fubttances to be
examined according to the fimplicity of their compo¬
fition 5 and, 2. According to their importance as che¬
mical agents. The plan which wTe propofe to purfue,
in treating of thefe different claffes of bodies, is, 1. To
confider their properties as fimple lubftances, and, 2.The
combinations which they form with thofe which have
been already deferibed. By this method of arrange¬
ment, and by following out this plan, we hope to
have lefs anticipation and repetition than in moft other
fyftems which have yet been propofed. But we wifli
not to think too confidently of our own labours. We
(hall probably be confidered by the world as the worft
judges in this cafe ; and we are not too felfiftr to fub-
mit to the opinion of thofe to whom it is addreffed,
to whofe candour and impartiality wTe implicitly truft.
We may however, obferve, that this arrangement has
been found extremely convenient for teaching the
fcience ; and we hope that our readers will find it
equally fo in acquiring the knowledge of it.
According to the principles which we have ftated,
the following table exhibits a view of the order which
we (hall obferve in this treatife. In the prefent ftate
of chemical fcience, and in its application to explain
the phenomena of nature, or to improve the arts of
life, the whole may be conveniently arranged into?
twenty chapters.
I. Affinity.
II. Light.
III. Heat.
IV. Oxygen Gas.
V. Azotic Gas, and its combinations^
VI. Hydrogen, &c.
VII. Carbone, &c.
VIII. Phosphorus, &c.
IX. Sulphur, &c.
X. Acids, Sec.
1. Sulphuric,,
2. Nitric,
3. Muriatic,
4. Oxymuriatic, &c. &e.
XI. Inflammable Substances.
1. Alcohol,
2. Ether,
3. Oils.
XU. Alkalies.
1. Potaftr and its combinations,
2. Soda, &c.
3. Ammonia, &c.
* XIIL
CHE
XIII. Earths.
1. Lime and its combinations,
2. Barytes, &c.
3. Strontites, &c.
4. Magnefia, &c.
5. Alumina, &c.
6. Silica, &c.
7. Yttria, &c.
8. Glucina, &c.
9. Zirconia, &c.
XIV. Metals.
1. Arfenic and its combinations.
2. Tungften, &c.
3. Molybdena, &c.
4. Chromium, &c.
5. Columbium, &c.
6. Titanium, &c.
7. Uranium, &c.
8. Cobalt, &c.
9. Nickel, &c.
10. Manganefe, &c.
XI. Bifmutb, &c.
12. Antimony, &c.
13. Tellurium, &c.
14. Mercury, &.c*
15. Zinc, &c.
16. Tin, &c.
17. Lead, &c.
18. Iron, &c.
19. Copper, &c.
20. Silver, &c.
21. Gold, &c.
22. Platina, &c.
XV. The atmosphere.
XVI. Waters.
1. Sea water,
2. Mineral waters.
XVII. Minerals.
1. Component parts,
2. Analyfis.
XVIII. Vegetables.
1. Functions,
2. Decompofition,
3. Component parts.
XIX. Animals.
1. Fundtions,
2. Decompolition,
3. Component parts.
XX. Arts and Manufactures.
1. Soaps,
2. Glafs,
3. Porcelain,
4. Tanning,
5. Dyeing,
6. Bleaching.
explained. In the above arrangement, the firft chapter treats of
affinity, or the laws of chemical adlion. In the two
following chapters, the properties of light and heat are
detailed. Thefe are confidered as material fubftances 5
but their properties can only be known in combina¬
tion with other bodies, as they have never been found
in a feparate date. Oxygen, azote, and hydrogen,
which are confidered as the balls of oxygen, azotic,
and hydrogen gafes, are treated of in the 4th, 5th,
M I s T R Y.
and 6th chapters; but thefe fubllances, as well as Introdw.
light and heat, are not cognizable by our fenfes., tlon^
They are only known in a ftate of combination, the
aeriform or gafeous Hate, when they are combined with
caloric, or the matter of heat. The three following
fubftances, carbone, phofphorus, and fulphur, which
are the fubje&s of the 7th, 8th, and 9th chapters, are
confidered as fimple, becaufe they have never been de-
compofed. They can be exhibited in the folid ftate.
Two of them being very abundantly diffufed in nature,
and entering into an immenfe number of combinations
with other bodies ; and the third, namely, phofpho¬
rus, poffefling very fingular properties, it becomes of
great importance that they fhould be early knowm.
The acids are treated of in the 10th chapter. They
are naturally arranged in this place, becauie the con-
ftituent parts of lome of the moft important are deriv- .si
ed from the fubftances which have been already treated
of. But the properties of the clafs of acid bodies
ought alfo to be early known, becaufe they are the
moft powerful inftruments of analylis in the hands of
the chemift. Indeed fuch is their importance in his
inveftigations, that in many of them he can fcarcely
proceed a fingle ftep without their aid.
The bodies treated of in the nth chapter, name¬
ly, alcohol, ether, and oils, under the head of in¬
flammable fubftances, are properly introduced, be¬
caufe the nature and properties of the fubftances which
enter into their compofition have been previoufly exa¬
mined j becaufe one of them is the refult of a chemical
aftion between the acids and alcohol j and becaufe feme
of them are employed as chemical agents. In the
12th, 13th, and 14th chapters, the properties and
combinations of the alkalies, earths, and metals, are
detailed. Excepting one, thefe three claffes of bodies
are fimple, undecompounded fubftances. Many of
them have long been the fubjefts of chemical invefti-
gation, and they afford fome of the moft important and
interefting chemical refearches. They are firft to be
treated of as fimple fubftances ; and next, as they enter
into combination with the different claffes of bodies
which are already knowm, particularly with that of
the acids, forming the numerous claffes of alkaline,
earthy, and metallic falts, moft of which are of vaft
importance, not only as objedls of chemical refearcb,
but alfo of extenfive utility in the arts of life.
In the fix following chapters, our chemical know¬
ledge is to be applied in explaining the appearances of
nature, fo far as thefe are fuppofed to depend on che¬
mical aflion. The 15th chapter treats of the chemi¬
cal changes and combinations which take place in the
atmofphere. The waters, as they are found on the
earth *, the different ingredients with which they are
impregnated ; the nature and quantity of thefe ingre¬
dients, and the methods of difeovering and afeertain-
ing them, form the fubjeft of the 16th chapter. The
17th chapter is employed in giving a view of the com¬
ponent parts of mineral produ&ions, and in deferibing
the methods of analyzing or feparating the parts which
enter into their compofition. The funftions of vege¬
tables and animals, or thofe changes which take place ^
in them m the living ftate, which feem to be depend¬
ent on chemical aftionj the changes wffiich they un-
ergo y pontaneous analyfis, or reparation into their
conftituent parts, and the nature and properties of
< thefe
43O
Introduc¬
tion.
j nity.
ill '
ion
led
C H E M
tliefe elements, will be the fubjedt of difcuffion in the
; 18th and 19th chapters. The 20th chapter, in which
chemical fcience is applied to the improvement of arts
and manufactures, is not one of the lealt important and
interefting, and a full view of this part of the fubjeCt
would exhauft the whole of the ufeful detail of chemi¬
cal knowledge. But, in the following treatife, it is
not propofed to enter at full length into the different
branches of the arts and manufactures, but only to give
a flight view of their general principles, fo far as they
depend on chemiflry, referring for the particular dil-
cuffion of each to the different heads under which they
will be found arranged in the courfe of the work.
Chap. I. Of AFFINITY.
Before we enter into the detail of thofe changes
which take place by the aCtion of bodies upon each
other, producing compounds which are poffeffed of to¬
tally different properties, and thus exhibiting the 'cha¬
racters of chemical addon, it is neceffary to take a
view of the eircumftances in which thefe changes are
effefted, or in other words, the laws of combination
or chemical affinity.
The term affinity, which is the expreffion of a force
by which fubitances of different natures combine with
each other, feems to have been pretty early employed
by chemical writers. Barchufen, it would appear, is among
thefirft who employedit,andthuscharaCterizes it. “Arc-
tam enim atque reciprocam inter fe habent affinitatem.”
It was afterwards brought into more general ufe, and its
application more precifely defined by Boerhaave*. His
words are remarkable. “ Particulae folventes et folu-
tae, fe affinitate fuse naturte colligunt in corpora homo-
genea.” And to explain his meaning ftill more clear¬
ly, he adds, “ non igitur hie etiam aCtiones mechani-
cae, non propulfiones violentae, non inimicitife cogi-
tandee, fed amicitia.” To avoid the metaphorical ex¬
preffion affinity, Bergman propofed the term attraShon ;
and to diflinguifh chemical attraction, which exifts on¬
ly between particular fubftances, from that attraction
which exifts between all the bodies in nature, he pre¬
fixed the word e/eSlive. The word affinity, however, is
now generally adopted, and employed by all chemifts.
The different tendency of bodies to combine with
each other, or the relative degree of affinity which ex¬
ifts between them, could not long be overlooked by
thofe whole attention was occupied in obferving che¬
mical changes. And to explain this dmerence of ac¬
tion, a maxim of the fchoolmen was adopted 5 Jimile
venit adfimile. The fame doftrine was held by Bee¬
cher, that fubffances which were capable of chemical
combination, poffeffed a fimilarity of particles. . Other
attempts were made to explain cnemical aCtion, by
confidering folvents as confiding of points, finer or
coarfer, which were mechanically difpofeti to enter in¬
to the pores of certain fubftances w’hich they were ca¬
pable of holding in folution. But Stahl, as appeals
from his works, rejeaed the notion of mechanical
force, and afenbes the power of folvents to contaa, or
to the attraaion of cohefion. “ Combinationes quaf-
cunque non aliter fieri, quam per araam appoiitionem.
And afterwards, he fpeaks ftill more precifely when he
fays, “ non per modum cunei, neque per modum 111-
curfus, in unam particulam feparandam, fed potius per
I S T R Y,
modum apprehenfionis, feu araae applicationis •,’* and
then he adds, “ eft inde rationi quam maxime confen-
taneum, quod effeaus tales potius araiore unione fol-
ventis cum folvente contingant, quam nuda et fimplici
formali inftrumentali divifione •j-.” f Sftcitv.
Having made this important ftep in the confidera- ^e^3er'
tion of chemical aaion, the experiments and obferva-1 ’
tions of the fagacious chemift led him to conclude,
that a combination between two fubftances once form¬
ed, could not be deftroyed, without effeaing a more
intimate union of one of the conftituent parts with fome
other fubftauce. 52 _
The next ftep in the method of obferving and Tables m-
ftudying chemical affinity was made by Geoffroy the'011 e J
elder. He colledled the fcattered faifts, to deter¬
mine the force or meafure of their degrees of union,
and to eftablifli rules of analyfis and compofition. His
firft table of affinity was prefented to the Royal Aca¬
demy of fciences at Paris in the year 1718. This con-
fifted only of 17 columns, which w-ere but imperfedlly
filled up, and exhibited rules which have been moftly
changed ; but with all its errors, it ought to be confi-
dered as one of the firft guides to chemical knowledge. ^
The firft material improvement on Geoffroy’s table enlarged^
was made by Geilert, profeffor at Freyburg. In his
Chcmia Metailurqica, publiftied in 1750, there is a
new table of affinity, which extends to 28 columns.
At the bottom of each column there is a lift of fub¬
ftances with which the body at the head of the column
had no a<ftion. Rudiger, in the year I75^» inferted a
table of affinity in his fyftem ofehemiftry, in which he 54
reduced the number of columns to 15* 1° this table and impro^
he placed the fixed alkalies and lime parallel wTith each
other, and before ammonia, the column of acids.
pointed out alio wdth a good deal of accuracy, in a
fmall feparate table, thofe fubftances which refine to
combine wdthout fome intermediate fubftance.
The next important addition to the knowledge oHy bun-
affinities, was made by IN'!. Limbourg. In his table k
the number of columns was extended to 33. 1 his ta¬
ble was the fulleft and moft accurate of any that had
yet appeared. He had juftly obferved that zinc, of all
metallic fubftances, ftiould be placed at the head in
the column of acids, and that even in the dry way it
precipitated them all. He afferted that lime and the
cauftic alkalies aefted by affinity on animal matters ;
and befides, he ftated fome cafes in which a change
took place in the order of affinities, by a change of
temperature, or by the volatility of one of tee lub-
ftances. p 56*
This fubjeft, the importance of which was fufficient- By Berg,.
ly obvious, was now affiduoufly inveftigated by many man.
chemifts. The number of tables was multiplied, and
the fyftem of affinity more fully eftabliihed. But the
greateft improvement which it had hitherto received,
was made by the celebrated Bergman, in his diflerta-
tion on eleflive attraiflions, publifhed in the tranfac-
tions of the Royal Society of Upfal, in the year 1775.
Thefe tables, editions of which appeared in 1779 and
1783, have been juftly regarded as ftriking inftances
of the fagacity and induftry of the author. The affi¬
nities of 59 fubftances are afeertained with great accu¬
racy \ and the diftinefion between thofe that take
place in the moift and dry way, is particularly ftated,
as well as the diftin&ion between fimple and compound
affinities*.
ved
55'
57 .
All bodies
attradl.
43 2
Affinity, affinities, wiiicli has led to the explanation of a great
v " '■ number of apparent anomalies. Since the time of
Bergman, this fubje£l has been profecuted by many of
the moil diftinguiihed philofophical chemifts. Among
thefe we may mention the induilrious and indefatigable
Kirwan of oar own country ; and among the French
• philofophers, Morveau, and more efpecially Berthol-
iet, diftinguiihed for his Ikill and fagacity, who has
lately in his refearches concerning the laws of affinity,
opened a new field of inquiry, corre£led many former
errors, and pointed out fome new laws in this intereft-
xng and important fubjedl.
All bodies with which we are acquainted, are influ¬
enced by a certain force, by rvhich they are attradled,
or drawn tovrards each other. A ftone, when it is
unfupported, falls to the ground j the planets are at-
tra&ed by the fun two polifhed plates of metal, of
glafs, or of marble, when brought into clofe contadl,
adhere with a certain force y a piece of wood or ftone
requires a confiderable degree of force to feparate the
particles, or to draw it afunder j and lime and fulphu-
ric acid enter into fuch clofe combination, that it re¬
quires an equal degree of force to overcome that com¬
bination, or to feparate the particles from each other.
Whatever may be the nature of thefe attraftions, or
the caufe of thefe different combinations, or whether
they are to be afcribed to the fame univerfal law per¬
vading matter, as fome have fuppofed, they have been
defcribed by philofophers under different names. The
attraction which exifts between all bodies in the folar
lyftem, was denominated by Newton, by the general
term attra&ion ; and he demonftrated that this uniform
and univerfal law was precifely the fame as the law of
gravitation, or the defcent of heavy bodies towards*he
earth ; and that this attraClion was an effential pro¬
perty of all matter 5 that the minuteft particles, in pro¬
portion to their bulk, were equally influenced with the
largeft maffes; that the fame power which retained the
planets in their orbits, gave form to the drops of rain.
We have faid, that thefe different forces or attrac¬
tions have been diftinguiihed by different names. That
attraftion which is exerted between two polilhed fur-
faces brought into contaCl, has been called adhejlon.
When particles of the fame nature are attracted or held
together, the expreffion of the force by which this is
effeCted, has received the name of cohejion, homogene¬
ous affinity, or the attraction of aggregation ; but when
diflimilar particles, or the particles of two fubltances
of different qualities combine together, the force or at¬
traction which is here exerted has been called hetero¬
geneous affinity, the attraction of compoftion ; or, ftriCt-
ly fpeaking, chemical affinity. In the three following
lections, we propofe to give an account of the opinions
and doCtrines wffiich have been held by philofophers
with regard to the nature and force of thefe attrac¬
tions. Of the two firft we ffiall only take a ftiort view;
but (hall enter more fully into the detail of the latter,
namely, chemical affinity, which more ftriCtly belongs
to our prefent fubjeCt.
Sect. I. Of Adhesion.
By adhefion, then, is to be underftood, that force
which retains different fubftances in contaCt wdth each
other. Thus, w7ater adheres to the finger, which is
CHEMISTRY.
SS
Different
names of
affinity.
faid to be wet, and mercury brought into contaCi W'ith Affinity,
gold, adheres with great force. Adhefion takes place,v—
either between two folids, as marble or glafs ; cr be-jnwq^t
txveen folids and fluids, as when water rifes in capilla-circurnftan_
ry tubes; or between two fluids, as water and oil. Incesithap-
an experiment made by Dr Defaguliers, he obferved,Pens*
that two plates of glafs, of one-tenth of an inch in dia ¬
meter, adhered with a force equal to 19 ounces. The
adhefion of two fluids has been proved by the experi¬
ment of Lagrange and Cigna, as that of oil and ■water,
between which it wras formerly fuppoied there exifted
a natural repuliion ; and the experiments on capillary
attraction, and particularly the afcent of water between
two panes of glafs, which was afcertained by Dr Brook
Taylor, have eftabliffied the attraction between folids
and fluids.
This adhefive force, or the caufe of this attraction, Accounted
has been differently accounted for by philofophers. Intor*
a differtation on the weight of the atmofphere, pub-
liflred in 1682 by James Bernouilli, he afcribes the
refiftance which two poliffied pieces of marble oppof-
ed to their feparation to the preffure of the air; and
in proof of this, he ftates as a faCt, that the two plates
could be eafily feparated in vacuo. But it has been
fuppofed that he had either never attempted to verify
this faCt, or that the experiment had been accompanied
by fome fallacy. From the experiments made by Dr
Taylor, he concluded that the intenfity of the adhefive
power of furfaces might be meafured by the weight
which was required to feparate them. About the fame
time Mr Hawkfbee proved by experiment, that the ad¬
hefion of furfaces and capillary attraction wrere not to
be afcribed to the preffure of the atmofphere, as Ber¬
nouilli had fuppofed ; but Lagrange and Cigna, after
having proved the adhefion between oil and water,
thought that it was owing to a different caufe from
that of attraction. They fuppofed that it was occafioned
by the preffure of the air, and that the opinion of Dr
Taylor was not well founded. Such were the opinions
held by philofophers on this fubjeCt, when Morveau, in
the year 1773, was led to inftitute a feries of experi¬
ments on adhefion, which he exhibited at Dijon. By
thefe experiments he proved, that this attraction was
not owing to the preflure of the air, but entirely to
the attraction of the t%vo fubftances between them-
felves. To prove this, a poliffied plate of glafs was
fufpended from the arm of a balance, and placed in
contaCt with a furface of mercury. The weight ne-
ceffary to feparate the two furfaces was equal to nine
gros and fome grains. The whole apparatus was pla¬
ced under the receiver of an air-pump, which was ex-
haufted of the air as much as poffible. It required
exaCtly the fame force to feparate the furfaces. The
fame difk of glafs brought into contaCt with pure wa¬
ter, adhered to it with a force equal to 258 grains ; but
from the furface of a folution of potaffi, it required only a
force of 210 grains. This inequality of effeCts with
equal diameters, and in the inverfe order of the re-
fpeCtive denfities, feemed not only to be decifive in
favour of Dr Taylor’s method, but appeared to point
out the poffibility of applying it to the calculation of
chemical affinities. For the force of adhefion being
neceffarily proportional to the points of contaCt, and
the fum of the points of contaCt not varying in the
adhefion of a fluid and a folid with equal furfaces, but
by
Affinity.
6t
Morveau’s
experi¬
ments.
62
Achard’s.
C H E M I
by tbe figure of tbeir conftituent parts, the difference
oftherefults points out to us precifely a caufe analogous to
that which produces affinity,the force of which it becomes
eafy, in thefe circumftances, to meafure and compare.
To afcertain the accuracy of this method, plates of
the different metals of an inch in diameter, and of equal
thicknefs, perfectly round, and well poliffied, were
procured. They were furniffied, each with a fmall
ring in the centre, to keep them fui’pended parallel to
the horizon. Each of the plates was fufpended in turn
to the arm of an affay balance, and exafUy counter-
poifed by weights in the oppofite fcale. Thus balan¬
ced, the plate was applied to the furface of mercury
in a cup, by Aiding it over the mercury in the fame
manner as is pra&ifed for filvering mirrors, to exclude
the whole of the air. Weights were then put into
the oppofite fcale, till the adhefion between the plate
and the mercury was broken. In each experiment
freffi mercury was employed. The following table ex¬
hibits the refults of thefe experiments.
S T R Y. 433
principle, made a great number of applications of it, Affinity,
which he publiffied in 1780. The refult of thefe ob- '
fervations, if accurately obtained, can alone guide us in
eftimating the points of contaft by adhefion, and by
calculating thefe points of contaft, to afcertain the fi¬
gure of the particles which touch, and the refulting 63
affinities. Three effential conditions are neceffary for Requifites.
the accuracy and uniformity of each experiment.
1. That the folid body whofe adhefion with a fluid is
to be eftimated be fo fufpended as to be in a horizontal
pofition, and that the force employed to detach it,
fiiould always aft in a line which forms a right angle
with the fur face of the fluid. 2. That there be no air
interpofed between the furface of the folid and the
fluid: and, 3. That the weights employed as a coun-
terpoife may be added, efpecially towards the end, in
very fmall quantity, not more than a quarter of a grain
each and to avoid any hidden jerk, they ffiould be
placed gently in the fcale.
The fir it point which he wiffied to afcertain was,
tbp difference of atmofoherical preffure, the
Gold adheres to mercury wdth a force equal to 446
Silver - - “ 429
Tin - - - 418
Lead - - - 397
JBifmuth - - # - 372
Zinc - 2°4
Copper - • - 142
Antimony - - - 126
Iron - - - ll5
Cobalt - - - 8
In confidering the remarkable differences, it mult ap¬
pear that the preffure of the atmofphere has no influ¬
ence, fince its effefts muff have been precifely fimilar j
nor do they depend on the difference of poliffi on the
furface-, for a plate of iron, Amply fmoothed and filed,
adheres more ftrongly than a plate of the fame diameter
W'hich has received the higheft polifti. Nor are thefe
differences owing to the difference of denfity ; for in
this cafe filver ffiould follow lead 5 cobalt w-ould ad¬
here with a greater force than zinc, and iron greater
than that of tin. On the contrary, the order of their
denfities is reverfed. What then is the order in which
the adhefion of thefe different fubftances takes place ?
It is precifely, fays Morveau, the order of affinity, or
the degrees of the greater or lefs folubility of the me¬
tals for mercury. Gold, of all the metals, attrafts
mercury molt ftrongly j but mercury diffolves neither
iron nor cobalt, and therefore they are placed at the bot¬
tom of the lift. This correfpondence, he farther ob-
ferves, cannot certainly be the effeft of chance, but
that it clearly depends on the general property of mat¬
ter called attraftion. This property which is always
the fame, and always fubjeft to the fame lawTs, pro¬
duces very different effefts, according to the different
diftances between the particles occafioned by the variety
of elementary forms 5 and that thus it may be poffible
to eftimate the force of chemical affinity by the force
of adhefion. In the prefent cafe, for inftance, the real
affinities which tend to combine mercury with gold,
filver, zinc, and copper, may be expreffed by the above
numbers 446, 429, 204, and 142.
Achard of Berlin, convinced by Morveau’s experi¬
ments, of the accuracy of Dr Taylor’s method, faw its
importance in chemiftry j and having examined the
Vol. V. Part II.
temperature remaining the fame, cauled any difference
in the adhefion of furfaces. For he found that the
adhefive force between a plate of glafs and diftilled
water was the fame at all preffures, but the uniformity
of the refults varied when he operated at different
degrees of temperature, while the elevation of the
barometer continued the fame } and he found that this
variation did not arife from the different temperatures
of the furrounding air, but from that of the water.
When the fluids are colder, the adhefion is the ftronger;
and the reafon is obvious: as they contain more matter
under the fame volume, they ought to prefent a greater
number of points of contaft in the fame fpace j and
fince the force of the adhefion is in proportion^ to the
number of the points of contaft, it ought to increafe
when the fluids are condenfed by cold, and to diminifh.
when they are rarefied by heat. Achard did not flop
by obferving thefe variations of the force of adhefion
between glafs and water heated to different tempera¬
tures ; he fubjefted them to calculation, to verify his
obfervations, and render their application eafy to all de¬
grees. The following table exhibits the force of ad¬
hefion by obfervation, and alfo by calculation. He
proceeded on the following data.
Let x be the temperature of the water, y the corre-
fponding adhefion, b its coefficient, and a the conftant
force. We have then the equation x=a—by. To
find the value of a and b, he employed two obferva¬
tions 'f the one in which water at 104° °f Sulzer’s ther¬
mometer, adhered to the glafs dilk with a force equal
to 80 grains, and the other in which water at
adhered with a force equal to 89 grains. Proceeding
from thefe two terms I04°=a—80 £
56 —a—89 by
we have a—530
9 r '
And thus the relation of the temperature ot water to
its adhefion to glafs may be thus expreffed : ^=530—
and from thence are deduced the correfponding
"9 J
values of and y for all the adhefions of glafs to water
at any temperature. Such are the data from which
and the correfponding experiments, Achard formed
3 I the
434 CHEMISTRY.
Affinity, the table which exhibits the adhefxve force of a glafs
'—“■■V"—'*' dilk of i-§-inch in diameter, to water at different tempe¬
ratures 5 and fhewing the difference of the refults.
*4
Adhefion
of glafs to
water.
65
To differ¬
ent fluids.
TABLE I.
Degrees of
Su'zer’s
Therm.
95
90
85
80
75
70
65
60
55
5°
45
40
35
3°
25
20
J5
10
Degrees of
Fahren.
Therm.
Adhefion
by Experi¬
ment.
Adhefion
found by
Calculation.
141.687
I35-9I4
i3°.X4i
124.368
118.595
112.822
107.049
101.276
95-503
89.720
83-957
78.184
72.411
66.638
60.865
55-092
49-3I9
43-546
81.25 grs
82.5
83-75
84.5
85-75
86.
87.25
88.5
89.
90.25
90-75
92.
92.75
93- 75
94- 5
95- 75
96.25
97-5
81.55
82.5
8343
84- 37
85- 3*
86.25
87.18
88.12
89.06
90.
90- 93
91- 8?
92.81
93-73
94.68
95.62
96.56
97-5
Difference.
—0.3
o
+o-34
-f 0.13
—0.46
—0.25
+ 0.07
+0.38
—0.06
-I-0.25
—0.16
+ 0.13
—0.04
-f-0.02
—0.18
+°-I3
—0.31
o
The temperature being fuppofed to continue the Affinity,
fame, if this principle be w-ell founded, the force of' v
adhefxon of any given body with water, ought not on¬
ly to increafe or diminifh according to the extent of
furface, but tbefe differences ought to be as the differ¬
ence of the furfaces.
If then p be the force with which a difk of glafs
whofe diameter is a, adheres to water, and the force
of adhefion of another difk, whofe diameter is we
bxp
fhall have the proportion a% : b* p :y andj-rr—
To verify the order of this progreffion, either with
water or other fluids, Achard employed difks of glafs
from i-J to 7 inches in diameter, having firfl afcertain-
ed their force of adhefion with thefe fluids, by the
number of grains which were neceffary to overcome it.
He afterwards calculated the fame by the above equa¬
tion. The following Table exhibits the refults of ex¬
periment and of calculation, which, if the procedure
be free from error, correfpond as nearly as could be
expe&ed.
TABLE II.
The force of adheflon between glafs difks of different diameters, and different kinds of fluids, determined by
experiment and calculation.
tnches
Dia¬
meter
of the
Difk.
1-5
i-75
2.25
2.5
2-75
3-25
3-5
3-75
6.
Diftilled
water.
Alcohol.
Experim.
grs.
364-
Calcul.
grs.
494-5 49-5
647.25 (647.
818.75 1819.
1010. ion.
1223.5
1223.
1457-
1709.
1981.5
2257.
2587.
4044.
5824-5
7926.25
!456.
1708.
1982.
2257.
2588.
4044.
5^24.
7927.
Exper.
grs.
216.
Calcul.
grs.
Liquid
ammonia.
Experim.
grs.
Calcul.
grs.
294-25 294
384- 384
457-5 457
600. 600
725. 726
328.
447. I446.
582.
738-
912.
1103.
863.25 864.
i3n-5
1015. 1014,
1177.
I35°-
1538.
2399-
3455-5
4703-
1538.25
1176.
i35o-
!536-
2400.
3456-
4704.
1786.
2049.
2332-
3645-
5248.25
7M3-
583-
738-
911.
1102.
1312.
1539-
1785.
2050.
2332-
3644.
5248.
7'43-
Solution of
potafli.
Experim.
grs.
420.
57'-
746.
Calcul.
grs
SI1-
746.
945-
945-
1167. ij 66.
1410.751 1411.
1680.5
1680.
1970.
'97 '•
2287.
2286.
2624.5 2625
2986.
2986.
4665.8 4666.
6721.
9146.
6720.
9146.
Oil of
Turpentine.
L’mfeed.
oil.
Experim.
grs.
240.
326.5
425.
539-
667.
Calcul.
grs.
Experim.
grs-
268.
326. j 363.25
426. I 475.
54=
604.
666.
744-
806.
961.
1126.5
I3°5-75
1500.
1707.
2666.
3839-5
5227.
8o6. 901.
96 c
1072.25
1126.
1259.
i3c6- [ 1458-5
1500. j 1675.25
1706. , 1905.
Calcul.
grs.
364-
476.
603.
744-
900.
1072.
1258.
1459.
1675.
1905.
2666. ! 2977.
3840. i 4289.25
5226. 5835.75
2977.
4288.
5836.
C H E M I
Affinity. Achard alfo inftituted a feries of experiments with
-v—' different folid fubftances, formed into difks of equal
diameters, and applied to the furface of different fluids.
The following table fhows the refults of thefe experi¬
ments ; but from thefe refults it appears, that the force
of adheflon does not depend on the fpecific gravity,
either of the folid or the fluid j nor does it correfpond
S T R Y. 435
with the order of chemical affinities. But befides, fome of Affinity.
the refults cannot be admitted as perfe£fly legitimate, on k---'v—*~
account of the chemical aftion which would neceifarily
take place when fome of the fubftances were brought
into contadl j as fome of the metals would be afted on
by the acids, and others by the folutions of metallic
falts.
TABLE III.
The force of adhefion of different folids, in difks 1.5 inch in diameter, whh water and other fluids, at 70"
Fahrenheit’s thermometer, determined in grains.
Fluids. <
Specific 1
gravity.
P 5
Plate-glafs
Rock eryftal
Green oriental
jafper.
Gypfum
Sulphur
Yellow wax
Ivory
Horn
Iron -
Copper -
Tin
Lead
Brafs
Zinc
TOOO.
91.
go.
80.
965
97-
90.
84.
93-5
96.5
94*5
ioc. 25
99.
96.
rs
3
1868.4
115.
112.
96.
199-75
123.
120.5
114
^ 04-75
116.
123.
129.25
124.5
55 «
is be
c %
Qj U.
o ‘Z
c ^
O nd
CJ W
1019.7
87.
86.
120.5
78.
92-5
92-75
90
8j
88.
92.
91.
98.
96.
90.25
o
-a
842.
1000.
54-
|98-
52.
96.25
46.5
58.
56.5
92.
83-75
56.
57-25
55-5
59-
59-
57-
98.75
99.8
87.25
107.
106.5
84.
76.25
104.
106.
103.5
106.25
96.
95-
88.5
85.
101.5
103.
86.
81.
98.25
102.
100.
107.
IC3-5
102.
T3
<U
•! ^
U Oh
P
I368.4
105.
IO3.
9I.
93-
110.5
111.
ll3-
106.
108.
112.
108.5
115.
114.
110.
2. 0
►4 g
1046.
82.
80.
71-
86.
88.
80.
74-5
83-5
87.
86.
3 1-
-3 «
CO
828.9
54-5
53-
85-5
48.
57-5
59-
77-5
73-
55-5
58.
54-75
91.5
90.
61.
60.
85-75 l?6-75
3 V
*■> c
-.O
O c
• ex*
o
881.5
60.
58.5
84.
52.5
64.
64.
52.
61.
62.5
61.
67.
65.
61.25
d cn
21
O R
907.8
66.
48.75
66.
56.5
56-5
69.
71.
68.
68.85
69.
72.
70.5
69.
66
Of differ¬
ent folids
to different
fluids.
From all thefe obfervations, then, tve may conclude,
that the force of adhefion between different bodies is
altogether independent of the preffure of the air ; that
it varies according to the number of points of contadl
of the touching furfacesj and that it is probably ow¬
ing to the fame caufe as the force of affinity. It ap¬
pears alfo, that the force of adhefion between folids and
fluids is in the inverfe ratio of the temperature indicat¬
ed by the thermometer, and the diredl ratio of the
fquares of their furfaces -, that different folids adhere
with different degrees of force to the fame fluid ; but
Hill it muft be allowed, that experiments and obferva¬
tions are yet wanting, to derive any advantage from
the refults of adhefive force which have been obtained,
in the calculation of chemical affinities.
Sect. II. Of the Attra&mn of Aggregation.
. 67
That force which is inherent in the particles of mat- Cohefion.
ter, by which they are held together, and form maffes,
is called coheflon ; and when particles of the fame kind
are united together, it is denominated the attraflion of
aggregation, or homogeneous affinity. It is probably
the fame in kind with that which we have already con-
3 I 2 fideredj
43^
CHEMISTRY.
Affinity, fidered, but differing in degree. Thus, it requires a
much greater force to feparate the particles of a mafs
of marble, than two polilhed furfaces of the fame iub-
■ 6s ftance brought into contact.
Difference As the force of cohefion oppofes itfelf to chemical
of force, a£Hon, fo that the chemift in his refearches is obli¬
ged to deftroy or overcome it ; it becomes a matter
of confiderable importance to be able to eftimate it.
This force is very different in different bodies. A
very great force is neceffary to overcome the power of
cohefion among the particles of an iron or gold wire,
while a fmall degree of force can feparate the particles
of a piece of wood or (tone. To afcertain this force,
experiments have been made by different philofophers,
and particularly by Mufchenbroeck, on that of the
cohefion of folid bodies. A rod of the fubftance whofe
cohefive force was to be eftimated, was fufpended per¬
pendicularly, and weights attached to the lower extre¬
mity. The rveight neceffary to deftroy the cohefive
force of the particles of matter in the rod, or to tear
it afunder, was confidered as the meafure of that force.
The following are the refults of his experiments made
on different fubftances. The fubftances employed were
rods of an inch fquare, and the numbers in the table
indicate pounds avoirdupois.
Metals.
Steel, bar
Iron, bar
Iron, caff
Copper, caff:
Silver, caff
Gold, caff
Tin, caff
Bifmuth,
Zinc,
Antimony,
Lead, caff
Alloys of Metals.
Gold 2 parts, filver I part,
Gold 5, copper t,
Silver 5, copper I,
Silver 4, tin I,
Copper 6, tin i,
Brafs,
Tin 3, lead I, - -
Tin 8, zinc I,
Tin 4, antimony I,
Lead 8, zinc I,
Tin 4, lead I, zinc I,
Woods.
Locuft tree,
Jujeb,
Beech and oak,
Orange,
Alder,
Elm,
Mulberry,
Willow,
Afli,
Plum,
Elder,
Pomegranate,
Lemon,
Tamarind,
Fir,
Walnut,
Pitch pine,
Quince,
Cyprefs,
Poplar,
Cedar,
Ivory,
Bone,
Horn,
Whalebone,
Tooth of fea-calf,
Bones.
02 CO Affinity.
8750' V
833©
8130
7656
6750
6000
5500
4880
16,270
15,250
8750
7500
4075
69
13 c,000
74>5°0
50,100
28,600
41,500
22,000
4.44°
2,900
2,600
1000
860
28,000
50,000
48,500
41,000
55>o°0
51,000
10,200
10,000
12,000
4500
13,000
20,100
18.500
i7,3o°
15,5°°
13,900
13,2o°
12.500
12,500
12,000
11,800
10,000
975©
Various opinions have been entertained of the na- Opinions ou
ture of this cohefive force. According to Newton, as1^6 nature
we have already obferved, it is properly effential to»allot c0 fc lon”
matter, and the caufe of the variety obferved in the 70
texture of different bodies. “ The particles,” fays he, Newton’s.
“ of all hard homogeneous bodies which touch one
another, cohere with a great force j to account for
which fome philofophers have recourfe to a kind of
hooked atoms, which, in effe&, is nothing elfe but to
beg the thing in queftion. Others imagine that the
particles of bodies are connefled by reft $ that is, in
effedt, by nothing at all •, and others by confpiring
motions, that is, by a relative reft among themfelves.
For myfelf, it rather appears to me, that the particles
of bodies cohere by an attraftive force, whereby they
tend mutually towards each other : which force, in the
very point of contaft, is very great 5 at little diftances
is lefs, and at a little farther diftance is quite infenfi-
ble.” V
“ If compound bodies,” Dr Defaguliers obferves,Defag.i-
“ be fo hard as by experience we find fome of them^ers‘
to be, and yet have a great many hidden pores with¬
in them, and confift of parts only laid together $
no doubt thofe fimple particles which have no pores
within them, and which were never divided into parts,
muft be vaftly harder. For fuch hard particles gather¬
ed into a mafs, cannot poffibly touch in more than a
few points j and therefore much lefs force is required
to fever them, than to break a folid particle whofe
parts touch throughout all their furfaces, without any
intermediate pores or interftices. But how fuch hard
particles only laid together, and touching only in a
few points, ftiould come to cohere fo firmly, as in fa&
we find they do, is inconceiveable 5 unlefs there be
fome caufe by which they are attra&ed and preffed to¬
gether. Now, the fmalleft particles of matter may
cohere by the ftrongeft attra&ions, and conftitute larger,
whofe attraftive force is feebler: and again, many of
thefe larger particles cohering, may conftitute others
ftill larger, whofe attra&ive force is ftill weaker 5 and
fo on for feveral fucceflions, till the progreffion end
in the largeft particles on which the operations in che-
miftry, and the colours of natural bodies, do depend 5
and which, by cohering, compofe bodies of a fenfible
magnitude.” _ . 72
A theory, which poffeffes great ingenuity and plau-i50fCovich's.
fibility, has been propofed by Bofcovich, to account
for cohefive attra&ion $ and fome fuppofe, that it is on
immaterial
!
c H E M I S
Affinity.
* Math.
Dia. 4S7.
I Wifi, of
Vifwn, vol.
i. p. 392.
73 ,
Explained.
immaterial means or powers that this attraftion, ac¬
cording to this theory, depends. Dr Hutton * feems
to think, that Dr Prieftley applies it in this view in
the following pallage, in which he attempts to lolve
fome difficulties with regard to the Newtonian doc¬
trine of light. “ The eafieft method,” fays Dr Prieft¬
ley, fpeaking of this fubjeft, “ of folving all diffi¬
culties, is to adopt the hypothecs of Mr Bofcovich,
who fuppofes that matter is not impenetrable, as has,
perhaps, been univerfally taken for granted ; but that
it conlifts of phyfical points only, endued with powers
of attraction and repulfion, in the fame manner as fo-
lid matter is generally fuppofed to be : provided, tnere-
fore, that any body move with a fufficient degree of ve¬
locity, or have a fufficient momentum to overcome any
powers of repulfion that it may meet with, it will find
no difficulty in making its way through any body what¬
ever j for nothing elfe will penetrate one another but
powers fuch as we know do in faft exift in the fame
place, and counterbalance or overrule one another.
The moft obvious difficulty, and indeed almoft the on¬
ly one, that attends this hypothefis, as it fuppoles the
mutual penetrability of matter, arifes from the idea of
the nature of matter j and the difficulty we meet with
in attempting to force two bodies into the fame place.
But it is demonftrable, that the firft obftrua.ion arifes
from no aftual contaft of matter, but from mere powers
of repulfion. This difficulty we can overcome, and
having got within one fphere of repulfion, we fa'lcy
that we are now impeded by the folid mattei itfelh
But the very fame is the opinion of the generality of
mankind, with refpeft to the firft obftruftion. Why,
therefore, may not the next be only another fphere of
repulfion, which may only require a greater force than
we can apply to overcome it, without difordering the
arrangement of the conftituent particles, but which
may be overcome by a body moving with the ama¬
zing velocity of light, f ” . „
According to the theory of Bofcovich, the firtt
elements or atoms of matter, are indivifible, unextend¬
ed, but fimple, homogeneous, and finite in. number.
They are difperfed in one immenfe fpace, m fuch a
manner, that any two or more may be diftant from
each other any affignable interval. This interval may
be indefinitely augmented or diminiffied, but cannot en¬
tirely vaniffi. Actual contaft of the atoms is therefore
impoffible, feeing that the repulfive power which pre¬
vents the entire vaniihing of the interval muft be lut-
ficient to deftroy the greateft velocities by which the
atoms tend to unite. The repulfive power muft en¬
circle every atom, muft be equal at equal dil.ances
from the atoms, and, moreover, muft increafe as the
diftance from the atoms diminiffies. On the contrary,
if the diftance from the atoms increafes, the repulfive
poxver will diminifh, and at laft will become equal to
nothing or vaniffi ; then, and not till then, an attrac¬
tive poxver commences, increafes, diminilhes, vamlhes.
But the theory does not flop here; for it fuppoles,
that a repulfive power fucceeds to the fecond or at-
traftive, increafes, diminilhes, vanifhes ■, and that there
are feveral alternations of this kind, till .at .the laft an
attraftive power prevails ; and though dimimftung len-
fiblv, as the fquares of the diftances increafe, extends
to the moft diftant regions of our fyftem. All the va¬
rieties of cohefion, Bofcovich has Ihown, may be a-
- T R Y* , 437
tisfa&orily accounted for from the diyerfity of fize, fi- ,
gure, and denfity of the cohering particles. . ?4
Bodies exift in three different ftates, which are quite iyratter in
diftind from each other ; in the folid ftate, the liquid, three ftates.
and in the ftate of elaftic fluid. Solidity, he fuppofes,
is the confequence of the irregular figure of the parti¬
cles, and their great deviation from the Ipherical form, 75
by which free motion among them is prevented.
thus, in folid bodies,the motion of one particle is followed
by that of the whole mafs ; or if the motion of the whole
mafs requires a greater force to efteft it than what is
neceffary to deftroy the cohefion of the particles, the lat¬
ter takes place. The diverfity in folids arifes from the
various degrees of force in the limits of cohefion. 76
The particles of fluid bodies, according to Boko-Fluid,
vich, are fpherical, and their forces are more direfted
to their centres than to their furfaces ; by which mo- 77
tion is freely allowed when any. force is applied.. Tm-W three
ids, he fuppofes, are of three kinds ; one in vylnch the
particles have no mutual power, as land and fine pow¬
ders ; one in which they have repulfive power; fuch
are the elaftic fluids, as air; and the third in which
they have an attraftive power, as water, mercury, 6tc.
And thefe three kinds are produced by the primary
differences in the particles which compole them. 78
There is a clafs of bodies which are intermediate Wad fub-
between the folids and fluids ; the nature of which may
be explained on the fame principles. . ftnefe are the
vifcid fubftances, the particles of which attraft each
other more ftrongly than the fluids, but not fo ftrong-
ly as the folids. In thefe bodies the particles deviate
fo far from the fpherical form, as to produce a cer¬
tain refiftance among each other, and to impede their
relative motion. . , , , 79
According to this theory, chemical phenomena may Solution,
be traced to the fame principle, namely the of
the forces and the differences in the. particles which
thence arife. Solution, for inftance, is thus explained.
The particles of fome folid bodies have a lefs attrac¬
tion for each other than for the particles of fome
fluids, and confequently when thefe. are applied to
each other, the particles of the fohd leparate, and
combine with thofe of the fluid ; and thus a mixture of
the two is formed. But the feparation or the particles
of the folid can only take place fo long. as the parti¬
cles of the fluid are in the fphere of their attraction ;
and when either of them get beyond it, or when the
attra&ion of the mixture thus formed becomes equal
to the attra&ion of the particles of the folid for each
other, no farther folution takes place, and the fluid is
faid to be faturated. But if, into this mixture, another
folid, whofe particles have a.greater attraftion lor the
fluid, be introduced, the fluid will leave the former
folid and combine with the particles of the latter..
The particles of the former will fall to the bottom, or
what is called/>ra7/>zM/7o« takes place. %a
Subftances which are diffolved, may not only be ob-Evapora-
tained again by precipitation, but alio by flowly ab-hon.
ftra&ing part of the fluid in which 'they are diflolved.
This is called evaporation, and the .folid bodies which
are thus, flowly formed, generally affume fome regular
fhape, and are denominated cryjlah. As the fluid is
removed, the particles come gradually into the fphere
of the attra&ive power of each other, and thus attain
to fome limit of cohefion, when the fluid which kept
438 C H E M I
„Affiriity- them afunder is removed. But when a folid is ob-
v tained by precipitation, the fluid is fuddenly removed
from betwixt the particles, which are confequently
left beyond the fphere of attraftion of each other, and
do not therefore aflume any regular form. And thus
it will follow, that the more flowly the procefs of eva¬
poration goes on, the more regular will be the cryftals
which are formed ; and this correfponds witlx experi-
* See Bof- ment and obfervation *.
eo-vkh's Thus, folid bodies are found, either in irregular
theory. maffes, or aflame regular forms by cryftallization j
Cryftalliza-ant* t^!e ^ame hxbftances which are capable of aflTuming
tion. " regular figures, uniformly afFedt the fame form 5 fub-
je£t, however, to certain variations from particular cir-
cumftances. No bodies can aflume the form of
cryftals, excepting fuch as can be reduced to the fluid
ftate. This, as is well known, is the ufual method of
cryftallizing falls. The fubftances to be cryftallized
are diflblved in water, which is then flowly evapora¬
ted ; and as the bulk of the fluid is diminiflied, the
particles gradually come nearer to each other, combine
together, and form cryftals. Thefe cryftals, which
are at firft fmall, receiving the addition of other par¬
ticles, become larger, and fall to the bottom by their
gravity.
Some faline bodies which are very foluble in hot
water, are diflblved but in fmall proportion in cold
water. Hot water, which is faturated with any of
thefe falls, is no longer capable of holding them in fo-
lution when it cools. The particles then gradually
approach each other, and arrange themfelves according
to certain determinate forms, or in other words, they
cryftallize. Many of the faline bodies which cryftal-
lize in this manner, when they aflume the folid form,
combine with a confiderable portion of water, which
is called the water of cryflalligation. But on the
other hand, there is another clafs of faline bodies which
aflume regular forms according to a different law. Be¬
ing equally foluble in hot and in cold water, they can¬
not be cryftallized by cooling the fluid in which they
are diflblved, but by diminilhing its quantity ; and this
is effefted by continuing the application of heat 5 that
is, by the procefs of evaporation. Salts which are
cryftallized in thefe circumftances, contain but a fmall
quantity of water of cryftallization. This is the cafe
with common fait, which is cryftallized by boiling the
fluid which holds it in folution.
Many fubftances aflume regular forms which are not
folublc in any liquid. Such, for inftance, is the cafe
with metallic fubftances, and with glafs, as well as
fome other bodies. To cryftallize fubftances of this
nature, they muft be fubjefted to fufion, and thus by
combining with caloric, they are reduced to the liquid
ftate, and the particles being feparated from each
other, are left at liberty to arrange themfelves into re¬
gular forms, or to cryftallize, and by flow and gradual
cooling, the cryftals are obtained more perfeft.
But what is the caufe that the particles of bodies,
in thefe circumftances, arrange themfelves in this man-
g2 ner ? or what is the caufe of the fame bodies in the
Accounted fame circumftances affuming regular figures ? According
for by to fome of the ancient philofophers, the elements of
bodies confifted of certain regular geometrical figures ;
but it does not appear that they employed this theory
to explain cryftallization. The regular figure of cry-
1
S T R Y.
ftals was afcribed by the fchoolmen to their fubftantial Affinity,
forms } while others fuppofed that it was owing merely *
to the aggregation of the particles, without, however,
explaining the reafon of this aggregation, or of the re¬
gular figures which it formed.
According to Newton, and the theory of Bofcovich Newton;
which we have quoted, the particles of bodies which
are held in folution by a fluid, are arranged in regular
order, and at regular diftances. When the force of co-
hefion between the particles and the fluid is diminifti-
ed, it is increafed between the particles themfelves;
they therefore feparate from the fluid, and combine to¬
gether in groups, which are compofed of the particles
neareft to each other. If it be fuppofed, that the par¬
ticles which compofe the fame body have the lame
figure, the aggregation of any determinate number of
fuch particles will produce fimilar figures. According g4
to the ingenious theory of the Abbe Hauy, the inte-byHauy,
grant particles alwrays combine in the fame body in
the fame way ; they attach themfelves together by the
fame faces or the fame edges; but thefe faces and edges
are different in different cryftals. And although the
fame fubftances are obferved to cryftallize in a great
variety of different forms, yet they all contain what
Hauy calls the primitive form, or have it within them
as a nucleus ; and this nucleus or primitive figure may S5
be extracted by careful mechanical divifion. If then 'v^° aiy
the figure of cryftals is owing to the figure of the in-cnbesltt0
tegrant particles, and to the peculiar mode of their ar¬
rangement in combination, thefe particles, when they
are left at full liberty, as is the cafe when they are
diflblved in a fluid, vrill combine in the fame wray, and
thus the cryftals of the fame body will always exhibit
fimilar forms.
In profecuting this fubjefl, Hauy found that all the the priim-
primitive forms of cryftals which he had obferved, t^ve^ormS*
might be reduced to fix; namely,
1. The parallelepiped.
2. The tetrahedron.
3. The oftahedron.
4. The regular fix-fided prifm.
5. The dodecahedron, terminated by equal rhombs.
6. The dodecahedron, with triangular faces, com¬
pofed of tw7o pyramids, united bafe to bafe.
But the nucleus or primitive form of a cryftal, he ob-
ferves, is not the laft term of its mechanical divifion. It
may be fubdivided parallel to its different faces, and
fometimes alfo in different direflions. If the nucleus
or primitive form be a parallelepiped which cannot be
fubdivided, but in a dire&ion parallel to its faces, as
takes place in carbonate of lime, it is obvious that the
integrant particle or molecule is fimilar to the nucleus
itfelf. And he has found by experiment, that the Yigml 0f
figure of the integrant particles of all cryftals may be the inte-
reduced to the three following. Thefe are, grant par-
1. The tetrahedron, or the fimpleft of all pyramids.
2. 7'he triangular prifm, or the fimpleft of all the
prifms.
3. The parallelepiped, or the fimpleft of the folids,
wrhich have their faces parallel.
From thefe primitive forms, the difference of fize,
proportion, and denfity of the different particles of
bodies, he fuppofes, may account for all the differences
of attraflion which take place in Ample aggregation
and compofition of bodies. The integrant particles
fometimes
C H E M
Affinity, foraet’raes unite by tbeir faces, and fometimes by their
' ed^es, in forming the primitive cryftals j and this
accounts for the different figures of the primitive
cryftals, which are compofed of integrant particles
of the fame form. But bodies when they are cry-
ftallized, do not always exhibit the fame primitive
form. The deviations from this, and the varieties of
88 forms which are produced, are called by Hauy fecond-
Secondary ary forms. In fome falts, for inftance, the primitive
forms form is the odftahedron 5 but in deviating from this
form, they aflume, when cryftallized, that of the cube
or the dodecahedron.
Thefe fecondary forms feem to depend fometimes
on variations in the ingredients which compofe the in¬
tegrant particles of particular bodies, the folvent in
which the cryftals are formed, or the different de¬
crements of the laminae of the cryftals. But for a full
view of this ingenious theory fee Crystallization.
Sect. III. Of the Atlraclion of Composition.
Bodies which are compofed of particles of the fame
nature cohere with a certain force, as in the particles
of water or of mercury, and thofe of wood or of me¬
tal ; and this force, we have feen, acfts with very dif¬
ferent degrees of intenfity. In the two former, the
water and the mercury, it is comparatively weak, but
s?) in the two latter it is very powerful,
explained. But the diflimilar particles of bodies alfo enter into
combination 5 and thus combined, form homogeneous
fubftances, whofe particles cohere with very great
force } and wherever thefe combinations take place,
the force of cohefion between the particles of each of
the bodies muft be deftroyed or overcome, before the
new combination can take place. Thus a piece of
marble is diffolved in muriatic acid 5 but before this
can take place, the force of cohefion which exifted be¬
tween the particles of the marble muft be overcome ;
or, in other words, the force of attradlion between the
particles of muriatic acid and the particles of the mar¬
ble is greater than that between the particles of mar¬
ble themfelves. This attraflion then which exifts be¬
tween the particles of fubftances of a different nature,
has been called the attraBion of compoftion, heterogene¬
ous affinity, or more properly chemical affinity.
This affini- This attradlion, or this affinity, does not exift be-
ty limited, tween the particles of all bodies. Thus there is no
affinity between a piece of marble and ivater, as is the
cafe between marble and muriatic acid j and it is faid
that there is no affinity between oil and water, becaufe
the particles of the one do not enter into combination
5I with thofe of the other.
Importance Chemiftry may be faid to be the hiftory of affinities,
of it. as it confifts in the detail of the numerous and various
compofitions and decompofitions which take place
among natural bodies. Without attending to the phe¬
nomena which arife from affinity, the chemift could
carry on no procefs, either of fynthefis or analyfis j
for it is by means of their affinities that the chemical
nature of bodies can be difcovered.
In taking a general view of the phenomena which
depend upon chemical attradlion, the changes or events
which are the refults of this a£lion, have been divided
into certain claffes, and from their being conftant and
I S T R Y. 439
uniform, they have been chara&erized by the name of Affinity.
laws of chemical affinity. Thefe may be confidered as '""'"v
chemical axioms which are the principles or foun¬
dation of the fcience, and therefore it is neceffary that
they fliould be well underftood, before we enter into
the detail of the fadls which it embraces.
The celebrated Fourcroy, whofe indefatigable la-Laws,
hours and extenfive views in chemical fcience will al¬
ways be admired and valued, has arranged the fadls
which depend on chemical affinity under ten different
heads, which he has denominated the laws of affinity.
In illuftrating this interefting part of chemical fcience,
we fliall obferve the fame arrangement.
92
First Law.
93
Chemical affinity takes place only between bodies of a Affinity
different nature, or between diffimilar particles. between
This law, when confidered as a law of chemical
finity, may be regarded as negative j for when the par-1
tides of bodies of the fame nature combine together,
it is by the force of cohefion, and therefore comes
under that fpecies of affinity called the attraftion of
aggregation. No chemical aftion has taken place,
no new compound is formed j which are the charac-
teriftics of chemical affinity.
But as an inftance of the effedl of chemical affinity
between two bodies of a different nature, we may re¬
fer to the experiment above alluded to, of the combina¬
tion which takes place between a piece of marble and
muriatic acid j for by the mutual adion between thefe
two bodies the marble has difappeared, and the acid
has totally changed its properties. The compound,
which is the refult of this combination, proves that
the heterogeneous bodies have entered into intimate
union with each other.
Chemical affinity may ad between two bodies, and
a combination take place, when thefe bodies are totally
uncombined wdth all others. In this cafe the combi¬
nation is produced by the force of affinity between the
two bodies; but when one or both of thefe bodies is
in a ftate of combination with others, the bodies which
are faid to have the greater affinity for each other, do
not entirely combine together, and leave the bodies with
wffiich they w’ere firft in combination. Suppofe A and B
are two bodies which have an affinity for each other, and
are in a ftate of combination ; and fuppofe C is a third
body which has a ftronger affinity for the body B than,
the affinity which exifts between A and B. Now,
the body C having a greater affinity for the body B
than what exifts between the compound body AB
when it is brought into circumftances where the
force of that affinity can be exerted, the compound
body AB will be decompofed, that is, the body C
will combine with the body B, and will leave the
body A. It was formerly fuppofed by chemical phi-
lofophers, that this decompofition was complete ; that
is, as in the cafe ftated above, the affinity between C
and B being greater than the affinity between A and
B, the body C, when in fufficient quantity, abftrafted
every particle of the body B from its combination
with the body A. But the experiments and obferva-
tions of the fagacious Berthollet have placed this mat¬
ter in a new light. This will be bcft illuftrated by
detailing fome of the experiments by which this inge¬
nious
440
Affinity.
94
Examples.
C H E M I
*■ Refear-
ehes, Tranjl.
95
Affinity in.
creafed by
the mafs.
nious philofopher has clearly afcertained many curious
fadls with regard to chemical affinity (d).
The fulphuric acid has a very ftrong affinity for the
earth called barytes, forming with it a compound
which is infoluble either in hot or cold water. Sul¬
phuric acid alfo has an affinity for potafh, but it is
much weaker than that which exifls between the acid
and barytes *, yet the potafh, although pofTefled of the
weaker affinity, abftraas part of the fulphuric acid
from the barytes, and combines with it. This is
proved by Berthollet in the following experiment.
1. He took equal quantities of pure potafh, and
fulphate of barytes (e), and boiled them together in a
fmall quantity of water. According to the views of
former chemifts with regard to chemical affinity, no
decompofition fhould take place, becaufe the affinity
between the fulphuric acid and the barytes was flrong-
er than that between the acid and the potafh. But
from the refult of this experiment it appears, that the
fulphate of barytes was partially decompofed by the
potafh, and that the fulphuric acid was divrded be¬
tween the two bafes j that is, between the barytes and
the potafh. ...
2. The oxalic acid has a greater affinity for lime than
for potafh j but if oxalate of lime, that is oxalic acid
combined with lime, be boiled along with potafh in a
fmall quantity of water in the proportion of one part
of the oxalate of lime to two of the potafh, a partial de¬
compofition of the oxalate of lime will take place, part
of the oxalic acid is abflradled from the lime, and com¬
bines with the potafh *.
3. One part of phofphate of lime was boiled toge¬
ther in a fmall quantity of water with two parts of pot¬
afh. The phofphoric acid has a greater affinity for
lime than for potafh j but from this experiment it ap¬
peared that the phofphate of lime was partially decoin-
pofed, and part of the phofphoric acid having combin¬
ed with the potafh, formed the new compound, phof¬
phate of potafh.
From thefe experiments Berthollet obferves, that
the bafes which are fuppofed to form the flrongefl
combinations with the acids may be feparated from
them by others whofe affinities are fuppofed to be
weaker, and that the acid divides itfelf between the
two bafes. Where a fmall quantity only of the de-
compofing fubftance is employed, the effedl is not per¬
ceptible ; but if a large quantity be employed, as in one
of the above experiments, if the fulphate of barytes
had been treated with fucceffive portions of potafh, it
would have been ultimately and almoft entirely decom¬
pofed ; for the weaker affinity of any body is made
up by increafing the quantity of that body.
Bergman has remarked, that if fix times as much of
the decompofing fubftance be employed as is fufficient
to faturate the bafe, a decompofition will be effefted
which may be confidered as total, becaufe the oppofing
fubftance retains fo fmall a part of that with which it
S T R Y.
was combined, that it may efcape the obferver’s notice, Affinity,
and be confidered as an evanefcent quantity. But the
above experiments fhew, that a fimilar decompofition
could be produced, if the reverfe of the experiment
which Bergman recommends had been attempted.
When one fubftance afts on another in combination
with a third, the fubject of combination divides itfelf
between the two others, not only in proportion to the
energy of their refpeftive affinities, but alfo in pro¬
portion to their quantities. The two iubftances which
aft on the combination may be confidered as oppo¬
fing forces afting on the fubjeft of combination, and
{haring it between them in proportion to the inten-
fity of their aftion j and this intenfity may be efti-
mated by the quantity of the fubftance and the energy
of its affinity. The effeft, therefore, muft increafe or
diminifti as the quantity increafes or diminiflies. Thus
it appears that eleftive affinity in general dots not aft
as a determinate force by which one body can com¬
pletely fe par ate another from a combination j but
that in all compofitions and decompofitions produced
by affinity, there is a partition of the fubjeft of the
combination between the two bodies, the energy ot
whofe affinities is oppofed, and the proportions of this
partition depend not folely on the difference of energy
in the affinities, but alfo on the difference of the quan¬
tities of the bodies •, for it has been obferved that an
excefs of the quantity of the body whofe affinity is the
wTeaker, compenfates for the weaknefs of affinity.
Second Law.
96
Chemical affinity takes place only between the ulti- Affinity
mate particles of bodies. # . between
The attraftion of aggregation or cohefion which is^e ui i-
exerted between the integrant particles 01 bodies, jsj.jc]e3.
oppofed to the aftion of chemical affinity. For, as in
the cafe juft mentioned, of the combination that takes
place between a piece of marble and muriatic acid, the
force of cohefion betwreen the particles of the marble
muft be overcome before chemical aftion begins, and
a new compound can be formed, d he new compound
confifts of the conftituent particles of the two bodies,
which are now intimately united by the force of affini¬
ty which exifts between them.
Third Law.
Chemical affinity takes place between feveral bodies. * Between
It is not merely compounds confifting of the parti-feveral bo¬
des of two bodies, that are formed by chemical affini-dies.
ty, for we fliall find that there are numerous inftances
of three or four fubftances entering into chemical com¬
bination. Alum, a well known fubftance, is a com¬
pound of three fubftances which have entered intp che¬
mical union. Thefe are, fulphuric acid, alumina or
pure clay, and potaffi. d he fame thing happens alfo
in all thofe compounds which are called triple falts,
which confift, like alum, of three different fubftances j
but
(d) The reader, it is hoped, will find no difficulty in underftanding the general reafonmgs on this fubjeft j
but he will be able to comprehend it fully, after the fubftances whofe affinities are given as examples, are treated
of in detail in their proper places. . . , .1 . a,*
(e) This is the compound of fulphuric acid and barytes, according to the new chemical nomenclatu ,
principles of which will be afterwards explained.
Affinity.
98
Alloy of
metals.
99
One body
muft be
fluid.
100
Effedl of
folubility.
C H E M I
but tbe moll remarkable inftances of tbe effedts of
chemical affinity on feveral bodies are obferved in the
alloys of fome of the metals. The temperature at
which the metals are fufed is generally pretty high,
but an alloy of fome of them may be brought to a ftate
of fufion at a low temperature. This is the cafe with
the alloy of bifmuth, lead, and tin, which may be
melted at the temperature of boiling water, which is
far below the fufing point of any of the uncombined
metals, and ffiews by this change of their properties,
that a chemical union has been effefted.
Fourth Law.
tThat chemical affinity may take place between two
bodies, it is necejfary that one of them be in the liquid or
fuid fate.
The folution of a folid body in a fluid, may be con-
fidered as the deftrudlion of the cohefion of its parti¬
cles, and their equal diffufion in that fluid. It is the
combination of the particles of the folid with thofe of
the fluid •, and the compound ftill poffefies the charac-
teriftic phyfical properties of the fluid. Thus, in the
firfl place, the force of cohefion between the particles
of a folid body is deftroyed, by its folution in a fluid j
which force mull always be overcome before a new
compound can be formed by the aftion of chemical af¬
finity. But, zdly, The particles of a body diflblved
in a fluid are in their ultimate, or at leaft very minute,
ftate of divifion j by which means the points of contact
between the particles of the body held in folution,
and thofe of any other with which it may combine,
are greatly multiplied } and thus the operation of che¬
mical action between thefe particles is greatly extended.
Many familiar procefles are examples of the effe£ls of
folution, as fugar diflblved in water’, common fait in the
fame fluidor the experiment mentioned above, of mar¬
ble in muriatic acid. In the procefs of making glafs
we have another example of the fame nature. The
two fubftances which enter into the compofition of
glafs are in the folid ftate. Thefe are filiceous earth
or fand, and an alkali. But to effea the combination
of the two folids, one of them is brought to the fluid
ftate by the application of heat. The alkali firft melts,
and in the ftate of fufion the fand or filiceous earth
combines wfith it, and forms an uniform compound,
which is glafs.
But Berthollet has ffiewn, that the folubility of
bodies has a very great influence in modifying the
aftion of chemical affinity. For he obferves, when a
body is in fome degree foluble, its a61ion is compofed
of that of the part difiblved and of that of the part
which has retained its folidity. It follows that its
aftion does not increafe in proportion to the quantity
employed. Lime, for inftance, ads by the part dif-
folved, and by that which remains folid ; but it is
probably the diffolved part which contributes princi¬
pally to the efifed produced. If the quantity of lime
employed in an experiment be doubled, without in-
creafing the quantity of the liquid, the quantity of
lime diflblved will rather be diminiffied than increafed,
becaufe a part of the liquid is abforbed by the lime
which has been added.
If an infoluble combination can become foluble by
being deprived of a part of its compofition, the incon¬
venience of infolubility is eafily removed. 1 hus it is,
Vol. V. Part II.
S T R Y. 441
when the phofphate of lime is aded on by an acid. Afflmt)-. ^
The part of it which is within the fphere of adion is v
inftantly converted into an acidulous, phofphate, and ,
the other part fucceffively, until both the oppofed fub¬
ftances be reduced to a liquid ftate.
“ When an eliminated fubftance becomes infoluble,
the precipitate which is formed retains a portion of the
fubftance with which it was combined, in proportion
to the individual forces which aded in the moment of
the precipitation. The operation is no farther in¬
fluenced by this portion, lb that the quantity of the
precipitating body adequate to the precipitation is all
that is neceflfary until the end of the operation. But
the cafe is different when the eliminated fubftance af-
fumes the liquid ftate, for then the refiftance increafes
according to the progrefs of the decompofition ; and
hence it follows, if a fubftance nearly infoluble be
oppofed to a combination, and its adion be confe-
quently only partial, whilft the fubftance eliminated
remains liquid, that the decompofition muft be quickly
flopped, whatever may be the force of the affinities.
Becaufe it has been already ffiewn that the decompof-
ing adion depends not merely on the affinities, but al-
fo on the relative quantities in adion. When the ful-
phate of potaffi was decompofed by means of lime, the
operation was neceffarily flopped as foon as the ful-
phuric acid w’as entirely divided between the potaffi
and lime, in proportion to their refpedive affinities,
and to the quantity of each which had aded on the m Berthol_
fulphuric acid j that is, in proportion t© their refpedive " '
maffes” *. fearches.
But fluids in the elaftic ftate, or the flate of gas, art. 4.
produce effeds which are contrary to thofe of the force 101
of cohefion j and thus modify in a different manner Elaftic
the effeds of the particular affinity of each fubftance.flulds’
Elafticity ads, either by the removal of fome fubftances
from the adion of others, or by diminiffiing their pro¬
portion within the fphere of adion. But if all the
fubftances in adion be in the elaftic ftate, this effed
will not follow, becaufe then they all exift in a fimilar
condition. When a fubftance on feparating from an
intimate combination, affumes the ftate of gas, it be¬
comes elaftic, and then it can oppofe no further refif-
tance to the decompofing adion. And thus it appears
that fubftances of this nature do not ad by their mafs.
A complete decompofition can then be efteded by the
decompofing fubftance, and no greater quantity of it ■
is required than what w’ould have been neceffary to
form the compound by dired combination. Thus,
carbonic acid, which is an elaftic fluid, may be dif-
engaged from its combination by another fubftance
whofe affinity for the bafe may be lefs, becaufe that
other fubftance can ad by its mafs, and can therefore
overcome the affinity of the carbonic acid by its fuc-
ceffive adion. But if the whole of the carbonic acid
is to be expelled, the decompofing fubftance muft; be
ufed in greater quantity than what is juft neceffary to
produce faturation. 102
The adion which takes place wffien concentrated Example,
fulphuric acid is poured on dry common fait, that is,
both fubftances being as much as poffible deprived of
water, affords a good illuftration of the effed of the
elafticity of one of the fubftances. Common fait, is
compofed of muriatic acid and foda. I he affinity
of the fulphuric acid for foda is greater than that
3 K of
442 C H E M
Affinity, of muriatic acid. When, therefore, the fulphuric acid
< js poured on the common fait, it combines with the
foda, and the affinity of the muriatic acid is dimi-
niffied. It confequently affumes the gafeous hate,
and afts no longer by its mafs. But if a folution of
common fait in water be employed, or a diluted acid,
then the muriatic acid may be retained in the water,
and in this cafe it can a& by its mafs.
When, therefore, a fubftance is in the hate of gas,
its elafticity is to be corffidered as a force oppofed to
the affinity of liquid fubffiances. When the elafticity
of gafeous fubftances is dimxniflied, as happens by com-
preffion, they then combine in greater quantity with
liquids. When water is brought into contact with
carbonic acid, which is in the ftate of gas, it does not
become faturated with that acid, becaule the elafticity
of the gafeous acid oppofes the difi'olving power of
the water: and before its diffolving force is exhaulted,
the two forces are balanced. But when the oppofing
elaftic force is diminilhed, as by compreffion, the dif-
folving power of the water continues its aftion, and
thus it is more fully faturated with the acid.
Fifth Law.
I03
Change of When bodies combine together, they undergo a change
tempera- of temperature.
In all bodies there exifts a certain quantity of calo¬
ric, or the matter of heat; but when any change takes
place In the nature or conftitution of any body, its
power of retaining that portion of caloric is alfo
changed. During thefe changes heat is either given
out or abforbed ; and this increafe or diminution of
temperature becomes obvious t® our fenfes, or may be
meafured by the thermometer.
The effeifts of this variation of temperature will be
greater or lefs, in promoting or retarding the aftion of
chemical affinity, according to the change which takes
place on the fubftances which are decompofed, or ac¬
cording to the ftate of the compound which is formed.
When there is a great elevation of temperature, in con-
fequence of the heat produced by the combination of
fubftances, it is neceffary to attend to the difference of
volatility of which the fubftances are fufceptible by
that elevation of temperature. If the fubftances are
not all in the liquid ftate, or if one of them only be
foluble, the effedt of heat is to favour their mutual
adlion; becaufe the force of cohefion, which afts even
between the particles of bodies in the liquid ftate, is
thus diminilhed. If the expanfion by heat of the one
of two fubftances be greater than that of the other,
the more expanded fubftance acquires a greater degree
of elafticity, and this, as has been already obferved,
muft be confidered as a force oppofmg the affinity
which exifted between the two bodies.
In chemical combinations, according to this lawq
the temperature changes, and it is either increafed
or diminiffied, according to the nature of the com¬
bination which is effe&ed. This will be bell illuftrated
io^ by an example or two.
Examples. I* When lime is flacked, that is, when water is
thrown upon burnt lime, a great elevation of tempera-
I S T R Y.
ture takes place. The water enters into combination Affinity,
with the lime ; it paffes from the fluid to the folid >
ftate; and, during this change, a great quantity of ca¬
loric, or the matter of heat, is given out, which is
the caufe of the increafe of temperature (f).
2. As an example of two fluids when mixed toge¬
ther producing a fimilar effefl, take four parts of con¬
centrated fulphuric acid, and pour it on one part of
water; the temperature of the combined fluids will be
elevated to the boiling point of water.
In the folution of folid bodies in a fluid, there is
a great change of temperature ; but in this cafe it is
diminilhed. This is particularly the cafe when falts
are diffolved in water.
1. Take muriate of ammonia, or fal ammoniac, and
diffolve it in water, and while the folution is going on,
if a thermometer be plunged into it, there will be a
confiderable fall of the mercury in confequence of the
abforption of caloric, or the diminution of tempera¬
ture.
2. If one part of water, at the temperature of 50°
or 6o° of Fahrenheit, be poured on an equal quantity
of ice, the temperature of the water will be diminilhed
to the freezing point, or 3 2°.
3. A very low temperature is produced by a mix¬
ture of ice and common fait; and a Hill lower by a mix¬
ture of fnow and powdered muriate of lime. But we
lhall become better acquainted with the effedls of thefe
fubftances in explaining the method of producing arti¬
ficial cold.
Sixth Law.
The compounds formed by chemical affinity pojfefs new Compounds
properties, and different from thofe of their conJhtucnt\\sve new
parts. ' properties.
We are too little acquainted with the nature of che¬
mical affinity, to be able to determine, a priori, what is
to be the refult of a combination between tivo fubftances.
No information can be obtained what the nature of the
union will be, from knowing the properties of the fub¬
ftances which are to be combined. It is only by ex¬
periment that the nature and properties of the new
compound can be afeertained.
Unwilling to fuppofe, or unable to conceive, that
the properties of the trvo fubftances which enter into
combination, had totally difappeared in the new com¬
pound, the earlier chemifts imagined that the proper¬
ties of the latter were of a middle nature, confifting
of the mixed properties of the compofing fubftances.
Hence the compounds of the acids and the alkalies
were denominated middle falts, fales medu, from pof-
feffing the combined properties of their component fub¬
ftances.
But the truth of this dodlrine, with regard to the
nature of compound fubftances, has been fully dif-
proved by the more accurate obfervations of mo¬
dern chemifts; for it is found by experiment that
the compound formed exhibits not a fingle property of
any of the fubftances of which it is compofed. On
the contrary, of tv.To mild and infipid fubftances, a
compound is formed which is highly acrid and corro-
five ;
(f) Tue explanation of this phenomenon will be given, when we come to treat of heat.
C II E M I
Affinity, five ; and die refult of die combination of two power-
fully corrofive i’ubftances, is frequently a mild and in-
fipid compound.
It is indeed one of the charafteriflics of chemical
affinity, that there be a total change in the proper¬
ties of the fubftances which enter into combination.
This change takes place in the fenfible qualities of
many of the compounds, and fome of thefe, as an illuf-
tration of this law, may be mentioned.
(i.) Changes of colour. The colour of lead is a
bluiffi white, but when it combines with oxygen it af-
fumes a bright yellow or red colour, in proportion to
the quantity of oxygen. Cobalt, which is of a gray
colour, when combined with oxygen, becomes of a
fine blue ; and copper, which is red, combined in the
fame way, exhibits a green colour.
(2.) Changes in fmell. x. The fmell of muriatic acid
is highly pungent *, ammonia, or the volatile alkali, is
not lefs fo ; but when thefe two are combined, form¬
ing muriate of ammonia, or fal ammoniac, the new
compound is perfeftly inodorous. This laft is a re¬
markable inftance of two highly volatile and odorous
fubftances becoming fixed in the compound, and defti-
tute of fmell, and thus exhibiting a total change of
their properties.
2. The fmell of fulphur and of potaflr is fcarcely
perceptible in the uncombined ftate *, but when they
are united together, and moiftened with water, a moft
foetid and offenfive odour is emitted.
(3.) Changes in tafte. 1. The tafte of fulphur is near¬
ly infipid ; and oxygen, which is one of the component
parts of the atmofphere, is not only innocent, but ne-
ceffary for the exiftence of animals: but when thefe
two enter into union, the compound formed, which is
fulphuric acid, is one of the moft corrofive fubftances.
2. Sulphuric acid, which is four and corrofive, forms
a combination with foda, which is alfo of a corrofive
nature; the refult, which is Glauber fait, or fulphate
of foda, is a compound of a bitter, naufeous tafte,
but poffefting none of the properties of its component
parts.
Seventh Law.
ictf . , .
Force of 'The force of chemical affinity, is efimated by the force
affinity which is neceffary to feparatc the fubjlances which enter
into combination.
In treating of cohefion, or the attradlion of aggre¬
gation, it was ftated, that the method employed by
philofophers to eftimate that force, was to meafure the
oppofite force, or that which was neceffary to over¬
come the cohefive force. Thus, the weight attached
to the lower extremity of a metallic wire perpendicu¬
larly fhfpended, which was juft fufficient to tear it a-
funder, is confidered as the meafure of its power of
cohefion. But it will appear from what follows that
this law muft be adopted with confiderable modifica-
107 tion-
eftimated In eftimating the force of chemical affinity, various
by the time methods have been propofed by different philofopbical
of folution; cliemifts. It was thought by Wenzel, that the time
which one body required to diffolve another, might be
confidered as the meafure of the force of affinity be¬
tween thefe two bodies ; but it muft appear from what
has been already faid, that the time of folution muft
depend greatly on the cohefive force of the body
S T R Y. 443
which is to be diffolved, and the nature of the com- Affinity,
pound which is formed ; fo that from thefe deviations, v *
no certain meafure can be obtained from this method. icS
According to fome, the meafure of the forex of che- jT t^e^“
mical affinity may be eftimated by the difficulty of fe-feparation;
parating the fubftances which have entered into com¬
bination ; or, by taking the compound ratio of the fa¬
cility with which they are combined. But as no me¬
thod has been invented to afeertain either the one or
the other, which are the neceffary previous fteps in
the method propofed, it is impoffible, in this way, to
eftimate the force of chemical affinities. top
Obferving the effedls of the union and abftraflion of by the af-
caloric, in the operations of chemical affinity, Lavoi-
fier and La Place, in a memoir publiftied in 1783, ‘ ‘
propofed this as the method of eftimating the force of
affinity. But it feems fcarcely poffible to meafure the
force of chemical affinity between two fubftances by
the degree of temperature which is required to over¬
come the force of cohefion ; or, as this degree of tem¬
perature has no meafurable proportion with the force
of chemical affinity, it can afford no data for eftima¬
ting this force. And this quantity being variable and
unknown, a fixed term is wanting to form a fcale of
companion.
We have already mentioned, in treating of adhefion,
the experiments of Dr Taylor on the adhefion of fur-
faces, and the experiments and conclufions of Morveau
and Achard on the fame fubjeft. From thefe Mor¬
veau has propofed to deduce a method of eftimating
the force of chemical affinities. But lor an account
of this, we refer the reader to the firft feftion. no
A different method has been propofed by Mr Kir-Kirwan’s
wan, in his experiments and obfervations on the at-11161*10^’
tra&ive powers of mineral acids*. He obferves, * A’/SiA
that the principal end which he had “ in view '^rayf-v0^’
was, to afeertain and meafure the degrees of affinity XXU1‘
or attraction that fubfift between the mineral acids,
and the various bafes with which they may be combi¬
ned ; a fubjeft of the greateft importance, as it is up¬
on this foundation that chemiftry, confidered as a
fcience, muft finally reft ; and though much has been
already done, and many general obfervations laid down
on this head, yet fo many exceptions have occurred,
even to fuch of thefe obfervations as feem to have been
moft firmly eftablifhed, that not only a variety of ta¬
bles of affinity have been formed, but many very e-
minent chemifts have been induced to doubt whether
any general law whatfoever could be traced” f. \Ihid.y 34.
“ The difeovery of the quantity of real acid in each
of the mineral acid liquors, and the proportion of
real acid taken up by a given quantity of each balis
at the point of faturation, led me unexpectedly to what
feems to me the true method of inveftigating the quan¬
tity of attraction which each acid bears to the feveral
bales to which it is capable of uniting. For it was
impoffible not to perceive,
I ft, That the quantity of real acid neceffary to fa-
turate a given weight of each bale, is inverfely as the
affinity of each bafe to fuch acid.
zdly, That the quantity of each bafe requifite to
faturate a given quantity of each acid, is direCtly as
the affinity of fuch acid to each bafe.
Thus, 100 grs. of each of the acids require for their
faturation, a greater quantity of fixed alkali than of
3 K 2 calcareous
444 C H E M
Affinity, calcareous earths, more of this earth than of volatile
alkali, more of this alkali than of magnefia, and more
I S T R Y.
of magnefia, than of earth of alum; as may be feen Affinity,
in the following table.
Quantity of bafe taken up by 100 grs. of each of the three acids.
Sulphuric acid.
Nitric acid.
Muriatic acid.
Potafli.
grs.
215
215
215
Soda.
grs.
165
165
158
Lime.
grs.
IIO
96
89
Ammonia
grs.
90
87
79
Magneiia.
grs.
80
75
7i
Alum.
grs.
75
65
55
“ As thefe numbers,” Mr Kirwan obferves, “ agree
with what common experience teaches us concerning
the affinity of thefe acids with their refpe&ive bafes,
they may be conlidered as adequate expreffions of the
quantity of that affinity. Thus, the affinity of the
fulphuric acid to potaih, that is, the force with which
they unite to each other, is to the affinity with which
that fame acid unites to lime, as 215 grs. to 110 ; and
to that which the nitric acid bears to lime, as 215 to
in 9^-”
Objedtions. But to this method of Mr Kirwan obje£hons
have been made by Morveau and Berthollet. It is
ftated that the effiential principle of the force of affi¬
nity being in the direft ratio to the quantity of bafe,
is not fully eftabliffied. According to the experiments
of Morveau, a quantity of fulphuric acid containing
100 grs. of real acid, required for faturation 201 grs.
of cryftallized carbonate of potaffi: a quantity of nitric
acid which contained 100 grs. of real acid, required
302 grs. for faturation j and a quantity of muriatic acid
containing 100. grs of real acid, required no lefs than
905 grs. of the fame fait for faturation. From thefe
experiments it appears, that Mr Kirwan’s calculations
are erroneous, or that the principle on which he has pro¬
ceeded is falfe 5 for equal quantities of real acids re¬
quire for faturation different quantities of potaffi 5 and
befides, the quantity of bafe required is in the inverfe
ratio to the force of affinity, which is the reverfe of
Mr Kinvan’s principle.
Mr Kirwan, however, has acknowledged the force
of thefe obj eft ions, and has deduced theproportion of
real acid in the nitric and fulphuric acids, from lefs
exceptionable principles. His table, therefore, which
expreffes in numbers the ftrength of affinities, is confi-
dered as the moft correft which has yet been publiffi-
ed; and his general principle, that the quantity of bafe
required to faturate a given quantity of real acid, is
the expreffion of the force of affinity between the acid
and the bafe, feems to receive additional confirma¬
tion in proportion to the progrefs of chemical know-
ledge.
Mr Kirwan has correfted the quantity of bafe taken
ters.
xoopts.
Sulphuric.
Nitric.
Muriatic.
Carbonic.
Potafli.
I 21.48
117.7
177.6
95.1
Soda.
78.32
7343
!36.2
149.6
Ammonia.
26.05
40-35
58.48
Barytes.
200.
178.12
314.46
354-5
Strontites.
i38.
116.86
2l6.2T
231--r
Lime
7°.
55-7
118.3
122.
Magnefia.
57.92
47-64
89.8
50.
But according to the experiments and obfervations
of Berthollet, as the force of affinity varies in propor¬
tion to the mafs of any body, no method, however ac¬
curate in other refpefts, will afford a certain rule for
eftimating the force of chemical affinity.
Eighth Law.
Different Bodies have different degrees of affinity for each other.
affinities On the different force of affinity which exifts be-
among tween different bodies, depend many of the moft im-
boches. portant operations in chemiftry} and it is by multiply¬
ing the objefts of this law, that chemical fcience can
be improved and extended.
Two kinds. Affinities have been divided into two kinds, Jimple
affinity, and compound affinity ; or fimple eleftive at-
traftions, and double eleftive attraftions.
T 114 • Simple affinity.—The firft of thefe includes all thofe
twoToffies. combinations which direftly take place between two
bodies, as when muriatic acid and lime are combined
together. It is alfo a cafe of fimple affinity, or fingle
eleftive attraction, when to a folution which contains
two fubftances, there is added a third which produces
the feparation of one of the diffolved bodies. This
takes place when potaflr is added to the folution of
lime in muriatic acid. The potafh has a ftronger affinity
for the muriatic acid than the lime ; it therefore fe-
parates the acid from the lime, combines with it, and
remains in the folution. The lime thus feparated from
its combination, appears in the folid form, and falls to
the bottom. This is called a precipitate. . II5
In oraftical chemiftry precipitates are diftinguiftied Precipi-
into feveral kinds. It is faid to be a real or true pre- tates.
cipitate when the body which is difengaged from the
combination falls to the bottom, as in the cafe above
where the lime fell to the bottom, after being feparated
from the muriatic acid. A falfe precipitate is when
the new compound which is formed falls down, as
when fulphuric acid is added to any folution of lime 5
for the compound being infoluble, it appears in the
form of a precipitate. A precipitate is faid to be pure
wdren the body which has been decompofed, can be formed
again from the feparated conftituent parts j and impure
° when
C H E M
Affinity, when this cannot be effe&ed 3 that is, probably, when
'—■ v ‘ the decompolkion has not been complete. It fome-
times happens when a body which confifts of two fub-
ftances, is decompofed by means of a third, that the dil-
engaged fubftance affumes the elaftic form. This is
the cafe when muriate of ammonia is decompofed .by
quicklime. The muriatic acid which is in combination
with the ammonia, unites with the lime for which it has
the greater attra&ion*, and the ammonia is fet free, and
TI6 is inftantly volatilized.
Between Compound affinity.—But there are fubftances. which
more than cannot be decompofed when a third fubftance is pre-
two’ fented. The affinity of the two fubftances A and B
in combination, may be fo much ftronger than the af¬
finity of a third C for either A or B, that no decom-
pofition will take place when the body C is prefented
to the compound of A and B. Suppofe the two fub¬
ftances A and B are held united with a force equal to
12, and the force of affinity between the body C and
B is equal only to 8, it is obvious that no change can
be effeaed, becaufe the force of affinity between C and
B cannot overcome the cohefive force that exifts be¬
tween A and B. But if a fourth body D is prefented
to the compound A and B, and aas with a force on the
body A equal to 6, while the body C aas on B with a
force equal to 8, it is evident that the combined act!on
of thefe two forces will overcome the force of affinity
between A and B, which was fuppofed to be equal to
12, becaufe the meafure of a force equal to 14 is great¬
er than one equal to 12 3 and in this wray the decom-
pofition of the body A and B is effeaed by the united
aaion of two other bodies which would not have fuc-
ceeded, had any one been prefented toitfingly. Irom
this double aaion a decompofition of this kind is cal¬
led a double eledive attraBion, a name given by Berg¬
man, or a cafe of compound or complex affinity, as it
ffias been propofed to be denominated by later chemifts.
Bergman invented a method of exhibiting thele at-
traaions, as in the following diagram.
Nitrate of Potafli.
Sulphate
of potafti
Potafti.
Sulphuric
acid.
Nitric acid.
Oxide of
filver.
Nitrate
of filver.
Sulphate of filver.
In this example the fubftances to be decompofed are
placed on the right and left fides of the diagram. Thele
are the fulphate of potaffi compofed of fulphuric acid,
and potaffi on the left fide 3. and the nitrate of filver,
which confifts of nitric acid and the oxide of filvtr.
When thefe compounds are combined together, a de¬
compofition is effeded by the mutual affinities between
the conftituent parts of the compounds. Thus the ful¬
phuric acid in combination with the potaffi, forms a
new compound with the oxide of filver 3 and the ni¬
tric acid in combination with the filver,^ forms a
nerv compound with the potaln 3 becaufe tne fum o
the force of affinities between the nitric acid and the po¬
taffi, and the fulphuric acid and the oxide of filver,
is greater than the fum of the affinities between
I S T R Y.
445
the fiilphuric acid and the potafti, and the nitric acid Affinity,
and the oxide of filver ; and thus an exchange of prin-
ciples takes place, and the new compounds are repre-
fented at the top and bottom of the diagram, namely the
nitrate of potafti and the fulphate of filver.
Mr Elliot in the year 1782 propofed, as an improve¬
ment on Bergman’s method, to reprefent the force of
thefe attractions by numbers. The fame cafe in Mr
Elliot’s method is reprefented in the following dia¬
gram.
Nitrate of potafti.
Sulphate
of potaffi.
Potaffi.
Sulphuric
acid.
8 Nitric acid.
Oxide of
filver.
Nitrate
of filver.
Sulphate of filver.
As it is thus reprefented, the fulphuric acid and the
potafti are fuppofed to aft with a force equal to 9 3 and
the nitric acid and the oxide of filver attraft with a
force equal to 2. The affinity of the potaffi for the
nitric acid is equal to 8 ; and the affinity between the
fulphuric acid and the oxide of filver is equal to 4*
But 9+2=11, and 8 + 4=12, confequently the fum
of the affinities between the nitric acid and the potaffi,
and the fulphuric acid and the oxide of filver, exceeds
the fum of the affinities between the nitric acid and the
oxide of filver, and the fulphuric acid and the potafli,
and thus a decompofition is effefted. ny"
But “ in all decompofitions,” fays Mr Kirwan, “ we Two forces
muft confider, firft, the powers which refill any decom-
pofition, and tend to keep the bodies in their prefent 1 u
ftate 3 and 2dly, the powers which tend to effeft a de¬
compofition and a new union. The fiilt I ffiall call
quiefcent affinities, and the fecond, divellent.
“ A decompofition wull always take place when the
fum of the divellent affinities is greater than that of the
quiefcent 3 and on the contrary no decompofiti.on will
happen when the fum of the quiefcent affinities is fupe-
rior to, or equal to that of the divellent : all we have
to do, therefore, is to compare the fums of each of thefe
powers. Thus, if the folutions of fulphate of potafli
and nitrate of lime be mixed together, a double de¬
compofition wall take place” * I his may be illuftra-
ted by the following diagram.
Nitrate of potafli.
co
nT
B-
Potaffi.
215
+
o
Nitric
acid.
215 + Quicfcent 2- affinities 96=311.
Sulphuric
acid.
Lime.
a
trj
o
* <L>
£
Sulphate of lime.
The
44*5
Affinity.
C H E M
The affinities between the nitric acid and lime, and
between the fulphuric acid and the potaffi, which taken
together amount to 311, are the quxefcent affinities.
The affinities of the ffilphuric acid and the lime, and
of the nitric acid and the potaffi, are the divellent af¬
finities which are oppofed to the firft. But the amount
of the latter is equal to 325, that is, the combined af¬
finities of the fubftances which tend to form a new
combination, and thus they overcome the force of
the refifiance of the quiefcent affinities, as 325 exceeds
311.
Another example will ferve to make this decom-
pofition by double or compound affinity ftill more fa¬
miliar.
Muriate of potaffi.
Muriatic
acid.
Muriate
of <{ 36
barytes.
Barytes.
32
+
T 4
rr<5
Potaffi
  r Carbonate
^ 45 0f p0ta(]u
Carbonic
acid.
11S
This force
/ not con-
ftant.
Carbonate of barytes.
In this cafe a fqjution of muriate of barytes is mix¬
ed with a folution of the carbonate of potafh. The af¬
finity of the muriatic acid for the barytes, and that of
the potaffi for the carbonic acid, are the quiefcent affini¬
ties which are oppofed to any decompofing force. But
on the contrary, the affinity of the muriatic acid for
the potaffi, and that of the barytes for the carbonic acid,
are the divellent affinities. The quiefcent affinities are
only equal to 45, wffiile the fum of the divellent affini¬
ties is equal to 46 *, the latter mull therefore prevail.
The former combinations are broken, and inftead of
muriate of barytes, and carbonate of potafh, we obtain
muriate of potaffi and carbonate of barytes, which lat¬
ter is infoluble, and is therefore precipitated.
But Berthollet has drown that the force of affinity
is not conlfant and uniform, but is greatly iniluenced
by the quantity and the date of faturation. As, for in¬
dance, when two bafes aft in oppofition on an acid,
the acid divides its aftion in proportion to their re-
fpeftive mafl'es. If there be two acids indead of one,
and no feparation take place, either by precipitation
or crydallization, both acids will aft equally on both
bafes, in proportion to their mafies. If each of the
acids be previoudy combined with a bafe, and the fo-
lutions of their falls be mixed, the fum of the recipro¬
cal forces will be the fame as before. No muriate of
potadi or fulphate of lime will be formed j but there
will be a combination of potaflr, of lime, of fulphuric
and muriatic acid, which will have the fame degree of
faturation as before the mixture. And hence it hap¬
pens, that when two falls are mixed together, the mu¬
tual decompofition of which would produce combina¬
tions of very different proportions, the feparation of the
component parts, which diould refult from fuch de¬
compofition, is not perceptible. No change of bafes
therefore takes place.
The force of cohefion caufes the feparation which
takes place by precipitation or crydallization. A
1 s T R Y.
fimilar effeft is produced by the fame caufe, in the Affinity,
aftion of complex affinities. If a folution of fulphate l——v —'
of potafir be mixed with muriate of lime, diffolved
in a fmail quantity of water, the lime brought into
contaft wuth the fulphuric acid, will be more power¬
fully influenced by the force of cohefion, than tire pot-
alh. This is therefore to be confidered as an addition¬
al force to thofe which pre-exifted, and determines the
combination of the fulphuric acid with the lime, and
the precipitation of the new compound.
In all decompofitions effefted by compound affinity,
the prevailing affinity has been afcribed to thofe fub-
ftances which have the property of precipitating, or of
forming a fait which can be feparated by cryffalliza-
tion. Thus the knowledge of the folubility of falts
which may be formed in a liquid, will point out thofe
fubffances which are leaff foluble, and therefore molt
apt to precipitate. To thefe fubftances chemifts for¬
merly afcribed the ftrongeft affinity. Il9
Lime, magnefia, flrontites, and barytes, form infolu-Moft info-
ble lalts with carbonic acid. When therefore, any ofhiblecom-
the foluble falts of thefe earths are mixed w ith alka- Pouncb Ple_
line carbonates, an exchange is produced, from whichC pitate‘
reiult the formation and precipitation of an earthy car¬
bonate. The compound of fulphuric acid and barytes
forms an infoluble fait. When, therefore, a folution
of a fulphate is mixed with that of a fait of barytes, a
precipitation of fulphate of barytes, which is infoluble,
will be effefted. The fulphate of lime has alfo but
little folubility, and confequently it is much difpofed to
precipitate. Lime therefore decompofes all the fo¬
luble fulphates. But the fulphate of lime being much
more foluble than the fulphate of barytes, the lalts of
barytes, which are more foluble than the fulphate of
lime, decompofe it.
There are other circumftances which tend to change
the aftion of compound affinities. This aftion is great¬
ly influenced by the greater or lefs folubility of falts. I20
But the folubility of falts is varied by temperature. In Tempera-
eftimating the refult of compound affinities, therefore,ture t0 be
the degree of temperature muff be confidered and ta_ conilclered.
ken into the account. To give an inftance of this effeft,
nitrate of potaflr mixed with muriate of foda, cryftal-
lizes at a low temperature. During the evaporation
the muriate of foda is feparated. No change of bafes
will take place, becaufe the nitrate of foda is fomewhat
more foluble when cold, than nitrate of potafli j and
muriate of potaffi is^more foluble when hot, than muri¬
ate of foda.
The aftion of complex affinities may alfo be changed
by the formation of a triple fait which precipitates ;
but if the folubility of the combination be known, the
decompofition which is effefted, and the refulting com¬
pounds, may alfo be forefeen.* * Bertlol-
According to the theory of Berthollet, all fubftan- let's Rt~
ces in the liquid ftate exert a reciprocal aftion. lnfearci,es>
a folution of fulphate of potafli and muriate of foda,art’ 1‘5’
thefe two falts are not diftinft, nor do they become fo, ^'2I
until fome extraneous caufe produces their feparation. .‘v,y 'r10Cai
Sulphuric and muriatic acids, potafh and foda, are"
contained in the liquid. To afcertain what combina¬
tions are produced by the force of cryftallization, he
made the following experiments.
• <5 r ^ 122
“ Experiment 1.—A mixture was made of equal parts Force of
of nitrate of lime and fulphate of potafh : after the fe- cryftalliza-
parationtion*
CHEMISTRY, '467
Aftnity. patratlon of the fulphate of lime formed in the com-
mencement, and of which no further mention ftvall
be made in the following experiments, the liquid was
evaporated, and nitrate of potafh and fulphate of lime
were alone obtained by fucceflxve operations. Yet,
after the laft evaporation, fome cryfials of fulphate of
potalli were obtained : there was but a fmall rehdue of
uncryftallizable liquid, in which carbonate of foda and
nitrate of barytes produced precipitations } whence it
appears that it confided of a fmall quantity of fulphu-
ric acid and lime, and very probably of a larger portion
of nitrate of potafii.
“ The quantity of fulphate of lime which precipitated
during this evaporation, was much greater than what
could be diffblved in an equal quantity of water j
whence it appears that its folubility was augmented by
the attion of the other fubftances.
“ Experiment 2.—Two parts of fulphate of potafii, and
one of nitrate of lime, yielded, by the firlt evaporation,
fulphate of potafii and fulphate of lime *, and by the
following, nitrate of potafii with the two fulphates, the
proportions of which continued to diminifh until the
falls ceafed to cryftallize : only a few drops of uncryfial-
lized liquid remained, in which no precipitate was for¬
med on adding to it fome carbonate of foda, but this
effeft was produced by the nitrate of barytes; whence
it appears probable that the liquid confifted of ful¬
phate of potafii, and a fmall proportion of nitrate of
potafli.
“ Experiment 3.—Two parts of nitrate of lime, and
one of fulphate of potafii, yielded by the firft evapo¬
ration a fmall quantity of fulphate of lime, and on
cooling,, fome nitrate of potafii j by the fucceeding
evaporations nothing but nitrate of potafii was obtain¬
ed. After the lafi, however, fome crvfials of lulphate
of lime were perceivable on the furface of the liquid.
Though the refidue, which was abundant, was re¬
peatedly put to evaporate and cool, no cryfiallization
was effeified. This uncryftallizable refidue, treated with
alcohol, yielded an abundant precipitate, in the folu-
tion of which in water no precipitate could be pro¬
duced by nitrate of barytes ; whence it appears that
it contained no fulphuric acid, and that it wras compof-
ed of pure nitrate of potafti. What had been dif-
folved in the alcohol was nitrate of lime, with a fmall
proportion of nitrate of potafii : the uncryftallizable
refidue confifted, therefore, of nitrate of potafii and
nitrate of lime.
“ It appears that the fulphate of lime was rendered
much lefs foluble in this than in the preceding ex¬
periments ; and that the aflion of nitrate of lime pre¬
vented a confiderable quantity of the nitrate of potafli
from cryftallizing.
“ Sulphate of lime was neceffarily formed in thefe
three experiments, becaufe its component parts were
in contacl ; and the infolubility of the compound for¬
med by them, occafioned its precipitation to a certain
extent.
“ In the firft and fecond experiments, the fulphate of
lime was rendered much more foluble than it natural¬
ly is, by the aftion of the fubftances in folution ; but
in the third experiment, its folubility was not perceptibly
increafed, for this resfon, probably, that the nitrate of
lime and nitrate of potafti, which exifted in the uncryl-
tallizable liquid, had mutually faturated each other fo
much as to diminifti their action on the fulphate of Affinity,
lime ^ ' }
From thefc confiderations, he deduces the theory of ^ '
uncryftallizable refidues : which the fucceeding obferva-fedrches,
tions tend to confirm. art. 13
“ Saline fubftances exert a mutual aftion, which aug¬
ments their folibility; as has been proved by the ex¬
periments publifhed by my learned colleague Yau-
quelin. This reciprocal a£lion varies in different falls;
it was once fuppofed that the folubility of the nitrate of
potafii was not augmented by the adliou of earthy falls ;
and yet it is augmented more by them than by any
others.
“ There muft be, doubtlefs, in this relpeft, fome dif¬
ference arifing from the nature of the falls, in the ef»
fe£! which they produce ; but this difference is, in ge¬
neral, very trifling, compared to that refulting from
the force of eryftallization.
“ Experiment 4.—A mixture of equal parts of nitrate
and fulphate of potafli, yielded by evaporation, and
fucceflively, according to their folubility, fulphate of
potafti and nitrate of potafti, without leaving any un¬
cryftallizable refidue ; but having made a fimilar ex¬
periment with a mixture of nitrate and fulphate of fo¬
da, each of which has but a feeble tendency to cryftal¬
lize, and nearly an equal degree of folubility, there w7as
feparated by cryftallization but a fmall portion of the
fulphate of foda, the other parts of the mixture con¬
tinuing in the liquid ftate, incapable of being cryftal-
lized by anv means. Muriate of foda and fulphate of
alumine, fubmitted to the fame treatment, were perceiv¬
ed to become more foluble ; but they were totally fe¬
parated in the end by alternate evaporation and cool-
ing.
“ It appears, then, that fubftances which are endued
with an a&ive tendency to cryftallize, though rendered
more foluble than they naturally are, feparate however
in the order of their infolubility, without leaving any,
or but very little, uncryftallizable refiduc.
“ But when a mixture confifts of falls which have but
a weak tendency to cryftallize, their mutual action
counterafts that tendency, fo that a large portion of
uncryftallizable liquid remains : this eftefi is ftill more
complete when the mixture contains a fubftance natural¬
ly unctyftallizable, as in the third experiment, in which
there was an excels of nitrate of lime, the a£tion of
which excefs on the nitrate of potafh rendered a great
portion of it uncryftallizable.,,f \ RH.
From this it appears, Berthollet obferves, that the
formation of falls obtained by cryftallization, depends
on the proportions of the fubftances which aft on each
other ; and combinations may be formed which vary
from the proportions of the fubftances employed, or
the ftage of the operation ; that is, from the propor¬
tions which continue in aftion, when the combinations
which might take place are not endued with a force
of cohefion fufficient to withdraw them from the fphere
of aftion.
Ninth Law.
• I23
Affinity is in the inverfe ratio offaturation. Affinity-
In moft of the combinations which take place be-diminiilies-
tween bodies, there exifts a certain determinate pro-^w^nlss the
portion of the quantity of the fubftances which iormj^’h®^ a
the compound. On this indeed depend the conftancy
and
448
Affinity.
124
Saturation.
C H
and permanency, both of natural and artificial com¬
pounds. It is to this uniformity and permanency that
their charafteriftic properties are owing ; for when the
proportions in compound bodies vary, although the con-
llituent parts be of the fame nature, yet the properties
of the compound are greatly changed. 1 hus, in a
cafe already mentioned, the different proportions of
oxygen with lead, different compounds are produced j
■with a fmaller proportion of oxygen, the refulting com¬
pound is yellow, but with a greater it is red.
As there are certain limits to the proportions in
which bodies combine together, beyond which they
cannot pafs, thefe are called the points of faturation ;
and when two bodies, in uniting together, have reach¬
ed this point, they are faid to be faturated, or the one
body is faid to be faturated with the other : in other
words, the change has taken place, and a new com¬
pound is formed. When, for inftance, a fait is diffolv-
ed in water, as common fait, the water combines on¬
ly with a certain proportion $ and whatever quantity of
fait is added beyond this proportion, it falls to the bot¬
tom undiffolved. The reafon of this is, that the parti¬
cles of the fait are held together by their affinity for
each other j that is, by the force of cohefion. Now,
before any combination can be effe£fed between the
particles of the fait and the water, this force muft be
overcome. The force of affinity, therefore, between
the water and the particles of fait, is greater than that
between the particles of fait themfelves, and thus they
are feparated and diffolve in the water : but this force
of affinity between the water and the fait is limited j
v and when it has arrived at its utmoft limit, the a&ion
between the twm bodies ceafes. The two forces which
were oppofed to each other \ that is, the force of affi¬
nity between the water and the fait on the one hand,
and the force of cohefion between the particles of the
fait on the other, are balanced. The water in this
cafe is faid to be faturated with fait.
In a fenfe fomewhat fimilar, the word neutralisa¬
tion has been employed. When to an acid there is
added the folution of an alkali to a certain point, they
combine together, and form a compound, in which
the properties of the acid and of the alkali totally dif-
appear. They are then faid to have neutralized each
other j and hence the name of neutral falls, which has
been given to thefe compounds.
in different Some bodies, it would appear, enter into combina-
proportions. tion with others, only in one determinate proportion,
and fome in two proportions, and thefe proportions are
denominated their maximum and minimum of fatura¬
tion •, that is, the fmalleft and greateff proportions in
which they combine with each other. There is ano¬
ther fet of bodies which combine in any proportion
between the higheft and the lowed: point, while a
fourth fet combine only in certain determinate propor¬
tions between thefe points.
Nowq from thefe obfervations, let us endeavour to
illuftrate the meaning of this law, by attending to
what takes place in the different combinations of bo¬
dies with each other. A fmaller quantity of fait dif-
folved in a given quantity of water, is held in combi¬
nation by a greater force of affinity, than a greater
quantity ; becaufe this force is to be efiimated by the
affinity which exifts between the fait and the water,
E M I s T R Y.
and its mafs. The nearer, therefore, it comes to the Affinity,
maximum or higheft point of faturation, the weaker is —v*~-
the affinity between the water and the fait j and in ap¬
proximating to this point, this force is gradually dimi-
nilhed, till at laft it entirely vaniflies.
When two bodies combine together in twro different
proportions, or what are called the maximum and mi¬
nimum points of faturation, the force of affinity is
greateft between the two bodies at the lowreft point.
Suppofe that two bodies, A and B, can enter into
combination with each other, in two different propor¬
tions. Suppofe the quantity of A is rr 20 grs. and the -
firft portion of B which combines with it is rz: 10 grs. ;
it is evident from this combination, that part of the
force of the affinity of A is exhaufted, but ftill it com¬
bines with another portion of B ; fuppofe this is —5 grs.
and then it has reached its higheft point of faturation,
or the maximum. But as the laft portion of B, which
combined with A, is retained in the compound by the
force of affinity in A, wdiich remained f after its com¬
bination with the firft portion of B, it is obvious that
this force muft be greatly diminiffied, and therefore
the laft portion of B will be molt eafily feparated from
its combination with A j and this accordingly is found
to hold in all cafes.
Tenth Law.
Between two compound bodies which are not atled on
by compound affinity, decompoftion may tale place, if the
affinity of two of the principles for a third be greater
than that which unites this third to one of the two frfl,
although, at the moment of aclion, the union between the
two frf does not exi/l. I2s
This is called difpofing or predifpofing affinity, be- Difpofing
caufe no change takes place without the influence or affinity,
aftion of a third body on fome of the compounds; for
it is this adlion which operates the formation of the
compound, and the decompofition of another com¬
pound, without the formation of the firft. To have a
clear conception of this difpofing affinity, let us fup¬
pofe that there are two compounds AB and CD •, the
affinity of whofe conftituent parts, that is, the affinity
between A and C, and the affinity between B and D,
is not greater than the affinity which exifts between
AB and CD. In this cafe, it is obvious that no de¬
compofition can be effefted by compound affinity, be¬
caufe the fum of the quiefcent affinities exceeds the
fum of the divellent \ but if the force which tends to
combine B and C together, added to that which tends
to unite the compound BC to D, be greater than the
force of cohefion between the compounds AB and CD,
the refult of this adlion will be a decompofition, the
formation of a new compound BCD, and the repara¬
tion of the firft component part A.
Water is compofed of two fubftances, wdiich have
received the names of oxygen and hydrogen. Sulphur
has no direft aftion on water. This ffiew’S that the af¬
finity between fulphur and any of the conftituent parts
of the water, is not fo great as the affinity of the oxy¬
gen and hydrogen for each other ; but if fulphur be
united with an alkali, the w^ater is decompofed by this
combination, although there is no affinity between the
alkali and the oxygen. The fulphur combines with
the oxygen of the wrater, and forms fulphuric acid. It
/
I
C H E M I S T R Y. 449
Light, is this attra&ion which favours the decompofition of
1 v ' the water, and is therefore called a predlfpofing ajji-
niiy.
Such then are the phenomena of chemical a£lion,
which have been obferved and clafled together. The
knowledge of the laws of affinity, and the knowledge
of chemiftry, may be regarded as fynonymous terms,
- becaufe it is by the obfervation of the laws by which
the changes that take place among bodies by chemical
affinity are produced, that this fcience can be improved
and extended. The detail of chemical fcience, therefore,
may be regarded as the hiftory of affinities. We there¬
fore proceed in the following chapters, to examine the
properties of thofe bodies, the knowledge of which be¬
longs to chemical fcience j the changes which take
place by the adlion of affinity, and the new compounds
which are the refult of thefe changes ; and, at the fame
time, to point out fome of their applications and
ufes.
Chap. II. Of LIGHT.
*
Light and heat, which are to be treated of in this
and the fucceeding chapters, are highly interefting,
not only as curious fubjedls of fpeculation, but as a<fi>
ing a very important part in the changes which are
conftantly going on among natural bodies. Indeed no
change happens, in which the one or the other, and
fometimes both, is not either abforbed or extricated.
Light, of which wTe are now to treat, is the principal
agent in many chemical procefles ; and this, as well as
the aftonilhing velocity of its motions, and the proper¬
ties which it has of penetrating and traverfing fubftan-
ces with which it comes in contaft, render it an object
worthy of great attention.
Light, if it could be defined, is too familiar to eve¬
ry one to require any definition. It is by the light of
the fun, or that which proceeds from burning bodies,
that we are informed of the prefence of objefts; or the
rays of light proceeding from thefe bodies, and enter¬
ing the eye, produce the fenfation of vifion. We have
I27 no certain knowledge concerning the nature of light.
Opinions Various conjectures, however, have been made, and
of the na- various theories have been propofed, with regard to it.
ture ot Two of thefe w'e ffiall only mention. According to
'S1 ' Des Cartes, Huygens, and fome other philofophers,
i2S all fpace is filled up with a very fubtile fluid, and this
Anundu- fhiid is agitated or put in motion by the fun, or burn-
Jating fluid, ing bodies. This motion confifts of vibrations or un¬
dulations, which, extending themfelves and reaching
the eye, render the bodies which have produced thefe
motions, vifible.
The other theory is that of Newton and his follow'-
I29 ers. According to this theory, light is fuppofed to be
Material, a real emanation from luminous bodies, that is, a fub¬
tile fluid, confifting of peculiar particles of matter
which are conftantly feparating from luminous bodies,
and by entering the eye, excite the fenfation of light,
or the perception of the objeCls from w-hich it proceeds,
or thofe from which it is reflefted. This theory, which
has been deduced from a great number of faCls and
obfervations, was eftabliffied by Newton by mathema¬
tical demonftration. If then it be admitted, that light
is a fubtile fluid, confifting of minute particles, feveral
confequences follow, which require explanation, with
Vol. V. Part II.
regard to the fize, the velocity, and the momentum of Light,
thefe particles. In what followrs, we (hall confider v
light writh regard to its phyfical properties, its chemi¬
cal properties, or the effe£ts it produces on bodies with
wffiich it enters into combination j and, laftly, the
fources from which it is obtained.
Sect. I. Of the Physical Properties of Light.
130
I. One of the moft aftonifhing properties of light is Velocity
its velocity. It has been obferved by aftronomers, that
the eclipfes of the fatellites of the planet Jupiter ap¬
pear to take place fooner, when that planet is neareft
to the earth, and later when Jupiter is on the oppofite j-ji
fide of his orbit from the earth. Roemer, a Danilhclifcovered.
aftronomer, in attempting to account for this apparent
anomaly, proved that it wras owing to the difference of
time which the particles of light required, to pafs
through the femidiameter of Jupiter’s orbit •, and from
this he demonftrated, that the particles of light move
through one half of the diameter of the earth’s orbit in
about eight minutes. This difcovery of Roemer has
been fully confirmed by the theory propofed by Dr conffimed.
Bradley, to account for the aberration of the light of
the fixed ftars. From thefe data it has been comput¬
ed, that light moves with the velocity of 2GO,oco
miles in a fecond ;—a velocity of which the human
mind can form no diftinft conception. But in com¬
paring this velocity with that of a cannon ball, it may
be obferved, that light paffes through a fpace in about
eight minutes, w hich a cannon ball with its ordinary
velocity could not traverfe in lefs than thirty-two
years! # . I33
2. From the remarkable velocity of light, may be Particles
inferred the extreme minutenefs of its particles. The very mi-
force with which moving bodies ftrike, is in proper-riUte‘
tion to their maffes, multiplied by their velocities. If,
therefore, the one or the other, or both, be incrcafed,
the ftriking force is proportionally augmented ; and
confequently, if the particles of light were not ex¬
tremely fmall, their exceffive velocity would be high¬
ly deftruftive. Indeed, were they equal in bulk to
the two millionth part of a grain of fand, this impulfe
would not be lefs than that of fand (hot from the
mouth of a cannon.
The minutenefs of the rays of light may be alfo de¬
monftrated from the great facility with which they pe¬
netrate and pafs through tranfparent folid bodies. In
moving through fuch bodies, light feems not to fufter
the fmalleft diminution of its velocity. If there
is nothing to obftnnSt the rays of light which proceed
from a candle, it will fill the whole fpace within two
miles around, almoft inftantaneoufly, before it has loft
any fenfible part of its fubftance.
3. When a ray of light falls on a polifhed fubftance
in a perpendicular direftion, it is thrown back in the
fame dire&ion *, but wffien a ray of light falls on the
fame body obliquely, it returns from the furface on the
oppofite fide of a perpendicular line drawn from the
point on which the ray falls, and at an equal diftance
from that perpendicular. The angle which the ray of
light forms with the perpendicular as it falls, is equal
to the angle which it forms with the fame line, when
it is thrown back. The firft angle is called the angle
of incidence, and the fecond the angle of refedhon.
3 L Hence
CHEMISTRY.
Inflection.
136
Refraction
o 1:57
Spectrum
Hence the optical law, that the angle of incidence is
equal to the angle of reflection. When the rays of
light fall obliquely on poliflred furfaces, they are re¬
flected before they touch thefe furfaces, which is fup-
pofed to be owing to a repulfion between the particles of
light and the particles of the polifhed body. But when
rays of light fall obliquely on a tranfparent fubitance, as
a plate of glafs, they pafs through to the other fide,
and then return to the fame furface, and are reflected.
4. When a ray of light is admitted into a dark
room, through a fmall hole, it forms a luminous fpot
on any objeCt oppofite to that from which the light
proceeds ; and if the blades of two knives are placed
on oppofite fides of the hole, having their planes pa¬
rallel to the plane of the window ftrutter or pafteboard
through which the ray pafles, when the edges of the
knives are brought near each other, the rays of light
are drawn from their former direction towards the
edges of the knives, and the luminous fpot appears en¬
larged. This is called the inflexion of light. A fi-
milar effeCt is produced by nearly {hutting the eyes,
and looking at a candle. The rays of light appear to
proceed from it in various directions 5 for the light, in
pafling through the eye-laflies, is infleCted, and is di¬
vided into feparate beams, diverging from the lumi¬
nous objeCt.
5. A ray of light pafling from one medium to ano¬
ther, moves on in the fame direction j as for inftance,
when light pafles from air to water, or from water in¬
to air j but if a ray of light pafles in an oblique direc¬
tion from one medium to another, it is bent from its
former courfe, and then moves on in a new direction :
this is called the refraSlion of light. A ftraight rod,
which is introduced obliquely into a veflel of water,
appears bent at the place where it touches the furface
of the w'ater. This is owdng to the refraCtion of the
rays of light pafling from the rarer medium of the air
to the denfer medium of the water.
When the light pafles into a medium of greater den-
fity, as for inftance from air into wrater, it is rcfraCted
or bent towards the perpendicular j but when it pafles
from a denfer into a rarer medium, as from water into
air, it is refraCted from the perpendicular. The mea-
fure of the quantity of this refraClion is eftimated by
the denfity of the medium ; with this exception, how¬
ever, that if the medium be a combuftible fubftance,
the refraftive power is then found to be greater. It
was from the obfervation of this law of the refraClion
of light, that the conjeCture which was thrown out by
Newton, of the combuftible nature of water and the
diamond, which has been verified by the difcoveries of
modern chemiftry, occurred to the mind of that faga-
cious philofopher.
6. When a ray of light is admitted through a fmall
hole, and received on a white furface, it forms a lu¬
minous fpot. If a denfe tranfparent body be interpo-
fed, the light will be refraCted, in proportion to the
denfity of the medium 5 but if a triangular glafs prifm
be interpofed, the light is not merely refraCled, but it
is divided into feven different rays. The ray of light
no longer forms a luminous fpot, but has aflumed an
oblong fhape, terminating in femicircular arches, and
exhibiting feven different colours. This image is cal¬
led the fpeClruro, and, from being produced by the
prifm, the prifmatic fpeBrum. Thefe different colour¬
ed rays appearing in different places of the fpeClrum,
Light.
fhew that their refraClive power is different. Thofe of fe^en COi>
which are neareft the middle are the leaft refraCled, iours.
and thofe which are the moll diftant, the greateft.
The order of the feven rays of the fpeCtrurn is the fol¬
lowing : RED, ORANGE, YELLOW, GREEN, BLUE, IN¬
DIGO, violet. The red, which is at one end of the
fpeClrum, is the leaft, and the violet, which is at the
other end, is the moll refraCled.
Sir Ifaac Newton found, if the whole fpeClrum
was divided into 360 parts, the number of the parts
occupied by each of the colours to be the following:
Red, 45 parts.
Orange, 27
Yellow, 48
Green, 60
Blue, 60
Indigo, 40
Violet, 80
Thefe different coloured rays are not fubjeCl to farther N0t farther
divifion. No change is effeCted upon any of them by divifible.
being farther refraCled or refleCled j and, as they dif¬
fer in refrangibility, fo alfo do they differ in the power
of infleClion and refleClion. The violet rays are found
to be the moft reflexible and inflexible, and the red
the leaft.
7. Light, it is well known, feems to fuffer no in¬
terruption in pafling through fome bodies j fuch are
glafs or water, but it is interrupted in its paflage
through other bodies, as a piece of wood or ftone.
The firft fet of bodies are called tranfpare7it, and the
other opaque. The denfity of water or of glafs is
greater than that of a piece of wood. It cannot there¬
fore be owing to the denfity of the latter, or the clofe-
nefs of the particles which compofe it, that the tranf-
miflion of light is prevented. In the explanation which
has been given by Newton, it is fuppofed that the Par* xranlpa-
ticles which compofe tranfparent bodies, are of equalrenCy.
denfity, and are uniformly arranged } but in opaque
bodies he fuppofes the particles are of unequal denfity,
or are not uniformly arranged. From the uniform ar¬
rangement and equal denfity which, according to this
explanation, are fuppofed to exift in tranfparent bodies,
the light pafling through them, moves in a ftraight
line, becaufe it is equally attraCled by the particles of
the body. But in the latter (the opaque bodies) the 14I
attraClion between light and the particles of the body paCl
is unequal •, its direction is conftantly changing, till at
laft it is entirely interrupted.
8. Dr Herfchel, who has made fome interefting dif-iiiuminat~
coveries concerning light and heat, found that the il-ing power,
luminating power of the different rays was different.
From the obfervations which he made on this fubjeCl,
he fays, that “ with refpeCt to the illuminating power
afligned to each colour, wTe may conclude, that the
red-making rays are very far from having it in any
eminent degree. The orange poffefs more of it than
the red, and the yellow rays illuminate objeCls ftill
more perfectly. The maximum of illumination lies in
the brighteft yellow, or paleft green. The green it-
felf is nearly equally bright with the yellow j but
from the full deep green the illuminating power de-
creafes
C H E M
Light.
* PM.
Tranf.
vol. XC.
p. 26.
creafes very fenfibly j that of the blue is nearly upon a
par with that of the red j the indigo has much lefs
than the blue ; and the violet is very deficient*.”
Sect. II. Of the Chemical Properties of Light.
x. From the properties of light which have now
been detailed, it appears that it is fubjeft to the uni-
verfal law of attradtion, as well as other bodies •, but
Light en- it is alfo found to enter into chemical combination
ters bodies, with many fubftances. Thefe fubftances, it has been
difcovered by experiment, after being for fome time
expofed to the light, and carried into a dark place,
appear luminous. It is found, however, that this pro¬
perty is loft when they are kept in the dark, and they
do not recover it till after they have been again ex¬
pofed to the light. Some fubftances poffefs this proper¬
ty in a greater degree than others. One, which was
difcovered by Mr Canton, who made a number of ex¬
periments on this phofphorefcent light, as it has been
called, is prepared by the following procefs. He took
fome oyfter-fhells and calcined them, after which they
were reduced to powder, and the pureft part of them
Canton’s was Put through a fine fieve. Three parts of this
pyrophorus. powder were mixed together with one part of the
flower of fulphur } the mixture was put into a cruci¬
ble, and firmly preffed to the bottom, which was then
expofed for an hour to a red heat. It was then re¬
moved from the fire, and when it cooled, the pureft
parts of the mixture were fcraped off, and put up in a
well-clofed phial. This is called Canton’s pyrophorus.
When this is expofed to the light for a fhort time, it
becomes fo luminous that objefts may be diftindlly
perceived in the dark, by the light which it emits. It
lofes this property, however, by being kept in the
dark, but recovers it again when it is expofed to the
light. And after being kept in the dark for fome
time, the light from the pyrophorus becomes feeble,
or is nearly extinft, but it may be revived or increafed
by plunging the phial into hot wrater. But if the
whole of the light has been feparated previous to the
application of heat, no farther application can caufe it
to emit light, till it has been expofed to a luminous
body. Thus it appears that light enters into com¬
bination with other bodies, and that it afterwards
leaves them without having undergone any perceptible
change.
2. If a quantity of purple-coloured fiuate of lime
(Derbyfhire fpar) be reduced to coarfe powder, and
expofed to heat in a dark place, it emits a great quan¬
tity of coloured light ; but when this light which has
been in combination with the fpar is once expelled, it
does not recover its property of ftiining in the dark,
as in the cafe of Canton’s pyrophorus.
Sunpofed to ^ ^as ^een fuPP0fed by fome, that the light emitted
be flow by thefe fubftances is the confequence of flow combuf-
combuftion.tion ; but many of the fubftances which have this pro¬
perty are not combuftible, and none of the changes
which take place during this procefs have been obferv-
ed. In fome cafes it would appear that the light which
is given out is different from that to which they were
*45
From
which it
is emitted
again.
I S T R Y. 451
expofed, and which they muft have abibrbed. In fame Light,
of the pyrophori, the blue rays were obferved to have i—-y—
a greater effefl, and the light which was emitted was
of a red colour. 147
3. Light, it is well known, is given out by a num-EtlllttjCl
ber of animal and vegetable matters, when the procefs
of putrefaftion commences. In this cafe it feems to&c.
conftitute one of their component parts. This parti¬
cularly happens to filh of different kinds, as the her¬
ring and the mackerel, and to this is fuppofed to be
owing the phofphorefcent light of the fea, which ap¬
pears when the water is broken and agitated. Thefe
phenomena were obferved by Mr Boyle and Dr Beale,
both in the flefti of quadrupeds and fifties, and earlier
by Fabricius ab Aquapendente and Bartholin in the
flefti of quadrupeds. Experiments were made on the
fame fubjetl by Mr Canton, whom we have already
mentioned, and more lately by Dr Hulme. From the
experiments of the latter he concludes, that this light A confti-
is a conftituent principle of marine fifties ; that it is in- tuent prin-
corporated with their whole (ubftance, making a partc^e‘
of it, in the fame manner as any other conrtituent
principle j that when this fpontaneous light is extin-
guiftied by fome fubftances, it may be again revived j
that the quantity of light emitted is not in proportion
to the degree of putrefaftion, but on the contrary the
greater the putrefcence, the lefs is the quantity of light
emitted.
For the fake of thofe who may wifti to repeat thefe
experiments, we (hall detail the following made on the
herring and the mackerel, in the words of the author.
The Flefh of Herring (g). I4^
(l.) “ A frefti herring was fplit, or divided longitudi- I^Hulme’s
nally by a knife, into two parts. Then, about four^^™"
drams of it, being cut acrofs, were put into a folu-
tion, compofed of two drams of Epfom fait or vitriolat-
ed magnefia, and two ounces of cold fpring water
drawn up by the pump. The liquid was contained
in a wide-mouthed three-ounce phial, which was placed
in the laboratory. Upon carefully examining the li¬
quid, on the fecond evening after the procefs was be¬
gun, I could plainly perceive a lucid ring (for the
phial was round) floating at the top of the liquid, the
part below it being dark *, but, on (baking the phial,
the whole at once became beautifully luminous, and
continued in that date. On the third evening, the light
had again rifen to the top *, but the lucid ring appeared
lefs vivid, and, on (baking the phial as before, the li¬
quid was not fo luminous as on the preceding night.
(2.) The fame experiment was repeated. On the fe¬
cond night, the liquid, being agitated, was very lumi¬
nous j on the third, not fo lucid $ and on the fourth
the light was extinguiflied.
(3.) With fea fait or muriated natron half a dram, and
two ounces of water. On the fecond night, the liquid,
when agitated, was dark j on the third, lucid j on the
fourth, very luminous ; on the fifth, it began to lofe
lighton the fixth, it continued to decreafe *, and on
the feventh it was quite gone. Neither the liquid, nor
the herring, had contracted any putrid fmell.
3 L 2 (4.) With
(a) The quantity ufed in each experiment was about four drams.
45 2
C H E M
(4.) With Tea water two ounces. On. the fecond
night, dark : on the third, fourth, and fifth, luminous ;
on the fixth, nearly extinft ; and on the feventh, total¬
ly. The piece of herring, when taken out and exa¬
mined, was remarkably fweet.
Roe of Herring (h).
(5.) With Epfom fait two drams, and water two
ounces. On the fecond night, the liquid was pretty
luminous } on the third and fourth, itill luminous}
and on the fifth its light was extintt.
(6.) With Glauber’s fait or vitriolated natron, two
drams to two ounces of water. On the fecond night,
when the phial was fhaken, as ufual in all thefe expe¬
riments, the liquid was pretty luminous j on the third,
lefs fo j and on the fourth the light was fcarcely vifi-
ble.
(?•) With fea water two ounces. On the fecond
night, dark j on the third, the liquid was moderately
luminous } on the fourth and fittn, it had extracted
much light j and on the feventh it was ftill fliining.
After this procefs, both the roe and the fea water re¬
mained perfectly iweet.
The Flejh of Mackerel.
(8.) With Epfom fait two drams, and water tvco
ounces. On the fecond night, the liquid was finely
illuminated j on the third, a fimilar appearance j on
the fourth, a diminution of light j on the fifth, it con¬
tinued lucid in a fmall degree j and on the fixth the
light was extinguifhed. ,
Roe of Mackerel.
(9.) With Epfom fait two drams, and water two
ounces. On the fecond night, the liquid, when agi¬
tated, was exceedingly bright , on the third, the fame j
| P/jil. and on the fourth and fifth, ftill lucid f.
Tranf. Dr Hulme found that fome fubftances have the
l8o°- power of extinguilhing this light. It was quickly ex-
P‘ l68‘ tinguifhed when mixed with water alone, with water
impregnated with lime, carbonic acid gas, or fulphu-
$ated hydrogen gas •, by fermented liquors and.ardent
fpirits •, by the acids, both concentrated and diluted ;
by the alkalies when difiolved in water j by many of
the neutral falts, as the folutions of common fait, Ep¬
fom fait, and fal ammoniac. It was alfo extinguifhed
by infufions of chamomile flowers, of long pepper and ox
camphor made with boiling hot water, but not ufed
till quite cool.
When the fubftances emitting this light were placed
in a freezing medium, the light was in a fhoit time
quite extinguifhed 5 but when expofed to a moderate
degree of temperature, it was revived. A moderate
degree of heat increafed this light, but it rvas extin¬
guifhed by a high temperature, and no luminous ap¬
pearance could again be difcovered.
! so 4. When all the rays of light are reikaed from any
Colour. body, that body is faid to be white ; but when all the
rays are abforbed, the body which abforbs them is
I S T R Y.
faid to be black : but experience informs us, that differ- bight. |
ent bodies abforb and refleft different rays. Thus, if
a body abforb all the rays excepting the yellow, that
body is faid to be of a yellow colour 5 or if a body
reflect the red rays, while the others are abforbed, it
is faid to be red. Thus the colour of the body is cha-
raftenzed by the colour of the ray which is refledted
or, which is the fame thing, this is the caufe of colour¬
ing bodies. # # It;r
5. One of the moft lingular effedts which is obferved EfFe<ftsot'
in the combination of light with bodies, is its power of light on
reducing the oxides of the metals. Some of thefe, as
for inftance, the red oxide of lead, when expofed to^a|ts>
the light of the fun, lofe fome of their weight. The
oxide^of gold may alfo be reduced in the fame way,
and the white falts of filver become black, and the
oxide is reduced } and xvhen that procefs is going on,
oxygen gas is emitted, which, it would appear, has
been feparated by the adtion of light. Some of the
rays are found to have a greater effedt than others.
Scheele, who made a fet of experiments to afcertain
the difference of effedt of the different-coloured rays
in blackening the muriate of filver, difcovered that
the violet ray was the moft powerful in reducing the
oxide of filver. _ _ 152
It w7as formerly the general opinion, that the colo-Peculiar
rific rays of light were the caufe of the redudtion of™)5-
the oxides of the metals, but the experiments and ob-
fervations of Meffrs Bockman and Ritter in Germany,
and of Dr Wollafton in England, prove that the mu¬
riate of filver is more ftrongly and rapidly darkened
by rays of the fun which have been more refradled
than the violet rays •, for it appeared that the muriate
was affedted in a fpace lying beyond the violet
light. Thefe rays, therefore, have not the property
of giving light, nor do they produce any fenfible de¬
gree of heat ; and thus it appears that there are three
different fets of rays } namely, rays which illuminate,
rays which warm without giving any light (1), and
rays which produce a chemical adlion on bodies, but
which give neither light nor heat. From the con-
fideration of thefe curious and interefting experiments,
it has been very naturally fuppofed, that the chemi¬
cal adlions dependent on folar light are owing to the
invifible rays which were refradted beyond the violet
rays 5 and that the colorific rays have no fhare in
thefe adlions : for it has been obferved, that the effedl
of the different colours increafes with their refrangi-
bility ; and that the whole is owing to the invifible
rays, which increafe in number or quantity as they ap¬
proach to the violet ray, and are in greateft quantity
at a certain diftance beyond it. ^
6. The abforption of light by plants produces ano- Light ab-
ther remarkable effedl. It has been long known, that fjrbed by
the green colour of the leaves of plants is produced by plants,
the light of the fun. Experiments were fir ft made to
afcertain this fa& by M. Dufay and fome others of
the French academicians. The fubjedl has been
farther profecuted and extended by Senebier of Gene¬
va. When feeds are Town in a dark place, they ve¬
getate.
(h) The quantity ufed in each experiment was about four drams,
(x) Thefe will be particularly mentioned in the next chapter.
C H E M I S T R Y. 453
"Light, getate, and the plant grows with confiderable luxuri-
*     ance 5 but it never has any green colour as long as
the lioht is excluded, the leaves continue white •, and
this happens although air be freely admitted. When
the plant in this ftate is expofed to the light, the green
colour begins to appear, and the plant aflumes its ordi¬
nary habit. It may be added, that while the plant re¬
mains wThite, it contains but a fmall quantity of com-
buftible matter, and it has but little tafte. When it
affumes the green colour after its expofure to the light,
it acquires its natural tafte, and the ordinary quantity
of combuftible matter. It is upon this principle that
the art of blanching celery and other garden plants
depends 5 by heaping up the earth about the items the
light is excluded, and thus they are deprived of any
pungent tafte, and become white and tender (k).
Sect. III. Of the Sources of Light.
The fun. 1. The principal fource of light is the fun. It has
been a queftion of more curiofity than utility, what is
the caufe of the fun conftantly emitting light, and what
are the means of repairing that wraite ? By calculations
it is fuppofed, that there ought to iffue from one fquare
foot of the fun’s furface in one fecond, Part
of a grain of matter, to fupply the confumption of
light; that is, at the rate of little more than two
grains a-day, or about 4,752,000 grains, or 6701b. in
6000 years, w’hich wrould have Ihortened the fun’s dia¬
meter about 10 feet, if it wras formed of matter of the
* Priejiky s denlity of water only. *
Optics, gut: at the time this calculation was made, the dif-
p' ^ coveries of Herfchel, of the conftitution of the fun,
were not known. The body of the fun, according to
the obfervations of this philofopher, is not luminous,
but opaque; and the light W’hich W’as fuppofed to come
from his furface, proceeds from a luminous atmoiphere Light,
which furrounds that body ; and there are probably ' ”v
fome means by which the wade that is conftantly go¬
ing on, is repaired. The light which comes from the
ftars is of the fame nature with that of the fun. 155
2. Another fource of light is burning bodies. In Combuftiorr
all cafes of burning, light is emitted. This light,
therefore, muft have been in combination with fome of
the fubftances which are employed in thefe proceffes.
3. But when bodies, without undergoing the procefs ^*5^
of combuftion, are heated to a certain temperature,
they emit light; and it would appear, from experiments
which have been made upon the fubjed, that all bodies
which are not decompofed before they arrive at the
proper temperature, begin to give out light, exactly at
the fame degree of heat. Iron heated to 635°> ac"
cording to Sir Ifaac Newton’s experiments, becomes
vilible in the dark ; at 7520 it fliines brightly; and be¬
comes luminous in the twilight at 884®. The tempe¬
rature is above iooo° when it ftiines in broad day
light. A red heat, according to the experiments of
others, commences at the temperature of 8oo°, and
when a body reaches the proper degree of heat, it ap*
pears luminous, independent of the air. Mr T. Wedg¬
wood, who made a number of experiments on this fub-
je£t, found that a piece of iron wore became red hot
when immerfed in melted glafs. Air, therefore, is not
neceflary to the (hining of ignited bodies.
It was alfo afcertained by Mr Wedgwood, that a
piece of red-hot metal continues to (hine for fome time af¬
ter it has been removed from the fire, wdrich proves that
conftant acceflions of light or heat are not neceffary for
the Ihining of ignited bodies. But if the red-hot
metal be ftrongly blown upon, it inftantly ceafes to
{hine, and thus, it appears, when the temperature is di-
miniftied, it ceafes to give out light f. \rPkil'
From Tranf. __
vol. Ixxxn-
p. 279.
(k) This is remarkably illuftrated by the following obfervations of Profeffor Robifon. ‘‘ Having occafion
in autumn ^74, to go down and infpea a drain in a coalwork, where an embankment had been made to keep
off a lateral run of water, and, crawling along, I laid my hand on a very uxunant plant, having a copious,
deep-indented, white foliage, quite unknown to me. I inquired of the colliers what it was. None of them
could tell me. It being curious, I made a fod be carried up to the daylight to learn from the workmen what
fort of a plant it was. But nobody had ever feen any like it. A few days after, looking at the fod, as it lay at
the mouth of the pit, I obferved that the plant had languilhed and died, for want of water as I imagined. But
looking at it more attentively, I obferved that a new vegetation was beginning with little iproutmgs from the
fame ftem, and that this new growth was of a green colour This rnftantly brought to my recelkaion the
curious obfervations of M. Dufay ; and I caufed the fod to be fet in the ground and carefully wa ered I was
the more incited to this, becaufe I thought that my fingers had contrafted a fenfible aromatic fmell by handling
the plant at this time. After about a week, this root fet out feveral ftems and leaves of common tanfy. The
workmen now recolle£ted that the fods had been taken from an old cottage garden hard by, where a great deal
of tanfy was ftill growing among the grafs. I now fent down for more of the fame fluff and feveral fods were
brought up, having the fame luxuriant white foliage. This, when brmfed between the fingers gave no aroma¬
tic fmell whatever. All thefe plants withered and died down, though carefully watered, and, m each theie
fprouted from the fame flocks frefli ftems, and a copious foliage and produced, among others, common tanfy,
fully impregnated with the ordinary juices of that plant, and of a full green colour. I have rePeated the
fame experiment with great care on lovage (leuficum vulgare), mint, and caraways. As thefe plants throve
veTv wen below in the dark, but with a blanched foliage, which did not fpread upwards, but lay flat on the
ground-in all of them there was no refemblance of fhape to the ordinary foliage of the plant; alloftheI"
died down when brought into daylight; and the flocks then produced the proper plants m Jien: ufual drefs, and
^FromLhlxotriSs^UhlugUrayfelf entitled to fay that the fun’s rays not only produced the green fecuU
of la™ butXite diftinguilhfng juices, and particularly the effential oils. The rurprovenrems winch have
been made in chemical fcicnce fince that time, have, I think, fully confirmed my conjeaure. Black U. * • 535
4^4 C H E M
Light. From the experiments of Mr Wedgwood, it appears
v that the gafes do not become luminous, even at a high-
Gafes^not er temperature. He took an earthen-ware pipe of a
luminous, zig-zag form, and placed it in a crucible filled up with
fand. The ends of the pipe were left uncovered.
To one end was attached a pair of bellows, and to
the other a globular veflel with a lateral bent pipe, to
let out air, but exclude the external light, and hav¬
ing a neck in which was inferted a circular plate of
glafs. The crucible, with the fand and the part of
the pipe contained in it, rvas heated to rednefs. The
eye was fixed in the neck of the veffel, which was then
obferved to be perfectly dark within. A ftream of
air was then direfted through the tube from the bel¬
lows, but this air which paffed through the red-hot
tube, was not luminous. A fmall ftrip of gold was
then fixed into the orifice of the tube oppofite to the
eye, and after two or three blafts, it became faintly
red ; which (hows that though the air was not lumi¬
nous, it was equal in temperature to what is called red
heat. Dr Darwin made an experiment of the fame
kind, and with a fimilar refult. The heated air was
altogether invifible; but when a bit of gold was intro¬
duced, it acquired a bright glow in a few feconds *.
4. Light is alfo emitted by attrition and percuflion.
In the experiments which were made by Mr Wedg¬
wood, on the attrition of bodies, he found that diffe¬
rent coloured rays were emitted ; fometimes it was a
and percuf-pure white light, as from the diamond ; fometimes of
a faint red, as from blackilh gun flint; and fometimes
of a deep red, as from unglazed white bifcuit earthen
ware. But this effefl produced by attrition, may per¬
haps be confidered as the fame with that of percuffion.
It is a familiar circumflance, that fparks of light are
emitted, when two hard bodies, as for inftance, twro
quartz ftones, are fmartly ftruck againft each other ;
and it appears that light is emitted, or fparks given out,
when thefe bodies are treated by percuffion or attrition,
even under water j and they feem equally luminous in at-
mofpheric air, oxygen gas, carbonic acid, or hydrogen
gafes. The emifiion of this light is accompanied with
a peculiar fmell, which varies in different bodies. The
fmell appears to be ftrongeft where the friftion is great-
eft } it has no dependence on the light produced by
attrition, becaufe it is often very ftrong when no light is
emitted. Rock cryftal, quartz, and other hard bodies,
f Hid. alfo emit this fmell under water f.
p. 42. When flint and fteel are ftruck fmartly together, a
fpark is produced which will communicate fire to com-
buftible fubftances. This fpark has been found to be
a particle of the iron which is driven off, and which
catches fire as it paffes through the air. It is to be
confidered as a cafe of combuftion, and quite different
from what happens when two ftones are rubbed or
ftruck againft each other.
The matter driven off, when ftones of quartz are
ftruck againft each other, confifts of fmall, black, fri¬
able bodies, which leave a black ftain when rubbed on
paper, and when examined with a magnifying glafs,
have the appearance of being fufed. The light is
produced in thefe cafes, by the fubftances ftruck to¬
gether having been red hot. Some have fuppof-
ed that they are a combination with oxygen j while
others, who have probably examined them more ac¬
curately, affert that they are pieces of the quartz fur-
■* Phil.
‘Tranf.
vol. Ixxxii.
p. 271.
158
Attrition
I S T R Y.
rounded with a quantity of black powder j and having
been raifed to a very high temperature, fet fire, in
their paffage through the air, to the combuftible bo¬
dies that are floating in it.
Caloric.
Chap. III. Of CALORIC.
The word in common language has ttvo dif-piai^l
ferent meanings. When we fay that wre feel heat, it1
muft mean the fenfation of heat excited in the body j
but when w-e fay that the fire or a ftene is hot, it
means that the power of exciting the fenfation of heat
in us, exifts in the ftone or fire. The one is the caufe,
and the other is to be confidered as the effe61. The
heat of the ftone or fire is therefore the caufe of the
fenfation of heat in the body. Thus the word foal is
generally employed to exprefs both the fenfation, and
the caufe of that fenfation. To prevent any ambiguity
in the ufe of thefe terms, the word caloric has been
adopted in the new chemical nomenclature, to fignify
that ftate or condition of matter by which it excites
in us the fenfation of heat 5 and in this fenfe it is now
to be employed.
The nature and effefts of caloric or heat are highly
interelling, as curious fubjefts of fpeculation j but the
knowledge of them is of the utmoft importance in the
ftudyof chemical phenomena, becaufe no change takes
place, no decompofition is effefled, and no new com¬
pound is formed, without the agency of caloric.
Sect. I. Of the Nature and Properties of Cjlqric.
Two opinions have been maintained by pbilofophersTwo opi-
concerning the nature of caloric. According to one,ni0ns*
it is fuppofed to be a peculiar fubtile fluid, of a high¬
ly elaftic and penetrating nature, which is univerfally
diffufed. According to the other opinion, it depends
on a peculiar tremor or vibration which exifts among
the particles of heated bodies.
Among the firft who feem to have adopted the lat-
ter opinion, was the celebrated Bacon. In his treatife,
De forma calidi, which he propofed as a model of
fcientific inveftigation, he enumerates all the fa£ts
which were then known concerning heat 5 and after a ^ ^eat
cautious confideration of thefe fa&s, he concludes, that f: ^otioni
heat is motion. The fafts on which he founded this
opinion, wrere derived from fome of the moft familiar
methods by which heat is produced in bodies. A
blackfmith can make a rod of iron red hot by ftriking
it fmartly with a hammer j the heavy parts of ma¬
chinery, by fri&ion upon each other, and the axles of
the wheels of carriages when heavily loaded, fome¬
times take lire. A fire may be kindled by the friflion
of two pieces of dry wood, and the branches of trees
ftrongly rubbed againft each other by the violence of
a ftorm, have fet fire to thick forefts. From the ob-
fervation and confideration of thefe fafts, this eminent
philofopher was led to conclude, that heat is the ef-
fe<5t of mechanical impulfe. Since the time of Bacon,
this theory has had many followers, and even at the
prefent day it is maintained by fome philofophers. 163
But the theory which fuppofes caloric or heat to beI)iftM!<fi:
a diftindt material fubftance, is now more generally ^ubfl;ances,
adopted. It was firft fuppofed by thofe who favou¬
red this theory, that this peculiar matter was chief¬
ly chara&erized by the great elafticity, or repulfive
1 power
Caloric.
164
Is attrailed.
165
Velocity.
166
Minute
particles.
167
Experi¬
ments to
afcertain
the weight
of caloric,
C H E M
power, of die particles among each other; but befides
this property, Dr Cleghorn fuppofed that it pofTeffed
another, namely, that while its particles have a ftrong
repulfion for one another, they are attracted by other kinds
of matter, with different degrees of force. But what¬
ever opinion may be formed of the nature of caloric, after
we have inveftigated its properties and effefts, we fhall
probably find, that the phenomena which it exhibits will
be eafier underftood, and more fatisfa&orily accounted
for, on the fuppofition that it is a diftinft fubftance.
1. The rays of light and caloric accompany each
other as they proceed from the fun, or from burning
bodies. It is therefore fuppofed that they move with
the fame degree of velocity 5 and if this be the cafe,
the velocity of the rays of caloric muff be equal to
200,000 miles in a fecond. An experiment made by
Mr Pi£tet proves the great velocity of the rays of ca¬
loric. Two concave mirrors, the one of tin, and the
other of gilt plafter, 18 inches in diameter, were pla¬
ced at the diftance of 69 feet from each other. “A
thermometer was placed in the focus of the latter, and
a heated bullet of iron in the former. When the
bullet was placed in the focus, a thick fcreen, which
was a few inches from the face of the metallic mirror,
was removed. The thermometer inftantly rofe, fo that
the time which caloric requires to move through the
fpace of 69 feet, cannot be ellimated. And indeed,
if caloric, as is moft probable, moves with the veloci¬
ty of light, the time that it paffes the diftance of 69
feet, or even 69,000 feet, is by far too minute to be
meafured by our inftruments 5 fo that no conclufion
whatever with regard to the meafurement of its velo¬
city, can be drawn from this experiment.
2. From the extreme velocity of caloric, and from
its being equal to that of light, it is concluded that its
particles are equally minute. From the accumulation
of caloric in bodies, and particularly from one ftriking
effedl which this accumulation produces, namely, ex-
panfion, it was natural to fuppofe that bodies having
received this addition, acquired an increafe of w’eight.
Experiments have therefore been made to afcertain
this effeft. Boerhaave weighed a mafs of iron of jib.
weight, while it was red hot, and afterwards repeated
the fame experiment with other metals, but found no
variation, either in the hot or cold bodies, but what
he could account for from the errors of the balance.
Mufchenbroeck fuppofed that heat is ponderous, or pro¬
duced by a ponderous fubftance 5 and Buffon thought
he had proved, by his own experiments, that a body
is heavier when it is hot than when it is cold j but
when fimilar experiments were repeated, particularly
by Dr Roebuck and Mr Whitehurft, with very nice
and delicate balances, the bodies which were weighed
appeared heavier cold, than when they were hot. This
feems to be owing to the rarefaction of the air fur¬
rounding that fcale in which the heated body is pla¬
ced *, the preffure of which is therefore lefs than that
of the air over the other fcale. From more recent ex¬
periments, and particularly one made by Dr Fordyce,
it appears that bodies become heavier, but in a very
fmall degree only, not by the increafe, but by the di¬
minution of temperature. When the whole quantity
of 1700 grs. of water was frozen, it was found to be,
when carefully weighed, -r^ths of a grain heavier than
it had been when fluid. At this time the thermome-
I S T R Y. ’ 455
ter applied to the veffel which contained the frozen Caloric. ^
w?ater, flood at io° j but when it was allowed to re- v
main till the thermometer rofe to 3 2°, it weighed only
•/^ths of a grain more than when fluid, and at the fame r<j8
temperature. But other experiments prove, that theunfuccefs-
addition of caloric to bodies produces no fenfible change™ *
on their weight. This feems to be placed beyond a
doubt by the accurate experiments of Lavoifier, which
were made with a view of afcertaining whether the
weight of bodies is altered by heating or cooling them j
but he found no difference.
In the year 1787, Count Rumford repeated the ex¬
periment of Dr Fordyce with the greateft care 5 and
varying it in every poffible wTay to avoid error, the re-
fults led him to conclude, that there is no fenfible. dif¬
ference in the wTeight of bodies, either by the addition
or abftra£tion of caloric. . _ # Repufliou.
3. Caloric agrees with light in another of its pecu¬
liar properties ; this is its repuljive power, or that ten¬
dency of its particles to feparate from each other. The
particles of caloric, therefore, can never be fuppofed
to cohere. .
4. As the rays of light are reflected by poliftied fur-Refle<ftl0n*
faces, fo it is found that the rays of caloric have, the
fame property. The Swedifti chemift Scheele difco-
vered, that the angle of refleflion of the rays of calo¬
ric is equal to the angle of incidence. This has been
more fully eftabliftied by Dr Herfchel. Some very in-
terefting experiments were made by Profeffor Pidtet of
Geneva, which proved the fame thing. Fhefe expe¬
riments were condudled in the following manner. Two
concave mirrors of tin, of nine inches focus, were pla¬
ced at the diftance of twelve feet two inches from each
other. In the focus of the one was placed the bulb
of a thermometer, and in that of the other a ball of
iron two inches in diameter, which was juft heated fo
as not to be vifible in the dark. In the fpace of fix
minutes the thermometer rofe 2 2°. A fimilar effeft
was produced by lubftituting a lighted candle in place
of the ball of iron. Suppofing that both the light and
heat a died in the laft experiment, he interpofed be¬
tween the two mirrors a plate of glafs, with the view
of feparating the rays of light from thofe of caloiic.
The rays of caloric were thus interrupted by the plate
of glafs, but the rays of light were not perceptibly di-.
minifhed. In nine minutes the thermometer funk I4°.j
and in feven minutes after the .glafs was removed, it
rofe about 12°. He therefore juftly concluded, that
the caloric refledled by the mirror, was the caufe Oa
the rife of the thermometer. He made another expe¬
riment, fubftituting boiling w'ater in a glafs veffel in
place of the iron ball 5 and when the apparatus was
adjufted, and a fcreen of filk which had been placed
between the two mirrors removed, the thermometer
rofe 30 ; namely, from 470 to 50°.
The experiments were varied by removing the tin
mirrors to the diftance of 90 inches from each other.
The glafs veffel, with boiling water, was placed in
one focus, and a fenfible thermometer in the other.
In the middle fpace between the mirrors, there was
fufpended a common glafs mirror, fo that either fide
could be turned towards the glafs veffel. \v7hen the
polilhed fide of this mirror w^as turned towards the
glafs veffel, the thermometer rofe only -j^ths of a de¬
gree ; but when the other fide, which was darkened,
0 x was
43 6
Caloric.
i7i
’Refraction.
172
Three fets
. of rays,
coloured
• and heat¬
ing.
H4
Invifible
have the
greateft
heating
power.
f Jour.
Hoy. Injl
vol. i.
p. 20(f.
CHEMISTRY.
was turned towards the glafs veflel, the thermometer
rofe 30.5. And in another experiment performed in
the fame way, the thermometer rofe 30 when the po-
lilhed fide of the mirror was turned to the glafs veffel,
and 90 when the other fide was turned. Thefe expe¬
riments fhew clearly, that the rays of caloric are re-
flefled from polifiied furfaces,|as well as the rays of light.
5. Tranfparent bodies have the powrnr of refrafting
the rays of caloric, as well as thofe of light. They
differ alfo in their refrangibility. So far as experiment
goes, the mofi: of the rays of caloric are lefs refrangi¬
ble than the red rays of light. The experiments of
Dr Herfchel fliew, that the rays of caloric, from hot
or burning bodies, as hot iron, hot water, fires and
candles, are refrangible, as well as the rays of caloric
which are emitted by the fun. Whether all tranfpa¬
rent bodies have the power of tranfmitting thete rays,
or what is the difference in the refraftive powxr of
thefe bodies, is not yet known.
6. The light which proceeds from the fun feems to
be compofed of three diftindt fubftances. Scheele dif-
covered, that a glafs mirror held before the fire, re-
flefled the rays of light, but not the rays of caloric j
but when a metallic mirror was placed in the fame fi-
tuation, both heat and light were reile&ed. The mir¬
ror of glafs became hot in a fhort time, but no change
of temperature took place on the metallic mirror. This
experiment ihewTs that the glafs mirror abforbed the
rays of caloric, and refledled thofe of light j while the
metallic mirror, fuffering no change of temperature,
relieved both. And if a plate of glafs be held before
a burning body, the rays of light are not fenfibly in¬
terrupted, but the rays of caloric are intercepted ; for
no fenfible heat is obferved on the oppofite fide of the
glafs 5 but when the glafs has reached a proper de¬
gree of temperature, the rays of caloric are tranfmit-
ted with the fame facility as thofe of light. And thus
the rays of light and caloric may be feparated.
Eut the curious experiments of Dr Herfchel have
clearly proved, that the invifible rays which are emit¬
ted by the fun, have the greateft heating powder. In
thefe experiments, the different coloured rays were
thrown on the bulb of a very delicate thermometer,
and their heating power was obferved. The heating
powTer of the violet, green, and red rays, were found
to be to each other as the following numbers:
Caloric.
Violet, 16.
Green, 22.4
Red, 55.
The heating power of the moft refrangible rays wras
leaft, and this powder increafes as the refrangibility di-
minithes. The red ray, therefore, has the greateft
heating power, and the violet, which is the moft re¬
frangible, the leaft. The illuminating powTer, it has
been already obferved, is greateft in the middle of the
fpeftrum, and it diminiflies towards both extremities •,
but the heating power, which is leaft at the violet
end, increafes from that to the red extremity : and
when the thermometer w7as placed beyond the limit of
the red ray, it rofe ftill higher than in the red ray, w;hich
has the greateft heating power in the fpedlrum. The
heating power of thefe invifible rays was greateft at
the diftance of 4- inch beyond the red ray, but it wTas
fenfible at the diftance of 14 inch.
Dr Herfchel’s experiments have been varied, and ftill
farther confirmed by a fet of experiments by Sir H.
Englefield, the refults of which were the following :
Therm, in the blue ray rofe
in the green
in the yellow
in the full red
in confines of the red
in 3' from 550 to 56°
in 3' from 540 to 58°
in 3' from 56° to 62°
in 2? from 56° to 72°
in 2-4' from 58° to 734°
quite out ofvifible light in 24' from 6l° to 790
The thermometer ufed in thefe experiments had its
bulb blackened with Indian ink.
In the following experiments, three thermometers
were employed 5 one had a naked ball, one was whiten¬
ed, and the other was blackened. They were expofed
to the fun’s rays till they became ftationary, when the
thermometer with the
Naked ball flood at 584*
Whitened ball 584°
Blackened ball 63°
In the full-red ray
In quite dark
In confines of the red
the blackened thermom. rofe in 2' from 58° to 6x°
w’hitened
blackened thermom.
whitened
black thermom.
white
in 3' from 550 to 58°
in 3' from 590 to 64°
in 3' from 58° to 584°
in 3' from 590 to 710
in 3' from 574° t° 6o4°
In other experiments which w-ere made afterwards, the refults were,
In the full-red ray
In quite dark 4 inch out of the red, the
black thermom. rofe
{
1
the black
white
thermom. rofe
in 3' from 66° to 82°
in 3' from 66° to 694°
in 3' from 70° to 84°
In this laft experiment, when the thermometer was
carried into the faint-red light, it funk quickly, and
rofe again as quickly, when carried into the dark fo-"
cus •, but when carried into the dark on the other fide
of the red light, it funk very rapidly, and did not ap¬
pear to receive any heat at all. f.
Thus it appears, that the rays of caloric and the
rays of light are different; for thefe experiments clear-
2
ly drew, that there are rays which produce heat, but
give no light, and rays which give light, but produce
no heat. It was formerly mentioned, that there is ano¬
ther fet of rays which give neither light nor heat, but
wTbofe exiftence has been fully demonftrated by the re¬
markable effeift which they produce in reducing the
metallic falts and oxides. The light which is emitted
from the fun then confifts of three diftintt fets of rays
which
C H E M
Caloric, which have been fully recognized by their different de-
ir-— grees Gf refrangibility and their different effe&s. The
heating rays are in the fmalleft degree refrangible j
the rays which have the greateft effed on the metallic
oxides are the moft refrangible, and the coloured rays
are in an intermediate degree. The invifible rays be¬
yond the red extremity of the fpe&rum, which are leaf!
refra&ed, have the greateft heating power j the invifi¬
ble rays beyond the violet end, which are moft re-
fraded, have the greateft power in reducing the metal¬
lic falts or oxides, and the rays in the middle of the
fpedrum have the greateft illuminating power.
Sect. II. Of the Effects of Caloric.
Effects of The effeds of fo powerful an agent as heat muft be
caloric dif- very confiderable, and thefe effeds are found to be dif-
dYffeTent ferent in different bodies, or as it is more or lefs accu-
fcodies” mulated in thefe bodies. One general effed is, that
the accumulation of heat enlarges, and its abftradion
proportionally diminilhes, the bulk of all bodies. When
this accumulation is continued in fome bodies, they
change their condition from the ftate of folid to that of
liquid $ and, when the accumulation is ftill greater, li¬
quid bodies are reduced to the form of vapour. Thefe
effeds, certainly curious and interefting of themfelves,
are of the utmoft importance in the phenomena of na¬
ture and in the proceffes of art 5 and the knowledge
of the laws which have been deduced from thefe re¬
markable changes, enables us to explain many na¬
tural appearances, and to improve many of the arts of
life,
1. Of Expamsion.
1. One of the moft general effeds of heat, it has
been obferved, is the expanfion of bodies ; that is,
when caloric is accumulated in any body, it is enlarged
in bulk ; and, when that quantity of caloric is abftrad-
ed, there is a correfponding contradion. Experience
teaches us, that this effed of caloric is invariable and
uniform in all the fimpler kinds of matter. In lome
bodies, however, there are feeming exceptions to this
general rule. In thefe bodies, when the temperature
rifes a little above, or falls a little below a certain
point, they are fubjed to irregular variations of their
bulk j but thefe irregularities are limited to a few bo¬
dies, and to certain ftates of temperature of thefe bodies:
for when they are expofed to equal variations of heat,
above or below the temperature at which thefe irregu¬
larities are obferved, the general law of expanfion uni¬
formly holds. The expanfion of all bodies by heat,
therefore, and their correfponding contradion by the
abftradion of caloric or by cold, may be confidered
as one of the moft general fads in chemical fcience.
2. There are many familiar inftances of the expan-
175
Caloric ex¬
pand- all
kodies.
177
Exceptions
I S T R Y.
fion of bodies by means of caloric, and this can be
proved by very fimple experiments. We (hall men¬
tion an example of this effed on bodies in the folid,
the liquid, and the gafeous ftate. ^
(1.) If a rod of metal, as of iron, of an inch in dia-jn a folid
meter, and fix or eight inches long, and the fame body,
thicknefs through its whole length, be exadly fit¬
ted to pafs through a hole in a plate of the fame metal,
and to be admitted lengthwife within the projeding
edges of a ruler while it is cold j the fame rod when
it is made red hot, will be found to have enlarged in
bulk fo much, that it will not fall between the projed¬
ing parts of the ruler, nor will it pafs through the
hole } but when it is cooled, or reduced to its former
temperature, it again contrads, and returns precifely
to its former dimenfions. _ 180
(2.) As an example of a liquid, whofe bulk is enlar-ja a liquid,
ged by the accumulation of caloric, fill the body of a
glafs veffel which has a long {lender neck with fpirit
of wfine. On the application of heat the liquid in the
body of the veffel is expanded, and rifes in the neck j
and when the heat is abftraded, and the liquid returns
to its former temperature, it is again contraded, and
returns to its former bulk. This experiment is moft
conveniently performed by immerfing the body of the
veffel in hot water. _ i$i
(3.) The expanfion of a body in the gafeous ftate by In an elaf-
the accumulation of caloric, is (hewn by the following tic fluid,
experiment. Let a quantity of air be confined in a
bladder, but not in fuch' quantity as that the bladder
{hall be fully diftended with it. If the bladder is ex¬
pofed to heat, the confined air expands, and the blad¬
der is fully diftended ; but when it is again cooled,
the air refumes its former bulk, and the bladder its
original flaccid ftate. I83
3. Thus it appears, that all bodies expand by heat, uniform in
and contraft by cold, and the quantity of this expan-the fame
fion is uniformly the fame in the fame bodies, whenbodies*
expofed to the fame temperature. But this quantity is
found to differ greatly in different kinds of matter, by
the fame increafe or diminution of their heat. In folid
bodies it is leaft, in liquids it is greater, but in elaftic
fluids greateft of all •, and in different kinds of folids,
liquids, and elaftic fluids, this difference is very confi¬
derable. The ratio at which this expanfion takes place
in different bodies, can only be afeertained by experi¬
ment j and, as the knowledge of this is a matter of
great confequence in many of the arts, experiments
have been made with this view by different philofo-
phers (l). . 1 r 'j • l83
The expanfion of gafeous bodies, we have laid, is very
greateft, that of liquids lefs, and that of folids leaft of different in
all, by being expofed to the fame degree of heat, which
178
Exparifion
proved.
will appear from the following proportions.
quids, and
elaftic
fluids.
f Atmofpheric air,! from 0 to 2I2o
100 cubic inches of < Water, ^ - '• *
LIron,
1
increafed to
1!
37.5 cubic inches,
°4-5
100.1
Von. V. Part II.
M
This
y See experiments on this fubjeft by Mr Elliot, Phil. Tranf. vol, xxaix. and by Mr Smeaton, ibid. vol.
xlviii.
458
Caloric.
» i in f
i§4
EfFedls of
expanfion
on brittle
fubftances.
CHEMISTRY.
1S5
In fitting
iron hoops
to carriage
wheels.
186
Different
metals un¬
equally af-
fedted.
187
Ufe of this
in conflruc-
ting the
pendulum.
4. This expanfive effeft of heat will enable us to
account for the cracking or breaking of veffels which
are made of brittle fubftances, by its hidden applica¬
tion or abftraftion. This is particularly the cafe with
thofe fubftances which have little flexibility, as caft
iron, glafs, or earthen ware ; and accidents of this
kind mofl: frequently happen in veflels made of thefe
materials. If, for inftance, heat be fuddenly applied
to a glafs veffel of confiderable thicknefs, its external
furface to which it is firft: applied expands more than
the internal parts ; the confequence muft therefore be,
that they are feparated or drawn afunder, and the vef¬
fel is fplit or broken.
5. One of the beft illuftrations of this expanfion by
heat and contra&ion by cold on folid bodies, is in the
application of iron hoops to carriage wheels. The
hoop which has been intended for the wheel is made
of rather fmaller dimenfions than exactly to fit it. It
is then made red hot, and while it is thus expanded,
it is applied to the wheel. It is fuddenly cooled by
throwing cold water upon it, when it contradts, and
returning to its former dimenfions, is ftrongly faftened
on the wheel.
The unequal contradlion at the fame degree of tem¬
perature, which is obferved among folids, liquids, and
aeriform fubftances, alfo takes place among folids them-
felves. Thus, different metallic fubftances, at the
fame temperature, are found to expand and contradl
very unequally.
6. Advantage has been taken of this unequal con-
tradlion of metallic fubftances, to remedy thofe defedls
and imperfections of delicate inftruments, which are
occafioned by the contra&ion and expanfion of the
fubftances employed in their conftruftion, when expo-
fed to different temperatures. Thefe inconveniences
were moft felt in inftruments wftiich were employed for
the meafurement of time, where great accuracy was
required. The fpring of a watch and the pendulum of
a clock being fubjeft to the fame law of contra&ion
and expanfion by heat and cold, in thefe changes, ne-
ceffarily caufed variations, in proportion to the extent
of the effe£h But as different metals were obferved
to expand unequally by the fame temperature, this was
applied to the conftru£lion of thofe parts of the inftru-
ment on which the accuracy of its indications depends.
The equable meafurement of time, for inftance, by a
clock, depends on the length of the pendulum always
continuing the fame. If it is fubjeft to variations
in length by expanfion or contraftion, there will alfo
be variations in the rate of its motions} for when the
pendulum is lengthened by heat, the clock goes flow¬
er ; and when it is fhortened by cold, it goes fafter.
It becomes therefore an object of great importance,
that thefe inftruments fhould go at an equable rate in
all temperatures •, but this can only be effsfted by ha¬
ving the pendulum fo conftru&ed, that it fhall neither
lengthen by heat, nor contraft by cold. This is
done by conftrudting a pendulum in the following
manner.
“ From the point of expanfion A (fig. x. Plate
CXLII.) a rod or thick wire, AB, of the lefs expan-
fible metal, muft; hang down a certain length. At the
lower end it muft have a ftud, or crofs piece, BC,
ftrongly faftened, and projedting a little to one fide.
On the projedling part, C, of this crofs piece, muft be
eredled a pillar, CD, of the more expanfive metal. Caloric.
To the top of this pillar, another crofs and projecting v—-v—'
piece, DE, muft be ftrongly faftened ; and, from this
laft, muft again hang dowm another rod or wire, EF,
of the firft metal, having the ball of the pendulum
at its extremity. And now, if the height of the pillar
CD be one-third of the length of the two rods taken
together, the pendulum can neither be lengthened by
heat nor fhortened by cold. For by the expanfion of
the pillar, the pendulum is fbortened, or the ball is
raifed nearer to the point of fufpenfion, becaufe the
upper end D of the pillar is more raifed by its expan¬
fion, than the lower end C is depreffed by the expan¬
fion of AB; and, on the other hand, by its contrac¬
tion, the pendulum is lengthened, or the ball is lower¬
ed j but, while this happens, the two rods, by their
expanfion or contraftion, produce a contrary effedl j
and the quantity of expanfion or contradlion is the
fame in the rods that it is in the pillar, the greater
length in the rods compenfating for the greater ex-
panfibility in the pillar. The confequence therefore
muft be, that the length of the pendulum, that is, the
diftance between the point of fufpenfion and the ball,
cannot be varied by heat or cold. Accordingly, the
clocks made for the ufe of aftronomers, have pendu¬
lums conftrufted upon this principle, in wftiich pillars
of the more expanfible metals are employed to counter-
a<ft the expanfion of the other parts of the pendulum-
. iSS
7. There are, however, fome remarkable inftancesThe bulkof
which are feeming exceptions to this general law ofwaterwhen
expanfion. This is the cafe with thofe bodies whichfrozen
pafs from the liquid to the folid ftate ; as for inftance,creaiec^
w’ater, wftien it affumes the folid form. Clofe veflels
which are filled with water, are burft when it freezes.
In an experiment made by Mr Boyle^ a brafs tube
three inches in diameter, which was clofed with a
moveable ftopper, was filled with water j when the
water was frozen, it raifed a weight equal to 74 lb.
with which the ftopper was loaded. In an experiment
by the Florentine academicians, a hollow brafs globe,
the diameter of whofe cavity was an inch, was burft
by freezing the water with which it wTas filled. Muf-
chenbroeck has computed the force neceffary to pro¬
duce this effeft, by eftimating it equal to a preflure of
27,720 lbs. weight. But the moft remarkable experi- rg9
ments to prove the expanfive force of ice, were made and a&s
by Major Williams in Canada, in the years 1784 andw.lt*1 Pro<ft*
1785. The iron plugs with which iron bombfhellsSIOUS force*
filled with water were clofed up by driving them in
ftrongly with a hammer, were thrown out to a great
diftance by the force of the congelation of the water j
and when the plugs were fo firmly fecured as to refift
this force, the ftiell itfelf was burft *. * Edln.
8. To the fame expanfive force in the congelation
of water, the burfting of water-pipes, the fplitting ofV0^n,Pa3*
trees and of rocks, is to be aferibed, wriiich not uri-
frequently happens when the water which has been teds,
colledled in their cavities or fiflures, is frozen. The
ftones of the pavement are alfo raifed and loofened by
the freezing of the water in the earth in which they
are imbedded, which is thus increafed in bulk, and
exerts its expanfive force.
9. Attempts have been made to difeover the caufe
of this aftonifhing effe&. According to fome, it is
owing
Caloric.
191
Accounted
for
19*
from the
new ar¬
rangement
of the par*
tides.
193
in caft iron.
194
The ther¬
mometer
invented.
195
Firft con-
drudion.
C H E M
owing to the extrication of the air which water holds
in combination in a denfe, nonelaftic ftate. When the
water is freezing, part of the air affumes the elaftic
form, and feparates from it $ but when the furface of
the water is covered with ice, no more air can make
its efcape. It is then confined, and forms thofe numer¬
ous cavities which are obferved in ice. In confe-
quence of thefe cavities, a mafs of ice muft be of great¬
er bulk than the water previous to congelation, and
cannot therefore be contained in the fame fpace: But
another caufe, which is perhaps the moll probable, has
been affigned for this increafe of bulk, and confequent
expanfive force. Liquids which on cooling become
folid, and affume a regular form, are always found to
increafe in bulk. Water, when it paflfes from the li¬
quid to the folid ftate, has a ftrong tendency among
its parts to arrange themfelves in a determinate man¬
ner. They affume the form of prifmatic cryftals,
which crofs each other at angles of 6o° and 120°. In
this way the increafe of bulk, and the expanfive force
of water when it is confolidated, are accounted for.
10. Some metallic fubftances, particularly caft-iron,
are obferved to enlarge in bulk, when they pafs from
the fluid to the folid ftate, in the fame way as water.
To this increafe of bulk in caft-iron when it cools, are
owing the fharpnefs and diftin&nefs of the lines in
the ornamental figures on grates and furnaces which
are made of this metal. The metal is introduced into
the mould while it is fluid, or in the ftate of fufion, and
increafing in bulk as it cools, the minute cavities of
the mould are more accurately filled. This increafe
of bulk, as in the cafe of water when it becomes folid,
is alfo afcribed to a determinate arrangement of the
parts of the metal, or to cryftallization.
11. On the expanfive property of bodies depends
the conftruftion of the thermometer, which is employ¬
ed for the meafurement of the relative temperatures
of bodies. The invention of this inftrument is gene¬
rally afcribed to Sanftorio, an Italian phyfician, who
lived about the beginning of the 17th century, al¬
though it is faid by fome, that thermometers were
made by Drebel, a Dutch phyfician, and that they
were common in Holland, and even in England, be¬
fore Sandlorio was known in thefe countries.
In the thermometer of Sanflorio, the expanfive
power 01 air was employed to meafure the tempe¬
rature. His thermometer is conftrufted in the fol¬
lowing manner. A tube of glafs of 18 inches or
two feet in length, open at one end, is blown into
a ball at the other. When the ball is heated, the
air within is expanded, and wdiile the air is thus ex¬
panded, if the open end of the tubr be immerfed in a
veffel filled with any coloured fluid; as the internal
air cools, and is diminifhed in bulk, the liquid will rife
in the tube by the preffure of the external air on the
furface of the liquid in the veffel. A fcale of equal
degrees was then applied to the whole length of the
tube, and the thermometer w^as conftrufted. To af-
certain the heat of any body, as for inftance the hand,
it was applied to the ball, and if this temperature
459
Caloric.
196'
I S T R Y.
was greater than the medium in which the apparatus
was placed, the internal air was rarefied, and confe-
quently depreffed the furface of the coloured liquid in
the tube. The number of degrees of this depreflion
was obferved and compared in different experiments.
As for inftance, the difference of temperature of the Imperfect
body at different periods, to afcertain which, it is
faid, it was employed by the inventor. But the inac¬
curacy of this inftrument will be obvious; when we con-
fider that it depended, not only on the preflure, but
alfo on the temperature of the atmofphere. 197
This defeat in the air thermometer was remedied by Improved
Mr Boyle, and by the Florentine academicians, nearly
at the fame time ; and they thought ot employing other
fluids. The firft that was ufed was fpirit of wine,
which contrafting and expanding more than water at
the fame temperature, and not liable to be frozen by
cold, was found to be much more convenient. Quick-
filver w7as fome time afterwards employed in the fame
way. The ball of the glafs, and part of the tube,
was filled with the fluid, when the open extremity of
the tube was clofed. When heat was applied to the
ball, the fluid within expanded, and contrafted by
cold, without being influenced by the preffure of the
atmofphere, as in San&orio’s thermometer. But ftill
this thermometer was very imperfeff, for wTant of de¬
terminate points in the fcale, by which different ther¬
mometers might be compared together. This wTas firft
pointed out by Sir Ifaac Newton, and after various
improvements, it was brought to its prefent ftate of per-
fe&ion. , ip8
The method of conftrufting Fahrenheit’s thermo- Fahren-
meter, which is now in general ufe in this country, is t^1€r'
the following : A fmall ball is blown on the end of a ni0aieter*
glafs tube, of a uniform width throughout. The ball
and part of the tube are then to be filled with quickfilver
wdiich has been previoufly boiled to expel the air. The
open end of the tube is then to be hermetically feal-
ed (m). The next object is to conftruft the fcale. It
is found by experiment, that melting fnow or freezing
water, is always at the fame temperature. If therefore,
a thermometer be immerfed in the one or the other,
the quickfilver will always ftand at the fame point.
It has been obferved, too, that water boils under the
fame preffure of the atmofphere at the fame tempera¬
ture. A thermometer therefore, immerfed in boiling
water, will uniformly ftand at the fame point. Here
then are two fixed points from which a fcale may be
conftru£ted, by dividing the intermediate fpace into
equal parts, and carrying the fame divifions as far
above and below the two fixed points as may be want¬
ed. Thus, thermometers conftrufted in this way may
be compared together; for if they are accurately
made, and placed in the fame temperature, they will
always point to the fame degree on the fcale.
The fluid that is now generally employed is quick¬
filver, and it is found to anfvver beft, becaufe its ex-
panfions are moft equable. The freezing point of
Fahrenheit’s thermometer is marked 3 2°, and the
reafon of this is faid to have been, that this artifl:
3 M 2 thought
(m) This is done by heating the end of t|ie tube with the flame of a lamp, and by clofing it while the glafs
isfoftened.
460
C H
Caloric, thought that he had produced the greateft degree of
-—v 1 cold by a mixture of fnow and fait j and the point at
which the thermometer then flood in this temperature,
was marked zero. The boiling point in this thermo¬
meter is 2 l 2°, and the intermediate fpace between the
boiling and freezing points is therefore divided into
I So0. This is the thermometer that is commonly ufed
in Britain.
There are three other thermometers employed in
different countries of Europe, which differ from each
other in the number of degrees between the freezing
and boiling points.
Reaumur’s thermometer was generallyufed in France
before the revolution, and is flill employed in differ¬
ent countries on the continent. The freezing point
in this thermometer is marked zero, and the boiling
point 8o°. To convert the degrees of Reaumur’s ther¬
mometer to thofe of Fahrenheit, the following is the
E M I S T R Y.
199
Reaumur’s.
formula.
X 9
Reaum. •—- + 3 2:
200
Celiius.
X 9
mometer into thofe of Fahrenheit j Cel. ——- S2 —
Caloric.
Fahr. that is multiply
the degrees of Reaumur by 9, divide by 4 and add
32. This gives the correfponding degrees on Fahren¬
heit’s fcale.
The thermometer of Celfius has the fpace between
the freezing and boiling points divided into ioo°. The
boiling point is ioo*, and the freezing point zero.
This thermometer is ufed in Sweden. The thermometre
centigrade, now ufed in France, has the fcale divided
in the fame way. To convert the degrees of this ther-
Fahr. # 2ot
In Delifle’s thermometer, which is ufed in Ruffia, Delifle’s.
the fpace between the boiling and freezing points is
divided into 150° j but the degrees are reckoned
downwards. The boiling point is marked zero, and
the freezing point 150°. To reduce the degrees of
this thermometer under the boiling point to thofe of
Fahrenheit. Del. 212= Fahr. and above the
5
X 6
boiling point. Del.   212 = Fahr.
Such then are the principles and mode of conftru61ion
of the thermometer 5 an inftrument which has been of
the utmoft importance in enabling us to difcover many
of the properties and effe£ls of caloric, as by it only
we can afcertain with accuracy the relative tempera¬
tures (n). _ 202
l 2. It has been an obje£t of confiderable intereft and Quantity of
importance to afcertain the quantity and rate of expan- expanlion,
lion in bodies. Among folid bodies the quantity of
expanfion is very fmall, fo that a nice apparatus is ne-
ceffary to afcertain it. But it appears that the ratio
of this expanlion is equable, or nearly fo. The refults
of experiments made by Mr Smeaton and fome other
philosophers upon this fubjeft, will be feen in the fol¬
lowing table.
203
Of different
metals.
Temperature.
32
212
White heat
Piatina.
120,000
120,104
Antimony.
120,000
120,130
Steel
I 20,000
120,147
123,428
Iron.
120,000
120,151
I 21,500
Call Iron.
120,000
122,571
Bil'muth
I 20,000
120,167
Copper. Gaft Brafs.
120 OOO
120,204
J 20,000
120,000
Brals Wire
1 20,000
120,232
Temperature.
Tin.
3 2
212
120,000
120,298
Lead.
Zinc.
120,000 I 20,000
120,344 1120,355
Hammer¬
ed Zinc.
I 20,000
120-373
Zinc 8.
Tin r.
120,000
I 20,123
Lead 2.
Tin x.
I 20,000
I 20,301
Brafs 2.
Zinc 1.
120,000
I 20,247
Pewter
I 20,000
120,274
Copper 3.
Tin x.
120,000
I 20,218
204
Of glafs.
The rate of the expanlion of glafs, which is a mat¬
ter of conliderable importance, has been afcertained
by M. de Luc, and is exhibited in the following table :
Temperature.
305
Of liquids.
32
50°
70°
100
120
150
167
190
212
100,000
100,006
100,014
100,023
100,033
100,044
100,056
100,069
100,083
13. The expanlion of liquid bodies is greater than
that of folids, but it is not equable with equal addi¬
tions of temperature. It has been obferved, that thofe
liquids which are moft readily brought to the flate of
vapour, or whofe boiling point is loweft, expand moft.
With the fame given temperature, the expanlion of
water is greater than that of mercury, and the expan¬
lion of alcohol is greater than that of water. The
boiling point of water, is lower than that of mercury,
and the boiling point of alcohol is lower than that of
water j from which it would appear, that the expan¬
lion of liquids is nearly in the inverfe ratio of their
boiling temperatures, and this expanfion feems to in-
creafe with the temperature \ that is, the nearer a liquid
is to that point of temperature at which it boils, the
greater is the degree of expanfion by the addition of
caloric 3 and the farther it is from the boiling tem¬
perature, the fmaller is the increafe of bulk by the ad¬
dition of caloric. The following table exhibits the
ratio of expanfion of feveral liquids, as they have been
afcertained by different philofophers.
Table
(n) For meafuring high degrees of temperature, the pyrometer of Wedgwood is employed, which will be
defcribed under the earth alumina.
Caloric.
CHEMISTRY.
Table of the Rate of Expanfion of different Liquids from 3 2° to 212°.
461
Caloric.
Temp.
32
40
5°
Bo
70
80
90
100
110
120
130
140
150
160
170
180
190
200
212
Mercury.
IOOOOO
100081
IOO183
IOO304
100406
100508
1006 ro
100712
100813
100915
101017
101119
IOI220
101322
101424
101526
101628
101730
101835
Linfeed
Oil.
IOOOOO
102760
107250
Sulphuric
Acid.
99752
IOOOOO
100279
100558
100806
101054
101317
101540
101834
102097
102320
102614
102893
103116
103339
103587
103911
Nitric
Acid.
Water.
995I4
100000
100486
100990
101530
102088
102620
103196
103776
104352
105132
Oil of
Turpent.
IOOO23
IOOO91
IOOI97
IOO332
100694
100908
101404
102017
103617
IO4577
IOOOOO
100460
100993
101471
101931
102446
102943
103421
103954
104573
Alcohol.
IOOOOO
100539
101105
101688
102281
102890
103517
104162
All gafes 14. It has been proved by experiment that all gafe-
expand e- ous bodies undergo the fame expanfion, with the fame
quably. addition of heat. This has been afcertained by the
ingenious experiments of Mr Dalton and M. Gay-Luflfac.
The increafe of bulk of fome elaftic fluids from 3 2° to
212°, as determined by the latter, will be feen in the
following table :
* Ann- dt
Chim. vol.
xliii. p. l67«
Atmofpheric air 100
parts, increafed
Hydrogen gas
Oxygen gas
Azotic gas
37-5°
37.52 difference -\-0.2
37.48 —  —0.02
37.49   O.OI
*.
In other experiments he found, that the expanflon
of the vapour of water and of ether correfponded with
the expanfion of other gafes ; and he remarks, that
this property of the equable dilatation of the vapour of
ether and water, and the gafes, with the fame degrees
of temperature, depends not on the peculiar nature of
the vapours and gafes, but folely on their elaftic
ftate.
Mr Dalton’s experiments (hew that the expanfion of
air is very nearly equable. It appears, how;ever, that
the rate of expanfion diminilhed as the temperature in¬
creafed. The expanfion from 550 to I32^°, which in¬
cludes 77-5-0, was 167 parts*, but the expanfion from
l32-|0to 212°, the next 77t° was onty parts,
which was nine parts lefs than the firft. The fame
philofopher obferves, that the refults of feveral experi¬
ments wrhich he made upon hydrogen gas, oxygen gas,
carbonic acid gas, and nitrous gas, correfpond wnth
thofe on atmofpherical air, not only in the total ex¬
panfion, but in the gradual diminution of it in amen¬
ding. Small differences were obferved, but they ne¬
ver exceeded fix or eight paits in the whole amount
325 ", and differences to this amount, he adds, will
take place in common air, when not freed from aque-
1
ous vapour, which, he fays, was the fituation of his
faflitious gafes.
2. Of Fluidity.
207
I. Wm have now feen the effects of caloric in ex-Change of
panding bodies, when it is accumulated in them, ftate.
When a folid body, as a piece of iron, is expofed to a
high temperature, it is enlarged in bulk ; and when
the additional quantity of caloric with which it had
combined is withdrawn, it returns to its former dimen-
fions •, but when ftill greater additions are made to
moll: bodies, it is not merely a change of bulk that
takes place, but a total change of their proper-
ties.
All matter exifts, either in the ftate of folid, of li¬
quid, or in the ftate of vapour. Moft bodies, by the
addition or the abftraftion of caloric, are convertible from
one of thefe ftates into another. Let us take water
for an example. Ice is water in the folid ftate. When
a mafs of ice has received a proper quantity of caloric,
it affumes the liquid ftate ; and, rvhen this liquid has
received another portion of caloric, it is changed into
the ftate of vapour. But if this vapour is deprived of
a certain portion of caloric, it returns to the ftate of
liquid or that of water } and when this water is de¬
prived of another portion of caloric, it becomes folid,
or is converted into ice.
Thus it appears, that a folid body may be convert¬
ed into a liquid by means of caloric 5 and that a liquid
may be converted into an elaftic fluid by the fame
means. This feems to be a general law, to which
there are but few exceptions. Some bodies may be
converted into all the three ftates, as water ; others,
as fpirit of wine, exift only in the fluid ftate, and there
are fome folid bodies which are not convertible into
the ftate of liquid j but thefe exceptions are fo few,
that it has been fuppofed the fame effeft would follow,
■were
tempera¬
ture
eop
In fome in-
ftant a ne¬
on fly.
210 '
In others
gradually.
462 C H E M I
Caloric, were tliefe bodies expofed to a proper degree of tempe¬
rature.
f,. The temperature at which thefe changes are ef¬
fected, is invariably the fame in the fame body. Thus,
at the fame a mafs of ice is converted into the ftate of liquid or of
degree of water, when it is expofed to a temperature above 320 j
and water, when it is raifed to the temperature of
212°, aflumes the ftate of vapour or of fteam. But
although this temperature is conftant in the fame bo¬
dies, it varies greatly in different bodies. Thus, fpi-
rit of wine and ether are converted into vapour at a
very low temperature, while mercury and the fixed
oils, to undergo this change, require a temperature
far above that which is neceffary for the converfion of
water.
3. Some bodies are inftantaneoufly converted from
the folid to the liquid ftate. Thus ice, when the tem¬
perature is raifed, paffes immediately from the folid to
the fluid ftate. Other bodies undergo a gradual
change. They firft become foft, as in the inftance of
melting wrax, and pafs through the different degrees
of foftnefs, till at laft they become perfe£fly fluid.
4. It may perhaps now feem furprifing, that phe¬
nomena which were fo familiar fhculd have exifted fo
long without the true explanation of the changes which
bodies undergo, in paffmg from the folid to the liquid
or vaporous ftate, or from the fluid to the folid ftate.
The want of inftruments to meafure accurately the re¬
lative degrees of temperature at which thefe changes
take place, might perhaps be one caufe of the unfuc-
cefsful inveftigations of philofophers on this fubjeft.
But even after the invention and improvement of the
thermometer, it was long before the fecret, and we
may add, Ample caufe of thefe wonderful effe&s, was
fully afcertained. It was referved for the fagacity of
Dr Black to give the true explanation. The era of
the difcovery of this law, of fuch univerfal application
to the phenomena of nature, may be regarded as one
of the moft important in the hiftory of chemical fcience.
Dr Black was always diftinguilhed for caution and
precifion in all his views j and as the progreflive fteps
by which this celebrated philofopher w'as led to afcer-
tain the true caufe of fluidity afford us a fine ex¬
ample of Ample and elegant inveftigation, we fliall de¬
tail the experiments by which it was eftablifhed in his
own wTords.
5. After ftating that the caufe of fluidity which had
been formerly given was unfatisfaftory, and inconfift-
ent with the phenomena, he obferves that “ thefe phe¬
nomena, when attentively confidered, fhew that flui¬
dity is produced by heat, in a very different manner
from that which was commonly imagined j a manner,
howrever, which, when underftood, enables us to ex¬
plain many particulars relating to heat or cold, which
appeared in the former view of the fubjecft, quite per¬
plexing and unaccountable.
“ Fluidity was univerfally confidered as produced by
fuppofed to a fmall addition to the quantity of heat which a body
beowing to contains, when it is once heated up to its melting
dition ofad‘ P°*nt > anc* t^lc returning of fuch body to a folid ftate,
as depending on a very fmall diminution of the quan¬
tity of its heat, after it is cooled to the fame degree ;
that a folid body, wdien it is changed into a fluid, re¬
ceives no greater addition to the heat within it than
syhat is meafured by the elevation of temperature indi-
I
211
Great dif-
covtry of
Dr Black.
212
Fluidity
caloric.
S T R Y.
cated after fufion by the thermometer $ and that, when Caloric,
the melted body is again made to congeal, by a dimi- “""v-'
nution of its heat, it fuffers no greater lofs of heat than
what is indicated alfo by the fimpie application to it of
the fame inftrument. 3x3
“ This was the univerfal opinion on this fubjeft, fo Inconfiftent
far as I know, when I began to read my lectures in w*tl1
the univerfity of Glafgowq in the year 1737. But I
foon found reafon to obje£l to it, as inconfiftent with
many remarkable fafts, when attentively confidered j
and I endeavoured to fhew, that thefe faffs are con¬
vincing proofs that fluidity is produced by heat in a
very different manner.
“ I {hall now defcribe the manner in which fluidity
appeared to me to be produced by heat, and wre fliall
then compare the former and my view of the fubjeff
with the phenomena. 2I^
“ The opinion I formed from attentive obfervation Caloric is
of the faffs and phenomena, is as follows. When ice, abforbed by
for example, or any other folid fubftance, is changing follcl.s be“
into a fluid by heat, I am of opinion that it receives aflu^2
much greater quantity of heat than what is perceptible
in it immediately after by the thermometer. A great
quantity of heat enters into it, on this occafion, with¬
out making it apparently w armer, when tried by that
inftrument. This heat, however, muft be thrown in¬
to it, in order to give it the form of a fluid $ and I af¬
firm, that this great addition of heat is the principal,
and moft immediate caufe of the fluidity induced.
“ And, on the other hand, when w^e deprive fuch a Fluids be-
body of its fluidity again, by a diminution of its heat, coming fo-
a very great quantity of heat comes out of it, while it ^ S'.ve out
is affuming a folid form, the lofs of which heat is not c^u0^c•
to be perceived by the common manner of ufing the
thermometer. The apparent heat of the body, as mea¬
fured by that inftrument, is not diminiflied, or not in
proportion to the lofs of heat which the body actually
gives out on this occafion j and it appears from a num¬
ber of fafts, that the ftate of folidity cannot be indu¬
ced without the abftraftion of this great quantity of
heat. And this confirms the opinion, that this quan¬
tity of heat, abforbed, and, as it w'ere, concealed in
the compofition of fluids, is the moft neceffary and im¬
mediate caufe of their fluidity.
** To perceive the foundation of this opinion, and
the inconfiflency of the former with many obvious fads,
wre muft confider, in the firft place, the appearances
obfervable in the melting of ice, and the freezing of
water.
If we attend to the manner in which ice and fnowpro^ ^
melt, when expofed to the air of a warm room, or the melting
when a thaw fueceeds to froft, we can eafily pereceive, ice and
that however cold they might be at the firft, they are ^reezing of
foon heated up to their melting point, or begin foonUater'
at their furface to be changed into water. And if
the common opinion had been well founded, if the
complete change of them into w'ater required only the
further addition of a very fmall quantity of heat, the
mafs, though of a confiderable fize, ought all to be
melted in a very few minutes or feconds more, the
heat continuing inceffantly to be communicated from
the air around. Were this really the cafe, the confe-
quences of it wTould be dreadful in many cafes; for,
even as things are at prefent, the melting of great
quantities of fnow and ice occafions violent torrents,
. and
C H E M
Caloric, and great inundations in the cold countries, or in the
“"Y—^ rivers that come from them. But, were the ice and
fnow to melt as fuddenly as they muft neceffarily do,
were the former opinion of the a&ion of heat in melt¬
ing them well founded, the torrents and inundations
would be incomparably more irrefiftible and dreadful.
They would tear up and fweep away every thing, and
aI7 that fo fuddenly, that mankind Ihould have great dif-
Melting of ficulty to efcape from their ravages. This fudden li¬
ke a very quefa&ion does not actually happen j the maffes of ice
flow pro- or fnow melt a very flow pr0grefs, and require a
long time, efpecially if they be of a large fize, fuch
as are the colleftions of ice, and wreaths of fnow,
formed in fome places during the winter. Thefe, after
they begin to melt, often require many weeks of warm
weather, before they are totally diffolved into water.
This remarkable flownefs with which ice is melted, en¬
ables us to preferve it eafily during the fummer, in the
ftru&ures called ice-houfes. It begins to melt in thefe,
as foon as it is put into them j but, as the building ex-
pofes only a fmall furface to the air, and has a very
thick covering of thatch, and the accefs of the exter¬
nal air to the infide of it is prevented as much as pof-
fible, the heat penetrates the ice-houfe with a flow
progrefs, and this, added to the flownefs with which
the ice itfelf is difpofed to melt, protrafts the total li¬
quefaction of it fo long, that fome of it remains to
the end of fummer. In the fame manner does fnow
continue on many mountains during the whole fummer,
in a melting ftate, but melting fo flowly, that the whole
of that feafon is not a fufficient time for its complete
liquefaCtion.
“ This remarkable flownefs with which ice and fnow
melt, ftruck me as quite inconfiftent with the common
opinion of the modification of heat, in the liquefaCtion
2l8 of bodies.
Foundation “ And this very phenomenon is partly the foundation
of the dif- of the opinion I have propofed j for if we examine
covery. what happens, we may perceive that a great quantity
of heat enters the melting ice, to form the water into
which it is changed, and that the length of time
neceffary for the collection of fo much heat from the
furrounding bodies, is the reafon of the flownefs with
which the ice is liquefied. If any perfon entertain
doubts of the entrance and abforption of heat in the
melting ice, he needs only to touch it j he wnll inftant-
ly feel that it rapidly draws heat from his warm hand.
He may alfo examine the bodies that furround it, or
are in contaCl with it, all of which he will find de¬
prived by it of a great part of their heat ; or if he
fufpend it by a thread, in the air of a warm room, he
may perceive with his hand, or by a thermometer, a
ftream of cold air defcending conftantly from the ice j
for the air in contaCl is deprived of a part of its heat,
and thereby condenfed and made heavier than the
warmer air of the reft of the room; it therefore falls
downwards, and its place round the ice is immediately
fupplied by fome of the warmer air; but this, in its
turn, is foon deprived of fome heat, and prepared to
defcend in like manner ) and thus there is a conftant
flow of warm air from around, to the fides of the ice,
and a defcent of the fame in a cold ftate, from the
lower part of the mafs, during which operation the
ke muft neceffarily receive a great quantity of heat.
“ It is, therefore, evident that the melting ice re-
I S T R Y. 463
ceives heat very faft, but the only effeCl of this heat Caloric. ^
is to change it into water, which is not in the leaft ^ ^
fenfibly warmer than the ice was before. A thermo-
meter, applied to drops or fmall ftreams of water, im- meter does
mediately as it comes from the melting ice, will point not indi-
to the fame degree as when it is applied to the ice it-
felf, or if there is any difference, it is too fmall toforbed>
deferve notice. A great quantity, therefore, of the
heat, or of the matter of heat, which enters , into the
melting ice, produces no other effeCl but to give it
fluidity, without augmenting its fenfible heat} it ap¬
pears to be abforbed and concealed within the water,
fo as not to be difcoverable by the application of a
thermometer.
“ In order to underftand this abforption of heat
into the melting ice, and concealment of it in the
water, more diftinClly, I made the following experi¬
ments. # 230
“ The plan of the firft was, to take a mafs of ice, Proved by
and an equal quantity of water, in feparate veffels, °^exp^trsl"
the fame fize and fhape, and as nearly as poflible of the n:ic
fame heat, to fufpend them in the air of a warm
room, and, by obferving with a thermometer the ce¬
lerity with which the water is heated, ot receives heat,
to learn the celerity with which it enters the ice j and
the time neceffary for melting the ice being alfoat-
tendenS to, to form an eftimate, from thefe two data,
of the quantity of heat which enters the ice during its
liquefaCHon. _ 221
“ In order to prepare for this experiment, I chofe Firft expe-
two thin globular glaffes, four inches diameter, andnment-
very nearly of the fame weight: I poured into one of
them five ounces of pure water, and then fet it in a
mixture of fnow and fait, that the water might be
frozen into a fmall mafs of ice. As loon as frozen, it
was carried into a large empty hall, in which the air
was not difturbed or varied in its temperature during
the progrefs of the experiment ^ and in this room the
glafs was fupported, as it wTere, in mid air, by being
fet on a ring of ftrong wire, which had a tail iffuing
from the fide of it five inches long, and the end of
this tail was fixed in the mod projefting part of a read¬
ing delk or pulpit; And in this fituation the glafs
remained until the ice was completely melted.
“ When the ice was thus placed, I fet up the other
globular glafs precifely in the fame fituation, and at the
diftance of 18 inches to one fide, and into this I pour¬
ed five ounces of water, previoufly cooled, as near to
the coldnefs of melting ice as poflible, viz. to 33®,
and fufpended in it a very delicate thermometer, the
bulb of which being in the centre of the water, and
the tube being fo placed, that without touching the
thermometer, I could fee the degree to which it point¬
ed. I then began to obferve the afcent of this ther¬
mometer, at proper intervals, in order to learn with
what celerity the water received heat, ftirring the
water gently with the end of a feather about a minute
before each obfervation. The heat of the air, examin¬
ed at a little diftance from the glaffes, was 47* of
Fahrenheit’s fcale.
“ The thermometer affumed the temperature of the,
water in lefs than half a minute, after which, the rife
of it was obferved every five or ten minutes, during
half an hour. At the end of that time, the wTater w as
grown warmer than at firft, by ^
degrees j and the
tpmnerature
464
Caloric.
mnm\
C H E M I
temperatui'e of it bad rifen to the 40th degree of Fah¬
renheit’s fcale.
“ The glafs with the ice was, when firft taken out
of the freezing mixture, four or five degrees colder
than melting fnow, which I learned by applying the
bulb of the thermometer to the bottom of it $ but
after fome minutes, it had gained from the air thofe
four or five degrees, and was juft beginning to melt,
which point of time was then noted, and the glafs
left undifturbed ten hours and a half. At the end of
this time, I found only a very fmall and fpongy mafs
of the ice remaining unmelted, in the centre of the
upper furface of the water, but this alfo was totally
melted in a few minutes more j and, introducing the
bulb of the thermometer into the water, near the fides
of the glafs, I found the water there was warmed to
the 40th degree of Fahrenheit. From this it appears,
that when a confiderable part of the ice was melted,
and the quantity of water around it wras increafing,
the heat was not tranfmitted through this water to
the remaining ice altogether fo faft as it was receiv¬
ed by the water j -which is eafily underftood, if we
confider that the diftance between the remaining ice
and the external furface of the veffel through which
the heat entered, was gradually increafing, and that
heat ahvays requires time to pafs through bodies,
or to be communicated from one part of them to a-
nother.
“ It appears, therefore, from this experiment, that
it was neceffary that the glafs with the ice receive
heat from the air of the room during 21 half-hours,
in order to melt the ice into water, and to heat that
water to the 40th degree of Fahrenheit. During all
this time, it was receiving the heat, or matter of heat,
with the fame celerity (very nearly) with which the
water-glafs received it daring the fingle half-hour in
the firft part of the experiment. For, as the water re¬
ceived it with a celerity which was diminifhing gra¬
dually during that half-hour, in confequence of the di¬
minution of difference between its degrees of heat
and that of air ; fo the glafs with the ice alfo receiv¬
ed heat with a diminilhing celerity, which correfpond-
ed exaflly with that of the water-glafs, only that the
progreffion of this diminution was much more flowq
and correfponded to the whole time which the water liir-
roundingThe ice required to become w'armed to the 40th
degree of Fahrenheit. The whole quantity of heat,
therefore, received by the ice-glafs during the 21 half-
hours, wras 21 times the quantity received by the wa¬
ter-glafs during the fingle half-hour. It was, there¬
fore, a quantity of heat, which, had it been added
to liquid water, wmuld have made it warmer by
4°—33 X 21, or 7 x 21, or 147 degrees. No part of
this heat, how'ever, appeared in the ice water, except
8 degrees j the remaining 139 or 140 degrees had been
abforbed by the melting ice, and were concealed in the
water into which it was changed.
“ The communication of heat to the melting ice
was eafily perceived, during the whole time of its ex-
pofition, by feeling the ftream of cold air w'hich de-
fcended from the glafs.
il T his experiment was an analyfis of the manner in
which ice is melted by the heat of the air in ordinary
circumftances.
44 But another obvious method of melting ice occur-
S T R Y,
red to me, in which it would be ftill more eafy to per- Caloric,
ceive the abforpticn and concealment of heat, and this ~ v"*—'
was the aftion of warm water. 222
“ When hot and cold water are mixed together, Secord ex-
the excels of heat contained in the hot water is equally Foment,
diftributed in an inftant through the whole mixture,
and raifes the temperature ot it according to the great-
nefs of the excels of temperature, and the proportion
which tire hot water bore to the cold. If the quanti¬
ties of hot and cold water are equal, the tempera¬
ture is the middle degree between that of the hot
and that of the cold. No part of the heat difappears
on this occafion, fo far as we can perceive, but the in-
tenfity of it only is diminilhed, by its being diffuled
through a larger quantity of matter. It was, there¬
fore, obvious, that if a quantity of heat is abforbed,
and difappears in the melting of ice, this would eafily
be perceived when the ice is melted with warm W'a-
ter.
“To make this experiment, I firft froze a quan¬
tity of water in th.e neck of a broken retort, in order
to have a mafs of ice of an oblong form.
“ At the fame time-I heated a quantity of water,
nearly equal in weight to the ice, in a very thin glo¬
bular glafs, the mouth of which w'as fufficiently wide
to take in the piece of ice. The water w'as heated
by a fmall fpirit of wine lamp applied to the bottom
of the glafs ; it was alfo ftirred with the end of a
feather, and a thermometer hung in it.
“ While the water was heating, the mafs of ice was
taken out of the mould in wFich it had been formed,
and wras expofed to the air of a temperate room, until
it was perceived to be beginning to melt over the whole
of its furface.
“ I then put a woollen glove on my left hand, and
taking hold of the ice, I wuped it quite dry with a li¬
nen towel, laid it in the fcale of a balance on a piece of
flannel, and haftily counterpoifed it with fand in the
oppofite fcale, that I might examine the weight of it
afterwards 5 and I immediately plunged it into the hot
W’ater, and extinguilhed the lamp at the fame time.
The lamp being fmall, the heat of the water had
been increafing very flowly, and had almoft ceafed to
increafe } and being examined immediately before I
put the ice into it, thq. temperature was found to be
juft 190 degrees. The ice was all melted in a few
feconds, and produced a mixture, the temperature of
which was 53 degrees.
“ The weight of the ice, when put into the hot wa¬
ter, was feven ounces three drams and a half. The
weight of the glafs, with the whole mixture in it, w'as
16 ounces, feven drams, and feven grains. The weight
of the glafs alone was nearly one ounce.
“ In confidering this experiment, we may overlook
quantities lefs than half a dram, or 30 grains, and reckon
the qaamities of the different articles, by the number
of half-drams in each.
Thus the weight of the ice w7as 119 half-drams.
 Hot water 135
————— Mixture 254
   Glals alone 16
“ The melting of the ice was effedled, not only by
the heat of the hot water, but alfo by that of the
glafs. And, by other experiments, I learned that 16
parts of hot glafs have no more power in heating cold
bodies,
Caloric.
223
Caloric is
abforbed.
* Black's
Left. vol.
P- 125-
224
Called la¬
tent beat.
C H £ M
bodies, than eight parts of equally hot water *, we may
'therefore fubftitute, in place of the 16 half-drams of
warm glafs, eight half-drams of warm water, which,
added to the above quantity of warm water, make up
143 half-drams.
“ The heat of this warm w^ater was 190 degrees, that
is 1 <;8 hotter than the ice ; and if this heat had abated
in the mixture only in confequence of the quantity and
coldnefs of the ice, and if nothing had happened when
the ice w^as put in, but merely a communication of
this heat, and an equal diltribution of it through the
mixture, the temperature of the mixture Ihould have
been 158, viz. the excefs of heat in the warm water,
multiplied by 143, the quantity of the wYarm matter,
and divided by 262, the quantity of the whole, which
gives 86.
“ The mixture fliould have been 86 degrees warmer
than melting ice *, but it was found only .21 degrees
warmer. Therefore a quantity of heat has difappear-
ed, which, if it had remained in a fenfible date, would
have made the wdrole mixture and glafs warmer by 65
degrees than they were aftually found to be. But
this quantity of heat would be fufficient for increafing,
by 143 degrees, the heat of a quantity of water, equal
in weight to the ice alone. It was, however, abforb-
ed by the ice, without in the lead increafing its fenfi¬
ble heat (o).
“ The refult of this experiment coincides fufficiently
with that of the former; the difference is not greater
than what may be expected in fimilar experiments,
and might arife from the accident of the central parts
of the mafs of ice being colder than the furface, by
one or two degrees.
“ I have, in the fame manner, put a lump of ice in¬
to an equal quantity of water, heated to the tempera¬
ture 176, and the refult wms, that the fluid was no
hotter than water juft ready to freeze. Nay, if a lit¬
tle fea fait be added to the water, and it be heated on¬
ly to 166 or 170, we {hall produce a fluid fenfibly
colder than the ice was in the beginning, which has
appeared a curious and puzzling thing to thofe unac¬
quainted with the general fa£l.
“ It is, therefore, proved that the phenomena which
attend the melting of ice in different circumftances,
are inconfiftent with the common opinion which was
eftabliftied upon this fubjeft, and that they fupport the
one which I have propofed
i. 6. Thefe experiments fhew clearly and incontrover-
tibly, that the converfion of ice into water is owing to
the abforption of a certain portion of caloric } and that
the quantity of caloric abforbed is equal to what would
have raifed the temperature of a body which remained
unchanged, for inftance as water, 140°. Thefe iqcf*
therefore, have difappeared, (Tor no increafe of tem¬
perature is indicated by the thermometer), have been
abforbed by the ice, and are neceffary to reduce it to
the liquid ftate. This portion of caloric which had
thus difappeared, Dr Black called Intent hent^ becaufe
in this ftate of combination its prefence was not indi-
Vol. V. Part II.
I S T R Y, 465
cated by the thermometer. By others this has been Caloric,
called the caloric of fluidity.
7. In the progrefs of thefe inveftigations, experi- 22-5
ments were made on other fubftances, which clearly ments on
ftiewed that their fluidity is owing to the fame caufe. other bo-
Thefe experiments were made on wax, tallow, fperma-dies prove
ceti, fulphur, alum, nitre, and fome of the metals, d'f tame
The late ingenious Dr Irvine, the pupil of Dr Black,
and who effentially aflifted him in many of his experi¬
ments, afeertained the quantity of caloric which was
neceffary for the fluidity of the following fubftances;
which, when compared with that of ice, will fhew
that the quantity of the caloric of fluidity incieafes
with the temperature at which the body is converted
into the liquid ftate.
Spermaceti, 14819.
Bees wax, 175.
Tin, 500 *. * Black':
8. Dr Black farther obferves on the operation of^fj^0"
this caufe, that there is reafon to think, that not only aaff
the fluidity of bodies, but even the foftnefs of fuch asSoftnefs
are rendered plaftic by heat, depends on a quantity of^.™^-
heat combined with them, in the form of latent heat ^ewing ty0
and that the malleability and duftility of metals de-the fame
pend upon the fame caufe. For, while they are ex-caufe.
tended under the hammer, they become warm, and in
fome cafes very hot } but at the fame time they be¬
come rigid, and are no longer malleable. They have
loft their toughnefs and foftnefs. To reftore this, they
muft be annealed or made hot in the fire, and allowed
to cool. Thus, they recover their malleability, of
which they may be again deprived by a fecond ham¬
mering. . 2*7
9. The temperature at which folid bodies begin to be Tempera-
converted into the liquid ftate, is always conftant
and till they are raifed to this temperature^ no change dies be_
takes place. Water in the folid ftate, or ice, alwrays come fluid
remains unchanged till it is placed in a temperature conftant.
above 320. This point, which is called the Melting
point, is conftant in the fame body, but is very differ¬
ent in different bodies. The following table exhibits
the melting point of a number of folid bodies.
Lead, 5940
Bifmuth, 576
Tin, 442
Sulphur, 212
Wax, 142
Spermaceti, 133
Phofphorus, 100
Tallow, 92
Oil of anife, 50
Olive oil, 36
Ice, 32
Milk, 30
Vinegar, 28
Blood, 25
Oil of bergamot, 23
Wines, 20
3 N Oil
(o) “ Thefe two experiments, and the reafoning which accompanies them, were read by me in the Piulofo
phical Club, or Society of Profeffors and others in the Univerfity of Glafgow, m the year 1762,
466
Caloric.
228
Water
changed
into va¬
pour.
229
Boiling,
what.
230
Boiling
point con-
ftant;
231 _
but varies
with pref-
fure.
C H E M
Oil of turpentine, 140
Sulphuric acid, 36
Mercury, 39
Liquid ammonia, 46
Ether, 46
Nitric acid, 66
3. Of Vapour.
1. If, after a mafs of ice is converted into water or
the liquid ftate, the application of heat be continued
to that water, it undergoes other changes, and exhi¬
bits very different phenomena. If the temperature be
railed fufficiently high, the water becomes agitated
writh an inteftine motion, and if it is fupplied with a
fufficient quantity of caloric, the whole of the Water is
diffipated. This agitation of the water, it is wrell
known, is called in common language, boiling.
2. As folid bodies which are capable of being con¬
verted into the liquid ftate by an increafe of caloric,
have a certain determinate temperature, fo, many of
thofe bodies which are capable of affummg the form of
an elaftic fluid, undergo this change, only when they
are raifed to a certain temperature. Some liquids, in¬
deed, affume the form of vapour at all temperatures,
which is the cafe with w'ater, with volatile oils, fpirits
of wine and ether. This change is called
evaporation ; but there are others which remain fixed
and unchanged till the temperature is railed to that
point at which they boil. Boiling is nothing elfe but
the rapid converfion of the liquid into vapour. I he
heat being applied to the bottom of the veffel, wdiich
contains the liquid, the particles at the bottom firft af¬
fume the elaftic form ; and as they rife through the li¬
quid, caufe it to be violently agitated. This boiling
point, under the fame preffure, is always the fame in
the fame liquid ; and however ftrong the heat that may
be applied, or however long it may be continued, the
temperature of the liquid, in open veffels, never rifes
above this point. The boiling point of water, for in-
ftance, is 212°, and it never becomes hotter; on the
contrary, if the fame heat be continued, the w’hole is
diffipated, and converted into vapour.
Table JJjswing the boiling point of feveral liquids.
Ether, 98°
Ammonia, 140
Alcohol, 176
Water, 212
Muriate of lime, 230
Nitric acid, 248
Phofphorus, 5 C4
Oil of turpentine, 560
Sulphur, 570
Sulphuric acid, 5Q0
Linfeed oil, 600
Mercury, 660
3. But this boiling point is found to vary confidera-
bly, and this variation depends on the preffure on the
furface of the liquid. When the preffure is diminifh-
ed, liquids boil at a lower temperature •, but when this
preffure is increafed, they require a higher tempera¬
ture to produce boiling. Water boils at a low tempe¬
rature on the top of a high mountain, or in the va¬
cuum of an air pump, where the preffure is greatly di-
2
I S T R Y.
minifhed ; but when it is confined in clofe veffels, as Caloric,
in Papin’s digefter, the temperature may be raifed to -y—/
30.00 or 400° without boiling. 232
4. The general law which was difeovered by Dr Law of la-
Black, of the converfion of folids into liquids, was id- *e,,t h^a*
fo applied by him to account for the change of liquids exten e
into elaftic fluids. This was proved by the following
experiments.
“ Experiment i.—I procured (fays Dr Black) fome
cylindrical tin-plate vefiels, about four or five inches
diameter, and flat-bottomed. Putting a fmall quan¬
tity of water into them, of the temperature 50°, I fet
them upon a red-hot kitchen table, that is, a caft-iron
plate, having a furnace of burning fuel below it, tak¬
ing care that the fire (hould be pretty regular. After
four minutes, the water began fenfibly to boil, and in
20 minutes more, it was all boiled off. I his experi¬
ment was made 4th Oftober 1762.
“ Experiment 2.—Two flat-bottomed veffels, like the
former, were fet on the iron plate, with eight ounces
of water in each, of the temperature 50°. They both
began to boil at the end of three and a half minutes,
and in eighteen minutes more, all the water was boil¬
ed off.
“ Experiment 3.—The fame veffels were again fup¬
plied with 12 ounces of water in each, alfo of the
temperature 50°. Both began to boil at the end of fix
and a quarter minutes, and the water was all boiled
off, from the one in 28 minutes, and from the other
in fomething more than 29.
“ I reafoned from thele experiments in the following
manner : The veffels in the firft experiment received
162 degrees of heat in four minutes, or degrees
each minute. If we, threfore, fuppofe that the heat
enters equally faft during the whole ebullition, we muft
fuppofe that 810 degrees of heat have been abforbed
by the water, and are contained in its vapour. Since
this vapour is no hotter than boiling water, the heat
is contained in it in a latent ftate, if we confider it on¬
ly as the caufe of warmth. Its prefence is fufficiently
indicated, however, by the vaporous or expanfive form
which the water has now acquired. 2^3
“ In experiment fecond, the heat abforbed, and ren- Quantity
dered latent, feems to be about 830. ^ ^ v^ur
“ In the third experiment, the heat abforbed feems to m ' T0’3 * * * * * * * 11
be fomewhat lefs, viz. about 750. The time of riling
to the boiling heat, in experiment third, has nearly the
fame proportion to that in experiment firft, that the
quantities of water have. The deficiency, therefore,
in the heat abforbed, has been probably only appa¬
rent, and arifing from irregularity in the fire. Upon
the whole, the conformity of their refults with my con-
jefture was fufficient to confirm me in my opinion of
its juftice. In the courfe of further experiments made
both by myfelf and by fome friends, and in which the
utmoft care was taken to procure a perfeft uniformi¬
ty in the heat applied, the abforption was found ex¬
tremely regular, and amounted at art average to about
810 degrees. _ 234
“ There are other cafes where this abforption appears Other
in a much more lingular manner. I put into a very proofs of
ft rone phial, about as much water as half filled it ™,°n5:ab“
and I corked it clofe. The phial was placed in
fand-pot,. which was gradually heated, until the fand
and phial were feveral degrees above the common ya-
porihe
vapour.
C H E M
Caloric, porii'ac point of water. I was curious to know what would
’**■”—v—-J be the effett of fuddenly removing the preflure of the air,
which is well known to prevent water from boiling. The
Water boiled a very Ihort while, but the ebullition gradu¬
ally decreafed, till it was almoft infenfible. Here the
formation of more vapour was oppoled by a very Itrong
preflure, proceeding from the quantity of vapour al¬
ready accumulated, and confined in the upper part of
the phial, and from the increafed elafticity of this va¬
pour, by the increafe of its heat. When matters were
in this date, I drew' out the cork. Now, according
to the common opinion of the formation of vapour by
heat, it was to be expected that the whole of the water
■would fuddenly affume the vaporous form, becaufe it
was all heated above the vaporific point. But I was
beginning by this time to expedf a different event, be¬
caufe I could not fee w’hence the heat was to be fup-
plied, w’hich the water mufl: contain when in the form
of vapour. Accordingly, it happened as I expefted ;
a portion only of the water wras converted into vapour,
which rufhed out of the phial with a conliderable ex-
plofion, carrying along with it fome drops of water.
But, wThat wTas moft interefting to me in this experi¬
ment w’as, that the heat of what remained was redu¬
ced in an inftant to the ordinary boiling point. Here,
therefore, it was evident, that all that excefs of heat
which the water had contained above the boiling point,
was fpent in converting only a portion of it into va¬
pour. This is plainly inconfiftent with the common
opinion, that nothing more is neceffary for water’s
exifting in a vaporous form under the preffure of the
atmofphere, than its being raifed to a certain tempera¬
ture. The experiment makes it more probable, that
if the influx of heat could at that inftant have been
prevented, it wrould have remained in the form of wa¬
ter, although raifed, in a very lenfible degree, above
the boiling temperature.
“ I wTas anxious to learn whether the heat which dif-
appeared in this experiment was in an accurate pro¬
portion to the quantity of vapour produced, or the
quantity of wratcr that had difappeared. But the
drops of water that were hurried along by the explofion
without being converted into vapour, made it impofli-
ble for me to afcertain this with any tolerable accuracy,
although I repeated the experiment feveral times.
The caloric “ This experiment was afterwards made by my friend
-abforbed in Mr Watt, in a very fatisfa&ory manner. His ftudies
proportion fof. improvement of his fteam-engine, gave him a
40 th»-» f great intereft in every thing relating to the produ&ion
vapour/ f of fteam. He put three inches of water into a fmall
copper digefter, and, fcrewing on the lid, he left the
fafety-valve open. He then fet it on a clear fire of
coaks, and after it began to boil and produce fteam, he
allowed it to remain on the fire half an hour, with the
valve open. Then, taking it off the fire, he found
that an inch of water had boiled away. In the next
place, he reftored that inch of water, ferewed on the
lid, and fet it on the fire j and as foon as it began to
boil, he (hut the fafety-valve, and allowed it to remain
on the fire half an hour as before. The temperature
of the whole was many degrees above the boiling
point. He took it off the fire, and fet it upon afhes,
and opened the valve a very fmall matter. The fteam
ruftied out with great violence, making a (hrieking
noife for about two minutes. When this had ceafed,
I S T R Y.
he ftiut the valve, and allowed all to cool. When
he opened it, he found that an inch of water was con-
fumed.
“ It is reafonable to conclude from this experiment,
that nearly as much heat was expended during the
blowing of the fteam-pipe, as had been formerly ex¬
pended in boiling off the inch of water. For, before
opening the valve, the temperature was many degrees
above the boiling point, and all this dilappeared with
the vapour. The lame inference may be drawn from
the time that the digefter continued upon the fire with,
the valve Unit, becaufe we may conclude that the
heat was entering nearly at the fame rate during the
whole time. It is plain, however, that the experiment
is not of fuch a kind as to admit of nice calculation ;
but it is abundantly futficient to Ihew that a prodigious
quantity of heat had efcaped along with the particles
of vapour produced from an inch of water. The water
that remained could not be hotter than the boiling
point, nor could the veffel be hotter, otherwife it would
have heated the water, and converted it into vapour.
The heat, therefore, did not elcape along with the va¬
pour, but in it, probably united to every particle, as
one of the ingredients of its vaporous conttrtution. And
as ice, united with a certain quantity of heat, is water }
fo water, united with another quantity of heat, is fteam
or vapour * Blaei't
The following experiment made by the late Dr vqI. i.
vine of Glafgow, at the defire of Dr Black, and re-P- 1 ^
corded by the latter, is a ftill farther confiimation ofQjn£rnie(|
the general fa£l of the converfion of liquids into elaftic by Dr Ir-
fluids, by combining with caloric. vme’
“ Five meafures (each containing 4 lb« 5 oz* ant^
6 dr. avoirdupois) ot water, of the temperature 520,
were poured into a fmall ftill in the laboratory. The
fire had been kindled about 40 minutes before, and was
come to a clear and uniform Hate. The ftill was let in¬
to the furnace, and, in an hour and 20 minutes, the
firft drop came from the worm } and in three hours
and 45 minutes more, three meaiures of water rvere
diftilied, and the experiment ended. The relrigera-
tory contained 38 meafures of water, of which the
temperature, at the beginning of the experiment, was
5 20. When one mealure had come over, the water
in the refrigeratory w'as at 76°. When two had come
over, it was at 100° > and when three had come over,
itwasatI23°.
“ In this experiment, the heat, which emerged from
three meaiures of water, had railed the temperature of
the water in the refrigeratory from 52° to 1230, or
710. Now 3 is to 38 as 71 to 899-f, and the heat
would have raifed the three meafures 899! degrees in
its temperature, if this had been poftible without con¬
verting it into vapour. The heat of the vapour from
which this emerged, was 212°, or l6o° more than
that of the water. Taking this from 899°, there re¬
mains 7390, the heat contained in the vapour in a la¬
tent ftate.
“ But this muft be fenfibly lefs than the truth. Dur¬
ing the experiment, the veffels were very warm—the
head of the ftill as hot as boiling water, and the refri¬
geratory gradually riling from 520, which was within a
degree or twTo of the temperature of the air of the la¬
boratory, to 1230. A very confiderable portion of the
latent heat of the fteam muft have been carried off by
3 N 2 thc
468 C H E M
Caloric, t’ne air in contact with a conhdcrable fmface, fome of
  v   which was exceedingly hot. A great deal mull alfo
have been carried off in the fleam which arofe very
fenfibly from the water in the refrigeratory, towards
the end of the experiment. Mr Irvine alfo obferved,
that, during the diflillation, the temperature of the w'ater
which ran from the worm was about 11° hotter than the
water in the refrigeratory. The fleam, therefore, at
a medium, was not i6o° hotter than the water which
ran from the worm, but 1250, its mean temperature
being about 87°. This conlideration alone will make
the latent heat of the fleam not lefs than 774 degrees,
without any allowance for wafte.
“ Some companion may alfo be made between the
heat expended in the produdlion of the fleam, and
that which emerges during its condenfation. The time
which elapfed during the railing of the temperature of
the five meafures of water from 520 to 212°, that is
1600, was one hour and 20 minutes, or 8c/,—and
•225' elapfed during the boiling off of three meafures.
Therefore, fince 8c> is to 225 as 160 to 450, as much
heat was expended as would have railed the live mea¬
fures 450° in temperature. This would have raifed
three meafures 750° above the boiling heat already
produced. This gives 750 for the latent heat of the
fleam, befides what was unavoidably loft by communi¬
cation to the ambient air, and what was expended in
* LeB. vol. heating the veffels
i. p. 173. In fome experiments made by Mr Watt, rvho alfo
237 aflifted Dr Black in conducing thefe invaluable ex-
Peam efti Periments. ^ appears that the latent heat of fleam is
mated by from 9000 to 950”. This he difcovered by obferving
Watt. the quantity of caloric which was abforbed by the wa¬
ter in its converlion into fleam or vapour, and the
quantity given out, when that vapour returned to the
g ftate of water.
By Lavoi- The value of the latent heat of fleam, eftimated by the
her. experiments ofM. Lavoifier,amountsto more than iooo°.
Thus is this general law eftablilhed, that all li¬
quids are converted into elaftic fluids, by combining
with a certain portion of caloric. This portion of ca¬
loric is not indicated by the thermometer, and is there¬
fore faid to be latent heat, as we already mentioned •,
but when the elaftic fluid returns to the liquid ftate, it
again becomes fenfible, and precifely the fame quan-
tity is extricated which was abforbed.
Elasticity 6. It is an obje£I of fome importance to afcertain the
ofallva- elaftic force of vapour, and the ratio of the increafe of
pour the giafticity by increafe of temperature. The elafti-
tbat^oTwa- c^y vaPour which is formed by a liquid boiling in
ter with the open air, is equal to the preffure of the atmofphere ;
the fame and it has been afcertained by the experiments of Mr
increafe of Ddtcm and of M. Gay-Luffac, that the elafticity of
tu™Pera" all elaftic fluids is the fame with that of the vapour of
water, with the fame increafe or diminution of tem¬
perature from the boiling point. If then, the boiling
point of any liquid be known, the elafticity of its va¬
pour may be difcovered, by comparing it with the elaf¬
ticity of the fleam of water, the fame number of de¬
grees above or below the boiling point. In the
following table, conftrufted by Mr Dalton from his ex'-
periments and calculations, the elafticity of the vapour
of water is given for every temperature from 40° to
3 2 50. To find the elafticity of the vapour of ether at
I S T R Y.
40° below its boiling point, which is 98°, take 40°
from 98°, there remains 58°, and the fame number
from 212® the boiling point of water, there remains
17 2°, oppofite to which number in the tabic is 12.73,
which is the elafticity of the fleam of water at 17 2°,
and alfo the elafticity of the vapour of ether at 58°.
Caloric.
Tablf. of the Force of Vapour from Water in every tem¬
perature, from that of Congelation of Mercury, or 40°
below "Zero of Fahrenheit, to 3 iff. f Manch.
Mem. vol.
CHEMISTRY.
Caloric.
Table Continued.
Table Continued.
469
Caloric.
Force of
Temper- Vap. in
ature. inches of
Mercury.
299
3°°
3°I
302
3°3
Temper¬
ature.
1 IO.64 308°-
111.81 309 -
112.98
114.15
115.32
116.50
117.68
3°4 —'
3°5 —
^06 118.86
307   120.03
310
311
312
313
3T4
315
316
Force of
Vap. in
inches of
Mercury.
Force of
Temper- Vap. in
ature. inches of
Mercury.
121.20
122.37
123.53
I 24.69
125.85
127.CO
128.15
129.29
I3°*43
317° 131.57
1318  132.72
1319  ^S-86
1320  135-00
321  
322  137-28
323  138.42
324  139-56
325  140.70
Sect. III. Of the Motion of Caloric.
240
1. It appears that the motion of caloric, when it is Velocity of
not interrupted, is equal in velocity to that of light. “
When therefore it is emitted by one body, it moves on tj)at. 0f
with this velocity till it is received by another. This has light,
been called the tranfmljfon or radiation of heat. This 241
radiation or feparation of heat_ from any body, arifesKadiated'
from the force with which it is connecied with that
body being dimimlhed } that is, when a greater quan¬
tity of caloric is accumulated in that body than it can
contain. The experiments of Dr Herfchel {hew, that Reir.idleti
heat is radiated, refrafted and reflefted, in the fame
manner as light. I he refleflion of caloric has
been proved by the experiments of Mr Pnffet formerly
mentioned. But caloric is communicated from one
body to another by direft contaft of thefe bodies. 244
2. It is well known that a cold body brought into
contact with a warm body, in a certain time becomes 'J
hot ; but this does not take place inftantaneoufly ; and
the time neceffary for one body to receive caloric from
another, or for the different parts of the fame body to
acquire the fame, temperature, varies accoiding to the
nature and ftate of thefe bodies. This is called the
conduBing power of bodies.
3. But as different bodies have different degrees
of affinity for caloric, or contain different propor¬
tions of it, it muff be feparated or abforbed with 245
greater or lefs facility. The motion of caloric there-More ra-
fore, in thefe different circumffances, will be confi- ^
derably varied in its celerity. This may be proved
by direct experiment. If one extremity of two fub-
flahces of different properties, as for inffance, a rod of
iron and another of wood, be put into the fire, and the
hand brought into contaa with the other extremity, the
rod of iron will loon be heated too much for the hand
to bear, while the rod of wood will not have its tem¬
perature greatly increafed. This fhews, that there is
a fmaller quantity of caloric carried through the wood;
or, in other words, the iron is a better conduftor than
the wood. 2^6
4. All folid bodies are condu&qrs of caloric, but Good «n-
they poffefs this povTer in very different degrees.
Thofe bodies which conduft caloric with facility are
called good condu&ors, but thofe through which it
paffes
47®
Caloric.
247
Bad con-
duiSors.
248
Their ufe.
249
Metals the
belt con-
dudtois.
^ Journ. de
dPhyf._ 1789.
250
Conducing
power of
woods.
f Annal. de
Chim- vol.
xxx. p. 43.
C H E M
pafies with difiiculty or very (lowly, are faid to be bad
conductors. The motion of caloric from one body
to another, or through the fame body, is not altoge¬
ther in proportion to their denfities, as might be fup-
pofed from the inftance of the communication of calo¬
ric through wood and iron, juft mentioned Calo¬
ric is conduced very (lowly through a more porous
fubftance, fuch as a mafs of cork, of wrool, of feathers,
or furs. It is on account of the (lownefs with which
heat is conducted in thefe fubftances, that fome of them
are employed in the colder feafons of the year, or in
cold countries, as materials for clothing. The heat
being (lowly conducted through fuch fubftances, they
prevent the heat of the body from being diffipated, or
cut off the communication between the warm body and
the cold air0 And thus we fee a wife provifion of na¬
ture, in furni(hing all animals wdiich are inhabitants of
the colder regions of the earth, with a thick covering
of fur or feathers. According to the experiments of
Count Rumford, the conducting power of fur, feathers,
filk, and wool, diminilhes in proportion to the finenels
of their texture.
Metallic fubftances are the beft conductors of calo¬
ric ; but among the metals it would appear that there
is confiderable variety in their conducting power, and
this is not in proportion to their denfity, as appears
from the experiments of Dr Ingenhoufz on the follow¬
ing metals, which are fet down in the order of their
conducting power *,
Silver,
Gold,
Copper,
Tin,
Platina,
Iron,
Steel,
Lead.
A fet of experiments were made on the conducting
power of different woods, by Profeffor Mayer of Er¬
langen, of which the following are the refults, compar¬
ed with the conducting power of water f.
Water,
Ebony,
Crab apple,
A(h,
Beech,
Hornbeam,
Plum tree,
Female oak,
Pear tree,
Birch,
Oak,
Pitch pine,
Alder,
Pine,
Fir,
Lime tree,
10.0
21.7
27.4
38.0
32.1
32,3
32- 5
32.6
33- 2
34- i
36- 3
37- 5
38- 4
38.6
38 9
39°
The experiments of Guyton (hew, that the con¬
ducting power of charcoal is to that of fine fand nearly
t Ibid. vol. in the proportion of 2 to 3
xxvi.p. 227* y. Fluid bodies, as well as folids, are conductors of
I S T R Y.
caloric 5 but they are found to conduCt it fo (lowly, Calorte.
that it was at firft fuppofed, they did not poffefs this
power at all; that is, that the caloric w’as not conduCt- fluids are
ed from particle to particle in fluids, fimilar to what condu&ors;
happens in folid bodies. This opinion feemed to be fup-
ported by the nature and conftitution of fluids, in which
the particles have free motion among each other, fo
that when one fet of particles acquire an additional
quantity of caloric, their fpecific gravity is neceflarily
diminifhed, and they naturally change place with thofe
other particles of the fluid which have been lefs heat¬
ed and are confequently heavier. 'I hefe different ap¬
pearances which were obferved in the heating of fluids
led Count Rumford, who made many ingenious expe¬
riments on this fubjeCt, to conclude, that fluids are
heated, or conduft caloric, in a different manner from
folids. In a fpirit of wine thermometer, w’hich was
placed in a window to cool, he obferved the fluid in
the tube in rapid motion. There were two currents
going in different diredtions, the one afcending, and
the other defcending. The defcending current oc¬
cupied the Tides of the tube, and the afcending current
the middle. The currents were owing to the change
in the fpecific gravity of the particles, wdiich being
heated became lighter, and rofe to the top 5 the heavier
particles at the fame time defcending. The particles
which afcended having reached the (ides or top of the
tube, gave out their caloric, became fpecifically
heavier, and again fell to the bottom. The motion of
the currents was confiderably increafed by the appli¬
cation of a cold body to the Tides of the tube. The
count alfo repeated the experiment with linfeed oil,
and alfo with water, in the latter of which he diffolv-
ed potafh, to bring its fpecific gravity to that of am¬
ber, fmall pieces of which he introduced, to obferve
the currents more diftindlly. Thefe experiments were
followed with the fame refult. When the temperature
was increafed or diminifhed, the currents were fet in
motion, and only ceafed when the temperature be¬
came equal to the furrounding bodies.
In profecuting this fubjeft, the count made other
experiments, to afcertain how far the heating or cool¬
ing of fluids is affe&ed by a difference of fluidity. The
thermometer wdiich he employed in thefe experiments,
has a copper bulb and a glafs tube, and it wras filled
with linfeed oil. This was placed in the centre of a
brafs cylinder, and the fpace between the fides of the
cylinder and the thermometer, was 0.25175. The
thermometer being fecured, the cylinder was filled
wuth 2276 grs. of pure water, and held in melting
fnow, till the thermometer fell to 320. It wras then
immerfed in boiling water, and the thermometer rofe
from 320 to 200° in 597". The caloric which raifed
the thermometer muft have been communicated to it
through the w'ater in the cylinder. The experiment
was then varied, by boiling 192 grs. of (larch in the
water in the cylinder. The thermometer now requir¬
ed 1109" to rife from 32° to 200®. The fame experi¬
ment was repeated by mixing 192 grs. eider down with
the fame quantity of water, and alfo with a quantity of
dewed apples. The refults of thefe experiments will
be feen in the following tables $. § Rumfuri^
Effay 7.
Time
Caloric.
* Vol. iv.
P- 5?9-
f Ibid, oc¬
tavo, vol. i.
p. 165.
t Vol. v.
P- 373-
2SZ
but worfe
than folids.
C H E M I
Tttne the Caloric was in pajjing into the Thermometer.
Tempera¬
ture.
Through
the water
and Starch.
rherm. rofe
from 31°
to 2000 m
Therm, roie
8o°, V'Z.
ftom 8^°
to i6o°,in
Seconds.
IIO9
Through the
Water and
Eiderdown.
Seconds.
949
34i
269
Through
ftewed
Apples.
Seconds.
1096^-
335
Through
pure
Water.
Seconds.
597
172
Time the Caloric was in pa [fing out of the Thermometer.
Tempera¬
ture.
Therm, fell
from zoo0
to 400
Therm, fell
8o°, viz.
from 1600
to 8o°, in
Through
the Water
and Starch.
Through the
Water and
Eiderdown.
Seconds.
1548
468
Through
itewed
Apnles.
Seconds.
1541
460
Seconds.
I749-I-
Through
pure
Water.
Seconds,
io32
520
277
The fubftances which were added to the water in
thefe experiments, by diminilhing its fluidity, had the
effeft of retarding the internal motions or currents by
which the caloric is conduced through fluids. Thus,
when ftarch was mixed with water, it required nearly
double the time to raife the thermometer to the fame
degree, as with pure water. From thefe, and from
fome other experiments, Count Rumford concluded,
that fluid bodies are heated in a different manner from
folids ; that caloric is not communicated through fluids
from particle to particle, but that all the particles in¬
dividually come in contadl with the heating body, and
this is fuppofed to be the caufe of the currents which
a*e obferved during the heating of fluids.
5. Fluids no doubt acquire great part of their tem¬
perature in this manner ; but it has been clearly prov¬
ed by the experiments of others, that they are alfo
conductors of caloric exaftly the fame way as folid bo¬
dies, but in an inferior degree. T his has been efta-
blifhed in the moft fatisfa&ory manner by the experi¬
ments of Dr Thomfon * and Mr Murray-}-, which
were publilhed in Nicholfon’s Journal 5 and alfo by
another fet of experiments by Mr Dalton, which were
publiftied in the Manchefler Memoirs X- By tbefe ex¬
periments it is demonftrated, that fluids conduCt calo--
ric from the furface downwards ; which could not be
the cafe, were it only communicated through them by
the afeending currents of particles, in the way Count
Rumford fuppofed : but they are worfe conductors of
caloric than folids 5 that is, it paffes through them
much more flowly.
Sect. IV. Of the Distribution of Caloric.
If a number, of bodies be expofed to different'
S T R Y.
temperatures, and then be all placed in the fame tem¬
perature, or brought into contaft with each other,
they acquire in a certain time the fame tempera- ^
rature. Thus, if one body be raifed to the tempera- All bodies
ture of 200°, another to that of ioo°, and a third to acquire the
the temperature of 6o° ; and if thefe three bodies be1;ime ,eni.-
placed m the temperature of 8o°, they all indicate, m'he f;ime
a fhort time, the fame temperature. The bodies which medium.
wrere at the temperature of 200° and loo0 are reduced
to 8o°, and the temperature of the body at 6o° rifes
to the fame. This is called the difribution, or the
equilibrium of caloric. To whatever degree bodies
are heated or cooled, they all acquire in time, the
temperature of the furrounding medium, as it is indi¬
cated by the thermometer. It may therefore be re¬
ceived as a general law, that all bodies which commu¬
nicate freely with each other, and are fubjeEl to no ine¬
quality of external aBion, acquire the fame tempera¬
ture. _ > 254
1. Bodies are deprived of caloric, not only by radia-Radiation
tion from their furfaces, but it is alfo conduded by not the Iblf?
thofe bodies with which the heated body comes in con-^”^ “
tad, and this depends greatly on the nature of the fur¬
rounding cold body. The experiments of Profeflbr
Pidet and Count Rumford, however, (hew, that ra¬
diation is not the only caufe. By thofe of the former
it appeared, that hot bodies fufpended in the vacuum
of an air-pump, cooled more flowly than in the open
air ; and by thofe of the latter, the cooling was ftill
flower in the Torricellian vacuum. 255
2. The time requifite for the heating or cooling of Good con.
bodies depends much on their conduding power. A coqj
fubrtance which is a good condudor of caloric cools rapidiya
much more rapidly than a bad condudor. Mercury
and water heated to the fame temperature cool in ve¬
ry different times ; the mercury cools more than twice
as fall as the water in the fame circumftances. The
time of the cooling of fluids has been confidered as
nearly in the inverfe ratio of their conduding power. 256
3. This equal diftribution of caloric was-attempted Diftril)u-
to be explained by Boerhaave, Mufchenbroeck, and of ca-~
others, by fuppofing that there is an equal quantity °^pjajne(| ..
caloric in every equal meafure of fpace, however that Boerhaave,.
fpace might be filled up with different bodies, and that &c.
thefe bodies floated, as it wrere, in this caloric, from
this equal diftribution of caloric in fpace, they con¬
cluded that there was an equal quantity of caloric in
all bodies, becaufe, whatever was the denfity or differ¬
ent circumftances of bodies, they always indicated the
fame temperature to the thermometer. A cubic foot
of gold, and a cubic foot of air, according to this
theory, contained the fame quantity of caloric. ^ ^ . a(,7
P'ofeffor Pidet gave another explanation of this By Pidet..
phenomenon. He fuppofed that the accumulation of
caloric in a body increafed the repulfive force between
its particles, by the diminution of the diftance between
them. By the adion of this repulfive force, the par¬
ticles are driven off in all diredions. This repulilon
continues to ad till it is oppofed by a new torce, which
is the force of repulfion between the particles of calo¬
ric feparated front another body j and, till tbefe two
forces acquire the fame intenfity, the particles of calo¬
ric continue to feparate from the hotter body. herr
the two forces are balanced, the bodies are of the5
fsune temperature. Thus, if two bodies of different*
temperatures
472
Caloric.
CHEMISTRY.
* EJfai fur
Ic Feu,
chap. i.
258
His theory
unfatisfac-
tory.
259
Prevoft’s
theory
f fourn- de
Fhyf, April
J791.
| Geneva,
1792.
5 Phil.
‘Tranf.
1S02.
temperatures are brought into contaft with each other,
the repulfive force of the particles of caloric in. the
hotter body is the greateft, and therefore the particles
tend to feparate from each other } but the repulfion
between the particles of the colder body, being lefs,
they come nearer each other. The caloric from the
hotter body continues to feparate, and to enter the
colder body, till the two forces exa&ly balance each
other, and then the temperature is the fame *. But
this theory, with all its fimplicity and ingenuity, be¬
ing unfatisfa&ory in accounting for the equilibrium of
temperature, has been given up, even by its author.
4. Another theory has been propofed by M. Pre-
volt, profeffor of philofophy at Geneva. “ Accultom-
ed,” fays he, “ for a long time, to confider this fub-
je£t in a different view from what had been formerly
taken of it, I endeavoured to draw the attention of
naturalifts to this inveftigation, in a memoir on the
equilibrium of caloric -f-, and in my refearches on heat
In thefe works, I believe it was firlt propofed to fub-
flitute a moveable equilibrium in place of the immove¬
able equilibrium, the exiftence of which had been ge¬
nerally admitted.
“ On this hypothefis, it is equally eafy and fatifac-
tory to account for the refledlion of cold, as. for that
of heat. I conlider it indeed a chara&eriftic of its
truth ; for thefe two fafts being of the lame kind, the
theory that wall account for the one, is applicable to
the other. Before I proceed to ftate in a few words
the principle of this theory, I may premife, that I had
the fatisfattion of feeing it adopted by M.. Pi£tet and
others, who are well qualified to judge of it.
“ Caloric is a diferete, agitated fluid : each particle
of free caloric moves with immenfe velocity ; one par¬
ticle moves in one diredtion, and anothei particle
moves in another, fo that a heated body gives out ca-
lorific rays in all directions \ and thefe particles aie fo
far feparated from each other, that two or more cur¬
rents may crofs each other, as is the cafe with light,
without mutual difturbance in their co.urfe. Conceiving
this to be the conftitution of caloric, if we fuppofe two
contiguous fpaces in which it abounds, there will be
continual changes between thefe fpaces. If in the two
fpaces caloric abounds equally, the exchanges will be
equal •, there will be an equilibrium. If one of the
fpaces contain more caloric than the other, the ex¬
changes wdll be unequal. The cooleft will receive
more particles of caloric than it gives out, and after a
fufficient time, the continual repetition of thefe changes
will reftore the equilibrium §.
“ From thefe principles may be deduced all the
laws of the increafe and diminution of temperature.
Let us fuppofe a body placed in a medium hotter than
itfelf, and that this medium has_ a conftant tempera¬
ture. We may confider the caloric of the medium as
compofed of two parts, the one equal to that. of the
body, and the other equal to the difference of the two.
With regard to the firft, the exchanges are.equal j be¬
tween the body and the medium there is an equili¬
brium; The excefs of the heat of the medium may
then only be confidered •, and relatively to this excefs
the body is abfolutely cold. Let us fuppofe that in
one fecond the body receives thJs caloric *, at the
end of the firft fecond the excefs will be no more than
-fg-: the /o this new excefs will pafs into the body
1
during the next fecond j and the excefs will be reuu-
Caloric*
ced to -!%- of ; and in purfuing this, at the end of '
the third fecond, the excefs will be (^)3, and fo on :
fo that, conformably to the oblerved law, the.times in¬
creafe in arithmetical progreffion, and the differences
decreafe in geometrical progreffion. In the fame way
may be eafily deduced the law of the. cooling of
a body placed in a medium colder than itfelf. And
thus the true theory of heat, founded on fadls totally
different from thofe by which Richmann eftabliffied
this law, neceffarily leads us to it *. * Phil.
’ ‘Tranf.
Sect. V. Of the ^VAh’ti'tr of Caloric in Bodies.
We have now treated in the form: - fe&ions of the
effefts of caloric, of its motion, and of its diffufion in
bodies j we are next to confider the quantity of calo¬
ric which thefe bodies contain. I his iubject has^ occu¬
pied the attention and fpeculations of many pbilofo-
phers. In thefe fpeculations, two objefts were kept
in view, the one to afeertain the whole quantity of ca¬
loric which a body contains, and the otner the quan¬
tity of caloric neceffary to raile different bouies to the
fame temperature. This laft is ufually called fpecifc
caloric.
Of Specific Calobic.
260
1. If one lb. erf water at the temperature of I oo° be explained,
mixed with another lb. of water at the temperature of
50°, they will very foon acquire the fame temperature,
which will be the mean of the two temperatures. The
pound of water at loo0 will give out 250, and the
pound of water at 50° will receive 250, which brings
both to the temperature of 750.
2. But if we take one pound of water at too0, and
one pound of mercury at 50°, the temperature, after
mixing the water and the mercury, will not be 75°,
the medium temperature in the former cafe. On the
contrary, when the mixture is made, the temperature
will be'found to be 88°. The water, therefore, has.
loft only 12°, and the mercury has gained 38°. If
this experiment be reverfed, and one pound of water
at 50° be mixed with a pound of mercury at ioo> the
temperature of the mixture will be found to be.only
62® ; fo that in this cafe the. mercury has given out
38°, and the water has received only 12°. .In this,
experiment, therefore, it appears clearly, that different
quantities of caloric are neceffary to increafe or dimi-
nifti the temperature of different bodies for, the quan¬
tity of caloric which raifes water 120, raifes mercury
no lefs than 38®. This quantity of caloric which bo¬
dies require to raife them to the fame temperature, is
called fpecifc caloric. . . „ r
3. “ It was formerly a common luppofition,. lays
Dr Black, “ that the quantities of caloric required to
increafe the heat of different bodies by the fame num¬
ber of degrees, were dire&ly in proportion to the quan¬
tity of matter in each j and therefore, when the bo¬
dies were of equal fize, the quantities of caloric were
in proportion to their denfity. But very foon after I
began to think of this fubjeft, in the year 1760, I
perceived that this opinion was a miftake, and that the
quantities of heat which different kinds of matter muft
receive, to reduce them to an equilibrium with one
another, or to raife their temperature by an equal num-
1 ber
Caloric.
* Black's
LeB. V. i.
p. 79.
261
Dr Black’s
method.
f Lea. v. i.
p. 506.
262
Dr Craw¬
ford’s
263
Mr
Wilcke’s
C II E M
ber of degrees, are not in proportion to the quantity
of matter in each, but in proportions widely different
to this, and for which no general principle or reafon
can yet be affigned This differencewas firft point¬
ed out by Dr Black, which he dates in the above ob-
fervations* and he dillinguifhed it by the term capacity
of bodies for heat. Dr Black’s method, which is given
by Profelfor Robifon, is the following.
“ Dr Black ertimated the capacities, by mixing the
two bodies in equal mafl'es, but of different tempera¬
tures ; and then dated their capacities as mverfely pro¬
portional to the changes of temperature of each by the
mixture. Thus, a pound of gold, of the temperature
150°, being fuddenly mixed with a pound of water, of
the temperature 50°, raifes it to 550 nearly : There¬
fore the capacity of gold is to that of an equal weight
of water as 5 to 95, or as 1 to 19 j for the gold lofes
950, and the water gains 50.
“ It will be mod convenient to compare all bodies
with wrater, and to exprefs the capacity of water by
unity, or to call it 1. Let the quantity of the water be
W, and its temperature °iu. Let the quantity of the
other body be B, and its temperature b. Let the tem¬
perature of the mixture be m. The capacity of B is
, or, when the water has been the hotter of
B X b—m
W x w—m
the two, the capacity of B is ~r  '-r-. In other
’ r J BX'«—b
words, multiply the weight of the water by its change
of temperature. Do the fame for the other fubfance.
Divide the firf produdl by the fecond. The quotient is
the capacity of the other fubfance, that of water being
accounted 1 f (?)•”
4. This fubjeft was dill farther profecuted by other
philofophers, particularly by Dr Irvine of Glafgow,
Dr Crawford of London, and Profeffor Wilcke of
Stockholm.
The method wdiich was employed by Dr Crawford
was dmilar to that of Dr Black. Two fubdances
which were of different temperatures, were uniformly
mixed $ the change of temperature produced on each
was obferved, and this was conddered as inverfely pro¬
portional to its fpecidc caloric.
Mr Wilcke has afcertained the fpecidc caloric of
many metals, by a fet of very ingenious experiments,
which were conduced in the following manner. The
metal which was the fubjeft of the experiment, was
drd accurately weighed. The quantity employed was
generally a pound. It was then fufpended by a thread,
Vol. V. Part II.
1 s r R Y.
plunged into a veffel of tin plate filled with boiling
water, and allowed to remain till it reached a certain
temperature indicated by the thermometer. A quan¬
tity of water at the temperature of 3 2°, exactly equal
in weight to the metal, was put into another veffel of
tin plate. The metal was then immerfed in this vef¬
fel, and fufpended in it fo as to be kept free from the
ddes and bottom. The temperature, at the moment
when the metal and water were reduced to the fame,
was obferved. The fpecidc caloric of the metal was
then deduced by calculation from the change of tem¬
perature. He drft calculated what the temperature
would have been, if a quantity of w'ater of equal weight
with the metal, and of the fame temperature, had been
added to the ice-cold water. The following is the
procefs.
Let M be a quantity of water at the temperature C,
m another quantity at the temperature c, and let their
common temperature after mixture be.r; according to a
, , MC-f-wc
rule demonftrated long ago by Rrchman, x— " jyl_|_,T *
In the prefent cafe the quantities of water are equal,
therefore M and m are each ~ 1 j C, the temperature
MC -\-mc
473
Caloric.
of the ice-cold water, — 32 : therefore
M+r
Now c is the temperature of the metal. There-
2
fore if 32 be added to the temperature of the metal,
and the w'hole be divided by 2, the quotient will ex¬
prefs the temperature of the mixture, if an equal weight
of water with the metal, and of the fame temperature
with it, had been added to the ice-cold water inftead of
the metal.
He then calculated what the temperature of the mix¬
ture would have been, if, inftead of the metal, a quan¬
tity of water of the fame temperature with it, and
equal to the metal in bulk, had been added to the ice-
cold water. As the weights of the ice-cold water and
the metal are equal, their volumes are inverfely as
their fpecific gravities. Therefore the volume of ice-
cold water is to a quantity of hot w’ater equal in
volume to the metal, as the fpecilic gravity of the me¬
tal to that of the water. Let M — volume of cold
water, m =r volume of hot water, g — fpecific gravity
of the metal, I — fpecific gravity of water 5 then
M
/» : M :: 1 -.g ; hence /« = — = (M being made =1)
3 O
i
g
£ f)ii Thefe experiments require the moft fcrupulous attention to many circumftances which may affeft the
tefult. 1. The mixture muft be made in a very extended furface, that it may quickly attain the medium tem¬
perature. 2. The ftuff which is poured into the other fttould have the temperature of the room, that no change
may happen in the pouring it out of its containing veffel. 3. The effeft of the veffel in which the mixture is
made muft be confidered. 4. Lefs chance of error will be incurred when the fubftances are of equal bulk.
5. The change of temperature of the mixture, during a few fucceftive moments, muft be obferved, in order to
obtain the real temperature at the beginning. 6. No fubftances fhould be mixed which produce any change of
temperature by their chemical adlion, or which change their temperature, if mixed when of the fame tempera¬
ture. 7. Each fubftance muft be compared in a variety of temperatures, left the ratio of the capacities ftrouid
be different in different temperatures. , #
« When all thefe circumftances have been duly attended to, we obtain the meafure of the capacities of differ¬
ent fubftances for heat.” Black's Lett. v. i. p. 506.
474
Caloric.
I S T R Y.
the temperature of the metal which would have raifed
the ice-cold water the fame number of degrees that the
metal did.
Now expreffes the fpecific caloric of the me-
c — N
Therefore if the fpecific gravity of tal, that of water being = i. For (neglecting the
C H E M
— Subftituting this value of m in the formula,
§’
MC-f-wc __ ^ -n ]\l — x and C = 32, x will
be = ^±5
the metal be multiplied by 32, and the temperature
of the metal be added, and the fum be divided by the
fpecific gravity of the metal -f-i, the quotient will ex-
prefs the temperature to which the ice-cold water
would be raifed by adding to it a volume of water
equal to that of the metal, and of the fame tempera¬
ture with it.
He then calculated how much water at the tempera¬
ture of the metal it would take to raife the ice-cold
Water the fame number of degrees which the metal
had raifed it. Let the temperature to which the metal
had raifed the ice-cold water be =N, if in the formula
MC+otc ^ ^ be made _ N> M = 1, C = 32, m
Caloric.
fmall difference occafioned by the difference of tempera¬
ture) the weight and volume of the ice-cold wrater are
to the weight and volume of the hot water as x to
^T~T3- and the number of particles of water in each
c—N
are in the fame proportion. But the metal is equal in
weight to the ice-cold water, it muff therefore contain
as many particles of matter } therefore the quantity of
matter in the metal muff be to that in the hot w’ater
^ But they gave out the fame quantity
-N
M-f-"*
.n , N—32
will be rr  rr
c—JN
Therefore if from the temperature
to which the ice-cold water was raifed by the metal
32 be fubtraaed, and if from the temperature of the
metal be fubtraaed the temperature to which it raifed
the water, and the firft remainder be divided by the
lafl, the quotient will exprefs the quantity of water of
as 1 to
c— ..
of caloric j which, being divided equally among their
particles, gives to each particle a quantity of caloric
inverfely as the bulks of the metal and water ; that is,
the fpecific caloric of the wTater is to that of the metal
N—32/
as 1 t07HN (R)'
It will now be proper to give a fpecimen or two of
his experiments, and the calculations founded on them,
as above defcribed.
Gold. Specific Gravity 19.040.
Num¬
ber of
experi¬
ments.
Tempe--
rature of
the me¬
tal.
163.4°
Temper,
to which
the metal
raifed the
water at
32J.
Temper, to which
it would have been
raifed by a quanti¬
ty of water equal
in weight and
heat to the metal.
Temper, to which
it would have been
raifed by water
equal in bulk and
temperature to the
metal.
Denominator of
the fraction
N—32
38.3°
97-7
144.5
127.4
118.4
103.1
37*4
88.25
3 6-5
79-7
36.05
75-
38.5550
37-58
36.68
36.15
35.6
65-75
3542
95
34-45
63.5
35.°6
-N.
1—N —
N—3*
the numerator
being 1.
19.857
I9.833
20.500
20.333
18.750
19.OOO
Mean 19.712
Lead.
f All thefe formulas have been altered to make them correfpond with Fahrenheit’s thermometer. They
are a good deal Ampler when the experiments are made with Celfius’s thermometer, as Mr Wilcke did. In 1.
the freezing point is zero ; and confequently inftead of 32 in the formula, o is always fubitituted.
Caloric.
C H E M I S T R Y.
Lead. Specific Gravity 11.456.
Num¬
ber of
experi¬
ments.
Tempe¬
rature of
the me¬
tal.
Temper,
to which
the ipe-
tal raifed
the wa¬
ter a*
3*°-
Temper, to which
the water would
have been raifed
by a quantity of
water equal in
weight and heat
to the metal.
186.8 38.3
181.40 37.85
165.2
163.4
136.4
I3I
126.5
107.6
94.1
374
37-4
36-5
36.05
36.05
35^5
34-7
Temper to which
the water would
have been raifed
by water equal in
hu k a: d tempera¬
ture to the metal.
IO9.4
106.7
98.6
97-7
84.2
44.425
43-473
Denominatorof
the fraction.
42.692
42.548
40.344
8l.?
79-25
69.8
63.05
39-947
39-585
38-339
36.985
c—N
N—32
23-57I
24.538
23.666
23-333
22.200
24.700
22.333
Mean 23.515
23.000
22.000
475
Caloric.
It is needlefs to add, that the laft column marks the
denominator of the fpecific caloric of the metal; the
numerator being always I, and the fpecific caloric of
water being 1. Thus the fpecific caloric of gold is
——. In exaftly the fame manner, and by taking
19.712
a mean of a number of experiments at different tempe¬
ratures, did Mr Wilcke alcertain the fpecific caloric of
*- Thow/m'sa number of other bodies. *
■CbimiJIry, 5. With the fame view, to afcertain the fpecific ca-
v. i. 314. loric of bodies, a fimple and ingenious apparatus was
contrived by Lavoifier and La Place. This inftrument
is called a calorimeter, or meafurer of heat. Its prin-
264 ciples and conftru&ion are the following :
Lavoilier’s “ If9 after having cooled, fays Lavoifier, any body
method. t0 t^e freezing point, it be expofed in an atmofphere
of 88.25° the body will gradually become heated,
from the furface inwards, till at laft it acquire the
fame temperature with the furrounding air. But, if a
piece of ice be placed in the fame fituation, the cir-
cumftances are quite different it does not approach
in the fmalleft degree towards the temperature of the
circumambient air, but remains conftantly at 32°, or
the temperature of melting ice, till the laft portion of
ice be completely melted.
“ This phenomenon is readily explained as, to melt
ice, or reduce it to water, it requires to be combined
with a certain portion of caloric, the whole caloric at¬
tracted from the furrounding bodies, is arrefted or fix¬
ed at the furface or external layer of ice which it is
employed to diffolve, and combines with it to form
water •, the next quantity of caloric combines with the
Lecond layer to diffolve it into water, and fo on fuc-
-ceCfively till the whole ice be diffolved, or converted
into water, by combination with caloric j the very laft
atom ftill remaining at its former temperature, becaufe
the caloric could never penetrate fo far, while any
intermediate ice remained to melt, or to combine
with. # -an
“ Upon thefe principles, if we conceive a hollow
fphere of ice at the temperature of 32° placed in an
atmofphere of 54 5°, and containing a fubftance at any
degree of temperature above freezing; it follows,
That the heat of the external atmofphere cannot pene¬
trate into the internal hollow of the fphere of ice;
and, That the heat of the body which is placed in
the hollow of the fphere cannot penetrate outwards be¬
yond it, but will be flopped at the internal furface, be¬
ing continually employed to melt fucceffive layers of
ice, until the temperature of the body be reduced to
32° by having all its fuperabundant caloric above that
temperature carried off to melt the ice. If the whole
water, formed within the fphere of ice during the re¬
duction of the temperature of the included body to
32®, be carefully collefted, the weight of the water
will be exaftly proportional to the quantity of caloric
loft by the body, in paffmg from its original tempera¬
ture to that of melting ice $ for it is evident that a
double quantity of caloric would have melted twice
the quantity of ice. Hence the quantity of ice melted
is a very exaft meafure of the proportional quantity of
caloric employed to produce that effeCl, and confe-
quently of the quantity loft by the only fubftance that
could poftibly have fupplied it.
“ I have made this fuppofition, of what would take
place in a hollow fphere of ice, for the purpofe or
more readily explaining the method ufed in this ipecies
of experiment, which was firft conceived by M- e a
2 O 2 * lace.
47 6
Caloric.
265
Apparatus
defcribed.
CHEMISTRY.
Place. It would be difficult to procure fuch fpheres of of the caloric loft by the fubftance fubmitted to experl- ^ Caloric,
ice, and Inconvenient to make ufe of them when got j ment. .
but, by means of the following apparatus, we have re- “ When the temperature of the atmofphere is only a
medied that defeft. few degrees above the freezing point, its heat can
« The calorimeter Is reprefented in Plate CXLII. fig. hardly reach the middle cavity, being arrefted by the
2. The capacity or cavity is divided into three parts, ice of the cover, and of the external cavity > but> if
which, for better diftinaion, I ffiall name the interi- the temperature of the air be under the degree of freez¬
er, middle, and external cavities. The interior cavi- ing, it might cool the ice contained m the middle ca-
ty ffff, into which the fubftances fubmitted to ex- vity, by caufing the ice m the external cavity to fall,
periment are put, is compofed of a grating or cage of in the firft place, below 32^ It is therefore effential
iron wire, fupported by feveral iron bars *, its open- that this experiment be carried on a temperature
ing or mouth LM, is covered by the lid HG, fig. 3. fomewhat above freezing : Hence, in time of froil, the
which is compofed of the fame materials. The mid- calorimeter muff be kept in an apartment carefully
die cavity b b b b, fig. 2. contains the ice which fur- heated. It is likewife neceffary that the ice employed EUm.
rounds the interior cavity, and which is intended to be be not under 320, for which purpofe it muft be pound-
melted by the caloric of the fubilances employed in the ed, and fpread out thin for fome time, in a place where
experiment. The ice is fupported by the grate m m the temperature is higher.
at the bottom of the cavity, under which is placed the 6. Tables of the fpecific caloric of bodies have been
fieve n n. given by Dr Crawford, Mr Kirwan, Bergman, Ga-
“ In proportion as the ice contained in the middle dolin,. and Meyer. The following are the relults of
cavity is melted, by the caloric difengaged from the their inveftigations.
body placed in the interior cavity, the water runs
through the grate and fieve, and falls through the conical ’Table of the Specific Caloric of various Bodies, that of
funnel c c d, fig. 2. and the tube x y, into a receiver. IVater being — 1.0000.
This water may be retained or let out at pleafure, hy
means of the ftop-cock u. The external cavity a a a a,
fig. 2. is filled with ice, to prevent any effeft upon the
ice in the middle cavity from the heat of the furround¬
ing air, and the water produced from it is carried off
through the pipe ST, which (huts by means of the ftop-
cock r. The whole machine is covered by a lid made
of tin, and painted wdth oil colour, to prevent ruft.
“ When this machine is employed, the middle ca¬
vity b b b b, fig. 2. and the lid GH, fig. 3* the in¬
terior cavity, the external cavity a a a a, fig. 2. and
the lid wdrich covers the whole, are all filled with pound¬
ed ice, well rammed, fo that no void fpaces remain,
and the ice of the middle cavity is allowed to drain.
The machine is then opened, and the fubftance
fubmitted to experiment being placed in the interior
cavity, it is inftantly clofed. After waiting till the
included body is completely cooled to the freezing
point, and the whole melted ice has drained from
the middle cavity, the water colle6led in the receiver
is accurately weighed. The weight of the water pro¬
duced during the experiment is an exaft meafure of
the caloric difengaged during the cooling of the in-
' eluded body, as this fubftance is evidently in a fimilar
fituation with the one formerly mentioned as included
in a hollow fphere of ice. The whole caloric difen¬
gaged from the included body is flopped by the ice in
the middle cavity, and that ice is preferved from being
affe£led by any other heat by means of the ice contain¬
ed in the cover and in the external cavity. Experi¬
ments of this kind generally laft from 15 to 20 hours,
but they are fometimes accelerated by covering up the
fubftance in the interior cavity with well drained ice,
which haftens its cooling.
“ It is abfolutely requifite that there be no com¬
munication between the external and middle cavities
of the calorimeter, otherwife the ice melted by the in¬
fluence of the furrounding air, in the external cavity,
would mix with the water produced from the ice of
the middle cavity, which would no longer be a meafure
a Taels
Bodies.
Specific
Gravity.
Specific
Caloric.
I. Gases.
Hydrogen gas
Oxygen gas
Common air
Carbonic acid gas
Steam -
Azotic gas
II. Liquids.
Water
Carbonate of ammonia
Arterial blood
Cows milk
Sulphuret of ammonia
Venous blood
Solution of brown fugar
Nitric acid
Sulphate of magnefia
Water
Common fait 1 1
Water - 8 j
Nitre 1 \
Water 8 j
Muriate of ammonia 1
Water
Tartar I 1
Water 237.33
Solution of potafs
Sulphate of iron 1
Water - 2.5
Sulphate of foda 1
Water 2.9
Oil of olives
Ammonia
a}
}-
O.QOOO94
O.OO34
0.001 22
O.OO183
0.00120
I. OOOO
1.0324
0.8l8
I.346
0-9H3
O.997
2I.4OOO
4.749O
I.79OO
I.O459
I.55OO
O.7036
I.OOOQ
I.85I
I-o30
0.9999
0.9940
0.8928
0.8600
0.844
0.844
0.832
0.8167
0.779
0.765
0-759
0-734
0.728
0.710
0.7080
Caloric.
C H E M
Table. Contiuued.
I S T R Y.
Table continued.
477
Caloric*
——. ■ ■« ■■ ii i kml
Bodies.
}
Specific
Gravity.
Muriatic acid
Sulphuric acid 4
Water - 5
Alum I 1
Water 4.45 j
Nitric acid 9t1
Lime 1 3
Nitre 1")
Water 3 3
Alcohol
Sulphuric acid
Nitrous acid
Linfeed oil
Spermaceti oil
Oil of turpentine
Vinegar
Lime qT
Water 163
Mercury
Diililled vinegar
III. Solids.
Ice
Ox-hide with the hair
Lungs of a fheep
Lean of ox-beef
Pine
Fir
Lime
Pitch-pine
Apple tree
Alder
Oak
Afh
Crab-apple
Rice
Horfe beans
Daft of the pine tree
Peafe
Beech
Hornbeam
Birch
Wheat
Elm
Female oak
Plum tree
Ebony
Barley
Oats
Pitcoal
Charcoal
Chalk
Ruft of iron
White oxide of antimony
w a Hied
Oxide of copper nearly
freed from air
Quicklime
1.122
0.8371
1.S40
i-355
0.9403
0.9910
I3-568
0.408
0.447
0.408
0.495
0.639
0.484
o-5 31
0.631
0.603
0.692
0.690
0.608
0.646
0.668
0.687
1-054
Specific
Caloric.
0.6800
O.6631
O.649
O.6181
O.646
0.6021
o. ^968
o 576
0.528
0.5000
0.472
0.3870
0-3346
0.3100
0.1030
0.9000
0.787
0.769
o 74'O
0.65
0.60
0.62
0.58
0.57
o-53
0.51
0.51
0.50
0.5050
0.5020
0.5000
0.4920
0.49
0.48
0.48
0.4770
0.47
o-45
0.44
o-43
0.4210
0.4160
0.2777
0.2631
0.2564
0.2500
0.2270
0.2272
0.2199
Bodies.
Specific.
Gravity.
Stoneware
Agate
Cryltal
Cinders
Swedilh glafs
Afhes of cinders
Sulphur
Flint glafs
Ruft of iron nearly freed
from air
White oxide of antimony
ditto
Allies of the elm
Oxide of zinc nearly free
from air
Iron
Brafs
Copper
Sheet iron
Oxide of lead and tin
Gun-metal
White oxide of tin near
ly free from air
Zinc
Allies of charcoal
Silver
Yellow oxide of lead near
ly freed from air
Tin '
Antimony
Gold
Lead
Bifmuth
2.648
3.189?
2.386
1.99
3-3293
Specific
Caloric.
7.876
8.358
8.784
7*I54
10.001.
7.380
6.107
19.040
11.456
9.861
°*195
0.195
0.1929
0.1923
0.187
0.1885
0.183
0.174
0.1666
0.1666
0.1402
0.1369
0.1264
0.1141
0.1121
o. 1099
0.102
0.1 100
0.0990
0.0981
0.0909
0.082
0.0680
0.0661
0.0637
0.050
0.0424
0-043
2. Of the absolute Quantity of Caloric.
1. Such then are the different methods which have
been propofed, to afcertain the relative quantities of ca¬
loric which are neceffary to reduce bodies to the fame
temperature. Attempts have alfo been made to dif-
cover the temperature of abfolute privation, and thus
to afcertain the whole quantity of caloric wdiich a body
contains. ... aGS
The firft attempt made with this view, was by the Dr Irvine’s
late Dr Irvine of Glafgow. The theorem which he method,
invented to afcertain the real zero, or the abfolute
quantity of caloric which a body contains^ is founded
on the uniformity of the fpecinc caloric of bodies at ^
all temperatures. And taking it f°r granted that thefouncje(j on
fpecific caloric of bodies is always the fame whatever the unitor-',
be the temperature, the whole quantity, or the abfolute mity of
quantity, will be proportional to the fpecific caloric. C2~
Having difcovered the ratio between the abfolute ca¬
lorics of bodies, and the difference between two abfo¬
lute calorics, the whole quantity in any body might be
found by calculation. But either the data on which
the theorem proceeds are wrong, or the experiments
which have been made with the view of applying it to
the
\
478
Caloric.
268
Refults
very dif¬
ferent.
* Black's
Left. v. i.
P- S°8-
269
Mr Dal¬
ton’s me¬
thod.
CHEMISTRY.
the eftimatlon of the abfolute quantity of caloric have
been very inaccurately conduced, the refults varying
fo much from each other. According to Dr Irvine’s
own experiments and calculation, the real zero with
regard to ice would be 1228° below o° ; but according
to Dr Crawford’s it is 1500°, Mr Kirwan makes it
1318° below o° in a comparifon of the fpecific caloric
of water and ice. Lavoifier and La Place fix it at
3426° below o°, from the refult of experiments on a
mixture of water and quicklime. But in other experi¬
ments by the fame philofophers, there is a great varia¬
tion in the refult. Four parts of fulphuric acid, and
three parts of water mixed together, give a refult for
the real zero equal to 7260° below o° ; and four parts
of fulphuric acid, and five of water, give it only equal
to 2598° below o°. Profeffbr Robifon, fpeaking of
the fpecific and abfolute quantities of heat in bodies
being fuppofed to be proportional, obferves that “ this
opinion is juft, only on the fuppofition that the mea-
fures, obtained by experiments and calculation, are con-
flantly the fame, whatever the temperatures may be
in which the experiments are made. Dr Irvine’s in^
genious method of difeovering the temperature of ab¬
folute privati®n, evidently prefuppofes this conftancy
of fpecific heat ; or, if they are not conftant, it fup-
pofes that we know the whole lawT of variation. Now
both of thefe affumptions are highly improbable. In
none of the progreflions of natural operations that we
are acquainted with do wre find this conftancy. It is
much more analogous to other phenomena, to fuppofe
that, in the temperatures near to that of abfolute pri¬
vation, the quantities of heat neceffary for producing
equal elevation gradually diminiih, and this, perhaps,
without end, like the diftance of the hyperbola from its
aflymptote. It is equally probable that the law of di¬
minution may be different in different fubftances. This
will caufe the meafures of fpecific heats to change their
proportions continually j and therefore the fpecific ca¬
pacities obferved in temperatures, all of which are far
removed from that of the entire abfence of heat, give
us no means of obtaining the proportions of the accu¬
mulated fum of all the heats which have been received
into the fubftances. It follows from this, that even al¬
though it Ihould be granted to Dr Irvine, that the
heat which emerges, in mixing vitriolic acid and wa¬
ter, or in the freezing of w’ater, is the difference be¬
tween the abfolute heat of the mixture, or the ice, and
the abfolute heats of the fubftances before mixture, or
of the water before freezing, ftill we cannot afeertain
thofe abfolute heats, or the temperature of no heat.
Accordingly, it appears that it has been only in a
very fewr cafes that Dr Irvine found a tolerable coin¬
cidence of his determination of this extreme cold ; and
the determination by means of mixtures differed enor-
moufly from thofe obtained by means of congelation ;
and ftill more from thofe obtained by means of the con-
denfation of vapour
2. Mr Dalton has propofed another hypothefis for
determining the real zero, or the abfolute quantity of
caloric in bodies. He obferves that the remarkable
faft of the quantity of expanfion of elaftic fluids being
the fame in the fame circumftances, (hews, that it de¬
pends folely upon heat: “ whereas the expanfion in fo-
lid and liquid bodies feems to depend upon an adjuft-
raent of the two oppofite forces of heat and chemical
affinity, the one a conjlant force in the fame tempera- Caloric,
ture, the other a variable one, according to the nature * ruii
of the body j hence the unequal expanfion of fuch
bodies. It feems therefore that general law's refpedl-
ing the abfolute quantity and the nature of heat, are
more likely to be derived from elaftic fluids than from
other fubftances.
In order to explain the manner in which elaftic
fluids expand by heat, let us affume an hypothefis that
the repulfive force of each particle is exadlly propor¬
tional to the whole quantity of heat combined wfith it,
or in other words to its temperature reckoned from the
point of total privation : then, fince the diameter of
each particle’s fphere of influence is as the cube
root of the fpace occupied by the mafs, we {hall have
3  3 
\11000 : V' 1325 (10 : 11, nearly) : : the abfolute
quantity of heat in air of 550: the abfolute quantity
in air of 212°. This gives the point of total privation
of heat, or abfolute cold, at 15470 below the point at
which water freezes. Dr Crawford deduces the faid
point by a method w’holly different to be 15320. So
near a coincidence is certainly more than fortuitous.
The only Objeftion I fee to this hypothefis is, that
it neceffarily requires the augmentation of elaftic fluids
for a given quantity of heat to be greater in the higher-
temperatures than in the lower, becaufe the cubes of a
feries of numbers in arithmetical progreffion differ
more the larger the numbers or roots : but it has juft
been ftrewm that in fa<ft an augmentation of a contrary
kind is obferved. This refers us to the confideration
whether the mercurial thermometer is an accurate
meafure of the increments of heat; if it be, the hypo¬
thefis fails ; but if equal increments of heat caufe a
greater expanfion in mercury in the higher than in
the lower temperatures, and that in a fmall degree,
the fa£t noticed above, inftead of being an obje&ion,
will corroborate the hypothefis. Dr Crawford deter¬
mines the expanfions of mercury to be very nearly in
proportion to the increments of heat: M. De Luc
makes them to be lefs for a given quantity of heat in
the low'er than in the higher part of the fcale ; and in
a ratio that agrees with this hypothefis. Now as
every other liquid wre are acquainted with is found to
expand more in the higher than in the lower tempera¬
tures } analogy is in favour of the conclufions of De
Luc, that mercury does the fame.” Manch.
The different methods wffiich have been propofed v.
by philofophers to deteimine the real zero, or the ab-602*
folute quantity of caloric in bodies, and the want of
coincidence between the refults of the experiments and
calculations, founded on thefe methods, (hew us at
leaft, that the fubjeft is attended with great difficulty
and uncertainty. Perhaps the prefent ftate of our
knowledge does not furnifti us with the means of re¬
moving the difficulty. Some fortunate difeovery is
ftill needed, to guide our fteps in the folution of this
problem. # 270
3. Having thus confidered the relative and abfo-Cold,
lute quantities of caloric in bodies, and the methods
which have been propofed for afeertaining thefe quan¬
tities, it may be neceffary to ftate in what fenle, or
with what limitations, the term co/a'is to be employed.
When we leave a room at the temperature of 6o°, and
vo into the air in a frofty day at the temperature of
I S2®*
C H E M
Caloric. ? 2e, we fay tKat it is cold j or when the hand is held
 " in water at the temperature of 100° for a few minutes,
and then fuddenly plunged into water at the tempera¬
ture of 40°, the latter is faid to_ be cold. This, how¬
ever is merely an expreflion of the fenfation excited
in the body, which depends folely on the abltraflion
of its heat. This may be proved by the following ex¬
periment. If three quantities of water are taken, the
firft at the temperature of 3 2°, the fecond at the tem¬
perature of 50°, and the third at the temperature
of 100°. Immerfe the right hand into the water
at the temperature of 100°, and the left into the
water at the temperature of 3 2°. Let them remain
for a minute, and then fuddenly plunge both hands
into the water at the intermediate temperature of 5° >
the right hand will feel cold, and the left hand warm;
and thus different fenfations are produced by the fame
body at the fame time and at the fame temperatuie.
But this depends entirely on the previous date of the
hands, and on the abforption or abdra&ion of caloric •,
' and this Teeming paradox is eafily explained by what
has been faid on the equal diftribution of caloric.
The right hand which was placed in the water at the
• temperature of ioo° abforbed caloric, becaufe the tem¬
perature of the water is above that of the body.
excites the fenfation of heat 5 but when the fame hand
is pteced in the water at the temperature of 50° it is
deprived of caloric, becaufe the furrounding medium
is far below its temperature •, and thus the fenfation oi.
cold is produced. But from the left hand, placed in
the water at 3 2° caloric is abftradled, which gives the
fenfation of cold, and the fame hand placed in the wa¬
ter at 50° receives caloric, and this entering the body,
excites the fenfation of heat. ^
Thus then, the term cold\s merely expreflive of tne
relative temperature of twyo bodies. In common lan¬
guage, the word cold is fufficiently intelligible, but m
the prefent view of the do£trine of caloric, it can have
no other precife meaning, than to exprefs the ab ence
of a quantity of heat.
Obferving the remarkable effedls which wrere. pro¬
duced on fluids by the abftradlion of caloric, it is not
at all furprifing that the phenomena which were not
obferved w’ith great accuracy, fliould be afcnbed rather
to the addition of fome new body, than to the abflrac-
„r tion of one which was formerly in combination.
Frigorific Hence originated the hypothefis which fopP?led the
particles, exiflence of the frigorific particles of e . airan an
Mufchenbroeck, which prevailed till the effeas o. ca¬
loric were developed by the difcovenes of modern che-
miflry. They were led to this hypothefis ot the en¬
trance of extraneous matter into water when it is con¬
verted from the fluid into the folid ftate, from obferv¬
ing the increafe of bulk which takes place. fhele
frferorific particles, to wdiich all the effeas of cold wete
afcnbed, it was imagined, had fome refemblance to nitre.
This opinion probably arofe from the circumftance of a
great degree of cold, or diminution of temperature, being
produced by diflblving nitre in water. 1 he fngonfic
particles were fuppofed to be conftantly floating m the
air, and by mixing with liquid bodies, as water, con¬
verted them into folids, by aaing the part of wedges,
which prevented the free motion of the particles among
each other. . ... ,,
The experiments of Profellor Piaetj in whicn coi
I S T R Y. 479
feems to be refleaed, Hill give fome fupport to this Caloric.
opinion. Twto concave mirrors of tin were placed J"*
at the diftance of io|- feet from each other j a glafs 272
vefiel full of fnow wras placed in the focus of the caHeems
one, and an air thermometer in that of the other. The ”
thermometer funk feveral degrees, but when the fnow
was removed, it rote again j and when a greater degree
of cold was produced on the fnow, by pouring an acid
upon it which diffolved it rapidly, the thermometer fell
feveral degrees lower. At firft fight it appears, that
cold has been given out by the fnow, and this cold re-
flefted by the mirrors occafioned the fall of the ther¬
mometer. The explanation of this faft is not without
difficulty. As the rays of caloric are emitted by all
furrounding bodies, the temperature of the thermometer
is probably kept up by fome of thefe rays. Sup-
pofe when the thermometer is placed in the focus Accounted
of one of the mirrors, that it ftands at the fame for.
temperature that it would do when brought into con-
taft with any other of the furrounding bodies j and
that this temperature is partly owing to the rays of
caloric which are palling off from theie bodies. il then,
there is any interruption of thefe rays, the temperature
of that body, as the thermometer, muff be diminilhed.
This is probably what takes place when the tempeia-
ture of the thermometer in the focus of one of the mir¬
rors falls, by placing a cold body in the focus of the
other. To make this a little plainer, fuppofe the tem¬
perature of the thermometer is kept up by 100 rays of
caloric j rvhen a cold body is placed in a proper fitua-
tion, as in the focus of the oppofite mirror 5 if any
number of thefe rays be abforbed by the cold body, it
muff confequently fall in temperature.
But although the explanation be not'altogether fa-
tisfa&ory, it affords no proof of the exiftence of fngo-
rific particles. Were we even to admit this hypothe¬
fis, it would not probably affift us much in the expla¬
nation. . . 274
4. Great degrees of cold are produced, by mixing To produce
together thofe fubftances which diffolve rapidly. The great cold,
reafon of this will appear by recollefting what has been
faid of the abforption of caloric when a fohd body is
converted into a fluid. Mixtures to produce artificial
cold, are generally made of the neutral falts difiolved in ^
water; of diluted acids and fome of the neutral falls,
and of fnow or pounded ice with fome cf thefe falts. 270
A great number of experiments were made upon this 1801,p. 120
fubjea by Mr Walker * ; alfo by Profeffor Lowitz off ^ *
Pcterfburgh f ; by Fourcroy and VauquehnJ ; ^^"297.
by Guyton §. The following table exhibits the rclults ^ jbid. vol.
of thefe experiments. xxix.p. 281.
• ^Ibid. 290.
Table of Freezing Mixtures.
Mixtures.
Parts.
r Muriate of ammonia 5
I. ' Nitre - - 5
16
(.Water
2.
rMuriate of ammonia
J Nitre
J Sulphate of foda
Water
Thermometer finks.
From 50° to ioc
From 50° to f
Tabu
CHEMISTRY.
.480
Caloric.
Table of Freezing Mixtures continued.
Table of Freezing Mixtures continued.
Caloric.
Mixtures.
Thermometer finks.
Parts.
J Nitrate of ammonia I
3’ ^Water - - 1
From 50° to 40
f Nitrate of ammonia 1
4. -c Carbonate of foda I
(.Water 1
From 50° to f
f Sulphate of foda 3
^Diluted nitric acid 2
From 50 to 30
C Sulphate of foda
s ) Muriate of ammonia 4
"j Nitre - - 2
(^Diluted nitric acid 4
From 50° to io°
f Sulphate of foda 6
7. < Nitrate of ammonia 5
•C Diluted nitric acid 4
From 50° to 140
8.
f Phofphate of foda
^Diluted nitric acid 4
From 50° to 120
{Phofphate of foda,
Nitrate of ammonia
Diluted nitric acid
From 50° to 210
10.
y Sulphate of foda 8
(^Muriatic acid - 5
From 50° to oc
C Sulphate of foda
Diluted fulphuric acid 4
From 50° to 3C
12.
C Snow
^Common fait
From 3 20 to o°
I3-
f Snow or pounded ice 2
"^Common fait - 1
From o° to —50
CSnow or pounded ice 1
J Common fait - 5
I^’ ) Muriate of ammonia
L and nitre
From —50 to —i8c
r Snow or pounded ice 12
15. -j Common fait - 5
(.Nitrate of ammonia 5
From —18° to —25*
16.
f Snow and diluted ni-
[ trie acid.
From o° to —46°
17-
C Potalh
Snow
From 3 20 to —51s
f Snow - - 2
;l8. < Diluted fulphuric acid 1
(.Diluted nitric acid 1
From —io° to -—56°
When any of thefe fubftances are to be employed as How to ufa
freezing mixtures, the falts fhould be ufed frelh cry-the freez-
ftallized, and reduced to fine powder ; and it will per- in£ mix“
haps be found moft convenient to obferve the proper- u L "
tions which are fet down in the table. Suppofe it is
wanted to produce a degree of artificial cold equal to
—50°, which is the temperature produced from 32°
by the 20th freezing mixture. The fubftances em¬
ployed, namely, the muriate of lime and the fnow,
muft be previoufty cooled down to the temperature of
3 2°, or any degree below it. This may be done by
placing them feparately in the nth freezing mixture,
the fulphate of foda and diluted fulphuric acid, which
reduces the temperature from 5c0 to 30 y or in the
12th freezing mixture of fnow and common fait, which
reduces the temperature from 32° to o. The mate¬
rials thus cooled down, are then to be mixed together
as quickly as poflible, when, if the experiment fuc-
ceed, the temperature will fall from 32° to —50°, as 2^6
in the 20th freezing mixture. The veffels which are Vefl'els.
employed for thefe proceffes fhould be very thin, and
made of the beft conduftors of heat. Veffels of tin
plate anfwTer the purpofe, and when acids are to be
ufed, they may be lined with wax, which will fecure
them fufficiently againft their adlion. They fhould be
of no larger dimenfions than juft to contain the ma¬
terials.
Sect. VI. Of the Sources of Caloric.
We are now to confider the means by which caloric
may be evolved, or rendered fenfible. This is a fub-
je£t of great importance, both as a curious inveftiga-
tion, and as a ufeful and neceffary application in che-
miftry and the arts of life. According to the differ¬
ent fources from which caloric is derived, or the means
which are employed for its evolution, thefe may be
reckoned five in number y namely, percuflion, fric¬
tion, mixture, the fun, combuftion: and we fhall
confider them in the order in which they have been
named.
Firft
CHE
M
Caloric.
277
Flint and
fteel.
278
Heat pro¬
duced
owing to
condenfa-
tion
279
in airs.
* Phil.
Vranf.
1789,
p. 44.
f blanch.
Mem. vol.
V- P- SlS'
280
in hard
bodies.
Firft Source of Calorlcj
PercuJJion.
The produ&ion of heat by linking together flint
and fteel, is a well know'n fa6t. The fame thing alfo
takes place when many other hard bodies are ftruck
againft each other. Fires are frequently kindled by
making a piece of iron red-hot by percuflion, wdiich
is effefted by ftriking it fmartly with a hammer. In
moft of the cafes in which caloric is evolved by per¬
cuflion, this evolution is afcribed to the condenfation
of the particles of the body ftruck. This has been
obferved to take place, both in elaftic fluids and li¬
quids.
j. The hidden condenfation of air alone, has been
found to produce a change of feveral degrees in the
thermometer. In fome experiments by Dr Darwin,
the condenfed air from an air-gun, thrown on the
bulb of a thermometer, uniformly funk it about 20.
This (hews that the condenfed air had given out fome
of its caloric ; for during the operation of condenfing
it, the apparatus became fenfibly hot *.
Mr Dalton’s experiments on the condenfation and
rarefaftion of air, (hew that an increafe of temperature
of 50° is produced, by admitting air into an exhauft-
ed receiver j and when the equilibrium is reftored to
condenfed air, 50° of cold is produced. The fudden-
nefs of the fall and rife of the thermometer is very re¬
markable in thefe cafes ; and from this circumftance,
Mr Dalton conjedlures, that the real change of tem¬
perature of the air or medium, was much greater than
the thermometer indicated ; but that the inequality ex-
ifted only for a few feconds f. From thefe experi¬
ments, therefore, it appears, that caloric is evolved
during the condenfation, and abforbed during the ra*
refaction of air.
A confiderable rife in temperature takes place, when
different gafes unite together, and are condenfed.
Muriatic acid gas and ammoniacal gas, wftien combin¬
ed together, form a folid fait j and during this combi¬
nation a great quantity of caloric is evolved.
2. To the fame caule is afcribed the caloric which
is evolved by the percuflion of hard bodies. I his is
particularly the cafe with metallic fubftances. They
acquire a confiderable increafe of denfity by hammer¬
ing ; and during this procefs caloric is evolved. A
piece of iron, it has been obferved, becomes red-hot
when it is fmartly ftruck with a hammer on an anvil j
and it acquires a confiderable increafe of denfity. Be¬
fore hammering the fpeciflc gravity of iron is 7.788 ;
after it is hammered it increaies to 7.840. In iome
other metals the increafe of denfity is ftiil more re¬
markable. Before hammering, platina is only 19.5
and after hammering, its fpecific gravity is increaied
to 23.0. As a proof that the heat is evolved by con¬
denfation, iron, which has been once heated by ham¬
mering, cannot be fubjefted to the fame procefs till t
has been again expofed to heat. It has become io
Vol. V. Part II.
I S T R Y. < 48 s
brittle that it flies to pieces under the ftrokes of the Caloric. .
hammer. ' ‘
3. It is perhaps more difficult to account for the ca* t0
loric and light which are emitted by incombuftible account for
fubftances j as, for inftance, in the cafe of two quartz incornbufti-
ftones ftruck againft each other, which has been already bles giving
alluded to in treating of light. T he particles of thefe ^e^eat .
bodies which were ftruck off by percuflion, are found, gruck.
on examination, to be in a ftate of fufion j and it would
appear that this is a cafe in which light and caloric are
emitted without oxygen having any lhare in the a£tion,
as is fuppofed to happen in all cafes of combuftion.
In fome obfervations on the appearances produced
by the collifion of fteel with hard bodies, made by Mr ^
Davy, he mentions that Mr Hawklhee Ihewed *, that
no fparks could be produced in vacuo; a faint hghtvoj ^xx;v<
was only perceived. Mr Davy thinks that the vivid p.2165.
fparks obtained from fteel in the atmofphere, are owing
to the combination of the fmail abraded and heated
metallic particles with oxygen j but it has been doubt¬
ed, he obferves, whether the faint luminous appear¬
ance, when the experiment is made in vacuo, be owing^
to the light produced by the fradlure and abrafion of
the particles of the flint, or only partly to this caule,
and partly to the ignition of the minute filaments fe-
parated from the fteel. When a fine and thin flint,
which is cafily broken, is ufed for the collifion in va¬
cuo, the light is more vivid, than when a thick one is
employed. From this he concludes that the particles
of fteel are rendered luminous in confequence of com¬
buftion. This opinion was proved by the following
experiment.
A thin piece of iron pyrites (fulphuret of iron)
was inferted in a gun-lock in place of the flint.
By collifion in the atmolphere it gave vivid fparks,
chiefly white, but fometimes mixed with a fewr red
fparks. The fame experiment was repeated when the
apparatus was introduced into the exhaufted receiver
of an air-pump but no light whatever appeared. 2g2
Mr Davy farther obferves, that bodies which be-Suppofed to
come luminous by being ftruck or rubbed together ele&ric.
vacuo, under water, or in gafes that do not contain
oxygen j fuch bodies, for inftance, as fluate and carbo¬
nate of lime, filiceous Hones, glafs, fugar, and many of
the compound falts, are both eleftrics per fe and phof-
phorefcent fubftances j fo that the flalhes they produce
are probably occafioned, partly by eleftricity and
partly by phofphorefcence. In fome cafes, however,
by the collifion of very hard, ftony bodies, which are
bad condu&ors of heat, there may be an a£tual igni¬
tion of the particles. This feems to be countenanced
by various fadls. Mr T. Wedgwood found, that a
piece of vfindow-glafs, w’hen brought into contact with
a revolving wffieel of grit, became red hot at its point
of friction, and gave off luminous particles, which were
capable of inflaming gunpowder and hydrogen gas f
and we are informed, Mr Davy adds, by a late voy-l5-4S-
ager (s), that the natives of Oonalalhka light their
fires by ftriking together twTo pieces of quartz over dry
3 ? g™*’5*
(s) Sauer’s account of this faft is the following. “ I obferved in all the huts a balket containing two large
pieces of quartz, a large piece of native fulphur, and fome dry grafs or mofs. This ferves them in kindling
fires j for which purpofe they rub the native fulphur on the Hones over the dry grais, ftrewed lightly with a
CHE M
grafs, their furfaces being prevxoufly rubbed with ful-
phur *.
Second Source of Caloric,
Friction.
I S T R Y.
to amount to 837 grs. As the weight of this duft
amounts to no more than -g^rg-th part of that of the cy¬
linder, it muft have given off 948° to raife the tem¬
perature of the cylinder 1°, and confecpiently it muft
have given out 66,360° of heat in the couife of the ex-
Catorir.
233
Combufti-
ble bodies
inflamed.
2*4
Heat by
fridtion not
owing to
diminifhed
fpecific ca¬
loric
-?,?5
proved by
Count
Rumford.
I. A great quantity of caloric is alfo given out by
friftion. ° The intenfity of the heat produced by fric¬
tion depends on many circumftances, and varies chiefly
in the ratio of the time employed and the nature and
lurface of the bodies which are rubbed together.
When the bodies rubbed are combuftible, as two
pieces of dry wood, they may be inflamed ; but when
they polfefs combuftibility in a low degree, or are al¬
together incombuflible, the temperature may be raifed
ib high as to communicate a degree of heat fufticient
to fet fire to combuftible bodies. Greater difficulty
ft ill attends the explanation of the phenomena of the
evolution of caloric by friction than by the percuffion
of hard, incombuflible bodies. In this cafe there can
be no increafe of denfity by the friftion in many in-
ftances, for caloric is evolved by rubbing together two
pieces of wood,, or by rubbing the hand on a piece of
foft cloth where increafe of denfity can fcarcely be fup-
pofed. Nor can the increafe of temperature by fric¬
tion be accounted for by the diminution of the fpecific
caloric of the bodies which are rubbed together ; for
Count Rumford, who made fome interefting experi¬
ments on this fubjeft, could not difcover any change
in this refpeff, and fuppofing that this change had
taken place, it would not be fufficiently great to ac¬
count for all the heat produced. In one of thefe ex¬
periments he took a brafs fix-pounder, caft folid, and
rough as it came from the foundery 5 fixed it horizon¬
tally on the machine fixed for boring, and caufed its
extremity to be cut off; and by turning round the
metal in that part, a folid cylinder was formed 7t *n*
ches in diameter, and 9-,% inches long. This when
finifhed remained joined to the reft of the metal by a
fmall cylindrical neck 2-f inches in diameter, and 2-^0
inches long. This fhort cylinder was bored with a
horizontal borer ufed in boring cannon. Its bore
which was 3-rg- inches in diameter, inftead of being
continued through its whole length 9i^ inches, was
only 7-1— inches in length. A folid bottom of z/g-
mches in length was thus left. A blunt fteel borer
was preiled againft the bottom of the bore of the
cylinder with a force equal to 10,000 lb. avoirdupois ;
and the cylinder was turned round by horfes at the
rate of about 32 times in a minute. To prevent the
diffipation oAhe heat, the cylinder was covered up
with thick flannel. At the beginning of the experi¬
ment the temperature of the air and of the cylinder
was 6o°. At the end of 30', when it had made 960
revolutions, a mercurial thermometer rvas introduced
into the hole made to receive it in the fide of the cy¬
linder, and the mercury rofe to 1300, ^
borer was removed, and the metallic duft or fcales
taken out of the bottom of the cylinder, it was found
periment.
2. But to determine whether the, air of the atmo-Nor to the
fphere had any part or not in the generation of thisair-
heat, by one decifive experiment, he contrived the fol¬
lowing, in which it was impoffible for it to produce
any eft'edf whatever. The apparatus was inclofed in a
wooden box, which was made water-tight, and be-
ing filled with water, completely excluded the exter¬
nal air. The quantity of water employed was 18.77 lb.
avoirdupois or 2^- wine gallons, and the temperature
at the commencement of the experiment was 6o°.
The machine was put in motion, and moved at the
fame rate as in the former experiment. At the end
of an hour the temperature was 107° in half an hour
more, it rofe to 178°, and at the end of two hours and
30' from the beginning of the experiment the. water
adfuallv boiled. By Count Rumford’s calculation the
caloric' generated by fridlion in this experiment, and
accumulated in two hours and 3''^* wTould have heated
ice-cold water 18o°, or caufed it to boil. From the
refults of his computation it appears, that the quantity
of caloric thus generated equably, ivas greater tnan that
produced equably in thecombuftion of nine wax-candles,
each I of an inch in diameter, burning with clear bright
flames for the fame length of time. 2*7
Reflecting on thefe experiments, Count Rumford
recurs to the queftion, What is heat ? Is there any concju(jes
fuch thing as an igneous fluid ? And after dating that mat heat
the quantity of caloric thus generated could neither be is motion,
furnifhed by the particles of the metal, detached from
the folid maffes, nor by the air, nor by the water, be-
caufe it muft have received its heat from the appara¬
tus, he concludes, that caloric is not a material fub-
ftance, but only a peculiar kind of motion produced
among the particles of matter f. f Pbif.
q. The experiments of Profeffor Pi&et alfo prove, TV™/:
that the caloric generated by friftion is not owing to 179s* P- 8o*
the combination of oxygen with any of the bodies.
FIs contrived an apparatus which could be introduced
into the receiver of an air-pump. By means of this ags
apparatus, a piece of adamantine fpar was rubbed Nor to
againft a fteel cup in the open air. A thermometer ^nna-
which was fixed in the infide of the cup, did not r^e0Xygenj
when the apparatus was fet in motion, although abund¬
ance of fparks were produced. When the apparatus
was placed in an exhaufted receiver, and the experi¬
ment repeated, a phofphoric light, but no fparks, ap¬
peared, nor was the thermometer any way affefted ;
but when a ftnaller brafs cup was employed j . and a
piece of brafs rubbed againft it in the open air, the
thermometer was not affe&ed till the motion ceafed,
and then it rofe O.30. The caloric, it would appear,
was carried off as it was generated, by the motion of
the air. When the fame experiment was repeated
few feathers in the top where the fulphur falls; then the, ftrike the two Hones one againft the other ; the fine
particles of fulphur immediately blaze like a Haiti of lightning, and communicating ,nth the draw fet the whole
in a flame. Sauer's Account of Billings' Expedition to the northern parts oj Kujjw, p. 159.
Caloric.
t Effai
fur le Fsu,
chap. ix.
2S9
Probably
owing to
ciedlricity.
190
Choice of
wood in
machines
important
on account
of the fric¬
tion.
CHE M
in vacuo, the thermometer rofe 1.20, and it began to rife
as foon as the fri&ion commenced. When a piece of
wood wTas made to rub on a wooden cup, the thermo¬
meter role 2.10, and in vacuo 2.40 f.
Theie experiments, therefore, are fufficiently con-
clufive to prove that the caloric evolved by friftion is
not derived from the atmofpbere ; but ftill the queftion
recurs, What is its origin ? No fatisfa&ory anfwer can
be given to this queftion, if it cannot be refolved, as
fome have fuppofed, by having recourfe to the agency
of eleftricity •, and, conftdering the fimilarity ot the
effecls of caloric and eledfricity in heating and cool¬
ing bodies, in producing the expanfion and fufion
of metallic fubftances, in effe&ing the aftual com-
buftion of inflammable matters, and that in other
refpects the one can be fubftituted for the other, it is
not at all improbable that ele£lric matter, which is ge¬
nerated in great abundance by fridtion, may be the
chief agent in the evolution of caloric by the fnftion of
bodies on each other.
4. In fome obfervations on fpontaneous inflamma¬
tions by Berthollet, he mentions the experiments
which were repeated by D. Palcani, for obtaining flic
bv the fritlion of two pieces of wood, in which he
gave to one of the rubbing pieces the form of a tablet,
and to the other that of a fpindle or cylinder j and as
the refults of fome of thefe experiments are of import¬
ance to lhew what attention ought to oe paid to the
choice of wrood, m the conftruffion of machines and
inftruments where there is confiderable fri&ion, we fhall
ftate the following.
Cylinders.
Tablet.
Boxwood,
do.
do.
do.
do.
Laurel,
do.
Ivy,
do.'
Olive,
Mulberry,
Afh,
do.
Peartree,
Cherry,
Plumtree,
Oak,
Box,
Poplar,
Oak,
Mulberry,
Laurel,
Poplar,
Ivy,
Box,
Walnut,
Olive,
Laurel,
Oak,
Fir,
Oak,
Elm,
Appletree
Fir,
Duration.
Effedt.
Senfible heat,
do.
do.
Confiderable heat!
and frtioke, j
do.
do.
do.
do.
do.
do.
Confiderable heat,
fmoke, and black-
nefs.
Senfible heat,
do.
do.
do.
do.
do.
1
•{■ Anna!, dt
Chlm- vol.
xiviii.
p. 251.
291
When the experiment was changed, and a cylinder
of one of the kinds of wood was rubbed between two
tablets of the other ; as for example, a cylinder of pop¬
lar between two tablets of mulberry wood, the in-
-creafe of the rubbed furfaces which were in contaft
with the air, produced a temperature much mote con¬
fiderable j and almoft the whole of the kinds of wood
enumerated above, took fire. _
The effeft of fri&ion alio varies according as the
I S T R Y.
woods employed of the fame kind are rubbed in the
diredlion of the fibres, or when the fibres crofs each
other. In the firft cafe the fri&ion and heat generated
are much more confiderable than in the fecond f.
Third Source of Caloric,
Mixture.
I. It is one of the chara&eriftics of chemical a&ion Change of
to produce a change of temperature. This happens in
confequence of the increafe or diminution of bulk
the bodies which have been the lubje6l of combination, tjon,
or a total change of their ftate and properties. Thus
it has been eftablifhed as a general law jn chemical
fcience, that all bodies which pafs from the lolid to the
fluid ftate, abforb a quantity of caloric : and all bodies
which pafs from the fluid to the folid ftate, give out
caloric. This law, therefore, will enable us to account
for thofe changes wThich take place by the mixture^ of
different bodies. In the courfe ot tue detail of cue
mical fcience on which we are about to enter, we ftiall
have frequent opportunities of pointing out the eflecfs
of this law. At prefent we fhall only mention a few
inftances in which caloric is evolved by mixture, or
chemicaUcf ^ fubftanCeS ;n tbe ftate of gas enter
into union, and form a folid or liquid body, caloric is ing folids
evolved. _ ^ or liquids.
a. Ammoniacal gas and muriatic acid gas, when they
are mixed together, inftantly combine, and foim a fo¬
lid fait, at the fame time giving out a quantity of caloric.
b. When oxygen gas and nitrous gas are mixed to¬
gether, they combine and form a liquid, and at the
moment of union, give out caloric.
3. When two liquids are mixed together, and if the
denfity of the mixture be greater than the mean of
the two liquids, caloric is evolved during the combi¬
nation.
a. When alcohol or fpirits of wine and water are
mixed together, the denfity is greater than the mean
of the two liquids } caloric therefore is given out dur¬
ing the mixture.
b. A much greater degree of heat is produced by
mixing together fulphuric acid and water. If four par^s
offulpburic acid be combined with one part 01 water, the
denfity of the mixture is much greater than the me¬
dium denfity of the two liquids, and accordingly the
quantity of caloric evolved is fufticient to boil water.
4. A great quantity of caloric is alfo given out
when a fluid body combines with a lolid. M e have
an inftance of this in the hacking of lime.
a. When water is thrown upon quicklime, it inflantly
difappears j for part of it combines with the lime, and
becomes folid j and thus pafling from the liquid to the
folid ftate, it gives out caloric.
b. If a quantity of fulphuric acid be poured upon
quicklime, the caloric evolved is fufficient to raife
part of the fulphuric acid into vapour. 293
5. Were we to reverfe thefe experiments, and ftate Cold pro-
inftances of caloric being abforbed during the mixture ^uced by
of bodies, we fhould obferve the operation of the fame coming
law, in the cafe of folid bodies becoming fluid, pro- fuddenly
ducing a great degree of cold. But it appears that fluid,
the produftlon of cold by the folution of falls in wa¬
ter is owing to the water which is in a previous ftate
3 P 2 of
484
CHEMISTRY.
Caloric. 0f combination with one of the falts ; and thus water
1 Y ' paffing from the folid to the liquid (late, muft abforb
caloric, and therefore produce cold. The falts which
are molt proper for this purpofe, contain a great pro¬
portion of water in their compolition j for if the fame
falts are deprived of water by expofmg them to heat,
the fame effect by no means follows. On the contrary,
when they are diffolved in water in this ftate, heat is
produced, becaufe they combine with a portion of the
water for wThich they have a ftrong affinity, and this
water palling from the liquid to the folid ftate, gives
294 out its caloric. # ......
Heatevolv- 6. A confiderable quantity of caloric is alio gene-
ed in ter- rate(] in other mixtures, in which the fermentation and
mentation, trefa&i0n of animal and vegetable fubftances takes
&C' place. During thefe proceffes the fubftances which
are held in folution enter into new combinations, and
their chemical properties are totally changed. While
* this change is going on, there is a gradual and con-
ftant evolution of caloric. _
It is an artificial heat of this kind, which is gene¬
rated by animal and vegetable matters, and on ac¬
count of its uniformity and conftancy is employed for
promoting of vegetation ; as when horfe dung and tan¬
ner’s bark are ufed in making not beds 5 or for the
hatching of eggs, a praflice which has been long in
ufe in Egypt.
Fourth Source of Caloric,
The Sun.
1. But the great fource of light and heat in the pla¬
netary fyftem is the fun. When treating of light we
mentioned a fpeculation of philofophers about the great
and conftant wafte of light, which the fun, although a bo¬
dy of immenfe magnitude, muft fuftain. Butfince the na-
t.. 2^S ture and conftitution of the fun were difcovered by Dr
iakebodv Herfchel, thefe fpeculations fall to the ground. Accord-
ing to thefe difcoveries, the fun is not, as was formerly
fuppofed, an immenfe globe of fire, in which the ma¬
terials compofing it were continually wafting by com-
buftion ; but a folid opaque body, fimilar to the other
planets, and furrounded by a very denfe atmofphere,
in which are obferved two kinds of clouds. I he lower
region of clouds is fimilar to thofe in the atmofphere
of the earth. The uppermoft region of clouds is lu¬
minous, and from this proceed the light and heat
which were fuppofed to come from the body of the
fun. This luminous region, it appears from Dr Her-
fchel’s obfervations, in confequence of changes which
fcem to be conftantly going on in it, exhibits different
degrees of fplendour, diminifhing greatly the quantity
of light and heat which are emitted at otner t.mes.
- rj'0 thefe variations he afcribes the difference of tempe¬
rature in different feafons, and the confequent abun-
> dance or deficiency of crops.
TDr.rk co- 2. It is a familiar obfervation, that dark-coloured
lours ab- clothes, as black for inftance, are much warmei than
fyib heat, thofe which are of a lighter colour. The obfervation
and the praftice founded upon it are correff, although
the reafon is only obvious to the philofopher. T he
rays of light, and alfo probably thofe of caloric, are
Caloric.
refle&ed in greater proportion by white bodies, than
by thofe which are of a deeper colour. The fun’s
rays enter the opaque body, and combine with it, and
thus increafe the temperature. Thefe rays are per¬
mitted to pafs through tranfparent bodies, which are
very little affe&ed by them; but combining with opaque
bodies they heat them, and the deeper the colour of
the body, the greater is the increafe of temperature.
3. But this has not been left to the uncertainty of 297
common obfervation. Experiments were made >by Dr Hooke and
Franklin, and before him by Dr Hooke, to afcertain this s
curious point. Pieces of cloth of different colours were m<;nts>
placed upon fnow, and expofed to the light of the fun.
The colours were white, red, blue, black j and it w’as
found that the darkeft coloured pieces acquired moft
heat, becaufe they funk deepeft in the fnow, and this
was in proportion to the darknefs of the colour. 2pg
Mr Davy made a fimilar experiment, to determine Mr Davy’s,!
the correfpondence between the increafe of repulfive
motion in bodies from the a£lion of light and dark
colours.
“ Six fimilar pieces of copper, (t) of equal weight,
fize, and denfity, were thus coloured, one white, one
yellow, one red, one green, one blue, and one black.
A portion of a mixture of oil and wax, which became
fluid at about 76°, was placed on the centre of each
on the inferior fide. They were then attached to a
board painted white, and fo placed with regard to the
fun, that their upper furfaces were equally expofed to the
light. Their inferior furfaces, to which the cerate was
attached, were equally deprived of light and heat, that
is, they were fo expofed, that there could be no mif-
take with regard to the repulfive motion generated in
them by the action of light. The changes of tempe¬
rature in them, from the aftion of light, took place in
the following order. The cerate on the black plate
began to melt perceptibly before the reft, the blue
next in order, then the green and the red, and laftly
the yellow. The white was Icarcely at all affected j
the black was in a complete ftate of fufion *. It appears, * Beddoet*
therefore, from thefe experiments, that caloric enters Ct™^lbu~
bodies in different proportions*, and in the greateft 44*
proportion in the darkeft coloured bodies. Bodies
It appears too, that tbofe bodies which abforb moft
light, acquire the greateft degree of temperature when i0rb moft
expofed to the fun’s rays. This has been demon-light be-
ftrated by the experiments of Wedgwood, Cavallo, war *
and Piftet.
The former took two pieces of phofphorefcent marble,
one of which was blackened, and placed them on a
hot iron. No light appeared from the blackened mar¬
ble, but the other exhibited its ufual phofphorefcence.
Upon a fecond expofure, the piece which was not
blackened gave a faint light *, the blackened one, as
before, gave none at all. When the black was wdped
off, and both pieces were again placed upon the heater,
no light appeared either from the one or the other.
This experiment fhows, that the phofphorefcent pro¬
perty was nearly deftroyed without any vifible light
having appeared. But both pieces of marble before
being heated, muft have contained the fame quantity
(t) Each an inch fquare, and two lines thick.
C H E M
Caloric.
\ Ibid. 17 So
P- 537-
+
Jitr U Feu,
ch. iv.
300
Different
heating
power of
the rays.
3°i
Solar rays
of three
kinds.
of light and heat, and therefore the light from the
blackened piece muft have been abforbed by the black
colour *.
In Cavallo’s experiments (u), the bulb of a ther¬
mometer was painted black, and expofed along with
other thermometers to the fun’s rays. The difterence
of temperature between the blackened thermometer
and the other, fometimes amounted to 10®; that is,
the blackened thermometer indicated a temperature
10® higher than the other. But this difference was
not conftant, for it varied according to the brightnefs
of the fun, and the denfity and temperature of the
atmofphere. Confiderable variations were alfo obferv-
ed from the difference of colours which were employ¬
ed, and from the difference of polifh of the furface 01
the plate.
The fame thing was obferved when the thermome¬
ters wrere expoied to ftrong day light. T he thermo¬
meter whole bulb was blackened indicated the higheff
temperature f.
In an experiment by Profeffor Pictet, two thermo¬
meters, one of which had its bulb blackened, when
thev were kept in a dark place, indicated the fame
temperature. Thefe experiments prove the clofe
connexion between light and caloric } for the greater
the proportion of light abforbed by anybody, the high¬
er is the temperature of that body. And when the
light is totally excluded, as in the laft-mentioned
experiment of Pi&et, the temperature is the fame %•
4. But it has been fhown that there is a very great
difference in the heating pow'er of the difteient rays
of light. It appears from the experiments of Dr
Herfchel, that this heating power increafes from the
middle of the fpearum to the red ray, and is greateft
beyond it, where the rays are invifible. Hence it is
inferred that the rays of light and caloric nearly ac¬
company each other, and that the latter are in dif¬
ferent proportions in the different coloured rays.
They are eafily feparated from each other, as when
the fun’s rays are tranfmitted through a transparent
body, the rays of light pafs on feemingly undiminifhed,
but the rays of caloric are intercepted. When the
fun’s rays are direfted to an opaque body, the rays of
light are reflefted, and the rays of caloric are abforb¬
ed and retained. T his is the cafe with the light of
the moon which, however much it be concentrated,
gives no indication of being accompanied with heat.
^ It has alfo been fhown, that the different rays of
light produce different chemical effeffs on metallic
falls and oxides. Thefe effe&s increafe on the oppo-
fite direftion of the fpeftrum, from the heating power
of the rays. From the middle of the fpeftrum towards
the violet end, they become more powerful, and pro¬
duce the greateft effeft beyond the vifible rays.^
5. From thefe difcoveries it appears, that the folar
rays are of three kinds. 1. Raysw’hich produce heat 5
2. Rays which produce colour, and 3. Rays which de¬
prive metallic fubftances of their oxygen. The firft
302
I S T R Y.
fet of rays is in greateft abundance, or are moft power¬
ful towards the red end of the fpe&rum, and are leaft
refrafted. The fecond fet, or thofe which illuminate
objedls, are moft powerful in the middle of the fpec-
trum 5 and the third fet produce the greateft effeft to¬
wards the violet end, where the rays are moft refrac-
ted# ^
6. The folar rays pafs through tranfparent bodies Tranfpa-
without increafing their temperature. Tire atmofphere, rent bodies
for inftance, receives no increafe of temperature b7
mitting the fun’s rays, till thefe rays are reflefted fromlayr ray%
other bodies, or are communicated to it by bodies
which have abforbed them. 1 his is alio proved by
the fun’s rays being tranfmitted through convex lenfes,
producing a high degree of temperature when they are
concentrated, but giving no increafe of temperaiure to
the glafs itfelf. By this method, the heat which pro¬
ceeds from the fun can be greatly increafed. Indeed,
the intenfity of temperature produced in this way
is equal to that of the hotteft furnace. This is done,
either by reflefting the fun’s rays from a concave po-
lilhed mirror, or by concentrating or collecting them
by the refractive power of convex lenfes, and directing
the rays thus concentrated, on the combuftible body.
See Burning-GLA$$.
Fifth Source of Caloric,.
Combujlion.
3°3
It was impoffible for men whofe attention was di- Effects of
rected to the phenomena of nature, long to let pafs un-^™^1"100
obferved the Angular appearances which are exhibited
in the combuftion or burning of bodies. Indeed the
changes produced on bodies by this proceis, the afto-
nilhing effects which follow, and the importance of
the procefs itfelf, could not fail to excite great inte-
reft and attention. . _ r 3°4
As combuftion is one of the principal fources or importanfr
heat, it has long occupied the attention of men in ge¬
neral, both as to the means of its improvement, and
application in the arts of life, and in the difeovery of
a theory or explanation which will account for the
phenomena. But the want of fuccefs in this branch but of dif-
of philofophical inveftigation, even at the prefent day,ficult ex-
fhews that the fubjea is attended with great diffi-Planatl0n-
culty. 306
When a piece of iron is expofed to a high tempera-Difference
ture, it becomes red hot, and when it is removed from between
the heating body, it continues for fome time to give ‘ empera_
out light and heat. But when it is fuffered to cool, itture aiKj
returns to the fame ftate in which it was before it was burning,
heated, having undergone no perceptible change.
When a piece of wood is burnt, it alfo gives out light
and heat, but during this proceis it is totally changed.
Great part is diflipated, and nothing remains but a
fmall quantity of allies.
When a piece of fulphur is expofed to a temperature
between 300° and 400°, it takes fire and burns ; gives
f ifo The hint of thefe experiments, he fays, was taken from the account of an experiment in a volume of the
Philofophical Tranfaftions, made with a thermometer whofe bulb was painted black, a^nc expo e ^
the fun. The experiment alluded to was made by Dr Watfon, bilhop of Landaff. Phtlofophical Tranjathor
1763, p. 40.
486
CHEMISTRY.
Caloric, out heat and light, and during this procefs the fulphur
has acquired new properties, dr has entered into new
combinations.
Bodies to- When a metallic fubftance, zinc, for inftance, is
tally chan- expofed to a certain temperature, it alfo undergoes a
ged by very great change, during which heat and light are
tion '11'* a^° Siven out' ^ie z‘mc changed to a light, fioc-
culent fubftance, but moft other metals are reduced to
the form of powder (x).
Now, none of thefe changes can be effe&ed without
308 the prefence of atmofpherical air, or rather without
Oxygen gast]ie prcfence 0f oxygen gas, which is one of its confti-
thi^pro"efTent Parts» ani^ that Part ^ which is neceflary for
^u’the procefs of combuftion. In all cafes where com-
buftion takes place, oxygen gas difappears or changes
its ftate ; light and heat are emitted, and the combuf-
tible body has changed its properties. Such are the
phenomena of combuftion, fo far as obfervation and
experiment have gone •, but Hill the difficulty remains,
to difcover what (hare is to be afcribed to the different
agents which are neceffarily concerned in this pro¬
cefs, in the changes which are effe&ed. It is now
univerfally agreed, that oxygen gas, or its bafe, is fix¬
ed in the coitibuftible body during the procefs of com¬
buftion, and that the caloric which is neceffary to re¬
tain the oxygen in the ftate of an elaftic fluid being
emitted during the change, is the fource of the heat
which is given out by burning bodies. But what is
the fource of the light ? Is it emitted by the oxygen
gas along with the caloric in its change from the fluid
to the folid ftate ? Or has it been a conftituent part of
the combuftible body which is feparated during com¬
buftion ? Of this, different opinions have been enter¬
tained by philofophers, and the queftion in a great
meafure ftill remains undecided. Let us now confider
the different theories which have been propofed to ac¬
count for thefe phenomena.
I. In the early dawn of chemiftry, when the Mat¬
tered faiffs were firft collected, and it began to affume
a fcientific form, attempts to explain this procefs were
foon made. Beecher was the firft; who gave any con-
fiftent form to a theory of combuftion. Before his
time, fulphur was confidered as the univerfal inflam¬
mable principle ; but he rejedted this opinion, confi-
dering fulphur as an inflammable fubftance, containing
the principle of inflammability, but not that principle
itfelf. This theory was improved and extended by
Stahl, who gave this principle the name of phlogi-
Jlon (v), from which the theory was called the phlo-
giftic, and from his own name the Stahlian theory.
This principle was fuppofed to exift in all inflammable
bodies, and to be the fame in them all. The diverfi-
ty which is obferved among them, in external appear¬
ance and other properties, is owing to the other prin¬
ciples or elements of which they are compofed, and
with which the common principle of inflammability,
or phlogifton, is combined. Inflammation or combuf¬
tion, with the feveral phenomena that attend it, is
fuppofed to depend on a gradual reparation and diffipa-
3°9 r
Source of
the light
not afeer-
fained.
Theories.
3IT
Stahlian.
tion of this principle •, and this being once feparated,
what remains of the body is no longer combuftible,
but is fimilar to other kinds of matter. 'I his principle
is repr-efented as a dry fubftance, of an earthy nature,
compofed of particles which more than all others are
difpofed to be affedled with a very fwift whirling mo¬
tion. When the particles of a body are agitated with
this motion, the body becomes hot, is ignited, or un¬
dergoes combuftion, according to its violence. The
heat and the light which are emitted during combuf¬
tion, depend upon a peculiar motion of the particles of
matter 5 phlogifton, which is fuppofed to be contained
in all combuftible fubftances, being moft: difpofed to
affume this motion *.
2. But before this time, a different theory was pro¬
pofed by Dr Hooke, who publifhed an account of it
in 1665, in a work entitled Micrographia ; and, in
the year 1676, in another work called Lampas. Ac¬
cording to this theory, the air of the atmofphere is the
univerfal folvent of all combuftibles. This folution
takes place when the temperature of the combuftible
body is fufficiently raifed, and during the violence of
its adlion the heat is emitted. This diffoiution of in¬
flammable bodies is a fubftance inherent in the air,
which is like, if not the very fame with, that which is
fixed in faltpetre. During this diffoiution of bodies,
part unites with the air and efcapes ; and part, after
being mixed with it, forms a coagulum or precipita¬
tion, fome of which being light, is carried” aw7ay,
while another part which is heavier, remains behind.
Some time after, an account of the fame theory was
publilhed by Dr Mayowq with fome additional expe¬
riments, in a work entitled De Sal-nitro et Spiritu Ni-
tro-aereo. The nitro-aerial particles, or the fpiritus
nitro-aereus of Mayow, was the fame as the univerfal
folvent of Hooke. According to Mayow7, this fpiritus
nitro-aereus confifts of minute particles, from the mo¬
tion of which it is produced, and w-hen the motion
is more rapid, not only heat, but light alfo, is ex¬
tricated. The following abftradl of the theory of Dr
Hooke, with Profeffbr Robifon’s obfervations, will not,
w7e hope, be unacceptable to our readers.
“ This theory, fo oppolite, as Dr Black obftrves,
to the theory of Stahl, is not lo recent as is generally
imagined. It was feen, in all its extent and import¬
ance, by Dr Robert Hooke, one of the gieateft ge-
niufes and moft ardent inquirers into the operations of
nature, who figured during the latter half of the 17th
century, a period full of great difeoveries.
“ Dr Hooke propofed this theory in ronfidernble
detail in his Micrographia^ publilhed in 1665 ; and in
his Lampas, publifhed in 1676 ; and he makes it an
important doftrine in his treatife on Comets, and in
many paffages of his Cutlerian Leffures. He promi-
fes to take it into ferious confideration, and to publilh
a full exhibition of it. The allufions made to it in his
le&ures make it evident that he had continued to make
fome defultory additions to his firft conceptions. His
Lampas contains a moft accurate explanation of flame,
which
Caloric.
* Black's
Left. vol. f
p. 231, 233.
312
Hooke’s
3T3
and May=-
ovv’s.
71514 ,
AbftraA of
Hooke’s
theory.
(x) To thefe fubftances was formerly given the name of calx or calces, but in the prefent chemical nomen¬
clature they are denominated oxides.
(y) This principle was alfo called terra fecunda or terra inflammabilis.
CHEMIST
Caloric, which cannot be furpalTed by any performance of the
prefent day.
“ In the Micrographia he ftates the theory in the
following words :
“ i. The air in which we live, and breathe, and
move, and which encompaffes and cherifhes all bodies,
is the univerfal folvent of all fulphurous (fynonymous,
at that time, with inflammable) bodies.
“ 2. This aftion it performs not till the body be
fufficiently heated, as we obferve in other folutions.
“ 3. This aBion of dijfolution produces the great heat
which we call fire.
“ 4. It a£ls with fuch violence as to agitate the par¬
ticles of the diaphanous body air, and to produce that
elaftic pulfe called light.
“ 5. This aftion, or diffolution of inflammable bo¬
dies, is performed by a fuhfiance inherent in, and mix¬
ed with the air, that is like, if not the very fame, with
that which is fixed in faltpetre.
“ 6. In this diffolution of bodies by the air, a part
of the body, uniting with the air, is diffolved or turn¬
ed into air, and efcapes and flies about.
“ 7. As one part is thus turned into air, fo another
is mixed with it, but forms a coagulum, or precipita¬
tion, fome of which is fo light as to be carried away
with the air, while other grofler and heavier matters
remain behind, &c. Sec. This latter article is fre-
quently employed in other parts of his writings, and
is fometimes called a groffer compound, mixed with
matters terrene, and originally infoluble in air, and
incombuftible.
“ Can any thing more be wanting to prove that this
is the fame with the modern theory of combuftion ?
Nothing but to (hew that this coagulum contained the
air which had formed it, by (hewing an increafe of
its weight, or by feparating it again. But tne eager
mind of Hooke, attrafted by every appearance of no¬
velty, was fatisfied with the general notion of a great
fubjeft, and immediately quitted it in chafe or lonm
other interefting object. Had he not been thus led off
by a new purfuit, this wonderful man would not only
have anticipated, but completed many of the great
tiilcovenes of the laft century. It was a doiu concep¬
tion, and only a vigorous mind could entertain it for
a moment, that the vaft heat of combuftion was con¬
tained in a few grains of air. Yet this w7as his opi¬
nion, as appears by the explanation which he gives, in
various meetings of the Royal Society, and in his lec¬
tures on comets, of the deflagration oi combuftible bo¬
dies with faltpetre, and of fiary motion.
“ In the treatife called Lampas, he obferves that
this his treatife, publiftred eleven years betore, had
been very favourably received, and that he had not
feen any valid objeftion offered to it. It was in this
interval that Dr Mayow, at Oxford, publifhed his
book De Sal-Nitro, et Spiritu Nitro-aereo, xn which
he holds precifely the fame doilrxne } but his exhioi-
tion of it is obfcure, complicated, and wavering, mix¬
ed with much mechanical nonfenfe, of wedges, and
darts, and motions, &c. according to the faihion of
the times. Hooke’s conception of the fubjeft, on the
contrary, is clear, fimple, and fteady. I he only ad¬
dition made by Mayow are fome obfervations on the
increafe of weight obferved in the preparation of dia¬
phoretic antimony, &c, Hooke, explaining at a
407
Caloric.
315
R Y.
meeting of the Royal Society, fome tricks of the plum¬
bers workmen, who called the litharge which formed
on the furface of melted lead drofs, and took it with
them as their perquifite, fays exprefsly, that they can
make drofs of the whole, and that it is more than the
lead by all the air wrhich was its menftruum. But
Mayow wrote on the fubjecl exprefsly, and it appears
in the title of his book. He is remembered, while
Hooke is forgotten, becaufe no one would think of
looking into the Micrographia for chemical informa¬
tion. The theory comes in by chance, to explain the
indeftrudlibility of charcoal in clofe veflels by heat.
Mayow alfo made many very ingenious experiments
on the air w’hich had contributed to inflammation, and
has anticipated both the manipulations and the difco-
veries of modern pneumatic chemiftry.”
3. But in the pi-ogrefs of chemical fcience, the ex-™
iffence of the imaginary principle of phlogillon began
to be called in queftion. It had been obferved, and was
proved by experiment, that fubftances became inflam¬
mable by merely being expofed to the light of the fun,
and in this way having acquired the principle of inflam¬
mability, it wasfuppoled to be the fame as light. I his
opinion of phlogifton being light fixed in bodies,
which was the firft improvement or modification of the
theory of Stahl, was adopted by Macquer and other
chemifts. 3I(^
4. In the progrefs of difeovery, this theory was ftillFarther
farther modified. The introduftion of pneumatic che-mcdlfieu>
miftry, and the accuracy and precifion which it gave
to the experiments and refearches of chemifts, enabled
them to afeertain, wdth greater certainty, the changes
w'hich take place on bodies after being fubjecled to
combuftion, as w7ell as on the air in which they are ^ry
burnt. Some of thefe changes were obferved by Dr Changes
Prieilley, whofe indefatigable labours contributed ef-obferved on
fentially to the extenfion of chemical fcience. He prje^jey^
found by experiment, that the air in which combufti-
bles had been burnt, was afterwards unfit for the fup-
port of flame, and equally fo for the breathing or ani¬
mals. He aferibed this change which the air had fuf-
fered to its combination with the phlogifton which had
feparated from the burning body during the procels of 31S
combuftion. He confidered air as neceffary to com-fuppofed
bullion, becaufe, having a ftrong affinity for phlo-^.tcom-
gifton, it attrafted it during the procefs, and combin-phlogifton.
ed with it j and by this combination the air was con¬
taminated and rendered unfit for farther combuftion,
or for animal refpiration. But ftill the difficulty re¬
mained to account for the heat and light which are ex¬
tricated during this procefs. 2>l9
According to Dr Crawford, the caloric and lightgloric^and
which appear during combuftion, exift in the air in ^ air.
which the body is burnt, and during the procefs tne
phlogifton combines with the air, from which at the
fame time the light and caloric are feparated. 320
5. Soon after Mr Kirwan propofed another opinion,Phlogiftorv
which was pretty generally adopted by chemical phi-^
lofophers. According to this opinion, hydrogen audj^^'
phlogifton are the fame } that it exifts as a conftituent
part in all combuftibles, feparating from them during
combuftion, and combining with the oxygen oi the air.
6. In the year 1777, Scheele publifhed a work 321^
which was entitled, Chemical Experiments on Air ^. j^p^heOs,
Eire. Heat according to him, ccnfifts of a certain
quantity
488
Caloric.
322
Difcovery
ofLavoifier
3*3
His theory
324
Accounts
only for
fome of the
phenomena.
C H E M I
quantity of oxygen united with phlogifton. Radiant
heat, which moves in ftraight lines, is compofed of
oxygen combined with a greater proportion of phlo¬
gifton ; and light, of oxygen combined with a ftill
greater quantity.
7. But the labours and difcoveries of the French
chemifts gave a new turn to chemical fcience. The
unfortunate Lavoifier, who had devoted his time and
his fortune to chemical purfuits, had long dire&ed his
attention to the phenomena of combuftion ^ and after
an extenfive feries of experiments, diftinguifhed. for
their accuracy and precifton, he eftablilhed the general
law, that oxygen combines with the burning body in
all cafes of combuftion-, and thus, he was enabled fatis-
faftorily to account for the phenomena of combuftion
without phlogifton, the exiftence of which had never
been proved.
8. The principles of this theory are the following.
No combuftion can take place without the prefence of
oxygen, for it is the combination of the combuftible
body with oxygen. The oxygen of the atmofphere,
which is in the ft ate of an elaftic fluid, exifts in combi¬
nation with caloric and light ; and during the combuf¬
tion, that is, the combination of the oxygen with the
combuftible body, the caloric and light are feparated.
9. This theory accounts for the phenomena of com¬
buftion in the more limited acceptation of this term,
which is merely the combination of oxygen with a
combuftible body, without any extrication of caloric
and light. Thus, oxygen combines with fome metal¬
lic fubftances and other bodies, without any percepti¬
ble emiffion of light or heat. This is called oxidation,
and the produfl of this combination is denominated an
oxide. In all cafes of combuftion oxygen combines
with the combuftible body. Indeed this is fo efiential-
ly neceffary, that no combuftion can take place with¬
out it; but in the more extenfive fignification of the
term combuftion, it is underftood, not merely to mean
the combination of oxygen with the combuftible body,
but alfo to be accompanied with the extrication of heat
and light. According to the theory of Lavoifier, the
caloric and light which appear during combuftion, are
given out by the oxygen gas. It is the feparation of
that quantity of caloric which is neceffary to retain the
bafe of this gas, or oxygen, in the form of an elaftic
fluid. When, therefore, the temperature of a body is
fufficiently raifed, the affinity between oxygen and this
body becomes greater than that which exifts between
the oxygen, and the caloric and light. The oxygen
therefore combines with the combuftible body, and the
caloric and light are feparated.
This theory is applicable to the explanation of the
phenomena of combuftion, in the more limited mean¬
ing of that term ; and it is partially applicable to
explain the phenomena in its more extenfive mean¬
ing. But when it is confidered, that the procefs
of combuftion goes on between two folids, one of
which contains oxygen in its combination, as for in-
ftance, fulphur and nitre, difficulties arife in account¬
ing for the heat and light, when the oxygen which
combines with the combuftible body, is in the folid
ftate.
To remove thefe difficulties, and to explain the ap¬
pearances, the theory of Lavoifier has been greatly
modified, or new theories propofed.
s T R Y.
10. With this view a theory has been propofed by C;.!&nc. ^
Brugnatelli. This theory fuppofes that oxygen exifts
in combination with bodies, in two dates. In the one Y}ieoryof
it is entirely deprived of its caloric and light, and in Brugnatelli
the other, it retains great part of the caloric and light,
even in its combined, concrete ftate. It is Amply call¬
ed oxygen in the firft cafe, when it is deprived of its
caloric and light; in the latter it is denominated therm*,
oxygen, when the caloric and light are combined
with it in the concrete ftate. Thermoxygen, then, is
a compound of oxygen and caloric in the concrete
ftate. This caloric is different from that which holds
the thermoxygen in the ftate of gas, and it is in the
fame relation to thermoxygen gas,, as water is to cry-
ftallized falts. This thermoxygen only enters into
the compofition of acidt, wdien it is deprived of its con¬
crete caloric. But it combines with the metals in the
ftate of thermoxygen ; that is, united with the con¬
crete part of caloric. Metallic fubftances, therefore,
are denominated thermoxides.
In its union w-ith metals, thermoxygen is either pre-
vioufly formed, or is in its nafeent ftate, during the
combination. In the latter cale, the caloric which is
difengaged by the chemical action, or that which is
applied to affift the combination, furnifhes the necef*
fary portion for the formation of the thermoxide ; that
is, the combination of oxygen containing caloric in its
concrete ftate, with a metal. I hus it is, that fome
metals require the application of heat for their folution
in concentrated acids.
The bafe of pure air is in the ftate of thermoxygen,
in its combination with water. I he metals, therefore,
which have a ftronger affinity for it than for hydrogen,
the other component part of water, readily combine
with it, without the aid of external heat, in acids di¬
luted with this fluid. Gafeous thermoxygen always
gives out caloric, when it paffes from the elaftic to the
concrete ftate ; but as thermoxygen requires little ca¬
loric for its expanfion, little is leparated when it is
condenfed. We ffiall only add the author’s explana¬
tion of the difference between atmolpherical air and
thofe fubftances which have the fame conftituent parts
in different proportion. The difference betw-een at-
mofpherical air and nitrous gas, he fuppofes, is aferibed
to the proportion of the conftituent principles, and
confequently, according to this hypothefis, the atmo-
fpherical air might be converted into nitrous gas, by
augmenting the proportion of oxygen gas, or by
diminiihing that of the azotic gas. But the difference
between thefe two gafes, according to the theory of
Brugnatelli, confifts in this, that in atmofpherical air the
azotic gas is combined with thermoxygen gas ; but in
nitrous gas, the azotic gas is combined with fimple
oxygen * Antial. dt
XX. This theory, notwithftanding its ingenuity, is Chim. vol.
regarded by fome merely as a plaufible hypothefis, xxix.p. 182.
which is little fupported by fafts. We ffiall therefore T^lxy
leave it to the confideration of our readers, and pro-which fup-
ceed to ftate the principles of another, which is pro- pofes the
pofed to be fubftituted in place of the Lavoifierian the- Jjght.^
ory, in explaining the phenomena of combuftion. In tj,e
this theory, it is fuppofed that the oxygen gas which is combutti-
abforbed during combuftion, furniffies the caloric, ble.
while the combuftible body gives out the light which
previoufly exifted in it as a component part. In proof
Caloric.
327
Lighl to¬
ri imed by
the com-
kuftible.
328
A theory
muft ex¬
plain all
the pheno¬
mena.
329
■New body
generated
by combuf-
tion.
330
Acquires an
increafe of
weight.
C H E , M
of this theory it is ftated, that fome bodies give out,
during combuftion, a greater quantity of light than
others, even where the quantity of oxygen abforbed is
kfr • that the colour of this light varies according to
the nature of the corabuftible $ and that vegetables
which grow in the dark contain no combuftible mat¬
ter, being deprived of the light which is effentially ne-
cefiary for its formation. This theory, which Gren
calls the theory of fire and co?nbuJhony is diftinftly de¬
tailed by him in the following words.
“ I take here the word fire in the ufual fenfe of com¬
mon language, and underiland by it that light which
is combined with free caloric. Combufiion is the ex¬
trication of fire with and by the decompofition of oxy¬
gen gas. Take the example of phofphorus. On its
combuftion two new produ&s, the phofphotic acid and
fire, arife from phofphorus and oxygen gas.
“ In order that the theory of combuftion be admif-
fible, it muft explain every circumftance by which this
phenomenon is accompanied, and be in contradi£Hon
with none of them. It, befides, muft not be incon-
fiftent with any other fixed invariable law of nature.
“ According to the antfihlogifiic fy/iern, a combufti-
ble body is fuch as is poffeffed of the power of attrac¬
ting, in a certain temperature, the oxygen of vital air
more ftrongly than it is attrafted by the caloric. Be¬
fides, in that fyftem, oxygen gas does not merely con-
fift of oxygen and caloric, but it likewife contains light,
in a fixed ftate, as a conftituent part.
“ If, therefore, phofphorus, at the temperature re-
quifite to its inflammation, be brought into oxygen
gas, it robs the latter of its oxygen, and makes with
it phofphonc acid \ whilft the caloric and the balls,
or matter of light, previoufly latent in the gas, are re-
ftored to liberty *, and, combining together, produce
the fire which flies off. Thus the oxygen gas is de-
compofed.
“ A new body, the phofphoric acid, is now gene¬
rated ^ and, becaufe in many cafes an acid is produ¬
ced by the combuftion of inflammable matters, this cir¬
cumftance has induced modern chemifts to denote
the bafis of vital air by the words acidifying princi¬
ple, or oxygen ; not on the ground that it is fuppofed
to be four of itfelf, but becaufe it forms an acid
only w’hen combined with an acidifiable bafis, as in
our experiment with phofphorus. And it is on this
account that, in this fyftem, combuftion has likewife
received the name of oxygenation. But in the cafe
{very often occurring) w'here the combuftible matter
imbibes oxygen, yet without becoming thereby an
acid, the product is called oxyd (alfo denominated
half-acidand the procefs is termed oxydation.
“ Since the combuftible iubftance takes up the pon¬
derable bafis of oxygen gas, and fince, according to
this fyftem, both the caloric and light are imponde¬
rable, it is thereby accounted for, why the refidue of
burnt matters, the phofphoric acid, for inftance, ac¬
quires an increafe of weight equal to that portion of
vital air which was decompofed.—If the inflammaole
fubftance be faturated with oxygen, it is rendered in-
Vol. V. Part II.
33i
I S T R Y.
capable of decompofing more oxygen gas, and the com¬
buftion is ended.
“ When the combuftion is performed in atmofpheric
air, it is then the azotic, either mingled or mixed with
the oxygen gas, that prevents thele phenomena from
going on with the fame vivacity as in pure oxygen
gas j and likewife, as the azotic gas is not affe&ed^or
afted on by the inflammable body, it is left as the refi¬
due of the atmofpheric air.
“ Hence, by that fyftem, the combuftion of phof- Combuftio*
phorus in oxygen gas is effefted by a limple affinity,
and the principle of fire is not in the combuftible body, njty ;n tjic
but in the oxygen gas. old theory.
“ However, from what I have ftated of the compo- 33?
fition of light, I cannot help thinking, that in combuf-gained
tion a double affinity takes place *, and to explain this affinity.
theory I ihall feleft the example of phofphorus. That
fubftance confifts of the bafis of light, called by me
pblogiflon, and making a conftituent part of all com-
buftible bodies united to a peculiar body, the phofipho.
ric-radical.—Oxygen gas is a compound of oxygen and
caloric. _ .
“ Nowt, when phofphorus is heated in this gas, and
by this means the force of attraftion betvi een tue
phlogifton and the phofphoric-radical is fufficiently
weakened, fo that the attraftive power between the
radical of phofphorus and the oxygen may prevail,
then the a£I of combuftion enfues. The phofpaoric
bafis attra&s the oxygen, while the phlogifton of the
phofphorus is attrafted by the caloric of the oxygen
gas. Thus, by virtue of this double affinity, two new
compounds, the phofphoric acid and fire, aiife from
the two former combinations, phofphorus and oxygen
gas. ^ j • 1
« When the radical of phofphorus, and in general
of any combuftible body, has abforbed fo much oxy¬
gen, that it is faturated wfith it, the combuftion is ar¬
rived at its higheft degree j and in the fame manner it
is ended, at the moment when all the quantity of oxy¬
gen gas, capable of being decompofed, is exhaufted.
By this it is explained, why, in a given volume of oxy¬
gen gas, only a certain quantity of pholphorus, and in
general of every other combuftible matter, can be con-
fumed by fire. r , ,
“ The increafe of weight in the refidue ol the burnt
fubftance is, in this phlogiftic, or rather eclectic fiyflern,
likewife explained by the accefs of oxygen *, and the
caloric and bafis of light are likewife fuppofed to be both
imponderable. The remaining azotic gas, not being
a fled upon by the combuftible matter, is merely the
refidue of the atmofpheric air. T- ■
“ Thofe that wiffi to be impartial, muft allow that ^gH.gjven
the light, in the antiphlogijhc fyftem, a£ls a pait out 0Xygen,
fupeffluous j that it may be thoroughly fet afide with¬
out impairing the fyftem *, that by tins fyftem thofe
phenomena cannot be explained, where light iflues from
combuftible bodies without any accefs of vital air,
(fome inftances ftf which will hereafter be given (z) j
that the influence of light upon the growth and thriv¬
ing of plants, upon the changes of their mixture dur-
8 3 Q~ ln&
(z) As in the cafe of the combination of fulphur and iron or copper.
490
Caloric.
* Grin s
Chemijlry,
335
Ignition.
C H E M I
ing vegetation, and upon the alteration in the mixture
of many other bodies, is by far too great, to allow
oxygen gas to be confidered as its only refervoir. Fi¬
nally, it muft be granted (an important point) that
the antiphlogiftic fyftem does in no way explain the
incidents preliminary to the procefs of combuftion j
and that it affords no argument to fhow why a certain
decree of heat is neceffary, in order that the combufti-
ble body be inflamed
_ ii. Such then are the general fa&s with regard to
vol. i.p.135. c0mbUftion, and fuch are the theories which have been
334 propofed, to account for the phenomena exhibited in
Three mo- this procefs. Three dates or modifications have been
difications. diftinguifhed in the aft of combuflion, namely, igni¬
tion, inflammation, and detonation.
a. Ignition, properly fpeaking, is rather a prelimi¬
nary flep, than a part of the procefs of combuftion it-
felf. A metallic fubftance, for inftance, may become
red hot when expofed to a certain temperature j but
when it is cooled, it returns without change to its for¬
mer ftate. In this cafe caloric and light are given out,
but the body undergoes no farther change. There is
no abforption of oxygen, which is one of the ordinary
phenomena of combuftion. But, with an increafe of
temperature, this alfo is effefted, and the whole phe¬
nomena of combuftion are exhibited j namely, the union
of oxygen with the combuftible body, and the emif-
fion of light and heat.
i. The fecond ftate or modification of combuftion is
called injlanmiation. This depends on the nature of
the combuftible body, owing partly to its ftrong affi¬
nity for oxygen, and partly to the flight affinity which
exifts between the particles of the combuftible body.
We have examples of this in the burning of fulphur
or phofphorus, or a candle in the open air, or in oxy¬
gen gas.
c. Detonation is another modification of combuftion.
It is a rapid and inftantaneous inflammation, accompa¬
nied with explofion. This arifes from the hidden for¬
mation of a vacuum, by the change of elaftic fluids
into the liquid ftate, or by the fudden evolution of ela •
ftic fluids from the folid ftate. Of the firft we have
an inftance in the compofition of water by the inflam¬
mation of oxygen and hydrogen gafes, which is at¬
tended with a violent explofion, great condenfation,
and the extrication of light and heat. Of the evolu¬
tion of elaftic fluids from folid bodies, we have a good
inftance in common gunpowder, from which an im-
menfe volume of elaftic vapour is inftantaneoufly extri¬
cated, w’hich, by its expanfive force being fuddenly
exerted, produces the explofion, and the irrefiftible ef-
fe&s of this powerful agent.
12. All inflammable fubftances, Dr Black obferves,
are changed, during combuftion, into one or more
stances con-prjncjp|es> p'rain t\ie combuftion of fome fubftances,
-Sr 1 ° as h-dphur and phofphorus, an acid is obtained. From
' 339 the combuftion of others, as hydrogen with oxygen,
or water, water is the product; and in the cafe of metals, they
33^
Inflamma¬
tion.
337 .
Detonation.
33s .
Combufti-
ble Cub-
S T R Y.
are reduced to the ftate of oxide, or catx^ as it was Oxygen, *
formerly called. After the combuftible fubftance has
been fubjefted to the procefs of combuftion, it is to- or
tally changed in its properties, and it can no longer
exhibit the phenomena of combuftion.
Such then are the general properties and effe£Is of
light and heat, two of the moft powerful agents, and
of the moft extenfive influence, in all the changes and
combinations which take place among bodies, by che¬
mical aftion. In many properties they referable each
other, but are totally different from all other kinds of
matter. Thefe bodies, poffeffed of a repulfive power
among the particles of each other, are attrafted by
other bodies, and combine with them j and thefe
combinations produce the moft aftonilhing effedls, giv¬
ing new forms to matter, and inducing innumerable
changes, which may be confidered as conftituting the
principle and effence of fome of the moft fublime ope¬
rations of nature, and many of the moft important pro-
ceffes of art.
Conne&ed with light and heat in many of their ob¬
vious properties, and alfo in many of the changes
which they produce upon bodies, are eleftricity and
galvanifm ; and with electricity at leaft, if not alfo
with galvanifm, the magnetic pow’er poffeffes fome
common properties } and efpecially if fome of thefe
are to be confidered, as fome have fuppofed, only as
modifications of the fame fubftances which we have
treated of, the difcuflion of thefe fubjeCts would be
properly introduced here ; but, according to the na¬
ture and arrangement of this work, each will be fully
detailed under its proper head. See Electricity,
Galvanism, Magnetism.
Chap. IV. Of OXYGEN, and OXYGEN GAS.
1. Oxygen gas, or its bafe, oxygen, is one of the of great
moft important agents in the chemical phenomena of importance,
nature, or in the proceffes of art. There is indeed
fcarcely a fingle procefs in which this fubftance has
not fome (hare. Its nature and properties, therefore,
ought to be early known. 343
Oxygen gas is one of the difcoveries of modern che- A difcovery
miftry. It was difcovered by Dr Prieftley in the >ear
1774, and from him it received the name of dephlogif-c ,e
ticated air. It was afterwards denominated highly re-
fpirable air. From Scheele, who difcovered it in
I’l'jg, it received the name of etapyreal air. It was
called vital air by Condorcet ; and Lavoifier gave it
the name of oxygen gas, by which it has fince been
generally diftinguiftied. . 343
2. Oxygen gas is moft ealily obtained by the follow-pr0cefles
ing procefs : a. Take a quantity of the fubftance cal-for obtain-
led manganefe; introduce it into the iron bottle A, inSlt*
fig. 3. to the neck of which apply the bent tube B,
which is made to fit it exaftly, and lute them together at
the joining CD (a). The bottle thus prepared, is to be
exnoled
(a) The lute which anfwers this purpofe fufficiently well, is compofed of pipe clay and Imfeed oil well beat-
en together, and reduced to the confiftence of glaziers putty. This is neatly applied to the joining, and it al¬
lowed5 to remain for eight or ten hours before it-is expofed to the heat, it will afterwards bear the higheft tem¬
perature.
C H E M I S T R
espofed to the heat of a furnace, or to that of an open
£re< A.s foon as the heat is applied, the atmofpheric
air within the bottle is driven off > and, as the bottle
becomes red hot, the quantity of air which paffes over,
is greatly increafed. Let the end of the tube con-
nedled with the bottle be introduced under the ftielf in
the pneumatic trough, and the bubbles of air will pafs
through the water, and may be received in jars filled
with water, and inverted over the opening in thelhelf.
b. Oxygen gas may alfo be obtained by treating
what is called in chemiftry the red oxide of mercury,
in a fimilar manner.
c. This gas may be alfo readily procured byint re¬
ducing into a glafs retort, a quantity of the fame fub-
ftance (manganefe) reduced to powder, adding an
equal weight of fulphuric acid, and applying a mo*
derate heat.
d. Or it may be obtained from the fubftance called
nitre or faltpetre, expofed to a red heat, in an earthen
or coated glafs retort.
Nat«?r4e of 3* In all thefc methods of obtaining this gas, it is un-
"the procefs neceffary to mention, that it muff be received in the
explained, pneumatic apparatus, in the fame way as has been di-
re£led for procuring it from the manganefe, expofed to
heat in the iron veffel J and in whatever way it is ob¬
tained, the chemical change which takes place in thefe
proceffes, is thus explained. Oxygen gas confifts of
two ingredients, the one, which is called its bafe, and
the other caloric, or the matter of heat. In the man¬
ganefe, this bafe is fuppofed to be combined with the
metallic fubftance ; and when this fubftance is expofed
to a fufficient temperature, the oxygen, having a great¬
er attraction for caloric than for the metal, combines
with it, and paffes off in the ftate of gas. The fame
change takes place, when the procefs for obtaining the
gas, by means of the red oxide of mercury, is employ¬
ed. When the fulphuric acid, which is in the ftate of
liquid, is added to the manganefe, it combines with
it, and becomes folid. But no liquid fubftance can
become folid, without being deprived^ of the caloric
neceffary to retain it in the ftate of fluidity. The ca¬
loric which retained the fulphuric acid in the liquid
ftate, combines with the oxygen of the manganefe, aff
fumes the fluid or gafeous form, and makes its efcape.
This is an example of double affinity. 1 he fulphuric
acid unites with the manganefe, and forms a folid j w’hile
the caloric combines with the bafe of oxygen, and ap-
pears in the form of oxygen gas.
Properties. 4* Oxygen gas thus obtained, poffeffes many of the
properties of common air. It is colourleis, inviiibie,
elaftic, and may be indefinitely expanded or compreffed.
Oxygen gas poffeffes neither tafte nor fmell ; its fpe-
cific gravity, according to Mr kirwan, is to that of
water as 0.00135 to i.ooco. Being therefore 740
times lighter than its bulk of water, its weight to at-
mofpherical air is in the proportion of 1103 to 1000 ;
or 100 cubic inches of oxygen gas weigh 34 grs.
while the fame meafure of atmofpherical air weighs on¬
ly 2 i grs. the temperature being 6o°, and the baro¬
meter being at 30 inches. According to Mr Davy’s
experiments, 100 cubic inches of oxygen gas weigh
35.05 grs.
Water does not fenfibly abforb oxygen gas. But
by means of ftrong preffure, it may be made to combine
with, and to retain in folution, half its bulk of the gas.
f. 491
The water thus impregnated, is not fenfibly different, Oxygen. ^
from common water in tafte or fmell, but it is faid to
have proved an ufeful remedy in fome difeafes. 346
Combuftible fubftances burn with greater brilliancy Combuftion
and rapidity in oxygen gas than in common air. In_ more.bnl-
deed it is owing to a certain quantity ol the tormer, gpn
that the procefs of combuftion goes on in the latter •,
and when the oxygen gas is exhaufted, the procefs is
interrupted. If a jar or phial is filled with this gas,
and a lighted candle introduced into it, it burns with
greater fplendour, and produces a greater degree of
heat, than in a fimilar veflel filled with common air.
If the candle be blown out, and while the fnuff is red
hot, it is introduced into a veffel filled with oxygen
gas, it re-kindles with a flight explofion, and burns
with the fame fplendour. A candle in a veffel filled
oxygen gas burns much longer than in the fame quan¬
tity of atmofpherical air. . k 34-*
Oxygen gas is effentially neceffary for refpiration. ko Animals
breathing animal can live in any air wrhich does not live a long-
contain fome proportion of oxygen gas. And the ex- '■ime m
periments of Dr Prieftley and others prove, that ani¬
mals live a much longer time in oxygen gas than in an
equal bulk of atmofpherical air. The experiments of
Count Morozzo fully eftablifh this fa£l. Into a veffel
filled with common air, and inverted over w7ater, he in¬
troduced a number of fparrows, and obferved the
effefls. The following are the refults of his expeti-
ments :
H. M.
The firft fparrow lived 3 0
The fecond - * 0 3
The third - -01
The experiments were repeated by filling the fame
veffel with oxygen gas, and he obtained the following
refults 1
H. M.
5 23
2 ro
1 30
1 10
o 30
o 47
o 27
o 30
O 22
O 21
The firft fparrow lived
The fecond
The third
The fourth - *
The fifth
The fixth
The feventh
The eighth
The ninth
The tenth
Two fparrows wTere then put in together} the one
lived for an hour, but the other died in about 20
minutes. .348
5. Oxygen Combines with a great number of bo-Oxygen
dies, and' forms compounds with them. _ It is always combines
prefented to us in a ftate of combination. In exa~(}|eSk
mining its properties, it is always as a compound ; and
thefe properties are only cognizable to our fenies in
that ftate.
When oxygen combines with metallic fubftances,
they acquire new properties, and this combination in
chemical language is denominated an oxide. Com¬
bined with many other fubftances, the nature of. the
fubftance is alfo changed, and the compound exhibits
new properties. One of the moft remarkable of thefe
is the tafte of the compound fubftance, which is often
four or acid } and becaufe this circumftance was ob¬
ferved to be one of the moft frequent and moft re-
^ markable
349
Origin of
the name.
492 C H E M
Azotic Gas. markable which attend its combinations, the name of
' oxygen, or acidifying, was invented by Lavoifier.
Oxygen gas is alfo neceffary for the germination of
the feeds of plants j but as the procefs of vegetation
advances, it is given out in great abundance by the
leaves during the day. By this means the great wafte
of oxygen gas in the proceffes of combuftion and re-
fpiration is fully repaired, and the balance between its
confumption and fupply is preferved.
6. The following is the order of its affinity for the
fubflances with which it enters into combination.
Oxygen.
Charcoal,
Titanium,
Manganefe,
Zinc,
Iron,
Tin,
Uranium,
Molybdena,
Tungflen,
Cobalt,
Antimony,
Hydrogen,
Phofphorus,
Sulphur,
Azote,
Nickel,
Arfenic,
Chromium,
Bifmuth,
Lead,
Copper,
Tellurium,
Platina,
Mercury,
Silver,
Oxide of arfenic,
Nitrous gas,
Gold,
Muriatic acid.
White oxide of manganefe,
White oxide of lead.
Chap. V. Of AZOTIC GAS.
350
Difcovery. I. Azotic gas was examined by Mr Scheele, the cele¬
brated Swedifh chemift, in 1776 j and his experiments
proved, that it is a fluid poflefled of peculiar proper¬
ties. It feems, however, to have been known to Dr
Rutherford of Edinburgh, as early as the year 1772,
as appears from his thefis publiflred in that year, in
which he fpeaks of the effedls of combuftion .and re-
3'1 fpiration on the air of the atmofphere.
Methods of 2. There are various methods by which this gas may
procuring {jg obtained, a. The procefs recommended by Ber-
thollet is.the following: Take a quantity of mufcular
flefh, or the fibrous part of the blood, which has been
well waftied. Cut the flefh into fmall bits ; introduce
it into a retort, or a matrafs to which a ground tube
has been adapted. Pour over it diluted nitric acid,
expofe it to a heat of about too0, and place the beak of
the retort or the end of the tube in the pneumatic
apparatus, that the gas which comes over may be re-
I S T R Y.
ceived in proper veffels. The gas thus obtained, is Azotic Gas,
a%otic gas. b. If fulphuret of potafh be expofed to the v-
air of the atmofphere, inclofed in a bell-glafs, over
water \ or, if fulphuret of iron be formed into a pafte
with water, and treated in the fame way, and allowed to
remain for fome days, the quantity of air within the glafs
is greatly diminiihed, in confequence of part having
been abfotbed, and what remains is azotic gas. c. WThen
the air of the atmofphere is iacloled in the fame way, and
expofed to the adfion of phofphorus, it alfo fuffers dimi¬
nution, part being abforbed. Azotic gas only remains. ^
3. Azotic gas, like common air, is invifible and ela-properti£S,
flic, and may be in definitely condenfed and dilated. Its
fpecific gravity is lefs than that of atmofpheric air. It
is eftimated by Mr Kirwan at 0.00120, which is in
the proportion of 985 to ioooj but according to
Lavoifier’s experiments, it is to atmofpheric air as
942.6 to 1000, which makes its fpecific gravity only
0.00115.
This gas is unfit for combuftion. If into a jar or
phial, filled with azotic gas, a lighted candle be intro¬
duced, it is immediately extinguilhed.
This gas is alfo extremely noxious to animals, and
is therefore totally unfit for refpiration. 3^3
4. No attempts which have yet been made, have fuc-B a fmple
ceeded in decompofing azote, or the bale of azotic lub^ance*
gas. It muft therefore be admitted among the num¬
ber of fimple fubftances. It has never been obtained
in a feparate ftate. It is therefore when it is com¬
bined with caloric, that is, in a gafeous ftate, that we
are acquainted with its properties j and from its being
unfit for refpiration, it derived its name. Some che-
mifts have indeed confidered it as a compound fub-
ftance. Dr Prieitley fuppofed that it confifted ef
phlogifton and oxygen gas. On this account he cal¬
led it phlogiflhated air. According to the Stahlian
theory, the procefs of combuftion is the feparation of
phlogifton from the burning body. Oxygen gas, hav¬
ing a ftrong affinity for phlogifton, combines with it
during the combuftion, and is even fuppofed to contri¬
bute to the feparation of the phlogifton, by its affinity
for it. And whep this air is faturated with phlogifton,
the procefs of combuftion is at an end. The air that
remains after this procefs is azotic gas. This theory,
when firft announced by Dr Prieflley, w'as pretty ge¬
nerally received *, but future experiments foon de-
monftrated, that the quantity of air in which a com-
buftible body wTas burnt, diminifhed both in bulk and
in weight } and therefoie proved that the air, inftead
of receiving any addition, was on the contrary depriv¬
ed of fomething.
Achard, about the year 1784, concluded, from fome
experiments which he had made, that azotic gas con-
filts of water and fire. This theory has been fupport-
ed by Weftrumb, and more lately by Wiegleb. Ac¬
cording to the experiments on which thefe chemifts
reft the truth of their theory, azotic gas is always the
refult when fleam is made to pals through red hot
earthen, or even metallic tubes ; but a feries of very
accurate experiments, inftituted by the affociated Dutch
chemifts, clearly proved that no azotic gas tvas pro¬
duced, when the inftruments employed were impene¬
trable by air *. Dr Prieftley had long before fhown, * Annal <Ii
that in fimilar experiments, when he employed earthen* V01-
ware retorts, containing moift clay, and expofed themxx''1'p*3U‘s
to
Azotic Gas.
# Annul, de
Clin. vol.
xxxiv. p. 3.
| Ibid. vol.
xxxv. p. 23
554
Combina¬
tions
.355
With calo-
355
With oxy-
gen in dif¬
ferent pro¬
portions.
357 .
Properties.
C H E M I
to a temperature above boiling heat; inftead of va¬
pour iliumg from the beak of the retort, a quantity of
air, which was nearly equal in weight to the quantity
of water introduced, palled over. The conclulion
which he drew from thefe experiments, was, that the
water was converted into air ; for he found that it
poiTelTed nearly the fame properties as common air.
But he proved afterwards by more accurate experi¬
ments, that water had made its way through the pores
of the veffel, and that its place was fupplied by the ex¬
ternal air which was forced in by the preffure of the
atmofphere. For it was clearly afcertained by the ex¬
periments of the Dutch chemilts, that no gas was ob¬
tained, while perfectly found glafs or metallic tubes
were employed.
Another theory has been propofed, of the compo-
fition of azotic gas, by Girtanner *. He fuppoles that
azotic gas confifts of hydrogen and oxygen gas, having
a fmaller proportion of oxygen gas than what enters
into the compofition of water -f* But the experiments
of other chemifts, as thofe of Berthollet and Bouillon
.Lagrange, have afforded no fuch refult (b).
5. There is no perceptible action between light and
azotic gas. Combined with caloric, we have already
feen it may be indefinitely expanded, but without un¬
dergoing any change in its properties.
Azotic gas, from its being found in fuch abundance
in the air of the atmofphere, no doubt a£ts lome im¬
portant part in the economy of nature. It is given
out, or feems to be given out, in great quantity du¬
ring the decompofition of animal and vegetable mat¬
ters •, but during thefe proceffes, it is the oxygen
of the atmofpherical air which is abforbed, and thus
the refiduary air is azotic gas. The bafe of azotic
gas is unknown, and chemifts are ftill unacquainted
with its affinities.
Azotic gas combines with oxygen in different pro¬
portions, and forms compounds very different in their
nature and properties. In one proportion it conftitutes
the air of the atmofphere, in another, what is called
nitrous oxide, and in a third nitrous gas. 'Ihefe we
(hall examine in their order in the following feftions.
Sect. I. Of sItmospheric AIir.
1. The air of the atmofphere is compofed of azotic and
oxygen gafes. This is an invilible elaftic fluid, which
may be indefinitely compreffed and dilated. The foe-
cific gravity of atmofpheric air is 0.0012, or about 816
times lighter than water.. This is to be undet flood
when the temperature is between 50° and 6o°, and
when the barometer is at 30 inches. The preffure of
the air of the atmofphere is nearly equal to iflb. on
every fquare inch.
2. Till the difcoverics of modern chemiftry, atmo-
pheric aiq was confidered as one of the four firaple ele¬
mentary fubftances, of which all bodies are compofed.
But the experiments and refearches of Prieftley and of
Scheele fully demonftrated the exiftence of two fepa-
rate fubftances, totally diftinft from each other in their
nature and properties. Oxygen gas, one of the com¬
ponent parts of atmofpheric air, was, according to Dr
Prieftley, completely freed from phlogifton ; and hence
S T R Y. 49\3
he calls it dephlogifticated air, which was in an em> Azotic Gas.
nent degree, fit for refpiration and combuftion ; but
azotic gas, the other component part, was funpofed to
be faturated with phlogifton, and therefore unfit, as it
was found to be, for thefe purpofes. To the latter,
the azotic gas, Scheele gave the name of foul air. 358
3. According to the experiments of Lavoifier, the Proportions
proportions of the two gafes which exift in atmofpheric 0* azotf-
r. r 0. 1 r and oxygen
air, are 73 parts or azotic gas, and 27 or oxygen gas. 0,afe3 ’4>
But according to later experiments the proportions are ‘
found to be 78 of azotic gas, and 22 of oxygen gas
by bulk ; or by weight, 74 of azotic and 26 of oxy¬
gen gas. , " 35f>
The proportions of thefe two gafes in atmofpheric Alwaysr
air are uniform and conftant. They have been found ‘
to be nearly the fame in all parts of the world, and in
all leafons of the year, where experiments have been
made. 3^?
4. A queftion has arifen among philofophers concern- Conltim-
ing the conllitution of the atmofphere, whether ^ts h-re-
component parts are to be eonfidered merely as a me¬
chanical mixture, or as a chemical combination. To
the latter opinion the greater number of chemifts are
inclined, from the conilancy of the proportions of the 3^r
component parts of the atmofjjhere ; thefe parts always t0
being found in the fame proportion at all heights, and rn]-cal co~m_
never feparating according to their fpecific gravities j bination,
from its poffeffing diftincft properties, and from its con¬
tinuing the fame, whatever proceffes are carried on in
it y or whatever proportions of oxygen may be abforb¬
ed during thefe proceffes. 3^2
A contrary opinion has been adopted by Mr Dal-
ton, which he has endeavoured to eftabliffi by fome mixture,
very acute mathematical reafoning. According to
this ingenious hypothefis, the elaftic fluids which exift
in the atmofphere, have no mutual aiftion whatever.
The particles of one fluid are only attracled and re¬
pelled by each other, but are not afted upon by the
particles of another fluid. The particles of the differ¬
ent fluids, with regard to each other, are fubjeft to the *Manclep¥
laws of inelaftic bodies *. Mem. vor.
v- p- 535*
Sect. II. Of Nitrous Oxide Gas.-
, 1 363
I. This gas is moft readily obtained by decompofing Procels for!
nitrate of ammonia, a fait compofed of nitric acid and 0^.tainlӣ
ammonia, the properties of which will be afterwards1 ^ Sa'
particularly detailed. The cryftals of this 1’alt are put
into a retort, and expofed to a temperature between
340° and 500°. It very foon melts after the heat is
applied, and a great quantity of gas is emitted, at fli rt
in the form of white fumes, but afterwards transparent
and colourlefs. This may be received in jars over wa¬
ter in the ufual way. This is the nitrous oxide gas,
the gafeous oxide of azote, or, as it has been called by
fome, from the pleafurable fenfations it excites on be¬
ing refpired, the gas of paradfe. The firft part of the
gas which comes over is not quite fo pure as w'ben it
is given out flowty, and when it is tranfparent. When
therefore it is refpired, care ihould be taken to fepa-
rate wffiat comes off firft, from the reft. This gas, as'
is obvious from the procefs, is obtained by the decom-
pofitioa of the nitrate of ammonia 3 but the change
which
("b) The component parts of water are oxygen and hydrogen, as w§ ffiall find afterwards.
y
494 C H E M I
Azotic Gas. which takes place will be better underftood, when we
   come to treat of the fait itfelf, being previoufly ac-
r quainted with its condituent parts.
Difcovery. 2. This gas was called by Dr Prieftley dephlogifti-
cated nitrous gas j and it was difcovered by Wm in the
year 1776. Its component parts were afcertained by the
alTociated Dutch chemifts 5 but its nature and proper¬
ties were more fully and precifely inveftigated by Mr
^Refearebes, Davy
i8°®. In its phyfical properties, this gas refembles com-
p.355- mon air. It is elailic, tranfparent, and colourlefs.
roperties. The ppecific gravity> as it has been eftimated by Mr
Davy, is 0.00197. One hundred cubic inches.of it
weigh 50.20 grs. The component parts of nitrous
oxide gas are 63 of azote, and 37 oxy.8en £as*
Some combuftibles burn in this gas nearly as well as
in oxygen gas, but with this difference, that they muff
be in a ftate of ignition.
Pyrophorus, which fpontaneoufty inflames fo low as
the temperature of 4®° attnofpheric air, will not
burn in nitrous oxide gas, till it is raifed to a tempe¬
rature above 212°. A burning taper introduced into
pure nitrous oxide gas, burns at firft with a brilliant
white light, and fparkles as in oxygen gas ; but as the
combuftion goes on, the flame gradually lengthens,
and is furrounded with a pale blue light.. Phofphor.us
burns in it with a brilliancy not much inferior to its
366 combuftion in oxygen gas,
£ffe&s in 4. It was at firft fuppofed that this gas is unfit for re-
refpiring it.fpiration> but the experiments of Mr Davy have fhewn
the contrary 5 and the fingular eftefts which it produ¬
ces on the animal frame have excited much intereft.
prom thefe experiments, and from many others which
have been fince repeated, it appears that it may be re-
fpired for fome minutes without injury.. In fome cafes
It produces no effedt wrhatever 5 but, in general,, the
fenfations it excites are fimilar to thofe of intoxication j
but they are rarely followed by its unpleafant effedts.
Mr Davy defcribes his own feelings when he refpired
this gas, in the following words.
u Having previoufly clofed my noftrils and exhaufted
my lungs, I breathed four quarts of nitrous oxide.from
and into a filk bag. The firft feelings were giddinefs,
fenfe of fullnefs of the head, and indiftindt fenfation; but
in lefs than half a minute, the refpiration being continu¬
ed, they diminifhed gradually, and were fucceeded by
a fenfation analogous to gentle preflure on all the
mufcles, attended by a highly pleafurable thrilling,
particularly in the cheft and the extremities. The ob-
iefts around me became dazzling, and my hearing more
acute. Towards the laft infpirations, the thrilling in-
creafed, the fenfe of mufcular power became greater,
and at laft an irrefiftible propenfity to aaion was indul¬
ged in ; I recoiled! but indiftindtly what followed ; I
know that my motions wTere various and violent.
“ Thefe effedts very foon ceafed after refpiration.
In ten minutes I had recovered my natural ftate of
mind. The thrilling in the extremities continued
longer than the other fenfations.
« This experiment was made in the morning ; no
languor or exhauftion was confequent, my feelings
S T R Y.
throughout the day were as ufual, and I paffed the Azotic Gat
night in undifturbed repofe * ""
But although it may be refpired for a fhort time with RejcJchet%
impunity, not more than 3 or 4 minutes, yet animals
that are confined in it foon become reftlefs and uneafy,
and at laft expire. From this therefore it appears that
it is unfit for the fupport of animal life, and perhaps
could not at all be refpired, if the lungs were previ¬
oufly exhaufted of atmofpheric air. 367
5. The tafte of the nitrous oxide gas, when in a ftate Tafte and
of purity, is diftindtly fweet to the tongue and palate j
and it has an agreeable odour. Mr Davy obferves,
that he often thought it produced a feeling fomewhat
analogous, as he expreffes it, to tafle in its application to
the lungs ; for in one or two experiments he perceived
a diftindl fenfe of w;armth in the cheft f. t AW.
6. Water abforbs the nitrous oxide gas in confiderableP 46°’
proportion. When the water is agitat:eft» 0>54 Parts js abforbed
of its bulk, or 0.27 of its weight, combine w ith it. by water.
The water becomes fw7eetifti, and the whole of the gas
may be expelled from it unchanged, by boiling.
7. No change takes place upon this gas by the adlion
of light, but when it is expofed to a high temperature,
as when the electric fpark is fent through it, or when it
is made to pafs through a red-hot porcelain tube, it is
decompofed, and converted into common air and nitric
acid.
Sect. III. Of Nitrous Gas.
369
1. If a quantity of pure copper filings be put into a How pro*
matrafs or retort, and diluted nitric acid be poured over cured,
them, a violent effervefcence takes place, and a great
quantity of gas is evolved. This is nitrous gus. It
may be obtained alfo, by fubftituting for the copper
other metals, as iron, filver, and mercury.
This gas is mentioned by Dr Hales, but it is to the
labours of Dr Prieftley that we are. indebted for the
knowledge of its nature and properties. . 370
2. This gas is an elaftic, colourlefs fluid, which has Properties,
no fenfible" tafte, and does not redden the tin&ure of
turnfole (c).
According to Mr Kirwan, the fpecific gravity of
nitrous gas is 0.001458, but by Mr Davy’s eftimation
it is 0.001343. The weight of 100 cubic inches of
it is 34.26 grs. and it is compofed of55'95 oxy£>eib
and 44.05 azote %. This gas is totally unfit for refpi- j 7^,
ration. iVnimals that breathe it are inftantly fuffocat- p. 565.
ed.
Some combuftibles burn in this gas. Phofphorus,
when introduced into it in a ftate of adftive inflamma¬
tion, burns with almoft as much vividnefs as in oxygen
gas 11. Homberg’s pyrophorus, a fubftance which || 75/7,
takes fire when expofed to the air, when introduced p. 135*
into this gas, inftantly becomes red, and burns very vi¬
vidly. In this experiment, and in the former with the
phofphorus, thefe fubftances combine rvith the oxygen
of the nitrous gas,' w’hile heat and light are emitted and
azotic gas is left behind. 371
3. Nitrous gas, when expofed to the a&ion of heat, by Adhon o.
being made to pafs through a red-hot porcelain tube,hea *
undergoes
(c) This is a teft for acid fubftances, which will be mentioned particularly afterwards.
1
Hydrogen
Gas.
* Lagrange.
vol. i. p.
122.
37*
Combines
with oxy¬
gen.
. 373
Hiftory.
C H E M I
undergoes no change*. It is abforbed by water.
When the water is freed from air, it abforbs about
of its bulk of nitrous gas, at the common temperature,
and when it is boiled or frozen, the gas feparates un¬
changed. The water thus impregnated with nitrous
gas, has no peculiar tafte, nor does it alter the colour
of vegetable blues.
4. When a quantity of atmofpherical air is introduced
into a jar containing nitrous gas, a red colour appears
from the mixture of the two gafes ; they are diminilh-
ed in bulk, and heat is evolved. Fhe produfl is ni¬
trous acid. If oxygen gas be employed in place of at-
mofpheric air, the whole of the two gafes will be con¬
verted into a liquid. The diminution of julk is owing
to the condenfation of the elaftic fluids, and the evo¬
lution of caloric muft be afcribed to the change of
ft ate, from that of elaftic fluid to that of liquid.
Azotic gas alfo enters into combination with oxy¬
gen in a different proportion from what has been ftated
above, forming nitrous and nitric acids ; but thefe will
come more properly to be treated of among the clals
of acids.
The following table exhibits at one view the differ¬
ent proportions of oxygen and azotic gafes in the com¬
pounds formed by thefe two fubftances.
100 cubic inches.
Atmofpheric air
Nitrous oxide
Nitrous gas
Nitric acid
Weight in
grains.
31*10
50.20
34.26
76.00
In 100 grams,
Proportions of
Azote. Oxygen,
73.00
63-30
44.05
29.50
27.OO
36.70
55-95
70.50
374 „
Method of
procuring.
Chap. VI. Of HYDROGEN GAS.
1. This gas has been long known under the name of
the fire-damp of the miners. Its combuftible property
is defcribed in the works of Boyle and Hales, of Boer-
haave, and of Stahl 5 but it was not till the year 1766
that its properties were particularly afcertained, and
the difference between it and atmofpheric air pointed
out by Mr Cavendifti. Its properties and combina¬
tions were more fully inveftigated by Prieftley and
Scheele, Senebier and Volta, under the name of in-
fiammable gas or air. It is now diftinguifhed by the
name of hydrogen gas, and its bafe by that of hydrogen.
Like the two former, oxygen and azote, it is ne¬
ver obtained in an uncombined ftate. Its properties
can only be examined in the ftate of gas.
2. Hydrogen gas may be obtained in a ftate of toler-
ablepurity by the following procefs. Take one part of
clean iron filings, and introduce them into a tubulated
retort, and add two parts of fulphuric acid previoufly
diluted with four times its bulk of water. A violent
effervefcence immediately takes place, and great abun¬
dance of air bubbles make their efcape. Put in the
ftopper of the retort, and place the beak of it under the
fhelf in the pneumatic trough, and let the gas which
comes over be received in proper veffels. The gas
which is thus obtained, is hydrogen gas, which is dif-
tinguilhed by the following properties.
5 T R Y. 495
3. In its phyfical properties it refembles common air. Hydrogen
It is invifible and elaftic, and may be indefinitely com-, t
preffed and expanded.
Its fpecific gravity has been varioufly eftimated, Properties,
owing, perhaps, to its different degrees of purity.
According to Lavoifier, it is 0.000094, which is nearly
12 times lighter than atmofpherical air 5 but, accord ¬
ing to Mr Kirwan, it is 0.0001 o.
Hydrogen gas is unfit for fuppovting combuftion.
If a lighted candle be fuddenly plunged in a veffel fill¬
ed with hydrogen gas, it is immediately extinguiihed j
or if an inverted jar filled with hydrogen gas be fud¬
denly brought over a lighted candle, it is extinguiihed
in the fame way. The latter experiment is the raoft
effe&ual, on account of the fmall fpecific gravity of
the hydrogen gas, which is prevented from efcaping
by rifing upwards when the jar is inverted.
It is alfo unfit for refpiration.
When fmall animals are enclofed in a veffel filled
with this gas, they are foon thrown into convulfions,
and expire. Scheele, however,, who firft made the
attempt, breathed it feveral times without much in¬
jury. Fontana made the fame experiment, and he fup-
poi'es that this was owing to the common air in the lungs
before reipiration of the hydrogen gas j for when he
made a full expiration, before he began to breathe the
hydrogen gas, he could only infpire it three times,
and thefe three produced great languor and oppreflion
about the breaft. This is confirmed by Mr Davy of
the royal inftitution, who, in fome experiments on him-
felf found, that after having exhaufted the lungs as
much as poffible, he could not refpire this gas for half
a minute. It produced uneafy feelings in the cheft,
momentary lofs of mufcular power, and fometimes a
tranfient giddinefs *. From thefe experiments, there-* Davys
fore, it may be concluded, that hydrogen gas is total- R‘fearcbe,i
ly incapable of fupporting animal life. ^ p‘
4. But although hydrogen gas be unfit for the fupport is cotnbuf-
of combuftion, or for reipiration, yet it is itfelf a highly tible,
combuftible fubftance. If a jar be filled with hydro¬
gen gas, and a burning taper be applied, the gas will
take fire, and burn with a flame which is more or lefs
coloured according to the purity of the gas. When
the gas is in the pureft ftate that can be obtained, it
is of a white colour; but when it holds charcoal in
folution, it is of a reddifh colour. 377
5. Hydrogen gas, if other gafes be ntirely excluded, Combines
undergoes no change when it is kept in contadl withwith water
water, nor is any part of it abforbed by the water : preffure.
But when artificial preffure is employed, water is faid 373
to abforb a third part of its bulk of the gas. No per- A remedy
ceptible change is obferved in the tatte of the water m dlfeafe*
thus impregnated with hydrogen gas 5 it is recom¬
mended by Mr Paul as beneficial in nervous diforders,
and in inflammatory fevers f . ]Phil. Mag;
Hydrogen gas, on account of its being fo much v. xv. p 93.
lighter than atmofpherical air, has been employed for the Y.J'llyeH
purpofe of filling air balloons. When perfedlly pure,
it is 12 or 13 times lighter than the fame bulk of at¬
mofpherical air; but, in the ufual way of obtaining
it, the fpecific gravity of hydrogen gas is feven or
eight times lefs than that of common air. See Aero¬
station. 380
6. If hydrogen gas and atmofpherical air be mixed to- F-xplod**,
gether, they remain unaltered j but if one part of oxy¬
gen
49(>
CHEMISTRY.
Hydrogen
Gas.
38i
With at-
mofpheric
air.
382.
And with
oxygen gas,
gen gas, and two parts of hydrogen gas, be introduced
into a phial, and a burning taper be applied to its mouth,
the mixed gafes will explode with a loud noife, and
the bulk will be greatly diminifhed. The whole of
the oxygen of the atmofpheric air difappears, and the
azotic gas only remains. If one part of oxygen gas
■and a- parts of hydrogen gas be mixed together in a
phial, and exploded in the lame way, they both difap-
ipear. This may be proved by mixing the two gafes in
a jar over water or mercury, and exploding them by
means of the eleftric fpark. The gafes difappear;
a vacuum is confequently formed in the jar, and the
water or the mercury, by the preffure of the air, is
forced up. If the experiment has been made over mer¬
cury, and if the infide of the jar was previoufly free
from moifture, drops of water will appear, which have
been formed by the combination of tbe two gafes.
Water, therefore, is compofed of oxygen and hydrogen
gas. This is a cafe of true combuftion. Oxygen com¬
bines with the combuftible body j light and caloric
are evolved, and the refult of this a£!ion and combina¬
tion is one of the produfts of combuftion, namely wa¬
ter. The difcovery of the compofition of w^ater, un¬
doubtedly one of the moft important in modern che-
miftry, will be the fubjedl of the following fe£tion.
Sect. I. Of IVater.
*0 +
Importance 1. Water a£Is fo important a part in many chemical
in chemif- aftions and combinations, that its nature and properties
try’ fhould be-eaily known- Before the difcoveries of mo¬
dern chemiftry, it was confidered as a fimple iubftance,
and one of the four elements which enter into the con-
ftitution of all bodies in nature.
The fortunate difcovery of the compofition of wa¬
ter, is undoubtedly one of the moft important which
-has been made in chemical fcience. We have already
mentioned, that the produft of oxygen and hydrogen
gafes, when exploded together, is water (d): but in
a fubjeft of fo much importance, it will be neceftary
to enter more into detail j and this we ftiall do, ift, by
Hating the experiments on the bafis of which the proofs
of its compofition reft 5 and zdly, by giving a ftiort
hiftorical view of the progrefs of the difcovery.
2. Various experiments have been made to afcertain
this fa£t; but thofe which were made by Lavoifier be¬
ing on a larger fcale, and performed wdth fucb pre¬
cautions as to infure accuracy and precifion, the fol¬
lowing account of them will be the more fatisfac-
tory.
Proof6f the Exjber. a. Take a porcelain or glafs tube from 8 to
compofi- i2 lines diameter, and place it acrofs the furnace
tionofwa- with a gentle inclination from E to F (e).
ter by ana-
lyfis.
I. Proof of tbe Compofition of Water.
The higher extremity of the tube is then luted to the Hydrogen
glafs retort A, containing a known quantity of diftill-, ^ ^
ed water. To the lower extremity F is luted the p,ate
worm SS, the lower end of which is fixed in the neck CXLII.
of the bottle H, which bottle has the bent tube KKFig .3.
fixed to a fecond opening. "I his bent tube is intended
to carry off any elaftic fluids which may efcape into
the bottle H. ’ A fire is then lighted in the furnace
EFCD, Sufficient to keep the tube EF red hot, but
not to melt it. The water in the retort A is kept
boiling by a fire in the furnace WXX. The water
is gradually changed into fleam by the heat of the two
furnaces. It pafles through the tube EF into the worm
SS, where it is condenfed, and then drops into the bot¬
tle H. When the whole water is evaporated, and all
the communicating veffels are emptied into the bottle
FI, it is found to contain exactly the fame quantity
which was put into the retort. This experiment there¬
fore is a fimple diftillation.
Exper. b. Every thing being difpofed as in the laft
experiment, let 28 grains of pure charcoal, broken in¬
to fmall parts, and which has been expofed to a red
heat in a clofe veffel, be introduced into the tuoe Eh.
The experiment is then performed in the fame manner
as the former. The water is evaporated, and a por¬
tion of it is again condenled in the wormSS, and then
falls into the bottle H j but at the Erne time a confi-
derable quantity of an elaftic fluid efcapes through the
tube KK, which is received in veffels. When the wa¬
ter is entirely evaporated, and the tube examined, the
28 grains of charcoal have wholly difappeared.
When the water in the bottle H is examined,
it is found to have loft 85-7 grains of its weight;
and when the elaftic fluid which paffed off by the tube
KK is weighed, it is found to weigh 113.7 grains,
which is exactly the weight which the water has loft,
added to the 28 grains of charcoal which had difap¬
peared. The elaftic fluid, on examination, is difco-
vered to be of two kinds j namely, 144 cubical inches
of carbonic acid gas weighing 100 grains, and 380 cu¬
bical inches of a very light gas weighing only 13.7
grains. Now 100 grains of carbonic acid g&s confift
of 72 grains of oxygen, combined with 28 grains of
carbone. It is therefore evident, that the 28 grains of
charcoal muft have acquired^ 72 grains of oxygen
from the water. It is alfo evident, that 85.7 grains
of water are compofed of 72 grains of oxygen, com¬
bined with 13.7 grains of a gas capable of being
burned.
Exper. c. Every thing being put in the fame or¬
der as in the two former experiments, with this differ¬
ence, that inftead of the 28 grains of charcoal, 274
grains of foft iron, in thin plates rolled up fpirally, are
introduced into the tube EF. The tube is kept red-
hot wffiile the water is evaporating from the retort.
After
(v) Sir Ifaac Newton having difcovered in the courfe of his optical inveftigations, that combuftible bodies
poffefs the greateft refrattive powder in proportion to their denfity, and obferving the great re ra ing power o
water, conjeflured with aftoniffiing fagacity that it muft contain a combuftible fubftance In the fame way he
was led to a fimilar coniedlure wdth regard to the diamond 5 both which have been venhe . 1 j ir K
(z) The tube EF, if of glafs, ftiould be fuch as can bear a ftrong heat without melting. H lhou|d .all° “
coated over with a lute compofed of clay and powdered ftone-ware } and to prevent it from bending uring
experiment, it muft be fupported about the middle by an iron bar.
<2
Hydrogen
Gat.
38 s
Proved by
fynthefis.
CHEMISTRY.
497
After the water has been diftilled, it is found to have
loft 100 grains. The gas or elaftic fluid weighs 15
grains, and the iron has gained 85 grains additional
weight, which put together make up 100 grains, the
weight which the water has loft. The iron has all
the qualities which it would have received by be¬
ing burned in oxygen gas. It is a true oxide (or
calx) of iron. We have the fame refult as in the
laft experiment, and have therefore another proof
for concluding, that 100 grains of water confift of 85
grains of oxygen, and 15 of the bafe of inflammable
gas.
We have now exhibited two fufficient proofs, that
water is compofed of oxygen and hydrogen 5 but as the
compofttion of water is fo interefting and important a
fubjefr, M. Lavoifler was not fatisfied with thefe proofs
alone. He juftly concluded, that if water be a com¬
pound of two fubftances, it ought to follow', that by
reuniting thefe two fubftances, w'ater would be produ¬
ced. He accordingly proved the truth of this conclu-
fton by the following experiment.
Exper. d. He took a large cryftal balloon A, fig. 4.
containing about 30 pints, and having a large mouth ;
round which was cemented the plate of copper BC,
pierced with four holes, through which four tubes pafs.
The firft tube H/6 is intended to exhauft the balloon
of its air, by adapting it to an air pump. The fecond
tube gg communicates with a refervoir of oxygen gas
placed *at MM. The third tube is connefted
with a refervoir of hydrogenous gas at NN. The
fourth tube contains a metallic wire GL, having a
knob at its lower extremity L, from which an eleftric
fpark is pafled to 0, in order to fet fire to the hydrogen
gas. The metallic wire is moveable in the tube, that
the knob L may be either turned towards S, or away
from it, as there is occafion. We muft alfo add, that
the three tubes H£, gg, dYi'b are furniftied with ftop-
cocks.
It is neceflary that the oxygen gas, before being
put into the refervoir, fhould be completely purified
from carbonic acid. This may be done by keeping
it for a long time in contaft with a folution of cauftic
potafh. The hydrogen gas ought to be purified in the
fame manner. The quantity employed ought to be
double the bulk of the oxygen gas. It is beft procured
from water by means of iron, as was defcribed in Ex¬
periment Third.
Great care muft alfo be taken to deprive the oxygen
and hydrogen gas of every particle of water. For
this purpofe they are made to pafs in their way to the
balloon A, through falts which have a ftrong attraftion
for water j as the acetite of potafh (a compound of
vinegar and vegetable alkali), or the muriate or nitrate
of lime (the muriatic or nitric acid combined with lime).
Thefe falts are difpofed in the tubes MM and NN of
one inch diameter, and are reduced only to a coarfe
powder, that they may not unite into lumps, and in¬
terrupt the paffage of the gafes.
Every thing being thus prepared for the experiment,
the balloon is exhaufted of its air by the tube H h, and
is filled with oxygen gas. The hydrogen gas is alfo
prefied in through the tube D J by a weight of one
or two inches of water. As foon as the hydrogen gas
enters the balloon, it is fet fire to by an eledlric fpark.
The combuftion can be kept up as long as we pleafe,
Vox.. V. Part II.
by fupplying the balloon with frefh quantities of thefe Hydrogen
two gafes. As the combuftion advances, a quantity Ga'*' .
of water is collected on the fides of the balloon, and
trickles down in drops to the bottom of it. By know¬
ing the weight of the gafes confumed, and the weight
of the water produced, we {hall find that they are pre-
cifely equal. M. Lavoifier and M. Meufnier found
that it required 85 parts by weight of oxygen gas, and
15 parts of hydrogen gas, to produce 100 parts of wa-
ter.
Thus we have complete proofs, both analytical and
fynthetical, that water is not a fimple elementary fub-
ftance, as it has been long fuppofed, but is compound¬
ed of two elements, oxygen and hydrogen.
But although the knowledge of the component parts
of water wras finally confirmed by Lavoifier and his
friends, we fhall find that fcience is indebted for its ori¬
gin and progrefs, chiefly, if not entirely, to the Eng-
lifh philofopers.
2. HiJJory of the Difcovery of the Compofition of Water. ^
1. So early as the year 1776, an experiment was made Combuftio*
by Macquer, to afcertain what would be the produftof hyd.r°*
of the combuftion of hydrogen gas. He accordingly
fet fire to a bottle full of it, and held a faucer over the
flame, but no foot appeared upon it as he expe&ed,
for it remained quite clean j and was bedewed with drops
which were found to be pure water. Various conjec¬
tures were now formed about the nature of the produ£l 387
of the combuftion of oxygen and hydrogen gafes. By Conjec-
fome it was fuppofed the carbonic acid gas j by otherstures-
it w7as conje&ured it would be the fulphurous or ful-
phuric acid. The latter was the opinion of M. La¬
voifier. Such wrere the experiments and opinions of
the French chemifts, previous to the year 1781. . 3ss ,
2. About the beginning of that year, Mr Warltire, a Experiment
le&urer in natural philofophy, had long entertained byWarl-
an opinion that the combuftion of hydrogen gas with
atmofpheric air might determine the queftion, whether
heat be a heavy body. Apprehenfive of _ danger jn
making the experiment, he had for fome time declin¬
ed it} but was at laft encouraged by Dr Prieftley, and
accordingly prepared an apparatus for the purpofe.
This was a copper veflel properly fitted, and filled
with atmofpherical air and hydrogen gas, which u'as
exploded by making the ele&ric fpark pafs through it.
A lofs of weight of two grs. was obfervcd after the
combuftion. A fimilar experiment was repeated in
clofe glafs veffels, which, though clean and dry before
the combuftion, became immediately wret with moif-
ture, and lined with a footy matter. This footy mat¬
ter, Dr Prieftley afterwards fuppofed, proceeded from
the mercury which had been employed in filling the
veffel. _ 38$
3. During the fame year, Mr Cavendifh repeated the By Cave*-
experiments of Mr Warltire and Dr Prieftley. Hedilh.
performed them feveral times with atmofpheric air
and hydrogen gas, in a veflel which held 24,000 grs.
of water, and he never could perceive a lofs of weight
more than y gr. and often none at all. In all thefe
experiments, not the leaft footy matter appeared in the
infide of the glafs. To examine the nature of the dew
which appeared in the infide of the glafs, he burnt
500,000 grain meafures of hydrogen gas with about zi
tiijjes that quantity of common air j and in this com-
j R, bullion
498 ■ G H E M
Hydrogen bufiion he obtained 135 §rs* 0^'vater» which had nei-
' Gas. t]ier ta{|e nor fmell j and when it was evaporated, left
v' jio fenfible lednnent. It feemed to be pure wa¬
ter.
In another experiment, he exploded in a glafs globe,^
19,500 grain meafures of oxygen gas, and 37,000 of
hydrogen gas, by means of the electric fpark. I he
refult of the experiment was 30 grains of water, which
contained a fmall quantity oi nitric acid. The expe¬
riments of Mr Cavendilh were made in the year 1781)
and they are undoubtedly conclufive with regard to
-9o the compofltion of water. _
Mr Watt’s 4. It would appear, that Mr VvTatt entertained tne
views. fame ideas on this fubjefl. When he rvas informed
by Dr Prieftley of the refult of thefe experiments, he
obferves; “ Let us confider what obvioufly happens
in the deflagration of hydrogen and oxygen gafes.
Thefe two kinds of air unite with violence, they be¬
come red hot, and when cooling totally dilappear.
When the veffel is cooled, a quantity of water is found
in it equal to the weight of the air employed. The
water is then the only remaining produft of the pro-
cefs ; and water, light, and heat, are all the produdls,
unlefs there be fome other matter fet free, which efcapes
our fenfes. Are we not then authorized to conclude, that
water is compofed of oxygen and hydrogen gales, de¬
prived of part of their latent or elementary heat 5
that oxygen gas is compofed of water, deprived of its
hydrogen, and united to elementary heat and light}
and that the latter are contained in it in a latent ftate,
fo as not to be fenfible to the thermometer or to the
eye. And if light be only a modification of heat, or
a circumitance attending it, or a component pait of
the hydrogen gas, then oxygen gas is compoied of
■water deprived of its hydrogen, and united to elemen-
Tbil. Tranf. tary heat.”
1784, Thus it appears that Mr Watt had a juft view of the
P* 383’ compofition of w ater, and of the nature of the procefs by
which its component parts pafs to a liquid ftate from
391 that of an elaftic fluid.
Lavoifier’s 5. Towards the end of the fame year, M. Lavoifier
experi- made forae experiments, the refult of which fur-
racnts- prifed him •, for the product of the combuftion of the
oxygen and hydrogen gafes, inftead of being lulphuric
or Sulphurous acid, as he expeaed it, was pure, water.
This led him to procure an apparatus, with which the
experiment might be performed on a large fcale, and
with more accuracy and preciiion. Accordingly the
experiments w?hich we have already detailed were per¬
formed on the 24th of June 1 783, in prefsnee of feveral
academicians, and alfo of Sir Charles Blagden, wrho
was at that time in Paris-. A fimilar experiment was
afterwards performed by M. Monge, with the fame
refult ; and it was repeated again by Lavoifier and
Meufnier, on a fcale fo large as to put the matter be¬
yond a doubt. The conclufion, therefore, from the
whole was (as has been fiated in detailing the experi¬
ments themfelves), that water is compofed of oxygen
and hydrogen j and this fa<ft, we believe, fince Dr
Prieftley’s death, is univerfally admitted.
Fourcroy’s, 6. If farther proofs were neceffary to eftabhfti the fa£t,
we might refer the reader to an elaborate memoir on
the combuftion of hydrogen gas in clofe veftels by the
celebrated chemifts Fourcroy, Vauquelin, and Seguin,
I S T R Y.
which was read at the academy of fciences in the year , Carhone, _
1790*. • 1 r vn * Annal.de
7. Water exifts in three different ftates.; in the iolid voL
ftate or ftate of ice \ in the liquid, and in the ftate ot viii. p. 230.
vapour or fleam. Its principal properties have already 393_
been detailed, in treating of the effects of caloric. ItWawrm^
affumes the folid form when it is cooled down to the
temperature of 3 2^. In tins ftate it mcreales m bulk,
by which it exerts a prodigious expanfive force, which
is owing to the new arrangement of its particles, which
affume a cryftalline form, the cryftals crofting each ^
other at angles of 6o° or 120°. The fpecific gravity of Ice.
ice is lefs than that of water. _ 395
When ice is expofed to a temperature above 320, it Water or
abforbs caloric, which then becomes latent, and is con- Ad¬
verted into the liquid ftate, or that of water. At the
temperature of 42~F\ water has reached its maximum
of denfity. According to the experiments of Lefevre
Gineau f, a French cubic foot ofdiftilled water, taken f Journ- Je
at its maximum of denfity, is equal to yelb. 223 grs. P/jj/tom.
French, =529,452.9492 troy grains. An Engliftix 1X-P-D1’
cubic foot at the fame temperature weighs 437,102.4946
grains troy. By Profeffor Robifon’s experiments it is
afeertained, that a cubic foot of water at the tempera¬
ture of 550 weighs 998.74 avoirdupois ounces, of
437'5 g^l^s troy each, or about ounce lefs than
1000 avoirdupois ounces. 396
When water is expofed to the temperature of 212°, Vapour,
it boils, and if this temperature be continued, the
whole is converted into an elaftic invifible fluid, call¬
ed vapour or fleam. This, as has been alieady {hewn,
is owing to the abforption of a quantity of caloric,
wLich is neceffary to retain it in the fluid foim. In
this ftate it is about 1800 times its bulk when in the
ftate of water. 1 his (hews what an expanfive foice it
muft exert when it is confined, and hence its applica¬
tion in the fleam engine, of which it is the moving
power.
Sect. II. Of Ammonia.
Hydrogen alfo enters into combination with azote,
and forms a compound of great importance. When
hydrogen and azotic gafes are mixed together, no change
takes place, nor has any procefs been yet discovered by
which thefe two gafes can be direaiy combined j but
when thefe are in their nafeent ftate, as it is called,, or
in the moment of evolution from the bodies with which
they were formerly in combination, they unite together
and form ammonia, or the volatile alkali.. It is de-
monftrated alfo by diredl experiment, that this fubftance
is compofed of thefe two gafes j but for the properties
of it. we muft refer to the chapter on alkalies, where
they will be fully detailed.
Chap. VII. Of CARBONE.
l It may appear at firft fight furpnfing, that the The dia-
diamond, one of the hardeft and moft indeftruftible mond con>Q
fubftances in nature, fliould be arranged among com-b^bic.
buftible bodies. This, however, was conjedlured by
Newton, when be confidered its great refradbng power,
referring it to the general law, that combuftible bodies
have this power in greatefl perfeaion. The fagacious
conjecture
C H E M I
Carbone, conjeflore of tWs great pWIofopher has been fully ve-
IL—  ' rified. The firft experiment to afcertaxn the combuiti-
bility of the diamond, was made in the year 1694, in
,o8 the prefence of Cofmo III. grand duke of Tufcany, by
Proved by the Florentine academicians. In this experiment, the
experiment. expofed to the heat of a burmng-glals, nrlt
became dull and tarnilhed, loft of its weight, and was
at laft entirely diflrpated, without the fmalleft reiidue.
Some vears afterwards, a feries of experiments was
made before Francis I. emperor of Germany, m which
diamonds were confumed in the heat of a furnace. In
the year 1771, Macquer firft obferved the diamond
fwell up and burn with a very fenfible flame. Rouelle
the younger, Cadet, Mitouart,. and Darcet repeated
the fame experiments, all which tended to eftabliui
the volatility and combuftibility of the diamond.
But it is to the celebrated Lavoifier that we are in¬
debted for afcertaining the nature and produdl of this
399.
'Found m
the torrid
zone.
400
Form.
401
Properties.
402
Froduifl of
its com-
buftion.
combuftion.
2. But for the fake of comparifon, we ihall mention
fome of the general properties of the diamond. I his
precious ftone is found in the warmer regions of the
earth, and chiefly in the Eaft Indies and the Brazils.
It is found cryftallized in regular oftahedrons, which
is its primitive form j that of the molecules is the re¬
gular tetrahedron. The moft common form is the fix-
fided prifm, terminating in a fix-fided pyramid. What
are called fpheroidal diamonds, have 48 curvilineal, tri¬
angular faces, which form of cryftal is owing, accord¬
ing to Hauy, to a regular decrement, which may be
determined by calculation. The lapidaries are well
acquainted with the direftion of the laminm of the
diamond, becaufe in that direftion it is found to be
moft eafily polifhed. The hardeft diamonds are found
to have their fibres twifted, which by the lapidaries are
called natural diamonds.
■?. The diamond is the hardeft body known. It can
only be poliftied with the powder of itfelf, which is
procured by rubbing one diamond againft another.
The fpecific gravity of the diamond is 3.5. One of
its moft remarkable properties is its brilliancy. VV hen
expofed to the light of the fun for fome time, and
afterwards carried into a dark place, it appears lumi¬
nous, fo that it has the property of abforbing light.
It becomes very fenfibly electric by friftion, and is
therefore a non-condu£Ior of eleflricity.
4. As it was now afcertained, that the diamond ex¬
pofed to a ftrong heat was fufceptible of combuftion, and
might be entirely diflipated, Lavoifier direfted his at¬
tention in the year 1772 to difcover the product which
was thus obtained •, and he found by experiment, that
the quantity of the diamond, expofed to the heat or a
burning-glafs in oxygen gas, confumed, was in exaC,
proportion to the quantity of air which was abforbed.
This air was converted into carbonic acid. gas (Fj.
The quantity of the carbonic acid obtained being found
proportional to the quantity of diamond confumed, it
was concluded that diamond was nothing elfe but pure
carbone. This furnilhed a ftriking analogy between
the diamond and charcoal, from the combuftion of
which a fimilar produft is obtained. An experiment
s T R~ Y. 499
made by Guyton in the year 1785, and a firnilar one
repeated in 1797 by Mr Tennant, proved that tne
diamond is combuftible, and that it burns like charcoal
when thrown into melted nitre. The conclufion from
which was, that the diamond and charcoal are com-
pofed of the fame fubftance. . 4^3
e.Weftiall find in inveftigating the properties of A iunp.e^
charcoal in the following feftion, that the one is a
fimple, the other a compound fubftance, which will
enable us to explain the remarkable difference between
many of the properties of the diamond and charcoal. 4o4
Charcoal burns in the heat of an ordinary fire, but the Compared
diamond requires for its combuftion a temperature not whkh
lefs than 5000°; nor is the difference between thete is a com_
two bodies in fpecific gravity, hardnefs, and colour, p0und.
lefs ftriking. Lavoifier had afcertained that 100 parts
of carbonic acid contained
28 charcoal,
72 oxygen.
100
In the experiments made by Guyton on t.ie dia¬
mond, it appeared that carbonic acid gas is compoied
of
17.88 diamond,
82.12 oxygen.
If then 100 parts of carbonic acid gas, are compofed xxxi. p. 99.
of the fame proportions of conftituent parts, and thele
proportions are obtained both by the combuftion or the
diamond and charcoal, it muft neceffanly follow that
the charcoal, which requires a finaller proportion ot
oxygen to make up the 100 parts of carbonic acid .gas,
muft contain the difference of the quantity of oxygen
between the quantity with which it combines^ and the
quantity neceffary to faturate the diamond. 1 hus, dia¬
mond requires 82.12 of oxygen, and charcoal requires
only 72, the difference between which is 10.12, whicn
muft have been previoufly combined with the char¬
coal before combuftion. The 28 parts of charcoal,
then, are compofed of
17.88 diamond,
10.12 oxygen.
28.00
Hence it follows, that 100 parts of charcoal confift of
63.86 diamond,
36.14 oxygen.
100.00
From this account, therefore, of the nature and pro¬
perties of the diamond, it muft be confidered as a
fimple fubftance, and that fubftance which has received
the name of carbone in the new chemical nomenclatuic .
very different in its properties from charcoal, which is
a compound fubftance, and has received the name ol
3 R 2 oxide
(f) Carbonic acid gas, as will appear
afterwards, is compofed of carbone and oxygen.
5°o C H E M I
Carbone, oxide of carbone or diamond (g). But we fliall con-
fider the properties of the compound more particularly
in the following fe&ion.
Sncr. I. Of the Combinations of Carbone with
Oxygen .
4°5
Charcoal
very abun¬
dant.
405
Method of
preparing
and puri-
fying.
407
Properties.
Carbone enters into combinations with oxygen. 1. In
the Hate of charcoal or oxide of carbone; 2. In the
form of gas, which has been denominated the gafeous
oxide of'carbone, or carbonic oxide ; and 3. In another
proportion conftituting carbonic acid, which alfo exifts
in the gafeous ftate. The nature and properties of the
two firft wre are now to examine : the lalt will be treat¬
ed of under the clafs of acids.
I. Of Charcoal.
1. Charcoal exifts in great abundance in animal and
vegetable matters, and it is obtained by the partial de-
compofttion of thefe fubftances. It may be procured
by burning wood in clofe veffels ; and the matter that
remains after this combuftion, is a black, fhining,
brittle fubftance, which is well known under the name
of charred wood, or charcoal. To obtain charcoal
pure, it mull be repeatedly wrafhed with pure water,
and be afterwards expofed for feme time to a ftrong
heat in clofe veffels. Thus prepared, if it be entirely
deprived of moifture and excluded from air, it may
be expofed to the ftrongeft heat without any change.
2. Charcoal is a good conductor of cledlricity.
When it is new made, it is found to have the property
of removing the difagreeable odour with which animal
matters beginning to putrify, clothes and other fub-
ftances, are tainted. On account of this property, per¬
haps, and alfo an account of its mechanical effedls, it
is greatly recommended as an excellent teeth pow'der.
Charcoal leerns to be quite indeftruftible. This is the
heft method of preferving wood from decay, which is
expofed to the effedls of air and moifture. Stakes
charred on the outlide, have remained in the ground
for fome thoufand years, and are ftill In perfeft pre-
fervation. This feems to have been a common prac¬
tice among the ancients.
3. Charcoal has neither tafte nor fmell. It is info-
luble in water, but it abforbs moiflui'e in confider-
able proportion. When it is wrell dried, charcoal at¬
tracts the air very greedily. A piece of charcoal well
dried, placed under a jar over mercury, abforbs the
air, and the mercury afcends rapidly; but if a little
water be introduced into the jar, the charcoal abforbs
the moiflure, gives out the air, and the mercury de-
fcends. In fome experiments made with this view, it
appeared that charcoal abforbed four times its bulk of
air ; and when the charcoal was plunged into water,
a fifth part of this air was difengaged, which being
examined, a quantity of oxygen had difappeared. In
another experiment, the charcoal was introduced into
a velfel filled with oxygen gas, when it abforbed eight
times its bulk of the gas, and being plunged into wa-
S T R Y.
ter, gave out a fourth part. Thefe experiments were Carbone,
made by Delametherie %. *-1 j
The experiments of Senebier feem to prove, that it ^p^°r ,n'^e
was only the oxygen gas of the atmofpheric air that s/v. v0 ' %
was abforbed by charcoal; but it has been fince de-
monftrated, that this only takes place when the char¬
coal is hot. The atmofpheric air is abforbed un¬
changed when the charcoal is cold.
4. When the temperature of pure charcoal is raifed
to rednefs, and is introduced into a jar of oxygen gas,
it burns rapidly, giving out brilliant fparks, but with
little flame. The charcoal difappears, and the oxygen
gas is totally changed. By its combination with the
charcoal during the combuftion, it is converted into a
peculiar gas which has received the name of carbonic
acid gas, the component parts of which were difcover-
ed by M. Lavoifier, to be
28 charcoal,
72 oxygen.
100
The properties of this acid will be fully defcribed in
its place among the clafs of acids.
5. It is generally agreed among chemifts, that char¬
coal confifts of oxygen and carbone ; but a controverfy
at prelent exifts, whether hydrogen does not, in all 408
cafes, enter into its compofition ? Charcoal prepared Compoli-
in the common way, always contains a portion of hy-uon*
drogen. It is therefore to be confidered as a triple
compound, confifting ol carbone, oxygen, and hydro¬
gen. But according to the experiments of Deformes
and Clement, charcoal expofed for fome time in a
clofe veflel to a very ftrong heat, is entirely deprived
of its hydrogen f. This, however, does not correlpond f *
with the experiments of Mi Cruicklhank, in which the vol.
gafes obtained from charcoal in all ftates of preparation ^
were always found to contain hydrogen.
6. There is no direfl aiftion between carbone and
azotic gas; but by the a£lion of a third Jubilance.
Compounds of azote, hydrogen and carbone, which are
combined alfo with a greater or leffer proportion of
oxygen, frequently exift among vegetable and animal
matters.
II. Of the Gafeous Oxide of Carbone.
I. A peculiar inflammable gas, which has been con-
fidered of the fame nature with the carbonated hydro¬
gen gas to be defcribed in the next fedtion, was an¬
nounced by Dr Prieftley, from the manner of its pro-
dudlion and properties, as a confirmation of the truth
of the phlogiftic theory. His experiments were foon
repeated by many other chemifts, and particularly by
Mr Cruicklhank of Woolwich, who publilhed a very
fatisfa£lory account of the nature, compofition and pro¬
perties of this gas. He gave it the name of the
feous oxide of carbone. He confidered it as confifting
of carbone united with oxygen ; the oxygen and car¬
bone exifting in it being nearly in the proportion of
two.
(g) In the prefent nomenclature of chemiftry, the word oxide is ufed to denote the combination of oxygen
with a bafe, the product of w'hich combination exhibits no acid properties, as in the prefent cafe, the combina-*
tion of oxygen with carbone or diamond.
CHEMISTRY.
Carbone.
410
Methods of
procuring.
* Ann. de
Chim. tom.
xxxix.
P- 45-
411
Properties.
* llli.
p. 5S.
two to one. Dr Prleftky obtained it from the gray-
oxide, or forge fcales of iron and charcoal. Mr
Cruickfhank alfo obtained it by a fimilar procefs. He
employed the oxides of zinc and copper •, the Hack
oxide of manganeie and litharge. 1 he g<is which is
obtained from thefe fubftances, is a mixture of carbo¬
nic acid and the gafeous oxide of carbone. Mr Cruick-
fliank found, that the oxides which moft readily part
with their oxygen, afford the greateft proportion of
carbonic acid ; but the oxides which retain their oxy¬
gen more ftrongly, give the greateft proportion of the
gafeous oxide of carbone. At the beginning of the
procefs, carbonic acid comes over in greateft abun¬
dance-, it then diminifties, and afterwards nothing but
the gafeous oxide is extricated.
It is alfo obtained by expofing to a ftrong heat one
part of pure charcoal and three parts of carbonate^ of
lime, ftrontites, or barytes, in an iron retort. The
carbonic acid which is in combination with the earths,
is partly difengaged unchanged, and partly decompol-
ed by the charcoal, and converted by the aftion of the
charcoal into the gafeous oxide of carbone. I he gas
which is obtained in this procefs is compofed of one
part of carbonic acid and five parts of galeous oxide
The fame gafes are alfo obtained, by employing iron
filings with the earthy carbonates, and the quantity is
confiderably increafed when pure iron is ufed. Mr
Cruickfhank and the French chemifts alfo obtained it,
by making carbonic acid gas pafs through red hot
charcoal, in an iron or porcelain tube. The carbonic
acid is decompofed, and the gaieous oxide is formed.
The carbonic acid which is mixed with the gafeous
oxide obtained in all thefe proceffes, may be feparated
by walhing the gas with lime water, and the galeous
oxide remains in a ftate of purity.
2. This gas is invifible and elaftic like common air.
Its fpecific gravity is 0.001167-, 100 cubic inches
weigh 30 grains. *
It is unfit for refpiration. Small animals introdu¬
ced into it are iuftantaneoufly fuffocated -, and in fome
perfons who attempted to breathe it, it produced faint-
nefs and giddinefs. Deiormes and Clement, think that
it is probably owing to this gas difengaged from burn¬
ing charcoal, that hidden death is induced in clofe
apartments. It is not altered by parting it through a
red-hot tube, nor does it undergo any change by being
expofed to light ; and it is neither inflamed nor dimi-
nilhed by parting the eleftric fpark through it. 1 his
gas in contadl with common air, when fet fire to, burns
■with a blue flame. When it is made to travel fe a red-
hot tube full of air, it produces flight detonations. The
refidue of thefe combuftions is carbonic acid and azote.
3. With oxygen gas, if in confiderable proportion, the
combuftion is very rapid ; a red flame is produced, and
the whole of the gas is confumed. The refidue in this
combuftion is carbonic acid f.
According to Mr Cruickfhank, the gafeous oxide of
carbone is a compound of carbone and oxygen. Thirty
grains of it obtained from charcoal and metallic oxides,
required 1 ? grains of oxygen to faturate it, and the
quantity of carbonic acid produced was 35*5* lhili:y
grains olrtained from iron filings and earthy carbonaU,
required 13.6 grains of oxygen, which gave 43*2giains
of carbonic acid.
4. But according to the experiments and concltmons
Soi
Carbons.
41:
of Berthollet, the gafeous oxides of carbone contain a ^
certain portion of hydrogen in their compolition. This
quantity, he thinks, amounts to about .04—He
diftinguiflies two fpecies of inflammable gas, which
contain carbone the one confifts entirely of hydrogen
and carbone, which he propofes to denominate carbo-
noted hydrogen gas, which will be treated of in the next
fedlion. The other fpecies of inflammable gas is aha
formed of hydrogen and carbone, but contains a certain
portion of oxygen. To this he propofes to give thfc
name of oxycarbonated hydrogen gas. But the refults
of the experiments of Cruicklhank and others do not
correfpond with the experiments and conclufions of Ber¬
thollet, in admitting any proportion of hydrogen as a
component part of his oxycarbonated hydrogen gas, or
of the gafeous oxide of carbone. But for an account ot
his obfervanons and reafonings on this iubjedl. See
Memoires de I'lnjlitut Nation, tom. iv. p. 269, 3*9»
and 325.
Sect. II. Of Carbonated Htdrogen Gas.
1. If a quantity of wet charcoal be introduced into Method of
a retort, and exported to a red-heat, a great quantity ofPrQCum'S'
gas paffes over, which may be colleded in jars in the
pneumatic apparatus, in the ulual way. It may be al¬
fo obtained by making the vapour of water parts through
red-hot charcoal in a porcelain or iron tube placed
acrorts a furnace. The water is decompofed ; the hydro¬
gen, one of its component parts, combines with the car¬
bone of the charcoal. The gas obtained by thefe pro¬
ceffes has been called /ight inflammable air. A fimilar
gas may be procured from ether, fpirits of wine or
camphor, by making the vapour of therte fubftances
pafs through red-hot porcelain tubes. T his gas, from
its greater fpccific gravity, has been called heavy in¬
flammable air. The proportions of the fubftances which
enter into the compofition of this gas vary confiderably
according to the procefs employed, or the materials
from which it is obtained. It is the fame gas which is
given out in great abundance during hot weather, from
ftagnant waters. ... . 4r3
2. This gas is like common air, invifible and elaftic. properties;
When a candle is applied to it, it burns with a blue,
lambent flame. If it be mixed with atmortpheric air,
the combuftion is more rapid and brilliant, and ftul
more fo when it is mixed with oxygen gas, but with¬
out any detonation. The produft of this combuftion
is carbonic acid and water. The oxygen combines
partly with the carbone, and forms carbonic acid $ and
partly with the hydrogen, and forms water.
3. It is totally unfit for refpiration. Animals intro¬
duced iiv.it are inftantly fuffscated. It is alfo unfit
for fupporting combuftion.
One of the moft remarkable properties of this gas
is, when it is mixed in a tube with common air or oxy*.
gen gas, about |ds its bulk of the latter, and fired by
the eledlric fpark, there is a confiderable increafe of
volume. < 4i4.(
The component parts of carbonated hydrogen gascomp0g„
obtained from different fubftances, as they have been tion.
afcertained by Mr Cruickfhank, are the following.
When it is procured from ether, camphor, or ftagnated
water, it contains the greateft proportion of carbone.
The fpecific gravity is 0.000804, and it is to common air
nearlv
5°2
Phofpho- nearly as two to three. One part by weight of hydro
, rus‘ gen gas holds in folution 54 parts of carbone *,
loo parts contain 52.35 carbone,
9.60 hydrogen,
38.05 water inftead of vapour.
CHEMISTRY.
100.00
When it is obtained from ether, the fpecific gravity
is 0.000787 :
100 parts contain 45 carbone,
15 hydrogen,
40 water.
When it is obtained from fpirit of wine, the fpecific
gravity is 0.00063 :
100 parts contain 44.1 carbone,
11.8 hydrogen,
44.1 water.
The lighteft is obtained from diftilling wet charcoal, Phofpho-
or paffing the vapour of water through red-hot char- , rus-
coal. It contains one part by weight of hydrogen gas,
holding three parts of carbone in lolution. The fpeci¬
fic gravity is 0.000554. It is to common air nearly as
one to two •,
100 parts contain 28 carbone,
9 hydrogen,
63 water f.
  f Nicbol/ont
IOO ’Journal,
Mr Cruickfhank has difcovered a very eafy method vo ' v- P‘ r*
of diftinguilhing the gafeous oxide of carbone from
the carbonated hydrogen gas. A mixture of the
latter and oxymuriatic acid gas may be exploded by
pafling ele&ric fparks through it. But a mixture of
oxymuriatic acid gas and the gafeous oxide of carbone
fuffers no change by the ablion of eleftricity.
The following table, drawm up by Mr Cruickfhank,
exhibits the refults of his experiments on thefe two
gafes.
100.0
A Table, /hewing the Analyfis, <b'c. of the different Species of Carbonated Hydrogen Gas, or Hydrocarbonates,
and of the Gafeous Oxide of Carbone.
Gafes, and the different
Subftanees from which
the Gafes are obtain
ed, 8tc.
Weight of
10a Cubic
Inches, or
Grains.
Grains.
Proportion of Oxy¬
gen necefiary
to faturate 100
Meafures of the
Gas. '
Chian, of
Grains
Meaf.
Products when combined with Oxygen.
Carbonic Acid
  K. 
In Vol.
Meaf.
In Chian.
Grains.
Water
produc¬
ed.
Grains.
Water held
in Solution
by the Gas.
Grains.
Hence the Gafes confift of
Oxyg.
Carbon.
Hydro
Water.
Pure carbonated hy
drogen gas from
camphor, &c.
— from ether
— from alcohol
 wet char¬
coal
Gafeous oxide from
charcoal and me
tallic oxides
 from
iron filings, and
carbonate of lime,
or barytes
21
20
16
14>5
3°
3°
176
170
118
66
44
40
59,8
58
40
22,4
116
108
75
40
76
92
54.5
50.5
36
19
35.5
43,2
18
18
J3
about
8
8 or 9
9
7
proby none
none
none
none
about
15
21 -}-
11
9
7
nearly
15
8,6
2-f-
3
*,9
G3
! +
8 or 9
8
7
9
uncer¬
tain
Chap. VIII. Of PHOSPHORUS.
. 4I5
Iliftory. j. This fingular fubftaneexvas accidentally difcovered
in 1677 by an alchemilt of Hamburg, named Brandt,
when he was engaged in fearching for the philofo-
pher’s ftone. Kunkel, another chemift, who had feen
the new' product, affociated himfelf wdth one of his
friends named Krafft, to purchafe the fecret of its pre¬
paration *, but the latter deceiving his friend, made the
purchafe for himfelf, and refufed to communicate it.
Kunkel, who at this time knew nothing farther of its pre¬
paration, than that it w’as obtained by certain procef-
fes from urine, undertook the talk, and fucceeded. It
I
is on this account that this fubftance long wTent under
the name of'Kunkel’s phofphorus. Mr Boyle is alio
confidered as one of the difeoverers of phofphorus.
He communicated the fecret of the procefs for pre¬
paring it to the Royal Society of London in 1680. It
is afferted, indeed, by Krafft, that he difcovered the
fecret to Mr Boyle, having in the year 1678 carried
a fmall piece of it to London, to Ihew it to the royal
family ; but there is little probability, that a man of
fuch integrity as Mr Boyle, would claim the difeove-
ry of the procefs as his own, and communicate it to the
Royal Society, if this had not been the cafe.
Mr Boyle communicated the procefs to Godfrey
Hankwitz, an apothecary of London, who for many
years
Pllofp'lO-
rus.
416
Exifts in
bones.
* Mem. de
I'lnji. tom.
ii. p. 282.
417 ,
Procefs for
obtaining
CHE M I
years fupplted Europe with phofphorus j and hence it
went under the name of Englijh phofphorus. Many
chemifts now attempted to produce phofphorus, and
different proceffes had been publifhed for the purpofe ;
but it would appear that they rarely fucceeded.
In the year (737, a ftranger having fold to the
French government a procefs for making phofphorus,
the Academy of Sciences charged Dufay, Geoffrey,
Duhamel, and Hellot, to fuperintend it. The latter
publithed an account of the experiment, which iuc-
ceeded. Rouelle the elder exhibited phofphorus which
he had prepared, in the courfe which he opened at
Paris fome years after. In the year 1743* Margraaf
made a great improvement in the procefs, but hill it
continued to be obtained with difficulty, and in very
fmall quantity. It was not till 30 years after, that
confiderable improvement was made in the procefs for
procuring phofphorus.
In the year 1774, the Swediffi chemitts, Gahn and
Scheele, made the important difcovery, that phofpho¬
rus is contained in the bones of animals, and they im¬
proved the proceffes for procuring it.
2. The moft convenient procefs for obtaining phof¬
phorus feems to be that recommended by Fourcroy and
Vauquelin *. Take a quantity of burnt bones and re¬
duce them to powder. Put 100 parts of this powder
into a porcelain or {tone-ware bafon, and dilute it with
four times its weight of water. Forty parts of fulphu-
ric acid are then to be added in fmall portions, taking
care to ttir the mixture after the addition of every por¬
tion. A violent effervefcence takes place, and a great
quantity of air is difengaged. Let the mixture remain
for 24 hours, ftirring it occafionally, to expofe every
part of the powder to the action of the acid. T. ne
burnt bones confill of the phofphoric acid and lime •,
but the fulphuric acid has a greater affinity for the
lime than the phofphoric acid.. The 3aion of the lul-
phuric acid uniting with the lime, and the fepaiation
of the phofphoric acid, occafion the effervefcence.
The fulphuric acid and the lime combine together, be¬
ing infoluble, and fall to the bottom.
°Pour the whole mixture on a cloth filter, fo that the
liquid part which is to be received in a porcelain vef-
fel may pafs through. A white, powder, which is the
infoluble fulphate of lime, remains on the filter. Af¬
ter this has been repeatedly waffied with water, it may
be thrown away, but the water is to be added to that
part of the liquid which paffed through the filter.
Take a folution of fugar of lead in water, and pour
it gradually into the liquid in the porcelain bafon. A
white powder falls to the bottom, and the.lugar of
lead muff be added fo long as any precipitation takes
place. The whole is again to be poured.upon a niter,
and the white powder which remains is to be uell
waffied and dried. The dried powder is then to be
mixed with one-fixth of its weight of charcoal powder.
Put this mixture into an earthen-ware retort., and
place it in a fand bath with the beak plunged into a
veffel of water. Apply heat, and let it be gradually
increafed, till the retort becomes red hot. As the
S T R Y. ~ 503
heat increafes, air-bubbles ruffi in abundance through Phofpho-
the beak of the retort, fome of which are inflamed , 11^'
when they come in contact with the air at the furface
of the water. A fubftance at laft drops out fimilar to
melted wax, which congeals under the water. This is
phofphorus. _ _ 41S _
In this {late the phofphorus is not quite pure. It is and purt-
generally mixed with fome charcoal powder, and a f>inSlt' -
portion of half burnt phofphorus, which give it a brown
colour. To have it quite pure, melt it in warm wa¬
ter, and {train it feveral times through a piece of iha-
moy leather under the furface of the water (h). To
mould it into flicks, take a glafs funnel with a long
tube, which muft be flopped with a cork. Fill it with
water, and put the phofphorus into it. Immerfe the
funnel in boiling water, and when the phofphorus is
melted and flows into the tube of the funnel, then
plunge it into cold water, and when the phofphorus
has become folid, remove the cork, and pufh the phof-
phorus from the mould with a piece of wood. T hus
prepared, it muff be preferved in clofe veffels contain¬
ing pure water. ^ _ # 415
3. When phofphorus is perfedlly pure, it is femitranf- Properties-
parent, and has the confiftence of wax. It is fo foft
that it may be cut with a knife. Its fpecific gravity
is from 1.770 to 2.033. It has an acrid and dilagree-
able tafte, and a peculiar fmell fomewhat refembling
garlic. When a flick of phofphorus is broken, it ex¬
hibits fome appearance of cryffallization. Ihecry-
ftals are needle-lhaped, or long oftahedronsbut to
obtain them in their moft perfedl ftate, the furface of
the phofphorus, juft when it becomes folid, ftiould be
pierced, that the internal liquid phofphorus may flow
out, and leave a cavity for their formation.. . 420
4. WThen phofphorus is expofed to the light, it be- Ad ion 0.
comes of a reddiffi colour, wffiich appears to be an in- &
cipient combuftion. It is therefore neceffary to pre- 421
ferve it in a dark place. At the temperature of 99.0 heat*
it becomes liquid, and if air be entirely excluded, it
evaporates at 2190, and boils at 5540, -^} ^ie *'em*
perature of 430 or 440, it gives out. a white fmoke, _
and is luminous in the dark. I his is a flow combul-
tion of the phofphorus, which becomes more rapid as
the temperature is raifed. When phofphorus is heated
to the temperature of 14^°? ^ takes fire, bums with a
bright flame, and grves out a great quantity of white
fmoke. ,
Phofphorus enters into combination with oxygen,
azote, hydrogen, and carbone.
Sect. I. Of the Combinations of Phosphorus with
Oxygen.
Phofphorus enters into combinations with oxygen in
different proportions.
I. Oxide of Phofphorus.
When phofphorus is expofed to the light, or is kept in
water that is not freed from air, it foon becomes of a
white colour, having loft its tranfparency, and after¬
wards
(„) The leather (hould only be employed once, for the phofphorus uthich is ftraincd through it afterwards
will be coloured.
5 °4
C H E M
FhofpliO-
rus.
422
To fepa-
rate the
oxide.
wards changes to a brown. This is the firft combination
of oxygen with it, and being in the fmalleft proportion,
and giving no acid properties to the compound, it has
been denominated an oxide ofphofphorus. This {hews
that it is neceffary to keep it excluded from air and
light. But phofphorus thus changed on the furface
may be freed from that part w?hich is oxidated by a
very fimple procefs. Diflfolve the phofphorus in warm
W'ater, the w'hole melts except the oxidated part, w?hich
remains at the furface, becaufe it is not foluble at the
fame temperature.
II. Acids.
4*3 .
Production.
4*4
Splendid
combuf-
tlOVL
1. When phofphorus is burned in common air con¬
fined in a veflel, the combuftion is pretty rapid, and
continues till the whole of the oxygen be confumed.
A great quantity of wdiite fumes are produced, and
wdien thefe fumes are mixed w'ith water wdrich abforbs
them, it is found to have acid properties. This is the
phofphorous acid., in which the oxygen is in fmaller
proportion than in the following, but greater than in
the oxide.
2. But when a fmall bit of phofphorus is introduced
into ajar filled wuth oxygen gas at the temperature of
6o°, it dilTolves flowly, but does not appear luminous
till the temperature be raifed to So*, which .{hews that
phofphorus requires a higher temperature to burn in
oxygen gas than in common air. And if the phofpho¬
rus be introduced into the oxygen gas, wdiich is per-
feftly pure at a lower temperature, it undergoes no
change, gives out no fmoke, and is not luminous in
the dark. But when it is immerfed in a ftate of igni¬
tion into oxygen gas, it exhibits the moft brilliant
combuftion that can be conceived. The light which
is emitted is almoft as fplendid as that of the fun, and
is too powerful for the eye to bear. During this com¬
buftion the oxygen gas difappears, it lofes its gafeous
form, and becomes folid in combination with the phof¬
phorus. It ia during this change from the fluid to the
folid ftate that the caloric is emitted} and the light,
according to Gren’s theory of combuftion, is given
out by the phofphorus. The produft is a concrete
fubftance which adheres to the fides of the jar. This
is the phofphoric acid, in which there is a greater pro¬
portion of oxygen in combination with the phofphorus.
Thefe acids will be treated of in the chapter on acids.
Sect. II. Of Phosphorated Azotic Gas.
4*5
Phofphorus i. At firft fight it feems difficult to explain the reafon
combines ^at; phofphorus requires a higher temperature for its
tic^as*0” combuftion in oxygen gas than in common air. But
without the caufe of this fingular phenomenon appears by exa-
emitting mining the effefts of azotic gas on phofphorus. The
kght' phofphorus, which is readily converted into vapour at
a low temperature, combines with the azotic gas with¬
out combuftion, and therefore without giving out any
light. The azotic gas is thus faturated with the phof¬
phorus, and its bulk is increafed about ■3%-. The
combination is denominated phofphorated azotic gas.
2. When oxygen gas is introduced into ajar filled
with this gas, it becomes luminous, becaufe there is a
combuftion of the pho'fphorus which is held in folution
by the azotic gas. The combuftion is more rapid and
2
I S T R Y.
brilliant when the phofphorated azotic gas is let up in¬
to the jar of oxygen gas.
Phofph*.
rus.
Sect. III. Of Phosphorized and Phosphorated Hy¬
drogen Gas.
426
1. When a piece of phofphoius is put into ajar fil-Phofphorus
led with hydrogen gas, it does not appear luminous in chffolved 1*
the dark. But, after having remained for feveralhy roSeu
hours, part of the phofphorus is diflblved. When this8a5'
gas, to which Fourcroy and Vauquelin have given the
name of phofphorized hydrogen gas, is introduced into
a jar of oxygen gas, each bubble, as it paffes up and
comes in contact w'ith the gas, produces a very brilli¬
ant bluifh flame, which fills the whole veffel. This
effeft does not take place in atmofpheric air. This
gas holds in folution only a fmall proportion of phof¬
phorus ; but it is owing to the combuftion of this por¬
tion that the flame appears in the oxygen gas. This
gas has a lefs fetid odour than that wdiich is next to be
deferibed. It has, however, a flight finell of gar¬
lic * Ann. ete
2. Phofphorated hydrogen gas w^as difeovered by vo,•
M. Gengembre in 1783, by boiling a folution of pot-xx‘4^ 205
afti on phofphorus, and by Mr Kirwan in the follow-Hiftory.
ing year. Its nature and properties have been more
completely inveftigated by M. Raymond in tw^o pa¬
pers in the Annales de Chimie for 1791 and 1800. It
may be obtained by introducing a bit of phofphorus
into a jar of hydrogen gas (landing over mercury, and
melting the phofphorus by means of a burning glafs. 8
The phofphorus is thus converted into the ftate of va- Procefl’es
pour, when the hydrogen gas diffolves a much greater for obtain-
proportion. But a more fimple procefs has been re-fi’S^
commended by Raymond.
Take two ounces of quicklime, flaked in the air,
about 60 grs. of phofphorus, and half an ounce of wa¬
ter j reduce the whole to a pafte, and put it immedi¬
ately into a fmall glafs or ftone-ware retort, the body
of w’hich may be filled with the materials. Immerfe
the beak of the retort under water in the pneumatic
trough, and apply a moderate heat. As foon as the
retort is heated, the gas begins to come over j and
when the bubbles come to the furface of the water in
conta£f with the air, they explode with flame and
fmoke. When the gas pafles off (lowly the bubbles
are larger •, and when they reach the furface they ex¬
hibit an elegant appearance, forming, after explofion,
a beautiful coronet of white fmoke, which rifes with
an undulatoiy motion to the cieling, when the air is
dill. When this gas is brought into contact with oxy¬
gen gas, the combuftion is more rapid and more bril¬
liant.
The produfls of the combuftion of this gas are phof- pro4j,^9
phoric acid and w'ater. The phofphorus wThich is heldbyeom-
in folution by the hydrogen, combines wdth the oxy-bullion,
gen, and forms phofphoric acid ; while the hydrogen
unites with another portion of oxygen and forms
water.
This gas has a very fetid odour, which has fome re* p ^3°
femblance to the fmell of putrid fid). When pure wa- r°per ie'”
ter is agitated in contact with this gas, it abforbs about
one-fourth of its bulk at the temperature of 50°. The
colour of the folution is not quite fo deep as that of
roll
G H E M
Sulphur, roll fulphur. The fmell is ftrong and difagreeable,
’"‘'Y"-"*1 and the tafte extremely bitter. It does not appear lu¬
minous in the dark. But when it is expofed nearly to
the temperature of boiling, the whole of the phofpho-
rated hydrogen gas is driven off unchanged, and the
water remains behind perfectly pure. When the folu-
tion is expofed to the air, the oxide of phofphorus is
depofited, and the hydrogen gas efcapes *.
s°s
& Ann. de
Cbhn. vol.
XXXV. p.
234-
Sect. IV. Phosphuret of Carbone.
Phofphorus enters into combination with charcoal,
430 and forms what Prouft, who difcovered it, denomi-
How pro- nates phofphuret of carbone. It is produced during the
duced. dirtillation of phofphorus, and remains behind on the
leather, when it is {trained through it to purify it fitom
this fubftance. It is of a red colour, and does not
melt like pure phofphorus. If it be diftilled with a
gentle heat, there is feparated a fmall portion of phof¬
phorus which it contains in excefs. But the true com-
pound of phofphuret of carbone is not decompofed
Action of without a very ftrong heat. When the veftels have
heat. cooled there is found a light, flocculent powder, of a
lively orange red, which M. Prouft confiders as the
phofphuret of carbone. If it be expofed to a red heat
in the retort in which it is formed, the whole of the
phofphorus is driven off, and the charcoal remains be¬
hind. When this phofphuret is expofed to the open
air on a heated metallic plate, it burns rapidly j but
the charcoal which abforbs the phofphoric acid, as it
is formed, efcapes the combuftion. It lofes, in a fhort
time, the property of burning, by being expofed to
the air, and then it may be preferved without any rifle,
f Ibid.p. 44' of its catching fire fpontaneoufly f.
I S T R <Y.
zes into prifmatic needles. The cryftals are better Sulphur,
formed by pouring out part of the liquid fulphur as
foon as the furface has become folid. 435
4. If the heat be continued it becomes thick and^fPj1163
vifeid ; and if it be then poured into cold water, it re¬
tains its foftnefs, fo that it is employed for taking im-
preflions of feals and medals. In this ftate they are ^
called fulphurs. When fulphur is expofed to heat inlsfublim-
clofe veffels, it is volatilized or fublimed in the form eJ-
of a very fine powder, known under the name of
FLOWERS OF SULPHUR. v
Sulphur enters into combination with oxygen, azote,
hydrogen, carbone, and phofphorus. 438
The combination of fulphur wuth azotic gas has been With azotic
little examined. Part of the fulphur is diffolved, whenSa5,
it is heated in a veffel filled with the gas. This fulphu-
rated azotic gas, as it is called, has a fetid odour.
When the temperature is diminifhed, part of the ful¬
phur is depofited. It has been lately difcovered in the
mineral waters of Aix-la-Chapelle.—We fliall confider
the other combinations of fulphur in the following fec-
tions.
433
A fimple
Jubilance,
433
Properties.
434
Adlion of
heat.
435.
Cryftallizes,
Chap. IX. Of SULPHUR.
1. Sulphur is a fimple undecompounded combufti-
ble fubftance, wdrich is univerfally diffufed in nature ;
but moft: commonly in a ftate of combination with mi¬
neral, vegetable, or animal matters. It is found in
fome mineral waters, but in greateft abundance in vol¬
canic countries, where it is a valuable article of com¬
merce.
2. Sulphur, as it is extrafted from minerals and pu¬
rified by art, is a hard brittle fubftance of a yellow,
colour, which can be eafily reduced to powder. It is
always opaque, has a lamellated fradfture, and be¬
comes ele&rioby fri&ion. The fpecific gravity, after
it is melted, does not exceed 1.9907. It has no fmell,
and very little perceptible tafte. When it is rubbed
fome time, it is volatilized, and diffufes a peculiar and
{lightly fetid odour, by w'hich it is eafily diftinguiflied.
It leaves on the Ikin which has been in contact w ith it,
a very ftrong fmell, which remains for fome hours. It
is infoluble in wTater.
3. Light has no fenfible effeft on fulphur. But if a
roll of fulphur be held in the hand for a little, it be¬
gins to crackle, and at laft it breaks to pieces. When
a temperature equal to that of boiling water is applied
to fulphur, it melts, becomes liquid and tranfparent, and
changes to a brown red colour 5 but, on cooling, if the
fufion is not too long continued, it refumes the yellow
colour. If it be permitted to cool Howdy, it cryftalli-
Vol. V. Part II.
Sect. I. Sulphur combined with Oxygen.
439
1. When fulphur is kept fome time in fufion in an Oxide,
open veffel, it affumes a red colour, and becomes vifeid.
After it is cooled, it retains its red colour, which is ow¬
ing to the combination of oxygen in fmall proportion
with the fulphur. In this ftate it has been denomi¬
nated the oxide of fulphur. According to the experi¬
ments of Dr Thomfon, the oxide of fulphur, formed
by melting the fubftance in a deep veffd, is of a dark
violet colour, fibrous frafture, and tough confiftence ;
the fpecific gravity is 2.325. It contained 2,% per
cent, of oxygen. Another oxide, containing 6.2 per
cent, of oxygen, was formed by palling a current of
oxy-muriatic acid gas through flowers ot fulphur*. ,
2. When fulphur is burnt in the open air, it emitsxxi p' 20'^
a pale blue flame, wuth a great quantity of white
fmoke. When thefe fumes are mixed with water, it punu°in
is found to poffefs acid properties. This is a combina-common
tion of fulphur with a greater proportion of oxygen a‘r*
than exifts in the oxide, and is called fulphurous acid. 441
3. But when fulphur is burnt in oxygen gas, a very In oxygen
rapid combuftion takes place with a reddilh white Sas*
flame, and it combines with a greater proportion of
oxygen. When the fumes which are copioufly emit¬
ted during this combuftion are collected and mixed
with water, it exhibits the properties of an acid, which
is the fulphuric acid. Thus it appears, that fulphur
combines with oxygen in four different proportions.
In two of thefe, in which the proportions are fmalleft,
the compounds are denominated oxides; but in the
two others, in which the proportion of oxygen is in-
creafed, the compounds are acids, the properties of
which will be afterwards inveftigated.
Sect. II. Sulphurated Hydrogen Gas.
44 2
1. This gas may be procured by various proceffes. It Method of
may be obtained by making hydrogen gas pafs through
melted fulphur. In this way the hydrogen gas enters
into combination with fulphur. The fame gas may
alfo be obtained by melting together in a crucible
3 S equal
506
Sulphur.
443.
Properties.
444
.Compoli-
tion.
C H E M I
equal parts of iron filings and fulphur, by which means
a black brittle mafs is formed, which is to be reduced
to powder, and introduced into a glafs veflel (fig. 6.)
with two mouths, the one of which has a flopper A
and the other a bent tube B, accurately ground to
fit the mouths C, D. When the mixture of iron
filings and fulphur has been introduced into the phial,
the bent tube is to be fitted into the mouth, with the
other end under the furface of the water in the trough
E. The apparatus being thus prepared, pour in
muriatic acid through the other opening, and imme¬
diately clofe it with the ground ftoppei(._ The fulphu-
rated hydrogen gas is copioufly difengaged, and fills
the glafs jar F, which is previoufly placed on the
ftielf to receive it. This gas was formerly known by
the name of hepatic gas.
2. The odour is extremely foetid, refembling that
from the w&fhings of a gun, or from rotten eggs,
which is owing to the extrication of the fame gas.
The fpecific gravity of this gas is 0.00135.
It is unfit for refpiration, and a taper immerfed in it
is extiriguifhed, fo that it is alfo unfit for fupporting
combuftion. When it is inflamed in contaft with at-
mofpheric air or oxygen gas, it burns with a reddifh
blue flame, and depofits a quantity of fulphur. Sul¬
phur alfo is depofited by Ample expofure to the air.
From this it appears, therefore, that the affinity of hy¬
drogen for oxygen is ftronger than for fulphur. Dur¬
ing the comburtion, the hydrogen unites wdth the oxy¬
gen, and the fulphur is depofited. It is from this de-
pofition that the fulphur found about mineral fprings,
the waters of which contain this gas, is derived.
3 According to the experiments of Thenard, IOO
parts by vrelght of fulphurated hydrogen gas contain
70.8 57 fulphur,
29.143 hydrogen.
100.000 *.
4. Sulphurated hydrogen gas has the property of
diffolving phofphorus. Fourcroy and Vauquelin intro¬
duced pieces of phofphorus into a jar filled with this
gas over mercury. After the phofphorus had been
expofed to the gas fot twelve hours, the atmofpheric
air w’as admitted, and there inftantly appeared a bluifh,
voluminous flame. The bubbles of the gas diftuled in
phefylibrus. the air, prefented by day light a white vapour, which
feemed to adhere like vifcid matter to the furface of
the mercury ; but in the dark, exhibited a very bril¬
liant light. The mercury in the trough in which the
experiment was made, continued for feme minutes to
give out fparks of light by agitation. The hands
plunged into this gas, continued luminous for fome
minutes, and a fponge introduced into it retained the
j jhid vol. fame property for fome time in the air f.
xxi. p. 207. 5. Sulphurated hydrogen gas is very readily abforb-
ed by water, -and in this ftate it poffeffcs fome of the
properties of an acid. It changes vegetable blues to a
red colour.
, Sect. III. Carburet of Sulphur.
446
V.’kh car- x. Sulphur and carbone combine together at a high
bone in dif- temperature, and probably in different proportions j
DoSo^0’ one combinations is liquid, at the ordinary
Ann. de
Ttbim. vol.
xxxii. p.
267.
.445
Diffolves
S T R Y.
temperature and preffure of the atmofphere. This is Sulphur.
the carburet of fulphur. The following method
preparing it is given by Clement and Deformes, who
have particularly inveftigated the a£lion of fulphur and
charcoal. 447
2. Put a quantity of charcoal in fmall pieces, or in Prepara-
powder previoufly dried, into a porcelain tube, whichtl0n-
is to pafs through a furnace that it may be expofed to
a red heat. The gas from the charcoal is to be allowT-
ed to efcape, before the other part of the apparatus is
adjufted. To that extremity of the porcelain tube
which contains the charcoal, fit a long glafs tube, fuf-
ficiently wide to contain a number of fmall pieces of
fulphur, which may be puflied fucceflively into the
porcelain tube with an iron rod palling through a cork
which clofes the end of the tube. To the other ex¬
tremity there is to be fitted another glafs tube, bent
at the end, that it may be immerfed in a veffel of
water in the pneumatic trough. Heat is then to be
applied till the porcelain tube and the charcoal become ,
red-hot, when the pieces of fulphur are to be pulhed
{lowly forward into the tube, and when it aiffs on the
charcoal, a yellow' liquid of an oily appearance paffes
through the tube. The heat being continued, it eva¬
porates, and is condenfed in the water of the veffel in
which the tube terminates, traverfing it in globules
which colledt together at the bottom. 448
The fuccefs of this experiment is fomewhat doubt-Precautions
ful. When fulphur is expofed fuddenly to a ftrong
heat, in place of being fublimed, it appears in fome
meafure fixed, and becomes foft by fufion. Sometimes
it paffes too rapidly through the charcoal to unite with
it ; the pieces of fulphur, therefore, Ihould be flowly
introduced, and the tube in palling through the fur¬
nace, Ihould be inclined from that extremity at which
the fulphur is introduced.
3. When the carburet of fulphur is pure, it is tranf-Properties,
parent and colourlefs, but frequently has a greenilh-
yellow tinge. It has a difagreeable pungent odour.
The talk is at firlt cooling, but afterwards becomes ex¬
tremely pungent. It is heavier than water, does not
mix with it, and therefore remains at the bottom of
the veffel. The fpecific gravity of this liquid is vari¬
ous. In one trial it was found to be 1.3. 450
4. The carburet of fulphur evaporates at the ordi-Evaporates,
nary temperature of the atmofphere, and increafes its
volume nearly as much as ether. When a quantity of
this liquid in a veffel of water is placed under the re¬
ceiver of an air pump, and- the air exhaufled, it rifes
through the w'ater in bubbles, and affumes the gafeous
form} and when the preffure of the air is reftored,
the gas is inttantly condenfed, and returns to the liquid
ftate. _ . . 4SI
The carburet of fulphur burns with great facility, Combufti*
and during the combuftion it emits a ftrorg odour ofble.
fulphurous acid, depofits a little fulphur, which after- ^
wards burns, and there remains fome black charcoal
in its ufual combuftible ftate. The air which holds
carburet of fulphur in folution, burns quietly, but when
it is mixed with oxygen gas, and brought in contact
with a burning body, it explodes with prodigious vio¬
lence, and not without confiderable danger.
6. This fubflance unites with phofphorus, which it
very readily diffolves, but the folution is not more irir
flammable than the phofphoxus itfelf, It combines
alfo
Acids-
* dnn. Je
Chitn. vol.
xlii. p. 134,
45*
-Prepafa-
tians.
453
Combined
with ful-
phnr more
fulible.
Fourcroy
Connaifs.
Chitn. tom.
i. p. 20a.
G H E M
alib with a fmali quantity of fulphur, but without any
other change in its properties than becoming a little
deeper coloured. It feems to have no afrion on char¬
coal *.
Sect. IV. Svlpeurst of Phosphorus.
1. Sulphur and phofphorus combine together in all
proportions. If one part of phofphorus with eight
times its weight of fulphur, be put into a matrafs, with
32 parts of diililled water; on the application of a
gentle heat, the phofphorus melts and diffolves the
fulphur. The new' compound alfumes a yellow colour,
and remains fluid, till it is cooled down to the tem¬
perature of 770, when it becomes folid. This fub-
ftance is the fulphuret of phofphorus. In other cafes,
W'hen the proportion of phofphorus exceeds that of the
fulphur, it is called a phofphuret of fulphur.
2. The compounds of fulphur and phofphorus have
been particularly inveftigated by Pelletier, and he has
found that the compound is always more fufible than
either of the uncombined conflituents. The following
table exhibits the refults of his experiments-f-. '
8 Phofphorus
1 Sulphur
4 Phofphorus
I Sulphur
1 Phofphorus
4 Sulphur
1 Phofphorus’
1 Sulphur
1 Phofphorus
2 Sulphur
1 Phdfphorus’
3 Sulphur
remain fluid at 95®
59
SO
41
72
99
All thefe compounds, therefore, it mufl: appear, are
more fufible than the phofphorus itfelf, and much more
fo than the fulphur.
Danger in $• making thefe combinations, great caution
the procefs. fliould be obferved ; for if the heat be applied fudden-
ly, even when the fubftances are under water, a vio¬
lent explofion fometimes takes places, from the fudden
formation and extrication of the fulphurated and pho-
fphorated hydrogen gafes.
Chap. X. Of ACIDS.
Oxides! I* WE have feen, in defcribtng the different fab-
fiances which have been treated of in the five pre¬
ceding chapters, that they all combine with oxygen
in different proportions, excepting one. Hydrogen
combines with oxygen only in one proportion, and
I S T R Y.
5°7
this compound is water. The firft portion of oxy- Acids,
gen wTich combines with the other four fubftances, '
namely azote, carbone, phofphorus, and fulphur, forms
with them compounds which, poffefling no acid pro¬
perties, have received the name of oxides (1).
2. But w!hen thefe fubftances combine with a great- Acids,
er proportion of oxygen, they exhibit very different
properties; and poffeffed of thefe properties, they are
ranked among the clafs of acids. The fubftances
which poiTefs the following properties are referred to
this clafs.
u. They redden vegetable blue colours (it). Difttnclive
b. They poffefs a peculiar tafte, which is well charaders.
known by the terms acid or four.
c. They combine wuth water in all proportions.
d. They enter into chemical combination with al¬
kalies, with earths, and metallic oxides, and form with
them compounds which have been denominated falls. 4 £.g
3. The acids are a very important clafs of bodies, Importance
and not merely on account of their peculiar properties, of acids,
and the lingular and ufeful compounds which they
form with other fubftances, but alfo as they are the in-
ftruments of analyfis in the hands of the chemift for
difcovering the properties and combinations of the ob-
jefts of his fcience. Without their aid he can fcarce-
ly move a fingle ftep in his inveftigations. It w’as
therefore neceffary to introduce the account of the
acids in this place, that we might be early acquainted
wfith the means of profecuting our refearches. ^
4. Acids w’hich have the fame bafe, combine with Nomenck-
oxygen in different proportions. Thus, for inftance,ture-
fulphur combines with oxygen in two proportions.
The 100 parts of one compound contain 32 of oxy¬
gen, and the too parts of the other contain 38 parts.
The charafteriftic properties of thefe compounds are
totally different. It is therefore neceffary that they
Ihould bfe diftinguilhed byfome appropriate name, and
this accordingly has been attended to in the conftruc-
tion of the prefent chemical nomenclature. The name
of the acid is derived from the bafe, and this name has
a different termination according to the proportion of
the oxygen combined with its bafe. With the fmall-
eft proportion the name terminates in the fyliable ous';
wdth the greater proportion, it terminates in the fylla-
ble ic. Thus, in the cafe of the acid’formed with ful¬
phur, that compound in which there is the fmaller
proportion of oxygen is denominated the fulphurous
acid; the other, which has the greater proportion of
oxygen is the fulphuric acid. In the fame way when
phofphorus combines with oxygen in the fmalleft pro¬
portion which gives it acid properties, it is called the
phofphorous acid; in the greater proportion, the phnf-
phoric acid. And thus by the fimple change of the
termination, the name is defcriptive of the peculiar
ftate of the proportions in the compound.
3 S 2 Sect.
'     * -
(1) Perhaps the combination of oxygen and azote, as they exift in atmofpheric air, Ihould be excepted. It
is to the combination of oxygen in greater proportion with azote than exifts in atmofpheric air, that the name of
oxide is given. But philofophers are not agreed whether atmofpheric air is to be confidered as a chemical com¬
bination, or a mechanical mixture.
( k) Hence vegetable blue infufions, or paper ftmned with them, are employed as lefts to difcover acids.
Thefe are fometimes called re-agents. A great variety of fubftances are employed for this purpofe, fuch as the
infufion and tinfture of litmus, and of tutnfole the fyrup of violets, the infufion of the flowers of mallow or red
cabbage.
J
508
Arids
460
Names.
461
Hiitory.
462
Formation
by experi¬
ment.
4f3
And in the
large way.
464
’ur iiic At ion
4^5
Properties.
466
Action of
heat.
Sect. I. Of Sulphuric 4cid.
1. The name of fulphuric acid is given to the com¬
bination of fulphur and of oxygen, with the greateft
proportion of the latter. It was formerly called vitri¬
olic acid, becaufe it was obtained from vitriol by dif-
tillation, which is a compound of fulphuric acid and
an oxide of iron. When it is ftrongly concentrated,
it has a fluggifh appearance ; hence it was called, 01/
of vitriol. It has alfo been denominated oleum ful-
phuris per campanam, becaufe it was obtained by burn¬
ing fulphur under a glafs bell.
2. The ancients were unacquainted with this acid.
Pliny fpeaks of vitriols, which were ufed for different
purpofes, in fome of which it was probably decompo-
fed. Sulphur was burnt in facrifices, but in neither
cafe was the produft attended to. Bafil Valentine is
the firft who mentions this acid, about the end of the
15th century. Agricola and Paracelfus have alfo
fpoken of it, but Dornaeus is the firft who defcribed it
diftin&ly, in the year 1570.
3. If a quantity of flowers of fulphur be expofed to
a degree of heat fufficient to inflame it, and if, when it
is in a ftate of ignition, it be introduced into -a jar
filled with oxygen gas, it burns with great fplendor,
and emits a great quantity of white fumes. Thefe
fumes may be condenfed, by pouring a fmall quantity
of water into the jar, and when this is examined, it is
found to poffefs acid properties. This is the fulphuric
acid. It is procured, as appears by this experiment,
by burning fulphur in oxygen gas.
4. The procefs for obtaining fulphuric acid in the
large way is the following. A mixture of fulphur and
nitre is burnt in leaden chambers. The ufe of the ni¬
tre is to fupply a quantity of oxygen for the combuf-
tion of the fulphur. There is a little water in the bot¬
tom of the veffels, which ferves to condenfe the va¬
pours given out during the combuftion. The acid
which is obtained in this way is very weak, for it is
diluted with the water in which it was condenfed,
which water maybe feparated by diftillation. Even
after this it is ufually contaminated with a little lead
from the veffels, fome potafh, and fometimes nitric and
fulphurous acids. To obtain it perfe&ly pure, the ful¬
phuric acid of commerce muft be diftilled. This pro¬
cefs is conduced by putting a quantity of the acid in¬
to a retort, and expofing it to a degree of heat fuffi¬
cient to make it boil. The beak of the retort is put
into a receiver, in which the acid, as it comes over, is
condenfed.
5. The acid thus purified, is a tranfparent colour-
kfs liquid, of an oily confiftence. It has no fmell,
but a ftrong acid tafte. It’deftroys all animal and ve¬
getable fubftances. It reddens all vegetable blues. It
always contains water. When this is driven off by a
moderate heat, the acid is faid to be concentrated.
When as much concentrated as poffible, the fpecific
gravity is 2, or double that of water $ but it can rare¬
ly be obtained of greater denfity than 1.84.
6. The fulphuric acid fuffers no change from being
expofed to the light. It boils at the temperature of
546°, or, according to Bergman, 540°. When this
acid is deprived of its caloric, it is fufceptible of con-
CHEMISTRY.
gelation, and even of cryftallization, in flat, fix-fided
prifms, terminating in a fix-fided pyramid. It cryftal-/
Acid!.
lizes moft readily, when it is neither too much con¬
centrated, nor diluted with water. Of the fpecific
gravity of 1.65 it cryftallizes at the temperature of a
few degrees below the freezing point of water. Of
the fpecific gravity of 1.84 it refifts the greateft de¬
gree of cold. Chaptal obferved it cryftallize at the
temperature of 48°, and Mr Keir found that it froze
at 450 of the fpecific gravity of 1.78. 457
7. Sulphuric acid has a ftrong attra&ion for water. Attradls
In fome experiments that have been made, fulphuric ^ater
acid, when expofed to the atmofphere, attrafted above Uons y*
fix times its weight of water. When four parts of
concentrated fuljftiuric acid, and one part of ice at the
temperature of 3 2°, are mixed together, the moment
they come in contaft the ice melts, and the tempera¬
ture rifes to 212°. A greater quantity of caloric is
given out w’hen the two bodies are mixed together in
the liquid ftate. If four parts of the acid and one of
water are fuddenly mixed together, the temperature
of the mixture rifes to about 300°. This extrication
of caloric, it is obvious, arifes from the hidden conden-
fation of the two liquids, the medium bulk of which is
confiderably lefs than the two taken together.
8. So great is the attra&ion of this acid for wrater,
that the ftrongeft that can be prepared can fcarcely be 443
fuppofed to be entirely free from it. It has therefore Method of
greatly occupied the attention of chemical philofophersdelermin-
to determine the proportions of real acid and water,
in fulphuric acid of any given fpecific gravity. This 1
fubjefl has been inveftigated by Wenzel, Wiegleb,
and Bergman, and more lately and fuccefsfuHy by Mr
Kirwan. His method wras the following. Eighty-fix Mr Kir-
grains of potafh, diflblved in water, were faturated with wan’s.
fulphuric acid of a known fpecific gravity. The folution
being turbid, water was added till the fpecific gravity
was 1.03 at temperature 6o°. The whole weight was
now equal to 3694 grains. Forty-five grs. of fulphate
of potafh diffolved in 1017 grs. of diftilled water, had
the fame fpeeific gravity at the temperature 6o°.
Hence the proportion of fait in each folution was
equal. But in the laft, the quantity of fait was
3694 
22.6
then the quantity of fait in the former was
1 ^3-45 grains* Of th*8 quantity only 86 were alkali j
the remainder, therefore, viz. 77.45 grains, were acid,
or acid and water. The quantity of acid employed in
the faturation amounted to 79 grs. ftandard but the
quantity of acid taken up was only 77 45 grs. there¬
fore 1.55 were reje&ed, and confequently were mere
water, therefore the acid taken up is ftronger than
ftandard j and fince 79 parts ftandard lofe 1.55 by
combining with pure potafh. 100 parts ftandard fhould
lofe 1.96, or 98.04 parts of acid of the ftrength of
what is found in fulphate of potafh, contains as much
real acid as too parts ftandard. Hence TOO parts of
this ftrong acid are nearly equivalent to 102 of ftand¬
ard. Therefore, too parts of potafh take up nearly
92 of ftandard fulphuric acid, or 82 of the ftrongeft,
and afford 182 of fulphate of potafh. Mr Kirwan
thinks there is no reafon to fuppofe that the fulphate of
potafh
CHEMISTRY.
Acids. potato contains any water of cryflallization. One
v-—-v 1 hundred grs. expofed to a red heat for half an hour
, fell into powder, and loft only a Angle grain *.
ivZfil0' It having been fuggefted by Guyton-Morveau, Mr
' Kirwan obferves, that the denfities of mixtures of ful-
phuric acid and water being greater than what is found
by calculation, toould be aicribed to the condenfation of
the aqueous part, rather than to that of the acid •, and
this led him to confider of a different method from
what he had formerly employed in determining the
quantity of real acid in fulphuric acid of different den¬
fities. Sulphuric acid of the fpecific gravity of 2.000,
which is the ftrongeft that can be produced by art,
was taken as the ftandard of the ftrength of all other
acids. He could not procure the acid of this ftrength
at the temperature of 6o°. But from many experi¬
ments made with acids of inferior denfity, as 1.8846,
1.8689, 1.8042, 1.7500, he concludes, that the con¬
denfation of equal weights of this ftandard acid and
water amounts to -^th of the whole. Then by apply¬
ing Mr Pouget’s formulas (l) for inveftigating the
increafed denfities of inferior proportions of acid and
water, the fucceffive increments of denfity will be
found as in the following table.
Parts.
(l) The formula here alluded to was invented by M. Pouget in the invefligation of the fpecific gravity of
alcohol mixed with water in different proportions j and he has given a detailed account of his method in a letter
addreffed to Mr Kirwan, which is inferted in the Tranfadlions of the Royal Irito Academy, vol. iii. p. 157*
Having purified alcohol by repeated diftillations, the fpecific gravity at the temperature 65.75° was found
to be 0.8199. This he took for his ftandard. And confidering the fpecific gravity as the means of dif-
covering the increafe of denfity, or the diminution of volume, he thought the quantities in the mixture would
be beft determined, not by the difference of weight, but of volume. He. therefoie took ten mixtures, the
firft containing nine meafures of alcohol and one of water, the fecond eight meafures of alcohol and two
of water, and fo on to the laft, which contained only one meafure of alcohol and nine of water. But as the
real meafures are always uncertain, he weighed them to aicertain the fpecific gravity. Thus x 0,000 grains
of water and 8199 of alcohol formed a mixture of equal parts in bulk. Knowing the real fpecific gravi¬
ties of mixtures of alcohol and water, taking a mean of a great number of obfervations made at the lame
temperature, and comparing them with the fpecific gravities found direftly by calculation, he thus deduces
the increafe of denfity or the diminution . of volume produced in the whole mafs by the mutual penetra¬
tion of the fluids. For calling A the real fpecific gravity, and B the fpecific gravity found by calcula¬
tion, n the number of meafures which compofe the whole mafs, «—x that to which it is reduced by mutual
penetration, it is evident, fince this increafe of denfity does not diminifti the weight of the whole mafs, that
nB = n^x X A. Then *= A~-X », or making «= 1 which expreffes the diminutions of bulk, or the
A.
quantities of fluid abforbed during the mixture. . . . . r i • •
The following table contains the refult of Po-iiget’s experiments, or the diminutions of volume which is
fuppofed to be = I of each of the mixtures, calculated according to the formula.
From this table it appears that the numbers which exprefs the diminution of bulk follow a regular pra-
greflion. The greateft correfpond to the mixtures of equal parts, and they decreafe towards each end of the
Srogreflion. They muft therefore be regulated by feme general law. M. Pouget thinks that the alcohol
may
C H
Parts
Water.
5
10
20
25
3°
35
4°
45
5°
Standard.
95
90
85
80
75
70
65
60
55
50
E M
Increments
of Denfity.
,0252
s°479
,0679
,0856
,0699
,1119
,1279
“ By adding, fays Mr Kirwan, thefe increments to
the fpecific gravities found by calculation, and taking
I S T R Y.
arithmetical mediums for the intermediate quantities of Acids,
ftandard, I made out the firft 50 numbers of the fol-
lowing table ; the remainder was formed by aftual ob-
fervation in the following manner, premifing that the
fpecific gravities were always taken between 59,5° and
6o°, or at moft 60,5° of Fahrenheit.
“ ill, I found by the preceding part of the table
that 100 parts of fulphuric acid whofe fpecific gravity
was 1.8472 contained 88,5 parts ftandard; confequent*
ly 400 grs. of this acid contain 354.
“ zdly, I then took fix portions of this acid, each con¬
taining 400 grs. and added to them as much tvater as
made them contain refpedlively 48. 46. 44. 42. 40. and
38. grains ftandard. To find the proportion of water
that
may be conceived as being difiblved in the water which has abforbed or retained part of it in its pores.
I he quantity abforbed ought to be in the ratio of that of the fol vent and the body diffolved, and each meafure
of water will retain quantities of alcohol proportional to the number of meafures of this fluid in the mixture.
Thus for example, in a mixture formed of nine meafures of alcohol and one of water, this meafure of -water
will abforb a quantity of alcohol =r9 : and in another mixture of eight meafures of alcohol with two of water,
each meafure of wrater will contain a quantity of alcohol =2:8. Confequently the diminutions of bulk of each
mixture are in a ratio compounded of the number of meafures of alcohol and of water which form it; and in
the table above, as 1X9* 2x8, 3X7> 4X6, 5X5>&C» And in general taking for a conftant quantity the
diminution of bulk with equal meafures, and calling it c ; calling the whole number of meafures ti; the number
of meaftlres of alcohol in any mixture, x, and the increafe of denfity or diminution of volume z, we (hall have
n n —  AC   
c; 5$ ; ; - X “ : n—x X # : and k =*--x nx—** : or making «m, 4cx—4c.r*. The increafe of denfity,
calculated according to the formula, correfponds pretty nearly with experiments; for all mixtures in which the
alcohol is in greater quantity than water, but not in thofe cafes in which the W’ater is in greateft proportion,
the real increafe of denfity is much lefs than by calculation, and the differences become more confiderable as
the quantity of water is increafed. M. Pouget thinks, that when the quantity of water is greater than that of
alcohol, the law of abiorption is difturbed ; and he conjedlures that it is owing to the attraftion of the particles
of the wTater among themfelves, which confequently oppofe their union with any other fubftance. But when
the. alcohol forms at leaft the half of the whole mafs, the diminutions of bulk are as the produdls of the numbers
which exprefs the proportions of alcohol and w’ater forming the mixture : they may be reprefented by the formula
__t\cnx—4c«a
55 — —'———• By this formula may be determined the ftrength of fpirits of wdne of commerce, or the
number of parts of wrater and ftandard alcohol of which they are compofed.
The number of meafures of the whole mafs or the bulk
I he number of meafures of alcohol in any mixture
I he diminution of bulk of equal parts by experiment - -  u
I he diminution of bulk of a mixture containing ^ meafures of alcohol by hypothefis rrqc# — 4 c
The fpecific gravity of water - - - = a
Specific gravity of alcohol - „ * ~ fr
Specific gravity of the unknown mixture - - —y
Since the increafe of denfity does not change the weight of the mafs, w'e fhall have
XJ-
— x
1 —x x a bx
= 1—4 cx -\-qc x2 xy-
By this equation may be found the value of x or the proportion of alcohol, having previoufty afcertained the
fpecific gravity of the mixture, and to determine this fpecific gravity, or the value ofby knowing the pro¬
portions of alcohol and water. Hence
x—0.5-
— fc-
a—b fa—y , (a—b \
8cy 4 c j \8 cy
8cy
-a x-\-b x
1—/[.cx-^-qcx3
And making azzi, b:
ro.8199,
xzx-O 5 -
0.1801
+
°-23°44'
0.1801 X
J
1 y
O.ll^Zy
(o-
o.iSot
2304J
-0.5
i—0.1152^4-0.1152**
1
Acids.
Standard
too Parts. Temp. 6o°.
2,000
1,9859
i>97»9
l»9579
i,9439
1,9299
1,9168
1,9041
1,8914
1,8787
1,8660
1,8542
1,8424
1,8306
1,8188
1,8070
100
99
98
97
96
95
94
93
92
91
90
89
88
87
86
85
100 Parts. Standard
too Parts. Standard.
i,79 9
1 7849
i,7738
1,7629
*,75r9
i,74l6
1,73x2
1,7208
1,7104
1,7000
1,6899
1,6800
1,6701
1,6602
x,65°3
1,6407
84
83
82
81
80
79
78
77
76
75
74
73
72
71
70
69
,6312
,6217
,6122
,6027
,5932
,584°
,5748
,5656
,5564
,5473
,5385
,5292
,5202
,5112
,5°22
,4933
68
67
66
65
64
63
62
61
60
59
58
57
5^
55
54
53
C H E M I
that (hould ba added to each portion of acid, in order
J that it {hould contain the given proportion of ftandard,
I ufed the following analogy : Let the quantity of wa¬
ter to be added to 400 parts of the acid that the mix¬
ture may contain 48 per cent, ftandard be x.
Then 400 + *. 354:: 100. 48, then 192004-48*
=35400.
„ . , 16200
And 48*=35400—19200=16200. And '■'v=-^g—
— 337,5* _ _ ...
“ In this manner I found the quantities ot water to
be added to each of the other portions. The mix¬
tures being made, they were fet by for four days,
ftirring them with a glafs rod (that remained in them)
each day, and the 5th day they were tried ; after which
the half of each was taken out and as much water ad¬
ded to them, and then fet by for three days, by which
means the fpecific gravities correfponding to 24. 23.
22. 21. 20. and 19. per cent, ftandard were found, af¬
ter which fix more portions of 400 grs. each of the
concentrated acid, whole fpecific gravity was 1,8393,
■were taken, the proper proportion of water added to
each, and after three days reft and repeated agitation,
their denfities in temperature 6o° were examined as
above, by which means the fpecific gravities correfpond¬
ing to 36. 34. 32. 30. 28. and 26. per cent, ftandard
were obtained, and half thefe portions mixed with half
water exhibited, after three days reft and agitation, the
denfities correfponding to 18. 17. 16- 15. 14. and 13. per
cent, ftandard in the above temperature. The balance
I ufed turned with TV of a grain when charged with
two ounces, and the folid employed was a fmall glafs
ball containing mercury which loft 27,88 grs. of its
weight when weighed in water in temperature 56°,
fufpended commonly by a horie-hair, but when dipped
in ftrong nitrous and marine acids it is fufpended by a
fine gold wire, and then loft 27,78 grs. of its weight
in water.
“ I alfo examined and re&ified, in fome inflances,
many parts of the firft 50 numbers of the table in the
fame manner, but in general I found them juft.
Table of the Quantity of the Standard Sulphuric Acid,
2,000 in Sulphuric Acid of inferior Denftty.
S T R Y.
Table Continued.
Standard
100 Parts. Temp. 6c°.
100 Parts. Standard,
100 Parts. Standard.
1,4844
i,4755
1,4666
i,442 7
1,4189
1,4099
1,401 o
x,3875
I>3741
i,3663
x>3586
i,3473
i,336°
1,3254
I,3I49
1,3102
x,3°56
52
5i
5 3
49
48
47
46
45
44
43
42
41
40
39
S8
37
36
1,2951
1,2847
i,2757
2,2668
1,2589
1,2510
1,2415
1,2320
1,2210
1,2101
1,2009
1,1918
1,1836
IA746
1,1678
1,1614
MJ31
35
34
33
S2
31
3°
29
28
27
26
25
24
23
22
21
20
J9
MSS8
i,i3°9
1,1208
1,1129
1,1011
i,°9i5
18
17
16
15
14
13
1,0896
1,0833
1,0780
1,0725
1,0666
1,0610
1,0555
1,0492
1,0450
1,0396
1,0343
12
11
10
9
8
7
6
5
4
3
2
“ The laft eleven numbers were only found by analo¬
gy, obferving the feries of decrements in the four pre¬
ceding denfities, and therefore are to be confidered
barely as approximations.
“ To reduce vitriolic acids of given denfities, at any
degree of temperature between 490 and 70°, to
which they fhouldhave at temperature 6o°, in order that
their proportion of ftandard may be thereby inveftigat-
ed, I made the following experiments :
Degrees of
Temperature,
70°
65
60
55
5°
49
Sp. Gr. of
A.
I.8292
1,8317
I.8360
1,8382
1,8403
1,8403
Sp. Gr. of
B.
Sp. Gr. of
C.
1,6969
1,6983
1,7005
1,7037
1,7062
1,3845
1,3866
1,3888
1,3898
1,3926
“ Hence we fee that vitriolic acid, whofe denfity at
any degree between 490 and 70° lefernbles or ap¬
proaches the correfponding denfity in the column A,
gains or lofes 0,00126 of its fpecific gravity by every
two degrees between 6o° and 70° of Fahrenheit, and
0,00086 by every two degrees between 490 and 6o°.
^ “ Secondly, That any vitriolic acid, whofe denfity
at any degree between 50° and 70 refemblcs or ap¬
proaches to the correfponding denfity in the column B,
gains or lofes 0,00158 for every two degrees between
6o° and 70° 5 and 0.0017 by every two degrees be¬
tween 50° and 6o°. Whence it appears that the
ftronger acid islefs altered by-variation of temperature
than the weaker, which formerly appeared to me an
irregularity, but now feems to proceed from the in-
creafe of the accrued denfity, when larger. propor¬
tions of water are mixed with the ftronger acid.
“ jdly, Sulphuric acid, whofe denfity at any degree
between 50° and 70° refembles the correfponding at
the fame degree in the column C, gains or lofes 0.00086
for
* Irijh
‘Tranf. vol.
iv. p. 7.
470
Compofi-
tion.
471
Adtion
with hy¬
drogen.
47 2
Charcoal.
100.0
473
Phofphorus,
474
Sulphur.
mg
C H E M I
for every two degrees between 6o° and 70® inclu-
'lively, and 0.00076 between 50° and 6o°. Between
450 and 50° I couid perceive no difference *.
9. Attempts have been made to determine the pro- tance.
portion of oxygen and fulphur, which enter into the
compofition of fulphuric acid. According to the ex¬
periments of Lavoifier, in which he meafured the quan¬
tity of oxygen abforbed, by a given weight of fulphur
during combuftion, the proportions are,
7'i fulphur,
29 oxygen.
100
But other methods have been adopted, which promife
more accurate refults. Thefe are, by decompofing
other fubftances which contain oxygen, by means of
fulphur. According to the experiments of Mr Che-
nevix, conducted in this way, the fulphuric acid con-
fifts of
451.5 fulphur,
38.5 oxygen.
S T R Y.
arts and manufactures. It is employed alfo in me-
dicine and pharmacy; the preparation of it, there¬
fore, has long been an objeCt of conliderable impor-
Acids.
477
17. The affinities of fulphuric acid are the follow-Affinities,
475
Sulphates.
Ufes
476
ro. Sulphuric acid does not combine with oxygen,
nor has it any a£Uon with azotic gas.
11. It appears that hydrogen has a greater affinity
for oxygen, than the fulphur has, and therefore the ful¬
phuric acid is decompofed by means of hydrogen gas.
In the cold there is no aftion between hydrogen gas
and fulphuric acid j but if they are made to pafs
through a red-hot porcelain tube, the acid is decom¬
pofed $ water is formed, and fulphur is precipitated.
When hydrogen gas is employed in a greater propor¬
tion than the half of the acid, the fuperabundant gas
diffolves the fulphur, and is difengaged in the form of
fulphurated hydrogen gas.
12. Charcoal has no aCtion on fulphuric acid in the
cold; but at the boiling temperature, it decompofes it,
and converts it into fulphurous acid. If a piece of
red-hot charcoal be immerfed in a quantity of concen¬
trated fulphuric acid, part of the acid is fuddenly dif-
engaged under the form of thick white fumes, accom¬
panied with fulphurous acid gas. The fulphuric acid
is decompofed ; part of its oxygen is attracted by the
charcoal, forming carbonic acid, and thus it is reduced
to the lowed proportion of oxygen, in the date of ful¬
phurous acid.
13. A fimilar effe£t is produced by phofphorus.
Phofphorus, with the affidance of heat, partially de¬
compofes the fulphuric acid, by abdra&ing part of its
oxygen. Phofphoric acid is formed, and fulphurous
acid driven off.
14. In the cold, fulphur has no adfion on fulphuric
acid ; but, when they are boiled together, the fulphur
is partly diffolved in the acid, and converts it into ful¬
phurous acid. The fulphur which has been added com¬
bines with the oxygen, which is neceffary for the con-
ditution of fulphuric acid, and thus the whole is con¬
verted into fulphurous acid.
15. Sulphuric acid combines with alkalies, the earths
and the metals forming falts ; which, in the prefent
language of chemidry, are denominated fulphates.
16. This acid is employed in great quantity in many
I
Barytes,
Strontites,
Potadi,
Soda,
Lime,
Magnefia,
Ammonia,
Glucina,
Yttria,
Alumina,
Zirconia,
Oxide of Zinc,
Iron,
Manganefe,
Cobalt,
Nickel,
Lead,
Tin,
Copper,
Bifmuth,
Antimony,
Arfenic
Mercury,
Silver,
Gold,
Platina.
Sect. II. Of Sulthvrous Acid.
j . According to the explanation of the nomencla- Nai^es.
ture of the acids, the term fulphurous (hows that this
acid is in its diminiffied date of combination wuth oxy-
gen. It was formerly called fpirit of fulphur, and vo- Hiftory
latlle fulphurous acid. Although the ancients muff
have been acquainted wdth fome of its properties, as it
is formed during the dotv ccmbudion of fulphur, yet
Stahl is the fird chemid who examined it with atten¬
tion. He fuppofed that it was the fulphuric acid com¬
bined with his imaginary principle of phlogidon. Hence
he called it phlogijlicated. fulphuric acid. It was not
till the year 1774 that its nature and compolition were
difcovered by the labours of Priedley and Lavoifier.
Berthollet afterwards invedigated the formation, de-
compofition, combinations, and ufes of this acid. Four-
croy and Vauquelin* alfo have examined many of* Ann.de
its properties, efpecially the faline compounds which Clim. tom.
it forms, fo that now its properties'are well knowm. xxiv.'p. 229.
2. The fulphurouS acid exids in nature in great
abundance, and particularly in the neighbourhood of in n^tul.e>
volcanoes. It is difehgaged from fome lavas in a date of
fufion, and from the foil which is impregnated with ful- 4gr
phur, when a fufficient degree of heat is applied. It was Fatal to ,
by the vapours of fulphurous acid that Pliny the na- Pliny,
turalid was fuffocated in the eruption of Mount Vefuvi-
us, which dedroyed Plerculaneum, in the 79th year be- ,
fore the Chridian aera. ^
3. When fulphur is burnt in the open air, the fumes Formation. ’
that are generated by this dow combudion, are fulphu¬
rous acid. It was in this way that this acid was for¬
merly
C H E M I S T R Y.
PS
Acids.
4*5
A 6bion
with ca¬
loric.
merly obtained. The method of procuring it, which is
now "followed, is to decornpofe the fulphuric acid by
means of any fubftance which deprives it of part of its
oxygen. If one part of mercury and two parts of
concentrated fulphuric acid be expofed to heat in a
glafs retort, the mixture effervefces, and a gas is dif-
engaged, w-hich may be colledled in jars over mercury.
In this procefs the mercury attrafts part of the oxygen
of the fulphuric acid, and leaves behind that portion
^ which contlitutes the fulphurous acid.
In the date 4- Sulphurous acid thus obtained is in the date of
«if gas. gas, and it is an elaftic, invifible and colourlefs fluid,
like common air. It is rather more than double the
s weight of atmofpheric air. Its fpecific gravity is
Properties. 0.00246 *, IOO cubic inches weigh nearly 63 grains. It
has a (harp pungent fmell •, it is unfit for refpiration,
and for fupporting combuftion. It reddens vegetable
blues, and then deftroys the greater number of them. It
is on account of this property that the fumes of fulphur
are employed to remove the (lains of fruit from linen,
and that the fulphurous acid is oiten ufed in bleach-
ing.
5. The fulphurous acid gas reftadls the light ftrong-
ly without undergoing any change. When it is ftrong-
ly heated, as in a red-hot porcelain tube, it remains
unaltered, according to the experiments of Fourcroy.
But Dr Prieftley and Berthollet found that it depofi-
ted fulphur, after long expofure to heat. At the tem¬
perature of—310 it becomes liquid. This property, which
diftinguifhes it from other gafes, and which was difco-
vered by Monge and Clouet, Fourcroy thinks is owing
to the water it holds in folution.
  6. When the fulphurous acid is in the form of gas,
jengas,ic.it does not readily combine with oxygen. In its fluid
form it unites more readily, and is converted into ful¬
phuric acid. In making a mixture of fulphurous acid
gas and oxygen gas pafs through a. red-hot tube, they
combine together, and are converted into fulphuric
acid. There feems to be no aftion between fulphurous
acid and azotic gas.
vvim uv- 7- Hydrogen gas has no a£lion on fulphurous acid gas
drogen gas, ;n the cold ; but when a mixture of thefe gafes is made
to pafs through a red-hot tube, fulphurous acid is de-
compofed •, the hydrogen combines with the oxygen
and forms water, and fulphur is depofited. If the hy¬
drogen gas be in greater proportion than the oxygen
contained in the fulphurous acid, it diflblves part of
the fulphur, and paffes off in the form of fulphurated
hydrogen gas. , „
8. Its adlion with charcoal is fomewhat fimilar. in
the cold there is no effe£t, but expofed together to a
red heat, carbonic acid is formed, by the union of car-
bone and oxygen, and fulphur is depofited.
9. There is no adlion whatever between phofphorus
and fulphurous acid gas •, but phofphorated hydrogen
gas is decompofed by this acid. When the two, gafes
come in contaft, a white thick vapour is produced^
fulphur combined with phofphorus in the folid Hate is
depofited, and water is formed.
4’° 10. Sulphur has no aftion on this acid •, but fulphu-
ed'hydro- rated hydrogen gas, at the inftant it comes in conta£l
with fulphurous acid gas, is condenfed *, folid fulphur
is depofited, and water is formed, wdth the extrica¬
tion of caloric by the condenfation of the tivo gafes.
You V. Part II.
Acids
486
With oxy-
4S7
"With hv-
488
With char¬
coal.
4S9
With phof¬
phorated
gas.
^en gas.
11. Water has a firong attra£lion for fulphurous acid
gas. A bit of ice brought in contadl with it, is im- " “
mediately melted without any perceptible change 0fWl^>^ra-
temperature. When w-ater is faturated with this gas, ter>
it is known by the name of fulphurous acid, or liquid
fu/phurous ctfid. The fpecific gravity is 1.040. At
the temperature of 430 water combines with ^ of its
weight of fulphurous acid gas f ; but as the temperature f Fourcroy,
increafes, it abforbs it in fmaller proportion. It
freezes at a temperature a few’ degrees below 3 2°, and- ^’
it paffes into the folid (late without parting with any
of its acid. The liquid fulphurous acid has the fmell,
tafte, and other properties of the gas, and particularly
that of deftroying vegetable colours. When expofed
to the atmofphere, it gradually abforbs oxygen, and
paffes into the ftate of fulphuric acid. This change
goes on more rapidly when it is diluted with water,
and agitated in contaft with the air. 492
12. The fulphuric acid feparates the fulphurous acid tu^-
in the gafeous form from its combinations, and even l5 unc acl
from water. Concentrated fulphuric acid abforbs this
gas, which imparts to it a yellowiflr brown colour,
and renders it pungent and fuming. The two acids
firongly attrafl each other, fo that when they are ex¬
pofed to the adlion of heat, the firft vapour which rifes
cryftallizes in long, white, needle-fhaped priftns. T. his
is a compound of the two acids. It fmokes in the air;
diffolves with effervefcence in it, and when thrown in-
to w’ater produces a hiding noife, like a red-hot iron. Glacial ful-
It has the ftrong fmell of fulphurous acid. This fub-phuric acid-
ftance was formerly called glacial fulphuric acid*. *
13. Sulphurous acid is very much employed in the*
arts, and fiometimes in medicine. In the ftate of gasufes-
it is ufed for the bleaching of filk and wool, by extract¬
ing the colouring matter. 1*1 removes alfo the ftains
arifing from vegetable juices, and fpots of iron from
linen. _ # 495
14. According to Fourcroy, 100 parts of this acid Compofi-
are compofed of
85 fulphur,
x 5 oxygen.
100
But according to the analyfis of Dr Fhomfon,
68 fulphur,
32 oxygen.
496
Affinities.
15. The compound falts formed by this acid are de¬
nominated fulphites.
16. The following are the affinities of this acid.
Barytes,
Lime,
Potalh,
Soda,
Strontites,
Magnefia,
Ammonia,
Glucina,
Alumina,
Zirconia.
3 T Sect.
5
Acids.
497
Names.
498
Hiftory.
499
Abundant
in nature.
500
Method of
procuring
it.
SO*
Of puri¬
fying.
502
Properties.
5°3
Diibovery
of its com-
pofition.
C H E M
Sect. III. Of Nitric Acid.
1. 'This acid was formerly known by the name of aqua
fortis, and fpirit of nitre. Raymond Lully, who lived
in the 13th century, feems to have been acquainted
with it j and Bafil Valentine, who lived in the 15th,
defcribes the procefs for preparing it. He calls it
water of nitre. But till the difcoveries of modern
chemiftry, little was known of the nature, properties,
and compolition of this acid. It is to the experiments
and refearches of Cavendilh and Prieftley, of Lavoifier
and Berthollet, that we are indebted for the knowledge
we poffefs of this acid.
2. The nitric acid exifts in great abundance in na¬
ture. It is formed by the union of its conftituent
parts, which are evolved during the putrefactive
procefs of animal and vegetable matters j but it is
never found, except in combination with fome bafe,
from which it muft be extracted by art. The com¬
ponent parts of nitric acid, are azote and oxygen.
The name in this cafe is not derived from the bafe,
which is azote, but from nitre, from which it is gene¬
rally obtained. This acid cannot be formed merely by
bringing in contaft the two gafes which are its confti¬
tuent parts •, but if they are mixed together in cer¬
tain proportions, and ele&ric fparks fent through the
mixture, the gafes difappear, and are converted into a
liquid. This is the nitric acid. By a fimilar experi¬
ment Mr Cavendifti difcovered the compofition of this
acid.
3. This acid may be obtained by putting three parts
of nitre or faltpetre with one of fulphuric acid into a
glafs retort, and diftilling with a ftrong heat. The
gas wdiich comes over is condenfed in a glafs receiver,
to which the retort is to be luted. This gas which is
condenfed is the nitric acid. Nitre is compofed of ni¬
tric acid and potafh, but potafti has a ftronger affinity
for fulphuric acid than for nitric acid j it therefore
combines with the fulphuric acid in the retort, and
the nitric acid is difengaged, and paffes over in the
gafeous form.
4. The acid thus obtained is impure, and is conta¬
minated with muriatic, and fometimes wuth fulphurous
acid. It is purified by diftillation with a gentle heat.
At firft too it is of a yellow colour, wffiich is owing to
the fumes of the nitrous gas with which it is combined.
Thefe fumes are driven off by heat, after which the
acid remains pure, and is tranfparent and colour-
lefs.
5. Thus prepared, it has a ftrong acid tafte j a dif-
agreeable pungent odour, and gives a yellow colour
to the fkin. The fpecific gravity of ftrong nitric acid
is 1.583, or, according to Mr Kirwan, at temperature
6o°, 1.554.
6. Nitric acid and one of its compounds, nitre, have
long been the fubjeft of the experiments and refearch¬
es of chemical philofophers. In inveftigating the na¬
ture of nitre, Mayow found that it poffeffed a common
property with atmofpheric air; namely, the property
of giving a red colour to the blood. And, from ob-
ferving that air was deprived of this property by the
procefs of combuftion and refpiration, he drew the lin¬
gular conclufion, that nitre contained that part of the
air which is neceffary for refpiration and combuftion.
I S T R Y.
7. When nitric acid diffolves metallic fubftances, a Acid*,
great quantity of a peculiar gas makes its efcape, and 1
the metal acquires confiderable weight during this pro¬
cefs. According to the phlogiftic theory, it was fup-
pofed that the metal was deprived of its phlogifton, and
that this phlogifton had combined with the nitrous gas
which had efcaped. This was Dr Prieftley’s explana¬
tion. But it was differently explained by Lavoifier.
He took 1x04 grs. of mercury, and added to it 945
grs. of nitric acid. Nitrous gas was emitted during the
folution, and when he expofed the mercury which
had been converted into an oxide, to a red heat, oxy¬
gen gas wras given out, and the mercury appeared in
the metallic ftate. He therefore concluded, that the
nitric acid in this cafe was decompofed, and that it
confifted of oxygen which combined with the metal,
and of nitrous gas which was driven off. The propor¬
tions, he fuppofed, were, 64 parts of nitrous gas by
weight, and 36 of oxygen gas. He found, however,
that the quantity of oxygen obtained in this procefs,
was fometimes greater than what was neceffary to fa-
turate the nitrous gas 5 and he was at a lofs to account
for this quantity. His own experiments, as well as
fome of Dr Prieftley’s, proved, that azote is a compo¬
nent part of nitre.
Mr Cavendifti, wffio difcovered the compofition of
wrater, in his experiments and refearches on that fub-
je£I, found, that nitric acid was produced during the
explofion of oxygen and hydrogen gafes ; and that he
could increafe this quantity by adding azotic gas to the
mixture before combuftion. From this he concluded,
that the formation of the acid depended on the azotic
gas. He proved this by paffing eleftrical fparks
through common air in a glafs tube. The air dimi-
nifhed in bulk, and nitric acid was formed. Repeat- '
ing a fimilar experiment with oxygen and azotic gafes
in certain proportions, he found that the whole could
be converted into nitric acid*. Mr Cavendifti re-* Phil.
peated the fame experiments, with a view to remove ‘Tranf.
fome obje£fions which had been made to his conclu-1?8^*
fions. They were followed by the fame refult, fo that
the faff of the compofition of nitric acid was fully efta-
bliffiedf. _ _ f IbiJ. r 7 8 S,
To perform this experiment, take a glafs tube ofp* 261.
about one-fixth of an inch in diameter. Clofe one end
with a cork, through wffiich let a metallic condudfor
with a ball at each extremity be paffed. Fill the tube
with mercury j immerfe the open end into the mercu¬
rial trough ; introduce a mixture of .13 parts of azotic
gas, and .87 of oxygen gas, occupying three inches of
the tube, and a folution of potafti filling one-half inch
more. Let eledlrical explofions be fent through the
tube till the air ceafes to be diminiffied in bulk. If
the experiment fucceed, the potafti will be found con¬
verted into nitre, which ffiews that the nitric acid,
which is a component part of nitre, has been formed
during the procefs.
8. Nitric acid, having a ftrong affinity for water, is Atflbrbs
never found entirely deprived of this liquid. When water,
expofed to the air, it attradfs moifture from it, and
heat is given out when it is mixed with water. Mr
Kirwran has endeavoured to afcertain the relative 505
ftrength of nitric acid of different denfities, or fpecific IVIetll0d of
gravities ; and the method which he adopted is the <ieternm»-
following. He faturated 36 grs. of carbonate of loda qifantitv
with
C H E M I S T R Y.
Acids.
Urijh
tfranf. vol.
»v. p. 34-
with 147 grs. of nitric acid, of fpecific gravity 1.2754,
which contained 45.7 per cent, of ftandard acid of 1'pe-
cific gravity I.5543- The carbonic acid which efcap-
ed amounted to 14 grs. 5 and by adding 939 grs. of
water, the fpecific gravity of the folution at the tem¬
perature of 58.5°, was 1.0401. By a fimilar tefl with
that employed in afcertaining the ftrength of fulphuric
acid, namely, by comparing this folution with one ot
nitrate of foda of the fame denfity, he found the quan¬
tity of fait amounted to 1 parts. There was an
} 901
excefs of acid of about 2 grs. The whole weight was
1439 grains. The quantity of fait, therefore, was
_143_9_ _ 8e.142 grs. The quantity of pure alkali
16.901
was .50 — 14 =2 36.05 grs. The quantity of ftand¬
ard acid was 66.7 ? the fum of both 22 102.75* .Of
this quantity only 85.142 entered into combination
with the fait; the remaining 17.608 were mere water,
given out by the ftandard acid. If then 66.7 parts
ftandard acid lofe 17.608 parts water combining with
the alkali, 10O parts ftiould lofe 26.38. And, as Mr
Kirwan has made it probable, that nitrate of foda con¬
tains very little water in its compofition ; 100 parts of
ftandard nitric acid is compofed of 73.62 of pure acid,
and 26.38 of water
The following table drawn up by _Mr Kirwan {hews
the quantity of pure acid in nitric acid of different fpe¬
cific gravities.
100 Parts
Sp. Gravity.
i*5543
1.5295
1.5183
1.C070
1*4957
1.4844
1 *47 31
1.4719
1.4707
1.4695
1.4683
1.4671
1.4640
1.4611
1.4582
1*4553
1.4524
1.4471
1.4422
i*4373
1.4324
1.4275
1.4222
Real
Acid.
100 Parts
Sp. (Gravity.
Real
Acid.
73*54
69.86
69.12
68.39
67.65
66.92
66.18
65*45
64.71
63.98-f
63.24
62.51
61.77
61.03
60.30
59* 56
58.83
58.09
57*36
56.62
55.89
55*15
54*I2 +
1.4171
1.4120
1.4069
1.4018
1*3975
■r*3925
i*3875
i*3825
i*3775
1.3721
1.3671
1.3621
1*3571
i*352T
1.3468
i*34i7
1*3364
i.33i5
1.3264
1.3212
1.3160
1.3108
1.3056
53.68
52.94
52.21
5i*47
50.74
50.00
49.27
48*53
47.80
47.06
46.33
45*59
44.86
44.12
43*3 8
42.65
41.91
41.18
40.44
39*7i
38*97
38*34
37*5°
100 Parts
Sp. Gravity.
Real
Acid.
i*30°4
1.2911
1.2812
1.2795
1.2779
36.77
36.03
35*3° +
34*56
33*82
1.2687
1.2586
1.2500
1.2464
1.2419
i*2374
1.2291
1.2209
1.2180
1.2152
1*2033
33*09
32*35
31*62
30.88
3°*i5
29.41
29.68
2 7*94
27.21 +
26.47
25*74+
100 Parts
Sp. Gravity.
Real
Acid.
1.20X5
I.1963
I.1911
1.184 y
1*1779
1.1704
1.1639
1*1581
1.1524
1.1421
1*1319
1.1284
1.1241
1.1165
1.1111
2.1040
25.00
24.26
23*53
22.79
22.06
21.32
20.59
i9*85
19.12
18.48
17*65 +
16.91
16.17
15.44
14.70
13.27
From experiments made by Mr Davy, he has de*
duced the real quantities of nitric acid in folutions of
different fpecific gravities, and by his eftimation the
proportions will appear in the following table *. * Davy's
Refearcbes,-
p. 41.
Table of the quantities of True Nitric Acid in folutions
of different Specific Gravities.
100 Parts Nitric
Acid of fpecific
gravity.
I,504°
1.4475
1,4285
1,3906
i.355i
1,3186
1,3042
1,2831
1,2090
True Acid (m).
9I>55
80,39
71.65
62,96
56,88
52.°3
49.04
46,03
45,°7
Water.
8.45
1961
28 35
37.04
43.i2
47.97
50.96
53.97
54,73
^0$
9. When colourlefs nitric acid is expofed to the Aftion of
light, it undergoes a partial decompofition. Some light,
oxygen g3S is feparated, the acid affumes an orange
yellow colour, and part of it paffes into the ftate of
nitrous acid.
10. It boils at the temperature of 248°, and is en¬
tirely diflipated without alteration, if the heat be con¬
tinued. When it is made to pafs through a red-hot
porcelain tube, it is decompofed, and converted into
its conftituent parts, oxygen and azotic gafes f. When f Fourtroy
T 2 nitric Connaifi.
3 Chim. tom.
ii. p. Si.
( « ) The quantities of oxygen and nitrogen in any folution, may be thus found: Let A_the true acid, X the
oxygen, and Y the nitrogen,
Then X —
238 A
2 so
and Y rr
A
2 so’
| Annul, de
Chim. tom.
xxix.p. 282.
SO?
Of oxygen.
50S
Hydrogen.
5C9
Charcoal.
51°
Phofphorus
and ful-
phur. ,
5”
Of fulohu-
ric acid.
512
Of fnlphu-
rous acid.
5*3
Compofi-
tion.
C H E M I
nitric acid (n) is cooled down to the temperature of
—550, it begins to cryftallize in a few minutes, aflumes
a deep red colour, and congeals into a thick mafs re-
fembling butter, by agitating the veflel which contains
it i*
11. There is no action between nitric acid and oxy¬
gen or azotic gafesj but when concentrated nitric acid
is expofed to the air, the vapour which it exhales com¬
bines with the moidure of the atmofphere, forms white
fumes, and is condenfed into a liquid.
12. Hydrogen gas has no aftion on nitric acid at
the ordinary temperature of the atmofphere 5 but if
they are made to pafs through a red-hot porcelain
tube, there is a violent combuflion with detonation.
Water is formed by the combination of the hydrogen
with the oxygen of the acid } and azotic gas, its other
confiituent part, is evolved.
13. Nitric acid is alfo decompofed by charcoal at a
high temperature. Carbone combines with the oxygen
and forms carbonic acid, while the azotic gas is fet at
liberty.
14. It is alfo decompofed in the fame way by phof¬
phorus and fulphur. When the acid is poured upon
thefe combudibles at a high temperature, inflammation
takes place, and they are converted into phofphoric
and fulphuric acids.
15. When the nitric and fulphuric acids are mixed
together, heat is evolved. The fulphuric acid attra£ls
the wfater which exifled in the nitric acid, and this
w7ater being more condenfed in combination with ful¬
phuric acid, the caloric with which it was combined
along with the nitric acid, is given out. Thus, the
nitric acid becomes more concentrated by the addition
of the fulphuric acid.
When the nitric and fulphurous acids are mixed to¬
gether, a very different aftion takes place. The nitric
acid feparates it from water and its other combina¬
tions •, parts with its oxygen, and thus converts it into
fulphuric acid, and.paffes itfelf into the Hate of nitrous
gas-
16. Accordingto Lavoifier, theproportionsofthecom-
ponents parts of nitric acid are, one part azote and four
parts oxvgen. This was the refult of his experiments
on the decora pofition of nitre by charcoal. According
to Mr Cavendifh, the proportions of the azote and
oxvgen combined by electricity are I part azote and
2.346 of oxygen. The refult of Mr Davy’s experi¬
ments fliew's that too parts of pure nitric acid are
compofed of
29.5 azote,
7:.5 oxygen.
100.0
5T4
Combina¬
tion.
SIS
Affinities.
17. The combinations which are formed with the
nitric acid, and the alkalies, earths, and oxides of me¬
tals, are denominated nitrates.
18. The order of the affinities of nitric acid is the
following :
S T R Y.
Barytes,
Potaffi,
Soda,
Strontites,
Lime,
Magnefia,
Ammonia,
Glucina,
Alumina,
Zirconia,
Oxide of Zinc,
Iron,
Manganefe,
Cobalt,
Nickel, ^
Lead,
Tin,
Copper,
Bifmuth,
Antimony,
Arfenic,
Mercury,
Silver,
Gold,
Platina.
516
19. This is one of the moft important of the acids, Uies.
confidered as an inftrument of analyfis in the hands of
the chemift. It is employed in many arts. It is alfo
ufed in medicine, in difeafes of the fkin •, and it has
lately been exhibited as a cure in venereal affections. In
this cafe, perhaps, it may be regarded as a ufeful aux¬
iliary to the ordinary remedies.
Sect. IV. Of Nitrous New.
1. According to the prefent nomenclature, the n*-of
trous acid fhould bear the fame relation to nitric acid procuring,
that the fulphurous acid bears to the fulphuric 5 that
is, the conflituent parts of the nitric acid ffiould be in
different proportion from thofe of the nitrous acid ;
but this does not appear to be the cafe. What is ufual-
ly denominated nitrous acid, may be formed by com¬
bining nitrous gas with the nitric acid : Or if the lower
ftratum in a veffel of nitric acid be flowly decompofed
by a metallic fubflance, the oxygen of the acid com¬
bines with the metal j nitrous gas is evolved, which
combines with the fuperior ftrata of the nitric acid, and
converts it into nitrous acid f. It has then affumed Fourcroy
yellow colour, and its fpecific gravity is diminiffied. Connaifs.
The fame effeft takes place when the nitric acid is ex- Cbim. tom.
pofed to light. It is deprived of part of its oxygen,
and nitrous gas is evolved, which mixes with the acid,
changes it to a yellow colour, and converts it into ni¬
trous acid.
2. Thus it appears, that nitrous acid is nitric acid Compofi-
combined with nitrous gas. The acid of commerce, t*on
or what is commonly called aqua fortis, is nitrous acid. ^
3. Nitric acid combines in different proportions with ,n different
nitrous proportions
with ni-
      trous gas.
(n) The acid employed in this experiment contained nitrous gas.
CHE M
Ac\$k nitrous ^as, wliich gives rife to many varieties of ni-
 v ' trous acid j and, according to the quantity of nitrous
gas abforbed, the acid exhibits very different colours.
The following table, drawn up by Mr Davy, fhews
in one view the proportions of nitric acid and nitrous
gas, in diiferent coloured nitrous acids.
Table containing Approximations to the quantities of
Nitric Acid, Nitrous Gas, and Water in Nitrous
Acids, of different colours and fpecijic gravities.
ioo Parts.
Sol. nitric acid
Yellow nitrous
bright yellow
Oark orange
Light olive
Dark olive X
Bright green X
Blue green *
of
Specifi
gra.
I 50U
I.50?
l ,500
1,48°
1.4^9
1,478
L47
1 >47 5
Nidic
Acid
Water
N: trous
Gas.
9L55
9° A
88,04
86,84
84,oo
85.4
84 8
84,6
8,45
8-3
8,10
7,6
7 55
7 5
7 44
7 4
1.2
2,96
5,56
6,45
7>l
7,-6
8,00
«;20
Adtion of
light and
heat.
5*1 .
Cornbufti-
bies.
522 _
Sulphuric
acid.
5^3
Compounds,
524
Compoli-
tion un¬
known.
4. Light has no aftion on nitrous acid ; but when
heat is applied, the nitrous gas is driven off, and the
nitric acid remains behind. In the ftate of vapour,
nitrous acid remains unchanged by the adtion of heat.
5. Neither oxygen gas, azotic gas, nor atmofpheric
air, produce any change on nitrous acid.
6. On combuflible bodies the adfion of nitrous acid
is nearly fimilar to that of the nitric acid 5 but many
fubftances are more rapidly inflamed by nitrous acid.
This feems not only to depend on the ftate of the divi-
fion or rarefaction of the nitrous gas combined with the
nitric acid, hut alfo on the nitrous gas itfelf being
more eafily decompofed, and givingup itsoxygen, which
is lefs ftrongly attracted by the azote, on account of
the great proportion of caloric united with it in the
gafeous ftate. It decompofes phofphurated and fulohu-
rated hydrogen gas, and precipitates the phofphorus
and the fulohur.
7. Sulphuric acid combines with the vapour of ni¬
trous acid, and communicates the property of difpofing
the fulphuric acid to cryftallize. It converts fulphu-
rous into fulphuric acid, and, at the fame time, parts
with irs nitrous gas.
8. Nitrous acid enters into combination with the al-
' kalies and earths. The compounds are diftinguiftied
by the name of nitrites. Thefe compounds are not
made by dire£I combination, and therefore the affini¬
ties of this acid are little known.
Sect, V. Of Muriatic Acid.
1. The component parts of this acid are unknown.-
No attempt which has hitherto been made to difeover
523
I S T R Y.
its conftitjjent parts, has yet fucceeded. But, as it re-
fembles the other acids, the compofition of which has
been difeovered, in many of its properties and combi¬
nations, it is ufually arranged among this clafs of bo¬
dies. The name of muriatic acid is derived from the Names.
Latin word muria, which fignifies fea-falt, or common
fair, from which it is ufually extracted. It was for¬
merly denominated fpirit of fait, acid of fait, and ma¬
rine acid. . r2iS
2. Muriatic acid may be obtained by putting too Method of
parts of dry common fait, and 35 parts of fulphuric procuring,
acid, into a retort or matrafs with a bent tube. The
beak of the retort at the' end of the tube muft commu¬
nicate with a receiver in which there is water, that the
muriatic acid may be condenfed as it paffes into the
receiver. In this way liquid muriatic acid may be ob¬
tained. ^27
3. But if the gas which comes over is received in a In the ftattr
jar inverted in the mercurial apparatus, its properties gas*
may be examined in the ftate of gas. When it firft
paffes over, it is in the form of white fmcke. ^2S
4. Muriatic acid gas poffeffes the phyfical proper-Properties-,
ties of common air. It is an invifible elaftic flu,d. It
has a ftrong acid tafte, and a very pungent fmell. The
fpecific gravity, according to Kirwan, is 0.002315.
5. It is unfit for refpiration, and equally to tor fup-
potting combuftion. ^2g
6. This gas has a ftrong attraction for water. If a Adlion of
little wrater be introduced into a jar filled with this water,
gas, Handing over mercury, the whole of the gas will
be abforbed, and the mercury will’inftantfmeoufly rife
to the top. Or if a jar filled with muriatic acid gas
be inverted into a veffel of water, coloured with vege¬
table blue, the water fuddenly nifties into the jar,
which it completely fills, and the blue colour is chan¬
ged to red, exhibiting the ufual effeCt of acids on ve¬
getable colours. 530
7. Light has no affion whatever on this gas, nor Light and
does it undergo any change when it is made to pafs'ieat'
through a red hot porcelain tube. In the ftate of gasj
it has no aftion upon oxygen gas. When this gas
comes in contaft with atmofpheric air, thick white
fumes are produced, with the extrication of caloric;
This is a combination of the gas with the water in the
atmofphere, by which they are mutually condenfed.
8. There is no aftion between muriatic acid gas
and azote, hydrogen, charcoal, phofphorus, or ful-
phur. _ ... e-j
9. The quantity of water which muriatic acid ab-combines
forbs is very confiderable. Ten grs. of water com-with water
bine with ten grs. of the gas. The liquid acid thusIn great
formed occupies the fpace of 13‘3 Srs' anc^ hence itsT1°!,ortloru
fpecific gravity is 1.500 ; and the fpecific gravity of
the pureft muriatic acid in its condenfed ftate is
3 300(0>>- . . .
The fpecific gravity of the ftrongeft muriatic acid
that can eafily be procured and preferved, is 1.196.
One-
* “ The blue green acid is not homogeneal in its compofition . it is compofed of the blue green fpherules and
the bright green acid. The blue green fpherules are of greater«fpecific gravity than the dark green acid, pro¬
bably bec.aufe they contain little or no water.
+ “ The compofition of the acids thus marked, is given from calculations. . . .
(o) “ Let D = the denfity of a mixture > m the weight of the denfer ingredient; d its denfity-j / the weighty
5iS CHE M
Acids. One Hundred parts of this, Mr Kirwan calculates,
wiH contain about 49 of acid, whofe fpecific gravity
is 1.500, which he calls the ftandard acid. By mix¬
ing this acid with different proportions of water, he
obtained the refults from which he conftru&ed the fol¬
lowing table.
Tabie of the quantity of Real Acid in IOO parts of
Muriatic Acid of different Specific Gravities, at the
Temperature 60°.
100 Parts
Sp. Gravity.
Real
Acid.
too Parts
Sp. Gravity
Real
Acid.
1.196
I.19I
I.187
I.183
i-i79
i-i75
1.171
1.167
1.163
1.155
1151
1147
1.1414
1.1396
1.1358
1.1320
25.28
24.76
24.25
23-73
23.22
22.70
22.18
21.67
21.15
20.64
20.12
19.60
19.09
18.57
i8.c6
17-54
17.02
1.1282
1.1244
1.1206
1.1168
1.1120
1.1078
1.1036
1.0984
1.0942
1.0910
1.0868
1.0826
1.0784
x.0742
i.0630
I-°345
1.0169
16.51
15.99
15.48
14.96
14.44
I3-93
I3,41
12.90
12.38
11.86
I»-35
10.83
10.32
9.80
8.25
5.16
2.58
532
Properties.
Aftion of
light and
heat.
Of fulphu-
ric acid.
Of nitric
acid.
10. The liquid muriatic acid, in its ordinary ftate,
is of a pale yellow colour ; but when it is pure, it is
tranfparent and colourlefs.
11. Light has no action whatever on muriatic acid.
When heat is applied, it readily affumes the gafeous
form. Neither oxygen nor azotic gafes are abforbed
by muriatic acid, nor has this acid any aftion on hy¬
drogen, charcoal, phofphorus, or fulphur.
12. The fulphuric acid feparates the muriatic acid
from its compounds, and even from its combination
with water -, but the muriatic acid drives oflf the ful-
phurous acid from this liquid.
13. One of the moft remarkable charafters of the
muriatic acid, is its combination with the nitric acid.
When thefe two acids are mixed together, they aft
upon each other, are ftrongly heated, and produce ef-
fervefcence, with a change of colour to an orange red.
A mixed acid is thus formed, which poffeffes proper¬
ties which exifted neither in the one acid nor the other
when in a ftate of reparation. It was formerly called
1 S T R Y.
aqua regia, from its property of diflblving gold, which Acid?,
was diftinguiflied by the name asking of the metals. It 1 "n ^
is now denominated nitro-muriatic acid. This acid i-s ^jt^6rnu
not to be confidered as a Ample mixture of the two n^t|°
acids. A double attraftion takes place in their mu¬
tual aftion ; the muriatic acid attrafts part of the
oxygen of the nitric acid, and the nitric combines
with the nitrous gas. The muriatic acid thus com¬
bined with a portion of oxygen, is difengaged with
effervefcence in yellow fumes: the undecompofed ni¬
tric acid feizes the nitrous gas which is formed, and
when it is faturated with it, the aftion ceafes. Hence
arifes the colour of the mixed acid. The peculiar ef-
feft of the nitro-muriatic acid on metallic fubftances,
will be defcribed in treating of the metals.
14. In analyfing a mineral water, Mr Lambe con'Snppifed
eluded, from fome appearances which prefented them- formation
felves during his experiments, that the muriatic acid of muriatic
was formed or generated \ for when iron was afted aC1^-
upon by fulphurated hydrogen gas, oxymuriate of iron
Was formed. He digefted iron filings, previoufly pu¬
rified, in a folution of fulphurated hydrogen gas, in
diftilled water. A bottle was filled with the folution,
and corked. The iron was prefently afted upon 5
air w-as extricated, probably hydrogen gas, which
drove the cork out of the bottle. The liquor, grad¬
ually loft its odour, and at the end of fome days
it had a fmell refembling that of ftagnant rain water.
As the bubbles ceafed to be produced, it recovered its
tranfparency : A fmall quantity of this folution evapo¬
rated to drynefs, left behind a bitter, deliquefeent fait.
Sulphuric acid dropt on this fait, and paper moiftened
with ammonia, held over the glafs, produced vapours,
fo that fome volatile acid was feparated. Eight ounce
meafures of the fame liquor were evaporated, and a
little fulphuric acid was dropt on the refiduum. A
ftrong effervefcence was excited, and acid fumes arofe,
which, from their fmell, w7ere readily knoum to be
muriatic acid. Paper moiftened with water rendered
the vapours vifible in the form of a gray fmoke, which
is the diftinguifhing charafteriftic of muriatic acid.
The fame appearances were exhibited with the fame
refult, when manganefe and mercury wrere diflblved in
fulphurated hydrogen gas *. * Mancb.
The fame experiments have been repeated ; but no Mem. vol.
traces of muriatic acid, in any of the compounds that x. p. 154.
w'ere formed, could be found. In an experiment by
Berthollet, indeed, iron filings w-aftied with water
which gave no marks of containing muriatic acid,
wrhen they were expofed fome days to the air, and
again w^aftied, exhibited fome traces of it -, fo that the
acid itfelf, or its elements, muft have come from the
air or the iron.
15. The
of an equal bulk of water 5 and m', d', and l the fame elements of the rarer : Then D t^le ahove
cafe, zz 20, and /-j-/'rz 13.3. Then I) ~ 2? — 1.5. Now to find the fpecific gravity of the con-
denfed muriatic acid gas, we have from the above equation l — — ^ = 3*3 1 an(l </ = -y =
D
i-5
10
IT
3.03. Kir wan. Iriff TranfaBions, vol. iv. p. 5.
1
CHEMISTRY.
54° ,
Compounds
541
Affinities.
Acids. 15. The bulk of muriatic acid gas is greatly dimi-
jdflied by the aftion of ele&ricity, and hydrogen gas
53s is given out j but this action is limited. Mr Henry
Action of jias that it is not owing to the decompofition of
ee ncitj. acj(j) as might at fitll fight be fuppofed, but to
the decompofition of water which it holds in folution ;
fo that the aftion continues as long as there is any
moilfure in the gas. The oxygen of the water com¬
bines with the acid, and forms oxymuriatic acid $
while the hydrogen of the water is evolved.
Ufes'in de- I^* Muriatic acid gas has been fuccefsfully employ-
ftroying ed in deftroying noxious, putrid exhalations. It was
noxious va-applied in this way in the year 1773 by Morveau, in
pours. purifying the cathedral of Dijon from thefe exhala¬
tions, on account of which it had been altogether de-
ferted. He put fix pounds of common fait into a glafs
veflel, placed in the middle of the church, poured two
pounds of fulphuric acid on the fait, placed the vefiel
on fome live coals, and immediately Ihut the doors.
It was allowed to remain 12 hours ; after which the
doors were opened. A current of air was allowed to
pafs through it $ when the noxious vapours were found
to be deftroyed.
17. The compounds which are formed by the muria¬
tic aid, with alkalies, earths, and metallic oxides, are
diftinguifhed by the name of muriates.
18. The following is the order of the affinities of
this acid.
Barytes,
Potafh,
Strontites,
Lime,
Ammonia.
Magnefia,
Glucina,
Alumina,
Metallic oxides.
Sect. VI. Of Oxymuriatic Acid.
Hiftoiy. 1 • The oxymuriatic acid was difcovered by Scheele
in the year 1774, and he gave it the name of dephlcgi-
Jlicated marine acid. On account of its fingular pro¬
perties, and the important ufes to which it was foon
applied, it has been much examined by chemical philo-
... fophers.
Method of 2. This acid is obtained by the following procefs :
procuring. Take three parts of common fait, and one part of the
black oxide of manganefe reduced to powder. Intro¬
duce them into a tubulated retort 5 place the retort in
a fand bath, and immerfe its beak under the furface of
the water in the pneumatic trough. Pour upon it two
parts of fulphuric acid a little diluted with water. An
eftervefcence takes place, and a yellow coloured gas is
evolved, which may be received in jars, or preferved in
large veflels with ground Hoppers.
The nature of this procefs is fufficiently obvious.
Common fait is compofed of the muriatic acid and fo-
da ; the affinity of the fulphuric acid for foda is ftronger
than that of the muriatic acid ; it therefore combines
with the foda, and the muriatic acid is difengaged in
the ftate of gas. The black oxide of manganefe is
compofed of oxygen and the metallic fubftance. The
fulphuric acid combines with the manganefe, and fets
the oxygen at liberty in the Hate of gas. But there is
alfo an affinity between the muriatic acid and oxygen,
fo that in the moment of evolution they unite, and pafs
off in the ftate of oxymuriatic acid gas.
3. This gas is of a yellowifh green colour, has a ftrong Properties,
penetrating odour, and excites violent coughing, when a
mixture of it with atmofpheric air is refpired j but the
pure gas is totally unfit for refpiration. This gasfupports
combufticn. It diminifties and reddens the flame of a
taper 5 a great deal of fmoke is evolved, and the taper
confumes very rapidly. 545
4. Neither light nor heat have any affion on the gas. and
When paffed through red-hot porcelain tubes, it re-heat,
mains unchanged. ^
5. It has no a61ion whatever on oxygen or azotic 0f
gaffes. hydrogen
6. In the cold no effeft is produced from a mixture gas*
of this gas with hydrogen gas ; but when they are
paffed through a red-hot tube, there is a violent deto¬
nation. 547
7. In the cold there is no action between charcoal Of char-,
and this gas. Wrhen a mixture of equal bulks of this coa1’
gas and carbonated hydrogen gas is fet fire to, there
is only a combuftion of the hydrogen gas, with a de-
pofition of charcoal. If two meafures of oxymuriatic
acid gas, and one meafure of carbonated hydrogen gas
are mixed together in a clofe phial, and allowed to re¬
main for 24 hours, they decompofe each other. Wa¬
ter, muriatic acid, carbonic acid, and gafeous oxide of
carbone, are the produ&s. When water is admitted,
the whole will be nearly abforbed. 548
8. A bit of dried phofphorus introduced into this gas, Ofphofpho-
is inftantly inflamed, and converted into phofphoricrus*
acid. It alfo fets fire to phofphorated hydrogen gas,
which has loft the property of fpontaneous inflamma¬
tion in the air. 549
9. Melted fulphur, plunged into this gas, is imme-0f ll,lPhur'
diatelyinflamed, and converted into fulphuric acid. Sul¬
phurated hygrogen gas is decompofed, but without in¬
flammation, and fulphur is depofited.
10. There is no aftion between this gas and ful-Sulphurous
phuric acid ; but, when fulphurous acid gas is mixed acid,
with it a thick, white vapour is formed, which is the
fulphurous acid converted into fulphuric acid, by de¬
priving the oxymuriatic acid gas of its oxygen. It
has no effeft on nitric acid ; but nitrous gas brought into
contaft with it, is reddened, and converted into nitrous
acid. 55^
ir. What is commonly known by the name of oxy-
muriatic acid, is water faturated with this gas. It has^
a pale green colour, and exhales the fame odour as the
gas. According to Berthollet, a cubic inch of water
abforbs grS. French of the gas. The quantity ab¬
forbed by the water is in proportion to the temperature
and the preffure. When veffels containing water, and
receiving this gas, are furrounded with ice, while the
water is faturated, the gas cryftallizes at the furface,
and even at the bottom of the liquid, in the form of
fix-fided plates, of a greenilh white colour ; but the
flighteft heat diffolves them, and they rife through the
liquor in the form of gas.
Water faturated with this gas at the temperature of
430 has the fpecific gravity of 1.003. 553
12. This acid does not redden vegetable blues, like Deftroys
the other acids. It has the fingular property of de-veSetable
ftroying vegetable colours, on account of which it hasco our’'
been
553 ,
Action of
.light.
•554
Cornpofi-
rtion.
CHE M
been tnucb employed In tbe art of bleaching. The
effect which takes place in this procefs, is the combi¬
nation of the colouring matter with the oxygen of the
acid *, for the acid which has been employed is de¬
prived of its oxygen, and converted into muriatic acid.
But for the full account of this procefs, fee Bleach¬
ing.
13. When this acid is expofed to the light, it is de-
compofed.j it gives out its oxygen gas, becomes colour-
lefs, and paffes into the ftate of muriatic acid. But
when heat is applied, the acid is difengaged in the
ftate of gas, without any perceptible feparation of its
oxygen. Expofed to the air, the acid is gradually le-
parated, exhaling, at the fame time, its pungent, difa-
greeable odour.
14. The conftituent parts of oxymuriatic acid, ac¬
cording to Berthollet, are
89 muriatic acid,
11 oxygen.
I S T R Y.
But, according to the" experiments of Mr Chenevix,
it is compofed of
84 muriatic acid,
16 oxygen.
100
Sect. VII. Of Hyper-oxymvriatic Acid.
■ 555
Nature.
65 oxygen,
35 muriatic acid.
100
Acids.
55s,
Compou-
tiou.
But its properties will be more fully detailed in confi-
dering its combination with potafh, when we come to
treat of that fubftance.
3. The order of the affinities of hyper-oxymuriatic Affinities,
acid, is the following, as they have been afcertained by
Mr Chenevix *.
559
l. Oxygen combines in a different proportion with
muriatic acid, and forms another acid, poffeffed of pro¬
perties which are quite diftinft from the properties of
the laft defcribed. This acid has never been obtained
in a feparate ftate, but the peculiarity of its nature
has been fufficiently demonftrated, in its combinations
wdth other fubftances. As it contains a greater pro¬
portion of oxygen than the oxymuriatic acid, it has
been denominated hyper-oxymuriatic acid.
Hem ob- 2. It may be procured in combination wdth potaffi
,tained. by the following procefs. If a quantity of potaffi,
with fix times its weight of water, be put into one of
the bottles of Woulfe’s apparatus, and a ftream of oxy¬
muriatic acid gas be paffed through it till the potaffi
is faturated, cryftals in the form of fine white feales fall
to the bottom. Thefe are cryftals of hyper-oxymuriate
of potaffi, compofed of potaffi and of hyper-oxymuri-
atic acid. The liquid in which thefe falls have been
formed being evaporated to drynefs, yields another fait
.f, 557 ^ ■which is compofed of muriatic acid and potafh. This
the piocefs. was t^ie difeovery of Berthollet ; and the theory which
he propofed to account for the produfts that appeared
in this procefs was the following. He fuppofed that
the oxymuriatic acid was decompofed : part of it be¬
ing deprived of its oxygen, combined in the ftate of
muriatic acid with part of the potaffi, forming the fait
which wTas obtained by evaporation, namely, the muri¬
ate of potaffi 5 and part united with an additional por¬
tion of oxygen combined with another portion of the
potafh, and formed the fait which was depofited in the
liquid. This theory has been confirmed by the expe¬
riments of Mr Chenevix. According to thefe experi¬
ments the hyper-oxymuriatic acid is compofed of
Potafh,
Soda,
Barytes
Strontites
Lime,
Ammonia,
Magnefia,
Alumina.
Sect. VIII. Of Fluoric Acim.
* PM.
Pranf.
1802.
p. 126.
t. The component parts of this acid are unknown,
It w7as difeovered by Scheele in 1771, and by him and
Prieftley its peculiar properties, which have been con¬
firmed by the experiments of other chemifts, w’ere firfl:
detedled. Margraaff, three years before, had afcertained
that the floor fpar, from which this acid is obtained,
differed in its properties from other fpars. When he
diftilled equal parts of fulphuric acid and floor fpar,
he obtained a w hite fublimate, and found that the glais
retort which he employed in the procefs was greatly
corroded, and pierced with holes. Scheele afterwards
proved by his experiments, that the fluor fpar is com¬
pofed of lime and the peculiar acid to which the name
fluoric has been given.
2. To procure fluoric acid, put one ounce of fiuor Method of
fpar.(fluate of lime) reduced to powder into a retort of?btainin£
tin or lead, pour over it three ounces of concentrated ^
fulphuric acid, and adapt to the retort a tube and re¬
ceiver of the fame metal. When the acid comes in
contaff with the fpar a gas is driven off, which is the
fluoric acid. Toward the end of the procefs, if a gentle
heat be applied, a greater quantity of the acid may
be obtained. If water has been previoufly introduced
into the receiver, the gas is abforbed by it, and the
acid may then be exhibited in the liquid ftate.
3. The fluoric acid appears under two forms, that of Properties
gas and that of a liquid. of tins gas.
The fluoric acid gas has the common properties of
air. It is invifible and elaftic. Its fpecific gravity
has not been accurately determined, but it is heavier
than atmofpheric air. Expofed to the air it combines in-
ftantly with the moifture of the atmofphere, and ap¬
pears in the form of vapour or white fumes. Like
muriatic acid, it has a penetrating pungent fmell. It
reddens vegetable blues, and corrodes the fkin. It is
totally unfit for refpiration. Animals who breathe it
are inftantly deftroyed. It is alfo unfit for the fupport
of combuftion. But before the flame of a candle in¬
troduced into this gas is extinguifhed, it affumes a
greenifti colour. The moft remarkable property of
this gas is that of corroding glafs, in confequence of
its ftrong affinity for the filex one of the component
parts
2
Acids.
Combines
with water.
"5^4 j
Compounds.
S6$.
Affinities.
565
Difcovery.
S67
Prepara¬
tion.
5 (S3
Properties.
C H E M
parts of glafs. This is the reafon that it muft be pre¬
pared in metallic veffels. And even with this precau¬
tion, it is leldom entirely free from this earth, which
it probably derives from the fluor fpar, from which it
is obtained.
4. Light and caloric have no effeft on it. Its pro¬
perties undergo no alteration, even when it has paffed
through a red-hot porcelain tube.
In contaft with oxygenous gas or atmofpheric air,
no change takes place on Huoric acid gas ; nor has
it any adion on azote, hydrogen, carbone, phofphorus,
or fulphur. The other acids, it has been obferved, are
decompofedby oneor other of thefe combuftibles; and in
this way their conftituent parts have been detefted.
We are not however to conclude from thence, that the
fluoric acid is a Ample fubftance. On the contrary, it
wrould be more analogous to other fafts, to draw the
conclufion, that it is a compound, fimilar to the other
acids, whole bafes have been difcovered, and that the
bafe, whatever that may be, has fo llrong an attra&ion
for oxygen as to be unfufceptible of decompofition by
the adtion of any fubftances yet known.
y. When this gas comes in contadl with water it is
rapidly abforbed, and in confiderable proportion. In
this ft ate it is called fluoric acid. The fpecific gravity
of this acid is greater than that of water. By heat the
gas is almoft entirely expelled from the water ; and
w hen it is cooled down to the temperature 230 it freezes.
6. The compounds with the alkalies, earths, and me¬
tallic oxides, are called fluates.
7. The order of its affinities is the following:
Lime,
Barytes,
Strontites,
Magnefia,
Potafli,
Soda,
Ammonia,
Glucina.
Alumina,
Zirconia,
Silica.
Sect. IX. Of Boracic Acid.
1. The component parts of boracic acid are unknown.
It was firft difcovered by Homberg in 1702> who gave
it the name of narcotic or fedative fait. The fubftance
called borax of the Ihops is a compound of this acid and
foda.
2. The procefs for obtaining this acid is the follow¬
ing : Difiblve a quantity of this fubftance in hot wa¬
ter, and filter the folution. Gradually pour on it ful-
phuric acid, till the liquor acquires a flight degree
of acidity. The fulphuric acid combines wdth the
foda j and the boracic acid, as the folution cools, is preci¬
pitated in fmall, fliining white fcales. To purify the acid
thus obtained, it is to be wafhed with cold water, which
removes the more foluble falls with which it is mixed.
3. The boracic acid is in the form of lilvery white
hexagonal fcales, which have a greafy feel, and fome re-
femblance to fpermaceti. It has a fouriffi tafte, which af¬
terwards gives the fenfation of coolnefs. It has no fmell.
It changes vegetable blues to red. In the fcaly form, the
fpecific gravity is 1.479, but when it is fufed, it is 1.803.
Vo t. V. Part II.
I S T R Y. 521
4. When expofed to heat, it froths up, which is Acids,
owing to the feparation of the water of cryftallization, /
and affumes the form of a vifcid pafte. In this ftate it is A(<^0^
known by the name of calcined borax. When it is heat,
expofed to a red heat, it is converted into a hard, tranf-
parent glafs, which, without attradlirig moifture from
the air, becomes opaque when expofed to it, but it re¬
mains unchanged 3 for when it is re-difiblved in warm
water, it refumes its former properties, by cooling
and cryftallization *. # Fmrcr-y
5. Boracic acid has very little attraction for water, Connaift.
boiling water only diffolves about a 50th part of itstom-
weight, and cold water much lefs. When the folution p‘
in water is evaporated in clofe veffels, part of the acid of water,
rifes in the ftate of vapour along with the water, and
cryftallizes in the receiver j but when the whole of the
water is diffipated, the procefs flops 3 fo that it is only
by means of it that the acid is volatilized 3 otherwife
it is perfeCUy fixed. The folution in water has little
tafte, but it reddens the tinCfure of turnfole.
6. Neither oxygen, azotic, nor hydrogen gafes, pro¬
duce any effeCt upon it ; and with charcoal, phofphorus,
and fulphur, it alfo remains unchanged. When burnt
with phofphorus, indeed, there is left behind an earthy,
yellow matter.
7. At a red heat it drives off fome of the acids from On acids,
their combinations, even thofe acids which have the
ftronger affinity for the fame fubftances in the cold.
Boracic acid has fome peculiar aCtion with the fulphu¬
ric, the nitric, and oxymuriatic acids 3 for when it is
heated with thefe acids, it deprives them of a portion
of their oxygen 3 but the changes which take place by
this aCfion have not been diftinClly afcertained f. f/A/.p.i 27.
8. Fabroni of Florence confiders this acid as a modi¬
fication of the muriatic, and he fuppofes that it may be
entirely formed with this acid. The boracic acid, he
farther fuppofes, is probably produced by this modifica¬
tion of the muriatic acid in the water of the lakes of Tuf-
cany 3 but the fafts on which this opinion is founded,
have not been publiffied \Ibid.y.izl.
9. The boracic acid is employed in chemiftry not SI1
direftly as an inftrument of analyfis, becaufe its affinities U es‘
and a£lion have little energy compared with other acids,
but to difcover its peculiar combinations and com¬
pounds. It is alfo employed in the arts, as in foldering,
to affift the fufion of metallic fubftances. It is of
great importance to the mineralogift, in promoting the
fufion of fubftances under the blow-pipe. .573
10. The compounds which boracic acid forms with ^omPoun^s'
the alkalies, earths, and metallic oxides, are diftinguifh-
ed by the name of borates.
11. The affinities of boracic acid are the following: Affinities.
Lime,
Barytes,
Strontites.,
Magnefia,
Potaffi,
Soda,
Ammonia,
Glucina,
Alumina,
Zirconia,
Water,
Alcohol.
3 U Sect.
575
Formation.
. SI6
Hiftory.
577
Prepara¬
tion.
57s .
Properties.
579
Attradls
r.joifture.
CHEMISTRY.
Sect. X. Of Phosphoric Acid.
Acids.
5S0
Adtion of
charcoal.
X, When phofphorus undergoes combuftion in oxy¬
gen gas, a great quantity of white fumes are produ¬
ced, which are depofited in white flakes. Thefe are
phofphoric acid 5 fo that it is a compound of phofpho¬
rus and oxygen.
2. The phofphoric acid was firft fhown to be diftinft
from ail other acids, in the year 1743, by Margraaff.
He found that it exifted in the falls which were taken
from human urine, and that phofphorus could only be
obtained from this acid; as vrell as that it could be
converted into phofphoric acid. This acid was found to
exift in fome vegetable fubftances, although it was for¬
merly fuppofed to be peculiar to animal matters. It
was difcovered by Scheele and Gahn in bones, in the
year 1772. Bergman, Prouft, and Tenant, detefted
it in feveral foflils, and Lavoifier proved by a feries of
accurate and ingenious experiments, that it was com-
pofed of phofphorus and oxygen.
3. Phofphoric acid may be obtained, not only by the
method juft mentioned, but alfo by tranfmitting a cur¬
rent of oxygen gas through phofphorus melted under
water. The acid as it is formed, combines with the
water, from which it may be obtained in a ftate of
purity by evaporation. It may be procured alfo by
dropping fmall bits of phofphorus into nitric acid mo¬
derately heated. An effervefcence takes place, and ni¬
trous gas is evolved. Phofphorus combines with the oxy¬
gen, and forms phofphoric acid. The precaution of
adding but a little phofphorus at a time, and of apply¬
ing a moderate heat to the acid, thould be carefully
obferved. The liquid is then evaporated, and the
phofphoric acid remains behind in the folid ftate. The
water that may be combined with it is driven off, by
expofing it to a red heat.
4. In this ftate phofphoric acid is a tranfparent, co-
lourlefs, folid fubftance, refembling glafs, known under
the name oiphofphoric glafs.
The fpecific gravity of this acid varies, according
to the different ftates in which it exifts. In the li¬
quid ftate it is 1.417 in the dry ftate it is 2.697 ; in
the ftate of glafs 2.8516. It changes the colour of
vegetable blues to red ; has no fmell, but a very acid
tafte.
5. When it is expofed to the air, it attra&s moif-
ture, and is converted into a thick vifcid fluid, like oil.
It is very foluble in water. When in the form of dry
flakes, it diffolves in a fmall quantity of this liquid,
producing a hifling noife like that of a red-hot iron
plunged into water, with the extrication of a great
quantity of heat. In the ftate of glafs it diffolves
more flowly, but the concentrated liquid phofphoric
acid unites with water with very little difehgagement
of caloric.
6. Phofphoric acid being fully faturated with oxy¬
gen, has no a&ion whatever on oxygen gas *, nor is
there any aflion between hydrogen or azotic gafes,
or fulphur, with the phofphoric acid. Charcoal has
no effeft on phofphoric acid in the cold ; but when
they are expofed together to a red heat, the phofpho¬
ric acid is decompofed ; the oxygen combines wdth
the carbone of the charcoal, forming carbonic acid,
and the phofphorus is fet at liberty. This is the pro- i
cefs already defcribed in treating of phofphorus, which
is generally employed for obtaining that fubftance. . 5S1
7. The fulphuric has no a (Elion on the phofphoric Of acids.
acid ; but when the two acids are mixed together in
the liquid ftate, the fulphuric acid, on account of ks
ftrong affinity for water, combines with the water in
the phofphoric acid j and if heat be applied, the ful¬
phuric acid is diffipated, and the phofphoric acid re¬
mains behind in the ftate of a tranfparent vifcid mat¬
ter, or in that of glafs. The fulphurous acid is fepa-
rated from its combinations by the phofphoric acid.
The nitric acid feparates the phofphoric from its com¬
binations. The muriatic acid has the fame effeft. 582
8. The component parts of this acid have been ac-^^P01'
curately afcertained by Lavoifier, and it confifts of,
60 oxygen,
40 phofphorus.
100
583
9. The accuracy of our information with regard to Importance
the component parts and properties of phofphoric acid,
renders it of great importance in many chemical opera¬
tions j and if it could be obtained with lefs difficulty
and expence, its ufes might be extended to medicine
and the arts. 5S4
10. It combines with the alkalies, earths, and me-Compounds,
tallic oxides, and forms falls which are denominated
phofphates. _ _ _ 58 5.
ix. The following is the order of its affinities. Affinities.
Barytes,
Strontites,
Lime,
Potaffi,
Soda,
Ammonia,
Magnefia, ,
Glucina,
Alumina,
Zirconia,
Metallic oxides,
Silica.
Sect. XL Of Phosphorous Acid.
1. The phofphorous acid bears the fame relation to
the phofphoric as the fulphurous acid does to the ful- ^
phuric. It is combined with oxygen in the fmaller Formation,
proportion. This was demonftrated by Lavoifier in
1777, when he pointed out the difference between the
product from the flow or rapid combuftion of phofpho¬
rus. It is obtained by the flow combuftion of phof¬
phorus at the common temperature of the air. If phof¬
phorus, in fmall pieces, be expofed to the air in a glafs
funnel placed in a bottle, it attra&s the oxygen and
moifture from the atmofphere, and runs down into
the bottle. This is the phofphorous acid. By this
procefs, about three times the weight of the phofpho¬
rus is obtained. _ ... 5®^.
2. It is then in the form of a white thick liquid,Propertied
adhering to the fides of the veffel. It varies in con-
fiftence according to the ftate of the air. Its fpecific
gravity
Acids.
588
Aftioa of
heat.
S89
Cxygen.
59°
Hydrogen.
S9i
OJ acids.
592
Compoiu
tion.
* Four tray
Ccnnaifs.
Chim. tom.
ii. p. 85.
Lagrange,
i. 183.
593
Compounds
594
Affinities.
gravity is not known. It has an acid, pungent tafte,
not different from phofphoric acid. It alfo reddens
vegetable blue colours.
2. The phofphorous acid is not altered by light.
When expofed to heat in a retort, part of the water
combined with it is firft driven off, and when it is con¬
centrated, bubbles of air fuddenly rife to the furface,
and colleft in the form of white fmoke, and fometimes
inflame, if there be any air in the apparatus. If the
experiment be made in an open veffel, each bubble of
air, when it comes to the furface, produces a vivid de¬
flagration, and diffufes the odour of phofphorated hy¬
drogen g^s. This inflammable gas continues to be
evolved for a long time, and when the adlion ceafes,
phofphoric acid only remains behind. It ought to be
obferved, that the phofphorated hydrogen gas is not
difengaged till the phofphorous acid is concentrated and
brought to a high temperature, which feems to prove
that the phofphorus which is not faturated with oxy¬
gen, ftrongly adheres to it.
4. There is little attraction between oxygen and
phofphorous acid, which feems to be owing to the
great affinity between phofphorus and phofphoric acid.
It abforbs, however, very flowly, a fmall quantity of
oxygen j and even after long boiling, it is not com¬
pletely converted into phofphoric acid.
Hydrogen gas has no adtion on phofphorous acid }
but this acid is decompofed at a red heat, by means of
charcoal, which feparates from it a greater quantity
of phofphorus than from phofphoric acid. I here is no
a£fion between thefe bodies in the cold. Sulphur has
no a&ion on this acid at the ordinary temperature of
the atmofphere, and they cannot be combined by
means of heat, becaufe the phofphorus is diflipated
before it unites with the fulphur.
6. There is no aCtion between phofphorous acid and
fulphuric acid in the cold ; but when they are heated
together to the boiling temperature, the phofphorous
acid deprives the fulphuric of part of its oxygen, and
is converted into phofphoric acid, wdrile part of the ful¬
phuric acid thus decompofed, is difengaged in the
ftate of fulphurous acid gas. Phofphorous acid pro¬
duces a fimilar effeft on nitric acid. The phofphorus
is converted into phofphoric acid, and part of the ni¬
tric acid is converted into nitrous gas.
This acid is compofed of the fame conftituent
parts as the phofphoric, and is confidered by fome as
the phofphoric acid holding in folution a fmall quanti¬
ty of phofphorus *.
8. Phofphorous acid forms compounds with alkalies,
earths, and metallic oxides, which are known under
the name of phofphites.
9. The order of its affinities is the following.
C H E M I s T R Y.
Sect. XII. Of Carbonic Acid.
Lime,
Barytes,
Strontites,
Potafli,
Soda,
Ammonia,
Glucina,
Alumina,
Zirconia,
Metallic oxides.
1. When a piece of charcoal in a ftate of ignition,
is plunged into a jar of oxygen gas, it burns with great
brilliancy-, and after the combuftion has ceafed, the 593
air in the vefiel is totally changed. If a little water is Formation,
introduced into the jar, and agitated, the air combines
with it j and this water, when examined, exhibits acid
properties. This is the carbonic acid. It is iormed
by the combination of carbone and oxygen. I his is
one of the moft important acids, both on account of
its numerous combinations, and al!o on account of the
difcovery of it having occafioned a total revolution in.
chemical fcience. ^
2. It was regarded by the ancients, on account or
the noxious effefts which it produced as a peftilential ,.96
vapour, and they gave it the name oiffiirltus Names.
Paracelfus and Van Helmont confidered it as a peculiar
matter, to which they gave the name, fpiritus fyhe-
Jiris, or gas. Hales, although he confidered it merely
as contaminated air, diftinguiftied it by the name of
fixed airy becaufe it entered into the compofition of
many bodies. Dr Black demonftrated, that it is a
peculiar fubftance, different from the air j that lime,
magnefia, and the alkalies, were deprived of their
caufticity, by being combined with this air, and there¬
fore he gave it the name of fixed air. It was aiter-
wards found by the experiments of Keir and Bergman,
to be an acid, and hence Bergman gave it the name
of aerial acid. The nature and properties of this acid
were inveftigated by many chemical philofophers, and
from them it received various names, as mephitic acid,
calcareous or cretaceous acid, thus diftinguifhed horn
its effefts, or from the fubftances from which it was
obtained. In the prefent chemical nomenclature it
has the name of carbonic acid, from its bafe carbone. S97
3. For fome time after the difcovery of the differ-At^ftaipr
ence between carbonic acid and common air, and its
properties as an acid, it was confidered by many as a
Ample elementary fubftance, and it was regarded as
the acidifying principle. In the progrefs of inveftiga-
tion it was found to be a compound fubftance, and
that oxygen was one of its conftituent parts, and it was
generally believed that phlogifton conftituted the other.
When hydrogen was fubftituted for phlogifton, it was
fuppofed that oxygen and hydrogen conftituted car¬
bonic acid. The difcovery of Mr Cavendifh, proved
that water, not carbonic acid, was the produdt of
the combination of oxygen and hydrogen. But the
experiments of Lavoifier have eftabliihed the fact, and
placed it beyond difpute. He .demonftrated. that the
weight of the carbonic acid which was obtained, was
exactly equal to the quantity of the oxygen and char¬
coal which had difappeared. 5518
4. Carbonic acid may be obtained by taking a quan- Method of
tity of chalk or limeftone, or marble, , and reducing obtaining,
them to a coarfe powder. Introduce it into a matraf.s,
pour over it a quantity of diluted fulphuric or nitric
acids 5 a violent effervefcence takes place, carbonic
acid gas is difengaged, which pafles over, and may be
received in veffels in the ufual way. I he chemical
aftion that takes place in this change muft be.obvious.
The affinity of the fulphuric acid for the lime isftrong-
3 U 2 er
599
Properties.
600
Abforbed
by water.
C H E M I
cr than that of the carbonic acid, which is previoufly
in combination with it; the fulphuric acid, therefore,
feizes the lime, and the carbonic acid is difengaged in
the {fate of gas.
5. Carbonic acid thus obtained in the ftate of gas,
is an invifible, elaftic fluid. Its fpecific gravity is
0.0018. One hundred cubic inches of it weigh 46.5
grs. It is nearly double the weight of common air.
It has no fmell; it is totally unfit for refpiration, and
equally fo for fupporting combuftion. It reddens the
tindlure of turnfole, which has its blue colour reftored
on being expofed to the air, by the feparation of the
acid.
6. Water abforbs a confiderable proportion of this
acid, which is increafed by agitation. At the tempe¬
rature of 410 water abforbs its own bulk. When arti¬
ficial preflure is employed, the quantity of gas abforb¬
ed may be greatly increafed. It is in this way that
■what are called the aerated alkaline waters are pre¬
pared, fome of which, it is faid, contain no lefs than
three times their bulk of the gas. Water impregnated
with this gas, acquires an acidulous tafte, and when
poured from one veflel to another, has a fparkling ap¬
pearance. When water impregnated with this acid is
expofed to the air, it ioon difappears. The air of the
atmofphere attracts it from the water, having a ftrong-
er affinity for it than the water.
When water containing this gas is raifed to the boil¬
ing temperature, the whole is driven off y and if wa¬
ter impregnated with it be expofed to the temperature
of 3 2°, the whole of the gas feparates during the
freezing.
b^li^it oT 7. Carbonic acid undergoes no change by the action
heat. ^ght. ^ is n°t changed by the aftion of heat in
clofe veffels, or by palling it through a red-hot
tube.
8. There is no aftion between this gas and oxygen.
Expofed to the air of the atmofphere, it is gradually
diffipated. The air of the atmofphere generally con¬
tains from .01 to .02 parts of this gas.
9. There is no aftion between this acid and azote.
Charcoal has no chemical a£Hon on carbonic acid y
but when it is heated, it has the property of abforbing
and condenfing within its pores the carbonic acid y but
the acid is feparated by plunging the charcoal under
water.
10. Phofphorus has no action on carbonic acid ; but
by the aid of compound affinity, phofphorus can de-
compofe it.
11. Sulphur has Hill lefs aflion on carbonic acid
than phofphorus. It is faid, indeed, that a fmall
quantity of fulphur is diffblved by this gas by means
of heat, which gives it partly the fetid odour of ful-
phurated hydrogen gas.
1 2. Carbonic acid gas mixed with carbonated, phof-
phorated, and fulphurated hydrogen gafes, diminifhes
the combuftibility of thefe inflammable gafes.
601
Not altered
602
Attrafted
by the air.
603
Abforbed
by char¬
coal.
(*oq
Dimimfhes
combuftibi-
Iny.
605
606
Affinities.
Compounds. 13. The carbonic acid combines with the alkalies
fome of the earths, and metallic oxides, forming com¬
pounds known by the name of carbonates.
14. The following is the order of the affinities of
this acid.
Barytes,
Strontites,
Lime,
S T R Y.
Potalh,
Soda,
Magnefia,
Ammonia,
Glucina,
Zirconia,
Metallic oxides.
607
15. Carbonic acid exifts in great abundance in na-Very abun.
ture. It is produced during the proceffes of combuf-^301,
tion and refpiration, and the fermentation of vegetable
matters. Hence it is found in pits and caverns, where
there is a ftagnation of the air, and being fpecificalljr
heavier than common air, it remains at the bottom.
This is the reafon why fmall quadrupeds, as dogs, are
inflantly fuffocated, becaufe they refpire only this gas,
when they enter places where it is accumulated. This
has been long obferved in the celebrated Grotto dellCa-
ni in Italy, where dogs are inilantly fuffocated *, while
men, whole heads are in the ftratum of common air
near the top of the cavern, receive no injury. Men Fataleftedta
have been fuddenly killed by going down into large produced
vats, in which the procefs of fermentation had been^14,
carried on. In confequence of the greater fpecific gra¬
vity of the carbonic acid gas, and the great quantity
generated during the procefs, when the fermented li¬
quor is drawn off, it finks to the bottom of the veffel,
and there remains till it is difplaced by a denfer fluid,
or flowly attrafted by the air. Similar accidents have
happened to perfons going down into pits or wHls
which have been long Ihut up, and where the air has
been long ftagnant. It is by refpiring this gas that
perfons are luffocated who have been expoled to the
fumes of burning charcoal in clofe places. During
the combuftion of the charcoal, the carbone combines
with the oxygen of the atmofphere ; carbonic acid is 509
formed, which foon fills the apartment. In thefe Mode of
cafes, where life is not totally extinguiffied, the belt recovery,
method of recovery is faid to be, to daih cold water
on the head and body y a praftice which is commonly
obferved in accidents of this kind, in northern coun¬
tries, where charcoal is burnt in clofe apartments.
Sect. XIII. Of sJrsenic Acid.
610
1. This acid, and the four following, have metallic Five metal,
fubftances for their bafe. Moft metallic fubftanceslic aci(ls-
combine with oxygen in different proportions, and the
compounds formed with thefe fubftances and oxygen,
are denominated oxides, becaufe they poffefs no acid
properties; but fome of the metals combine with oxy¬
gen in greater proportion, which gives them the cha-
rafteriftic properties of acid fubftances.
2. The metallic fubftance arfenic, combines with
oxygen in two proportions •, the firft, which is ufually
called the white oxide of arfenic, has been denominat¬
ed by Fourcroy, the arfenious acid. Macquer difeo-
vered fome of the combinations of arfenic acid, previ¬
ous to the year 1746 •, for he fhews that a mixture of
white oxide of arlenic and nitre, fubjefted to the ac¬
tion of a ftrong fire, yields a neutral fait, to which he
gave the name of the neutral fait of arfenic. But it
was by the inveftigation of Schsele in 1775
properties were fully known.^ . . _ procefV for
3. The procefs for obtaining it which was pointed obtaining
out it.
Acid*.
C HEMISTRY.
Acid*-
612
Properties.
613
Adtion of
water.
614
Of combu
ftibles.
<>I5
Compofi-
tion..
out by Scbeele, is the following. Take three parts of
the white oxide of arfenic, and diffolve tt m feven
parts of muriatic acid. Add five parts of nitric
acid to the folution, and diftil it to drynefs. The arie-
nic acid remains behind. It may alfo be procuied by
diffolving the white oxide in liquid oxymuriatic acid,
or by making a ftream of oxymuriatic acid gas pals
through a folution of the white oxide of arfenic. 'i he
chemical aftion wdiich takes place in thefe procefles,
is the union of the arfenic with an additional portion
of oxygen, which it derives from the nitric acid, the
liquid oxymuriatic, or the oxyinuriaUc acid gas. _
By whatever procefs it is obtained, the arfenic
acid which is not cryftallized has an acid, cauftic, and
metallic tafte. It reddens the fyrup of violets, and
its fpecific gravity is 3.91* When it is expofed to a
ftrong heat in a retort or crucible, it fufes, attacks the
glafs of the retort, or the earth of the crucible j it_ re¬
mains tranfparent and pure at a high temperature, gives
out a little oxygen, and is partly converted into white
oxide. f
5. Expofed to the air, it attrafts the moiiture from
it, and abforbs two thirds of its own-weight of water
from the atmofphere, which is fufficient to hold it in fo¬
lution. .
6. The arfenic acid is much more foluble in water
than the white oxide. Three or four parts of water are
fufficient to diffolve it. When it is evaporated, it at
fumes a thick confidence like honey. #
7. Combudible fubdances decompofe arfemc acid,
’ by depriving it of part of its oxygen, and converting
it into the white oxide. Hydrogen gas mixed with a
folution of this acid, has the property of precipitating
it. Charcoal, phofphorus, and fulphur produce a fimi-
lar effieft. Expofed in a retort to heat.with charcoal ;
the charcoal is inflamed, and the arfenic acid is redu¬
ced to the metallic date. . Sulphur heated with arfenic
acid, is partly converted into fulphurous acid gas, and
partly fublimed into the red fulphuret of arfenic. When
heated with phofphorus, part of the phofphorus is con¬
verted into phofphoric acid, and the arfenic reduced to
the metallic date, unites with another part of the phof¬
phorus, with which it forms a phofphuret of arfenic,
which fublimes.
8. The arfenic acid is compofed oi the white oxide
of arfenic and oxygen. The proportions of its condi¬
ment parts, according to the experiments of Proud, are
65 arfenic,
35 oxygen.
616
Pompoun^
617
Affinities.
ICO
9. The compounds which arfenic acid forms with
alkalies, earths, and fome metallic oxides, are known
by the name ot arferuates.
10. The order of its affinities is the following.:
Lime,
Barytes,
Strontites,
Magnefia,
Potaffi,
Soda,
Ammonia,
Glucina,
Alumina,
Zirconia.
Sect. XIV. Of the Tungstic Jcid.
I. In the year 1781, Scheele and Bergman, in in-Hiftory,
vedigating the nature of a heavy done (called tungden
by the Swedes), difcovered that it is compofed of lime
combined with a peculiar acid. Their difcovery was
afterwards confirmed by feveral chemids, and particu¬
larly by the experiments of the D’Elhuyarts, who de¬
tected the fame acid in the mineral called wolfram.. $l9
2 This acid always exids in combination with lime Method of
and’iron. It may be obtained by reducing the former obtaining,
to a fine powder, and treating it with nitric or muriatic
acids, which unite with the lime, and then by alkalies,
which diffolve the acid. The alkaline lolution is to
be precipitated by the nitric or muriatic acid j the pre¬
cipitate is to be carefully wadied and dried, which is
the tungdic acid in the folid date. 620
a. The tungdic acid thus prepared, is in the form ofProporne,
a white powder, which has an acid and metallic tade,
changes the colour of vegetable blues into red ; and has
a fpecific gravity according to Bergman, equal to 621
3.600. Heated under the blow-pipe, this tungdic acid A^°n oi
becomes fird yellow, then brown, and at lad black 5 it
affords no fmoke, and gives nofignof fufion. When it
is calcined for fome time in a crucible, it is deprived oi
the property of diffolving in water. T, • of water;--
4: Expofed to the air it fuffers no change. It is
foluble in 20 parts of boiling water, but it is partially
feparated on cooling. This folution has an acid tade,
and reddens the tinfture of turnfole. Heated with
charcoal, it is reduced, but with difficulty,.to the metal¬
lic date. With fulphur and phofphorus it becomes ot
a gray colour,,but without reduaion. ^
r. The acids do not diffolve the tungdic acid in the™ac. -
form of white powder, but they change completely its
properties. The fulphuric acid changes it to a blue,
and the nitric and muriatic acids convert it into a fine
yellow colour. In this date it has lod its tade and
folubility, has become ffpecifically heavier, and has ac¬
quired the property of forming falts with the lame bales
dibir.aiy different from thofe formed with what was
called the white acid. The Spanidi chemids I) Elhuy-
arts, confider the latter as an acidulous triple fait, and
yellow oxide as the real tungdic acid..
6. Vauquelin and Hecht, who indituted a let ot ex¬
periments on thefe oxides, as they propofe^ to denomi¬
nate them, obtained the fame refults. They confider
the tungdic acid of Scheele as a triple fait, which has 524
retained a portion of the acid by which it was prec.pi- Only
tated in its compolition, and when the oxide of tunglten^
is pure, it poffeffes none of the- properties which are
admitted and acknowledged as the charabteridics oi.the
acids, but that it has a drong tendency to. form triple
combinations, in which only it exhibits acid properties.
The compounds which it forms with, the alkalies,
earths, and metallic oxides, are a fpecies 01 neutral
falts •, but the chemical combination is not fully com- ^
pleted to hide the alkaline properties of the former *.
In forming thefe compounds., it is the only property m xix p-’a5<
which it agrees with the acids, ^he compounds au
denominated tungdates. . Tungdatec
7. The order of its affinities is the following :
Lime,
Barytes,
Stror. tiles,
526
Acids.
C H E M
Strontites,
Magnefia,
Potafh,
Soda,
Ammonia,
Glucina,
Alumina,
Zirconia.
627
Hiltoiy.
628
Proceffes
for obtain¬
ing it.
629
Properties.
630
Action of
beat.
631
Of water.
Sect. XV. Of Molybdic Acid.
1. This acid was difcovered by Scheele in the year
1778. It is a compound of the metallic fubftance
molybdena and oxygen. Scheele fuppofed that it ex-
ifled in the mineral from which he obtained it, and
that this mineral was a compound of the acid, fulphur
and iron. The experiments of later chemifts have
fhown that the acid is formed in the procefs of prepar¬
ing it, by the metal combining with oxygen.
2. There are various proceffes for the preparation of
this acid.
a. Scheele found that by treating a little of the ful-
phuret of molybdena (fulphur combined with the me¬
tal) on a filver plate, the wdrite fumes which exhaled
from it, adhered to the plate in form of a fmall fcale of
a brilliant yellowilh white colour, which was the true
molybdic acid. But a very fmall quantity can only
be obtained in this way.
b. Another procefs is by means of nitric acid. On
one part of fulphuret of molybdena in pow7der, pour
five parts of nitric acid, and diftil it to drynefs. The
fame procefs is repeated three or four times. The dry
refiduum is a white powder, which is the molybdic
acid mixed with the fulphuric acid, which is alfo form¬
ed during the procefs with the nitric acid. The ful¬
phuric acid may be wafhed off with hot water, and the
molybdie acid remains behind in a ftate of purity.
c. It may be alfo prepared by projecting into a red-
hot crucible three parts of nitrate of potafh, and one
part of fulphuret of molybdena reduced to fine powder
and well mixed together. A red rnafs remains after
the detonation compofed of the oxide of iron, of the
fulphate of potalh, and the molybdate of potafh. By
throwing the mafs into water, the two falts are diffolved,
and the oxide of iron is precipitated. Evaporate the
folution to obtain the fulphate of potafh, and drop in¬
to the liquid which refufes to cryflallize, and which
fhould be diluted with water, fulphuric acid, till there
is no farther precipitation. The precipitate is molybdic
acid, but not in a ftate of perfeCl purity 5 for it is com¬
bined with a certain portion of potafh.
3. The molybdic acid prepared in this manner, and
fufficiently purified, is a white powder of a fharp me¬
tallic tafte. According to Bergman, the fpecific gra¬
vity is 3.4.
4. When heated in a large glafs retort, it yields a
little fulphurous acid. But when it is expofed to a
ftrong heat in a clofe veffel, it fufes, attaches it-
felf to the fides of the veffel, and cryftallizes on cool¬
ing in rays going out from a centre. But if at the
moment the acid is in fufion the veffel be uncovered,
it rifes into a white fmoke by contaCl with air, and
this vapour attaches itfelf to cold bodies in form of
brilliant fcales of a golden-yellow colour.
It is readily foluble in warm water. One part of
the acid requires about 500 grs. the folution is of a
1
I S T R Y.
yellow colour, has little fmell, and reddens litmus pa- Acids.
per' ... , .
5. Molybdic acid is decompofed by charcoal, with ofdiarcoff
the afliftance of heat j it is alfo decompofed by ful-and ful¬
phur, with the extrication of fulphurous acid, and thephur.
formation of fulphuret of molybdena.
6. The concentrated fulphuric acid diflblves a con- Of acids,
fiderable quantity of molybdic acid, with the aid of
heat. The folution on cooling becomes of a violet
blue colour, which difappears when it is heated. The
muriatic acid diffblves a confiderable proportion by
boiling. When this folution is diftilled to drynefs,
one part of the acid is fublimed, of a blue and white
colour. The nitric acid has no effedl whatever *. r
7. Molybdic acid combines readily with the al- x7*89 p -89
kaline and earthy bafes, which have the name of 634
molybdates. Compounds.
8. This acid has not been applied to any ufe.
Sect. XVI. Of Chromic Acid.
635
1. This acid was difcovered by Vauquelin in the Difcovery.
year 1797. It has only been found in fmall quantity,
in combination with lead or iron.
2. Chromic acid may be obtained by boiling the red Prepara-
lead ore of Siberia in a folution of carbonate of potalh,t;on*
and precipitating it by means of another acid, which
has a ftronger attraftion fur the potafh. A red or
yellow orange powder falls to the bottom, which is
chromic acid.
3. It has an acrid and peculiar metallic tafte, more
perceptible than any other metallic acid.
4. When expofed to the aftion of light and caloric,
in open veffels, it affumes a green colour 3 but in clofe
veffels, it gives out pure oxygen gas, and lofing its acid
properties it returns to the ftate of green oxide. This
is the only metallic acid, which by the adtion of caloric,
eafily parts with its oxygen.
5. Strongly heated with charcoal, chromic acid be-Adlionof
comes black, and is eafily reduced to the metallic ftate charcoal,
without fufion. It is probable alfo, that it may be
decompofed with equal facility by hydrogen, phofpho-
rus, and fulphur. 535
6. Chromic acid is foluble in water, and cryftallizes Water,
by cooling and evaporation, in prifms of a ruby red
colour. 639
7. The muriatic acid by diftillation with a moderate Muriatic
heat with the chromic acid, paffes to the ftate of oxy-ac^‘
muriatic acid, and the mixture acquires the property of
diffolving gold. In this refpedl it refembles the nitric
acid, and it is the only metallic acid which is diftin-
guilhed by this property. 540
8. The chromic acid combines readily with the al-Compounds,
kalies, and has the peculiar property of giving an
orange colour to the cryftals: from this it derived its
name. The compounds are called chromates. ^
9. The chromic acid, from its peculiar colour, and Ufes.
the beautiful colours which it communicates to other
bodies, promifes to be ufeful in painting on porcelain
and glafs, or even in dying.
Sect. XVII. Of Colvmbic Acid.
642
I. The laft of the metallic acids is the columbicjDifcovery.
which was difcovered by Mr Hatchet in 1801. In
the
Acids.
643
Prepara¬
tion.
644.
Properties.
«4S
Adlion of
heat.
646
Of acids.
* Phil.
'Iran/
1802. p. 44.
647
Hiftory.
648
Names.
649
Prepara¬
tion.
C H E M I
the ore from which it was extra&ed, it is combined
•with oxide of iron, from which it was feparated, by
expofing it to a ftrong red-heat, with five times its
weight of carbonate of potafh. The alkali combined
with part of the acid, and from this it was feparated by
water. By repeatedly filling the refiduum with potalh,
he feparated the whole of the acid from the iron,
which latter combined with muriatic acid that was
added to it. By treating the alkaline folution with
nitric acid, a precipitate of a white, fiakey, infoluble
fubftance was obtained. This is the columbic acid.
2. It is of a pure white colour, but not very heavy,
and has fcarcely any perceptible tafte ; it is not foluble
in boiling water. When fome of the powder is placed
upon litmus paper, moiftened with diftilled water, the
paper in a few minutes becomes red. When expofed
to the blow-pipe, it is not fufible, but only becomes of
a lefs brilliant white.
3. It is diffolved in boiling fulphuric acid, and
forms a tranfparent colourlefs folution, w’hich is only
permanent while the acid is in a concentrated Hate j
for if it be diluted with wrnter, it affumes a milky ap¬
pearance *, a white precipitate is depofited, which, as
it dries on the filter, changes w'hen completely dry to
a brownilh gray. It is then infoluble in water, has no
tafte, is femitranfparent, and breaks with a gloffy, vi¬
treous fra&ure. This compound appears to be formed
of the fulphuric and columbic acids. Nitric acid has
no effedt on the columbic acid *.
S T R Y.
Thus, the procefs is carried on by alternately empty¬
ing and filling the veffels till vinegar is formed, which
generally requires a period of from 12 to 15 days. 650
3. Vinegar is generally of a yellowifti colour, an Properties,
acid tafte, and agreeable fmell. It reddens vegetable
blues, and when it is expofed to heat, it is entirely dif-
fipated. The fpecific gravity varies from 1.005 to
1.0251. It varies confiderably in colour, fpecific
gravity, and other properties, according to the fub-
ftances from which it has been obtained. Vinegar in
this ftate is extremely apt to be decompofed. Scheele
has pointed out a very fimple procefs, by which it may
be preferved for a long time. Put the vinegar into
bottles, and place them over the fire in a vefl'el filled
with water. Let the water boil for a moment, and
then take out the bottles, after which it may be kept
for feveral years. gvj
4. To feparate the impurities with which vinegar Purified by
is contaminated, it is diftilled with a moderate heat} diftillation,
the temperature muft not exceed that of boiling water,
and the procefs ftiould be carried on only till about \
of the quantity have palled over. This is diftilled
vinegar, or the acetous acid of the chemifts. It is
then perfeftly tianfparent and colourlefs, has an agree¬
able odour, and a ftrong acid tafte. The vinegar in
this ftate, wdien expofed to a fufficient degree of cold,
is partly frozen. As the ice which is formed confifts
almoft entirely of water, when it is feparated the
fluid which remains is the vinegar highly concentra-
Sect. XVIII. Of Acetic Acid.
1. The acetic acid or vinegar w^as one of the earlieft
known. This indeed ryas to be expe&ed, from the
manner and the abundance in which it is produced, as
it is the firft change to wdiich wine and fimilar liquids
are fubjeft. The lournefs which exifts in thefe liquids,
is owing to the production of this acid. It has differ¬
ent names, according to the ftate in which it is found.
When it is firft prepared, it is known under the name
of vinegar; when purified by diftillation, it is called
dijlilled vinegar •, and when it is ftrongly concentrated,
it is called radical vinegar, or acetic acid.
2. The procefs by which vinegar is obtained is the
fermenting procefs of many vegetable matters, wdiat is
ufually denominated the acetous fermentation, or the
fecond ftage of the fermentative procefs of vegetable
matters. The circumftances in which this fermenta¬
tion takes place are, a temperature between 70° and
8o°, the addition of fome fermenting fubftance, and
expofure to the air.
The procefs which is recommended by Boerhaave,
is generally followed. Two large hoglheads are pre¬
pared, by fixing about a foot from the bottom, a grat¬
ing of rods, on which vine branches are to be placed.
The wine to be fermented is poured into the veffels j
the one is to be filled to the top, and the other only
one half. They are both left expofed to the air.
Fermentation begins in the veffel which is half full;
when it is completely begun, fill it up from the other
veffel, wdiich interrupts the fermentation in the full
hogftiead, and it commences in that which is half full.
When this has continued for a little time, it is filled
up from the other veffel, in w7hich the fermentation
again commences, and is interrupted in the other.
ted. 65*'
5. To prepare what has been denominated radical radical
vinegar, a fait of which this acid forms a component, vine^ar‘
part muft be decompofed. The acetate of copper, or
verdigris, is generally employed for this purpoie. It is
reduced to powder, and diftilled in a retort with a
ftrong heat. The liquid which firft comes over is in-
fipid and colourlefs, and muft be kept feparate from
the remaining part of the product, which is the acetic
acid in a highly concentrated ftate. It has generally
a green colour, being contaminated with a little cop¬
per, but it may be purified by diftillation with a mode¬
rate heat, by which it is rendered colourlefs.
6. The acid in this ftate was at firft confidered by Acetous
chemifts as different from the acetous acid in its pro- ai\d acetic
perties, affinities, and in the compounds it forms with t^p“e
other bodies. This was the opinion of the celebrated different,
chemical philofopher Berthollet, and this opinion was
adopted by almoft all chemifts. It was fuppofed that
it was the acetous acid in combination with another
portion of oxygen, and hence it was denominated, ac¬
cording to the prefent nomenclature, acetic acid. 654
7. The nature and properties of thefe two fuppofed Found to be
acids were at laft inveftigated fully by Adet and Dar-^ famc*
racq, who proved that there was no difference in the
proportion of oxygen in the acetous and acetic acids.
This conclufion was controverted by Chaptal and Da-
bit, who endeavoured to fupport the opinion of Ber¬
thollet, that the two acids are diftinguifhed from each
other by different properties and different combinations
with other bodies. It is now generally admitted, that
what have been called the acetous and acetic acids,
are effentially the fame, their apparent differences de¬
pending on the quantity of water, mucilage and other
fubftances with which the acetous acid is combined. ,
8. This acid when pure, is tranfparent and colour- Fropeipes.
lefs.
£2'8 G H E M
Acids, lefs. In the ftate of acetous acid, it has an agreeable,
aromatic odour. In the ftate of acetic acid, or when
it is highly concentrated, it acquires a (harp, penetrat-
.ing odour, different from that of the vinegar, and in
rthis ffate it is extremely acrid. Applied to the Ikin it
reddens and deftroys it. It is highly volatile } and
when expofed to the open air, it is foon diflipatcd.
656 When heated imcontafl with the air, it inflames.
.Cryftallizes. g4 This acid may be obtained in cryftals, by forming
diflilled vinegar into a pafte with charcoal, and fub-
657 getting the mixture to a temperature which does not
Action of exceed 21a0. By this heat the watery part is diflipat-
; heat. e(j} and the acid remains behind ; but when a ftronger
heat is applied, the acid itfelf is driven off. By re¬
peating this procefs the acid may be obtained cryftal-
lized.
10. Acetic acid undergoes no perceptible change by
the a£Hon of oxygen, hydrogen, or azotic gafes, and
,<SS8 it is not altered by charcoal, phofphorus, or fulphur..
Of acids. 11. Acetic acid is decompofed by the fulphuric acid.
It abforbs carbonic acid, and diflolves boracic acid.
It is alfo decompofed by nitric acid, and is converted
into carbonic acid and water, _Dr Higgins analyzed
the acetic acid by decompofing it in combination with
an alkali. He diftilled in a glafs retort 7680 grs. of
659 acetate of potaih/ that is, potaftr combined with acetic
Analyfis. anci obtained the following produ&s.
Potafli,
Carbonic acid gas,
Carbonated hydrogen gas,
Charcoal,
Oil,
Water,
Deficiency,
3862.9940
1473.5640
1047.6018
0078.0000
0180.0000
0340.0000
0726.9402
Dr Higgins was at a lofs to account for this defici¬
ency, till by repeated experiments he found that it is
always owing to the water and oil, and chiefly to the
water which is carried off by the elaftic fluids. He
ftates the quantity of water carried off in vapour at
700 grs. and the quantity of oil carried off in the fame
way at 26.9402, which together make up the whole
fExpert- deficiency The potalh remained behind unaltered 5
?nents and the acetic acid, therefore, has been decompofed and
Obferva- has yielded the produ&s which were’obtained by diftil-
tlons, p. 27. iat;on> Tut the conftituent principles of thefe pro-
du61s are oxygen, hydrogen, and carbone*, and from
the proportions of oxygen and carbone which enter in¬
to the compofition of carbonic acid, the proportions
of carbone and hydrogen in carbonated hydrogen gas,
and of oxygen and hydrogen in the compofition
Compofi of water, 100 parts of acetic acid are compofed of
tion. about
50 oxygen,
36 carbone,
14 hydrogen.
100
Compounds. 12. The compounds which acetic acid forms with
alkalies, earths, and metallic oxides, are denominated
* 662 acetates. ^ , r „ .
Affinities. j^. The order of its affinities is the following.
1 s T R y.
Barytes,
Potalh,
Soda,
Strontites,
Lime,
Ammonia,
Magnefia,
Metallic oxides,
Glucina,
Alumina,
Zirconia.
Sect. XIX. Of Oxalic Acid.
Acids.
j. This acid exifts ready formed in the oxalis ace to- bound m
fella or wood-forrel, and fome other fpecies belonging Pian
to the fame genus of plants. From this it derives the
name of oxalic acid. It was originally denominated
the faccharine acid, or the acid of fugar, becaule it was
obtained from that fubllance. Its properties were
firft particularly inveftigated by Bergman and Scheele,
and the method of preparing it is given by the for¬
mer. . . 664
2. An ounce of white fugar in powder is put into 4 Method of
retort, with three ounces of ftrong nitric aid. During obtaining,
the folution, a great quantity of fumes of the nitrous
acid efcapes. Apply heat till the liquor boils, and ni¬
trous gas is then driven off. When the liquor in the
retort acquires a reddilh brown colour, add three ounces
more of nitric acid j continue the boiling till the fumes
ceafe, and the colour of the liquor vanilhes. Pour eut
the liquor into a wide lhallow veffel j and, when it
cools, cryftals will be formed in (lender four-fided
prifms, which may be colle&ed and dried on blotting
paper. The cryftals thus obtained may be again dif-
folved in diftilled water, and evaporated to obtain new
cryftals. The oxalic acid may be obtained by a (imp
lar procefs, from other vegetable, and from fome ani¬
mal fubftances, as gum arable, alcohol and honey. 66$
3. Prepared in this way, oxalic acid is in the con-Properties,
crete ftate, cryftallized in four-fided prifms, terminating
in two-fided fummits. They are white and tranfparent,
and have confiderable luftre. They have a ftrong
(harp tafte, and change vegetable blues into a red co¬
lour, and produce the fame effea on all vegetables ex¬
cept the indigo.
The acid properties of this fubftance are (o ftrong,
that one part of concrete oxalic acid gives to 3600
parts of water, the property of reddening paper ftained
with turnfole. „ , , . . f.66 ,
4. When the oxalic acid is expofed to heat, it is vo- Adhon et
latilized, partly in a liquid, and alfo in a folid and cry- eat-
(lalline form. It is not decompofed, but at a high
temperature •, but when it is expofed to a moderate
heat it dries, is covered with a white cruft, and is
foon reduced to powTder. It lofes A> weig^lt when
put upon burning charcoal j it exhales a pungent, irri¬
tating fmoke, and there remains behind a white alka¬
line refidue. ... 1 • •
5. This acid is deliquefeent in the air, when it is O* water.
loaded with moifture. Cold water diffolves about 4- its
weight of the acid ; boiling water diffolves a quantity
equal to its own weight. # 668<T
6. Oxalic acid is decompofed by the fulphuric acid
with the affiftance of heat, and charcoal is depofited j
at
Acids.
^ Cei/inaljs.
Cbm. tom.
yii. p. 225.
668
Compounds
669
Affinities.
670
Hiitory,
671
Prepara¬
tion.
C H E M
at the boiling temperature it is decompofed by the ni¬
tric acid, and converted into water and carbonic acid.
According to Fourcroy, the component parts of oxalic
acid, as they have been afcertained by him and Vau-
quelin, are
77 oxygen,
13 carbone,
lo hydrogen.
' 100 *
7. Oxalic acid combines with the alkalies, earths,
and metallic oxides, and the falls thus formed are di-
ftinguifhed by the name of oxalates.
8. The affinities of this acid are in the following
order :
Lime,
Barytes,
Strontites,
Magnelia,
Potaffi,
Soda,
Ammonia,
* Alumina.
Sect. XX. Of Tartaric Aciv.
1. This acid was procured by Scheele in a feparate
flate, in the year I770> the procefs for which he com¬
municated to M. Retzius, who publiffied the account
of it in the Swediffi Memoirs for that year. It was the
firfl: difcovery in the bright career of that diftinguiffi-
ed chemift.
2. The procefs which he followed was by boiling a
quantity of the fubftance called tartar, or cream of tar¬
tar, in water, and adding powdered chalk till effer-
vefcence ceafes, and the liquid no longer reddens ve¬
getable blues. It is then allowed to cool •, the liquor
is filtered j and a white infoluble powder remains on
the filter, which is carefully removed and well waffi-
cd. This is put into a matrafs, and a quantity of ful-
phuric acid, equal in weight to the chalk employed, di¬
luted with water, is poured upon it. The mixture is
allowed to digeft for 12 hours on a fand bath, ftirring
it occafionally with a glafs rod. The fulphuric acid
combines with the lime, and forms a fulphate of lime,
which falls to the bottom. The liquid contains the
tartaric acid diffblved in it. This is decanted off, and
a little acetate of lead is dropt into it, as a left to de¬
left the fulphuric acid, fhould any remain. With it
it forms an infoluble precipitate ; and if this be the
cafe, it muff be digefted again with more tartrate of
lime, to carry off what remains of the fulphuric acid.
It is then evaporated, and about 4 of the weight of the
tartar employed is obtained, of concrete tartaric acid.
To purify this, the cryftals may be diffolved in diftill-
ed water, and again evaporated ,and cryftallized. It
feems probable, Fourcroy obferves, that this acid ex-
ifts in a ftate of purity in feme vegetables. Vau-
Vol.V. Part II.
i s t r y.
quelin has found a 64th part in the pulp of the ta¬
marind.
3. Tartaric (or tartarous) acid thus obtained, is in crystals,
the form of very fine needle-ffiaped cryftals, but they
have been differently deferibed by different chemifts.
According to Bergman, they are in the form of fmall
plates attached by one extremity, and diverging at the
other. They have been found by others grouped toge¬
ther in the fhape of needles, pyramids, regular fix-fided
prifms, and fquare and fmall rhomboidal plates. The
fpecific gravity is 1.5962. 573
4. This acid has a very ffiarp, pungent tafte j di- Properties,
luted with water, it refembles the tafte of lemon
juice; and it reddens ftrongly blue vegetable co¬
lours. tf74
5. When it is expofed to heat on burning coals, it Adtion of
melts, blackens, emits fumes, froths up, and exhales aheat"
a {harp, pungent vapour. It then burns with a blue
flame, and leaves behind a fpongy mafs of charcoal, in
which fome traces of lime have been detefted. Four
ounces of the concrete cryftallized acid, carefully di-
ftilled, gave the following produfts * : * Fourcroy
Connaifs.
Cub.In. Chim. tom.
431 ckrbonic acid gas,
120 carbonated hydrogen gas.
vu. p. 255
675
6. In the decompofition of the tartaric acid by heat, Adtion of
one of the moft remarkable produfts which particular-*‘eat'
ly charafterizes it, is an acid liquid of a reddiffi colour,
which amounts to one-fourth part of the weight of the
former. This was formerly known by the name of
pyrotartarous acid. It has a {lightly acid tafte, pro¬
duces a difagreeable fenfation on the tongue, is ftrong¬
ly empyreumatic, and reddens the tinfture of turnfole.
But it has been found by the experiments of Fourcroy
and Vauquelin, to be the acetic acid impregnated with \ sinn.de
an oil f (O; . . .
7. Tartaric acid is very foluble in water. The fpe-xSXV.
cific gravity of a folution formed by Bergman, w!as 676
found to be 1.230. This folution in water is not liable Water,
to fpontaneous decompofition, unlefs it is diluted.
While it is concentrated, it lofes nothing of its acid
nature or its other properties. 677
8. Bergman fuppofed that the tartarous acid could Converted
not be changed by the ftrongeft mineral acids, andmt0 oxallc'
efpecially by the nitric ; but Hermftadt has fucceeded
in converting it into oxalic acid by feveral fucceffive
diftillations, with fix times its weight of nitric acid.
Three hundred and fixty parts of tartaric acid yielded
560 parts of oxalic acid, which fhews that it had com¬
bined with a great additional proportion of oxygen L f Feurcroy
9. According to the analyfis of Fourcroy and Vau- C*nnaifu
quelin, 100 parts of this acid are compofed of
70.5 oxygen,
19.0 carbone,
10.5 hydrogen,
Chim. tom.
vii. p. 256.
678
Compofi-
tion.
100.0
3X
10. The
(O The pyromucous and the pyroligneous acids are to be regarded in the fame light. The peculiar proper¬
ties which were fuppofed to diftinguifti them from other acids^ were found by the fame philofophers to be owing
to a fimilar impregnation.
“Aft-:;
CHEMISTRY.
6'i9
Affinities.
681
Prepara
tion.
53°
Acids. 10. The affinities of this acid are in the following
1 order.
Lime,
Barytes,
Strontites,
Magnefia,
Potafh,
Soda,
Ammonia,
Alumina.
Sect. XXI. Of Citric Jcid.
68f. i. The four or acid tafte of the juice of lemons and
SitT m oranges is well known. This.is the citric acid, but it
is mixed with water and mucilage and various pro-
ceffes have been propoled to obtain it in a date of purity.
2. The fir ft which fucceeded was propofed by M.
Georgius, an account of which was pubhlhed in the
Swedifli memoirs for the year 177.4. His procefs was
the following. It confifted in filling bottles.with le¬
mon juice, fhutting them up clofe, and placing them
for fome time in a cellar to feparate the mucilage. He
afterwards expofed it to a temperature of about. 24 ;
the w’atcry part froze, and carried with it a .portion of
mucilage/ This was removed, and the liquid part
which remained was again frozen, till the folid part
had a perceptible acid tafte. The juice, thus reduced
to one-eighth part of its original bulk, is eight times
ftronger, and requires the (ame quantity of potafli fot
faturation. In this ftate of concentration it was pre-
ferved.
Procefs of 3- Bllt in tllis ftatC h Is n0t pUre* We r'u
Scheele. ed to Scheele for the difcovery of the procefs by winch
it is obtained in a ftate of purity, and for afcertaimng
the charafters by which it is diftinguiftied from tarta¬
ric acid, with which it was formerly confounded.
Lemon juice which has been filtered, is laturated with
pow'dered chalk. While the chalk is added, an effer-
vefcence takes place, which is owing to the combina¬
tion of the citric acid with the lime, and the lepara-
tion of the carbonic acid from it in the ftate of gas.
When the effervefcence ceafes, a white powder falls
to the bottom. This is the lime combined with the
citric acid. Waflr this powder with warm water till
it paffes off colourlefs, then put the fait which has been
waftied into a matrafs with a little water.. Take fuch a
quantity of concentrated fulphuric acid diluted with fix
or feven parts of water as may be neceffary to faturate
the lime which has been employed 5 boil it for a few
minutes, then let it cool, and filter the liquor. T e
fulphate of lime formed by the decompofition^of the
calcareous citrate, remains upon the filter. Ihe. fil¬
tered liquor contains the pure citric acid, which is to
be evaporated to the confiftence of a fyrup, and to be
fet by in a cool place to cryftallize. Fhe citric acid
is thus obtained in fmall cryftals.
ExcJs of Scheele thinks that it is neceffary to add a fmall ex-
acid to be cefs of fulphuric acid, to take up the whole or the
added. lime from the citric acid. But Dize is of opinion that
this excefs of fulphuric acid is only neceffary, to de-
ftroy the remaining portion of mucilage which adheres
* fourty , cjtric acid/and thus to feparate from it every
'iJon/iaifs. r t n. *
Chin. tom. extraneous fubftance
*ii. p. 304.
But it has been obferved,. that when an excefs of Acids. .
fulpkuric acid is employed, it may aft upon the citric ^
acid itfelf, decompole it, and produce the black mat- suppofed
ter which was fuppofed to be owing to tne mucilage u> be un-
which adhered to it. And it appears, from an invefti- neceffary.
gation by Prouft on the preparation of this acid, that
when too much fulphuric acid is employed, it decom-
pofes the citric acid, and prevents it from cryftallizing.
To prevent this, a fmall quantity of chalk is added.
He found that four ounces of chalk were neceffary ior
the faturation of 94 ounces of lemon juice, and that
the produft which he obtained amounted to 7-J ounces
of citrate of lime *, and to decompole this, he added
20 ounces of diluted fulphuric acid f. f Journ. ds
4. When the citric acid is pure, it cryftalhzes in Phyf. 53.
rhomboidal prifms, whofe fides are inclined to each P-br¬
other at angles of 6o° and 12 0°, terminating at eac*1 propertic?,
end in four trapezoidal faces which include the folid
angles. By flow cooling of large quantities of the fo-
lution of the pure acid, evaporated to the conftftence
of fyrup, Dize obtained very fine cryftals.
5. The citric acid has a very ftrong acid tafte, and
even feems to be cauftic ; but when it is diluted with
water, the tafte is cooling and agreeable. It has a very
flight odour of lemons, and it reddens blue vegetable
colours. f?5 -
6. When expofed to heat, it melts rapidly m its Adionof
own water of cryftallization. When the folid acid isheat.
put upon burning coals, it quickly fules, froths up,
exhales a (harp, penetrating vapour, and is reduced to
the ftate of charcoal. Diftilled in a retort, it is paitly
difengaged without decompofition, feems to be con¬
verted partly into vinegar, and then yields carbonic
acid gas, carbonated hydrogen gas, and there remains
in the retort a mafs of light charcoal. ggy
7. Expofed to the air, it effiorefces in a dry, warm Water,
atmofphere *, but when the air is rooift, it abforbs wa¬
ter, and lofes its cryftalline form. It is very foluble
in water. Seventy-five parts of water diffolve 100 of
the acid. . ^
8. Sulphuric acid, when concentrated, converts it Acids.
into’acetic acid. It is alfo decompofed by the nitric
acid, which converts it partly into oxalic acid, but
the greater proportion into acetic acid. 65^
o. From the experiments which have been made Compofi-
with this acid, by decompofing it by means of other tion.
acids, and the produfts which it affords, and its con-
verfion into acids whofe component parts are known,
it feems to be pretty certain that oxygen, hydrogen,
and carbone enter into the compofition of citric acid. 690
10. This acid enters into combination with alkalies, Compoumb
earths, and metallic oxides, and forms falts which are
denominated citrates. # f ..
11. The affinities of the citric acid are the follow-Affinities.
ing.
Lime,
Barytes,
Strontites,
Magnefia,
Potaftr,
Soda,
Ammonia,
Alumina,
Zirconia.
Sect.
C H E M I
Acids.
Sect. XXII. Malic Acid.
Hi/or\ l. The malic acid is found in peat proportion in
1 ° y* the juices of a great number of fruits. In them it ex-
ifts ready formed, and particularly in the juice of ap¬
ples, from which it has derived its name. In fome
fruits it exifts in fmall quantity, mixed with a great
proportion of citric acid, as in two fpecies of vaccim-
um, oxycoccos and mtis idcea, prunus padus, and fola-
num dulcamara. Thefe acids are found in nearly
equal proportions in fome other fruits, as in the goofe-
berry, cherry, and ftrawberry j but it exifts in great-
eft abundance, and in the greateft purity, in the juice
of apples.
e93 2> it is prepared by the following procefs, which
preparing was difcovered by Scheele. Bruife a quantity of four
ft.   apples, exprefs the juice, and filter it through a linen
cloth. Saturate this juice with potafh, add to the fo-
lution acetate of lead, (fugar of lead) diffolved in
water, and continue the addition till there is no more
precipitation. I he acetic acid combines wdth the
potafh, and remains in the liquid, while the malic acid
unites with the lead, and being infoluble, falls to the
bottom. Wafh the precipitate wdth water, and pour
upon it diluted fulphuric acid. The fulphuric acid
combines with the lead, and forms an infoluble fait,
which falls to the bottom. The malic acid remains
uncombined in the liquid. Care fhould be taken to add
a fufficient quantity of the fulphuric acid to Separate
the whole of the malic acid from the lead, which may
be known by the pure acid tafte unmixed wdth the
fweet tafte of the fait of lead.
OfSa- 3- When this acid is mixed with the citric acid, as
rating from is the cafe in the juices of many fruits, Scheele con-
the citric, trived the following procefs to feparate them. The
juice is firft evaporated to the confiftence of honey ;
alcohol is poured upon it, by which the two acids are
diffolved, and a great quantity of mucilage is feparat-
ed *, the alcohol is then evaporated the refidue after
evaporation is diluted with tw7o parts of water, and la-
turated with chalk, which combines with both the
acids. The citrate of lime, which is the leaft foluble,
is feparated by evaporation j the malate of lime, or the
combination with the malic acid, may be a:fo feparat¬
ed, by adding another portion of alcohol, which does
not diffolve the fait, but a faccharine matter which
had combined with the malate of lime. 1 he malic
acid may then be feparated as before, with the folution
of the fugar of lead.
Obtained 4* Vauquelin has extracted a very pure and nearly
From houfe-colourlefs malic acid from the juice of houfe-leek,
deck. (fempervivum te&orum, Lin.) It exifts in this juice
combined with lime. He extrafted it by evaporating
the juice, pouring alcohol upon the refidue to feparate a
fmall quantity of fugar which it contained, and by add¬
ing to the remaining matter an equal weight of con¬
centrated fulphuric acid, previoufly diluted wdth feven
or eight times the quantity of water. But as fome
traces^of fulphate of lime are always found in the ma¬
lic acid prepared in this way, he preiers the following
method.
* Annul, de Add to the juice, a folution of fugar of lead ", a pre-
Cbim. 34. cipitate is formed, which is to be decompo.ed by
P-* I27* means of diluted fulphuric acid *.
S T R Y. 531
5. The malic acid thus obtained, is a reddifh brown ^ Acids.
liquid, of a pungent acid tafte, leaving afterwards the
fenfation of fweetnefs. It reddens blue vegetable co- pr0 ’ f,rties
lours. It never affumes a cryftalline form, but be¬
comes thick and vifcid like fyrup *, and when expofed
to dry air, it dries in thin ftrata like a brilliant var-
nifh, for which purpofe it might be employed on po-
lithed furfaces f. i Fourcroy
6. The malic acid is very readily dfecompofed by Connaifs.
heat. It becomes of a dark colour, fwells up, exhales Chim. tom.
a thick acrid vapour in the open air, and leaves be-
hind a bulky mafs of coal. When diftilled in a retort, 0f
it yields an acid water, a great deal of carbonic acid heat,
gas, a little carbonated hydrogen gas, and a light
fpongy coal. _ # 698
7. It is fpontaneoufly decompofed in the veflels inDeconapo-
which it is kept j undergoes a kind of vinous fermen-^ fpon-
tation, and depofits a mucous, flaky fubftance. I his
decompofition is owdng to the intimate re-aCtion of its
conftituent parts. _
8. All the ftrong acids decompofe it. The con- oy nitnc
centrated fulphunc acid chars it 5 and it is converted
into oxalic acid by nitric acid. Scheele diicovercd,
that mucous matters treated with nitric acid, jaaffed to
the ftate of malic acid, or were converted into this
acid, and into oxalic acid. # 7°» .
9. The proportions of the conftituent parts of this Proportions
acid have not been afcertained, but from its ^ecornP°'^ituents
fltion, and the produdls which are thus obtained, it i"unknown;
obvious that it is compofed of oxygen, hydrogen, and
carbone, of which the latter is fuppofed to be in great
proportion. . 701
10. The affinities of this acid are not determined.and alf®
The compounds which it forms with alkalies, earths,
and metallic oxides, are denominated malates.
11. It is very foluble in w'ater.
Sect. XXIII. Of Gallic Acid.
lot
1. This acid exifts moft abundantly in a well known Hiftory.
fubftance, nut galls, and hence it has obtained the
name of gallic acid. It is alfo found in the bark and
wood of many other plants. It was firft examined by
the academicians of Dijon in I772> anc^ ac^ Pro~
perties clearly afcertained , but it is to Scheele that we
are indebted for the difcovery of the procefs by which
it may be obtained pure and cryftallized. The ac¬
count of this procefs was publifhed in I'jSot which is
the following. 703
2. To one part of nut galls, reduced to a coarfePrepara-
powder, add fix parts of pure water. Let the in fufion ti°n-
macerate for 15 days at the temperature of between
70° and 8o° 5 filter it, and put the liquid into a large
glafs or earthen veffel, expofe it to the air, and al¬
low it to evaporate flowly. A thick glutinous pelli¬
cle forms on the top a great quantity of mucous
flakes are precipitated, and the folution has no longer
an aftringent, but a perceptibly acid tafte. At the
end of tw7o or three months, Scheele had obferved on
the fides of the veffels in which the fslution was con¬
tained, a brown cruft Covered with fliining cryftals of
a yellowifti gray colour. He found alfo a great quan¬
tity of thefe cryftals under the thick pellicle which
covered the liquid. He then decanted it, and aoded
alcohol to the urecipitate, the pellicle and the cryftal-
3X2 line
7°4
Another
procefs.
C H E M I
line cruft, and applied heat. The alcohol diffolved
the cryftallized acid, without touching the mucilage.
The folution was now evaporated, and the gallic acid
was obtained pure, in fmall, Ihining cryftals of a yel-
lowifh gray colour.
3. Deyeux has pointed out another method by which,
with proper precautions, the gallic acid may be more
readily obtained. He introduces into a large glafs re¬
tort, a quantity of nut galls reduced to pow’der, and
applies heat flowly and cautioufly, by which he ob¬
tains a large quantity of laminated, brilliant, filvery
cryftals, fufficiently large, and which have all the pro¬
perties of gallic acid. But in following this procefs,
it is neceffary to ©bferve, that the heat muft be very
moderate, and not continued till an oil is difengaged,
which inftantly diiTolves all the cryftals fublimed be¬
fore its appearance *.
4. Mr Davy prepares it by boiling together for fome
time carbonate of barytes, and a folution of gall nuts.
This affords a bluiih green liquor. When diluted ful-
phuric acid is dropt into it, it becomes turbid j ful-
phate of barytes is depoftted, and after filtration, if
the faturation of the earth be complete, a colourlefs
folution of gallic acid, apparently pure, is obtained f.
5. The gallic acid is cryftallized in tranfparent oc¬
tahedrons, or brilliant plates; it has a fharp, pungent,
and auftere tafte, but lefs ftrong and aftringent than
that of the gall nut.
6. This acid is not fenfibly affefled by expofure to
the air. It requires 24 parts of cold water, and about
two-thirds of its weight of boiling wTater, to difiblve it,
from which it can only be cryftallized by a very flow
evaporation.
7. With a moderate heat, it rifes into vapour, which
on cooling is condenfed and cryftallized. In the ftate
of vapour, it has a ftiarp, aromatic odour, refembling
that of the benzoic acid. Every time that it is fu¬
blimed, even with a moderate heat, it is partially de-
compofed j w^ater is formed, an acid liquid, carbonic
acid gas, carbonated hydrogen gas, and fome drops of
a brown coloured oil*, and there remains behind, a great
quantity of coaly matter. ,
8. The concentrated fulphuric acid decompofes and
chars the gallic acid. The nitric acid converts it in¬
to the malic and oxalic acids. The oxymuriatic acid
produces peculiar changes on the gallic acid, but thefe
have not been diftinftly afcertained
9. Although we have not yet treated of metallic
fubftances, it may be neceffary to anticipate a little,
vii. p. 1S3. anft mention the effefts of gallic acid on metallic
Of'wtair ox^es* This indeed is its chief chara&eriftic. On
' 1 c this account, it is much employed by chemifts, to dif-
cover metallic fubftances, wThich are held in folution a-
long with other bodies. Its effeifts on the metallic
oxides are extremely various, and with different metals
it affords different coloured precipitates. The more
readily the metallic oxides give up their oxygen, the
greater is the change produced by the gallic acid. On
fome metallic folutions it has no effedf j fuch are, folu-
tions of platina, of zinc, of tin, of cobalt, and of man-
ganefe. The precipitates of the different metals pro-
# Connalfs,
Chim. viii.
p. 181.
Davy’s.
f Jtur.
Roy. Injlit.
vol. i.
p. 274.
106
Properties.
7°7
Adtion of
water.
708
Of heat.
709
Of acids.
\ Fourcroy
Connaifs.
Chim. tom.
oxides.
S T R Y.
duced by means of the gallic acid, exhibit the follow'- Acids,
ing colours. ^
Gold, Brotvn.
Silver, Browm.
Mercury, Orange-yellow.
Copper, Brown.
Bifmuth, Citron-yellow.
Iron, Black.
Lead, White.
Nickel, Grey.
Antimony, White.
Tellurium, Yellow.
Uranium, Chocolate.
Titanium, Reddilh-brown.
Chromium, Brown.
Columbium, Orange.
711
10. The component parts of gallic acid are the fame Compofi-
as thofe of the other vegetable acids, but having aft011*
greater proportion of carbone j but thefe proportions
have not been afcertained. ^I2
it. The compounds which the gallic acid forms Compounds
with alkalies, earths, and metallic oxides, are denomi¬
nated ^
12. The affinities of this acid have not been afcer-Affinities.,
tained.
Sect. XXIV. Of Benzoic Acid.
7x4
I. The benzoic acid is obtained from feveral plants, Hiftory.
and particularly from theflyrax ben%oe, a tree which
grow’s in Sumatra; from the balfam of Peru and To¬
lu ; from vanilla, and liquid amber. It alfo exifts in
the urine of children, and fometimes in that of adults,
but conftantly in the urine of quadrupeds which live
on grafs and hay, efpecially in that of the horfe and
cow. It is fufpebted alfo that it exifts in many oi the
graffes, and that it is derived from them by means of
the aliment to the urine of the animals in which it is
found. Fourcroy and Vauquelin fufpedft that it exifts
in the fweet-fcented grafs, {anthoxanthum odoratum.
Lin.) which gives the fine flavour to hay *. * Fourcrsy
The firft mention of the benzoic acid is made by Connaifs.
Blaife de Vigenere, who wrote about the commence- Chim. tom.
ment of the 17th century (r). He fays, that he ob-vil‘P’ lS7*
tained, by diftilling benzoin, an acid fait which cryftal¬
lized in needles of a penetrating odour. It was then
called fowers of benzoin, but at prefent benxoic acid. ^
. 2. To obtain this acid by the moft common procefs, Prepara-
put into an earthern pot a quantity of benzoin groislytion.
powdered. Cover the veffel with a cone of paper,
and apply a very gentle heat. The benzoic acid is
fublimed, and attaches itfelf to the fides of the cone,
which may be renewed every two hours. Continue
the procefs till the acid fublimed begins to be colour¬
ed by the oil which is difengaged. By a procefs pro-
pofed by Geoffrey, the benzoin reduced to pow'der is
digefted in warm w;ater, and this being filtered, yields
on cooling needle-fhaped cryftals of the benzoic acid j
but the quantity obtained in this way is very fmall,
which led Scheele to adopt the following procefs. He
took
(p.) Iraite du feu et du fcl} which was printed at Paris in 1608.
G H E M I
Acids.
•ji6
Properties.
717 ,
Adlion of
heat.
718
01 water.
719
Of acids.
720
Compoll-
tion.
took I part of quicklime, to which were added 3 parts
of water, and afterwards about 30 parts more, w'hich is
then to be gradually mixed with 4 parts of powdered
benzoin. Heat the whole on a moderate fire for half
an hour, continually agitating the mixture *, then re¬
move it from the fire, and let it remain at rell for fe-
veral hours. Decant the clear fupernatant liquor, and
add 8 parts more water to the refiduum. Boil it for half
an hour, and mix it with the former. Reduce the liquor
by evaporation to two parts 5 add drop by drop to a
flight excefs, muriatic acid, which caufes the benzoic
acid to precipitate, by leparating it from the lime.
Wadi the precipitate well on a filter 5 and to obtain it
in cryflals, diffolve it in 5 or 6 times its own weight
of boiling water, which on cooling yields cryftals in
the form of long compreffed prilms.
3. Pure benzoic acid is either in the form of a light
pow'der, perceptibly cryftallized, or in the form of very
fmall needles, of which it is extremely difficult to de¬
termine the ffiape. It is white and brilliant, and has
fome degree of dudility and elafticity. It has an a-
crid, pungent, acidulous, and very bitter tafte. In
the cold the odour is flight, but is aromatic, and this
is fufficient to charafterize it. It reddens the tinfture
of turnfole, but has no effe& on the fyrup of violets.
The fpecific gravity of benzoic acid is 0.667.
4. Expofed to a moderate heat, it melts, forms a
foft brown and fpongy body which cools into a folid
cruft, exhibiting on the furface fome appearance of
cryftallization. With a ftronger heat it is fublimed, and
exhales a wffiite acrid vapour, which affefts the eyes.
It burns when brought into contact with flame, and
the whole is confumed without any refiduum. When
it is diftilled in clofe veflels, great part fubliroes un¬
changed, but part is decompofed and yields a vifcid
liquid, a confiderable quantity of oil, and a much
greater quantity of carbonated hydrogen gas than any
other body of this nature. A very fmall portion of
coaly matter remains in the retort.
5. It is not fenfibly changed by expofure to the air.
It is fcarcely foluble in cold water. Four hundred
parts of boiling water difiblve 20 parts of the acid,
19 of which are feparated on cooling.
6. Concentrated fulphuric acid readily difiblves this
acid, and one part of the fulphuric acid palfes into the
ftate of fulphurous acid. Benzoic acid may be feparated
from this folution rvithout having undergone any change,
by adding water. The nitric acid diffolves it in the
fame way, and it is alfo feparated by means of water.
Guyton found, by diftilling nitric acid on the concrete
benzoic acid, that nitrous gas was difengaged, only
towards the end of the procefs, and that the acid it-
felf then fublimed without alteration.
7. As this acid yields by diftiliation oil and carbon¬
ated hydrogen gas, it is obvious that it muft be com-
pofed of carbone and hydrogen, and probably alfo
oxygen, although this latter has not been difcovered
in any experiments that have been made on this fub-
h21 ftance.
Compounds 8. The benzoic acid unites very readily with alka¬
lies, earths, and metallic oxides, and the compounds
which are thus formed are denominated benzoates.
Affinities. 9. The order of the affinities of benzoic acid is the
following.
S T R Y.
White oxide of arfenic,
Potaffi,
Soda,
Ammonia,
Barytes,
Lime,
Magnefia,
Alumina.
Sect. XXV. Of Succinic Acid.
t . •723
1. The fuccinic acid, formerly called volatile fait ofBhl°rJ,‘
amber, was long regarded as an alkaline fait. It was
not till towards the end of the 17th century, that its
acid properties were dilcovered. As amber, the fub-
ftance from which this acid is obtained, is found in
confiderable quantity under ftrata of fubftances which
contain pyrites, it was thought that this acid was
formed by the fulphuric acid. This was the opinion
of Hoffman and Neuman. Amber is found on the
fea-coaft of different countries, efpecially in the Pruf-
fian territory on the ffiores of the Baltic. T he name
of the acid is derived from fuccinum, the Latin name
for this fubftance. _ 724
2. The fuccinic acid may be obtained by the follow- Prepara-,
ing procefs. Introduce a quantity of amber in pow-tion.
der into a retort, and let it be covered with dry land.
Adapt a receiver, and diftill with a moderate heat in
a fand bath. There paffes over firft a liquid which
is of a reddifh colour, and afterwards a volatile acid
fait, which cryftallizes in fmall, white, or yellowifli
needles in the neck of the retort j and if the diftilla-
tion be continued, a white light oil fucceeds, which
becomes brown, thick, and vifcid. I he acid which
is obtained in this way is contaminated with the oil j.
and therefore to feparate this oil, it may be diffolved
in hot water, and palled through a filter on which has
been placed a little cotton moiitened with oil of am¬
ber, which retains the oil, and prevents it from paf-
fing through along with the acid. I he acid may then
be evaporated and cryftallized. Guyton has oblerved,
that the acid may be rendered quite pure, by diftilling
off" it a fufficient quantity of nitric acid, but with this
precaution, that the heat employed is not ftrong enough
to fublime the fuccinic acid *. _ * Ann. ds
3. The acid thus obtained is in the form of white, Chwt un.
ffiining, tranfparent cryftals, which are foliated,, trian-A 1 z
gular, and prifmatic. The tafte is acid, but not cor- pi0pcicies.
rofive. It reddens the tinfture of turnfole, but has no
effedl on the infufion of violets.
4. With the heat of a fand bath, the cryftals of fuc- 01
cinic acid firft; melt, and are then fublimed and con- e
denfed in the upper part of the veffel. I here is, how¬
ever, a partial decompofition, ror there is a coaly mat¬
ter left behind in the veffel. 727,
5. At the temperature of 212°, two parts of water Of water,
diffolve x of this acid, which cryftallizes on cooling.
When the water is cold at the temperature ot 50°,
it requires 96 parts of water to diffolve 1 of the acid. 728
6. This acid like other vegetable acids, is compofed “fi¬
ef oxygen, hydrogen, and carbone; for when it is dii-*1011*
tilled in a retort with a ftrong heat, carbonic acid gas,
and carbonated hydrogen gas are evolved, and char¬
coal
/
729
Compounds
534 _ C H E M
Acids, coal remains behind in the retort. The proportions of
the component parts have not been afcertained.
7. This acid enters into combination with alkalies,
earths, and metallic oxides, and forms with them com-
pounds which are denominated Juccinates.
Affinities. 8. The affinities of this acid are in the following order:
Barytes,
Lime,
Potaffi,
Soda,
Ammonia,
Magnefia,
Alumina,
Metallic oxides.
I S T R Y.
Hiftory.
73*
Prepara¬
tion.
733.
Properties.
734
Adtion of
heat.
* Fourcroy
Ccnnaifs.
dim. tom.
vii. p. 147.
735
Of water.
I Ettcye.
JVLethod. i.
p. apo
737.
Affinities.
Sect. XXVII. Of Camphoric Acic.
Acids.
733
1. This acid is obtained, as the name imports, fromHiitory.
camphor, a concrete fubftance procured from a fpecies
of laurel {Laurus camphor a, Lin.) which is a native
of the Eait Indies.
739
Sect. XXVI. Of Saclactic Acid.
1. To this acid Fourcroy has given the name of Mu¬
cous acid, becaufe it is obtained from gum arabic and
other mucilaginous fubftances; and it was formerly cal¬
led acid of fugar-ofmilk. This latter name it received
from Scheele, who difcovered it in the year 1780,
while he was employed in making experiments on the
fugar of milk, in order to obtain from it oxalic acid,
wdrich he procured from fugar.
2. This acid may be obtained by the following pro-
cefs. To I part of gum arabic, or other mucilaginous
fubftance, add 2 parts of nitric acid in a retort, and
apply a gentle heat. There is at firft difengaged a
little nitrous gas and carbonic acid gas, after which
let the mixture cool. There is then precipitated a
white powder which is flightly acid. This powder is
the facla&ic acid.
3. Thus obtained, facla&ic acid is in the form of
a wdiite powder, a little gritty, and with a weak acid
tafte.
4. It is readily decompofed by heat, and yields an
acid liquor which cryftallizes by reft in the fhape of
needles ; a fmall quantity of an acrid cauftic oil, of a
blood-red colour, carbonic acid gas, and carbonated
hydrogen gas; and there is left behind a confiderable
quantity of coaly matter. It is partly fublimed in
needles or brown plates, with an odour fimilar to that
of benzoic acid *.
5. Sacla&ic acid in the ftate of potvder is not very
foluble in water. Cold water does not take up more
than 200 or 300 parts of its weight 5 boiling water
does not take up above one half more. On cooling,
the acid is depoftted in brilliant fcales, which become
white in the air. The folution has an a,cid tafte. It
reddens the tin&ure of turnfole. Its fpecific gravity
at the temperature of 590 is i.oo^-f-.
6. This acid enters into combination with earths,
alkalies, and metallic oxides 5 and the falls which it
^ 736 d forms are known by the name of faccolates.
ompour c The order of its affinities, according to Bergmann,
is the following.
Lime,
Barytes,
Magnefia,
Potaflr,
Soda,
Ammonia,
Alumina,
Metallic oxides.
2. Camphoric acid was firft obtained by Kofegarten, Prepar
by diftilling nitric acid 8 times fucceffively off cam-ti°n*
phor. This experiment was repeated by Bouillon La¬
grange with the fame refult. He introduced into a
glafs retort, 1 part of camphor, and ffie poured over
it 4 parts of nitric acid. A receiver was adapted to
the retort, and the joinings vcere well luted. The
retort was placed on a fand bath, and a gradual heat
was applied. A great deal of nitrous gas and carbonic
acid gas was difengaged. One part of the camphor is fub¬
limed, and another part feizes on the oxygen of the
nitric acid. The fame procefs muft be repeated till
the w7hole of the camphor is acidified, which is known
by its cryftallizing when the liquor cools which re¬
mains in the retort. Thefe cryftals are camphoric
acid. To purify it, it muft be diffolved in diftilled
warm wTater, and the liquor is then to be filtered and
evaporated to nearly half its volume, or till a thin
pellicle is formed on it. When it cools, cryftals of
pure camphoric acid will be obtained. ^.0
3. The camphorc acid has a flightly acid, bitter Properties,
tafte. It reddens the tindlure of turnfole. The cry¬
ftals refemble, when in a mafs, thofe of the muriate
of ammonia. Expofed to the air the mafs efflorefces.
4. Cold water diffolves this acid with great difficul- Aftion of
ty. An ounce of water at the temperature of between water.
50° and 6o°, cannot diffolve more than 6 grs. while
water at the boiling temperature will hold in folution
eight times that quantity.
5. When this acid is put upon burning coals, it ex- Of heat,
hales a denfe, aromatic vapour j with a leis degree of
heat, it melts, and is fublimed. When put into a heat¬
ed porcelain tube, and if a ftream of oxygen gas be
paffed through it, the acid remains unchanged, but it is
fublimed from the fides of the tube. When diftilled
alone, it firft melts and then fublimes. This fublima-
tion produces fome change in its properties. It no
longer reddens the tin&ure of turnfole, and acquires a
ftrong aromatic odour, and a lefs pungent tafte ; be¬
comes infoluble in water, and in the fulphuric and mu¬
riatic acids. The nitric acid heated, makes it yellow,
and diffolves it *. * Ann. dt
6. The camphoric acid enters into combination with dim. tom.
the alkalies, earths, and metallic oxides, and the com- xxin.p. 170,
pounds thus formed are denominated camphorates. 743
7. The affinities of this acid are the following f.
Lime,
Potalh,
Soda,
Barytes,
Ammonia,
Alumina,
Magnefia.
Sect. XXVIII. Of Suberic Acid.
1. This acid is obtained from cork, a well-known Hiftory
fubftance, which is the bark of a tree (the quercus fiber
Lin,
Compounds
f Ibid.
xxvii. p. 4c.
744
Affinities.
CHEMISTRY.
Acids.
746
Prepara¬
tion.
747 .
Properties
748
Adtion of
light.
749
Of heat.
Lin. or cork-tree.) From the Latin name of this fub-
ftance fuber, the name of the acid is derived, and hence
it is called fuberic acid. The _ acid which is obtain¬
ed from cork, by treating it with nitric acid, was fup-
pofed to be the oxalic acid, on account of pofieffing
fome common properties, and particularly that of
forming with lime an infoluble fait. But the experi¬
ments of Bouillon Lagrange have ihewn, that this is
a peculiar acid.
2. This acid is obtained by the following procefs.
Take a quantity of clean cork, grated down. Intro¬
duce it into a retort, and pour on it fix times its weight
of nitric acid \ the acid ought not to be too concentrat¬
ed. It is then to be diftilled with a moderate heat. The
cork fwells up and becomes yellow’, and there is dif-
engaged a quantity of red vapours ; and as the diftilla-
tion goes on, the cork is diflolved, and fwims on the
furface like foam. If this fcum is not formed, the
cork has not been afted upon by the acid. In this
cafe when the diftillation begins to Hop, return into
the retort the acid which had paffed over into the re¬
ceiver, and diftil as long as any red vapours appear,
and then immediately remove the retort from the fand
bath, and pour out the contents while yet hot into a
glafs or porcelain veffel j put it upon a fand bath and
apply a gentle heat, ftirring it conftantly with a glafs
rod. The matter gradually thickens, and as foon as
white vapours are difengaged, which excite a tickling
in the throat, it is to be removed from the fand bath,
and conftantly ftirred till the mafs is nearly cold. In
this way a fubftance is obtained of the confiftence of
honey, of an orange-yellow colour, of a lharp pene¬
trating odour while it is warm, but which gives out a
peculiar aromatic fmell when it is cold. . , • r
To procure the acid which is contained in this fub¬
ftance, put it into a matrafs, and pour upon it double
its weight of diftilled water. Apply heat till the mafs
becomes liquid, and feparate by filtration that part
which is infoluble in water. The liquor which is ob¬
tained is of a clear, amber colour, and of a peculiar
odour. The filtered liquor on cooling becomes mud¬
dy, is covered with a thin pellicle,. and depofits a
powTdery fediment. The precipitate is to be feparat-
ed from the liquid by filtration, and it is to be dried
with a gentle heat. This precipitate is tne iuberic
acid. The remaining liquor is then to be evaporated
to drynefs with a moderate heat, to obtain the whole
of the acid which it holds in folution.
The acid which is prepared by this process is a lit¬
tle coloured, and may be purified, either by faturating
the fuberic acid with potalh, and precipitating with
an acid, or by boiling it with charcoal powder.
2. Suberic acid is in the lolid form, but it is not
cryftallized. When it is obtained by precipitation, it
is in the ftate of a powder, and by evaporation it is in
the form of thin irregular pellicles. _
4. It has a flightly bitter and acid tafte. Diilolved
in a fmall quantity of boiling water, it tickles the
throat, and excites coughing. It reddens vegetable
blues. f
5. Expofed to the light, it becomes brown after a
certain time ; but this effett is more fpeedily produced
when it is expofed to the fun’s rays. Heated in a
matrafs, the fuberic acid is fublimed, and the glals re¬
mains marked with zones of different colours. It the
fublimation be flopped in time the acid is obtained on
the fides of the veffel, in fmall points formed of concen¬
tric circles. When expoied to the heat of the blow¬
pipe on a fpoon of platina, it fit ft melts, then falls
down into powder, and at laft is totally diflipated by
fublimation.
6. It undergoes no change from the action of oxy¬
gen gas. The’aftion of the acids on fuberic acid is
very w’eak. The folution is not complete, efpecially
when it is impure.
7. Water at the temperature of 60° or 70° diffolves
the concrete acid only in the proportion of lOgrs. to
the ounce. When the acid is very pure, the water
will not diffolve more than 4 grs. Boiling water dif¬
folves half its weight 5 but as the liquor cools, it be¬
comes muddy, and the acid is depofited *.
8. This acid combines with the alkalies, earths,
and metallic oxides, and forms with them compounds
which are known by the name oi/liberates. .
9. The order of its affinities is the following f.
Barytes,
Potafli,
Soda,
Lime,
Ammonia,
Magnefia,
Alumina,
Metallic oxides.
Sect. XXIX. Of Mellitic Aciv.
75°
Of acids.
751
Of water.
* Ann. ds
Chim. tom.
xxiii. p. 42
752 t
Compounds
f Ib id.
P- 57-
753
Affinities.
754
1. This acid is procured from a mineral fubftance Difcoveryv
which was difcovered about the year 1790. Werner
gave it the name of honigjiein, (honeyhone) from its
colour. By other mineralogiits it has been denomi¬
nated mellite, from the Latin name of honey, and
hence the acid which it affords has been called the
mellitic acid. The mineral from which this acid is ob¬
tained feems to be of vegetable origin. It is found in
fmall cryftals among the layers of wood coal at Arten
in Thuringia. In the firlt analyfis to which this mine¬
ral was fubje£!ed no new acid was detected. But in
the year 1799 the acute and accurate Klaproth ex¬
amined its nature and component parts, and found that
it is a compound of a peculiar acid and alumina. His
experiments have been fince repeated by Vauquelin,
and the refult of his analyfis has been fully confirmed. ^
2. It is procured from the mellite by the following procefs for
procefs. The mineral is to be reduced to powder, and obtaining,
boiled with about 72 times its weight of water. The
alumina is precipitated' in the form of flakes, and the
acid combines with the water. By filtration and eva¬
poration, cryftals are depofited, which are the cryilals
of the mellitic acid. ,, _ ’S5
3. This acid cryftallizes in the form of fine needles, Properties.
or in fmall fhort prifms with fhining faces. They are
confiderably hard. It has a ffightly acid tafte, ac¬
companied with fome degree of bitternefs. 757
4. This acid has very little folubility in water, but ^1011 0
it has not been afcertained to what degree ; or what
proportion of water it requires for its folution. 75^
5. A fmall quantity of this acid expoied to the Of heat,
flame of the blow-pipe, at firft gave out fparks like
nitre j and then fwelled up, and left a matter^which
536 CHE M
Acids, penetrated the charcoal. Heated in a crucible of pla-
tina, it fwells up at firft, is then charred, without the
production of any oily vapour, and leaves behind a
* Ann de coaiy alkaline matter *.
Cbim. 6. When the nitric acid is added to this acid, it pro-
xxxvi. 210. duces no other change than giving it a yellowilh co¬
lour. It has not yet converted it into any of the ve¬
getable acids to which it is nearly allied in its proper¬
ties and conflituent parts.
7. According to Klaproth’s analyfis the mineral from
which the acid is obtained confifts of
46 mellitic acid,
16 alumina,
38 water.
759
Of acids.
760
Compofi-
tion.
100
When it was diftilled in a retort the acid was com¬
pletely decompofed ; and the produCts obtained by
Klaproth in this way from 100 grains of mellite were
the following :
54 cubic inches of carbonic acid gas,
13 hydrogen gas,
38 grs. of acidulous water,
I aromatic oil,
9 charcoal,
16 alumina.
The conftituent parts of mellitic acid are obvioufly
carbone, hydrogen, and oxygen. But the proportions
>]6i have not been afeertained.
Compounds 8. The mellitic acid enters into combination with
the earths, alkalies, and metallic oxides, and forms
compounds with them which are called mellates.
Sect. XXX. Of Lactic Acid.
762
Difcovery.
763
Prepara¬
tion.
764 _
Properties.
1. In inveftigating the changes which fpontaneoufly
take place in milk, the celebrated Scheele difeovered
that it contained a peculiar acid. To this has been
given the name of the latlic acid. The formation of
this acid depends on the change of the fugar of milk,
or of the faccharine mucous matter; for after the
acid is once well formed, when the ferous part of the
milk being very four reddens vegetable blues, no more
is obtained by evaporation and cryftallization.
2. Scheele did not fucceed in feparating the acid
from the ferous part of the milk by diftillation. He
therefore contrived the following procefs. He eva¬
porated a quantity of four whey to ^th of its bulk, and
then filtered it to feparate the whole of the coagulated
cheefy matter. He then added lime-wTater to precipi¬
tate the phofphate of lime, and diluted the liquid with
three times its weight of pure water. He then preci¬
pitated the excefs of lime by means of the oxalic acid,
adding no more of the latter than what is neceffary.
He evaporated the folution to the confiftence of honey,
poured on a quantity of alcohol which feparates the
portion of fugar of milk and of other extraneous mat¬
ter, and diffblves the la&ic acid $ and diftilled the
clear filtered liquor till the whole of the alcohol em¬
ployed be driven off: wdiat remains in the retort is the
laftic acid.
3. This acid is never cryftallizedj but always ap-
I S T R Y,
pears in the form of a vifeid mucilaginous fubftance. Acids.
It has a ftrong (harp tafte which is far from being—y~‘—'
agreeable. It reddens the tinfture of turnfole, and
gives a reddilh violet fhade to the fyrup of violets. ^
4. When it is diftilled in a retort it yields an em- Compoii-
pyreumatic acid which is very ftrong and analogous totion-
the tartaric, very little oil, carbonic acid gas, and car¬
bonated hydrogen gas, and a fmall quantity of coaly
matter which adheres to the glafs. This {hews what
are the conftituent parts of this acid, but the propor¬
tions of thefe have not been determined.
5. The compounds with alkalies, earths, and metal-Compounds
lie oxides wThich are formed with the laftic acid, are
denominated laBates. ^
6. The affinities of this acid are in the following Affinities,
order.
Barytes,
Potaftr,
Soda,
Strontites,
Lime,
Ammonia,
Magnefia,
Metallic oxides,
Glucina,
Alumina,
Zirconia.
Sect. XXXI. O/Laccic Acid.
I. The fubftance from which this acid is obtained,Hiftory
is collefled in the neighbourhood of Madras. It was
firft deferibed by Dr Anderfon, who fays that nefts of
infefts refembling fmall cowry {hells were brought to
him from the woods by the natives, wdio eat them with
avidity. Thefe fuppofed nefts, he fhortly afterwards
difeovered to be the coverings of the females of an un-
deferibed fpecies of coccus j and having noticed in the
Abbe Grofier’s account of China, that the Chinefe col-
left a kind of wax, much efteemed by them, under the
name of pela from a coccus depofited for the purpofe of
breeding on certain fhrubs, and managed exaftly in the
fame manner as the Mexicans manage the cochineal
infefts, he followTed the fame procefs with his new in-
fefts, and found means to propagate them with great
facility on trees and ftirubs in the neighbourhood.
This fubftance, which he called white lac, was found and nature
on examination to have a confiderable refemblance to °/ d16 lub-
bees wax. Dr Anderfon fuppofes, that the animal f0™
which fecretes it provides itfelf, by fome means or other, 0ktained.
with a fmall quantity of honey, refembling that pro¬
duced by our bees. The fweetnefs of it tempted the
children who wTere employed to colleft it, to eat fo
much of it as very much to diminiftihis crop. A fmall
quantity of this matter was fent to Europe in 1789.
It was examined by Dr Pearfon, who publiftied an ac¬
count of his analyfis in the Philofophical Tranfaftions
for 1794, from which we have extrafted the informa¬
tion which we now lay before our readers.
A piece of white lac, which weighs from three to
fifteen grains, is fuppofed to be produced by each infeft.
Thefe pieces are about the fize of a pea, of a gray co¬
lour, opaque and roundiih, but with a flat fide, by
which they adhere to the bark. In its dry ftatg, white
lac is foft and tough, and has a faltiftr and bitteriih
I tafte.
Acids.
770
Prepara¬
tion.
771.
Properties.
772
A&ion of
iieat.
773
Compoii-
tion.
* P/ji/.
Tranf.
1794, P-
333.
. 774
Hiftory.
C H .E M
tafle. A watery liquid, which has a flight fait tafte,
oozes out on prefling a piece of this fubflance. White
lac has no fmell, unlefs it be preffed or rubbed, when
it becomes foft, and then it emits a peculiar odour.
When it is gathered from the tree, the pieces of lac are
lighter than bees-wax, but after being melted and puri¬
fied, it finks in water. It melts in alcohol and in wa¬
ter at the temperature of 1450, and very readily in
boiling water.
2. Dr Pearfon expofed 2000 grains of white lac to
fuch a degree of heat as was fufficient to melt them.
They became foft and fluid, and there oozed out 550
grains of a reddilh watery liquid, wdiich emitted the
fmell of newly baked bread. The liquid was filtered
and. purified from extraneous matter. This liquid is
the laccic acid.
3. It has a flightly faltifli tafle, with fome degree of
bitternefs. It fmells when heated like newly baked hot
bread. It reddens the tinflure of turnfole. Its fpeci-
fic gravity, at the temperature ol 6o° is 1.025. When
this liquid remains for fome time at reft, it becomes tur¬
bid, and depofits a fediment. When it is evaporated, it
becomes more turbid ; and allowed to remain at reft, it
affords fmall needle-like cryftals in mucilaginous mat¬
ter.
4. Two hundred and fifty grains of this liquid were
expofed to heat in a fmall retort. As the liquor grew
warm, mucilage-like clouds appeared, but when it grew'
hot, they difappeared. At the temperature of 200*
it diftilled over very faft. On diftillation to drynefs,
a fmall quantity of extra&ive matter remained. The
diftilled liquid was tranfparent and yellowiftr, and while
hot, had the fmell of newly baked bread. Paper ftain-
ed with turnfole which had been put into the receiver,
was not reddened. One hundred grains of yellow'ifli
tranfparent liquid being evaporated till it became turbid,
afforded in the courfe of a night, acicular cryftals
which had a bitterifh tafte. Under a lens they appear¬
ed in a group, fomewhat refembling the umbel of parf-
ley. One hundred grains of yellowifti tranfparent
liquid being evaporated in a low' temperature to drynefs,
a blackiih matter remained behind, which did not en¬
tirely difappear when expofed to pretty ftrong heat ;
but on heating oxalic acid to a Id's degree, it evapo¬
rated, and left no trace behind.
From thefe properties, and from its peculiar adlion
with the alkaline, earthy, and metallic falls, Dr Pearfon
concludes, that this acid is different from any of the
acids already known.
5. The experiments which have been made on white
lac, and on the acid obtained from it, ftiow7 that it is
clofeiy allied to the vegetable acids. Its component
parts, therefore, probably are, carbone, hydrogen, and
oxygen 3 but experiments are ftill wanting fully to af-
certain its nature and properties *.
Sect. XXXII. Of Pruffle Acid.
1. This is one of the moft important acids, both to
the chemift, and to the manufafturer. It has been ai¬
led ged that the ancients w’ere acquainted with Pruffian
blue, which they employed in painting } but Landriani
has fhown, in his differtation on this fubftance, from
the evidence of Theophraftus and Pliny, and from the
analyfis of an Egyptian mummy, that the ancients em-
Vol. V. Part II.
I S T R Y. S27
ployed ultramarine blue and the fmalt or azure of co- ^C1^*
bait $ and that Pruflian blue wdiich is readily a&ed on ’ v
by the fubftances to which it muft have been expofed
in thefe countries, could not refill their influence for fo
many ages, and retain the beautiful colours which are
admired in the paintings of Herculaneum.
2. Stahl relates, in his 300 experiments, that the The dif-
difeovery of Pruflian blue was owing to an accident.coverjr.
About the beginning of the 18th century, Dielbach, a
chemift of Berlin, wilhing to precipitate a deco£Hon of
cochineal with an alkali, borrowed from Dippel fome
potalh, on which he had diftilled feveral times his ani¬
mal oil, and as there w'as fome fulphate of iron in the
decoftion of cochineal, the liquor inftantly exhibited a
beautiful blue in place of a red precipitate. Refleffing
on the circumftances which had taken place, he found
that it was eafy to produce at pleafure, the fame fub¬
ftance, which afterwards became an objedl of commerce.
It obtained the name of Pruffian blue, from the place
where it was difeovered. 776
3. This difeov’ery was announced in the Memoirs ofUrlt an-
the Academy of Berlin, for the year 17 to; but thenounce *
procefs by which it was obtained was kept fecret, that
thofe who were in poffeflion of it might derive the
whole advantage from the manufa&ure. It w'as pu-
bliftied for the firft time by Woodw'ard in the Philofo-
phical Tranfadlions for the year 1^24, who declared,
that it had been fent to him from Germany, by one
of his friends. This is all that is known of the man¬
ner by which this procefs was made public. It is not
certain whether it came originally from the firft inven¬
tors, or wkether it be owing to the refearches of fome
chemift. 777
4. The method which is deferibed by Woodward Proceis,
fucceeds very well. It is by preparing an extemporane¬
ous alkali, by detonating four ounces of nitre, and an
equal quantity of tartar ; then to add four ounces of
bullock’s blood, well dried, and to calcine the whole
with a moderate heat, till the blood be reduced to
a coal, or emit no fmoke capable of blackening
any white body that is expofed to it. Towards the
end of the procefs the fire is to be increafed, till the
crucible which contains the materials fliall be mode¬
rately red. Throw the red-hot matter into w'ater, and
boil it for half an hour ; and having poured off the
firft water, add another quantity, and boil it again.
Repeat this operation till the laft w'ater comes off in-
fipid, then add all the quantities of water together,
and evaporate to the quantity of two pints. To this
liquid the Germans have given the name of blood ley.
By others it has been denominated phlogijlicated alka¬
line ley.
5. A folution of 2 ounces of fulphate of iron, and
8 ounces of alum, in two pints of boiling water, is to
be mixed with the former folution while both are hot.
A great effervefcence takes place ; the liquor becomes
muddy, affumes a greenilh colour, inclining more or
lefs to blue; and a precipitate is formed of the fame co¬
lour. Separate this precipitate, and to heighten the
colour, pour upon it carefully muriatic acid till it no
longer increafes the intenfity of the blue colour; then
w'aflr it with water, and dry it flowfly.
6. Such was the procefs by which Pruffian blue was
obtained, before the theory was difeovered, to account
for the different changes and effedls which it prefented.
3 Y The
538
Acids.
778
Nature of
it invefti-
gated by
feveral clie-
uiifls.
779
By Mac-
yuer.
CHEMISTRY.
The fame year in which Woodward publifhed an ac¬
count of the procefs, Brown inftituted a fet of expe¬
riments, to difcover the nature of this fubftance, and
the circumflances which attended its formation. He
found that flefh, as well as bullock’s blood, poffefled a
fimilar property. He thought that Prufllan blue was
the bituminous part of iron, developed by the alka¬
line ley, and fixed in the aluminous earth. Geoffrey
adopted the fame explanation. He found that, in the
animal kingdom, oils, wool, hartlhorn, fponge, had
the fame effefl with the alkali as the blood, in precipi¬
tating iron of a blue colour *, and that fome vegetable
charcoal treated with the alkali, in fome meafure com¬
municated to it a fimilar property. Neuman difeo-
vered that the animal empyreumatic oils might be em¬
ployed for the fame purpofe. The abbe Menon wTas
of opinion, that the colour of iron is blue”, but that this
colour, ufually difguifed by fbme faline matter, re¬
appears, when it is leparated by the phlogifticated alka¬
line ley, and thus Pruffian blue was only iron precipi¬
tated in its natural ftate. The aluminous earth, he
faw, ferved only to diminilh the intenfity of the colour,
and to give it a more agreeable (hade.
7. It is to the celebrated Macquer that we are in¬
debted for the firlf correhl views in developing the
theory of this procefs. He obferved, 1 .That pure alka¬
lies precipitated iron from its folutions of a yellowcolour.
2. That this precipitate is foluble in acids. 3. That
the blue fecula obtained from the blue phlogifticated
ley after the addition of muriatic acid, was not afted
on by acids. He therefore concluded, that the firft
green precipitate W’as not a homogeneous fubftance,
but a mixture of twm precipitates, the one yellow and
the other blue 5 and that it was fufficient to remove the
firft by any acid, to give to the fecond its full inten-
ftty of colour. Hence he fuppofed, that the acid of
the alum employed in this procefs w7as ufeful in fatu-
rating, in a great meafure, the pure alkaline portion of
the ley, and diminilhing proportionally the yellow pre¬
cipitate of iron. Having found that it was impoflible
to faturate the alkali with a colouring matter by means
of a calcination ”, and, having difeovered that the pure
alkali deprived iron (which was converted into Pruffian
blue) of its charafteriftic properties j and finally, having
afeertained that the alkali which was employed in the
procefs became exaftly fimilar to that which was cal¬
cined with combuftible matters, to prepare it for the
precipitation of iron of a blue colour, and that its al¬
kaline properties difappeared as it was more or lefs
faturated with the colouring matter, he attempted to
faturate it fully. He therefore faturated an alkali fo
completely with the colouring matter, that it under¬
went no change by boiling, and exhibited none of its
alkaline properties by chemical lefts. By this dif-
covery wTe are now in poffefiion of this valuable fub¬
ftance which had been hitherto known under the name
of the faturated ley of the colouring matter of Pruffian
blue.
In the courfe of his experiments Macquer found,
that the faturated ley could not be decompofed by ful-
phuric acid, nor by the folution of alum ; but, on the
contrary, that every metallic fubftance diffolved in an
acid, feparated the phlogiftic matter from all the fixed
and volatile alkalies. Hence he concluded, that in
the procefs of the formation of the Pruflian blue, it is
neceffary that the affinity of the iron fhould combine Acid*-
with that of the acid with the alkali, to form a fumv—J
of affinities capable of effefting the feparation. This
luminous explanation of fo ftriking a procefs, has not
a little contributed to eftabliftr the theory of com¬
pound affinities. 780
8. After the publication of Macquer’s differtation,and others.,
almoft all chemifts were occupied in refearches into the
nature of Pruffian blue, either to difcover the nature
of its principles, or to improve the procefs for prepar¬
ing the colouring matter : but they were chiefly occu¬
pied in examining thofe bodies which were capable of
phlogifticating the alkali, as it was called j and this pro¬
perty was found to exift in a great number of fubftances.
Till the year 1775, no change or modification was pro-
pofed on the theory of Macquer.
9. About this time the celebrated Bergman, in his By Berg-
difl'ertation on eleflive attra&ions, threw new light on man.
this objeft of inveftigation, by confidering the colour¬
ing matter of Pruflian blue as a diftindt acid, and pof-
feft’ed of peculiar attractions. According to Sage,
the alkali which precipitated Pruffian blue was no¬
thing but an alkali faturated with phofphoric acid j
but Lavoifier juftly remarked, that, according to this
theory, the fait formed of phofphoric acid and an alkali
ought to precipitate a folution of fulphate of iron of a
blue colour, which was not the cafe.
Many chemifts examined the nature of this fubftance
by means of heat, and among others Delius and Sco-
poli, Deyeux and Parmentier, Bergman and Erxleben,
fubjedted it to diftillation, the produdl of which was a
quantity of ammonia. By others an oil was obtained
in this procefs, and fometimes a peculiar acid, wdfich
had the properties of the fulphuric acid. The differ¬
ence of thefe refults probably arofe from the different
ftates of purity of the Pruffian blue which wras employed
in the experiment. ^g2
Fontana difeovered that the fulphuric acid diftilled By Fonta-
on Pruffian blue paffed to the ftate of fulphurous acid,na.
and that the colouring matter produced detonation
wTith nitre. Landriani found that it yielded'by diftilla¬
tion, befides ammonia, a fmall portion of liquid per¬
ceptibly acid, and fome oil, and a great quantity of
elaftic fluids, which confifted of azotic and hydrogen
gafes, the latter burning wdth a blue flame, and deto¬
nating ftrongly with oxygen gas. 783
10. But the moft important ftep in the progrefs ofByScheele.
the difeovery of the nature and properties of this
Angular fubftance, was made by Scheele, an account
of which he publiftied in twm differtations in the Stock- ^
holm tranfaftions for 1782 and 1783. He began byHeexa-
examining the blood-ley, and he found by expofing n.ines the
it for fome time to the air, that it loft the property of16?”
precipitating iron of a blue colour, and the precipitate
which it then yields is foluble in acids. To difcover
what change had taken place on the air, he put fome
of the ley frefh prepared into a large glafs globe clofe
{hut up, and he found fome time after, that neither
the air nor the ley had undergone any change. He
concluded, therefore, that the colouring matter was ^
not pure phlogifton. He fufpe&ed that carbonic acidEffedt of
might have fome effeft in changing the nature of the carbonic
alkali when expofed to the open air. He filled aacid”
globe with carbonic acid gas, and having introduced
a quantity of the Pruffian alkali, he kept it clofe {hut
up
)
Adds.
785
Iron fixes
the colour
ing princi'
pie.
787
It is dif-
G H E M
up for 24 hours, after which, on examining the alkali,
it gave a precipitate which wTas foluble in the acids j
the change, then, mufl have been occafioned by the
carbonic acid gas. He repeated this experiment by
adding to the colouring matter a fmall quantity of ful-
phate of iron. This matter was not changed by the
a&ion of the carbonic acid gas. The fame refult was
obfcrved when he boiled the colouring matter in an
oxide of iron precipitated by an alkali. It fuffered no
change in the carbonic acid gas, but precipitated the
iron as before. The iron then has the property of fix-
r" ing the colouring principle, of defending it againft the
a&ion of carbonic acid gas ; and hence it happens that
the neutral colouring fait formed with an alkali boiled
on Pruflxan blue, does not fo eafily lofe its properties.
But if the colouring ley be digefted on an oxide of
iron, as that wdiich is obtained from the fulphate of
iron boiled in nitric acid, and afterwards precipitated
by an alkali, no effeft is produced. By this digeftion
the aclion of the gas is not prevented, and if the ful¬
phate of iron be added, even with an excels of acid
there is no longer a produdlion of Pruffian blue.
To difcover what happened to the colouring princi¬
ple, w'hen it was charged with the carbonic acid gas,
Scheele introduced into a globe filled with this gas,
fome of the Prufllan alkali, and fufpended in it a bit
of paper, previoully dipped in a folution of fulphate of
iron, and on which he had let fall tw^o drops of alka¬
line liquor to precipitate the iron. The paper was re¬
moved at the end of two hours, and was covered with
a fine blue colour, with the addition of a little muria¬
tic acid. The fame experiments repeated with alkali
faturated with excels of fulphuric acid, gave the fame
refult ; that is to fay, the paper charged with oxide of
iron and fufpended as above, became of a blue colour
on adding muriatic acid. Hence it follows, that the
7S9
engaged by colouring principle is diiengaged by acids, with-
acids. out decompofition, for it ftill has the property of be¬
ing fixed with oxide of iron with which it comes in
contact. Thus he found that the colouring matter
might be feparated from the fubftances with which it
was generally in combination, and without undergoing
„g8 decompofition.
To Separate 11. To obtain it, therefore, in a feparate ftate, he con-
the colour- trived the followdng procefs. He put into a glafs vef-
ing matter. pej two parts Df pru{fian blue reduced to powder, one
part of red oxide of mercury, and fix parts of water.
He boiled the mixture for fome minutes, continually
llirring it. It then affumes a yellowilh green colour.
He put the whole on a filter, and poured upon the re-
fiduum two parts more of boiling water, to wafli it
completely. This liquid is a folution of mercury com¬
bined with the colouring matter, which has the me¬
tallic tafte, and is neither precipitated by acids nor
alkalies. Pour this liquid into a glafs veffel upon one-
half part of clean iron filings, and a fmaller quantity
of concentrated fulphuric acid. Shake the mixture
well for fome minutes, when it becomes black by the
reduftion of the mercury. The liquid then lofes its
metallic tafte, and gives out the odour which is pecu¬
liar to the colouring matter. Having allowed it to re¬
main at reft for fome time, it is poured off, put into a
retort to which a receiver is adapted, and diftilled with
a gentle heat. One-fourth part of the liquid only
fhould be allowed to pafs over, for the colouring mat-
I S T R Y.
ter is much more volatile than water, and confequent-
ly riles firft. The liquid in the receiver is commonly
mixed with a little fulphuric acid, from which it may
be feparated by diftilling again off a little powdered
chalk, which takes up the fulphuric acid. The liquid Pr«ffic acid
then paffes over in a ftate of purity. This is the pruf- obtained-
fie acid. „„„
12. In this procefs the oxide of mercury which was Nature of
mixed with the colouring matter, takes it from the this procefs.
iron with which it is combined in the ftate of Pruftian
blue, and is then a cryftallizable prufliate of mercury.
The iron which is added in the metallic ftate, reduces
the oxide of mercury, and at the moment it combines
with the fulphuric acid, which has alfo been added,
the heat applied fublimes the pruflic acid which has
been difengaged from the mercury, wdiich is now re¬
duced to the metallic ftate. The pruflic acid thus ob¬
tained, partly in the liquid, and partly in the gafeous
ftate, combined with alkalies, produces the fame ef¬
fects as the blood ley, and the colourlefs Pruflian
blue.
13. Having obtained the pruflic acid in a feparate Compofu
ftate, it was his next object to difcover its component t‘on°
parts. Pie had obferved in the procefs for procuring
it, that the air in the receiver was inflammable, and
in decompofing the prufliates, he obtained ammonia
and carbonic acid, and found that fome metals were
reduced by diftillation with the metallic prufliates.
He concluded from this, that the pruflic acid was
compofed of ammonia and oil, and he endeavoured to
prove this by the teft of experiment} but he fcon
found that he could not fucceed in forming the colour¬
ing compound, by combining ammonia and the differ¬
ent oils heated together. Seeing that w^ater was an
obftacle to the formation of the pruflic acid, he con¬
duced his experiments in a different way, by combin¬
ing the ammonia with the dry combuftible principle,
which he fuppofed exifted in oils, and wdth the carbo¬
nic acid, equally in the dry ftate. He faw that char¬
coal alone, ftrongly heated wdth fixed alkalies, gave
them the property of colouring iron blue. Having
heated thefe twm fubftances in crucibles, he added to
the one muriate of ammonia, at the moment when the
firft mixture had acquired a white heat, and he con¬
tinued the heat till no more vapour was difengaged.
This procefs furnilhed him with a pure Pruflian al¬
kali, whilft the combination of the alkali and the
charcoal, without the addition of the muriate of am¬
monia, afforded none. ^
14. Such was the ftate of our knowledge with Berthollet’s
regard to the colouring matter of Pruflian blue,
when Berthollet, at the end of 1787, communicatedment!'
to the Academy of Sciences, the refult of his invefti-
gations into the nature and properties of this fubftance.
He repeated the experiments of Scheele, improved
and extended his views, and confirmed his conclufions.
The refult of his refearches on this fubftance was elofe-
ly conne&ed with the light which he had thrown on
the nature and compofition of ammonia fome years be¬
fore. He proved that the alkaline prufliate is a triple
fait, wTich is compofed of profile acid, the alkali
and iron ; that when it is evaporated and re-diffolved,
it affords cryftals in the form of o&ahedrons ; and mix¬
ed with fulphuric acid, and expofed to the fun, there
is precipitated Pruflian blue, which does not happen
3 Y 2 in
C H E M
in the dark. Alter thefe preliminary experiments, he
proceeded to the examination of pruffic acid, by the
action of oxymuriatic acid. This acid, in proportion
as it is diflblved in the pruffic acid, is deprived of its
oxygen, and is converted into the itate of muriatic
acid. The pruflic acid becomes more odorous and
volatile, and lefs fufceptible of combination with the
alkalies, precipitating iron from its folutions, of a
green colour. This green precipitate recovers its blue
colour when expofed to the light, by contaft with
Oxy-pruffic fulphurous acid, by iron. It is the oxy-pruffic acid,
acid. When the oxymuriatic acid is ftill continued to be ad¬
ded in the date of gas, and is expofed to the light, the
new acid feparates from the water, and is precipitated
to the bottom in the form of an aromatic oil, which
is converted by heat to an infolubie vapour, which is
no longer capable of combining with iron. Thus fu~
peroxygenated, this acid can no longer return to its
original date. It is totally different in its proper-
ties.
When the oxypfuffiate of iron, which is prepared
by treating Pruffian blue with'the oxymuriatic acid,
and which is diftinguithed by its green colour, is de¬
prived of its acid, by being brought into contadf with
a cauftic fixed alkali, it is inftantly decompofed, and
is converted into carbonate of ammonia.
I S T R Y.
foon diflipated from the veflels which contain it. It Acid:?,
has no effect on vegetable blues. • 1
18. It is decompofed at a high temperature •, and A^n 0f
when expofed to light, is converted into carbonic heat and
acid, ammonia, and carbonated hydrogen gas. It light,
combines with difficulty with alkalies and earths, and
without deftroying their alkaline properties. ^9g
19. The carbonic acid drives it off from thefe com-Ofearbo-
binations. It deprives the oxymuriatic acid gas of itsmc ac^'
oxygen, and by this addition changes its properties.
It has no aftion on the metals } but it combines with
their oxides, changing the colour, and forming falts
which are in general infolubie.
20. This acid has the greatefl: tendency to form Triple
triple falts wdth the alkaline and metallic bafes. 7 hefe compounds
complex combinations are more permanent and fixed goo
than the firaple alkaline pruffiates. They are not de- not eafily
compofed by carbonic acid, light, air, or the other acids, decompofed
21. The affinities of pruffic acid are the following.
Barytes,
Strontites,
Potafh,
Soda,
Lime,
Magnefia,
Ammonia.
8qi
Affinities.
i 5. Scheele and Bergman wrere of opinion, that the
pruffic acid contained ammonia ready formed. Ber-
thollet, however, concludes from his experiments, that
it only contains the elements, namely, the azote and
hydrogen, both in combination with carbone ; and
Pruffic acid thus he confiders pruffic acid to be a triple compound
a triple of hydrogen, carbone and azote, but he has not been
compound. a^]e t0 afcertam the proportions. He thinks, how'-
ever, that the hydrogen and azote come near to the
* Fourcroy proportions wffiich exiit in ammonia
Connaifs. j 6. In fome experiments by M. Clouet, on the cd-
Chim. tom. iouring matter of Pruffian blue, he attempted to com-
1X> L S^* bine the elements of ammonia with charcoal, with the
view7 of producing the pruffic acid •, but in whatever
proportion he employed them, no colouring matter
was obtained. He therefore concluded, that it wTas
neceffary to combine directly the ammonia with the
charcoal, for the produ£lion of this fubftance. He
took 2 % parts of quicklime in powffier, and mixed them
with one part of fal ammoniac dried, and alfo in the
Hate of powder. He put the mixture into a porcelain
retort, which he placed upon a fand-bath. To the
beak of the retort was adapted a porcelain tube filled
with dry pow'dered charcoal. The porcelain tube
Pruffian paffied acrofs a furnace, in which it might be llrongly
blue form- heated. It was then made red hot, and heat was af-
ed of car- rewards applied to the retort, and the ammonia w as
bone and ciifengaged in t1ne date of gas,, which paffed through
ammonia. ^ red-hot porcelain tube containing the charcoal.
\ Annal.J^ was received in proper veffels, and when
xi T'.3o'n' examined, was found to be the colouring matter of
, Pruffian blue f.
Pnwties 17- d'he pruffic acid thus obtained, is a colourlefs,
ofj’ruffic tranlbarent liquid, having a ftrong odour of peach
acid. flowers, or of bitter almonds.. This odour impregnates
for fome time the faliva of thofe who refpire it. The
tafte is at fiift fvveetifh but foon becomes acrid and
hot. It is apt to excite coughing, and has a flrong
tendency to affurae the gafeous form, and is therefore
Sect. XXXIII. Of Sebacic slew.
Sou
i. The penetrating fumes which are exhaled fromHiitcry.
melted talknv, and which affeft the eyes, the noftrils,
and even the lungs, had been long ago obfeived, and
Olaus Borrichius has thrown out fome hints, warning
againft the danger of being expofed to thefe fumes.
But little attention was paid to their nature and pro¬
perties. Grutzmacher was the firfl who demonftrated
the exiftence of this acid, in a differtation de ojjium
medulla, printed at Leipilc in the year 1748. Rhodes
publifhed a final] work in 1753 at Gottingen, in which
he makes particular mention of this acid. The fol¬
lowing year appeared a differtation by M. Segner, on
the acid of animal fat, which contained a number of
well-condu£led experiments. Crell endeavoured to
improve the procefs for the feparation and purification
of this acid, and to afcei ain the properties of its com¬
binations. Thefe were publiffied in the Philofophical
Tranfaftions for the years 1780 and 1782.
But it appears, as Thenard, who made experiments
on this acid, obferves, that the acid obtained by thofe
■wffio firft treated of the fuhjeff, was either the acetic
acid, or fome acid different from the febacic, the
propert'es of which are quite diftinft from thofe which
had been formerly deferibed. / 803
2. The procefs by which this chemifl obtained theP’epara-
febacic acid is the following. He diftilled a quantity tIon-
of hogs lard, and waffied the produft feveral times
with hot w7ater. He then dropt into it acetate of lead :
there was formed a flakey precipitate, which was ccl-
lefted and dried, put into a retort with fulphuric acid,
and heated. The liquor in the receiver had no acid
charafter; but there appeared in the retort a melted mat¬
ter analogous to fat. This is carefully feparated •, and af¬
ter being wafhed, is boiled with water. By the aftion
of heat the whole is diffolved by the water, and when
it cools, cryftals in the fliape of needles are depofitedi
Thefe
Acids.
804
Properties.
* Ann. dc
Chtm. tom.
xxxix.
P- I9>
805
Hirtory
and names.
806
Properties.
807
A ift ion of
water.
808
Of acids.
869
Of heat.
810
Compoii.
tion.
C H E M I
Thefe are tire febacic acid. To be certain that thefe
were not produced by means of the fulphuric acid, he
wafhed the fat which had been diftilled with water,
which was filtered and evaporated, and needles w’ere
formed, exhibiting exaftly the fame properties. Or,
after having wafhed with water the diftilled fat, he fa-
turated the filtered liquor with potath, evaporated it,
and dropt into it a folution of lead. There was in-
flantlv formed a fait compofed of the febacic acid and
lead. This is to be dtcompofed as before with ful¬
phuric acid. This acid has the following properties.
3. It has no fmell, a flight acid tafte, and reddens
ftrongly the tindlure of turnfole. When heated it
melts like tallowr.
4. It is much more foluble in w'arm than in cold
water. Boiling water faturated with this acid forms a
folid mafs on cooling. It cryflallizes in fmall needles,
but with certain precautions may be obtained in the
form of long, large, and very brilliant plates *.
Sect. XXXIV. Of Uric Acid.
1. This acid was difcovered by Scheele in the year
1776. It was at firft called lithic acid. It conflitutes
one of the component parts of urinary calculi, and is
alfo found in human urine. There is one fpecies of
calculus which is almoft entirely compofed of this Jub¬
ilance. It is that fpecies which refemblcs wood in ap¬
pearance and colour.
2. This acid, as its properties have been defcribed
by Scheele, is thus charadlerized. It is infipid, inodo¬
rous, almoll infoluble in cold water, and foluole only
in about 360 parts of boiling water. It feparates from
this when it cools, into fmall yellowifh cryllals. The
folution in w7ater reddens the tinclure of turnfole.
3. There is fcarcely any aftion between the urie
acid and the fulphuric and muriatic acids. It is folu¬
ble in the concentrated nitric acid, to wdrich it com¬
municates a red colour. It would appear that in this
change of colour the nature of the acid is alio chan¬
ged, for part of it is converted into oxalic acid. Oxy-
muriatic acid very readily a£ls upon uric acid, either
by fufpending a calculus in the liquid acid, or, which
is eafier, by palling a flream of oxymurratic acid gas
through w’ater at the bottom of which is placed the
uric acid in powder. Its colour becomes pale, the fur-
face fwells up, it foftens, and is at laft converted into
a jelly. This part difappears, and is foon diifolved,
giving a milky colour to the liquid. There is extri¬
cated by flow effe'vefceuce fmall bubbles of carbonic
acid gas. The liquid by evaporation gives muriate of
ammonia, acidulous oxalate of ammonia, both cryftal-
lized ; muriatic acid, and malic acid. Thus the oxy-
muriatic acid decompofes the uric acid, and converts
it into ammonia, carbonic, oxalic, and malic acids.
4. When uric acid is didilled, there is a little of it
fublimed without decompofition. It yields alio a very
fmall quantity of oil and water, cryftallized carbonate
of ammonia, carbonic acid gas; and there remains be¬
hind a very black coal without any alkali, and without
any lime.
5. All thefe fafts fhew that uric acid is a compound
of a very peculiar kind, formed of azote, of carbone,
of hydrogen and oxygen, and fufceptible of a great
number of different changes by chemical agents.
s T R y. 541
Inflam-
Sect. XXXV. Of Roiacic Acid.
1. During certain difeafes, the urine, when it cools, ^
depofits a peculiar fubftance which has been denomi- origin,
nated from its colour, which refembles bricks, Inten¬
tions fediment. During fevers, this appearance of the
urine takes place j and in gouty perfons, at the termi¬
nation of the paroxyfms, it is very abundant. And
w’hen this fuddenly difappears, and the urine at the
fame time continues to depofit this fublfance, a relapfe
may be dreaded. It appears in the form of red flakes,
and adheres ftrongly to the lides of the veffel. If the
urine be heated, this fediment is again diffolved. 312
2. This fubflance xvas formerly conlidered by che-Prepara-
mifls as the uric acid. If into frefh urine a little ni-hon.
trie acid is dropt, it becomes muddy, and a precipi¬
tate is formed. The nitric acid, and the fubltance
to which the name of rofaac acid has been given, com- 8lg
bine together, and are depofited. The uric acid being Properties,
much lefs foluble than the rofacic acid, it is very eafy
to feparate them. All that is neceffary is to pour boil¬
ing wrater on the fediments, and to wafh them on the
fame filter, in which cafe the uric acid remains be¬
hind.
Prouft, who made experiments on this fubftance,
conftders it as another charafleriftic of rofacic acid that
it produces with a folution of gold, a cloudy precipi¬
tate of a violet colour *.
Sect. XXXVI. Of Amnwtic Acid.
* Ann. de
Cbim. tom.
xxxvi.
p. 265.
1. A peculiar acid has been detefted in the liquor Properties,
of the amnios of the cow. This was difcovered by
Buniva and Vauquelin. This acid is concrete, white,
and brilliant, has a very flight acid tafte, and reddens
the tinfture of turnfole. It is little foluble in cold wa¬
ter, but diffolves more readily in boiling water, from
whence it is depofited by cooling, in long needle-lhap-
ed cryftals. When this acid is expofed to heat, it
fwells up, and exhales an odour of ammonia fenfibly
mixed with pruflic acid. It leaves behind a volumi¬
nous coal. 815
2. It feems at firft to have fome analogy with the And di-
faclaftic and uric acids, but this is not really the cafe. ft‘n<ft've
The faclaclic acid does not furnifh ammonia by diftil- chdrac"ters*
lation ; the uric acid yields ammonia and pruffic acid
by heat, but it is not equally ioluble in warm water,
and does not cryftallize, in long, white, brilliant nee¬
dles, nor is it foluble in boiling alcohol, as the amni-
otic acid is f. f Ann. de
Cbim. tom-
xxxiii.
Chap. XL Of INFLAMMABLE SUB- p-*79-
STANCES.
The clafs of bodies which we are to examine in this introduc-
chapter, under the title of inflammable fubftances, are tion.
alcohol, ether, and oils. Thefe fubftances are clofely
allied to many of the bodies which were treated of in
"the laft chapter. Their conftituent parts are the fame
with many of the vegetable acids, arranged, however,
in different proportions, and totally different in their
properties and effe&s. The elements of there inflam¬
mable fubfiaimes are carbone and hydrogen chiefly,
but ■
\
542
Inflam¬
mable fub-
ftances.
G H E M
but in Tome there is a triple compound of carbone, of
hydrogen and oxygen j the latter does not exift in that
quantity as to exmbit acid properties, or thefe proper¬
ties are concealed by the proportions of the other con-
ftituent parts. It was therefore thought neceflary to
treat of thefe fubftances in this place, that we might
be early acquainted with their properties, fome of
which are of great importance in chemical refearches,
particularly their effefts on many faline bodies. They
may be regarded, therefore, as valuable inftruments
of chemical analylis. We {hall confider the inflam¬
mable fubftances in the four following fe£lions, namely;
x. Alcohol, 2. Ether, 3. Fixed oils, and 4. Volatile oils.
Sect. I. Of Alcohol.
817
Prepara¬
tion.
818
Different
names.
819
Hiftory.
820
Purification
1. When vegetable matters have been fubjefted to
the vinous fermentation, the fluid is totally changed.
It is converted into a lubftance called wine or beer,
according to the nature of the materials from which it
has been prepared. When this produft, the wine or beer,
is fubjefted to another procefs, a very different produft is
obtained. By diftillation a fluid is obtained of very dif¬
ferent properties from the beer or wine from which it
is extracted. This liquid, •when it is perfeftly pure, is
known in chemiftry by the name of alcohol, or/pint of
wine, becaufe it is produced from wine. It is fome-
times denominated alfo ardent fpirit, from its effefts.
Ardent fpirit, as it is firft obtained by diftillation, is
to be confidered as a mixture of alcohol and water,
becaufe the alcohol in the procefs of diftillation is con-
denfed by water. In this ftate, ardent fpirit is dif¬
ferent in flavour, in colour and in ftrength, according
to the nature of the materials from which it is obtained,
and hence in common language it is diftinguilhed by
different names. When it is obtained from the fer¬
mented juice of the grape, it is known by the name of
brandy ; from that of the fugarcane, by that of rum ;
and from that of farinaceous fubftances by that of
whifky. All thefe fubftances, therefore, are to be
confidered as compofed of alcohol, or pure fpirit of
wine, w7ater, and a peculiar oil, to which the flavour
is owing.
Ardent fpirit, it is fuppofed, was known in the
dark ages. It does not appear, from any of the writ¬
ings of the Greeks or Romans, that they w’ere ac¬
quainted with fuch a liquor. The preparation of it
from wnne, and even the difcovery of alcohol, or pure
fpirit itfelf, is afcribed to Arnold de Villa Nova, who
lived in the 13th century.
2. Ardent fpirit thus obtained, it has been obfer-
ved, is a mixture of alcohol or pure fpirit, water and
oil, with fome colouring matter. To purify it from
thefe fubftances, it is again diftilled ; and to have it
perfeftly pure, this procefs muft be repeated feveral
times. When ardent fpirit is diftilled for the firft
time, after it is extrafted from the fermented liquors,
it is diftinguifhed by the name of reftified fpirits. The
procefs which is recommended by fome is the follow¬
ing. Diftil it in a water bath, till one fourth of the
quantity has paffed over 5 then diftil it again for fe¬
veral times, taking only the firft half of the produft.
Mix all thefe produ&s together, and diftil them with
a very gentle heat ; the firft half of the liquor which
paffes over, is the pureft alcohol that can be obtained j
I S T R Y.
the remainder may be referved for ordinary purpofesf. Inflata*
Even in this ftate, the alcohol thus obtained, contains
a certain proportion of water, to feparate which, ■ ^ >
Boerhaave has given a very good procefs, by means | fourcrBy
of an alkali. Take a quantity of carbonate of potaftr Conuaifs.
which has been expofed to a red heat, to feparate the Chim. tom.
moifture j reduce it to powder, and put it into the?• I42,
fpirit. This fait, on account of its ftrong attra&ion for
w'ater, combines with the water of the alcohol; and this
folution of the alkali having the greater fpecific gravi¬
ty, falls to the bottom. The alcohol which remains
at the top, may be eafily feparated. To purify this
alcohol, from a fmall quantity of potafli which it holds
in folution, it may be rediftilled in a water bath. It
ought to be obferved, however, that the diftillation
ftrould not be carried on till the whole of the alcohol
is driven off, becaufe towards the end of the procefs,
it carries part of the potafti along with it. 821
3. Alcohol thus prepared and purified, is a light,Properties,
tranfparent, and colourlefs liquor, of a {harp, pene¬
trating, agreeable fmell, and of a warm, ftimulat-
ing, acrid tafte. It has the property, in a much great¬
er degree than wine, of producing intoxication. The
fpecific gravity of alcohol when perfedlly pure, is
0.800, but the ftrongeft fpirit wrhich is afforded by
mere diftillation, according to Mr Nicholfon, is 0.820
at the temperature of 710. The alcohol or redlified
fpirit of commerce, has rarely a fpecific gravity below
0.8371. . . 822
4. When alcohol is expofed to the air at a tempera-Volatile,
turc betw’een 50° and 6o°, it evaporates, and when it
is pure, without leaving any refiduum. By this rapid
evaporation it produces great cold, which is very fen-
fibly felt by dipping the fingers in alcohol, and expof- S23
ing them to the air. It boils at the temperature of A(ftiGn of
176°, and is then converted into an elaftic fluid. Inheat*
the vacuum of an air-pump it boils at 56°. It has
never yet been frozen by the greateft degree of cold
to which it has been expofed. It remains fluid when
the thermometer ftands at —69°. When it is paffed
through a red-hot porcelain tube, it is decompofed,
and converted into carbonic acid gas, carbonated hy¬
drogen gas, and wTater. 824
5. With the aid of heat, alcohol diffolves a fmall Phofphorus.
quantity of phofphorus. When this folution, which
has a foetid odour, is precipitated, by dropping a little
of it into w7ater, it becomes luminous in the dark.
There arife jets of flame from the furface of the w'ater j
and there is formed an oxide of phofphorus in the ftate
of white pow'der. Alcohol feems alfo capable of dif-
folving phofphorated hydrogen gas.
6. There is no a&ion between alcohol and fulphur, Sulphur,
neither at the ordinary temperature, nor even when
they are boiled together •, but when the two bodies
are brought in contact with each other in the ftate of
vapour, they combine readily, and there is formed a
foetid fulphurated alcohol, which depofits a fmall quan¬
tity of white fulphur, and becomes muddy in cooling.
The fulphur is precipitated by water, and gives about
■gVth part. Alcohol combines ftill more readily with
fulphurated hydrogen gas, w'hich communicates to
the alcohol a little colour, and in this combination
is decompofed with more facility by oxygen gas, and
all other Joxygenated bodies, than when it is in the
ftate
I
CHEMISTRY.
Inflam¬
mable fab.
ftances.
8 25
Of acids.
827
Of water.
Sa*
Alkalies
and falts.
ftate of gas. Alcohol combines with fulphurated hy¬
drogen gas, which is contained in mineral waters, and
, deprives them of this gas by diftillation.
7. The ftrong acids have a very powerful effe6t on
alcohol. It is decompofed by the fulphuric, the nitric,
the oxymuriatic, and the acetic acids; and the produft
of this decompofition varies according to the nature of
the acid, its ftrength, and the proportions in which it
is employed. Some of the acids are foluble in alcohol.
With the aid of heat, it diffolves the boracic acid,
which communicates to it the property of burning
with a green flame. It alfo holds in folution carbonic
acid gas in greater proportion than its own bulk. It
precipitates from water, on the contrary, the phofpho-
ric acid, almoft in the concrete ftate, and alfo the
metallic acids which are foluble in this liquid.
8 Alcohol combines with water in all proportions.
The affinity between the two fluids is fo ftrong that
water is capable of feparating from alcohol many
bodies with which it is combined, while the alcohol
decompofes many faline folutions, and precipitates the
fait. When water and alcohol are combined together,
there is an increafe of temperature, which fhews that
there is a condenfation of the two liquids. Accord¬
ingly it is found, that the denfity or fpecific gravity of
the mixture is greater than the mean of the uncombin¬
ed liquids. This denfity varies according to the dif¬
ferent proportions of the alcohol and water which are
employed. In confequence of this variation, it be¬
comes an objedl of confiderable importance to be able
to afcertain the ftrength of fpirits •, that is, the propor¬
tions of alcohol and water of different degrees of denfi¬
ty or fpecific gravity. This objedl is important, both
in a political and commercial view. For the purpofes
of commerce, various inftruments have been contrived,
and tables conftruffed, for the conveniency ofthofe who
are concerned in the purchafe and fale of fpirituous
liquors. For the purpofes of revenue, a moft elaborate
and minute fet of experiments was inftituted by Sir
Charles Blagden, who was exprefsly employed by the
Britifh government to afcertain the relative value or
ftrength of ardent fpirit at different temperatures and
different fpecific gravities. An account of thefe expe¬
riments was publifhed in the Philofophical Tranfadtians
for the year 1790. Tables which fhew the refult of
the experiments, were publifhed by Mr Gilpin in
1794; but as thefe are not immediately connedled
with the elements of chemiftry, we refer our readers
to the original papers, and to the article Spirituous
Liquors, in this work.
9. Alcohol diffolves the fixed alkalies in the pure
ftate, and forms with them an acrid folution of a red-
difh colour. The folution of potafh in alcohol was
formerly denominated the acrid tinBure of tartar. It
is in this way that the fixed alkalies are obtained in
their pureft ftate. Alcohol, therefore, becomes a va¬
luable inftrument of analyfis for feparating the fixed
alkalies from a great number of extraneous fubftances.
Ammonia alfo combines with alcohol by the affiftance
of heat. The ammonia with a higher temperature is
driven off, and carries wTith it part of the alcohol. Many
of the faline bodies may be diffolved in alcohol, and
on this account alfo it is valuable to the chemift in his
refearches. Tables have been conftrudled, (hewing
the quantity of different falts which may be diffolved at
543
different temperatures. The following tables were Inflam-
drawn up from the experiments of M. Guyton f.
I. Table of Salts which are readily Diffblved.
Tempe¬
rature.
240 grains of al¬
cohol diffolve at
54-5
54-5
54-5
54-5
54-5
H3-
180.5
< 180.5
180.5
180.5
Grains.
240
240
240
240
240
240
694
13*3
240
240
Nitrate of cobalt.
copper.
Muriate of zinc.
alumina.
Nitrate of alumina.
Acetate of lead.
Nitrate of magnefia.
Muriate
of iron,
of copper,
Nitrate of zinc de¬
compofed.
Nitrate of iron part¬
ly decompofed.
Nitrate of bifmuth,
* Jour, de
Phyjique,
I785>P- 5S-
II. Table of Salts that are little Soluble.
Grains.
240 grains of alco¬
hol at the boiling
temperature dif¬
folve
240
214
212
112
100
23
18
*7
9
7
5
5
4
1
Muriate of lime.
Nitrate of ammonia.
Oxymuriate of mercury.
Acetate of foda.
Nitrate of filver.
Nitrate of foda.
Acetate of copper.
Muriate of ammonia.
Arfeniate of potafh.
Superoxalate of potafh.
Nitrate of potafh.
Muriate of potafli.
Arfeniate of foda.
Tartrate of potafh.
III. Salts that are Infoluble,
Borax,
Tartar,
Alum,
Sulphate of ammonia,
iron,
copper,
zinc,
foda,
potafh,
lime,
filver,
mercury,
Tartrate of foda,
Nitrate of lead,
mercury,
Muriate of lead,
Carbonate of potafh,
foda.
The
544
Inflam¬
mable fub-
ilances.
C H E M I S T R Y.
The following table drawn up by Mr Kirwan, {hews alcohol of different denfities. The temperature In
the quantity of falts that are foluble in 100 parts of which the folutions were made was from 50 to 80 f. ftances#
Salts.
Sulphate of foda.
Sulphate of magnefia.
Nitrate of potafti.
Nitrate of foda.
Muriate of potaffi.
Muriate of foda.
Muriate of ammonia.
Muriate of magnefia
dried at 120°
}
Muriate of barytes.
Do. cryftallized.
Acetate of lime.
Alcohol of
0.900
o.
2.^6
10.5
0.872
0.848
0.834 0.817
o.
4.62
5.8
6.5
21.25
J:56
2.4
1.66
3 67
4-75
o.
o.
o.
0.38
0.38
'-5
23-75
0.29
o-43
4.12
36.25
0.185
0.32
.4-75
50.
0.09
0.06
4.88
f Min.
S29
Compofi-
tion.
830
Recording
to Lavoi-
. Tier.
83*
To Four-
, croy.
10. A great variety of different opinions have been
propofed with regard to the compofition of alcohol. It
had been obferved, in burning this combuftible fub-
ftance, in clofe veffels, that water was formed. Some
philofophers bad even obferved that the quantity of
water obtained by the combuftion of alcohol, was
greater than the whole weight of the alcohol which
wasconfumed. From obferving. this circumftance, it
was fuppofed to confift of water, combined with an
acid, an oil, or phlogifton, according to the views and
theories of different philolophers..
It is to the experiments of .Lavoifier that we are in¬
debted for afcertaining the real conftituent parts of
this fubftance. He burnt in a proper apparatus, with
a known quantity of oxygen gas., 76.7083 grs. troy of
alcohol, and after the combuftion, carbonic acid gas
and water were found to be the only produHs and by
eftimating the oxygen gas confirmed, the quantity of
carbonic acid and of water which were formed, it ap¬
peared that the quantity of alcohol confumed was com-
pofed of
22.840 carbone,
6.030 hydrogen,
47.830 water.
76.700
But it has been fince proved, by the experiments of
Fourcroy and Vauquelin, that oxygen is a component
part of alcohol for when they mixed together equal
parts of alcohol and concentrated fulphuric acid, and
while ether is formed from it, there was alfo at the
fame time a produdion of water the . alcohol in this
rafe was decoropofed, but the fulphuric acid fuftered
* Nichol
Jour. i.
p. Xgl.
no change. The oxygen, therefore, which combined
wdth the hydrogen in the formation of water, muft
have come from the alcohol *.
Sect. II. Of Ether.
By the a£bon of different acids wutfi alcohol, the Formation
latter is decompofed, and different produifts are obtain¬
ed, according to the proportions of the acid employed,
and the heat which is applied. When the acid and
the alkali are in a certain proportion, and are expofed
to a moderate temperature, the produft is a peculiar
fubftance which has received the name of ether. Ether ^
has been obtained by the aftion of different acids orj^ames,
alcohol, and hence it has received different names, as
fulphuric ether, nitric ether, muriatic ether. The firft,
namely the fulphuric ether, which feems to have been
long eft known, and is moft eafily obtained, has excit¬
ed the greateft attention among chemifts. We ftiall
therefore confider it firft.
I. Of Sulphuric Ether.
x. It appears from different paflages in the writings Hiftory.
of the earlier chemifts, that the knowledge of fulphu¬
ric ether was among their fecrets. It was then called
oleum vitrioli dulce. I he method of preparing it is
deferibed in a book publiftied at Nuremberg about
the Year ^54®* But the nature of this lubftance was
not much attended to till the year I73°> when a cer¬
tain quantity was prefented to the Royal Society by
Dr Frobenius, with, a paper which was publiftied in
their tranfa&ions for that year, containing an account
of a number of experiments which .were made upon
it.
Inflam¬
mable fub
itances.
txon.
SJS
Purifica¬
tion.
your- dt
Pbyf. xlvi.
P- 258.
C H E M
It. It was long known under the name of naphtha
among the German chemifts.
2. The following is the procefs by which fulphuric
ether may be obtained. Equal parts of concen-
■ trated fulphuric acid and alcohol are put into a re¬
tort, to which a receiver is to be adapted and luted.
Or perhaps it is better to add the acid by fmall por¬
tions at a time, that the a&ion may not be too violent,
and the heat produced too great. The receiver fhould
be immerfed in cold water, or furrounded with ice, or
it may be kept cool by the application of w>et cloths,
over which a fmall dream of water is directed. Pleat
is then applied, and the firft produft which comes over
is a fragrant fpirit of wine ; but as foon as the mixture
begins to boil, the ether comes over, is condenfed by the
cold, and runs in dreams down the Tides of the receh'er.
When the quantity obtained amounts to about one
half of the alcohol employed, the procefs diould be
flopped, and the receiver unluted and removed ; but if
it be continued, white fumes begin to come off, which
are knowm to be the fumes of fulphurous acid.
After this there rifes a light yellowifh coloured oil,
which has been called the fweet oil of wine. The heat
fhould now be moderated after the ether has paded
over, becaufe the matter contained in the retort be¬
comes black, thick, and fwells confiderably. When
the whole of the fweet oil has come over, there is dill
an evolution of fulphurous acid, which becomes thicker
and thicker, till at lad there is nothing but a dark
coloured fulphuric acid.
3. The ether which is obtained by this procefs is
impure. It is generally contaminated with fulphurous
acid. To purify it, it has been ufual to mix a quan¬
tity of potafh with the fluid, and to didil it over again.
The acid in this cafe combines with the potadi, and
the ether being feparated, paffes over into the receiver.
Dize, however, conddering this procefs as tedious and
uncertain, has propofed other fubdances in the room of
potafh, and he has tried feveral metallic oxides, fuch
as the red oxide of lead, the yellow oxide of iron, the
red oxide of mercury, and the oxide of manganefe.
But after a variety of experiments, he is of opinion,
that the black oxide of manganefe is the mod conve¬
nient for the purification of ether. It is mixed with
ether, allowed to remain fome time, and is to be fre¬
quently agitated. The oxygen of the manganefe
combines with the fulphurous acid, and converts it in¬
to fulphuric acid, which is a more fixed body than the
fulphurous acid *.
To feparate the liquid from the fulphurous acid,
Proud recommends the following method, which he
fays is employed in the large way, as by far the mod
preferable. Introduce into a bottle which is ^ths fil¬
led with impure ether, fome water, and a portion of
flacked lime. Agitate the bottle drongly, and do not
open it to examine its odour, till after it has remained
for fome minutes in cold water, and when the vapour
within the bottle has ceafed to exert its eladic force
againd the cork ; if the fulphurous fmell is not en¬
tirely removed, the procefs is to be repeated till it
is completely deflroyed. This method, which was em¬
ployed by Woulfe, Proud prefers on account of its
economy, particularly as it affords at the fame time a ful-
phite of lime, which is formed by the combination of the
fulphurous acid with the lime. When the liquids have
You V. Part II.
I S T R Y. 54i
feparated, the ether which fwims on the top, may be Inflam-
drawn off by means of a fyphon, and it may be intro- rn^*e fub~
duced into a retort to be rectified by didillation *. , al’ccs" ;
4. 1 he ether which is thus obtained, is a tranfparent 836
colourlefs fluid, of a very fragrant fmell, and a hot Properties,
pungent taffe. The fpecific gravity is only 0.7581, *^
fo that it is confiderably lighter than alcohol. It is xlu'
extremely volatile, fo that when it is agitated, or peur-^ ^
ed from one veffel to another, it is inflantly diflipated.
It produces fo great a degree of cold, that water may
be frozen by means of it. It rifes in the date of gas
which burns with great rapidity, and the air which
holds ether in folution may be palled through water
without being deprived of its combuflibility or fra¬
grance. _ . 837
5. It boils in the open air at the temperature of 98°, AA'on
and in the vacuum of an air-pump at—20°, fo that ithfc,at'
would conflantly remain in the date of gas if the pref-
fure of the air were removed.
When ether is kindled in the open air, it burns very
readily. The eleftric fpark alfo inflames it. It burns
with a copious white flame, and leaves behind it a
black trace on the furface of bodies expofed to the
flame. Lavoifier has obferved that there is always for¬
med an acid during the combudion of this liquid ; and
Scheele fays that the refiduum of ether burnt over a
little water, contains fulphuric acid. When the ether
is expofed to a cold of —46°, it freezes and cryflallizes.
It is decompofed when the vapour is paffed through a
red-hot porcelain tube, and the product is carbonated
hydrogen gas. 838
6. Dr Prieflley difcovered that ether agitated with T"creafes
any kind of gas, greatly increafed its volume, and in oftJfeLUmC
mod cafes doubled it. Mr Cruicklhank made a fimi-
lar experiment, by agitating fome oxygen gas with a
little ether. The bulk was exa£tly doubled. In this
date the gas did not explode, but when one part of this
mixture was added to three parts of oxygen, an ignited
body or the ele&ric fpark produced a dreadful explo-
fion. The products were water, with 2|d carbonic
acid gas. Hence it would appear, Mr Cruickfliank
obferves, that one part of this vapour requires about
feven of oxygen to faturate it; and according to this.
experiment, the proportion of carbone to hydrogen inya„^v°’
the vapour of ether or ether itfelf, Ihould be as five p. 205.
to one f. 839
7. Phofphorus is diffolved in fmall quantity in ether, ^<arIC>," of
and produces a tranfparent folution, but when alcohol 0mS*
is added to the folution, it becomes milky.
8. Sulphuric acid has a peculiar aftion on ether, by of
converting it into a kind of oil, which is called the fweet
oil of wine. This is one of the produffs in the preparation
of fulphuric ether. When a fmall quantity of ether is
introduced into a bottle filled with oxymuriatic acid
gas, it explodes, and inflames ; or if paper moidened
with ether be introduced, the fame effeff follows. Car¬
bonic acid gas is produced, and charcoal is depofited
on the fides of the bottle. 841
9. Various theories have been propofed, to account
for the produfhon of.ether. From the manner of itstl°n‘
produflion by means of fulphuric acid, it was natural to
fuppofe that this acid formed one of its component parts.
This accordingly became a general opinion, till it was
found that the fulphuric acid differed no change in the
procefs, but merely aflided or difpofed the alcohol to
3 Z that
;'4<5
C H E M
Inflam- that change which It undergoes when it is converted
mable fub- into ether. According to Macquer, the alcohol has
ftances- not been changed, but merely deprived of the whole of
' its water. Scheele fuppofed, that ether was alcohol
deprived of its phlogifton ; and when the new theories
were introduced, ether was confidered as & combina¬
tion of 'alcohol and oxygen. „ , r ^ ,
10. The experiments and refearches of Fourcroy and
Vauquelin have thrown new light on this fubjedl, and
have led to different views of the nature and compoij-
tion of ether. According to the refult of thefe experi¬
ments, ether contains a fmaller proportion of carbone,
but a greater proportion of hydrogen and oxygen.
From their experiments, and from thofe of others, it
appears that the changes induced by the adhon of iul-
. phuric acid on alcohol, depend on the quantity and
ftrength of the acid, and the temperature. _
s? Equal parts of concentrated fulphu'nc acid and
alcohol mixed together raife the temperature to 189^.
Bubbles of gas are emitted 5 the liquid becomes turbid,
and at the end of fome hours affumes a deep red co-
B. A mixture of two parts fulphuric acid, and one
part’alcohol, produces a temperature of 200°. The
mixture becomes inftantly of a deep red colour, pafles
to black a few days after, and diffufes an odour which
is perceptibly that of ether. < , . , .
C When equal parts of fulphuric acid and alcono
are expofed to the aftion of heat, in a proper appa¬
ratus, fuch as is employed for the preparation of ether,
the following phenomena are obfervcd. ^
a. When the temperature is raifed to 207 , the li¬
quid boils; there is produced a fluid which is conden-
fed by cold, into a light, colcurlefs and fragrant li¬
quor, which from its properties has received the name
of ether. If the procefs be properly conducted, no
permanent gas is evolved, till about ~ of the alcohol is
converted into ether. .
/? If as foon as the fulphurous acid appears, the re¬
ceiver be changed, there is no longer any produaion
of ether, but the fweet oil of wine, water, and acetic
acid are formed, without a Angle particle of carbonic
acid. When the fulphuric acid makes about 3 ths of
the mafs which remains in the retort, there is evolved
an inflammable gas, which has the odour of ether, and
which burns with a white oily flame. I his is the gas
which the Dutch chemifls have called carbonated hy¬
drogen gas, or olefiant gas,^ becaufe when it is mixed
with oxymuriatic acid it forms oil.. At.this period,
the temperature of the matter contained in the retort
is elevated to 230° or 2 3 40. > . „
c. When the fweet oil of wine ceaies to flow’, it the
receiver be again changed, there is only fulphurous
acid emitted, water which was previoufi.y formed, car¬
bonic acid gas *, and there remains only m the retort, a
mafs which confifts chiefly of fulphuric acid thickened
with charcoal.
From thefe phenomena, which were uniform and con-
ftant, the following conclufions w^ere drawn.
a;A ffnall quantity of ether is formed fpontaneoufly
without the aid of heat, by the combination of two
parts of fulphuric acid and one part of alcohol..
b. As foon as the ether is formed, and there is at the
fame time a produftion of wster, the fulpi. jric acid un*
Inflam¬
mable fub-
fiances.
&41
>nlerences,
I S T R Y.
dergoes no change in its intimate nature, while the nrfi:
of thefe compofitions takes place.
c. When the fulphurous acid appears, there is no
longer any produ&ion of ether j but then there pafs
over the fweet oil of wine, water, and acetic acid.
d. The fweet oil of wine having ceafed to pals over,
nothing is obtained but fulphurous acid, carbonic acid,
and at laft fulphur, if the diftillation be continued.
The operation of ether, then, may be divided into
three periods, the firft, in which a imall quantity of
ether and water is formed, without the afliltance or
heat; the fecond period, in which the greateil quanti¬
ty of ether which can be obtained without the evolu¬
tion of fulphurous acid at a temperature of 207° j and
the third, in which the fweet oil of wine, oleflant gas,
acetic acid, fulphurous and carbonic acid are produc ed^,
while the temperature of the mixture is raifed to 2 30
and 2 340. In all thefe three periods there, is only one
common circumitance, and this is, the continual forma¬
tion of water from the beginning to the end of the ope-
ration. , _T , 843
On thefe obfervations, Fourcroy and Yauquelin have xheory.
eflablifned their theory of the formation of ether. In
the cafe in which ether is formed by the Ample mix¬
ture of alcohol and fulphuric acid, without the aid ot
heat, the formation which appears by heat as well as
by the black precipitate, the charcoal which is feparat-
ed without the production of fulphurous acid, prove
that the fulphuric acid afts in a different manner on
alcohol from what was fuppofed. This acid is not de-
compofed by charcoal at that temperature. 1 here is no
aftion between thefe twTo bodies in the cold, nor is there
any aClion between this acid and alcohol; for in that
cafe, fulphurous acid would be formed, of which not
the fmalleft trace can be perceived at the beginning of
the operation. Recourfe then muft be had to a dif¬
ferent aCfion, namely the ftrong affinity which exifts
between fulphuric acid and w’ater. It is this which de¬
termines the union of the conftituent principles of wa¬
ter exifting in the alcohol, and with which this acid
comes in contaft but this a&ion muft be very limited.
There is focn eftablifhed a balance of affinities, and no
farther change takes place. . j i. v
If then it be proved that ether is formed by the
mixture of certain quantities of fulphuric acid ^d al¬
cohol it muft obvioufly follow, that a mafs of alcohol
may be completely converted into ether, water and
acetic acid, by increaftng the quantity of fulphuric
acid and it is equally obvious, that this acid would
undergoes no change but that of being diluted with
w’ater. 1 • ,1
It is not necefiary to fuppofe, according to this theo¬
ry that ether is alcohol deprived of a certain portion
of oxygen and hydrogen, for there is feparated at the
fame "time a quantity of charcoal proportionally greater
than that of the hydrogen 5 and it may be conceived,
that the oxygen which is combined in this cafe with the
hydrogen, to form water, would not only faturate this
hydrogen in the alcohol, but that it would fatur.ate at
the fame time the carbone which has been precipitated.
Thus then, in place of conftdermg ether as alcohol
with ’a fmaller proportion of hydrogen and oxygen,
if we take into account the carbone which is precipitat¬
ed, and the fmall quantity of hydrogen contained m
J the
C H E M I S T R Y.
Inflam- tlie water tliat is formed, it inufl: he confidered as al-
raabie fub- cohol with a greater proportion of hydrogen and oxy-
ftances. gen> Such ieems to be the nature of the fpontaneous
action between fulphuric acid and alcohol without the
aid of heat.
But when the mixture is fubjefled to heat, the pro¬
duction of ether is more complicated, and the produCls
more numerous.
It ought to be obferved, that the mixture of fulphu¬
ric acid and alcohol in equal proportions, boils only at
the temperature of 207°, whilft alcohol alone boils at
176° j whence ive mult conclude, that the alcohol is
retained by the affinity of the fulphuric acid, which
fixes it. Now', if we compare what happens in this
cafe to the change produced on all other vegetable
matter expofed to the aftion of heat, in which the
principles are volatilized, according to the order of
their affinity for caloric, carrying with them a fmall
quantity of the more fixed elements, in proportion as
the fulphuric acid attrafts the alcohol and the vcater,
of which it favours the formation, the ether which is
evolved attrafls caloric, and is fublimed *, and when
the greateft part of the alcohol has been changed into
ether, the mixture becomes denfer, the heat more
confiderable, and the affinity of the fulphuric acid for
the undecompofed alcohol being increafed, the acid is
decompofed, fo that on one hand its oxygen combines
with the hydrogen of the alcohol, and forms water,
which rifes gradually into vapour, whilft, on the other,
the ether retaining a greater quantity of carbone, with
•which it rifes in vapours at this temperature, affords
the fweet oil of wine, which ought to be confidered as
an ether with a greater proportion of carbone. This
feems to be proved by its greater fpecific gravity, lefs
volatility, and its citron colour.
11. From this theory the ingenious authors of it
have deduced the following praftical conclufions.
a. The formation of ether is not owing, as was fup-
pofed, to the immediate aftion of the principles of the
fulphuric acid on thofe of alcohol, but to the reaction
of the principles of the latter on each other, and par¬
ticularly of its oxygen and hydrogen, occafioned by
the fulphuric acid.
b. A portion of alcohol may be converted into ether
without the aid of heat, by increafing fufficiently the
proportion of fulphuric acid.
c. With regard to the change which takes place on
alcohol in the produflion of ether, the procefs may
be divided into twm periods. In the one, ether and
water only are produced $ in the other, fweet oil of
wine, water, and fulphuric acid.
d. During the formation of ether, the fulphuric acid
is not decompofed, and there is no production of the
fweet oil of wine. When the latter makes its appear¬
ance, there is given out no more, or at leaft very lit¬
tle, ether *, and at the fame time the fulphuric acid is
decompofed by hydrogen folely, whence fulphurous
acid is formed.
e. The formation of the fweet oil of wine may be
avoided, by keeping-the temperature of the mixture be¬
tween 200° and 207°. This is managed by introdu¬
cing a few drops of water into the retort.
f And laftly, alcohol differs from ether, in con¬
taining more carbone, lefs hydrogen and oxygen, and
547
the fweet oil of wine is to ether very near what alcohol Inflam- '
is to the latter *. “ftancS!"'
II. Of Nitric Ether. *~Four~rcy
1. Nitric acid, or rather nitrous acid, a£ts with
much greater violence on alcohol than fulphuric acid. Chm. tom.
In this cafe the action muft be moderated, either by ^^5. ’
diluting the two liquids, or by cooling the mixture.
The firft eafy procefs which was propofed for the pre¬
paration of nitric ether, was given by Navier, a phyfi-
cian of Chalons. 844
2. The procefs of Navier is the following. He
put into a ftrong bottle 12 parts of pure alcohol, and y
plunged it into cold water, or rather furrounded it
with ice. To this he added, in different portions,
eight parts of concentrated nitric acid, agitating the
mixture, after every addition. The bottle is then
flopped with a cork, which is fecured with leather,
and the mixture is fet in a convenient place, to avoid
the danger of accidents on the burfting of the bottle,
which fometimes happens. At the end of fome hours,
bubbles rife from the bottom of the veffel, and drops
are collected on the furface of the liquid, which gra¬
dually form a ftratum of ether. This a&ion continues
for the fpace of fix days. When it ceafes, the cork is
to be pierced with a needle, to permit the efcape of a
quantity of nitrous gas, which, without this precau¬
tion, would rulh out rapidly on uncorking the bottle,
and would carry along with it the ether, which would
be loft. When the gas is diffipated, the cork is to be
drawn out, and the whole liquid in the bottle is to be
poured into a funnel. The ether fwims on the top,
and the remaining liquor being, heavier, is allowed to
pafs off, and the ether is retained. ^ g45
3. This procefs was improved by Beaume. He Eeaunad.
found that the greateft produce of ether was from two
parts of acid to three of alcohol. He directed both
ingredients to be ufed in the coldeft ftate, by keeping
each in melting ice, and the bottle in which the mix¬
ture is made, to be kept equally cold. In this propor¬
tion of ingredients, the danger of explofion is avoid¬
ed, and the low temperature greatly moderates the
violent aftion. The mixture in the bottle is always .
to be well agitated before any new addition of acid is
made, and by this means the accumulation in any par¬
ticular fpot is prevented. The ether begins to form,
as in the former procefs, in the couife of a few hours,
and if the bottle is allowed to remain undifturbed for
eight or ten days, a quantity of ether equal to one
half the weight of the alcohol is obtained, after which
no more is produced. g4(j
4. Dr Black’s procefs is deferibed by himfelf in the Black’s
following words. “ Into a ftrong phial, having a procefs.
ground ftopper, I firft pour four ounces of ftrong,hale
nitric acid. I then add three ounces of water, pouring
it in fo gently, that it fwims on the furface of the acid.
I then pour in after the fame manner fix ounces of al¬
cohol. I put in the ftopper (lightly, and I fet the
phial in a tub of water and ice. The acid mixes (low¬
ly with the water, and in a diluted ftate comes in con¬
tact with the alcohol on which it immediately ads,
and ether is produced (lowly and quietly. The liquor
gets a dim appearance, becaufe imperceptible bubbles
are formed, which get to the top, and having colleft-
3 Z 2
* Black's
Left. ii.
324-
847
Laplanche’s
Fourcrey
Connaijs.
Chim. tom.
via, p. 170.
848
Chaptal’s.
C H E M
ed to a certain degree, they lift the Hopper, and
efcape (s). After eight or ten days I find upwards of
three ounces of nitric ether, though I am certain by
the fmell, that much efcapes with the vapour. This
is however, a certain, eafy, and fafe procefs, though it
is flow and imperfect*.”
5. Many other proceiTes have been propofed for the
preparation of nitric ether. Laplanche, a Parifian
apothecary, has employed nitre, which he introduced
into a tubulated ftone-ware retort, and firft pouring
the concentrated fulphuric acid, and then the alcohol
upon it, there is an immediate produflion of ether ;
but by this procefs it is fufpe&ed that the nitric ether
may be mixed with fulphuric ether. He has therefore
propofed another procels, which is more complicated •!•.
6. The procefs which has been propofed by Chap-
tal, is, according to Prouft, the belt that can be adopt¬
ed. This procefs, with fome additions and altera¬
tions, which he has found it neceffary to make from
his own experience, is the following. 1 he proportions
which he employs are, 32 ounces of alcohol, and 24
of nitric acid. Thefe are introduced into a large re¬
tort, which is to be luted to a globular glafs veflel,
furniflied with a tube of fafety. A tube pafles from
this globe to a fecond, which is alfo furnilhed with a
tube of fafety. One or two ounces of water fliould
be introduced into the fecond globe to flrut up its tube
of fafety. Three bottles of Woulfe’s apparatus, con¬
taining from 64 to 80 ounces of liquid, are then to be
connefled with the fecond globe. Thefe bottles are
half filled with alcohol. The alcohol and the acid
are poured into the retort, and are mixed by agitation.
The retort is luted to the glafs globe, and heat is ap¬
plied, with this precaution, that it mull be removed
as foon as there is any effervefcence. The procefs
now goes on, and requires no farther attention than oc-
cafionally cooling the globes and the bottles with
cloths moiftened with fnow-water. The greateft part
of the ether which is formed, condenfes in the firft bot¬
tle, and gives the alcohol a yellow colour.^ It then
paffes to the fecond, in which the colour is lighter,
and at laft to the third, where there is little percepti¬
ble change. To feparate the ether of the firft bottle,
the mixture is to be faturated with an alkali, and dif-
tilled J.
7. But by whatever procefs nitric ether is obtained,
it requires to be purified, to feparate the acid and al¬
cohol, which are generally mixed with it. This is
done by diftilling it from potaftr, which reduces its
quantity, for the diftillation muft not be continued
longer than when two-thirds or one-half of the firft
ether has come over. To purify this ftill more, it is
direfted to be mixed with one-fifth of nitrous acid, and
diftilled again, taking two-thirds of the product fet
apart, and rectify it from an alkali. The remainder
which comes over is a lefs pure ether, which has been
known under the name of Hoffman's mineral anodyne
liquor. What remains in the retort has been called
gSo dulcified fpirit of nitre.
Properties. 8. Nitric ether thus obtained, is a yellowiftr colour-
t Ann. de
Cbim. tom.
slii. p. 261.
S49
Purifica¬
tion.
I S T R Y.
ed liquid, equally volatile as fulphuric ether. Its
odour, though ftronger and lefs fweet, is analogous to
the fulphuric ether. The tafte is hot and more difa- ■ ——1
greeable. It is often of a deeper yellow colour, and
always contains a fmall excefs of acid and nitrous gas.
The Hopper is frequently driven out of the bottle in
which it is kept, for there is a conftant evolution of a
confiderable quantity of gas. _ 851
9. When it is fet fire to, it gives out a more bril- Burns with
liant flame, and a denfer fmoke, than fulphuric ether j unt
and it depofits a greater quantity of charcoal. When
it is long kept in a clofe veflel, there is formed fome
water, holding a fmall quantity of oxalic acid in folu-
tion, which falls to the bottom of the veffel. 85*
10. Nitric ether is not only analogous to fulphuric Analogous
ether in its properties, but alfo in the nature of the ^^hunC
procefs by which it is obtained, and in the other pro-
dubls wThich accompany this procefs. But in the pro-
du&ion of nitric ether, there is no depofition of char¬
coal, and the acid itfelf is decompofed. This appears
from the great quantity of nitrous gas which is evol¬
ved during the procefs j and the reafon afligned for the
difappearance of the charcoal is, that the oxygen of
the acid combines with it, and forms carbonic acid,
which efcapes in the form of gas. The produdls
which are generally obtained in the proceffes for the
preparation of nitric ether are nitrous gas, ether, oil,
acetic acid, oxalic acid, and carbonic acid gas.
If equal parts of nitric acid and alcohol are mixed to¬
gether, a violent effervefcence immediately takes place,
which is owing to the evolution of a great quantity of gas,
which being a compound of ether and nitrous gas, has
been denominated etherifed nitrous gas. 1’he fame gas
is obtained by employing a diluted acid j but then the
mixture requires the afliftance of heat. This gas may
be collefted in veffels over water. It has a difagree-
able ethereal odour, quite different from the odour of
nitric ether, and exaftly fimilar to that kind of ether
which is furniflied by the oily, carbonated hydrogen
gas, treated with oxymuriatic acid gas. If a candle
be applied to this gas, it burns flowly with a yellow
flame. This gas is foluble in wrater, and is wholly ab-
forbed } but the abforption is flow. The water ac¬
quires the odour of the gas. Alcohol alfo diffolves it
completely, and more rapidly. Oxygen gas mixed
with this gas, provided it be pure, produces no change j
but when the mixture is fet fire to, there is a violent
detonation. When this gas was expofed to fulphuric,
nitric, and muriatic acids, the ether was abforbed by
the acids, and the nitrous gas remained behind. The
fulphurous acid in the Hate of gas, combined with an
equal bulk of the inflammable gas, alfo decompofed it j
but this effefl did not take place till after feveral
days *. . * your. d»
If the alcohol and nitric acid be mixed together in Pbyf
the proportion of one of the former to three of the lat-P- 24S-
ter, and a gentle heat be applied, there is a copious
evolution of gas, which is compoled of the etherifed
nitrous gas and nitrous gas. If towards the end of the
procefs, when a fmall part of the liquid remains in the
retort,.
(s) Hr Black, we believe, contrived a fpring for the ftopper which kept down the cork till it was pulhed uj)
by the elaftic vapours j and when they had efcaped, it returned to its place by the force of the fpring.
Inflam¬
mable fub-
ftances.
* ’Jour, de
Fbyfiqu'y
p. 346.
8 S3. r
Proceflesfor
obtaining
^ 8s4-,
From lalts
ef tin.
Purifica¬
tion.
G H E M
retort, it be allowed to cool, cryftals are formed ; and
thefe cryftals are found to be oxalic acid. They were
formerly called cryflals of Hierne, from the name of a
Swedilh chemift, who firft difcovered them *.
If one part of nitric acid be added to its own weight
of alcohol, and one part of fulphuric acid be added
foon after, the mixture is fuddenly inflamed, and burns
with great violence. In this cafe, when the pro-
du£ts are collected, they are found to be ether and
oil.
From this ftatement of fa&s, therefore, it appears,
that the production of nitric and fulphuric ethers is near¬
ly the fame j that the differences which take place, are
owing to the different nature of the acids \ the violent
aftion which follows in the formation of nitric ether,
depending on the nitric acid itfelf being decompof-
ed, and by the operation of new affinities, new aCtions
having taken place.
III. Of Muriatic Ether.
1. Muriatic acid has no fenfible aCtion on alcohol,
either by Ample mixture, or by diftillir.g them toge¬
ther, as in the former cafe. Beaume obtained a fmall
quantity of muriatic ether, by combining together mu¬
riatic acid and alcohol in the ftate of vapour. But
other means were thought of for this purpofe, and par¬
ticularly the oxymuriate of antimony, and the oxide
of zinc diffolved in muriatic acid, and to diftil this
fait, concentrated by evaporation, in clofe veffels with
alcohol. By this procels muriatic ether has been ob¬
tained. But the molt fuccefsful method of procuring
this ether, was propofed by Courtanvaux. His procefs
is the following.
2. One part of alcohol is mixed with three parts of
oxymuriate of tin, or the fuming liquor of Libavius,
in a glafs retort. A ftrong heat is produced, with
the produflion of a white fuffocating vapour, which
difappears when the mixture is agitated. There is
then emitted an agreeable odour, and the liquor af-
fumes a lemon colour. The retort is then to be placed
on a fand bath •, twm receivers are to be attached, one
of which is to be immerfed in cold water. There
paffes over at firft fome pure alcohol, and foon after
the ether, which is known by its fragrant oddui, and the
ft reams which run down the fides of the retort. When
the odour changes, and becomes (harp and fuffocating,
the receiver muft be changed 5 and if the diftillation
be continued, a clear acid liquor is procured, on the
furface of which are obferved fome drops of fweet oil,
which is fucceeded by a yellow matter of the confift-
ence of butter, which is a true muriate of tin, and at
laft a brown heavy liquid, which exhales very copi¬
ous white vapours ; and there remains in the retort a
gray matter in the ftate of pov'der.
3. To purify this ether, it is put into a retort over
carbonate of potaffi. A brilk effervefcence takes place,
and a very copious precipitate is produced. This is
owing to the oxide of tin wffiich the acid had carried
off during the diftillation. A little water is to be ad¬
ded, and diftilled with a gentle heat. About the one-*
half of the produfl of the ether is thus obtained. All
the fluids which come over after the muriatic ether,
are loaded with oxide of tin ; they attract moifture
from the air, and combine with the water without any
precipitation.
I S T R Y.
545
4. Another method has been prcpofed for the pre- Inflam-
paration of muriated ether by Laplanche. He pours m^e
into a tubulated retort fulphuric acid and alcohol on ^ .
common fait which has been ftrongly dried. The mu-
riatic acid gas, difengaged by the fulphuric acid, Prepared
meeting the vapours of the alcohol in the retort, com-f10m com¬
bines with them. In this way an ether is obtained,mon lt
which may be purified in the ufual way. But in this
procefs, Fourcroy thinks, that the produftion of ether
is owing to a fmall portion of oxymuriatic acid which
is formed during the procefs. 857
5. Pelletier has fucceeded in obtaining muriatic manga-
ether, by diftilling in a large tubulated retort, a mix-11 '*
ture of oxide of manganefe, common fait, concentrat¬
ed fulphuric acid, and alcohol. The quantity of ether
obtained by this procefs, is equal to one half the
weight of the alcohol employed. S5S
6. Another procefs has been propofed by Berthol- and oxy-
let, by diftilling with a gentle heat, alcohol which muriatic
has been faturated with oxymuriatic acid gas, and by‘lL:“ s“ ’
diftilling the oxide of manganefe, a mixture of alcohol,
and ftrongly concentrated muriatic acid. 859
7. Muriatic ether thus obtained, is tranfparent and Properuer,
very volatile. It has nearly the fame odour as fulphu¬
ric ether. It burns like it, and gives out a fimilar
fmoke *, but it differs in two of its properties j the one
is, that it exhales, wffiile burning, an odour as pun¬
gent and acrid as fulphurous acid *, and the other
is, that the tafte is aftringent like that of alum. 1 his
difference in odour and tafte is owing, it is fuppofed,
to fome extraneous fubftances writh which it is conta¬
minated ; for in the whole procefs of its formation it
appears to be exactly the fame j a conftant product of
the decompofition of alcohol, by whatever re-agent this
is effeaed.
IV. Acetic Ether.
1. An ether has alfo been obtained by diftilling a prepara„
mixture of acetic acid and alcohol. 'Iliis wras the firft tion.
procefs which was employed in the produaion of this
ether. It wras difcovered by the count de Lauraguais
in 1759. It has been improved by Pelletier, who di-
ftillecl equal quantities of acetic acid, obtained from
acetate of copper, and alcohol. It was then poured
back into the retort, and diftilled a fecond time.
When this procefs is finiftied, it is diftilled a third
time, and the produa of the third diftillation is a
mixture of acetic acid and ether. To feparate the acid
from the ether, it isTaturated with potafh, and diftil¬
led with a gentle heat. The acetic ether paffes over
in a ftate of purity.
2. Another procefs has been propofed to obtain the
fame ether. Take 16 parts of acetate of lead, fix
parts of concentrated fulphuric acid, and nine parts of
alcohol. Let it be diftilled till ten parts come over.
Let this liquid be agitated with one-third of its bulk
of lime water 5 the ether feparates and fwims on the
top. The quantity generally amounts to about fix
parts.
3. This ether is fimilar to the other ethers in its
properties, excepting that it has a flight odour of ace¬
tic acid.
4. Ether has alfo been formed by feveral other
acids, and it appears, that thefe acids poffefs one com¬
mon property in their aftion on alcohol, for all the
ethers
55°
Inflam¬
mable fub-
ftances.
8 (Si
Oils of two
kinds.
862
Found only
in the feed
of vegeta¬
bles.
Fjurcrcy
Connaifs.
vii. 319.
803
Have dif¬
ferent pro¬
perties.
C H E M
ethers produced by the different acids are nearly the
fame, and indeed it is fuppofed would be exactly the
fame, were it not that they are contaminated with ex¬
traneous matters derived from the acids, the alcohol,
or other fubftances, which are employed in their for¬
mation.
Sect. III. Of Fixed Oils.
1. Oils, which are copious productions of nature,
have been long known ; and their extenfive utility in
domeltic economy and the arts, have always rendered
them objeCts of great importance. The general cha¬
racters of oils are combuftibility, infolubility in water,
and fluidity. From the peculiar properties of different
oils, they are naturally divided into two kinds 5 fixed
or fat oils, and volatile or effential oils. The fixed
or fat oils, require a high temperature to raife them to
the ftate of vapour, a temperature above that of boil¬
ing water ; but the volatile or eflential oils are volati¬
lized at the temperature of boiling water, and even at
a lower one. Both the volatile and fixed oils are ob¬
tained from plants, and fometimes from the fame plant,
but always from different parts of it. While the feeds
yield fixed oil, the volatile oil is extraded from the
bark or wood.
2. One of the moft diftinguilhing charaCleriftics of
the fixed oils is, that they exift only in one part of the
vegetable. Thev are only found in the feeds. No
trace of fixed oil can be deteCled in the roots, the
ilem, leaves or flowers of thofe plants, whofe feeds af¬
ford it in great abundance. The olive may leem an
exception to this. The oil which it yields is extract¬
ed, not from the feed, but from its covering. Among
plants too, fixed oils are only found exifting in thole
whofe feeds have a peculiar ftruCture. I he feeds of
plants have fometimes one lobe, in which cafe they
are called monocotyledonous plants •, and fometimes they
have two, ivhen they are denominated dicotyledonous.
The formation of fixed oil in plants is exclufively li¬
mited to the latter clafs. There is no inftance of fix¬
ed oils being found in the feeds of plants which have
only one lobe *. Thofe feeds which yield the fixed
oils, contain alfo a confiderable portion of mucilage,
fo that when fuch feeds are bruifed and mixed with
water, they form what is called an emulfion% which is
a w’hite fluid containing a quantity of the oil of the
feed mixed with the mucilage. One of the moft com¬
mon emuliions, that of almonds, is an inftance of this.
Fixed oils are extrafted from the feeds of a great
number of plants. Thofe which yield it in greateft
abundance are, the olive, thence called ohve oil; the
feeds of lint, and the kernels of almonds, called hnfeed,
or almond oil. Fixed oils are alfo obtained from ani¬
mals, fuch as train oil, as it is called, which is extracted
from the fat or blubber of the whale. Fixed oil is obtain¬
ed alio in great abundance from the liver of animals,
and is found to exift in the eggs of fowls.
3. Thefe different kinds of fixed oils, although they
poffefs many common properties, yet in others they
are very different. Many of the vegetable oils have
no fmell, and fcarcely any perceptible tafte. The ani¬
mal oils, on the contrary, are generally extremely
naufeous and offenfive. Thefe differences are fuppofed
I S T R Y.
to be owing to the mixture of extraneous bodies, or to Inflatn-
certain chemical changes which arife from the a&ion
of thefe bodies upon each other, or on the oil itfelf. .
4. As the fixed oils exift ready formed in the feeds
of plants, they are generally obtained by exprejjion, and Prepara-
hence they have been called exprtjfed oils. This istion.
done by reducing the feeds to a kind of pulp, or pafte,
which is inclofed in bags, and fubjeCled by means of
machinery, when it is obtained in the large w7ay, to
ftrong preffure, fo that the oil flows out, and is eafily
colleCled. The oil which is obtained by this procefs,
which has been called cold-drawn oil, becaufe it is
procured without the application of heat, and merely
by preffure, is the pureft j but the quantity which feeds
in general yield is comparatively fmall, and fome feeds
which contain a confiderable portion of oil, fcarcely
afford any when treated in this way. It therefore be¬
comes neceffary for extracting the oil from feeds of the
latter defeription, and to have it in greater abundance
from all feeds, to employ beat, to facilitate the repara¬
tion of the oil from the mucilage or other matters
with which it is combined. For this purpofe heat is
applied, either to the apparatus which is employed in
preffing out the oil, or the bruifed feeds are expofed to
the vapour of water, and fometimes they are boiled in
the w'ater itfelf, by w'hich means thofe fubftances
which are foluble in water, are feparated, and thus
the oily part which adhered to thefe fubftances, is dif-
engaged. ... S55
5. The oils which are obtained in this way are very Purifica-
impure. They are mixed wuth mucilage, and othert10n*
parts of the fubftances from which they have been ex¬
tracted. Many of thtfe matters feparate from the oils
when they are left at reft. They are fornetimes me¬
chanically purified by filtration through coarfe cloths,
by which means the groffer parts are feparated. Dif¬
ferent oils too, it is laid, undergo different kinds of
purification by different manufacturers, but thefe pro-
ceffes are kept fecret. After they have remained at
reft for fome time, they are filtered and agitated with
water, by which the parts that are foluble in this fluid
are feparated from the oil. Sometimes they are gent¬
ly heated, for a ihorter or longer time, according to
the nature of the fubftances with which the oil is con¬
taminated. Acids diluted with water are employed
to feparate the mucilage ; lime and the alkalies are
alfo ufed to combine with an acid which holds this
mucilage in folution, and thus to favour its precipita¬
tion. Alum, chalk, clay, and afhes, are alfo em¬
ployed in the purification of oils. _
6. Fixed oils are generally liquid, but of a thick, propertIe^
vifeid confiftence. They are mild or infipid to the
tafte ; fometimes, however, they have a peculiar tafte,
which is analogous to that of the plant from which
they have been extraCled. When pure, they have no
fmell, but are fometimes impregnated with the odour
of the feed which produces them. The fixed oils are
rarely quite colourlefs, but are generally green or yel-
lowifh. If they are green when frefti prepared, this
colour changes to a yellow, and in time to an orange
or red. Fixed oils in general are lighter than water.
The fpecific gravity varies from o.pifS? which is that
of olive oil, to 0.9403, that of linfeed oil. The boil¬
ing point of the fixed oils is not under the temperature
£
ftances.
867
Action of
heat.
C H E M
Inflam- of 6oo0. When expofed to cold, they congeal, and
triable fub- even cryftallize. There is, however, a confiderable va-
^ riety in this refpeft, among fixed oils : fome become
folid at the temperature of a few degrees above the
freezing point of water •, while others on the contrary
require a degree of cold =5°j and fome remain fluid
when expofed to the greatelt cold. Thofe oils, it has
been obferved, which moft readily become folid, fuch
'as olive oil, are leaft; fubjeft to change ", while thofe
which congeal with difficulty have a greater tendency
to fpoil and become rancid.
•7. When fixed oil is expofed to heat, it does not
evaporate, till it is raifed to the temperature of boil¬
ing, or 6oo°; but wflien it is thus raifed in vapour its
properties are changed. It is decompofed by the fe-
paration of fome of its principles. The part that is
volatilized has a greater proportion of hydrogen ;
charcoal is depofited, and water and febacic acid are
formed, while carbonated hydrogen gas is difengaged.
By this diftillation an oil was produced, denominated
by the older chemifts, philofophicol oil.
When oil is expofed to the open air, and a burning
body is brought in contact with it, it readily takes
fire, and burns rapidly, with a yellowifli white flame.
It is on this converfion of oil into vapour, and the in¬
flammation of this vapour, that the application of oil
in lamps and candles, depends. The oil is gradually
and in fmall quantities brought in contaft with the
burning part of the wick; it is converted into vapour,
which is immediately inflamed, and continues to burn
till new portions are fupplied to undergo the fame
change, and thus keep up a conftant and uniform light
and heat.
8. According to the analyfis of olive oil by La-
voifier, it is compofed of hydrogen and carbone. In
the experiment which he inflituted to afcertain its com¬
ponent parts, he burnt
oil 15.79 grs. troy,
oxygen gas 50.86
868
Compofi-
tion.
66.61
I S T R Y.
The component parts,
olive oil are
therefore, of 100 grains
551
of Inflam¬
mable fub-
ftances.
The produ&s of this combuftion were water and car¬
bonic acid. The weight of the water could not be af-
certained with much precifion, but the quantity of car¬
bonic acid which was formed, amounted to 44.50 grs.
This quantity fubtra&ed from the whole weight of
the fubftances confirmed, namely the oil and oxygen
gas, left 22.15 grs. for the weight of the water. The
proportion of oxygen in this quantity of water is
18.82 grs. which leaves 3.33 grs. of hydrogen, the
other component part. The proportion of oxygen in
44.50 grs. carbonic acid gas is 32.04 grs. which leaves
12.46 of carbone. The oxygen of the water and of
the carbonic acid, namely 18.82 grs. of the one, with
32.04 Srs' °^er) mahe up the whole quantity of
oxygen, namely ^0.86 grs. that was confirmed. From
this analyfis, therefore, 15.79 of olive oil are compofed
of
12.46 carbone,
3.33 hydrogen.
78.92 carbone,
21.08 hydrogen.
100.00
869
When it is Infoiublein
15-72
9. The fixed oils are infoluble in water,
neceflary to combine them with this liquid, it is by means water-
of mucilaginous fubftances, in which cale the mixture
is known under the name of emulfon, or with alkaline
fubftances, when it is diftinguiffied by the name of
foap. _ ®.7° f
10. When fixed oils are expofed to the air, they un- A<nion
dergo peculiar changes; and thefe changes are different,
according to the nature of the oil.
11. Some of thefe oils become thick, opaque, white,
granulated, and are analogous in appearance to tallow.
Oilsfubjecl to this change are called oils, fuch, for
inftance, is olive oil, almond oil, and rapefeed oil.
This change is more or lefs rapid in different circum-
ftances. If a thin layer of oil be fpread on the furface
of water, and expofed to the air, it takes place in a few
days, and this effeft is owing to the abforption of oxy¬
gen, wffiich combines with the oils. It was fuppofed
by Berthollet, that it depended on the aflion of light,
but his experiments were repeated by Senebier, who ^ ^ ^
found that olive oil when kept in the dark, became An^
rancid, w-bile the fame kind of oil expofed to ^chim.xi.
light, but excluded from the air, remained unchan-91.
ged *. 87r .,
„ 12. But other oils, when they are expofed to the DryinS °U3-
air, dry altogether, yet have the property of retaining
their tranfparency. Oils which have this peculiar pro¬
perty are called drying oils. The oil of poppies, hemp-
feed oil, and particularly linfeed oil, are poffefled of
this property. The nature of the change which takes
place in thefe drying oils, is fuppofed to depend on the
abforption of oxygen ; and this oxygen combining with
the hydrogen of the oil forms water. This opinion is
fupported by the pradtice which is followed to increafe
the drying property of linfeed oil. It is ufually boiled
with litharge, before^t is employed by painters. The
litharge in this cafe is partly reduced to the me¬
tallic ftate, by being deprived of its oxygen, which is
fuppofed to combine with the oil. S72
13. But many of the fixed oils, when expofed to the Rancidky'
air for a fufficient length of time, undergo a farther
change, and acquire very different properties. They
are then faid to become rancid. During this change,
they affume a brown colour, have the property of
changing vegetable blues to red, and acquire a peculi¬
ar fmell and tafte. In this change, the febacic acid is
formed, which depends on a new cornbination of the:
hydrogen and carbone of the oil in certain proportions
with the oxygen abforbed from the atmofphere. q-0t
this acid therefore, the rancidity of oils feems to be
owing. Part of the hydrogen of the oil too, it would 328.
appear, combines with the oxygen and forms water f. 873
14. Carbone in the ftate of charcoal, has no adfiion A<fti0n of
upon oils ; but they are purified and rendered colour-chaic0d1'
lefs by being paffed through charcoal powder. g74
15. Phofphorus combines with oils, with the affift-Qfphofpho-
auce of heat. A ftnall portion of the phofphorus is dif- rus.
folved.
552
Inflam-
qjable fub-
vflances.
CHEMISTRY.
S75
Of fulphur.
^ Fcurcroy
Connaifs.
Chim, vii.
3*9-
876
Of acids.
folved, which communicates a luminous property to the
oils, fo that when they are fpread upon any furface,
they fhine in the dark. When the oil is completely
faturated with the phofphorus with the affiftance of
heat, and is allowed to cool, part of the phofphorus is
depofited, and cryftallized in tranfparent octahedrons.
When this phofphorated oil is diftilled, phofphorated
hydrogen gas is difengaged.
16. Sulphur eafily combines with fixed oil, with the
affiftance of heat. The folution which was formerly
called ruby offulphur, is of a reddilh colour. W ben
it cools, the fulphur cryftallizes, by which procefs Pel¬
letier obtained fulphur in the form of octahedrons.
When the cooling is too rapid, the fulphur is precipi¬
tated of a yellow colour, in the fliape of needles. If
this fulphurated oil, which has a peculiarly foetid odour,
be diftilled, it affords a great quantity of fulphurated
hydrogen gas *.
17. The acids have a powerful effedt on the fixed
oils. The fulphuric acid, when concentrated, decom-
pofes them. They become brown, thick, and at laft of
a black colour. Water is formed, charcoal is^ precipi¬
tated, and even an acid is formed. Nitric acid in the
cold thickens fixed oils, by communicating part of its
oxygen. In the ftate of nitrous acid it produces a
more violent aftion. 1 here is confiderable effervef-
cence, with the evolution of a great quantity of ni¬
trous gas. If a mixture of nitrous acid and concentrated
fulphuric acid be thrown upon fixed oils, they inftant-
ly inflame, and leave behind a fpongy mafs of char¬
coal. Muriatic acid has little effea on fixed oils, but
the oxymuriatic acid thickens and bleaches them, in the
fame way as tallow or wax.
18. The various purpofes to wdiich fixed oils are ap¬
plied, are too well known to require particular enume¬
ration. They are employed in domeftic economy,
either as articles of food, and for this purpofe are ufed
alone, or in combination with other fubftances j or they
are employed for giving light, by being burnt in lamps.
They are ufed in medicine, either on account of the
properties which peculiar oils poflefs, or on account of
the properties they communicate to other fubftances
with which they are combined. In this ftate the ufe
of oils is well known in the form of unguents, plafters,
and liniments. In the arts, fixed oils are of the moft
extenfive utility. They are employed in the fabrica¬
tion of foaps, for mixing colours in painting, for fome
kinds of varnifti, and for defending fubftances from the
adtion of air and moifture f.
19. The order of the affinities of fixed oils is the
following :
Lime,
Baiytes,
Fixed alkalies,
Magnefia,
Ammonia,
Oxide of mercury,
Other metallic oxides,
Alumina.
Sect. IV- Of Volatile Oils*
879 1. Volatile oils are diftinguiftied from the fixed oils
traders. ^ volatility, fragrance, and acrid tafte. They
are alfo known under the name q{ aromatic oils, from
877
Ufes.
^ Fourcroy
Connaifs
Cbim- vii.
P- 33°*
878
Affinities.
their odour j or effential oils, or Amply effencts, from
being fuppofed to conftitute the ejfence or the ^^ces
of the vegetable matters which furniffi them. ' - v
2. Volatile oils are not limited to particular parts of SBo
plants, but are found to exift in every part of the plant, Na^es-
excepting in the feed, which furniflies the fixed 0^s,pouri^;n
A great number of roots which are generally diftingmfli- all parts of
ed by an aromatic odour, and have more or lefs of an plants but
acrid tafte, afford volatile oils. They are furniftied al- the lobes of
fo by many woods, fuch as thofe of the pine and firthe leeds‘
tribe, and by many of thofe which are natives of
warm climates. The leaves of a great number of
plants belonging to the didynamia clals alfo afford vo¬
latile oil, as well as many of the umbelliferous plants.
It is obtained alfo from many flowers of vegetables, and
alfo from the covering of many fruits, as the ikin ot
oranges and lemons. It is alio obtained from a great
number of feeds j but it .is never found in the cotyle¬
dons or lobes themfelves, but only in the external co¬
vering. The quantity of volatile oil which is obtain¬
ed from vegetables, varies according to the age, the
foil in which they grow', and the ftate of the plant.
Some plants while green furnifh it in greateft abun¬
dance, while others yield moft when they are dry. 8S,
3. There are two proceffes by which volatile oil may prepara^
be obtained. "When it exifts in plants in great abund- tion.
ance, and in veficles in a fluid ftate, it may be fepara-
ted by mechanical means. Thus, by Ample expreflion,
the volatile oils are extracted from many plants, as, for
inftance, from the fruit of the orange and the lemon.
From the outer rind of thefe fruits, w7hen they are
frelh, the volatile oil is obtained in the liquid form j
but in general, the volatile oils of plants are neither fo
abundant, nor do they exift in that ftate of fluidity, by
which they can be procured by fo Ample a procefs.
In moft: cafes they are fubje&ed to the procefs of di-
ftillation ; and for this purpofe they are macerated for
fome hours in water. They are then introduced into
a ftill along with the water; a moderate heat is appli¬
ed and continued till the fluid boil, when a great
quantity of vapour of water, mixed with the volatile
oil, paffes over, and is received in proper veffels. _ The
oil colle&s on the furface of the water, from which it
may be eafily feparated. The water itfelf is of a milky
colour, on account of a fmall quantity of oil fufpended
in it; and even after the water becomes tranfparent by
the particles -of the oil feparating from it, and rifing to
the top, it is ftill loaded with the peculiar odour of the
plant. This was fuppofed to be a feparate principle
of vegetables, to which Boerhaave gave the name of
fpiritus reElor, and which is ftill known by the name
of aroma. This fragrance of the water is owing to
the folution of a certain portion of oil in it- _ In the
diftillation of the volatile oils, different pra&ices are
followed, according to the nature of the plant, and
the proportion of the oil exifting in it. The roots,
wood, bark, fruits, dried plants,after being cut in pieces,
rafped down or bruifed, are macerated for fome hours,
or for fome days, according to the folidity or particu¬
lar ftate of the vegetable matter. Frefh plants are di¬
ftilled with the fmalleft quantity of water,. have no
need of previous maceration, and do not icquire fo high
a temperature. 8S3
4. The volatile oils are particularly diftinguilhed by Fragrance,
their fragrance, which varies in the oils extra&ed from
different
CHEMISTRY.
SSj
Inflam¬
mable fub
itances.
884
Fluidity.
885
Cryltais.
886
Colour.
887
Tafte.
888
A&ion of
light.
* Jour, de
Pbyfeque,
xlvii. p. l6p
8S9
Of heat.
890
«0f air.
891
Of water.
different plants. The confidence of the volatile oils
alt'o varies confiderably. Sometimes they are as iluid
as water, which is the cafe with thofe oils obtained by
expreffion. Some are thick and vifcid, as thofe gene¬
rally are which are extrafted from \V00ds, roots, barks,
and fruits of the warmer regions. Some congeal, or
afiume a granulated folid confiftence at different tem¬
peratures. Of thefe Jaft, fome are always found to be
in the concrete ftate. Several of the volatile oils are
fufceptible of cryftallization, depofiting in the remain¬
ing portion of the oil which continues liquid, tranfpa-
rent polyhedrons, more or lefs of a yellow colour,
which are found to be pure oil. This laft change,
Vauquelin thinks, is owing to an incipient oxidation ;
for it never takes place, unlefs oils have been kept for
fome time.
5. There is great variety of colour among volatile
oils. Some indeed are nearly colourlefs, as the oil of
turpentine 5 but in general they are of different lhades of
colour. Some are yellow, as the oil of lavender ;
fome are of a reddilh yellow or brown, as the oil of
cinnamon or of rhodium j fome are blue, as the oil of
chamomile ; and fome are green, as that of parfley.
But the molt prevailing colour among volatile oils is
yellow or reddifh.
6. Volatile oils have almoft always an acrid, hot, and
even burning tafte. It is obferved that the mo ft acrid
vegetable matters do not yield an oil poffeffed of this
quality. The fpecific gravity of volatile oils is gene¬
rally lefs than that of water. Some volatile oils, how¬
ever, as thofe of faffafras and canella, have a greater
fpecific gravity. The fpecific gravity of oils varies
from 0.8697 to 0.9910, in thofe which are lighter than
water j but thofe which are heavier are from 1.0363
to 1.4049.
7. When volatile oils are expofed to the light, the
colour becomes confiderably deeper; they become
thicker, and increafe in fpecific gravity. In fpeaking
of a fimilar change which takes place in the fixed oils,
this change was afcribed to the abforption of oxygen ;
but, according to the experiments and obfervations of
M. Tingry, this change is effected merely by the ac¬
tion of light ; for in his experiments oxygen gas was
entirely excluded.*
8. When volatile oils are expofed to heat, they evapo-
ate very readily. They are much more combuftible than
the fixed oils j and in burning give out a £reat quanti¬
ty of fmoke, a very bright white flame, and a good
deal of heat. They require a greater proportion of
oxygen than the fixed oils, and yield a greater quan¬
tity of water. This arifes from a greater proportion
of hydrogen, and a fmaller quantity of carbone, which
they contain.
9. When volatile oils are expofed to the open air,
they undergo another change. They affume a deeper
colour, and become vifcid, exhaling at the fame time
a very ftrong odour. The air around is deprived of
its oxygen 5 it combines with the hydrogen of the oil,
and forms water, which is obferved in drops on the
furface. Many of the volatile oils when thus expofed
pafs into the refinous ftate, and are almoft entirely de¬
prived of their odour. This depends on the lofs of
part of their hydrogen, and confequently the increafe
of the proportion of carbone.
10. The volatile oils are in fome degree foluble in
Vox.. V. Part II.
water. When they are agitated with this liquid, they Inflam-
combine with it, and communicate a very ftrong odour, m^'e lub"
and a (lightly acrid tafte. 1 »
11. Pholphorus and fulphur are foluble in volatile 892
oils. With pholphorus the folution is luminous in the Phofphorus
dark, is extremely fetid, and gives' out, by the force ai,‘^ hli"
of heat, phofphorated hydrogen gas. The combina¬
tion with lulphur is known under the name of balfam
of fulphur. This gives out fulphurated hydrogen gas
on the application of heat. g ^
12. The concentrated fulphuric acid produces a Of acids,
brown colour, and increafes the vifcidity of the vola¬
tile oils, and difengages part of their hydrogen with
effervefcence and heat. Part of the oil is decompofed ;
charcoal is depofited, and it contains an acid. Nitrous
acid, when brought into contadl with the volatile oils,
produces inftantaneous deflagration ; conveits them in¬
to water in a great meafure, and carbonic ; and there
remains behind a voluminous mafs of charcoal. Mu¬
riatic acid has fcarcely any aflion ; but the oxymuria-
tic acid renders them colourlefs, concrete in part, or
vifcid, and brings them more nearly to the ftate of
refins. _ • 8
13. Some of thefe oils are employed in medicine. ufes.
They are ufed alfo for the folution of thofe fubflances
which are to be employed as varniftres 5 and many of
them are ufed in perfumery. g(..
14. As many of the volatile oils are produced butTdts ofpu-
in fmall quantity, they are confequently high priced, rity.
There is therefore fome temptation to adulterate them
with fixed oils, with cheaper volatile oils, or wfith
other fubftances, to increafe the quantity. It is there¬
fore of fome importance, to be able to detedl fuch
frauds. When a volatile oil is adulterated with a fix¬
ed oil, there is a very eafy teft to difcover it. Let a
(ingle drop of the oil that is fufpedted fall on clean
paper, and expofe it to a gentle heat. If the oil is
pure, the whole will be evaporated, and no trace re¬
main on the paper 5 but if it has been mixed with a
fixed oil, a greafy fpot remains behind. Volatile oils
are frequently adulterated with oil of turpentine 5 but
this can only be detedlcd by its peculiar odour, which
continues for a longer time than moft of the other vo¬
latile oils. When they are adulterated wdth alcohol,
it is eafily detefted by mixing a little of the oil with
water, w>hich immediately produces a milkinefs, by
the abftradlion of the alcohol from the oil, and its
combination with the water.
15. There is another clafs of oils known under theEmpyreu-
name of empyreumatic oils, which have different pro-maUc °hs*
perties from thofe which have been defcribed. Thefe
oils are acrid and rtimulating, with a ftrongly fetid and
difagreeable odour. It would appear, that thefe proper¬
ties aie owing to a partial decompofition of other oils.
Thefe oils are produced, as the name imports, by the
aftion of fire. They are obtained when oils are forced
to rife in vapour, and pafs over in common dirtillaticn,
with a greater degree of heat than that of boiling wa¬
ter, or by the application of a ftrong heat to fubftan¬
ces from which no oil was jirevioufly extracted. Thefe
empyreumatic oils agree in fome of their properties
with the volatile oils. They combine in final! propor¬
tion with water, and they are foluble in alcohol; and
probably any difference that exifts between them, is
owing to a partial decompofition 5 for when they are
4 A diftilled,
J54 , C H E M
Aikalies. diftllled, the oil is reftored to a ftate of purity, and the
' v carbonaceous matter which had been feparated, re¬
mains behind.
Chap. XII. Of ALKALIES.
Origin of The word alkali is derived from the Arabian name
the name. 0f a piant) which affords the fubftance now diftin-
guiihed by that term. The name of the plant is kali,
to which the Arabic particle al was added, expreffive
of the valuable qualifies of the plant. When other
fubftances were diicovered, poffeffed of iimilar proper¬
ties, the meaning of the term was extended, and ap¬
plied to fuch matters as had feveral common proper¬
ties. Three fubftances are generally ranked under the
head of alkalies. Thefe are potalh, foda, and ammo¬
nia. They are chara&erized by the following proper-
ties.
Characters. I. They have a peculiar tafte, which is difagreeably
cauftic, even when they are diluted with water.
2. They change vegetable blue colours to a green.
3. They have a ftrong attraflioh for water, and
combine with it in all proportions.
4. They have a ftrong affinity for acids.
5. They melt in a moderate heat, but with a ftrong-
8 er heat they are volatilized.
Natural di- The alkalies have been divided into two kinds,
vilion. namely, the fixed and volatile. The two firft, potafti
and foda, are denominated fixed alkalies, becaufe they
require a great degree of heat to diflipate or volatilize
them. Ammonia has been called the volatile alkali,
becaufe a very moderate degree of heat is fufficient to
volatilize it.
Fourcroy has claffed two of the earths, namely, ba¬
rytes and ftrontites, under the head of alkalies. In
fome of their properties, thefe earths, no doubt, are
analogous to the alkalies; but in other properties they
are more clolely allied to the earths. There feems,
therefore, to be no inconvenience or ambiguity in claf-
fing them, as ufual, among earthy fubftances.
It may perhaps be confidered as one of the general
charafters of the alkalies wffiich we have now enume¬
rated, that they have no aftion on oxygen, azotic, or
hydrogen gafes, nor is there any action between the
alkalies and carbone.
Sect. I. Of Potash and its Combinations.
Names. I- This fubftance has been long known in com¬
merce, under many different names, derived from the
fubftances from which it is extrafled, or from the pro-
cefles by wffiich it is prepared. The name of afih or
a^es has been given to this fubftance, becaufe it is
procured from the burnt afhes of vegetables 5 and it
has received the epithet of pot-afhes, becaufe it is pre¬
pared in iron pots. It got the name of vegetable al¬
kali, becaufe it was fuppofed that it only exifted in ve¬
getables. Being prepared from nitre and tartar, it
was called the alkali of nitre or tartar, and the fait of
tartar, a name which it ftill retains in the Ihops. It
has been propofed alfo to diftinguilh it by the name of
kali, the name of the plant from which it was origi-
nally procured.
Prepara- 2. Potafh is generally prepared by burning wood
non. or 0ther vegetable matters, and thus reducing them to
I S T R Y.
afhes. The afhes are then to be waftied repeatedly Fotafh, Sec.
with water, till the liquid comes off perfectly talteiefs. ' v "
If the liquid thus obtained be purified by filtration,
and evaporated to drynefs, a fait is obtained, which is
the potafh. In this ftate it is contaminated with much
extraneous matter j but if it be expoled to a rea heat,
many of the foreign fubftances with which it is mixed,
are diffipated ; it becomes whiter, and from its colour
is then fold under the name of pearl-ap. T his fait is
prepared in great abundance in thofe countnes where
wood abounds, as m North America and the north of
Europe } and hence it is known in commerce under
the name of RuJJian or American pearl ap. . ^Q2
3. Potafti, in this ftate, is confidered as fufficiently in this ftafe
pure for the ordinary purpofes of life to which it is ap- i* impure,
plied ; but it is ftill mixed with much foreign matter,
which renders it unfit for the purpofes of the chemiff.
It has therefore always been confidered as an objedl of
great importance, to obtain it in a ftate of purity.
But even when it is feemingly pure, by being de¬
prived of all extraneous fubftances, it is found to
poffefs very different properties, after being fubjedled
to certain proceffes. In one ftate it is comparative¬
ly mild and ina&ive ; in another, extremely acrid
and corrofive. Various opinions were entertained
of the caufe of this remarkable difference, which ^
it is unneceffary to enumerate. The true caufe was
difeovered and derponftrated by Dr Black in the yearcovery.
1756. This ingenious philofopher, by a few fimple
and fatisfaftory experiments, clearly proved, that the
different effeas of the alkalies, lime, and magnefia,
are owing to their combination wfith a peculiar fub-
jftance, to wTnch he gave the name of fixed air, becaufe
it is fixed in thefe bodies. This fixed air, it has
been already obferved, is now7 known by the name of
carbonic acid. When the alkalies are in combination
with carbonic acid, they are in the mild ftate \ but
when they are deprived of this acid, their effefts being
more powerful and corrofive, they are faid to be in the
cauftic ftate.
When fulphuric acid is poured upon a quantity of
potafh in its ordinary ftate, a violent effervefcence
takes place. This, Dr Black proved, is owing to
the efcape of the carbonic acid in the ftate of gas j
for when the alkali is in its pure or cauitic ftate, no
effervefcence w’hatever takes place. He alio proved,
that the alkalies and lime in their mild ftate, that is,
when combined with carbonic acid, are hea .’icr than
in the cauftic ftate, and that this difference of weight
is exadtly equal to the quantity of carbonic acid
which efcapes. Since,, then, thefe fubftances exhibit
fuch different properties in thefe two ftates, it js necef-
fary to procure them in a ftate of purity, to examine their
properties and effefts. This is not without difficulty,
on account of the ftrong affinity which exifis between
the alkalies and carbonic acid 5 for although they are
perfedtly pure, as foon as they are expoied to the air,
they begin to attraft the carbonic acid and return to
their former mild ftate.. _ > 904
As this, therefore, is an objeft of importance, purifica-
various procefies have been propofed, to procure them tion.
as pure as poflible. Some of thefe proceffes we fhall
now detail. _ . 905
a. The following procefs for the purification of po-Eertholleft
tafh is recommended by Berthollet. It is to be mixed prosefs.
i with
C H E M I
Potafh, See. with double its weight of quicklime, with eight or ten
times the weight of the whole mixture, of pure or
rain water. Boil it for two or three hours in an iron
veflel; then let it remain in a clofe veflel for 48 hours,
taking care to agitate it occafionally. Let it after¬
wards be filtered, and boiled in a filver velTel with a
Itrong heat, till it affume the confiftence of honey.
Pour a quantity of alcohol upon it, equal in weight to
of the alkali which has been employed 5 then put it on
the fire, and let it boil for fome minutes. Pour it after¬
wards into a bottle, and allow it to cool. The matter
in the bottle feparates into three different ftrata : at the
bottom are depofited folid bodies j in the middle there
is an aqueous folution, or carbonate of potalh; and on
the top a liquor of a reddifh brown colour, mixed with
alcohol. Let this be carefully decanted off by means of
a fyphon. This is a folution of pure potalh in alcohol.
Put it into a bafon of lilver, or of tinned copper ; eva¬
porate it rapidly, till a dry, black, and charry cruft
forms on the furface, and the liquor below, which has
an oily appearance, becomes folid by cooling. Let
the cruft be removed, and pour the folution into por¬
celain veffels. When it cools, it becomes folid. It is
then to be broken in pieces, and put into clofe velfels.
This is the potafh in a ftate of purity, not only freed from
foreign matters, but alfo deprived of the carbonic acid.
Lime has a ftronger affinity for carbonic acid than
the potafti. When, therefore, the lime deprived of its
carbonic acid, as it is in the ftate of quicklime, is
brought into contaft in fufficient quantity with the po¬
tafti, it deprives it of the carbonic acid. It is with
this view that the lime is employed in this procefs.
The alcohol has the property of diifolving potafti, but
has no aflion on the other fubftances with which it is
combined. This is the reafon why the alcohol, holding
in folution the pure potafh by its lefs fpecific gravity,
forms the upper ftratum in the bottle. By the eva¬
poration, the laft ftep of the procefs, the alcohol and
water are driven off, and the pure potafh remains be¬
hind in the folid ftate.
- b. A. more economical procefs has been propofed by
JSy^Lowitz. Profeffor Lowitz of Peterfburgh. He boils together
the pot alb and quicklime, as in the former procefs;
filters the liquor, and evaporates, till a thick pellicle
is formed on the furface. It is then fet by to cool,
till eryftals are formed in it, which are cryftals of
extraneous falts, and are to be removed. He then
continues the evaporation, and removes the pellicle as
it forms on the furface during the procefs. When
the fluid ceafes to boil and no more pellicle is formed,
he removes it from the fire, and keeps conftantly ftir-
ring it while it cools. He then diffolves it in double
the quantity of cold water, filters the folution, and
evaporates in a glafs retort, till regular cryftals begin
to be depofited. If the mafs fhould confolidate ever fo
little by cooling, a fmall quantity of water is to be
added, and it muft be heated again, to render it fluid.
When a fufficient quantity of regular cryftals has been
formed, he decants the liquid, which has a brown
colour, and re-diflblves the fait after it is fuffered to
s T R Y. 555
drain, in the fame quantity of water. The decanted Potafh, &c.
liquor is preferved in a well-clofed bottle for feveral ^—1
days, till it fubfide and become clear. He then de¬
cants it, evaporates, and cryftallizes a fecond time,
and repeats this procefs as long as the cryftals afford,
with the leaft poffible quantity of water, folutions that *Nicbolfoni
are perfeffly limpid. Thefe folutions are to be pre-.
ferved in well-clofed bottles, to defend them from the ' **
accefs of ail *. p0y
c. The method of preparing pure potafti by the in- By Kla-
defatigable and accurate Klaproth, is fomewhat differ- [,rot’1,
ent from this. WTe (hall detail it in his own words.
“ As many perfons think that the preparation of a
perfeftly pure cauftic ley is fubjeft to more difficulties
than it really is, I will here briefly ftate my method
of preparing it. I boil equal parts of purified fait of
tartar, (carbonate of potafti, or vegetable alkali pre¬
pared from tartar) and Carrara marble, burnt to lime,
with a fufficient quantity of water, in a polifhed iron
kettle } I ftrain the ley through clean linen, and,
though yet turbid, reduce it by boiling, till it contain
about one half of its w’eight of cauftic alkali ; after
wffiich I pafs it once more through a linen-cloth, and
fet it by in a glafs bottle. After fome days, when
the ley has become clear of itfelf, by Handing, I care¬
fully pour it off from the fediment into another bottle.
To convince myfelf of its purity, I faturate part of it
with muriatic or nitric acid, evaporate it to drynefs,
and re-diffolve it in water. If it be pure, no turbid-
nefs will take place in the folution. The quantity of
cauftic alkali which this ley contains, I afeertain by
evaporating a certain weighed portion of the ley to
drynefs, in an evaporating difti of a known w’eight.
I alfo take care, in the preparation of this cauftic ley,
that the alkali be not entirely deprived of carbonic
acid } becaufe, in that cafe, I can with greater cer¬
tainty, depend on the total abfence of diffolved calcare¬
ous earth. By employing burnt marble, or, in its
Head, burnt oyfter-fhells, I avoid the ufual contamina- * Analyt.
tion of the cauftic ley by aluminous earth ; becaufe F-J[ays->
lime, prepared from the common fpecies of lime-ftone, p' ^
is feldom entirely free from argil” *. '™ci
5. Potalh thus obtained, is a white folid fubftance, properties,
which is fufceptible of cryftallization in long, compref-
fed, quadrangular priftns, terminating in lharp-pointed
pyramids. Thefe cryftals, which are only obtained
from very concentrated folutions, are foft and deliquef-
cent(r). The tafte is extremely acrid ; and it is fo cor-
rofive, that it deftroys the texture of thefts; in, the moment
it touches it. It is from this property that it has derived
the name of cauftic-, and in furgical language it has ob¬
tained the name of potential cautery, becaufe it is em¬
ployed for the purpofe of opening abfeeffes, or for de-
ftroying excrefcences. According to Haffenfratz, the
fpecific gravity of potnfti is 1.7085. It converts ve¬
getable blues into a green colour. ^
6. Light has no abfion on potafti. When it is heat- A&ion of
ed in clofe veffels, it becomes foft and liquid, and is beat,
afterwards converted into a white, opaque, and granu¬
lated mafs, when it cools. If the heat be increafed
4 x\ 2 to
(t) By deliquefcence is meant the melting of fubftances in the water which they attraft from the air. Such
lalts are faid to be deliquefccnt.
4
556
Fotafh, &C.
C H E M I S T R Y.
910
Of water.
91X
Acids.
912
Affinities
913
Ufes.
914
A Ample
fubftance.
to rednefs, it fwclls up, and rifes in vapour. If the
veffel be opened, there arifes a white fmoke, which is
extremely acrid, and condenfes on cold bodies with
which it comes in contaft. But though it is thus
fublimed, it undergoes no other change than affuming
a flight green colour.
7. There is no adtion between potafh and oxygen
or azotic gafes, nor is there any diredt adtion between
potaflr and carbone. Phofphorus and fulphur enter in¬
to combination with potafh, and form peculiar com¬
pounds, the nature of which we fliall confider, after
having detailed the general properties of potaflr.
8. Potafh has a very ftrong affinity for water. Wa¬
ter at the ordinary temperature difiblves double its
weight of potafh. The folution, when the potafh is
pure, is colourlefs and tranfparent, and is nearly of the
conflftence of oil.
9. Potafh combines readily with the acids, and forms
compounds with them, having different properties, ac¬
cording to the nature of the acid which is employed.
Its affinities for the acids are in the following order:
Sulphuric,
N trie,
Muriatic,
Phofphoric,
Phofphorous,
Fluoric,
Oxalic,
Tartaric,
Arfenic,
Succinic,
Citric,
Ladlic,
Benzoic,
Sulphurous,
Acetic,
Sacladlic,
Boracic,
Carbonic,
Pruflic.
10. Potaflr is employed for a great variety of purpo-
fes; it enters into combination with many fubftan-
ces, and forms with them valuable and important com¬
pounds. It is employed in medicine as a ufetul and
powerful remedy } in many arts and manufadlures, as
in bleaching, dyeing, and glafs-making.
11. Potafh is to be coniidered as a Ample fubftance.
No attempts yet made have fucceeded in decompoflng
it. But although not the flighted: proof has been ad¬
duced of its formation or decompoAtion, it is confidered
by fome as a compound fubftance. This opinion is
founded on the analogy of its properties with ammo¬
nia *, the compoAtion of which has been fully demon-
llrated. According to fome, it is compofed of lime
and azote ■, and, according to others, of hydrogen and
lime *, but all thefe are mere conjeftures, which have
probably had their origin in that eagernefs of the hu¬
man mind, which leads it to fancy what it wiftres to be
true.
12. But we ftiall now conAder more particularly
the aftion of the different fubftances which have been
already treated of, on potafh, and the different com¬
binations which it forms with them.
I. A&ion of Phofphorus on Potafh.
I. There is no direft combination betwen
Fotaffi, &c.
915
.. *...— ~ -—   - _ P0^3^1 Phofphora-
and phofphorus but although thefe two bodies have ted nydro-
little tendency to unite, they have a very powerful ef-gen gas.
fed upon each other when they are heated together
with water. It was in this way that Gengembre Arft
obtained the Angular gas, which has been already de-
feribed, when treating of phofphorus, under the name
of phofphorated hydrogen gas. ^
2. If one part of pholphorus and ten parts of a con-procefs for
centrared folution of pure potafh be introduced into obtaining
a fmall retort, and expofed to heat till it boils, phof-
phorated hydrogen gas will pafs over, which may be
received in jars over water: or if the beak of the re¬
tort be kept under the furface of water, the bubbles
of the gas, as they rife to the furface, explode, and
form the beautiful coronet of white fmoke, formerly
mentioned. In making this experiment, the retort
fliould not be larger than to hold the folution, or, it
fhould be Ailed with hydrogen or azotic gafes, in which
the phofphorated hydrogen gas will not inAame and ex¬
plode, with the rifk of breaking the veffel j for the in¬
flammation can only take place when it comes in con-
ta& with the oxygen of the atmofphere. ^
3. In this procefs, the water which holds the potafh Nature 0f
in folution, is decompofed. The oxygen combines with the procefs.
part of the phofphorus, and forms phofphotic acid, while
another part of the phofphorus unites with the hydro¬
gen, and paffes over in the form of phofphorated hy¬
drogen gas. Thus, without any perceptible aftion be¬
tween the phofphorus and the potafh, the decompofi-
tion of the water is aided by means of the potafh, in
confequence of its attra&ion tor the phofphorus, com¬
bined with the oxygen in the ftate of phofphoric acid.
For it is found, that a quantity of phofphate of potafh
is formed, correfponding to that of the phofphomted
hydrogen gas which is obtained. This decompoAtion
is alfo affifted by the affinity of the phofphorus for the
oxygen and hydrogen of the water. The whole of the
phofphorated hydrogen gas which is formed, be ng dif-
engaged, Aiews that no combination takes place be¬
tween it and the potafh *. * Fourcroy
Connaifs.
II. A&ion of Sulphur on Potafh. chim. tom.
I. Sulphur and potaAi very readily combine toge-n-P-202’
ther. If one part of potaAr and three of fulphur be
triturated together in a glafs or porcelain mortar, the
mixture becomes hot, the fulphur lofes its yellow co¬
lour, and acquires a greenifh tinge. There is difen-
gaged a fetid fmell of garlic ; the mixture attra&s
moifture from the air, becomes foft, and is almoft en¬
tirely foluble in water. 5Ig
If two parts of potafh and one of fulphur be well suip}juret
mixed together, and heated in a crucible, the mixture of potato,
fufes ; and by this procefs is obtdmeA fulphuret of pot-
ajh in the dry ftate. This was formerly called hepar
fulphur is, or liver offulphur, from its refemblance to
the liver of animals. The lame fubftance may be ob¬
tained by treating fulphur with the potafh of com¬
merce, with this precaution, not to apply too ftrong
a heat, to occaflon a fublimation of the fulphur, and
the too rapid evolution of the carbonic acid from the
potafh. When the fufion is completed, it is poured
out
C H E M
potato, fee.out on a marble flab; it is covered up from tbe air,
  v ' allowed to cool, and broken into fmall pieces, to be
inflantly put up in well-clofed glafs veffels.
Properties. 2. The folid fulphuret of potalh thus prepared, is of
a {himntT brown colour like that of the liver of ani¬
mals, from which it derived its former name. Expo-
fed to the air it becomes green, then paffes to gray,
and even to white. It is denfe, fmooth, and has a
vitreous fra&ure. It has no other fmell than that of
heated or fublimed fulphur ; is acrid, cauftic, and bit¬
ter to the tafte, and leaves a brown fpot on the Ikin.
With a ftrong heat, in a porcelain retort, the fulphur
is fublimed, and the potafh remains in a Hate of puri¬
ty at the bottom of the veffel. The fulphuret of pot¬
afh converts vegetable blue colours to green, and af-
2Q terwards deflroys them.
Hydro-ful- 3. But the fulphuret of potafh pofleffes thefe proper-
phuret. ties, only while it is recently prepared, and very pure.
When expofed to the air, it is readily decompofed, and
more fo, as the air is loaded with moifture. It ab-
forbs water with avidity, acquires a green colour, and •
exhales the fetid odour of fulphurated hydrogen gas.
This change is owing to the decompofition of the wa¬
ter which has been abforbed. Part of the fulphur
combines with the hydrogen, and forms fulphurated
hydrogen gas, which combines with the fulphuret, and
forms hydrogenated fulphuret of potafh. ^ *
911 , 4. This may alfo be formed by palling the fulphu-
by another rated hydrogen gas into a folution of potafh. The gas
procefs. is abforbed and condenfed, till the potafti is fully fatu-
rated. To this fubftance Berthollet, who particularly
invefligated the nature of thefe compounds, gave the
name of hydro-fulphuret of potafi.
Properties. This compound cryftallizes, and is more permanent
than the fulphuret. The cryftals are tranfparent
and colourlefs, while thofe of the fulphuret are brown
and opaque. The cryftals are large and in the form
of four-fided prifms, terminating in four-fided pyra¬
mids. It is decompofed by heat, and by the a&ion of
the acids. Sulphurated hydrogen gas is difengaged,
but there is no depofition of fulphur. The oxymuria-
tic acid decomfiofes the fulphurated hydrogen, and
then fulphur is precipitated. The pure hydro-fulphu-
ret has no fmell, when it has no addition of fulphur
bevond the faturation of the hydrogen. The alkali
feems to have a ftronger affinity for the fulphurated
hydrogen than for the fulphur, fo that when it is fatu-
ratf'd with the firft, that is, in the ftate of hydro-iul-
phuret of potafh, which is in the form of cryftals, and
without fmell or inodorous, it combines with no
more fulphur; but when fulphurated hydrogen gas is
made to pals into a folution of the fulphuret of potafh
already hydrogenated by its folution in water to a cer-
* Fourcroy tain degree of faturation, the fulphurated hydrogen
Connaif. afts in the manner of acids, precipitates the fulphur
Cbbn. *om. Jjke them, renders the liquid colourlefs, and leaves
ii. p ao(S. kghind nothing but the hydro-fulphuret of potafh *.
Hydrogen S‘ Sulphur combines with the latter compound, and
I S T R Y. 557
forms a new compound, which may be obtained by Potato, Sco
pouring a liquid hydrofulphuret upon fulphur. I he 'r~’
fulphur is diffolved without the aflirtance of heat ; the
liquid affumes a darker colour, and then it is convert¬
ed into the hydrogenated fulphuret. Hydrogenated ful¬
phuret of potafh is prepared by boiling together a mix¬
ture of pure potafh and fulphur in water. This folu¬
tion is of a deep greenifh yellow colour, has a very
acrid bitter tafte, and a powerful aftion on many fub-
ftances. It readily abforbs oxygen when expofed to
the air. When it is kept in clofe veffels, fulphur is
depofited ; the liquid becomes tranfparent, and the
fmell is diffipated. Thus, there are three different
compounds of fulphur with potafh ; namely, fulphuret
of potafh, hydrolulphuret of potafh, and hydrogenated
fulphuret, which are all diftinguifhed by peculiar pro¬
perties.
III. Compounds of Potafh with Acids, or Neutral
Salts.
I. Sulphate of Potafh (u).
024
1. This fait, which was one of the moft early known, igames.
is a compound of fulphuric acid and potafh. It has
been diftinguifhed by a*great variety of names, asyh/ de
duobus, fal polychrcfus, or fait of many virtues, arca¬
num duphcatum, and more lately vitmolated tartar, till
in the new nomenclature it received the name oiful-
phate of potafh. n- ■ v 1, P2S
2. It is prepared by different procenes, either by prepara,
directly combining the fulphuric acid with the pot- tion.
afh, and evaporating and cryftallizing it; or lay de-
compofing other falts which have potafh for theii bafe,
by means of the fulphuric acid, which-having a ftrong¬
er affinity for the potafh, combines with it and forms
the new compound. 926
3. The fulphate of potafh cryftallizes in hexaedralProperties-
prifms, terminated by fix-fided pyramids ; but this-
form is fufceptible of feveral varieties. It has a difa-
greeable bitter tafte, it is not very hard, and may be
eafily reduced to powder. The fpecific gravity is
2.4073. At the temperature of 6o°, it is fbluble in 16
times its weight of water ; boiling water diffolves about
one-fifth part ; on cooling it cryftallizes in a confuted
mafs ; and it is only by flow fpontaneous evaporation
that regular cryftals can be obtained. ^ _
4. It fuffers no change by the a£lion of the air. A(c^on 0f
When placed upon burning coals, it decrepitates, and heat,
lofes its water of cryftallization. At a greater heat
it melts, and is converted into a kind of enamel as it
cools.
5. When this fait is expofed to a red heat, along^
with hydrogen gas or carbone, it is decompofed, and
converted into a hydrogenated or carbonated fulphu¬
ret of potafh.
6. The fulphuric acid, with the affiftance of heat,
combines with the fait, and forms another with excefs of
acid. It undergoes a partial decompofition by the ac¬
tion
ated ful-
phuret.
(u) The compounds of acids with any bafe are known by this name in the prefent chemical nomenclature ,
and when the acfd has its greateft proportion of oxygen, as in this cafe the fulphuric acid, the ^me of the-
compound terminates in the fyliable ate, as fulphate of potafh, nitrate of potaih ; but when the acid has its fma
proportion of oxygen, the name of the compound terminates in Ue j as fulphite of potafh, nitrite cl pota .
558 CHE M
Potafli, See. tion of nitric acid. The nitric acid combines with
l“"’—nearly of the potafli, which is owing to the action of
double affinity. The nitric acid combines with one
part of the potafli, while the fulphuric acid unites with
the fulphate of potafh, and forms a fait wdth excefs of
acid. A flmilar decompofltion takes place by means of
the muriatic acid.
7. The component parts of fulpbate of potafh are,
according to
Bergman, Kirwan,
Acid 40 - 45.2
Potafli 52 - 54.8
Water 8 - 00.0
928
Compofl-
tion.
ICO
100
929
Names.
93°.
Properties.
93i
Action of
water.
932
Of heat.
933
Hydrogen.
Acidulous fulphate of potafj, or fuper fulphate of pot¬
afh.— 1. This fait was formerly called vitriolated tar¬
tar with excefs of acid. It is prepared by heating to¬
gether, in a retort, three parts of the fulphate of pot¬
afh, with one part of its weight of concentrated fulphu¬
ric acid.
2. Itcryftallizes in long, flexible, fliining cryftals, and
fometimes it exhibits the form of fix-fided prifms. It
has a fharp, acrid, and hot tafle. It reddens vegetable
blues. Expofed to the air it becomes a little more
opaque, but without any other change. It is more fo-
luble in water than the fulphate of potafli, requiring
only 2 parts of water at 6o°, and diflblves in lefs than
its owm weight of boiling water. It melts very readily,
and has the appearance of a thick oil. When it cools, it
becomes a white, opaque mafs, exhibiting on its furface
Ihining filky cryftals. When expofed to a great heat,
the excefs of acid is driven off, and it is converted into
the fulphate of potafh.
3. It is readily decompofed by the aftion of hy¬
drogen and of red-hot charcoal, which deprive it of
a great portion of the fulphur \ and by fulphur itfelf,
which carries off the excefs of fulphuric acid in the
form of fulphurous acid.
4. The firft of thefe frits, the fulphate of potafli, is
employed in medicine as a purgative ; the laft has been
applied to no ufe whatever.
2. Sulphite of Potafh.
Names and t. This fait w^as long known under the name of the
fulphurous fait of Stahl. It is a compound of the ful¬
phurous acid and potrfti. Its nature and properties
have been particularly inveftigated by Berthollet,
Fourcroy, and Vauquelin. It may be formed by paf-
fing, a current of fulphurous acid gas into a folution of
carbonate of potafh in three times its weight of diftilled
W'ater, till the effervefcence ceafes. The liquor be¬
comes tranfparent and hot, and as it cools, the fulphite
of potafh is depofited in cryftals.
Properties. 2. This fait is in the form of long, fmall needles,
diverging from a center, or in rhomboidal plates, or in
decahedrons formed by two tetrahedral pyramids,
1 s t R y.
united and truncated very near the bafe. The cryftals Fotafh, Sto*
are white and tranfparent, but fometimes of a flight v—
yellow colour. The tafte is acrid and fulphureous.
The fpeciftc gravity is 1.586. The fulphite of potafh, Adtion of
expoied to the air, very readily efllorefces (u); becomes the air.
white and opaque, and is converted into fulphate of
potaih. This is owing to the fulphurous acid abftra£f>
ing oxygen from the air, and becoming fulphuric acid.
It is very foluble in water, at the temperature of the
atmofphere, and much more fo in boiling wrater. When
this folution is expofed to the air, it is foon covered
writh a thick pellicle, which falls to the bottom, and is
afterwards replaced by another. This is the fulphate
of potafh, which is formed in contaft: with the air.
The oxymuriatic acid gas combined with this folution,
forms almoft immediately fhining cryftals of the fulphate
of potafh. ... P37
3. Charcoal heated with this fait in a retort, yields Of char,
fulphurated hydrogen gas, and carbonic acid j and there coab
remains in the retort, a hydrogenated fulphuret of pot¬
afh.
3. Nitrate of Potafh.
** p ^ 8
1. This fait is compofed of nitric acid and potafh, Conilituert
and is well known under the names of and parts and
nitre. It has alfo been denominated fait of nitre, nitren'mt%’
of potafh, or nitratedpotafo. It is one of the moft im¬
portant of the falts, not only on account of the attention
which it has excited, in tracing its formation, and
ftudying its nature and compofition, but alfo on ac¬
count of its numerous and valuable applications in do-
meftic economy and in the arts.
2. The nitrate of potafh exifts ready formed in Found in
many plants, as in tobacco, borage, buglofs, pellitory. many
It has been obferved cryftallized in needles in their iA'11313,
dried ftalks. According to feme, it has been abforb-
ed by the vegetable from the foil in which it grows,
while others fuppofe that it is formed within the plant,
from the elementary principles.
Nitre exifts in great abundance on the furface of the
earth in different parts of the world, efpecially in the
warmer regions, as in India, Egypt, find South Ame¬
rica. But the produdlion of nitre is net limited to
thefe countries. It is produced artificially in Germany prepare(j
and France, by means of what are called nitre /Wr. artificially.
Thefe are formed by colledling together the refufe of
animal and vegetable matters, in which the putrefac¬
tive procefs is going on. They are mixed with earthy
fubftances, but chiefly with calcareous earth, fuch as
the rubbilh from buildings, or colledlions of the foil in
which lime abounds. All that is neceflary to favour
the formation of the nitre, is to moiften occaficnally
with water the mixture of the animal, vegetable, and
earthy matters j to expofe it to a moderate tempera¬
ture, and to defend it from rains, which would carry
off the fait as it is formed. This artificial produdlion
of nitre was greatly improved and extended by the
French during the late war, when they were preclud¬
ed
(u) A fait is faid to efflorefee, when deprived of its water of cryftallization in the ordinary temperature of the
atmolphere. A powdery cruft is firft formed on the furface •, and as the procefs goes on, the whole falls down
into powder. The term ejforefcence is oppofed to ddiquefcence, by which the deliquefeent fubftance attracts
moifture from the air.
941
Purifica-
C H E M
PotaiTi, 5tc, ed from t’ne ufaal fupply of this fait from India. It
  is now produced, it is faid, in great abundance in
France.
The nature of the procefs, and the change which
takes place in this artificial prcdudtion of nitre, will
be underftood by confidering its component parts. The
conftituent parts of the nitric acid are azote and oxy¬
gen. The oxygen is furnifhed by the air; and unlels
there is a fupply of air, no change takes place. A
great quantity of azotic gas is given out by animal
matters during the putrefadive procefs. But although
thefe fubftances, when brought into contad with each
other, do not combine to form nitric acid, it has been
found by experiment, that azote, in its nafcent date, or
in the moment of evolution, enters into union with oxy¬
gen, and forms nitric acid, wmile the nitric acid thus
formed combines with the potafir which is furnilhed by
the foil, or the vegetable matters.
3. After the nitre is formed, it is mixed with water,
which is evaporated, and a fait is obtained of a brown
colour, which is called crude nitre. This is a mixture
of feveral falts, and from thefe the pure nitre is fepa-
rated by other procefies. When it is fufficiently
purified, it is obtained in cryflals of fix-fided prifms,
terminating in fix-fided pyramids. The primitive
form of its cryftals is a redangular odahedron, in which
two faces of a pyramid are inclined to the other pyra¬
mid at an angle of 120°, and the two others at an
angle of 111°. The form of the integrant molecule
is the tetrahedron ; but there are confiderable varieties
in the cryftals of this fait, according as it is llowly or
more rapidly evaporated.
4. This fait is diftinguifhed by a cool, ftrarp, and bit-
teriftr tafte. It is very brittle. When nitre in large
cryftals is reduced to powder, it is found to be a little
humid ; but that which is in the form of a white, opaque,
irregular mafs, yields a dry powder, on which account
it is generally preferred for many purpofes, particular¬
ly in the manufadure of gunpowder. The fpecific
gravity of nitre is 1.9369. It is not altered by ex-
pofure to the air. At the temperature of ~6o° it dif-
folves in feven times its weight of water, and during
the folution, a great degree of cold is produced.
Boiling water diffolves twice its weight of this fait.
5. When the nitrate of potafti is expofed to heat, it
fufes before it'becomes red, and is converted into a
liquid of an oily confiltence. It lofes but very little of
its water of cryftallization, and if it be allowed to cool,
it congeals into an opaque mafs with a vitreous frac¬
ture, which is known by the name of mineral cryjial.
While it is melted, it undergoes no change ; but when
the temperature necefihry for limple fufion isincreafed,
it gives out oxygen gas to the amount of about \ of
its weight. Towards the end of the procefs, azotic
gas is evolved, and ths potafti remains behind pure, fo
that the fait has been completely decompofed. But to
effedt this decompofition, a very ftrong heat is necef-
fary. Wrhen only part of the gas is extradled, the ni¬
trate of potafti is converted into the nitrite.
6. When nitre is mixed with charcoal in the pro¬
portion of three parts of the former to one ot the lat¬
ter, a violent inflammation takes place, either by ex-
pofing the mixture to a red heat, or by bringing
it into contaft with a burning body.- Or the mixture
may be projected into a red-hot crucible, whep a de¬
94^.
Properties.
943
Action of
heat.
944
Of char¬
coal.
I S T R Y. 559
flagration or detonation takes place, and when the re-Potaili, &c.
fiduum in the crucible is examined, it is found to be pot- ^ Ta *
alh partly united with carbonic acid, or the carbonate of
potafti. This was formerly called nitre fixed by charcoal,
or an extemporaneous alkali ofi nitre. The deflagration
in this cafe is owing to the combuftible matter, the
charcoal, coming in contaft with the oxygen which is
evolved by the nitre, expofed to a high temperature. In
another procefs, this experiment was performed in clofe
veflels, to colledl the elaftic fluids which are difenga-
ged ; and befides the carbonic acid gas which is formed
by the union of the carbone and oxygen, and the azo¬
tic gas diiengaged by the decompofition of the nitre, a
fmall quantity of water was found in the veflels. To
this produdl the alchemifts gave the name of ciyfius, and
aferibed to it very wonderful properties in the prepara¬
tion of the philbfopher’s ftone.
7. A violent deflagration alfo takes place when of phof-
phofphorus and nitre are treated in the fame way. Butplwnis.
this experiment fhould be performed with very fmall
quantities, and with great caution. A mixture of nitre
and phofphorus ftruck fmartly with a hammer, produces
a very violent detonation. 945
8. When fulphur is combined with three times its Of fulphur-
weight of nitre, it burns with great rapidity. This
preparation was formerly made by detonating the two
fubftances in a red-hot crucible. The produft is ful-
phate of potafh, known by the name of fial polychrefi
of GlaJ'er. The fulphur combines with the oxygen
of the nitric acid, and forms fulphuric acid, which en¬
ters into combination with the potafti. 947
9. But one of the moft important combinations ofOunpow-
nitre is with charcoal and fulphur, in the formation ofder-
gunpowder. This fubftance was firft known in Europe
in the 14th century. It is faid that it was known to
the Chinefe much earlier. The proportions of the ma¬
terials which enter into the compofition of gunpowder
Nitre
Charcoal
Sulphur
76
15
9
The materials ar& firft reduced to a fine powder fe- prep|raa
parately. They are then carefully mixed together, tion.
and formed into a pafte with a little water. When
the pafte has dried a little, it is forced through a fieve,
by which means it is reduced to grains of fuch a fize as
may be wanted. The powder is then dried in the air, or
in the fun ; and, after being dried, it is put into bar¬
rels which turn round by means of machinery, and thus
by the friftion of the grains of powder againft the lides
of the barrel and againft: each other, it is polifhed.
Thisis called glaring the powder. 949
10. The theory of the combuftion, and terrible ef-Nature of
fefts of gunpowder is thus explained. The fulphurlts a<^ons
and the charcoal burn with great rapidity by the ad¬
dition of the nitre with which they are intimately mix¬
ed. During the combuftion carbonic acid gas, azotic
gas, fulphurous acid gas, and according to fome, ful-
phurated hydrogen gas, are formed. Water and am¬
monia alfo are faid to be produced *. But according * Fourcroy
to Mr Cruickftiank, the quantity of water formed is
not perceptible. The fubftances which remain after 1
the deflagration are; carbonate of potafti, fulphate and
lulphuret
560
Potato, 8tc.
95?
Fulmina¬
ting pow¬
der.
CHEMISTRY.
95'
Powder of
fufion.
952
Fluxes.
953
Compoii-
tion.
954
tlfes.
fulphuret of potaftt, and fome charcoal. It is obvious,
that the irrefiftible effe£ls,of gunpowder are owing to
the fudden evolution and expanfive force of the elailic
fluids which are formed and difengaged.
11. Another combination of nitre produces effects flui
more terrible. When three parts of nitre, two parts of
potafli, and one of fulphur, are previoufly well dried and
mixed together by trituration, they form a compound
which is known by the name oifulminating powder. A
few grains of this mixture expofed to heat in an iron ladle
firft melt, affuming a darker colour; ana when the w hole
is in fulion, there is a violent explofion._ The heat
fbould be applied flowly and gradually, till it is com¬
pletely fluid, and then by bringing it nearer the heat,
the full effedt of the explofion is obtained. This com-
buftion and explofion are alfo owing to the inftantane-
ous evolution of elaftic fluids. The potafti unites with
the fulphur, and forms a fulphuret,. which, with the al-
fiftance of the nitre, is converted into fulphurated hy¬
drogen At a certain temperature the fulphurated
hydrogen gas is difengaged, along with the oxygen gas
of the nitre, and fuddenly taking fire, ftrikes the an
by the explofion which accompanies the evolution of
the gafes. When the mixture is made with equal parts
of nitre and folid fulphuret of potafti, the detonation is
more rapid, but the explofion is lefs violent. With
three parts of nitre, one of fulphur, and one of fawduk,
well mixed together, what is called, powder offujion
is formed. If a little of this powder is put into a wal¬
nut {hell, with a thin plate of copper rolled up, and the
mixture fet fire to, it detonates rapidly, and reduces
the metal to a fulphuret, without any injury to the
fhell. „ . ,
12. A mixture of equal parts of nitre, and taitar
detonated in a crucible, gives a produft which is much
employed in metallurgy. This compound, called white
flux, is a mixture of pure potaflr with the carbonate.
When one part of nitre and two of tartar are treated in
the fame manner, the prbduft obtained is a mixture of
potafli and charcoal. From its black colour,, it is
known under the name of black flux. This alfo is em¬
ployed for a fimilar purpofe.
I 3.Nitrate of potafli, according to Bergman, is com*
pofed of
31 acid,
61 potafli,
8 water.
100
According to Kirwan, it is compofed ot
44 acid,
51.8 potafli,
4.2 water.
100.0
14. Nitre is not only employed for the purpofes al¬
ready mentioned, but it is ufed ip medicine as a cool¬
ing remedy m feveriflr diforders, and as a diuretic m
urinary affeftions. It is employed alfo in many arts,
as in dyeing, and in domeftic economy, for the pre-
fervation of animal matters, which are to be ufed as
food. To thefe fubftances it imparts a red colour.
From nitre, nitric acid is obtained, by decompofing it
by means of fulphuric acid. Nitre is alfo employed
to burn along with fulphur m the formation of fulphu- Potato, See.
lie acid.
4. Nitrite of Potafli.
'Phis fait cannot be formed by diie£t combina¬
tion of the nitrous acid with potafli} but it a quantity
of nitre be expoied for fome time in a crucible or re¬
tort, to a ftrong heat, it becomes deliquefeent and
acrid. It changes the blue colours of vegetables into
green, attrafts moifture from the air, detonates feebly
with combuftible fubfiances, and gives red thick vapours
by the aftion of fulphuric, nitric, muriatic, phofpho-
ric, and fluoric acids. This is the nitrite, of potafli,
which is decompofed by thefe acids, and gives out the.
red fumes of nitrous acid. Little more is known of
the nature of this fait, with regard to its form, folubi-
lity, affinities, or proportion ot its conftituent parts.
Muriate of Potafli.
955
1. This fait was formerly known by the nameNames.
fage fait of Sylvius. It was afterwards called digeftive
fait, regenerated fea fait, and by Bergman, fahted ve¬
getable alkali. ' . . - .
2. It is prepared by the direfl combination ot muri¬
atic acid and potafti. The folution is evaporated till a
pellicle appears, when it is fet by to cryftallize.
3. The cryftals are in the form of regular cubes, otpr0pel.^eS(,
reftangular parallelepipeds. It has a difagreeable bit¬
ter tafte, and by this is eafily diftinguiflied fiom mu¬
riate of foda or common fait. The fpecific gravity of
this fait is 1.836. When the air is moiff, it. deli-
quefees ; but when the air is dry, it parts with its
moifture. Three parts of cold water are fufficient for
its folution. Boiling water diffolves a little more,
but regular cryrtals cannot be obtained by cooling.
The folution muft be left to flow, fpontaneous evapora-
tion. , 957
4. When the muriate of potafli is expofed to heat, Adhon of
it decrepitates, lofes its cryftalline form, and falls into ieat-
powder by the feparation of .08 parts of its weight of
water. When it acquires a red heat, it melts ; if the
temperature be elevated, it is fublimed in the form of
wdiite vapour, unchanged. After complete fufion, if
it is allowed to cool fuddenly, it becomes folid, and
divides on the furface, into many fmall plates of a
fquare form.
r This fait is decompofed by. means of the iulphu-
ric and nitric acids. The firft difengages the muriatic
acid with effervefcence in the gafeous form. By the
action of the nitric acid the muriatic acid is con¬
verted into the oxymuriatic by combining with, the
oxygen of the nitric acid. With one part of nitric
acid and two parts of muriate of potafli, a compound
of the two acids is formed, which was formeily em¬
ployed in the folution of gold. This is a nitro-muna-
tic acid, ox aqua regia. T.T,r958
6. This fait is no longer employed in medicine. ItUfes.
is recommended to be ufed for the decompofition of
nitrate of lime in the mother waters ot nitre, to obtain
the nitrate of potafli, and alfo for procuring the cry-
ftallization of alum.
6. Hyperoxymuriate of Potafli. ^ ^
I This lingular fait was the firft known of all theDitcovery
combinations with the acid in this ftate. Four.croy and hiitory.
mentions,
CHEMISTRY.
Potafh, &c,
p5o
Propenies.
961
Aftion of
lie at.
$6z
Of char¬
coal.
963
Of fulphur.
954
Of phof-
phorus.
mentions, that Dr Higgins prepared this fait, which he
calls nitre, by pafling the oxymuriatic acid gas into a
folution of potafh ; but he feems to have paid no farther
attention to it, except obferving, that it detonated on
red-hot coals (x). It was firft formed, and its nature
and properties were firft inveftigated, by Berthollet.
And fince its difcovery, it has been particularly exa¬
mined by Lavoifier, Dolfuz, Vanmons, Fourcroy,
and Vauquelin, on the continent, and in England by
Hoyle and Chenevix. The method of preparing this
fait has been already defcribed (at N° 556, p. 520.)
in treating of hyperoxymuriatic acid. After the fait
has been removed from the folution in which it cry-
ftallized, it may be purified by diffolving it in boiling
water. The folution may be filtered, and allowed to
cool, when the cryftals are depofited.
2. The cryftals of this fait are moft commonly in
the form of fquare plates or of parallelepipeds, of a
{hining filvery white colour. The primitive form of
the cryftals is an obtufe, rhomboidal prifm 5 they are
very tranfparent and brittle } the tafte is cool, pun¬
gent, and difagreeable, very different from that of ni¬
trate of potato. When it is rubbed fmartly, it phof-
phorefces, and gives out a great quantity of fparks or
luminous traces.
3. It becomes yellow after long expofure to the
air, but is otherwife not changed. It is foluble in
about 20 parts of water at the ordinary temperature of
the atmofphere j but boiling water diffolves about one-
third of its weight, fo that the whole is nearly cryftal-
lized by cooling.
4. When this fait is expofed to heat, although it
contains a confiderable proportion of water of cryftal-
lization, it fufes quietly j and when the heat is increa-
fed, it gives out a quantity of oxygen gas nearly equal
to one-third of its weight. This is the pureft oxygen
gas that can be obtained.
5. But the moft extraordinary effefts of this fait
are thofe produced by its aftion on combuftible fub-
ftances.
a. If a fmall quantity of charcoal reduced to pow¬
der and this fait be rubbed together in a mortar,
there is a flight explofion, and the charcoal is in¬
flamed.
i>. Three parts of the fait with one of fulphur, rub¬
bed together in a mortar, produce a violent detonation.
Or, if the fame mixture is ftruck with a hammer on
an anvil, there is an explofion like the report of a pi-
ftol (y).
c. The fame effe£! is produced by employing phof-
phorus, and treating it in the fame way with this fait.
One or grains of the fait toould firft be reduced
to powder, and brought together to one place in the
bottom of the mortar, and then introducing the phof-
phorus, and rubbing it ftrongly on the fait, a vio-
Vol. V. Part II.
561
lent explofion will inftantly take place. A fimilar de- Potafli, &o
tonation may be produced with the fame fubftances,'"v
by percuflion.
Three parts of the fait, one-half part of fulphur,
and one-half of charcoal, give more rapid and ftrong-
er detonations, with the evolution of a very bright
flame. Detonations are alfo produced, by treating this
fait with fugar, gums, oils, and feme metallic fub¬
ftances. ptf-
6. When concentrated fulphuric acid is poured upon Of acid?-
this fait, there is a confiderable detonation; it is thrown
about to a great diftance, fometimes with a red flame j
and there is exhaled a brown vapour, accompanied
with a ftrong odour of oxymuriatic acid. Even when a
lighted taper is brought into contadl with the gas w hich
is difengaged, it explodes more violently than when the
acid firft came in contact with the fait. In fome
cafes, the explofion was fo fudden and fo violent, that
it broke the veffels in which the mixture was made.
This happened to Mr Hoyle of Manchefter, and af¬
terwards to Mr Chenevix j fo that experiments with
fulphuric acid and this fait, toould be conduced
with fmall quantities, and wdth great caution. If con¬
centrated fulphuric acid be poured on any of the mix¬
tures of this fait with fulphur, charcoal, the metals, or
with fugar, there is an inftantaneous inflammation, the
moft brilliant that can be conceived. There is no de¬
tonation, but the combuftion is extremely rapid, and
the odour of oxymuriatic acid is perceptible. Con¬
centrated nitric acid poured upon this fait, caufes it to
crackle and effervefce, but without explofion, and
without flame j oxymuriatic acid gas is difengaged.
With the muriatic acid this fait produces effervef-
cence, with the evolution of a confiderable quantity
of gas, fimilar in colour and fmell to oxymuriatic
acid gas; but in fome of its properties confiderably
different. This gas is more rapidly abforbed by wa¬
ter. If a fmall jar or bottle be filled with this gas,
and a flip of paper moiftened with ether be introduced
into it, and the mouth of the jar be flightly covered
to prevent the contaft of air, an explofion takes place,
with a depofition of charcoal. A fimilar experiment
may be made, by moiftening a feather wdth oil of turr
pentine, and introducing it into the jar filled with this
gas. It inftantly takes fire with a red flame, and a
great quantity of black fmoke.
7. According to the analyfis of this fait, as given Compoil-
by Fourcroy, it confifts of
tion.
Muriate of potato,
Oxygen,
67
33
£ Fourcroy
But according to the experiments of Mr Chenevix, Cctmaifs.
its conftituent parts are, Cbim. m.
4 B Acid,’^'
(x) “ The acid elaftic fluid (fays Dr Higgins), which iffues when two pounds of manganefe are mixed and
diftilled with two or three of ordinary fpirit of fea fait (muriatic acid), may all, except a fmall portion of phlo-
giftic air, be condenfed in a folution of fixed vegetable alkali 5 and the folution, thus impregnated, yields a con¬
fiderable quantity of nitre, which cryftallizes in the ordinary form, and detonates on red-hot coals. The folu¬
tion at the fame time yields regenerated fea-falt (muriate of potafli).” Higgins, Exper. p. 181.
(y) In experiments with this fait, the quantity employed ftiould never exceed one or two grains, at Jeaft
by thofe who have not been previoufly acquainted with its terrible effeds.
562
Potaih, &c.
f Phil.
'Tranf.
1802.
C H E M
Acid, 58.3
Potafli, 39-2
Water, 2.5
100.0 f.
967 8. I'his fait has been employed in bleaching j bat
other fubftances, particularly lime, have been fubflitut-
ed for the potaih j fo that at prefent it is more rarely
ufed. It \vas propofed by M. Berthollet, when he
firil; obferved its effects, to employ it as a fubllitute
for nitre in the manufacture of gunpowder •, and when
it was tried in the way of experiment, it feemed to be
more powerful than the ufual component parts of pow¬
der } but when it was attempted to be made in the
large way, at Effone in the year 1788, a dreadful ac¬
cident, rvhich happened by the fpontaneous explofion
of the mixture, in the death of M. le 1 ors, and Ma-
demoifelle Chevraud, prevented its effefts from being
fairly proved. The danger which attends the tritura¬
tion of the proper materials wdth this fait, has preclud¬
ed any future attempt.
7. Fluate of Potaih.
Little8 This fait has only been examined by Scheele and
known. Bergman. It is the combination of fluoric acid
with potaih. When the acid is faturated, there
is formed a gelatinous mafs, which does not cry-
ftallize, and which has a llightly acrid faline talte.
When it is evaporated to drynefs, and expoled to the
air, it attraCls moiilure. If it be ftrongly heated in a
crucible, it fufes without effervefcence. It then be¬
comes cauftic, is very foluble in water, and is decom-
pofed by the fulphuric and nitric acids.
8. Borate of Potaih.
This is a compound of the boracic acid and potaih 5
but very little is known of its nature and properties.
It is prepared by decompofing nitre by means of the
boracic acid with the afliftance of heat. The heat
drives off the nitric acid, and there remains behind a
white, half-fufed porous mats, which is foluble in wa¬
ter and yields by evaporation and cooling, fmall cry-
ffals. The fame fait may be formed by direft com¬
bination of the boracic acid and potaih. This fait
feems to be analogous in many of its properties to borax.
9. Phofphate of Potalh.
This combination of phofphoric acid with potafh
was announced and defcribed by Lavoilier in the year
1774. Its properties have been more carefully invef-
tigated by Vauquelin j but from the inveffigation of
other chemifts it appears, that there are two falts form¬
ed from the fame acid and bale •, the one in which
they are neutralized, and the other in wThich there is
an excefs of acid.
a. Super phofphate of Potafh, is formed by the direft
combination of phofphoric acid and potaih. This fait
6 does not cryftallize, but exifts in a gelatinous form,
Properties, and has a fweetilh faline tafte. Its fpecrfic gravity,
when dry, is 2.8516. It is very foluble in water; it
attrafts the moifture from the air, and becomes thick
57o and vifckL
Action of 2. When heated, it undergoes the watery fufion, then
heat. froths up, and becomes dry. When the temperature
2
I S T R Y.
is railed, it melts into a tranfparent glafs. The ful- Potafh, 8cc.
phuric, nitric, and muriatic acids decompofe this fait.
It has been applied to no ufe.
b. Phofphate of Potafh.—This fait may be_ formed
by expofmg pure potaih and the former variety to a
flrong heat. The alkali combines with the excefs of 971
acid, and neutralizes the whole. By the aaion ofAftionof
heat, a white-coloured fubltance is obtained, which is
the phofphate of potaih. It is fcarcely foluble in cold
water, but foluble in hot water ; and as the folution
cools, there is depofited a fhining gritty powder. This
fait is very fufible. Before the blow-pipe it melts in¬
to a tranfparent bead, which becomes opaque on cool-
ing. 97^
2. This fait is foluble in nitric, muriatic, and phof-Of acids,
pboric acids, and forms with them thick glutinous fo-
lutions. It has not yet been applied to any ufe.
10. Phofphite of Potafh.
This fait is prepared by diffolving carbonate of pot¬
aih in pbofphorous acid, dhe folution is evaporated,
and it depofits cryftals of the phofphite of fotafi. It
has a fharp faline taffe. It is cryftallized in four-lided
reftangular prilms with oihedral iummits. It is very
foluble in water, requiring only three parts of.it for
folution. It is not altered by expofure to the air.
11. Carbonate of Potaih.
1. This fait, which is a compound of carbonic acid
and potaih, has been known under a great variety of
names, in fome meafure deferiptive of its properties,
before its compofition was difeovered by Dr Black.
2. This fait is obtained from vegetable matters by Prepara¬
burning, and wadiing out the fait and evaporating it jtl0n*
but the potafh obtained in this way is not fully fatu¬
rated with carbonic acid. After it has been puri¬
fied from foreign ingredients, the faturated carbonate
of potaih may be prepared by expofing a pure folution
of potaih to carbonic acid gas, as it is dilengaged from
fermenting liquors. I he carbonate of potafh as it is
formed, cryftallizes in the folution. 1 he cryltals may
be taken out and dried v.pon unfized paper, and put
up in well-clofed bottles. Or it may be prepared by
palling a current of carbonic acid gas difengaged from
the carbonate of lime by an acid, into a folution o.
potafh, in tall narrow bottles. I he carbonate cryllal-
lizes at the furface of the liquid. It may alfo be ob¬
tained by the procefs of Berthollet, which is to difUl
with an unfaturated folution of potaih, folid carbonate
of ammonia, from"which the potaih carries off the car¬
bonic acid, white the ammonia is difengaged in the
ftate of gas. . . 974.
3. The carbonate of potaih cryftalbzes in quadran-Properties.
gular prifms, terminated by quadrangular pyramids.
It has a fweet alkaline tafte, and changes vegetable
blues to a green colour. 1 he carbonate of potaih re¬
quires very near four times its weight of water to dii-
folve it. At the boiling temperature it diffolves five-
fixths of its weight. It does not cryftalhze by cool¬
ing but only by flow evaporation. Pelletier has ob¬
ferved, that carbonate of potaih diffolved in boiling
water, gives out bubbles of carbonic acid gas, which
Ihews’that this fait lofes a portion of its acid at this
temperature. Its fpecific gravity is 2.012. When it
is expofed to the air, it foon efflorefees. When it is
deliquefccnti
C H E M
potafo, 6tc. deilquefcent, it is owing to part of the potafh being
1 ' unfaturated with carbonic acid.
4. When it is expofed to a ilight degree of heat, it
lofes its water of cryftallization. Part of its carbonic
acid alfo feparates from it, but the whole cannot be
driven off by this procefs. The laft portions adhere
with a very ftrong affinity.
5. When the carbonate of potafh is heated with ful-
phur at a high temperature, the acid efcapes in the
ffate of gas 5 and there is formed a fulphuret, at the
moment of the effervefcence produced by the extrica¬
tion of the acid.
6. All the acids hitherto difcovered, have the pro¬
perty of feparating the carbonic acid from potaffi,
and of forming with its bafe particular falts. This
fait lofes more than a third of its weight, by being
deprived of its carbonic acid. The component parts
of carbonate of potafh are, according to.
97 S
Adtion of
fceat.
975
Decompo-
fed by ful-
phur.
977
By all
adds.
Bergman,
Carbonic acid, 20
Potafh, 48
Water, 32
Pelletier, Kirwan,
43
40
17
43
41
16
100
100
100
I S T R Y. 563
7. Potafh of commerce is never faturated with car- Potafh, Sec.
bonic acid. It is in this date that the carbonate of v-—-J
potaffi is generally employed. It has a ftronger alkaline ef
tafte, and is more acrid and corrofive. It foon deli-comme rCe.
quefces when expofed to the air. It does not combine
wdth a greater proportion of carbonic acid, merely by
expofure to the atmofphere. For the purpofes of the
manufacturer it is of great importance to be able to af-
certain, by a fimple teft, the quantity of pure potaffi
in the different kinds which are brought to market. 579
Mr Kirwan has propofed to difcover the proportion ofTeftsofits
the fait, by determining the quantity of the earth ofPu“ty'
alum which is precipitated by the potaffi. A differ¬
ent method has been propofed by Vauquelin with the
fame view. His method is to faturate a given weight
of the fait with nitric acid of knowm denfity. He has
alfo made a number of experiments to difcover the
quantity of foreign ingredients in different kinds of
potaffi. The following table ffiews the kinds of
matter and the proportions in fix fpecies of pot¬
affi *• * dnn. dt
CbitH. xL
284,
Potaffi of Ruffia,
Potaffi of America,
Potalh.
772
857
Sulphate of
Potafh.
!54
Muriate of
Potafli.
Infohible
Refidue.
56
20
Carbonic
Acid and
Water.
254
119
Total.
1152
1152
American pearl-affi,
754
80
308
1152
Potaffi of Treves,
720
165
44
24
199
1152
Potalh of Dantzic,
603
I52
*4
79
304
1552
Potaffi of Vofges.
444
148
5io
34
304
I44°
j>8o
Prepara¬
tion.
9S1
Properties.
* Fourcroy
Cortnai/s.
V. Sc. *•
982
With more
acid cry-
ftallizes.
12. Arfeniate of Potaffi.
1. The compound of arfenic acid and potalh forms
a fait which does not cryllallize. When evaporated
to drynefs, this fait deliquefces in the air, gives a green
colour to fyrup of violets without changing the tinc¬
ture of turnfole.
2. When llrongly heated it fufes into a white glafsj
and by the contact of filica and alumina in the cruci¬
ble it paffes to the acidulous ftate, having been de¬
prived of part of the potaffi. Expofed to a red heat
in clofe veffels wuth charcoal, the arfenic is fublimed.
It is decompofed by the fulphuric acid. It decompo-
fes falts which have bafes of lime and magnefia $ form¬
ing in the folution arfeniates of lime and magnefia *.
Superarfeniate of potajh.—If the arfenic acid be
added to the arfeniate of potaffi till it no longer change
the colour of violets, but reddens that of turnfole, it
yields regular tranfparent cryftals in quadrangular
prifms, terminated by tetrahedral pyramids. This
fait is the arfenical neutral fait of Macquer. He ob¬
tained it by decompofing the nitrate of potaffi, by
means of the white oxide of arfenic, employing equal
parts of each. It is different from the former, be-
caufe it cryftallizes, reddens vegetable blues, and does
not dccompofe lalts with a bafe of lime or magnefia.
13. Tungftate of Potafh.
1. This compound of tungflic acid and potaffi, isprepa^
formed by diffolving the oxide of the metal in a folu-tion.
tion of pure potaffi, or its carbonate. The alkali is
not fully neutralized. The fait precipitates from the
folution by evaporation, in the flate of a white pow’-
der.
2. It is diftinguiflied by a cauftic metallic tafle, de- pr0perii«.
liquefces in the air, and is foluble in water. This fo¬
lution in water is decompofed by all the acids which
produce a white precipitate. This precipitate is a
triple fait, differing according to the nature of the acid
which is employed +. t Joum- de
r J ' Minet.n0
J4. Molybdate of Potaffi. 19.9.21.
I. The compound of molybdic acid and potaffi isprepara-
formed by detonating three parts of nitre and one oftien.
4 B 2 fulphuret
$36
Properties.
564 C H E M
Potato, &c. fulphuret of molybdena in a crucible •, or by combin-
1 ' ing direflly the molybdic acid with potaflr. This fait
affords fmall irregular cryftals, from its faturated folu-
tion in boiling water. According to Klaproth, the
cryftals are in the form of fmall rhomboidal plates, of
a ftiining appearance, and heaped together.
(i2. The tafte is metallic. When expofed to the
blow-pipe on charcoal, they fufe rapidly, without
fwelling up, and are converted into fmall globules,
which are abforbed by the charcoal. In a filver fpoon
they are melted by the blow-pipe into fmall gray par¬
ticles, which {brink, on cooling, and depofit, during
the procefs, a whitilh powder. This fait is complete¬
ly foluble in diftilled water with the afliftance of heat.
It has an excefs of acid, and is therefore an acidulous
molybdate of potaftr, or fupermolybdate of potafh. It
is decompofed by the nitric acid, which unites with
the alkali, and precipitates the molybdic acid in the
form of fmall cryftals *.
15. Chromate of Potafh.
Nothing farther is knoven of the nature of this fait,
than that it is eafily formed by the combination of the
chromic acid with potafh, and that the cryftals are of
an orange colour, which fufficiently diftinguifhes them
from the cryftals of all other falts.
I S T R Y.
4. This fait is decompofed by the ftrong acids. Di- Petato, Stc,
ftilled with the fulphuric acid, it yields an acetic acid 9^"
which is very acrid. The component parts of the ace-0ompOg.
tate of potafh are, according to Dr Higgins, tion.
38.5 Acid and water,
61.5 Potafh.
100.0
* Ann. de
Chim. viii.
p. 106.
f Phil.
Tranf.
180*. p. 58
987
Names.
988
Prepara¬
tion.
989
Properties.
99°
Adtion of
heat.
| Annul, de
Cbim- xlii.
p. 133.
16. Columbate of Potafh.
Columbic acid digefted for an hour with a folution
of potafh, affords this fait by evaporation and cooling,
in the form of white glitteting fcales, refemblmg the
concrete boracic acid. It is not changed by expofure
to the air, has a difagreeable acrid tafte, and is not
very foluble in cold water ; but after it is diffolved,
the folution is perfeft and permanent. _ It is decompo¬
fed by nitric acid, and precipitates in the form of
white powder f.
17. Acetate of Potafh.
1. This fait, which is a compound of acetic acid
and potafh, has been long knowm under a variety of
names, which were derived from the fubftances from
which it was obtained \ or, from its properties and ef-
fefls. It was called regenerated tartar, fecret foliated
earth of tartar, effential fait of wine, digejlive fait of
Sylvius, diuretic fait. It may be formed by faturatmg
carbonate of potafh with diftilled vinegar, and by eva¬
porating the folution flowly to drynefs. When the
heat is too great, the acid is decompofed, and the fait
affumes a brown colour.
2. This fait has a pungent, and fomewhat alkaline
tafte. Expofed to the air, it becomes moift. It is
very foluble in water, and if the folution be diluted,
it is fpontaneoufly decompofed in clofe veffels. Thick,
mucous flakes are depofited.
3. When it is heated, it melts and froths up, and
is then decompofed and charred. When diftilled in a
retort, it yields an acid liquid, an empyreumatic oil,
and a great deal of carbonic acid gas, and carbonated
hydrogen gas. In this procefs the acid is completely
decompofed j what remains in the retort is potafh mix¬
ed with charcoal. According to Prouft, this acid li¬
quid contains ammonia and the pruflic acid, and the
carbonate and prufliate of potafh are found in the re¬
tort
18. Oxalate of Potafh.
The compound of oxalic acid and potafh may be
formed by direft combination of the acid and the alkali.
The oxalic acid combines in two proportions with pot¬
afh, either in a fmall quantity, or in fufficient quanti¬
ty to faturate the potafh. When the acid is in ex¬
cefs, it is called the acidulous oxalate, ox fuperoxalate of ^
potafh. . Prepara-
1. The oxalate of potafh is formed by completely tion.
faturating the oxalic acid with potafh •, and by adding
an excefs of the alkali, cryftals are obtained.
2. Without this excefs of acid, the fait does not cry-
ftallize, but affumes a gelatinous form. . . pJSties
3. When this fait cryftallizes, it is in the formProPerties'
of fix-fided prifms, with two-fided fummits. It is
decompofed by heat, and alfo by the ftrong acids,
which deprive it of a portion of the potafh, and con¬
vert it into the acidulous oxalate. With an addition
of oxalic acid the acidulous oxalate is alfo formed. p94
Superoxalate of Pota/h.—i. This fait exifts ready Exifts in
formed in the runic* acetofa, and the oxahs acetofella ; plants,
hence it has been diftinguifhed by the name of Jalt oj
forrel becaufe it is extra&ed from this plant. 995
2. This fait may be formed by gradually combin-Preparav
ing potafh with a faturated folution of oxalic acid.tl0n*
When a fufficient quantity of the alkali has been add¬
ed, the fait is precipitated in cryftals. Scheele dif-
covered that the fait which is extrafted from thefe
plants, is in this ftate of combination. He proved the
exiftence of the acid, and he fhewed that the natural
fait might be imitated by this procefs. f r „ p ^
3. The cryftals of this fait are m the form of fmall Propertiea
opaque parallelepipeds. The tafte is acid, pungent and
bitter. It is not very foluble in cold water, but iolu-
ble in about ten times its weight of boiling water.
Expofed to the air, it undergoes no change. It is de¬
compofed by heat.
19. Tartrate of Potafh. ^
I This is a compound of tartaric acid and potafh.Prepara-
Ithas been long known under the name oifoluble tar-don,
tar, and vegetable fait. It is formed by adding tartar
or cream of tartar to a hot folution of carbonate of pot¬
afh The additions of the tartar are to be continued
as long as there is any effervefcence. The folution is
then boiled for half an hour, filtered and evaporated,
till a pellicle appears on the furface, and when it is
allowed to cool flowly, it depofits cryftals. 998
2. The cryftals of this fait are in the form oi iong,proi)ertu,s.
re&angular prifms terminated by two-fided fummits.
This fait has a bitter tafte. The pecific gravity is
, p r67. Expofed to the air it is deliquefcent. Four
parts of cold water diffolve one of the fait; hot water
diffolves a greater quantity. When heated, it fwells
up and blackens. By diftillation it yields an acid li¬
quid, fome oil, and a great quantity of gas. It,le.^
CHEMISTRY.
565
Fetafh fee.behind a confiderable portion of alkali, mixed with'
/-^charcoal. It is decompofed by the ftronger acids,
which deprive it of a portion of its potato, and reduce
it to the acidulous tartrate, which is precipitated in
the folution. By the addition of the tartaric acid to
the folution of this fait, it is alfo converted into the
999
Tartar.
1000
Purifica¬
tion.
1001
Contains
an alkali.
1002
Properties.
1003
Aftion of
heat.
1004
Compofi-
tion.
acidulous tartrate.
Supertartrate of Potajh.—t. This is a compound of
tartaric acid with potato, but with an excefs of acid.
The fubftance which is well known under the name of
tartar, and which is found encrufted on the bottom
and fides of veflels in which wine has been kept, is
the fupertartrate or the acidulous tartrate of potato ^
but in this ftate it is very impure. It is purified^ by
folution in boiling water, and by filtration while it is
hot. When it cools, there is a copious depofition of
the pure fait in cryftals. Thefe are the cryftals or cream
of tartar.
2. It had been long known to chemifts, that potato
could be obtained from tartar, by expofing it to a ftrong
heat, which produced a controverfy whether the alkali
exifted ready formed in the tartar, or whether it was
not, in fome way or other, produced by the aftion of
heat during the procefs. This point was not fully fet¬
tled till Scheele difeovered the method of extrafting
the acid, the other component part of tartar.
3. The cryftals of tartar are in the form of fmall
irregular cryftals, but chiefly of fix-fided prifms. This
fait has an unpleafant acid tafte, is very brittle, and its
fpecific gravity is 1.953. It requires for its folution
30 parts of boiling water, and 60 of cold water. It
undergoes no change when expofed to the air, but in
the folution in water the fait is decompofed, depofiting
a mucous matter, and leaving behind an impute car¬
bonate of the alkali.
4. Expofed to heat, it melts, fwells up, blackens,,
and the acid is totally decompofed. When it is (Mil¬
led, an oily matter, and an acid liquid, which is an
impure acetic acid, with a great quantity of carbonic
acid, are obtained. This acid was formerly called the
pyrotartarous acid (z).
5. The component parts of tartar, according to
Bergman, are
Acid 77
Potato 23
IOO
Or of the faturated fait.
Tartrate of potato 56
Acid 44
100
By the analyfis of Thenard, it is compofed of
Acid 57
Potafli 33
Water 7
* Ann. dt Q7 *
Cbim. ^1
xxxviii.
P- 39-       
20. Citrate of Potato.
Potafli, 8tc*
u ioo5
This compound of citric acid with potato may be Properties
formed by combining together 36 parts of the acid and com-
with 61 parts of the carbonate of the alkali. ThisP0^00'
fait is very foluble in water, but little difpofed to cry-
ftallize. It is very deliquefeent. According to the
analyfis of Vauquelin, it confifts of
Acid, 55.55
Potato, 44.45
100.00
31. Malate of Potafli.
This fait, which is a compound of malic acid and
potato, is deliquefeent, and very foluble in water, but
its properties are little known.
22. Gallate of Potato.
The compound of gallic acid and potato has little fo-
lubility in water, but its other properties are un¬
known.
23. Benzoate of Potato.
This fait, compofed of benzoic acid and potato, cry-
ftallizes on cooling, into fmall needles. A drop of
the folution fpread on the fide of the veflel, as it eva¬
porates, exhibits an arborefeent cryftallization. It
has a ftiarp faline tafte, is deliquefeent in the air, and
very foluble in water.
24. Succinate of Potafli.
This compound of fuccinic acid and potato, forms
cryftals in three-fided prifms •, the tafte is bitter and
faline j it deliquefees in the air, and is very foluble in
water.
25. Saccolate of Potato.
This is the compound of faclaftic acid and potato. It
forms fmall cryftals, which are foluble in eight times
their weight of boiling water,
26. Camphorate of Potato.
1. This fait, which is a combination of camphoric Prepara-
acid and potato, may be formed by faturating a folu-tion.
tion of carbonate of potato with camphoric acid.
When the effervefcence has ceafed, the. folution is to
be evaporated w’ith a gentle heat, when it affords cry¬
ftals by cooling. „ . . , r f 1007
2. The camphorate of potaui is in the torin or properties
lar hexagonal cryftals, which are white and tranfpar-
ent ; the tafte is bitterito and {lightly aromatic. Ex-
pofed to the air, when it is moift, the fait lofes its
tranfparency; but if the air is dry, there is no change.
It is foluble in four parts of boiling water; but in
water at the temperature of 6o°, it requires 100 parts. ioog
3. Expofed to heat before the bl©w-pipe, it burns ^(q.jon Qt-
with heat.
(z) The pyrotartarous acid, the pyromucous, and the pyroligneous adds were d^covered by Fourcroy^nd
Vauquelin to be nothing elfe than the acetic ac.d .mpregnated w.th extraneous fubflances, particularly w.u
what is called an empyreumatic oil. See jinnaks de Chwue} xxxv. p. i6j. ^
*
$66
^otafti, Sec.
loop
Of acids.
IOIO
Of alcohol.
ion
Pecompo-
fition.
* /Inn. de
Chim.
xxvii. p. 24.
10x2
Prepara¬
tion.
1013
Properties.
1014
Adtion of
Jieat.
f Ann. de
Chim. xxiii.
P- 52*
% Ibid.
xxxvi.
p. 2«S.
!l iiid.
xxxix.
P- 193-
C H E M
with a blue flame, and the potafh remains behind pure.
When the heat is ftronger, it froths up, the acid is
fublimed, and it gives out a thick fmoke, which is
fiightly aromatic.
4. It is decompofed by the mineral acids. If the
folution be much diluted with water, the decompofition
is not perceptible j but if brought to the confidence of
a thick fyrup, the camphoric acid cryflallizes in cool¬
ing. A new fait alfo is partially cryftallized. By fo¬
lution in cold wrater the acid may be feparated.
5. The camphorate of potalh is foluble in alcohol,
and it burns with a deep blue flame.
6. It is decompofed by, 1. Nitrate of barytes and of
filver 5 2. By all the falts whofe bafe is lime ; 3. Sul¬
phate of iron ; 4. Muriate of tin and of lead *.
27. Suberate of Potafh.
1. This fait, which is a compound of fuberic acid
with potafh, is formed by faturating the acid with the
cryftallized carbonate of the alkali.
2. It cryftallizes in four-fided prifms, which have un¬
equal fides. The tafte is bitter and faline. It reddens
vegetable blues, and is very foluble in water.
3. Expofed to heat, it fwells up and melts; the
acid is diffipated, and the potafh remains behind. . It
is decompofed by the mineral acids, which combining
with the potafh, precipitate the fuberic acid. It is de¬
compofed alfo by barytes, by all the metallic falts, by
fulphate and phofphate of alumina ; by the nitrates and
muriates of lime and of alumina f.
28. Mellate of potafh.
The mellitic acid combines with potafh, and forms
this fait, which is fully faturated with the acid, and in
this ftate it cryftallizes in long prifms ; but with an ad¬
ditional portion of acid, an acidulous mellate, or fuper-
mellate is formed. This fait, as Vauquelin obferves,
alfo cryftallizes ; but the properties of thefe falts have
not been much examined
29.. Ladlate of Potafh.
This fait is only known as being deliquefcent, and
foluble in alcohol.
30. Pruftiate of Potafh.
The compound of pruflic acid and potafh, is formed
by diffolving the alkali in the acid. The fait is very
foluble in water, produces a green colour on vegetable
blues, and, with the application of a moderate heat, it
is decompofed.
31. Sebate of Potafh.
This fait has been little examined. According to
the experiments of Thenard, it has little tafte, is not
affefted by expofure to the air, and is decompofed by
the fulphuric, nitric, and muriatic acids ; the folution,
if it be concentrated, becoming folid on the addition
of the acid from the cryftallization of the febacic
acid ||.
32. Urate of Potafh.
This compound of the uric acid with potafh, is form¬
ed by triturating the acid with the alkali. The mix¬
ture affumes the form of a faponaceous pafte, which is
very foluble in water, when there is an excels of the
I S T R Y.
alkali, but lefs fo when the acid is faturated. This Soda, &t.
fait has little tafte; when neutralized is not very foluble v J
in water, and feems little difpofed to cryftallize. It is
decompofed by the muxiatic acid *. Fourcroj
r v iuonnaijS9
IV. Compounds of Potafh with Inflammable Sub- Chim. x.
fiances. ^ 221*
1015
j. Potafh is very foluble ip alcohol. The folution Alcohol,
affumes a red colour, and becomes acrid. It is by a
folution of potalh in alcohol, that the former is obtain¬
ed in a ftate of purity ; for the alcohol diffolves the
potafh, while other fubftances are depofited. By the
application of heat to this folution, there is a partial
decompofition of the alcohol.
2. Ether has no perceptible aftion on potafh. I0I(j
3. Potalh readily enters into combination with the p;xeci 0iK
fixed oils, but particularly with that clafs of them de¬
nominated fat oils $ and forms with them very import¬
ant compounds, namely, foaps. The compound with
potafh and the fat oils is a foft foap. _ _ lor7
4. Potafh alfo enters into combination with the vo- y0iatlp.c
latile oils, but in very fmall proportion, which likewile
forms a fpecies of loap.
Sect. II. Of Soda and its Combinations,
1016
I. Soda, the other fixed alkali, has been diftinguifh-Names,
ed by a great number of different names. It was cal¬
led/#/or mineral alkali, becaufe it was fuppofed that
it only exifted in the mineral kingdom. It is the fub-
ftance w'hich is mentioned in fcripture as a detergent,
under the name of nitre. . _ 1019
This alkali exifls in great abundance in different Found in
parts of the earth, and particularly on the furface of foil-
the foil in Egypt, where it is diftinguiihed by the name
©f natron. It is alfo found on the walls of caves and
places under ground, and old edifices. _ _ I02O
But the foda of commerce is genei'ally obtained from Obtained
different fpecies of plants which grow on the fea-fhore ;from plants,
and as it is prepared from them, it has received dif¬
ferent names in different countries. Ihe falfola foda, _
yields this alkali in greateft abundance. 1 his plant
is called barilla in the Spanifh language, and from this
the foda which is prepared on the fhores of that country,
has been called barilla ajbes. For the purpofes o(
commerce alfo, foda is prepared in great quantities
from the afhes of another tribe of marine plants, namely
the alg/e, and particularly from the fua, all of which
yield it in greater or lefs proportion. As it is prepar¬
ed from thefe plants, it is knowm in France by the
name of varec, and in Britain by the name of kelp.
Soda exifts in great abundance in the waters of the
ocean. There it is in combination with the muriatic
acid, forming the well-known compound of common
fait. % , n 1021
3 In many of their properties foda and potafh ap- Firft di-
proach very near to each other. They were according- ftinguiflieJ
ly confidered as the fame alkali; till, towards the mid-
die of the 18th century, by the experiments of IJuha-
mel, Pott, and Margraff, they were diftinflly charac-
terifed, and the properties of each fully afcertained. I023
4. The foda of commerce is in very different degrees Purifka-
of purity, according to the care and attention withtioti.
which it is prepared, and the purpofes for which it is
intended. To have it perfeaiy pure, it muft be fub-
jected
I02J
Properties,
1024
Adlion of
beat.
1025
Of air and
water.
1025
A fimple
>-dubftance.
C H E M
Soda, See. je&ed to a fimilar fprocefs with thofe which have been
k—"Y—already detailed for the purification of potalh •, and
by means of tbefe proceffes it may be procured in a
folid and cryftalline form.
5. When foda is in a ftate of purity, it is ufually in
the form of folid plates, of a grayiih white colour,
and the tafte exactly fimilar to that of potafh. It is
alfo extremely cauftic and corrofive. By flow evapo¬
ration from a folution in alcohol, it affumes the form
of prifmatic cryftals j but thefe when expofed to the air,
very foon efflorefee, and fall to powder. Soda changes
the blue colour of vegetables to green. Its fpecific
gravity is 1.356. When it is expofed to heat, it fof-
tens, and readily melts. It liquefies by the aftion of
heat like an oily matter, and when it becomes red hot,
boils, and is reduced to vapour, which is the foda un¬
changed, extremely acrid, and corroding the ikin
when it comes in contafi: with it.
6. When expofed to the air, it firft becomes moift
and foft, by abforbing water and carbonic acid j but
when the air becomes dry, it efflorefees and falls into
a powder and in this refpedfl is fufficiently diftinguiflied
from potafh. Soda has a very great affinity for water.
When the dry alkali is moiftened with water, it is ab-
forbed, and becomes folid, with the extrication of ca¬
loric. When more water is added, it diffolves, and al¬
fo gives out heat, and a peculiar odour, which is no
doubt owing to a portion of the alkali raifed in the
ftate of vapour along with the water.
7. Soda, as well as potafh, is to be confidered as a
fimple fubftance 5 for no attempt which has yet been made
to decompofe it, has fucceeded. Supported by certain
analogies, Fourcroy is of opinion that foda is a com¬
pound of magnefia and azote *, and he thinks this
conjefffare derives fome degree of probability from the
conftancy with which magnefia accompanies foda in the
■waters, and different compounds, of which this alkali
makes a pait } efpecially in animal matters and marine
Conjectures produfHons. Vauquelin, he obferves, has detefted
abour its magnefia in confidtrable abundance in the allies of the
Jalfola foda ; and the fame earth is always obtained in
great quantity during the procefs for the extradlion
and purification of foda.
8. The affinities of foda are the fame with thofe of
potafh.
9. Soda is employed for many fimilar purpofes as
potifh. On account of fome of its qualities, it is pre¬
ferred to potafh in many manufactures, becaufe it is
lefs acrid and corrofive, and is therefore lefs apt to de-
ftroy the texture of animal and vegetable matters to
which it is applied.
I. Action of Phofphorus on Soda.
Phofpho- Soda fcarcely enters into combination with phofpho¬
rus. rus. There is no phofphuret formed either by the dry
or humid way ; but when phofphorus is boiled with a
pure folution of foda, phofphorated hydrogen gas is
evolved in the fame way as when it is treated with pot¬
afh.
II. A&ion of Sulphur on Soda.
Sulphur. Soda readily combines with fulphur by fimple tritu¬
ration, by fufion, and by the humid way. In the two
firit cafes, there is formed a fulphuret of foda, which
1027
compoli-
tion.
I S T R Y. 567
may he decompofed by heat, and by the acids, and Soda, &c,
which decompofes water in the fame way as the ful- v-"r
phuret of potafh. By the humid way there is formed
a hydrogenated fulphuret of foda, which has an ex¬
tremely fetid odour, and emits, by the a£b‘on of the
acids which decompofe it, fulphurated hydrogen gas,
Hydrofulphuret of Soda.
This may be prepared in the fame wray as the hydro¬
fulphuret of potafh. It forms a cryfiallized fait in the
fhape of four-fided prifms, terminated by quadran¬
gular pyramids. The cryftals are colourlefs, inodor¬
ous, and very foluble in water. When this fait is ex¬
pofed to the air, it deliquefees, and becomes of a green
colour. It is decompofed by the action of acids. So¬
da, it would appear, has lefs affinity for fulphur and
fulphurated hydrogen, than potaih.
III. Compounds of Soda with the Acids.
1. Sulphate of Soda.
x. This fait, which is a compound of fulphmic acid
and foda, is well known under the name of Glauber's
fait, from the name of Glauber, a German chemift,
who difeovered it, in examining the refiduum of the
decompofition of common fait by means of fulphuric
acid. It has alfo been called the admirable fait of
Glauber, vitriolated mineral alkali, and vitriol of foda. 1031
2. This fait may be obtained by the direft combi-Prepara-
nation of fulphuric acid and foda. But it is more com-tl0n-
monly prepared by the decompofition of muriate of fo¬
da or fea fait, by means of fulphuric acid. The folu¬
tion is then to be filtered, purified and cryftallized in
the ufual way. 1032
3. It cryftallizes by flow evaporation, in tranfparent,Properties,
fix fided prifms, terminated by two-fided fummits, but
the cryftals are feldom regular, and the fides of the * Ann.
prifms are furrowed. The tafte is cool, bitter, and
naufeous. ff’he fpecific gravity is 1.4457 *. ^
4. When it is expofed to the air, efpecially when A&ion 0f
the air is dry, it efflorefees, which is owing to the efcape air.
of the water of cryftallization.. It lofes about 0.3 of
its weight. It is very foluble in cold water, and it
requires only -fths of its weight of boiling water.
5. When it is expofed to heat, it melts, on account Of heat,
of the great quantity of water of cryftallization which
it contains, and this is called the aqueous fufion. Af¬
terwards it dries, when the water is evaporated. It
lofes about .58 of its weight. To melt it afterwards,
it muft be expofed to a red-heat long continued, which
is caPed the igneous fvfon. After it is cooled, it is
found to have iuffered no change. When water is ad¬
ded, it returns to its former ftete.
6. It is* decompofed by means of charcoal which
at a red-heat converts it into fulphuret of foda, by de- .
priving the acid of its oxygen. The component parts Compolft
of this fait, according to Bergman, are tlon-
Acid 27
Soda 15
Water 58
too
Bbt
* Nitbol.
^tour. iii.
P- 3*5-
1037
Properties.
X038
Adlion of
the air.
1039
Of water.
1040
Of heat.
1041
Oompoli-
*ion.
G H E M
But according to Mr Kirwan, it is compofed o£
Cryftallized. Dried at 7000.
23 C2 - C6
18.48 - 44
58 - O
Acid
Soda
Water
ioq.oo
100
1036
Difcovery.
It is decompofed by barytes ; and by potafli, but lefs
powerfully. Lime and ftrontites are alfo capable of
producing a partial decompofition in the humid way,
and in contaft with the air.
7. This fait is a good deal employed in medicine, as a
purgative •, in chemiftry, for the purpofe of decompofing
other fubftancesj and in thearts,for the extraction of foda.
2. Sulphite of Soda.
t. This fait, which is a compound of fulphurous
acid and foda, was firft taken notice of by Berthollet.
It is prepared by paffxng fulphurous acid gas into a fa-
turated folution of carbonate of foda. The fulphite of
foda is precipitated at firft, in a confufed mafs of very
fmall cryftals, which are re-difiblved in warm water,
and cryftallize again on cooling.
2. The cryftals of fulphite of foda are in four-fided
prifms, two broad, and two narrow, terminated by two-
fided fummits. They are perfectly tranfparent. The
tafte is cool and fulphureous. The fpecific gravity is
2.9566.
3. Expofedto the air, it effiorefces, and the pow¬
der formed on the furface is converted into a fulphate.
It is extremely foluble in water. Boiling water takes
up more than its own weight. It cryftallizes again
on cooling, but fometimes the folution is formed into a
fingle mafs when it is expofed to the air ; and if quick¬
ly cooled with agitation, it affords nothing but needle-
formed cryftals. This folution expofed to the air is
converted into the fulphate.
4. This fait readily undergoes the aqueous fufion *, if
the heat be increafed, a portion of fulphur is driven
off, and it is converted into a fulphate.
5. It is decompofed by means of the acids, which dif-
engage the fulphurous acid in the ftate of gas. The
pxymuriatic acid gas brought into contaft with a folu¬
tion of this fait in water, inftantly converts it into ful¬
phate. It is decompofed by barytes, lime and potaftr;
by the fulphates of lime, of ammonia, and of mag-
nefia.
6. The component parts of this fait have been found
by analyfis to be,
I S T R Y.
The tafte is cooling, but more bitter than that of the Soda, fee-
nitrate of potafti.   *  
3. The fpecific gravity is 2.0964. Expofed to the
air, it attraCls moifture in a flight degree. It is foluble
in three parts of cold water, and in lefs than its own
weight of boiling water. . # 1044
4. Wken it is thrown on red-hot coals, it decrepitates Heat,
{lightly ; it is not fo fufible as nitre, but it is alfo de¬
compofed, and gives out oxygen gas mixed with azotic
gas.
5. In its decompofitions it is fimilar to the nitrate of
potafli. It detonates, however, lefs powerfully with
combuftible bodies, and burns them with lefs facility.
It is decompofed by barytes and potafti. I0^
6. The proportions of its conftituent parts are, ac- Compofi-
cording to Bergman, t*on’
Acid 43
Soda 32
Water 25
Sulphurous acid
Soda
Water
31
18
51
100
It has not been applied to any ufe.
104a
Names.
Properties.
3. Nitrate of Soda.
1. This compound of nitric acid and foda was
formerly known by the name of cubic nitre, and rhom-
boidal nitre. It is prepared by the direfl combination
of the acid with the alkali; or by decompofing the
muriate or carbonate of foda by nitric acid.
2. It cryftallizes in the form of rhomboids and prifms.
1
100
According to Mr Kirwan,
Dried in a heat of 4000.
Acid 53-2*
Soda 40.58
Water 6.21
After being ignited.
57*55
42.34
co.oo
100.00
99.89 f.
* Niclok
your. iii.
p. 215.
4. Nitrate of Soda.
Chemifts are not acquainted with the properties of
this fait, although it is known to be formed after the
partial decompofition of nitrate of kfoda by means of
heat.
5. Muriate of Soda.
1. The muriate of foda, which is a compound ofCo^05n
muriatic acid and foda, of all the other falls, from its fait,
great abundance in nature, and its valuable ufes, was
the earlieft known under the name of fait. It has been ^^47
diftinguilhed by the names of common fait, kitchen fait,
fea-falt, and fometimes fal gem, or rock fait.
2. This fait, which is found in fuch abundance >nAb^ant
nature, is never formed by art. In fome parts of the m nature>
world it exifts in the bowels of the earth in large maf-
fes, from whence it is dug out, and limply reduced to
powder, to be applied to ufe. But to obtain it from the
waters of the ocean, in which it exifts in different propor¬
tion, according to the temperature, the climate, and other
circumftances, it muff be extrafled by evaporation,
which is effefted by different proceffes, according to
the ftrength of the folution, and the art of the manu¬
facturer. In fome parts of the world, all that is done
is to colled the fait as it forms on the fliores of the fea,
or on the rocks, by the evaporation of the water \ but,
in general, fome art is neceffary, even when the fait is
obtained by fpontaneous evaporation. On the coaits
of Trance, Spain, Portugal, and the fliores of the Me¬
diterranean, the fea water is admitted into ponds du¬
ring the flowing of the tide, and its return is pre¬
vented by fluices, which are ftiut. It is then evapo¬
rated by the heat of the fun; and, as this evaporation
is gradual and flow, the fait cryftallizes in large
cubes, and it is known in commerce by the name of
bay
C H E M
1050
Purifica¬
tion.
Soda, Sec. bay fah, from the circumftance of its having been form-
v ed in creeks and bays of the fea.
5yart49 3* But as this procefs can only be followed in thofe
climates where there is a fufficient degree of tempera¬
ture to promote the evaporation fpeedily; artificial
heat is generally employed in the manufacture of fait.
Sometimes the water is received in large ponds or flat
veffels, where it is allowed to evaporate for fome time
in the open air. It is afterwards boiled in flat iron
pans 5 and, during the boiling, the impurities w'hich rife
to the furface are removed. When the water is lufH-
ently concentrated by the evaporation, a pellicle forms
on the furface, which is the cryftallization of the fait.
This falls to the bottom, and another pellicle forms,
till the whole of the fait is cryftallized. The purity
of the fait and the fize of the cryftals depend on the
flow evaporation ; and hence it is, that the pureft fait,
as it is manufa&ured it Britain, is that which is called
Sunday [alt. T his is obtained from the laft quantity of
water, which is boiled on the Saturday night; and, as it
has time to cool fiowly, the evaporation is more gradual,
and the cryftals are purer and larger.
4. But in this ftate the muriate of foda is far from
being pure. A very ingenious method has been pro-
pofed for the purification of fea fait by Lord Dundon-
ald. 7 he falts with w?hich common fait is impregnated,
are more foluble in water than the fait itfelf, and they
diffolve in much greater proportion in hot than in cold
water. But common fait is nearly equally foluble in
both. On this principle, therefore, the procefs pro¬
ceeds : A quantity of fait to be purified is put into a
conical veffel or bafket, which is (lightly flopped at
the apex, fo that the w^ater may pafs through. A fa-
turated folution of common fait is then prepared. This
folution of fait is poured boiling hot over the fait in
tne bafket. It can difiolve none of the common fait
in the bafket, becaufe it is already faturated ; but, as
it pafles through, it diffolves the other falts, and carries
them along with it. It was found by experiment, that
a faturated folution of ilb. of common fait poured up¬
on 10 lbs. removes about j- of all the foreign falts with
which it is impregnated.
5. But, even after this procefs, the fait is not per¬
fectly pure for the purpofes of chemiftry. For this
purpofe it may be diffolved in four parts of cold wa-
ter. Filter the folution, to feparate any fubftances
W’ith which it is mixed. Pour into it fome drops of a
folution of foda, till no farther precipitate is obferved.
The fluid is then to be evaporated, and the fait, as it
forms on the furface in Imall cubical cryftals, may be
extradled 5 or it may be obtained in larger cryftals by
Ikw evaporation.
1051
By other
procefies.
It may alfo be purified, by dropping into a folution
of common fait, a folution of muriate of barytes, and
then of carbonate of foda, as long as any precipitate is
formed. The liquid may then be filtered and evapora-
ioj2 ted, till the folution cryftallizes.
Properties. 6. The muriate of foda cryftallizes in perfeft cubes 5
but from thefe there are feveral deviations in the form
of its cryftals. Sometimes the angles of the cubes are
truncated *, fometimes they are in the form of oflahe-
drons; which is the cafe when common fait is diilbl-
ved in human urine, and allowed to evaporate fponta-
neoufly. But the primitive form of the cryftal, as w'ell
ae of the integrant particle, according to Hauy, is
Vox,. V. Part II.
I S T R Y.
the cube. The tafte is fweetifli and agreeable, and Soda, &c.
is that which is properly called fait, with which all v—*
fimilar taftes are compared. 7 he fpecific gravity is
2*I2°- 1053
7. It undergoes no change by expofure to the air.
Common (alt attradls moifture from the atmofphere j a*r’
but this is owing to an impregnation of other falts
which are deliquefeent. Thefe falts are muriate of
magnefia, fulphate of magnefia, and fulphate of lime.
It is from thefe that it is to be purified by the pro- 1054
ceffes, which have been deferibed above. It is folu- water,
ble in little more than 2~ times its weight of water;
and it is almoft equally foluble in hot and cold wa¬
ter. ,
8. When it is expofed to a ftrong heat, it decrepi¬
tates and gives out its water of cryftallization. It
melts in a red heat, and rifes in the air in the ftate of
white vapour ; but it is unchanged ; for if this vapour
be collefted by condenfmg it in the cold, it is found to
poflefs all the properties of common fait.
9. I he muriate of foda is decompofed readily by DecompolW
fulphuric acid, as well as by feveral other acids whichtion.
have a ftronger attra&ion for its bafe than the muri¬
atic acid ; or by the aid of double affinity, when an
acid is in combination with a bafe, which at the fame Ic>5<i
time a£ls on the muriatic acid. It is by means of the
fulphuric acid that the chemift procures muriatic acidric aC:d'
from the muriate of foda. Sometimes the fait is de¬
compofed by the fame acid to obtain the foda. The
fulphuric acid combines wuth the foda, and forms ful¬
phate of foda, while the muriatic acid is difengaged,
and that it may not be loft, it is conveyed into a leaden
chamber, which contains a folution of ammoniac, where
it forms fal ammoniac. The fulphate of foda is ex¬
pofed to ftrong heat in a furnace, to drain off any
portion^ of fulphuric acid that it may contain. It is
then mixed with its owm weight of chalk, and half its
weight of charcoal in powder. The mixture is ftrong-
ly heated in a reverberatory furnace, and occafionally
ftirred to permit the efcape of gas and fulphur which
fly off. When the mafs cools, it becomes folid and
black. 1 he charcoal in deccmpofing the fulphuric
acid of the fulphate of foda, fets the fulphur free,
which combines with the lime of the carbonate of lime,
and is partly fublimed ; while a part of the carbonic
acid combines with the foda; fo that the produtt is a
mixture of carbonate of foda, of lime and charcoal, ana¬
logous to the foda of commerce. In this way 0.58 of
crude foda may be extra&ed. Other acids, as well as
the fulphuric, fuch as the acetic, the phofphoric, and
boracic, have been propofed to be employed with the
fame view ; or indeed, any acid which has a ftronger
affinity for the foda than the muriatic acid, and is not
decompofed with much difficulty.
10. But thefe proceffes are not fufficiently economi¬
cal to anftver the purpofes of the manufadiurer : Other
proceffes have, therefore, been propofed and tried with
the fame view ; but fcarcely any has fucceeded. This
fait is very readily decompofed by barytes and potafh,
which combines with the muriatic acid, and fets the
foda free *, but the expence of preparing thefe fubftances
far exceeds the price of the foda in the market, fo that
they cannot be employed to advantage. 10^
It has been propoled to decompofe fea fait by means By lime,
of lime, for obtaining the foda. Soda is feparated
4 C , from
57°
Soda, See.
C H E M I S
* Refearches
p. 59, and
ii a.
1058
23y lead.
1059
By iron.
1060
Compofi'
won.
from the acid by mixing the common fait with lime,
in the form of pafte, and by expofing it to moifture.
In a fhort time the foda appears on the furface m the
ftate of efflorefcence. Scheele, it is obferved by Ber-
thollet, was the firft who noticed the decompofition ot
the muriate of foda by means of lime. He explains
this decompofition by {bowing, that lime afts on .alts
with fixed alkaline bafes. It decompofes a fmall part
of the muriate of foda, with which it is in contact, and
the foda eliminated by this means, combines with the
carbonic acid of the atmofphere. ^ hercaarbonf e^f
foda efflorefees, fo that it oppoles all refiftance to the
aftion of the lime, and the decompofition of the muri¬
ate of foda continues until it is impeded by the quan¬
tity of muriate of lime formed. It is in this way that
the fame philofopher accounts for the formation ot io-
da in the foil of Egypt. The circumftances neceffary
for this are, I ft, A fand containing a great quantity
of carbonate of lime; 2d, moifture ; and 3d, muriate
of foda : and thefe circumftances are found to exiit in
thofe places where there is an abundant production ot
’ foda *. A manufaftory for the purpofe of extra£ling
foda from fea fait, by means of lime, was eftabhftied in
Common fait is decompofed for the purpofe of
obtaining the foda, by means of litharge. In a mix¬
ture of four parts of litharge, and one ot fea fait, with a
little water, in the courfe of a few hours, a decompo 1-
tion of the fait is effeaed. The muriatic acid of the
fait combines with the lead, and is precipitated ; while
the foda remains in the folution, from which it may be
feparated by filtration and evaporation. ^
It has been found too, that fea fait may be decom-
pofed by other metallic fubftances. Scheele obferved,
that iron produced this efted. By dipping a plate ot
iron in a folution of fait, and expofing it m a moift
place, it was incrufted with foda. From other experi¬
ments it appears, that this decompofition may be ef¬
feaed by means of copper and zinc.
12. Muriate of foda, according to Bergman, is com-
pofed of
Acid 52
Soda 42
Water 6
100
TRY.
6. Hyperoxyrauriate of Soda.
Soda, Src.
io6z
1. This fait is prepared in the fame manner as theprepara_
combination of this acid with potalh. It is, howxver, tl0n,
difficult to obtain it pure, as it has nearly the fame de¬
gree of folubility in water as the muriate of foda. It
is foluble in three parts of cold and lefs of warm water.
It is alfo foluble in alcohol, and it feeros to communi¬
cate a greater degree of folubility to the muriate of
foda. Iofi3
2. The cryftals of this fait are m the form of cubes, Properties.
or in rhomboids. It produces the fenfation of cold in
the mouth, and its tafte is eafily diftinguiffied from
muriate of foda. It is decompofed by heat, by com-
buftible bodies, and by acids, in the fame manner as
the hyperoxymuriate of potafti.
3. This fait is compofed of
According to Kirwan, when dried in the tempera¬
ture of 8o°, it is compofed of
Acid 38.88
Soda 5 3.co
Water 8.12
100.00
1061
lifts.
Hyperoxymuriatic acid 66.2
Soda 29.6
Water 4>2
10C4
Compofl-
tion.
100.0
7. Fluate of Soda.
* Phil.
fTranf.
1802, p.
144.
1065
jo. Common fait maybe regarded almoft as a ne¬
ceffary of life. It is the moft ufeful of all fubftances
for the prefervation of animal matters which are in¬
tended for food. It is probable that it is highly ule-
ful not merely as a feafoning for food, or which it is
one of the moft agreeable, but alfo to promote ks di-
geftion It is alfo employed in many arts, as in me¬
tallurgy, in dyeing, and in the enamelling of ftone-
ware.
1. This fait, which is a compound of fluoric acidPrepara-
and foda, is formed by faturating the acid with the al-tion.
kali. If the folution be evaporated till a pellicle ap¬
pears, cryftals of fluate of foda are obtained. 1066
2. ’Thefe cryftals are in the form of fmall cubes,Properties,
have a bitter and aftringent tafte, are not deliquefeent,
and not very foluble in water. They decrepitate on
hot charcoal, and melt before the blow-pipe into a fe-
mitranfparent globule.
3. The concentrated acids difengage the fluoric acid
with effervefcence. This fait is alfo decompofed by
limewater, barytes, and magnefia.
8. Borate of Soda.
1. This fait, a compound of the boracic acid and fo¬
da is formed by faturating the acid with the alkali ;
but nothing is known of its nature and properties. The
fpecific gravity is 1.1351. But the combination of io-
da with this acid, which is a natural produttion, has
been particularly examined.
Sub-borate of Soda, or Borax.
1. This fubftance has been long known. Indeed itniftory.
is fuppofed, that the ancients were acquainted with it,
and that they employed it for feveral purpofes, under
the name of chryfocolla which is mentioned by Plmy.
It received this name from them, it is fuppofed, from
knowing its property of foldermg gold and the other
metals. The name borax is derived from iome ot the
oriental languages. Although borax was the fubjeft
of refearch among the alchemifts and earlier chemms,
yet nothing was known of its nature and compofition,
till the beginning of the 18th century.. It was then
decompofed by Homberg, by expofing it to beat with
fulphate of iron. The acid was feparated by fublima-
tion and long after known by the name of xhtfedattve
falt'of Homberg. In 173* its real compofition was
difeovered by Geoffrey. He obtained the acid cry-
ftallized in the humid way. In 1748 Baron decom-
CHEMISTRY.
1068
Purifica¬
tion.
Sofia, See. pofed borax by means of tbe vegetable acids, and he
i—- completed the knowledge of its compofition, by form¬
ing it with the acid and the alkali. Bergman after¬
wards (hewed, that borax is a fait with excefs of foda ;
and to be neutralized, it requires one half of its weight
of boracic acid.
2. Borax is a natural production of the earth in many
parts of the wrorld. It is formed at the bottom af fome
lakes in Perfia, the Mogul territory, in Thibet, in
China and Japan. It has been alfo found in fome
lakes in Tufcany. In the Eaft Indies it is known un¬
der the name of tincal, and in commerce under that of
crude borax. In this (late the borax is in the form of
fmall, femitranfparent, greenidi cryftals, intermixed
with a greafy matter, of a dirty grey colour, and of a
fweetilh alkaline tafte.
3. The purification of borax was originally in the
hands of the Venetians ^ but it has fince been praftifed,
and now almoil exclufively, by the Dutch. Their
procefs is not exaClly known. Valmont-Bomare, who
vifited one of thefe places in Holland, fays, that 80
parts of purified borax are obtained from 100 of the
crude materials ; that to extraft the fait completely,
from eight to twelve folutions and cryftallizations are
neceffary ; that all the veffels employed in the purifi¬
cation of this fait, are either of lead, or covered with
lead : but he adds, that one part of the procefs was
concealed from him, and he fufpefts that lime water
may have been employed in this part of the procefs.
4. Borax, after being thus purified, is in the form of
compreffed fix-fided prifms with three-fided fummits.
The tafte is fweetifh, and perceptibly alkaline. It
changes the vegetable blues to a green colour. The
fpecific gravity is 1.742. It efflorefees (lightly in the
air, and is foluble in water. Twelve parts of w7ater at
the temperature of 6o° diflblve one of borax. Six
parts are only neceffary at the boiling temperature.
5. When borax is expofed to heat, it readily melts.
As the water of cryftallization flies off, it fwells up and
acquires a greater bulk, and affumes the form of a por¬
ous mafs. By this procefs it lofes more than one-third
of its weight, and in this (late it is called calcined bo¬
rax. When it is expofed to a red-heat, it is converted
into a tranfparent glafs, which is foluble in water.
6. Borax is decompofed by all the acids which have
a ftronger affinity for the foda. It is by means of the
fulphuric and the nitric acids, that boracic acid is
obtained from borax.
7. The component parts of borax, according to Kir-
wan, are
1069
Properties,
1070
Action of
fieat.
1071
Of acids.
1072
Cotnpoll-
tion.
Boracic acid
Soda
Water
17
47
Wes.
* Fourcroy
Connaifs.
Chim. iii.
P- 3*5-
It is fuppofed that only five parts of the foda are fatu-
rated with the acid, and that the other twelve parts
form the excefs of alkali which is contained in the fait.
8. Borax is much employed in the arts, as a flux
for metals, and to promote the foldering of the more
precious metals. It is alfo employed by the mineralo-
gift as a flux for treating minerals by the blow-pipe.
Calcined borax is employed in medicine as an abfor-
bent *,
9. Phofphate of Soda.
1. This compound of phofphoric acid and foda, was Hiftmy.
the firft difeovered of the combinations of phoipho-
ric acid. Margraaff .was the firft who extracted it
from human urine, then in combination with ammo¬
nia, forming a triple fait, which was known by the
name of fufible or microcofmic fait. Haupt after¬
wards obtained it feparate, and diftinguifhed it by
the name of fal mirabile perlatum, or w’onderful per-
lated fait, on account of its pearl-like colour. At
laft the younger Rouelle difeovered that foda was one
of its conftituent parts. By fome it was fuppofed,
that the acid was different from the phofphoric, be-
caufe no phofphorus could be obtained from it. To
this acid Bergman gave the name of perlated acid ;
but by the analyfis of Klaproth, it was proved that this
fait confifts of phofphoric acid and foda, with an excefs
of acid. _ 1075
2. This fait is prepared by faturating the liquid acid Prepava-
phofphate, which is obtained from burnt bones by tlon*
means of the fulphuric acid, with carbonate of foda,
which muft be added in excefs. The carbonate and a
little phofphate of lime are precipitated in the folution,
which mult be filtered and evaporated till a thin pel¬
licle appears on the furface. The phofphate of foda is
cryftallized by cooling. Or it may be obtained by
the diredt combination of phofphoric acid and foda,
which muft alfo be added in excefs. 1076
3. The phofphate of foda cryftallizes in lengthened Properties,
rhomboids whofe angles are often truncated, and fome-
times it affords rhomboidal.prifms, and feveral other
varieties. The excefs of foda is neceffary, to make it
affume a regular form, and thus it changes vegetable
blues to green. The fpecific gravity is 1.33. It has
a fweetilh, faline tafte, fimilar to that of common fait. I077
4. It effiorefees in the air, and is very foluble in Adlion of
water. Four parts of water at the temperature of 6o°, water,
and one half its weight of boiling water, are fufficient
to diffolve it.
107S
5. The phofphate of foda expofed to heat, under-of heat,
goes the watery fufion. In a red heat it melts, and is
converted on cooling, into a milky white glafs. By
the aiftion of the blow-pipe on charcoal, it melts into
a globule which is tranfparent while it is hot, but be¬
comes opaque on cooling, and affumes the polyhedral
form when it becomes folid. 1Q79
6. The fulphuric, nitric, and muriatic acids decora-of acids,
pofe it partially, and convert it into the acidulous phof¬
phate of foda. ic8o
7. Since the properties of this fait were difeovered, ufeS.
it has become an objed of confiderable importance, on
account of the various ufes to which it has been ap¬
plied. It was introduced into medicine by Dr Pear-
fon, and is found to be a mild laxative, particularly
agreeable on account of its tafte, as it may be taken in
broth, as a fubftitute for common fait. It is employed
by mineralogifts as a teft for the fufion of mineral lub-
ftances by the blow-pipe, and in foidering, as a cheap
fubftitute for borax.
10. Phofphite of Soda.
1081
I. This compound of phofphorous acid and foda, Prepara-
may be formed by the dired union of the acid andtion.
4 C 3 * alkali
CHEMISTRY.
1082
Properties.
10S3
Adlion of
heat.
1084
Conipofi-
tion.
1085
Hiftory.
alkali in folution ; and by evaporation cryftals may be
obtained.
2. This fait cryftallizes fometimes in four-fided
prifms with unequal faces j fometimes in long rhom¬
boids, or in the form of feathers. The tafte is cool
and fweetifh. It efflorefces in the air, and is foluble
in two parts of cold water, and little more foluble in
warm water j fo that it cryftallizes by evaporation
rather than in cooling.
3. It melts readily under the blowT-pipe, gives out
fine phofphoric light, and is converted into a glafs
which continues tranlparent while it is hot, but be¬
comes opaque wdien it cools.
4. The component parts of this fait are,
ig96
Prepara¬
tion.
Phofphorous acid
Soda
W ater
l6.2
23-7
60.0
100.0
1087
■Properties,
xo88'
A&’-on of
water.
1089
Of heat.
igneous fufion. It is fomewhat more fufible than the Soda, &c.
carbonate of potafli, which renders it preferable in the
manufacture of glafs.
6. In its decompofition by other fubftances, it is ex¬
actly fimilar to the carbonate of potafh. 1C^Q
7. The component parts of carbonate of foda are ac-Compofi-
cording to tion.
Kirwan.
Eere;inan. In cryftals. Dry.
Carbonic acid 16 14.42 40.05
Soda 20 21.58 59-86
Water 64 64.00 00.00
5. This fait is eafily decompofed by lime, barytes,
and magnefia. It decompofes the fulphates, nitrates,
and muriates of lime, of barytes, ftrontites, and mag¬
nefia. It has not yet been applied to any ufe.
11. Carbonate of Soda.
1. This fait, which is a compound of carbonic acid
and foda, was long applied to various ufes, before its
nature and compofition wrere known ; nor was it per-
feftly underftood till the difcovery of Dr Black, which
ftiewed the two ftates in which the alkali exifts ; in
the cauftic or pure ftate, and in the mild ftate, when
it is combined with fixed air, or carbonic acid. The
different names under which it is known, have been
already mentioned in treating of foda. It is found in
great abundance in Egypt, where it efflorefces on the
foil, and is diftinguifhed by the name of natron. In a
fimilar ftate of efflorefcence, the carbonate of foda is
found in fubterraneous places, and the walls of build¬
ings ; but it is chiefly extrafted, as has been already
obferved, from fea plants, efpecially from thofe which
belong to the genus fuci.
2. Carbonate of foda may be obtained by diffolving
a quantity of the foda of commerce with three or four
times its weight of pure cold water, and then by filter¬
ing the liquor, and evaporating till a flight pellicle is
foimed. This pellicle, which confifts of fmall cubes
of common fait, is to be removed. The heat is to be
continued as long as any pellicle is formed, after
which the liquid is fet by to cool, and the carbonate
of foda cryftallizes.
3. The form of the cryftals of carbonate of foda are
irregular or rhomboidal o&ahedrons, formed by two
quadrangular pyramids, truncated near the bafe, which
exhibits dicahedral folids, with two acute and two ob-
tufe angles. The tafte is {lightly acrid j it converts
vegetable blues to a green colour, and its fpecific gra¬
vity is 1 3591-
4. The carbonate of foda efflorefces very rapidly in
the air. It is foluble in two parts of cold, and little
more than its weight of boiling water. It cryftallizes
on cooling ; but to obtain regular cryftals, the eva¬
poration muft be flow and fpontaneous.
5. When expofed to heat, it undergoes the watery
fufion, and if the heat be continued, it paffes into the
100
100.00
99.91
1091
12. Arfeniate of Soda.
1. This is the compound of the arfenic acid with fo¬
da; and when the acid is faturated with the alkali, the
fait cryftallizes.
2. According to Scheele the form of the cryftals of
this fait is like thofe of the acidulous arfeniate of pot¬
afh. Pelletier obferves that the arfeniate of foda cry¬
ftallizes in fix-ftded prifms, terminated by planes per¬
pendicular to their axis. In other refpefts it is fimi¬
lar to the arfeniate of potafh, being decompofed by
charcoal, by the acids and the earths. With an ex-
cefs of acid, it does not cryftallize, but becomes deli-
quefcent.
13. Tungftate of Soda.
1. This fait, which is the compound of tungftic Prepara-
acid and foda, may be formed by diffolving the oxide tion.
of tungften in a folution of pure foda, or carbonate of
foda. By evaporating the folution, cryftals of tungftate
of foda are obtained.
2. The cryftals of this fait are in the form of elon- pr0pertie&.
gated, fix-fided plates. The tafte is acrid and metallic.
It is foluble in four times its weight of cold water ;
and boiling water diffolves one half of its weight. It
reftores the colour of turnfole which has been redden¬
ed by an acid. 1093
3. This fait is decompofed by the fulphuric, nitric, Aftion of
muriatic, acetic, and oxalic acids. They form a white aCl^s-
triple fait, which is alfo produced by lime water. The
phofphoric acid produces no change, and if the ful¬
phuric acid be afterwards added, it no longer caufes a
precipitate. The tungftate of foda is not decompofed
by the fulphate of potafh or of magnefia. The muri¬
ates of lime and barytes occafion a white precipitate.
The folution of tin, and all other metallic folutions, al¬
fo decompofe it *. * Jour, do
Mines,
14. Molybdate of Soda? I9*
P. 21.
15. Chromate of Soda.
The chromic acid combines with foda, and forms s
fait, the cryftals of which are of an orange colour, but
its other properties are unknown.
16. Columbate of Soda.
Columbic acid enters into combination with foda,
but little is known of its properties.
17. Acetate of Soda.
1. The combination of the acetic acid with foda was Prepara-
formerly tkm.
C H E M
Soda, See. formerly known by tbe name of cryjlallixcd foliated
earth. This fait is prepared by faturating the acetic
acid with carbonate of foda. The folution is then fil¬
tered, and evaporated till a (light pellicle appear on
the furface ; and when it is fet by to cool, cryftals are
1095 depofited.
Properties. 2> The cryftals of acetate of foda are in the form of
ftriated prifms, like thofe of fulphate of foda. It has a
bitter, pungent tafte, is not deliquefeent in the air, and
is foluble in about three parts of cold water. The fpe-
cific gravity is 2.1. When expofed to heat it is de-
compofed, being firft deprived of its water of cryftal-
lization. After diftillation, the refiduum has the pro¬
perty of phofphorus. It is decompofed by barytes and
^ Fourcroy potaftr *.
Connalfs.
Chi?n. Viii. Oxalate of Soda.
The oxalic acid is capable of forming an acidulous
fait with foda ; but when it is fully faturated, the oxa¬
late of foda thus formed, is difficult of cryftallization.
If two parts of cryftallized carbonate of foda are dif-
folved in one part of oxalic acid, part of the oxa¬
late of foda is precipitated, and what remains in
the folution, being evaporated, affords cryftals in
the form of fmall grains. This fait is more folu¬
ble in warm than in cold water, and gives a green
colour to the fyrup of violets. It is decompofed by
potafti. In other refpe&s it refembles the oxalate of
potaftr.
19. Tartrate of Soda.
This compound of tartaric acid and foda, is form¬
ed by faturating the acid with the alkali. The form
of the cryftals of this fait is that of fine needles.
The fpecific gravity is 1.7437. This fait combines
•with another portion of acid, and forms an acidulous
tartrate or fupertartrate of foda, which is not more fo¬
luble in water than the acidulous tartrate of potafti.
20. Citrate of Soda.
T. This fait, which is a compound of citric acid and
loda, is formed by direftly combining the acid and al¬
kali.
2. It cryftallizes in fix-fided prifms which are not
terminated by a pyramid. It has a faline tafte, effio-
refees in the air, and is foluble in two parts of water.
When heated it boils up, fwells, and is charred. It is
decompofed by barytes and lime water. It is com-
pofed of
Acid 60.7
Soda 39.3
100.0
21. Malate of Soda.
This fait, formed of malic acid and foda, is deli¬
quefeent in the air, and very foluble in water. Its
other properties are unknown.
22. Gallate of Soda.
The nature of the compound of gallic acid with
foda has not yet been afeertained. A green colour-
is produced, when the alkali is dropt into the acid.
1 s T R Y.
23. Benzoate of Soda.
573
Soda, Sccr.
The compound of benzoic acid with foda, forms a
fait which readily cryftallizes. It is deliquefeent in
the air, and very foluble in water. The tafte is (harp
and faline. This fait exifts ready formed in the urine
of graminivorous animals.
24. Succinate of Soda.
The combination of fuccinic acid with foda, form?
beautiful tranfparent cryftals by fpontaneous eva¬
poration. The cryftals are in the form of four-
fided prifnis with two-fided fummits. The tafte of
this fait is bitter. It is not deliquefeent in the air, and
it requires about three times its weight of water to dif-
folve it. It is decompofed when it is expofed to heat
in clofe veffels.
25. Saccolate of Soda.
All that is known of this fait is, that it cryftallizcs
in fmall cryftals, and is foluble in five times its wreight
of boiling water.
26. Camphorate of Soda.
1. This compound of camphoric acid with foda is
formed by faturating a folution of carbonate of foda
in water with the acid ; and by evaporation with a
gentle heat, the cryftals are obtained, when the folu¬
tion cools.
2. The cryftals of camphorate of foda are irregular.
They are white and tranfparent. The tafte is bitter.
Expofed to the air, this fait efflorefees. It is foluble
in eight parts of boiling water.
3. Expofed to heat, it melts and fwells, and the
acid is diflipated in thick vapours of an aromatic
odour. With the blow-pipe it burns with a blue flame,
and is decompofed. The acid is fublimed, and the
alkali remains behind. It is decompofed by potafli,
and by the ftrong acids *. * ^
2 7. Suberate of Soda. Chim. xxvin-
p. 28.
The compound of fuberic acid with foda, forms a
fait which does not cryftallize. It has a (lightly bitter
tafte, and reddens the tindlure of turnfole. It deli-
quefees in the air, and is very foluble in wrater. Ex¬
pofed to heat, it fwells and melts ; the acid is fub¬
limed, and the alkali remains behind. The mineral
acids decompofe it, and it is alfo decompofed by the
calcareous, aluminous and magnefian falts f. \ IbU. xx"*
28. Mellate of Soda. P- 53-
The compound of mellitic acid with foda, when
it is faturated, forms cryflals in cubes or three-fided
tables. Sometimes they are formed in groups, and
fometimes they are infulated.
29. Ladlate of Soda.
All that is known of this fait is, that it does not
cryftallize, but is foluble in alcohol.
30. Prufliate of Soda.
This fait, which is a compound of pruftic acid'
and foda, is very foluble in water, converts vegetable
blues to green, and when it is expofed to a very mo¬
derate heat, it is partially decompofed.
13. Sebafce
574
Amnonia,
6cc.
1095
Hiftory.
1097
Prepara¬
tion.
1098
Properties.
C H E M
31. Sebatc of Soda.
Nothing farther is known of the compound of fe-
bacic acid with foda, than that it is foluble in water.
IV. Compounds of Soda with Inflammable Subftances.
1. Soda enters into combination with alcohol, and
forms a reddifh coloured acrid folution ; but when
heat is applied to this folution, it appears that the al¬
cohol is partially decompofed.
3. There is no aftion between ether and foda.
3. Soda readily combines with the fixed oils, and
efpecially that clafs of them called fat oils, and forms
with them compounds called foaps.
4. Soda combines in very fmall quantity with the
volatile oils, and the compounds thus formed have fome
of the properties of foap.
Sect. III. Of Ammonia and its Combinations.
1. This fubftance has been long known under the
names of volatile alkali, volatile fpirit of fal ammoniac,
canjlic volatile alkali, hartjhcrn, fpirit of hartfhorn and
of urine, becaufe it was obtained from thefe fubftances.
It has received the name ammonia, from fal ammoniac,
a fait which was extradled from the urine and dung
of camels, collefted near the temple of Jupiter Am¬
mon in Africa. This fait was unknown to the ancients.
Jt is firft mentioned by Bafil Valentine, who lived in
the 15th century, as being prepared from certain fub¬
ftances, with an account of fome of its properties. But
the difference between the pure fait and its compound
with the carbonic acid was not known till the difco-
verv of Dr Black. It was fuppofed to be in the ftate
of greateft purity in the folid and cryftalline form and
in its pure, cauftic, and liquid ftate, it was fuppofed to
be changed, and contaminated with the lime or the dif¬
ferent matters which had been employed in extracting
it from fal ammoniac. It was afterwards examin¬
ed by Dr Prieftley in the ftate of gas, and he decom¬
pofed it by eleftricity, but without difcovering its con-
ftituent parts. This was at laft effeCted by the re-
fearches and experiments of Scheele and Bergman,
and finally confirmed by thofe of Berthollet.
2. Ammonia may be obtained by the following pro-
cefs. Three parts of quicklime, and one part of fal-
ammoniac reduced to powder, are to be put into a re¬
tort, and the beak of the retort immerfed under mer¬
cury in the mercurial apparatus. A jar filled with
mercury is inverted above it. Heat is applied to the
retort, and a gas comes over in great abundance. This
gas is ammonia, or ammoniacal gas. Sal-ammoniac
confifts of the muriatic acid and ammonia. The affini¬
ty of lime for muriatic acid is ftronger than that of am¬
monia, and therefore the ammonia is difengaged in the
ftate of gas, while the lime combines with the acid.
The gas muft be received over mercury, becaufe it is
readily abforbed by water.
3. Ammonia in the ftate of gas refembles common
air. It is tranfparent and colourlefs, and may be in¬
definitely compreffed and dilated. The fmell is ex¬
tremely pungent and acrid, particularly irritating the
eyes and noftrils. It has an acrid and cauftic tafte,
but is much lefs corrofive than the other alkalies. It
1 s T r Y.
changes vegetable blues to a green colour. It is light- Ammonia,
er than common air. Its fpecific gravity is c.000732 ; , ^
fo that it is nearly one half lighter. According to Mr v
Kirwan, a cubic inch of this gas weighs only .27 of a
grain.
It is totally unfit for refpiration. No animal can
breathe it without inftant death. It is alfo unfit for
the fupport of combuftion ; but although it extinguifhes
burning bodies, the flame of a candle let dowm into this
gas, is confiderably enlarged in volume by the addition
of another flame, which is of a pale yellow colour. 1099
4. This gas is unaltered by the adtion of light. Adtion of
When it is expofed to a ftrong heat, as when it is paf-heat*
fed through a red-hot porcelain tube, it is decompoied
and converted into azotic and hydrogen gafes. It is
alfo decompofed by the eledlric fpark. When it is ex¬
pofed to the temperature of —450, it is condenfed, and
affumes a liquid form ; but it returns to the gafeous
ftate by an elevation of temperatuife. IIOO
5. There is no adlion between oxygen gas and this of oxygen,
gas in the cold ; but if the twro gafes mixt together are
made to pafs through a red-hot porcelain tube, the
ammonia is decompofed j a detonation takes place, the
hydrogen combines with the oxygen and forms water.
The azote paffes off in the ftate of gas. IIor
6. There is no adlion between > this gas and azotic Common
gas, nor is there any aftion between common air and air.
ammoniacal gas in the cold ; but if the mixture be
made to pafs through a red-hot porcelain tube, water
is formed, and the gas which efcapes is a combination
of the azotic gas of the atmofphere, and of that which
entered into the compofition of ammonia. But if the
fame experiment be made with a greater proportion oi* Fourcrt^
oxygen gas, the product is nitric acid, which is formed
by tbe combination of part of the oxygen and the ’
azote*. _ .1x02
7. It has been already mentioned, that the confti-compofi-
tuent parts of ammonia were difcovered by Scheele lion,
and Bergman, and Prieftley and Berthollet. Acccording
to the experiments of the latter, ammonia is compofed
of 121 parts of azote, and 29 of hydrogen. This re-
fult was obtained by decompofing the ammonia by
means of ele£lricity. One hundred parts of ammonia,
therefore, are compofed of
Azote
Hydrogen
80
20
100
. , 1103
8. Ammoniacal gas combines very rapidly with wa-of water,
ter. If a bit of ice be brought into contadl with this
gas, it abforbs and condenfes it, and inftantly becomes
liquid. There is at the fame time a produdlion of
cold ; but water in the liquid ftate, as it abforbs this
gas, becomes w7arm, becaufe the gas is deprived of that
quantity of caloric which is neceffary to retain it in
the gafeous form. The water, as it abforbs the gas,
becomes fpecifically lighter. When water is faturated
with this gas, it is known under the name of liquid
ammonia. The fpecific gravity of a faturated folu¬
tion is 0.90^4. When this folution is expofed to the
temperature of 130° the ammonia is driven off, and
affumes the gafeous form 5 and when it is flowly and
gradually cooled to the temperature of from —35 to
Ammonia,
&c.
Ann. di
Chim. xxix.
}>•
C H E M I
—42®, it cryftallizes J but when the temperature is ra¬
pidly diminifhed to—58° it affumes the form of jelly.
At that temperature it has no fmellf,
By Mr Davy’s experiments, a faturated folution of
ammonia contains, in 100 parts,
Water 64.63
Ammonia 25-37
100.00
} Davy's
Jlefearchcs,
j>.68.
He has alfo afcertained the different proportions of
water and ammonia which are contained in 100 parts
of liquid ammonia of different fpecific gravities
Thefe are exhibited in the following table.
Table of the quantities of Ammonia, fuch as extfts in
the aeriform fate, faturated with water at 5 2°, in
Aqueous ammoniacal Solutions of different fpecifc gra¬
vities.
100
Specific gra.
9°54
9166
9255
9326
9385
9435
9476
9513
9545
9573
9597
9619
9684
9639
97*3
Ammoniac.
25>37
22.07
19,54
17.52
5,88
H53
i3>46
12,40
11,56
10,82
10,17
9,60
9 >50
9.09
7>I7
Water.
74.63
77,93
80.46
82,48
84,12
85.47
86,54
87,60
88,44
89,18
89.83
90,40
90,5
90,91
92>83
' 1104
Affinities.
TI05
With heat.
S T R Y. 575
and fulphur. By this procefs a liquid of a deep orange Ammonia,
colour, which exhales extremely fetid vapours, on ac- ^ ^
count of the excefs of ammonia which it contains, is
produced. This was known under the name of the
fuming liquor of Boyle. This fulphuret is decompofed
by heat, by the acids and fulphurated hydrogen gas.
2. When ammonia abforbs fulphurated hydrogen gas,
either by agitating the gas in a veffel with liquid am¬
monia, or by pafling a current of the gas through it,
there is an evolution of caloric and the formation of
vapour, and the liquid is converted into an orange co¬
lour. This is the hydrofulphuret of ammonia. It has
no longer the fetid odour of the hydrogenated fulphu¬
ret, and it may be cryftallized. It is decompofed by
the a£Uon of heat, by the acids, and by the metallic
oxides.
III. Compounds of Ammonia with the Acids.
1. Sulphate of Ammonia.
1106
9. The order of affinities of ammonia is the fame
as the fixed alkalies.
I. Adfion of Phofphorus on Ammonia.
1. There is no affion between ammonia and phofpho¬
rus in the cold •, but when the two gafes are palfed
through a red-hot porcelain tube, the ammonia is de¬
compofed, and its conftituent parts enter into combi¬
nation with the phofphorus. There is formed phof-
phorated hydrogen gas and phofphorated azotic gas.
In this cafe, there is a double action of the phofphorus,
one part combining with the hydrogen, and another
with the azote.
2. Ammonia is alfo decompofed by red-hot charcoal,
when it paffes over in the ftate of gas at this tempe¬
rature. Part of the carbone of the charcoal combines
with the ammonia, and forms pruffic acid.
II. Aftion of Sulphur on Ammonia.
1. Ammonia combines with fulphur in the ffate of
vapour. This combination conftitutes a fulphuret of
ammonia, which has the property of decompofing wa¬
ter, and is then converted into a hydrogenated fulphu¬
ret of ammonia. This may be prepared by diftilling
in a retort, a mixture of muriate of ammonia, lime,
1. The compound of fulphuric acid wdth ammonia Hiftory.
was formerly called fecret fal ammoniac of Glauber, be-
caufe it was difcovered by that chemift. It was alfo
called vitriolated ammonia, and vitnolated volatile alha~
U. It was difcovered by Glauber in examining the
refiduum of the decompofition of ammonia by means
of fulphuvic acid. *107
2. This fait may be formed by faturating thp acid prePara*
with the alkali, and afterwards cryftallizing it. ^ jioS
3. The cryftals of fulphate of ammonia are fix-fided Properties,
prilins with unequal fides, terminated by fix-fided pyra¬
mids. The fulphate of ammonia undergoes little
change in the air. It {lowly attra&s moifiure in a
humid atmofphere. It is foluble in two parts of cold
tvater, and in a fmaller quantity of boiling water. TIOp
4. When expofed to heat, it melts } and if the heat Aftion of
be continued, it lofes a part of its bafe, and is convert-he^*
ed into the acidulous fulphate of ammonia. This dif¬
fers from the fulphate by its iharp tafte, and its proper¬
ty of reddening vegetable blues, greater folubility, and
a different aftion on feveral compounds.
5. This fait is not decompofed like the other ful-
phates, on account of its greater volatility. The com¬
ponent parts of this fait, according to Mr Kirwan. are,
Acid
Ammonia
Water
54,66
14.24
31-10
100.00
1. Sulphite of Ammonia.
mo
1. The compound of fulphurous acid with ammonia Prepara-
is prepared by pafling a ftream of fulphurous acid gastion.
into a veffel with liquid ammonia. The gafeous acid
is readily abforbed, much heat is produced, and the
fulphite of ammonia cryftallizes on the cooling of the
faturated folution. tin
2. This fait is in the form of fix-fided prifms termi- Properties
nating in fix-fided pyramids, or in that of four-fided
rhomboidal priims, with three-fided fummits. The
tafte is at firft cool and pungent, and afterwards fulphu¬
rous. It is deliquefcent in the air, from W'hich it ab¬
forbs oxygen, and is converted into the fulphate. It is
foluble in its own weight of cold water. The folution
produces
S7C
CHEMISTRY.
Ammonia,
Stc.
mz
Compofi-
tion.
1113
Hiftory.
1114
Prepara¬
tion.
1115
Properties.
iniS
A&ion of
water.
1117
X)f heat.
produces a great degree of cold. Boiling water dif-
folves Hill more. Water faturated with fulphite of
ammonia, and agitated in the open air, prefents this
fait in a few hours converted into the fulphate, without
any cruft on the furface, or muddinefs in the liquid,
becaufe it is very foluble in water.
3. It decrepitates flightly on red-hot coals : when it
is gradually heated in a clofe veflel, it gives out at firft,
water and ammonia, and then fublimes totally in the
ftate of acidulous fulphite.
4. The conftituent parts of this fait are,
Sulphurous acid 60
Ammonia 29
Water n
100
3. Nitrate of Ammonia.
1. This compound of nitric acid and ammonia, was
formerly called nitrous fal ammoniac, injlammable nitre.
This fait has been particularly examined by Berthollet,
and more lately by Mr Davy.
2. Nitrate of ammonia is prepared by direftly com¬
bining the acid and the alkali, and it may be obtain¬
ed in cryftals by careful evaporation and flow cool-
ing.
3. This fait cryftallizes in flx-fided prifms, termi¬
nating in long fix-fided pyramids; but the appearance
of the cryftals varies with the temperature in which
the evaporation goes on. Sometimes they are in long
filky threads, foft and elaftic j the tafte is very acrid,
bitter, and penetrating j and the fpecific gravity is
1.5785.
4. When the nitrate of ammonia is expofed to the
air, it attrafts moifture, and deliquefces. It is foluble
in two parts of cold water. Boiling water diflblves
double of its own weight.
5. Nitrate of ammonia very readily undergoes the
watery fuflon. If the heat be continued, it is entirely
deprived of its water of cryftallization ; and when the
temperature is increafed, it explodes fpontaneoufly,
giving out at the fame time a brilliant white flame,
with confiderable noife *, it is then entirely diflipated in¬
to vapour. This detonation inftantaneoufly takes
place, when the nitrate of ammonia is thrown on a
red-hot iron. It was from this property that the fait
derived its name of inflammable nitre. The nature of
this rapid combuftion will be underftood by confider-
ing the component parts of the fait. The hydrogen of
the ammonia enters into combination with the oxygen
of the acid ; water is formed, and azotic gas is difen-
gaged from each of the component parts of the fait.
In the different ftates of cryftallization, this fait re¬
quires different temperatures for its fufion and decom-
pofition. The following are the conclufions from Mr
Davy’s experiments.
“ a. Compact or dry nitrate of ammonia undergoes
little or no change at temperatures below 260°.
“ At temperatures between 275° and 300°, it
Ammonia,
SsCC.
flowly fublimes without decompofition, or without be¬
coming fluid.
“ c. At 3 20° it becomes fluid, decompofes, and ftill '■ "v 'r
flowly fublimes *, it neither affuming, nor continuing
in, the fluid ftate, without decompofition.
“ d. At temperatures between 340° and 480°, it
decompofes rapidly.
“ e. The prifmatic and fibrous nitrates of ammonia
become fluid at temperatures below' 300°, and undergo
ebullition at temperatures betwreen 360° and 400°,
without decompofition.
“ f. They are capable of being heated to 430°
without decompofition or fublimation, till a certain
quantity of their wrater is evaporated.
“ g. At temperatures above 450°, they undergo de- *^ejea)Cj}e.
compofition wflthout previoufly lofing their water ofp. $5. *
cryftallization IIl8
6. The component parts of nitrate of ammonia are, Compofi-
according to
Acid,
Ammonia,
Water,
Kirwan,
57
23
20
Fourcroy,
46
40
H
100
Mr Davy has afcertained the proportions of the com¬
ponent parts of this fait in its three difterent ftates f. f Ibid.
p. 7*.
Acid,
Ammonia,
Water,
Fibrous.
72.5
19-3
8.2
100.0
Prifmatic.
69-5
18.4
I 2.1
100.0
Compadt.
74-5
19.8
5-7
100.0
I Ilf
9. This fait has been applied to no ufe, but for theUfes.
purpofes of chemical experiment, and efpecially for the
preparation of the nitrous oxide or gafeous oxide of
azote, which has been already defcribed in treating of
the compounds of azote.
4. Nitrite of Ammonia.
If this fait be formed by depriving the nitrate of
ammonia of part of its acid, it muft be extremely diffi¬
cult, Fourcroy obferves, to obtain it in this way, be- f Connaifs.
fore the fait is totally decompofed Chim. iii
p. 160.
5. Muriate of Ammonia.
1 r • 1120
I. The compound of muriatic acid and ammonia Hiftory.
has been known, from time immemorial, by the name
oifal ammoniac. It derives this name from Ammo¬
nia, a country of Libya, w'hich name is defcriptive of
the fandy foil of that region (a). Hence too is the
origin of the epithet given to Jupiter, to whom a tem¬
ple was eredfed in that country. This fait was origi¬
nally colledled in great quantities near this temple,
where it was formed in the fand from the excrementi-
tious matters of different animals, particularly camels.
It was w'ell known to the Greeks and Romans, and
was employed by them in feveral arts. Before the na¬
ture
(a) From the Greek word ctppos, which fignifiesyh/;^.
Ammonia.
Sec.
1121
Purifica¬
tion.
TI22
Properties.
1123
A&ion of
water.
C H E M
ture o£ this fait was known, it was chiefly brought
from Egypt but it is now found to exift, ready form¬
ed, in different countries, particularly in the vicinity
of volcanoes, where it feems to be fublimed. It is
found alfo in the mountains of Tartary and Thibet, in
grottos in the neighbourhood of Puzzuoli, and diffolv-
ed in the waters of fome lakes in Tufcany. The na¬
ture of the muriate of ammonia was firft difeovered
by Geoffrey $ it was afterwards more accurately exa¬
mined by Duhamel $ and, at laft, its properties were
fully developed by Black, Bergman, and Scheele, Ber-
thollet and Fourcroy.
2. The muriate of ammonia, which is found ready
prepared in nature, is extremely impure. It muff
therefore be fubje&ed to feveral proceffes, to feparate
the foreign matters with which it is impregnated. The
fait which is found fublimed in the crater of volca¬
noes, is generally mixed with arfenic and fulphur.
In Egypt it is prepared by colle&ing together the ex¬
crements of animals which feed on faline plants.
Thefe fubftances are dried and burnt in furnaces which
are conftrufted on purpofe, or ufed as the common
materials of fuel. The foot which is thus formed, is
colle&ed, and put into large glafs bottles, and ex-
pofed to a ftrong heat, which is gradually increafed
for 72 hours. Towards the fecond day the fait is fu¬
blimed, and attaches itfelf to the upper part of the
bottles. When the apparatus has cooled, the bottles
are broken, and the fait in form of a cake is taken out,
which amounts to little lefs than one-third of the foot
which was employed. This manufa61ure is carried on
at Grand Cairo; and the French conful then refident
there, communicated an account of it to the Academy
of Sciences, in the year 1719. But it was not till
40 years after this period that it was manufactured in
Europe. The firfi: manufactory was eftabliflied in Ger¬
many in 1759 j others afterwards commenced in France,
and in different parts of Britain.
In the European manufactories it is prepared by dif¬
ferent proceffes. Sometimes the calcareous muriate is
precipitated by a carbonate of ammonia extracted from
animal matters. After the lime is depofited, the liquor is
evaporated, and the muriate of ammonia is fublimed.
Sometimes too it is prepared by forming a fulphate of am¬
monia, and by mixing ths fait with a muriate of foda, and
expofing the mixture to heat, a double decompofition
is effeCted, and the muriate of ammonia is fublimed.
It is alfo prepared by the direCt combination of muria¬
tic acid and ammonia.
3. Prepared in this way by fublimation, it is in the
form of a folid mafs, which has fome degree of elafti-
city. It yields to the preflure of the finger, may be
comprefled into a fmaller bulk, and is with difficulty
reduced to powder. The fpecific gravity is 1.42.
The tafte is pungent, acrid, and cooling. By folu-
tion in water and flow evaporation, it cryftallizes in
the form of long four-fided pyramids. The primitive
form of the cryftal is the regular oCiahedron ; and
that of the integrant particle, the regular tetrahedron.
Sometimes it cryftallizes in cubes, and fometimes the
prifms are very fmall, and grouped together, exhibit¬
ing a feathery appearance.
4. The muriate of ammonia is not altered by expo¬
sure to the air. It is foluble in three or four times its
weight of cold water. Great cold is produced during
Vol. V. Part II.
I S T R Y. 577
the folution ; and on this account it is employed with Ammonia,
fnow and ice in the production of artificial cold. Boil- ^■c-
ing water diffolves nearly its own weight of this v
hdt. _ 1x24
5. The muriate of ammonia is fufible and volatile. Of beat.
When it is thrown on red-hot coals, it is entirely dif-
fipated in white vapour. Expol'ed to a high tempera¬
ture, it is decompofed. II2-
6. This fait is readily decompofed by the fulphuric Of acids,
acid, which difengages the muriatic acid with violent
effervefcence. It is alfo decompofed by the nitric acid,
which oxygenates the muriatic acid. In this way a
nitro-muriatic acid is prepared, which is employed for
the folution of gold. Barytes, potafti, foda, and lime,
decompofe the muriate of ammonia, and difengage the
ammonia in the ftate of gas, merely by trituration j
but if heat be applied, the decompofition is more ra¬
pid and complete. it26
7. According to the analyfis of Mr Kirwan, theComP°fi-
component parts of the muriate of ammonia are, tl0n'
Acid,
Ammonia,
Water,
42.75
25.00
32.25
100.00 '
* Nicholfon t
‘Journal^
iil. 216.
1127
8. No fait is more generally employed than muriate Ufe-
of ammonia. In chemiftry it is ufed for the extrac¬
tion of ammonia, the carbonate of ammonia ; for the
produ&ion of cold, and as an inftrument of analyfis.
It is alfo employed in medicine 5 in the art of dyeing,
for the preparation of colours j in metallurgy, for the
indication and feparation of fome metallic fubftances.
It is ufed alfo for covering the furface of copper and
other veffels, to prevent oxydation in the procefs
of tinning j and for the fame purpofe in folder-
ing*
6. Hyperoxymuriate of Ammonia.
The compound of hyperoxymuriatic acid and am-prep^^
monia is formed by pouring carbonate of ammonia in-tion.
to a folution of any of the earthy hyperoxymuriates.
A double dtcompofition takes place, and a hyperoxy-
muriate of ammonia is formed. It is very foluble in
water and in alcohol. It is decompofed at a low tem-p ll29
perature, and gives out a quantity of gas together ^
with a fmell of hyperoxymuriatic acid. Such a fmell,
Mr Chenevix obferves, is doubtlefs owing to the great
quantity of oxygen contained in the acid, which is
more than wftiat is neceffary to combine with the hy¬
drogen contained in the alkali. Some part, therefore,’
is difengaged without decompolition. Mr Chenevix,
who formed this fait, could not fucceed in afcer'caining
the proportion 01 its comtituent parts
7. Fluate of Ammonia.
‘Tranf.
1802, p.
148.
XI30
1. This compound of fluoric acid and ammonia is Preparation
prepared by faturating the acid with the alkali. By and proper-
evaporation it cryftallizes in fmall needles or prifms, ties,
which have a pungent tafte analogous to that of ful¬
phate of ammonia.
2. When it is heated, this fait gives out ammonia,
and is fublimed in the ftate of an acidulous fluate.
This fait decompofes the nitrate and muriate of lime,
and the fulphate of magnefia.
4 D 8. Borate
57®
Ammonia,
&.C.
CHEMISTRY.
8. Borate of Ammonia.
Fourcroy
Connaifs.
Chim. iii.
P- 336-
II3I
Names and
hiftory.
1132
Prepara¬
tion.
II33
Properties.
”34
Action of
water.
1135
Of heat.
1136
Acids.
”37
Ufes.
1138
Prepara¬
tion.
”39
Properties.
1140
AfHon of
water.
1141
Of heat.
The compound of boracic and ammonia is little
known. It is formed by the direft union of the acid
with the alkali. It has fo little permanency, that the
folution being evaporated, the whole of the ammonia
is volatilized, while the boracic acid cryftadizes.
The bafe of every other fait decompofes it f.
9. Phofphate of Ammonia.
1 .This fait, the compound of phofphoric acid and am¬
monia, was long confounded with the phofphate of fo-
da, as it exifts with it in urine, under the names of
fiifible fait, native fait of urine, niicrocofmic fait. It
w’asfirft accurately diftinguifhed by Schloiier, De Chaul-
nes, and Rouelle, about the year 1770 ^ foon after by
Lavoifier, and more lately by \ auquelin.
2. At firft it was extracted from the fait of urine ;
and many precedes w'ere adopted to obtain it pure, and
feparate from the muriate and phofphate of fodn, with
which it is always accompanied. It is now prepared
artificially by dire&ly combining phofphoric acid with
ammonia j and by flow evaporation of the iolution to
a certain confidence cryflals are obtained on cooling.
3. The phofphate of ammonia cryflallizes in regular
four-fided prifms, terminated by four equal-fided pyra¬
mids, and fometimes in the form of fmall needles clofe-
ly interwoven vTith each other. It has a cooling, fa-
line, pungent tafle, and changes the fyrup of violets
to a green colour. Its fpecific gravity is 1.8051.
4. In a moid air, it is flightly deliquefeent, but
otherwife it is unchanged. It is foluble in four parts
of cold water, and dill more fo in boiling water.
5. Expofed to heat, it undergoes the w'atery fufion,
fwells up, and melts into a tranfparent glafs, which is
acid, part of the bafe being driven off. Hence it de¬
rived the name of fufible fait.
6. It is readily decompofed by charcoal, by the ful-
phuric, nitric, and muriatic acids, and by the two fixed
alkalies.
7. The phofphate of ammonia is employed as a flux
in effaying mineral fubdances with the blow-pipe. It
is greatly ufed alfo in the fabrication of coloured glaf-
fes and artificial precious dones.
10. Phofphite of Ammonia.
1. This is a compound of phofphorous acid and am¬
monia. It is prepared by the direft combination of
the acid with ammonia or the carbonate of ammonia,
and by flow evaporation it may be obtained in cry-
ffals.
2. It fometimes cryflallizes in long tranfparent
needles, and fometimes in four-fided prifms, terminat¬
ed by four-fided pyramids. It has a drong pungent
tafle. . ....
3. This fait is flightly deliquefeent in the air, is
foluble in twice its weight of cold water, and being
more foluble in boiling water, it crydallizes on cooling.
4. When it is heated on charcoal with the blow¬
pipe, it boils up, and lofes its water of crydallization.
When this has efcaped, it is furrounded wuth a fine
phofphoric light*, and as the fait begins to vitrify,
there are evolved bubbles of gas, which burn as they
come in contaft with the air, with a vivid flame, and
form with the atmofphere a ring of white vapour of
phofphoric acid. What remains is phofphoric acid in Ammonia,
the vitresus date. The fame effea may be produced . ,
by heating fix or feven grains of the lalt in a fmall
glafs globe to which a tube is adapted, and immerfed
under jars over mercury. The fait melts, fwells, and
gives out bubbles of phofphorated hydrogen gas, which
fpontaneoufly inflame as they come in contact with the
air, and exhibit the white coronet of vapour which is
the chara&eriflic property of the combudion of this
gas. During this decompofition, the bafe of the fait,
the ammonia, is alfo volatilized, and pure phofpnoric
acid remains behind. This fait is decompofed by
charcoal, the acids, and by potafh and foda.
5. The conflituent parts of this fait are the follow- compofi-
ing.
tion.
Phofphorous acid, 26
Ammonia, 5r
Water, 23
100
6. It has not hitherto been applied to any ufe.
11. Carbonate of Ammonia.
1. The compound of carbonic acid with ammonia Barnes,
has been diflinguithed by different names, as concrete
volatile alkali, aerated volatile alkali, and cretaceous fal
ammoniac. Its peculiar nature and properties were
not clearly underflood, till, by the difeovery of Dr
Black, it was demonflrated to be a compound fait.
This fait is obtained by a great many different procef-
fes. Formerly it wTas procured by diflilling animal
matters, and particularly horns, as the horns of tlm
hart, whence it derived the name of volatile fait of
hartlhorn. _ XI..
2. Carbonate of ammonia may be prepared by di- ptepara.
„re£lly combining carbonic acid and ammonia in the tion.
date of gas over mercury ; or it may be obtained by
mixing together twTo parts of chalk, and one part of
muriate of ammonia, well dried and reduced, to powT-
der, and expofing them to heat in a porcelain retort.
The gas, as it comes over, is collefted in a receiver,
which is to be cooled with cloths moiflened with wa¬
ter. This is the carbonate of ammonia, wdiich is .fub-
limed and attaches itfelf to the fides of the receiver.
In this procefs there is a double decompofition. The
carbonic acid of the lime combines with the ammonia,
and forms carbonate of ammonia, which is. driven off
by heat j and the muriatic acid of the muriate of am¬
monia combines with the lime, and forms muriate of
lime, which remains in the retort.. . IJ45
3. The carbonate of ammonia is crydallized 5 but propertie3.
the cryflals are fo irregular, that their form has not
been accurately afeertained. Bergman deferibes them
as octahedrons, whofe four angles are truncated ; while,
according to Rome de Lifle, they are compreffed four-
fided prifms, terminated by a two-fided fummit. The
tafle of this fait is flightly acrid, and the fmell is
perceptibly that of ammonia, though more feeble.
It converts vegetable blues to green. Its ipccific gra¬
vity is 0.966. . . t r , , 1146
4. When this fait is pure, it is not ienfibly changed A(aion o£
by expofure to the air. It is very loluble in water,water,
and, during its folution, produces cold. Two parts of
cold water diffolve more than one of the fait. Water,
at the temperature of about 120°, diffolves more than
its
C H E M
Ammonia, Its own weight, &c. When it is rapidly cooled, the
&tc* fait cryftallizes in the moft regular form which it af-
fumes. Boiling water cannot be employed for its fo-
lution, becaufe at this temperature the fait is driven
Of heat! off in ftate vaPour* When this fait is thrown
upon hot iron, it melts, boils, and is converted into
114S
Of acids.
H49
Compofi-
tion-
vapour.
5. It is decompefed by all the acids with ef-
fervefcence; and the effervefcence with this fait is
more violent than with the carbonates of the two fix¬
ed alkalies, becaufe the proportion of carbonic acid is
greater.
6. The conftituent parts of this fait, according to
Bergman, are,
Carbonic acid 45
Ammonia 43
Water - 12
100
But Mr ?Davy has found, that the proportion of
acid and water in this fait depends on the tempera¬
ture at which it is formed. It is greater when the
temperature Is low7, and diminifhes as the temperature
0 is increafed.
Ufes. 7* This fait is employed in medicine, and alfo in
the manufadture of muriate of ammonia, for which pur-
pofe it is produced by diftillation from animal matters.
The ufe of it, when it is mixed W'ith volatile oils, as
a perfume, or as a ftimulant in fmelling bottles, is well
known.
12. Arfeniate of Ammonia.
Prepara
tion.
1. This fait, the compound of arfenic acid and am¬
monia, is formed by combining the acid with the al¬
kali. When the folution is evaporated, it affords cry-
ftals of arfeniate of ammonia.
2. It cryftallizes in the form of rhomboidal prifmsj
or, with an excefs of acid, in the form of needles.
Properties, cryftals of the firft convert the fyrup of violets
into green, and thofe of the fecond are deliquefeent in
the air.
3. When this fait is gently heated, the ammonia is
difengaged, and the arfenic acid remains behind ; but
when the heat is violent and hidden, part of the alkali
and of the acid are decompofed, water is formed, azo¬
tic gas is difengaged, and the arfenic is fublimed in the
metallic ftate.
13. Arfenite of Ammonia.
1152
”S3
Action of
beat.
This is a compound of the white oxide of arfenic, or
arfenious acid, with ammonia 3 but nothing is knowm of
its properties.
IT54
Prepara¬
tion.
itss
Properties.
14. Tungftate of Ammonia.
1. This compound of tungftic acid and ammonia is
formed by diffolving the oxide of tungften in the folution
of ammonia or carbonate of ammonia 3 and by evapo¬
rating the folution, the fait is obtained in the form of
cry ft a!:..
2. It cryftallizes in fmall feales, which have fome
refemblance to boracic acid 3 or in fmall needles, which
are four-fided. This fait has a metallic tafte. It is
not deliquefeent in the air, but is foluble in water.
When it is expofed to heat, it is decompofed.
I S T R Y.
3. The component parts of this fait are,
Tungftic acid 18
Ammonia and water 22
100
15. Molybdate of Ammonia.
/6. Chromate of Ammonia,
» 17. Acetate of Ammonia.
1. This compound of acetic acid and ammonia bastion,
been long known by the name of fpiritus mindereri.
In this ftate it is combined with an excefs of acid. It
may be obtained, but with fome difficulty, on account
of its volatility, by flow evaporation. It then cryftal¬
lizes in the form of needles. Cryftals are alfo obtained Ir.w
by very flow7 fublimation of this fait. Properties.
2. The cryftals of acetate of ammonia are long, fien- * . ,
der, flat, and pointed, of a pearly white colour *. The
tafte is cooling, with a mixture of fweet. Expofed to menu,
air, it is deliquefeent, and is very foluble in water, p. 18S.
When it is heated to the temperature of 170°, it melts 3
and w7hen the temperature is raifed to 250°, it is fub¬
limed. By diftillation of the fait in folution, with a
ftrong heat, it is partly decompofed. The ammonia
is firft driven off, then the acid, and, towards the end
of the procefs, part of the neutral fait.
18. Oxalate of Ammonia.
iIS8
x. The compound of oxalic acid and ammonia may Prepara-
be prepared by dire611y combining the acid with the tion.
alkali. By evaporating the folution, the fait cryftal¬
lizes.
2. When the acid is faturated with the alkali, the
cryftals are in the form of four-fided prifms, terminated
by tw7o-fided fummits 3 one of wdiich is larger, and in¬
cludes three fides of the prifm. Thefe falts are folu¬
ble in water. 1.159
3. When this fait is expofed to heat, carbonate °f^,^lonof
ammonia is driven off, and nothing remains behind but
a little charcoal. From this it appears, that the acid
is decompofed, the carbone and oxygen combining to¬
gether to form carbonic acid, wdiich enters into combi¬
nation wdth ammonia. It is decompofed by the mi¬
neral acids. The oxalic acid combines wdth it, and
forms an acidulous oxalate of ammonia. The oxalates
of potafli and foda form compounds with this fait, which
are known by the name of triple falts.
4. This is one of the moft ufeful falts to be employed Ufes‘
as a reagent in detefting lime in liquid folutions, and
for afeertaining the nature and proportions of calcare¬
ous falts.
579
Ammonia,
&c.
1156
Prepara-
19. Tartrate of Ammonia.
The compound of tartaric acid and ammonia forms
a fait which very readily cryftallizes. This fait has
a cooling bitter tafte, is very foluble in water, and
eafily decompofed by heat. It is fubjeft alfo to fpon-
taneous decompofition. By the aftion of the ftronger
acids part of the bafe is feparated, and it is converted
into an acidulous tartrate of ammonia.
20. Citrate of Ammonia.
1. This fait, which is a compound of citric acid and
ammonia, is formed by the direft combination of the
4 D 2 acid
58°
C H E M I
Ammonia, acid and alkali, and it cryftallizes when the folution is
^'c' evaporated to the confiftence of a thick fymp.
2. The cryftals are in the form of an elongated prifm.
They are very foluble in water, and have a faline cool¬
ing tafte. This fait is decompofed by heat, the ammo¬
nia being driven off.
3. It is compofed of
Acid 62
Ammonia 38
100
* Fourcroy
Connaijs.
Chim. vii.
I9j-
1161
Prepara¬
tion.
116a
Properties.
1x63
Action of
.heat. '
1164
Of acids.
f Ann.de
Chim. XXVl.
P-3X-
21. Malate of Ammonia.
This fait, which is a compound of malic acid and
ammonia, is a very foluble and deliquefcent fait. Its
other properties are unknown.
22. Benzoate of Ammonia.
The compound of benzoic acid and ammonia forms
a very foluble fait, which readily cryftallizes, and the
cryftals arrange themfelves in an arborelcent or plu-
mofe form. This fait is volatile, and is decompofed by
all other acids *.
23. Succinate of Ammonia.
The compound of fuccinic acid and ammonia forms
« fait, which affords needle-fhaped cryftals that are
deliquefcent, and are fublimed by heat, without being
decompofed.
24. Saccolate of Ammonia.
Nothing farther is known of this fait, than that it
has an acid tafte, and is readily decompofed by heat.
25. Camphorate of Ammonia.
1. This fait, which is a compound of camphoric
acid and ammonia, is prepared by adding the acid to
a folution of carbonate of ammonia, and hot water,
till effervefcence ceafes. The evaporation muft be
conduced with a very gentle heat, on account of the
volatility of the ammonia.
2. It is difficult to obtain this fait cryftallized.
When the folution is too much evaporated, it affords
a cryftalline mafs, in which appear fmall needles ; but
if it be evaporated to drynefs there remains a folid
opaque mafs, which has a flightly bitter and pungent
ta^e* . r .....
3. This fait is flightly deliquefcent in the air ; it is
not very foluble in cold water, but may be diffolved
in three parts of boiling water. In .thefe falts, it
would appear that the acid refills the aftion of the wa¬
ter j for when there is an excefs of bafe, they become
more foluble.
4. Expofed to heat on red-hot coals, it fwells and
melts, and then rifes in vapour. With the blovy-pipe,
it gives a blue and red flame, and is entirely diffipat-
ed.
5. This fait is decompofed by the fulphuric, nitric,
and muriatic acids, and if the folution be fufficiently
concentrated, the camphoric acid is depofited. It is
alfo decompofed by potalh and foda, and more rapidly
with the affiftance of heat. This fait is completely fo¬
luble in alcohol f._
S T R Y.
Ammonia,
26. Suberate of Ammonia. &c.
This compound of fuberic acid with ammonia af¬
fords cryftals in the form of parallelepipeds. It has
a flight faltiffi tafte, leaving an impreflion of bitternefs.
It reddens vegetable blues, and is deliquelcent in the
air. It is very foluble in water. When it is thrown on
burning coals, it fwells up, and is deprived of its water
of cryftallization. It is entirely diffipated by the aftipn
of the blow-pipe. It is decompofed by the fulphuric,
nitric, muriatic, and oxalic acids, by the fixed alkalies,
and the aluminous and magnefian falts %. j A
27. Mellate of Ammonia. Chim.xxiil.
. ' ... 55*
This fait, which is a compound of mellitic acid and
ammonia, is formed by faturating the acid with the
alkali. By evaporation it affords tranfparent, fix-fided
cryftals. This fait when expofed to the air, becomes
opaque, and of a filvery white colour.
28. Ladlate of Ammonia.
This compound of la&ic acid and ammonia forms a
fait which cryftallizes. It is deliquelcent in the aiy,
and is decompofed by heat, great part of the ammonia
being driven off.
29. Prufliate of Ammonia.
The compound of pruffic acid and ammonia affords
a fait which has the odour of ammonia. When this
fait is expofed to heat, it is entirely diffipated.
30. Sebate of Ammonia.
31. Urate of Ammonia.
The compound of uric acid and ammonia, forms a
fait which is not very foluble in water, and in many
of its properties refembles the acid itfelf.
IV. Compounds of Ammonia with Inflammable Sub-
ftances.
1. Ammonia enters into combination with alcohol,
with the affiftance of a moderate heat j but the am¬
monia is feparated when the mixture is expofed to a
temperature below the boiling point of alcohol.
2. Ammonia readily mixes with ether 5 but the na¬
ture of the compound, or whether it be a chemical
combination, is not known.
3. Ammonia forms a compound with the fixed oils,
which is well known under the name of foaj> or /ini-
merit.
4. With the volatile oils it forms compounds, which
have fomewhat fimilar properties.
Chap. Xin. Of EARTHS.
j. The wrord earth is taken in different fignifica-
tions. Sometimes it fignifies the globe, and fometimes
it is ufed to denote the foil on the furface of the globe.
In chemiftry it is employed to fignify certain elementary
fubftances, of which a great proportion of the folid parts
of the globe is compofed ; and thefe fubftances are found
to poflefs many peculiar, and fome common properties.
2. The general properties of the earths are the fol-propert^
lowing.
a. They have neither tafte nor knell.
b. They
n66
Enumera'
tion..
C H E M
Lime, See. 1. They are incombuftible.
c. They are nearly infoluble in water.
d. They have a fpecific gravity which is under 5.
The number of the earths which are at prefent
known, is nine, and we (hall treat of them in the fol¬
lowing order.
1. Lime,
2. Barytes,
3. Strontites,
4. Magnefia,
5. Alumina,
6. Silica,
7. Yttria,
8. Glucina,
9. Zirconia.
Sect. I. Of Lime.
1 iffy
Early I. Lime has been known from the remoteft anti¬
known. quity The great abundance in which it is found in
nature, and the important ufes to which it may be
applied, led men to employ it for many purpofes from
the earlieft ages of the world. It was well known to
the ancients as mortar, and as a manure, and they were
not unacquainted with fome of its medical virtues.
But it was long before the nature and properties of
lime were fully knowm ; and particularly thofe changes
which quicklime undergoes when it is expofed to the
air, or limeftone to the a£Hon of heat. It was not till
Dr Black made his brilliant difeoveries, that the nature
of thefe changes was fully developed, and the fanciful
theories which had been propofed to account for them,
1168 were entirely rejefled.
Prepara- 2- Lime is feldom found perfe&ly pure in nature,
tion ot pure but it is univerfally diffufed, and exiils in fome places
lime. ;n t|ie greateft abundance, in combination with other
fubftances, and particularly with carbonic acid. To
obtain it pure, a quantity of chalk, or marble, or
limeftone, is expofed to a ftrong heat, by which means
the carbonic acid with which it is in combination is
driven off. When the limeftone, or marble, or chalk,
which has been employed, is fufficiently burnt or cal¬
cined, and removed from the fire, and water poured
upon it, it fwells up, and at laft falls down into a
powder. This pow^der is called quicklime. In this
procefs of flaking lime, as it is called, a great quanti¬
ty of water is quickly abforbed, and the water being
fixed in the lime in the folid ftate, gives out that calo¬
ric which is neceflary to retain it in the ftate of li-
1169 quidity, fo that a great quantity of heat is evolved.
Slaking. Part of the water, alfo, rifes in vapour, in confequence
of the great heat, before it is conlolidated with the
lime. The heat produced is fo great, that water may
be boiled, and combuftible bodies may be inflamed.
Accidents have happened to carriages and veflels load¬
ed with lime, to which water had been admitted. So
much heat was produced, that they have been fet fire
to, and burnt. Light is alfo emitted when lime is
flaked. This, it is faid, is feen when the procefs is
conducied in a dark place, and the quantity of lime
confiderable.
3. The purity of lime thus obtained, is in pro¬
portion to the purity of the fubftance which was cal¬
cined. The lime which is obtained by burning pure
I S T R Y. 581
white marble, or what is called calcareous fpary is to- Lime, See.
lerably pure. But there are other procefles by which
thofe fubftances with which it may happen to be mixed
may be feparated. If a quantity of chalk be waflied
in pure water, diffolved in ^diftilled acetic acid, and
afterwards precipitated by carbonate of ammonia, the
precipitate being walked and calcined, pure lime is the
product. The lime which is obtained from oyfter-
ftiells, may be rendered pure by the following procefs,
Firft walh the ftiells in different quantities of water, and
boil them, to feparate any mucilaginous fubftance. In¬
troduce them into a furnace, and calcine them to w’hite-
nefs. After the firft calcination, put them into a por¬
celain retort, and expofe it to a red heat. By this
procefs pure lime is obtained. To preferve it in this
ftate of purity, it muft be kept in clofe velfels. u^0
4. Pure lime is of a white colour, has a hot, fharp, Properties,
cauftic tafte, and deftroys the texture of animal fub¬
ftances, to wThich it is for fome time applied. It con¬
verts the fyrup of violets and other vegetable blues to
a green colour. The fpecific gravity of lime is 2.3. 1171
5. After the lime has been thus prepared and llak-A<ftion of
ed ; if more w^ater be added to dilute it, and reduce itwater*
to the confifteuce of thick cream, this is what was
formerly called milk or cream of lime. But if a greater
quantity of w?ater be added, and the folution be filter¬
ed, a tranfparent liquid is thus obtained, which is known
by the name of lime water. Four hundred and fifty
parts of water are required, it is faid, to diflblve one
of lime. This water is clear and limpid, has a (harp,
acrid tafte, and renders the fyrup of violets green.
When this water is evaporated, and the whole driven off,
the lime remains pure. If the folution of lime-water be
expofed to the air, the furface is foon covered with a pel¬
licle, which gradually acquires folidity and thicknefs.
This pellicle is owing to the attra&ion of the lime for
the carbonic acid of the atmofphere, forming a carbon¬
ate of lime, which being infoluble in water, is preci¬
pitated.^ . . 117&
6. Lime, according to Trommfdorf, cryftallizes. r»vftal-
This was firft difeovered by Scheele. The method by hz«*
which MrTrommfdorf obtained the cryftalsof lime is the
following. Boil any quantity at pleafure of muriate of
lime, with one-fourth or lefs of cauftic lime, and eva¬
porate the folution till a drop of it let fall on a cold
ftone aflume the confiftence of fyrup. It is then to be
filtered, and put into a clofe veffel, that the folution
may cool as flowly as poflible. Cryftals of lime are
thus obtained, which muft be walked in alcohol, to fe¬
parate any part of the muriate of lime which may ad- * Phil.
here. For the complete fuccefs of this experiment, Mag. xii.
fome pounds of the muriate of lime muft be employ- 53-
ed *. 1173
7. Lime undergoes no change by the aflion of light, A^on
and it remains unaltered when it is expofed to the^eat‘
greateft heat.
8. Lime is one of the moft important of the earthy
bodies. It is applied to a great many valuable pur¬
pofes, and fortunately it can be obtained in the great¬
eft: abundance. It is employed in medicine, both as an
internal.remedy, and an external application. As a
manure, it is of the moft extenfive utility 5 nor is it of
lefs importance, as it is employed for a cement in build¬
ing. When quicklime is mixed with fand and water,
and reduced to the form of a thick pafte, it is in the
ftate
582
G H E M I
Lime, &c. ftate of mortar. It is an objeft of the utmoft import-
' ance that the mortar which is employed as a cement in
building, fhould be durable. To attain this object, _a
good deal of attention has been paid by different phi-
lofophers, in afcertaining the proportions which feem to
anfwer beft, or the additions which may be made to
the ufual materials in the formation of good and dur¬
able mortar. The proportions which have been pro-
pofed by Dr Higgins are,
1x74
Mortar.
*175
Affinities.
Coarfe fand,
Fine fand,
Quicklime,
4 parts,
3
1
The lime (hould be recently flaked, and the quantity
of water {hould be juft fufficient to bring it to a proper
confiftency.
Dr Higgins found that burnt bones, if they did
not exceed one-fourth of the lime, added to the mor-
taf, improved its tenacity, and prevented it from crack¬
ing in drying. . .
'it has been propofed to add a certain proportion ot
unflaked lime to the mortar, with the view of giving
it greater lohdity. IVIortar acquires its hardnefs from
the lime abforbing carbonic acid, and returning to the
ftate of limeftone, and alfo from the combination of
part of the water with the lime. According to Guy¬
ton’s experiments the following proportions compofe a
good, durable mortar.
Fine fand _ 3 Parts>
Cement of well-baked bricks 3
Slaked lime 2
Unflaked 2
It is fometimes neceffary to ufe mortar as a cement
under water, but common mortar is unfit for this pur-
pofe. It has been found by experiment, that manga-
nefe added to mortar, gives it the property of confoli-
dating under water. To prepare a mortar for this pur¬
pose, Guyton recommends the following procefs. Mix
together 90 parts of limeftone, fix parts of black oxide
of manganefe, and 4 Parts °f blue clay in the ftate of
powder. Let the mixture be calcined, to drive off the
carbonic acid j then add 60 parts of fand and mix it
together with a fufficient quantity of water, to bring it
to the confiftency of mortar.
9. The order of the affinities of lime is the follow¬
ing:
Oxalic acid,
Sulphuric,
Tartaric,
Succinic
Phofphoric,
Sacladlic,
Nitric,
Muriatic,
Suberic,
Fluoric,
Arfenic,
* La&ic,
Citric,
Benzoic,
Sulphurous,
Acetic,
s T r Y.
Boracic,
Carbonic,
Pruflic.
I. Phofphuret of Lime.
Lime, Stc.
liyS
1. Lime combines with phofphorus, and forms a Prepara*
compound which is called phofphuret of lime. To tiom
prepare this compound, introduce into the bottom of
a glafs tube, doled at one end, one part of phofphor¬
us, and afterwards place a little above it four or five
times its-weight ot quicklime in powder. Expofe to a
heat that part ot the tube which contains the lime, fo
that it may become red-hot. In this ftate raife the
tube and draw it along the coals, till that part ot it
containing the phofphorus be alfo expofed to the heat.
The phofphorus is raifed in the ftate of vapour through
the lime, and combines with it, fo that the whole mafs
forms a compound of a brown colour. This is the
phofphuret of lime. Ji77
2. It has a deep brown colour, no fmell, and when Properties*,
it is expofed to the air it falls to pieces. It is infolu-
ble in water, but it decompofes that liquid at the mo¬
ment it comes in contad with it. An effervtfcence
takes place, and phofphorated hydrogen gas is emit¬
ted, w hich is fpontaneoufly inflamed when it comes to
the furface of the water. It is owing to this gas that
phofphuret of lime, when it is moiftened, gives out the
fetid fmell of garlic ; and as this gas is formed by the
decompofition of the w^ater, part of it combines with
the phofphuret of lime and forms a hydrogenated
phofphuret, fo that the phofphuret when it is taken
from the w^ater and dried, gives out flame, when con¬
centrated muriatic acid, which difcngages the phof¬
phorated hydrogen gas, is poured upon it.
II. Sulphuret of Lime.
1. This compound of fulphur and lime may be Prepara-
formed by expofing to heat in a crucible, fulphur and tl0n-
lime reduced to powder. They fufe {lightly, or rather
combine into an acrid, reddiflx mafs, which is the ful-
phui et of lime, formerly called calcareous liver of ful¬
phur. __ ”79
2. When it attra&s moifture from the air, or if a Hydrogen-
little water be thrown upon it, it changes colour, and
paffes to a greenilh yellow, emitting at the fame time an
extremely fetid odour, and forming fulphurated hydro¬
gen gas, becomes a hydrogenated fulphuret.
3. When fulphur and lime are combined together
by means of water, the refult is not a fimple fulphu¬
ret, but always a hydrogenated fulphuret, on account
of the wTater which is decompofed. This may be pre¬
pared, either by throwung water on quicklime, cover¬
ed with fulphur in powder ^ the heat which is emitted
by the flaking of the lime effetfting the combination :
or it may be prepared by heating in a matrafs, fulphur
and lime in powder with 10 times their weight of wa¬
ter, or by heating lime water on fulphur. By the two
firft proceffes, a liquid is obtained of a red, orange, or
yellow colour, of an extremely fetid odour,^ and a
pungent, acrid tafte. This hydrogenated fulphuret of
lime expofed to the air, is deprived of its colour, grad¬
ually decompofed, and the fulphur combining with the
oxygen of the air, is firft converted into fulphurous,
and afterwards into fulphuric acid. It is decompofed
bv
1
X,ime, &c.
1180
Hydro-ful-
phuret.
1181
Names.
n8i
Found na¬
tive.
1183
Properties.
1184
Adtion of
heat.
1185
Of acids.
1x86
Compofi-
tion.
by tbe acids, fulpbur is precipitated, and fulphurated
hydrogen gas is direngaged.
4. Lime combines readily with fulphurated hydro¬
gen. When fulphurated hydrogen gas is pafied into a
bottle of lime-water, the gas is abforbed and fixed by
combining with the lime, it renders it more folubie,
and forms the hydrofulphuret lime. This hydrofulphu-
ret, as Berthollet obferves, performs the part of an
acid, by faturating the lime, and gives it the property
of cryftallizing. This hydrofulphuret has no colour,
and expofed to the air, emits a ftrong fetid odour. It
is extremely folubie in water, and is decompofed by
the acids with effervefcence, while fulphurated hy¬
drogen gas is given out. Thus, lime enters into three
different combinations with fulphur, namely into the
fulphuret of lime, the hydrofulphuret, and the hydro¬
genated fulphuret.
III. Compounds of Lime with Acids.
I. Sulphate of Lime.
1. The compound of fulphuric acid and lime has
been known under a great variety of names, as felenite,
gypfum, plajler of Paris, alabajler, vitriol of lime. The
fulphate of lime is found in great abundance in naturej
and it is found fufficiently pure, fo that artificial pre¬
paration is not required.
2. When fulphate of lime is pure, - it is frequently
found cryftallized. The primitive form of its cryftals
is a quadrangular prifm, whofe bales are rhomboidal,
and the angles 113® and 67°. The integrant particle
has the fame form. The fpecific gravity is from 2.1679
to 2.3114. It is not changed by expofure to the air.
It is little folubie in water. Five hundred parts of cold
water, and 450 of boiling water, are required to diflblve
it. When it is expofed to heat, it lofes its water of
cryftallization, decrepitates, becomes very friable, and
falls down into a very white opaque powder. When
this powder is reduced to a palle with water, it ab-
forbs it very rapidly, and becomes in a very fliort time
folid. From this peculiar property, it is employed for
forming cajls, under the name of plafter of Paris.
When it is ftrongly heated for a long time, it becomes
phofphorefcent, and then melts*, and before the blow’-
pipeit gives an opaque, vitreous globule.
3. This fait becomes more folubie by the aftion of
fulphuric acid, without being converted into an aci¬
dulous fulphate of lime. The nitric and muriatic acids
increafe its folubility without decompofing it. It is part¬
ly decompofed by the phofphoric acid in the cold.
4. The component parts of fulphate of lime, accord¬
ing to Bergman, are,
, Acid 46
Lime 32
Water 22
CHEMISTR Y.
Anhydrous Sulphate of Lime.
583
Lime, &c.
IOO
After being dried in different temperatures, accord¬
ing to Mr Kirwan, the component parts are,
Dried in 270° In a red-beat. In a white heat.
55-84
Acid
Lime
Water
50 39
3 5 *2 3
14.38
j 00.00
38.81
5*35
100.00
59
4i
00
This is a variety of the fulphate of lime found native
in different places, which, as the name imports, con¬
tains no -water of cryftallization. It is found cryftal¬
lized. The primitive form of the cryftal is a rec¬
tangular prifm, having two of its bafes broader than
the other two. The fpecific gravity is 2.950. It has
a pearly luftre, confiderable hardnefs, phofphorefces
when it is heated, is tranfparent, and infoluble in wa¬
ter. The component parts are, according to the ana-
lyfis of Mr Chenevix,
Acid
Lime
44.88
J5*12
100.00
1187
2. Sulphite of Lime.
1. This fait may be prepared by paffing a current Prepara-
of fulphurous acid gas into a bottle of diftilled water,tion.
in which is fufpended pure carbonate of lime in pow¬
der. A brilk effervefcence takes place j the fulphite
as it forms, falls to the bottom in the ftate of powder j
and if the gas be continued to be added after the ef¬
fervefcence has ceafed, the fulphite of lime in the ftate
of powTder is completely re-diffolved $ the liquid be¬
comes warm ; and as it cools, it affords cryftals. 1x88
2. This fait is either in the ftate of white powder, or Properties,
in the form, of fix-fided prifms, terminated by long,
fix-fided pyramids. At firft it has no tafte, but when
it is kept in the mouth for fome time, it becomes ful-
phureous. It efflorefces flowly when expofed to the air,
and is converted into fulphate of lime on the furface.
It is lefs folubie in water than the fulphate of lime, re¬
quiring 800 parts of water to diffolve it. 1189
3. When it is expofed to heat, it is deprived of fome Adtion of
w*ater, becomes white, and is reduced to powder.heat*
A ftrong heat feparates fome fulphur, and it is then
converted into fulphate of lime.
4. The component parts of this fait are,
Sulphurous acid 48
Lime 47
Water 5
1190
CompoIL-
tion.
IOO
IOO
3. Nitrate of Lime.
1. This fait which is the compound of nitric acid HiftViy.
and lime has been long known under the names of cal¬
careous nitre, mother water of nitre, Baldwin’s phof-
phorus. It always accompanies nitre, and, as one of its
names imports, remains in the folution from which nitre
has been obtained. 119s
2. This fait may be prepared by diffolving carbo-Prepara-
nate of lime in nitric acid, evaporating to the con-tlon*
fiftence of fyrup, and allowing the folution to cool
flowly. It is thus obtained in the ftate of cryftals. 1193-'
3. The cryftals of nitrate of lime are in the form ofproperties,
fix-fided prifms, terminated by long pyramids. Some¬
times they are in the form of long ftriated needles,
grouped together, of a filvery whitenefs. The tafte is
acrid, hot, and bitter. The fpecific gravity is 1.6207.
4. This is one of the moft deliquefcent falls. Ex-AAion of
pofed to the air for a few hours, it is totally melted. water.
It
584 C H E M
Lime, See. It Is fometimes employed in chemiftry on account ot
this property of attracting moifture, to deprive gafes
of the vapour of water with which they may be com¬
bined. For this purpofe, the gafes are made to pafs
through tubes which contain dried nitrate of lime. It
is owing to a mixture of this fait, that nitre is fome¬
times deliquefeent in the air* T. he nitrate of lime is
extremely foluble in water. One part of cold water
diffolves four of this fait. Boiling water diffolves ftill
more.
5. When heated, this fait is very fufible. It melts
like oil, and after it becomes dry, it often acquires,
during calcination, the property of becoming lumi¬
nous in the dark. Hence the origin of one of its
names. More ftrongly heated, it is decompofed ;
gives out red vapours of nitrous gas, oxygen and azo¬
tic gafes, and there remains behind pure lime.
6. This fait is decompofed by the fulphuric acid,
partially by the phofphoric, and by potalh and foda.
By double affinity it is decompofed by the fulphates
of potafh, of foda, and ammonia. Sulphate of lime,
which is an infoluble fait, is always precipitated.
r r 7. By the analyfls of Bergman, the conftituent parts
^ion.^0 1 of nitrate of lime are the following.
Acid, 43
Lime, 32
Water, 25
too
By the analyfxs of Mr Kirwan, when it is well dried
in the air,
Acid, 57.44
Lime, 32.00
Water, 10.56
100.00
This fait has not been applied to any ufe. It js re¬
commended by Fourcroy as a fubditute for nitre in the
Of heat.
1196
@f acids.
1197
I S T R Y.
4. Expofed to heat, it becomes foft, melts, and Lime See,
fwells up, and then is deprived of its water of cryftal-
lization. At a very high temperature it is alfo de- o“OIf
prived of part of its acid. In this date, with an excefs jieat>
of lime, it acquires the property of fhining in the dark,
from which it has been called t/je phofphorus of Hom-
berg. _ # 120a
5. This fait is decompofed by the fulphuric acid, Of Acids,
by the nitric acid, which conveits it into the oxymu-
riatic, and partially by the phofphoric and fluoric
acids. 1303
6. According to the analyfis of Bergman, the con- Compofi-
ftituent parts of this fait are, tlon*
Muriatic acid, 31
Lime, 44
Water, 25
100
But according to Mr Kirwan, when it is dried in a
red heat, it is compofed of
Acid, 42
Lime, 50
Water, 8
100
7. This fait is only employed for chemical experi-
pients, and particularly for the produ&ion of artificial
cold, by mixing it with fnow or pounded ice. Of all
the falts employed for this purpofe, it feems to have
the greated effeft, in confequence of the rapid tranfi-
tion from the folid to the liquid date. To prepare the
fait for this purpofe, it is mod convenient to evapo¬
rate it to the confidence of a pretty thick fyrup; and
then by during it condantly as it cools, it is obtained
in a dry granulated date, wdiich fliould be reduced to
powder in the cold, and put up in bottles fecured with
ground doppers.
1204
Ufes.
* Fourcroy extraftion of nitric acid*.
Sonnaifs. 4. Nitrite of Lime.
Ghim. iii. _ .
P-133- When the nitrate of lime is expofed to heat, tul^ it
give out fome bubbles of oxygen gas, there remains
behind a calcareous nitrite, which converts vegetable
blues to green, and gives out a great quantity of red
vapour by the a&ion of acids. It feems to be in the
date of nitrite of lime, that this compound poffedes
f Ibid. the phofphorefcent property f.
5. Muriate of Lime.
1198
Names.
1199
Prepara¬
tion.
1200
Properties.
1. The compound of muriatic acid and lime has
been known by the names of calcareous marine fait,
fixed fal ammoniac, and Homberg's phofphorus. This
fait is frequently found in folution in fome mineral wa-
ters.
2. It is prepared by faturating muriatic acid with
carbonate of lime, and evaporating the folution to the
confidence of fyrup. It crydallizes on cooling.
3. The muriate of lime crydallizes in fix-fided
prifms, terminated by fix-fided pyramids. The tade
is acrid, bitter, and difagreeable. It is extremely
deliquefeent in the air. Cold water diffolves nearly
double its weight. Its foecific gravity is 1.76.
6. Hyperoxymuriate of Lime.
This fait, which is the compound of hyperoxymuri- Prepara-
atic acid and lime, is prepared by putting a quantity oftl0n''
pure white marble, reduced to powder, into one of the
bottles of Woulfe’s apparatus, half filled with water, and
by palling a current of oxymuriatic acid gas into the li¬
quid, till the effervefcence ceafes, and the powder has
nearly difappeared. It acquires a pungent flyptic
tade, with a reddilh colour. It exhales the odour of
oxymuriatic acid, and not of the hyperoxymuriatic
acid. When ammonia is added to this folution, it is^
decompofed, and there remains ordinary muriate of
lime, from which circumdance it feems doubtful whe¬
ther there is at all formed a hyperoxymuriate of lime.
According to Mr Chenevix, this fait is extremely de¬
liquefeent, melts at a low heat, in its v7ater of crjfial-
lization, and is very foluble in alcohol. I he compo-
nent parts of this fait are, tionlPO "
Acid, 55-2
Lime, 28.3
Water, 16.5
100.0
* Phil.
‘Tranf.
1802.
This
P. 147.
izo8
Hiftory.
izog
Prepara¬
tion.
mo
Properties.
tail
Adlion of
fee at.
C H E M
Lime, See. This fait has been fuccefsfully employed in the pro-
cefs of bleaching.
7. Fluate of Lime.
1. The compound of fluoric acid and lime has been
long known under the names of JIuor /par, cubic /par,
and phofpboric/par, from the figure of its cryftals, or
from fome of its properties. This fait exifts in great
abundance in nature, and in a ftate of confiderable pu¬
rity.
2. It may be artificially prepared, by combining
fluoric acid with lime in folution in water. The fait
is depofited in the form of powder in the bottom of
the veffel ; and when it is taken out, it is to be well
walked and dried.
3. When the fluate of lime is found native, it is ge¬
nerally cryftallized in the form of cubes, the angles of
which, and fometimes the edges, are truncated. The
primitive form of the cryftal is the regular o&ahedron.
The form of its integrant particle is the regular tetrahe¬
dron. It has frequently a confiderable degree of tranf-
parency, and exhibits a great variety of colours. The
fpecific gravity is 3.15. It has no tafte, is not altered
by expofure to the air, and it is infoluble in water.
4. When it is expofed to heat, it decrepitates and
becomes luminous in the dark j but when it has once
given out this light, it cannot be reftored, either by
expofing it to the fun’s rays, or by calcination with
charcoal or any other combuftible fubftance. From
this circumftance it appears, that this phofphorefcent
property is owing to fome volatile principle which has
been a conllituent part of the fait. The artificial
fluate of lime alfo poflefles the fame property, and even,
according to Scheele, in a higher degree. When it is
ftrongly heated, it melts into a tranfparent glafs.
5. This fait is decompofed by the fulphuric, ni¬
tric and muriatic acids, by the carbonates of potaih
and foda, and by moft of the phofphates. It is by de-
compofing it by means of the fulphuric acid, that the
fluoric acid is obtained.
6. The fluate of lime is much employed in fmall
pieces of fculpture, and for ornamental purpofes in the
formation of cups, vafes, and pyramids. It is employ¬
ed alfo as a flux for mineral fubftances.
8. Borate of Lime.
This fait, which is a compound of boracic acid and
lime, is prepared by pouring a folution of boracic acid
into lime water, or by decompofing the foluble alka¬
line borates by means of lime water. A precipitate is
thus formed, of a fait nearly infoluble, which is infi-
pid, and in the form of a white powder. Little is
known of the properties of this fait.
9. Phofphate of Lime.
1214 I. The compound of phofphoric acid and lime,
Hiftory and known under the name of calcareous phofphoric fah,
prepara- js one cf t]ie niofl: interefting difeoveries of modern
chemiftry. This was made by Scheele and Gahn in
1774, when they proved that it formed the bafis of
bones. To obtain this fait in a ftate of purity, a quan¬
tity of bones is calcined to whitenefs, reduced to pow¬
der, and rvell w’aftied with water to feparate the carbo¬
nate of foda and other foluble falts which are general¬
ly combined with it. The phofphate of lime is thus
Yol. V. Part II.
585
1212.
Of acids.
IZI3
Ufes.
I S T R Y.
procured in the form of an infipid white powder. In Lime, &c.
this ftate it is generally mixed with a little carbonate 
of lime, which may be feparated by diluted acetic acid,
and afterwards walking it with water. 1ZJS
2. By this proceis the phoiphate of lime is procured Properties,
in a ftate of purity from the foiid matter of bones. It
has no tafte, and does not change the colour of vege-u
table blues. When it is prepared artificially, it is in
the form of white powder, but as it exifts in nature, it
is found regularly cryftallized. This is known to mi-
neralogifts under the name of apatite, of which there
are feveral varieties. The primitive form of its erv-
ftal is the regular fix-fided prilm ; the primitive form
of the integrant molecule is a three-fided prifm, whofe
bafes are equilateral triangles. It remains unaltered
by expofure to the air, and it is foluble in water. 12Ig
3. When this fait is expofed to heat, it fcarcely un-Aftionof
dergoes any change ; but when it is expofed to theheat-
ftrong heat of a glafshoufe furnace, it is converted in¬
to a lemitranfparent porcelain. iixi
4. The phofphate of lime is decompofed by the ful- Of acids,
phuric, nitric, muriatic, and other acids $ but this de-
compofition is only partial. Part of the lime only is
abftracfted, and the fait is converted into an acidulous
phofphate of lime. iaig
5. The component parts of phofphate of lime, ac-Compofi-
cording to Fourcroy and Vauquelin, are, tion.
Acid,
Lime,
41
59
100
6. The phofphate of lime is of great importance in pfeTs2I?
chemiftry, for the purpofe of extrading phofphoric
acid, to be decompofed to obtain phofphorus. It is
alfo employed for making cupels, for polifliing metals
and precious ftones, and for removing fpots of greafe
from linen, paper, and filk. It is ufed in medicine as
a remedy for rickets, to corred the fuppofed effeds of
acids in foftening the bones.
Superphofphate of Lime.
1210
1221
ra-
1. This fait, with an excefs of acid, wTas dtfeovered
by Fourcroy and Vauquelin in 1795. Scheele had re- " °r>’
marked, that the phofphate of lime was diffolved by
an acid in human urine, but he had not afeertained
that this combination between the phofphoric acid and
the phofphate of lime, conftituted a permanent fait.
2. It may be obtained artificially by the partial de Pl.ep^
compofition of the phofphate of lime by means of any tion.
acid, or by diffblving this fait in phofphoric acid. This
laft procefs, Fourcroy obferves, is the moft certain ;
and when the phofphoric acid has diffolved as much as
it can take up of the phofphate of lime, the fait is in
the ftate of acidulous phofphate, or fuperphofphate. I222
3. This fait cryftallizes in fmall filky threads, or in Properties,
brilliant plates of a pearly luftre, which are attached
to each other, and feem to have the confiftence of ho¬
ney or glue. It has a ftrong acid tafte. Expofed to
the air, it is {lightly deliquefeent. It is foluble in water,
and the folution produces cold. It is more foluble in
boiling water, and cryftallizes by cooling.
4. When this fait is expofed to heat, it firft melts, Adbon of
and then fwells up and dries. If the temperature be heat,
increafed, it undergoes the igneous fufion, and is con-
4 verte^
1224
Compoii-
tion.
# Pourcrty
Cvnnaifs'
Cbim. iii.
P- 247'
1225
Prepara¬
tion.
1226
properties.
1227
Adlion of
heat.
1228
Of acids.
1229
Compofi-
tion.
5230
Hames.
1231
Prepara¬
tion.
C H E M I
verted into a tranfparent glafs. The phofphoric acid
in this fait is more readily decompofed by charcoal
than in the neutral phofphate of lime. It is not de¬
compofed by any of the acids, excepting the oxalic.
The proportions of its conllituent parts are the fol¬
lowing.
Acid, 54
Lime, 46
100 *.
10. Phofphite of Lime.
1. This fait, compofed of phofphorous acid and
lime, is formed by the diredd combination of the acid
with the earth, and when they are faturated, it falls
to the bottom in the form of white powder. This
powder is re-diffolved with an excefs of acid, and in
this date of acidulous phofphite of lime, cryftallizes by
evaporating the folution.
2. When thus obtained, it is in the form of a white
powder, if it is juft neutralized ; but with an excefs of
acid, it forms fmall prifms or needles. This fait has
no tafte •, it is not changed by expofure to the air j
and it is infoluble in water.
3. When it is expofed to heat, it gives out a phof¬
phoric light, yields a fmall quantity of phofphorus,
and is converted into a phofphate. By the a£Hon of
the blow-pipe it melts into a tranfparent globule.
4. The neutral phofphite of lime is foluble in acids,
without being decompofed. The proportions of its
conftituent parts are,
S T R Y.
4. The carbonate of lime is readily decompofed by
all the acids with effervefcence,vowing to the difen-
gagement of the carbonic acid in the date of gas. of acids.
5. The component parts of carbonate of lime, as ^35
they have been afcertained by the analyfes of Bergman Compoli-
and Kirwan, are the following.
Phofphorous acid,
Lime,
Water,
34
51
15
100
1*3*
Fropeiues.
rJ*33
Aftion of
heat.
Bergman.
Acid, 34
Lime, 55
Water, 11
Kirwan.
45
55
00
100
100
12. Arfeniate of Lime.
1236
II. Carbonate of Lime.
1. This fait exifts in great abundance in nature j
and it is known by a great variety of names, as limejfcme,
marble, cha/h. It may be prepared artificially, by di-
re&Iy combining carbonic acid with lime ; but in this
procefs the proportions of the acid and earth muft be
accurately adjufted ; for, if there is too little acid, the
fjrft precipitate which is formed is re-diffolved in the
■water, and feems to form carbonate with excefs of
lime. If there be too much acid,, the carbonate firfl:
precipitated is alfot re-diffolved, and difappears in this
excefs of carbonic acid.
2. The carbonate of lime is perfe&ly taffelefs. The
fpecific gravity is 2.7. It is frequently found cryftal-
lized, and exhibits a great variety of forms. When it
is tranfparent and in the rhombcidal form, it has the
property of double refra£tion. The primitive form of
its cryftals is an obtufe rhomboid, whofe angles are
about 101-^-0 and 784-0. The. integrant molecule has
the fame form.
3. When it is expofed to the air it undergoes no
change. It is infoluble in water.
4. Expofed to a ftrong heat, it decrepitates, and is
deprived of its water of cryftallization. It becomes
white, opaque, and friable. If the beat be increafed
and continued, the whole of the carbonic acid is drl.
yen off in the ftate of gas.
This fait, which is a compound of arfenic acid and Prepara-
lime, is prepared by dropping the acid into lime water. tlon‘
A precipitate is formed, which is foluble, either with * Fourcrty
an excefs of the bafe, or the acid. Or it may be form- v.*
ed by diffolving carbonate of lime in arlenic acid.p
The acidulous arfeniate of lime, when it is evaporat- 1237
ed, affords fmall cryftals. When this fait is heated, it Adhon of
melts, but is not decompofed *. lieat‘
12. Tungftate of Lime.
° . . . . I2o8
The compound formed by tungftic acid and lime, is Found na-
found native. It is from the mineral called tungften, tive.
that the metallic fubftance is obtained which bears this 1239
name. When the folution of tungftic acid is added Prepata,
to lime water, a precipitate of tungftate of lime istl0U-
formed, fimilar to the native compound tungften.
This mineral is found cryftallized. The primitive
form of the cryftal is the odlahedron, which is com¬
pofed of turn four-fided pyramids, applied bale to bafe.
It is of a yellowifti colour, with fome degree of trani-
fparency and confiderable hardnefs. It is infolvtble
in water, and is fcarcely altered by the aaion of heat. JUo
The fpecific gravity is about fix. The component parts coropofi-
of this fait are, tlon*
Tungftic acid
Lime
70
3°
100
14. Molybdate of Lime.
15. Acetate of Lime.
1242
1. The compound of acetic acid and lime is formed Prepara-
by diffolving the carbonate of lime in the acid, till rttion.
is faturated. By evaporating the folution till a pelliclfe
forms on the furface, it cryftallizes on copling, I24a
2. The cryftals of acetate of lime are in the form of pr0pertie&>
fmall prifms, with a firming filky luftre. The tafte is
bitter and four.. It is not changed by expofure to the
air, but is foluble in water. * The fpecific gravity is
1.005. , . . , rj 1243
3. When it is expofed to heat, it is decompoied, Aaion of
partly by the feparation of the acid, and pai tly by itsfieat.
decompofition. The component parts of this fait, ac_^ornp^
cording to X)r Higgins, are, tion.
Acetic acid and wrater 64.3
Lime 35-7
100.of
f Experi-
j(J, 47.
Ume,
TS45
Prepara¬
tion.
1246
Prepara¬
tion.
1247
Compoli-
tion.
■* Fourcroy
Tii. p. 207.
1248
Prepara¬
tion.
1249
Exifts in
plants.
1250
Properties.
C H E M
16. Oxalate of Lime.
The oxalic acid faturated with lime, forms an in-
foluble fait, which may be formed by dropping oxalic
acid into any of the acid folutions of lime. The oxalate
of lime thus formed, is a white powder, which converts
the fyrup of violets to a green. This fait cannot be de-
compofed by any other acid, the affinity of oxalic acid
for lime is fo ftrong. It is on this account that oxalic
acid is employed as a tell for lime, whether it is in a
Hate of combination, or uncombined. This fait may
be decompofed by expofmg it to heat. The acid itfelf
is driven off, and undergoes decompofition.
The component parts of this fait, according to Berg¬
man, are,
Acid 48
Lime 46
Water 6
ICO
17. Tartrate of Lime.
The compound of tartaric acid and lime may be form¬
ed, by diffolving lime in the acid ; or by adding a
folution of lime in powder to a folution of tartar in
boiling water, till it ceafes to effervefce, and to redden
vegetable blues. The fait precipitates in the form of
a white powder, which is infoluble, excepting with an
excefs of acid. This fait is decompofed by the fulphu-
jric, nitric, and muriatic acids.
18. Citrate of Lime.
This fait, which is a compound of citric acid and
Kme, may be formed by the direft combination of the
acid and the earth. Small cryftals are formed, which
are precipitated, and are fcarcely foluble in water, ex¬
cepting with an excefs of acid, and from this folution
it may be obtained cryftallized. The component parts
of this fait are,
Citric acid 62.66
Lime 37 34
100.00 *
ip. Malate of Lime.
1. The compound of malic acid and lime may be
formed by combining the acid with the earth, and
neutralizing them. Small irregular cryftals are thus
obtained, which are fcarcely foluble in boiling water,
but become very foluble with an excefs of acid. In
this ftate it is the fupermalate of lime. This fait is found
ready formed in forne vegetables, as in houfe-leek and
fimilar fucculent plants.
2. This acidulous malate of lime has an acid tafte.
When it is evaporated, it forms a folid, ffiining fub-
ftance, analogous to varnilh. It is decompofed by the
fulphuric and oxalic acids, and alfo by the alkalies.
Lime water added to a lolution of this fait, combines
with excefs of acid, and precipitates the malate of
lime.
20. Gallate of Lime.
The gallic acid combined with lime, forms a yel-
I S T R Y. 587
lowiffi coloured, infoluble fait, which, with an excefs L-me, &c.
of bafe, becomes foluble. <
21. Benzoate of Lime.
The compound of benzoic acid and lime, forms a
fait which is very foluble in water. This fait cryftal-
lizes in an arborefcent form on the fides of the vcffel
which contains the folution. It is decompofed by the
fulphuric, nitric, and muriatic acids. It exifts in great
abundance in the urine of graminivorous quadrupeds.
22. Succinate of Lime.
The compound of fuccinic acid and lime forms falts
which are not very foluble in water, and are not alter¬
ed by expofure to the air.
23. Saccolate of Lime.
Saclactic acid and lime form an infoluble fait.
24. Camphorate of Lime.
1. This fait, which is a compound of camphoric Prepara-
acid and lime, is formed by adding lime water to cryf-bon.
tallized camphoric acid. The folution is then to be
boiled, filtered, and evaporated to three-fourths of its
quantity. As it cools, the fait is depofited.
2. The camphorate of lime has no regular fliape, un-Properties,
lefs the evaporation has been properly managed, when
it is found in the form of plates lying on each other.
It is of a white colour, and has a ftightly bitter tafte.
3. It effiorefces in the air, and falls down into A&ion of
powder. It is fcarcely foluble in cold, and requires water and
about 200 parts of boiling water for its folution.heat*
When it is expofed to heat, if it be moderate, it melts
and fwells, but if thrown on red-hot coals, or heated
in clofe veffels, the acid is decompofed and lublimed.,
and the lime remains pure.
4. It is decompofed by the fulphuric, nitric, and mu¬
riatic acids. With the fulphuric acid there is formed
an infoluble precipitate. The nitric and muriatic acids
precipitate the camphoric acid. 7'his fait is alfo de¬
compofed by the carbonate of potalh, and the phof-
phate of foda.
5. The component parts of this fait are,
Camphoric acid 50
Lime 43
Water 7
100 *.
* Afin. it
Cbitn.
25. Suberate of Lime. ‘'
This fait, which is a compound of fuberic acid and Properties,
lime, does not cryftallize, is perfeftly white, has a
flight faline tafte, and does not redden the tinfture of
turnfole. It is fcarcely foluble in cold water. Boil¬
ing water diffolves it more abundantly, but as it cools, 1255
a part of it is precipitated. When it is placed upon Aiflion of
burning coals, it fwells up, the acid is decompofed,, ^eat'
and the lime remains in the ftate of powder. This
fait is decompofed by the fulphuric, nitric, and muri¬
atic acids, by potalh and foda, and their carbonates,
and by the phofphate and borate of loda f. f Mid. xxiib
26. Mellate of Lime.
' P- 54-
The mellitic acid dropt into lime-water, forms a
precipitate which is re-diffolved by adding nitric acid.
4 £ 2 Oi
588
Barytes,
See.
1256
lliftory.
Jidin,
‘Tranf. iv.
Z6-
f Ann. de
Chlm. xxi.
1I3*
1257
Prepara¬
tion.
C H E M
Or when the mellitic acid is mixed with a folution of
fulphate of lime, a precipitate is formed of fmall, grit¬
ty cryftals, which do not affe£l the tranfparency of the
wTater.
27. Laffate of Lime.
The compound of la£lic acid and lime forms a deli-
quefeent fait, which is foluble in alcohol.
28. Pruffiate of Lime.
The compound of pruflic acid and lime is formed
by diflolving the lime in the acid. I he folution is
then to be filtered, and the lime which has not com¬
bined with the acid is to be feparated by adding car¬
bonic acid in wuter, in the proportion neceflary to pre¬
cipitate the lime from the fame bulk of lime-water.
The folution, after a fecond filtration, muft be pre-
ferved in clofe veffels. By diftillation the prufiic acid
is driven off, and the pure lime remains behind. This
fait is decompqfed by all the other acids, and alfo by
the alkalies.
29. Sebate of Lime.
When febacic acid is dropped into lime-wTater,
the tranfparency of the wrater is not difiurbed, lb
that the compound of this acid with lime is foluble in
water,
IV. Compounds of Lime with Inflammable Subftances.
Lime does not enter into combination with alcohol
or ether ; but, it forms compounds with the fixed oils
which are known by the name of foaps. Lime com¬
bines alfo in fmall quantity with the volatile oils,
forming a fimilar compound.
Sect. II. Of Barytes and its Combinations.
For the knowdedge of this earth wre are indebted to
modern chemiftry. It was difeovered by Scheele in
1774 j and its properties w'ere inveftigated by him, and
in the following year by Gahn, who analyzed a mine¬
ral which had been diftinguilhed by the name of pon¬
derous fpar, on account of its weight, and found that
it was compofed of fulphuric acid and the new earth.
It received the name of terraponderofa from Bergman,
who alfo examined its properties, and confirmed the
experiments of Scheele and Gahn. Mr Kirwan gave
it the name of barytes, from the Greek word
which fignifies heavy. Its properties were farther in¬
veftigated by Dr Hope, in 1793 *, and by Pelletier,
Fourcroy, and Vauquelin in 1797 f.
2. This earth may be obtained in a ftate of pu¬
rity by the following procefs : A quantity of ful¬
phate of barytes, a mineral found in confiderable
abundance in nature, is firft reduced to a fine pow^der.
Mix it with ^ of its wreight of charcoal powder, and
expofe the mixture in a crucible to a ftrong heat, for
feveral hours. The fulphuric acid, by this procefs, is
decompofed, by being deprived of its oxygen, which
combines with the carbone of the charcoal, and forms
carbonic acid, which is driven off. The fulphur re¬
mains in combination with the earth, forming a ful-
phuret of barytes. This fulphuret is to be diflolved
I S T R Y.
in water, and nitric acid poured into the folution. The Barytes,
nitric acid combines with the barytes, and forms nitrate ^LC’
of barytes, while the lulphur is precipitated. The fo- v
lution is to be filtered, and flowly evaporated till it
cryftallize. The cryftals thus formed are then put in¬
to a crucible, and expofed to a ftrong heat. The ni¬
tric acid is decompofed, and driven off, and the earth
remains behind in a ftate of purity.
Dr Hope has recommended another procefs, which
is more economical. By this procefs the fulphate of
barytes is decompofed as in the former. The fulphu¬
ret which is obtained, is thrown into water, that all
foluble matters may be diffolved. To the folution, af¬
ter filtration, a folution of carbonate of foda is to be
added. A precipitate takes place in the form of a
white powder. This powrder is to be walked with w’a-
ter, made up into balls with charcoal, and expofed to a
ftrong heat in a crucible. The balls are afterwards
to be thrown into boiling w^ater, when part of the
barytes is found diffolved, and, as the w7ater cools, it
cryftallizes. 125?
3. Barytes, as it is obtained by decompofing the Properties,
nitrate in the firft procefs, is in the form of final], gray,
porous maffes, which are eafily reduced to powder. It
has a hot, burning tafte ; and, when introduced into
the ftomach, is a deadly poifon. Its fpecific gravity
is 4.00. It deftroys the texture of all animal fubftan-
ces. It converts vegetable blues to a green colour.
In many of its properties it is perfedlly analogous to
the fixed alkalies. I2^
4. When it is expofed to the air, efpecially if the AdHon of
atmofphere be loaded with moifture, it fwells up in a water.
fewT minutes, becomes hot, and at laft falls into a white
powder. It is then deprived of part of its acrimony, and
is increafed in weight 0.22. This is owing to the ab-
forption of w^ater from the atmofphere. If a fmall
quantity of water be thrown upon barytes, it boils up,
is ftrongly heated, is enlarged in volume, and gives
out a great quantity of heat. After being flaked in
this manner, it is diluted with water, the earth cryftal¬
lizes, and affumes the appearance of needle-formed cry¬
ftals, which, at the end of fome time, if expofed to the
air, fpontaneoufly fall to powder. With a greater quan¬
tity of water the barytes is completely diffolved. Cold
water takes up about of its weight. This folution
changes the fyrup of violets to green, and at laft de¬
ftroys the colour. When this liquid is expofed to the
air, a thick pellicle is formed on the furface, wLich is
owing to the abforption of carbonic acid from the at¬
mofphere. Boiling water diffolves 4 its weight of
pure barytes. The folution affords cryftals as it cools.
They are in the form of long, four-fided prifms, tranf-
parent and white, which efflorefee in the air 5 but the
form of the cryftals varies according to the rapidity of
the evaporation and cryftallization. I2g0
5. Light has no aftion on barytes. Heated on char- Of heat,
coal with the blow7-pipe, it melts into an opaque, gray
globule, which foon penetrates the charcoal. Expofed
to heat in a crucible, it melts, and attaches itfelf to the
fides of the veffel, to which it adheres ftrongly, form-
ihg a kind of greenilh covering. Lefs ftrongly heated,
it hardens, and internally affumes a bluifti green fliade.
There is no aftion between barytes and oxygen, azote,
hydrogen, or carbone.
1
I. Phofphuret
Earvtes,
&c.
1261
Prepara¬
tion.
1262
Properties.
* Fourcroy
Connaifs.
Chint. ii.
p. 191.
1263
Prepara¬
tion.
1264
Properties.
1*65
Hydroge¬
nated i'ul-
phuret.
ra66
Three com¬
pounds.
C H E M
I. Phafphuret of Barytes.
1. Barytes enters into combination with phofphorus,
forming the compound called phofphuret of barytes.
This is prepared by introducing a mixture of barytes
and phofphorus into a glafs tube cloied at one end, and
expofing the mixture to the heat of burning coals.
The two fubftances rapidly combine together.
2. The phofphuret of barytes, thus obtained, is of a
dark or Ihining brown colour, having a metallic ap¬
pearance, very fufible, and exhaling, when it is moif-
tened, a ftrong fetid odour : in the dark it is lumi¬
nous. When it is thrown into water, it is decompo-
fed, giving out phofphorated hydrogen gas, and is gra¬
dually converted, by the aftion of the air and the wa¬
ter, into phofphate of barytes *.
II. Sulphuret of Barytes.
A fimilar combination alfo takes place between ba¬
rytes and f dphur. This combination may be formed
by introducing barytes and fulphur well mixed toge¬
ther, into a crucible, and expofing them to a red heat.
At that temperature the mixture melts, and the com¬
pound which is formed is the fulphuret of barytes.
This fubftance is very foluble in water, which it in-
flantly decompofes; and, when it is faturated with the
fulphurated hydrogen w'hich is formed, it is converted
into a hydrogenated fulphuret of barytes, which depofits
by cooling, cryftals of different forms, fometimes in that
of fmall needles, fometimes in that of large fix-fided
prifms, fometimes in the form of oftahedrons, and of¬
ten in that of fmall, brilliant, hexagonal plates, which
are cryftals of fulphurated hydrogen and barytes, de¬
nominated by Berthollet, hydrofulphuret of barytes.
When the fulphuret of barytes is diflblved in water,
it inftantly exhales the fetid odour of fulphurated hy¬
drogen gas. The liquid which has depofited cryftals
of hydrofulphuret of barytes, retains a hydrogenated
fulphuret in folution. When it is expofed to the air,
this folution becomes of an orange yellow. Cryftals
of hydrofulphuret of barytes, with fpots or yellowifh
plates, are often obferved in the midft of the white
malfes.
3. The fulphuret of barytes is moft remarkable for
the great rapidity with which it decompofes water, and
the great quantity of the fulphurated hydrogen with
which it combines, forming the hydrofulphuret of ba¬
rytes ; which latter is ilowly, and with difficulty,decom-
pofed by the air, and the great proportion of fulphu¬
rated hydrogen gas which is difengaged by the action
of acids, without any precipitation of fulphur.
4. Thus, there are three different combinations of
fulphur with barytes. In the firft, the fulphur is di-
re£Uy combined with the barytes, as when they are ex¬
pofed to heat in the ftate of drynefs, which is the fimple
fulphuret of barytes. In the other, the fulphur com¬
bined with the hydrogen, is in the ftate of hydroful¬
phuret of barytes. This compound is prepared by paf-
fmg fulphurated hydropen gas into water holding ba¬
rytes in folution, which, as it combines with the gas,
becomes more foluble, and is condenfed and abforbed by
the water. The diftindftive charafter between the latter
combination and that of the fulphuret of barytes is,
that the firft, by the a&ion of acids, only gives out
I S T R Y.
fulphurated hydrogen gas, without any depofition of
fulphur ; and the fecond, expofed to heat, is deprived
of its fulphur, which is fublimed,. without affording
fulphurated hydrogen gas. Between thefe two ftates,
there is an intermediate combination, in which the ful¬
phuret of barytes holds in folution more or lefs ful¬
phurated hydrogen •, fo that, by the aftion of acids, it
affords fulphurated hydrogen gas, with a depofition of
fulphur at the fame time. To this intermediate com¬
pound, Berthollet has given the name of hydrogenated
fulphuret of barytes *.
III. Compounds of Barytes with the Acids.
589
Barytes,
Stc.
* Fourcroy
Connaifs.
Chim. ii.
p. 191.
Barytes enters into combination with the acids, and
forms with them compounds, which are diftinguilhed 1267
by the name of falls. The order of affinities of ba- Aftinities>
rytes for the acids, according to Bergman, is the fol¬
lowing.
Sulphuric acid,
Oxalic,
Succinic,
Fluoric,
Phofphoric,
Sacla&ic,
Nitric,
Muriatic,
Suberic,
Citric,
Tartaric,
Arfenic,
Laddie,
Benzoic,
Acetic,
Boracic,
Sulphurous,
Carbonic,
Pruffic.
1. Sulphate of Barytes.
1268
1. This fait, which is a compound of fulphuric acid Found naw
and barytes, was formerly diftinguiffied by the name of “ve*
heavy fpar, phofphoric fpar, or Bolognianfone. It ex-
ifts in great abundance in nature, particularly accom¬
panying metallic veins; from which circumftance, pro¬
bably, and from its great weight, it was fuppofed to
contain a metallic fubftance. It is rarely formed ar¬
tificially, as that found in nature is fufficiently pure. 1269
2. The fulphate of barytes is the heavieft of all the Properties,
falls, the fpecific gravity being 4.4. It has neither
tafte nor fmell. Sometimes it is found cryftallized,
and fometimes compadl. There is a confiderable va¬
riety among the forms of its cryftals. The primitive
form of fulphate of barytes is a rhomboid, with right
angles at the bafes, whofe angles are ioi4-° and 784-0.
The integrant molecule is the fame. 1270
3. This fait remains unchanged in the air, and it is Adhon of
infoluble in w?ater. When it is fuddenly heated, it-'eat'
decrepitates. By the adlion of a ftrong heat, it melts
with difficulty ; and before the blow-pipe it fufes, and
is converted into a white opaque globule. It is de-
compofed at a red heat by hydrogen and charcoal, and
is converted into a fulphuret which is phofphoric.
This was formerly called, from an accident, Bolognian
phofphorus.
S9°
Barvtes,
&c.
T271
Compofi-
tiou. '
C H E M I
phofphcrus. A piece of tlie fulphate of barytes was
found in the neighbourhood of Bologna, by a fhoe-
maker of that city, who fufpecling that it contained
filver, put it into the fire to feparate the metal. He
found no filver, but he obferved that by heating it ac¬
quired the property of fhining in the dark, and thence
it obtained the name of Bologniau ftone or pholpho-
lus.
This fait is decompofed-by the carbonates of potafli
and foda, .either by expofing them to s. ftrong heat in
a crucible, or by boiling them together in folution.
According to the different analyfes which have been
made to afcertain the conftituents of this fait, it ap¬
pears that there is a confiderable difference between
the natural and artificial fulphate of barytes, as in the
following table.
# Fourtrty
Ctnnatfs.
Chim. iii.
p. 25.
Native.
Acid 13
Barytes 84
Water 3
Artificial.
33
64
3
too
100
By another analyfis, when the artificial fulphate
was heated to rednefs, the component parts were found
according to
4 Ann. dc
Chim. xxxii.
p. 266.
t N'thol.
your. li.
Svo. p. 196-
Thenard f.
Acid 25.18
Barytes 74.82
Chenevix \
24
76
100.00
100
2. Sulphite of Barytes.
Prepara- I. This compound of fulphurous acid and barytes,
tion. Is formed by pafling fulphurous acid gas into water, in
which is mixed, or fufpended, carbonate of barytes in
the ftate of fine powTder j or by the direct combination
of fulphurous acid and barytes, either folid or in folu¬
tion. In whatever way it is prepared, the fait is de-
1275 pofited in the form of powder, or cryftallized.
Properties. 2. The crystals of fulphite of barytes are fometimes
in the form of fmall, brilliant, and opaque needles,
or very hard tranfparent cryffals in the form of tetra¬
hedrons, with truncated angles. It has little tafle.
The fpecific gravity is 1.6938. It is fcarcely altered
v.'hen expofed to the air, and is infoluble in water.
When it is expofed to heat, fulphur is driven off, and
there remains a fulphate of barytes. It is decompofed
by the fulphuric and muriatic acids, wfith the difen-
1274 gagement of fulphuvous acid.
'Ufes. This fait has been applied to no ufe, excepting
for the chemical purpofe of afcertaining the purity of
fulphurous acid. It is employed in this way by Four-
croy. If there be any mixture of fulphurous acid
with the fulphuric, it may be detected by this fait j for
as there is a ftronger affinity between fulphuric acid
and barytes than between fulphurous acid and the
fame earth, the fulphuric acid, if any be prefent, com¬
bines'with the Jiarytes, and forms with it an infoluble
1275 fait, which is precipitated. 1
Compofi- 4. The following are the proportions of the confti-
tl0C‘ tjjent parts of this fait.
S T R Y.
Sulphurous acid 39
Barytes 59
Water 2
100 *
3. Nitrate of Barytes.
1. This compound of nitric acid and barytes is pre-Prepara-
pared by faturating the acid with native carbonate offion*
barytes j or, by the decompofition of fulphuret of
barytes, by nitric acid. By filtration and evaporation
this fait cryftalliz.es. 1277
2. The cryffals of nitrate of barytes are in the form Properties,
of regular odlahedrons, or in fmall brilliant plates. The
fpecific gravity is 2.9149. It has a hot, acrid, and au-
llere tafte, and is little changed by being expofed to
the air. It is foluble in 12 parts of cold, and in about
three or four parts of boiling water. When placed
upon burning coals, it decrepitates, boils up, and be¬
comes dry, and gives out fparks round the points
where it comes in contaft rvith the burning coal.
When it is heated in a retort, it gives out a little wa¬
ter, oxygen gas, and azotic gas j and there remains be¬
hind, the barytes in the form of a folid, gray, porous
mafs. 127?
The conftituent parts of this fait, according to Four- Compofi-
croy, Vauquelin, and Kirwan, are the following. tU)n'
Barytes,
See.
# Fourcroy
Connai/s.
Chim. iii,
P- 75-
127S
Fourcroy and Vauquelin f. Kirwan f.
Nitric acid, 38 32
Barytes, 50 57
Water, 12 x 11
100 1CO
This fait is only employed for detefting fulphuric
acid in nitric acid, and to be decompofed for the pur¬
pofe of obtaining pure barytes.
4. Nitrite of Barytes.
Nothing farther is known of this fait, than that it is
formed when the nitrate of barytes is decompofed in
a retort by means of heat. If the operation be flop¬
ped at the time that a third part of the oxygen gas
has been difengaged, the nitrite of barytes remains.
5. Muriate of Barytes. l2y9
1. This fait, which is a compound of muriatic acid Hrftory.
and barytes, w’as firft inveftigated by Scheele and
Bergman, and little more has been fince added by the
experiments and refearches of other chemifts.
2. It is prepared by the direft combination of mu-^ePara'
riatic acid with the carbonate of barytes ; or, by de-
compofing the fulphuret of barytes by the muriatic
acid, filtering the folution, and evaporating till a pel¬
licle appear on the furface. If it be allowed to cool
flowly, cryftals of muriate of barytes are formed. But
the fulphate of barytes, which is employed, fometimes
contains iron 4 fo that a muriate of this metal is form¬
ed along wdth the muriate of barytes. To feparatsthe
iron, the mixture is to be calcined, by which the acid
is driven off, and the iron remains behind in the ftate
of oxide, which is infoluble in water.
3. The primitive form of the cryftals of this fait is Properties.
a
f Ibid. iii.
p. 106.
t Nichol.
your. Hi.
p. 115.
2
Barytes,
&c.
1283
Of heat.
1284
Of acids.
1285
Compoli-
tkm.
1286
Ufes.
a four-fided prifm with fquare bafes. The form of the
integrant particle is the fame. It cryftallizes in tables,
or in eight-fided pyramids. The tafle is acrid, aftrin-
gent, and metallic. The fpecific gravity is 2.8257.
4. It undergoes no change by expofure to the air.
It is foluble in five or fix parts of cold water, but boil¬
ing water difl'olves more ; and, on cooling, the fait
cryltallizes.
5. When expofed to heat, it decrepitates, lofes its
water of cryftallization, dries, falls down to powder,
and at laft melts j but no heat that can be applied de-
compofes it.
6. This fait is decompofed by the fulphuric and ni¬
tric acids, and a precipitation of nitrate or of fulphate
of barytes is formed.
7. The conftituent parts of this fait, according to
Mr Kirwan, are,
When dried.
Acid, 20 23.8
Barytes, 64 76.2
Water, 16 00.0
100 100.0
CHEMISTRY. 591
pofed by the flronger acids it is accompanied with a Barytes,
fiafh of light, which Mr Chenevix conjectures, is ow- ^cc' ,
ing to the relative proportionate affinities, and confe-
quently the greater rapidity of the difengagement.
The proportions of this fait are, tion^0^*
Hyperoxymuriatic acid, 47.0
Barytes, 42.2
Water, io.8
8. This is one of the molt delicate tells for detect¬
ing fulphuric acid in any folution. Water, which
hokTs 0.0002 parts of fulphuric acid, exhibits a vifi-
ble precipitate by a fingle drop of the folution of mu¬
riate of barytes. Nay,, there is a flight cloud in a few
minutes produced by the addition of a folution of this
fait to water, which holds 0.00009 parts of fulphuric
acid in folution. The muriate of barytes has been
propofed and recommended as a cure for fcrophula ;
and it is faid, in fome cafes in which it has been ufed,
with good effeCt •, but it ought to be adminiftered with
the utmoft caution. The carbonate of barytes is one
of the molt aClive poifons, and probably all the falls
of this earth are poflefled of fimilar properties. The
* Fourcroy (hoyjg not exceed five or fix drops of the folution
Ccmnaifs. *
CMm. lii. at hrlt *
p. 167.
1287
Prepara¬
tion.
6. Hyperoxymuriate of Barytes.
1. The compound of hyperoxymuriatic acid and ba¬
rytes was formed by Mr Chenevix. The procefs
which he followed was, to caufe a current of oxymuri-
atic acid gas to pafs through a folution of a large
quantity of barytic earth in warm water. This fait
he found foluble in four parts of cold, and lefs of
warm water y but as it cryltallizes like the muriate of
this earth, and has the fame degree of folubility, he
could not feparate the hyperoxymuriate from the mu¬
riate, which was formed at the fame time. He there¬
fore thought of obtaining it by double affinity, as in
the following procefs.
2. When phofphate of filver is boiled with muriate
of barytes, a double decompofition takes place ; mu¬
riate of filver and phofphate of barytes are formed,
both of which being infoluble, are precipitated. But
the phofphate of lilver does not decompofe the hyper¬
oxymuriate of barytes. When therefore the muriate
and hyperoxymuriate of barytes are boiled with phof¬
phate of filver, the muriate of barytes only is decom¬
pofed. The muriate of lilver and the phofphate of
barytes are precipitated, and the hyperoxymuriate of
barytes remains in folution. When this fait is decom-
100.0 *.
* Phil.
‘Tranf.
1802*
p. 147.
1289
7. Fluate of Barytes.
This compound of fluoric acid and barytes may be
formed, by pouring fluoric acid into a folution of ni¬
trate or muriate of barytes. A precipitate is formed,
which is the fluate of barytes. This fait is decompo¬
fed with effervefcence by the fulphuric acid, and it is
precipitated by lime water. Of the proportions of its
conllituent parts and other properties nothing is
known.
8. Borate of Barytes.
The compound of boracic acid and barytes is form¬
ed by pouring a folution of boracic acid into a folution
of barytes. An infoluble white powder is precipitat¬
ed, which, according to Bergman, may be decompo¬
fed, even by the weak vegetable acids.
9,. Phofphate of Barytes.
1. The compound of phofphoric acid and barytes, has Prepara-
been only examined by Vauquelin. It is prepared,tl0n*
either by the direct combination of phofphoric acid
with barytes, or the carbonate of barytes 5 or by pre¬
cipitating a folution of nitrate or muriate of barytes,
by means of an alkaline phofphate. The phofphate
of barytes is precipitated in the form of powder. 1290
2. This fait is in the form of white powder, with-Properties,
out any appearance of cryflallization. It is not alter¬
ed by expofure to the air, and is infoluble in water.
The fpecific gravity is 1.2867. 1291'
3. This fait at a high temperature is fufible. It is Adtion
converted into a vitreous matter or gray enamel. Be-^eat‘
fore the blow-pipe, on charcoal, it gives out a yellow
phofphoric light. The vitreous globules become
opaque on cooling. It is decornpofed by the fulphu¬
ric acid. The phofphoric and phofphorous acids,
when added in excefs, have the property of re dif-
folving the falts which they form with barytes.
10. Phofphite of Barytes.
129s
This compound of phofphorous acid and barytes, is Prepara-
formed by the direft combination of the acid with the1-*011',
earth ; or by precipitating the foluble phofphites by a
folution of barytes. By the laft procefs the fait is ob¬
tained in the greateft purity. . I2^
2. The phofphite of barytes is in the form of a Properties,
white powder, which is infipid, not altered by ex¬
pofure to the air, not very foluble in water, and with¬
out an excefs of acid, by which means it is converted
into the acidulous phofphite. I2^
3. The phofphite of barytes melts under the blow-Aftion of
pipe into a globule, which is foon furrounded with aiieat*
molt brilliant light. The vitreous globule becomes, on
cooling, white and opaque. J 129$
4. This fait is decompofed by molt of the acids 5 by Of acids,
lime
S92
Barites,
&c.
1296
Compoli-
tion.
Fourcroy
Connaifs.
Cbit/i. iii-
p. 281.
1297
Names.
1298
Native.
1299
Prepared
by art.
1300
Action or
ieat.
1301
Compou-
tion.
C H E M
lime and lime water. The other alkaline and earthy
bafes combine with the excefs of phofphorous acid,
when it is in the ftate of acidulous phofphite, and
there remains behind a neutral phofphite.
;. The component parts of this fait are,
I S T R Y.
When both the natural and artificial are expofed to a
red heat, the component parts, as afcertained by Mr
Kirwan, are,
Acid 22
Barytes 78
Phofphorous acid, 41.7
Barytes, 51.3
Water, 7.0
100.0 *.
11. Carbonate of Barytes.
1. This compound of carbonic acid and barytes has
been known by the names of aerated heavy fpar, ae¬
rated barofelenite and witherite from the name of Dr
Withering, who firft difcovered that it is a natural
production. Its nature and properties were firft invef-
tigated by Scheeie and Bergman, about the year I77^»
and fince that time by Kirwan, Hope, Klaproth, Pel¬
letier, Fourcroy, and Vauquelin.
2. The carbonate of barytes is found native in ftri-
ated, lamellated, femitranfparent mafles. The primitive
form of its cryltals is the fix-fided prifm. I he fpecific
gravity is 4.331.
3. The carbonate of barytes may be prepared artifi¬
cially, by expofing a folution of pure barytes to the
air j or, by pafling carbonic acid gas into the folution.
It may be prepared alfo in the dry way, by mixing to¬
gether fulphate of barytes and carbonate of potafli or
ibda, and expofing the mixture to ftrong heat : or, by
decompofing by means of the carbonate of potafh, fo-
da, or ammonia, the nitrate or muriate of barytes in
folution in water. By whatever proceffes the carbo¬
nate of barytes is obtained, it is in the form of a white
taftelefs powder. When thus prepared, the fpecific
gravity is 3.763.
4. It undergoes no change by expofure to the air.
Cold water diffolves x\oK '■> boiling water yyVi part.
. 5. The carbonate of barytes undergoes little change
when it is expofed even to the ftrongeft heat. The
artificial carbonate lofes about 0.28 of its weight by
calcination, while the native carbonate becomes white
and opaque, and is converted into a bluifir green co¬
lour, without any perceptible lofs of weight *, but if it
be heated in a black lead crucible, or if it be formed
into a pafte, with 100 parts of the fait to IQ of char¬
coal, the carbonic acid is feparated.
6. The component parts of the carbonate of barytes
are the following :
Native Carbonate.
Withering. Fourcroy.
Acid 20 IO
Barytes 80
90
100
100
Bergman.
Acid 7
Barytes 65
Water 28
Artificial Carbonate.
Pelletier.
22
62
l6
IOO
100
too
I30®
7. This fait has been found native only 111 fmall ufes.
quantity, otherwife it is fuppofed, that it might be of
great ufe for the preparation of barytic falts, which
promife great lervice in feveral arts and manufadimes.
It has been propofed to employ it in medicine ; but in
experiments on animals, it has been found to aft as a
moft deadly poifon. Great caution, therefore, Ihould
be obferved in employing it as an internal remedy *. * Fourcrcyt
12. Arfeniate of Barytes.
IV. 10.
The compound of arfenic acid and barytes is formed
by diffolving the earth in the acid. It is an infoluble,
uncryflallized fait *, but with an excefs of acid it be¬
comes foluble, and is decompofed by fulphuric acid.
It melts when expofed to a ftrong heat, but is not de¬
compofed.
13. Tungftate of Barytes.
With the tungftic acid barytes forms an infolublc
fait.
14. Molybdate of Barytes.
Barytes with the molybdic acid forms a fait which
has very little folubility.
15. Chromate of Barytes.
It is little known, but faid to be infoluble in w'ater.
16. Columbate of Barytes.
17. Acetate of Barytes.
x. This fait, which is a compound of acetic acid prepara-
and barytes, may be prepared by direftly combining tion.
the acid with the earth 3 or, by decompofing fulphuret
of barytes by means of acetic acid. By evaporating
the folution, it may be obtained cryftallized. ^04
2. The cryftals of the acetate of barytes are in the Proper ties.-
form of fine tranfparent prifms. The fpecific gravity
is 1.828. This fait has an acid bitter tafte, efflorefces
in the air, is very foluble in water, is decompofed by
the carbonates of the alkalies, but not by the alkalies
themfelves, or the pure earths.
3. This fait may be employed to deteft the prefence ufes.
and quantity of fulphuric acid in folutions, particularly
in vinegar, which may be adulterated with the addition
of this acid f. t Fourcroy,
vuu 196.
18. Oxalate of Barytes.
1. The compound of oxalic acid and barytes is form- Prepara-
ed by adding the acid to a folution of barytes in water, tion.
A w hite powder precipitates, which is oxalate of bary¬
tes ■, it is infoluble in water. With an excefs of oxalic
acid, this precipitate is diflblved, and fmall angular
cryftals are formed. 1307
2. If thefe cryftals are diflblved in boiling water, Adhon of
they become opaque, and fall down in the form of anlieat'
infoluble
e H E M
Barytes,
See.
infoluble powder, for the water combines with the ex-
cefs of acid, which held them in folution.
19. Tartrate of Barytes.
The compound of tartaric acid and barytes forms a
fait in the date of white powder, which has little folu-
bility, excepting with an excefs of acid. It is d.ecom-
pofed by the fulphuric, nitric, muriatic, and oxalic
acids.
20. Citrate of Barytes.
1308
Prepara- I. The compound of citric acid and barytes forms
.fiyn. a fait, by adding the earth to a folution of the acid.
A flocculent precipitate at firft appears, which is dif-
folved by agitation. The precipitate afterwards be¬
comes permanent when the acid is faturated.
2. This fait, which is at firft depofited in the form
of pow’der, {hoots out afterwards into a kind of vege¬
tation, of a filvery whitenefs, with great brilliancy
and beauty. It is foluble in a great proportion of wa¬
ter. This fait is compofed of
Acid 50
Barytes 50
IOO
21. Malate of Barytes.
The compound of malic acid and barytes is formed
by adding the acid to a folution of the earth in water.
A cryftallized, foluble fait is precipitated.
2 2. Gallate of Barytes.
The compound of gallic acid and barytes is formed
by the direfl combination of the acid with the earth.
A fait is thus formed, which is not very foluble, but
with an excefs of the bafe.
23. Benzoate of Barytes.
The benzoic acid combines with barytes, and forms
Sa fait which is foluble in water, cryftallizes, undergoes
no change by expofure to the air, and is decompofed
by heat and the ftronger acids.
24. Succinate of Barytes.
Barytes forms, with fuccinic acid, a fait which has
little folubility.
25. Saccolate of Barytes.
This fait is infoluble in wrater.
26. Camphorate of Barytes.
Prepara- r* compound of camphoric acid and barytes is
tion. " formed by adding th* cryftallized acid to the folution
of the earth, and then boiling the mixture. It is after¬
wards to be filtered and evaporated to drynefs. What
remains is camphorate of barytes.
Properties. 2’ This fait does not cryftallize ; but when it is
flowly evaporated, fmall plates are depofited, which
feem tranfparent in the liquid, but become opaque
when expofed to the air. It has fcarcely anv tafte ;
but an impreffion remains on the tongue, which is
{lightly acid and bitter.
3. This fait undergoes no change by expofure to
Vot. V, Part II.
1 str y. 593
the air. It is only foluble in 600 parts of water at the Strontites.
boiling temperature. &-c.
4. When expofed to the a£lion of the blow-pipe,' x ^ ^
the acid is volatilized, and the earth is converted into Adtion^f
a vitreous fubftance. The camphoric acid, as it burns,heat,
firft exhibits a blue, then a red, and at laft, a white
flame.
5. This fait is decompofed by the fulphuric, nitric,
and muriatic acids, and by the oxalic, tartaric and ci¬
tric *.
27. Suberate of Barytes.
This fait does not cryftallize, is only foluble in wa¬
ter w'ith an excefs of acid j when expofed to heat, it
fwells up and melts, and is decompofed by the fulphu-
ric, nitric, muriatic, and oxalic acids f.
28. Mellate of Barytes.
* Ann. ds
Chim.
xxvii.p.zl.
t Ibid.
xxiii. 52V
By adding mellitic acid to a folution of acetate of
barytes, there is formed a flaky precipitate which is
re-difiblved with the addition of more acid. When
the acid is poured into a folution of muriate of barytes
no precipitate is formed j but a {hort time afterwards
a group of tranfparent needle-formed cryftals is de¬
pofited.
29. Laftate of Barytes.
Barytes forms with laftic acid, a deliquefeent fait.
30. Prufliate of Barytes.
Pruflic acid and barytes form a fait which is very
little foluble in w’ater, and is decompofed, not only by
the fulphuric acid but even by carbonic.
31. Sebate of Barytes.
Sebacic acid added to a folution of barytes in water,
forms no precipitate ; from which it is inferred that
the febate of barytes is foluble in water.
Sect. III. Of Strontites and its Combinations.
1. This earth was not difeovered till about the yearH-^31!!
1791 or 1792. Dr Crawftord, indeed, previous to 1 °ly'
this period, in making fome experiments on what he fup-
pofed was a carbonate of barytes, and obferving a link¬
ing difference between this mineral, and the carbonate
of barytes which he had been accuftomed to employ,
conje&ured that it might contain a new earth ; and
he fent a fpecimen to Mr Kirwan for the purpofe of
analyzing it. This conjedlure was fully verified by
the experiments of Dr Hope X, Mr Kirwan, and M. f £di«.
Klaproth, who were all engaged in the fame analyfis TVa*/
nearly about the fame time. This earth is found na-iv-3'
tive in combination with carbonic and lulphuric acids.
"With the former it is found in confiderable quantity in
the lead mines of Strontian in Argyleihire, from which
it has derived its name frontites, or Jirontian, as it is
called by others. The nature and properties of this
earth have been flill farther inveftigated by Pelletier,
Fourcroy, and Vauquelin.
This earth may be obtained in a ftate of purity, ei- prepanf.
ther by expofing the carbonate of ftrontites mixed with tion.
charcoal powder, to a ftrong heat, by which the car¬
bonic acid is driven off j or, by diflblving the native
4 F fait
\
594
Strontites,
8cc.
1314
Properties.
*3*5
Action of
heat.
1316
Of water.
*3*7
Affinities.
C H E M
fait in nitric acid, and decompofing the nitrate of
ftrontites thus formed, by heat. Strontites obtained
by either- of thefe proceffes, is in fmall porous frag¬
ments of a greeniih white colour. It has an acrid,
hot, alkaline tafte, and converts vegetable blues to
green. The fpecific gravity is 1.647.
3. Light has no perceptible aftion upon this earth.
When it is expofed to heat, it may be kept a long
time, even in a red heat, without undergoing any
change, or even the appearance of fufion. By the ac¬
tion of the blow-pipe it is not melted, but is furround-
ed with a very brilliant white flame.
4. When a little water is thrown on ftrontites, it
exhibits the fame appearance as barytes. It is flaked,
gives out heat, and then falls to pow’der. If a great¬
er quantity of water be added, it is diffolved. Ac¬
cording to Klaproth it requires 200 parts of water at
the ordinary temperature of the atmofphere for its fo-
lution. Boiling water diffblves it in greats* quantity,
and when the folution cools, it affords tranfparent cry-
flals. Thefe cryftals are in the form of rhomboidal
plates, or in that of flattened filky needles, or com-
preffed prifms. The fpecific gravity is 1.46. Thefe
Cryftals efflorefce in the air, and have an acrid hot
tafte. The folution of this earth in water is acrid
and alkaline, and converts vegetable blues to green.
It is foon covered with a pellicle, by abforbing carbo¬
nic acid from the atmofphere.
5. Strontites has the property of communicating a
purple colour to flame.
6. The order of the affinities of ftrontites is the fol¬
lowing.
Sulphuric acid,
Phofphoric,
Oxalic,
Tartaric,
Fluoric,
Nitric,
Muriatic,
Succinic,
Acetic,
Arfenic,
Boracic,
Carbonic.
I. Phofphuret of Strontites.
The phofphuret of ftrontites is prepared in the fame
way as the phofphuret of barytes.
1318
Prepara¬
tion.
II. Sulphuret of Strontites.
The fulphuret of ftrontites is formed by expofing
fulphur and the earth in a crucible, to heat. This ful¬
phuret is foluble in water, by means of fulphurated hy¬
drogen, which is difengaged by the decompofition of
the water. The ftrontites thus combined with fulphu¬
rated hydrogen, forms a hydrofulphuret of ftrontites;
and if this folution be evaporated, the hydrofulphuret
of ftrontites may be obtained in cryftals, and the hy¬
drogenated fulphuret remains, as in fimilar compounds,
in folution. When the hydrogenated fulphuret is de-
compofed by means of an acid, the fulphurated hydro¬
gen gas which is difengaged, burns with a beautiful
purple flame, on account of holding in folution a fmall
quantity of the earth, which communicates this pro-
perty.
I S T R Y.
III. Compounds of Strontites with the Acids.
I. Sulphate of Strontites.
Strontites,
&LC.
1. The compound of fulphuric acid with ftrontites,
may be formed by adding fulphuric acid to a folution
of ftrontites in water, and it is obtained in the ftate of
a white powder. It is found native in different places,
cryftallized in fine needle-formed prifms. It has no
tafte, and is fcarcely foluble in water. It fuffers no
change in the air. By the aftion of the bhnv-pipe it
gives out a yellowifti purple light. It is not decom-
pofed by any of the acids $ but it is decompofed by the
carbonate of potalh and foda, by the barytic falls, by
the fulphates of potafti and of foda, the phofphates of
potafh, foda, and ammonia, and by the borate of am¬
monia.
2. The component parts of this fait, according to
Vauquelin, are,
Acid, 46
Strontites, 54
IOO
But according to Klaproth, Kirwan, and others,
Acid, 42
Strontites, 58
100
2. Sulphite of Strontites.
This fait is yet unknown.
3. Nitrate of Strontites.
1. The compound of nitric acid and ftrontites, is form¬
ed by precipitating, by means of the nitric acid, the
fulphuret of ftrontites, obtained from the decompofed
fulphate, or by diffolving the carbonate of ftrontites in
the acid. By evaporation it may be obtained in cryf- ,
tals.
2. The cryftals of nitrate of ftrontites are in the
form of o&ahedrons. The tafte of this fait is cool and
pungent. It is not altered by expofure to the air.
The fpecific gravity is 3.0061. It is foluble in 15
parts of cold water, and much more foluble in boiling
water, in which it cryftallizes on cooling. Expofed to
fudden heat, it decrepitates. When it is fubjefted to
heat in a crucible, it fwells up, gives out oxygen and
nitrous gas, and there remains behind pure earth.
This fait has the property of communicating a purple
flame to combuftible fubftances with which it is mixed j
as when a little of the fait in powder is thrown on the
wick of a candle.
3. The component parts of this fait, are according
to
Vauquelin. Kirwan.
Acid 48.4 31.7
Strontites 47.6 3^-21
Water 4.0 32,72
100.0 100.00
4. Nitrite of Strontites.
The properties of this fait have not been examinecfo
5. Muriate
C H E M
Strontites,
&c.
1319
Prepara¬
tion.
1320
Properties.
I32t
Compofi-
tion.
1322
Prepara¬
tion.
1323
Compoii-
tion.
* Phil.
Tr-anf,
£802.
j. Muriate of Strontites.
1. The compound of muriatic acid and ftrontites is
prepared by diflblving carbonate of ftrontites in the
acid. By evaporating the folution, the fait is obtained
cryftallized.
2. This fait cryftallizes in long, (lender hexagonal
prifms. The tafte is cooling and pungent. The fpeci-
fic gravity is 1.4402. It is not altered by expofure to
the air. It is very foluble in water. Three parts of
the fait are diffolved in two parts of cold water. Thefe
cryftals, which are foluble in alcohol, communicate a
purple colour, which is the diftinguiftiing charadfteriftic
of this fait. When heated, it melts, and parts with its wa¬
ter of cryftallization, without being decompofed, and
there remains behind a femitranfparent enamel. This fait
is decompofed by a very ftrong heat. It is decompofed
alfo by the fulphuric, nitric, and phofphoric acids j and
by potafti, foda, and barytes.
3. The conftituent parts of this fait are, according
to
Vauquelin.
Acid 23.6
Strontites 36.4
Water 40.0
Kirwan.
18
40
43
100.0
100
100
2324
Prepara¬
tion.
I32S
Properties.
7. Fluate of Strontites.
The properties of this fait have not yet been in-
veftigated.
8. Borate of Strontites.
This compound of boracic acid and ftrontites, is in the
form of a white powder, and requires 130 parts of wa¬
ter for its folution. It converts the fyrup of violets to
a green colour, from which it is inferred, that it con¬
tains an excefs of the earth.
9. Phofphate of Strontites.
1. The compound of phofphoric acid and ftrontites,
is formed by diifolving the carbonate of the earth in
acid \ or, by mixing together the folutions of muriate
of ftrontites, with thofe of the alkaline phofphates.
2. It is thus obtained in the form of white powder,
which is perfeflly taftelefs. It is not altered by ex¬
pofure to the air. It is infoluble in water, without
an excefs of acid. It melts under the hlow-pipe into
I S T R Y. 595
a white enamel, and gives out a purple, phofphorefcent Strontites,
iight. . ^c- ,
3. The conftituent parts of this fait are,
Acid 41.24
Strontites 58.76
100.00
6. Hyperoxymuriate of Strontites.
t. This combination of hyperoxymuriatic acid and
ftrontites, was prepared by Mr Chenevix, by a ftmilar
procefs to that which he employed in the formation of
barytes with the fame acid j and in many of its proper¬
ties it is analogous.
2. The cryftals of this fait are in the form of needles.
They melt in the mouth, and give the fenfation of
cold. It is compofed of
Acid 46
Strontites 26
Water 28
10. Phofphite of Strontites.
The nature of this fait is unknown.
11. Carbonate of Strontites.
1326
1. This fait is found native, and, as we have already Found na-
mentioned, was pointed out by Dr Crawford as diffe-dve*
rent from the carbonate of barytes, with which it had
been formerly confounded.
2. It may be prepared artificially, by faturating a folu- Prepara¬
tion of ftrontites in water with carbonic acid j or, bytl0I!'
precipitating foluble falls with a bafe of this earth,
by means of alkaline carbonates. The carbonate of
barytes cryftallizes in needles, or in fix-fided prifms.
It has no tafte. The fpecific gravity is 3.6750. It
is not changed by expofure to the air, and it is nearly 1328
infoluble in water. When it is ftrongly heated in aProPertie?
crucible, to produce fufion, it is deprived of part of
its carbonic acid. When heated under the blow-pipe,
it melts into an opaque, vitreous globule, and gives
out a purple flame. 1329
2. The component parts of this fait, according to Compofi-
dift'erent chemifts, are t1012.
Hope.
Acid 30.2
Strontites 61.2
Water 8.6
Klaproth and Kirwan. Pelletier.
30. 3°
69.5 62
0.5 8
100.0
10070
ICO
12. Arfeniate of Strontites.
When arfenic acid is dropped into a folution of
ftrontites in water, a copious precipitate is formed,
which is re-difTolved when there is an excefs of acid.
When the arfeniate of ftrontites is neutralized, it is
only in a (light degree foluble in water *. * Ed'm,
Pranf. iv»
Tungftate of Strontites.
Molybdate of Strontites.
Chromate of Strontites.
Columbate of Strontites.
13-
14.
15-
16.
}
17-
unknown.
1330
17. Acetate of Strontit^s.
1. This compound of acetic acid and ftrontites isprepara-
formed by diflblving the carbonate in the acid. Bytion.
evaporation the fait may be obtained cryftallized.
2. The cryftals remain unaltered by expofure to the Properties,
air. They change vegetable blues to green, and are
equally foluble in hot and cold water f.
18. Oxalate of Strontites. p‘ I4’
The compound of oxalic acid and ftrontites is form¬
ed by the diredl; combination of the acid with the earth
in folution. A precipitate appears in the form of a
white powder, which is nearly infoluble in water. It
is decompofed by heat.
4 F 2 The
596
Magnefia,
&cc.
CHE
The component parts of this fait are,
Acid
Strontites
4°-5
59-5
100.0
19. Tartrate of Strontites.
1. This fait is formed by dilfolving the earth in the
acid. The cryftals are in the form of fmall triangu¬
lar tables j they are not altered by the air, are infipid
to the tafte, and foluble in 320 parts of boiling water.
2. The conftituent parts of this fait are,
Acid and water
Strontites
47.12
52.88
100.0
20. Citrate of Strontites.
1. This combination of citric acid with ftrontites
may be formed by mixing together a folution of ni¬
trate of ftrontites and citrate of ammonia. A double
decompofttion takes place, but no precipitate is form¬
ed. By flow evaporation, cryftals of citrate of ftron¬
tites may be obtained.
2. This fait is foluble in water.
21. Malate of Strontites.
This fait is fcarcely known.
22. Gallate of Strontites.
Little known alfo.
23. Benzoate of Strontites.
Unknown.
24. Succinate of Strontites.
Succinic acid combines with ftrontites, and forms
cryftals, which may be obtained by flow evapora¬
tion.
25. Camphorate of Strontites.
26 Suberate of Strontites.
27. Mellate of Strontites.
28. Ladlate of Strontites.
29. Prufliate of Strontites.
30. Sebate of Strontites.
> unknown.
Sect. IV. Of Magkzsia and its Combinations.
1332
Hiftory. I. Magnefia was firft knowm about the beginning
of the 18th century, when it was fold by a Roman ca¬
non, under the name of magnejia a/ba, or white mag-
nejia, and the powder of the. count of Pa/ma, as a cure
for difeafes ) and like many new remedies, it was con-
ftdered as univerfal. In the year 1707, Valentini dif-
covered that this boafted panacea was the produce of
the calcined ley which remains after the preparation of
nitre. He gave it the pompous name of the laxative
powder of many virtues. In the year 1709, Slevogt
defcribed the method of obtaining it by precipitation,
from the mother ley of nitre. Lancifi and Hoffman
examined fome of its properties in 1717 and 1722 j
and although the latter difcovered that it formed dif-
M I S T R Y.
ferent combinations with acids from thofe of lime, it Magnefia,
was generally confounded with this fubftance. , ^•c* .
But the nature of magnefia was not fully known, " ’
till Dr Black, in 1755, entered upon his celebrated
inveftigations of the different properties of this fub¬
ftance, lime and the alkalies, in the mild and cauftic
ftate. Margraaf publiftied the refult of his experi¬
ments and refearches on it in 1759* in which he gave
many diftin&ive characters of this earth, and of its
combinations •, and, at laft, by the obfervations of
Bergman, publiftied in 1775, and thofe of Butini of Ge¬
neva in 1779, the nature and properties of magnefia
were fully demonftrated.
2. Magnefia, although it exifts in great abundance Prepara-
in combination with other fubftances, has never been tion.
found perfeftly pure in nature. The procefs by which
it may be obtained in greateft purity, is the following.
A quantity of Epfom fait, which is a compound of ful-
phuric acid and magnefia, is to be diffolved in water,
and then precipitated by potafti. The precipitate
which is formed, is to be well walked and dried, both
with cold and hot water, to feparate any faline matters
with which it may be mixed. The nature of this pro¬
cefs is obvious. The potafli has a ftronger affinity for
fulphuric acid than magnefia. It therefore combines
with the acid, and the magnefia is precipitated.
3. Magnefia, when it is obtained pure, is in the pr0pertieSy
form of a fine white powder, or in v\hite friable cakes
refembling ftarch. It has no fmell, and no fenfible
tafte j but becomes dry, and leaves on the tongue a
flight fenfation of bitternefs. Its fpecific gravity, ac¬
cording to Kirwan, is 2.330. It gives a flight tinge
of green to fyrup of violets, or other delicate vegeta¬
ble blues.
4. Magnefia is not aCled upon by light,
melted when expofed to the greateft heat. By ftrong heat,
calcination it becomes finer, whiter, and more friable.
When it is expofed to heat in the form of pafte with
wrater, it contraCls its dimenfions, and acquires a
phofphorefcent property *, for wdien it is ftrongly rub¬
bed on a hot iron plate, it becomes luminous in the
dark. It is not altered by the aClion of the blowT-pipe
on charcoal, but gives out a flame of a flight yellow
colour.
5. There is no aflion between magnefia and oxy-ofair.
gen or azote. When expoled to the air, it attracts a
little moifture from the atmofphere, but this goes on
very flowly.
Butini expofed a quantity of magnefia for the fpace
of tw7o years in a porcelain cup flightly covered with
paper, and he found that it had acquired only X-Lp
part of its weight in addition, during that time.
6. There is no aftion between magnefia and hydro¬
gen or carbone, and very little between it and phof-
phorus.
7. Magnefia is very little foluble in water. Ac-Of water,
cording to Mr Kinvan, it requires near 8000 times its
weight of cold water to diffolve it. Butini found, that
wrater boiled wdth this fubftance and left in contact
with it for three months, had fcarcely acquired to-soo7
part of its weight j but water combines with magnefia
in the folid ftate. One hundred parts of magnefia,
according to Bergman, thrown into water, and taken
cut and dried, acquired 18 parts of additional weight.
8. Magnefia enters into combination wfith the acids, Affinities^
and
T • t 1335
It is not Adtiou of
C H E M
Jvfagnefia, and forms with them peculiar falts. The order of its
, &c' , affinities is the following, according to Bergman.
Oxalic acid,
Phofphoric,
Sulphuric,
Fluoric,
Arfenic,
Saclaftic,
Succinic,
Nitric,
Muriatic,
Tartaric,
Citric,
Laftic,
Benzoic,
Acetic,
Boracic,
Sulphurous,
Carbonic,
Pruffic.
1339
Of earths.
*34°
Ufes.
1341
Prepara¬
tion.
’»342
Properties.
* Fourcroy
Connaifs,
Chim, ii.
161.—167.
1343
Hiftory.
9. Magnefia does not enter into combination -with
the fixed alkalies; but in combination with fome of the
earths, it becomes fufible by means of a ftrong heat.
With lime in certain proportions, it forms a greeniffi
yellow glafs.
10. Magnefia is much employed in medicine as a
gentle laxative, and as an abforbent to deftroy the
acidity in the ftomach. It is ufed in pharmacy to fuf-
pend or aid the folution of refinous and gummy fub-
ftances, fuch as camphor and opium, in water, which
are otherwife little foluble.
I. Of Sulphuret of Magnefia.
1. Magnefia enters into combination with fulphur,
either in the dry or humid way. Two parts of mag¬
nefia and one of fulphur, put into a crucible, and ex-
pofed to heat, form an orange yellow mafs, which is
not very foluble in w'ater, but emits the odour of ful-
phurated hydrogen gas, wThen it comes in contact with
that liquid, and which is very readily decompofed by
means of heat. The heat that is applied to obtain
this fulphuret muft be very moderate, otherwife the
fulphur is driven off.
2. The fulphuret of magnefia is formed with more
difficulty in the humid way. When two parts of mag¬
nefia and one of fulphur in powder, with 20 parts of
water, are expofed to heat on a fand bath, the liquid
becomes of a pale yellow colour, which is llightly fe¬
tid, but has nothing of the ftrong odour of the other
fulphurets. There is formed very little of the fulphu¬
ret of magnefia •, for the greateft part of the fulphur
and magnefian earth remains uncombined. There is
very little fulphurated hydrogen produced, the water
fcarcely exhaling the odour of this gas.
3. The folid fulphuret of magnefia decompofes ra¬
pidly, when expofed to the air. It feems to abforb
very little fulphurated hydrogen gas ; fo that the pro¬
perties of the hydrofulphuret of magnefia are yet un¬
known *.
II. Compounds of Magnefia with Acids.
1. Sulphate of Magnefia.
The compound of fulphuric acid and magnefia was
formerly known under the name of Epfom and Seidlit%
I s T R Y. 597
falts, becaufe it exifts in the rvaters of thefe fprings, Magnefia.
andyh/ cntharticus amarus, bitter purging fait, on ac-, ^~c‘ ,
count of its properties. It was long confounded with
fulphate of foda, till its properties were inveftigated by
Black, Macquer, and Bergman, and its nature and
compofition fully afcertaincd. 1344
2. This fait exifts abundantly in nature. It isPrepara-
found in many mineral fprings, and it forms a confider-ti0n‘
able proportion of the faline ingredients of fea water.
The bittern or mother water of common fait, that is,
the water w'hich remains after the cryftallization, con-
fifts chiefly of fulphate of magnefia. It is therefore
rarely prepared by art, by the direct combination of
its conftituent parts. It is eafily purified by diffolving
the fait in water, and by evaporation and cryftalliza¬
tion. 1345
3. The fulphate of magnefia thus prepared, is cry-Properties
ftallized in four-fided prifms, terminated by four-fided
pyramids. There is, however, fome deviation from
this form. The primitive form of the cryftal is a qua¬
drangular prifm with fquare bafes. The integrant
molecule is a triangular prifm, wffiofe bafes are right-
angled ifofceles triangles. It has a cool, bitter tafte.
The fpecific gravity is 1.66. 1345
4. Expofed to the air, it efflorefces. It is foluble Aifticn of-
in its own weight of cold water : boiling water dif-waterand
folves more than two-thirds of its weight. Expofed eat‘
to heat, it undergoes the watery fufion, and being de¬
prived of its water of cryftallization, it does not melt,
nor is it decompofed by the ftrongeft heat. By the
aftion of the blow-pipe it melts with difficulty into an
opaque, vitreous globule. -347
5. The fulphate of magnefia is decompofed by the Of alkalies*
fixed alkalies, but with ammonia it forms a triple fait. I348
The component parts of this fait are, according to ^°™p°ri"
Bergman.
Sulphuric acid 33
Magnefia 19
Water 48
Kir wan.
In cryftals. Dry-
29-35 ^d-S2
17.OO 36.68
53.65 00.00
100
100.00
100.00 *.
* Nicbol,
'Jour. iii.
p. 215.
1349
Ufes.
1350
6. The fulphate of magnefia is employed in medicine
as a purgative. From this fait too, the earth of mag¬
nefia is ufually extra&ed-
2. Sulphate of Ammonia and Magnefia.
r. This is-a triple combination of fulphuric acidPrepara-
with ammonia and magnefia. It is prepared by theUon-
partial decompofition of the fulphate of magnefia by
means of ammonia. By evaporating the folution the
triple fait is obtained in cryftals.
2. This fait cryftallize^ in odahedrons. It has apr0pert;cs,.
bitter acrid tafte, does not efflorefce in the air, is lefs
foluble in water than either of the falts of which it is
compofed, but it is more foluble in hot than in cold wa¬
ter, and it cryftallizes on cooling. By heat it undergoes
the watery fufion. It then dries and is decompofed.
The component parts of this fait are,
Sulphate of magnefia, 64
of ammonia, 32. * Fourcrrj
  — Connaifs.
IOO * Chim. iii.
3. Sulphate 49-
C H E M
59s
Magnefia,
&c.
1352
Prepara-
< tion.
I3S3
Properties.
1354
Adlion of
air, See.
3. Sulphite of Magnefia.
1. The compound of fulphurous acid and magnefia
is formed by paffing fulphurous acid gas into two parts
of water, with one of carbonate of magnefia. A
violent effervefcence takes place, wdth the evolution of
heat. The fulphite of magnefia is formed, and preci¬
pitated to the bottom in the ftate of powder ; but with
an excefs of acid it is re-diffblved, and cryftallizes.
2. The cryftals of fulphite of magnefia are in the
form of depreffed tranfparent tetrahedrons. It has a
mild earthy talle, which foon becomes fenfibly fulpbu-
reous; it has no fmell. Its fpecific gravity is 1.3802.
3. It efflorefees in the air, and is {lowly convert¬
ed into fulphate of magnefia. It is foluble in 20 parts
of cold water. Boiling water difiblves a greater pro¬
portion, and from this it cryftallizes on cooling. Ex-
pofed to heat, this fait becomes vifeid, and by calcina¬
tion it lofes 0.45 of its weight. If the heat be in-
creafedj it is decompofed ; the acid is driven qIF, and
the pure earth remains behind.
The component parts of this fait are,
1355
Prepara¬
tion.
135^
Properties.
1357
Action of
heat.
I- Told.
p. 89.
I35S
Hiftory
and prepa¬
ration.
*359
Properties.
1350
Adtion of
water.
1361
Of heat.
1362
Com poll-
tion.
I S T R Y.
Bergman.
Acid, 43
Magnefia, 27
Water, 30
Sulphurous acid,
Magnefia,
Water,
39
16
45
4. Sulphite of Ammonia and Magnefia.
1. This triple fait is formed by decompofing the ful¬
phite of ammonia by magnefia, or the fulphite of mag¬
nefia by ammonia, in folution in the cold } or, by mix¬
ing together the folutions of the twm falls.
2. This fait is in tranfparent cryftals, the form of
which has not been determined. When it is expofed
to the air, it is converted into fulphate of ammonia and
magnefia. It is lefs foluble in water than either of the
twm fulphites of which it is formed. By the adlion of
heat, fulphurous acid is given out, acidulous fulphite
of ammonia is fublimed, and there remains behind
pure magnefia f.
5*. Nitrate of Magnefia.
1. This compound of nitric acid and magnefia wTas
formerly called nitre with bafe of magnefa, and mag-
nefian faltpetre. It is formed by the direft combina¬
tion of the acid with the earth. By evaporation it is
cryftallized.
2. This fait cryftallizes in four-fided rhomboidal
prifms, whofe fummits are oblique or truncated. Some¬
times it is in the form of fmall needles combined in
groups. The tafte is penetrating and bitter. The fpe¬
cific gravity is 1.736.
3. It is deliquefeent in the air, and is foluble in its
owm weight of cold w'ater. It is more foluble in boil¬
ing wrater, in wThich it cryftallizes on cooling ; but it
can only be obtained in regular cryftals by flow evapo¬
ration from its folution in cold water.
4. By the a£fion of heat it undergoes the watery
fufion ) the water is driven off, and it becomes dry. It
is decompofed in a ftrong heat, gives out a little oxy¬
gen gas, then nitrous gas, and at laft the nitric acid.
The pure earth remains behind.
The component parts of this fait are, according to
Kirwan.
46
22
32
100
6. Nitrate of Ammonia and Magnefia.
1. This triple fait is formed, either by the direfl
combination of the folutions of nitrate of ammonia,
and nitrate of magnefia, by which the lalt is obtained
pure and cryftallized; or, by partially decompoling
the nitrate of ammonia by magnefta, or the nitrate of
magnefia by ammonia.
2. The cryftals of this fait are in the form of fine
prifms. It has a bitter, acrid, and ammoniacal tafte. It
is lefs deliquefeent in the air than either of the confti-
tuent falls, and lefs foluble in water. It requires
n parts of cold water to diflblve it, but lefs of boiling
water. It cryftallizes on cooling.
When it is rapidly heated, it inflames fpontaneoufly.
When flowly heated in clofe veffels, it gives out oxy¬
gen gas, azotic gas, a greater proportion of water than
it contains, nitrous gas, and nitric acid, without the
fmalleft trace of ammonia j which ftiows that it is de¬
compofed, that the hydrogen combines with the oxygen
of the acid, and forms water.
The component parts of this fait are,
Nitrate of magnefia, 78
Magnefia,
&c.
*3^3
Prepara¬
tion.
1364
Properties.
1365
Aftion of
heat.
*3*6
Compoll-
tion.
IOO
7. Nitrate of Magnefia.
Nothing is known of the properties of this fait.
8. Muriate of Magnefia.
x. This compound of muriatic acid and magnefia
was formerly called marine fait of magnefia, and was
confounded with the muriate of lime, with which it
is frequently accompanied. The difference between
thefe two falls was firft pointed out by Dr Black, and
Bergman afterwards examined the nature and proper¬
ties of muriate of magnefia. The fait is obtained by
diffolving magnefia in muriatic acid till they are fatu-
rated, and then evaporating the folution. Small irregu¬
lar cryftals are obtained. This fait exifts in the waters
of the ocean, and in mineral waters, along with the mu¬
riates of foda and lime.
2. It is extremely difficult to obtain the muriate of
magnefia in any regular form. It is either in the ftate
of powder, or very fmall regular needles, or in a kind
of jelly. It has a difagreeable bitter tafte. The fpe¬
cific gravity is 1.601.
3. It is very deliquefeent in the air. Cold water
readily diffolves its own weight, and it is ftill more fo¬
luble in boiling wrater.
4. It is completely decompofed by heat} the acid is
driven off, and the pure earth remains behind *.
The component parts of this fait are,
Bergman. Kirwan.
Acid, 34 34.59
Magnefia, 41 3I,07
Water, 25 34.38
f Fourcroy
Connaifs.
Cbim. ni.
144.
1357
Found na¬
tive.
136#
Properties-.
JOO
ICO.04 f
9. Muriate
*369
Adlion of
heat.
*310
Compofi-
tion.
Fourcrcyt
iii. 204.
f Nu&ol.
your. iix.
215.
CHEMISTRY.
Magneila,
See.
137*
Properties.
1373
Compoti-
tion.
1374
Compofi-
tion.
* Phil.
Tranf.
1802,
p. 149.
I37S
Prepara¬
tion.
1375
Properties.
9. Muriate of Ammonia and Magnefia.
This triple fait is formed by mixing the folutions of
muriate of magnefia and muriate of ammonia ; and
by evaporating the folution the fait cryftallizes in
the form of fmall polyhedrons. It has a bitter, am-
ammoniacal tafte. It is little altered by expofure to
the air, and is foluble in fix parts of cold water. It is
decompofed by heat. The muriate of ammonia is fub-
limed, and the muriate of magnefia is deprived of its
acid.
The component parts of this fait are,
Muriate of magnefia, 73
27
100
10. Hyperoxymuriate of Magnefia.
This is fimilar in its chemical and phyfical proper¬
ties to the hyperoxymuriate of lime, and it is prepared
in the fame way. It is precipitated by lime and am¬
monia.
The component parts are,
Acid, 60
Magnefia, 25.7
Water, 14.3
100.0
1 faurcrey,
iii. 308.
1377
Prepara¬
tion.
t378
Properties.
%lVii. 319.
1379
Foupd na¬
tive.
1380
Properties.
II. Fluate of Magnefia.
1. This fait is formed by combining together fluoric
acid and magnefia. According to Scheele, it precipi¬
tates in the form of a gelatinous mafs; but Bergman ob-
ferves that great part of the fait is depofited as the fa-
turation approaches. By evaporating the folution,
cryftals in the form of fix-fided prifms, terminated by
a low pyramid compofed of three rhomboidal fides, are
obtained.
2. This fait is not decompofed by the ftrongeft heat,
or by any acid.
12. Fluate of Ammonia and Magnefia.
This triple fait is formed by mixing the folutions of
the fluates of ammonia and magnefia. A precipitation
is formed, which is the triple fait in cryftals. The
properties of this fait are unknown f.
13. Borate of Magnefia.
1. This fait is formed by the direfl combination of
boracic acid with magnefia. The earth is flowly dif-
folved, and wdien the folution is evaporated, cryftals are
obtained.
2. The cryftals of this fait are very fmall and irregu¬
lar. It melts when expofed to heat, without being
decompofed ; but it may be decompofed, it is faid, by
alcohol J.
14. Borate of Magnefia and Lime.
1. This fait, which has been lately difeovered native,
is called by mineralogifts cubic quartz. It was analyz¬
ed by Weftrumb in 1788. It is an infipid fait, and is
regularly cryftallized in polyhedrons of 2 2 faces.
The fpecific gravity is 2. if66.
2. It is not altered by expofure to the air, nor is it
599
foluble even in boiling Water. Expofed to a ftrong red Magnefia,
heat, the cryftals lofe their luftre 5 and with a white
heat they decrepitate, and at laft melt into a yellow
coloured glafs.
3. The component parts of this fait are.
Acid, 73.5
Magnefia, 14*6]
Lime, 11.9
£cc.
1381
Compofi-
tion.
100.0
15. Phofphate of Magnefia.
1. This fait maybe obtained by the direft combination Prepara-
of phofphoric acid and carbonate of magnefia ; or, it tion.
may be prepared by mixing together phofphate of foda
and fulphate ot magnefia in folution. In a few hours,
large, tranfparent cryftals are formed in the folution.
2. This fait cryftallizes in fix-fided prifms with un-properties,
equal fides, but it is frequently in the form of powder.
It has a cooling, fweetiftr tafte. The fpecific gravity
is i-5489- ... . 1384
3. It efflorefees in the air, is not very foluble in Aftion of
cold w'ater, and requires about 50 parts of boiling wa- water,
ter for its folution, and part of it cryftallizes on cooling. 1385
When it is heated, it is eafily deprived of its water of Wheat,
cryftallizatiort, and if the heat be moderate, it melts
and falls down into a white powder. With a ftronger
heat, it is melted into glafs.
16. Phofphate of Ammonia and Magnefia.
13S6
1. This triple fait was difeovered by Fourcroy in a Found na*.
calculous concretion, found in the colon of a horfe.1^*
The refults of his experiments on this fubftance have
been confirmed by Berthollet and Vauquelin. 1387
2. It may be prepared artificially, by mixing toge-Prepara-
tber a folution of phofpbate of magnefia with a folu-tl0n*
tion of phofphate of ammonia. j.gg
3. The cryftals are in the prifmatic form, but cannot Properties,
be accurately afeertained. This fait has no tafte. In
the concrete form, it is found in the cavities of animal
bodies, and fometimes it is cryftallized, but moft fre¬
quently lamellated and femitranfparent.
4. It is not changed by the aflion of the air, and is Adtion of
fcarcely foluble in water. When it is heated moder-heat,
ately, it falls to powder. With a ftronger heat it is
deprived of the ammonia, and under the blow-pipe it
melts into a tranfparent globule. It is decompofed by
the fulphuric, nitric, and muriatic acids. ,
The component parts of this fait found in the in- Compofi-
teftine of the horfe are, tion.
Phofphate of ammonia
  magnefia
——— water
33-3
33-3
33*3
100.0
17. Phofphite of Magnefia.
1. This fait may be prepared by dire&ly combin-Preparst*
ing phofphorous acid with magnefia. Or it may be ob-tion.
tained in a purer ftate, and cryftallized, by mixing to¬
gether folutions of phofphiteS of foda or of potafh, and
fulpbate of magnefia, by which means it is obtained in
brilliant milky flakes.
2. This
Co©
Magnefia,
&.C.
1.392
Properties.
*393 ,
Names and
prepara¬
tion.
^ *394
Properties.
*395
Adtion of
water and
heat.
1395
Compofi-
hion.
CHEMISTRY.
2. This fait, which has no fenfible tafte, fometimes
cryftallizes in the form of tetrahedrons. It efflorefces
in the air, and is foluble in 400 parts of cold water.
When expofed to heat, it fuddenly fwells up, and melts
into a glafs. Under the blow-pipe it gives out a phof-
phoric light, and becomes opaque on cooling.
The component parts of this ialt are,
21. Arfeniate of Magneila*
When arfcnic acid is faturated with nsagnefia, a
thick matter forms towards the point of faturation,
which is foluble in excefs of acid j but when it is eva¬
porated, it does not cryftallize. It aflumes the form,
of a jelly. It is decompofed by the alkaline arfeniates.
Magnefia,
See.
Acid 44
Magnefia 20
Water 36
IOO
18. Phofphite of Ammonia and Magnefia.
This fait is formed by the partial decompofition of
phofphite .of ammonia by means of magnefia, or by
mixing together the folutions of the two phofphites.
If the folutions be fufficiently concentrated, the triple
phofphite it readily depofited. It forms cryftals, and
has little folubility in water. Its other properties are
unknown.
19. Carbonate of Magnefia.
1. This fait, which w7as firft diftinguilhed by Dr
Black, has been called mild magnefia, aerated mag-
nefa. It is formed by mixing together fulphate of
magnefia and carbonate of potafh in folutiom Or
it may be obtained by diflblving pure magnefia in w7a-
ter faturated wdth carbonic acid. The fait, as the fo-
lution is evaporated, cryftallizes.
2. The magnefia of commerce which is in the ftate
of powder, or light friable cakes, is not fully faturated
with the acid. But when it is cryftallized by the above
procefles, it is in the form of tranfparent fix-fided
prifms, terminated by a hexagonal plane. This fait
has little tafte. The fpecific gravity is 0.2941.
3. When it is cryftallized, it foon loles its tranfpar-
ency in the air. It is foluble in 48 parts of cold wa¬
ter. Expofed to heat in a crucible, it {lightly decrepi¬
tates, is deprived of its water and acid, and falls down
into a powder. It is decompofed by all the acids. The
component parts of this fait arc, according to
Bergman.
Acid 30
Magnefia 45
Water 25
Fourcroy.
So
25
25
100
100
100
The magnefia of commerce is compofed of
Fourcroy. Kirwan.
Carbonic acid 48 34
Magnefia 40 45
Water 12 21
100 100
20. Carbonate of Ammonia and Magnefia.
This triple fait is prepared by decompofing carbon¬
ate of ammonia by means of magnefia or by preci¬
pitating a folution of carbonate of magnefia by means
of pure ammonia. This fait, however, has not been
particularly examined.
22. Tungftate of Magnefia.
This acid, in combination -with magnefia, forms a fait
which appears in the form of brilliant feales. It is not
altered by expofure to the air, and it is foiuble in w’a-
ter. It is decompofed by acids, and a white pow der is
precipitated.
23. Molybdate of Magnefia. I
24. Chromate of Magnefia. > unknown.
25. Columbate of Magnefia. j
26. Acetate of Magnefia.
This fait is formed by the direft combination of
magnefia with acetic acid. It does not cryftallize, but
a vifeid mafs remains when the folution is evaporated.
It has a fweetifh tafte, leaving afterwards an impref-
fion of bitternefs. The fpecific gravity is 1.378. It
deliquefees in the air, is very foluble in water, and is
decompofed by heat.
27. Oxalate of Magnefia.
This fait is ‘formed by combining oxalic acid with
magnefia, and evaporating the folution. A fait is ob¬
tained in the form of white powder, which is fcarcely
foluble in w7ater. It is decompofed by heat. The
component parts of this fait are
Acid and water 65
Magnefia 35
100
28. Tartrate of Magnefia.'
This compound of tartaric acid and magnefia forms a
fait which is infoluble in water, without an excefs ofacid.
When this is the cafe, it cryftallizes by evaporation.
The cryftals are in the form of hexangular truncated
prifms. It is firft melted, and then decompofed by
heat.
29. Citrate of Magnefia.
This fait is obtained by diffolving carbonate of mag¬
nefia in citric acid. From the thick folution of this
fait, there is no cryftallization 5 but after fome days,
by a flight agitation, it aflumes the form of a white
opaque mafs, which remains foft, as it feparates from
the edges of the veffel. The component parts of this
fait are
Acid 66.66
Magnefia 33.34
This is a
ter.
100.00 *. * FounKp
vii. 20S.
30. Malate of Magnefia.
deliquefeent fait, and very foluble in wa-
31. Gallate
£
C H E M I
Magnefia,
See.
31. Gallate of Magnefia.
» Magnefia boiled with an infufion of nut galls, affords
a clear liquid, which affumes a green colour. This is
foluble in an excefs of acid.
32. Benzoate of Magnefia.
The combination of benzoic acid with magnefia
affords plumofe cryftals which are eafily foluble in wa¬
ter. This fait has a bitter tafte.
33. Succinate of Magnefia.
The fait which is formed by the combination of fuc-
cinic acid and magnefia, does not cryftallize. It is a
white glutinous mafs which is deliquefeent in the air.
34. Saccolate of Magnefia.
This fait is infoluble in water.
35. Camphorate of Magnefia.
Prepara- 1 • This fait is formed by mixing carbonate of mag-
tion. nefia with water, and adding cryftallized camphoric
acid. A flight effervefcence takes place. The tem¬
perature fhould be increafed, to drive off the carbonic
acid. The folution is filtered while it is hot, and eva¬
porated to drynefs. The mafs is diffolved in difiilled
water, filtrated and evaporated by a gentle heat, till
a pellicle appears on the furface. By cooling there
are depofited fmall plates, which are heaped upon each
g other.
Properties. 2* This fait, which does not cryftallize, is white
and opaque, and has a bitter tafte. In the air it is
flightly efflorefeent. It is not very foluble in water.
Boiling water diffolves a little, but it is precipitated in
cooling. When it is thrown on red-hot coals, the
acid is volatilized, and pure magnefia remains behind.
By the attion of the blow-pipe it gives out a bluilh
flame. It is decompofed by fulphuric, nitric, and mu-
*An«.d< riatic acids *.
Cbim. xxvii. , „ , r ^ r
p. 27. 36. Suberate ot Magneha.
The compound of fuberic acid and magnefia is in the
form of powder. It has a bitter tafte, is deliquefeent
in the air, and foluble in water. It reddens the tinc¬
ture of turnfole. Expofed to heat, it fwells up and
melts. By the a&ion of the blow-pipe, the fait is de¬
compofed, the acid Is driven off, and pure magnefia
remains behind. The fulphuric, nitric, and muriatic
acids, decompofe it. It is alfo decompofed by the al-
f nu. xxiii. kalies, barytes, and lime f.
56, 37. Mellate of Magnefia.
Unknown.
38. La&ate of Magnefia.
A fait in fmall deliquefeent cryftals.
39. Prufliate of Magnefia.
This fait may be prepared by direflly combining
Vol.V. Part II.
S T R Y. 601
pruflic acid with pure magnefia j but the magnefia is Alumina,
precipitated when the folution is expofed to the air. It, ^c' ,
is alfo decompofed by the alkalies and lime.
Sect. V. Of Alvmina and its Combinations*
1399
1. Alumina, which is now employed to fignify one Hiftory.
of the Ample earths, is derived from the w7ord alum,
of which this earth forms a conftituent part, and
from which it is obtained in greateft purity. It was
formerly denominated argil and argillaceous earth;
but thefe names being expreflive of mixtures of differ¬
ent earths, have been properly rejefted. Pott and
Margraaf were the firft who diftinguiftied this earth
from the calcareous earth or lime, and proved that
this latter earth could not be obtained from it by cal¬
cination. In the year 1739 Hellot {hewed, that the
bafis of alum, feparated from this fait by an alkali, was
pure argil, or alumina. In 1758 and 1762 Macquer
examined this earth, and detailed its charafteriftic pro¬
perties. Thefe wrere afterwards farther elucidated and
confirmed by the experiments and refearchesof Bergman
and Scheele, fo that the nature and chara&ers of this
earth were completely developed, and it was univerfal-
ly admitted as diftinft from all others hitherto known. r40»
2. Although alumina exifts in great abundance in Prepara-
nature, yet it is rarely found uncombined, or in a ftatetlon-
of perfe£l purity. It may be obtained pure by the fol¬
lowing procefs.
Diffolve a quantity of common alum in water, and add
to the folution, a folution of potafh or carbonate of potafh,
or what is fuppofed to be ftill better, liquid ammonia.
An abundant white precipitate is immediately formed.
Continue the addition of the alkali as long as any pre¬
cipitate appears. When the whole of the precipitate
has collefted at the bottom of the veffel, pour off the
fluid part, and walh the precipitate repeatedly with
large quantities of water, to free it from all faline mat¬
ters which it may have retained. Dry the precipitate
in a moderate heat, and the fubftance thus obtained is
alumina in a ftate of tolerable purity. If this precipi¬
tate retain any portion of fulphuric acid, it may be fe¬
parated by adding muriatic acid in fmall quantities at
a time, till the whole is diffolved. Evaporate the
folution till a drop of it, when fuffered to cool on
a plate of glafs, yields minute cryftals. Then fet by
the folution till it cool, and cryftals wull be depofited.
Let thefe cryftals be removed by pouring off the fluid,
and continue the evaporation till no more cryftals are
formed. In this way the alum which the earth retain¬
ed, may be feparated. The liquid which remains is to
be mixed wflth ammonia as long as any precipitate ap¬
pears. This precipitate, well waftied and dried, is
pure alumina. I40I
3. The alumina obtained by this procefs, is either in Properties
the form of friable fragments, or of very fine white
powder, foft to the touch, and infipid to the tafte. It
has a peculiar odour, which is diftinguiftied by the name
of earthy fmell, and is only perceptible when it is breath¬
ed upon, or moiftened (o). It adheres to the tongue in
4 G confequence
(o) This fmell, however, as it has been juftly obferved by Sauffure, is owing to the oxide of iron with
which the alumina in its ordinary ftate of purification, is contaminated j for when it is perfectly pure, and no
traces
A
602
Alumina,
&cc.
1402
Spongy
alumina.
CHEMISTRY.
* your, dt
JPbyJlque,
lii. p. 290.
1403
Gelatinous.
1404
Action of
heat.
^14°S
Of water.
1405
©f carbone.
1407
Of acids.
confequence of its rapidly abforbing moiflure.
fpecific gravity is 2.
4. Sauflure has obferved, that alumina exhibits two
different appearances, according to the quantity of
jvater which has been employed in the folution of the
aluminous fait. If the quantity of water does not ex¬
ceed what is neceffary for the folution of the fait, we
obtain a light friable white earth, which is very fpon-
gy, and adheres to the tongue. This he calls fpongy
alumina. But when the fait is diffolved in a large
quantity of water, w7e obtain, after drying the preci¬
pitate in the fame temperature, a yellowilh brittle
tranfparent mafs, which fplits into fmall fragments
when held in the hand like folid fulphur. It has 4
fmooth conchoidal fracture, no earthy appearance,
does not adhere to the tongue, and does not fwell up
when put into w^ater. It occupies 10 or 12 times lefs
volume than in the fpongy ftate, and has fome appear¬
ance to gum arabic, or a dried jelly. This he di-
Ifinguifhes by the name of gelatinous alumina *.
5. Alumina undergoes no change by being expofed
to light. When it is expofed to heat, it is diminifhed
in bulk, in confequence of being deprived of the wa¬
ter with which it is combined. Accordingly, Sauf-
fure has obferved, that the fpongy alumina expofed to
the fame temperature, lofes a greater quantity of moif-
ture than the gelatinous alumina. The former, when
expofed to a red heat, lofes 0.58 parts of its weight;
but the latter only 0.43 parts. When they are both
expofed to a very ftrong heat, the fpongy alumina is
deprived of no more w'ater than what it gives out with
a red heat, while the gelatinous parts with only 0.4825.
On this property of the contraction of bulk of alumi¬
na when expofed to heat, depends the principle of the
thermometer, or pyrometer, of Wedgwood, of w’hich
we lhall immediately give a Ihort defcription.
When alumina is expofed to a very Itrong heat fud-
denly applied, as by means of the blow-pipe, wuth a
Itream of oxygen gas, it is fufceptible of a kind of
fufion ; and when it is cooled, it appears under the
form of an enamel, of a greenifh colour, and fo hard,
as to cut glafs.
6. Alumina is not foluble in water, but it abforbs
and retains that fluid in cdnfiderable quantity. With
a greater quantity of water it is diffufed in it, and may
be formed into a pafte, in which ftate it is moulded
with great facility into any form.
7. There is no aftion between alumina and oxygen,
azote, hydrogen, or phofphorus j and very little be¬
tween it and fulphur, except when they are in a ftate
of minute divifion, or in combination with fome other
fubftances. Carbone combines with alumina, of which
there are many natural compounds, among the clafs
of bituminous foffils ; but even in thefe compounds,
the carbone and alumina are mixed with other earths,
and with the oxide of iron.
8. Alumina enters into combination with almoft all
the acids, and forms falts which are more or lefs folu¬
ble, and fufceptibk of cryftallization. Some are info-
luble in water, and others require an excefs of acid.
The 9. The order of its affinity for the acids, is the fol- Alumina,
lowing.
Sulphuric acid,
Nitric,
Muriatic,
Oxalic,
Arfenic,
Fluoric,
Tartaric,
Succinic,
Saclaflic,
Citric,
Phofphoric,
La£Hc,
Benzoic,
Acetic,
Boracic,
Sulphurous,
Carbonic,
Pruffic.
6tc.
Y'
1408
AffiaitieS^
IO.
Alumina combines with the fixed alkalies, of alkalies
When they are heated together, an opaque mafs,
which has little coherence, is formed. Fixed alkali
diffolved in water, with the affiftance of heat, has the
property of diffolving alumina ; but from this folution
it may be precipitated by means of an acid, and then
it is obtained in great purity. Liquid ammonia alfo
holds a fmall quantity of alumina in folution, if it has
been recently precipitated.
11. Alumina enters into combination with many of Qf earth?
the earths, and particularly with lime and filica. Thefe
compounds form the chief bafts of all kinds of pottery
and porcelain. Alumina combines with lime, and en¬
ters into fufion with it by means of heat. A com¬
pound is alfo formed with alumina and barytes, or
ftrontites, by expofing them together in a crucible to
a ftrong heat j or, by boiling them together in water.
Magnefia and alumina alone, do not enter into combi¬
nation by means of the ftrongeft heat j but a porcelain
is obtained from a mixture of lime, magnefia, and alu¬
mina. But in the proportions that are employed, it is
neceffary that the alumina be greateft. The following
table thews the refults of experiments on thefe earths in
different proportions *.
S}
Alumina,
Lime, 2 [- A porcelain.
Magnefia,
Alumina,
Magnefia, 2 A porcelain.
Lime,
Alumina, 3 T
Magnefia, 3 > Porous porcelain.
Lime, 1J
Alumina,
Magnefia,
Lime,
* Kirivan,
Mineral,
i. p. 61.
37
3 > Porous porcelain.
2J
Alumina,
traces of oxide of iron can be dete&ed, it has no perceptible fmell. To alumina which was perfe&ly inodor¬
ous, he communicated this fmell, by triturating it with oxide of iron. ’Journal de Pbyjique^ lii. p, 287.
C H E M
Alumina, 3
Lime, 2
Magnefia, 2
Ufes. 12. This is one of the moft important of the earths,
on account of the variety of purpofes to which it is ap¬
plied. It forms the bales of all kinds of earthen ware,
from the coarfeft brick to the fineft china. It is alfo
chiefly employed in the pots or crucibles which are ex-
pofed to very ftrong heat, as in glafs manufafture and
call; iron. It is employed alfo in dyeing and calico
printing, and in the cleaning or fcouring of woollen
fluffs. It has been applied to a valuable ufe by the
late Mr Wedgwood, in the conftruftion of an inflru-
ment capable of afcertaining high degrees of tempe¬
rature, to which the common thermometer cannot
14!a reach.
Wedg- 13. This inftrument is conftru&ed on the principle
wood’s py- of the contraftion of pure clay, when it is expofed to
rometer. heat. Mr Wedgwood took a very pure clay, and
formed it into fmall fhort cylinders, which were made
exa£tly of the fame fize. They are then baked in a
low red heat, to expel the w'hole of the air and moi-
flure which adhere to the clay. The cylinders are
thus prepared for the meafurement of ftrong heats.
For this purpofe, one of the cylinders is introduced
between two rulers, to which a fcale is attached, and
its bulk is exa£tly meafured. It is then introduced
into the furnace whofe heat is to be tried, and the
temperature is to be eftimated according to the dimi¬
nution of bulk which the cylinder has fuftained. The
quantity of contraction is meafured by means of two
metallic rulers, which are fixed upon a plate. Thefe
rulers are 24 inches in length, and are divided into
240 parts. The diftance between the rulers at the up¬
per extremity of the fcale is 0.5 of an inch, and at the
lower extremity 0.3 of an inch. The fize of the clay
cylinder, before it is introduced into the furnace,
nearly fits the upper part of the fcale; or at leaft the
degree at which it Hands, before it is introduced into
the furnace, is marked. After being heated, the clay
cylinder is again applied to the fcale, and the diminu¬
tion of bulk is meafured by the diftance at which it
Hands between the rulers from the top of the fcale, or
from the degree at which it flood before it was expofed
1413 t0 the heat*
Scale of it. Mr Wedgwood connefted the fcale of his pyrome¬
ter with Fahrenheit’s thermometer. The firfl: degree
of his fcale which marks a red heat, correfponds to
the 9470 Fahrenheit ; but to make this inftrument bet¬
ter underflood, we may ilate a. few of the correfpond-
sng degrees of the two inftruments.
Wedgwood. Fahrenheit.
Red heat,
Fine filver melts
Fine gold melts
Welding heat of iron
Call iron melts
Greateft heat in an air furnace
eight inches Iquare
Extremity of the fcale, or highefl
temperature obferved
This inftrument has been of confiderable importance
in feme arts and manufaflures, and it is undoubtedly
—
4717
5237
13427
17977
21877
32277
Porcelain.
Alumina,
See.
1411
I S T R Y.
603
*4*4
fitted to give fome information concerning thofe in- Alumina,
tenfe heats which can be meafured by no other inftru- &c*
ment which has yet been Contrived. But as the fame
kind of clay cannot always be obtained, and as it is
probable that the contractions of the cylinders are not
proportional to the temperatures, their eftimation by
this inftrument can only be confidered as an approxi¬
mation to certainty.
I. Compounds of Alumina with Acids.
1. Sulphate of Alumina.
1. This is a compound of fulphuric acid and alumi-Prepara-
na. It may be formed by the direft combination oftion*
the acid with the earth. But in the preparation of
this fait, the earth and the acid muft be in a ftate of
purity, and muft be faturated with each other. The .
folution is then evaporated to drynefs j the fait is
again diflblved in diftilied water, and evaporated flowly
till it cryftallizes. 141;
2. The cryftals of this fait are in the form of thin Propertied
plates, foft and pliant, with a brilliant pearly luftre,
and of an aftringent tafte. It is not altered by expo-
fure to the air $ it is very foluble in water, but it does
not cryftallize readily. When it is heated, it is infu- Aftion of
fible j but by long calcination, it dries and falls dowm ^eat» ^c*
to powder. At a high temperature it is decompofed,
and the acid is driven off.
3. The fulphuric acid readily combines with this
fait, and forms with it an acidulous fulphate of alu¬
mina. This fait has a more acid tafte than the for¬
mer } it cryftallizes with more difficulty, and the cry¬
ftals have more brilliancy. It reddens vegetable blues,
and frequently affumes the form of a thick gelatinous
mafs.
4. All the alkaline and earthy bafes, except filica
and zirconia, decompofe either of thefe twro falts.
The faturated fulphate of alumina, according to Berg¬
man, is compofed of
„ r4T7
Sulphuric acid, 50 Compoli-
Alumina, 50
tion.
, IOO
2. Acidulous Sulphate of Alumina and Potaffi, or
Alum.
r4lS
1. The alum of commerce, now of fuch extenfive Hiftory.
utility in many of the arts and manufadlures, wTas im¬
ported into Europe from Afia, previous to the 15th
century, during which it was begun to be manufac¬
tured in Italy. Alum works were eredled in Spain
and Germany in the 16th century; and towards the
end of it, a manufactory of this fait was eftabliftied in
Yorklhire in England. But the true nature of alum
has been only of late underftood. It is to the experi¬
ments and refearches of Vauquelin, that we are in¬
debted for the knowledge of its component parts.
2. Alum is generally obtained by expofing to the Prepara»
weather for fome time, aluminous ffiiftus, or what are tlon‘
called aluminous ores, which are natural productions,
fometimes found in the neighbourhood of volcanoes,
and fometimes, as in Britain, dug out of coal mines
which abound with pyrites or fulphuret of iron. When
thefe fubftances, which are alfo mixed with a confider-
4 G 2 able
604
Alumina,
See.
1420
Properties.
r 1421
Adtion of
water and
heat.
1422
Varieties.
14*3
Competi¬
tion.
C H E M I
able proportion of clay, are expofed to air and moi-
fture, the fulphur combines with the oxygen of the
air, or with that of the water, by decompofing it, and
is thus converted into fulphuric acid. This combines
with the alumina, and thus there is formed a fulphate
of alumina. The fait thus formed, is diffolved in wa¬
ter, and mull be purified by repeated boilings and cry-
ftallizations. This aluminous fchiftus is generally
mixed with a confiderable proportion of lulphate of
iron. From this it is to be leparated during the pro-
cefs, and the potalh or ammonia which is necellary to
conflitute the triple fait, muft be added. Even be¬
fore the component parts of alum were difeovered, the
addition of potalh or ammonia was found to be necef-
fary to complete the procefs. This was well known
to the manufacturers, who luppofed that it was necel-
fary to take up a quantity of acid, which being in ex-
cefs, prevente'd the granulation, as it was called, or
the cryftallization of the alum.
3. Alum cryltallizes in regular oCtahedrons 5 but
this form is fubjeCt to confiderable variety, according
to the difference of proportion which is found to take
place among its component parts. I he primitive form
of the cryftal is the regular o&ahedron, and the inte¬
grant molecule the regular tetrahedron. It has a very
aftringent, ftyptic, and fomewhat fweetilh tafte. It
ufually reddens vegetable blues. The fpecific gravity
is 1.7109.
4. It is little changed by expofure to the air. By
long conta£l there is a flight efflorefcence on the fur-
face. Alum is foluble in 16 or 20 parts of cold wa¬
ter. Boiling water diffolves a greater proportion.
When expofed to heat, it melts in its water of cryfial-
lization. It then fwells up, enlarges in volume, and
there remains behind a light, porous, dry mafs, w-hich
has a {harp acid tafte, and reddens more ftrongly ve¬
getable blues. In this ftate it is called burnt or cal¬
cined alum. When it is expofed to a ftronger heat, the
acid is driven off.
5. According to the experiments of Vauquelin,
there are three kinds or varieties of alum, which, al¬
though they poffefs nearly the fame properties, have
different co'nftituent parts, or different proportions of
the fame conftituents. The firft is fulphate of alumina
and potafh with an excefs of acid ; which indeed is ne-
ceffary to conftitute alum. The fecond confifts of alu¬
mina and ammonia, alfo with an excefs of acid. The
third variety which is moil frequently found among
the alum of commerce, is a mixture of both. It con¬
tains both potafh and ammonia. When an additional
quantity of potafh is added, the alum cryftallizes, not
in its ufual form, but in the form of cubes, and hence
it has been denominated cubic alum. If a ftill greater
quantity of potafh be added, the cryftallization is near¬
ly interrupted } and it then appears in the form of
flakes.
The component parts of alum, are according to
V auqueiin.
Sulphate of alumina, 49
  .. ■ ■ ■ Potafh, 7
Water, 44
Kirwan.
Acid, 17.66
Bafe, 12.00
Water, 70.34
*4*4
Aftion of
charcoal.
10®
100.00
6. The three varieties of alum are nearly decompo-
s T R Y.
fed in the fame way, by combuftible fubftances. If Alumina,
alum be expofed to a moderate heat with charcoal, it
is converted into the ftate of neutral fait, becaufe the
charcoal afts on the excefs of acid, before it can effea
the decompofition of the fait ; but when it is ftrongly
heated, there is formed with the fulphate of alumina
and potafh, a black fubftance, w’hich fpontaneoufly takes
fire in the air. This fubftance has been diftinguifhed
by the name of pyrophorus, and it is called Homberg's
pyrophorus, becaufe it was difeovered by that che-
inift- _ . . 1425
Pyrophorus is prepared by mixing together three Pyrophorujv
parts of alum, and one of flower or fugar, in an iron
ladle, and expofing the mixture to heat till it ceafes
to fwell, and becomes black. It is then to be redu¬
ced to powder, put into a glafs phial, and again ex¬
pofed to heat, till a blue flame proceeds, from the
mouth of the phial. After it burns for a minute, it is
allowed to cool, and muft be kept in a wrell-clofed
bottle. 14*5
7. The pyrophorus thus formed, contains a hydro-Properties,
genated fulphuret of potafh and alumina, mixed with
charcoal in a ftate of minute divifion. It kindles more
readily in humid than in dry air. The oxygen gas of
the atmofpheric air is abforbed. Part is converted into
carbonic acid, and part combines with the fulphur,
and forms fulphuric acid j fo that when the pyropho¬
rus is burnt, it no longer contains the hydrogenated
fulphuret as before, but fulphate of alumina and pot¬
afh j not in the ftate of alum, becaufe it has been de¬
prived of the excefs of acid, which gives it its peculiar
character.
8. Pyrophorus gives out a very fetid odour, when
it is throwm into water, and leaves behind a fulphu¬
ret of potafh, and of hydrogenated alumina.. It is „ Fourcroj,
inflamed by nitrous gas, and by oxymuriatic acid iij. p. 59, '
gas#* T . *4*7
9. The ufes of alum are very numerous. It is em- ufes of
ployed in medicine as an aftringent and ftyptic. It is alum,
employed in the arts of bleaching, of tanning, dyeing,
calico-printing, and others. It is fometimes ufed in
preferving animal matters from putrefaffion, and it
might be employed for the purpofe of fecuring wood
from catching fire. # i42g
Sulphate of alumina and potajh.^-i. If a folution ofprepara.
cryftallized alum be boiled with a folution of pure a- tion.
lumina, the faturated fulphate of alumina and potafh
is formed. The excefs of acid, it is. obvious, in this
procefs, enters into combination with the alumina.
The alum, as the earth is added, is gradually precipi¬
tated in the folution, in the form of a white powder.
2. This fait, faturated with alumina, never aflumes proper^e3,
any regular form. It has no tafte, is not changed by
expofure to the air, is not foluble in w’ater, and when
it is expofed to heat, it is not altered, except at a very
high temperature. This fait is lefs eafily decompofed
than any of the other varieties of fulphate of alumina.
By the aftion of fome of the acids it is converted into
alum, which is owing to the acid combining with the
additional portion of alumina, that faturated the ex¬
cefs of acid exifting in the alum. This fait has been
applied to no ufe.
3. Sulphite of Alumina. I43D.
I, The compound of fulphurous acid and alumina^ePaira“
1431
Properties
C H E M
Alumina, is prepared by paffing fulpburous acid gas into water
&c- in which pure alumina is mixed or fufpended. .
1 ' 2, The fulphite of alumina thus formed, is in the
ftate of a white, foft powder, which has at firft an
earthy tafte, and becomes afterwards fulphureous.
When it is expofed to the air, for a long time, it is
converted into the fulphate of alumina, and more ra¬
pidly if it be combined with an >'xcefs of fulphurous
acid. It is infoluble in water. Expofed to heat, the
acid is driven off, and partially decompofed, for there
remains behind a fmall quantity of fulphur. The com¬
ponent parts of this fait, are
1432
Compofi-
tion.
*433
Prepara¬
tion.
*434
Properties.
Sulphurous acid 32
Alumina 44
Water 24
100
4. Nitrate of Alumina.
1. This fait was formerly known under the names of
nitre of argil, and nitrous alum. It is formed by the
dire£l combination of the nitric acid with alumina.
It has been found impoffible to neutralize the acid j
and it cannot be obtained cryllallized, excepting in
the form of thin plates, and often only in a gelatinous
mafs.
2. This fait has an auftere and acid tafte.. The fpe-
cific gravity is 1.645. It is deliquefcent in the air,
and extremely foluble in water. When it is heated,
the acid is driven off, and the pure earth remains be¬
hind. It is readily decompofed by the fulphuric acid,
which disengages the nitric acid ; and by the muriatic
acid, which is converted into the oxymuriatic acid.
5. Nitrite of Alumina.
This fait is unknown.
*435
Prepara¬
tion.
1436
Properties.
* Phil.
Tranf.
1802, p.
149.
6. Muriate of Alumina.
1. This fait, which is a compound of muriatic acid
and alumina, is formed by the direft combination of
the acid with the earth •, but it is never neutralized^
The acid is always in excefs.
2. This fait is rarely cryftallized, but moft frequently
m the form of white powder, or in that of a gelatinous
mafs. It has an aftringent, acid, and ftiarp tafte. It
reddens the tinfture of turnfole and of violets. It js
extremely deliquefcent in the air, and very foluble in
water. When it is expofed to heat it melts, and is de¬
compofed. The acid is feparated, and the pure alu¬
mina remains behind. It is decompofed in the fame
way as the other muriates.
7. Hyperoxymuriate of Alumina.
r. This fait is prepared by paffing oxymuriatic acid
gas through water in which newly precipitated alumina
is fufpended. The alumina difappears, and when ful¬
phuric acid is poured into the folution, a ftrong fmell
of hyperoxymuriatic acid gas is perceived.
2. This fait is deliquefcent, and it is foluble in alco¬
hol. Mr Chenevix could not afcertain the proportion
of its principles *.
8. Fluate of Alumina.
The combination of fluoric acid and alumina, affords
a fait which cannot be cryftallized, but which is in
Y. 6oj
It has always an excefs of acid, Alumina,
and an aftringent tafte. It is decompofed by all the c*
earthy and alkaline bafes. With the latter it forms
triple falls.
I S T R
the form of a jelly
9. Borate of Alumina.
It is extremely difficult to form a compound of alu¬
mina and boracic acid by diredf combination. This
fait may be formed by mixing together a folution of
borate of foda, with a folution of fulphate of alumina.
Its properties have not been examined.
10. Phofphate of Alumina.
This fait is little known. By faturating phofpho-
ric acid with alumina, a white powdery mafs is obtain¬
ed, which has little tafte, except there be an excefs of
acid, and then it feems to form an acidulous fait. It
melts under the blow-pipe into a tranfparent globule,,
without decompofttion. It is decompoied by the alka¬
lies, fome of the earths, and the acids.
11. Phofphite of Alumina.
1. This fait is formed by the dire& combination of
phofphorous acid with alumina. The folution is to
be evaporated to a proper confiftence.
2. The phofphite of alumina does not cryftallize,
but forms a thick, vifcid, gummy mafs, which becomes
dry and folid in the air. It has an aftringent tafte, is
very foluble in water, fwells up w'hen it is heated,
and gives out a phofphoric light. It is decompoied
by all the alkaline and earthy bafes.
12. Carbonate of Alumina.
1437
Little is known of the combination of carbonic acid This com-
and alumina. Bergman had obferved, when alum was pound little-
precipitated by an alkaline carbonate, that very little or nown’
no effervefcence took place $ he therefore concluded,,
that the carbonic acid, not being driven off, muft have
combined with the alumina which w'as precipitated.
And befides he found, that the liquid contained a por¬
tion of carbonate of alumina,, which is depoftted fome
hours or fome days afterwards by the evaporation of the
carbonic acid, wdiich held it in folution.
Common clay, which is a mixture of alumina and
filica, contains a certain portion of carbonic acid,
which is difengaged by the application of ftrong heat.
He obtained from one fpecies of clay, feveral times its
volume of this acid, mixed with a fmall portion of hy¬
drogen gas. It is owing to the fame combination of car¬
bonic acid, that clays, treated with acids, effervelce,
without containing any carbonate of lime.
According to Sauffure, alumina is diflolved in water,^,jie ^
which is faturated with carbonic acid 3 but when the combined
folution is expofed to the air, it is decompofed. with water*
33. Arfeniate of Alumina.
This fait is formed by diffolving alumina in arfenic
acid, and evaporating the folution to drynefs. A
thick mafs is thus obtained, which is infoluble in wTa-
ter. It is decompofed by the fulphuric, nitric, and
muriatic acids, as well as by the earthy and alkaline
bafes.
14. Tungftate of Alumina.
This fait has not been examined.
15 Molybdate
6o6
CHEMISTRY.
Alumina,
&c.
1439
Properties.
1440
Compoli-
tion.
* PM.
Tranf.
1803, p.
244.
*44*
Prepara-
tion.
*5. Molybdate of Alumina.'!
» 16. Chromate of Alumina. > unknown.
17. Columbate of Alumina, j
18. Acetate of Alumina.
The acetic acid enters into combination with alu¬
mina, and forms with it fmall, needle-fhaped cryftals,
which are foft, deliquefcent, and have an aftringent
tafte. The fpecific gravity of this fait is 1.245. Its
other properties are unknown.
I
19. Oxalate of Alumina.
Oxalic acid very readily combines with alumina.
When the folution is evaporated, a yellowifh, foft,
tranfparent mafs is obtained, but it does not cryftal-
lize. This fait has an aftringent tafte, is deliquefcent,
and reddens the tinfture of turnfole. When it is heat¬
ed, it fwells up, is deprived of its acid, and the alumina
remains behind, flightly coloured. It is decompofed
by the ftronger acids.
The component parts of this fait are,
Acid and water 56
Alumina - 44
100
20. Tartrate of Alumina.
Alumina enters into combination with tartaric acid,
and forms an uncryftallized, gelatinous mafs, which
has an aftringent tafte, is not deliquefcent in the air,
but is foluble in water.
21. Citrate of Alumina.
The properties of this fait have not been examined.
22. Malate of Alumina.
When malic acid is added to a folution, containing
alumina, a precipitate is formed, which is fcarcely fo¬
luble in water.
23. Gallate of Alumina.
If pure alumina be added to a folution of nut-galls,
an infoluble compound is formed with the tannin and
extraft. The liquid remained clear and white, and it
afforded by evaporation, fmall cryftals, wdiich are gal¬
late of alumina with excels of acid *.
24. Benzoate of Alumina.
The compound of benzoic acid and alumina affords
a fait, which cryftallizes in an arborefcent form. It
has a bitter tafte, is deliquefcent in the air, foluble in
water, is decompofed by the aftion of heat, and even
by moft of the vegetable acids.
25. Succinate of Alumina.
The compound of fuccinic acid and alumina affords
falls w’hich cryftallize in the form of prifms, and are
eafily decompofed by heat.
26. Saccolate of Alumina.
This compound of faclaftic acid and alumina forms
a fait ’which is infoluble in water.
27. Camphorate of Alumina,
i. The compound of camphoric acid and alumina
1442
Properties.
* Ann. dt
Chim. xxvii.
P- 34*
M43
Properties.
is formed by precipitating alumina by means of ammo-Silica, See,
nia, walking the precipitate, and diluting it with di- v*—““
ftilled water. Cryftals of camphoric acid are then to
be added. The mixture is to be heated, filtered, and
evaporated.
2. A white powder is thus obtained, which has a
bitter, acid, and aftringent tafte. It reddens vege¬
table blues. This fait is fcarcely altered by expofure
to the air. Water diffolves about ^-5- part of its
weight. Boiling water diffolves it moie readily; but
on cooling, a precipitate is formed. When it is ex-
pofed to heat, it fwells up, and the acid is volatilized.
By the aftion of the blow-pipe, a blue flame is produ¬
ced, the fait is decompofed, and the pure alumina re¬
mains behind. This fait is decompofed by the mineral
acids, and even by fome of the vegetable acids. It
is alfo decompofed by the nitrates of lime and ba¬
rytes
28. Suberate of Alumina.
The compound of fuberic acid and alumina may be
formed by evaporating the folution with a very mode¬
rate heat, in a large open veffel. This fait does not
cryftallize ; but the dried matter which is obtained, is
tranfparent, of a yellowilh colour, and has a ftyp-
tic, bitterilh tafte. When too much heat is employed,
the fait melts and blackens. It reddens the tinfture
of turnfole, and is flightly deliquefcent in the air. Ex-
pofed to the a£tion of the blow-pipe, the acid is volati¬
lized and decompofed, and the alumina remains be¬
hind. It is decompofed by the mineral acids, the earths,
and the alkalies f. f xxjn
P- 56.
29. Mellate of Alumina.
The properties of this fait are unknown.
30. La&ate of Alumina.
This is a deliquefcent fait.
Sect. VI. Of Silica and its Combinations.
1. Silica has been diftinguifhed by the names ofHiftory!
filiceous earth, or quartzy earth, becaufe it is obtained
from flex, or flint, and from the ftone called quarts!,.
This earth exifts in great abundance in nature, and it
conftitutes the bafes of fome of the hardeft ftones of
which the nucleus of the globe confifts; and, on account
of its great abundance, it has been regarded as the pri¬
mitive or elementary earth, the bafe of all the other
earths. Silica forms one of the conftituent parts of
moft ftony bodies ; but it exifts in greateft abundance in
agates, jafper, flints, quartz, and rock cryftal; in the
latter it exifts nearly in a ftate of purity.
2. But to obtain it perfettly pure, a quantity ofp^*44.5
quartz or rock cryftal may be expofed to a red heat. tion.
When it is taken from the fire, and while it is yet hot,
it is fuddenly immerfed in cold water. It is then to be
reduced to powder; and, if tranfparent rock cryftal
has been employed, it is then in a ftate of tolerable
purity. To have it perfe&ly pure, mix one part of the
pounded ftone, with three parts of potafli, and expofe
them in a crucible to heat, which is fufficient for the
fufion of the mixture. The mafs thus obtained is fo¬
luble in water. Add a fufficient quantity of water
for its folution, and drop in muriatic acid, as long aS
there
C H E M
Let this be repeatedly wafh-
The fubftance thus obtained
144?
Properties.
1447
Aftion of
heat, Sec.
144S
Cryftals.
Silica, Sec. there is any precipitate.
' ed with water, and dried,
is pure filica.
3. It is in the form of a very fine white powder,
which-has neither tafte nor fmell. The particles are
rough and harfir to the feel, as when they are rubbed
between the fingers, or touched with the tongue. The
fpecific gravity is 2.66.
4. Light has no action on filica j and it is one of the
peculiar characters of this earth, that it refifts, un¬
changed, the greateft degree of heat.
5. There is no aCtion between filica and oxygen,
azote or hydrogen, nor is it changed by expofure to
the air. It is not nCted upon by carbone, phofphorus,
or fulphur. It is infoluble in water 5 but in a ftate of
minute divifion, it abforbs a confiderable portion, and
forms with this liquid, a tranfparent jelly. When it
is expofed to the air, the whole of the moifture is eva¬
porated.
6. Silica is frequently found in nature in the cryftal-
lizred form, and then it is diftinguifhed by the name
of rock cryjlal. It is moll commonly in hex¬
agonal prilrns, terminated by hexagonal pyramids.
Cryltals of filica have alfo been formed artificially. In
a folution of filica in fluoric acid which had remained
at reft for twro years, Bergman found cryftals, fome of
which were cubes, and fome had truncated angles, at
the bottom of the veflel. Cryftals of filica have alfo
been formed, by diluting largely with water, the com¬
bination of filica and potaih, and allowing it to remain
for a long time. Profeflbr Seigling of Erfurt obtained
cryftals from a folution which had been kept eight
years in a glafs veffel. A cruft was formed on the
top, compofed of carbonate of potaih and cryftallized
filica. The cryftals of the latter were in the form of
tetrahedral pyramids, perfe&ly tranfparent, and fo hard
as to ftrike fire with fteel.
7. Silica is only afted on by,a very few of the acids.
Thefe are, the phofphoric and boracic, which combine
with it by fufion, and the fluoric, which dilfolves filica
either in the gafeous or liquid ftate. When filica is
held in folution in water by means of an alkali, it is al¬
fo diffolved by the muriatic acid.
8. The alkalies have a very powerful a£tion on this
earth. In the preparation of the pure earth, it was
combined with potaih by means of fufion. This com¬
pound is different in its nature and properties, accord¬
ing to the proportions of the filica and the alkali.
Two or three parts of potaih with one of filica, form
a compound which is deliquefcent in the air, and fo-
lublein water. This was formerly diftinguilhed by the
name liquor Jilicum, or liquor of flints. It is now called
(iiicated alkali. When this folution is long expofed to
the air, the earth is depofited in a flaky gelatinous
form. It is decompofed by acids, which combine
with the alkali, and the pure earth falls to the bottom
in the ftate of fine powder. When the folution is
largely diluted with water, and if a greater quantity
of the acid be added than is fufficient to faturate the
alkali, the filica remains in folution. This is particu¬
larly the cafe when the muriatic acid is employed;
but when the filica is in greater proportion, a com¬
pound is formed which is polfelfed of very different
properties. The fubftance thus obtained is glafs.
9. This earth alfo eiders into combination with
1449
Action of
Of adds.
*45°
Of alkalies.
I S T R Y. 607
fome of the earths. If to a folution of the liquor of Silica, Sec.
flints, lime water be added, a precipitate is formed,
which is found to be a compound of filica and lime. I453
Silica alfo combines with lime by means of heat, and0fearths’
in certain proportions a glafs is formed.
The following table, drawn up by Mr Kirv^an, ex¬
hibits the elfefts of heat on thefe earths in different
proportions *. * Mineral*
i. p. 55.
Proportions.
50 Lime
50 Silica
80 Silica
20 Lime
80 Lime
20 Silica
• dgw.
kffed.
150°
Melted into a mafs betwe<
porcelain and enamel, of a
white colour, femitranfparent at
the edges, and which gave fee¬
ble fparks with fteel.
156°
Not melted, but formed a
brittle mafs.
Formed a yellowiflr-white,
loofe powder.
10. Silica enters into combination with baryte
The following table will fhewT the effect of different
proportions of thefe earths, as they were afeertained
by Mr Kirw'an f. \ Hid. 57,
Proporoons.
80 Silica
20 Barytes
75 Silica
20 Barytes
66 Silica
33 Barytes
50 Silica
50 Barytes
80 Barytes
20 Silica
75 Barytes
25 Silica
Wedgw.
I55
150°
Effects.
Formed a white brittle mafs
A brittle hard mafs, femi
tranfparent at the edges.
ryo0
148°
148°
lyo"'
66 Barytes
33 Silica
150"
Melted into a hard, fomewhat
porous, porcelain mafs.
A hard mafs not melted.
The edges melted into a pale
greenifh mafs, between a porce¬
lain and an enamel.
Melted into a fomewhat po¬
rous porcelain mafs.
Melted into a yellowifh, and
partly greenifh white, porous
porcelain.
,1451
Glafs.
11. Silica alfo enters into combination with ftron-
tites. Three parts of ftrontites and one of filica, ftrong-
ly heated in a filver crucible for an hour, afforded a
gray, fonorous, vitreous mafs, which has no tafte, and
is infoluble in water.
12. Siliceous earth enters with difficulty into com¬
bination with magnefia j but if equal parts of filica and
magnefia be expofed to very ftrong heat, they melt in¬
to a white enamel.
13,
6o8
Silica, See.
CHEMISTRY.
• Ann. dt
dim. xxxi.
p. 448.
I4S3
Porcelain.
T4S4
Prepara¬
tion.
I4S5
Properties.
•}■ Foureroy,
Hi. 213.
I4S6
Prepara¬
tion
* Ibid. iii.
p. 310.
12. But the moft important compounds of all the
earths are thofe of filica and alumina. Thefe earths
may be combined together, as appears -from the expe¬
riments of Guyton, in the humid way. He mixed
together equal parts of alumina diffolved by means of
potalh, and of filica held in folution by the fame al¬
kali. When the folutions came into contaft, a brown
zone was immediately formed, which fpread by agita¬
tion through the whole mafs, and communicated to it
a yellowidi colour. The mixture was no farther
changed during the fpace of an hour, although it was
occaiionally ftirred with a glafs rod ; but at the end of
that time the whole mafs aflumed the appearance of a
thick, opaque, white jelly *. When the filica and
alumina are mixed together, and formed into a pafte
with water, and expofed to heat, they flrongly cohere,
and affume a confiderable degree of hardnefs. This
compound forms the bafes of all kinds of pottery and
porcelain.
I. Compounds of Silica with Acids.
1. Muriate of Silica.
When muriatic acid is poured upon a folution of fi-
licated potafh, part of the filica remains in the folu¬
tion combined wuth the acid. I o this compound
Fourcroy has given the name of muriate of filica. This
folution wdiich is perfeftly tranfparent, is always acid.
When it is concentrated by a flow evaporation, it af-
fumes the form of a tranfparent jelly. But if the fo¬
lution be boiled, it is decompofed, and the filica is
precipitated in the form of fmall cryftalline particles,
fo that it is totally feparated from the water and the
acid f.
2. Fluate of Silica.
Fluoric acid combines with filica, either in the
gafeous or liquid flate. When it is difengaged. from
lime in the ftate of gas, by means of an acid, if the
procefs be performed in glafs veffels, they are corroded.
The fluoric acid in the ftate of gas combines with the
filica, and retains it, even when it is condenfed by
water. This earth may be precipitated from tlm liquid
folution by means of an alkali. When fluoric acid
gas is condenfed by water, part of the filica with
which it was combined, is precipitated ; but this por¬
tion is at laft diffolved by newr additions of the acid,
fo that the fait is in the ftate of an acidulous fluate. If
this folution be evaporated, a quantity of filica, cor-
refponding to the portion of acid difengaged, is de-
pofited, and the liquid which remains, contains a por¬
tion in proportion to that of the acid which is left in
the folution J.
3. Fluate of Potaftr and Silica.
This triple fait is formed, when a folution of fluate
of potafh is expofed to heat in glafs veffels •, or, when
the fluoric acid which has been prepared in glafs vef¬
fels is combined with potafh. But the nature of this
triple fait has not been examined.
4. Fluate of Soda and Silica.
This triple fait is formed in the fame way as the
former.
5. Borate of Silica.
Boracic acid and filica combine together by means
of a ftrong heat, and form a tranfparent glafs. T o
this Fourcroy has given the name of borate of Jihca.
This compound has no tafte, is not altered by the air,
nor is it foluble in water.
6. Phofphate of Silica. .
This compound of phofphorie acid and filica is form¬
ed by means of fufion j and the. compound is a hard,
denfe, tranfparent glafs. W7hen it is expofed to ftrong
heat, it combines with the alkalies, and forms a triple
fait. It is not decompofed by any of the acids. .This
fubftance is employed in the fabrication of artificial
gems.
Sect. VII. Of Tttria and its Combinations.
Yttna.&c,
45?
I. This earth was difeovered by Gadolin in 1794 iHiftory
and the account of his analyfis of the mineral fiom
which it is obtained, was publiftied in the memoirs 01
the Swedifti academy, and in Crell’s Annals for the
year In 1797 Ekeberg analyzed the fame mine¬
ral, and confirmed the refults of Gadolin. To the
new earth found in this mineral, Ekeberg gave the
name ofyttria, derived from Ttterby, a place in Sweden
where the ftone is found. The fame mineral was
afterwards analyzed by Vauquelin and Klaproth, about
the year 1800. The mineral from which this earth is
obtained, has received the name of gadolinite, is of a
black colour, has a vitreous frafture, and its fpecific
gravity is 4.0497. It is magnetic. When it is heat¬
ed with borax, it melts, and communicates to the fait
a yellowhh colour inclining to violtt. I he component
parts of this mineral are,
Yttria .47
• Silica .25
Oxyde of iron .18
Alumina .04
•94
2. Yttria is obtained from this mineral, by icducingprepara_
it to powder, and adding a mixture of nitric and mu-tion.
riatic acids, till the whole is decompofed. 1 he folu¬
tion is then to be filtered, and evaporated to drynels.
If then it be diluted with water, the filica will remain
behind. The liquid which paffed through the filter is
alfo to be evaporated to drynefs, and what remains is
to be expofed to a red heat in a clofe veffel. It is
afterwards diffolved in water, and filtered. The li¬
quid which paffes through the filter is tranfparent and
colourlefs. By adding a folution of ammonia, a preci¬
pitate is formed, which being collefted,. is pure y ttria.
2. This earth is in the ftate of a white powder. Itpr0perti^.
has neither tafte nor fmell. It is not fufible. It is
not foluble in water, or in any of the cauftic fixed al¬
kalies, but it readily diffolves in carbonate of ammonia.
The fpecific gravity of this earth is 4.842.
4. This earth undergoes no change by the aaion of
light. It is not afted on by oxygen, azote, or hydro¬
gen, nor does it combine with fulphur. It forms com-
& pounds
k
C H E M I
Yttria, Stc. pounds with the acids. Thefe falls have a fweetifli,
auftere tafte, and feme of them have a red colour.
I. Compounds of Yttria with the Acids.
S T R Y.
X45o
Prepara¬
tion.
1461
Properties.
I. Sulphate of Yttria.
r. Sulphuric acid combines readily with yttria, and
during the combination there is an evolution of calo¬
ric 3 and as the union goes on, the fait which is form¬
ed, cryftallizes in fmall brilliant grains.
2. Thefe cryftals are fometimes irregular, but often
have the form of fix-fided prifms, terminated by four-
fided fummits, and are of an amethyft red colour.
This fait has a fweetifh aftringent tafte, fomething like
the fait of lead. The fpecific gravity is 2.791. It
undergoes no change by expofure to the air. It is fo-
luble in about 50 parts of cold w'ater, but lefs fo where
there is not an excefs of acid. This fait is partially
decompofed when expofed to a red heat.
Unknown.
146*
Prepara¬
tion.
2. Sulphite of Yttria.
3. Nitrate of Yttria.
* Ann. de
Cbim.
XXX vi. 143.
Nitric acid combines with yttria by diflblving the
earth in the acid. This fait cryftallizes with difficulty.
When it is evaporated by heat, if too much be applied,
in place of becoming folid as other falls, it becomes foft,
and affumes the appearance of a thick, tranfparent
honey. When it cools, it becomes hard and brittle.
It deliquefees in the air. When fulphuric acid is
poured into a folution of nitrate of yttria, a precipi¬
tate is formed which cryftallizes. Thefe are cryftals
of fulphate of yttria *.
4. Muriate of Yttria.
This fait, which is the compound of muriatic acid
and yttria, refembles the nitrate in many of its proper¬
ties. It dries with difficulty, is fufible with a moder¬
ate heat, and is deliquefeent in the air. This fait is
decompofed by ammonia.
c. Fluate of Yttria. 1 1
6. Borate of Yttria. J unkn0WI1*
7. Phofphate of Yttria.
Phofphoric acid does not precipitate yttria from its
combination wdth the other acids; but the phofphate of
foda decompofes the falls of yttria, and forms a phof¬
phate of yttria, which is precipitated in white, gelatin-
j Ibid. 158. ous flakes f.
1463
Prepara¬
tion.
Unknown.
1464
Prepara-
ion.
8. Phofphite of Yttria.
9. Carbonate of Yttria.
609
This compound of carbonic acid and yttria was form¬
ed by Klaproth, by precipitating the earth by means
of an alkaline carbonate, from its folution in acids.
The carbonate of yttria is in the form of an infipid
white powder. It is infoluble in water.
The component parts of this fait are,
Vol. V. Part II.
Acid 18
Yttria 55
Water 27
Glucina,
&c.
too
10. Arfeniate of Yttria.
This fait is formed by boiling the earth in the acid.
A white powder is precipitated, which is arfeniate of
yttria.
11. Tungftate of Yttria. "j
12. Molybdate of Yttria. I .
13. Chromate of Yttria. runknown-
Columbate of Yttria. J
15. Acetate of Yttria.
This fait is formed by the direft combination of the
the earth with the acid. By evaporating the folution,
a fait is obtained in cryftals. Thefe cryftals, which
are of a red colour, are in the form of fix-fided plates
obliquely truncated. This fait undergoes no change
by expofure to the air.
16. Oxalate of Yttria.
This fait is formed by adding oxalic acid to the fo¬
lution of yttria in acids. A precipitate is formed i».
the ftate of a white powder, which is infoluble in wa¬
ter. It may be obtained alfo by employing the oxa¬
late of ammonia.
17. Tartrate of Yttria.
This compound is formed by precipitating yttria
from its folution in acids by means of tartrate of pot-
affi. This fait is foluble in water.
18. Citrate of Yttria.
19. Malate of Yttria.
20. Gallate of Yttria.
21. Benzoate of Yttria..
unknown.
22. Succinate of Yttria.
If the fuccinate of foda be added to a concentrated
folution of muriate or acetate of yttria, a precipitate is
formed, which is the fuccinate of yttria in the ftate .of
cubic cryftals.
23-
24.
2J-
26.
27.
Saccolate of Yttria.
Camphorate of Yttria
Suberate of Yttria.
Mellate of Yttria, j
Ladlate of Yttria. J
unknown.
28. Pruffiate of Yttria.
The pruffiate of potaffi cryftallized and re-diflblved
in water, caules a precipit >.te in the folution of yttria
in acids. This is in the form of a white, gritty mat¬
ter *.
Sect. VIII. Of Glucina and its Combinations.
* Ann. de
Cbim. xxxvL
p. 158.
1465
I. This earth was difeovered by Vauquelin in theHiftory.
year 1798. He was requefted by Haiiy to analyze the
the beryl, to afeertain whether its conftituent parts
4 H were
6io
Glucina,
&c.
1466
Prepara¬
tion.
'* Fourcroy,
ii. p. 157.
1467
Properties.
■}■ Annul, de
Chim. xliii.
S77.
1468
Hydroful-
phuret.
1469
Adlion of
■water.
1470
Of acids,
C H E M I
were tlie fame with thofe of the emerald, which the
latter had conjeaured, in obferving a perfea corre-
fpondence in ftruaure, hardnefs, and fpecific gravity.
In the courfe of this analyfis, Vauquelin difeovered the
new earth, to which, from its properties, he gave the
name of glucina, from the Greek wmrd yAuxaj, which
lignifies fweet. • The fame experiments were lepeated
by Klaproth and Bindheim, and the refults which were
obtained by Vauquelin confirmed.
2. This earth is obtained by the following procefs.
One hundred parts of the beryl or emerald, reduced to
a fine powder, are fufed with 3®® parts of caufiic pot-
alh. The fufed mafs is then diluted with difiilkd wa¬
ter, and diiTolved in muriatic acid. The folution is
to be evaporated to drynefs, taking care to llir it to¬
wards the end of the evaporation. Dilute the refiduum
with a large quantity of w'ater, aftd filter it. The fi-
lica is thus feparated by means of the firft procefs.
The filtered folution, which contains the muriates of
alumina and glucina, is. precipitated by carbonate of
potafii. The precipitate is to be well walked, and
diffolved in fulphuric acid. Add to this folution, a
quantity offulphate of potalh, and evaporate to obtain
cryftallized alum. When by a new addition of ful-
phate of potalh, and by a new evaporation, the folu¬
tion yields no more alum, add to it a iolution of car¬
bonate of ammonia in excefs, and agitate it well. I lie
glucina, after being depofited, is diffolved by means of
the excefs of this lalt, and the fmall quantity of alu¬
mina which may remain, is precipitated without being
diffolved. After fome hours, when the aluminous
precipitate is not diminiflied in volume by a new addi¬
tion of carbonate of ammonia and agitation, the folu¬
tion is to be filtered, and boiled in a glafs matrafs, and
as the carbonate evaporates, there is precipitated a
white, gritty powder, which is carbonate of glucina.
The carbonic acid may be driven off, by expofing the
powder in a crucible to a red heat *.
3. Glucina prepared by this procefs, is in the form
of a foft powder, or light white fragments, infipid to
the tafte, and which, adhere to the tongue.. The fpe¬
cific gravity is 2.9^7 ']'• B is altogether infufible in
the fire, and it neither contra&s nor becomes harder,
like alumina. It has no effefl on vegetable colours.
4. There is no a£iion between glucina and oxygen,
azotic, or hydrogen gafes. It is not changed by ex-
pofure to the air, nor is it afted on by carbone, phof-
phorus, or fulphur. It combines with fulphurated
hydrogen. When fulphurated hydrogen gas is made
to pafs into water in wdiich. this earth is fufpended, it
combines with it, and forms a hydrofulphuret, whofe
properties are fimilar to thofe of the other hydroful-
phurets. . . _
5.. Glucina is infoluble in water ; but it forms with
this liquid in fmall quantity, a pafte which is {lightly
du&ile, but has lefs tenacity than that of alumina.
6. Glucina combines readily with all the acids, and
forms with moft of them foluble falts, which are di-
ffinguilhed by a fweet and {lightly aftringent tafte.
Its affinities are in the following order.
Sulphuric acid,
Nitric,
Muriatic,
Phofphoric,
Glucina,
See.
t 
1471
Of alkalies.
147*
Gharac-
teriftic pro¬
perties.
* Fourcroy,
ii. 161.
S T R Y.
Fluoric,
Boracic,
Carbonic.
7. This earth is foluble in folutions of the fixed al¬
kalies. It is alfo foluble in carbonate of ammonia, but
it is infoluble in pure ammonia.
8. The cbaracleriftic properties of this earth are, ac¬
cording to Vauquelin, the following.
a. It forms with acids fweetilh and {lightly aftnn-
gen.t falts.
b. It is foluble in fulphuric acid when a little in
excefs.
c. It.decompofes aluminous falts, by feparating the
earth when it is boiled in their folutions.
d. The falts of glucina are completely precipitated
by ammonia.
e. It is foluble in the liquid carbonate of ammonia.
/. The affinity of this earth for the acids is between
that of magnefia and alumina *.
I. Compounds of Glucina with Acids.
1. Sulphate of Glucina. 1473
1. This fait, which was firft difeovered by Vauque-^TPara"
lin, is prepared by the direft combination of ful¬
phuric acid with the earth, either in the pure ftate, or
in that of carbonate. The folution is to be evaporated
to the confiftence of fyrup, and cryftals are obtained
on cooling. _ 1474
2. This fait cryftallizes with difficulty in the form Properties,
of fmall needles $ but their form has not been accurate¬
ly afeertained. It has a fweet, and fomewhat aftrin¬
gent tafte. It is not perceptibly altered by expofure to
the air, and is very foluble in water. 1475
3. When it is expofed to heat, it melts, fwells up, AAknof
and then dries. With a red heat it is entirely decom-lieat-
pofed, the acid is driven off in the ftate of vapour, and
the pure earth remains behind. 1476
4. This fait is not decompofed by any of the acids, Cm acids,
but it is decompofed by the alkaline and moft of the &'c'
earthy bafes. The infufion of nut-galls added to a
folution of this fait produces a yellowilh white precipi¬
tate, which is charafteriftic of the fait f. t Fourcrty
Connaifs.
2. Sulphite of Glucina. CLim.iii.
This fait is yet unknown. 49’
3. Nitrate of Glucina.
1477
T. The compound of nitric acid and glucina is form-Prepara-
ed by the diredl combination of the acid and earth in atloru
ftate of purity. The folution is evaporated by a mo¬
derate heat to drynefs, and then the fait is obtained in
the ftate of powder. * _ _ I47g
2. The nitrate of glucina does not cfyftallize. It is pr0perties.
either in the form of pow7der, or in that of a foft duftile
mafs. The tafte is fweetifh and aftringent. 1479
3. It is extremely deliquefeent in the air, and is Adlion of
very foluble in water. It readily melts when expofed heat*
to heat, and if the heat be increafed it is decompofed j
the acid is driven off in the gafeous form, and the earth
remains behind. It is only decompofed by fulphu-
tic acid UM146.
4. Nitrite of Glucina.
Unknown.
5. Muriate
C H E M I S T R Y.
Cilucina,
&c.
5. Muriate of Glucina.
U—This fait, according to Vauquelin, by whom only it
has been defcribed, comes very near the nitrate of
glucina in its properties. It feems to cryftallize with
more facility, but the cryftals are fo fmall that the form
cannot be determined. It does not deliquefce in the
air. When it is diffolved in alcohol, and diluted with
wrater it affords a very agreeable fweet liquor.
It is decompofed by heat, by the fulphuric acid, the
nitric, and by the phofphoric with the afliitance of heat.
6. Fluate of Glucina, 7 1
7. Borate of Glucina, J l“lr'-ncmn!’
8. Phofphate of Glucina.
1480
Prepara- 1. Vauquelin procured this fait by adding the phof-
tion. phate of foda to the folution of the nitrate, the fulphate,
or muriate of glucina. A copious mucilaginous matter
is inllantly precipitated. Or it may be obtained by
heating together the muriate of glucina and phofpho-
1481 r*c ac^ ’n t^e of glafs.
Properties. 2. This fait does not cryflallize, but is in the form
of mucilage or of white powder. It has no perceptible
tafte. It is not altered by expofure to the air, and it
is infoluble in water without an excefs of acid. It is
not decompofed by flrong heat. It melts under the
blow-pipe into a tranfparent vitreous globule. It is
decompofed by the fulphuric, nitric and muriatic
acids.
9. Phofphite of Glucina.
Unknown.
10. Carbonate of Glucina.
1484 , . .
Prepara- i. The compound of carbonic acid and glucina,
ti°n. which was difcovered by Vauquelin, and only examin¬
ed by him, is prepared by expofmg the earth to the air,
from which it attracts the acid, or hy precipitating fome
of the foluble falts of glucina by means of an alkaline
carbonate. The precipitate is to be walked with wa-
1483 ter, and dried in the air.
Properties. 2. This carbonate is in the ftate of a white powder,
foft and greafy to the touch. It has not the fweet
tafte of the other falts of glucina. It is not changed
by expofure to the air, and is infoluble in water. When
expofed to heat, the acid is driven off, and the pure
earth remains behind. It is decompofed by all the
acids with a brilk effervefcence.
II. Carbonate of Ammonia and Glucina.
This triple fait is formed by adding the earth of
glucina to a folution of carbonate of ammonia. It is
foluble in the fame quantity of water which holds the
carbonate of ammonia in folution. Its other proper¬
ties are unknown.
1 2. Arfeniate of Glucina,
13. Tungftate of Glucina,
14. Molybdate of Glucina,
15. Chromate of Glucina,
16. Columbate of Glucina,
!> unknown.
17. Acetate of Glucina.
Glucina readily diffolves in acetic acid. This fait
does not cryftallize j but by evaporation it is reduced to
6fi
Zircon! ai
a gummy fubftance, which becomes llowly dry and
brittle. For a long time it retains a kind of du£lility. , &'c’
The tafte is fweet and ftrongly aftringent.
18. Oxalate of Glucina,
19. Tartrate of Glucina,
20. Citrate of Glucina,
21. Malate of Glucina,
22. Gallate of Glucina,
23. Benzoate of Glucina.
■ unknown.
24. Succinate of Glucina.
This fait, according to Ekeberg, is formed by pre¬
cipitating the earth from its folutions, by means of
the fuccinates. It is therefore, nearly infoluble.
25. Saccolate of Glucina,
26. Camphorate of Glucina,
27. Suberate of Glucina,
28. Mellate of Glucina,
29. Laftate of Glucina,
30. Prufliate of Glucina,
31. Sebate of Glucina,
jS> unknown.
Sect. IX. Of Zircon 1 a and its Combinations.
1484
1. The name of this earth is derived from a ftone Hiftory,
called "zircon or jargon, which is found in the ifland of
Ceylon. It was from this ftone that Klaproth extraft-
ed the earth, fome time before the year 1793. He
foon after found the fame earth in the oriental hyacinth.
By this difcovery, Guyton was led to analyze the
hyacinths of France j and in thofe which were collefled
in the river tof Expailly, he detected the fame earth.
The experiments of Klaproth and Guyton wTere repeat¬
ed by Vauquelin, and their refults were confirmed, fo
that the nature and properties of this earth have been
fully developed. 14gj'
2. Zirconiais extracted from this mineral, in which Prepara-
alone it has been found, by the following procefs. Atlon*
quantity of the mineral is to be reduced to fine powder,
and fufed with five or fix times its weight of pure pot-
afh, in a filver crucible. The fufed mafs is then dif¬
folved in water, by which means the alkali is feparated.
The refiduum is then diffolved in muriatic acid, which
is to be heated, to feparate the filica ; and when no
farther precipitate appears by means of heat, add a
cauftic fixed alkali. Another precipitate is formed
which is to be well waftied and dried. This is pure
zirconia. 1485
3. Zirconia thus prepared, is in the ftate of fine Properties,
white powder, which is nearly foft to the touch, and
without tafte or fmell. When it retains water, it af-
fumes the form of a jelly, and is femitranfparent. The
fpecific gravity is 4.3. _ ^ _ I4g7
4. Light has no adlion on this earth. When it is Asftion of
expoled to the heat of the blow-pipe, it remains infu-1liea£-
fible, but gives out a yellowifh, phofphoric light. Heat¬
ed in a charcoal crucible, and furrounded with powder¬
ed charcoal, it undergoes a kind offufion, but without
becoming tranfparent, or affuming a vitreous form. It
becomes extremely hard, ftrikes fire with fteel, and
fcratches glafs.
5. There is no aftion between zirconia and oxygen
or azotic gafes, nor is it changed by expofure to the
4 H 2 air.
6l2
Z.rconia,
&c.
1488
Of water.
* Ann. tie
Chim. xxii.
IP7*
1489
Of acids.
CHEMISTRY.
air. It is not afted on by hydrogen, carbone, phof-
phorus, or fulphur.
6. This earth is infoluble in water 5 but it mixes with
a confiderable portion of this fluid, and forms with it a
tranfparent jelly. If in this ftate it be llowly dried,
it retains the water, and affumes a yellowifh colour,
and fomething of the tranfparency of gum arable *.
When it is dried in a very high temperature, it lofes
more than one-third of its weight. After having been
expofed to a red-heat, it becomes of a gray colour, harlh
to the feel, and lefs foluble in acids.
y. Zirconia combines with the acids, and forms with
them peculiar falts. Many of thefe are infoluble in
water, and are diflinguifhed by an aftringent tafle.
The order of the affinities of this earth, is the fol¬
lowing :
and by an infufion of nut galls in alcohol, w-hich af- Zirconia,
fords a white precipitate, foluble in an excefs of this ^
infufion. But if the zirconia contain iron, the colour y"“~“
of the precipitate is bluifh gray, of which a part re¬
mains in the folution, communicating to the liquor a
pure blue colour. When this liquid is mixed with
carbonate of ammonia, it affords a purple matter, by
the refracted rays, but of a violet colour by refledled
light. Cryftallized gallic acid alfo precipitates the
nitrate of zirconia, of a bluifli gray colour. Molt of
the other vegetable acids alfo decompofe this fait, and
form combinations with the earth wliich are infoluble
in water
4. Nitrite of Zirconia.
Unknown.
1 Annul, de
Chim. xxii.
p.
. A4? Vegetable acids,
Affinities. o,i-
oulphunc,
, Muriatic,
Nitric.
Action 0'f 8* Zirconia does not combine with the alkalies by
alkalies. fuflon, and is infoluble in liquid alkalies. It may be
diffolved, however, by the alkaline carbonates.
I. Compounds of Zirconia with the Acids,
x. Sulphate of Zirconia.
1. This fait is formed by the direft combination of
The folution is to be
149^.
Preparation . ,
and proper- the earth with fulphuric acid
ties. evaporated to drynefs. The fait thus obtained is in
the form of a white powder, which is very friable.
Sometimes it is in the form of cry Hals like fmall needles.
It h as no tafte, is not changed by expofure to the air,
and is infoluble in water.
2. This fait is readily decompofed by heat, the acid
is driven off, and the earth remains behind. When it
is boiled in water, the earth is precipitated, and the
acid remains in the liquid. At a high temperature it
is dccompofed by charcoal, and converted into a lul-
phuret which is foluble in wTater, and the folution fur-
nilhes by evaporation, cry Hals of hydrofulphuret of
•| Ibid. ipg. zirconia f.
*493
Action of
heat.
2. Sulphite of Zirconia.
Unknown.
3. Nitrate of Zirconia.
T494
Prepara¬
tion.
1495
Properties.
1496
AdliOiJ o‘
water and
keat.
1497
Of acids,
&.C.
1. This fait is formed by the dire& combination of
zirconia with concentrated nitric acid j and by evapo¬
ration it is obtained in the form of a yellowifli, tranf¬
parent, vifeid mafs, which dries with difficulty.
2. This fait has a flyptic and aftringent tafte, and
leaves on the tongue a thick matter, which proceeds
from a decompofltion of the fait by means of the fa-
liva.
3. When nitrate of zirconia, after being evaporated,
is put into diftilled water, a very fmall quantity only is
diflblved. The greateft part remains under the form
of gelatinous and tranfparent flakes. This fait is very
readily decompofed by heat.
4. It is alfo decompofed by fulphuric acid, which
forms in the folution a white precipitate, foluble in ex¬
cefs of acid y by carbonate of ammonia, which pro¬
duces a precipitate, foluble in an excefs of this faltj
5. Muriate of Zirconia.
• • 1• n *498
1. Of all the acids, the muriatic combines moft prepara-
readily with zirconia, when the latter is in the ftatetion.
of carbonate. This fait was firft formed by Klaproth,
and its properties were afterwards more particularly in-
veftigated by Vauquelin.
2. Th^ muriate of zirconia has no colour, but poflef- properues.
fes a very aftringent tafte, is very foluble in w ater, and
alfo in alcohol. By flow evaporation, it affords fmall,
tranfparent, needle-formed cryftals, vvhofe figure has
not been determined. When muriate of zirconia con¬
tains any portion of filica, the cryftals are cubical,
have little conftftence, and referable a jelly. Thefe
cryftals expofed to the air, gradually lofe their tranf¬
parency, and are diminiftied in volume. There are
formed, in the middle of the mafs, white lilky cryftals
in the thape of needles, which arile from the cubes. 150*
3. Muriate of zirconia is decompofed by beat, which Afttun of
drives off the acid. It is even decompofed in the heat,
mouth by means of the faliva.
4. a. It is alfo decompofed by fulphuric acid, which o|. acicjs
forms a precipitate with the earth in heavy white &<;.
flakes, while another part is retained in folution by
the muriatic acid. But by the affiftance of heat, the
latter is diffipated, and the remaining part of the ful-
phate of zirconia is depofited. If the evaporation be
flopped before it is brought to a ftate of drynefs, it af¬
fumes the appearance of a jelly by cooling. The ful-
phate of zirconia is then foluble in muriatic acid.
b. This fait is alfo decompofed by the phofphoric,
citric, tartaric, oxalic, and faclaftic acids, which form¬
ing with its bafe infoluble compounds, precipitate in
the form of white flakes.
c. The gallic acid precipitates the muriate of zirco¬
nia in the form of a white matter, if the fait has been
pure, but of a grayifh green if it contain iron. In
the latter cafe, the precipitate becomes, when dry, of
a firming black colour, which has the fame appearance,
as china ink. The liquid, in which are formed the
gallates of zirconia and iron, preferves a green colour j
and although new portions of gallic acid are added,
no farther precipitation is produced. But the carbo¬
nate of ammonia throws down a copious fLky matter,
wffiich has a purple colour, and nearly refembles that
of lees of wine. Thus, it appears, that the gallic acid
has a greater affinity for zirconia than the muriatic,
and that the gallates of zirconia and iron are foluble in
muriatic acid.
d. The
Zirconia,
&c.
* Ann. de
Chim. xxii
*>■ p. 201.
i5°a
Compofi-
tion.
C H E M I
d. The carbonate of potafh, when fully faturated,
decompofes the muriate of zirconia ; and although this
folution is attended with effervefcence, the'precipitate
waflied and dried in the air, retains a large proportion
of carbonic acid •, for when this earth is afterwards
diffolved in acids, it produces a brifk effervefcence.
The carbonate of ammonia at firft forms a precipitate
in the folution of muriate of zirconia. This precipi¬
tate is in great part re-diffolved by new additions of
the ammoniacal fait, and there is produced a triple
fait, which may be decompofed by heat.
e. A folution of fulphurated hydrogen gas in water,
mixed with a folution of muriate of zirconia containing
iron, becomes turbid, and produces a reddifh colour;
but there is no real precipitate. Hydrofulphuret of
ammonia inflantly precipitates this earth of a fine
green colour, which appears black when it is dry.
When this precipitate is placed on burning coals, it
emits the odour of fulphurated hydrogen gas, and be¬
comes of a purple blue colour when reduced to pow¬
der.
f. Pure alumina decompofes the muriate of zirconia,
with the aid of heat. The alumina is difiblved, the
liquid becomes milky, and affumes the form of a jelly
as it cools. It has been remarked, when the muriate
of zirconia contains iron, it remains in folution with
the alumina, and the zirconia which has been precipi¬
tated in this way, contains no perceptible portion of
this metal.
g. The pruffmte of mercury produces in the folution
of muriate of zirconia, a copious white precipitate,
which is f )luble in muriatic acid.
h. A plate of zinc introduced into a folution of muri¬
ate of zirconia, produces a flight effervefcence. The
liquid becomes milky, and affumes the appearance of a
white femitranfparent jelly in a few days*.
6. Fluate of Zirconia,
7. Borate of Zii
8. Phofphate
9. Phofphite
10. Carbonate of Zirconia.
When an alkaline carbonate in folution is added to
a folution of muriate of zirconia, the earth is precipi¬
tated without effervefcence j and when this preci¬
pitate is expofed to heat in clofe veffels, it gives out
carbonic acid gas. It alfo enters into combination with
the alkaline carbonates, and forms with them triple
falts. This, Vauquelin obierves, is one of the remark¬
able charaflers of this fait.
The component parts of carbonate of zirconia, ac¬
cording to the fame chemift, are,
Zirconia, T
Zirconia, (
: of Zirconia, f"
of Zirconia, J
unknown.
Acid and water,
Zirconia,
44-5
55-5
100.0
j> unknown.
j
S T R Y. 613
with it a fait which does not cryftallize. When the Zirconia,
folution is evaporated to drynefs, the acetate of zirco-, ^c‘
nia remains in the ftate of powder. This fait has an af-
tringent tafte, is not altered by expofure to the air, and is Properties,
very foluble in water and in alcohol. This fait feems
to have lefs tendency to be decompofed by heat than
the nitrate of zirconia *.
17. Oxalate of Zirconia,
18. Tartrate of Zirconia,
19. Citrate of Zirconia,
20. Malate of Zirconia,
21. Gallate of Zirconia.
}
^ Ann. da -
Chim xxii.
p. 206.
unknown.
Gallic acid added to a folution of muriate of zirconia,
it has been already mentioned, produces a precipitate
of a white matter, which is the gallate of zirconia. The,
properties of this compound have not been examined.
2 2. Benzoate of Zirconia,
23. Succinate of Zirconia,
24. Saccolate of Zirconia,
25. Camphorate of Ziiconia,
26. Subevate of Zirconia, >• unknown.
27. Mellate of Zirconia,
28. Laftate of Zirconia,
29. Piufliate of Zirconia,
30. Sebate of Zirconia. ■
Chap. XIV. Of METALS.
11. Arfeniate of Zbconia,
12. Tungftate of Zirconia,
13. Molybdate of Zirconia,
14. Chromate of Zwconia
J4. Columbate of Zirconia,
16. Acetate of Zirconia.
Acetic acid combines with zirconia, and forms.
1504
1. The metals, on account of their importance and importance
utility, have always greatly occupied the attention ofot metals,
mankind. Indeed fuch is their importance, that man
could not take afingle ftep in the improvement of even
the fimpleft of the arts of life, without the afliftance of
fome of the metals. In this view, the origin and im¬
provement of many arts, and the knowledge of metal¬
lic fubftances, may be, in fome meafure, confidered as
coeval. The metals, therefore, became very early*
and were probably the firft objefts of chemical invefti-
gation. In the extraordinary purfuits of the alchemilts,
they were the fubje&s of their eager refearches, in the
difcovery of the means of converting the more abund¬
ant and bafer metals, as they were called, into thofe
which were more valued, on account of their durabi¬
lity and fcarcity. They failed of their purpofe } but
their labours were not in vain. The fa£ts which they
difcovered in the progrefs of their inveffigations, were
of no fmall importance to fcience. I50^
2. The metals are diftinguifhed from other fub-C^ara<'iers"
fiances by a number of charadteriffic properties. Thefe-
are, brilliancy, colour, opacity, denfity, hardnefs,
elafticity, dudlility, malleability, tenacity, fufibility,
power of conducting caloric and ele&ricity. !jo6
3. Luff re or brilliancy is one of the moft flrikingBrilhancy,
charafteriftic properties of metallic fubftances, and
hence it has been denominated metallic lujlre. This is
owing to the refledlion of a great proportion of the
rays of light by metallic furfaces. On account of this
property, metals are employed in the conftruftion of
mirrors. Other fubftances, indeed, exhibit the ap¬
pearance of this brilliancy, which is the cafe with
the mineral called mica ; but in this fubftance, as well-
as every other which is not metallic, it is merely
fuptrficial, and it entirely difappears when the lurfacec
is
614
Metals.
C H E M
is broken, or fcratched with a iharp-pointed inftru-
ment. But the metal, treated in the fame way, be¬
comes more brilliant. The following is the order in
which the metals poiTefs this luftre :
Platina,
Steel,
Silver,
Mercury,
Gold,
Copper,
Tin,
Zinc,
Antimony,
Bifmuth,
Lead,
Arfenic,
Cobalt j and the other brittle metals.
tS°7
■dolour.
1508
Opacity.
1509
Denlity.
1510
Hardnefs.
4. Colour is one of the conflant properties of me¬
tallic fubftances, while it is only accidental and vari¬
able in other minerals. And as the metals are the
moft opaque, and the denfeft bodies in nature, colour
in them is very intenfe, or rather confounded with
their brillancy. The prevailing colour of metals is white;
fome however are yellow, and others reddifh. Thofe
of a white colour were formerly diftinguilhed by the
name of lunar metals, becaufe filver, which was called
luna, being placed at the head of thefe metals, has a
white colour. Gold, which was diflinguilhed by the
name offol, having a yellow colour, gave the name
of folar metals to fuch as refembled it. The colour of
metals is permanent, while they remain unaltered, but
it is often totally loll when they enter into new com¬
binations.
5. Jt is generally admitted, that all metallic fub¬
ftances are perfe£lly opaque. Newton indeed obferv-
ed, that gold-leaf when reduced to ^ 8b 0 of an inch
thick, appeared of a green colour, from which he con¬
cluded that it tranfmits the green rays ; and he fup-
pofed that other metals might alfo tranfmit light, if
they were fufficiently thin. But no metal has yet
been found fo malleable as to be reduced to that ftate
of thinnefs to permit light to pafs through it. Silver-
leaf fo thin as to be only -rffoWs- Part ar» inch, is
quite opaque.
6. The metals are particularly diftinguifhed from
other fubftances by their denfity. Metallic fubftances
have a greater fpecific gravity than any other bodies
in nature ; that is, the quantity of matter contained
in a given bulk, is greater in the metals than in other
fubftances. Even the lighteft of the metals poflefles a
greater denfity than the heavieft bodies known of any
other kind of matter. The particles of which they
are compofed muft therefore be in clofer contaft than
in any other body. To this greater denfity is owing
their fuperior luftre.
7. The metals differ from each other greatly in de¬
grees of hardnefs. In general, metallic fubftances are
not fo hard as many other natural bodies. The de¬
gree of hardnefs does not depend on the denfity, for
the hardeft metals are by no means the heavieft. This
property, therefore, muft: be owing to the nature of
the particles of which the metal is compofed, or to
fome peculiar difpofition or arrangement of thefe par¬
ticles. It is found that fome of the metals can be
I
I S T R Y.
hardened by art, merely by hammering, or by hidden Metals,
cooling after being heated. The hardnefs of metals ' '
too, is greatly increafed by being combined with each
other, or with other fubftances 5 as, for inftance, when
copper and tin are combined together, or iron and car-
bone in the formation of fteel, the utility of which lat¬
ter, as it is applied for cutting inftruments, depends on
its hardnefs. Metallic fubftances, in comparing their
different degrees of hardnefs, have been divided into
eight claffes, which are arranged in the following order.
1 ft, Iron and manganefe.
2d, Platina and nickel.
3d, Copper and bifmuth.
4th, Silver.
5th, Gold, zinc, and tungften.
6th, Tin and cobalt.
7th, Lead and antimony.
8th, Arfenic.
Mercury being always fluid at the ordinary tempera¬
ture of the atmofphere, cannot be compared with re¬
gard to this property; and the degree of hardnefs
which fome of the other metals poffefs has not been
afeertained.
8. The elafticity of metals feems to follow the fameEia[p”y.
order in which they poffefs the property of hardnefs.
The elafticity of fome metals can be increafed in the
fame way as their hardnefs, either by mechanical
means, as by hammering, or by new combinations. ^
9. One of the moft important phyfical properties of Dudlility.
the metals, is ductility. By this is meant that peculiar
property which fome metals poffefs, of being drawn out
into wire, without deftroying or diminifhing the cohe-
five power of their particles. Some metals poffefs this
property in a great degree, while others are entirely
deprived of it ; and fome metals are extremely dudtile,
while they poffefs in a very fmall degree another pro¬
perty, namely malleability. Iron is one of the moft
du&ile metals, but is much lefs malleable than many
others.
10. Malleability is alfo one of the moft valuable Malkabi-
properties of metallic fubftances. By this property lity.
they can be reduced to any form or ftiape which may
be wanted, for thofe purpofes to v>hich they are to be
applied. This property of malleability is fuppofed to
depend on the form of the particles, or on the mode
of their aggregation. Thofe metals wTich poffefs this
property of malleability or laminability, feem to be
compofed of fmall plates, while the du&ile metals
feem to have their particles arranged in a fibrous form.
When metallic fubftances are hammered, they be¬
come harder, denfer-, and more elaftic, wdrich is
owing to their particles being brought into clofer con-
11. Tenacity is expreftive of the power of cohefion Tenacity,
between the particle? of metallic fubftances. Different
metals poffefs this property in very different degrees.
The method which has been adopted to eftimate the
different degrees of tenacity, is by fufpending wiies of
the fame diameter of the different metals by one ex¬
tremity, and attaching weights to the other, till the
wires are broken. Iron, which has the greateft tena¬
city of all the metals, wffen foimed into wire, of an
inch in diameter, will fupport a weight of jcolb. with¬
out breaking, while a wire of lead of the fame diame¬
ter,
Metal'1.
1515
Fullbility.
1516
Conductors
of caloric
and elec¬
tricity.
1517
Oxidation
in the air.
1518
By heat.
C H E M
ter, can only fupport about 29 lbs. The following is
the order of the du&ile metals, according to the degree
of their tenacity.
Iron,
Copper,
Platina,
Silver,
Gold,
Tin,
Lead.
12. Another property of the metals is fufibility.
When they are expoled to a fufficient degree of heat,
they melt, and are reduced to the ftate of liquidity.
One of the metals, namely mercury, is always in the
fluid ftate, at the ordinary temperature of the atmo-
fphere. The different metals which are generally in
the folid ftate, require very different temperatures for
their fufion. Thus lead and tin require comparatively
a lower temperature to be melted ; while gold and pla-
tina can only be brought to the ftate of fufion, by the
greateft degree of heat that can be applied.
13. Metallic fubftances are the heft conduftors of
caloric, hut the comparative degrees of this property
have not been afcertained. They are alfb found to be
the heft conductors of electricity.
14. The metals poffefs fome properties in com¬
mon with other fubftances, as tafte and fmell, by
which fome of them are peculiarly diftinguiftied ; and
in being fufceptible of cryftallization, which is the
cafe with fome, or of being volatilized, as happens to
others.
15. But metallic fubftances are not only of vaft
importance in the arts of civilized life, on account of
the properties which we have now detailed, which be¬
long to them in the metallic ftate ; but many of them
are not lefs valuable in thofe changes which they un¬
dergo by new combinations, and the new properties
they acquire, in confequence of thefe changes. One
of the flrft and moft ordinary changes to which metal¬
lic fubftances are fubjecff, is their combination with
oxygen. This is called in chemical language
When a metal, as, for inftance, a piece of iron, is ex-
pofed to the air, when it is moift, it foon undergoes a
remarkable change. It lofes its metallic luftre, and
the furface it covered with a brownifti powder, well
known by the name of rujl. This change is owing to
the combination of oxygen with the metal, and the
ruft of the metal in this date is known in chemiftry by
the name of oxide. The procefs by which this com¬
pound of oxygen and a metallic fubftance is formed, is
called oxidation^ and the product is denominated an
oxide.
16. But this procefs of oxidation is effefted more ra¬
pidly when metals are expofed to the aSion of heat;
and indeed many metals require a very high tempera¬
ture to produce the combination, while it cannot be
accompliftred in others by the greateft degree of heat
that can be produced. This procefs was formerly called
calcination, or calcining the metal 5 and the product,
now denominated an oxide, was diftinguifhed by the
name of calx or calces, from its being reduced to the
ftate of powder, in the fame way as limeftone, by burn-
ing.
I S T R Y.
17. Metals differ very much from each other in the Metals,
circumftances in which this oxidation takes place, as in v 1
the temperature which is neceffary, the facility of the ^reoxidat-
combination, the proportions of oxygen which com-eci in dif-
bine, and the force of affinity between the conftituentferent cir-
parts of the oxide. Some metals are oxidated in the cum^anCes'
loweft temperature, as, for inftance, iron and man-
ganefe j while others require the greateft. degree of
heat that can be applied. Such are filver, gold, and
platina. 1520
18. The facility with which oxidation takes place in ^ air.
in fome metals is fo great, fuch as iron, tin, lead, cop¬
per, and manganefe, that they muft be completely de¬
fended from the aftion of oxygen ; but in gold and pla¬
tina, no perceptible change is obferved, for what¬
ever length of time they are expofed to the atmo-
fphere. _ _ 1522
19. This oxidation and the quantity of oxygen ah-Proportion
forbed is proportional to the temperature. There are, ot oxygen
hotvever, many metals which combine with a determi-
nate proportion of oxygen at certain temperatures, and
from this may be eftimated the quantity of oxidation
from the degree of heat which has been applied. The
rapidity of the oxidation is almoft always increafed by
the elevation of temperature. In this way actual com-
buftion or inflammation is produced, d hus filings of
metals thrown upon a body in the ftate of ignition,
give out brilliant fparks *, and fteel, (truck upon a flint,
burns with a vivid flame in the air, in confequence of
the great heat which is communicated to it by percuf-
fion.
2D. Metallic fubftances combine with very different
proportions of oxygen ; and this quantity varies ac¬
cording to the manner in which the procefs has been
conduced, or the temperature to which the metal has
been expofed. _ _ 1522
21. In thefe different dates and conditions of oxida-Different
tion, different phenomena are exhibited. Sometimes Phenomena
the metal becomes red hot, and is inflamed ; fometimes ^Xlda’
the oxidation takes place without fufion, or does not
combine with oxygen till after it has been melted ;
fometimes it is covered with a brittle cruft, or with a
fubftance in the form of powder. At other times a pel¬
licle, exhibiting different colours, forms on the fur-
face ; but, in all cafes, the metal is tarniftred, lofes its
brilliancy and its colour, and affumes another, which
announces the change that has taken place.
22. Another difference which takes place among Different
metals, is the different degrees of force with whiclr the affinities,
oxygen adheres to the metal. The knowledge of this,
and the different degrees of affinity between oxygen
and metallic fubftances, is of great importance in many
operations and chemical refults. 1524
23. During the fixation of oxygen in metallic fuh-Caloric
fiances, it is abforbed by fome in its folid ftate, and 0u^
gives out a great deal of caloric. In others it is com-^f1^0*1'
bined, without giving out the fame quantity. This
proportion of caloric given out correl'ponds to the faci¬
lity with which oxides part with their oxygen, or are
reduced to the metallic ftate. Thofe which have com¬
bined with oxygen with the greater proportion of calo¬
ric, are moft eafily reduced; hut thofe, on the contrary,
in which the oxygen has been deprived of its caloric,
are reduced to the metallic ftate by a great addition of
caloric,
\
616
CHEMISTRY.
Metals.
1525
Different
oxides.
1546
Theory of
Stahl.
1527
Overturn¬
ed.
ca’orrc, and the greateil number of oxides require the
addition of fubftances whofe affinity for oxygen is greater
than that of the metal.
24. Metallic oxides are extremely different in dif¬
ferent metals, and even in the fame metal, according to
the proportion of oxygen. They are, however, pof-
leffed of fome common properties. They are all in the
■form of powder or earthy lubllance, or fo brittle as to
be eaflly reduced to this Hate. They exhibit every
fliade of colour from pure white to brown and deep
red, and they are heavier than the metals from which
they have been obtained. Some oxides are revived,
as it is called, or are reduced to the metallic ftate,
merely by being in contadl with light or caloric. Some
require the addition of a corabuftible iubflance and a
high temperature} while others have fo ftrong an affini¬
ty for oxygen, that they cannot be deprived of it by
the ftrongeft heat, but become fulible in the fire, and af¬
ford a glaffy matter more or lefs coloured, and even ferve
as a flux to the earths. Some oxides are volatile, but the
greateil number are fixed. Some have an acrid and
cauftic talle, are more or lefs foluble in water, and
even poffefs an acid quality } others are infoluble and
infipid.
25. Obferving this remarkable change produced on
metallic fubftances by the adlion of air or of heat, phi-
lofophers began early to account for it. According
to Beecher and Stahl, the founders of chemical fcience,
metals are compofed of earth and phlogifton, and the
procefs which takes place during the calcination of a
metal, is merely depriving it of its phlogifton. This
doftrine wffiich had undergone various modifications,
from the difficulties which it prefented in accounting
for the phenomena of the calcination of metals, was
finally overthrown by the celebrated experiments of
Lavoifier. In one of thefe experiments he introduced
eight ounces of tin into a glafs retort, and having her¬
metically fealed it, after previous heating to expel
fome of the air, it was accurately weighed, and ex-
pofed to heat. The tin melted ; and a pellicle ap¬
peared on its furface, which was foon converted into a
gray powder. The heat was continued for three hours,
but no farther change appeared upon the metal.
When the retort was cooled, it was found to have the
fame weight as before the operation. The point of
the retort was then broken off, and a quantity of air
rufhed in. This was equal to xogrs. which was the
additional weight acquired by the retort. The whole
of the metallic fubftance in the retort was 10 grains
heavier than when it was introduced, fo that he con¬
cluded, that the 10 grains of air which had difappear-
ed, had combined with the metal, and caufed its in-
creafe of weight. The inference which-he drew from
this was, that the calcination of metals is not owing
to their being deprived of any fubftance, but to their
combination with air, and with the oxygen of the air;
lor it w'as found by future experiments, that the calcina¬
tion or oxidation of metals could not be effedled with¬
out oxygen ; and when it took place in a given quan¬
tity of common air, it was only the oxygen which was
abforbed. #
26. But as a ftill farther oroof, that the calcination
erf metals is owing to the abforption of oxygen, they
gre reduced by thofe fubftances which have a greater
2
affinity for oxygen. If charcoal in powder be mixed Metals,
with a metallic calx or oxide, the oxygen combines 1 "■ V’—"
with the carbone of the charcoal, forming carbonic
acid, and the oxide is reftored to the metallic ftate. If
this procefs be performed in clofe veffels, the quantity
of oxygen in the carbonic acid, correfponds to the
quantity which was abforbed by the metal during cal¬
cination.
27. From thefe obfervations, therefore, it appears,
that metallic fubftances combine with oxygen ; and it
has been obferved, that not only different metals com¬
bine with it in different proportions, but the fame me¬
tal forms compounds of one, two, and fometimes three I52*
different portions. No combination takes place be-
tween azote or hydrogen and metallic fubftances ^.ar-
but fome of them enter into combination with carbone, bone, See.
phofphorus, and fulphur, forming carburets, phofphu-
rets, and fulphurets. The metals alfo combine with
the acids, and form falts, fome of which are of the ut-
moft importance, not only in chemiftry, but alfo in the
arts of life. They alfo enter into combination with
each other, forming a clafs of bodies which are dif-
tinguiffied by the name of alloys.
28. Metallic fubftances were formerly divided into Diviiioi).
noble or per fell, and hnpcrfeR metals. The noble or
perfedl metals wrere platina, gold, filver, mercury ;
and the property on which this character w-as founded,
wras that of their being fufceptible of being reduced by
being expofed to heat. The other metals then known,
were called unperfeEl metals, becaufe to reduce them
to the metallic ftate, the addition of fome combuftible
fubftance wTas found to be neceffary. They wTere al¬
fo divided into metals and femimetals. Among the
firft wrere included thofe metals which were malleable
and duflile ; the femimetals comprehended thofe which
poffeffed neither of thefe properties, and were there¬
fore confidered as lefs perfefl. Thefe diftimftions,
however, are now neglected, becaufe they afford no
well-founded or juft marks of diferimination.
29. In the arrangement of the metals which we
propofe to follow', that of Fourcroy is adopted. He
has divided them into five different claffes, according
to their duftility, and the proportions of oxygen with
which they combine, or the facility with which that
combination takes place. In the firft clafs he includes
thofe metals which are brittle, and in fome of their com¬
binations with oxygen have acid properties. Thefe are,
Arfenic,
Tungften,
Molybdena,
Chromium,
Columbium.
The fecond clafs comprehends thofe which are brittle
and fimply fufceptible of oxidation. Thefe are the
following.
Titanium,
Uranium,
Cobalt,
Nickel,
Manganefe,
Bifmuth,
Antimony,
Tellurium.
The
a
C H E M
Arfenic, The third clafs comprehends thofe metals which have
, ^c‘ , fome degree of du&ility, which are only two. in num¬
ber, viz.
Mercury,
Zinc.
The fourth clafs, which confifts of three metals, includes
fuch as are du£tile, and eafily oxidated. Thefe are,
Lead,
Iron,
Copper.
The fifth clafs is compofed of three metals, which are
characterized by being very duCtile, but oxidated with
great difficulty. Thefe are,
Silver,
Gold,
Platina.
I53°
Natural hi- 30. To thefe preliminary obfervations we have only
to add, that metallic fubltances are found, either on
the furface or in the interior of the globe, and either
uncombined, or forming compounds with different fub-
ftances. Some metals, as gold and platina, are general¬
ly found in fmall grains, mixed with the foil. Thefe,
as well as the matters with which they are accom¬
panied, have proceeded from the decompofition of the
more folid parts of the globe. But metallic fubftan-
ces which are met with in greater abundance, exift in
the interior of the globe, in veins which traverfe the
other ftrata of the earth in different directions. The
^metals moft commonly found in veins are, lead, copper,
filver, zinc, mercury, and antimony. Some exift in
detached maffes.
31. Metals, as they exift in the earth, are either in a
ftate of purity, or the metallic ftate, when they are
called native or virgin metals ; or combined with each
other, when they are faid to be alloyed. They are
found alfo combined with other fubftances, very fre¬
quently with fulphur ; when they are faid to be mine¬
ralized : or, they are combined with oxygen, when
they come under the denomination of oxides ; or they
are combined with acids in the ftate of /alts.
Sect. I. Of jIrsenic and its Combinations.
1-3! I. It would appear that the ancients were acquaint-
Hiltory. ed with arfenic in its ftate of combination with fulphur,
which is a reddilh coloured mineral, and was employ¬
ed by them in painting ; and although Theophraftus
arranged it among metallic ftones, probably on account
of its weight, it was not known to pofi'efs a metallic
fubftance till the middle of the 17th century. Para-
celfus, indeed, who lived at an earlier period, is faid
to have known it in the metallic ftate •, but the procefs
of obtaining it from orpiment and arfenic, was only
firft defcribed by Schroeder in 1649. Lemery alfo
publilhed a procefs for extrafting this metal in 1675.
It was afterwards fully demonftrated by Brandt in
*733, and by Macquer in 1746, that arfenic poffeffed
peculiar properties, and is totally diftinft from all other
metals. Thefe fa£ls were farther confirmed by Mon-
net in 1773, and by Bergman in 1777.
1532 . 2> Arfenic is frequently found native, and is then
Found na- in dark-coloured maffes, which have little brilliancy,
Vot. V. Part II.
I S T R Y. 617
and exhibit no metallic luftre, except at the fra&ure. Arfenic,
It is frequently found combined with other metals. In ^
this ftate it is combined with iron, and is known by
the name of arfenicalpyrites, or mifpickel. One of the
moft frequent combinations of arfenic is with fulphur,
of which there are two principal varieties ; the one is
of a yellow^ colour, well known under the name of or¬
piment, and the other red, called realgar. It is alfo
fometimes found in the ftate of white oxide, or arfeni-
ous acid, but this is a rare occurrence.
3. In whatever ftate arfenic is found, it can eafily j-
be detected, by throwing a little of it on burning Method of
coals. The white fume which arifes, and the garlic anab'zm£
fin ell which is exhaled, are fufficiently charadfteriftic ofthe ores*
this metal. To obtain the metal from its oxide, it may
be mixed with three times its weight of black flux.
This mixture is put into a crucible, to which another
crucible inverted is adapted. They are then to be
luted together, to exclude the air. Apply heat to the
lower crucible till it becomes red, defending the upper
one as much as poffible from the beat, by means of a
plate of iron or copper, through which the lower cru¬
cible paffes. When the apparatus has cooled, a cruft
of metallic arfenic is found in the upper crucible, in
the form of cryflals. This being detached and weigh¬
ed, flrows the quantity of pure metal in the mineral
which has been tried.
In the humid way, Bergman recommends to treat
native arfenic by diffolving it in four'parts of nitro-
muriatic acid, concentrating the folution by evapora¬
tion, and precipitating the muriate of arfenic which is
formed, by means of water. If there is any filver, it
is firft precipitated in the form of an infoluble muriate,
and iron is fometimes found in the folution precipitated
by wTater.
The fulphurets of arfenic are to be treated by muri¬
atic acid, adding a fmall quantity of nitric acid, to fe-
parate the fulphur. The oxide of arfenic may then
be precipitated by water. The pure metal may be ob¬
tained by immerfing a plate of zinc in the folution,
having previoufiy added a quantity of alcohol.
4. Arfenic is in the form of fmall plates of a blackiftr Propertied
gray, brilliant, and metallic colour, with confiderable
luftre where there is a freffi fratlure. The fpecific
gravity is 8.31. It is extremely brittle, and is there¬
fore eafily reduced to powder. It has neither fmell
nor perceptible tafte when it is cold; but wdien it is
heated, and in the ftate of vapour, it is remarkable for
a ftrong fetid odour of garlic. It fublimes before it
melts, fo that its fufing point is not known. It is the
moft volatile of all the metals. When flowly fublimed,
it cryftallizes in the form of regular tetrahedrons, and
fometimes in that of oftahedrons. The tetrahedron is
the form of its integrant molecule.
5. When arfenic recently prepared is expofed to the Acftion of
air, it is foon tarnifhed, lofes its luftre, becomes at firft a‘r-
yellowiffi, and then paffes to a black colour. It lofes at
the fame time its hardnefs, and becomes extremely fri¬
able. When it is heated in contact with air, or if it
be thrown in the ftate of powder on burning coals,
it burns with a blue flame, and exhaling the ftrong
odour of garlic, is fublimed in the form of a white,
acrid, foluble mafs, which has been called the white
oxide of arfenic, or white arfenic. By this latter name
it is well known in the ftiops. To this oxide of arfe-
4 I nicj
6i8
Arfenic,
&c.
,iS36
Oxide or
arfenious
acid.
1537
Properties.
C H E M I
nic, becaufe it poffelTcs fome acid properties, Fourcroy
lias given the name of arfenious acid. This acid bears
the fame relation to arfenic acid as the phofphorous. and
fulphurous acids do to phofphoric and fulphuric acids.
6. This oxide or acid is extremely volatile. When
it is heated in clofe veffels, it is lubhmed m tranfparent,
regular tetrahedrons. It is extremely acrid and cauf-
tic, corroding and deftroying the organs of animals, io
that it is the moft violent poifon known. The fpecific
gravity is between 4 and 5. It reddens vegetable
blues, and when expofed to the air, it is covered with
a flight efflorefcence.
The arfenious acid is decompofed by hydrogen,
carbone, phofphorus, and fulphur.. At a red heat, the
hydrogen and carbone combine with the oxygen, and
reduce it to the metallic ftate. Phofphorus and ful¬
phur are partly converted into phofphoric and fulpnu-
ric acids, and partly combine with the arfenic, forming
2 phofphuret or fulphuret of arfenic.
8. This acid is very foluble in water. It. requires
about 15 parts of boiling water for its folution, from
which it may be obtained cryftallized on cooling, or
by flow evaporation. The cryftals are in the form of
regular tetrahedrons. The folution in water is ex¬
tremely acrid, reddens vegetable blues, combines with
earthy bafes, decompofes the alkaline fulphurets, and
affords with them a yellow precipitate in which the
srfenic returns to the metallic ftate. 1 he component
parts of arfenious acid are,
Arfenic 75>2'
Oxygen 24.8
100.0
1538 o. Arfenic combines with a greater proportion of
Arfenic oxygen •, and in this compound it ftill exhibits acid
;acid' properties, and is known by the name of ar/enic acid.
The method of preparing this acid and its properties
have already been defcribed, in the chapter on acids j
and the compounds it forms with the alkalies and
earths, have been particularly detailed in the chapters
which treat of thefe fubftances.
10. Arfenic does not decompofe water. It may be
kept for any length of time under water, without un¬
dergoing any change. There is no.aflion between ar¬
fenic and carbone or azote. Arfenic, however, is fo¬
luble in hydrogen gas, to which -it communicates a fe¬
tid odour and a poilonous property.
1539 11. Arfenic enters into combination with phofpho-
iPhofphuret. ms. When equal parts of phofphorus and arfenic are
diftilled together with a moderate heat, there is fu-
blimed a dark-coloured brilliant fubftance, which burns
on red-hot coals, with a mixed odour of arfenic
and phofphorus. This is the phofphuret of arfenic,
which muft be preferved under water. This compound
may be formed under water at a boiling temperature
in a matrafs. As the phofphorus melts, it combines
with the arfenic. The properties of this phofphuret of
arfenic have not been examined.
1540 12. Arfenic combines readily with fulphur, either
Sulphuret. furlon or by fublimation. The refult of this combi¬
nation is a yellow or red mafs. This compound of ful¬
phur and arfenic, which is a fulphuret of arfenic, is
found' native. The red is known by the name of real-
tar, and the yellow by that of orpiment.
S T R Y.
13. Arfenic enters into combination with the acids, Arfenic,
and forms with them peculiar falts. It alfo combines . ^ ,
with the metals, forming alloys. The following is the Ij;4I
order of the affinities of arfenic and of its oxide, as they Salts and
have been arranged by Bergman.
Arsenic. Oxide of Arsenic. Affinities.
Lime,
Muriatic acid,
Oxalic,
Sulphuric,
Nitric,
Tartaric,
Phofphoric,
Fluoric,
Saclaftic,
Succinic,
Citric,
Laftic,
Arfenic,
Acetic,
Prufiic.
14. Arfenic, in the metallic ftate, is fcarcely ap¬
plied to any ufe, except for chemical purpofes. It is
fometimes alloyed with the metals, by which means
they acquire new properties. In the ftate of white
oxide, it is much employed in the arts. It has even
been exhibited as an internal remedy in the difeafes of
cancer and intermittent fevers ; but in all cafes this
terrible poifon ought to be adminiftered with the great-
eft caution. To counteraft the effefts of arfenic when
it has been accidentally taken into the ftomach, one
of the belt antidotes is water impregnated with fulphu-
rated hydrogen gas, or fome of the alkaline fulphurets
diflblved in water *.
Nickel,
Cobalt,
Copper,
Iron,
Silver,
Tin,
Gold,
Platina,
Zinc,
Antimony,
Sulphur,
Phofphorus,
TS43
Ufcs.
* Fourcroy
v. p. 80.
t
I. Salts of Arfenic.
1. Sulphate of Arfenic.
Concentrated fulphuric acid hasnoa&ion on arfenic No
in the cold j but when they are boiled together, an
effervefcence takes place, fulphurous acid gas is difen-
gaged, the arfenic is oxidated, and falls to the bottom
in the ftate of white powder. According to Fourcroy,
this powder retains but a fmall portion of fulphuric
acid,* the whole of which is nearly carried off by waffi-
ing with water ; nor are cryftals obtained from the fo¬
lution. By evaporation the white oxide of arfenic is
precipitated, and fulphuric acid remains pure in the
folution. There is no a&ion between fulphurous acid
and arfenic.
2. Nitrate of Arfenic.
Concentrated nitric acid produces a violent a6hon Effe£4
with arfenic. Nitrous gas is difengaged, and towards
the end of the procefs, azotic gas. Fhe^ arfenic is
converted, at firft into the white oxide, which, with a
new addition of acid, paffes to the ftate of arfenic acidj
and when a rreat quantity of nitric acid is employed,
with the aid of heat, the metal is inftantly converted
into arfenic acid. There remains no oxide in the fo¬
lution, and there is no nitrate of arfenic formed.. But,
according to Bergman, when the nitric acid is diluted,
it diffolves the oxide, and affords a cryftallized fait
like the white oxide.
“5. Muriate
C H E M
Tungften, Muriate of Arfenic.
1S4<^
Prepara-
tioa.
* Fourcroy
v. p- 73-
I547
Oxy muria¬
tic acid.
1. Muriatic acid has no adlion on arfenic in the
cold : but when they are boiled together, the folution
takes place, and there is difengaged a fetid gas, which
feems to be arfeniated hydrogen gas. From this it
appears, that muriatic acid enables the arfenic to de-
compofe ivater. A little nitric acid added, promotes
the folution j and this folution, heated and concentrat¬
ed at firft in clofe veffels, is entirely fublimed in the
form of a thick liquid, which was formerly called butter
of arfenic. This fait is decompofed by water alone,
which precipitates the metal. The muriate of arfenic,
therefore, can fcarcely be conlidered as a permanent
fait *.
2. When arfenic in the ftate of powder is throwm
into oxymuriatic acid gas, it inftantly catches fire,
burns with a very brilliant white flame, and is con¬
verted into white oxide. If arfenic be added to liquid
oxymuriatic acid, it is converted into arfenic acid,
while the acid returns to the ftate of muriatic acid.
4. Fluate of Arfenic.
Fluoric acid combines with the white oxide of arfe¬
nic, and affords fmall grains, which have a cryftalline
form } but their properties are unknown.
5. Borate of Arfenic.
Boracic acid alfo combines with the white oxide of
arfenic, and affords a fait which is in the ftate of white
powder, or in the form of fmall needles. Their pro¬
perties are alfo unknown.
6. Acetate of Arfenic.
Acetic acid enters into combination with the white
oxide of arfenic, and forms cryftals, which are only
known to be difficultly foluble in water.
7. Oxalate of Arfenic.
Oxalic acid, combined with arfenic, affords cryftals
in the form of prifms. Similar cryftals are obtained by
the combination of arfenic with the tartaric acid.
8. Benzoate of Arfenic.
Benzoic acid combines with the white oxide of ar¬
fenic, and by evaporating the folution, plumofe cry¬
ftals are obtained. This fait has an acid and acrid tafte,
is foluble in water, fublimes with a moderate heat,
but with a ftronger heat is decompofed, and is not pre¬
cipitated from its folutions by alkalies.
Sect. II. Of Tukgsten and its Combinations.
IS4*
Hiftory-
I. The name of tungften is derived from a white,
tranfparent mineral, which contains this metal in the
ftate of acid united to lime. This mineral was ana¬
lyzed by Scheele in 1781, and he found that one of
its component parts is lime, and the other an earthy-
like fubftance, to which he gave the name of tungfic
acid. His difcovery was confirmed about the fame
time by Bergman, who conjeftured that the bafis of
the acid might be a metallic fubftance. This conjec¬
ture was verified by the experiments of Meflieurs
I S T R Y. 619
D’Elhuyart, two Spanilh chemifts, who difeovered'vlolybdenaj
the fame metal in the mineral call wolfram^ and afeer-
tained fame of its metallic properties. It has fince "v """
been farther examined by Vauquelin and Hecht, and
by Allen and Aiken of London.
2. This metallic fubftance has been only found in pQ^dna-
the ftate of acid in combination with lime, iron, man-tive.
ganefe and lead. When it is combined with lime, it
is the tungften of the Swedes, and in combination with
iron it is called wolfram. j^-o
3. To obtain this metal from the acid, it is mixedMethod of
with charcoal in a crucible, and expofed to a very obtaining
ftrong heat. By this procefs the metal was obtained iC‘
in the form of a fmall button at the bottom of the cru¬
cible in the firft experiments which were made upon
it by the German chemifts. This crumbled to pieces
between the fingers ; and when it was examined with
a magnifying glafs, it was found to confift of a num¬
ber of metallic globules, none of which were larger
than a pin head. i<si
4. The colour of this metal is a fteel gray. The Properties*
fpecific gravity is 17.6, or, according to others, 17.22.
It is one of the hardeft of the metals. It is alfo one
of the moft infufible, requiring a temperature of 170°
Wedgwood. It cryftallizes on cooling.
5. When it is heated in the open air, it is readily Adlion of
converted into a yellow oxide, which afterwards, by a heat,
ftronger heat, becomes of a black colour, and then by
combining with a greater proportion of oxygen, it af-
fumes the charadler of an acid, namely the tungftic
acid, whofe properties and combinations with alkalies
and earths, have been already deferibed. t£.;,
6. There is no aftion between tungften and azote, of phof-
hydrogen or carbone. Tungften combines with phof-phorus,See.
phorus, forming a phofphuret, the properties of which
are unknowm. It alfo combines with fulphur, form¬
ing a fulphuret of a bluilh black colour, and which
may be cryftallized. There is no adlion between this
metal and fulphuric, nitric, or muriatic acids. It is
only adled on by nitro-muriatic acid at a boiling tem¬
perature, and nitrous gas is difengaged. Nothing
therefore is knowm of the combinations of tungften
with the other acids. ^554
7. This metal combines with the other metals, and Alloys,
forms alloys with them.
8. It is too little known, and has been produced in
too fmall quantity, to be able to afeertain any thing of
its ufes or applications.
Sect. III. Of Moltbdena and its Combinations.
I. The mineral called mo/ybdena, from which thisHiftory?
metal is extrafled, was analyzed by Scheele in I77^*
He found that it contained fulphur, and a fubftance
which he difeovered to be pofleffed of acid properties.
Previous to this time, this mineral had been confounded
with plumbago or black lead, which it refembles in
appearance. The acid which Scheele obtained from
this fubftance, Bergman conjectured was a metallic
oxide. Thefe experiments were repeated by Pelletier;
and he proved that molybdena was a peculiar metal
combined with fulphur, and that in all the different
proceffes the fulphur was feparated, and the metal oxi¬
dated. The metal has fince been called molybdena,
4 I 2 and
H E M I S T R Y.
620 C
Molybdena, and tbe mineral from rvliicli it is obtainedof
&-c’ molybdena.
2. Molybdena lias never been found, exilling in any
Characters but in the ftate of fulphuret, or in that of oxide,
of the ore. The fulphuret of molybdena, it has been obferved, was
long confounded with plumbago, or the carburet of iron.
It has, however, a lefs greafy feel, more brilliancy,
and inclining more to a blue colour. It ftains the
fingers lefs than carburet of iron, and leaves a bluifh
trace on paper. It is difficult to reduce it to powder,
on account of the elafticity of the plates or fcales of
which it is compofed. The fulphuret of molybdena,
too, becomes electric by friction. When the fulphu¬
ret of molybdena is treated rvith the blow-pipe, it ex¬
hales fulphur, which is detected by its odour, and a
white vapour which is condenfed on cold bodies in the
form of plates or cryftallized needles, of a yellowifh
1557 colour, but which become blue by the contaft of the
Properties interior flame. Molybdena has only been obtained in
ofjthe :n£' black, friable, agglutinated maffes, which have fome
metallic brilliancy \ and when broken, exhibit fmall
round grains, of a grayilh brilliant appearance. The
fpecific gravity is about 7, and it is extremely infu-
fible ; but fince the experiments of Dr Hielm, which
were made in 1781, this metal has been procured in
fuch fmall quantity, that its charafteriftic metallic
1558 properties have not been afeertained.
Action of 3. When molybdena is expofed to a high tempera-
ticat. ture ;n conta$; with air, it is converted into a white
oxide, which fublimes and cryftallizes in the form of
brilliant needles. This oxide has acid properties.
When it is heated with combuftible bodies, it affumes
a blui'h colour, with little brilliancy, as it approaches
to the metallic ftate. According to Mr Hatchet, who
made a fet of experiments on the compound of this
acid with lead, the molybdate of lead, molybdena
when it is not in the metallic ftate, appears to fuffer
four degrees of oxigenation. The firft is the black
oxide, which contains the fmalleft proportion of oxy¬
gen. This oxide is obtained by expofing to heat in a
1559 crucible, a mixture of molybdic acid and charcoal in
t)xides. powder. A black mafs remains, which is the oxide.
The fecond is the blue oxide, which may be obtained
by the fame procefs, but it muft not be continued fo
long. The third is the green oxide, which feems to
Is6o be intermediate between an oxide and acid. Mr Hat-
Acids. diet propofes to call it molybdous acid. The fourth
degree of oxidation is the molybdic acid itfelf, which
* Phil. has at firft a white colour ; but wffien it is fufed and
'Tranf. fublimed, is converted into a yellow colour. The
I790- properties of this acid and fome of its combinations
have been already deferibed*.
Adh'onof 4- Molybdena combines with phofphorus ; but the
phofphorus. properties of this phofphuret are not known. It alfo
combines readily with fulphur, and returns to the ftate
of fulphuret of molybdena, in which it has only been
1.^2 found native.
Of acids. 5. Motybdena enters into combination with the
Is(j3 acids, forming with them peculiar falts.
Of alkaiie?. 6. The alkalies have the property of diffblving
molybdena, and of promoting its oxidation. With the
affiftance of heat the alkalies form with the fulphuret
of molybdena, an alkaline fulphuret which holds the
naetal in folution,.
7. Molybdena enters into combination with the me-Chromium,
tals, and forms alloys with them.
I. Salts of Molybdena.
1. Sulphate of Molybdena.
Sulphuric acid, with the affiftance of heat, diffolves
molybdic acid, and affords a colourlefs folution ; but
when it is cold, it becomes of a deep blue. But
neither this nor any other of the falts of molybdena
feem difpofed to cryftallize.
2. Nitrate of Molybdena.
Nitric acid converts the oxides of molybdena into
molybdic acid, by giving up its oxygen.
3. Muriate of Molybdena.
Muriatic acid, when boiled with the oxide of mo¬
lybdena, affords a folution of a deep blue colour,, and
there is formed a blue precipitate. •
4. Fluate of Molybdena.
Fluoric acid forms a compound with the oxides of
molybdena. The folution is of a greenifh yellow co¬
lour, wffien it is hot 5 but wffien it is evaporated to dry-
nefs, it becomes of a greeniffi blue.
5. Phofphate of Molybdena.
The oxide of molybdena is diffolved by phofpho-
ric acid, with the affittance of heat, and a folution of
a blue colour is obtained.
6. Acetate of Molybdena,
7. Oxalate of Molybdena,
8. Tartrate of Molybdena,
9. Benzoate of Molybdena.
All thefe falts in folution are of a blue colour, and
when evaporated to drynefs", afford a blue powder.
They are formed by digefting the Several acids with
the oxides of molybdena.
Sect. I\'. Of Chromium and its Combinations.
1. This metal wras difeovered by Vauquelin in 1797, . *5%
in a mineral called the red lead ore of Siberia. This Hlftory*
ore had been formerly analyzed by feveral chemifts,
and even by Vauquelin himfelf; but their refults of the
nature of its compofition only agreed, that lead wTas
one of its conftituent parts. Vauquelin by his laft ana-
lyfis found that it contained lead, combined with the
new^ acid, of which the bafis is a metal.
2. The procefs which he followed was the following: ^
He boiled one part of the red lead ore of Siberia with the ore.
two of carbonate of potaffi, in 200 parts of water. The
potafh combined with the new acid, wffiile the carbo¬
nic acid united to the lead. The carbonate of lead,
precipitated to the bottom in the form of a white pow'-
der, and the new’ fait remained in folution. By adding
nitric acid, the new fait was decompofed j the acid
combining with the potafli. This mineral is complete¬
ly diffolved in muriatic acid. The folution affumes a
deep green colour, and by evaporation affords muriate
of lead. The fine green colour is owing to the oxida,
of the new metal having been deprived of part of its.
oxygen
*564
Alloys.
C H E M I S T R Y.
621
Colurtl-
biuai, See.
IS6/
Reaibn of
the name
of the me¬
tal.
1568
Properties.
I569
Fouiia in
different
minerals.
157®
Oxides.
1.571
A&ion of
acids.
'SI*
Hiftory.
*573
Characters
ef the ore.
oxygen by the muriatic acid, and being thus converted
from an orange red to a green.
3. The acid which is obtained by the firif procefs,
and the oxide by the fecond, being ftrongly heated
with charcoal in a crucible, afforded a metal different
from any other formerly known. To this metal the
name of chromium was given, from the Greek word
on account of the remarkable property which it
poifelfes of communicating colour to all its faline com¬
binations.
4. The metal which was obtained, is of a grayifli
white colour, very hard and brittle, and extremely dif¬
ficult of fufion \ but the finall quantity which has been
hitherto obtained, precludes chemitls from afeertaining
its properties.
5. This fubftance has been found in four different
minerals, exilting in two flatesin the (late of green
oxide, combined with the oxide of lead, and in the
fame ftate in the emerald } and, in the flate of acid,
combined with the oxide of lead in the red-lead ore of
Siberia, and alfo in the fpinel ruby. It has alfo been
difeovered in the flate of chromic acid, combined with
iron, forming a chromate of iron. It has alfo been
difeovered in France.
6. Chromium, therefore,combines with oxygen in two
different proportions', the green oxide, and the yellow,
or the chromic acid. It is this acid which exifts in
the red-lead ore. When it is feparated from the lead,
it is in the form of povvder, of an orange yellow colour,
and is foluble in water. Its other properties have been
already examined. The green oxide is prepared by
expofing the latter to heat in clofe velfels. T. he chro¬
mic acid is partially decompofed ; part of the oxygen
is driven off, and the green oxide remains behind.
Another oxide alfo, it is faid, which is intermediate
between chromic acid and the green oxide, has been
* obtained.
7. Little is known of the a6fion of acids on this me¬
tal; but in the few experiments which have been made,
it appears, that it undergoes no change by means of
fulphuric and muriatic acids. Nitric acid diflilled up¬
on it feveral times fucceffively, changes it into green
oxide, and at laft into chromic acid. The fame eftedl
is produced more rapidly by means of the nitromuria-
tic acid.
Sect. V. Of Columbium and its Combinations.
I. This metal was difeovered by Mr Hatchet, in the
year 1802, in a mineral, wdiich he found in the Britifh
Mufeum. This mineral had been fent along with fpe-
cimens of iron ores from Malfachufets in America, to
Sir Hans Sloane, in whofe catalogue it is deferibed as
a “ very heavy black ftone, with golden flreaks.”
Thefe llreaks, Mr Hatchet obferves, proved to be yel¬
low mica. This mineral is externally of a dark-brown-
ifh gray colour ; internally the fame, inclining to iron
gray. The longitudinal fra&ure is imperfeftly lamel-
lated ; the crofs frafture fhews a fine grain. The
luffre is vitreous, in feme parts inclining to the metal¬
lic. It is moderately hard, but very brittle. The co¬
lour of the powder is dark chocolate brown. The par¬
ticles are not attra&cd by the magnet. The fpecific
gravity is 5.918.
2:
2. In the analyfis of this mineral, Mr Hatchet dif- Colum-
covered, that it confifts of one part of oxide of iron, hlam, See.
and three parts of a white-coloured fubflance, wTich I£._4
exhibited the properties of an acid. This acid, under Anaiytis.
the name of columbic acid, with its combinations with the
alkalies and earths, has bepn already deferibed. Ha¬
ving found that it poifefied properties different from all
other acids, and alfo, that its bafe is metallic, he gave to
the metal the name of columbium. In the attempts
which Mr Hatchet made to reduce it to the metallic
Hate, even when it was expofed to a very ftrong heat
with charcoal, the oxide was only found in the Hate of
powder, of a black colour. From thefe experiments
it appeared, that this metal combines with oxygen in
different proportions, and thefe oxides are diftinguifhed
by different colours.
3. When the white oxide of this metal was added to
phofphoric acid in folution, and evaporated to drynefs,
the whole was put into a crucible, lined with charcoal,
and expofed to a ftrong heat for half an hour. The
inclofed matter had aflumed a dark brown, fpongy ap¬
pearance, w'hich had fume refemblance to the phofphu-
ret of titanium.
4. No fulphuret was obtained when it was mixed and
diftilled with fulphur.
5. Columbium combines with fome of the acids,
and forms falls, although few' of thefe have been ex¬
amined.
I. Salts of Columbium.
I. Sulphate of Columbium.
Boiling fulphuric acid forms a tranfparent colour-
lefs folution with columbic acid. When water is added
to this folution, it becomes turbid, affirming a milky
appearance ; and a white precipitate is gradually de-
pofited, which cracks as it becomes dry upon the filter,
and, from white, it changes to a lavender blue colour;
and, when completely dry, to a brownifh gray. It is
then infoluble in water, is femitranfparent, and breaks
with a vitreous fratlure. This precipitate obtained from
the fulphuric folution, by the addition of water, is a
fulphate of columbium.
2. Nitrate of Columbium.
The oxide of columbium feems to be perfectly info¬
luble, and remains unchanged in colour, when digefted
in boiling concentrated nitric acid.
3. Muriate of Columbium.
Columbic acid, when recently feparated from pot-
afTi, is foluble in boiling muriatic acid. This folution
may be confiderably diluted with water, without any
change being produced. When evaporated to drynefs,
it left a pale-yellow fubftance, infoluble in water, and
w'hich is dillolved with great difficulty, when it is again
digefted with muriatic acid.
4. Phofphate of Columbium.
A few drops of phofphoric acid being added to a part
of the folution of columbium in concentrated fulphuric
acid, at the end of about 1 2 hours converted the whole
into a white, opaque, ftiff jelly, which was infoluble
in water. When a fmall quantity of phofphoric acid
way
622
Titanium
&.C.
* Mi/.
cTranf.
1802.
p. 49.
. *575
Hiftory of
its difco-
very.
CHEMISTRY.
1576
Natural hi
Sory.
Analyfis of
its ore.
, was added to the muriatic folution of columbium, in
a few hours a white flocculent precipitate was form-
J ed * (a).
Sect. VI. Of Titanium and its Combinations.
1. This metal was difcovered in 1793 by Klaproth.
He obtained it from a mineral called redfchorl. In
this mineral he found the oxide of a metal different
from any other then known. Previous to this time,
indeed, the fame oxide had been difcovered by Mr
Gregor, in a black fand which is found in Menachan
in Cornwal. To this, from the place, he gave the
name of menachine, but he had not fucceeded in re¬
ducing it to the metallic date. Klaproth afterwards
analyzed the menachanite of Mr Gregor, and found that
it was precifely the fame as the oxide of the metal
which he difcovered in red fchorl. To this metal
he gave the name of titanium. The experiments
of Klaproth were afterwards repeated by Vauquelin
and Hecht in 1796. His refults were confirmed, and
they alfo fucceeded in reducing a fmall quantity of the
oxide to the metallic date.
2. This metal has been found only in the date of
oxide. Red fchorl condds entirely of this oxide. It
has been found in different countries, as in Spain,
France, and Hungary. This oxide is diffeminated in
the dne fpecimens of rock crydal which are brought
from Madagafcar, crydallized in long brilliant needles,
the form of the primitive crydal being a dx-dded
prifm with two-dded fummits ; that of the molecule
is a triangular prifm, with right-angled ifofceles bafes.
It is of a red colour of different diades. It is brittle,
but the fragments are fo hard as to fcratch glafs. The
fpecidc gravity is from 4.180104.246. The other mi¬
neral, to which Klaproth has given the name of titanite,
is compofed of oxide of titanium, dlica and lime, nearly
in equal proportions. Its fpecific gravity is 3.510.
3. Titanium was obtained by Vauquelin, by redu¬
cing the native red oxide. He mixed together 100
parts of this oxide with 50 of calcined borax, and 50
of charcoal, formed into a pade with oil ; and expoi'ed
the whole to the heat of a forge raifed to 1660 Wedg¬
wood. By this procefs he obtained a dark-coloured,
agglutinated mafs, having a brilliant appearance on Titanium,
the furface. ^cc• ^
4. Titanium obtained in this way is of a reddidi f
yellow colour, diining and brilliant on the lurface, and properties,
equally brilliant in fome of its internal cavities. Its
other properties, as it has been only procured in very
fmall quantity, have not been determined.
5. Titanium feems to be one of the mod infudble
metals known. When the red oxide is expofed to heat,
heat in a crucible, it lofes its ludre. By the adlion
of the blow-pipe it is deprived of its tranfparence, and
becomes of a grayidi white colour. On charcoal it
becomes dill more opaque, and of a date gray. The
artificial carbonate of titanium expofed to heat in a
crucible, lofes of its weight, becomes yellow,
and as it cools, refumes its white colour.
6. Titanium enters into combination with phofpho- Phofphure^,
rus, and forms with it a phofphuret. This was pre¬
pared by Mr Chenevix, by expofing a mixture of
phofphate of titanium, charcoal, and a little borax, in
a crucible, to a very drong heat. The phofphuret
which he obtained was in the form of a metallic but¬
ton, of a pale white colour, brittle and granular, and
infufible hy the aftion of the blow-pipe. Titanium
has not been combined with fulphur.
7. This metal enters into combination with the
acids, and forms falls with them. The affinities of
the oxides of titanium, as they have been afcertained
by Lampadius, are in the following order.-
Gallic acid,
Phofphoric,
Arfenic,
Oxalic,
Sulphuric,
^.Ur.iatic> f Ann. dc
Nunc, thim.
Acetic -f-. xxvi. 91.
8. In the experiments wffiich wrere made by Van-Alloys,
quelin and Hecht, to combine titanium with other
metals, they did not fucceed with filver, copper, lead,
or arfenic •, but they formed an infufible alloy with
iron, of a gray colour, interfperfed with yellow-co¬
loured, diining particles.
I. Salts
(a) Another metal has been more lately renounced by Ekeberg, which, in fome of its properties, feems to re-
i’emble columbium. He obtained this metal from two minerals ; to one of which he gave the name of tantalitet
which is of a blackidi gray colour, with fome metallic ludre, and fome appearance of crydallization. This mi¬
neral is very hard j the fpecific gravity is 7.953. When reduced to pow’der, it is of a brownidi gray colour,
and is not attradfed by the magnet. To the other mineral he gave the name oiyttrotanta/ite. It was found in
fmall infulated maffes, in veins of feldfpar, and black mica. The fradlure of this mineral is granular, of a gray
metallic appearance, and may be fcratched, although with difficulty, with a knife. It is not attracted by the
magnet. The fpecific gravity is 5.13. From thefe minerals this chemid extradled a fubdance, which he con¬
cluded to be a peculiar metal in the date of oxide, having the appearance of a white powder. The following
are the properties which he afcertained.
1. It is not folub^; in any of the acids. 2. The alkalies attradl and diffolve a confiderable quantity of this
fubdance, which may afterwards be precipitated by means of the acids. 3. The whole oxide of this metal un¬
dergoes no change of colour by the adlion of heat. 4. Its fpecific gravity when it has been expofed to a red-
heat is 6.5. 5. It fufes with phofphate of foda, and borax, without communicating to them any colour. 6. The
oxide of this metal, heated with charcoal powder, is reduced to the metallic date, exhibits a brilliant fra&ure, of
a dark gray colour. 7. It is again converted into a whit* powder by the adlion of the acids. The other pro- * Ann. dt
perties of this fubdance have not been detailed *. To this metal Ekeberg has given the name of tantalum. c,jim
& 0 xliii.p.
CHEMISTRY.
I. Salts of Titanium,
i. Sulphate of Titanium.
According to the experiments of Klaproth, fulphu-
ric acid has no adlion on the native red oxide of ti¬
tanium from Hungary : but this acid is found to dif-
folve the carbonate of titanium with efTervefcence 5 and
when this folution is evaporated, the red oxide is con¬
verted into a white, opaque, gelatinous mafs. This
was the refult of Klaproth’s experiment. In thofe of
Vauquelin and Hecht, fulphu ic acid being boiled
with carbonate of titanium, affumed a milky appear¬
ance, and there were formed white, light flakes, which
were diffolved by a ftronger heat ; the fluid became
tranfparent, but did not aflfoid cryftals.
2. Nitrate of Titanium.
Nitric acid has fcarcely any perceptible a&ion on
titanium, but it combines with the carbonate, and
forms a tranfparent folution, which affumes an oily ap¬
pearance in the air, and affords tranfparent cryftals in
the form of elongated rhombs, having the oppofite
angles truncated, fo as to reprefent hexagonal tables.
But according to Vauquelin and Hecht, when they
heated a mixture of nitric acid with carbonate of ti¬
tanium, nitrous gas was difengaged, and the liquid re¬
mained milky. Sugar added to the mixture caufes a
precipitate of the oxide, of a whiter colour than the
carbonate ; and if the nitric acid be employed diluted,
the oxide of titanium is diffblved, but the folution be¬
comes turbid by means of heat, and thus the addition
of caloric oppofes the combination of this oxide with
nitric acid, by oxidating it in a higher degree than
what is foluble in this acid.
3. Muriate of Titanium.
The carbonate of titanium is foluble in muriatic
acid *, and according to Klaproth, the folution affords a
yellowifh, tranfparent jelly, which contains numerous
tranfparent, cubic cryftals. \ auquelin and Hecht
found, that the carbonate of titanium is diifolved with
effervefcence in concentrated muriatic acid ; and the
folution affumes a deep yellow colour, when it is made
without the afliftance of heat. When It wms heated,
it was reduced to a flaky mafs, which was neither re-
diffolved by water, nor by new' additions of the acid.
A fimilar folution which was not heated remained
tranfparent ■, but when this folution was expofed to a
temperature of about \^o0, it was converted into a
yellow, tranfparent jelly, of an acid and very aftrin-
gent tafte, which by cooling, depofited a great num¬
ber of fmall cryftals which efflorefced in the air.
When this folution was boiled, oxymuriatic acid gas
was difengaged, the oxide was precipitated, and is no
longer foluble in muriatic acid, till it is boiled for a
long time with nitric acid ; from which it appears,
that the oxide of titanium muft have a great proportion
of oxygen, to comb’ne with muriatic acid, and in this
ftate it can only combine with it in the cold, becaufe
when it is expofed to heat, the acid carries off a por¬
tion of its oxygen, which renders it infoluole. . I he
oxide of titanium, feparated from muriatic acid by
the adlion of the blowT-pipe, alfumes a beautiful orange-
yellow7 colour.
Titarnun),
See.
1583
Salts.
623
Uranium,
4. Carbonate of Titanium. &c.
One part of the red oxide of titanium, and five 1 ^s.; ^
parts of carbonate of potaih, expofed to a red heat in Prepara-
a crucible, were foon fufed, and formed a folid mafs tion.
of a whitifh gray colour, wuth fmall needle-form cry¬
ftals on the furface. When this was reduced to pow¬
der, and waflied with wrarm water, there was depofit¬
ed a light wfliite powder, which was found to be car¬
bonate of titanium. The arfenic and phofphoric acids
caufe a white precipitate of the oxide of titanium from
its folution in acids. A fimilar precipitate is produced
by oxalic and tartaric acids 5 but it is inftantly re-dif-
folved, and the folution recovers its tranfparency.
The oxide of titanium is precipitated from its folu-Salts of ti=
tion in acids *, 1. By carbonate of potaih, in the formtaniumde-
of a white flaky matter, and by ammonia in the fame comP°^ed’
way. 2. Prufliate ©f potafti caufes a copious precipi¬
tate of a mixed colour of green and brown. 3. Infu-
fion of nut-galls produces a very voluminous precipi¬
tate, of a reddiih brown colour $ and if the folution
be not too much diluted with water, it coagulates like
blood. A rod of tin introduced into a fmall bottle
with a folution of this oxide in muriatic acid, caufed
in a few minutes a pale role colour, in that part of the
folution near the rod. This colour foon changed to a
beautiful ruby. A rod of zinc firft produced a violet
colour, and afterrvards that of indigo. 4. Sulphuret
of ammonia combined with this folution, produced a
pale green colour, and a precipitate of a bluifti
green.
Sect. VII. Of Uranium and its Combinations.
1585
1. This metal was difeovered by Klaproth in the Difcovery.
year 1789. It was then announced as a metal more
difficult to be reduced than manganefe, externally of
a gray colour, and internally of a clear brown, of con-
fiderable luftre, and middling hardnefs •, that it might
be fcratched and filed, and that its oxide gives a deep
orange colour to porcelain.
2. It has been obtained from three different mine-Natural hi«
rals. The firft is in the ftate of fulphuret, of a black- Rory.
ifti colour, and of a fluffing fraflure, and fometimes
lamellated. This has been called pilch blende. The
fpecific gravity is from 6.37 to 7.50. In this ftate it
is fometimes combined with iron and fulphurated lead.
The uranium is in the metallic ftate. The fecond ore
from which this metal is obtained, is the native oxide
of uranium. It is always in the ftate of yellow pow¬
der, on the furface of the fulphuret. The fpecific
gravity is 3.24. When it is of a pure yellow colour,
it is then a pure oxide. The third ore of the metal is
the native carbonate of uranium. Of this there are
two diftinft varieties, the one of a pale green, and
fometimes of a filvery white colour. This contains
but a fmall quantity of the oxide of copper, and is
very rare. The other is of a fluffing deep green,
which is the green mica or glimmer of mineralogifts.
Klaproth fuppofed that it contained an oxide of ura¬
nium, mixed with the oxide of copper 3 but it has
been fince difeovered to have carbonic acid in its
compofition. It is cryftallized in fmall fquare plates,
and fometimes, though rarely, in complete oftahe-
drons,
3. The
624 C H E M
Uranium, g. ^The proc^fs by wliicb Klaproth reduced this me-
, c^c, . tal, is the following. He mixed the yellow oxide of
IjS8 uranium, precipitated from its folutions by an alkali,
Analyfis of with linfeed oil, in the form of a pafle, and this being
the ore. expofed to a llrong heat, there remained a black
powder, which had loft rather more than one-fourth
of its weight. It was then expofed to the heat of a
porcelain furnace, in a clofe crucible, and the oxide
was afterwards found in a coherent mafs, but friable
under the fingers, and reduced to a black ftiining
powder. It decompofed nitric acid with effervefcence.
This black powder covered with calcined borax, was
for the fecond time expofed to a ftill ftronger heat, by
which a metallic mafs was obtained, confifting of very
Imall globules adhering together.
Properties. 4. The colour of uranium is of a dark gray, and
internally of a pale brown. It has little brilliancy, on
account of the fpongy mafs, in tvhich ftate it was ob¬
tained. It may be fcratched with a knife, and is ex-
tremely infufible. The fpecific gravity is 6.440.
Adtion of 5. When uranium is expofed to a red heat in the
heat. open air, or w’hen it is afted on by the blowpipe, it
undergoes no change. The yellow oxide of uranium
does not melt. It acquires a browniih gray colour
when it is long heated in the air, but it has not been
afcertainedwhether it gains or lofes oxygen.
6. The oxide of uranium is reduced by means of
charcoal, when it is expofed to heat. Little is known
of the combination of uranium with phofphorus 5 but
when the oxide was treated w'ith blood, and a ftrong
heat applied, an acrid bitter mafs w’as obtained, which
-was fuppofed to owe its fufibility to the phofphorus
which it contained.
7. Uranium has not been artificially combined with
fulphur, but it is not improbable that fuch a combination
might take place, fince it is found native in this ftate.
Of the alloys of uranium with other metals nothing is
yet known.
1591
Salts. I. Salts of Uranium.
1. Sulphate of Uranium.
The yellow oxide of uranium is readily diflblved in
diluted fulphuric acid j and the folution affords, by
evaporation, a fait of a yellow' colour, in the form of
finall prifms. This fulphate of uranium is different
from all other metallic falts yet known, in colour, form,
and other properties.
2. Nitrate of Uranium.
Nitric acid diffolves with equal facility the oxide of
uranium. The folution being flowdy evaporated,
yields large cryftals in regular hexagonal tables, of a
yellowilh green colour. The cryftals of nitrate of
I S T R Y.
uranium are the moft beautiful of all the metallic Cobalt,
falts.
3. Muriate of Uranium.
Muriatic acid alfo diffolves the oxide of uranium,
and furnifties fmall yellowilh cryftals, which arc deli-
quefcent in the air.
4. Fluate of Uranium.
Fluoric acid combines with the oxide of uranium, and
forms with it a cryftallized fait, which is not altered
by expofure to the air.
5. Phofphate of Uranium.
Phofphoric acid enters into combination with the ox¬
ide of uranium, and forms with it yellowilh white flakes,
which are very little foluble in water.
6. Arfeniate of Uranium.
Arfenic acid may be combined with uranium, by
decompofing the nitrate by means of an alkali. A pre¬
cipitate is obtained of a yellowifti powder, which is the
arfeniate of uranium.
7. Molybdate of Uranium.
In the fame way molybdate of uranium may be
obtained by adding a folution of molybdate of potafli
to the nitrate of uranium. It is obtained in the form
of pow'der.
8. Acetate of Uranium.
The oxide of uranium is foluble in concentrated ace¬
tic acid, with the afliftance of heat ; and beautiful yel¬
low cryftals are obtained, in the form of long, flender,
tranfparent, four-fided prifms, terminated by four-fided
pyramids.
The folutions of the oxide of uranium in acids are
precipitated by the alkaline fulphurets, of a browniih qon of the"
yellow, and their futface is covered at the fame time falts of u-
with a gray metallic pellicle. The fixed alkalies pre-ranium.
cipitate from their folutions an oxide of uranium, of an
orange yellow colour ; ammonia occafions a precipitate
of a bright yellow ; and the alkaline carbonates throw
dowm a carbonate of uranium of a whitifh yellow,
which is rediffolved in an excels of alkali. The infufion
of nut-galls thrown into one of thefe folutions, the ex-
cefs of whofe acid has been taken up by an alkali, pro¬
duces a chocolate brown precipitate. Zinc, iron, and
tin, introduced into thefe folutions, produce no change
of colour, either in the cold or by heat.
Sect. VIII. Of Cobalt and its Combinations.
1. The mineral called cobalt or cobolt, 00 feems to„.
7 v y , Hiftory.
have
(b) The following curious information from Beckmann, with regard to the difcovery of this mineral will, we
doubt not, prove interefting to the reader. “ About the end of the 15th century, cobalt appears to have been dug up
in great quantity in the mines on the borders of Saxony and Bohemia, difcovered not long before that period.
As it was not known at firft to what ufe it could be applied, it was thrown afide as a ufelefs mineral. The
miners had an averfion to it, not only becaufe it gave them much fruitlefs labour, but becaufe it often proved pre¬
judicial to their health by the arfenical particles with which it was combined ; and it appears even that the mineralo-
gical name cobalt then firft took its rife. At any rate, I have never met with it before the beginning of the
sixteenth century j and Mathefius and Agricola feem to have fitft ufed it in their writings. Frifch derives it
from
C H E M
Cobalt, have been firfl: employed to give a blue colour to glafs
, &-c‘ after the middle of the 16th century but it was not
v till about the year 1732, that cobalt was diftinguilh-
ed as a peculiar metal by Brandt, a Swedifh chemifl,
who extrafted it from its ore, and examined fome of
its properties. In 1761 Lehman gave a particular ac¬
count of the nature and properties of this fubftance;
but his refearches were chiefly limited to the mineral
in the ftate of ore. Bergman afterwards examined
this metal, and pointed out the difference between it
and nickel, manganefe, and iron. The nature of it has
been more lately inveftigated by Talfaert and Thenard,
and fome other French chemifts.
Ores! 2- Cobalt has never been found in nature in a ftate
' of purity. It is either alloyed with arfenic, both me¬
tals being in the metallic ftate •, or it is combined with
fulphur and arfenic, or in the ftate of oxide, or form¬
ing a fait with arfenic acid. 1. In the firft ftate when
it is alloyed with arfenic, it is of a gray or whitifh ap¬
pearance, with fome degree of brilliancy. The fpeci-
fic gravity is 7.72. It is fometimes cryftallized in cubes,
or odlahedrons. When fmall fragments of this mine¬
ral are expofed to the aiSion of the blow-pipe, or even
to the flame of a candle, they give out a garlic fmell.
2. The combination of fulphur and arfenic with cobalt
is denominated gray cobalt ore. The fpecific gravity
is from 6.33 to 6.45. The ftru&ure is lamellated, and
when it is heated, it emits no garlic fmell. It cryftal-
lizes in oftahedrons, dodecahedrons, and fome other
forms refembling the fulphuret of iron, with which it
is frequently combined. 3. The third fpecies of co¬
balt ore, is the oxide. It is found in black, friable
mafles, or in the ftate of a black efflorefcence, which foils
the fingers. This is a pure oxide of cobalt. 4. The
fourth fpecies is the arfeniate of cobalt, which has been
diftinguilbed by the names of Jlowers of cobalt, cobalt
bloom. It is of a peach-bloffom colour, fometimes in
the ftate of efflorefcence, fometimes in the form of fmall
needles of a deep colour, which remains even after they
are reduced to powder, and fometimes in four-fided
prifms terminated by two-fided fummits. When it is
placed on hot coals, it gives out a ftrong garlic fmell,
x .(j- lofes its colour, and becomes black.
Analyfis of 3. To procure the pure metal from the ores of co-
the ores. bait, the oxide in the ftate of black powder, after be¬
ing roafted, is mixed with three times its own wreight
of black flux and a little common fait, put into a cru¬
cible lined with charcoal, and expofed to a forge heat.
When the fufion is completed, the crucible is to be
■flightly agitated, to colledl together the metallic glo¬
bules into one mafs. Sometimes two metallic buttons
Vol. V. Part II.
I S T R Y.
are found under the vitreous fcorim. The cobalt oc¬
cupies the upper part, and the bifmuth being heavieft,
is loweft. In this ftate the cobalt is almoft always
combined with a fmall portion of arfenic, nickel, or
iron. But if the cryftallized gray oxide of cobalt has
been employed, the metal is obtained very pure, by
the above procefs ; and when the ore is rich, it yields
from 60 to 80 per cent.
By a different procefs, cobalt may be obtained in
the metallic ftate, which confifts in treating the ore
with nitric acid, which oxidates and diffolves both the
cobalt and the iron. Thefe oxides are precipitated
by carbonate of foda, and well walhed with water.
They may be feparated by means of nitric acid, which
diffoives the oxide of cobalt, without touching that of
the iron.
4. Cobalt is of a gray colour, inclining to red, and Properties
of a very fine granulated texture. It is very brittle, °fcoba!t*
fo that it is eafily reduced to a fine powder, which is
of a gray colour, and with little brilliancy. The fpe¬
cific gravity, according to Bergman, is 7.700 j ac¬
cording to others, it is from 7.811 to 8.5384. 1597
5. Cobalt is one of the moil infufible metals, requir- Action of
ing a temperature equal to 130° Wedgwood. It be-heat*
comes red before it melts. When it is flowly cooled,
and by pouring out a part of the fluid when it becomes
folid at the edges, the cavity is found lined with prif-
matic cryftals. The fame cryftallization may be effe£l-
ed by inclining the crucible at the moment the furface
becomes folid. 1599
6. When cobalt is expofed to a red heat in an open Oxidation,
veffel, it firft lofes its colour and its brilliancy, becomes
of a deep gray colour, and then paffes to a black, or
an intenfe blue. With a ftill more violent heat, this
laft oxide melts into a bluilh black glafs. It appears
from the experiments of Thenard, that cobalt combines
with different proportions of oxygen, forming different
oxides. When a folution of cobalt in acids is preci¬
pitated by an alkali} the precipitate which is formed
is firft of a lilach colour, and with an excels of bafe it
becomes fucceflively blue and olive, and at laft by dry¬
ing it becomes entirely black. Thefe different chan¬
ges depend on the different proportions of oxygen with
which it combines.
He precipitated a folution of cobalt by pure potafli.
The oxide collefted on a filter, w7as blue, and when ex¬
pofed to the air it became of an olive colour’, and when
walhed with oxymuriatic acid, it changed from green
to brown, and from this fhade to the deepeft black.
The black oxide diffolved with effervefcence in muria-
atic acid $ oxymuriatic acid gas was emitted in great
4 K abundance.
625
Cobalt,
&c.
from the Bohemian word 'bow, which fignifies metal ; but the conje&ure that it was formed from cobalus, which
was the name of a fpirit that, according to the fuperftitious notions of the times, haunted mines, deftroyed the
labours of the miners, and often gave them a great deal of unneceffary trouble, is more probable ; and there is
reafon to think that the latter is borrowed from the Greek. The miners, perhaps, gave this name to the mineral
out of joke, becaufe it thwarted them as much as the fuppofed fpirit, by exciting falfe hopes, and rendering their
labour often fruitlefs. It was once cuftomary, therefore, to introduce into the church fervice a prayer that God
would preferve miners and their works from bobolts and fpirits.”
“ Mathefius, in his tenth fermon, p. 501, where he (peaks of the cadmiafoffdis, fays: ‘ Ye miners call it
hobolt; the Germans call the black devil and the old devil’s whores and hags old and black kobel, which by their
witchcraft do injury to people and to their cattle.’—Whether the devil, therefore, and his hags gave this name
to cobalt, or cobalt gave its name to witches, it is a poifonous and noxious metal.”
1599
Oxides,
four.
Ann. de
Cbim. xlii.
310—215.
1600
Phofphu-
ret.
i6or
gulphuret.
1602
Salts.
G H E M I
abundance, and when tbe muriatic acid was concen¬
trated, the folution was of a green colour, which in the
fpace of 24 hours became purple. When the acid was
diluted, it became inftantly red. The oxide is foluble
in fulphuric and nitric acids, and the folution is of a red
colour, accompanied with the evolution of bubbles,
which feem to be oxygen gas.
The brown and coloured oxides produce with ful¬
phuric, nitric, and muriatic acids, limilar effedts with
the black oxide. With muriatic acid they both give
out oxymuriatic acid, and form a folution of a green co¬
lour, which in time paffes to a purple ) or, if the acid
be diluted with water, it becomes inftantly red. The
olive-coloured oxide is prepared by pouring potaftr into
a folution of cobalt. There is formed a blue precipi¬
tate, which expofed to the air becomes green. If this
oxide be treated with diluted muriatic acid, oxymuria¬
tic acid is obtained with a flight degree of heat, and
the folution becomes more and more red, as this acid
is difcngaged , fo that the blue oxide combines with the
oxygen of the air.
The blue oxide of cobalt, Thenard thinks, is moft
conveniently obtained by calcining the black oxide for
half an hour in a cherry-red heat. It affumes a blue
colour, by being deprived of part of its oxygen. This
oxide diflblves in acids, without the difengagement of
any gas. Its folution in concentrated muriatic acid is
green, but if the acid be diluted with water, it is red.
Thenard concludes from his experiments, that there are
four different oxides of cobalt; the blue, the olive, the
brown, and the black ; although he fuppofes that the
brown may be a mixture of the olive and black oxides *.
7. There is no aftion between azote, hydrogen, or
carbone, and cobalt.
8. Phofphorus enters into combination with cobalt,
by projecting bits of phofphorus on fmall pieces of co¬
balt, red-hot, in a crucible. The metal is inftantly
fufed, and it abforbs about of is weight of phofpho¬
rus. A cruft is formed at the fame time on the fur-
face, of a violet-red colour. This phofphuret of co¬
balt has a metallic luftre, is of a whiter colour than
the metal itfelf. and is more brittle. It lofes its bril¬
liancy in the air; and by the aCtion of the blow-pipe,
phofphorus is difengaged from the metallic globule,
and inflames on the furface. There remains behind a
vitreous globule of a deep blue colour.
9 Sulphur combines with difficulty with cobalt,
but the compound may be formed by the aid of the
alkalies. This metal is foluble in the alkaline fulphu-
rets, and the refult is a fulphuret of cobalt, of a yel-
lowifh white colour, which is only decompofed by means
of the acids.
10. Cobalt enters into combination with the acids,
and forms falts. It forms alloys alfo with moft of the
metals. The order of the affinities of cobalt and its
oxides, according to Bergman, is the following:
Cobalt.
Oxide of Cobalt.
Iron,
Nickel,
Arfenic,
Copper,
Gold,
Platina,
Oxalic acid,
Muriatic,
Sulphuric,
Tartaric,
Nitric,
Phofphoric,
S T R Y.
Cobalt.
Tin,
Antimony,
Zinc,
Phofphorus,
Sulphur,
I. Salts of Cobalt.
I. Sulphate of Cobalt. 1603
1. Concentrated and boiling fulphuric acid is
compofed by cobalt, with the evolution of fulphurous
acid gas. A thick, grayiffi mafs, inclining to red, is
formed. Water diffolves the fulphate of cobalt, and
affords a grayifh coloured liquid.
2. The fulphate of cobalt cryftallizes in fmall nee¬
dles, or in four-fided rhomboidal prifms, terminated „
by two-fided fummits. It is of a reddiffi colour, and roper
is foluble in 24 parts of water. It is decompofed by
heat, and there remains behind the black oxide of co¬
balt. By the a&ion of the blow-pipe it fwells up
with effervefcence. The alkalies alfo decompofe it,
by precipitating a reddiffi yellow oxide. One hun¬
dred parts of cobalt furniffi 140 parts of this precipi¬
tate by pure alkalies ; but when the precipitation is
effe&ed by means of the alkaline carbonates, 160 parts
are obtained.
, 2. Nitrate of Cobalt.
1605
1. Nitric acid combines with cobalt, with the af-Prepara-
fiftance of a moderate heat. Nitrous gas is difengaged, tion.
the metal is oxidated, and is diffolved in the acid.
The folution is of a fleffi-red colour, but when it is
concentrated, of a brown colour. By evaporation it
affords fmall reddiffi coloured prifmatic cryftals, which
are deliquefcent in the air, and which being placed on
red-hot burning coals, fwell up, and are decompofed,
leaving behind a deep red oxide.
2. It is by the precipitation of this fait, that the
oxide of cobalt is obtained for the purpofe of enamels,
and for giving a colour to porcelain. When the ox¬
ide is precipitated by means of an alkali, it is re-dif-
folved when the alkali is added in excefs.
3. Nitrate of Ammonia and Cobalt.
This triple fait was formed by Thenard by adding
to a folution of cobalt in nitric acid, ammonia in ex¬
cefs. No precipitate is obtained. This folution be¬
ing filtered and evaporated to drynefs, and the refidue
being diffolved in water, and again evaporated, yield¬
ed, on cooling, regular cubic cryftals of a red coiour,
and of a pungent tafte. They were not changed by
expofure to atmofpheric air. Being calcined in a cru¬
cible, they burned like nitrate of ammonia, with a vi¬
vid, yellowiffi white flame. The refidue was a black
fubftance, which had all the properties of cobalt.
The folution of this fait in water is not precipitated by
any of the alkalies pr earths. It is ftill more readily
decompofed by fulphurated hydrogen, or the hydro-
fulphurets. When it is boiled with potafli, ammonia
Oxide of Cobalt.
Fluoric,
Saclaftic,
Succinic,
Citric,
Laftic,
Acetic,
Arfenic,
Boracic,
Pruffic,
Carbonic.
Cobalt,
&c.
C H E M
Cobalt, Is difengaged ; tKe oxide of cobalt is precipitated, and
  a nitrate of potafb is formed *.
* Ann. dt
Chim.
xlii. 215.
1607
Prepara¬
tion.
1608
Sympathe.
tic ink.
Tiieories.
i5i&
Another
procefs.
4. Muriate of Cobalt.
1. Muriatic acid has no effe£t on cobalt in the cold *,
but a fmall quantity is dilfolved with the afliftance of
heat. But the black oxide of cobalt is readily diflblv-
ed in muriatic acid. The folution is accompanied with
effervefcence, and the difengagement of oxymuriatic
acid gas. When this folution is concentrated by eva¬
poration, it becomes of a fine green colour, which
changes to red when it is diluted with water. By
farther evaporation it is cryftallized, and affords fmall
deliquefcent cryftals of muriate of cobalt in the form
of needles.
2. When thefe cryftals are diflblved in water, and
fo diluted that the folution is nearly colourlefs, cha-
ra&ers marked with it on paper difappear entirely ;
but when heated, aflume a fine green colour. This
folution was one of the firft known fympathetic inks.
In making experiments with this folution, the charac¬
ters are written on paper, or, that the experiment may
be more amufing, a landfcape is drawn with a pen¬
cil, reprefenting the verdure of fummer on a winter
fcene. Thofe parts of the pifture in which the fym¬
pathetic ink has been ufed, are invifible in the cold ;
but when it is moderately heated, they become of a
fine green colour, changing from the winter to the
fummer fcene. When it is removed to the cold, the
colour again difappears, and if too much heat be not
applied, the fame change may be frequently repeated.
When too much heated, the blue colour is converted
to a brown, wdiich becomes permanent.
3. Various theories have been propofed to account
for this remarkable change. According to fome, it
is owing to the moifture of the atmofphere being ab-
forbed that the colour difappears ; and when this is
driven off by heat, it is reftored. But to this opinion
it has been objedled, that the fame effe£t is produced,
when paper, on which charafters have been written
with this folution, is entirely excluded from the at¬
mofphere, by being introduced into clofe veflels. Ac¬
cording to others, the fympathetic eftefl: of this folu¬
tion depends on the iron which is combined with the
cobalt. Some fuppofe that the concentration of the
folution, which takes place by the affion of heat, is
the caufe of the appearance of the colour ; and its di¬
lution, by abforbing moifture from the atmofphere,
the caufe of its difappearance •, while others are of
opinion that it is partially deprived of its oxygen by
being heated, and abforbs it again in the cold, when
the colour vanifhes.
This fympathetic ink may be eafily prepared, by
diffolving the zaffre of commerce in nitro-muriatic
acid.
5. Fluate of Cobalt.
Fluoric acid diffolves the oxide of cobalt, and forms
with it a yellow-coloured gelatinous folution ; or, by
careful evaporation, it affords cryftals, W’hich are fluate
of cobalt.
6. Borate of Cobalt.
Boracic acid has no action on cobalt j but it com-
I S T R ¥.
bines with the oxide, by mixing a folution of nitrate
of cobalt with a folution of borax.
7. Phofphate of Cobalt.
Phofphoric acid diffolves the oxide of cobalt, and
forms with it a reddifh-coloured turbid folution,
which affords a precipitate when the acid is fatu-
rated.
8. Carbonate of Cobalt.
This fait is formed by precipitating cobalt from its
folutions in acids, by means of alkaline carbonates.
One hundred parts of cobalt, which afford only 140
of precipitate by means of the pure alkalies, yield
160 parts, when the precipitate is effefted by carbo¬
nate of foda.
9. Arfeniate of Cobalt.
This fait is formed by combining the nitrate of co
bait with the arfeniate of potaih or of foda. It is fome-
times found native, and it exhibits the deepeft and moft
beautiful red of all the falts of cobalt.
10. Tungftate of Cobalt, "1
11. Molybdate of Cobalt, /
12. Chromate of Cobalt, f unknown.
13. Columbate of Cobalt, J
14. Acetate of Cobalt.
This fait is readily formed, by diffolving the oxide
of cobalt in acetic acid. It does not yield cryftals by
evaporation, but is deliquefcent in the air. It affumes
a blue colour when it is heated, but is red in the
cold, fo that it forms a fympathetic ink.
15. Oxalate of Cobalt.
This fait may be formed by precipitating the oxide
of cobalt from its folution in acids, by means of oxalic
acid. The precipitate, when it is dried, is in the
form of a red powder, which is infoluble in w ater, but
may be diffolved in excefs of oxalic acid, and cryftal¬
lized.
16. Tartrate of Cobalt.
The oxide of cobalt is foluble in tartaric acid, and
forms a red coloured folution, which affords cryftals
by evaporation.
II. A&ion of Alkalies, Earths, and Salts.
1611
I. The alkalies have no action whatever on cobalt j Alkalies,
but w’hen the oxides are fufpended in water, they fe-
parate them from other matters. 1613
5. Some of the earths, but particularly filica, enters Earths,
into combination with the oxide of cobalt and the fix¬
ed alkalies, and forms a beautiful blue-coloured glafs.
The quantity of oxide muft be fmall, otherwife the
glafs will appear nearly black and opaque, on account
of the intenfity of the colour. 1^I-
3. Some of the neutral falts expofed to a high tempe- Salts,
rature along with cobalt burn with a perceptible dame.
It is by this means that the oxide is prepared for the
purpofe of enamels and colouring porcelain.
The hyperoxymuriate of potafti, with one-third of
its wreight of cobalt in pow’der detonates by percul-
fion.
4 K 2 Cobalt
628
Nickel,
&c.
u— .r—
1614
Ufes.
1615
Hiftory.
1616
©res.
CHEMISTRY.
Cobalt is fcarcely at all employed in the metallic
ftate. Zaffre is ufed for coarfe enamels and pottery
ware. The purer oxides of cobalt are chofen for the
purpofes of porcelain. A%ure is a vitreous blue in the
ftate of fine powder, which is prepared for fimilar pur¬
pofes. ZafFre is fufed along w'ith filica and an alkali,
and thus forms a deep blue glafs, which is known by
the name of /malt. This is reduced to a powder, and
mixed with a great quantity of water. The firft por¬
tion which precipitates is called coarfe a%ure. Four
different quantities are feparated in this way. The
laft, which is the fineft, is called azure of four
fires.
Sect. IX. Of Nickel and its Combinations.
The firft mention which is made of this metal is by
Hierne, a Swedilh chemift, in a work entitled Tihe art
of difeovering metals, \i\xh\\i\rLtd in 1694. He particu¬
larly deferibes the mineral from which nickel is extrac¬
ted, and which was firft called bupfernickel, or falfe
copper, becaufe it was taken for an ore of copper, and
none could be obtained from it. This was the opinion
of Henckel and Cramer, wTho fuppofed it to be copper
combined with arfenic or cobalt. This mineral was
generally arranged among copper ores, till it was ex¬
amined and analyzed by the celebrated Swedifh mine-
ralogift Cronftedt, in 1751, and 1754. In thefe ex¬
periments, the account of which was publifhed in the
memoirs of the Swedifti Academy, he proved that this
mineral contains a new metal, different from all thofe
which had been hitherto known, to w’hich he gave the
name of nickel. This opinion was generally adopted,
and objedted to only by Monnet and Sage of France,
who affirmed that this new metal was merely an alloy
of cobalt, arfenic, iron, and copper. To remove thefe
differences of opinion with regard to this fubftance,
Bergman undertook an elaborate analyfis of the ores of
nickel, and an accurate examination of its peculiar pro¬
perties in the metallic ftate. His experiments were
detailed in a differtation which was publiihed in 1775.
The objedf of his refearches was, to afeertain if nickel
was a peculiar metal ; and from the refult of his experi¬
ments it appeared, that it did not contain the fmalleft
trace of copper, but that it is generally alloyed with
cobalt, arfenic, and iron, from which indeed it can
fcarcely be completely feparated ; but that it poffeffed
peculiar and diftindl properties from the other metals;
and thefe properties became more ftriking and charac-
teriftic in proportion to its purity.
2. Nickel is found in the ftate of fulphuret, when it
is called kupfernickel. It is of a reddifh yellow co¬
lour, with little brilliancy, fomewhat fimilar to tar-
niftied copper, with which, from its appearance, it is
frequ«ntly confounded. This mineral foon lofes its
brilliancy in the air, becomes of a brownifti colour,
and is covered at laft with greenifti fpots. It is
found forming veins in the earth, and is ufually
combined with arfenic, cobalt, and iron. Nickel has
been found alloyed with iron, when it is of a laminat¬
ed texture, and compofed of rhomboidal plates. The
frefli frafture is of a pale yellow, which becomes black
by expofure to the air. Nickel is alfo found native in
the ftate of oxide, when it is of a bright green colour.
Nickel,
&c.
1617
In this ftate it is generally oil the furface of fulphuret
of nickel. Native nickel has alfo been found, accord¬
ing to Bergman, or at leaft with a very fmall propor¬
tion of fulphur, but combined with iron, cobalt, and
arfenic. He fays, too, that it exifts in combination
with fulphuric acid.
3. To obtain nickel from its ores in the ftate of ful-Separation
phuret, they are firft; roafted, by which means the ful-°* ft16 me-
phur and arfenic are driven off. In this procefs the mi-ta*'
neral lofes one-third or one-half of its weight; and in
proportion to the quantity of pure metal, which exifts
in the ore, it affumes a richer green. The roafted ore
is then mixed with two parts of black flux, put into a
crucible covered with muriate of foda, and expofed to
a forge heat, to bring it to fufion. When the appara¬
tus has cooled, there is found under the brown, black,
or blue fcoriae, a metallic button, which amounts to
one-tenth, and fometimes to one-half, of the mineral
employed. _ ... 1618
4. Nickel, in the pureft ftate in which it can be ob-Properties,
taiued, is of a yellowifli white, or of a reddifh white
colour, with more or lefs luftre, and of a granulated
texture. The fpecific gravity is 9 according to Berg¬
man, but according to Guyton it is only 7.807. Berg¬
man fpeaks of it as poffeffing fome degree of duflility j
but this, it is fuppofed, is owing to its alloy with iron,
which latter conftitutes -5- of its weight. It is alfo mag¬
netic, and this property has alfo been fuppofed to de¬
pend on the fame alloy. Nickel is a very infufible
metal, requiring a temperature equal to 150° Wedg¬
wood. Its power of conducing caloric has not been
afeertained, nor has its tafte or its fmell been recog¬
nized. It has never been obtained in cryftals. r(Jr^
5. When nickel is expofed to heat in an open veffel, Aflion of
it combines with oxygen, and affumes a brown colour jheat.
but this requires a very high temperature. After long
expofure to the air, when it is moift, and in the cold,
it becomes covered with an efflorefcence of a bright
green colour, of a peculiar and diftinft fhade. It is this Oxide,
efflorefcence which is found on the furface of the na¬
tive fulphurets of nickel, the fhade of which is fo re¬
markable, and fo different from that of copper, that
they can be eafily diftinguifhed. This oxide is com¬
pofed of
Nickel,
Oxygen,
77
23
100
6. There is no a&ion between nickel and azote,
hydrogen, or carbone 5 nor is it at all afted upon by
water. . . 1621
7. Nickel combines with phofphorus, and forms with Phofphu-
it a phofphuret. This is prepared by decompofing ret.
phofphoric acid in the ftate of glafs, which is done by
mixing phofphoric glafs, charcoal and nickel, and fufing
them together Or it may be prepared, by proje&ing
bits of phofphorus on the metal, while it is red-hot, in
a crucible. It acquires an addition of one-fifth part to
its weight j but it parts with a fmall portion of phof-
phox-us as it cools. The phofphuret of nickel is of a
more brilliant and purer white than the metal itfelf.
The texture refembles a colleftion of fmall needles
heaped together. When it is heated under the blowT-
pipe,
162 z
Compofi-
tion.
* Ann. de
Chim. xiii.
I35’
1623
Sulphuret.
1624
Alloys.
1625
Salts.
162,6
Affinities.
pipe, the phofphorus burns on its furface, and the me¬
tal is oxidated. The component parts of this phofphu-
ret, according to Pelletier, are
Nickel, 83.^
Phofphorus, 16.^
8. Nickel combines readily with fulphur, and forms
with it a fulphuret, which is fomewhat different in its
properties from the native fulphuret. It is hard, of a
yellowifh colour, and in fmall brilliant facets. When
it is ftrongly heated in the open air, it gives out lumi¬
nous fparks.
9. Nickel enters into combination with feveral of
the metals, and forms with them alloys; the proper¬
ties of which are but little known. With cobalt and
arfenic it forms native alloys. T he alloy wuth the lat¬
ter is of a reddifh colour, has no magnetic property,
is confiderably hard, and its fpecific gravity is lefs than
the mean fpecific gravity of the two metals.
10. Nickel enters into combination with the acids,
and forms with them falts, which are diftinguifhed by
peculiar properties.
11. The order of the affinities of nickel and its
oxide, as they have been afcertained by Bergman, is the
following :
CHEMISTRY.
without effervefcence. The folution has a blackifh
green colour, wdiich affords rhomboidal, deliquefcent (
cryftals, that are decompofed by heat, and leave, after
being flrongly calcined, and giving out oxygen gas,
a black oxide. When the nitrate of nickel is expofed
to a w’arm dry air, it is deprived of its water of cry-
ftallization, and even of its acid, fo that there remains
behind only an oxide of the metal.
629
Nickel,
&c.
Nickel.
Iron,
Cobalt,
Arfenic,
Copper,
Gold,
Tin,
Antimony,
Platina,
Bifmuth,
Lead,
Silver,
Zinc,
Sulphur,
Phofphorus.
Oxide of Nickel.
Oxalic acid,
Muriatic,
Sulphuric,
Tartaric,
Nitric,
Phofphoric,
Fluoric,
Saclaftic,
Succinic,
Citric,
Lactic,
Acetic,
Arfenic,
Boracic,
Pruffic,
Carbonic.
1627
Prepara¬
tion.
1628
Properties,
I. Salts of Nickel.
1. Sulphate of Nickel.
Concentrated fulphuric acid, with the affiftance of
heat, is decompofed by nickel. Sulphurous acid gas
is difengaged, and there remains behind a gray mafs
foluble in wrater, to which it communicates a beautiful
green colour. By evaporating this folution, cryftals of
a pale emerald green are obtained, which are fulphate
of nickel. The oxide of nickel is alfo readily diffolved
by fulphuric acid, from which alfo cryftals are obtained.
It cryftallizes in the form of fquare prifms, or in de¬
cahedrons, which are compofed of two four-fided pyra¬
mids, truncated at the fummits.
2. Nitrate of Nickel.
Nitric acid oxidates and difiolves nickel with the
afliftance of heat. The oxide is diflblved by this acid,
3. Nitrate of Ammonia and Nickel.
This triple fait is formed, by adding ammonia in ex¬
cels to the folution of nitrate of nickel. This fait is
of a green colour. It is obtained in cryftals by eva¬
poration. The folution does not become turbid by the
addition of alkalies, but the metal is precipitated by
hydrofulphurets *. * Ann. dt
4. Muriate of Nickel. 2Iyt
Muriatic acid diffolves nickel and its oxide flowly,
except with the afliftance of heat. I he folution is
of a green colour, and affords irregular cryftals. The
muriate of nickel is decompofed by heat, and by ex-
pofure to the air.
5. Fluate of Nickel.
Fluoric acid diflblves the oxide of nickel with diffi¬
culty, and affords cryftals of a bright green colour.
6. Borate of Nickel.
The compound of boracic acid and nickel can only
be formed by double affinity, by adding the borate of
foda, for inftance, to a folution of nickel in acids.
7. Phofphate of Nickel.
Phofphoric acid has not a very ftrong affinity for
the oxide of nickel. The folution which is formed
is fcarcely of a green colour, and does not afford
cryftals.
8. Carbonate of Nickel.
Liquid carbonic acid, expofed to the contafl of nic¬
kel, did not appear to Bergman, to combine with the
metal. But when nickel is precipitated from its folu-
tions by means of alkaline carbonates, the precipitate
acquires a greater weight than when the pure alkali is
employed} from which it is concluded, that part of the
carbonic acid has combined with the oxide.
9. Arfeniate of Nickel.
Arfenic acid forms with the oxide of nickel a green
faline mafs, which is obtained by precipitating the
oxide of nickel from its folution in acids, by means of
an alkaline arfeniate. The arfeniate of nickel is in
the form of powder, which is fcarcely foluble in wa¬
ter.
Tungftate of Nickel. T
Molybdate of Nickel. /
xo.
11.
12.
13-
Chromate of Nickel. I
Columbate of Nickel. J
14. Acetate of Nickel.
■unknown.
Acetic acid diffolves the oxide of nickel, and forms
a fait in rhomboidal cryftals, which are of a deep green
colour.
ij1. Oxalate
630 C H E M
Marne‘C* 15. Oxalate of Nickel.
With the affiftance of heat, oxalic acid afls upon
nickel, and a pale green powder precipitates. This
fait is fcarcely foluble in water. It may be formed
alfo, by precipitating nickel from its folutions in ful-
phuric, nitric, and muriatic acids, by means of oxa¬
lic acid.
16. Tartrate of Nickel.
This fait, and the combinations of the oxide of nic¬
kel with the other acids, are unknown.
II. Aftion of Alkalies.
1639
Fixed alka- The fixed alkalies diffblve the oxide of nickel, but
lies. jn fmall quantity. They affume a yellow colour;
Ammonia ^Ut t^I*S ox^e very ^uhle in ammonia j the folution
of which is of a deep-blue colour, and of a peculiar
fhade. When it is evaporated, it precipitates in the
form of a blackilh brown powder, which paffes from
a blue to green. Moft of the metals feparate the nic¬
kel from this folution.
III. Attion of the Earths.
1. Many of the earths, as filica and alumina, have
no aftion on nickel ; but others, as barytes and ftron-
tites, convert the oxide in folution into an orange red.
If it contain arfenic or cobalt, the glafs, which is co¬
loured with nickel, becomes of a blue or violet colour.
2. The nitrates and the hyperoxymuriates very
readily decompofe the falts of nickel, and reduce it to
the date of oxide. With the boracic and phofphoric
ialts it aflumes a pale red colour. The nitrate of pot-
a(h detonates feebly with nickel, but has the property
of detefling the fmalleft trace of cobalt, which could
not have been difcovered by any other reagent.
Ufes. So far as is known, this metal has not been applied
to much ufe. There is, however, little doubt, that it
might be employed for enamels, and for colouring
glafs, porcelain and pottery. Fourcroy obferves, that
it is probably employed in fome of the fecret procefles
of thefe manufa&ures, as it is brought from Saxony to
Paris in confiderable quantities.
Sect. X. Of Manganese and its Combinations.
1632
Hiftory. I. A fubftance was long employed in the manufac¬
ture of glafs, which, on account of its property of de¬
priving glafs of its colour, was known under the name
of glajfmaker's foap ; from its appearance it was called
b/ack magnefa, or manganefe. But although it was
long employed in manufa&ures, nothing was known
of its intimate nature or conftituent parts. It was ge¬
nerally confidered as an ore of iron, becaufe it was
found fometimes combined with the oxide of this me¬
tal. By others it was arranged among the ores of zinc
fuppofing that it was fome combination of this metal!
Fo Beigman and Scheele we are indebted for the
firft accurate knowledge of its nature. Bergman
in a differtation which he publifhed in 1774, an!
nounces it as a peculiar metal, on account of its
weight, its property of colouring glafs, and of afford¬
ing a white precipitate with the alkaline pruffiates.
Scheele, in the fame year, prefented to the academy of
Stockholm, a memoir, containing his refearches con-
I
I S T R Y.
cerning the nature and peculiar properties of this mi-Nanganefe,
neral. From thefe experiments he concludes, that ^c*
this mineral is the oxide of a peculiar metal, totally v
diftindl from all others. Gahn, the pupil of Berg¬
man, v’as the firft who obtained the metal in its pure
ftate, from the native oxide of manganefe. His ex¬
periments have been repeated by others, and the refults
of Scheele and of Bergman fully confirmed.
2. Manganefe is moft generally found in the ftate of Ore?/"
oxide. Of this there are three principal varieties, the
white, the-red, and the black. 1. The firft, or the
white ore of manganefe, contains the fmalleft proportion
of iron and of oxygen. Sometimes it is cryftallized.
This ore foon tarnifiies in the air by abforbing oxygen.
2. The red ore of manganefe contains more iron than
the former. It is either friable, or hard as it is found
in carbonate of lime, on ftnftus, or accompanying ores
of iron ; or in lamellated maffes, radiated or cryftal¬
lized in pyramids, rhomboids, or in Ihort brittle
needles. 3. The black or the brown ore is frequent¬
ly cryftallized like the red. It is alfo found in folid
maffes having a metallic or dull earthy appearance,
mixed with quartz and other ftony bodies. The fpeci-
fic gravity is 4.0. Manganefe has been found native by
Lapeyroufe in fome iron mines in France. It w'as in
the form of fmall, flattened, metallic buttons, of a
lamellated texture. But it has been fuppofed that
the manganefe in this ftate is alloyed with iron. 2634
3. Manganefe is procured in the metallic ftate bySeParatic?n
the following procefs. The native oxide of manga- ^jthe me*
nefe is reduced to a fine powder, and formed into a
pafte with water. Part of it is then made into a
ball, and introduced into a crucible lined with char¬
coal. A thick ftratum of charcoal is placed at the
bottom of the crucible, and the ball of manganefe is
to be furrounded and covered with the fame fubftance,
and the crucible, which is inverted and luted to the
other, is to be filled with it. The whole is then to be
expofed to a very ftrong heat, not lefs than 160°
Wedgwmod, for more than an hour. When the appa¬
ratus cools the metal is found in the bottom of the cru¬
cible, or in the midft of the fcorise, in the form of glo¬
bules, which amount to nearly one-third of the manga¬
nefe employed. But if the heat has been too low it
will be found in grains. 1635
4. Manganefe is of a grayifh white colour, with ProPerties*
confiderable brilliancy, and of a granular texture.
The fpecific gravity is 6.850. It has neither tafte nor
fine 11. In hardnefs it is equal to iron. It is one of
the moft brittle of the metals, and at the fame time
one of the moft infufible, requiring a temperature of
1600 Wedgwood to melt it. When in the (late of
powder it is often attra&ed by the magnet, on account
of the iron, from which it can only be feparated with
great difficulty. _ ' _ ^
5. When this metal is expofed to the air, it is foon Adlionof
tarnifhed. It becomes gray, brown, and black, andair*
at laft falls down into powder, which is found to have
acquired conuderable addition to its ■weight. But
when it is heated in the open air, it paffes more rapid¬
ly through the different changes of colour, in propor¬
tion as it combines with oxygen, to the abforption of
which thefe changes are owing. It appears, therefore
that manganefe, like fome of the other metals, com¬
bines with different portions of oxygen, forming differ¬
ent
C H E M I
Mariganefe, ent oxides. The black oxide, which is manganefe, com-
, £lc- , bined with oxygen in the greateft proportion, is found
native in great abundance. The red oxide is fuppofed
to contain the oxygen in the next proportion. This
alio exifts native, and it may be formed by diftilling
the black oxide made into a pafte with concentrated
fulphuric acid in a retort to drynefs. It is deprived
of a great quantity of oxygen, which is given out in
the date of gas. The refiduum is then to be mixed
with water, which is to be filtered. This folution,
which is fulphate of manganefe, is of a red colour.
By adding an alkali a precipitate is formed, which is
the red oxide_of manganefe. The white oxide is alfo
prepared by depriving the black oxide of part of its
oxygen. This is eflfe61ed by pouring nitric acid on
the black oxide of manganefe, with the addition of
fugar, which abforbs the oxygen and converts it into
the white oxide. The latter is then diffolved in the
acid, from which it may be precipitated by potafh.
The precipitate is in the form of a white powder.
The proportions of manganefe and oxygen in the
white and brown oxides of manganefe, according to
Bergman, and in the black, according to Fourcroy,
are,
16.37
Oxides.
1638
Black.
1639
Red.
1640
White.
White Oxide.
Manganefe 80
Oxygen 20
Brown Oxide.
74
26
Black Oxide-
bo
40
IOO
IOO
100
1641
Furniihes
oxygen.
1642
Phofphu-
ret.
When thefe oxides are expofed to the air, they abforb
oxygen, and are again converted into the black ox¬
ide with the greater proportion of oxygen.
It is from the black oxide of manganefe that che-
mifts generally procure oxygen gas. The moll econo¬
mical procefs is that w’hich has been already defcribed
in the chapter on oxygen. This is by expofing it to
a red heat in an iron bottle. The manganefe is redu¬
ced to the ftate of red oxide by being deprived of the
difference of the quantity of oxygen between the black
and the browm oxides. The fame manganefe may be
employed after it has been for fome time expofed to
the air, and occafionally moiftened with water. This
procefs, however, goes on much more dowdy than is
generally fuppofed. We have kept feveral quantities of
manganefe, wdiich had furnifhed abundance of oxygen,
and had ceafed to give out more in a red heat, expofed
to the air for many months, and frequently moiftened
with water, but w'hen it wTas again heated to rednefs,
it did not yield above part of the original quantity
from the native manganefe.
7. Manganefe does not enter into combination with
azote, hydrogen, or carbone. It is by means of
charcoal that the oxide of manganefe is reduced, by
being deprived of its oxygen 5 and what has been fup-
-pofed to be a compound of manganefe and carbone,
is a carburet of iron, or carbone combined with the
iron, with which manganefe is almoft always al¬
loyed.
8. Phofphorus combines very readily with manga¬
nefe. Pelletier formed the phofphuret of manganefe by
fufing a mixture of equal parts of manganefe, in the
metallic ftate and phofphoric glafs, with about -g. part of
charcoal in powTder j or by fufing equal parts of the two
former without the charcoal j or by projecting fmall bits
S T R Y. , . . ^
of phofphorus on manganefe heated to fednefs in a Manganefe,
crucible. The phofphuret obtained by any of thefe pro- ,
ceffes, is of a white colour, of a granulated texture and
brittle, and much difpofed to cryftallize. It under¬
goes no change by expofure to the air. It was co¬
vered with an opake, vitreous matter of a yellowifti co- ^ ^ ^ ^
lour. It is more fufible than the manganefe itfelf. Chi>r.. xiih
When it is expofed to the aClion of the blow'-pipe, the 137.
phofphorus burns, and the metal is oxidated *. 1643
9. Bergman failed in forming a compound with fuI_Sulphured
phur and manganefe by direft combination. But he
fucceeded in combining fulphur with oxide of manganefe.
Three parts of fulphur, and eight parts of the oxide,
expofed to heat in a glafs retort, formed a greenilh
yellow mafs, wTich effervefced with acids, and emitted
fulphurated hydrogen gas. Scheele has obfisrved, that
a part of the fulphur is converted into fulphurous
acid during the procefs.
10. Manganefe enters into combination with the 1544
acids, and forms falts with them. The order of the Affinities,
affinities of the oxides of manganefe for the acids, ac¬
cording to Bergman, is the following :
Oxide of Manganese.
Oxalic acid.
Citric,
Phofphoric,
Fluoric,
Muriatic,
Sulphuric,
Nitric,
Saclaftic,
Succinic,
Tartaric,
Ladlic,
Acetic,
Pruffic.
Carbonic.
I. Salts of Manganefe.
1. Sulphate of Manganefe.
r. Concentrated fulphuric acid adls on manganefe,
even in the cold ; but the adlion is more powerful if
the acid be diluted with two or three parts of water.
Hydrogen gas is given out, and there remains behind
in the liquid, a black, fpongy mafs, which is the car¬
buret of iron. The folution is colourlefs, and it affords
by evaporation, tranfparent, colourlefs cryftals. Sul¬
phuric acid does not combine with the black oxide of
manganefe, till it is deprived of part of its oxygen, and
reduced to the ftate of red or white oxide ; but the
acid combines with either of the two latter oxides, 1C45
forming falts poffeffed of diftindt properties. There Two fut-
are, therefore, two fulphates of manganefe, which mayphates.
be diftinguiftied, from the colour of the bafe or oxide,
by the names of white and red fulphates. I(^
White fulphate of manganefe.—This is the compound With the
of fulphuric acid and the white oxide of manganefe. white ox-
This oxide combines with the acid without effervefeence, ^e*
and forms a colourlefs folution, which yields by evapo¬
ration, tranfparent rhomboidal cryftals, which have a
Very bitter tafte. This fait is decompofed by heat j
the acid is driven off, and oxygen gas is given out. It
is decompofed alfo by the pure alkalies, and a precipi¬
tate
632 C H E M I
JManganefe, tate 5s formed, of tire white oxide of manganefe, which
&cc- foon becomes brorvn by expofure to the air, in confe-
v~" ’ quence of the abforption of its oxygen. The alkaline
carbonates precipitate a carbonate of manganefe, which
does not abforb the oxygen from the air, and does not
become black like the former. It is the white lul-
phate of manganefe, which is obtained by diffolving
the metal in diluted fulphuric acid. In this procefs
the manganefe combines with the oxygen ol the water,
which is decompofed, and is converted into the white
oxide, which unites with the fulphuric acid, to form
the fulphate. The hydrogen of the water is driven
off in the Hate of gas, fo that the fait formed in this
way, occafions an effervefcence. T his fait may alfo
be formed by diffolving the black oxide in fulphuric
acid ; but in this cafe it is neceffary, as Scheele dif-
covered, to add fome vegetable matter, as fugar,
honey, or gum, to abforb the fuperabundant quantity
of oxygen, which prevents the folution of the manga¬
nefe in the acid. When, therefore, the black oxide is
reduced to the ftate of white oxide, by depriving it of
part of its oxygen, it combines with the acid, and
forms white fulphate of manganefe, as in the former
1647 proceffes.
With the Red Sulphate of Manganefe.—If the black oxide of
red oxide, manganefe be diflilled to drynefs tvith fulphuric acid,
diluted with half its weight of water, and if the refi-
duum be wafhed with water, a reddilh or violet-co¬
loured folution, which is the red fulphate of manga¬
nefe, is obtained. By evaporation it affords thin cry-
ftalline maffes, which have no regular form. Thefe
are alfo of a reddifh colour. The alkalies occafion a
red precipitate, which becomes black by expofure to
the air. This fulphate may be alfo formed by the di-
re£I combination of the red oxide with the acid.
Bergman has obferved, that the red oxide of man¬
ganefe is intermediate between the black and the
white ; that it is more foluble in fulphuric acid than
the former, and lefs foluble than the latter 5 that the
red forms a red-coloured fulphate, while the white
affords a colourlefs fulphate.
Sulphurous acid a£ts feebly or fcarcely at all on
manganefe ; but it diffolves the black oxide readily,
and without effervefcence. There is not formed, how¬
ever, a fulphite of manganefe j for the fulphurous acid
deprives the black oxide of a portion of its oxygen,
and thus converts it into a white oxide, while the acid
itfelf is converted into fulphuric acid. The white
oxide is then diffolved in the fulphuric acid, and forms
the white iulphate of manganefe.
8 2. Nitrate of Manganefe.
White ox- Nitric acid diffolves manganefe with effervefcence,
hie. and with the evolution of nitrous gas. There remains
behind a black, fpongy mafs, which is carburet of
iron, and infoluble. The folution thus formed, is of
a dark colour, on account of the iron which it con¬
tains 5 for it does not appear that the red oxide of
manganefe combines with nitric acid. The white ox¬
ide of manganefe diffolves very readily in nitric acid,
and without effervefcence, or the emiffion of nitrous
gas. This folution, if the oxide be pure, is colour¬
lefs. It does not afford cryftals, even by flow evapo¬
ration. The black oxide of manganefe cannot be dif¬
folved ip nitric acid, but by long digeflion j but by
1
S T R Y.
adding fome vegetable matters, as honey, fugar, oils, Manganefe
or even fome of the metals, to deprive the oxide of part &c-
of its oxygen, the combination is effe&ed. Carbonic
acid gas, which is formed by the union of the car-
bone of the vegetable matters with the oxygen of the
manganefe, is given out, during the procefs.
2. Nitrous acid diffolves the oxide of manganefe
much more readily than the nitric acid. No effervef¬
cence takes place, becaufe the oxygen of the manga¬
nefe combines with the nitrous acid, and forms nitric
acid, wdiich latter combines with the oxide of man¬
ganefe, reduced to the ftate of white oxide ; and
thus there is formed, not a nitrite, but a nitrate of
manganefe.
3. Muriate of Manganefe.
i&p)
Manganefe is diffolved wuth effervefcence, and with White ox-
the evolution of hydrogen gas, in liquid muriatic acid.ide.
The white oxide combines with the acid, without ef¬
fervefcence, and without the feparation of any gas,
becaufe it is fufficiently oxidated, to be diffolved in
this acid. The black oxide is diffolved with equal fa¬
cility in muriatic acid as in the othef acids. In this
cafe an effervefcence takes place, wdth the difengage-
ment of oxymuriatic acid gas. The nature of this ac¬
tion is obvious. Part of the muriatic acid combines
wdth part of the oxygen of the manganefe, and forms
oxymuriatic acid, wdiich is difengaged in the ftate of
gas. The black oxide is deprived of part of its oxy¬
gen, and converted into the white oxide, wdrich lat¬
ter difl'olves in the remaining part of the muriatic acid,
and forms a muriate of manganefe. This fait, being
a compound of the wTite oxide of manganefe and mu¬
riatic acid, may be called the white muriate of manga¬
nefe. If any combuftible matter be added, the folu¬
tion of the black oxide of manganefe in this acid goes
on, without the produftion of oxymuriatic acid.
Oxymuriatic acid readily parts with its oxygen to
manganefe, which is thus converted into the white ox¬
ide. It combines alfo with the oxides of manganefe,
and forms folutions of a brown, red, or violet colour,
which afford cryftals of the fame colour. 1 here is,
therefore, a red muriate of manganefe.
It is from the black oxide of manganefe, that oxy¬
muriatic acid is obtained, either by adding to the
oxide muriatic acid, part of which combines with the
oxygen of the manganefe, and is converted into oxy¬
muriatic acid 5 or, by adding fulphuric acid to a mix¬
ture of the black oxide of manganefe and muriate of
foda. The fulphuric acid decompofes the latter, and
the muriatic acid being difengaged, combines with
part of the oxygen of the manganefe, and forms oxy¬
muriatic acid.
4. Fluate of Manganefe.
Fluoric acid has little action on manganefe or its
oxides j but a fiuate of manganefe may be formed by
double affinity, by adding an alkaline fluate to the
nitrate or muriate of manganefe. The fluate of man¬
ganefe thus formed, is not very foluble in water. Its
other properties are unknowm.
5. Borate of Manganefe.
This fait may be formed in the fame way as the
former.
CHEMISTRY.
Manganefe,former. It is equally folubie in water, and its other
, ^c’ properties are alfo unknown.
6. Phofphate of Manganefe.
A phofphate of manganefe may be formed in the
fame way as the two former falts. It is not very fo¬
lubie in water, and its other properties have not been
examined.
7. Carbonate of Manganefe.
Liquid carbonic acid diffolves a fmall portion of
manganefe, as well as of its black oxide. When this
folution is expofed to the air, the oxide is gradually
precipitated, and appears on the furface in the form
of a white pellicle. Bergman has remarked, that dur¬
ing the combination of manganefe with carbonic acid,
there is evolved an odour fomewhat analogous to that
of burnt fat.
8. Arfeniate of Manganefe.
Arfenic acid combines with the white oxide of man¬
ganefe, and forms an arfeniate. The arfenious acid,
or white oxide of arfenic, deprives the black oxide of
manganefe of part of its oxygen, and pafles to the Hate
of arfenic acid, and then combines with the manga¬
nefe, now reduced to the date of white oxide. When
the arfenic acid is nearly faturated with the oxide,
the folirtion becomes thick, and fmall cryftals make
their appearance. This fait, when heated, does not
melt, nor is the arfenic fublimed, without the addi¬
tion of charcoal.
6sz
9. Tungdate of Manganefe.
10. Molybdate of Manganefe.
11. Chromate of Manganefe.
1 2. Columbate of Manganefe.
unknown.
1650
Procefs for
feparating
* Ann. de
Cbim. xli.
P- 24P*
13. Acetate of Manganefe.
Acetic acid diflblves part of the black oxide of man¬
ganefe, but a£ts very feebly on the metal itfelf. This
acid may be employed to feparate manganefe from
iron ; for when it is added to a folution containing
both thefe metals, the acid combines with the manga¬
nefe, for which it has a dronger adinity, and leaves
the oxide of iron. Several fuccedive folutions and
evaporations are neceflary to feparate the whole of the
iron, which is known when the folution becomes co-
lourlefs, and when it affords a w’hite precipitate wdth
prudiate of potadi. The folution of acetate of man¬
ganefe does not crydallize, and when evaporated to
drynefs, it foon deliquefces *.
14. Oxalate of Manganefe.
Oxalic acid forms a fait with the oxide of manga¬
nefe, which, w’hen the folution is faturated, precipitates
in the form of white powder. It may be formed alfo
by adding oxalic acid to the fulphate, nitrate, and mu¬
riate of manganefe in folution.
15. Tartrate of Manganefe.
This fait may be formed by double affinity, by add¬
ing tartrate of potadi to the folution of manganefe in
fulphuric or nitric acids. The black oxide of manga¬
nefe is diffolved in tartaric acid, and gives a black-co¬
loured folution. When it is heated, an effervefcence
Vox. V. Part II.
takes place ; the acid is partially decompofed, car- Mangaoefe*
bonic acid gas is evolved, and the folution at lad;, &'c- ^
becomes colourlefs. v J
16. Citrate of Manganefe.
Citric acid, in its combination with the black oxide
of manganefe, exhibits the fame phenomena as the
former.
17. Benzoate of Manganefe.
Benzoic acid readily combines with the white
oxide of manganefe. By evaporation, cryftals in the
form of fmall fcales are obtained, which are little al¬
tered by expofure to the air, and are folubie in water.
II. A£lion of Alkalies on Manganefe.
1. The pure alkalies favour the oxidation of man-pUre alka-^
ganefe, and the decompofition of water, becaufe they lies,
combine readily with this oxide. In the dry way,
the fixed alkalies fufe with manganefe, and form a
mafs of a deep green colour, which is folubie in w'a-
ter, and communicates to it the fame colour. If
this folution be kept in a clofe veffel, there is preci¬
pitated an oxide of iron, of a yellowifh colour, and
the green liquid changes to a blue. Water precipi¬
tates the alkaline folution, and converts it, firft to a
violet and then to a red colour. As the particles of
the oxide colleft together, the liquid becomes white.
The addition of a few drops of acid, on expofure to
the air, produces the fame precipitation, and the fame
{hades of colour, by oxidating the manganefe. The
white oxide of arfenic, or arfenious acid, added to this
alkaline folution, deprives it of the whole of its colour,
and renders it white, by combining with the oxygen.
By adding charcoal to the oxide of manganefe which
has been fufed with an alkali, an effervefcence takes
place, with the evolution of carbonic acid, and the
colour of the folution changes to a grayilh white.
The carbonic acid is here formed by the union of the
carbone of the charcoal wuth the oxygen of the man¬
ganefe, and this latter paffes to the ftate of white
oxide. On account of thefe remarkable changes of
colour, and the different {hades which this liquid, treat- Mineral
ed in various ways, affumes, this compound has re-camelcoa.
ceived the name of mineral came/eon.
2. Scheele had obferved the change which ammonia Ammonia.-
undergoes by the adlion of oxide of manganefe, in the
diftillation of this oxide with the muriate of ammonia.
He fufpedled that the ammonia was partially decom¬
pofed, and to this decompofition he afcribed the for¬
mation of a gas, which he obtained by this procefs, and
wffiich he found to be different from carbonic acid.
Berthollet has {hewn, that in this procefs, the hydro¬
gen, leaving the ammonia which is decompofed, com¬
bines with the oxygen of the oxide of manganefe,
and forms water 5 and the azote, the other compo¬
nent part of ammonia, is fet at liberty.
A very interefting experiment was contrived by Curious ex-
Dr Milner, which illuftrates the reciprocal action, anciperiment.
decompofitions of the oxide of manganefe and ammo¬
nia. He filled a tube with oxide of manganefe,
expofed it to a red heat, and made a ftream of ammo-
niacal gas pafs through it. The gas was decompofed*
and its azote combining with the oxygen of the oxide,
forme^ nitrous gas.
4
Some
634
Bifmurh,
&c.
Colours
glafs.
f6i6
Ufes.
. l657
Hiftory.
1658
Ores.
1659
Analyfis
in the dry
way.
C H E M I
Some of the alkaline falts have peculiar effe&s on
the oxides of manganefe and their compounds. The
fulphates have the property of deflroying the colour of
glafs, which has been communicated by manganefe ;
but for this effett a high temperature is neceffary. The
nitrates readily burn this metal, and oxidate it ftrong-
ly. Melted nitre gives a violet or red colour to glafs,
which has been rendered colourlefs, in reftoring to it
the oxygen of which it has been deprived by the fufion
of the"^ glafs. With the nitrate of potafli and the
black oxide of manganefe, heated in a crucible to red-
nefs, a compound is formed, fimilar to that which is
the refult of the direft combination of the oxide with
the alkali.
The alkaline phofphates and borates fufed by means
of the blow-pipe, with the oxide of manganefe, produce
various colours, according to the degree of oxidation,
and the intenfity of the heat.
A white precipitate is formed, by adding hydroful-
phuret of potalh to the falts of manganefe, and a yel-
lowifh-white precipitate is obtained, by means of the
triple pruffiate of potafh.
III. A&ion of the Earths on Manganefe.
There is no a£Hon between manganefe and any of
the earths j but its oxide combines with them, and forms
vitreous matters, which are of different colours, accord¬
ing to the degree of oxidation of the manganefe, and its
mixture with iron. In general thefe colours are green,
brown, black, or yellowilh green.
Manganefe and its oxides are of great importance,
both in chemiftry and in the arts. This muft be ob¬
vious, from the minute detail of its properties and com¬
binations, which has now been given.
Sect. XI. Of Bfsmuth and its Combinations.
1. Bifmuth, it would appear, was known to the an¬
cients, to the alchemifts, and fome of the earlieft mine-
ralogifts but it was confidered merely as a variety of
fome other metal, and generally of tin and lead. Hence
it was diftinguifhed by the name of green tin, gray lead,
and white antimony. It was not till the year 1793,
when its properties were particularly examined by Pott
and Geoffroy the younger, that it was afeertained to be
a peculiar metal. Darcet and Rouelle afterwards in-
ftituted a fet of experiments on this metal, and difeo-
vered more of its properties. Monnet and Beaume in-
veftigated its principal combinations at Hill greater
length; and Bergman examined with more accuracy,
fome of its compounds and precipitates.
2. Bifmuth is found native in the ftate of fulphuret,
and in that of oxide. Native bifmuth is eafily diftin-
guithed by its colour, brittlenefs and fufibility. The
fulphuret of bifmuth is of a bluifh gray, fometimes with
a yellowifh fhade, and is in irregular maffes, or cryftal-
lized in the form of fmall prifms. It has a brilliant,
lamellated fra&ure. The native oxide of bifmuth ac¬
companies the metal, or is found on the furface of the
fulphuret. It is of a greenifh yellow colour.
3. Bifmuth is eafily extrafted from its ores. The
mineral, after being reduced to powder, and well wafhed
is mixed with about % of its weight of black flux, is put
into a crucible lined with charcoal, and well covered.
♦
S T R- Y.
It is then expofed to a moderate heat, which muft be Bifmutft,
quickly applied, to prevent the metal from being fub- &cc- f
limed. By this procefs a metallic button is obtained. * v
In the humid way, the ore of bifmuth being redu- Hu^^°
ced to powder, is diffolved in nitric acid, and precipi-way*“
tated from this folution by water. If the native bif¬
muth be combined with any other metals, they remain
in the folution. The fulphuret of bilmuth is alfo dif¬
folved in the fame acid by boiling. The fulphur is fe-
parated, as the metal, being oxidated, combines with
the acid. The native oxide is treated in the fame way,
and is precipitated by water. j66r
4. Bifmuth is of a white colour, inclining to yellow, Properties*
exhibiting a texture compofed of large brilliant plates.
Its fpecific gravity is 9.822. It has fcarcely either tafte
or fmell. By a violent ftroke of the hammer it is bro¬
ken, and divides into fmall fragments of a lamellated
ItruAure ; the figure of its particles is the regular
odlahedron. It has confiderable hardnefs; and by ham¬
mering, its denfity may be increafed. It has very lit¬
tle elaflicity, and no duftility. Bifmuth is very fufi-
ble. When it is expofed to the temperature of 490°,
according to Guyton, it melts ; and, if after fufion, it be
allowed to cool fiowly, it cryftallizes in parallelepipeds,
which crofs each other at right angles. This metal
cryftallizes more eafily and more regularly than any
other yet known. If the heat be long continued after
the fufion, and fufticiently ftrong ; and if the procefs be
conduced in clofe veffels, it fublimes, and attaches it-
felf to the upper part of the apparatus, where it cryftal¬
lizes in brilliant plates.
5. Bifmuth is but flightly affefted by expofure to
the air in the cold. It lofes its brilliancy, and is co¬
vered with a fine powder of a yellowilh gray colour;
but, when it is heated in contact with air, the furface
is foon covered with an iridefeent pellicle, which, by
agitation and continuing the heat, is converted into a
greenilh gray or browm-coloured oxide. It acquires
about -rV of addition to its weight. By continuing
the heat, and occafionally ftirring the fufed metal, it
becomes of an orange-yellow colour, and acquires a *
farther addition to its weight. If the metal in fufion
be expofed to a red heat, it takes fire with a flight ex-
plofion, burns with a bluifh flame, and is fublimed in
the form of a yellowifh vapour, which, being condenfed
and collected, is known under the name of flowers i66z
of bifmuth. It appears then, that bifmuth combinesTw0
with oxygen in two proportions. The firft, or the ant|
fmaller proportion, is that of the brown oxide; andyeiiow.
the fecond is the yellow oxide or flowers of bifmuth. l6(5^
6. There is no affion between bifmuth and azote, phofphurek
hydrogen, or carbone. It combines but in very fmall
proportion wuth phofphorus, forming a phofphuret.
When phofphorus is dropped into bifmuth in fufion, it
feems to unite wuth it, according to Pelletier, in the pro¬
portion of four parts in the hundred. But the proper¬
ties of the bifmuth are very little changed.
7. Sulphur unites readily with bifmuth. When equal Sulphuret
parts of bifmuth and fulphur are heated together in a
crucible, the fufion of the metal is greatly retarded.
It requires a higher temperature than w'hen the metal
is alone. This fulphuret of bifmuth is of a fhining
dark gray colour, and cryftallizes by proper cooling
into needle-form prifms, fhaded with iplendid blue and
deep
TRY.
Bifiruith,
See.
1665
Alloys and
falls.
1666
Affinities.
C H E M
deep red colours. The cryftals are obtained by pier¬
cing the furface when it becomes folid after fufion, and
pouring out the liquid parts : a cavity is thus left in
which they are formed.
Sulphurated hydrogen gas occafions a dark colour
on the furface of bifmuth, and converts the oxides into a
deep black colour, which is the commencement of re-
du£Hon.
8. Bifmuth combines with many of the metals, and
forms alloys ; but its combinations with the metals al¬
ready deferibed, are little or fcarcely at all known.
Bilmuth alfo combines with the acids, and forms falts.
9. The affinities of bifmuth and its oxides are arranged
by Bergman in the following order :
Bismuth.
Lead,
Silver,
Gold,
Mercury,
Antimony,
Tin,
Copper,
Platina,
Nickel,
Iron,
Sulphur.
Oxide of Bismuth.
Oxalic acid,
Arfenic,
Tartaric,
Phofphoric,
Sulphuric,
Muriatic,
Nitric,
Fluoric,
Sacla6Hc,
Succinic,
Citric,
Laftic,
Acetic,
Pruffic,
Carbonic.
I. Salts of Bifmuth.
The folutions of bifmuth in the acids, and alfo the
from other cryftallized falts which are obtained from them, re-
metallic lb- femble each other, but differ from almoft all other me-
iutions. tallic folutions, as well as from all other falts $ and
particularly in one circumftance, which is, that water
in fufficient quantity decompofes them, and precipitates
an oxide of bifmuth of a wffiite colour. This Ihows
that bifmuth is ftrongly oxidated by the a&ion of the
acids, to which it adheres with no great affinity, and
that it forms with them compounds which are not
very permanent. It feems at the fame time remarkable,
that this metal (hould be more oxidated in this w^ay,
than by the ufual procefs of oxidation, by means of
heat, and by the aflion of water •, and that it Ihould
have a white colour, wffiile in the ufual way, it is of a
yellowifh gray.
1. Sulphate of Bifmuth.
Concentrated fulphuric acid has no aftion on bif¬
muth in the cold ; but this metal decompofes the acid
at a boiling temperature. Sulphurous acid gps is dif-
engaged, and the bifmuth is oxidated, and converted
into a white powder. If the heat be ftrong, fulphur
is fublimed. When the remaining mafs is wafhed with
water, it carries off the remaining acid and a fmall
quantity of the oxide of bifmuth. The folution, by
proper evaporation, affords fmall foft needle-formed
cryftals, which are fulphate of bifmuth. This fulphate
is decompofed by water, which feparates a white
oxide.
P
1S67
Different
I s
2. Sulphite of Bifmuth.
63J
'Bifmuth,
See.
Sulphurous acid has no adlion on bifmuth; but it
unites with its oxide, and forms a white fulphite which
is infoluble in water, and even in its own acid 5 of a
fulphureous tafte j fufible by the blow-pipe into a red-
dilh yellow mafs, which is reduced on charcoal into
metallic globules ; decompofed wdth effervefcqpce by
means of fulphuric acid j giving out by diftillation
fulphurous acid, and leaving behind a pure white oxide.
q. Nitrate of Bifmuth.
r55S
1. Nitric acid exhibits a very violent aflion with Violent
bifmuth. When the acid is a little concentrated, anda^on*
the bifmuth in the ftate of powder, there is a violent
effervefcence, with the evolution of nitrqus gas. •There
is at the fame time great heat produced. The bifmuth
is converted into white oxide at the expence of the
acid, and when the a&ion ceafes, if no more acid be
added than what is neceffary to its oxidation, remains
dry. 1669
2. The nitric folution thus prepared, is colourlefs, ProPertleS*
and affords cryftals by evaporation. It cryftallizes in
tetrahedral prifms, compreffed into obtufe three fided
fummits. It has fometimes been obtained in flattened
rhomboidal parallelepipeds, fimilar to thofe of Iceland
cryftal. When this fait is thrown on red-hot coals,
it melts, boils, and froths up ; exhales nitrous vapour,
and leaves behind a greeniffi yellow oxide. It dries in
the air, and becomes moift when the air is humid.
When it is brought into conta6l with water, it becomes
turbid, is decompofed, and a white oxide is precipitat¬
ed. This decompofition is effefted with the nitric
acid, which is poured gradually into a large quantity
of water. The oxide which is thus obtained, v.-as for¬
merly called magijlery of bifmuth. It is known in
the fttops by the name of pearl white. It becomes of
a deep gray, brown, or even black colour, when it is
expofed to the adlion of fulphurated hydrogen gas.
4. Muriate of Bifmuth.
1670
Muriatic acid has but a feeble aflion on bifmuth. Prepara-
It is neceffary to affift its aflion, that the acid be con-tlon’
centrated, and long digefted with the metal, or diftil-
led off it in the ftate of powder. During the procefs,
a fetid odour is emitted, which is owing to the decom¬
pofition of water, its oxygen combining with the metal,
and the hydrogen being fet at liberty. By evaporat¬
ing this folution, fmall needles of muriate of bifmuth
are obtained ; but only in very fmall quantity ; for the
greateft part of the oxide of bifmuth is feparated by
water. The muriate is fublimed by heat, into a thick,
folid, fufible matter, which was formerly called butter
of bifmuth. It is deliquefeent, and may be decompofed
by water, which feparates a very fine white oxide.
O.xymuriatic acid readily diflblves bifmuth, and
forms with the oxide which is previoufly produced, a
fait fimilar to the preceding.
5. Fluate of Bifmuth.
6. Borate of Bifmuth.
Thefe two falts may be formed by adding a fluate
or borate of an alkali to a folution of nitrate of bif¬
muth. A white precipitate is formed of the fluate or
4 L 2 borate
636 C H E M I
jiifmuth, borate of bifmuth 5 but little is known of their pro-
, perties.
7. Phofphate of Bifmuth.
This fait is formed by combining the acid with the
oxide of the metal, when precipitated by an alkali.
The phofphate of bifmuth is in the date of an infoluble
white powder.
8. Carbonate of Bifmuth.
I
This fait may be formed by precipitating the «xide
of bifmuth from its folution in acids, by means of an
alkaline carbonate.
9. Arfeniate of Bifmuth.
Arfenic acid a&s upon bifmuth with the affiflance
of heat. A white powder appears on the furface of
the metal, and the oxide is precipitated from the fo¬
lution, by adding water. The arfeniate of bifmuth
may be formed, by adding arfenic acid to a folu¬
tion of the nitrate of bifmuth. The arfeniate of bif-
muth falls to the bottom in the form of precipitate.
to. Tungftate of Bifmuth.
Unknown.
11. Molybdate of Bifmuth.
Muriate of bifmuth is precipitated, if there be no
excefs of acid, by molybdic acid. The molybdate
of bifmuth thus formed, is of a white colour.
12. Chromate of Bifmuth, 1 ,
13. Columbate of Bifmuth, J un ncmn'
14. Acetate of Bifmuth.
This fait may be formed, by adding a folution of
acetate of potalh to a folution of nitrate of bifmuth.
A precipitate of acetate of bifmuth is formed. The
addition of acetic acid to the nitrate of bifmuth, Guy¬
ton obferves, prevented the latter from being precipi¬
tated by means of water.
15. Oxalate of Bifmuth.
Oxalic acid combines with the oxide of bifmuth,
and forms with it a fait in the ftate of wdiite powder,
which k fcarcely foluble in water. Oxalic acid added
to nitrate of bifmuth, occafions a precipitate in the
form of fmall tranfparent cryftals, which are oxalate
of bifmuth.
16. Tartrate of Bifmuth.
Tartaric acid added to the folution of bifmuth in
any of the mineral acids, precipitates the oxide in the
form of a white powder, which is the tartrate of bif-
snuth, and is infoluble in water.
17. Benzoate of Bifmuth.
Benzoic acid combines readily, with the oxide of
bifmuth. The folution, by evaporation, affords cry¬
ftals in the form of needles. They undergo no change
by expofure to the air, are foluble in water, and de-
compofed by fulphuric and muriatic acids. 7Tis fait
, is alfo decompofed by heat,, which drives off its
acid.
s T R Y.
18. Succinate of Bifmuth. Antimony,
• • • &LQ*
Succinic acid combines with the oxide of bifmuth, ^ - -t ‘ '
at a boiling heat. By evaporating the folution, cry¬
ftals of fuccinate of bifmuth are obtained, in the form
of plates, and of a yellow colour.
II. Aftion of Alkalies, Earths, and Salts, on Bif¬
muth.
1671
Scarcely any thing is known of the action of the Alkalies,
alkalies on bifmuth. Ammonia, it is faid, commu¬
nicates to it a yellow colour, and the oxide of bifmuth
is foluble in ammonia in the liquid ftate.
The oxide of bifmuth combines by fufion, with ft-Silica,
lica, to which it communicates a greenilh yellow co¬
lour. *673
Bifmuth is not changed by the adtion of the ful-Salts.
phates or fulphites. It is oxidated by the nitrates.
When it is ftrongly heated, and thrown into a red-hot
crucible with nitrate of potafh, it detonates feebly,
and without much inflammation. It is reduced to the
ftate of oxide, of which one part combines with the
potalh. Bilinuth has no aftion on muriate of ammo¬
nia, but its oxide very readily decompofes this fait.
In the cold, it difengages a little ammonia, by fim-
ple trituration ; but when expofed to heat, it is total¬
ly decompofed, and there remains a muriate of bif¬
muth.
Bifmuth is applied to a great many ufes. It forms ufes.
fome important alloys with the fofter metals, to give
them hardnefs and conliftency. The oxides of bif¬
muth are of ftill more extenfive utility. It is employ¬
ed in this form by the manufadlurers of porcelain, for1
the preparation of yellow enamels, and it is mixed
with other oxides, to give variety of lhade to their co¬
lours. It is fometimes employed in the fabrication of
coloured glaffes, to communicate a greenilh yellow.
The white oxide, which is moll commonly employed
for thefe different purpofes, is alio employed as a paint
for the Ikin, under the name pearl white; but it is
extremely improper for this purpofe, for, belides the
injury which it does to the Ikin, it becomes black,
when it is expofed to the aftion of fulphurated hydro¬
gen gas. It is fometimes ufed alio, to give a black
colour to the hair.
1674
Sect. XII. Of ylNtimony and its Combinations.
j. It does not appear that the ancients were ac-
quainted with antimony as a diftindt metal, although
it is fuppofed that it wras employed by them in alloys-
of other metals. It is faid, that they were acquainted
with the oxide of antimony, and that it was employed
as an external remedy in inflammation of the eyes.
As a peculiar metal, it was not certainly known till .
the time of Bafll Valentine, who lived about the end
of the 15th century. In his work, entitled Currus
Triumphalis Antimonii, he has detailed all that was
then known, of this metallic fubftance, and he has par-.
ticularly defcribed the procefs by which it is extracted
from its ore.
No fubftance has been more the fubjedl of invefti-
gation than antimony, and on no fubjedl, perhaps,
has there been fo much written. The alchemifts re¬
garded antimony as peculiarly appropriate to the ob,
/
CHEMISTRY.
63?
Antimony, je& of their refearches.
See. ' ‘  
167S
Ores.
1677
Analyfis.
1678 '
Properties,
Their labours on this fubjeft
were almoft incredible ; and indeed this is fcarcely to
be wondered at, fince it appears that they were infpired
with the hope of making, by its means, the fortunate
difeovery of the univerfal medicine. It was therefore
tortured and tried in every poflible way, to obtain the
objeft of their refearches j and on this account it is al¬
moft impoftible to reckon up the number of medicinal
preparations which were propofed and employed with
this metal and its ores. It is owing to thefe views and
refearches, concerning antimony, that its nature and
properties are now fo fully known.
2. About the end of the 17th century, Lemery pub-
liftied a treatife, w'hich was the firft correft and ra¬
tional account of antimony. In this he arranged and
detailed the difeoveries of his predeceflbrs, and added
fome of his own, with a number of curious experiments
and accurate procefles for many of the preparations of
antimony and its fulphuret. Mender afterwards pub-
liftied a very complete hiftory of all the fafts that were
then known concerning antimony j and it has been
lince examined by more modern chemifts; among
whom Bergman, Scheele, Berthollet, Prouft, and The-
nard, are the principal writers on this fubjeft.
3. Antimony exifts in nature in four different ftates:
In the ftate of native antimony, that of fulphuret, hy-
drofulphuret of the oxide of antimony, and muriate.
Native antimony is eafily diftinguiftied ,.by its colour
and brilliancy. It has been found in Sweden and in
France. The moft common ore of antimony is the
fulphuret, w'hich is of a grayifh colour, and flams the
fingers. It is fometimes cryftallized in fquare prifms,
which are {lightly rhomboidal, and terminated by four-
fided pyramids. The hydrofulphurated oxide of anti¬
mony is in fhining filaments, of a deep red colour, dif-
pofed in rays going from a common centre, adhering
to the furface or cavities of the fulphuret. The muriate
of antimony, which is a rare production, is of a bril¬
liant, pearly-white colour, in the form of fmall diver¬
gent needles, fomewhat refembling radiated zeolite.
4. To obtain the pure metal from the fulphuret of
antimony, the ore is firft roafted, to feparate the greateft
part of the fulphur. It is then mixed with its owm
weight of black flux, formed into a pafte with oil,
and expofed to a ftrong heat in a crucible, at the bot¬
tom of which the metal is found reduced. By a fhorter
procefs, eight parts of fulphuret of antimony, fix of
tartar, and three of nitre, reduced to powder, and well
mixed, are projefted in fmall quantities into a red-hot
crucible. At each projeCfion there is a ftrong detona¬
tion j the tartar forms, by means of the nitre, a black
flux, and the fulphuret being burnt, the metal is fiifed,
but not oxidated, on account of the charcoal of the tar¬
tar with which it is furroundqd, and the liquid alkali
which covers it. The whole is then fufed in a conical
iron pot •, and, when it is cool, the metallic antimony
is found at the bottom, marked on its furface with
needle-ftiaped cryftals, .arranged in the form of a ftar.
5. Antimony, in a ftate of purity, is of a brilliant
white colour, having a good deal of refemblance to
that of filver or of tin. It has a lamellated texture,
compofed of plates w’hich crofs each other in all di¬
rections. It exhibits fometimes perceptible traces of
cryftallization. The form of the cryftals, which was
difeovered with di£dculty by Haw#, on account of its
complicated ftructure, is the octahedron, computed of Antimony,
a great number of regular tetrahedrons. Antimony , ,
has a very perceptible tafte and fmell, and particular¬
ly if it is rubbed for fome time on the hands. The
fpecific gravity is 6.702i It is very brittle, fo that it
can be reduced to pow^der, which is of a grayith w’hite
colour. 1579
6. Antimony undergoes no change by being expo-AChonc*
fed to the air, nor is there any perceptible aCtion be- water-
tween antimony and water in the cold ; but when
water comes in contaCl with antimony red hot, it is
inftantaneoufly decompofed, and accompanied with a
violent detonation, and a very brilliant white flame.
Accidents of this kind have happened, attended with
confiderable danger. 1680
7. When antimony is heated to the temperature of Oi heat,
8o8°, it melts. If the heat be continued after its fu-
fion, it is fublimed, and if the procefs be performed in
clofe velfels, it is condenfed in fhining cryftallized
plates. If it be allowed to cool flowly, and part of it
be poured off when the furface becomes folid, the ca¬
vity is lined with pyramidal cryftals, compofed of
fmall o&ahedrons. x<>8r
8. When antimony is kept in fufion in the open Oxides,
air, it rifes in the form of white vapour, wdiich is pre¬
cipitated on the furface of the metal or upper part of
the crucible, and cryftallizes in long prifms, or in
fmall, white, brilliant needles. This is an oxide of
antimony, which was formerly called argentine flow¬
ers, or fnow of regains of antimony. By this procefs
it is found, that the antimony has acquired an addition,
of weight of about 50 per cent. This oxide may be
obtained, by expofing the antimony in a crucible to
a w'hite heat, and then by fuddenly agitating it in con-
taft with air, it takes fire with a kind of explofion, and
burns with a white light.
Thenard, in his refearches concerning antimony,
diftinguifhes fix different degrees of oxidation of this
metal. But in a memoir on the fame metal by Prouft,
he confiders that the oxides of antimony may be redu¬
ced to two. According to the experiments of this
chemift, 100 parts of antimony treated with nitric
acid in a retort, uniformly afford 130 of a yellow-
oxide in the ftate of powder. It is reduced to 126 by
wafhing with water before drying it, becaufe the ni¬
tric acid diffolves a fmall proportion. This oxide is
not reduced by being expofed to a red heat, but it is
fublimed, and condenfed in clofe veffels, in groups of
cryftals. It is infoluble in water. It is the fame-
oxide which was formerly diftinguiilied by the name of
argentine flowers. The component parts of this oxide,-
according to Prouft, are,
Antimony 77
Oxygen 23
IO° ^ ,
* Jour, dr
The oxide with a fmaller proportion of oxygen, \%Pbyfique,
formed by diffolving antimony in muriatic acid ; and •iv* P-330>
by adding water to the folution, a white powder is
precipitated, xvhich being wafhed, is feparated from
any acid that may adhere to it. To purify it Hill
more, it is to be boiled with carbonate of potafh, and
afterwards wafhed, and dried on a filter. This oxide is
of ayellowifli white colour, and has little brilliancy 5 it
melts
638 C H E M
Antimony, melts at a moderate red heat, and when it is allowed
. &c‘ to cool, it cryftailizes on the furface. The cryftals
'' ’’ are of a yellowilh white colour, which are thrown to¬
gether in heaps, in a radiated form. This oxide was
formerly known by the name of powder of algaroth.
Its component parts are,
Antimony 81.5
Oxygen 18.5
* Journ. de 100.0
Pbyftque,
Iv. p. 330. There is no a£lion between antimony and azote,
i(Jg;5 hydrogen, or carbone.
J*liofphuret. I0* Antimony enters into combination with phof-
phorus, and forms with it a phofphuret. Equal parts
of phofphoric glafs and antimony are fufed together
in a crucible, or with the addition of ^ of charcoal,
or by proje6ting pieces of phofphorus on the metal in
fufion in a crucible ; and thus a phofphuret of anti¬
mony is obtained. This phofphuret has a metallic
luftre, is brittle, and has a lamellated frafture. When
it is placed on burning charcoal, it melts, gives
out a fmall green flame, and is converted into the
1683 white oxide of antimony, wdiich is fublimed.
iulphuret. j j. Antimony combines very readily with fulphur,
and forms with it an artificial fulphuret, which is ex-
aftly fimilar to the native fulphuret. It is formed by
mixing the antimony and the fulphur together, and
fufing them in a crucible. This fulphuret is of a
brilliant gray colour, is more fufible than the metal
itfelf, and by flow cooling, may be obtained in cryftals.
The component parts of the fulphuret, according to
Prouft, are,
Antimony, 75.1
Oxygen, 24.9
I 00.0
■1684
Oxideswitji 12. The yellow oxide of antimony combines with
iulphur. different proportions of fulphur, and forms compounds
of different colours, and wrhich were formerly diftinguifh-
ed by different names. With eight parts of the oxide
and one part of fulphuret, a red coloured, femitranf-
parent mafs is obtained, which was formerly called glaft
of antimony. When two parts of fulphuret are added
to eight parts of the oxide, a yellowifh mafs is formed,
which was known by the name of crocus meta/iorum.
Six parts of oxide and one of fulphur, form a dark red,
opaque mafs, with a vitreous fradture, which is the true
liver of fulphur. In thefe combinations, the fulphur
deprives the oxide of part of the antimony, and com¬
bines with it, forming a fulphuret. This fulphuret then
} Ibid. Iv. combines with the oxide if.
13‘ Antimony enters into combination with the
acids, and forms falts. It alfo forms alloys with many
mms. 0f metals The affinities of antimony and of its
oxides are, according to Bergman, in the following
order:
Antimony.
Iron,
Copper,
Tin,
Lead,
Nickel,
Oxide of Antimony.
Muriatic acid,
Oxalic,
Sulphuric,
Nitric,
Tartaric,
Oxide of Antimony.
Sacladlic,
Phofphoric,
Citric,
Succinic,
Fluoric,
Arfenic,
Ladlic,
Acetic,
Boracic,
Prufiic,
Carbonic.
I. Salts of Antimony.
1. Sulphate of Antimony.
Sulphuric acid has no adlion on antimony in the
cold. At a boiling temperature the acid is decompof-
ed ; fulphurous acid gas is emitted with effervefcence,
and if diftilled in a retort to drynefs, fulphur is fublim¬
ed. There remains a white oxide of antimony. If
this mafs be waflied with w^ater, the acid which adheres
to it is carried off, with a fmall portion of the oxide,
and what remains is the white oxide, which is infoluble.
By adding a large quantity of water to the folution,
the oxide which it had carried off is precipitated ; but
this folution being evaporated yields no cryfials. It is
decompofed by the eaiths and the alkalies, which pre¬
cipitate a white oxide. Sulphuric acid, therefore, oxi¬
dates antimony, but does not feem to have the property
of forming a fait.
2. Sulphite of Antimony.
Sulphurous acid with the affiftance of heat, is de¬
compofed by antimony. The metal is oxidated, and
there is formed a fulphite of antimony. This fait may
be alfo obtained by adding fulphurous acid to the fo¬
lution of antimony in muriatic acid. A white preci¬
pitate appears, which is infoluble, of an acrid, bitter
tafte, and is decompofed by heat. When it is diftilled
in clofe veffels, it yields a little fulphurous acid, then
fulphuric acid, and the refiduum is a reddifh brown
mafs, which is foluble in fixed alkali, and may be preci¬
pitated by means of muriatic acid, into a hydrofulphu-
ret of antimony.
3. Nitrate of Antimony.
Nitric acid is rapidly decompofed by antimony, even
in the cold. There is evolved a great quantity of ni¬
trous gas, and fometimes the rapidity of the oxidation is
fuch, that it is accompanied with a&ual combuftion.
The water alfo is partially decompofed. The anti¬
mony is converted into white oxide. The hydrogen
of the water combines with the azote of the acid, and
forms ammonia, which combines with part of the nitric
acid, and the compound is nitrate of ammonia. The fmall
quantity of oxide of antimony which is diffolved in nitric
acid, is precipitated by water, fo that it adheres very
ilightly to the acid.
4. Muriate of Antimony.
Muriatic acid a6ts on antimony very feebly. By di-
gefting the metal with the acid for a long time, it dif-
lolves a fmall quantity, and the folution becomes of a
yellowifti colour. The white oxide is more foluble in
this
I S T R Y.
Antimony,
Silver,
Bifmuth,
Zinc,
Gold,
Platina,
Mercury,
Arfenic,
Cobalt,
Sulphur.
Antimony,
Sc.
1
S T R Y.
C H E M
Antimony, this acid, and forms with it a colourlefs folution. The
firft folution yields cryftals by e\'aporation, in the form
0f fmall needles, which are deliquefcent, and fublimed
by heat, and are precipitated and decompofed by wa¬
ter. The folution formed with the oxide is fixed in
the fire, and cryflallizes in brilliant plates. It is alfo
decompofed by water. Muriatic acid diffolves more
readily the fulpburet of antimony, for it does not re¬
quire the aid of heat. There is difengaged a llrong
odour of fulphurated hydrogen gas. When the mix¬
ture is heated, the whole of the metal is diffolved.
Nitromuriatic acid dilfolves antimony more readily
than any of the acids w'hich have been mentioned.
This folution is colourlefs. The muriate of antimony
which remains after the evaporation, by being diftil-
led, comes over of a thicker confiftence, in proportion
as it is concentrated. This muriate of antimony was
formerly called butter of antimony. It is of a grayifh
white colour, and fometimes cryftallizes in four-fided
prifms. It is deliquefcent in the air, and extremely
cauflic and corrofive. When it is diluted with umter,
a white powder is precipitated, which is the powder of
algarotb.
5. Fluate of Antimony,
6. Borate of Antimony.
Fluoric and boracic acids have no aflion on anti¬
mony, but combine with its oxide, or precipitate it from
its folution in acids, in the form of white powder, form¬
ing a fluate or borate of antimony.
7. Phofphate of Antimony.
Phofphoric acid combines writh the oxide of anti-
piony. The folution, by evaporation, yields a blackifli
green mafs.
8. Phofphate of Lime and Antimony.
1685 ... . .
James’s This triple fait is formed by calcining together
powder. equal parts of fulphuret of antimony and the aflies of
bones ; or, according to the procefs recommended by
Mr Ghenevix, by diffolving wrhite oxide of antimony
. and phofphite of lime in equal parts in muriatic acid $
and then by adding this folution to a fufficient quanti¬
ty of diftilled w^ater, which contains pure ammonia.
A precipitate is formed in the ftate of white powrder.
This powder is nearly infoluble in water. It has been
long known as a diaphoretic and emetic, under the
name of James',s powder. According to the arialyfis
of Dr Pearfon, it is compofed of
Phofphate of lime, 43
Oxide of antimony, 57
100
9. Carbonate of Antimony.-
Unknown.
10. Arfeniate of Antimony.
By digefting together arfenic acid and antimony,
a white powder is obtained, which is arfeniate of
antimony. Muriatic acid difiblves this powder, but it
may be feparated by adding water. This fait may be
formed alfo, by adding an alkaline arfeniate to the folu¬
tion of antimony in muriatic, tartaric, or acetic acids.
I
639
, Antimony*
11. Molybdate of Antimony. &c.
Muriate of antimony is precipitated by molybdic v *
acid ; and if the acid be not in excefs, the precipitate
is white.
I 2. Acetate of Antimony.
Acetic acid diflblves a fmall portion of the oxide of
antimony, and according to fame, yields fmall cryilals.
The acetate of antimony has been employed as an
emetic.
13. Oxalate of Antimony.
Oxalic acid combines with the oxide of antimony,
and the folution affords cryftals in the form of fmall
grains, which are fcarcely foluble in water.
14. Tartrate of Antimony.
Tartaric acid alfo combines with a fmall portion of
the oxide of antimony, and affords a fait which affumes
the form of jelly.
15. Tartrate of Potafh and Antimony.
This triple fait wras formerly prepared by boiling to¬
gether the preparation of what was called crocus me-
tallorum, and tartar, in water. But if the white oxide Tartar'
be mixed with its own weight of tartar, and the mix-emetic,
ture boiled in 10 or 12 parts of water, till the tartar
be faturated, and the folution filtered and evaporated,
cryftals are obtained, which are cryftals of the tartrate
of potafti and antimony, which have been long and better
known by the name of tartar emetic. This fait is of
a white colour, and it cryftallizes in regular tetrahe¬
drons. It efflorefces by expofure to the air, and is fo¬
luble in 80 parts of cold, and in half that quantity of
water at the boiling temperature. When it is expofed
to heat, it is decompofed. It is alfo decompofed by
the alkalies and their carbonates.
According to the analyfis of Thenard, this fait is
compofed of
Antimony, 38
Acid, 34
Potafti, 16
Water, 8
96, lofs 4. *
* Ann. de
This fait has been greatly employed as a diaphore-C/5'CT:..
tic and emetic, from which property it has derived
its name. An account of the mode of preparing a fi-
milar powder, which, it is faid, was invented by an.
earl of Warwick, and became famous in Italy as a
powerful and effedlual medicine, was publiftied in
Italy, in the year 1620. The preparation of tartar
emetic itfelf was firft publiftied in 1631.
16. Benzoate of Antimony.
Benzoic acid combines with the oxide of antimony,
and by evaporating the folution, cryftals are obtained.
This fait is not altered by expofure to the air, but it
is readily decompofed by heat.
II. Aflion of Alkalies, Stc. on Antimony.
. ... 16S8
I. All the alkalies have a peculiar a&ion on the Alkalies,
fulphuret of antimony.- Sulpkvuet of antimony and
potafti
640 C H E M I
Antimony, potafli form a preparation which is known by the name
&'c~ of hermes mineral, a name which it derives from the
red animal called hermes. This is prepared in the dry
way by mixing together one part of fulphuret of anti¬
mony and two of potafh, and in proportion to the
quantity of fulphuret, add a lixteenth part of fulphur.
Fufe the mixture in a crucible, and pour it into an
iron mortar. When it is cool reduce it to powder,
and boil it in water ; filter the liquid, and as it cools,
a reddilh brown powder is depofited. Wafh the pre¬
cipitate, firft with cold, and then with boiling water,
till it comes off infipid. It may be prepared in the
humid way, by boiling 10 or 12 parts of pure liquid
alkali with two of fulphuret of antimony, for half an
hour, and then filtering the liquid j the kermes is de¬
pofited as it cools.
The compound which is firft formed, is a hydroful-
phuret of potalh and antimony. When boiling water
is added in fufficient quantity, the whole is diffolved,
but the folution becomes turbid by cooling, and di¬
vides into two parts •, the one which is depofited
in the form of a reddifh brown powder, is the kermes
mineral, and the other, which remains in folution,
containing a fmaller proportion of fulphur and oxide
of antimony than the former, has been diftinguifiied
by the name of golden fulphur. The caufe of the fe-
paration is, that the alkali, if it is not in great quan¬
tity, cannot hold the fulphurated oxide of antimony in
folution while it is cold. What remains in folutian af¬
ter the fpontaneous precipitation, contains a greater
proportion of fulphur, and lefs of the oxide of anti¬
mony. When an acid is added to this folution, ano¬
ther precipitate is formed, which is of an orange yel¬
low colour, from the greater proportion of fulphur,
and on this account has been called golden fulphur.
Kermes mineral, or the hydrofulphuret of antimony,
according to Thenard, contains the following propor¬
tions.
Brown oxide of antimony, ’•jl.'pGo
Sulphurated hydrogen, 20.298
Sulphur, 4-i56
Water and lofs, 2.786
100.000
From the analyfis of the fame chemift, the golden
fulphur or fulphur auratum, is alfo a hydrofulphuret,
having a greater proportion of fulphur, and a fmaller
proportion of the oxide. The component parts are the
following.
* Ann. dc
Chitn. xxxii.
p. 277.
1689
Earths
16 90
Salts.
Brown oxide of antimony, 68.300
Sulphurated hydrogen, 17.877
Sulphur, 12.000
98.177 *
2. The oxide of antimony has the property of com¬
bining with fome of the earths during their vitrifica¬
tion, and communicating to them different (hades of
colour, more or lefs yellow and orange.
3. Mofl: of the falts have a peculiar aft ion on anti¬
mony or its fulphuret. By fufing in a crucible two
parts of fulphate of potafh and one of antimony, the
metal difappears, and a vitreous mafs of a yellow co-
z
S T R Y.
lour is formed, which has a caiuftic property. Dif-Telluminv
folved in hot water, it affords, on cooling, a hydro-
fulphuret of antimony. The antimony has carried off M v "",_J
the oxygen of the acid, and combined in the itate of
oxide, with the fulphuret of potafh, which is formed
by the fulphur of the acid uniting with the potafh du¬
ring the procefs.
The nitrates have a powerful aftion on antimony
and its fulphuret. A mixture of two or three parts
of nitrate of potafh and one of antimony in fine pow¬
der, well rubbed together in a mortar, produces a
lively detonation, by throwing it on burning coals,
or projefting it into a red-hot crucible, or heating it
to rednefs in a clofe veffel. This detonation is accom¬
panied with a bright white flame j and the antimony
is flrongly oxidated by the oxygen of the nitre, which
is decompofed, and reduced to its alkaline bale. The
refiduum of this detonation is a white fcorified mafs,
which being wafhed with water, leaves a portion of
the oxide of antimony united to a fmall quantity of
potafh, and affords befides, another compound, with
more of the alkali. The white matter which is firft
depofited, has been called ivafked diaphoretic antimo¬
ny. The water which remains holds in folution a por¬
tion of metallic oxide, united to the potafh of the
nitre. The oxide in this cafe performs the part of an
acid. This compound has been found fufceptible of
cryftallization. It is decompofed by acids, and the pre¬
cipitate from it, which is an oxide of antimony, has
been diftinguifhed by the names of cerufe of antimony,
magijlery of diaphoretic antimony, and pearly matter of
Kerhringius.
When equal parts of nitre and fulphuret of antimo¬
ny are treated in the fame vvay, a vitrified mafs is ob¬
tained, fimilar to w hat has been already defcribed, by
the name of liver of antimony.
III. Alloys.
Antimony enters into combination with the metals,
and forms alloys with them, fome of which are of con-
fiderable importance. But the alloys of antimony,
with the metals already defcribed, are either little
known, or have been applied to no ufe. The alloys
of cobalt and nickel, with antimony, have not been
examined. With manganefe antimony forms but an
imperfeft alloy, and the compound of antimony and
bifmuth is very brittle.
Befides the various preparations of antimony ufed inufesof
medicine, which are now comparatively but few in antimony,
number, it is much employed in many arts. In the
metallic ftate it is of the greateft importance as an al¬
loy with other metals which will be afterwards men¬
tioned. In the ftate of oxide, it is much ufed in the
fabrication of coloured glafs, and of enamels for pot¬
tery and porcelain j particularly in forming different
fliades of brown, orange, and yellow colours. The
oxide is mixed with different other metallic oxides, to
produce various fhades of cdlour.
Sect. XIII. Of Tellvrivm and its Combinations.
1694
I. In the year 1782, Muller of Richenftein, in examin-Hiflory,
ing a gold ore, diftinguifiied by the names of aurum
paradoxum and aurum problematicum, conjeftured that
•it
CHEMIST
1693
I’rapertxes.
1694
Atlion of
heat.
I <595
Sulphuret.
it contained a peculiar metal. Bergman, to whom
this mineralogift had fent a fpecimen of the mineral,
could not, from the fmall quantity which he had re¬
ceived, afcertain whether it was really a new metal,
or merely antimony, with which it poffiefles fome com¬
mon properties. He inclined however to the former
opinion. This mineral was analyzed by Klaproth
in the end of the year 1797, the account of which was
publiihed in 1798. By this analyfis the conjefture
of Muller was verified, and to the new metal Kla¬
proth gave the name of tellurium.
2. This metal has been found in four different mine¬
rals. Firft, in that in which Klaproth firft dete&ed it,
which is called white gold ore, a mineral found in the
mountains of Fatzbay in Tranfylvania. In this mi¬
neral the tellurium is combined with iron and gold.
The fecond is what is called graphic gold ore, which
is compofed of tellurium, gold, and filver. The third
is known by the name of yellow gold ore of Nagyag.
This mineral contains, befides tellurium, gold, lilver,
and a little fulphur. The fourth is a variety of the
laft, and is denominated gray gold ore. Befides the
metals in the former, it contains a little copper. To
obtain the metal from the ore, a quantity of it is {light¬
ly heated with fix parts of muriatic acid, and having
added three parts of nitric acid, it is then boiled. A
confiderable eftervefcence takes place, and the whole
is diffblved. The folution being diluted with diftilled
water, is mixed with a folution of cauftic potafli, to
diffblve the precipitate; and there remains only a brown,
flaky matter, formed of the oxides of gold and iron.
The alkaline folution of the oxide of tellurium is mix¬
ed with muriatic acid, to faturate the potafli, and there
is depofited a copious, very heavy, white powder. By
forming this powder into a pafte with oil, and heating
it to rednefs in a fmall glafs retort, the metal is ob¬
tained, partly fufed and cryffallized at the bottom of
the retort, and partly fublimed at the upper part.
4. Tellurium is of a white colour, fomewhat refem-
bling lead, and has a confiderable luftre. It is very brit¬
tle, and may be eafily reduced to powder. It has a
lamellated texture, fimilar to antimony. By flow cool¬
ing it aflumes a cryftalline form, efpecially on the fur-
face. Its fpecific gravity is 6.115. It is one of the
moft fufible of the metals, and when heated in clofe
veflels, it boils readily, and is fublimed in the form of
brilliant globules, which adhere to the upper part of
the vefiels.
5. When tellurium is heated by the a£lion of the
blow-pipe on charcoal, it burns, after being melted,
with a lively flame, of a blue colour, and green at the
edges. It is entirely volatilized in the form of a gray-
ilh white fmoke, diffufing a fetid odour, which Kla¬
proth compares to that of radifhes.
The oxide of tellurium is very fufible. By heating
it in a retort, a yellow, ftraw-coloured mafs is obtain¬
ed, which aflumes a radiated texture on cooling. When
the oxide is heated on charcoal, and furrounded with
it, it is fo rapidly reduced, that it is accompanied with
a kind of explofion.
6. Tellurium enters into combination with fulphur,
and forms wdth it a fulphuret. This fulphuret is of a
grayilh colour, of a radiated ftru&ure, and is eafily
cryftallized.
Vol. V. Part II.
R Y.
I. Salts of Tellurium.
I. Sulphate of Tellurium.
641
Tellurium,
&c.
One part of tellurium mixed in the cold, in a clofe
veflel,with loopartsofconcentratedfulphuric acid,com¬
municates to it a beautiful crimfon colour. By adding
water drop by drop to this folution, the colour vaniflie?,
and the metal is depofited in the form of black flakes.
When the folution is heated, the colour alfo difappears,
and the oxide of tellurium is gradually precipitated in
the ft ate of white powder; but when diluted fulphuric
acid is employed, with the addition of a fmall quantity
of nitric acid, a larger portion of tellurium is diffblved".
The folution is tranfparent and colourlefs, and is not
decompofed by adding water.
2. Nitrate of Tellurium.
Nitric acid readily diffolves tellurium, and forms a
tranfparent, colourlefs folution, which being concen¬
trated, fpontaneoufly affords fmall, light, white, needle*
fhaped cryftals, difpofed in a dendritical form.
3. Muriate of Tellurium.
Nitromuriatic acid very readily diffolves tellurium,
which is precipitated by adding a confiderable quan¬
tity of water in the form of oxide. This is a white
powder, which is foluble in muriatic acid.
1 he infufion of nut-galls added to folutions of tellu¬
rium in acids, occafions a flaky precipitate, which is
of a yellow colour.
II. Ablion of Alkalies and Earths.
1. All the pure alkalies precipitate the folutions of tel- l69/5
lurium in acids, in the form of white oxide. With an Alkahe?*
excefs of alkali the precipitate is re-diffolved. With the
alkaline carbonates a precipitate is obtained, which is
much lefs ioluble in excefs of alkali.
2. The alkaline fulphurets added to folutions of tellu¬
rium in acids, produce a brown or black precipitate,
as the metal is more or lefs oxidated. This precipi¬
tate fometimes refembles the hydrofulphurets of anti¬
mony. The hydro,fulphuret of tellurium thus formed,
expofed to heat on burning coals, burns with a fmall
blue flame, and is volatilized in white fmoke. No
precipitate is formed by the prufliate of potafti. 1697
3. The aftion of the oxide of tellurium with the earths Earth--
is not known; but from its great fufibility, it has been
fuppofed that it is fufceptible of forming a vitreous
matter with the earths, and communicating to them a
ftraw colour.
III. Aflion of Metals.
The alloys of tellurium are unknown.
I ellurium is feparated from its folutions in acids, by Precipita-
zinc and iron, in the form of fmall, black flakes, which ted hY zinc
may be reduced to the metallic ftate on burning char- and iron'
coal, or even by Ample friaion. Antimony caufes a
fimilar precipitation in a folution of. nitrate and ful-
phate of tellurium. Tin produces a fimilar effebt. ^
Tellurium has hitherto been found in fuch fmall Ufe>.
quantity, that it has not yet been applied to any ufe.
Were it found in abundance, it has been fuppofed,
from its eafy fufibility, that it might be of confider¬
able importance in fome of the arts.
4 M
Sect.-
642
CHEMISTRY.
Mercury,
Sec. Sect. XIII. Of Mercurt and its Combinations.
170O Mercury appears to have been known from the
e&rlieft ages. By comparing its properties with filver,
and being in the fluid date, it has been called quick-
fiver. Mercury was long the fubjeft of the refearches
of the alchemifts, with the view of difcovering the me¬
thod of tranfmuting it into gold or filver. It was fup-
pofed to approach lb near to thefe metals, particularly
to the latter, in its nature, that all that was wanted for
this tranfmutation, was to fix it, or to bring it to the iolid
flate. In confequence of the numerous experiments to
which it was iubje£ted, and the great varieties of
forms it affumed, they regarded it as the principle of
all other bodies, and one of the elements of nature.
It was fuppofed to exift in all metals, and alfo to form
one of the component parts of many bodies. Hence,
according to this theory, there were two kinds of mer¬
cury $ the one the principle of a great number of
bodies, and the other common mercury, or the metal
known by that name. Hence, according to Beecher,
• it was called the mercurial principle, or the mercurial
earth. But however extravagant the refearches of the
alchemifts may now be confidered to have been, it is
to their labours that chemiftry is indebted for the know¬
ledge of many important properties and combinations
of this metal.
Ore1701 2* Mercur7 found in f°ur different ftates. In
the metallic ftate, alloyed with other metals, combin¬
ed with fulphur, and with muriatic acid. l. Native or
virgin mercury is found in the cavities or clefts of
rocks, in ftrata of clay, or of chalk, in the form of
liquid globules, which are eafily diftinguilhed by their
brilliancy. 2. It is found more frequently alloyed with
other metals, or, as it is called when mercury is com¬
bined with a metal, amalgamated, and moft frequently
with filver. 3. A frequent ore of mercury is the red ful-
phuret, which is known by the name of cinnabar.
The fulphuret of mercury is of various colours, from
vermilion red to brown. Sometimes it efflorefees on
the furface of the ore, when it is called fowers of cin¬
nabar, or native vermilion. 4. The fourth ore of this
metal is the muriate. This fait is white and brilliant,
and of a lamellated ftrudture.
~"alyl!s 3* Native mercury is frequently alloyed with other
metals •, it is therefore of importance to be able to af-
certain the proportions. For this purpofe it is to be
difiblved in nitric acid. If it contain gold, this me¬
tal remains in a ftate of pow’dtr at the bottom of the
veffel. If alloyed with bifmuth, it may be precipi¬
tated with water, which does not feparate the oxide of
mercury. Silver is detedled by precipitating the folu-
tion by means of muriate of foda. The muriate of
filver and the muriate of mercury fall down together j
' but the latter being more foluble in water than the
former, may be eafily feparated.
The fulphuret of mercury may be decompofed by
boiling it with eight times its weight, of a mixture of
three parts of nitric, and one of muriatic acid} the me¬
tallic partis diffolved, and the fulphur remains in the
1703 ftate of powder.
Todifcover It may be known whether the mercury has been a-
its purity, dulterated with other metals, by its dull and lefs
brilliant luftre, and by its foiling the hands, or white
bodies on which it is rubbed, and by its dividing with Mercury,
more difficulty into round globules, which appear ^c- ,
flat and uneven, adhere to the veffels in which they
are agitated, and when poured along a fmooth fur-
face, by their dragging a tail. Mercury is alfo im¬
pure, when the globules do not readily run together,
and when it is agitated with water, feparating from it
a black powder. . ^ . . I7C4
To procure mercury in a i'tate or purity, or to re-purifjca<(
vive it, as it is called, two parts of cinnabar and onetion.
of filings of iron are well triturated together, and di-
ftilled in an iron retort, introducing the beak of the re¬
tort into a receiver, with water. The iron has a great¬
er affinity for the oxygen and the fulphur of the
mercury than the latter. The mercury, therefore,
rifes in vapour, and is condenfed by the water. There
remains in the retort a fulphuret of iron, in which the
metal is a little oxidated. The mercury thus obtain¬
ed, being dried and paffed through a fkin, is very pure
and brilliant. i7oy
4. Mercury is of a white colour, is one of the moft Properties,
brilliant of the metals, and when its furface is clean
and not tarniffied, makes a good mirror. Next to
gold, platina, and tungften, it is the heavieft of the me¬
tals, having a fpecific gravity =13.568. It has no
perceptible tafte or fmell.
5. At the ordinary temperature of the atmofphere
mercury is always in the liquid ftate $ but when it is
expofed to a degree of cold equal to —390 it becomes
folid. This was firft difeovered in the year 1759 by
the academicians of Peterfburgh. Similar experiments
have fince been frequently repeated. In I772> Pallas
fucceeded in the congelation of mercury at Krafno-
jark, by a natural cold equal to —554‘° Fahrenheit.
Mercury was alio congealed by a natural cold in 1775
at Huc-lfon’s bay. The freezing of mercury is now a
common experiment by means of artificial cold, and
the method of producing this has been already de-
feribed, in treating of freezing mixtures. In feme
experiments which have been made on the congelation
of mercury, it was remarked, that a flight fhock was
communicated to the perlon who held the tube con¬
taining the metal, by its fudden contraftion at the mo¬
ment it became folid. Mercury cryftallizes in very
fmall o&ahedrons. It appears to be malleable, for by
ftriking it with a hammer in the folid ftate, it was flat¬
tened and extended.
6. At the temperature of 66o° mercury boils, and Adtion of
is then converted into vapour. This vapour, like heat,
common air, is invifible and elaftic. When mercury
is expofed to the air, the furface becomes tarniffied,
and is covered with a black powder. This change is0xi^7
owing to the abforption of the oxygen of the air, and
the converfion of the mercury into an oxide. This
procefs is greatly promoted by applying heat to the
mercury, or by ffiaking it, fo that it may be brought
in contaft with the air. To this black powder, which
is the firft degree of the oxidation of the metal, the
name of ethiops perfe w as formerly given, becaule it is£iaCR
obtained without the affittance of any other fubftance.
According to Fourcroy, this oxide contains
Mercury, 96
Oxygen, 4
100
Ey
CHEMISTRY.
Mercury,
&c.
1709
Red.
1710
Aftion of
hydrogen.
1711
Fhofphuret
- 1712
Sulphuret.
By a ftrong heat the oxygen is driven off, and the
mercury is reduced to the metallic ftate : but when
this oxide is expofed to a more moderate degree of
heat, it combines with more oxygen, and is converted
into the red oxide, fo called from its colour. This
oxide may alfo be obtained, by expofing a quantity of
mercury for fome length of time in a veffel provided
with a long narrow neck, by which means the vapours
of the mercury are prevented from efcaping, while the
air is admitted. By this procefs the mercury is alfo
converted into the red oxide ; and, obtained in this way,
it was formerly called precipitate per fe, or red precipi¬
tate. This oxide may alfo be obtained by diffolving
mercury in nitric acid, evaporating to drynefs, and ex-
pefing the mafs to a very llrong heat, to drive off the
acid. What remains being reduced to powder, is the
red oxide of mercury, or red precipitate. This oxide,
according to Fourcroy, contains one-tenth of its weight
of oxygen. It is of an acrid difagreeable tafte, and has
fo powerful an effeft upon animal matters, that it
may be confldered as a poifon. It corrodes the Ikin
with which it comes in contaft. When this oxide is
expofed to heat, it is decompofed ; part of its oxygen is
given out, and it is converted into the black oxide.
Even by expofure to the light of the fun, this change
is effefted, as it paffes through different {hades of co¬
lour.
7. Mercury does not enter into combination with
azote, hydrogen, or carbone \ but if hydrogen gas be
kept in contadt witta the red oxide, it is gradually con¬
verted into the black oxide. If hydrogen gas be made
to pafs through a tube heated to rednefs, containing red
oxide of mercury, a detonation takes place. The oxygen
and hydrogen combine together to form water, while
the mercury is reduced to the metallic ftate. This oxide
may be alfo reduced by means of charcoal, with the af-
fiftance of heat. The oxygen of the oxide combines with
carbone, and forms carbonic acid, and the mercury is re¬
vived.
8. Phofphorus combines with mercury with dif¬
ficulty. Pelletier took equal parts of phofphorus and
red oxide of mercury, and introduced them into a ma-
trafs, to which he added a little water, to cover the
mixture. It was expofed to the heat of a fand bath,
and agitated from time to time. The oxide foon be¬
came black, and united to the phofphorus. The wa¬
ter retained phofphoric acid 5 fo that it appears to be
a compound of phofphorus and the black oxide of
mercury. The phofphuret of mercury thus formed,
becomes foft in boiling rvater, and acquires fome con¬
fidence in the cold. When it is heated, it is decom¬
pofed. The phofphorus and the mercury are feparately
emitted. Expofed to a dry air, it diffufes white va¬
pours, which have the odour of phofphorus.
9. Mercury combines readily with fulphur, either
by fimple trituration in the cold, or by the aflion of
heat. One part of mercury and two of fulphur, tritu¬
rated together in a mortar, the mercury foon difappear-
ing, form a black powder, which was formerly dif-
tinguifhed by the name of ethiops mineral. Fourcroy
is of opinion, that in this procefs the mercury is oxi¬
dated, and the fulphur is combined with the black
oxide y in fupport of which, he dates that the ful¬
phur cannot be feparated from the mercury, but by
feme chemical a&ion. Berthollet fuppofes that this
H:
fubftance contains fulphurated hydrogen, and hence Mercury.
it is concluded that ethiops tnineral is a hydrogenous ^'c*
fulphuret of mercury, corapofed of mercury, fulphur,
and fulphurated hydrogen.
When this compound is heated in an open veffel, the
fulphur, which is in a ftate of minute divifion, takes
fire, and is foon reduced to fulphurous acid gas. The
mercury is at the fame time more ftrongly oxidated ;
is converted to a deep violet-coloured powder j and if
in this ftate it be heated in a matrafs, it is fublimed in
the form of a deep red cake, of a brilliant, cryftalline
appearance. This fubftance was formerly called ,
ficial cinnabary or, in the prefent language of die-Cinnabar,
miftry, red fulphurated oxide of mercury. Various pro-
ceffes have been given for the preparation of this fub¬
ftance. Seven parts of mercury fqueezed through
leather to purify it, are to be fufed with one part of
fulphur in an earthen veffel, agitating the mixture till
it is completely reduced to the black fulphurated
oxide. Introduce this into a matrafs, placed in a
crucible furniftied with fand, and expofe it gradually
to the heat of a furnace, which is to be increafed till
the matter is fublimed, and colle&ed at the top of
the veffel. It is then removed, and when the veffel is
broken, a red mafs is obtained, wuth a degree of beauty
and brilliancy in proportion to the temperature which
has been employed, and the fmall quantity of fulphur
which it retains. Fourcroy confiders this as a com¬
pound of fulphur and the red oxide of mercury, but
according to Prouft, it is a fulphuret of mercury •, that
is, a compound of fulphur and metallic mercury. Its
component parts are,
Mercury 85
Sulphur 15
ICO
1714
This fulphuret is of a fine fcarlet colour. It is not Properties,
altered by expofure to the air, and is infoluble in wa¬
ter. The fpecific gravity is 10. When a fufficient
degree of heat is applied to it, it takes fire, and
burns with a blue flame. When reduced to powder, yennflfoa
it is then called vermilion, which is w^ell known as a
paint.
xo. The order of the affinities of mercury is the
following.
Mercury. Oxide of Mercury.
Gold, Muriatic acid,
Silver, Oxalic,
Tin, Succinic,
Lead, Arfenic,
Bifmuth, Phofphoric,
Platina, Sulphuric,
Zinc, Sacla£Hc,
Copper, Tartaric,
Antimony, Citric,
Arfenic, Sulphurous,
Iron. Nitric,
Fluoric,
Acetic,
Boracic,
Pruffic,
Carbonic.
4- M a I. Salts
1716
Affinities,
644
CHEMISTRY.
Mercury,
&c.
1717
Different
fuiphate*.
1718
Prepara¬
tion.
1719
Properties.
I. Salts of Mercury.
1. Sulphate of Mercury.
1. Sulphuric acid forms falts with the different oxides
of mercury, and with different proportions of thefe
oxides, fo that there is a confiderable variety of the
fulphates of mercury. This feems to depend on the
nature of the aftion between fulphuric acid and
mercury, according to the temperature in rvhich the
combination is made, and the quantity of acid em¬
ployed.
2. Sulphuric acid has no effefl on mercury in the
cold ; but if two parts of mercury and three of ful¬
phuric acid be introduced into a retort, and expofed
to heat, an effervefcence takes place, wdth the evolu¬
tion of fulphureous acid gas. If the procefs be flop¬
ped, when the mercury is converted into a white mafs,
and there yet remains part of the liquid, it is found
to be acrid and corrofive, and it reddens vegetable
blues. This is the fulphate of mercury with excefs of
acid. This acidulous fulphate of mercury contains
very different proportions of fulphuric acid, according
to the original quantity employed. If this fulphate
be wafhed with a fmaller quantity of water than is ne-
ceffary for its complete folution, and if this be repeat¬
ed till the water no longer changes vegetable blues,
there remains a white fait without acidity, and which
is much lefs acrid and corrofive than the faline mafs
from which it is obtained. This may be confidered
as a neutral fulphate of mercury.
3. It is of a white colour, cryflallizes in plates, and
in fine, needle-fhaped prifms. The tafle is not acrid.
It is foluble in 500 parts of cold water, and in one
half that quantity of boiling water. When cryftalliz-
ed, it is compofed of
Mercury
Oxygen
Sulphuric acid
Water
75
8
I 2
100
2720
K different
fait by con-
tinuing the
heat.
It is foluble both in cold and hot water, without
being decompofed. The pure alkalies and lime wa¬
ter, occafion a precipitate of a grayifh-black powder.
When fulphuric acid is added, it is then reduced to the
ilate of acidulous fulphate, and its folubility increafes
in proportion to the additional quantity of acid. A
twelfth part of acid renders it foluble in 157 parts of
cold water, and in 33 of boiling water. But if ^ of
this quantity of cold water be added, it combines with
the whole excefs of acid, and forming a liquid of
greater denfity than when it is diluted with 157 parts
of water neceffary for its complete folution, it diffolves
much more of the fulphate of mercury, and brings the
fait to a ftate of greater acidity. It then requires 500
parts of water for its folution.
4. But if the fame proportions of fulphuric acid and
mercury, namely, three parts of acid, and two of mer¬
cury, be expofed for a longer time to the adlion of heat,
a greater proportion of fulphuric acid is decompofed,
and the mercury combines with a greater proportion of
oxygen. The fait thus obtained, poffeffes different pro¬
perties from the former. It cryftallizes in fmall prifms, Mercury,
and when it is neutralized, it is of a dirty-white colour j
but if it be obtained in the dry ftate, it is pure white, ~ *
and in this ftate it is combined with an excefs of acid.
It is then deliquefcent in the air; but, in the neutral
ftate, it undergoes no change. When hot water is ad¬
ded to this fait, it is converted into a yellow powder,
which has been long diftinguilhed by the name of /«r-
fietb mineral.
5. It was formerly fuppofed that turpeth mineral,
wdiich is obtained by the addition of warm water to
this fait, was a ftmple oxide of mercury, without any
portion of fulphuric acid. Fourcroy mentions, that
Rouelle firft conjectured, that it was combined with
a certain portion of the acid, and that his experiments
have verified and confirmed this conjeCture j for in
treating turpeth mineral, after being well w’alhed with
muriatic acid, this folution precipitates by means of
muriate of barytes, a fulphate of barytes from this
bafe. Fourcroy denominates this fait fulphate of mer¬
cury with excefs of acid, or yellow fulphate of mercu¬
ry. It is foluble in 6©o parts of boiling water j but
another fulphate of mercury remains in the folution.
This contains an excefs of acid, and is therefore more
foluble in water. 2712
6. From a feries of experiments which Fourcroy made Three ful-
on this fubjeCl, he concludes, that there are three di-phates-
ftinft fulphates of mercury. 1. The firft is the neutral
fulphate of mercury, which cryftallizes, is foluble in
500 parts of cold water, and forms a copious precipi¬
tate with the alkalies, which is not decompofed by
nitric acid, but forms a mild muriate of mercury wuth
the addition of muriatic acid. 2. The acidulous ful- 172s
phate of mercury, which is more foluble than the for-^f1^1'!0115
mer, is precipitated of an orange colour by means of *
the alkalies. The excefs of acid is removed, and alfo
a portion of the fait, with -j- of the water neceffary for
its complete folution. The neutral fulphate of mercury
remains behind, and is not decompofed by means of
the nitric acid. 3. The third fulphate of mercurys
contains an excefs cf bafe, or of the oxide of mercu-pj1(lte>
ry. It is of a yellow colour, foluble in 200 parts of
water, and is precipitated of a gray colour by the
alkalies. It is decompofed by the nitric acid, and
the muriatic acid converts it into a hyperoxymuriate of
mercury.
2. Sulphate of Ammonia and Mercury.
1724
This triple fait is formed by adding ammonia to aPrepara-
folution of neutral fulphate of mercury. A copioustion.
gray precipitate is thrown down, which, being expofed
to the light of the fun, is partly reduced to the metal¬
lic ftate, and partly to that of a gray powder. This
laft is the fulphate of ammonia and mercury. It is folu¬
ble in ammonia \ and by evaporation, brilliant polygonal
cryftals are formed. Or, if a large quantity of water
be added to the folution, it becomes white and milky, ,
and there is precipitated the fame fait, but without any pr0pert;eSo
regular form. This fait has a pungent, auftere tafte.
When it is heated, it gives out ammonia, azotic gas,
a fmall quantity of metallic mercury, and a little ful-
phite of ammonia. There remains in the retort yellow jyuS,
fulphate of mercury. According to the analyfis ofcompoib.
Fourcroy, this triple fait is compofed of tion.
Sulphuric
Mercury,
&c.
C H E M
Sulphuric acid 18
Mercury 39
Ammonia 33
Water 10
IOO
1727
Prepara-
tion.
1728
Three ni¬
trates.
3. Nitrate of Mercury.
1. Nitric acid is rapidly decompofed by mercury. It
is accompanied with effervefcence, and the evolution
of nitrous gas. The mercury combines with part of
the oxygen of the acid ; it is thus oxidated, and is
then diitolved in the remaining portion of the acid.
This folution of mercury in nitric acid, when it is
made in the cold, is colourlefs, very heavy, and fo
extremely cauftic, that it has been employed as an ef-
charotic, under the name of mercurial water. It
produces an indelible brownilh black fpot on all ani¬
mal and vegetable fubftances. By fpontaneous evapo¬
ration it affords regular tranfparent cryffals, compofed
of two four-fided pyramids, truncated near their bafes,
and on the four angles which refult from the union of
the pyramids. But different cryftals are formed, ac¬
cording to the nature of the folution, and the evapo¬
ration, whether it has been more (lowly or more rapid¬
ly conduced. When this folution of mercury in nitric
acid is made in the cold, the compound formed is a
nitrate of mercury without excefs of the oxide or bafe j
but if mercury be added to this folution, and the ac¬
tion be aided by heat, a new portion of the oxide is
diffolved. It is then a nitrate of mercury with excefs
of bafe. Fourcroy diftinguilhes three nitrates of mer¬
cury. I. Nitrate of mercury neutralized. From this
regular cryftals are obtained, and it is not precipitated
by water. 2. The acidulous nitrate of mercury, or
with excefs of acid. This is obtained by diffolving
the firft in water containing nitric acid, or by adding
this acid to the other nitrates. 3. The nitrate of
mercury with excefs of oxide. This exifts in the fo¬
lution precipitated by water, or by expofing the other
nitrates to the aftion of heat. In this way is produ¬
ced what w?as formerly called nitrous turpeth.
2. Thefe different nitrates of mercury poffefs many
common properties, but are fufficiently diftinguithed
by others, and particularly by their decompolition.
When the nitrate of mercury is placed upon burning
coals, it detonates feebly, although with a vivid white
flame, when it has been fufficiently dried ; but when
it is moift it melts, blackens, extinguithes that part of
the coal which it touches, and throws out fmall red
fparks, with a flight decrepitation about the dried
edges of the mafs. The nitrate of mercury with ex¬
cels of oxide poffeffes a (fill more feeble detonating
property. The nitrate of mercury with excefs of acid
boils up, melts very rapidly, fwells greatly, and ex¬
hales red vapours, with very little detonation. If the
nitrate of mercury, neutralized, be heated in a cruci¬
ble without any combuftible matter, it melts, exhales
nitrous gas, becomes of a deep yellow colour, then
paffes to an orange, and at laft is converted into a
deep red. In this (late it was formerly called red pre¬
cipitate. It is the red oxide of mercury, which is ob¬
tained by the decompofition of the nitrate.
3. The pure nitrate of mercury expofed to the air in
I S T R Y. 645
the ftate of cryftals, is foon changed. It gradually Mercury,
abforbs oxygen from the atmofphere, and paffes from &c-
a white to a yellow colour. This is the nitrous tur-
peth. It is a yellow oxide of mercury combined with
a fmall portion of nitric acid, or a nitrate of mercury
with excefs of bafe. The yellow colour becomes
.deeper with the addition of boiling water. The ni¬
trous turpeth, it has been obferved, contains a greater
quantity of oxygen than that which is prepared by
fulphuric acid, and from this circumftance it is more
readily converted into red oxide by the a&ion of
heat. ryr?
4. The nitrate of mercury is decompofed by all the Decompofl-
alkalies, but with different phenomena, according to1*011'
the ftate of the combination, and particularly the de¬
gree of oxidation o( the bafe. Bergman has diftin-
guiflied the twm folutions of mercury, that which is
not precipitated by water, from that which is precipi¬
tated by the different produfts which are obtained
by means of alkalies. The nitrate of mercury affords,
with potafti, a yellowiftr white oxide ; with carbonate
of potafti, a white oxide j and with ammonia, an oxide
of a dark gray colour. Sulphuric acid and the ful-
phates occafion a precipitate in form of a white powT-
der. Muriatic acid and the muriates give a thick
mafs refembling curd. But the folution which is
precipitated by water, and which is more acrid, and
lefs difpofed to cryftallize, affords precipitates by
means of the fixed alkalies, of a deeper yellow or brown
colour. By means of ammonia, a white precipitate is.
formed. By means of the fulphuric acid and the fi.il-
phates, a yellow precipitate, and by the muriatic acid,
a more copious, curdled matter. Fourcroy has ob¬
ferved in the decompofition of nitrate of mercury
with excefs of acid, that a precipitate in the ftate-
of black powder is formed, with a great addition of
the alkali; but if it be added in fmall quantity, tho
precipitate is white or gray. A copious precipitate is
obtained, from the clear fupernatant folution, by di¬
luting it with water. The lame white precipitate is
obtained, by mixing together nitrate of mercury and
nitrite of ammonia. By evaporating the liquid, which
is rendered turbid by the addition of water, fix-fided
prifmatic cryftals are depofited, as the ammonia is vo¬
latilized. The w’hite precipitate is a brittle fait,
which has very little folubility, having an excefs of
oxide, of mercury, and ammonia. The component Compoli-
parts of this fait, according to Fourcroy are, tion.
Acid and water 15.80
Oxide of mercury 68.20
Ammonia 16.00
IOO.OO'
1731
5. From a folution of mercury in nitric acid,. Mr Howard’s
Howard prepared a fulminating pow'der poffeffed offaltninat-
peculiar properties ; the procefs which he found to an-inSP8w^er*
fwer beft, is the following :
“ One hundred grains,or a greater proportional quan-piepara-
tity, ofquickfilver (not exceeding 500 grains) are to be tion.
diffolved, with heat, in a meafured ounce and a half of
nitric acid. This folution being poured cold upon two
meafured ounces of alcohol, previoufly introduced into
any convenient glafs veffel, a moderate heat is to be
applied until an effervefcence is excited. A white
fume :
646
CHEMISTRY.
Mercury,
&c.
1733
Properties.
1734
Decompoh
ition.
1735
Compofi-
tion.
fume then begins to undulate on the furface of the li¬
quor ■, and the powder will be gradually precipitated,
uuon the ceffation of action and re-aftion. The preci¬
pitate is to be immediately collefted on a filter, well
waffled with diftilled water, and carefully dried in a
heat not much exceeding that of a tvater bath. The
immediate edulcoration of the powder is material, be-,
caufe it is liable to the re-adlion of the nitric acid j
and, whilft any of that acid adheres to it, it is very
fubjeft to the influence of light. Let it allb be cau-
tioufly remembered, that the mercurial folution is to be
poured upon the alcohol.
“ I have recommended quickfilver to be ufed in pre¬
ference to an oxide, becaufe it feems to anfwer equally,
and is lefs expenfive $ otherwife, not only the pure red
oxide, but the red nitrous oxide and turpeth may be
fubftituted ; neither does it feem effential to attend to
the precife fpecific gravity of the acid or the alcohol.
The reflified fpirit of wine and the nitrous acid of
commerce never failed, with me, to produce a fulmi¬
nating mercury. It is indeed true, that the powder
prepared without attention, is produced in different
quantities, varies in colour, and probably in ftrength.
From analogy, I am difpofed to think the whiteft is the
Itrongeft ) for it is well known, that black precipitates
of mercury approach the neareil to the metallic ftate.
The variation in quantity is remarkable ; the fmalleft
quantity I ever obtained from 100 grains of quickfilver
being 120 grains, and the largeft 132 grains. Much
depends on very minute circumffances. The greateft
produft feems to be obtained, when a veffel is ufed
which condenfes and caufes moft ether to return into
the mother liquor ; befides which, care is to be had in
applying the requifite heat, that a fpeedy and not a
violent aftion be effefted. One hundred grains of an
oxide are not fo productive as 100 grains of quick¬
filver.
This powder, ftruck on an anvil with a hammer, ex¬
plodes with a ftunning difagreeable nolle, and with
fuch force, as to indent both the hammer and the
anvil. Half a grain or a grain, if quite dry, is as
much as ought to be ufed on fuch an occafion. The
fhock of an eledtric battery, fent through five or fix
- grains, produces a very fimilar effect. The powder
explodes at the 368th degree of Fahrenheit’s thermo¬
meter. A quantity of it, fufficient to difcharge a bul¬
let from a gun, with a greater force than an ordinary
charge of gunpowder, always burfts the piece. Ten
grains of the powder, exploded in a glafs globe, pro-'
duce only four cubic inches of air, confifting of carbo¬
nic acid gas and nitrogene, or azotic gas.
This powder is decompofed by fulphuric, nitric,
and muriatic acids. When concentrated fulphuric
acid is poured upon it, an immediate explofion takes
place. According to the experiments of Mr Howard,
this powder confifts of oxalate of mercury, and nitrous
etherifed gas. But it appears that the nature of the
component parts varies with the different modes which
are followed in its preparation. When it is prepared
with little heat, it confifts of nitric acid, oxide of mer¬
cury, and a peculiar vegetable fubftance ; but by con¬
tinuing the heat during the fermentation, a greenilh
colour is communicated to the powder. It is then
found to be compofed of ammonia, oxide of mercurv,
and a greater proportion of the vegetable matter. Its
detonating pow’er is more feeble, and it gives out a blue Mercuryi
flame when placed on hot coals. By boiling the mix- ^
tore for half an hour, it is compofed ol oxalate of mer¬
cury, and a fmall proportion of vegetable matter j does * PHI-
not detonate, but decrepitates when it is heated. * Tranf.
4. Muriate of Mercury.
iSoc,
1735
1. Muriatic acid has no action whatever on mer-This com-
cury j but it combines readily with its oxides, and Pound tong
forms falts wdrich have been the fubjeft of refearch*cnGwn’
among chemills, almoft in every age. The muriates
of mercury wTere known to the Arabians in the 10th
and nth centuries. They were the firft objefts of
ftudy and examination with the alchemifts, in their
fearch after the philofophers ftonc } and fince chemiftry
affumed the form of a fcience, they have greatly oc-,
cupied the attention of philoibphers, in difcovering
their nature and properties. 17^7
2. There are two compounds of muriatic acid and jwo n!uri„
the oxides of mercury, which poffefs very different ates.
properties, according to the degree of oxidation of the
mercury. _ _ _ i738
3. Muriatic acid precipitates the oxides of mercury Prepara-
from their folutions in fulphuric and nitric acids. IH'011*
muriatic acid be added to the yellow fulphate of mer¬
cury, or to the nitrate of mercury which is precipi-
table by water, a muriate of mercury is obtained,
which is foluble in water, and which, on account of
its properties, w'as formerly called corrofive fublimate^ /
or corrojive muriate of mercury. But if muriatic acid
be added to the acidulous fulphate of mercury, or to
the nitrate of mercury which affords no precipitate
wdth water, a white, infoluble, infipid precipitate is
obtained, which was formerly called fvoeet mercury or
calomel, and is now' known by the name of fubmuriate,
and fometimesyw?^/ muriate of mercury.
4. The muriate of mercury, or corroftve fublimate, of the
may be prepared by the following procefs. Boil two muriate.-
parts of mercury with twTo and a half of fulphuric acid
in a matrafs, with the heat of a fand bath, to drynefs.
Let this dry mafs be mixed with four parts of dried
muriate-of foda, and let the whole be fublimed in a
glafs veffel, by gradually increafing the heat. In the
firft part of this procefs, part of the fulphuric acid is
decompofed •, the mercury combines with the oxygen
and forms an oxide, w'hich is diffolved in the unde-
compofed part of the fulphuric acid, and a fulphate of
mercury is thus obtained. The muriate of foda being
mixed with this fait, produces another decompofition.
The muriatic acid combines with the mercury, form¬
ing the muriate of mercury, which is fublimed ; and
the fulphuric acid of the fulphate of mercury combines
with the foda, forming a fulphate of foda, which re¬
mains behind. I740
5. The muriate of mercury thus obtained, forms a Properties,
beautiful white, femitranfparent mafs, which is found
to be compofed of fmall prifmatic cryftals in the form
' of needles. It may be obtained by evaporation, in the
form of cubes or rhomboidal prifms, or four fided
prifms, having the alternate Tides narrower, and termi¬
nated by twTo-fided fummits. The tafte is extremely
acrid andcauftic, and the metallic imprefilon remains long
on the tongue. The fpecific gravity is 5.1398. It is
foluble in 20 parts of cold water, and in lefs weight
of boiling water. This fait is not altered by expolure
to
CHEMISTRY.
Mercury,
See.
1741
Gompoli-
tion
3 743
Cempoli-
tion.
to the air j and, when it isfublimed by heat, it remains
unchanged. It is foluble in fulphuric, nitric, and muri-
atic acids, and, when thefe folutions are evaporated, the
muriate of mercury is obtained unaltered. It is preci¬
pitated by all the alkalies and earths, of an orange-
yellow colour, which gradually changes to a brick-
red. The carbonates of the fixed alkalies afford a per¬
manent yellow colour. Ammonia forms with it a tri¬
ple fait. The component parts of this fait, according
to Mr Chenevix, are,
Oxide of mercury 82
Acid 18
174*
Prepara¬
tion.
IOO
Muriate of mercury is one of the moft violent poifons
known. When taken internally, it produces naufea
and vomiting, with fevere pain, and, in a fhort time,
corrodes the fiomach and bowels. Externally, it is
employed as an efcharotic for deftroying fungous flelh.
It fublimes readily when heated, and is extremely in¬
jurious in the date of vapour, to thofe who breathe
it.
Submuriate of Mercury.—This fait is prepared by
triturating together in a glafs mortar, four parts of
muriate of mercury or corrofive fublimate, with three
of mercury, till the latter difappear. When this is
formed into an uniform mafs, it is put into a matrafs,
of which it fliould fill and it is to be fublimed with
the heat of a fand bath. When the procefs is finifhed,
the phial is broken ; and the white matter at the upper
part of the veffel, and the red matter at the bottom,
are to be feparated, and the remaining part of the mafs
is to be fublimed, and afterwards reduced to a fine pow¬
der, which is to be well wafhed with boiling water.
In this procefs, it is obvious, that the mercury which
is added, combines with part of the oxygen of the
oxide of mercury, formerly combined with the muria¬
tic acid; and the whole of the oxide of mercury having
now a fmaller proportion of oxygen, is combined with
a fmaller proportion of muriatic acid. This wall ap¬
pear from the proportions of its component parts, as
they have been afeertained by Mr Chenevix.
Oxide of mercury in calomel contains,
Mercury 89.3
Oxygen 10.7
100.0
Calomel is compofed of
Oxide of mercury 88.5
Muriatic acid 11.5
100.0
*744
Properties.
&.C.
647
tion than the muriate of mercury. It is converted in- Mercury,
to the muriate or corrofive fublimate, by the nitric and (
oxymuriatic acids.
This fait, which is now generally known in the Difrerent
fhops, by the name of calomel or fweet mercury, was names,
formerly deferibed under a great variety of names, de¬
rived from its effefls, or the mode of its preparation.
In the beginning of the 17th century, it was regarded
as an important fecret. But, in the year 1608, Be-
guin deferibed it very accurately, in his tyrocinium che-
rnicum, under the name of the dragon tamed, on ac¬
count of the corrofive fublimate from which it wras
prepared, being deprived of its poifonous and deftruc-
tive qualities. At different periods it was diftinguifhed
by other names, as aquila a/ba, aqui/a mitigata, manna
metaflorum, panebymagogus quercitanus, &c. The ufe
of this fait as a purgative, and indeed in all cafes
W'here mercurial preparations are required, is well
known.
5. Muriate of Ammonia and Mercury. 1740
If ammonia be added to a folution of muriate
mercury, or corrofive fublimate, a white precipitate is
obtained, which is a triple fait, formed by the combi¬
nation of the ammonia with the muriate of mercury.
This white precipitate has at firft an earthy tafte,
which becomes afterwards metallic and difagreeable*
It feems to be infoluble in water. Sulphuric acid
forms with this triple fait, corrofive fublimate, and ful-
phate of ammonia and mercury. Nitric acid converts
it into corrofive fublimate and nitrate of ammonia and
mercury. It is completely foluble in muriatic acid,
and there is formed a muriate of mercury and ammonia.
This preparation was known to the alchemiils, and
dillinguilhed by the names of fal alembroth, and fait of
xvifdom. The component parts of this lalt, accbrding
to Fourcroy, are
Acid, 16
Oxide of mercury, 81
Ammonia, 3
Submuriate of mercury, or calomel, is generally in
the form of a white, folid mafs ; but it is fufceptible of
cryftallization in four-fided prifms, terminated by pyra¬
mids. It has fcarcely any tafte, has no poifonous pro¬
perty, and is very little foluble in water. The fpeci-
fic gravity is 7.1758. It becomes dark coloured by
expofure to light, is phofphorefcent when rubbed in the
dark, and requires a higher temperature for its fublima-
6. Hyperoxymuriate of Mercury.
This fait was formed by Mr Chenevix, by pafling a
current of oxymuriatic acid gas through w-ater, in
which there was red oxide of mercury. 'I he oxide
became of a dark brown colour, and a folution appear¬
ed to have taken place. The liquor was evaporated
to drynefs, and a fait was obtained which confifted
partly of corrofive fublimate, and partly of hyperoxy¬
muriate of mercury. By feparating the latter, and
cryftallizing it again, it was obtained nearly pure.
This fait is more foluble than corrofive fublimate, four
parts of water retaining it in folution. Hyperoxymuri¬
atic acid is given out by the addition of fulphuric, or
even weaker acids, and the liquid aflumes an orange
colour f.
7. Fluate of Mercury.
Fluoric acid combines only with the oxide of mer¬
cury 5 or the foluble fluates mixed with a folution of
nitrate’of mercury, produce a precipitate of a white
colour, which is the fluate of mercury, of which the
properties are little known. -
* Fourcryj
v. 309—
34*-
1747
Prepara¬
tion.
I74S
Properties.-
f Phil.
‘TtanJ.
1802.
p. 260.
8. Boratq
'648
Mercury,
&c.
G H E M I
8. Borate of Mercury.
Boracic acid has no direct aftion on mercury, but
by mixing together a folution of the borate of foda
with a folution of nitrate of mercury, a yellowifh preci¬
pitate is obtained, which is the borate of mercury.
This fait acquires a greenifh colour by expofure to the
air. Lime water forms a precipitate of a red powder.
9. Phofphate of Mercury.
Phofphoric acid has no adtion on mercury, but it com¬
bines with its oxide. This fait may be prepared by
precipitating the nitrate of mercury in folution, by
means of phofphate of foda. A white precipitate is
formed, which is phofphate of mercury. This fait is
infoluble in water, phofphorefces when rubbed in the
dark, and is decompofed by heat, giving out phofpho-
■* . rus.
10. Carbonate of Mercury.
By precipitating the folutions of mercury on the
other acids by means of the alkaline carbonates, a
white precipitate is obtained, which is a carbonate of
mercury.
j 1. Arfeniate of Mercury.
When arfenic acid is diftilled in a retort with mer¬
cury, it is partially decompofed. Arfenious acid is
fublimed, with a portion of metallic mercury and a
fmall quantity of yellow oxide. There remains be¬
hind a yellow mafs, which is arfeniate of mercury. It
is infoluble in water, and in fulphuric and nitric acids.
It is foluble in muriatic acid, and affords by evapora¬
tion and fublimation, the muriate of mercury, or cor-
rofive fublimate. Arfenic acid precipitates the fulphate
and nitrate of mercury in the form of a white powder,
which is alfo arfeniate of mercury.
12. Tungftate of Mercury.
This fait is formed by adding to a folution of nitrate
of mercury, an alkaline tungftate. The fait is decom¬
pofed, and the tungftate of mercury is precipitated in
the form of a wdiite infoluble powder.
13. Molybdate of Mercury.
Molybdic acid precipitates mercury from its folution
in nitric acid, in the form of a white flaky powder. It
is alfo infoluble in water.
14. Chromate of Mercury.
An alkaline chromate in folution, added to a folu¬
tion of nitrate of merqury, forms a precipitate of a
fine reddifti purple colour. This is the chromate of
mercury, which is infoluble in water, and which Vau-
quelin, wdro difcovered it, luggefts to be employed as
a pigment.
v 1 15* Columbate of Mercury.
Unknown.
i 6. Acetate of Mercury.
1749 I. Acetic acid combines with the oxides of mercu-
“ and forms different &ltsp according to the oxide
p*4es. 2
S T R Y.
which enters into the combination. With the red ox- Mercury,
ide of mercury it forms a fait which does not cryftal-, ^
lize ; but when the liquid is concentrated, and evapo- k
rated to drynefs, it affords a yellow deliquefcent mafs.
When this fait is diffolved in water, it divides into
twro parts ; the one falls down in the ftate of yellow
powder, which is the acetate of mercury with excefs
of bafe *, and the other part remains in folution, be-
caufe it contains an excefs of acid.
2. But when the nitrate of mercury is precipitated
by means of alkalies, and the precipitate is diffolved
in acetic acid, the folution yields by evaporation and
cooling, acetate of mercury, in thin brilliant flakes.
This fait may alfo be formed by mixing together folu¬
tions of acetate of potaflr and nitrate of mercury.
The acetate of mercury appears in the form of large
flat cryftals, which have an acrid tafte, and are fcarce-
ly foluble in water. This latter fait is a compound of
acetic acid and the oxide of mercury, with a fmaller
proportion of oxygen. It is employed in rfiedicine,
and forms the principal ingredient of Keyfer's pills.
17. Oxalate of Mercury.
Oxalic acid combines with the oxide of mercury,
and forms an oxalate in the ftate of white pow'der,
which is fcarcely foluble in water. It becomes black
by expofure to the light. When it is heated it detonates.
This fait may alfo be obtained, by adding oxalic
acid to a folution of the nitrate or fulphate of mer¬
cury.
18. Tartrate of Mercury.
Tartaric acid forms an infoluble fait of a white co¬
lour, with the oxide of mercury, wdiich becomes yel¬
low by expofure to the light.
19. Tartrate of Potafh and Mercury.
This triple fait may be prepared by boiling together
in water, one part of oxide of mercury, and fix of tar¬
tar. Cryftals of the triple fait are obtained by evapo¬
rating the liquid.
20. Citrate of Mercury.
Citric acid produces an effervefcence with the red
oxide of mercury, changes into a white colour, and
then unites it in one mafs. This fait is fcarcely folu¬
ble in water. It has a metallic tafte, and is decompo¬
fed by nitric acid.
21. Malate of Mercury.
When malic acid is added to a folution of nitrate of
mercury, a white precipitate is formed, which is ma¬
late of mercury.
22. Benzoate of Mercury.
Benzoic acid forms with the oxide of mercury, a
fait in the ftate of w'hite powder, which is infoluble in
water, and is fcarcely altered by expofure to the air.
It is decompofed by heat.
23. Succinate of Mercury.
Succinic acid combines with the oxide of mercury
with the afliftance of heat, and forms with it an irre¬
gular mafs in which fome cryftals are obferved.
24. Sa.ccolate
C H E M I
^ i 24. Saccolate of Mercury.
By adding faclaftic acid to a folution of nitrate of
mercury, a white precipitate is formed, which is fac-
colate of mercury.
25. Mellate of Mercury.
Mellitic acid added to a folution of nitrate of mer¬
cury, produces a copious precipitate, which is re-dif-
* Klaproth folved by the addition of nitric acid *.
EJfays, II.
loa. T'ranjl. 26. Pruffiate of Mercury.
This fait is obtained by boiling the red oxide of
mercury with Pruflian blue. It forms cryftals in four-
fided prifms, terminated by four-fided pyramids. The
fpecific. gravity is 2.7612. It. forms triple falts with
fulphuric and muriatic acids, the properties of which
are not known.
II. Adlion of Alkalies, &c.
There is no adlion between mercury and the alkalies
or alkaline earths $ but the alkalies combine with the
oxides of mercury, and form with them compounds in
which the latter feem to aft the part of acids. Some
of thefe compounds have been already treated of, in
fpeaking of the aftion of ammonia on fome of the mer¬
curial falts.
Salts formed with the alkalies and earths, have no
aftion on mercury or its oxides, if we except the mu¬
riates. By diffolving the muriate of mercury in a fo¬
lution of muriate of ammonia, a triple fait, which is
muriate of ammonia and mercury, and which has been
already defcribed, is obtained.
Ufes. Mercury is one of the metals of the moll extenfive
utility. In the metallic ftate it is applied to the con-
ftruftion of meteorological inftruments, as the baro¬
meter and thermometer. Mercury is alfo applied to a
great variety of purpofes in the arts ; in gilding with
filver and gold ; in forming an amalgam with tin for
covering the back of mirrors ; and in metallurgy for
the purpofe of feparating gold and filver from their
ores. Mercury is alfo of conliderable importance for
the purpofes of chemiftry. Many of its preparations
form fome of the molt effeftual and molt certain reme¬
dies in different difeafes.
Sect. XV. Of Zinc and its Combinations.
Hiltory! 1 • Paracelfus is the firft who fpeaks of zinc under
its prefent name. It is fuppofed that the Greeks were
acquainted with this metal in the ftate of compound
with copper, which formed the famous Corinthian
brafs 5 but it does not appear that they made any di-
ftinftion between it and other metals. It is particu¬
larly mentioned by Albertus Magnus, who died in
1280, and he feems to have known that it inflamed,
and communicated a colour to metals with which it
was combined. The method of obtaining zinc from
the ore called calatnine, is mentioned by Henckel in his
pyrotology in 1721. Swab extrafted it by diftillation
in 1742, and Margraaf was occupied with this procefs
in 1746. Zinc was fuppofed by the earlier chemifts
to be a variety or compound of fome of the other me¬
tals. Lemery thought it was a kind of bifmuth, and
Vol. V. Part It
S T R Y. 649
Homberg took it for a mixture of iron and tin j while Zincy&c*
others fuppofed that it was tin rendered brittle by ful- * v—
phur, or that it was a coagulated mercury. 1752
2. Zinc is found in four different ftates; In the ftate Oses.
of oxide, in the ftate of fulphuret, in that of fulphate,
and in that of carbonate. 1. In the ftate of oxide it is
known by the name of calamine^ or lapis ca/atninans} de-
pofited in a regular form, or in that of incruftations and
ftalaftites, in the cavities of metallic veins. 2. The ful¬
phuret of zinc, known by the name of blende, is fome-
times difpofed in fcales, and fometimes cryftallized in
tetrahedrons, or oftahedrons. It is frequently found in
lead mines, accompanying the ores of lead. 3. The ful¬
phate of zinc, which is found native, is readily
known by its white colour and tranfparency, its ftrong
acrid tafte, and folubility in water. It is generally
found in a ftalaftitical form, or in fine filky cryftals,
like thofe of amianthus. 4. The native carbonate of
zinc, which is fometimes confounded with the oxide
or calamine, forms another ore of zinc. It is tranfpar-
ent, white, or yellowifli. It is infipid and infoluble
in water, and diffolves with effervefcence in nitric and
muriatic acids. i
3* To reduce oxides of zinc to the metallic ftate, the Analyfas.
ore is pulverized and mixed with charcoal, and the mix¬
ture is heated in a crucible covered with a plate of cop¬
per. . The zinc is fublimed in the metallic ftate, and
combines with the copper, which it converts into brafs;
and in this rude procefs the richnefs of the ore is af-
certained by the intenfity of the colour. The fulphu-
rets of zinc are reduced by roafting, by which procefs
the fulphur is feparated, and the reiiduum is then
treated in the fame way as the oxides. In the humid
way Bergman has propofed to analyze the oxides of
zinc by means of fulphuric acid, and then by precipi¬
tating the oxide by carbonate of foda, he has afcertain-
ed that 193 parts of this precipitate give too parts of
the metal.
4. Zinc is of a brilliant w'hite colour with a bluifh ProPerftes.
fhade, which is very perceptible in its metallic ftate,
and of a diftinft lamellated texture ; but the plates of
which it is compofed are fmaller than thofe of bifmuth
and antimony. The fpecific gravity is 7.190. Zinc
is not quite fo brittle as the preceding metals. It re¬
quires a fmart and hidden blow to feparate its fracr.
ments. It is fufceptible of a flight degree of malleabi¬
lity, for^by gradual and cautious preffure, it may be
formed into thin plates, which have fome degree of
elafticity. It has^ a flight odour, and a peculiar tafte,
which is communicated to the fingers when they are*
rubbed on this metal.
5. When zinc is expofed to a heat of about 700° it Aftion of
melts, and by increafing the heat it evaporates, fo that heat.
in clofe veffels it may be diftilled. When allowed to
cool flowly after being in fufion, it cryftallizes in fine
needles. When zinc is expofed to the air, it under¬
goes very little alteration in the cold. Its brilliancy
is flightly tarniftied, and it becomes at length covered 1756
with a thin gray oxide. When zinc is fufed in clofe Oxidation,
veffels and expofed to heated air, at the moment it be¬
comes folid on the furface, it exhibits a great variety
of flrades of colour, which is the commencement of oxi¬
dation. When it is kept in fufion, in the open air,
the furface becomes covered with a gray pellicle, which
being removed, is fucceeded by another, till the whole
4 N 0f
1757
Oxides
two.
1.753
Adtion of
hydrogen.
*759
Of carbone
1760
Phofphuret
17 61
Phofphora-
ted oxide.
175a
Sulphuret.
of the zinc is converted into this gray-coloured matter,
which is an oxide of zinc. This procefs may be pro¬
moted by agitating the veiTel, fo that the metal in fu-
lion may be expofed to the air. By heating together
the gray pellicles which have been collefted in an open
veffel, the whole is converted into a uniform gray pow¬
der, which at laft affumes a yellowith colour. The
yellow oxide, thus formed, has acquired an additional
weight of about 17 per cent of the metallic zinc.
When this metal is heated to rednefs in an open
veffel, by agitating the veffel, it fuddenly takes fire,
and burns with a very brilliant white, and fomewhat
greenilh flame. Zinc is at the fame time reduced to a
flate of vapour, which is condenfed in the air, in light,
filamentous, white flakes, of a very delicate texture.
This is an oxide of zinc. It has been diflinguifhed
by different names, as flowers of •zinc, nihil album or
while nothing, lanaphilofophica, or philoflophic wool.
Thus, there are two oxides of zinc •, the gray oxide,
which confifts of about 88 parts of zinc, and 12 of
oxygen, and the white oxide, which, according to
Prouft, is compofed of 80 parts of zinc, and 20 of
oxygen.
There is no aflion between azote and this metal.
Hydrogen gas, it is fuppofed, diffolves a fmall quantity
of zinc} for by diffolving zinc in diluted fulphuric acid,
the hydrogen gas which is obtained by the decompofi-
tion of the water, has been found to hold a little zinc
in folution, which is depofited on the fides of the jars
.containing the gas. It is fuppofed too, that zinc is
fometimes combined with carbone, becaufe hydrogen
gas obtained by the above procefs, is fometimes conta¬
minated with carbonated hydrogen gas.
7. Zinc combines with phofphorus, and forms a phof¬
phuret. This may be prepared by adding fmall bits
of phofphorus to zinc in fufion, but previoufly throwing
in a little refinous matter, to prevent the oxidation of
the zinc. This was the procefs by which Pelletier
formed the phofphuret of zinc. This phofphuret is
of a white colour and metallic luftre. It has fome de¬
gree of malleability. When it is hammered, it emits
the odour of phofphorus, and when expofed to a ftrong
heat, it burns like zinc. Phofphorus alfo enters into
combination wdth the oxide of zinc, and forms with it
a phofphorated oxide. This is formed by diftilling in
an earthen-wmre retort, equal parts of oxide of zinc, and
phofphoric glafs, with one-fixth of charcoal pow’der.
A rtrong heat is applied, and a metallic fubftance of a
filvery white colour is fublimed, which has a vitreous
fra&ure. When it is heated by the blow-pipe, the
phofphorus burns, and there remains behind a vitreous
matter, which is tranfparent while in fufion, but be¬
comes opaque when it is cold.
8. Zinc has not been combined direftly with ful-
phur. When they are heated together in a crucible,
the fulphur feparates without producing any other
change on the zinc than that of being a little more in-
fufible ; but it has been obferved that fulphur and zinc,
when fufed together in a crucible, enter into combina¬
tion, as the zinc is oxidated. This compound affumes
a brownifh gray colour. Guyton afterwards difeover-
ed that fulphur and the oxide of zinc readily unite to¬
gether by fufion, and that the compound is of a gray
colour, fimilar to the native fulphuret of zinc, as it has
been called, or the fulphurated oxide of zinc, accord-
CHEMISTRY.
ing to this experiment} but according to Prouft, the Zinc, See.
ore of zinc, which is known by the name of blende, is a r“““
fulphuret, that is, fulphur combined wdth zinc in the
metallic ftate. _ 1763
9. The order of the affinities of zinc and its oxide is Affinities,
the following :
Zinc.
Copper,
Antimony,
Tin,
Mercury,
Silver,
Gold,
Cobalt,
Arfenic,
Platina,
Bifmuth,
Lead,
Nickel,
Iron.
Oxide of Zinc.
Oxalic acid,
Sulphuric,
Muriatic,
Sacla&ic,
Nitric,
Tartaric,
Phofphoric,
Citric,
Succinic,
Fluoric,
Arfenic,
La£tic,
Acetic,
Boracic,
Pruffic,
Carbonic.
I. Salts of Zinc.
1. Sulphate of Zinc.
t7<r4
r. Sulphuric acid diluted with wrater, a£ls very Prepara-
pow'erfully on zinc. A violent effervefcence takes b011*
place 5 the mixture is ftrongly heated, and a great
quantity of hydrogen gas is evolved. In this procefs,
which is ufually followed for obtaining the pureft hy¬
drogen gas for chemical purpofes, the water is decom-
pofed } its oxygen combines with the metal and forms
an oxide, which is then diffblved in the fulphuric acid,
and forms a fulphate of zinc, while the hydrogen, the
other component part of the water, efcapes in the
form of gas. A black pow’der is fometimes obferved
floating in the folution, which is carburet of iron,
with which the zinc is frequently contaminated. As
the effervefcence ceafes, a white powder is formed,
which gradually difappears towards the end of the
procefs, and with the addition of water forms a tranf¬
parent folution. By evaporation and cooling, the ful¬
phate of zinc is obtained cryftallized. *765
2. The fulphate of zinc is frequently contaminated Properties^
with other metals, as with lead, iron and copper }
but when it is pure, it cryftallizes in four-fided prifms,
terminated by pyramids with four faces. This fait
has an acrid, aftringent, and ftrongly metallic tafte.
When it is expofed to the air it efflorefees. It is
foluble in lefs than two and a half parts of cold wa¬
ter, and more foluble in boiling water. The {pacific
gravity of the cryftallized fait is 1.912} but as it is
generally met with in the (hops, it is only 1.3275.
When heated in a retort, it melts, lofes its water of
eryftallization, and part of its acid in the ftate of ful-
phurous acid, and a little water. It is decompofed
and precipitated in the ftate of white oxide by all the
alkalies ; and if the precipitate is formed by means of
the carbonates, a white pigment is obtained. The
fulphate of zinc is alfo decompofed with the affiftance
of heat, by means of nitre. The alkaline fulphurets
and hydrofulphurets alfo precipitate the fulphate of
C H E M
Zinc,&c. zinc, of a deep orange or brown colour. The com¬
ponent parts of this fait are, according to
1765
Compofi-
tion.
Acid,
Oxide,
Water,
Bergman.
40
20
4®
Kirwan.
100
100.0
"White vi¬
triol.
!7<j8
Prepara¬
tion.
1759
Properties.
1770
Combines
with ful-
phur.
1771
Properties.
3. The fait, known in commerce by the name of
’white vitriol, is a fulphate of zinc, and is fuppofed to
contain an excefs of acid. It is in the form of white
granular maffes, refembling fugar, and often marked
wTith yellow fpots. This fait is ufually prepared by
roafting the fulphuret of zinc, or blende, by which
means the fulphur is converted into fulphuric acid. It
is then diflblved in water, which is purified and evapo¬
rated, and the fait is cryftallized by hidden cooling.
Part of its water of cryftallization is afterwards driven
off by heat, fo that it is obtained in a regular, folid,
and granulated mafs. It is generally contaminated
with iron and other metals ; but it may be purified
from thefe, by adding filings of zinc, which preci¬
pitate the other metals, and leave a pure fulphate of
zinc.
2. Sulphite of Zinc.
Concentrated fulphurous acid readily combines W'ith
the white oxide of zinc, without any effervefcence,
but with the evolution of heat, and the acid being de¬
prived of its odour. When the faturation is complet¬
ed, white cryftals appear on the furface of the liquid.
This fait has a pungent, aftringent tafte. It cryftal-
lizes readily. It is decompofed by the acids, with
effervefcence. It is infoluble in alcohol. It forms
white precipitates wnth the alkalies, and when expofed
to the air, it is readily converted into fulphate of
zinc.
Sulphurated fulphite of Zinc.—When fulphurous acid
is added to zinc in the ftate of powder or filings, a
great degree of heat is produced j fulphurated hydro¬
gen gas is difengaged j the liquid becomes at firft
brown, fometimes muddy, and affumes a yellow co¬
lour, and towards the end of the procefs it becomes
tranfparent. The folution has an acrid, aftringent,
and fulphureous tafte. Sulphuric and muriatic acids
difengage with effervefcence, fulphurous acid gas, and
precipitate a yellowifh-white powder. Nitric acid at
firft feparates fulphurous acid gas, and afterwards a
flaky precipitate, which is pure fulphur. When this
folution is expofed to the air, it becomes thick like ho¬
ney, and affords cryftals in the form of needles or fine
four-fided prifms, terminated by four-fided pyrimids.
Thefe are cryftals of fulphurated fulphite of zinc,
which become white by expofure to the air, and form
a white powder infoluble in water. When this fait
is heated by the blow-pipe, it fwells up, gives out a
bright light like burning zinc, and forms dendritical
ramifications. This fait is partly foluble in alcohol.
The part not diffolved, only gives out fulphurous acid
gas by means of fulphuric acid, whilft the part which
is diffolved affords, befides fulphurous acid gas, a copi¬
ous precipitate of fulphur. When it is diftilled in a
1 s, T R Y.
65!
retort, it gives out water, fulphurous acid, fulphuric Zinc, &c.
acid, and fulphur fublimed. There remains behind1 iji
oxide of zinc, mixed with a little of the fulphate.
In the folution of zinc in liquid fulphurous acid, wa-Theory of
ter, and part of the fulphurous acid itfelf, are decom-tke proccfs.
pofed *, for fulphurated hydrogen gas is difengaged,
which is compofed of the hydrogen of the water and
part of the fulphur of the fulphurous acid. There is no
precipitation of fulphur during the folution, for it com¬
bines with the fulphite of zinc, as it is formed *, but this
is not completely faturated, fince alcohol diffolves only
the portion of fulphurated fulphite which it contains, and
feparates the fulphite *. * Fourcray,
. . _ v. P. 380.
3. Nitrate of Zinc.
... . . 1773
1. Concentrated nitric acid produces a violent a&ion Prepara-
with zinc, and fometimes even inflames it. To effe&d011"
this folution, with a moderate a£tion, the acid fhould
be diluted with water. Great heat is produced, with
violent effervefcence and the evolution of nitrous gas.
The acid is decompofed ; its oxygen combining with the
metal, forms an oxide, which combines with the acid
as it is formed.
2. This folution is of a greenifti-yellow colour, and Properties,
extremely cauftic. By evaporation it affords cryftals,
in the form of four-fided, compreffed, and ftriated
prifms, terminated by four-fided pyramids. The fpeci-
fic gravity is 2.096. This fait is deliquefcent in the
air. When it is heated on burning coals, it melts, and
detonates with a fmall red flame. When heated in a
crucible, it gives out red vapour, and affumes a deep
colour and gelatinous confiftence. When cooled in
this ftate, it retains its foftnefs for fome time. By con¬
tinuing the heat, it dries, gives out nitrous and oxygen
gaffes, and leaves behind a yellow oxide.
4. Muriate of Zinc.
Muriatic acid produces a rapid aflion on zinc. It Prepara-
is diffolved with effervefcence, and with the evolution tion.
of pure hydrogen gas. The folution of zinc in muria¬
tic acid is colourlefs j it does not cryftallize, but af¬
fumes the form of a tranfparent jelly. It affords by
diftillation a fmall quantity of fuming acid, and a folid
muriate of zinc, which is fufible with a moderate heat,
and was formerly known by the name of butter of zinc.
When this muriate of zinc is fublimed by heat, it be¬
comes of a fine white colour, compofing a mafs of cry¬
ftals in the form of fmall prifms. It is decompofed by 1776
fulphuric acid, and is precipitated by the alkalies. It Properties,
is foluble in water, attradls moifture from the atmo-
fphere, and is foon converted into a tranfparent jelly.
The fpecific gravity is 1-577.
5. Muriate of Ammonia and Zinc.
This triple fait is formed by boiling white oxide of
zinc in a folution of muriate, of ammonia. The oxide
of zinc is diffolved ; part of which is afterwards depo-
fited, when the folution cools, but what remains in the
folution is not precipitated by the alkalies or the alka¬
line carbonates.
6. Fluate of Zinc. *
Fluoric acid produces a violent a&ion with zinc J
there is confiderable effervefcence, with the evolution
4 N 2 of
6$2 CHE M I
Zinc,&c. of hydrogen gas. The metal is oxidated, and then
diffolves in the acid } but the properties of this fait are
little known.
7. Borate of Zinc.
Boracic acid combines with the oxide of zinc, by
adding the borate of potafli or foda to the folution of
zinc in nitric or muriatic acid. This fait is infoluble
in water.
8. Phofphate of Zinc.
1777
Prepara- Phofphoric acid diluted with water, a£ls upon zinc
non. eVolution of hydrogen gas, owing to the de-
compofition of water. A white powder is depofited,
•which is phofphate of zinc. By expofing phofphoric
glafs and zinc to a flrong heat, a phofphuret of zinc
is formed, by the decompolition of the acid.
9. Carbonate of Zinc.
1778
Prepara- Zinc reduced to a fine powder, and added to liquid
tion, carbonic acid, is oxidated and copioufly difiblved in
the acid, at the end of 24 hours. This folution, ex-
pofed to the air, is covered with a pellicle of car¬
bonate of zinc of different colours. The carbonate of
zinc is found native, and has been diftinguifhed by the
name of calamine, thus confounding it with the oxide
of zinc. Carbonate of zinc, according to the analyfis
of Bergman, is compofed of
S T R Y.
Zinc, See,
15. Acetate of Zinc,  
Acetic acid diffolves zinc, and the folution by eva- 1779
poration cryftallizes in the form of rhomboidal orPrePara-
hexagonal plates. This fait has a bitter metallict;on anc* „
tafte, is not altered by expofure to the air, and is fo-pl°pcr 1U'*
luble in water. It burns with a blue flame when
thrown on burning coals. When diftilled, it yields
w-ater, an inflammable liquid, and fome oil. At the
end of the procefs, when the fait is completely de-
compofed, the oxide of zinc is fublimed, which being
brought in contaft with a candle, burns with a fine
blue flame. The refiduum is in the ftate of pyropho-
rus, but it has little combuftibility.
16. Oxalate of Zinc.
Oxalic acid adls upon zinc with effervefcence, and
the evolution of hydrogen gas. Water is decompof-
ed, and as the zinc is oxidated, it combines with the
acid, forming an oxalate of zinc. It is in the ftate of
white powder, of an acrid tafte, and but little foluble
in water.
17. Tartrate of Zinc.
Tartaric acid combines with zinc with effervefcence,
and the evolution of hydrogen gas. The properties of
this fait have not been examined.
18. Citrate of Zinc.
Acid 28
Oxide 66
Water 6
100
10. Arfeniate of Zinc.
When arfenic acid is added to zinc, it produces an
effervefcence, wdth the evolution of hydrogen gas,
holding arfenic in folution. A black powder is de¬
pofited, which is metallic arfenic. In this procefs,
the zinc decompofes part of the water, and combines
with its oxygen, and at the fame time deprives the
arfenic acid of its oxygen, by which it is reduced to
the metallic ftate. The arfeniate of zinc may be ob¬
tained by adding a folution of an alkaline arfeniate
to a folution of the fulphate of zinc. A white pre¬
cipitate is formed, wdiich is the arfeniate of zinc. It
is infoluble in water.
Citric acid a£ls upon zinc with effervefcence and
the evolution of hydrogen gas. At the end of 24
hours the adlion ceafes, and the liquid depofits on the
fides of the veffel and on its furface, fmall, brilliant
cryftals in the form of plates, which are infoluble in
water. The citrate of zinc has an aftringent, metallic
tafte. It is compofed of equal parts of acid and of
oxide of zinc.
19. Malate of Zinc.
Malic acid diffolves zinc, and by evaporating the
folution, cryftals may be obtained.
20. Benzoate of Zinc.
Benzoic acid readily diffolves zing, and by eva¬
poration the folution affords needle-fhaped cryftals-
The benzoate of zinc is foluble in wrater and alcohol.
When it is expofed to heat, the acid is fublimed.
21. Succinate of Zinc.
11. Tungftate of Zinc.
12. Molybdate of Zinc.
Thefe falts may be formed by a fimilar procefs. A
white powder is obtained, which is infoluble in water.
13. Chromate of Zinc.
This fait is obtained by combining an alkaline chro¬
mate with a folution of zinc in nitric acid. A preci¬
pitate is formed of an orange red colour, which is chro¬
mate of zinc.
14. Columbate of Zinc.
Unknown.
Zinc is diffolved in fuccinic acid with effervefcence.
By evaporation the folution affords flender, foliated
cryftals.
22. Laftate of Zinc.
Zinc is foluble in ladlic acid with effervefcence, and
by evaporating the folution, the fait may be obtained
cryftallized.
II. Aflion of Alkalies, &c. on Zinc.
I. When zinc is immerfed in a folution of potalh-pixe^alka*
or foda, it is tarniftied, and becomes black, and when lies,
it is boiled in the folution, hydrogen gas is evolved.
The folution affumes a dirty-yellow colour, from which
an oxide of zinc may be precipitated by acids.
2. Ammonia
CHEMISTRY.
Tin, See.
1781
Ammonia.
178a
Sulphates.
Nitrates.
. I784
Muriates.
17SS
Phofphates,
&c.
1785
Ufes.
1787
lliftory.
2. Ammonia has a ftill more powerful attion on
zinc. Hydrogen gas is more copioufly evolved, and
the oxide which is formed is more abundantly diflblv-
ed in the liquid, and at the end of feme time a Confi-
derable quantity of white oxide is depofited. Thefe
alkaline folutions become turbid by expofure to the
air ; its oxygen and carbonic acid, afting at the fame
time, precipitate the oxide.
3. The alkaline and earthy fulphates are readily de-
compofed by zinc, with the afliftance of heat. It at-
tra£ls the oxygen of the fulphuric acid, and thus de-
compofing it, feparates the fulphur, which combines
with the bafes of the fulphates. Alum boiled in fo-
lution with zinc, is decompofed, and there is formed
a triple fait, which is fulphate of zinc and alumina.
4. The nitrates produce a vivid inflammation with
zinc at a red heat. The acid is decompofed, its oxy¬
gen combines with the metal, and by this rapid com¬
bination, a violent detonation is produced. The azo¬
tic gas is difengaged, and the zinc is fully oxidated.
Three parts of nitre well dried, and one of zinc in fine
powder, well mixed together and proje&ed into a red-
hot crucible, produce a very brilliant inflammation.
The burning matter is fometimes thrown out to a con-
fiderable diftance 3 fo that the experiment fhould be
made with caution. This compound is fometimes em¬
ployed in fire works.
5. Zinc has a confiderable a£tion on the muriates.
Triturated with the muriate of ammonia, the fait is
decompofed, and ammonia is difengaged. By diflill-
ing this fait with zinc, ammoniacal and hydrogen gafes
are obtained 3 the latter is obvioufly owing to the de-
compofition of the water contained in the fait, by
means of the zinc, which combines with the oxygen,
and then forms a muriate of zinc with the muriatic
acid.
6. The phofphates and borates combine by fufion
with the oxide of zinc, which communicates to the
glafs thus formed a greenifli-yellotv colour.
7. Zinc decompofes the greateft number of the me¬
tallic falts from their folutions, by its ftrong affinity
for oxygen. They are precipitated in the metallic
form, or in the ftate of oxide, but deprived of a por¬
tion of oxygen.
8. Zinc is employed in many of the arts. It forms
ufeful alloys with fome of the other metals, fome of
which will be mentioned afterwards. It is alfo em¬
ployed in medicine. The fulphate of zinc is fome¬
times exhibited as an emetic, and frequently ufed in
folution as an eye-wafh. The oxide of zinc, or the
flowers of zinc, have been preferibed as an antifpaf-
modic, and particularly in cafes of epilepfy.
Sect. XVI. Of Tin and its Combinations.
' 1. Tin has been known from the eariiefl: ages. It
was much employed by the Egyptians in the arts, and
by the Greeks as an alloy with other metals. Pliny
fpeaks of it under the name of white lead, as a metal
well known in the arts, and even applied in the fa¬
brication of many ornaments of luxury. He aferibes
to the Gauls the invention of the art of tinning, or
covering other metals with a thin coat of tin. The
alchemifts were much employed in their refearches
concerning tin. They gave it the name of Jupter,
from which the falts or preparations of tin 'were called
jovial. Since their time, the nature and properties of
tin have been particularly invefligated by many che-
mifts, and it has proved the fubjefi; of fome important
difeoveries in chemical fcience. So early as the year
1630, John Rey threw out a conjefture, that the air
w~as fixed in this metal during its calcination. Boyle,
towards the end of the fame century, attempted to ac¬
count for the increafe of wTeight which this metal ac¬
quired during this procefs 3 but this was only fully af-
certained by Lavoifier, wrho repeated the experiment
of Boyle, and calcined the metal in clofe veflels 3 but
the method of conducing this experiment and the re-
fult of it, have been already detailed.
2. Tin exiffs in nature in three different ftates. It
is found native, in the ftate of oxide, and in that of
fulphurated oxide. Native tin is in brilliant plates,
or regularly cryftallized. The native oxide of tin,
which is the moft common ore of this metal, exifts
under a variety of forms. It is generally found cry¬
ftallized. The fulphuret of tin is of a pale or dark
gray colour, and when pure, has fome refemblance to
an ore of filver.
3. To obtain the metal from its ores, they are firft
roafted, and then treated with a flux, to reduce the
metal. It has been recommended by fome, to mix a
fmall quantity of pitch with the fufed mafs, to prevent
the oxidation of the tin. After the ore is roafted, it
fufes readily wdth three times its weight of black flux,
and a little decrepitated muriate of foda.
In the humid way, native tin may be diffolved in
nitric acid, which readily oxidates, and reduces it to
the ftate of white powder, which is an oxide of tin 3
and if it contain iron and copper, thefe tw7o metals re¬
main in the folution-
4. Tin is of a white colour, nearly as brilliant as
filver. The fpecific gravity of tin is 7.291. It is
one of the fofteft of the metals. It may be feratched
with the nail, and eafily cut with a knife. It is ex¬
tremely flexible, and produces a peculiar noife when
it is bent or folded. It is fo malleable, that it can be
eafily beaten out to to^o Part °f 311 inch, which is
the thicknefs of tinfoil. It has little elafticity or te¬
nacity. A wire of this metal about VW an inch
in diameter fupports a weight of about 3olbs. without
breaking.
5. Tin is fufeeptibie of very confiderable expanfion
by means of caloric, and on this account it has been
propofed to employ it as a pyrometer. Tin is one of
the moft fufible of the metals, and melts at the tem¬
perature of 4420, but it requires a very high tempera¬
ture to raife it in vapour. If it be allowed to cool
flowly, and when the furface becomes folid by pouring
out part of the liquid metal, cryftals are formed, in
large rhomboids, compofed of a great number of fmall
needles.
6. Tin is a good conductor of eledlricity- It
poffeffes a peculiar odour, which is communicated
to the hands by friftion. It has alfo a perceptible
tafte.
7. When this metal is expofed to the air, it is foon
tarniftied, and affumes a grayifh white colour ; but it
undergoes no farther change. When it is melted in
an open veffel, it is foon covered with a grayifli pel¬
licle, which is the commencement of the oxidation of
the
Tin, &c.
——'r—1
1788
Ores.
1789
Analyfis.
1790
Properties
179?
A<5tion of
heat.
1792
Odour, See.
1793
Oxidation,
6*4
CHEMISTRY.
Tin, See, the metal. When this pellicle is removed, another
forms, and fo on fucceflively till the whole is oxidated.
By continuing the heat, and by agitation, the procefs
goes on more rapidly, and the metal is converted into
a whitifh powder. This oxide contains about 20 parts
of oxygen in 100 of the metal. With the addition of
lead to promote the oxidation, this oxide is the putty
of tin. It contains about two parts of oxide of lead,
and one part of oxide of tin. But when tin is ftrongly
heated, it is converted into a fine white oxide, which
during the procefs gives out a vivid white flame. This
oxide is condenfed in the cold, and cryftallizes in fliin-
ing tranfparent needles.
According to Proud:, tin combines with two pro¬
portions of oxygen, thus forming two oxides. The
yellow oxide, which has the fmaller proportion of oxy¬
gen, may be prepared by difiblving tin in nitric acid
diluted with water, without the aid of heat. By preci¬
pitating the oxide with pure potafli, it is obtained in
the form of a yellowifti powder. Its component parts
are thofe already ftated, namely,
20 oxygen,
80 tin,
100
By diflblving tin in concentrated nitric acid, with the
afliftance of heat, the whole is converted with effer-
vefcence into a white powder, which falls to the bot¬
tom of the veflel. The component parts of this oxide
are, 28 oxygen, and 72 of tin.
8. There is no a£Hon between tin and azote, hy¬
drogen, or carbone, nor is there any perceptible a&ion
between tin or its oxides and water.
9. Phofphorus combines very readily with tin, by
G P uret' projedting bits of phofphorus on melted tin in a cruci¬
ble. A phofphuret of tin is thus obtained, which
cryftallizes on cooling. This compound is of a filvery
white colour, may be cut with a knife, and extended
under the hammer, but foon feparates into plates.
The filings of this phofphurct are like thofe of lead,
and when they are thrown on red-hot coals, they take
fire, and burn with the fmell and flame of phofphorus.
By the adlion of the blow-pipe the phofphorus only
burns, and the fmall metallic button which remains is
furrounded with a tranfparent glafs. Pelletier diftil-
led this phofphuret often with hyperoxymuriate of
mercury, and obtained a fuming muriate of tin, with
•the mercury reduced to the metallic ftate, and phof-
phorated hydrogen gas, which exploded as it came in
contadl with the air. There remained in the retort a
fpongy inflammable matter, which he fuppofed to be a
compound of tin and phofphorus.
Sulphuret. I.0, Sulphur combines very readily with tin, by
adding the fulphur to the metal while in a ftate of fu-
fion. This codipound forms a grayifh or bluifti mat¬
ter, which has a metallic luftre, a lamellated ftruc-
^ ture, and ciyftallizes in cubes, or in oftahedrons.
Compofi- 11 is decomPofed by acids with effervefcence. The
tiop. component parts are, according to
Bersrman. Pelletier.
Tin, 80 85
Sulphur, 20 15
ZOO 100
1794
Two ox¬
ides.
*795
11. If equal parts of oxide of tin and fulphur be
fufed together in a retort, fulphurous acid and fome
fulphur are difengaged, and there remains in the veffel
a compound of a brilliant golden colour. It cryftal¬
lizes in fix-fided plates. It is not a61ed on by the
acids. When it is ftrongly heated, it gives out ful¬
phurous acid and fulphur, and there remains behind a
black mafs which is fulphuret of tin. This compound,
which is a fulphurated oxide of tin, was formerly di-
ftinguiftied by the name of aurum mufvum, inufcum,
or mofaicum. The component parts of this fulphurat¬
ed oxide of tin are,
Tin, 8tc.
1798
Sulphura¬
ted oxide.
Oxide of tin, 60
Sulphur, 40
100
12. Tin enters into combination with many of the
metals, and forms alloys with them, fome of which
are of great importance. It alfo combines with acids, 1799
and forms falls. The affinities of tin and its oxides
are in the following order.
Tim.
Zinc,
Mercury,
Copper,
Antimony,
Gold,
Silver,
Lead,
Iron,
Manganefe,
Nickel,
Arfenic,
Platina,
Bifmuth,
Cobalt,
Sulphur.
Oxide of Tin.
Tartaric acid,
Muriatic,
Sulphuric,
Oxalic,
Arfenic,
Phofphoric,
Nitric,
Succinic,
Fluoric,
Sacladlic,
Citric,
La£Uc,
Acetic,
Boracic,
Pruffic.
I. Salts of Tin.
1. Sulphate of Tin.
1. Sulphuric acid afls very feebly on tin in the cold. Twcffu!-
The acid, however, is at laft decompofed j its oxygen phates.
combines with the metal, fulphurous acid gas is emit¬
ted, and the oxide falls to the bottom in the ftate of
white powder. In this cafe, the oxide has the fmaller
proportion of oxygen, and then the folution is more
permanent. There is no precipitation by water.
2. But when the folution of tin infulphuric acid is pro¬
moted by the action of heat, the acid is ftill farther de¬
compofed j a greater quantity of fulphurous acid is given
out, and fulphur is depofited. In this cafe the white
oxide of tin is formed. This compound, when evapo¬
rated, affumes the form of a jelly, and does not cry-
ftallize by the addition of water. It is precipitated in
the form of white powder. The firft might be called
the yellow fulphate of tin, and the fecond the white
fulphate of tin.
2. Sulphite of Tin.
When tin is immerfed in liquid fulphurous acid, it
affumes a yellow colour. At the end of fome days it
becomes
* Fourcray
Connaijs.
Chim. vi.
p. 30.
1801
Hiftory.
C H E M
Tin, 8cc. becomes black like charcoal, and there is depofited in
V 1 the liquid a black powder. In this procefs part of the
fulphurous acid is decompofed; its oxygen combining
with the metal, forms an oxide, which enters into
combination with another part of the acid, and forms
the fulphite of tin. A portion of fulphur is depofited
along with the white fulphite, which is not very folu-
ble, and another portion remains in folution with part
of the fulphite, forming a fulphurated fulphite. A
third portion of the fulphur combines with part of the
metallic tin, and forms a black fulphuret, on which
the acid has no aftion *.
3. Nitrate of Tin.
1. Nitric acid produces a very violent aftion with
tin. It is accompanied with great heat, and the evo¬
lution of nitrous gas. The metal is converted into a
white oxide, which gives to the liquid the appearance
of coagulated milk. It had been long obferved by
chemifts, that the folution of tin in nitric acid was
not permanent, for by evaporating or concentrating
the folution, the oxide is always precipitated. This
difficulty has been folved by the difcoveries of modern
chemiftry.
2. If tin be diflolved in nitric acid, diluted with wa¬
ter, and the great increafe of temperature moderated
by the application of cold, as by immerfing the veffel
in cold water, a folution of a fmall quantity of the
oxide of tin is effected. The folution is of a yellow
colour, and contains the oxide of tin, with a fmaller
proportion of oxygen, which is the yellow oxide. In
this procefs the tin is chiefly oxidated by the decompo-
fition of the water. In this procefs too, ammonia is
formed from the azote of the acid combining with the
hydrogen of the water. This becomes perceptible
by adding potaffi to the liquid. When the folution
is heated, the oxide of tin is feparated in great abund¬
ance.
3. But when nitric acid is more concentrated, a more
violent a£lion takes place between this acid and tin.
The metal is oxidated, and the whole of it feparates
from the liquid. To one part of pure nitric acid Guy¬
ton added !-§- of tin in a retort, when a violent effer-
vefcence took place, but no gas was given out. In this
experiment a quantity of ammonia equal to ~ of the
weight of the acid and tin employed, wras formed. The
acid and the water are decompofed, and the oxygen
of both combines with the tin, and forms an oxide,
while the azote of the acid and the hydrogen of the
water combine together and form ammonia. In this
ftate of oxidation, the tin does not combine with the
acid.
1802
Prepara¬
tion,
1803
In different
proportions.
4. Muriate of Tin,
1804
Prepara¬
tion,
r. Concentrated muriatic acid diffolves tin, either
in the cold or with the affiftance of a gentle heat. The
acid is foon deprived of its fuming property, and of
its yellow colour. A flight effervefcence takes place,
which is owing to the decompofition of water, and the
evolution of a fetid hydrogen gas. This peculiar
odour is fuppofed to be occafioned by the hydrogen gas
holding in folution a portion of the metal. Muriatic
acid diffolves more than 4 its weight of tin. No pre-
1805 cipitate is formed, as with the other acids. When it is
Properties, evaporated, it furnifhes cryftals in the form of brilliant
l
I S T R Y. 655
needle-ffiaped prifms, which are deliquefeent in the Tin, &c.
2. This muriate of tin is precipitated by the alkalies lSo<’
in the form of a copious white oxide, which is re-dif- 1*
folved with an excefs of alkali. The alkaline folution
is of a browniffi yellow colour. The fulphuret of am¬
monia precipitates this fait in the form of powder, which
becomes black as it dries, and by diftillation yields am¬
monia and aurum mujivum. The fulphuret of potafli
produces a yellow precipitate, which, by diftillation
furnifhes fulphurous acid and fulphur, and what remains
is converted into aurum mujivum, or the fulphurated
oxide of tin. This oxide precipitated by means of
foda, and diftilled with its weight of fulphur, yields
fulphurous acid gas, fulphur, and the refiduum is au¬
rum mujiyum. l8o^
3. This folution of tin abforbs oxygen, with the evo- Abforbs
lution of heat, from oxymuriatic acid, which is deprived oxygen,
of its odour. With nitric acid, a violent effervefcence
takes place. Nitrous gas is difengaged, and in both
thefe cafes, the oxide of tin combines with an additional
portion of oxygen. With the addition of fulphurous .
acid, this folution of tin depoflts the yellow fulphurated
oxide of a fine bright colour. This folution converts 1808
arfenic acid into the metallic ftate, and it produces the ^orrns a.n
fame effeft on the molybdic and tungftic acids, by ate,mUri
combining with their oxygen. The red oxide of mer¬
cury, the hyperoxymuriate of mercury, the white
oxide of antimony, the oxides of zinc and filver, are
all reduced to the metallic ftate by being deprived
of their oxygen by the muriate of tin. This muriate
alfo precipitates from the folution of gold, the purple
powder of Cajjius, by attra£ling that portion of oxygen
which renders the oxide of gold foluble. In all thefe
proceffes, the refults of which were afeertained by Pel¬
letier, the muriate of tin is converted into an oxy-
muriate^ _ _ < _ 1809
4. This oxymuriate of tin is formed by making a Formed by
ftream of oxymuriatic acid gas pafs into a folution of another
muriate of tin. It is alfo prepared by triturating equalProce^s*
parts of an amalgam, confifting of two parts of tin, ancl
one of mercury, and muriate of mercury, or corrofive
fublimate, and diftilling this mixture in a glafs retort,
with a very moderate heat.. A colourlefs liquor firft
paffes over, which is followed with the hidden evolu--
tion of a white vapour, which lines the infide of the re¬
ceiver. This vapour is condenfed into a tranfparent
liquid, which, in the air, exhales a copious, heavy,
white vapour, from which this liquid has been called
the /making liquor of Libavius, or the oxymuriate of
tin. When this liquor is included in a veffel, it no
longer gives out any vifible vapour, but it depofits at
the top of the veffel needle-fhaped cryftals, while fimi-
lar cryftals are precipitated to the bottom. Water does
not precipitate the fuming muriate of tin. When it is
thrown into water, it produces a noife fimilar to that
which is occafioned by concentrated fulphuric acid. A
number of tranfparent bubbles of air being evolved
from the mixture, coiled! on the furface, and be¬
come white by the contadl of air. By agitating the
water, they are more readily diffipated, and the liquid
fumes no longer. xSicr
5. Nitromuriatic acid, which is compofed of oneInnjtro—
part of nitric acid, and *two or three of muriatic acid, mui'iaftc*
very readily diffolves tin. A ftrong heat is produced,
which
656 C H E M I
Tin, See. which may be moderated by xmmerfing the veffel, in.
which the folution is made, in cold water. The me¬
tal Ihould be added in {mall portions, and one part
fhould be diflblved before the addition of another. In
this way the acid will diflblve half its weight of tin.
It is by this procefs that the muriate of tin is obtained
for the purpofe of dyeing fcarlet j but it is found to
vary confiderably in its effe&s, which, no doubt, de¬
pends on the ftrength of the acids employed, and the
different proportions in the mixture. This folution is
almoft always coloured. Sometimes it affords a gela¬
tinous mafs on cooling, which becomes in time more
folid. Sometimes it is of a white colour like milk.
This folution has not the fetid odour of the Ample folu¬
tion of tin in muriatic acid. It often happens, that it
does not affume the vifeid or folid form, without the ad¬
dition of 4- its weight of water. It is then {lightly
opaque, which is owing to the precipitation of part of
its oxide. When this folution is heated, an effervef-
cence take place j the tin is more ftrongly oxidated,
and it is generally after this procefs that it affumes the
form of a tranfparent jelly.
5. Fluate of Tin.
Fluoric acid has very little aftion on tin, but it dif-
folves its oxide, and forms with it a folution -which af¬
fumes a gelatinous form. The fluate of tin may be
alfo obtained by adding a folution of an alkaline fluate
to a folution of tin in muriatic acid.
6. Borate of Tin.
By a fimilar procefs boracic acid combines with
the oxide of tin, and forms a borate of tin, which is
infoluble.
7. Phofphate of Tin.
S TRY.
10. Acetate of Tin. ,
Acetic acid diffolves only a fmall portion of tin j
but when the acid is boiled on tin, the action is more
powerful, and the folution, which is of a whitifli co¬
lour, affords by evaporation fmall cryftals. The folu¬
tion of tin in acetic acid fometimes does not cryftallize,
but affords only a gelatinous mafs •, fo that, by the ac¬
tion of acetic acid on tin, the metal is either in dift'er-
ent degrees of oxidation, or there are different propor¬
tions of the acid and bafe.
11. Oxalate of Tin.
Oxalic acid added to tin in thin plates or filings,
firft blackens the lurface, which is afterwards covered
with a white powder. The oxalate of tin, which is fo-
luble in water, has an auftere metallic tafte. By flow
evaporation it furnilhes needle-ffiaped or prifmatic cry¬
ftals. When it is more rapidly evaporated, it affords a
tranfparent mafs like horn.
12. Tartrate of Tin.
Tartaric acid diffolves the oxide of tin, but the na¬
ture of this fait has not been examined.
13. Tartrate of Potafli and Tin.
This triple fait may be obtained by boiling together
the oxide of tin and tartar, in water. It is a foluble
fait, and cryftallizes with difficulty. It is not preci¬
pitated by the alkalies or the alkaline carbonates.
14. Benzoate of Tin.
This fait is formed by adding to a folution of tin in
muriatic acid, benzoate of potafli. The benzoate of
tin is precipitated, which is foluble in wrater, with the
afliftance of heat.
This fait may be formed by precipitating the oxide
of tin from its folution in muriatic acid, by means of
an alkaline phofphate. A phofphate of tin is thus ob¬
tained, which is infoluble in water.
8. Carbonate of Tin.
15. Succinate of Tin.
The oxide of tin is diffolved by fuccinic acid with
the affiftance of heat. When the folution is evaporat¬
ed, it affords thin tranfparent cryftals of fuccinate of
tin.
This fait is prepared by precipitating the oxide of
tin from its folution in muriatic acid, by means of the
carbonates of the alkalies. When this carbonate of
tin is diffolved in an acid, it effervefees j but, accord¬
ing to Bergman, the oxide of tin, precipitated by an al¬
kaline carbonate, is not found to have received any
fenfible addition of w-eight, fo that the effervefcence oc«
cafioned by the action of an acid, on what is fuppofed
to be a carbonate of tin, probably depends on the decom-
pofition of the acid itfelf.
9. Arfeniate of Tin.
Arfenic acid, with a moderate heat, diffolves a fmall
quantity of tin, and the folution affumes the form of a
jelly. Arfeniate of tin is formed, by adding to a folu¬
tion of tin in muriatic acid, an alkaline arfeniate. A
precipitate is formed, which is arfeniate of tin in the
ftate of infoluble powTder.
All the metallic acids are decompofed by means of
tin. They alfo combine with the oxide of tin, and
form falts in the ftate of pow'der, which has little fo-
lubility.
I
II. Adlion of Alkalies, &c. on Tin.
1. Tin in the metallic ftate is'little changed by t^e^^a8^eIs
adlion of the alkalies j but the oxides of tin readily com¬
bine with thefe bodies. The combination of the oxide
of tin with the fixed alkalies is effefted, either in the
dry or humid wray ; and with the affiflance of heat the
oxide of tin combines with liquid ammonia. This
combination takes place moft readily when the oxide is
recently precipitated, when it is in the ftate of minute
divifion.
2. The oxide of tin combines with the earths by fu-^1^*
fion ; and with the addition of a fixed alkali, forms an ' *
opaque vitreous mafs, which is employed lor the pur-
pofes of enamel.
3. Moft of the falts are decompofed by means of tin,ga^s
in confequence of the ftrong affinity of this metal for
oxygen. All the fulphates, when heated with this
metal, are more or lefs rapidly converted into fulphu-
rets. Equal parts of fulphate of potafti and tin, heated guj^2ia^es
together in a crucible, afford a greemfti coloured mafs,
which has no metallic appearance, and which feems to lgr ,.
be a fulphuret of potafti and tin. The nitrates pro-titrates, -
duce
C H E M I S T R Y.
6
i8i()
Muriates.
Tin, See. duce deflagration with this metal, with the atTiftance of
”““‘v 1 " ’ heat. If the tin be melted in a crucible, and brought
to a red-heat, and dried nitre in powder be projected
into it, a white brilliant flame is produced, and when
the detonation has entirely ceafed, the tin is found to
be oxidated. This experiment may be alfo made, by
mixing together tin filings with three parts of nitre in
powder, snd projedHng the mixture into a red-hot
crucible. Muriate of ammonia is decompofed by tinj
and by adding fulphur, the fulphurated oxide of tin, or
aurum mufivum, is obtained. Eight parts of tin united
to eight parts of mercury, with fix of fulphur, and four
of muriate of ammonia, afford, according to the proceis
of Pelletier, a very beautiful aurum mufivum.
It was obferved by this philofopher, that during the
procefs, fulphurated hydrogen gas, fulphuret of am¬
monia, and muriate of tin, were produced ; that the
tin oxidated and united to the fulphur, formed aurum
mufivum ; and that a part of this matter, compofed of
the different fubitances, in a ftate of vapour, was depo-
‘fited in lamellated, hexangular cryflals in the upper
part, and in the neck of the retort.
I he alkaline hyperoxymuriates, but efpecially that
of potafli, produce a violent detonation with this metal.
I hree parts of this fait mixed wdth one of tin in fine
powder, rapidly deflagrates wdien brought into contact
with a burning body. During this combuftion, there
is a brilliant and fudden flame, and the metal is reduced
to the ftate of vapour. The fame mixture by percuf-
fion produces a violent detonation with a confiderable
flame in the dark.
Many of the metallic folutions and metallic falls are
decompofed by means of tin, and are either reduced to
the metallic ftate, or deprived of a confiderable por¬
tion of their oxygen.
III. Alloys.
it Tin and arfenic form an alloy by fufion. The
compound, when the proportion of arfenic is confider¬
able, is w’hite, brittle, more fonorous and harder than
tin. In the proportion of 15 parts of tin and one of
arfenic, the alloy cryftallizes in large plates, is more
infufible than tin, and more brittle than zinc. By ex-
pofure to the air, and with the aftiftance of heat, the
arfenic is driven oft'.
2. With cobalt tin forms an alloy which is in fmall
grains, and of a light violet colour.
3. Tin combines with bifmuth. The tin is then
harder, more fonorous and brighter. The compound
in certain proportions becomes more fufible than either
of the two metals. The alloy of equal parts of tin
and bifmuth melts at 280°. Eight parts of tin and
two of bilmuth melt at 390°, and two of tin and one
of bifmuth at 330°.
Antimony. 4* Tin combines with antimony, and forms an alloy
which is white and brittle, and has a fpecific gravity lefs
than that of the two metals taken feparately. The
antimony gives hardnefs to the tin, and changes its tex¬
ture. This alloy is employed in many arts, and par¬
ticularly for the plates on which mufic is engraved.
5. Tin combines very readily with mercury, and in
all proportions. The tin is even diffolved when the
quantity of mercury is confiderable. 7’his union takes
place in the cold, but it is greatly promoted by means
of heat. The heated mercury is poured upon the tin
Vox. V. Part II.
1817
Arfenic.
1818
Cobalt.
iSrp
Bifmuth.
1820
1821
Mercury.
in fufion. The amalgam of tin is fufceptible of cryf-Lead,
tallization in the form of cubes. Sage oblerved the
cryftals of this amalgam in gray brilliant plates, thin
towards the edges, and leaving between them polygo¬
nal cavities.
This amalgam is employed for covering mirrors.
In applying it, tinfoil is fpread on a fmooth flat
ftone or table, and mercury in which a certain pro¬
portion of tin has been already diffolved, is poured up¬
on it. It is then fpread equally over the whole with
a feather or a piece of cloth. The plate of glafs, one
fide of which is to be covered, is then applied to
the edge of the table, and cautioufly moved along the
tinfoil, fo that the redundant part of the mercury
may be carried before it. What remains enters into
union with the tin. The glafs is then to be equally
loaded with weights, to prefs out any part of the mer¬
cury which may yet remain uncombined with the tin.
In the courfe of a few hours the amalgam of the tw-o me¬
tals adheres fo firmly to the glafs, that the weights may
be removed. 1824
6. Zinc readily forms an alloy with tin by fufion. Zlnc•
The compound affords a hard metal with fmall grains,
the duftility of which correfponds to the quantity of tin.
The alloy of tin and zinc forms part of the compound
which is known by the name of pewter. i82-
Tin is applied to a great many important purpofes.Ufes.
In the arts and domeftic economy, it is formed into a
great variety of veffels and inftruments. The alloys of
tin with other metals are not lefs important. It forms
a component part of type metal, and bell metal. The ox¬
ides of tin are employed for the purpofe of polifliing glafs
and metallic fubftances, and combined with the earths
and alkalies for the fabrication of enamels. The falls
of tin are employed for the preparation of colours in
dyeing, or as a valuable mordant for fixing certain co¬
lours. Tin in the metallic ftate has been exhibited as
a remedy againft worms. It is then granulated by con-
ftant agitation while it cools after fufion ; but it is fup-
pofed, if it produces any effeft as a vermifuge medicine,
that it is merely by its mechanical a&Ion.
Sect. XVII. OfL ead and its Combinations.
1824
1825
1. Lead has been known from the earlieft ages.Hittory
Pliny fpeaks of it under the name of black lead, pro¬
bably to diftinguifh it from tin, with the properties of
which he was alfo acquainted, for he obferves that it
was fometimes the pradice to contaminate tin with
lead.
2. Lead is found in great abundance in many parts0res-
of the world, and in a great variety of forms and com¬
binations. Lead has rarely, if ever, been found na¬
tive, and it is doubted whether it has yet been dif-
covered in the ftate of oxide. The moft common form
of lead is in the ftate of fulphuret, when it is combined
with fulphur. In this ftate it is of a gray, brilliant
colour, of a lamellated texture, very brittle, and breaks
into cubes. I his is the inoft frequent combination of
lead, and it is generally found in this ftate in veins.
Lead is alfo frequently met with combined with feveral
of the acids. The carbonate, phofphate, and arfeniate of
lead are not uncommon productions in the cavities of
the veins of fulphuret of lead. The chromate, molyb¬
date, and fulphate of lead are more rare.
40
3. The
65S
Lead, &c.
i8i5
Analyfis.
1827
?roperties.
1828
Aftion of
beat.
1829
Oxidation.
1830
Gray ox¬
ide.
1831
Yellow.
1832
Rod.
CHEMISTRY.
3. The fulphuret ofleacl, which is the moft common
ore, is reduced by roafting, and then fufing with black
flux. The other ores of lead are to be analyzed ac¬
cording to the nature of the acid with which they are
combined. To obtain lead in a ftate of purity, it may
be diilolved in nitric acid, and precipitated by means
of fulphate of foda. The precipitate, which is fulphate
of lead, is w’ell waflred, and reduced in a crucibles, by
fufing it with three times its weight of black flux.
4. Lead is of a grayifh or blulfli white colour. It
has confiderable brilliancy, but it foon tarnifhes when
expofed to the air. rI he fpecific gravity of lead is
11.352. It gives out a peculiar odour when it is rub¬
bed ; it has at firfl: fcarcely any perceptible tafte ; but
a difagreeable impreflion after fome time remains on
the tongue. When it is taken internally, it produces
violent effefts on the animal economy, even in very
fmall quantity. The colica pi&onum or dry belly-
ach of the Weft Indies, or, as it is called in this coun¬
try, mill-reek, which is a violent affeftion of the
bowels, is occafioned by this metal being taken inter-'
nally, either combined with fome liquid, or in the
ftate of vapour. This terrible difeafe often termi¬
nates in palfy. Lead ftains the finger or paper of a
bluilh colour. It is one of the fofteft of the metals.
It may be fcratched with the nail or cut with a knife.
It poffeffes confiderable malleability, and may be re¬
duced to plates thinner than paper. It has no great
duffility, and its tenacity is lefs than that of the other
metals, A lead wire of about TV of an inch in dia¬
meter can fupport only a weight of about i81b.
5. Lead is very fufible. It melts at the tempera¬
ture of 540°, or, according to the eftimation of Guy¬
ton, at 5940. When it is kept a long time melted,
and at a red heat, it fublimes, and evaporates in the
air. By flow cooling it cryftallizes in quadrangular
pyramids compofed of oftahedrons.
6. When lead is expofed to the air, it foon tar-
nilhes, is deprived of its luftre, and becomes firft of a
deep gray, and afterwards of a grayilh white colour *,
but this procefs is extremely flow, for the white cruft
which is formed on the furface defends the metal from
the atftion of the air, and its farther oxidation by ab-
forption of oxygen.
When lead is melted in the open air, and heat con¬
tinued, an iridefeent pellicle is formed on the furface,
which afterwards afifumes a uniform gray colour.
When this is removed, another pellicle is formed, and
in this w'ay the whole may be converted into an oxide.
When thefe pellicles are heated and agitated together,
the whole is converted into a grayifli powder, mixed
with yellowiih or greenifh fpots. This is the gray
oxide of lead, which is the firft ftate of its oxidation.
When the gray oxide of lead is more ftrongly heat¬
ed in contaft with air, it abforbs a greater quantity of
oxygen, and is converted into a yellow oxide, which
is known in the arts by the name of majjicot. It
contains about nine parts of oxygen in the hundred.
This oxide which is much employed in fome of the
arts, is prepared in the large w'ay, by conftantly agi¬
tating it while heated, in contaft with air, without ap¬
plying fo great a heat as to reduce the metal to the
ftate of the next oxide.
If this oxide of lead be reduced to a fine powder,
and expofed to a ftrong heat in a furnace for about Lead, &to
50 or 60 hours, it is converted into a red powder' Y—J
which is well known by the name of minium, or red
lead. The heat neceffary for this converfion is that of
a cherry-red, in a reverberatory furnace. 1833
Lead is fufceptible of combining with another por-h1'own*
tion of oxygen, and of forming another oxide. If a
quantity of red oxide of lead, according to the pro¬
cefs of Prouft and Vauquelin, be put into a veffel with
water, and oxymuriatic acid gas be pafled through it,
the oxide affumes a deeper colour, and is difiolved.
By adding potalh to the folution, the lead is precipi¬
tated of a brown colour, which is the browm oxide of
lead. It is of a ftiining brown colour, and is com¬
pofed of
Lead 79
Oxygen 21
100
By the aflion of the blow-pipe it becomes yellow, and
melts. On burning coals it is reduced, and when
heated in a retort, gives out pure oxygen gas, and is
converted into a vitreous matter. It inflames fulphur
by triturating it with the oxide, and gives out a bright
flame. ^
7. When lead has been converted into an oxide,
and when this oxide is expofed to a more violent heat,
it melts into a kind of glafs, or femivitrified matter.
In this ftate it is known by the name of litharge. It
confifts of fmall reddiih brilliant feales, which from the
colour is called litharge of gold. When it has been
expofed to a greater degree of heat, and is more vitri¬
fied, it is diftinguilhed by the name of litharge of fiver.
8. There is no aftion between lead and azote, hy¬
drogen or carbone. Water has no a£lion on lead, but
it feems to promote the oxidation of this metal, when
it is in contadft with air. Leaden veflels which are
frequently moiftened with water, are covered with a
white cruft when expofed to the air.
9. Lead combines with phofphorus, and forms p]10fp|iu„
with it a phofphuret. This may be prepared by ret.
projecting phofphorus on lead melted in a crucible,
or by diltilling pholphorus with lead in a retort. The
phofphuret of lead is of a filvery white colour, with
a little of a bluiih fliade. It is of a lamellated ftruc-
ture, and may be feparated in plates by hammering.
It is fo foft that it may be cut with a knife. It is
foraewhat kfs fufible than the component parts. Du¬
ring its fufion, a fmall quantity of phofphorus fepa-
rates, and takes fire on the furface. The component
parts of this phofphuret are,
1836-
Lead 88 Compoli-
Phofphorus 12 tion.
I GO
10. Sulphur combines readily with lead, either byguiphuret.
melting fulphur and lead together in a crucible, or by
throwing iulphur on melted lead. A black matter is
thus obtained, of a brilliant appearance, fibrous texture,
and lefs fufible than lead. This compound is brittle,
and refembles the native fulphuret of lead, ox galena.
The component parts of this fulphuret are,
Lead
Lead, &c.
C H E M I
Lead 86.8
Sulphur 13.2
100.0
1838
Affinities.
II. Lead enters into combination with the metals,
and forms alloys, and with the acids, and forms falts.
The order of the affinities f lead and of its oxide is
the following.
Lead.
Gold,
Silver,
Copper,
Mercury,
Bifmuth,
Tin,
Antimony,
Platina,
Arfenic,
Zinc,
Nickel,
Iron,
Sulphur.
Oxide of Lead.
Sulphuric acid,
Saclaftic,
Oxalic,
Arfenic,
Tartaric,
Muriatic,
Phofphoric,
Sulphurous,
Suberic,
Nitric,
Fluoric,
Citric,
Ladfic,
Acetic,
Boracic,
PrufTic,
Carbonic.
I. Salts of Lead.
fh'epaia-
~tion.
1840
Compofi-
tion.
* Min.
Wat. p.
274.
t Efay^
ii. 131.
¥ranjl.
1841
■Prepara-
ticn.
i. Sulphate of Lead.
Sulphuric acid has no adfion on lead in the cold,
but when lead is boiled with the acid concentrated, it
decompofes it, and fulphurous acid gas is difengaged
with effervefcence. The lead is converted into a white
thick mafs, which remains at the bottom of the veffel.
Sulphate of lead may alfo be obtained by adding ful-
phuric acid or an alkaline fulphate to acetate of lead.
This fait is precipitated in the ftate of a white powder.
The white mafs obtained by the firfl procefs, being
wafhed with water feparates into twro portions, one of
which is oxide of lead containing a little fulphiaric
acid, and the other portion, which is fulphate of lead, is
foluble in water, and may be obtained cryftallized in
needles. The fpecific gravity of this fait is 1.8742.
It has fcarcely any tafte. It is found native, and cry-
ftallized in regular oftahedrons, or four-fided pyramids,
or tranfparent tables. The component parts of native
fulphate of lead are, according to
Kirwan. Klaproth.
Oxide, 75-00 70-50
Acid, 23.37 25.75
Water, 1.63 2.25
100.00* 98.50 f
This fait is deprived of great part of its acid by
means of the alkalies.
2. Sulphite of Lead.
Sulphurous acid has no aflion on lead, but it com¬
bines readily with the oxide of lead, wdth a fmaller
proportion of oxygen. The red oxide of lead added
S T R Y. 659
to liquid fulphurous acid, foon becomes white; the bead, See.
acid is deprived of its odour, and there is formed a
faline mafs of fulphate and fulphite of lead. The ful-
phite of lead cannot be obtained feparately, but by
treating the white oxide of lead feparated from the
nitrate by means of fulphurous acid. The fulphite of *845
lead is taftelefs and inloluble. By the adlion of the Action of
blow-pipe on charcoal, it melts, gives out a phofphoric heat,
flame, and becomes of a pale yellow colour on cooling.
When it is heated for a longer time, it fwells up and
is entirely reduced to the metallic ftate. When diftilled
in clofe veflels, it gives out water, fulphuious acid, and
fulphur, and there remains behind, fulphate of lead of
a greenilh yellow colour. It is decompofed with ef¬
fervefcence and the evolution of fulphurous acid, by 1843
means of fulphuric and muriatic acids. It is not de- DecompoS-
compofed by nitric acid, but is converted into a ful-tl0n“
phate, and red fumes of nitrous gas are given out. If,
in place of treating the red oxide with fulphurous
acid, this oxide be expofed to a red-heat, along with
fulphite of foda, the oxide is reduced, and the ful¬
phite of foda is converted into a fulphate, but with
excels of foda, becaufe the fulphuric acid formed, can¬
not faturate the fame quantity of foda. Hence it ap¬
pears, that the red oxide of lead gives up part of its
oxygen to the fulphurous acid wThen it is uncombined,
and the whole of its oxygen to the acid, when it is
in combination with potaftr or foda *. * Foursroy,
3. Nitrate of Lead.
.... . . r844
1. Nitric acid, a little diluted wdth water, a£ls upon Pritpara-
lead, oxidates it, and difi'olves it with effervefcence.tlon’
If the acid be too ftrong, there remains behind a dry
oxide. This oxide is equally foluble in nitric acid.
No precipitate is formed in the folution by the ad¬
dition of water. It has at firft a fweetifh, then an af-
tringent, acrid tafte. By evaporating this folution, it
affords on cooling, regular cryftals in the form of flat
triangles ; and by flow, fpontaneous evaporation, the
angles are truncated. Sometimes fix-fided truncated prop!rPc$.
pyramids are obtained, wdth the faces alternately broad
and narrow. Thefe cryftals decrepitate ftrongly on
burning coals, and give out brilliant fparks. The
fait is decompofed, and a yellow or red oxide of lead
remains behind. Nitrate of lead is decompofed by the
alkalies, and precipitated in the form of white oxide.
It is precipitated of a black colour, by means of the
fulphurets and hydrofulphurets ; it is alfo decompofed
by fulphuric acid and the fulphates, which form a
thick, white, foluble precipitate of fulphate of lead.
Sulphurous acid alfo precipitates this fait in the form of
fulphate of lead. 1545
2. The former fait is a compound of nitric acid and With the
the yellow oxide ; Imt when nitric acid combines with p!,ute ox*
the white oxide, the fait cryftallizes in yellow colour-
ed brilliant feales, which are very foluble in water.
This fait may alfo be prepared by boiling together a
quantity of nitrate of lead with the yellow oxide, along
with lead in the metallic ftate. The lead deprives the
yellow oxide of part of its oxygen, and the whole is
converted into the white oxide, and combines with the
ac^* ....
3. But if nitric acid be poured on the red oxide of Action on
lead, heat is produced, the oxide becomes white, parted oxides
is diffolved, and part falls to the bottom in the form of
4 O 2 a
66o
CHEMISTRY.
Lead, See. a black powder. This powder is the brown oxide of
>, y—w jeac^ Wjt]1 greateft proportion of oxygen, part of
which it has derived from the red oxide, which is then
converted into the white. About 4 °f the red oxide
are diffolved in the acid, but are previoufly reduced to
the date of white oxide, and the oxygen which has
been given out, combines with the remaining 4, and
converts it to the date of brown oxide. Thus it ap¬
pears, that the red and the brown oxides of lead do not
form compounds with nitric acid. They mud be de¬
prived of a portion of their oxygen, and converted in¬
to the white or yellow oxides, before they are foluble
in this acid.
4. Muriate of Lead.
Muriatic acid afts feebly on lead or its oxide ; but
when it is heated with the latter, part of the oxide
combines with the acid, becomes foluble with ex-
cefs of acid, and affords crydals in the form of fhining
filky needles, which are not deliquefeent in the air, but
are foluble in water, and have an adringent tade.
This fait may be formed by adding an alkaline muriate
to a folution of nitrate of lead. A white thick precipi¬
tate is immediately formed. The muriate of lead thus
obtained, has a fweetifh tade, and is foluble in about 30
times its weight of water. When heated, it readily
melts, and gives out a white vapour, which condenfes
into a crydalline- powder. When this fait is melted,
it adumes the appearance of a femivitreous, duning,
grayifh mafs, which has been called plumbum corneu7Jiy
or horny lead. This fait is decompofed by fulphuric
acid. Its component parts are, according to
1849
Frepara-
tioo.
Coinpoii-
tion.
1850
Prepara¬
tion.
Klaproth.
Acid, 13.5
Oxide of lead, 86.5
Kir wan.
Acid,
Oxide of lead,
18.23
81.77
1849
With red
oxide.
100.0
100.00
1851
Properties.
2. When muriatic acid is flightly heated wdth the
red oxide of lead, the acid is converted into oxymuri-
atic acid •, while the oxide, deprived of part of its oxy¬
gen, unites to another portion of the acid, and forms
muriate of lead in the ftate of white powder.
5. Hyperoxymuriate of Lead.
When oxymuriatic acid gas is made to pafs through
■water, having a white, yellow, or red oxide of lead, it is
abforbed. The oxide becomes at firft black or brown,
and is then diflolved. The hyperoxymuriate which i$
formed, remains in folution of a yellow colour. This
folution being precipitated wdth potafli or foda, the
oxide of lead is depofited, of a reddifh browm colour.
1 his fait may be obtained by pouring oxymuriatic acid
on nitrate of lead. No precipitate is at firft formed, but
in the end a brownilh red powder appears. This fait
is more foluble than muriate of lead, and is readily de¬
compofed. The browm oxide of lead, which is ob¬
tained by decompofing this fait, according to the experi¬
ments of Vauquelin, poffeffes very different properties
from thofe of the other oxides of this metal. It is of
a deep, fhining, velvet-brown colour. Heated with the
blowr-pipe, it becomes yellow, and melts. On red-hot
coals it is reduced } it gives out pure hydrogen gas,
when it is heated in a retort, and there remains behind
a litharge of lead. It diffolves in nitrous acid, but is
infoluble in nitric acid. The addition of fugar, honey, Lead, See.
or fome vegetable matter, by depriving it of part of its 'Y'—
oxygen, renders it foluble in this acid.
6. Fluate of Lead.
This fait may be formed by pouring a folution of an
alkaline fluate into a folution of nitrate of lead. An
infoluble infipid fait is thus formed, which is decom¬
pofed by fulphuric, nitric, and muriatic acid?.
7. Borate of Lead.
This fait is formed in the fame way as the laft, and
is in the ftate of white powder. It melts before the
blow-pipe, into a colourlefs glafs.
8. Phofphate of Lead.
l8S3'
I. Liquid phofphoric acid adls very flowly upon Prepara-
lead, and converts it into a white, infoluble phofphate.ti0n*
It may be formed, however, by adding an alkaline
phofphate to the nitrate of lead. With an excefs of
acid this fait becomes fufible by heat, and when it
cools, afliimes the form of regular polyhedrons. It is
decompofed by red-hot charcoal, which converts it in¬
to phofphorus and lead, while the carbone of the char¬
coal is converted into carbonic acid. It is decompof¬
ed by fulphuric, nitric, and muriatic acids, and by the
alkaline carbonates.
This fait is frequently found native, cryftallized in Native.
fix-fided prifms, of a green or yellow colour. It is
foluble in pure foda, but infoluble in water. The
component parts of a phofphate of lead from Wanlock-
head in Scotland, according to the analyfis of Kla¬
proth, are the following.
Oxide of lead,
Phofphoric acid,
Muriatic,
80.00
18.co
1.62
99.62
9. Carbonate of Lead.
1. Carbonic acid which has no atftion on lead, com¬
bines wdth its oxide, which is converted into the car¬
bonate of lead ; or this fait may be prepared by the de-
compofition of a foluble fait of lead by an alkaline car¬
bonate. Thus precipitated, it is in the ftate of white
powder, wdrich has neither tafte nor fmell, and is in¬
foluble in w'ater, but it is foluble in pure potaftr.
2. This fait is frequently found native, of a whitiftr
colour, and cryftallized in tables, in fix-fided prifms,
or in regular oftahedrons. The fpecific gravity is
7.2357. It is infoluble in water. By the adlion of
the blow-pipe on charcoal, the acid is driven off, and
the lead is revived. The component parts of carbo¬
nate of lead, are, according to
* Zjfayst
ii- 125.
1ran/l.
lS54
Prepara¬
tion.
i855
Native.
Bergman.
Acid, 16
Yellow oxide, 84
100
Klaproth.
* 6-33
83.67
100.00
1856
3. Cerufe or white lead, which is employed as a white
paint, is a carbonate of lead, combined with a certain lead.
proportion
C H E M
Lead, See. proportion of oxide. It is prepared by expofing thin
plates of lead to the vapour of vinegar. A range of
pots are placed on tanners bark or horfe dung, that
they may receive a moderate heat. Thefe are cover¬
ed with plates of lead, which are full of holes. Ano¬
ther range of pots is placed above thefe, covered in
like manner with plates of lead, and fo on, till the
whole chamber is filled. The acid is decompofed ; part
of the lead remains in the Hate of oxide, while the
greateft proportion is converted into a carbonate, which
is the white lead of commerce.
10. Arfeniate of Lead.
When lead is digefted in a folution of arfenic acid,
the furface is blackened, and becomes covered with
a white powder. When lead filings are diftilled with
double their weight of folid arfenic acid, the mixture
melts into a tranfparent mafs. A fmall quantity of
arfenious acid is feparated, and there remains behind a
whitith glafs, which being diluted with water, lets
fall a white powder, whilft part of the arfenic acid is
diffblved. The lead in this cafe has deprived the ar-
fenic acid of part of its oxygen, and in the date of
white oxide has combined with another portion of the
acid. The arfeniate of lead is not foluble in w-ater.
By heat it fufes into a w'hite glafs. This fait is found
*857 native, and by the analyfis of Mr Chenevix it is com-
Coinpoli- pofed of
tion.
Acid, _ 33
White oxide, 63
Water, 4
100
11. Tungftate of Lead.
Tungftic acid feparates the oxide of lead from its
folution in nitric acid, and forms a tungftate of lead,
in the form of a white powder.
12. Molybdate of Lead.
When molybdic acid is added to the folution of
lead in nitric acid, it forms a copious white precipi¬
tate, which is molybdate of lead. This fait is found
native, and cryftallized in cubes or rhomboidal plates.
It is of a yellow colour, infoluble in water, but folu--
ble in fixed alkalies and nitric acid. It is decompofed
by muriatic acid. The component parts, as afeertain-
ed by Klaproth, are,
Acid, 34.7
Oxide, 65.3
100.0
13. Chromate of Lead.
An alkaline chromate mixed with the folution of
nitrate of lead, forms a precipitate in the ftate of red
powder, which is chromate of lead. This fait is
found native, of a reddilh yellow colour, and cryftal¬
lized in four-fided prifms, terminated by four-fided
pyramids. The fpecific gravity is about 6. It is fo¬
luble in the fixed alkalies, but infoluble in water. It
is decompofed by muriatic and fulphuric acids, but
diflblves without decompofition in nitric acid. Ac-
I S T R Y. 661
cording to the analyfis of Vauquelin, it is compo- Lead,
fed of —>
Acid, 34.9
Oxide, 65.1
100.0
14. Acetate of Lead.
. . . . v. lS58
1. The combination of acetic acid and lead was for-Names,
merly known by the names of exlraEi of Saturn, fait
of Saturn, fugar of Saturn, or fugar of lead. This
acid oxidates lead, and dilfolves the oxides with great l8
facility. It is formed by diffolving carbonate of lead Prepara-
or cerufe in acetic acid, or by expofing thin plates of tion.
lead to the a£tion of acetic acid in earthen veffels.
After the acid has been lufficiently faturated, and the
folution concentrated by evaporation, the acetate of
lead is depofited in fmall cryftals. 1S60
2. This-fait is in the form of fmall cryftals, -which Properties,
are flat, four-fided prifms, terminated by two-fided
fummits. It has an aftringent fweetifti tafte. The
fpecific gravity is 2.345. ^ not vei7 foluble in wa¬
ter, without an excels of acid. It undergoes no
change by expofure to the air. By its folution in wa¬
ter, a fmall quantity is depofited in the form of white
powder, which is a carbonate of lead, formed by the
carbonic acid which exills in the water. l^(^1
3. Acetate of lead is decompofed by fulphuric, mu* Decompofi-
riatic, fluoric, and phofphoric acids. It is decompo-don.
fed by heat. By diflillation it affords, according to
the experiments of Prouft, from 160 parts of the fait,
I 2 parts of flightly acidulated water ; with a greater
heat, 72 parts of a yellow liquid, having the odour
of alcohol, which had fomething of an empyreumatic-
fmell. Ammonia was difengaged, by adding lime to.
the liquid ; and when the liquid was faturated with
potaih, and remained at reft for 24 hours, a third part
of oil feparated, and floated on the furface. This oil,
which had a ftrong odour, was removed, and the 1:-*
quid diftilled with a moderate heat. The firft part
that came over mixed with -water like alcohol, and
was almoft as volatile as ether. When it was brought
into contaft with a burning body, it gave out a white
flame.
15. Oxalate of Lead.
Oxalic acid very readily tarnilhes lead, and at laft
corrodes it. It readily diffolves the oxide j and when
it is fatufated, the folution becomes thick, and depo-
fits fmall Ihining cryftals, which become readily
opaque by expofure to the air. This fait may be
formed by pouring oxalic acid into the folutions of ni¬
trate, muriate, or acetate of lead. It is fcarcely fo¬
luble in water, without an excefs of acid. The com¬
ponent parts are,
Acid, 41.2
Oxide, 58.8
100.0
16. Tartrate of Lead.
Tartaric acid combines with the oxide of lead, ett
forms a precipitate in the ftate. of an infoluble white
powder3 .
662
CHEMISTRY.
Lead, $cc. powder, from the folution of lead in nitric and muriatic
acids. It is compofed of
Acid, 34
White oxide, 66
* Ann. dc IOO *.
Chim.
sxxviii.37. 17. Tartrate of Potato and Lead.
This triple fait is obtained by boiling the oxide of
lead in tartar with water. It is infoluble, and is not
decompofed by the alkalies.
18. Citrate of Lead.
By adding citric acid to a folution of acetate of lead,
a citrate of lead precipitates in the form of powder,
which is fcarcely foluble in water.
19. Malate of Lead.
This fait is obtained by adding malic acid to a fo¬
lution of the nitrate or acetate of lead. The malatc
of lead precipitates in the form of fine light flakes. It
is foluble in acetic and diluted nitric acids.
20. Benzoate of Lead.
Benzoic acid has but a feeble a£!ion on lead. By
evaporating the folution, cryftals of a brilliant-white
colour are obtained, which are benzoate of lead. This
fait undergoes no change by expofure to the air, is fo¬
luble in water and alcohol, is decompofed by heat, and
by the fulphuric and muriatic acids.
, 21. Succinate of Lead.
Succinic acid combines with the yellow oxide of
lead, and yields flender foliated cryftals, which are nearly
infoluble in water, but foluble in nitric acid.
22. Saccolate of Lead.
When facla&ic acid is added to folution of nitrate of
lead, a white precipitate is obtained, which is facco-
late of lead.
23. Suberate of Lead.
Suberic acid forms a precipitate when added to the
folution of lead in acetic and nitric acids.
i26i
Promote
its oxida¬
tion.
1863
Combine
with the
oxide.
24. Ladtate of Lead.
La£lic acid, after it has been digefted upon lead
for fome days, diffolves a portion of it. The folu¬
tion has a fweet, aftringent tafte, but it does not erv-
ftallize.
II. A&ion of the Alkalies, See. on Lead.
The alkalies and earths have no aflion whatever on
lead. The alkalies, however, promote its oxidation
by the air, on account of the attraction which they pof-
fefs for the oxide of lead.
2. The alkalies and alkaline earths unite readily
with the oxide of lead. Lime water digefted fome time
With oxide of lead in the ftate of litharge, difiblves this
oxide better than the red. When the folution is eva¬
porated, it affords fmall, tranfparent, iridefeent cry¬
ftals, not more foluble than lime. The alkaline ful-
phates decompofe this compound of oxide of lead and
1
lime. It is alfo decompofed by fulphurated hydrogen lead, Sc
gas, and by fulphuvic and muriatic acids, which latter
convert the lead into a fulphate and muriate. This
folution blackens wool, the nails, hair, the white of an
egg; but has no a£Hon, and produces no change on
filk, on the ikin, or the yolk of an egg. It has been
obferved, that the Ample mixture of red oxide of lead
and of lime, which latter converts it to white, produ¬
ces a black colour on animal matters. It is fometimes
employed for dyeing the hair. It had formerly been
obferved by Bergman, that the cauftic fixed alkalies
diffolve the oxide of lead, which takes place when thefe
bodies are added in excefs to the precipitates of this me¬
tal from its folution.
3. The earths, but efpecially alumina and filica, rea-Earths,
dily combine with the red oxide of lead, by the aftion
of heat 5 and, when the proportion of oxide is confider-
able, the compound is a heavy, uniform, vitreous mafs,
which has been called g/a/s of lead. It is on account
of the ftrong tendency of the oxide of lead to vitrifi¬
cation, and which it communicates to earthy matters,
that it is employed in the compofition of glafs in the
proportion of from f to L. This oxide was only em¬
ployed formerly, for the preparation of enamels, and
for glazing pottery and ftone ware ; but it is now ge¬
nerally ufed after the example of the Englito manufac¬
turers, in the fabrication of glafs, in rnoft countries of
Europe. _ i853
4. Lead has no action on the fulphates. It burns Sulphate?,
flowly with the afliftance of the nitrates. When nitre, &-c'
in the ftate of fine powder, is thrown into melted lead,
raifed to a red heat, there is fcarcely any perceptible
flame ; and, when the a&ion has ceafed, the oxide is
found in fmall yellowifti femivitrified feales, fimilar to
thofe of litharge.
5. There is a perceptible a&ion between lead and Muriates,
the muriates, fome of which have given rife to feveral
important proceffes in chemiftry, and in the arts. It
had been long obferved, that a plate of lead immerfed
in water, faturated with muriate of foda, was foon co¬
vered with a cruft of white oxide. It was alfo known,
that the red oxide of mercury and litharge became
white when kept in contadf with muriate of foda dif-
folved in water. This prbeefs, which is promoted by
agitation, is one of the great defiderata of modern che¬
miftry, to be able to decompofe common fait for the
purpofe of obtaining the foda. It was at firft fuppofed,
that this was a partial decompofition, from which a
fmall quantity of muriate ,of lead only was obtained j
that the decompofition was aided by heat j and that it
was by this procefs that a brilliant yellow muriate of
lead, much employed in painting under the name of
Englif yellow, was prepared.
This fubjeft has been greatly elucidated by the ex-Decompofi-
periments and refearches of Vauquelin. He took fevention of mu-
parts of litharge reduced to powder, and one of mu-r‘ate0^
riate of foda mixed together, and moiftened with a fuf-loc*a'
ficient quantity of water, to reduce them to the liquid
ftate, and then agitated the mixture for feveral hours to
promote the reciprocal aftion. The oxide became
white, and increafed in volume, and the mixture ab-
forbing the wTater, became of a more folid confiftence.
Having added new quantities of w^ater during four
days, and diluted the whole in {'even or eight parts of
this
C H E M
Lead, See. this liquid, it was filtered. The liquid, which was
'-“■"v’-—^ now fenfibly alkaline, contained a little muriate of
lead, but no trace of muriate of foda. When it was
evaporated to of its bulk, it yielded cryftals of car¬
bonate of foda, which were opaque, by being contami¬
nated with muriate of lead. . The oxide of lead which
remained, had increafed about of the weight; it be¬
came of a fine citron-yellow colour, with a moderate
heat, and loll 0.025 of its weight. It was infolu-
ble in water. Soda diffolved a portion of this oxide,
as did alfo diluted nitric acid. By this means the mu¬
riate of lead was feparated pure and cryftallized ; and
the mafs which remained after the aiffion of muriate of
foda and lead, exhibited the charafters of a muriate of
lead containing an excefs of oxide.
From thefe experiments Vauquelin concludes, that
the litharge which has been employed in the decompo-
fition of fea fait, is a muriate of lead with excefs of
oxide *, that the cau'ftic alkalies diffolve this fait, but
do not decompofe it ; that the affinity of muriate of
lead for an excefs of the oxide of this metal, is the
caufe of the decompofition of muriate of foda by means
of litharge j that the excefs of oxide gives to the muri¬
ate of lead the property of a {fuming a brilliant yellow
colour by heat, a property which the fimple muriate of
lead does not poifefs; that the fame excefs of lead ren¬
ders it infoluble in water, and that this excefs may be
taken up by the nitric acid, which reduces it to the
ftate of ordinary muriate of lead. The fame philofo-
pher has confirmed thefe inferences, by fhewing that
cauftic foda decompofes the common muriate of lead,
only by bringing it to the ftate of muriate with excefs
of oxide, which is charaflerized by being in the form of
powder, and the yellow colour, which is communica¬
ted by heat, and its decompofition by nitric acid, which
converts it into nitrate of lead, and fimple muriate of
lead. Thus, it appears, that the oxide of lead decom¬
pofes the muriate of foda, by double affinity j namely,
by the affinity of the oxide for muriatic acid, and that
of the muriate of lead for an excefs of oxide. A con-
fiderable quantity of the latter, therefore, is necefiary
for the complete decompofition. Five-fixths at leaft
are required to form the muriate with excefs of oxide.
Litharge then decompofes fea fait completely, when in
fufficient quantity, while foda only decompofes the mu¬
riate of lead partially, and reduces it to the ftate of mu¬
riate with excefs of oxide ; but the carbonate of foda
lS6g effe&s the entire decompofition of this fait.
Muriate of 6. The decompofition of muriate of ammonia by
ammonia, lead, and efpecially by its oxide, has been long
known* The oxides of lead triturated with this fait
in a mortar in the cold, difengage ammonia, which is
very perceptible by its fmell. By diftilling a mixture
of one part of red oxide of lead and two of muriate of
ammonia in a retort, very pure cauftic ammonia is
obtained. If the red oxide has remained for any
length of time expofed to the air, it gives out, during
the procefs, a little carbonate of ammonia. The hy-
peroxymuriate of potafti produces a detonation with
kad. A mixture of three parts of this fait with one
of lead, gives out a vivid flame by percuffion. The
other falts, as the phofphates, fluates, &c. have no ef-
fe£t on lead. By the action of the blow-pipe, they
combine with its oxides, and form yellovvifti, or gray,
opaque, or tranfparent glafles.-
1 s T R Y.
663.
III. Alloys.
Lead, See.
1. Lead combines with arfenic by fufion, and the-wqtb arfe.
compound is a brittle lamellated alloy. When the ox-n;c.
ides of thefe metals are combined together by means
of heat, a vitreous mafs of a red colour is formed.
2. The alloys of lead with tungften, molybdena,
and the newly dilcovered metals, are not known. 187°
3. Cobalt feems to have little affinity for lead.
Equal parts of the two metals being fufed together,
were found, when the mafs cooled, to be in leparate
mafles. The heavieft metal occupied the inferior part
of the veffel, and the lighter the upper part. An alloy
of lead and cobalt has been formed by introducing co¬
balt in powder within plates of lead, and covering
them with charcoal, to exclude the air. A brittle
mafs, which aflumed a better polilh than lead, rvas
obtained from equal parts of the two metals, by the
application of heat. The two metals in different pro¬
portions afforded an alloy which differed in hardnefs,
fpecific gravity and malleability, according as the one
or the other metal predominated. 1872
4. Lead forms with bifmuth an. alloy of a clofe
grain, and a dark gray colour. This alloy, when the
bifnmth is not in great proportion, poffeffes confider-
able duftility. Bilmuth has the property of increafing
the tenacity of lead. The fpecific gravity of the al¬
loy of lead and bifmuth is greater than the mean. ,873
5. When lead is combined with one-eighth of its Antimony-
weight of antimony, it forms an alloy which poffeffes
great tenacity. When they are combined in equal
parts, the alloy is very brittle.- Two parts of lead
with one of antimony, give a brittle alloy in fmall
grains fimilar to thofe of iron. Four parts of lead
with one of antimony, afford an alloy of greater duc¬
tility, and in larger grains. Four parts of lead with
one-half of antimony, give a very foft metal in fine
grains like fteel, and having the fame colour. The
alloy of j 6 parts of lead and one of antimony, differs
only from lead in hardnefs. This alloy has a greater
fpecific gravity than the mean, and poffeffes confider-
able tenacity. It is employed in the fabrication of
printing types. 1875.
6. Mercury combines with lead very readily, and Mercury
in all proportions. An amalgam of lead and mercury
may be formed by triturating the former in filings
with the latter; or, by adding heated mercury to
lead in fufion. This amalgam varies in folidity, ac¬
cording to the proportion of the two metals. It is of
a white colour, is altered by expofure to the air, and
affords cryftals by cooling. The mercury is driven
off by ftrong heat, and when it is triturated with wa¬
ter, a black powder, which is oxide of lead, feparates.
The amalgam of lead and mercury becomes very li¬
quid, when it is triturated with the amalgam of bif- rC,,
muth. To equal parts of lead and bifmuth melted in ariCi bif-
an iron veffel, half the quantity of the whole mafs of muth.
hot fluid mercury was added, and the mixture w’as
agitated till it cooled. A fluid amalgam was thus ob¬
tained, which does not become folid by reft, or expo¬
fure to the air, and which almoft entirely paffes
through leather like mercury itfelf. This liquidity of
lead and bifmuth is aferibed to their increafed capacity
for caloric in a ftate of combination. When mercury
is thus fophifticatedj it may be dete&ed by obferving
ths
1S76
Tin.
1S77
Solder.
1878
Tin and
Wniuth.
1879
Ufes of
lead, See.
C H E M
tlie fmaller fpeclfic gravity, and fubjefting it to the
teft formerly mentioned, of pouring it along a fmooth
futface, when it is found to drag a tail.
7. An alloy of zinc and lead in equal parts is hard¬
er and whiter than lead, and is malleable. The lead
is rendered volatile by the zinc, while the latter is in
the proportion of 10 or 12 parts to one of the former ;
but if the zinc be in fmaller proportion, it feparates
from the lead. The fpecific gravities of the alloys of
zinc and lead are faid to be greater than the mean of
the two metals.
8. Lead combines with tin in all proportions.
Lead, in general, is found to increafe in denfity and
hardnefs, when alloyed with tin. Three or four parts
of tin with one of lead, according to Mufchenbroek,
form an alloy which poffeffes twice the hardnefs of
pure tin. The alloy of three parts of tin and one of
lead poflefles the greateft tenacity of any proportion
of thefe metals. Two parts of lead and one of tin,
compofe an alloy which is more fufible than either of
the metals. This is the compolition of common folder.
Tinfoil is a compound of tin and lead 5 and the fheet
lead employed for lining the boxes in which tea is
brought from China to Europe, contains a certain
-portion of tin, which gives it hardnefs. This, how-
'ever, is alfo found to be alloyed with zinc and bif-
muth.
One of the mod lingular alloys of lead is that with
bifmuth and tin, which has been called from its eafy
fulibility, the fujible alloy. Eight parts of bifmuth,
five of lead and three of tin, are the proportions pro-
pofed by Darcet for this alloy, which is fo fufible,
that it remains liquid at the temperature of boiling
water. This alloy cryftallizes by flow cooling.
Lead and its various preparations are applied to a
great variety of purpofes in the arts. In the metallic
Hate it is employed in the conftruftion of numerous
veffels. In the ftate of oxide it is ufed as a paint, and
in the fabrication of enamels for porcelain and pottery,
and in the preparation of coloured glafs and artificial
precious ftones. Some of its falts are of great impor¬
tance in the arts, as the acetate in dyeing, and the
carbonate or cerufe in painting.
The greateft caution ought to be obferved, how¬
ever, in the ufe of leaden veflels in domeftic economy,
in which fubftances are preferved which are to be ta¬
ken internally, particularly thofe which contain acids
that are apt to diffolve the lead ; and as the effefts of
lead are fo deleterious to the animal economy when ta¬
ken internally, this caution cannot be too ftriftly ob-
lerved.
1S80
Hiftory.
18S1
■Very aban-
.dant.
Sect. XVIII. Of Iron and its Combinations.
1. Iron is one of the moft important and moft ufe-
ful of the metals, and it is fortunately one of the moft
abundant. It is fuppofed that it was not fo early
known as fome of the other metals, which, on ac¬
count of their fcarcity and durability, have been held
in higher eftimation, and dignified 'with the name of
precious metals. But perhaps the difficulty of extraft-
ing and working iron prevented it from being fo gene¬
rally applied to thofe purpofes to which, on account of
its valuable properties, it is peculiarly appropriated.
2. Iron, as it is the raoft ufeful of the metals, fo,
I S T R Y.
as it has been obferved, it is the moft abundant, and Iron, See.
at the fame time the moft univerfally diffufed. Iron v—
exifts in five different ftates, but in thefe it exhibits
the greateft variety of any other of the metals. It is
found in the metallic ftate, in that of alloy with other
metals j in the ftate of fulphuret, in the ftate of ox¬
ide, and combined wuth the acids forming falts. jjg,
1. Iron has only been found native in infulated maffes, Ores,
one of which, difeovered by Pallas in Siberia, and
another, which was found in South America, long
occupied the attention of philofophers in fpeculations
and difeuffions concerning their origin. 'Phis point
remained unfettled till the difeovery of numerous other
fafts with regard to fimilar productions, which have
proved, whatever may have been their origin or mode
of formation, that thefe metallic maffes have fallen from
the atmofphere. 2. Iron is frequently found in the
ftate of alloy with other metals \ but in this ftate it is
generally in very fmall proportion. 3. Combined
with fulphur. This compound, or fulphuret of iron,
wffiich is known to mineralogifts by the name of pyrites t
is a frequent production among the ores of iron. Sulphu-
retof iron is found cryftallized in a great variety of for ms.
Iron is alfo frequently found combined wuth car bone.
This compound, now diftinguifhed by the name of car¬
buret of iron, was formerly known by the name of
black lead, or plumbago. 4. But the moft ordinary
ftate of iron is that ot oxide, and in this ftate it ex¬
hibits a great variety of forms. It is fometimes in ir¬
regular and infulated maffes 5 fometimes regularly
cryftallized, and difpofed in veins. 5. The native falts
of iron are very numerous. It has been found in the
ftate of fulphate, phofphate, carbonate, tungftate, and
pruffiate, and there is reafon to believe, that it exifts in
combination wfith many other acids. ^
3. The method of affaying iron ores, or of extrafling Analyfis.
the metal from thefe fubftances with which it is com¬
bined, varies according to the nature of the ore. It is
firft reduced into powder, and expofed to heat, to fe-
parate the moillure or fulphur, or other volatile mat¬
ters. Four parts of the ore are then to be mixed with
an equal quantity of decrepitated muriate of foda, and
the fame quantity of a mixture of equal parts of iiuor
fpar and lime, with one-half part of charcoal. This
mixture is expofed to a red-heat in a crucible nearly
an hour, after which the iron is found in the metallic
ftate at the bottom of the crucible. In the humid
way, a given quantity of iron ore may be reduced to
powder, and digefted with fix parts of muriatic acid,
wffiich combines with the iron, and other fubftances folu-
ble in that acid, but leaves the fulphur and filiceous
earth behind. The folution is then to be faturated
with potaftr, by wdiich the iron is precipitated in the
ftate of oxide, along with the earths with which it had
combined. The precipitate is to be well dried, and
fubjefled to a red-heat. It is then to be reduced to
powder, and digefted with diluted nitric acid. The
acid combines with the earths, but leaves the iron, be-
caufe it is too highly oxidated to be foluble in this acid.
The oxide, after being well w'afhed, is mixed with
charcoal, and expofed to a ftrong heat in a crucible, by
which the oxygen is driven off, and the iron remains
behind in the metallic ftate.
4. Iron has a peculiar metallic brilliancy. It is of properties.
a grayilh or bluilh-vvhite colour. The fpecific gravity
' - of
Iron, &c.
1.885
Action of
heat.
iS85
Oxidation.
. 18S7
Oxides two
iSSS
Red oxide.
C H E M I
of iron is from 7.6 to 7.89, and according to fome,
even 8.16. It has an aftringent tafte, and when it is
rubbed, gives out a peculiar fmell. One of the fingu-
lar properties of iron, is that of poffefling the magne¬
tic virtue, or of being attrafted by the magnet. Iron
pofleffes a confiderable degree of malleability, but in
this property it is inferior to gold or filvef. It is ex¬
tremely ductile. It may be drawn out into wire ai¬
med as fine as hair. The tenacity of iron is very
great. A wire .078 of an inch in diameter will fupport
a weight, without breaking, equal to more than 500 lib.
avoirdupois *. The texture of iron feems to be fibrous,
and to this, it is fuppofed, are owing its great duc¬
tility and tenacity.
5. Iron is one of the mofl infufible of the metals.
It is faid that it requires a temperature equal to more
than 15o° Wedgwood for its fufion. It becomes red
long before it melts, and different degrees of tempera¬
ture are diftinguithed by the different fhades of red which
it exhibits. The firft is called a dull red, the fecond a
cherry red, the third a bright red, and the fourth a
white heat or incandefcence.
6. When iron is expofed to the air, the furface foon
becomes tarnifhed, and is covered with a brown pow¬
der, w'hich is called rujl. This procefs is greatly pro¬
moted by the moifture of the atmofphere. This is the
oxidation of the metal, and its converfion into an oxide,
by combining with the oxygen of the atmofphere.
The procefs of ruffing, then, is the oxidation of the
iron, and it is owing to the ftrong affinity which ex-
ifts between iron and oxygen. Kut ruff is not merely
a combination of oxygen. It has combined with a cer¬
tain proportion of carbonic acid. I his was formerly
called faffron of mars.
7. There are two oxides of iron ; the firft, or that
which contains the greateft proportion of oxygen, is
common ruff, or, as it is denominated from its colour,
brown or red oxide of iron. I his oxide may be for¬
med by expofing iron filings in an open veffel to a red
heat, and agitating them till they are converted into a
red powder. This oxide confifts of
Oxygen, 48
Iron,
52
100
iGSp
Slack.
The red oxide of iron cannot be decompofed by heat-,
but when it is expofed to heat with its own weight of
iron filings, there is no evolution of any gas, but the
iron filings are converted into a black powder, and the
red oxide is converted into a fimilar powder. This is
the black oxide of iron, which contains the fmaller
proportion of oxygen. 1 his oxide is compofed of
Oxygen,
Iron,
27
73
100
This oxide may alfo be obtained by heating iron fil¬
ings for fome time In ■water at a temperature not un¬
der 70°, or by making the vapour of water pafs through
a red-hot tube containing iron wire, or fmall fragments
of iron. The water in thefe cafes is decompofed, the
hydrogen efcapes in the form of gas, and the oxygen
combines with the iron. This oxide was formerly cal-
Vol. V. Part II.
S T R Y.
led martial ethiops. It is this oxide which is obtained
by burning iron wire in oxygen gas.
8. There is no a£lion between iron and azote. Hy¬
drogen gas, which is obtained from the deeompofition
of water by means of iron filings and fulphuric acid,
holds a fmall quantity of iron in folution. When hy¬
drogen gas is brought into contaiS with the red oxide
of iron ; it deprives it of that proportion of oxygen
which it contains above the black oxide, and converts
it into this oxide. 1890
9. Iron combines very readily with carbone, and Cart>uret-
forms a carburet. When the charcoal combines with
one-tenth of its w-eight of iron, it conftitutes a carburet,
which is found native, and diftinguilhed by the name
of plumbago, or black lead. This compound has a me¬
tallic lullre, is of a bluiffi or dark-gray colour, has a
greafy feel, and ftains the fingers. It is well known as
the fubftance of which black-lead pencils are compofed.
But there is another combination of iron with carbone,
which forms one of the moft important compounds, on
account of its valuable properties, and the numerous
ufes to which it is applied. This is fteel. The dif¬
ferent ftates of iron are owing to its being perfedlly
fiee from contamination with other fubftances, or to its
combination w ith carbone in different proportions. In
thefe different ftates it is diftinguilhed by the names oi
caji or crude iron, wrought iron, and feel. 1S91
Crude or cajl iron. When iron is firft ext rafted Pwcefs fur
from its ores, it is in the ftate of what is called crude obtaimnS
iron. Iron is generally obtained from ores in the ftate
of oxide, and this is frequently mixed with clay. It
muft therefore be feparated from thefe fubftances.
This is accomplifhed by reducing the ore to fmall pieces,
and mixing it with a flux compofed of limeftone and
charcoal. ° It is then expofed to a very ftrong heat.
For this procefs, furnaces are conftrufted in fuch a way',
that the heat can be raifed to a very high temperature.
The nature of this procefs muft be obvious. The car¬
bone of the charcoal combines with the oxygen of the
iron, and forms carbonic acid, which is driven oft in
the ftate of gas. By the ftrong heat to which the lime
and the clay are fubjefted, they are fufed together,
and form a vitreous matter, which being lighter than
the iron, rifes to the furface. The iron alfo is in 3
ftate of fufion at the bottom of the furnace. When
the procefs is finilhed, a hole is opened, through wffiich
the fluid iron flows, and is received into moulds. This
is crude or caff iron, or in the language of the work¬
men, pig iron. In this ftate it is extremely brittle and
hard, and poffeffes fcarcely any malleability. It Hill
contains a confiderable proportion of carbone, and it is
not entirely free from oxygen. xgpZ
Wrought Iron.—The next procefs in the manu-Soft iron,
fafture of iron, is to deprive it of thofe fubftances
which alter its properties, and prevent its application
to the purpofes of pure or malleable iron. 'I he crude
iron is again introduced into a furnace, where it is
melted by the flame of combuftible fubftances, which
is direfted to its furface, and while it is in the ftate of
fufion, it is conftantly ftirred, that the whole of it
may be uniformly brought into contaft with the air.
At laft it fwells, and gives out a blue flame, and when
this is continued for about an hour, the iron begins to
acquire lome confiftency, and at laft becomes foiid.
While it is hot, it is removed from the furnace, and
4. p hammered
666
Iron, $tc
C H E M
*89.3
Natural
fteel.
1894
Of cemen¬
tation.
Caft.
1895
Properties
of fteel.
1897
Diftin-
guiihed
from iron.
Phofphuret
( hammered by the a&ion of machinery. It is then in
the ftate of wrought or foft iron.
'SteeL—This is foft iron or wu'ought iron combined
with a certain portion oi carbone. There are dif¬
ferent precedes for the preparation of Heel} and the
fteel prepared by thefe procetTes has received differ¬
ent names. What is called natural fteel, is prepared
by expofing caft iron to a ftrong heat in a furnace,
while its furface is covered with fcoriae. In this pro-
cefs part of the carbone of the crude iron combines
with the oxygen, from which it is not entirely free,
and is driven off in the ftate of carbonic acid gas!
The iron remains combined with a fmall proportion of
carbone. The fteel prepared in this way is of an in¬
ferior quality.
Steel of cementation is prepared by arranging bar*
of pure iron and charcoal in powder in alternate lay¬
ers, in large troughs or crucibles, which are carefully
doled up with clay. Thefe are expofed to heat in a
furnace for the fpace of eight or ten days, when the
bars of iron are found converted into fteel. This is
fometimes called blijleredJieel from blifters which ap¬
pear on the furface, or tilted fteel, when it is drawn
out into. fmaller bars by the hammer. By breaking
it into pieces, and repeated welding in a furnace, and
afterwards drawing it out into bars, it is converted in¬
to what is called German or [beer Jieel. Steel formed
in this way is generally of a fuperior quality to natural
fteel.
Cojl feel is prepared by fufing natural fteel with
charcoal powder, and pounded glafs, in a clofe cru¬
cible ; or by melting together 30 parts of iron, one of
pounded glafs, and one of charcoal. By this procefs
the beft kind of fteel is obtained, and it is this which
is generally ufed for the finer kinds of cutting inftru-
ments. Different opinions have been entertained con¬
cerning the proportions of iron and carbone in the
compofition of fteel. According to fome, the propor¬
tion of carbone amounts to part, though, according
to others, it does not exceed -j—- part.
Steel poffeffes very different properties from iron.
It is extremely hard and brittle, does not yield to the
file, and retains the magnetic virtue for any length of
time. When it is hammered, its fpecific gravity is
greater than that of iron. It is not malleable when cold
ut it has this property when red-hot, and it may be
reduced to thinner plates than iron.
A-Jhere'1S, \ very. eafy teft by which fteel may be
diftingu.lhed from iron. If a drop of diluted nitric
acid be let fall on fteel, and allowed to remain for a
few minutes, it leaves behind, after it is wafhed off,
a black Ipot which is owing to the converfion of the
caroone of the fteel into charcoal, by combining with
the oxygen of the acid. But if nitric acid is dropt on
iron, a wmitifh gray fpot remains.
• i°. Iron combine's with phofphorus, and forms with
it a phofphuret. It may be formed by melting in a
crucible 16 parts of phofphonc glafs with 16 parts of
iron, and one-half part of charcoal in powder. The
phofphuret of iron is of a white colour when it is
broken and it is obferved cryftallized in fome points
}n tbomboidal pnfms. It is of a ftriated and granu
lated texture and is magnetic. This phofphuret may
be formed alfo, by dropping fmall bits of phofphorus
I s T R Y.
into iron filings heated red-hot. This is the f derite of Iron, See.
Bergman, in which he fuppofed he had diicovered a ’ v—-
new metal, to which he gave the name of Jiderutn. 1899
What is called cold jhort iron, from its being brittle Cold lliort
when cold, but malleable when it is heated, containsiron-
a certain portion of pholphate of iron, to which this
property is owing. It was in the inveftigation of the
nature of this iron, that Bergman obtained, by means
oi fulphuric acid, a white powder, which was convert¬
ed into a brittle metal of a dark-gray colour. By the
experiments of Rdaproth and Scheele it was proved,
that cold fhort iron is a compound of phofphoric acid
and iron.
I. Iron combines with fulphur by different pro- Sulphuret.
ceffes. A fulphuret of iron may be prepared by fuf-
ing together in a crucible, equal parts of powdered
fulphur and iron filings. This is a mafs which is re¬
markably brittle and hard, and of a deep-gray colour.
If this mafs be reduced to powder, and moiftened
w'ith water, the water is decompofed, its oxygen com¬
bines with the fulphur, which is converted into ful¬
phuric acid, and the iron is oxidated. If equal parts
ot fulphur and iron-filings be well mixed together by
trituration, and a fufficient quantity of water be added,
to form the whole into a pafte, and if this mixture be
expofed to the air, it foon becomes hot, fwells up and
cracks, exhaling the vapours of fulphurated hydrogen
gas, and fometimes is fpontaneoufly inflamed. During
this aftion the water is decompofed, the iron is oxi¬
dated, and the fulphur is converted into fulphuric
acid, while the hydrogen of the water combines with
a portion of fulphur, and forms fulphurated hydrogen
gas. By obferving the phenomena of this procefs,
which alfo take place, it is faid when the mixture is
buried under ground, Lemery fuppofed that he could
explain the nature and caufe of volcanic eruptions.
It a mixture of three parts by weight of iron filings,
and one of powdered fulphur, be put into a glafs veffel
on burning coals, a fulphuret of iron is obtained, with
fome remarkable phenomena. It firft melts, and then
all at once becomes red-hot, and fometimes, when
the quantity is confiderable, is accompanied with
an explofion, at the moment when the combination
takes place. According to the experiments of Prouft,
the component parts of lulphuret of iron are,
Sulphur 60
Iron 40
100
According to the experiments of the fame chemift, Pyrites,1
p»yrites, which is found in great abundance in nature,
and ulually cryftallized in cubes, is fulphuret of iron
combined with an additional portion of fulphur. The
component parts of pyrites are
Sulphuret of iron 80
Sulphur 20
12. Iron enters into combination with the acids
and forms falts, and with the metals, and forms alloys/
The affinities of iron and its oxides are, according to Affinities.
Bergman, m the following order.
Iron,
Iron, &c.
Iron.
Nickel,
Cobalt,
Manganefe,
Arfenic,
Copper,
Gold,
Silver,
Tin,
Antimony,
Platina,
Bifmuth,
Lead,
Mercury.
C H E M
Oxide of Iron.
Oxalic acid,
Tartaric,
Camphoric,
Sulphuric,
Saclaftic,
Muriatic,
Nitric,
Phofphoric,
Arfenic,
Fluoric,
Succinic,
Citric,
La&ic,
Acetic,
Boracic,
Pruffic,
Carbonic.
I S T R
iron in this cafe is alfo converted into the red oxide, Iron, Sac.
with the. greater proportion of oxygen. This change,
it is obvious, depends on the ftrong affinity of iron for
oxygen ; for, by the adfion of heat, the fulphate of iron
Oi which the green oxide forms the bafe, is decompo-
fed ; the oxygen of the acid combines with the iron,
and converts it into the red oxide ; part of which, as it
is formed, unites with the acid, before the whole of it is
decompofed j and in this way the produft of this
procefs is the red oxide of iron mixed with red ful¬
phate.
The component parts of this fait are, according toCo^o^
Bergman> tion.
Acid 39
Oxide 23
Water 38
100
I. Salts of Iron.
1. Sulphate of Iron.
Frepara- I* Concentrated fulphuric acid has fcarcely any ac-
«ion. tion on iron. When it is heated, the acid is decom¬
pofed, part of its oxygen combines with the iron, and
Sulphurous acid gas is evolved. But when diluted ful¬
phuric acid is added to iron filings, a violent effervef-
cence takes place, and hydrogen gas is difengaged. In
this procefs, the water, with which the acid is diluted,
is decompofed, the oxygen of which combines with
1004 ‘r0n’ anc* converts it: *nto an oxide, while the hy-
Froperties. drogen efcapes in the ftate of gas. The folution is of
a green colour, and, by evaporation, it affords cryftals
of fulphate of iron, which are tranfparent, of a fine
green colour, in the form of rhomboidal prifms, and
having an acrid, aftringent tafte. This fait almoft al¬
ways reddens vegetable blues. It is very foluble ; two
parts of cold water, and lefs than its weight of boiling
1905 water, are fufficient for its folution.
Found na- 2. This fait is, in many places of the w-orld, a na¬
tive. tural production. It is obtained from the decompofi-
1906 tion of pyrites, which it is fometimes found neceffary
Manufac- to promote by art. This is done by throwing them
Jure. together into heaps, and watering them occafionally.
Sometimes previous roafting is neceffary, either to ren¬
der them more brittle, and to feparate the additional
portion of fulphur above what is neceffary to conftitute
a fulphuret. After a certain time an efflorefcence
takes place, and the furface is covered with the ful¬
phate of iron, which is diffolved in water, concentrated
by boiling, and evaporated, and then allowed to cool
1907 and cryftallize. This fait, which was known to the
Karnes. ancients, was denominated mi/}’, fory, and calchantum.
It is diftinguiffied in commerce by a great variety of
names, as martial vitriol, roman vitriol, and moft com-
1908 monIy by the names of green copperas, or green vitriol.
Adtion of 3- When fulphate of iron is llrongly heated, it melts,
heat. and is deprived of its water of cryfrallization. Sul¬
phurous acid gas is then given out, it affumes a red
colour, and is reduced to the ftate of powder. This
w-as formerly called co/cothar, and colcothar of vitriol.
It is the fait almoft entirely decompofed. Part of the
iron is ftrongly oxidated, and to this the red colour is
owing. It is alfo mixed with fulphate of iron j but the
Thefe.properties vary, according to the eftitoation of
Mr Kirwan, who makes this fait to be compofed of
Acid - 26
Oxide - 28
Water of compofition 8
of cryftallization 38
too
This diftin&ion made by Mr Kirwan between the wa¬
ter of compofition and that of cryftallization is, that the
former is combined with the oxide, and the latter with
the fait.
4. When this fait is expofed to the air, it becomes
of a yellowilh colour, opaque, and a powder forms onair.1UnC’
the furface. The fame thing takes place, if the fait
in folution in water be expofed to the air. From a
fine tranfparent green colour, it becomes turbid, and is
converted into a yellowifh-red liquid, and there is pre¬
cipitated a powder of the fame colour. This change is
owing to the abforption of oxygen, and the converfion
of the green oxide with the fmaller proportion of oxy¬
gen, into the red oxide with the greater proportion.
This procefs is greatly promoted by the direft combi¬
nation of oxygen, or by the addition of thofe fubftances
which are readily decompofed, and give out their oxy¬
gen. When oxymuriatic acid is added to the folutio'n,
it becomes inftantly yellow-, and there is formed a red
precipitate. The fame change takes place when the
fait is diffolved in w-ater impregnated with carbonic
acid.. The iron decompofes the acid, and combines
w-i.th its oxygen. Thus it appears, that the decompo-
fition of the fulphate of iron is owing, in all thefe cafes,
to the abforption of oxygen, and to the higher degree
of oxidation of the metal.
5. The fulphate of iron is converted into the redn 1511 r
fulphate by means of nitric acid. It is decompofed
by the .alkaline earths and the alkalies, which precipi¬
tate it. in the form of oxide. The pure fixed alkalies
and lime .feparate an oxide of a deep green colour,
which,, being expofed to the air, is converted into the
red oxide. Ammonia affords a precipitate of a deeper
green colour. The fulphurets and hydrofulphurets pre¬
cipitate from the folution of green fulphate of iron, a
black fulphurated or hydrofulphurated oxide. Moft of
the falls decompofe the fulphate of iron. When equal
4 B 2 parts
668
Iron, &C.
I9T2
Prepara¬
tion.
I9i3
Properties.
1914
Aiftion of
pruffiate of
gotafh.
1915
Prepara¬
tion.
C H E M I
parts of nitrate of potafli and fulphate of iron are diddl¬
ed together in a retort, a weak nitric acid at Hr it paffes
over, then a nitrous acid, and at laid a very imall quan¬
tity of fulphurous acid. The muriate of foda is de-
compofed by the fulphate of iron, in confequence of
the difengagement ol iulphuric acid, which ieparates
the muriatic acid from its bafe. Sulphate of foda, com¬
bined with the oxide of iron in the date of a vitreous
mafs, remains in the retort. The hyperoxymuriate of
potadr converts the green fulphate of iron into the red.
This fait is alfo decompofed by the alkaline phofphates,
borates, and carbonates.
Red fulphate of iron—In the detail whkdi has been
given of the properties of the green fulphate of iron,
it appears, that it has a drong affinity for oxygen. The
oxide of the green fulphate contains 27 parts cf oxy¬
gen ; but by abforbing another portion of oxygen, it
is converted into the red oxide, which contains 48 parts
of oxygen. This fait may be obtained by the diredf
combination of the red oxide of iron with concen¬
trated fulphuric acid, with the adidance of heat. The
fait remains in the folution from which the green ful¬
phate of iron has been crydallized. This folution has
been called the mother water of vitriol. The red ful¬
phate of iron is very different in its properties from the
green fulphate. It does not afford cryftals *, it is di-
ftinguifhed by its red colour, and it depofits the oxide
of iron, when brought in contadl with the air, or by
the affion of heat. It deliquefces in the air, and at
lad becomes liquid. It is more foluble in water than
the green fulphate •, and alfo foluble in alcohol, by
which it may be feparated from the green fulphate,
which is not affe&ed by the alcohol. When iron fil¬
ings are added to a folution of red fulphate of iron,
part of the oxide is feparated, another part gives up a
portion of its oxygen to the iron, and is converted into
the green fulphate. The fame effedl is produced, as
M. Proud:, by whom this fubjeft has been greatly elu¬
cidated, obferves, by means of other metals, as mercury,
zinc, and tin. The two fulphates of iron are didin-
guidied by other properties. The infufion of nut-galls
produces no change in the green fulphate of iron,
but gives a fine black precipitate with the red ful¬
phate.
Pruffiate of potafii occafions no change of colour on
the green fulphate of iron, but produces a deep blue
precipitate with the red fulphate, from which it appears
that there are two prufliates of iron, correfponding to
the two oxides. The white pruffiate contains the
green oxide with the fmaller proportion of oxygen ; the
blue pruffiate, the red oxide with the greater propor¬
tion. Another chara&eriftic property is, that the
green fulphate of iron abforbs nitrous gas in confider-
able quantity, and affumes a yellowhh colour •, but no
fuch abforption is eftedled by the red fulphate.
2. Sulphite of Iron.
1. Sulphurous acid is decompofed by iron, and the
portion of fulphur which is feparated, remains in com¬
bination with the fait as it is formed. When liquid
fulphurous acid is added to iron filings, it affumes a
deep yellow colour ; fome hydrogen gas is evolved,
with a production of heat, and the yellow colour foon
changes to a greenilh fliade. Sulphuric or muriatic
acid, added to this folution produces an effervefcence,
S T R Y.
but without any precipitation. It is neceffary to add ^ron,
the acid in confiderable quantity to obtain a precipi- v
tate of fulphur in white powder. Fuming nitrous
acid feparates the fulphur of a yellow colour, and in
the form of a duftile mafs. From thefe fads it ap¬
pears, that the firft portion of acids aCls only on the
fimple fulphite of iron $ but when a greater quantity is
added, the fulphurated fulphite is decompofed, and the
fulphur is depofited. 1916
2. The folution of iron in fulphurous acid expofed properties*
to the air, depofifs a reddiih-yellow powder, and af¬
fords cryffals which are furrounded with this reddifh
powder. By adding water to this mafs, it diffolves
the cryffallized part, and leaves the red powder, which
being diffolved in muriatic acid, gives up its iron, and
depofits fulphur, which is ftill mixed with a little iron. 1917
This precipitate diffolved in water, affords a lulphurat-Sulphura-
ed fulphite of iron, with a imaller quantity ol lulphur ted ful-
than the firft folution. Expofed to the air after thePhlte*
firft precipitate is formed, the lurface is loon covered
with a red pellicle. A red powder is depofited, and
afterwards cryftals of fulphite of iron. f'1918
3. The fulphurated fulphite of iron remains perma-Prop(Ilt:ies/
nent by expofure to the air. Its fimple fulphite ab¬
forbs oxygen. The fulphurated fulphite depofits ful¬
phur by the aClion of the 'acids. I he fulphite gives
out fulphurous acid. The fulphurated lulphite is io-
luble in alcohol •, the fulphite is infoluble.
4. The red fulphate of iron with the greater propor¬
tion of oxygen, does not produce the lame efteAon ful¬
phurous acid, by converting it into lulphuric acid, and
thus to form a fulphate of iron, as the oxide of man-
ganefe, becaufe iron has a ftronger affinity for oxygen I9I9
than fulphurous acid. Thus we have leen, in confe-Strong affi-
quence of the fame affinity of iron for oxygen, that n'ty of iron
it decompofes fulphuric acid, and converts part of itfor 0XySen*
into fulphurous acid, and that it even decompofes ful¬
phurous acid, by leparating its fulphur, which combines
wuth the oxide as it is formed, and conftitutes the ful¬
phurated lulphite of iron. Neither of thefe fulphites
of iron give a black colour with the infufion of nut
galls, nor a blue colour with the pruffiate of potafii,
from which it is inferred that the iron is in its mini¬
mum ftate of oxidation, or in that of a green fulphate
of iron.
3. Nitrate of Iron.
1920
Nitric acid a£ls with great violence on iron ; a great Prepara-
quantity of nitrous gas is difengaged, efpecially whention.
the acid is a little diluted with water. When diluted
acid has been employed, the folution is of a yellowilhpr0pertieS.
green colour, and when it is expofed to the air, it af-
iumes a pale colour, in confequence of the nitrous gas
which it holds in folution, combining with oxygen,
and being converted into nitric acid. When it is ex¬
pofed to the air, or concentrated by evaporation, a pre¬
cipitate of the red oxide of iron is formed, becaufe it
combines wdth another portion of oxygen, and is con¬
verted from the g^een to the red oxide. By means
of the alkalies, the green oxide is precipitated from this
folution. jp22
Red nitrate of iron.—This is the fait formed withprepara-
nitric acid and the red oxide of iron. It is prepared tion.
by expofing the green nitrate of iron to the air, which
abforbing oxygen, is converted into the red nitrate.
C H E M
Iron, &c. If iron be diffoketl in concentrated nitric acid, the iron
—v  is converted into the red oxide, and this combining
I(2, with the undecompofed acid, alfo forms the red nitrate
Properties, of iron. The folution of this fait, which is of a brown
colour, does not crydallize ; when it is evaporated, it
affumes the form of jelly, or depofrts a red powder.
When this fait is heated, the acid is driven oft', and the
Adtionof re^ ox^e remains behind. The red nitrate of iron
nut galls, gives a black colour with the fnfufton of galls, and a
&c. blue precipitate with prufliate of potafti, from which
it appears, that the iron is in its higheft degree of oxi¬
dation. This has been fully demonftrated by an ex¬
periment made by Vauquelin. Concentrated nitric acid
was kept for fome months on black oxide of iron, with¬
out any apparent change. The nitric acid, however,
loft its acidity, and acquired a neutral tafte. The
liquid had affumed a brown colour, and large cryftals,
tranfparent and white, with a flight tinge of violet by
looking through them, were formed. The cryftals
were in fquare prifms, terminated by two lided-ridges.
This fait was extremely deliquefcent, and had a pun¬
gent inky tafte. The folution in water becomes red,
as is alfo the precipitate by means of ammonia and pot-
alh. Prufliate of potafti gives a fine blue precipitate.
4. Muriate of Iron.
1. When iron filings are expofed to muriatic acid
Aftionof gas they foon become black, and are converted into
muriatic the ftate of red oxide. This is owing to the decom-
acid in the pofition of the water which the gas holds in folution.
ftate of gas. qpjie bulk of the gas is increafed by the addition of hy¬
drogen gas, from this decompofition of water. When
the whole of the muriatic acid is abforbed by the iron
in the ftate of oxide ; hydrogen gas only remains in
the veflel in which the procefs has been conduced.
When a little water is added, it aflumes a green co¬
lour, having combined with the muriate of iron in the
liquid ftate.
2. Liquid muriatic acid a&s upon iron in propor-
ciVi V tc t*on to degree of concentration, and the action is
the more violent as it is lefs concentrated. An eft'er-
vefcence takes place, with the difengagement of hydro¬
gen gas. As the iron is oxidated by the decompofition
of the water, it is difiblved in the acid. This folution
is of a pale yellowifh colour, and of a ftrong ftyptic
tafte. When it is evaporated to the confiftence of fy-
rup, it forms on cooling, a vifcid mafs, in which are
found needle-fhaped, deliquefcent cry ftals. When this
folution is expofed to the air, or ftrongly heated, ft
aflumes a brown colour, and depofits oxide of iron.
Rtd muriate of iron.—When the red oxide of iron is
treated with muriatic acid, the acid diflblves the iron,
and forms a folution of a deep brown colour. During
the folution, oxymuriatic acid is formed and given out,
which is owing to the combination of a portion of the
oxygen of the oxide with the muriatic acid. The
oxide thus deprived of a portion of its oxygen, com¬
bines with the muriatic acid, and forms red muriate of
iron. When this folution is evaporated to drynefs, it
affords a yellow coloured mafs, which is deliquefcent in
the air. This fait does not abforb nitrous gas, and it
is converted into muriate of iron by the aflion of ful-
phurated hydrogen gas. W hen it is precipitated by
the alkalies, the oxide is not farther changed by ex-
1 S T R V. 669
pofure to the air. The infufion of nut galls gives a Iron, &c.
black colour, and the prufliate of potalh a blue. "" v
5. Hyperoxymuriate of Iron.
This fait was formed by Mr Chenevix, by directing
a ftream of oxymuriatic acid gas into water, having
red oxide of iron diffufed in it j but its properties
have not been afcertained.
6. Fluate of Iron.
Fluoric acid has a very powerful aflion on iron,
which is owing to the evolution of hydrogen gas, and
the decompofition ot water. The iron is oxidated,
and diffolves in the acid, forming a fluate of iron.
The folution has a ftyptic, metallic tafte, does not
afford cryftals by evaporation, but affumes a gelatinous
form. Evaporated to drynefs it becomes hard and
folid, and when ftrongly heated, the acid is driven
off, and there remains behind the red oxide of iron,
fo that this fait is the red fluate of iron. The red
oxide of iron is alfo foluble in fluoric acid, and com¬
municates to it, according to Scheele, an aluminous
tafte. The fluate of iron is decompofed by fulphuric
acid, and is precipitated by the alkalies and the earths.
7. Borate of Iron.
Boracic acid promotes the oxidation of iron by wa¬
ter very flowly. The borate of iron may be obtained
by precipitating the fulphate of iron by means of the
borate of foda, or borax. The borate ol foda is pre¬
cipitated in the form of a whitifti powder. It is info-
luble in water, but its other properties have not been
afcertained.
8. Phofphate of Iron.
Phofphoric acid combines very flowly with iron, Prep^I_
but after the oxidation of the metal has taken place, tion.
it forms with its oxide an infoluble fait. The phof¬
phate of iron may be prepared by adding a folution of
an alkaline phofphate to a folution of fulphate or nitrate
of iron. The alkali leaves the phofphoric acid, and com¬
bines with the fulphuric or nitric; while the phofphoric
acid combines with the iron, and forms a phofphate of
iron, which is in the ftate of white precipitate. Phof-
phovic acid combines with both oxides of iron, and
conftitutes either a green or a red phofphate. The
red phofphate of iron may be obtained by precipitat¬
ing the red muriate of iron in folution, by means of
phofphate of potalh or foda ; and when this latter fait
is treated with pure fixed alkalies, a brownilh red
powder is precipitated, which is the red phofphate of
iron with excels of bafe. It is nearly infoluble in
acids and in water, but is foluble in the ferum of
blood and the white of an egg, communicating to I52S
them a brown colour. This fait exifts in the blood Colours th
of animals, and to it the red colour of the blood is Wood,
owing.
9. Carbonate of Iron,
Carbonic acid combines readily with the oxide of
iron. This is the cafe when iron rufts in the air, for
in proportion as the oxidation of the iron is effected,
it combines with the carbonic acid of the atmofphere,
and
1929
Ruft.
1930
Prepara¬
tion.
1931
Green ar-
feniate.
C H E M
and forms a carbonate of iron. This acid diflblved in
water, when brought in contact with iron, afts upon
it flowiy 5 and there is difengaged, but without effer-
vefcence, a perceptible odour of hydrogen gas, and
the water acquires in the courfe of a few hours, an
aftringent tafte. When this folution is expofed to the
air, as Bergman obferved, it becomes covered with an
iridefcent pellicle, and is decompofed by lime and the
alkalies. But. the alkaline carbonates have no fuch
effefh This folution of the carbonate of iron converts
the fyrup of violets to a green colour. When it is
evaporated, it depofits the fait in the form of a red-
difli ochre. It is this carbonate of iron which exifts
in mineral waters, to which, for this reafon, the name
of chalybeate has been given to waters. Ruft is a car¬
bonate of iron, mixed with the oxide. Fourcroy
found by diftilling it, that it yielded carbonic acid
gas, and a little water, and there remained black oxide
of iron j and diflilled with muriate of ammonia, it
afforded carbonate of ammonia. The component
parts of this carbonate, according to Bergman, are
Acid
Oxide
24
76
100
10. Arfeniate of Iron.
_ *• When iron is digefted with arfenic acid, it is
diffolved, and towards the end of the' procefs the folu¬
tion affumes the form of a jelly. But if it be con¬
duced in a clofe veffel, no coagulation takes place.
By expofing it to the open air for fome hours, the fur-
face becomes fo folid, that the veffel may be inverted
without any part of it dropping out. The folution which
has not been expofed to the air, affords a precipitate
with potafh, of a greenilb-gray colour, from which
there is,difengaged by heat, arfenious acid, and there
remains behind a red oxide of iron. One part of
iron filings diftilled with four of concrete arfenic acid,
fwell up and inflame 3 the metallic acid is fublimed’
and brown fpots appear on the Tides of the retort!
From this experiment it appears, that the iron has car!
ned off the oxygen from the acid.
2.. Arfenic acid does not precipitate iron from its
Jolutions, but the arfeniates or arfenites form a very fo-
luble precipitate, which becomes yellow or red in con-
taC with the air. This precipitate, which is fufible at
a high temperature, exhales the odour of arfenic when
it is melted, is converted into black fcorite when it is
treated with charcoal, gives out a confiderable quan¬
tity of arfenic, and is reduced to the Bate of black
oxide of iron.
. 3- Arfenic acid combines with both the oxides of
iron. The green arfeniate of iron maybe obtained
by adding a folution of arfeniate of ammonia to a fo¬
lution of fulphite of iron. The arfeniate preci¬
pitates in the form of powder which is infoluble in
water. Ijie component parts of this fait, according
to Chenevix, are, 0
Acid 38
Oxide 43
Water 19
too
I S T R Y.
Red Arfeniate of Iron.—This fait is prepared, either Irdn,8«.
by boiling arfeniate of iron in nitric acid, or by adding '“—y-—-
arfeniate of ammonia to a folution of red fulphate of
iron. It is compofed of
Acid 42.4
Oxide 37.2
Water 20.4
100.0
Botli thefe fa Its have been found native.
11. Tungftate of Iron.
lungffic acid has no great effefi: on iron in the
cold. Iron immerfed in a folution of this acid in mu¬
riatic acid, communicates to it a beautiful blue co¬
lour, which is owing to the decompofition of the tung-
ftic acid, and to its reduftion to the metallic Hate by
means of the iron. I ungttic acid precipitates from
the folution of iron in fulphuric acid, tungflate of iron.
Tungftate of iron exifts native under the name of
wolfram.
12. Molybdate of Iron.
The alkaline molybdates which are foluble, preci¬
pitate iron from its folution in acids, of a brown co¬
lour.
13. Chromate of Iron.
If chromic acid, combined with an alkali, be added
to a folution of the red fulphate of iron, a precipitate
is immediately formed, of a brown colour ; but if an
alkaline chromate be added to the green fulphate of
iron,^ the precipitate is green, becaufe the chromic
acid is deprived of a portion of its oxygen, and is
converted to the ftate of green oxide *.
* Fourcroyt
14. Columbate of Iron. Connaifs.
The columbate of iron is found native, and from p. 21'7!^
the only fpecimen which has yet been difeovered, Mr
Hatchet extra&ed a new metal, which has been de-
feribed under the name of columbium. It is of a
dark-brownifh gray colour, has a vitreous luftre, and
a lamellate^ ftrudiure. According to Mr Hatchet, it
is compofed of
Columbic acid,
Oxide of iron,
77-5
21.0
98.5
15. Acetate of Iron.
* • Acetic acid diflblves iron with effervefcence,
with the evolution of hydrogen gas. The liquid af-tiom^
fumes a reddilh-brown colour, and by evaporation be¬
comes a gelatinous mafs, in which are found long
brown cryftals. This, fait has a fweetifti ftyptic tafte.
It is decompofed by heat, and is deliquefeent in the
air. \\ hen it is heated till it no longer gives out the
odour of vinegar, it lets fall a yellowifti oxide, which
is eafily reduced, and is attra&ed by the magnet.
The alkalies feparate the iron nearly in the ftate of
black oxide. This folution affords a black precipitate
with the infufion of nut-galls, and a blue with the al¬
kaline prufliates.
* 2. The
C H E M
Iron-, Sec. 2. The folutlon of this fait is prepared in the large
1'" "v ' ~ way with old iron and vinegar obtained from grain,
^ T933 or molaffes. They are expofed to the air in large vef-
way*e iar^e fels, and as the fermentation of the liquid goes on, it
is converted into acetic acid, the iron is oxidated, and
diffblved by the acid. This folution is employed in
dyeing and calico-printing.
Green acetate of iron.—This fait has been formed
by dilTolving fulphuret of iron in acetic acid. It af¬
fords cryftals by evaporation, in the form of prifms,
and of a green colour. The tafte is flyptic and fweet-
ilh. It gives a white precipitate with the alkaline
pruffiates, and no change is effe&ed by the infufion of
galls. When the folution of this fait is expofed to the
air, it very readily abferbs oxygen, and is converted
into red acetate of iron *,
16. Oxalate of Iron.
Oxalic acid produces a violent aflion on iron, with
the evolution of hydrogen gas. This folution has a very
ftyptic tafte, and forms by evaporation prifmatic cry¬
ftals of a greenilh yellow colour. When this folution is
expofed to the air, or when it is heated, it aftumes a
red colour, which is owing to the abforption of oxy¬
gen, and its converfion into red oxalate. The oxalate
of iron is compofed of
* Jour.
Roy, Injt,
i. p. 308.
r934
Prepara¬
tion.
I93.i;
Compoii-
fcion.
Acid,
Oxide,
55
45
100
Red oxalate of iron.—Oxalic add precipitates the
red oxide of iron from its folution in fulphuric acid,
and forms an oxalate of iron of a fine red colour.
The red oxalate of iron does not cryftallize, and has
little folubility in water. This has been propofed to
be employed as a pigment. None of the acids diflblve
the oxides of iron more readily than oxalic acid, and
efpecially the gallate of iron. On this account it an-
fvvers well for removing fpots of ink, for which pur-
pofe alfo the acidulous oxalate of potafh, or fait of forrel,
h alfo employed.
ry. Tartrate of Iron.
1. Tartaric acid diflblves iron with effervefcence,
and the evolution of hydrogen gas. The folution be¬
comes of a red colour, and aflumes the form of a ge¬
latinous mafs, but does not cryftallize. This is the
red tartrate of iron.
2. But when tartaric acid is added to the folution
of fulphate of iron, and heat applied, a precipitate is
formed, which is not very foluble, but affords lamel-
lated cryftals. This is the compound of tartaric acid
with the green oxide of iron, for it does not form a
precipitate with the alkaline pruffiates, without the
addition of nitric acid.
18. Tartrate of Potalh and Iron.
This triple fait, which was formerly called chaly-
beated tartar, and tartarifed tinBure of Mars, is pre¬
pared by forming into a pafte with water, fix parts of
iron filings with 16 of tartar in powrder. The mix¬
ture is left at reft for 24 hours \ and being diluted
with ig2 parts of water, is boiled for two hours, when
cryftals are depofited of tartrate of potalh and iron.
I s T r y.
19. Citrate of Iron.
Citric acid a&s upon iron with effervefcence, occa-
fioned by the emiflion of hydrogen gas. The folution
becomes of a brown colour; it depofits, by fpontane-
ous evaporation, fmall cryftals of citrate of iron. By
evaporating with heat, it becomes black as ink, and
duftile while it is hot, but falls to powder, and be¬
comes very black when it is cold. This fait has a ve¬
ry aftringent tafte, and is very foluble in water. It is
eompofed of
Acid,
Oxide,
69.62
3°-38
100.00
The cryftals which wrere obtained by fpontaneous eva¬
poration, rvere probably the green citrate 5 and the
black mafs by the a£lion of heat, is' probably convert¬
ed into the red citrate of iron.
20. Malate of Iron.
Malic acid gives a brown folution by its a&ion on
iron, but it does not cryftallize.
2 i. Gallate of Iron.
It has frequently been mentioned, in deferibing the Gallic3acid
falls of iron, that the infufion of nut-galls, or gallic g‘ves a
acid, produces no precipitate or change of colour, c!:)"
when it is added to falls of iron in folution, of which whh°the
the black or green oxide conftitutes the bafe j but red oxide,
when the acid is added to a folution of a fait of iron,
having the red oxide for its bafe, a black precipitate
is immediately formed. From this it appears, that
the black precipitate can only be obtained from the
red oxide of iron, or it is the gallate of iron in the t
higheft degree of oxidation. Writing ink is a compound Ink,'937
of the folution of gallate of iron and the tanning prin¬
ciple. The important qualities of good ink are, that
it (hall be durable, and have a black colour. On this
fubjeft Profeffor Robifon obferves, in his Notes on Dr
Black’s LeSures, that “ the great art in ink-making
is to have a fuperabundance of aftringent matter tocoun-
teraft the difpofition of the iron to a farther calcina¬
tion, which renders the ‘ink brown. It would be a
great improvement in the manufadhire of writing pa¬
per, if fome aftringent matter could be introduced,
A. little ardent fpirits effedually prevents the fpoiling
of ink by keeping, but makes it fink and fpread.
A good Proportion for Writing-Ink.
Rafped logwood, 10 ounces j
Beft gall-nuts in coarfe powder, 3 ounces ^
Gum arabic in powder, 2 ounces j
Green vitriol, 1 ounce j
Rain water, 2 quarts ;
Cloves in coarfe powder, 1 drachm.
Boil the water with the logwood and gum to one
half; ftrain the hot decodhion into a glazed veffel j
add the galls and cloves $ mix and cover it up.
When nearly cold, add the green vitriol, and ftir
it repeatedly. After fome days, decant or ftrain
the ink into a bottle, to be kept clofe corked in a * WacPs
dark place *, L,£l'
Inlft ***'
CHEMISTRY.
Reaion of
the pale
colour.
* Ann. de
Chlm. xi.
P-3l6-
Ibid, xxiii,
p. 48.
'I Klaproth,
■KJfayi ii.
p. 102.
Tranjl.
1939
Prullian
blue.
Ink is fometimes of a very pale colour when firft
\ifed, but becomes black by expofure to the air. This
is owing to the abforptioo of oxygen. The green
vitriol or fulphate of iron, which is employed in
making ink, has not its bafe fully faturated with
oxygen, or is not in the date of red oxide. It is the
converfion of the green into the red oxide, which takes
place when it is expofed to the air. The ufe of gum
in the compofition of ink is to prevent the precipita¬
tion of the black particles, and alfo, it is fuppofed, to
aft as a varnilh, to defend it from the air, which might
give it a brown colour by farther oxidation.
22. Benzoate of Iron.
Benzoic acid readily diffolves the oxide of iron, and
forms with it yellowifh cryftals, which are fweet to the
ta.fte, efflorefce in the air, and are foluble in water and
in alcohol. Gallic acid produces a black precipitate,
and the prufliates give a blue. It is decompofed by
the alkalies, and by the carbonates of lime and barytes.
The acid is driven off by heat *.
23. Succinate of Iron.
Succinic acid combines with the oxide of iron 5 and
the folution by evaporation, affords fmall radiated cry-
ifals, which are tranfparent and of a brown colour.
This fait is infoluble in water. It may be formed by
adding an alkaline fuccinate to the folutions of iron in
acids.
24. Suberate of Iron.
Suberic acid decompofes the fulphate of iron, and
’produces a deep yellow colour f.
25. Mellate of Iron.
Mellitic acid produces a copious precipitate of an
Ifabella-yellow colour, in the folution of iron in ni¬
tric acid. This precipitate is readily diffolved in mu¬
riatic acid J.
26. Laftate of Iron.
Laftic acid combines with iron, and forms with it a
fait which does not cryftallize. The folution is of a
brown colour.
27. Pruffiate of Iron.
1. Pruffic acid combines with both the oxides of
iron. When the pruffiate of pdtalh is added to a fo¬
lution of the green fulphate or muriate of iron, a white
precipitate is obtained. This fhews, as has been al¬
ready obferved, that the bafe of thefe falts, is in its
lowed: degree of oxidation. It is in the ftate of green
or black oxide. But if the pruffiate of potalh be pour¬
ed into a folution of the red fulphate of iron, a fine
blue precipitate is formed, which is Pruffian blue, or a
pruffiate of iron in the ftate of red oxide.
2. When the white precipitate of iron is expofed to
the air, it gradually abforbs oxygen, and is converted
into the blue pruffiate, or Pruflian blue. On the other
hand, the blue pruffiate may be converted into the
white, by preferving it in a clofe veffel, with plates of
iron or tin. The metallic fubftance deprives the iron
of part of its oxygen, and makes it pafs to the flate of
green oxide; in which ftate, combined with pruffic
.acid, it is colourlefs/ Sulphurated hydrogen gas pro-
2
duces a fimilar effeft, by depriving the iron of its o.xy- Iron,
gen. The nitric and oxymuriatxc acids convert the
white pruffiate into blue, by giving up their oxygen,
which combines with the iron, and forms the red
oxide.
II. Aftion of the Alkalies, See. on Iron.
1940
T. Iron, in the metallic ftate, has a very feeble ac-Affa'lcs*
lion on the alkalies and earths. The alkalies, in their
pure and concentrated ftate, promote the decompofi-
tion of water by means of iron. Hydrogen gas is dif-
engaged, and the metal is converted into the ftate of
black oxide, or martial ethiops ; but there feems to be
no perceptible folution of the oxide of iron, which is
thus formed in the liquid alkalies. r
2. The brown oxides of iron readily combine with Eartjis,.
the earths fufpended in water. This combination has
been long employed on account of its properties of af-
furning a great degree of folidity and hardnefs, as a
cement, and efpecially as a cement or mortar to be
employed under water. Hence volcanic produftiens,
as poutZKolana earths, wdiich contain a confiderable pro¬
portion of oxide of iron, are often employed for this
purpofe. The oxide of iron combines alfo with the
earths by means of fufion, and communicates to them
various ftrades of colour, according to the degree of
oxidation, and the proportion of oxide employed. In
this ftate it is ufed in the fabrication of enamels and
coloured glafs. _ m2
3. The alkaline fulphates are decompofed by iron Sulphates*
at a high temperature. The iron deprives the fulphu-
ric acid of its oxygen, and reduces it to the ftate of
fulphur. Fourcroy heated for an hour in a covered
crucible, one part of fulphate of potafh, with twTo of
iron filings. He obtained a kind of granulated fcoria,
which had fwelled up, and was of a deep green on the
furface. It wras extremely hard, and exhibited in fome
of the internal cavities, {Inning fix-fided plates of black
oxide of iron. It had a hot, acrid tafte. When redu¬
ced to powTder, it exhaled the fetid odour of fulphura-
ted hydrogen gas. It wTas not deliquefeent in the air ;
and diluted with 10 parts of w!ater, it wTas of a deep
green colour. This was a folution of hydrofulphuret
of potafh, holding a fmall quantity of iron in folu¬
tion. Sulphur wTas precipitated by the addition of
acids, with the evolution of fulphurated hydrogen
SaS- . . 1943
4. The nitrates are alfo decompofed by means of iron Nitrates,
heated to rednefs. Two or three parts of nitre, with
one of clean iron filings, well triturated together, and
projefted into a red-hot crucible, give out at each
projeftion a great number of vivid fparks. After the
detonation, a half fufed mafs remains, of a reddifh yel¬
low colour, w'bich, by waffling with water, affords pure
potafti, and there remains an oxide of iron in its high-
eft degree of oxidation. Steel alfo detonates with nitre,
and gives out a very brilliant red flame. Thefe mix¬
tures are employed in artificial fireworks.
5. Some of the muriates are alfo decompofed by Muriates,
iron. The experiment of Scheele in tvhich the muri¬
ate of foda wTas decompofed by means of iron, has al¬
ready been mentioned. The muriate of ammonia is
readily decompofed by iron with the afliftance of heat.
Hydrogen and ammoniacal gafes are difengaged. A
preparation formerly known by the name of martial
ammoniacal
Iron, &c. ammoniacal jlowers, was made with 16 parts of muriate
v of ammonia and one of iron filings. This mixture is
fublimed in two earthen veflels, the one being inverted
over the other. A fmall quantity of the muriate of am¬
monia only is decompofed, and the fait affumes a yel-
lowilh colour, with a fmall portion of muriate of iron.
The muriate of ammonia is alfo decompofed by tritu¬
rating the red oxide of iron with this fait. Am¬
monia is difengaged, and the oxide combines with the
acid.
6. Hyperoxymuriate of potalh produces a violent de¬
tonation with iron. Two parts of this fait with one of
iron filings, detonate ftrongly, and with a vivid red flame,
by percuflion, or even by hidden preffure, or by being
brought in contadl with a burning body.
7. There is no adlion between the fluates, borates,
phofphates, or the carbonates, and iron, in the cold.
III. Alloys.
I* Iron combines with arfenic by fufion, forming a
brittle alloy of a white colour, analogous to the native
compound of arfenic and iron, known by the name of
niifpickel. It is more fufible than iron, and is therefore
employed, on account of its luftre and fine polilh, for
different purpofes to which iron is not applicable.
2. The alloys of iron with tungften, molybdena,
chromium, columbium, titanium, and uranium, are
fcarcely known. With titanium iron affords an alloy
of a gray colour, which is extremely infufible.
3. The alloy of iron and cobalt poffeffes fome of
the properties of fteel. It is extremely hard, its
texture is fine-grained, and it is attracted by the
magnet.
4. Iron combines with nickel, and the affinity be¬
tween thefe metals is fo ftrong, that it is extremely
difficult to deprive nickel entirely of iron.
5. Manganefe is frequently found in combination
with iron, to which it communicates a white colour,
and renders it brittle.
6. Bifmuth forms a brittle alloy with iron. It is
attracted by the magnet, even when the proportion of
bifmuth amounts to three-fourths of the whole. Twenty
parts of iron and one of bifmuth, were broken by a
weight of 151 lb. but four parts of iron and three of
bifmuth only fupported 351b. Thefe were the ex¬
periments of Mufchenbroeck. Gellert has obferved
that the alloy of iron and bifmuth has an inferior fpeci-
fic gravity to the mean.
7. Iron combines readily with antimony by fufion.
An alloy of equal parts of thefe metals is not attrafted
by the magnet, has no duftility, and fcarcely any mal¬
leability. Phis alloy was formerly called tuartial re-
gulus. It is brittle and hard, and has a lefs fpecific
gravity than the mean. Iron has a ftronger affinity for
fulphur than for antimony, for when the fulphuret of
antimony is heated with iron, it is decompofed, and the
iron combines with the fulphur.
8. Iron, it has been long fuppofed, has no aflion on
mercury 5 but by triturating together the amalgam of
zinc and mercury with iron filings, and by adding to
the mixture a folution of iron in muriatic acid, and af¬
terwards by kneading this mixture and heating it, Mr
Aikin obtained an amalgam of iron and mercury, hav¬
ing the metallic luffre *.
9. Zinc forms an alloy with iron, but combines with
Voi. V, Part II.
CHEMISTRY.
1945
Arfenic.
1946
Tungften.
1947
Cobalt.
_ 1948
Nickel.
1949
Manganefe
. 1950
Bifnnith.
1951
Antimony
195a
Mercury.
* Phil.
J\Iag. xiii.
406.
1953
Zinc.
it in very fmall proportion. It has been obferved that
zinc may be applied to the furface of iron by fufion,
fo as to defend it from the adion of the air, and thus to
prevent it from ruffing.
10. Iron combines with difficulty with tin. Berg¬
man made a number of experiments on the alloy of iron
and tin. hie put a quantity of tin into a crucible, and
covered it with iron filings. The crucible was then filled
with charcoal, and clofely covered. He expofed the
apparatus to the heat of a forge for half an hour, and
he always obtained two diftina alloys, correfpond-
ing to the weight of the metals which he had em¬
ployed.
The one was iron combined with a fmall quantity
of tin, and the other tin united to a fmall portion of
iron. Tin alloyed with of iron was very malleable,
might be cut with a knife, had loft a little of its luffre,
and was a little harder. fufible phofphates
it gave a brown glafs, which was lefs fufible ; and by
the addition of nitric acid, it became black, and there
was feparated an infoluble powder. Iron combined
with half its weight of tin, exhibits fome of the pro¬
perties of the latter. It is flightly malleable, cannot
be .cut with a knne, unites with difficulty with mer¬
cury and with the phofphates, and in fufion with the
latter, gives out brilliant {parks, which do not appear
from the iron or tin alone. This inflammation is ftill
more brilliant when the quantity of tin is increafed
to A-1-.
Tin combines with iron, and adheres ftrongly to its
furface, forming a thin covering. This is one of the
moft ufeful combinations of tin, for it renders the iron
fit, for. a great many valuable purpofes, for which,
otherwife, on account of its ftrong tendency to oxida¬
tion or rufting, it would be totally inapplicable. This
is well known by the name of tinplate, or while iron.
The procefs of tinning iron is the following: The
plates of iron being reduced to the proper thicknefs,
are cleaned by means of a weak acid. For this pur-
pofe the furface is firft cleaned with fand,to remove any
ruft that may have formed. They are then immerfed
in water acidulated with a fmall quantity of fulphuric
acid, in which they are kept for 24 hours, and oc-
cafionally agitated. They are then well rubbed with
cloths, that the furface may be perfedly clean. The
tin is fufed in a pot, the furface of which is covered
with an oily or refinous matter, to prevent its oxidation.
The plates of iron are then immerfed in the melted
tin, and are either moved about in the liquid metal, or
are dipped feveral different times. They are then
taken out, and rubbed with faw-duft or bran, to remove
the impurities from the furface.
It is faid by fome chemical writers, that the tin not
only covers the furface, but penetrates the iron complete¬
ly, lo as to give the whole a white colour. This feems
to be quite a miftake, which may be very eafily prov¬
ed by the tell: of experiment. If the furface of a piece
of tin-plate be fcraped with a knife, the metallic par¬
ticles which are at firft feparated, are not attra&ed by
the magnet. As the procefs is continued, fome of the
particles are magnetic, which {hews that they are par¬
ticles of iron, fcraped off, after the coating of tin is
feparated, and this coating may be fo completely re¬
moved, that the whole of the particles are attracted by
the magnet. This perhaps it may be faid, would
4 take
1954
Tin.
. 1935
Tinplate.
I9S6
Proeels of
tinning.
674
CHEMISTRY.
1957
Lead.
Copper,&c. take place, even although the iron were alloyed with
' a certain proportion of tin ; but when the coating of
tin is entirely removed, and the iron is moiftened, it
is foon covered with ruft, in the lame way as if it
never had been combined with a particle of tin.
11. Guyton has (hewn, that an alloy may be form¬
ed of iron and lead, which it was formerly fuppofed
could not be eifefled. By melting together equal
parts of lead and filings of iron, he obtained two le-
parate metallic buttons, of which the lead occupied
the lower part of the crucible, and the iron the upper
part. When thefe were lubjefted to the teft of ex¬
periment, it appeared that the lead contained a imall
proportion of iron, and the iron a fmall proportion of
lead
The ufes of iron are extremely numerous and im¬
portant, but they are io well known, that it is alto¬
gether unneceffary to enumerate them.
* Annul, dt
Cbim. xliii.
48.
. 1958
Hiftory.
1959
Ores.
S960
Analyfis.
Sect. XIX. Of Cofpir and its Combinations.
1. Copper feems to have been known in the re-
moteft periods of antiquity. It is among the firft me¬
tals which was employed by the early nations of the
world 5 and indeed this might have been expefted, as
it is not one of the fcarce metals, is eafily extract¬
ed from its ores, and not difficult to work. The
Egyptians applied it to a great variety of ufes, as it
appears, from the earlieff period of their hiftory. The
Greeks were acquainted with the mode of working
copper, and employed it in many of the arts. It was
the bafis of the celebrated Corinthian metal. The Ro¬
mans knew the ufes of this metal, and it is generally
fuppofed that of it they fabricated the greatefl number
of their utenfils. The alloys which they made with
copper, after the example of the Egyptians and
Greeks, were very numerous, and applied to a great
variety of ufes.
2. Copper exifts in confiderable abundance in na¬
ture^ it is found native, alloyed with other metals,
combined with fulphur, in the date of oxide, and in that
of fait. It is not unfrequently met with in the native
date, fometimes crydallized in an arborefcent form,
and fometimes in more regular figures. Copper exifts
native, alloyed with gold and filver. The moft abund¬
ant ores of copper are the fulphurets, and of thefe
there is a confiderable variety, exhibiting various
colours, and various forms of cryftals. In the date of
oxide, it has been found in Peru, of a greeniflr colour,
mixed with white fand. In the ftate of fait, copper is
combined with the fulphuric and carbonic acids, form¬
ing native fulphates and carbonates of copper. The
latter prefent many varieties, but may chiefly be re¬
ferred to the blue and green carbonates.
3. The extraftion of the ores of copper is to be
conduced according to the nature of the combination
in which they exift. I he following procefs is recom¬
mended for the treatment of the fulphurets of copper.
The ore is firft reduced to powder, and then boiled
•with five paits of concentrated fulphuric acid. The
folution is evaporated to drynefs, and the refiduurn well
waffied with w'arm water, to remove all foluble mat¬
ters. The folution being fufficiently diluted, a plate
of copper is immerfed in it, which precipitates the
filver, and afterwards a plate of iron to precipitate the
copper. It is boiled with the plate of iron, till no Copper,See,
farther precipitate takes place. The copper which is ^
thus obtained, is dried with a gentle heat, fo that it
may not undergo oxidation. If it is fuppoied that the
copper is mixed with iron, the whole may be diflolved
in nitric acid, and the procefs is again repeated by in¬
troducing the plate of iron. In this way it is eafy to
difeover the quantity of copper in the fulphurets of this
metal.
4. Copper is a very brilliant metal, of a fine red Properties,
colour, different from every other metallic fubftance.
The fpecific gravity of copper is 8.584. When it is
hammered, it acquires a greater denfity. It pofieffes
a confiderable degree of hardnefs, and fome elafticity.
It is extremely malleable, and may be reduced to
leaves fo fine that they may be carried about by the
wind. It has alfo a confiderable degree of dudlility,
intermediate, according to Guyton, between tin and
lead. The tenacity of copper is alio very great. A
wire .078 of an inch in diameter, will fupport a weight
wuthout breaking equal to more than 3O0lbs. avoirdu¬
pois. Copper has a peculiarly aftringent and dif-
agreeable tafte. It is extremely deleterious, when
taken internally, to the animal economy, and indeed
may be confidered as a poifon. It is diftinguiffied by
a peculiarly difagreeable odour, which it communi¬
cates to the hands by the flighteft fri&ion. 196a
5. Copper does not melt till the temperature is ele-A(ft10ncf
vated to a red heat, which is about 270 Wedgwood,
or by eftimation 1450° Fahrenheit. When it is rapid¬
ly cooled after fufion, it affumes a granulated and por¬
ous texture, but if it be cooled flowly, it affords cryftals
in quadrangular pyramids, or in odlahedrons, wffiich
proceed from the cube, its primitive form. When the
temperature is raifed beyond what is neceffary for its
fufion, it. is fublimed in the form of vifible fumes. 1963
6. When copper is expofed to the air, efpecially if Oxidation,
it be humid, it is foon deprived of its luftre. It tar-
niffies, becomes of a dull brown colour, which gradu¬
ally deepens, till it is converted into that of the an¬
tique bronze, and at laft is covered with a fhining
green cruft, which is well known under the name of
verdigris. This procefs is the oxidation of the metal
by the abforption of oxygen from the atmofphere 5 and it
is promoted and accelerated, either by being moiftened
with water, or by the water which exifts in the atmofphere.
As this oxide is formed the carbonic acid of the atmo¬
fphere combines with it, fo that it is to be confidered
as a mixture of oxide and carbonate of copper.
7. But when copper is fubjefted to a ftrong heat,
the oxidation proceeds more rapidly. If a plate of
copper be made red-hot in the open air, it lofes its
brilliancy, becomes of a deep brown colour, and the
external layer, which is of this colour, may be de¬
tached from the metal. This is the brown oxide of
copper. This oxide may be obtained by immerfing a
plate of red-hot copper into cold water. The feales
which are formed on the lurface fall off by the fudden
contraflion of the heated copper. This may be re¬
peated till the whole is converted into this oxide.
The copper in this ftate is in the higheft degree of
oxidation. Sometimes it affumes a black, and fome¬
times a green colour, which, according to Prouft, are
owing to the combination of carbonic acid with the
oxide. This oxide of copper may alfo be obtained by
diffolving
CHE M I
Copper,See. diffolving copper in nitric or fulphuric acid, and then
* by precipitating with an alkali, which precipitate is to
be dried, to feparate the water. The component parts
of this oxide are,
Oxygen 25
Copper 75
1964
Black
oxide.
ICO
But copper combines with a fmaller proportion of
oxygen, forming an oxide of an orange colour. If
the black oxide of copper be mixed with lefs than an
equal proportion of metallic copper in fine powder,
triturated in a mortar, and introduced into a clofe
veffel with muriatic acid, the whole of the copper is
diffolved with the emiffion of heat, and the oxide is
precipitated of an orange colour, by means of potafii.
This is the oxide of copper with the fmaller propor-
1965 tion of oyxgen. The component parts of this oxide
Yellow. according to Mr Chenevix, are
Oxygen 11.5
Copper 88.5
* Phil.
*Ttanf
1801,
P- 235‘
1966
Pholphuret
1967
Sulphuret.
1968
Singular
experi-
meat.
100.0 ^
This oxide changes colour the moment it is expofed to
the air, by the abforption of oxygen, for which it has
a very llrong affinity.
8. There is no a&ion between azote, hydrogen, or
carbone, and copper.
9. Phofphorus readily combines with copper, and
'forms with it a phofphuret, which is prepared by fu-
fing equal parts of copper and phofphoric glafs, with
£ of the whole of charcoal in powder. Or, it may be
formed by projefting phofphorus on red-hot copper in a
crucible. The phofphuret of copper is of a whitiffi
gray colour, with a metallic luftre, and of a clofe *
texture. It is much more fufible than copper; it
melts by the aftion of the blow-pipe j the phofphorus
burns with deflagration on the furface, and the copper
remains behind in the ftate of black fcoria. Expofed
to the air, it lofes it brilliancy, blackens, and is con¬
verted into a kind of efflorefcence, which is phofphate
of copper. It is compofed of 20 parts of phofphorus,
and 80 of copper.
10. Copper combines with fulphur by different procef-
fes. If fulphur in powder and filings of copper are mixed
together, and formed into a pafte with a little water,
when they are expofed to the air, the mafs fwells up,
becomes hot, and is converted into a brown matter,
which efflorefees flowly in the air, and is converted in¬
to fulphate of copper. This fulphuret may be alfo
formed by heating together in a crucible, equal parts
of fulphur and copper filings. A deep coloured mafs
is thus obtained, which is brittle, and more fufible than
copper. This fubftance, wffiich is employed in dyeing,
is prepared by ftratifying in a crucible plates of copper
and fulphur. When the whole is melted, it is after¬
wards reduced to powder, and was formerly known by
the name of ars veneris.
A Angular and fplendid experiment w>as firft made
by the fociety of Dutch chemifts at Amfterdam, in the
formation of fulphuret of copper. If three parts of
flowers of fulphur, by weight, and eight parts of
copper filings, be mixed together, introduced into a
glafs matrafs, and then placed upon red-hot coals, the
S T R Y. 675
mixture melts, and afterwards, with a kind of explo-Copper,&'>,
fion, becomes almoft inftantaneoufly red hot. If it be l-T' v
then removed from the fire, it continues hed-hot for
fome time, and is converted into a fulphuret of copper.
The Angular part of this experiment is. that it fucceeds
equally well without the accefs of oxygen j or even it
may be performed, when the mixture is under water.
It feems, therefore, at firfl: fight, to be a cafe of com-
buftion, or apparent combuftion, without oxygen. Va¬
rious opinions have been entertained concerning the
nature of this procefs, and different theories have been
propofed to account for the phenomena, which are tion.
feemingly irreconcileable with the prefent theory of
combuflion. Indeed it was at firfl; held up as an objeflion
to the Lavoifierean theory. It has been explained by
fome, by fuppofing that a fmall quantity of air may have
remained within the apparatus, or mixed with the ma¬
terials j or that the quantity of air neceffary might be
fupplied from the moifture, from which the materials
and the apparatus may not have been fufficiently freed.
But this affords no fatisfaftory explanation, for the
quantity of air or water which could remain wffien the
experiment has been carefully performed, is not fuffici-
ent to furnifh the neceffary portion of air for the fup-
port of fuch a vivid combuftion. Fourcroy confiders
it as a cafe of Ample phofphorefcence, a change or hid¬
den increafe of capacity for caloric, or as merely the
feparation of light, or the converfion of caloric into
light; and in fupport of this opinion he ftates, that
the compound is always fulphuret of copper, which
would not have been the cafe, had real combuftion been
effefted, for then it would have been a fulphate of cop¬
per. But it is explained by others according to the
principles of the theory of combuftion, which has been
given by Gren, and which wre have already detailed,
in treating of heat. According to this theory, the
light exifts in combination with the combuftible, which
in this cafe is the copper. When heat is applied to
the mixture, the fulphur melts, and therefore combines
with a great quantity of caloric $ but, when the ful¬
phur combines with the copper, it returns to the lolid
ftate, and therefore gives out a quantity of caloric.
The light from the metal at the fame time combines
with the caloric, and both appear in the form of fire.
It is at the inftant of combination that the mafs be¬
comes red-hot, in confequence of the fudden extrica¬
tion of heat and light from the two fubftances which
form the compound.
Copper combined with fulphur, is one of the moft Copper py>
common ores of this metal. According to the expe-rites,
riments of Prouft, the natural produflion, known by
the name of copper pyrites, is a fulphuret of copper,
combined with an additional portion of fulphur. It is
diftinguiftied by its bnttlenefs, metallic luftre, and yel¬
low colour.
it. The order of the affinities of copper and its 1971
oxide, is according to Bergman, the following: Affinities.
Copper.
Oxide of Copper.
Gold,
Silver,
Arfenic,
Iron,
Manganefe,
Zinc>
Oxalic acid,
Tartaric,
Muriatic,
Sulphuric,
Saclaflic,
Nitric,
4 Q~2
Copper,
Copper, See.
676
Copper,Sec. Copper.
Antimony,
Platina,
Tin,
Lead,
Nickel,
Bifmuth,
Cobalt,
, . Mercury,
Sulphur,
Phofphorus.
I. Salts
C H E M I
Oxide of Copper.
Arienic,
Phofphoric,
Succinic,
Fluoric,
Citric,
Laflic,
Acetic,
Boracic,
Pruflic,
Carbonic.
of Copper.
I. Sulphate of Copper.
197a
Prepara¬
tion.
1973
Properties.
1974
Compoii-
tion.
I. Sulphuric acid has no adlion on copper in the
cold, but when it is concentrated, and at a boiling
temperature, it is decompofed by the copper, with the
difengagement of fulphurous acid gas. By evaporating
the liquid, and by flow cooling, cryftals of a fine blue
colour are obtained. This fait, which is a fulphate of
copper with excefs of acid, reddens vegetable blues,
has a flrong ftyptic, metallic tafte, and is at the fame
time extremely acrid and cauftic. Its fpecific gravity
is 2.1943. ^ foluble in 4 parts of cold, and in 2
of boiling w’ater. It efflorefees flightly in the air, lofes
its water of cryftallization when it is heated, and is
converted into a bluifli white powder. By increafing
the heat the acid is driven off and the oxide remains
behind. The component parts of this fait are, accord¬
ing to Prouft,
Acid 33
Oxide 32
Water 35
ICO
S T
R Y.
Acid, 18
Oxide, 68
Water, 14
100
1977
Compofi-
tion of.
Copper is reduced to the metallic ftate from its fo-
lutions in acids, by feveral metallic fubftancdfc, as
iron, zinc, tin. If a plate of iron be introduced into
a folution of copper in an acid, the iron is in a fhort
time covered with metallic copper. It is in this way
that copper is obtained from its natural folutions in
water.
2. Sulphite of Copper.
Sulphurous acid has no aftion wdiatever on copper; Prepara-
but the oxide of copper readily combines with thistl0n*
acid. Or, the fulphite of copper may be formed by
adding a folution of fulphite of foda, to a folution of
fulphate of copper. An orange-yellow precipitate is
formed, and fmall cryftals of a greenifti wdrite are de-
pofited. Thefe become deeper coloured by expofure
to the air. Both the yellow precipitate and the green-
ifh white fait have been proved by experiment to be
lulphites of copper. The firft contains a greater pro¬
portion of copper, and therefore has an excefs of Bafe,
to which its colour and infolubility are owing. The
fecond is a faturated fulphite, which is foluble and
cryftallizes. When thefe falts are heated by the
blow-pipe, they melt, blacken, affume a grayilh co¬
lour, and are at laft reduced to the metallic ftate.
By the addition of nitric acid they are converted into
fulphate of copper. By the fulphuric acid the fulphu¬
rous acid is driven off, and there remains behind a
brownifh-coloured matter in the ftate of powder, vrhich
is the oxide of copper mixed with a portion of that
metal in the metallic ftate.
1975
INative,
1976
Sympathe¬
tic ink.
2. This fait is generally found in great abundance in
nature, and is obtained either by evaporating the wjater
which holds it in folution, or by expofing the fulphu-
ret of copper to air and moifture, by which it is con¬
verted into fulphate of copper. This fait is known in
commerce by the names of blue vitriol, blue copperas,
and vitriol of copper.
3. None of the acids have any adfion on the fulphate
of copper. It is decompofed by the alkalies and earths,
and precipitated in the form of a bluilh-gray oxide, which
becomes green when expofed to the air, by abforbing
carbonic acid from the atmofphere. Ammonia decom-
pofes and precipitates the fulphate of copper, and, with
an excefs of alkali, diffolves the oxide, which aflumes
a rich, brilliant bine colour. It is alfo partially de¬
compofed by muriate of ammonia. Equal parts of this
fait and fulphate of copper in a heated folution, appear
of a yellow, colour, but when the folution cools, it is
converted into a green. This folution has been em¬
ployed as a fympathetic ink. Paper moiftened with
it, appears of a yellow colour when it is heated, but in
the cold, the colour entirely difappears.
4. When a fmall quantity of cauftic potafh is added
to a folution of fulphate of copper, a greenifti-colour-
ed precipitate is formed, which is diffufed in the folu¬
tion. This is a fulphate of copper with excefs of bafe
snd, according to Prouft, is compofed of
3. Nitrate of Copper.
1. Nitric acid is decompofed by copper with great Prepara-
rapidity. Nitrous gas is given out in great abun-tion.
dance, the metal is oxidated, and diflblved in the acid.
The folution, which is at firft of a pale blue, affumes
a deep colour, and by flow evaporation yields cryftals
in the form of long parallelopideds. This fait has an
acrid ftyptic tafte, is extremely cauftic, and corrodes
the fkin. It is deliquefeent, and very foluble in wa-
ter. This fait expofed to a heat, even under lOO0, Properties,
melts ; by increafing the heat, the water of cryftalli¬
zation is driven off; it detonates flightly on red-hot
coals, and when mixed with phofphorus, by percuf-
fion. g
2. If a quantity of this dried fait, reduced to pow-vi0ient
der, be fpread on a ftreet of tinfoil, it remains without adtion o»
any a£tion •, but if it be moiftened a little with water, dm
and wrapped up, a violent adlion takes place. The
fait is decompoied, and nitrous gas is difengaged with
a great degree of heat. The tinfoil is burft to pieces,
and fometimes it is even inflamed. In this procefs,
the nitric acid of the nitrate of copper is decompofed,
in confequence of the ftrong affinity of the tin for the
oxygen of the acid. The tin is oxidated, nitrous gas
is given out, and the copper is partly reduced to the
metallic ftate. ipSz
3. The alkalies and earths precipitate the folution Decompofi-
oftioir.
CHEMISTRY.
677
Copper,&c. of nitrate of copper in the form of a bluifh white ox-
s—ide, which becomes green by expofure to the air.
When it is precipitated by means of potafh, if the
potafh predominate, a bulky precipitate is formed, of
a fine blue colour. This precipitate is compofed of
the oxide of copper and water, from which Prouft,
who particularly examined it, has denominated it hy¬
drate of copper. Lime thrown into this folution, has
the property of giving it a deeper (hade of blue. It is
by this procefs that the blue pigment known in com¬
merce by the name of verditer, and which is employed
for painting paper, is prepared.
4. If nitrate of copper be diftilled in a retort, the
fait becomes thick, and forms a green cruft on the
retort. It is then in the ftate of nitrate with ex¬
cels of bafe, or fubnitrate^ which is infoluble in w7a-
ter.
c. The component parts of this fait are, according:
Compofi- tQ proult
lion. ’
Acid, 16
Oxide, 67
Water, 17
Acid 12.5
Oxide 79.0
Water 8.5
100.0
Copper, Sec.
19S8
Compofi-
txon.
3. Muriatic acid alfo forms a fait with the oxide ofwiththe
copper in its loweft degree of oxidation. Prouft ob-orange
tained this fait by mixing falts of copper wnth muriate oxide,
of tin, which latter deprived the copper of a portion
of its oxygen, and afforded a fait of a white colour.
It may be formed alfo by introducing a plate of cop¬
per into a bottle filled wnth muriatic acid. This fait
cryftallizes in tetrahedrons. It may be precipitated,
in the ftate of white pow'der •, by diluting the folution
wuth w'ater, and by repeated wafliings, the orange ox¬
ide of copper is obtained. When it is expofed to the
air, it foon combines with oxygen, and is converted
into muriate of copper wTith the oxide in its maximum
ftate of oxidation. This fait is foluble in ammonia,
and forms with it a colourlefs folution, which, after
being for fome time expofed to the air, affumes a
fine blue colour by the abforption of oxygen.
100
5. Hyperoxymuriate of Copper.
4. Muriate of Copper.
1984
?repara-
•tion.
t9S5
Properties.
1986
Compofi-
tion.
I. Concentrated muriatic acid, with the aid of
heat, a£ts on copper and diffolves it. It produces a
flight effervefcence, with the evolution of hydrogen
gas. The folution is of a fine green colour, by which
it is diftinguifhed from the fulphate and nitrate of
copper. This fait may be formed by the direft com¬
bination of the green oxide of copper with muriatic
acid, a little diluted with water. By evaporation
and flow cooling, cryftals may be obtained in the form
of long fmall needles, or rectangular parallelepipeds,
w'hich are of a fine graft green colour. This fait is
extremely acrid and cauftic ; it melts w'ith a moderate
heat it is deliquefeent in the air, and is foon converted
into a thick liquid like oil. This fait fufes at a mo¬
derate heat, and becomes of a uniform mafs by cool¬
ing. It is not decompofed by fulphuric or nitric acids.
The alkalies precipitate a bluifh wdnte oxide, which
becomes green in the air ; the copper is precipitated
by zinc and iron. The component parts of this fait,
according to Prouft, are,
Acid, 24
Black oxide, 40
Water, 36
100
I9S7
Submuri¬
ate.
This fait is therefore the muriate of copper with the
oxide in the higheft degree of oxidation.
2. This fait, according to the experiments of Prouft,
may be diftilled to drynefs without any change ; but
by increafing the heat, a part of its acid is driven off
in the ftate of oxymuriatic acid, and the copper re¬
mains behind in its loweft ftate of oxidation, and
forms a muriate of copper of a white colour. This
muriate may alfo be obtained by diffolving copper in
nitro-muriatic acid. A greenifh powder appears,
which is a muriate of copper wfith excefs of bafe. The
component parts of this fait are,
The oxide of copper diffufed in water, is diffolved,
when a ftream of oxymuriatic acid gas is diredfed
through it. But the properties of this fait were not
examined by Mr Chenevix, who formed it.
6. Fluate of Copper.
Fluoric acid readily oxidates and diflblves copper j
but the properties of this fait are little known. It
forms a gelatinous folution, and affords by evaporation
cubical cryftals.
7. Borate of Copper.
This fait is moft readily formed by adding a folution
of an alkaline borate to the folution of nitrate or ful¬
phate of copper. A greenifti precipitate is formed,
wrhich has very little folubility in water.
8. Phofphate of Copper.
1999
Phofphoric acid is not decompofed by copper j but Prepara-
when it remains for fome time in co®ta6f with thetion.
metal, it promotes the oxidation, and there is thus for¬
med a phofphate of copper, which has little folubility.
Or it may be obtained by pouring an alkaline phoft
phate into a folution of fulphate or nitrate of copper.
The phofphate of copper is formed, which is almoft in¬
foluble. When it is heated with charcoal in a crucible
it affords a gray phofphuret of copper, which has fome
brilliancy. The component parts of phofphate of copi
per, as they have been afeertained by Mr Chenevix, Ic?l
are> Compofi-
tion,
35‘°
61.5
3'5
100.0
The above oxide is compofed of 49.5 brown oxide, and
12 of wTater.
9. Carbonate
Acid,
Oxide,
Water,
67S
Copper, &c.
C H E M I
9. Carbonate of Copper.
199a
Prepara-
lloiu
1993
Compofi-
tion.
Carbonic acid has no aftion on copper, either in the
gafeous or liquid ftate ; but it is very readily abforbed
by the blue or green oxides of this metal. It may be
formed by adding an alkaline carbonate to any of the
folutions of copper in the other acids. To prepare this
fait of the mod brilliant and uniform colour, it fhould
be precipitated with boiling water, walked carefully,
and the velfel which contains it placed in the fun.
This carbonate of copper is found native, and is known
by the name of malachite. It contains the fame pro¬
portions as the artificial carbonate. Its component
parts are,
Acid 25.0
Brown oxide 69.5
Water 5.5
S T R Y.
ally prepared by expofing plates of copper to the a&ion Copppr.gtc,
of vinegar. The furface of the plates is covered with v—'
this bluilh green powder, which being diffolved in ace¬
tic acid affords a folution of a fine greeniih blue co¬
lour. This folution by evaporation and cooling gives
cryftals of a deep blue colour, and in the form of quad¬
rangular, truncated pyramids. The fpecific gravity is
1.779. This fait has a ftrong difagreeable tafte, and 1996
is poilonous. It efflorefces in the air, and is very folu- Properties,
ble in water. It is decompofed by all the alkalies;
and by means of heat, or by diftillation, it is decom¬
pofed, and gives out acetic acid. This fait, according
to the analyfis of Prouft, is compofed of
Acid and water 61
Oxide 39
ICO 40
100.0
10. Arfeniate of Copper.
This fait may be formed by adding a folution of an
alkaline arfeniate to nitrate of copper j or, by digeft-
ing arfcnic acid on copper. A green folution is ob¬
tained, and the arfeniate of copper is precipitated in
the form of a bluifh-white powder. The arfenite of
potaih added to a folution of fulphate of copper forms
a precipitate of a very rich green, which was propofed
1994 b7 Scheele as a paint, becaufe it is unaltered by the
Scheele’s air, and hence it obtained the name of Scheele's green.
green. It is the arfenite of copper. This fait may be formed
by the following procefs :
Diffolve a quantity of potaih in water, and add
white oxide of arfenic, till the potaih is faturated. Fil¬
ter the liquor, and add gradually a folution of fulphate
of copper while it is hot, ftirring the mixture during
the addition. It is then left at reft for fome time, af¬
ter which the arlenite of copper precipitates in the
form of a beautiful green powder. The precipitate
is to be repeatedly walked with water, and dried. Se¬
veral varieties of the arfeniates of copper have been
defcribed, and analyzed by the Count de Bournon and
Mr Chenevix, and an account of them publilhed in the
Philofophical Tranfadlions for 1801.
II. Tungftate of Copper.
Tungftic acid combines with oxide of copper, or
forms a precipitate when added to a folution of ful¬
phate of copper.
I 2. Molybdate of Copper.
Molybdic acid added to a folution of nitrate of cop¬
per, produces a green precipitate.
13. Chromate of Copper.
This is formed by adding chromic acid to a folu¬
tion of nitrate of copper. A red precipitate is ob¬
tained.
14. Acetate of Copper.
X995 Copper is readily oxidated and diffolved in acetic
Prepara- acid. The folution is aided by heat, and gradually af-
Oon* fumes a green colour. The oxide of copper, which is
thus formed, is the verdegris of commerce. It is ul’u-
15. Oxalate of Copper.
Oxalic acid readily afts upon copper, and forms with
it needle lhaped cryftals of a green colour. It readily
combines with the oxide of copper, and is then in the
ftate of a bluilh green powder, which is little folu-
ble in w7ater. Oxalic acid precipitates the fulphate,
nitrate, and muriate of copper, in the form of a bluilh
gray powder.
16. Tartrate of Copper.
Tartaric acid diffolves copper, ■when expofed to the
air, and at laft converts it into an oxide. It combines
readily with the oxides of copper, and forms with them
a fait of little folubility, and of a green colour. When
this acid is added to the folution of fulphate or muriate
of copper, it forms a tartrate of copper, which appears
after fome time in irregular greeniih cryftals.
17. Tartrate of Potaih and Copper.
This triple fait may be prepared by boiling together
oxide of copper and tartar in water. By evaporating
the folution blue cryftals are obtained, which have a
fweetilh talle. If the fame folution be evaporated to
drynpfs, a bluilh green powder remains behind, which
is employed as a paint by the name of Brunfwick
green. gregh."
18. Citrate of Copper.
Citric acid diffolves the oxide of copper at the boil¬
ing temperature. The folution affords by evaporation,
greeniih coloured cryftals.
19. Benzoate of Copper.
Benzoic acid readily diffolves the oxide of copper.
The folution yields fmall cryftals of a deep green co¬
lour, which have little folubility in water. It is de¬
compofed by the alkalies, the carbonates of lime, and
barytes, and the acid is driven off by heat.
20. Succinate of Copper.
When fuccinic acid is long digelled with copper, it
diffolves a fmall portion, and the folution affords green
cryftals.
21. Suberate of Copper.
When fuberic acid is added to a folution of ni¬
trate
C H E M
Copper,&c. trate of copper, it produces a green colour ) but there
is no precipitate.
22. Mellate of Copper.
When mellitic acid is added to a folution of acetate
of copper it affords a precipitate, and the colour of
verdigris, but it produces no change on muriate of
copper.
23. Laftate of Copper.
La£h’c acid, after digeftion with copper, firft affumes
a blue colour, then changes to a green, and is afterwards
converted into a dark brown. The folution does not
yield cryftals.
24. Pruffiate of Copper.
1998
Prepara- The prufliates of potafli precipitate the falls of cop-
tion. per 0f different colours. The pruffiates obtained from
fulphate, nitrate, and muriate of copper, Mr Hatchet
obferves, are very beautiful ; but the fined and deepeft
colour he obtained from the muriate. He has pro-
pofed the prufliate of copper as a paint ; and on trial
with oil and water, it has been found to anfwer the
purpofe. The method which he recommends for the
preparation of this pigment, is to take green muriate
of copper with 10 parts of diddled or rain water, and
to add prudiate of lime, which he thinks is preferable
to prudiate of potafh, until the whole is precipitated.
The prudiate of copper is then to be w7ell wafhed with
* "Jeur. cold water, and to be dried without heat *.
i. 307. ^ II. Aftion of Alkalies, &c. on Copper.
1999 1. The fixed alkalies in folution in water, digeded
Fixed alka- with copper filings, and allowed to cool, promote the
oxidation of the metal. The liquid affumes a dight
blue colour, as well as the copper, but the adlion of the
air is neceffary for this procefs. It fcarcely fucceeds in
2000 in clofe vefiels.
Ammonia. Liquid ammonia, treated in the fame way, becomes
of a brilliant blue colour, but it diffolves only a very
fmall quantity of the oxide. By the dow evaporation
of this folution, the greated part of the ammonia is fe-
parated in the form of gas ; a very fmall quantity on¬
ly remains combined with the oxide of copper. This
folution, it has been faid, yields tranfparent crydals of a
fine blue colour. The dried mafs affumes a green co¬
lour when it is expofed to the air, as the ammonia is
didipated, and the oxide abforbs carbonic acid. The
green oxide of copper is indantly converted to a blue.
This aftion is promoted by heat, and when the heat is
increafed, azotic gas is difengaged ; the hydrogen of
the ammonia combines with part of the oxygen of the
oxide, and forms watery the oxide becomes of a brown
colour, and the metal is at lad: revived.
2001 2. There is no adlion between the earths and copper,
loured 0* excepting by fufion. With the vitrifiable earths and
the oxides of this metal, a glafs is formed, which is
mod commonly of a fine green colour, with different
fhades of brown or red, according to the degree of
oxidation. The oxides of copper are frequently employ¬
ed to colour glafs, porcelain and pottery,
c 3* Copper feems to have but a feeble affion on mod
of the falls. The fulphates are not decompofed by this
metal, even writh the adidance of heat. When cop¬
per is boiled with the folution of alum, it is oxidated
1 s T R Y.
679
3003
Nitrates.
2004
and partially diffolved, by the excefs of fulphuric acid Copper,&c,
which this fait contains. The fulphate of copper thus
formed, feems to combine in the date of triple fait with
the fulphate of alumina and potafh. It has been ob-
ferved that alumina precipitated from alum, the folu¬
tion of which has been kept for fome time in copper
veffels, is dightly tinged with a blue colour. The ni¬
trates, efpecially the nitrate of potafh, when fufed to-,
gether, give out fparks, but without inflammation or'
detonation. A brown oxide of copper is thus formed,
mixed with potafli. When it is wafhed with water,
the alkali is diffolved, and there remains the pure oxide
of copper, which is often prepared in this way for the
fabrication of enamels.
Muriate of ammonia is decompofed by copper with Muriates,
the afliftance of heat. Hydrogen gas and ammoniacal
gas are difengaged, and there remains behind a muri¬
ate of copper. The folution of muriate of ammonia
alfo aids upon copper, and becomes of a blue colour,
when it is kept in veffels of this mgtal. When muri¬
ate of ammonia is fublimed with about of its weight
of green oxide of copper, a fmall quantity of the muri¬
ate of ammonia is decompofed, and the muriate of cop¬
per which is formed, combines with the undecompofed
fait. This was formerly called cupreous jiowers of fal
ammoniac, or ens veneris. If a quantity of lime water,
with about ^ of its weight of muriate of ammonia, be
kept in a copper veffel for xo or 12 hours, the liquid
affumes a fine blue colour. This was formerly called
celefial %vatcr. In this procefs a fmall quantity of
ammonia is difengaged by the lime, and it diffolves
fome portion of the copper, which communicates a
blue colour to the whole folution. This compound
may alfo be formed, by adding a fmall quantity of cop¬
per filings to a mixture of the folution of muriate of
ammonia and lime water.
4. The phofphates, fluates, borates, and carbonates,
have no other aftion on copper than by means of the
water in which they are diffolved. This aftion is great¬
ly promoted by expofure to the air.
III. Alloys^
1. Copper readily combines with almoft all other
metals, by means of fufion ; and many of the alloys
which are thus formed, are of great importance in the
arts. 200$
2. When copper is combined with arfenic, by melt-Arfemc*
ing them together in a clofe crucible, and covering
the furface with muriate of foda, to prevent oxidation,
a white brittle alloy is formed, which has been called
white totnhac. With a certain proportion of zinc and
tin, this alloy is employed in the fabrication of various
ntenfils.
3. The alloys of copper with tungften, molybdena,
chromium, columbium, titanium, and uranium, are
either altogether unknown, or have not been exa¬
mined. 2005
4. Little is known of the alloy of copper and co-
bait. It is faid that it refembles cobalt itfelf in tex¬
ture and brittlenefs.    
r* r • 1 • 2007
5. Copper forms with nickel a white hard alloy, Nickel,
which has no du&ility, and which is foon altered by
expofure to the air.
6. Copper unites with manganefe, and gives an al- Mangancfe,
loy of a red colour, which is very malleable.
7. Equal
68 o
CHEMISTRY.
2009
Bifmuth.
2011
Mercury.
Copper,See. 7. Equa;l parts of copper and bifmuth, melted to-
v ' gether, form a brittle alloy of a pale red colour.
With one-eighth of bifmuth, the alloy is extremely brit¬
tle, of a very pale red colour, and exhibiting in its
texture nearly cubical fragments. The fpecific gravi¬
ty of this alloy is exaftly the mean of that of the two
metals ; and, as the proportion of bifmuth is increaf-
ed, the tenacity of the alloy is diminilhed.
2,010 g. Copper combines readily with antimony by fu-
y' fion. Equal parts of the two metals conftitute an al¬
loy of a beautiful violet colour, and of a greater fpe¬
cific gravity than the mean. This alloy is remarkable
for its lamellated and fibrous texture. The alchemifts
gave it the name of regulus of Venus. A compound
formed of equal parts of martial regulus and regulus
of Venus, according to an alchemical prefeription, the
furface of which exhibits the appearance of meflies or
cavities, was called Vulcan's net, becaufe it feemed
to envelope iron and copper, which were denominated
Mars and Venus.
9. Copper enters into combination with mercury
with fome difficulty. This alloy may be formed by
triturating very thin plates of copper which have been
rubbed with vinegar or common fait, with mercury ;
or, by triturating copper filings with the folution of
mercury in nitric acid. It is alfo formed by other
proceffes ; but whatever be the procefs, this amalgam
is of a reddilh colour, and fufficiently foft to receive
the moft delicate impreflions when it is a little heated.
It becomes hard by expofure to the air. It is decom-
pofed by heat, and the mercury is feparated.
10. The compound of copper and zinc conftitutes
one of the moft important and ufeful alloys, of all the
combinations of the metals. Mufcbenbroeck has giv¬
en a particular defeription of feveral of thefe alloys.
Equal parts of copper and zinc afforded a metal of a
fine golden yellow, whofe fpecific gravity was 8.047 '•>
one part of copper and half a part of zinc, formed a
compound of a pale golden colour ; one part of cop¬
per and three-fourths of zinc, compofed an alloy of a
golden colour, which yielded to the file ; one part of
copper and one-fourth of zinc, gave a compound of a
finer colour than that of brafs. According to the
proportions of the metals which are employed, the
alloys have received different names. The ufual pro¬
cefs for combining them, is either by fufing copper
with a mixture of calamine, or native carbonate of
zinc and charcoal, or by ftratifying plates of copper
with the fame mixture, and expoiing them to heat.
The well-known compoundj diftinguiftre d by the
name of brafs, is an alloy of copper and zinc. The
proportion of the zinc is about one-fourth of the cop¬
2012
.Zinc.
2013
Brafs.
per. This alloy is of a fine yellow colour, lefs liable Copper,&c.
to tarnifh, and more fufible than the copper. The "v-'11'
denfity of this alloy is one-tenth more than the mean.
It is malleable, and poffeffes confiderable duftility.
A compound applied to a great variety of ornamental
purpofes, and known by the names of Prince Rupert's
metal, prince's metal or pinchbeck, is an alloy of zinc
and copper in the proportion of three parts of the for- . 2CI4
mer to four of the latter. This alloy is lefs malleable Pinchbeck-
than brafs j but has a fine golden colour, which is
pretty permanent, and little affefted by expofure to the
air.
The compound of zinc and copper, called brafs, it
is fuppofed, was well known to the ancients. An ore
of zinc WTas employed in the fabrication of it, although
it does not appear that they were at all acquainted
with zinc as a diftinft metal. “ It is probable,” Pro-
feffor Beckmann obferves, after Pliny, “ that ore con¬
taining zinc, acquired the name of cadmia, becaufe it
firft produced brafs.” “ Ipfe lapis e quo fit Ees, cad¬
mia vocata.” “ When it was afterwards remarked,
that calamine gave to copper a yellow colour, the
fame name was conferred on it alfo. It appears,
however, that it was feldom found by the ancients,
and we muft confider cadmia in general as fignifying
ore that contains zinc. Gold-coloured copper or brafs
was long preferred to pure or common copper, and
thought to be more beautiful the nearer it approached
to the heft aurichalcum (c). Brafs, therefore, was
fuppofed to be a more valuable kind of copper j and
on this account Pliny fays that cadmia was neceffary
for procuring copper, that is, brafs. Copper as well
as brafs was for a great length of time called ees, and
it wras not till a late period, that mineralogifts, in or¬
der to diftinguifti them, gave the name of cuprum to
the former. Pliny fays, that it was good when a large
quantity of cadmia had been added to it, becaufe it
not only rendered the colour more beautiful, but in-
creafed the weight (n) *. * m« -
To difeover the proportions of the two metals in invent, v.
this alloy, Vauquelin diffblved a quantity of brafs in iii. 74.
nitric acid. When the folution is completed, he pre- 2015
cipitates the two metals by means of potafh, which is Brafs ana-
added in large quantity, to diffolve the whole of the1?26*1'
oxide of zinc \ and as the oxide of copper is not fo-
luble by this alkali, it remains in the form of black
powder, which is feparated, walked, and dried. A
fiftieth part of the weight of this precipitate is deduc¬
ed for the oxygen with which it is combined 5 the re¬
mainder gives the weight of copper in the alloy. What
is deficient of the whole weight of the alloy, is the
weight of the zinc f. * Fourcny
11. Copper cf"na,fs:
Cbitn% vi.
         159-
(c) According to Bifhop V atfon, the aurichalcum, or onchalcum of the ancients is to be confidered as the
fame with our brafs. Manchejl. Tranf. ii 47.
(d) Mr Beckmann farther adds, “at firft it was called ees cyprium ; but in courfe of time only ry/r/z/w,
from w rich at le^gtn formed cuprum. It cannot, however, be afeertained at what periods thefe appellations
were common. The epithet cupreus occurs in manuferipts of Pliny and Palladius, but we cannot fay whether
later tranlcribers may not have changed cyprius into cupreus, with which they were perhaps better acquainted.
I he oldeft writer who ufes the word cuprum, is Spartian, wTho fays in the life of Caracalla, cancelli ex cere, vcl
cupro; but may not the laft wmrd have been added to the text as a glofs ? Pliny, book xxxvi. 26. fays, addito
cypreo et mtro, wmich Ifidore, xvi. 15. p. 393, expreffes by the words adjedlo cupro et nilro. Hill, of In¬
vent. iu. 75. .
2
CHEMISTRY.
681
Copper, Stc.
2016
Tin.
iCA’J
For can¬
nons.
201S
Jteli metal.
aoip
Tinning
copper.
IT. Copper combines very readily with tin. This
is a very important alloy in the arts. It is with this
alloy that bron%e, metals for calling flatues and can¬
nons, bell-metal, and metallic mirrors, are formed.
Tin diminilhes the du&ility of copper, and increafes
its tenacity, hardnefs, and fonorous quality. Accord¬
ing to Mufchenbroeck, copper acquires the greateft
folidity with the addition of one part of tin to five or
fix of this metal. By increafing the quantity of tin,
the alloy becomes hard and brittle.
To form the alloy employed for cannons, i 2 parts
of tin are united to too of copper. In fufing the two
metals for this alloy, it is neceffary to Itir or agitate
the mixture, otherwife they remain uncombined.
Bronze, or the metal which is ufed for ftatues, is not
different from that of which cannons are made, ex¬
cepting in the proportion of tin being either more or
lefs, to vary the colour.
The component parts of bell-metal are ufually 75
of copper and 25 of tin, or three of copper and one
of tin. A fmall quantity of other metals is fometimes
dete&ed by analyfis, in fragments of bells that have
been examined, fuch as zinc, antimony, bifmuth, and
even filver. But thefe metals are not confidered as
elfential to the alloy. Bell-metal is of a grayilh white
colour, of a clofe grain, and fo hard as to be fcarcely
touched with the file. It is alfo elaftic and fonorous.
The fpecific gravity is confiderably more than the
mean, and it is more fufible than copper. A mixture
of three parts of tin and one of copper, fufed with a
little arfenious acid, and black flux, gives an alloy of
the colour of fteel, very hard, and fufceptible of a
fine polilh, which is employed in the fabrication of
mirrors for telefcopes. But other proportions, with
the addition of other metals, are employed by different
opticians. Bifmuth, antimony, and filver, are added,
to increafe the refle£ling property of the mirror.
Copper veffels which are employed for the purpofes
of domeftic economy, are apt to be corroded or oxi¬
dated by the fubflances which are boiled or preferved
in them. To defend them from the adlion of thefe
fubftances, and to prevent the terrible accidents which
would otherwife happen to thofe who employ any of
thefe matters as food, the infide of fuch veffels is co¬
vered with a thin coating of tin. This is performed
by the following procefs. The furface to be covered
with tin, is feraped very clean with an iron inftrument,
or it is fcoured with wine lees, or weak nitric acid
and fand. The tin is then applied in two ways ; in
the firfl way, the tin is in a ftate of fufion, and the
furface is covered with fome refinous or oily matter,
to prevent oxidation, in the fame way as in tinning
iron. The furface to be tinned is firft immerfed in a
folution of muriate of ammonia, and dried, and then
dipped into the melted tin. Another method is, to
heat the copper velfel on charcoal, and then to apply
to the infide of it a quantity of tin, which is then
melted ; a little muriate of ammonia being thrown in at
the' fame time in powder. The furface is then rub¬
bed with tow. The muriate of ammonia is employed,
both to clean the furface of the copper, and alfo to
prevent the tin from being oxidated. The coating of
tin which can be applied to copper is extremely thin j
and it cannot by any means be increafed, to bear a
heat greater than that which melts tin. Bayen in his
Vgl. V- Part II.
refearches concerning tin, found, that a veflel nine in- Silver, 8cc.
ches in diameter, and three lines in depth, acquired, —v—
by having its furface covered with tin, only 21 grains
of additional weight.
In ufing veffels thus tinned, care fliould be taken
not to allow acid fubrtances to remain for any length
of time in contaft with them, becaufe the tin would
be corroded, and part of the copper afterwards dif-
folved, which would inevitably aft as a poifon. Pure
tin ought only to be employed, at lead without any
mixture of lead. 2020
12. Copper combines very readily with lead by Lead.
fufion. With an excefs of lead, the alloy is of a gray
colour, is duftile, but brittle when it is hot, on account
of the great difference of fufibility of the lead and
copper. This alloy is employed in the fabrication of
printing types for large letters. According to Savary,
the proportion for this purpofe is 100 parts of lead and
20 or 25 of copper. 2oU
13. Copper combines with iron, but with much Iron,
greater difficulty than with the other metals. As the
proportion of iron is increafed, the alloy becomes of a
darker gray, lofes its duftility, and is more infufible.
The alloy of copper with iron has been fuppofed to
conftitute that variety called hot Jhort iron, which pof-
feffes greater tenacity than other kinds of iron, and on
account of fome peculiar properties is more applicable
to a variety of purpofes. 2022
Next to iron, copper is of the greateft importance,Ufas.
and moft extenfive utility, of all the metals. In the
metallic ftate it is employed for a great variety of in-
ftruments and utenfils j fome of its oxides and falts are
much ufed in painting, dyeing, and enamelling ; and
the alloys, with other metals, efpecially with zinc and
tin, are applied to many valuable purpofes in the arts,
and in domeftic economy. But the ufes of copper in
its different rtates, and in its various combinations, are fo
familiar and well known, that it muft appear quite un-
neceflary to enumerate them.
Sect. XX. Of Silver.
1. Silver has been reckoned among the noble or per- Hiftorj.
feft metals, and has been known from the earlieft ages
of the world. Its fcarcity, beauty, and utility, have
always rendered it an objeft of refearch among man¬
kind, fo that the nature and properties of this metal
have been long ftudied and minutely inveftigated. In the
midft of the rage for the tranfmutation of metals which
for centuries fired the imaginations of the alchemifts,
filver occupied a great (hare of their attention and la¬
bour, with the hope of difeovering the means of con¬
verting the bafer and more abundant metals into this,
which is more highly valued on account of its fcarcity
and durability. When the dawn of fcience commen¬
ced, and its light had diffipated the follies and extra¬
vagancies of tnefe purfuits, the earlier chemifts were
much employed in examining the properties and com¬
binations of filver } nor has it been overlooked or ne-
glefted by the moderns. 2024
2. Silver which is neither in fuch abundance nor fo Ores,
univerfally diffufed as many other metals, exifts in na¬
ture in five different ftates •, in the native ftate; in that
of alloy with other metals, efpecially with antimony j
in that of fulphuret, fulphurated oxide, muriate, and
4r carbonate.
2025
Analyhs.
682 CHE M
Silver, Sec. carbonate. I. Native filver, which is characterized by
its dudility and fpecific gravity, is frequently tarniflred
on the furface, of a gray or blackifh colour, and ap¬
pears under a great variety of forms. In this ftate it
is not perfedfly pure. It is ufually alloyed with a lit¬
tle gold or copper. 2. The alloy of filver and anti¬
mony which is the moft frequent, is diftinguifhed by
its brittlenefs and lamellated llruflure from native fil¬
ver, w'hich it refembles in luftre and colour. It cryf-
tallizes in prifms which are fix-fided and pretty regu¬
lar. 3. The fulphuret of filver which is known to
mineralogifts by the name of vitreous filver ore, is of a
dark gray colour, and has fome metallic luftre. It is
ufually cryftallized in the form of cubes, oflahedrons
■with angular facets, or fometimes in the form of the
dodecahedron. 4. The fulphurated oxide of filver and
antimony. In this ore of filver the fulphur is combin¬
ed with the metal in the ftate of oxide ; in the former,
in the metallic ftate. This ore is called redfilver ore.
It is of a deep red colour, fometimes tranfparent, and
fometimes nearly opake, frequently having the luftre
of fteel on the furface. The primitive form of its
cryftals is the rhomboidal dodecahedron. 3. The muri¬
ate of filver which has been long known to mineralo¬
gifts by the name of corneous filver, is found in irregu¬
lar maffes of a grayifn colour, frequently opake, but
fometimes femitranfparent. It is foft and very fufi-
ble.
3. The analyfis of filver ore varies according to its
nature and combinations. Native filver, after be¬
ing broken down and walked, is rubbed with liquid
mercury, which by ftrong trituration difiblves, and
combines with the filver. This amalgam is fubjefted
to preflure, to feparate the excefs of mercury. It is
then diftilled, and afterwards heated in a crucible, to
volatilize the mercury, and the filver remains pure.
\V hen filver is combined with antimony and fulphur,
the ore is to be ftrongly roafted, to feparate the anti¬
mony or fulphur. It is then melted with a proper
quantity of alkaline flux. The fulphurated oxide of
2026 fiver and antimony may be treated in the fame way.
Silver purl- But by thefe procefles the filver is not in a ftate of
uefla^on11' Pe,rfea Purity- To obtaln Pure> by feparation of
*  ‘' otner metals, as copper or iron, it is fubjeffed to the pro-
cefs called cupellation. This depends on the peculiar
property of lead, when it is oxidated and afterwards
vjtrified, of combining with the metals, and leaving the
filver in a ftate of purity. A fmall flat cup made of
the powder of burnt bones, which has received the
name of cupel, is employed for this purpofe. The fil¬
ver to be purified is included in a plate of lead, ufual¬
ly double the weight of the filver. The cupel is in¬
troduced under a muffle in the middle of the furnace,
.he ufe of the muffle is to increafe the heat, by allow¬
ing the metal to be furrounded on all fides with qoals
and at the fame time preventing the admixture of any
part of the fuel with the fufed matter. The heat is
then to be applied fufficiently great, that every part of
the metal may be in fufion, but not fuch as to fublime
the lead too rapidly. As the procefs advances, the
lead is oxidated and vitrified, and having combined
with all the other metals except the filver, finks into
the porous cupel, and leaves the filver pure. The lead
tUnch is now in the ftate of litharge, is extrafted from
tpe cupel, and applied to the ufual purpofes.
I S T R Y.
4. Silver is of a fine white colour, and great bril- Silver,&c,
liancy. The fpecific gravity is 10.474, and according v——1
to fome, when it is hammered, 10,535, and Sometimes
nearly 1 r. The hardnefs- of filver is intermediate
between iron and gold. The elafticity of filver is con-
fiderable, and it is one of the moft fonorous of the metals.
It poffefies very great dudlility and malleability. It may
be beaten out into leaves fg-oV&o an ^nch thick, and
a grain of filver may be fo extended as to be formed
into a hemifpherical veffel of fufficient capacity to hold
an ounce of water, or to be drawn out into a wire 400
feet in length. The tenacity of filver is very great.
A wire .078 of an inch in diameter, will fupport a
weight of 187 lbs. avoirdupois. ‘
5. Silver is a good condu&or of caloric. Its ex-A&ion of
panfive power is lefs than that of lead and tin, and heat,
greater than that of iron. When it is expofed to a
white heat, it melts. The temperature neceflary to
bring it to fufion has been calculated at the iooo° of
Fahrenheit, but according to Kirwan, it requires a
higher temperature than 28* Wedgwood to melt it,
although at that temperature it continues in a ftate of
fufion. When it is cooled flowly after fufion, it ex¬
hibits fome marks of cryftallization. It alfumes the
form of four-fided pyramids, or of oftahedrons. If
the heat be increafed after the filver is melted, it boils,
and may be reduced to vapour. The furface of melt¬
ed filver is fo extremely brilliant, that it feems to
throw out fparks, which is called corufcation by the
workmen.
8. Silver is a good condu&or of ele&ricity. It hasEieftricity,
no perceptible tafle or fmell. See.
9. Silver is not altered by expofure to the air, al- 2?30
though it is foon tarnifhed, which is owing, as Prouft ^ £br‘
afeertained, to a thin covering of fulphuret of filver,
which is formed by fulphureous vapours to which it is
expofed ; but when it is fubje&ed to a ftrong heat for
a long time, in an open veflel, it combines with the
oxygen of the atmofphere, and is converted into an Oxidation,
oxide. In the experiments of Macquer, the oxidation
of filver was effected by expofing it for 20 times fuc-
ceffively in a crucible, to the ftrong heat of a porce¬
lain furnace. At laft perceptible traces of oxidation
were obferved, and a vitreous matter of an olive co¬
lour was obtained. In other experiments filver being
atfted on by the heat of a burning glafs, was covered
with a white powder, which was afterwards convert¬
ed into a cruft of a green colour. Van Marum
pafied eleftric {hocks through filver wire, which was
inftantly reduced to a kind of powder, with a greenifti
white flame, and the oxide which was formed was dif-
fipated in vapour. The oxide of filver, w hich is form¬
ed by thefh procefles, is of a greenifh or yellow colour.
It is compofed of about ten parts of oxygen, and 90
of filver. The oxide of filver is very eafily reduced,
for the affinity of oxygen for this metal is very feeble.
It is decompofed by the application of heat, and even
when it is expofed to the light. By heating it in
clofe veflels, pure oxygen gas is obtained, and the
metal is converted to the metallic ftate, by melting it
in a crucible.
7. Azote, hydrogen, or carbone, have no a&ion
whatever on filver.
8. Silver combines with phofphorus, forming a Phofphuret,
phofphuret. One part of filver in filings with two of
phofphoric
2°33
Sulphuret.
C H E M I
Silver, See. phofphorlc glafs, and half a part of charcoal, expofed
;v— 1 to heat in a crucible, yielded a phofphuret of lilver
which had acquired one-fourth of its primitive weight
of filver. This phofphuret is of a white colour, brit¬
tle, of a granulated texture, and may be cut with a
knife. By throwing pieces of phofphorus on filver
red hot in a crucible, the metal is inftantly melted,
and the phofphuret which is formed remains at the
bottom. At the moment when the furface becomes
folid, a quantity of phofphorus is thrown out with a
kind of explolion, and the furface of the metal then
exhibits a mamellated appearance. Pelletier, who
firft made this experiment, concludes from it, that fil¬
ver is fufceptible of retaining a greater proportion of
phofphorus in combination with it, when it is in
fufion than in the folid ftate, and that the feparation
of the phofphorus is owing to the hidden contradlion
of the filver. A hundred parts of filver in fufion re¬
tain 25 of phofphorus, but only 15 when it becomes
folid. Phofphorus has the property of reducing the
oxides of filver, and of precipitating them from this
folution in acids, in the metallic form.
9. Sulphur combines readily with filver, both in
the dry and humid way. By ftratifying in a crucible
plates of filver alternately with fulphur, and melting
them rapidly, a deep violet-coloured mafs is obtained,
which is more fufible than filver, brittle, cryftallized,
and has a metallic luftre. It may be cut with a knife,
and has a good deal of refemblance to vitreous ore of
filver. When this fulphuret of filver is expofed to heat
for a confiderable time, the fulphur is gradually diffi-
pated, and the filver remains pure and dudlile. Silver
combines very readily with fulphur, when it is long
expofed to thofe matters which gradually depofit this
fubftance. This effedl is immediately produced, when
filver is brought into contadl uuth fulphurated hydro¬
gen gas, or w’hen it is immerfed in water impregnated
with this gas, as in natural fulphureous waters. It is
owing to,the fame caufe that a filver fpoon is tarniflied
by a boiled egg, and particularly if the egg has begun
to fpoil. Sulphurated hydrogen gas which is exhaled
by the egg, is decompofed, the fulphur combines with
the filver, and forms a thin layer of fulphuret of filver,
■which is of a dark or violet colour. The fame thing
happens, when filver is expofed in places that are much
frequented, as in churches and theatres.
10. Silver forms alloys with moll of the metals,
and falts with the acids. The order of the affinities of
filver and its oxide, as they have been arranged by
Bergman, is the following.
2034
Affinities,
Silver.
Lead,
Copper,
Mercury,
Bifmuth,
Tin,
Gold,
Antimony,
Iron,
Manganefe,
Zinc,
Avfenic,
Nickel,
Platina,
Oxide of Silver.
Muriatic acid,
Oxalic,
Sulphuric,
Sacladlic,
Phofphoric,
Sulphurous,
Nitric,
Arfenic,
Fluoric,
Tartaric,
Citric,
Laflic,
Acetic,
s
1. Sulphuric add has no adlion on filver in the cold, Preparu-
but three or four parts of the concentrated acid, boiledtion'
with one part of filver in filings or fmall pieces, pro¬
duce an effervefcence, with the evolution of fulphurous
acid gas. A white powder is formed, which is entire¬
ly foluble in water acidulated writh fulphuric acid.
With excefs of acid, a folution of fulphate of filver is
obtained, which is colourlefs, very acrid and cauftic. 2036
By evaporation it affords cryftals, which are white and Properties*
brilliant, and in the form of fine prifms or needles.
When the folution is more concentrated, a depofition is
formed as it cools, and then it cryftallizes in large
white, brilliant plates, which feem to be compofed of
compreffed four-fided prifms.
2. This fait is not very foluble in water. When
expofed to heat, it melts and fwells up 5 at a higher tem¬
perature it blackens, gives out fulphurous acid, and
oxygen gas, and is then reduced to the metallic ftate.
It is flowly decompofed by the adlion of light. It is de¬
compofed by phofphorus, and vapour of fulphur in the
cold, and by charcoal at a red heat. It is not altered
by the aftion of the acids, excepting the mur atic.
All the alkalies and the alkaline earths precipitate the
oxide of filver from its folution in fulphuric acid, of a
dark gray or brown colour, and efpecially in contafl
with light. Lime caufes a precipitate of a greenilh-gray 20,^
colour. Ammonia rediffolves the precipitate. Sul- Decompofi.
phate of filver is decompofed by the muriates, phof-fion-
phates, and fluates. The carbonates give a white infolu-
ble precipitate of carbonate of filver. The alkaline ful-
phurets, fulphurated hydrogen gas, and water impregna¬
ted with this gas, decompofe the fulphate of filver, and
form in its folution a black precipitate of fulphuret of
filver ; for the oxide is reduced by the hydrogen, while
the filver combines with the fulphur.
2. Sulphite of Silver.
Sulphurous acid combines readily w-ith the oxide ofprepanu
filver. It affumes the form of fmall Ihining grains, ol tion.
a pearly-white colour. It is not altered by expofure
to light. Sulphurous acid precipitates the folution of
filver in nitric acid, in form of a white powder of ful-
phite of filver. The fame fait is obtained by adding a
folution of fulphite of ammonia to a folution of nitrate
of filver. An excefs of this fulphite redxflblves the
precipitate, and forms a triple fait. This fulphite of
ammonia and filver expofed to the fun’s rays, is foon
covered with a pellicle of filver, and the liquid contains
fulphate of ammonia. Sulphurous acid, aided by the
affinity of ammonia, deprives the oxide of filver of its
oxygen, and is converted into fulphuric acid, which
combines with the ammonia, and forms a fulphate. Sul¬
phite of filver is decompofed by muriate of ammonia,
and the precipitate, which is formed, affumes a black
colour, and is partly reduced. When fulphite of fil- Decompofi.
vtr is expofed to the aftion of the blow-pipe, it gives tion.
4 R 2 eut
T R Y.
Silver.
Sulphur,
Phofphorus.
Oxide of Silver.
Succinic,
Pruffic,
Carbonic.
I. Salts of Silver.
1. Sulphate of Silver.
684 C H E M
Silver, See. out fulpliurous acid, melts into a yellow mafs, and
leaves behind a metallic button of pure filver. This
fait has an acrid metallic tafle ; it is foluble in the cau-
ftic alkalies, and forms with them a triple fait.
2040
Prepara¬
tion.
5041
Properties.
ao42
lunar cau-
ftic.
*043
Action of
heat.
2044
Decom pofi-
tion.
2045
By hydro¬
gen.
2046
And phof-
phorus.
3. Nitrate of Silver.
I. Silver diffblves nitric acid with effervefcence, in
confequence of the evolution of nitrous gas. If the
folution be made in a tall conical veflel, the nitrous
gas, which is difengaged from the bottom, is diffolved
in the acid, and communicates a green colour to the
lower part of the liquid. If the green colour is per¬
manent, or paiTes to a blue, the metal is contaminated
with copper j but if it be mixed with gold, a purple
coloured powder is depofited at the bottom of the
veflel.
Nitric acid diflfolves more than of its weight of
lilver. This folution is nearly colourlefs, very heavy,
and extremely caullic. It colours the Ikin, firft of a
reddifh purple, and then of a deep black. It produces the
the fame effeft on the nails, the hair, and all animal
fubflances. It is employed to dye the hair of a black
colour, but this flrould be done with great caution.
When it is diluted with water, fo as to deprive it of its
caufticity, it has an aftringent bitter tafte. By eva¬
porating the folution till a pellicle is juft formed on
the furface, and by How cooling, it cryftallizes in tranf-
parent, brilliant plates, fometimes of a metallic luftre,
when the liquid has been expofed to the fun during
the cryftallization. Thefe cryftals are not very regu¬
lar. They are fometimes fix-ftded, fometimes fquare,
and fometimes triangular ; but they feem to be compo-
fed of very fine fmall prifms. The tafte is fo extreme¬
ly bitter, that it has been denominated the gall of the
metals. It is not deliquefeent in the air. When ex¬
pofed to the light of the fun, it gradually blackens,
and the filver is reduced. When it is heated in a cru¬
cible, it readily melts into a brown liquid, which fwells
up, as it is deprived of its water of cryftallization $
and in this ftate of fufion, if it be allowed to cool, it
aflfumes the form of a deep gray, or black mafs. When
the nitrate of filver is thus fufed, and caft into fmall
cylindrical moulds, the cylinders thus formed, which
exhibit a radiated frafture, are well known in furgery
by the names of lunar cauflic, or lapis inf emails. This
is generally prepared by evaporating the folution of ni¬
trate of filver to drynefs, without previous cryftalliza¬
tion.
3. When nitrate of filver is heated in a retort, it firft
gives out nitrous gas, then very pure oxygen gas,
which is afterwards mixed with azotic gas. The
filver is reduced at the bottom of the veflels. When
a plate or cryftal of nitrate of filver, well dried, is put
upon burning coals, it produces a brilliant detona¬
tion j the filver is reduced, and adheres to the furface
of the charcoal.
4. The nitrate of filver is very foluble in water, and
in this ftate it may be reduced by hydrogen gas and
phofphorus. By expofing paper or filk moiftened with
a folution of nitrate of filver to hydrogen gas, the pa¬
per or filk is coated with metallic filver, in confequence
of the redu&ion of the fait by the hydrogen, which
has a ftronger affinity for the oxygen than the filver.
The fame effeff takes place, if a cylinder of phofpho-
xus be imraerfed in a folution of nitrate of filver. The
1 s t r Y.
phofphorus combines wdth the oxygen of the oxide, Silver, See.
and the filver is depofited on the lurface of the phof- 1' v"-1 r
phorus in the metallic ftate. The phofphorus may be
feparated from the filver by melting it in boiling wa¬
ter. Thefe experiments were made by Sage and Bouil¬
lon in France, and Mis Fulham in England.
5. A mixture of this fait and phofphorus ftruckDetoniUon-
fmartly with a hammer, produces a violent detonation.
Nine grains of nitrate of filver and three of fulphur
produce no detonation, but only an inflammation of
the fulphur, when they are ftruck with a cold ham¬
mer ; but with a hot hammer, a detonation takes
place, with the reduftion of the filver.
6. Nitrate of filver is decompofed by fulphuric acid,
and forms a precipitate of fulphate of filver, in the
ftate of white powder. It is alfo decompofed by ful-
phurous acid. Muriatic acid produces a copious white
precipitate which is very infoluble, and is depofited
in the form of thick heavy flakes of muriate of fil¬
ver.
7. Nitrate of filver is decompofed by all the alka¬
line and earthy matters. A white precipitate is at firft:
formed, which afterwards paffes to an olive green j
but the carbonates of the alkalies give a white preci¬
pitate which remains unaltered. Ammonia occafions
a fparing precipitate, which is re-diflblved by an ex-
cefs of alkali, when there is formed a triple fait. But
a very peculiar aftion takes place between ammonia
and the oxide of filver, by which both the one and
the other are decompofed with a violent detonation.
This is the celebrated fulminating fiver, which was
difeovered by Berthollet in 1788. It is prepared by
the following procefs. 2q g
A folution of pure filver in nitric acid is precipitat-Fu!mina_
ed by lime water. The precipitate is placed on gray ting filver.
paper, which abforbs the whole of the water and the
nitrate of lime. Pure cauftic ammonia is then added,
which produces an effefl fomewhat fimilar to the flak¬
ing of lime. The ammonia diflblves only- part of this
precipitate. It is left at reft for 10 or 12 hours, when
there is formed on the lurface a fhining pellicle, which
is rediffblved with a new portion of ammonia, but
which does not appear, if a fuflicient quantity of am¬
monia has been added at the firft. The liquid is then
feparated, and the black precipitate found at the bot¬
tom, is put in fmall quantities on feparate papers.
This powder is fulminating fiver, which, even while
it is moift, explodes with great violence, when it is
ftruck with a hard body. When it is dry, it is fuffi-
cient to, touch, or rub it (lightly, to produce an ex-
plofion. If the liquid decanted off this precipitate be
heated in a glafs retort, it effervefees, gives out oxy¬
gen gas, and there are foon formed fmall, brilliant,
opaque cryftals, which have a metallic luftre, and
which fulminate with the flighteft touch, though co¬
vered with liquid, and break with violence the veffels
containing them. In this aftion the moft obvious cir-
cumftance is the tendency of the compound to decom-
pofition. The oxygen of the oxide combines wdth the
hydrogen of the ammonia, and forms water, while
the azote of the ammonia efcapes in the form of gas,
and the filver remains behind in the metallic ftate.
Th6 violence of the explofion is owing to the hidden
expanfion of the azotic gas. The Alining pellicle
which appears on the furface, is part of the filver,
from.
C H E M I
Silver, ate. from which the ammonia has been feparated by the
aflion of the air ; and to have the full effeft, another
portion of ammonia is neceffary to diffolve it. Carbo¬
nate of ammonia diffolves the oxide of filver precipi¬
tated by lime, with effervefcence, and the evolution of
carbonic acid ; but there remains enough of this acid
to form a triple fait, which when dried, is in the form
of a yellow powder, but has no fulminating property.
The preparation of this dangerous powder frequently
fails. A mixture of copper, the abforption of carbo¬
nic acid by the oxide of filver, precipitated by means
of lime, and left too long expofed to the air, and am¬
monia containing a little of this acid, either diminilh
or deftroy its fulminating property.
Action of 7- Many of the falts decompofe the nitrate of fil-
falts. ver. All the fulphates produce a precipitate of ful-
phate of filver in the form of powder. The fame ef-
fe£l is produced by the other falts, and the effedl is
fimilar to that which takes place with the acids of
1050 which they are compofed.
Of metals. 8. Moft metallic fubftances have a ftronger affinity
for oxygen than lilver has ; it is therefore precipitated
from its folution in nitric acid, either partially or en-
tirely deprived of its oxygen, and in the metallic
Mercury, date. In the precipitation which takes place by
means of mercury, the lilver is reduced in an arboref-
cent form, which has long retained the name of ar¬
bor DiaruB. Different precedes have been recom¬
mended to effe£t this decompofition. One part of fil¬
ver, according to Lemery, is diffolved in diluted ni¬
tric acid. The folution is then to be farther diluted
with 20 parts of diftillcd water, and then to add two
parts of mercury. It is faid, that it requires, by this
procefs, about 40 days for the formation of the me¬
tallic tree. Homberg gives a fhorter procefs, which
fucceeds fufficiently w7ell. It conlilts in making an
amalgam in the cold of four parts of filver-leaf and
two of mercury. This amalgam is then to be diffolv¬
ed in a fufficient quantity of nitric acid, and the iolu-
tion to be diluted with 32 times the weight of the me¬
tals of water. By introducing into part of this liquid
a fmall ball of foft amalgam of lilver, the formation
of the tree immediately takes place. It may be form¬
ed alfo by putting a foft amalgam of filver into fix
parts of a folution of nitrate of filver, and four of a
folution of nitrate of mercury. In thefe proceffes
one part of the mercury of the amalgam attra&ed by
that of the folution, and carrying off the oxygen of
the filver, precipitates the latter in the metallic Hate.
The precipitation of the filver is ftill favoured by the
affinivy between it and the portion of undiffolved mer¬
cury, and alfo part of the filver of the amalgam.
All thefe attraflions confpire to effedl the Reparation
of the filver, when it is depofited in prifmatic needles,
which arrange themfelves in an arborefeent form.
9. Silver is precipitated from its folution in nitric
acid, by means of copper. When a plate of copper is
immerfed in this folution, diluted with its weight of
diftilled water, the filver is immediately feparated
in whitiffi gray-coloured flakes. If this precipitate
is feraped off, and well waffied with water, after¬
wards fufed in a crucible, and fubjeiled to the pro-
cejs of cupellation with lead, pure filver may be ob¬
tained.
2052
Arbor di-
ame, or (li¬
ver tree.
2053
-Copper.
S T R Y.
685
4. Muriate of Silver.
Silver, See.
... . , 2054
Muriatic acid has no a£Hon whatever on filver j butprepaia-
by adding muriatic acid to a folution of filver in ful- tion.
phuric or nitric acid, the moment it comes in contaft
with thefe folutions, it decompofes them, carries off
the oxide of the filver, and forms with it a white in-
foluble fait, which is precipitated in a kind of coagu¬
lated ftate. The muriates alfo produce a fimilar preci¬
pitate, and hence it is that the nitrate of filver is em¬
ployed as a re-agent, and a moft delicate teft of muri¬
ates or muriatic acid in mineral waters. The muriate
of filver, which is called corneous Ji/ver or horny Jilver,
is extremely infoluble in water. Expofed to the light,
it becomes brown, violet, and black. By heating it
gently in a matrafs, it melts like tallow7, and w7hen it
becomes folid by cooling, it affumes the form of a fe-
mitranfparent gray fubftance, fimilar to fome kinds of
horn, from which it derived its name of luna cornea,
or horn filver. If it be fufed on a ftone, it is convert¬
ed into a kind of friable matter, cryftallized in beauti¬
ful, brilliant, and as it were metallic needles. When
it is ftrorigly heated in a crucible, it filters through it, 2055
and is loft in the fire. The component parts of this Compofi-
falt are, according to Prouft, fi011*
Acid 18
Oxide 8 2
100
This fait is not decompofed by any of the acids, or by-
the pure alkalies. It is decompofed by the alkaline
carbonates. The muriate of filver is very foluble ia
cauftic liquid ammonia. This folution, which is tranf-
parent and colourlefs, undergoes a remarkable' change
when it is expofed to the air. As the ammonia eva¬
porates in the air, there is formed on the furface a
pellicle which aflumes a brilliant, bluiffi, or iridefeent
colour. This pellicle, which gradually increafes in
thicknefs, deepens in colour, and at laft becomes of
a dirty gray or black, by the contaft of light. The
fubftance thus feparated is the muriate of ammonia,
containing a fmall proportion of the metal reduced.
5. Hyperoxymuriate of Silver.
This fait may be prepared by palling oxymuriatic
acid gas through water having the oxide of filver dif-
fufed in it. It is foluble in two parts of w7arm water,
and cryftallizes in cooling in the form of fmall rhom¬
boids. It is decompofed by muriatic acid, and by ni¬
tric and acetic acids. The muriate of filver remains
behind. Expofed to a moderate heat, it melts, oxy¬
gen gas is given out, and the fait is reduced to the
muriate of filver. With oneffialf its weight of fulphur,
it produces violent detonation, by flight percuffion. It
gives out a white vivid flafh.
6. Fluate of Silver.
Fluoric acid diffolves the oxide of filver, and forms
with it an infoluble fait. It is decompofed by fulphu-
ric acid.
7. Borate of Silver.
Boracic acid combines with the oxide of filver, by
addin n
686
C H E M I S T R Y.
Silver, See, adding a foluble borate to the folution of nitrate of
t —r v ’ ' filver. The whole of the lilver is precipitated in the
form of a white, heavy, infoluble powder.
8. Phofphate of Silver.
Phofphoric acid diflblves the oxide of fdver, and
precipitates it from its folution in nitric acid. The
precipitate is a white, heavy powder $ with confider-
able heat it melts into a kind of greenifh enamel. It
is not foluble in water without an excefs of acid.
When it is heated in a retort with charcoal, it gives
out a little phofphorus, and is reduced, in great part,
. to phofphuret of filver.
9. Carbonate of Silver.
Carbonic acid combines readily with the oxide of
filver. It may be prepared by adding an alkaline car¬
bonate to fulphate or nitrate of filver. The carbonate
of filver is precipitated in the form of a white powder.
This fait, which blackens by the a£lion of light,
readily gives out its carbonic acid by heat.
10. Arfeniate of Silver.
Arfenic acid diflblved in water, and heated with
filver, has no aftion upon it ; but when the water is
evaporated, and the heat is increafed to produce vitri¬
fication, arfenic is fublimed,-and there remains a white
vitreous matter, which contains the filver oxidated,
and is covered with a deep yellow-coloured glafs. By-
heating water on this glafs reduced to powder, the fo¬
lution becomes of a brown red colour; the arfenic
acid is difiblved, and carries with it a little oxide of
filver, which is precipitated by adding muriatic acid.
The brown infoluble powder is fufed at a high tempe¬
rature, and becomes femitranfparent. By continuing
the heat in a crucible, the filver is reduced. Arfenic
acid gives a brown precipitate in the folution of nitrate
of filver.
. Silver, &c
14. Acetate or Silver. *■—- -— ,»
Acetic acid diffblves the oxide of filver. The ace-
tate of filver may be prepared, by adding acetate of ~
potalh to a folution of nitrate of filver. The folution
affords, on cooling, fmall prifmatic cryftals. This fait
is very foluble in water, and has an acrid metallic tafte.
When heated, it fwells up, and is decompofed. The
acid is driven oft, and the oxide remains behind.
15. Oxalate of Silver.
Oxalic acid diflolves a fmall portion of the oxide ofOxalate.
filver, which is precipitated from nitric acid, by means
of potafh ; or, by adding oxalic acid to a folution of
nitrate of filver. A white, thick, infoluble precipitate
is formed, which is oxalate of filver. This fait is foon
changed by the aftion of light. When expofed to the
rays of the fun, it becomes black ; and when it is heat¬
ed in a fpoon, it undergoes a kind of detonation.
16. Tartrate of Silver.
... . , 2060
lartanc acid combines with the oxide of filver, and Tartrate.
forms with it a tartrate of filver, which becomes black
by expofure to the air. This acid has no aftion on fil¬
ver itfelf, nor does it produce a precipitate in the folu¬
tion of nitrate of filver.
17. Tartrate of Potafh and Silver.
When tartar is added to a folution of nitrate of fil¬
ver, there is formed according to Thenard, a triple fait, '
which confifts of tartaric acid, oxide of filver, and pot-
afli.
It is decompofed by the alkalies and alkaline car- * ylnn'dt
bonates, and by the fulphates, and muriates *.
18. Citrate of Silver.
11. Tungftate of Silver.
Tungftic acid does not feem to have any a£Hon on fil¬
ver •, but when added to a folution of nitrate of filver, it
occafions a precipitate in the form of white powder, but
its properties have not been examined.
12. Molybdate of Silver.
2056
Molybdate. Molybdic acid produces a white, flaky precipitate
in a folution of nitrate of filver. Nothing is known of
the properties of this fait.
Cbim.
xxxviii.
p. 36.
Citric acid diflblves the oxide of filver, and forms Citrate,
with it an infoluble fait, which becomes black by be¬
ing expofed to the fun. It has a harlh, ftrong, metal¬
lic tafte. It affords by diftillation,concentrated acid, and
leaves behind the filver reduced in an arborefeent form,
mixed with a little charcoal, at the bottom of the re¬
tort. This fait is decompofed by nitric acid. Its com¬
ponent parts are,
Acid, 36
Oxide of fulphur, 64.
100
13. Chromate of Silver.
19. Malate of Silver.
2063
Chromate. . adding chromate of potafti to a folution of filver
in nitric acid, a precipitate is formed, of a moft beau¬
tiful crimfon red, which the adtion of light changes to
purple. This precipitate, which is the chromate of
filver, is in the ftate of powder. When heated by the
aftion of the blow-pipe, it becomes black, and is re¬
duced in part to the metallic ftate. Reduced to pow¬
der in this ftate, it is ftill of a purple colour; but when
it is heated with the blue flame of a candle diredled by
the blow-pipe, it becomes green, and the filver is fepa-
rated in globules. The chromic acid decompofed by
the hydrogen of the blue flame, paffes to the ftate of
green oxide, and the oxide of filver is reduced.
1
Malic acid added to a folution of nitrate of filver, Malate
produces a precipitate, the nature of which is un¬
known.
20. Benzoate of Silver.
106$
Benzoic acid combines with the oxide of filver, and Benzoate,
forms with it a fait which is foluble in water, is not
deliquefeent in the air. but becomes brown by expofure
to the fur’s rays, and is decompofed by heat ; the acid
being driven off, and the oxide reduced to the metal¬
lic ftate.
21. Succinate of Silver.
Succinic acid has no a&ion on filver, but it combines Succinate,
with
C H E M
Silver,&c with its oxide. The fuccinate of filver cryftallizes in
' thin, oblong prifms, which are arranged in a radiated
form.
2 2. Saccolate of Silver.
aeSj # , . .
Saccolate. Saclaflic acid poured into a folution of nitrate of
filver produces a white precipitate, the nature of which
has not been examined.
II. Adlion of Alkalies, &.c. upon Silver.
Adtionof I. The pure alkalies have no effeft on filver. Its
ammonia oxide is foluble in ammonia; but if this folution be long
on filver. expofed to the light, the ammonia is decompofed, azo¬
tic gas is difengaged, water is formed by the combi¬
nation of the hydrogen of the ammonia and the oxy¬
gen of the oxide, which is reduced to the metallic
ftate.
2. Silver forms no compound with the earths ; but in
the ftate of oxide it combines with fome of them, by
vitrification, and in this ftate it colours glafs and ena¬
mels of a yellow', olive green, or brownifh (hade. For
this purpofe the oxide of filver is employed in the
arts.
3. None of the falts have any aftion on filver. It
is not fenfibly oxidated by the nitrates or hyperoxymu-
xiates. The metals which are more eafily oxidated,
and with which filver is frequently contaminated, are
afted on by thefe faline matters, and in this way it has
been obferved, filver may be refined or purified by
means of nitre.
III. Alloys.
I. There are few metallic fubftances with which fil¬
ver does not enter into combination, and form alloys.
Few of thefe, however, are applied to ufeful purpofes.
Arfenic combines with filver, and forms an alloy, which
is externally of a yellow colour, but internally of a
dark gray. It is brittle ; and, when it is expofed to
heat, the arfenic is fublimed, and the filver remains be-
2 , hind in a ftate of purity.
Cobalt. 2. Cobalt is with difficulty alloyed with filver. When
they are melted together in a crucible, they feparate
from each other, according to their fpecific gravities,
2ogg and each having a fmall proportion of the other.
Bifmuth. 3- Bifmuth combines wdth filver very readily by fu-
fion. The alloy is brittle, lamellated, and of an in¬
termediate colour bettveen bifmuth and antimony. The
fpecific gravity is greater than the mean. The two
metals cannot be feparated, but with difficulty. When
this alloy is expofed to ftrong heat in the open air,
the bifmuth is oxidated, and vitrified at the fame time
that it is partially fublimed, fo that it might be employ¬
ed in pllice of lead for the cupellation of filver ; and in
fome cafes bifmuth is preferred, on account of its more
ao55 rapid oxidation.
Antimony. 4. The alloy of antimony and filver is eafily effedf-
ed by fufion. It is heavier than the mean of the two
metals. This alloy is brittle, and has not been applied
2070 to anyufe*
Mercury. 5- Silver has a ftrong affinity for mercury. An a-
malgam may be formed of thefe twro metals, by fatu-
rating filver leaf, or fine filings of filver, with mercury;
or by adding to filver, while it is red-hot, heated mer¬
cury. The confiftence of this amalgam varies accord¬
ing to the proportion of the two metals. In general
I S T R Y. 6.87
it is white and foft, and the fpecific gravity is greater Gold, &c.
than the mean. It finks to the bottom of liquid mer- ““v*—
cury. Expofed to a moderate heat for fome time, it
(hoots out into a kind of vegetation, like the tree of
Diana ; and', if after fufion, it is allowed to cool (low¬
ly, it cryftallizes in the form of fmall leaves, or in fquare
prifms, terminated by four-fided pyramids. When it
remains long expofed to the air, it becomes harder, and
of a more (olid confiftence. This amalgam is much
employed in gilding. 3071
6. Silver combines readily with zinc, by means of fu- Zinc,
fion, and forms with it a brittle alloy, which has not
been applied to any ufe. 3072
7. Silver combines eafily with tin, and forms an al-Tin.
loy which is extremely brittle. The filver is entirely
deprived of its dudility. This alloy, however, in-
ftead of being ufeful, is confidered as one ol the moft
troublefome in the working of filver, on account
of the hardnefs and brittlenels which it communicates,
and it is found almoft impoflible to feparate them en¬
tirely. , 2073
8. Lead, it has been already obferved, readily com-Lead,
bines with filver by means of fufion. It is employed
for the purification of lead in the prcceis of cupella¬
tion. This alloy is very fufible, refembles lead in co¬
lour, and is lefs fonorous, but not lefs dudile than filver.
Tiie fpecific gravity is greater than the mean. 2074;
9. An alloy of filver and iron in equal proportionsIron*
has nearly the colour of filver. It is harder, has fome
dudility, and is attraded by the magnet. Steel is fol-
dered with filver. Guyton fufed together filver and
iron, and obtained tw'o buttons, which were placed by
the fide of each other, and ftrongly adhering, but fuf-
ficiently diftind. Each of the metals was found to be
alloyed with a fmall proportion of the other. The fil¬
ver renders the iron hard and compad, and the iron
communicates to the filver properties which feem to
render it applicable to many important ufes. 2075
10. Silver combines readily with copper, and forms CoPPerj
with it one of the moft ufeful alloys. This alloy gives
hardnefs to the filver, and the colour of the latter is
not diminiftied, unlefs the quantity of copper is con-
fiderable. Thefe properties render it extremely ufeful
in the fabrication of various utenfils, and efpecially of
money. The denfity of the alloy is lefs than the mean
of the two metals. If 137 parts of filver be alloyed
with 7 of copper, the mean fpecific gravity is 10.301,
but it is only 10,175, which (hews an increaie o( bulk
of-g-V Pai't- This is the alloy of the filver coin of * ^ ^
France *. The ftandard filver, which is employed in
the Britifh filver coin, is compofed of 11 parts of filver n*' 30/
and one of copper. 2076
The ufes of filver are as important and extenfive asUies-
any of the metals, except iron, and efpecially when it
is alloyed with copper ; as it is applied as the medium
of commerce by all civilized nations, and for various
inftruments and utenfils, moft of which are fo familiar
as to require no particular enumeration.
Sect. XXL Of Gold and its Combinations.
2077
1. Gold is fpoken of in the earlieft hiftories of fheHiftory,
world. The peculiar properties of this metal, its fcarcity,
durability, and beauty, have rendered it always an ob¬
ject of purfuit, and have raifed it high in the eftima-
tion
*88 CHE M
'Gold, See, tion of mankind. The alchemifts regarded gold as the
v-"' ' pureif, the fimpleft, the moft perfeft, and very juftly
the moft indeftrmftible of all the metals with which
they were acquainted. Hence it was efteemed the
nobleft and moft perfeft of what they confidered as
perfeft metals, and dignified with the pompous name
of king of the metals. It was the objeft of all their la¬
bours and refearches, to difeover the means of tranf-
muting the bafer and more abundant metals into this
precious metal.
2. Gold is fuppofed to be, next to iron, the moft uni-
2078
Univerfally
fnftfaifaUbUt .Ve.rfally a11 the metals ; but, at the fame time
' 1,1‘ it is found in fuch fmall quantities, that it is one of the
quantities
2079
Extradlion
from its
ores.
20S0
Properties.
fcarceft. It is moft commonly found in the ftate of
fmall grains, mixed with the fand or with the foil, al-
inoft in every part of the woild. Gold is alfo found
imbedded in ftones, efpecially quartz, either in grains,
or cryftals, which are odlahedrons ; and it is probably
from thefe that the grains found in the foil or in the
land of the beds of rivers, have been derived. Gold
is, however, more abundant in the tropical regions of
the earth, where it forms an article of commerce, un¬
der the name of gold dujl. In this ftate it is found in
the rivers of Africa, and exported to Europe. But
although gold is always found in the metallic ftate,
it. is not abfolutely pure. It is generally alloyed
with copper or filver, and fometimes with iron and
mercury.
3. To feparate gold from the metals with which it
is alloyed, the procefs recommended by Bergman may
be employed. It is firft diflolved in nitro-muriatic
acid ; the filver is depofited fpontaneoufly in the form of
muriate of filver, which is infoluble ; the gold is pre¬
cipitated in fine powder by the fulphate of iron 5
the quantity of iron may be afeertained by prufliate
of potafh ; and the copper is feparated by means of iron.
Each of thefe procefles is performed on different por¬
tions of native gold, fo that the quantity of gold, and
the different metals with which it is alloyed, may be
determined. In the large way, the extraftion of gold
*s a very fimple procefs. The auriferous fand of rivers
is firft waftied, to carry off all extraneous matters. It
is triturated in a veffel with water, with 10 or 12 times
its weight of mercury. The water is poured off, and
carries with it the earthy matters. The amalgam is
preffed in Ikins, to feparate the excefs of mercury, and
the folid portion which remains isexpofed to heat inftone-
ware retorts, to drive off the mercury, and the gold re¬
mains behind. To feparate the gold from other me¬
tals, it is fubjefled to the procefs of cupellation, which
has been already deferibed in treating of the purifica¬
tion of filver.
4. Gold is of a reddifii yellow colour. It poffeffes
confiderable luftre, although other metals have this
property in a fuperior degree. Gold, next to platina
1S the heavieft body in nature, having a fpecific gra-
v-ity of J9.3 and 194. It is not very hard, but is ex¬
tremely duftile and malleable. It may be beaten out
into leaves fo thin as to equal part of an inch.
1 lie method of extending gold, which is followed by
the gold beaters, is by hammering a number of thin
rolled plates between Ikins or animal membranes. A An¬
gle grain of gold may be beaten out in this way, fo as to
cover 561 fquare inches. The coating of gold, which
covers wire, is (till thinner. By computation it is found
2 ’
I S T R Y. f / .
from the diameter and length of the wire, and the quan- Gold, &c.
tity of gold employed, that it is only fx of the thicknefs v 
of gold leaf. The tenacity of gold alfo is very confi¬
derable. A gold wire .078 of an inch in diameter will
fupport a weight equal to more than ijolbs. avoirdu¬
pois, without breaking. Gold has no perceptible tafte
or fmell.
5. Gold melts, according to Guyton, at the tempe- *oSr
rature of 3 2° Wedgwood. It has been obferved, thathean °
gold, in the ftate of filings or grains, melts with more
difficulty than in larger maffes j and that the fmall
fragments, even after they are fufed, remain in feparate
globules. To make them run into one mafs, a little
nitre or borax is thrown into the crucible. It has alfo
been obferved, that gold, which has only been fubjed-
ed to the degree of heat neceffary for its fufion, is brit¬
tle after cooling. To preferve its duflility, therefore,
the temperature muft be raifed much higher. It is
brittle alfo, when it is too fuddenly cooled after fu¬
fion. By increafing the temperature while the gold is
in fufion, it feems to become convex on the furface,
and when it cools, it finks, which is aferibed to the
expanfion and contraftion of the metal. When it is
flowly cooled, it cryftallizes in the form of quadrangu¬
lar pyramids, or regular o&ahedrons. If the heat be
continued while it is in perfeft fufion, it feems to be
agitated, and to undergo a kind of ebullition. This
was obferved by Homberg and Macquer, by the ac¬
tion of the burning glafs, or when a fmall globule of
gold was added on by the blow-pipe. According to
Macquer, it rofe in vapour to the height of five or fix
inches, and attached itfelf to the furface of a filver plate,
which it gilded completely.
6. Gold is the moft indeftru&ible, and the leaft al-0f ^ir *
tered of all the metals, by expofure to the air. It 1 ^
preferves its luftre, its brilliancy, and colour, for any
length of time.
1\ 'J*16 ftrongeft heat of a furnace, which has been Oxidation,
applied to gold in fufion, has been found incapable of
producing the fmalleft change, or the leaft tendency
to oxidation ; but, by the aftion of Tfchirnhaufen’s
powerful burning glafs, Homberg having placed fome
gold in the focus, found that it rofe in vapour ; and
that it w-as covered with a violet-coloured vitreous
oxide. This change was at firft aferibed to foreign
bodies, particularly to the charcoal on which the ^old
was placed during the experiment. But Macquer re¬
peated the fame experiments wfith a more powerful
glafs, and obtained the fame refult. The vitrification
after fome time gradually extended, the gold diminilli-
ed, and the fupport was impregnated with a purple co¬
loured matter. The effeft of ele&ricity on gold leaf,B 2?S^ .
placed betw’een two cards, was obferved by Camus incitv
I773- The gold was converted into a violet coloured
powder, which adhered to the paper. This feeming
oxidation w’as regarded by fome as merely a minute
mechanical divifion of the gold ; but this obje&ion has
been removed by the experiments of Van Marum on
the combuftibility of gold by means of the powerful
eleftrical machine at Haerlem. A ftrong eleflrical
fliock was paffed through a golden wire fufpended »
in the air. It kindled, burned with a perceptible
green flame, and was reduced to fine powder wffiich
was diffipated in the air. It was fuppofed by this
philofopher, that the inflammation of gold might be
effefled
2oSS
Yellow ox¬
ide.
C H E M
Gold, See. effected vvitlioat the excefs of oxygen gas, as he found
jt to take place in hydrogen gas and other elaftic fluids,
which are incapable of fupporting comburtion. But
the force of this obje&ion is removed by recollecting,
that all gafes hold in folution a quantity of water, and
2085 that water is very readily decompofed by electricity.
By light- A fimilar oxidation has been obferved to take place
sin&- on the gilding in the infide of houfes, or on the furni¬
ture, which has been flruck wdth lightning. The pur¬
ple oxide of gold thus obtained, contains about five or
fix parts in the hiindred of oxygen. Gold combines
with a greater proportion of oxygen, forming a dif¬
ferent oxide of a yellow colour, but this oxide is in¬
capable of combining with any farther portion of oxy¬
gen. It remains, therefore, unchanged in the air, and
retains for a long time its brilliant rich colour. This
oxide, however, is decompofed by the aftion of heat;
the oxygen is driven off, and the gold remains behind
in the metallic ftate.
When gold is diffolved in nitro-muriatic acid, or in
a mixture of equal parts of nitric and muriatic acids, an
effervefcence takes place, and the folution becomes of
a yellow colour. In this procefs the nitric acid is de¬
compofed, its oxygen combines with the gold, and the
oxide, as it is formed, is diflblved in the muriatic acid.
By adding lime water, a precipitate is formed, which
is the yellow oxide of gold, confifting of eight or ten
parts of oxygen in the ico.
8. There is no action between gold and azote, hy¬
drogen, carbone or fulphur. The oxides of gold, in¬
deed, are readily decompofed by hydrogen.
9. Phofphorus, according to the experiments of Pel¬
letier, combines with gold‘, by heating together in a
crucible a mixture of one part of gold in filings, with
two parts of phofphoric glafs, and one-eighth part of
charcoal. Great part of the phofphorus is feparated
from the acid, and driven ofl", but there remains a fmall
quantity united with the gold, forming a phofphuret of
gold. This phofphuret is whiter and more brittle than
the gold, and has fome appearance of cryftallization. It
may be formed alfo by adding ph^fphorus to gold in a
red heat in a crucible. It becomes pale coloured,
granulated, brittle, and a little more fufible. This
phofphuret contains part of phofphorus. It is de¬
compofed by being kept fome time in fufion ; the phof-
20S8 phorus is driven off in the ftate of vapour, and inflamed.
Affinities. xo. The order of the affinities of gold and its ox¬
ides, as they have been arranged by Bergman, is the
following :
aoSy
Phofpliu-
ret.
Gold.
Mercury,
Copper,
Silver,
Lead,
Bifmuth,
Tin,
Antimony,
Iron,
Platina,
Zinc,
Nickel,
Arfenic,
Cobalt,
Manganefe.
Vol. V. Part IL
Oxide of Gold.
Muriatic acid,
Nitric,
Sulphuric,
Arfenic,
Fluoric,
Tartaric,
Phofphoric,
Pruffic.
1 s T R Y.
II. Salts of Gold.
1. Nitrate of Gold.
689
Gold, &c.
2089
When concentrated nitric acid is feveral times fuc-Prepara-
ceffively poured upon gold, boiled and diltilled to dry-tion-
nefs, the gold is diffolved, and the folution atfumes a
yellow colour. This effetl was firit obferved by
Brandt, in feparating gold and filver, by means of this
acid. But it appears from the obfervation of Deyeux
on the folubility of gold in nitric acid, that the fo¬
lution is more readily effedted in proportion to the
quantity of gas, or nitrous gas, which the acid con¬
tains. According to the experiments and obfervations
of Fourcroy, gold leaf is diflblved in nitric acid, im¬
pregnated with nitrous oxide, and that it is owing to
the nitrous oxide that the gold is oxidated, this oxide
being more eafily decompofed than nitric acid. Thus it
happens that the acid is deprived of its colour as it adls
on the gold, and the folution is more rapidly effedled
in the cold than with heat, becaufe the nitrous gas is
difengaged by heat. The acid which at firft had been
deprived of its colour, by the oxidation of the gold,
as this oxide is diflblved, affumes an orange-yellow co¬
lour, holding in folution the nitrate of gold with excefs 209O
of acid. The nitrate of gold cannot be obtained in Decompo*
cryftals. It is decompofed by heat, or by expofure tole<*ky
the light of the fun. When this folution is filtered, it
leaves on the paper a violet-coloured trace, which is pes.
the oxide of gold. The nitrate of gold is alfo decom-
pofed by the alkalies, or by introducing a plate of
tin or filver into the folution, and the purple oxide is
precipitated in the form of powder. It is alfo decom¬
pofed by muriatic acid, which, at the inftant of combi¬
nation, converts the orange colour to a pure yellow.
2. Muriate of Gold.
2091
1. Muriatic acid has no a£Iion whatever on gold, or Prepara-
on its purple oxide, but gold is immediately oxidated ft011*
and diffolved by oxymuriatic acid $ or if nitric acid be
added to muriatic acid, the folution of gold is imme¬
diately effeded. It is on account of this property that
nitro-muriatic acid was diftinguilhed by the name of
flqi/a regiat becaufe it diflblved gold, which was Ailed
by the alchemifts, the king of the metals. The nature
of this a&ion is obvious. Gold is oxidated with great
difficulty. This is effefted by oxymuriatic acid, which
readily parts with its oxygen, or by the addition of ni¬
tric to the muriatic acid, the former of which is de¬
compofed, giving up its oxygen to the gold, which
being oxidated, is diflblved in the muriatic acid, form- 20p2
ing a muriate of gold. This folution of the muriate Properties,
of gold is of a deep yellow colour, extremely acrid
and cauflic, has a very aftringent, metallic tafte, and
ftains the Ikin of a deep purple colour, which becomes
darker by expofure to the air and the light. It con¬
tinues permanent till the epidermis is renewed. It
produces a fimilar effect on all vegetable and animal
matters, and on marble and filiceous ftones. By eva¬
porating this folution, nitric acid is difengaged, and
cryflals are obtained, in the form of truncated octahe¬
drons, or fmall quadrangular prifms, of a topaz co¬
lour. Thefe cryftals are eafily procured by evaporat¬
ing the folution to one-half, and adding a little al¬
cohol. They affume a red colour by the aCtion of
4 S ftrong
2093
Decompoli-
tion.
2094
By hydro-
geri.
2095
Phofphorus.
2096
Sulphurous
acid.
2097
Soluble in
ether.
2098
Adlioii of
alkalies.
ftrong light. They attraft moifture from the air, and
fpontaneoufly become liquid. By gradually heating
in a retort this folution of gold in nitro-muriatic acid,
there paffes over nitric acid, muriatic acid, which car¬
ries with it a portion of gold, and even reddifh-yellow
cryftals of muriate of gold. To the nitro-muriatic li¬
quid, which is of a high colour, and which rifes during
the diftillation, the alchemitts gave the name of red
lion. By evaporating the folution to drynefs, a dry
muriate of gold is, obtained, which may be reduced by
a ftrong heat, previoully giving out oxygen gas, and
leaving the gold behind in the metallic date.
2. The muriate of gold is very ibluble in water.
It is decompofed by hydrogen gas. If a piece of filk
be moiftened with a folution of muriate of gold, the
fait is decompofed, and the gold, reduced to the metal¬
lic date, attaches itfelf to the filk. Muriate of gold is
alfo decompofed by phofphorus. If a dick of phof¬
phorus be introduced into a faturated folution of muri¬
ate of gold, the fait is decompofed, and the gold be¬
ing reduced to the metallic date, forms a cylindrical
covering to the phofphorus, which may be feparated
by dilfolving the latter in hot water. A fimilar eftea
is produced by burning fulphur, by fulphurated and
phofphorated hydrogen gafes, and by fulphurous acid.
If a folution of muriate of gold be cautioufly added to
fulphurous acid, a fine pellicle of gold appears on the
furface, which is indantly precipitated in the form of
zmall grains. f hefe curious and intereding experi¬
ments were made by Mrs Fulham. It is eafy to fee
the nature of the procefs. All the fubdances which
have been enumerated, have a dronger affinity for oxy¬
gen than gold, lo that the oxide of gold in combina¬
tion with, the acid is decompofed ; the oxygen com¬
bining wuth the hydrogen, for indance, and forming
water, or with the phofphorus or fulphur, and forming
fulphuric or phofphoric acid. The reduaion of muri¬
ate of gold, Mrs Fulham has obferved, does not take
place except in the liquid date, and die fuppofes that
the dccompofition of water is neceflary to produce
this ededl. But the liquid date of the fait, it is fup-
pofed by others, is only neceflary, to expofe it to the
aflion of combudibles in a date of minute divifion, and
that otherwife this theory does not account for the’
phenomena.
3. The muriate of gold is foluble in ether. It
forms with it a folution of a golden-yellow colour
which floats on the top of the fluid. By adding ether
to a folution of gold, and agitating the mixture, as
loon as it is left at red, the two liquids feparate, the
ether rifes to the top, and aflumes a yellow, colour
while the nitro-muriatic acid remains below and be¬
comes white. By this procefs a tinaure of gold or
what was. formerly called potable gold, was prepared.
1 he folution of gold in ether is not permanent. It is
loon reduced to the metallic date, and is fometimes
found cryflalhzed on the furface.
4. 1 he muriate of gold is decompofed by all the
a.K.aues and earths, and is reduced to the date of
yellow oxide This decompofition is effeded {lowly
by the fixed alkalies, and if the alkali be added in fuf
ficient quantity, the precipitate is re-diffolved, and the
liquid aiTumes a reddiffi colour. It is owing to this
folution of the oxide of gold by thefe alkalies, that the
CHEMISTRY.
precipitation is flow and difficult. Triple falts are Gold, &e.
formed, the nature of which is unknown. The oxide y—^
of gold thus precipitated, becomes of a purple colour
by expofure to the light j by the adion of heat it
gives out oxygen gas, and the gold is revived.
1 he mofl Angular precipitate from the muriate ofFultounit-
gold, is that by means of ammonia, which forms the mg1 gold.
cdtleA fulminating gold. It is prepared by
the following procefs. To a folution of gold in nitro-
muriatic acid, and diluted with three or four times its
weight of diftilled water, gradually add pure ammo¬
nia, as long as any precipitate is formed. No excefs
of alkali muft be added, becaufe the precipitate is re-
diflolved. It is then waflied and dried in the air on
paper, and afterwards put into a phial, which fhould
be covered only with a bit of cloth or paper, as the
powder is apt to explode with the flighteft fridion. 2.
Fulminating powder may alfo be obtained, by dif- Another
folving.gold in a folution ©f two parts of nitrate ofprocefe.
ammonia, and one of muriatic acid. The oxygen of
the nitric acid combines with the gold, and forms an
oxide, which is diffolved in a portion of the muriatic
acid ; nitrous gas is difengaged, and there remain in
tiie liquid, muriate of gold, and muriate of ammonia.
By precipitating this folution by means of a fixed al¬
kali, fulminating gold is obtained. The alkali com¬
bines with the muriatic acid of the gold and ammonia,
and the oxide, of. gold uniting with the ammonia*
foims the fulminating gold. The precipitate is wafli-'
e.d and dried as in the former procefs. Bafil Valen¬
tine, who firft defcribed this Angular preparation, had
obferved that it produced detonation equally by means
of heat, by friftion,. and percuflion. When a fmall
quantity of fulminating powder is expofed to heat, it
produces a violent detonation ; or, if it be rubbed
with a hard body, a fimilar effeft takes place. It ex¬
plodes alfo, by being fmartly ftruck with a hammer.
Thefe aftonifhing effeds long excited the attention of
philofophers, but received no fatisfadory explanation,
till the nature of the compofition of this fubftance was
difcovered by modern chemifts. It wms examined by
Scheele and Bergman ; and at laft the theory of its
violent adion was fully developed by Berthollet.
This, compound confifts of the oxide of gold and am¬
monia, and as the oxide performs the part of an acid,
it is fometimes denominated aurate of ammonia. Du-T] 2101
ring the explofion which takes place, whether by the ^
application of heat, or by fridion or percuffion, the
hydrogen of the ammonia combines wnth the oxygen
ot . the oxide of gold, and forms water. This water
being fuddenly railed to the ftate of vapour, and the
azote, the other component part of ammonia, being at
the fame time fuddenly converted into gas, produce
the explofion. 1 he gold is reduced to the metallic
ftate.
T his fubftance may be deprived of its fulminatingMa^bede-
property, by being expofed lor fome time to a verycompofed
gentle heat. It is then converted into a blackifli Wltl10ut
brown powder. A fimilar effed is produced, by fub. exPlolioiu
jeding it for a long time to the temperature of boil¬
ing water. Its fulminating property is at leaft greatly
dimimffied by the latter procefs. It appears too, that
the contad of air promotes this adion ; for when
it was heated in an iron globe, in an experiment
which
CHEMISTRY.
2103
Adlion of
metals.
*104
Purple
powder of
Caflius.
Gold, Stc. which Birch performed before the Royal Society of
  v London, or in a fphere of Itrong copper, in an expe¬
riment by Bergman, no detonation took place. Ber-
thollet applied a gentle heat to a quantity of fulminat-
ing gold, in copper tubes ; and he obtained ammonia-
cal gas, and the gold was reduced to the ftate of pur¬
ple oxide. By thefe experiments it appears, that this
fubftance is decompofed without detonation, when the
ludden dilatation of the gafes which are difengaged is
refilled by firong veffels, or when the heat is fo mo¬
derate as to feparate the ammonia without decompofi-
tion.
5. The muriate of gold is decompofed by almoft
all metallic fubllances. Some metals decompofe it
completely, and reduce it to the metallic ftate, while
others deprive it of a portion of oxygen, and reduce
it to the ftate of purple oxide. Bifmuth, zinc, iron,
copper, and mercury, reduce the gold to the metallic
ftate. Lead, filver, and tin, occafion a precipitate in
the form pf pqrple oxide. The molt Angular of all
thefe precipitates, and which has long occupied the
attention of chemifts, is that which is produced by
means of tin. This is called the purple precipitate, or
powder of CaJJius. It was at firft particularly defcrib-
ed by Caflius, from whom it derived its name 5 but it
was known long before, even fo early as the time of
Bafil Valentine, by whom it is mentioned. If a plate
of tin be immerfed in a folution of muriate of gold,
the furface of the metal is foon covered with a deep-
coloured violet or purple powder, which is gradually
diffufed through the whole liquid. This is ufually
prepared by adding to a folution of gold in nitro-mu-
riatic acid, a folution of muriate of tin recently pre¬
pared. The theory of this procefs is the following.
The gold in folution is in the ftate of yellow oxide.
It is deprived of part of its oxygen, and reduced to
the ftate of purple oxide by the tin. The purple
oxide is no longer foluble in the acid, and is there¬
fore precipitated. The fame effefl is produced when
a fait of tin is added, provided this fait be not fully
faturated with oxygen, for in that cafe no precipitate
is obtained. This is the reafon, as Pelletier has
ftiewn, that muriate of tin, after it has been for fome
time expofed to the air, loles the property of produ¬
cing the purple precipitate, becaufe it has abforbed
oxygen from the atmoiphere, and is not fufceptible of
combining with a greater quantity. For the fame
reafon no precipitate is obtained by the oxymuriate of
tin, or the fmoking liquor of Libavius, or the red ful-
phate of iron, becaufe both tbefe falts have their bafes
fully fatupated with oxygen. Other metallic folutions
have alio the property of decompofing and precipitat¬
ing the muriate of gold. The nitrate of filver pro¬
duces a reddifti precipitate, which is a mixture of white
muriate of filver and purple oxide of gold. The ni¬
trate of lead depofits a dark coloured fubftance, com-
pofed of muriate of lead and oxide of gold.
6. The metallic acids have no effedft whatever on
gold. Vauquelin found that chromic acid, mixed with
muriatic acid, gave it the property of diffolving gold.
This is owing to the chromic acid giving up part of
its oxygen, which appears to be the cafe, from its paf-
fing from its1 natural colour which is orange, to the
ftate of green oxide.
2105
Metallic
Ecids.
69 I
II. Adion of Alkalies, &c. upon Gold.
1. None of the alkalies have any aftion upon gold, .
or on its purple oxide, but the yellow oxide preci¬
pitated from its folution by means of the fixed al¬
kalies, and digefted for fome time with ammonia, is
readily converted into fulminating gold.
2. The earths have no adfion on gold in the metal-Earths,7
lie ftate 5 but in the ftate of purple or yellow oxide, it
combines with the earths which are vitrified by means
of the alkalies, and forms with them enamels, which
are of a violet or purple colour, or glafs of a golden-
yellow colour. It is on account of the latter property
that the yellow oxide is employed in the fabrication
of artificial topazes. It has been obferved that glafs
coloured by means of gold, and which contains a ccn-
fiderable proportion of oxide of lead or of manganefe,
has a remarkable property of changing to a permanent
purple or ruby-red colour, when it is flightly heated,
and long before fufion. This is fuppofed to be own¬
ing to fome change in the ftate of the oxidation of the
different metals.
3. The moft powerful falts, as the nitrates, the hy-Salts!°
peroxymuriates, have no aftion on pure gold. It has,
however, been obferved, that borax diminifties its co¬
lour, and that nitre which is employed in its purifica¬
tion, renders it more brilliant.
III. Alloys of Gold.
1. Gold is fufceptible of combination with moft me-Withane-
tallic fubftances, w'hich produce a very particular nic.
change on its properties. The alloy with arfenic is
brittle, hard, of a granulated texture, and of a very
pale colour. According to Mr Hatchett’s experi¬
ments, arfenic readily combines with gold raifed to a
common red heat, when the former is in the ftatc of
vapour, and particularly when the combination is made
in clofe veffels.
2. I he alloys of gold with tungften, molybdena, Tungiren,
chromium, titanium, and uranium, have not been ex- 6cc.
amined. ^
3. The combination of gold and cobalt is not pet-Cobalt,
ceptibly different from pure cobalt. This alloy re¬
duced to a fine powder, and heated in contadl with air,
gives, after its oxid .tion, and by ftrong heat, a deep
blue glafs. In Mr Hatchett’s experiments, one part of
cobalt and 14 of gold form a brittle alloy of a dull
yellow” colour. \Vith -glj- of cobalt the alloy wras brit¬
tle, but became dinftile with part.
4. Gold forms with nic kel a white and brittle alloy. Nickel.
In Mr Hatchett’s experiments °f nickel rendered
the alloy brittle. It was fcarcely, if at all, brittle with r
ZT Part, and with Tjfj of nickel it w’as completely
duflile. One part of nickel and 16 of gold give an
alloy of the colour of brafs.
5. Mr Hatchett formed an alloy of gold w ith man¬
ganefe. It was of a pale yellowifh-gray colour, had
fomething of the luftre of polifhed fteel, and fome
du&ility, although it wTas very hard. It contained *
about one-ninth of manganefe. Acids produced no ‘T'anf‘
effeft, nor w’as it altered by expofure to the air *. ^^ir-
6. Bifmuth fufed with gold, yields an alloy which Bifmuth,
is brittle in proportion to the quantity of bifmuth em¬
ployed. The fpecific gravity of this alloy is greater
4 S 2 than
692 C H E M
Gold, &c. than the mean. In Mr Hatchett’s experiments, this
v v —a]j0y was brittle, when the proportion of bifmuth
2114 amounted only to T9V0 Part>
Antimony. 7. Antimony combines with gold, and renders it
hard and brittle. Equal parts of thefe metals form an
alloy not much dift'erent in appearance from gold it-
felf. This compound was frequently employed by the
alchemifts in their refearches. Antimony was called
the royal bath. They pretended that the quantity of
gold was increafed when it was leparated from the
alloy, after having been fufed with this metal. But it
appears that this increafe of weight wras owing to
part of the antimony, which was not feparated from
the gold. The fulphuret of antimony was formerly
much employed for the purification of gold, to fepa-
rate by means of the fulphur, the metals which were
combined with it j and from this property of afting on
all the metals then known, excepting gold, the ful-
phuret of antimony was called by the alchemifts, the
2115 wolf °f the metals.
Mercury, 8. Gold unites very readily with mercury. If gold
be brought into contaft with this metal, it is inftantly
covered with it j and if gold leaf be triturated with
mercury, it totally difappears, and is diffolved in the
mercury j fo that even in the cold, mercury combines
with the whole quantity of gold with which it can be
alloyed. When the proportion of gold is increafed,
the amalgam becomes folid. When this operation is
performed in the large wTay, the combination is pro¬
moted by means of moderate heat. This amalgam is
ol a yellowiih white colour *, it is fufible at a moderate
heat, and cryftallizes in the form of quadrangular
prifms. It is decompofed by a ftrong heat, and the
mercury is diffipated. This amalgam is much employ-
21 iff cd in giving.
Zinc. 9* Gold combines with zinc by means of fufion.
This alloy is paler than gold, has little malleability,
and if the proportion of the zinc be confiderable, is
very brittle. An alloy confifting of equal parts of the
two metals, is of a greater fpecific gravity than the
mean, is very hard, fufceptible of a fine polilh, and is
not much altered by the air. It has been recommend¬
ed, on account of thefe properties, for the fabrication
2IIy of the mirrors of telefcopes.
’fin. 10. Gold combines eafily with tin by means of fu¬
fion. This alloy, it is faid, is the dread of the
workmen, becaufe it deprives gold of its du&ility.
They are even cautious in preferving gold from the
contact of the vapour of tin in fufion, which ren¬
ders the gold fo brittle, that it may be reduced to
powder in a mortar. It is extremely difficult to puri¬
fy gold after it has been alloyed with tin, for it does
not pafs into the cupel with lead or with bifmuth.
Nitre, borax, and even the hyperoxymuriate of mer¬
cury, which are often employed with this view, do
not always fucceed. The moft fuccefsful method is
by treating the alloy with fulphuret of antimony, or
with muriatic acid, which diffolyes the tin when it is
in confiderable proportion. But in the experiments of
Mr Hatchett and Mr Bingley, it appears that the uni-
verfal opinion which has hitherto prevailed, of tin be¬
ing fo injurious to the duaility of gold, is to a certain
extent, erroneous ; and it appears probable, that the
duaility of gold being deftroyed, as was fuppofed,
even by the fumes of tin,, ought to have been afcribed
2
I S T R y.
to other metals, as bifmuth, lead, antimony, or zinc, Gold, &c.
wdth which the tin was contaminated. i——y—-j
11. Lead very readily combines with gold by fu-
fion ; this alloy deprives the gold of its duaility, and
diminifhes the colour. So fmall a proportion as -rgW
part of lead deftroys the duaility of gold. This al¬
loy, it has been already ftated, is made for the purpofe
of purifying gold from other metals, in confequence of
the eafy oxidation and vitrification of the lead. anp
12 Gold is eafily alloyed with iron, and forms withlr0n'
it a hard brittle mafs. Some of thel'e alloys are fb
hard, that Dr Lewis found them fit for cutting inftru-
ments. Equal parts of iron and gold form an alloy of
a gray colour. Four parts of iron and one of gold af¬
ford an alloy nearly of the colour of filver, and the fpe¬
cific gravity of this alloy has been afcertained to be lei’s
than the mean. One part of iron alloyed with 12 of
gold, according to Mr Flatchett, w7as of a pale-yellow-
ilh gray colour, and was fo du£lile that it might be
rolled and cut. When gold is fufed, it adheres readily
to iron ; and hence it has been propofed to folder fmall
pieces of fteel with gold, which feems to be preferable
to copper. _ 2I20
13. Gold readily combines with copper by fufion. Copper.
This is one of the moft important alloys, on account of
the hardnefs which copper communicates to gold, with¬
out diminiftring its colour. This alloy, according to
Mufchenbroeck, pofleffes the greateft hardnefs, with¬
out fenfibly diminifhing its duftility, when the propor¬
tions are one part of copper and feven of gold. This
alloy is more fufible than gold, and on that account
it is employed as a folder for that metal. The gold
coin of moft countries confifts of this alloy. The pro¬
portions in the gold coin of Britain and France are 11
parts of gold to one of copper. According to Brifi'on,
the fpecific gravity of this alloy is greater than the
mean. It is 17.486, but it ought to be 17.153. But,
according to Mr Hatchett’s experiments, there is no
mutual penetration in the alloy of thefe metals, and
therefore no increafe of denfity. On the contrary,
fome degree of expanfion was obferved. Four hun¬
dred and forty-two grains of gold of fpecific gravity
19.172, were alloyed with 38 grains of copper of fpe-
’ cific gravity 8.875. ^ fpec>hc gravity of the alloy
was found to be 17.157. The bulk of the alloyed
mafs amounted to 27.98, while the natural bulk of the
two metals before combination was 27.32, which ftrews
an increafe of expanfion of the alloyed mafs equal to
T<k<L. Mr Hatchett obferves that Briffon’s experiment
was probably made on part of a large bar or ingot, in
which it generally happens, that the two metals are
very unequally diffufed, and this inequality, which is
greater according to the quantity of the metal, is * Phil.
found to vary with the form, nature, and pofition of ^ranf.
the mould, and therefore to produce variations in the180-’
fpecific gravity *.
14. Silver forms an alloy with gold. Homberg silven
found, that equal parts of thefe metals fufed together
in a crucible, formed an alloy v\hich contained of its
weight of filver. One part of filver and two of gold,
according to Mufchenbroeck, give to the alloy the
greateft degree of hardnefs. One-twentieth part of
filver changes the colour of gold very fenfibly. This
alloy is employed for foldering gold, being more fufi*
ble than this metal.
15. Mr
CHEMISTRY.
&c. 15. Mr Hatchett obferves, that the obvious inference Cobalt,
to be deduced from his experiments is, that only two Manganefe,
metals are proper for the alloy of gold coin. Thefe Nickel,
are, filver and copper. All other metals either confi- Tin,
derably alter the colour, or diminilh the duftility of Iron,
gold. According to the fame philofopher, the dudti- Platina(E),
lity of gold is diminiflied by different metallic fub- Copper,
fiances, nearly in the following decreafing order : Silver *.
693=
Gold, &c.
* Phil,
Tratif,
1803, p5.
Bifmuth, T
Lead, > Thefe are nearly equal in effe£l.
Antimony, J
Arfenic,
Zinc,
The ufes of gold, many of which have been al-Ufes.
ready detailed, in defcribing its properties and combi¬
nations, are too familiar to require particular enume¬
ration (f).
Sect.
(e) Mr Hatchett fuppofes that the platina not being quite pure, the place he has affigned to it is perhaps
not precifely that which it ought to occupy.
(f) The metals which were earlieft known, were long diftinguifhed by particular names and charadlers, of
which the following account is taken from the elaborate refearches of Profeffor Beckmann. The following ta¬
ble exhibits their names and characters.
Metals.
Gold,
Silver,
Mercury,
Copper,
Iron,
Tin,
Lead,
Names.
Sun,
Moon,
Mercury,
Venus,
Mars,
Jupiter,
Saturn,
Characters.
0
5
?
$
n
k
It cannot be doubted, Profeffor Beckmann obferves, that thefe names were firft given to the heavenly bodies y
and the metals which were then known, amounting to the fame number, were fuppofed to have fome affinity
or relationiliip to the planets, and with them to the gods, and were accordingly named after them. “ To
each god was affigned a metal, the origin and ule of which was under his particular providence and govern¬
ment •, and to each metal were afcribed the powers and properties of the planet and divinity of the like name j
from wffiich arofe, in the courfe of time, many of the ridiculous conceits of the alchemifts.
“ The oldeft trace of the divifion of the metals among the gods is to be found, as far as I know, in the reli¬
gious rvorffiip of the Perfians. Origen, in his refutation of Celfus, who aflerted that the feven heavens of the
Chriflians, as well as the ladder which Jacob faw in his dream, had been borrowed from the myfteries of Mi¬
thras, fays, ‘ Among the Perfians the revolutions of the heavenly bodies were reprelented by feven flairs,
which conduCled to the fame number of gates. Thfe firft gate was of lead 5 the fecond of tin ; the third of
copper 5 the fourth of iron ; the fifth of a mixed metal ; the fixth of filver, and the feventh of gold. The
leaden gate had the flow7 tedious motion of Saturn j the tin gate the luftre and gentlenefs of Venus ; the third
was dedicated to Jupiter •, the fourth to Mercury, on account of his ftrength and fitnefs for trade ; the fifth to
Mars j the fixth to the Moon, and the laft to the Sun.’ ‘ Celfus de quibufdam Perfarum myfteriis fermonenv
facit. Harum rerum, inquit, aliquod reperitur in Perfarum doCtrina Mithracifque eorum myfteriis vertigium.
In illis enim dute caeleftes converfiones, alia ftellarum fixarum, errantium alia, et anirme per eas tranfitus quo-
dam fymbolo repraffentantur, quod hujufmodi eft. Scala altas portas habens, in fumma autem oCtava porta.
Prima portarum plumbea, altera ftannea, tertia ex asre, quarta ferrea, quinta ex sere mixto, fexta argentea,
feptima ex auro. Ir^iTrvXog, 1x1 S’asvrn stvAjj 'H tmv TrvXav /uoXi^ov, » xaisvmgov, sf
ytoiXx.ov, « cr;Sii£ov, \ Tri/XTrry) xxgxrov vofAia-luxroi, « ixTii •fcQvtrov h) Primum affignant
Saturno tarditatem illius fideris plumbo indicantes : alteram Veneri, quam referunt, ut ipfi quidem putant,
ftanni fplendor et mollities; tertiam Jovi, aheneam illam quidem et folidam : quartam Mercurio, quia Mercu-
rius et ferrum, uterque operum omnium tolerantes, ad mercaturam utiles, laborum patientiffimi. Marti quin-
tam, insequalem illam et variam propter mixturam. Sextam, quae argentea eft, lume j feptimam auream foli
tribuunt, quia folis et lunse colores haec duo metalla referunt.’ Contra Ceifum, lib. vi. 22. p. 161. Here
then is an evident trace of metallurgic aftronorny, as Borrichius calls it, or of the aftronomical or mythological
nomination of metals, though it differs from that ufed at prefent. According to this arrangement, tin belong¬
ed to Jupiter, copper to Venus, iron to Mars, and the mixed metal to Mercury, The conjeCture of Borrichius,
that the tranfcribers of Origen have, either through ignorance or defign, tranfpofed the names of the gods, is*
highly probable : for if we refleCt that in this nomination men, at firft, differed as much as in the nomination
of the planets, and that the names given them were only confirmed in the courfe of time, of which I ffiall foo:v
produce proofs, it muft be allowed that the caufes affigned by Origen for his nomination do not wrell agree
with.
694
Platina,
&c.
C H E M
Sect. XXII. Of Platina and its Combinations.
Hiftory. Platina in moft of its properties is equal to gold,
but in others, it is luperior. It was firft clearly afeer-
tained to be a diftinft metal, by Scheffer, a Swedifli
chemift, in the year 1752. It had been indeed taken
notice of at an earlier period. A quantity of it was
I S T Pv Y.
brought from Jamaica in 1741, by Mr Wood. It is Plating,
particularly mentioned by Antonio de Ulloa, a Spa- &c*
nilh mathematician, in the account of his voyage to "v—
Peru with the French academicians, to meafure a de¬
gree of the meridian, which was publiihed in 1748.
After this period numerous experiments were made
upon this new fubftance, all of which tended to prove
that it is a different metal from any formerly known.
Scheffer
with the prefent reading, and that they appear much jufter when the names are difpofed in the fame manner as
that in which we now ufe them. Borrichius arranges the words in the following manner ; Secundam portam
mciunt Jovis, comparantes ei ftanni fplendorem et mollitiem ; tertiam Veneris aeratam et folidam; quartam
Martis, eft enim laborum patiens, seque ac ferrum, celebratus hominibus; quintam Mercurii propter mifturam
inaequalem ac vanam, et quia negotiator eft ; fextam Lunas argenteam ; feptimam Solis aureann 01. Borrichius
de ortu etpro^refju chemhe. Hafnise 1668, 4to. p. 29.
“ Phis aftrological nomination of metals appears to have been conveyed to the Brachmans in India ; for we
are informed that a Brachman fent to Apollonius feven rings, diftinguiftied by the names of the feven ftars or pla¬
nets, one ov which he was to wear daily on his finger, according to the day of the week. This can be no other-
wile explained thah by fuppofing that he was to wear the gold ring on Sunday ; the filver one on Monday : the
non one on Fuefday, and fo of the reft. Allufion to this nomination of the metals after the gods occurs here
and there in the ancients. Dydimus, in his Explanation of the Iliad, calls the planet Mars the iron ftar. Thofe
who dream of having had any thing to do with Mars are by Artemidorus threatened with a chirurgical operation,
for this reafon he adds, becaufe Mars figmfies iron. Heraclides fays alfo in his allegories, that Mars was very
proper y confidered as iron ; and we are told by Pindar that gold is dedicated to the fun.
ato likewife, who ftudied in Egypt, feems to have admitted this nomination and meaning of the metals,
f C ZTfl J1 AUr,ed ^ bJ MarfiIlus Flcinus 5 but I have been able to find no proof of it, except where he
win enf th3 a."d •A:tl antis’ exterior walls were covered with copper and the interior with tin, and that the
J de, '7ere .of Sold* 11 ,s not improbable that Plato adopted this Perfian or Egyptian repreferta-
difcinles 16 thC ,planetS t0 tl?e j but perhaps it was firft introduced into hi* fyftem only by his
d iciples. They feem however, to have varied from the nomination ufed at prefent ^ as they dedicated to Ve-
elearumer,Theb]aq ^ .pnn^pa1 ^mponent part of which is indeed copper j to Mercury tin, and to Jupiter
fideredTo be Th ft' u -VaS1 " miXtUre °f ^°ld and fllver ’ and on this account Was probably con¬
ing thefe noble met fis ’ beCaufe m the earl-y Periods mankind were unacquainted with the art of feparat-
their^ames^ffoTd the Planfts and ^tals are generally expreffed when one does not choofe to write
tween things which in redi/Hf exjmp ^ °w rt'adily the mind may be induced to fuppofe a connexion be-
rwhofe onin?n rh 1 Y ^ 0r rehUOn t0 each °ther* Antiquaries and aftrologers, according
deitie^^f the1 fam^nam3"6^'?ere‘ dldl^§uidle;d by thefe charafters, confider them as the atfrib^tes of the
and perfeaion anSTems J* b th.e ^ Per5ods arao^ the Egyptians was the fymbol of divinity
dafty as when Yu-round d l'’ f girient proPnety t?.hav^ been cbolen by them as the charader of the fun, elpe-
the Liffion of rays The/ ™ Pr.°Jeain^ from its circumference, it may form feme reprefentationof
bodierZ apnearsYnde rh /fC,r : "n'" the image of the moon, the only one of the heavenly
Saturn j -4 the thunderbolts Yf T*™'*-0 1 e n,1bed eye> The charader b is fuppofed to reprefent the feythe of
toge,h£r hisfl'ie,di ? thc,ooki"s^
the charaaer affigne/to rollf aW?"H t,le with this mythological fignification only in
others feemed to be inferior inTiff/r Y d S ^ cben,ltts’ waS the moft pcrfea of metals, to which all
by a femicircle, which for the more nY r blU'er aPProached neareft to it ; but was diftinguiftied only
moft remarkable appeaYance of rh ei ‘ 1Cl!Ity’ was d^au'n double, and thence had a greater refemblance to the
metals, as thev feemed to have T ’ fr "T* °f which tbis .^etal had already obtained. All the other
pofed of the charaders affiened to^rh '/1^ °r ' * ' t0 g°^d °r Pdver’ were diftinguifhed by charaders com-
filver colour. The crofs placed at/h F>?°US T-t' ln the char5a-the adepts difeover gold with a
fignificaticn, expreffes in their onini C r ° ^ amor,g tbe Egyptian hieroglyphics had a myfterious
or gold. This fomethin? is 1 knovv,not without which quickfilver would be filver
the charader 9. The charader i°.Ulti c°Ppe^’ the poflible change of which into gold is exprefied by
in a more concealed manner • for ir LC,.attS X Y lke honourable affinity alfo ; though the femicircle is applied
the upright line ouglu or^yVo tmiclltEe^lirf'10 ProPereiI mode of writing, the point is wanting a, top, or
lleel ; and on this account i, produces iLh l-T f, ’ “'“lPhilofophical gold is concealed in
of the fomething unknown : for this realm th ^ 7 Of tm one half is diver, and the other confiils
is predominant, and a fimilitude is obferved b e Cro iY11’ 1 Vr half .mo.on appears in 4. In lead this fomething
and the filver charader is only fufpended rV ^ f Hencc ln lts charader b the crofs ftands at the top,
“ The mvtholncrircl c ‘2 7 Y'P^fd T" the nsht hand behind it.
7 ^ g fignification of thefe charaders cannot be older than the Grecian mythology j but the che¬
mical
Katina,
See.
2124
Where
found.
C H E M
Scliefrer gave it the name of white gold, becaufe it re-
| fembled this metal in many of its properties. In the
year 1754, Dr Lewis publifhed an account of a very
full and elaborate fet of experiments on platina, in the
Philofophical Tranfaftions. The properties of this
new metal were ftill farther inveftigated by Margraaf
in 1757 and by Macquer and Beaume in 1758^ It
became afterwards the fubje<ft of refearch with many
other philofophical chemifts. Among thefe may be
mentioned Buffon, Bergman, Sickingen, and more
lately Guyton, Lavoifier, and Pelletier. It was at
laft denominated platina, fignifying littlefilver, from
the Spanifh word plain, filver,
2. Platina has only been found among the gold
ores of South America, and efpecially in the mine of
Santa Fe near Carthagena, and in the diftridl of Choco
in Peru. It is found in the form of fmall giains or
feales, of a white or grayifn colour, intermediate be-
twreen that of filver and iron. Thefe grams are mix¬
ed with feveral other fubftanoes, as particles of gold,
a black ferruginous fand, and fome particles of mer¬
cury. Some of thefe grains extend under the hammer,
others which feem to be hollow, containing particles
of iron and a whitifh pow'der, break to pieces. To
I
,Sr T R Y- . 695
thefe grains of iron is aferibed the magnetic property Platina,
which platina feems to poflefs (g). Sec.
3. To obtain platina in a date of purity, it is firft
feparated from the fubftances with which it is conta- Punfica.
minated. Mercury is driven off by expofing it to a tion.
red heat, and the particles of iron are * feparilted by
the magnet.. The grains of platina are then heated
with muriatic acid, wmich diiTolves the remaining part
of the iron. By this procefs, Bergman has obferved,
that the platina diminifhes m weight about o.oy.
1 he platina is now only alloyed with gold, which is
to. be ieparated by diffolving both in nitro-muriatic
acid, and by precipitating the gold by means of the
gteen fulphate of iron. But even aftet thefe procef-
fes, the platina is not in a flate of abfolute purity, as
will appear afterwards (h). ^ 2I2g
4. I his metal is of a white colour, but lefs bright Properties,
than filver, and it poffelles nothing of the brilliancy
of either filver or gold. Platina is the denfeft body,
and therefore the heavieft yet known. Its fpecific
gravity, when it is hammered, is 23 5 or, according
to Chabaneau, 24* According to Guyton, it comes
next to iron and manganefe in hardnefs. It poffeffes
very confiderable malleability, for it may be ham¬
mered
mical may be traced to a much earlier period. Some, who confider them as remains of the Eayptian hierogly¬
phics, pretend that they may be difeovered on the table of Ifis, and employ them as a proof of the high anti-
qm y, if not or the art of making gold, at leaft of chemiftry. We are told alfo that they correfpond with
many other charaaers which, the adepts have left us as emblems of their wifdom.
“ If we are defirous of deciding without prejudice refpeaing both thefe explanations, it will be found neceffary
to make ourfelves acquainted with the oldeft form of the ebaraaers, which, in all probability, like thofe ufed
in writing, were fubjeefted to many changes before they acquired that form which they have at prefent. I can,
however, mention only three learned men, Saumaife, Du Cange, and Huet, who took the trouble to colka
ne e charaaers. As I am a.raid that my readers might be difgufted were I here to infert them, I fliall give a
Ihort abftraa of the conclufior. which they form from them ; but I mult firft obferve that the oldeft manuferipts
cirxer very much in their reprefentation of thefe charaaers, either becaufe they were not fully eftabliftied at the
periods when they were written or becaufe many fuppofed adepts endeavoured to render their information more
enigmatical by wilfully confounding the charaaers; and it is probable alfo that many miftakes may have been
committed by tranfenbers. J
1 he char.-ia.er or Mars, according to the oldeft mode of reprefenting it, is evidently an abbreviation of the
word under which the Greek mathematicians underftood that deity ; or, in other words, the firft let-
er 0, with the laft letter 5 placed above it. The charaaer of Jupiter was originally the initial letter of ZsvS ;
and m the oldeft manufcupts of the mathematical and aftrological works of Julius Firmicus the capital Z only
is ufed, to which the laft letter 5 was afterwards added at the bottom, to render the abbreviation more diftina.
1 hefuppofed lookmg-glafs of Venus is nothing elfe than the initial letter, diftorted a little, of the word
which was the name of that goddefs. The imaginary feythe of Saturn has been gradually formed from
trie two firft letters of his name which tranfenbers, for the fake of difpatch, made always more convenient
for ufe, but at the fame time lels perceptible. To difeover in the pretended caduceus of Mercury the initial
letter of his Greek name S-nA&wy, one needs only look at the abbreviations in the oldeft manuferipts, where
they will find that S was once written as C ; they will remark alfo that tranferibers, to diftinguifh .this abbre-
T Tl'T the rCl 1plaCed the C thuS U ’ and added undtr k the next letter r. If thofe to whom
tn.s de?Ua’°" appe^ ™Pr^able will only take the trouble to look at other Greek abbreviations, they will find
many that differ ftid farther from the original letters they exprefs than the prefent character $ from the C and r
united. It is poftible alfo.that later tranferibers, to whom the origin of this abbreviation was not known, may
have endeavoured to give it a greater refemblance to the caduceus of Mercury. In ftiort, it cannot be denied
hat many other aftronomical charaaers arc real fymbols, or a kind of proper hieroglyphyics, that reprefent cer-
Invent Yr^ °r °irCUrnftanCeS» 1,ke the charaaers of Aries, Leo, and others quoted by Saumaife. Ni/l. of
Pliina CtW metallic fubftances which are ufually found accompanying
Th cintak! klniS,Qf fe/rUgu,n°US ’ °f WhlCh 006 is attraaed ^ the maSnet’ and rol^le in acids,
rnni f o rl l?’ T 16 .other,has no magnetic property, and is only partially foluble in acids. This laft
contains a confiderable proportion of chromic acid. slnn. de Chim. xlviii. 154
mil be mentioned'in^'foturc^^Uon. haVe difC°Vered Plati"a’ ^ 'ate Thefe
r
2127
Fufing
point un¬
known.
2128
Oxidation.
2x29
Yellow ox¬
ide.
C H E M
mered out, although with difficulty, into very thin
plates; and it is fo duftile, that it may be drawn out
into wire ttto an diameter. The tenacity
of platina is very confiderable. A wire of .078 of an
inch in diameter will fupport a weight without break¬
ing, equal to more than 274 lbs. avoirdupois.
5. Platina is the molt infulible of all the metals.
The temperature at which it enters into Fufion is un¬
known. But fmall particles of platina have been
fufed by means of the blow-pine, or by direfling a
ftream of oxygen gas on red-hot charcoal. Guyton
alfo fucceeded in fufing it by means of a flux, compo-
fed of eight parts of pounded glafs, one of calcined
borax, and one-half part of charcoal in powder.
When platina has been expofed to a white heat, it may
be welded by hammering, like iron.
6. As platina is infufible in the ftrongeft furnace
heat, fo it remains otherwife unchanged (1). It does
not appear to undergo, like moft other metals, any
degree of oxidation ; but if platina be dilfolved in 16
times its weight of nitro-muriatic acid, by boiling
the folution becomes at firfl of a yellow, and then
changes to a brown colour. This folution is precipi¬
tated by means of lime, and the precipitate is in the
form of a yellowdffi powder, which is the oxide of pla¬
tina. The proportion of oxygen in this oxide is fup-
pofed not to exceed .07. But according to the ex¬
periments of Mr Chenevix, it is compofed of
Platina, 87
Oxygen, 13
I S T R Y.
phofphuret to a ftrong heat, the phofphorus is feparat- Platln*,
ed, and burns on the furface, and the metal remains, &:r‘
behind very pure and malleable. Pelletier has propof-
ed this procefs for the purification of platina from other
metals. # ... 2132
9. Sulphur has been found in combination with na-Sulphutet
tive platina. When native platina is expofed to the
aflion of the blow7-pipe on charcoal, it exhales the pe¬
netrating odour of fulphur, accompanied with a vapour
which does not render gold white, and which re¬
quires a higher temperature to fublime it than mer¬
cury *. * Ann. dt
Chitn.
I. Salts of Platina. xxxvtii.
Sulphate of Platina.
149.
By adding fulphuric acid to a folution of platina in
muriatic acid, Mr Chenevix obtained an infoluble fait,
which he found to be compofed of
Oxide of platina, 54.5
Acid and water, 45-J
100.0
2. Sulphate of Platina and Potaffi.
This triple fait is formed by adding a folution of •
potalh to fulphate of platina. The component parts of
this fait are, fulphuric acid, oxide of platina, and pot¬
affi ; but the proportions have not been afcertained by
Bergman, who examined it.
100
The fame chemift alfo found, that in the reduflion of
this oxide of platina, it became of a green colour, and
remained for fome time in that Hate. Ammonia af-
fumes a green colour when it holds oxide of platina in
folution. This Mr Chenevix confiders as a fecond
oxide of platina, and it contains
Platina, 93
Oxygen, 7
* Phil. ' IOO
7ranf.
1S03. 314. Platina has alfo been oxidated by means of eleftricity.
In Van Marum’s experiments, a wire of this metal
through which eleftric fparks were fent, burnt with a
white flame, and was diffipated in the form of fine
powder or duft.
7- Azote, hydrogen, and carbone, have no aflion
21,I whatever on platina.
Phofphu- 8- Phofphuret of platina was formed by Pelletier by
ret. mixing together equal parts of platina and phofphoric
glafs, with one-eighth of charcoal. This mixture being
expofed to the temperature of 3 20 of Wedgwood for an
hour, yielded a fmall button of phofphuret of platina,of a
filvery white colour, part of which had aflumed the
form of cubic cryftals. It was fo hard as to ftrike fire
with fteel, and was not attrafled by the magnet. It was
covered with a dark coloured glafs, which afterwards
became green, bluifli, and white. By expofing this
2130
Green ox¬
ide.
3. Sulphate of Platina and Ammonia.
This triple fait is formed in the fame way as the
former, by adding ammonia to the fulphate of platina.
4. Nitrate of Platina.
Nitric acid has no aflion on platina, but it diflblves
the yellow oxide. Mr Chenevix precipitated the ox¬
ide of platina from its folution in nitro-muriatic acid
by means of lime, and although it was added in ex-
cefs, a great portion of platina remained in the liquor.
The precipitate was rediflblved in nitric acid, and eva¬
porated to drynefs. The refult was, a fubnitrate of
platina, which confifted of
Yellow oxide 89
Nitric acid and water 11
100
5. Nitrate of Platina and Potafh.
When potafh is added to a folution of nitrate of
platina, cryftals are depofited forming a triple fait,
and compofed of nitric acid, oxide of platina and pot¬
affi.
6. Nitrate of Platina and Ammonia.
This triple fait is formed by adding ammonia to a
folution of nitrate of platina.
^ 1) Guyton piopofes to conftrufl: a pyrometer of platina. See Ann. de Chim. xlvi. 276.
7. Muriate
C H E M
Platina,
&.c. 7. Muriate of Platina.
Muriatic acid has no a&ion on platina, but the mu-
Prepara- fiate °f platina may be obtained by diffolving the metal
tion. in nitro-muriatic acid. Boiled in 16 parts of a mixture
confiding of one part of nitric acid and three parts of
muriatic acid, it is gradually diflolved with effervef-
cence. It may be alio diflblved in oxymuriatic acid.
The folution of platina in muriatic acid is of a reddifh
or deep brown colour. It is extremely acrid and
caultic, corrodes and burns animal matters, and
leaves a dark brown fpot on the fkin. When the fo¬
lution is concentrated, it depofits on cooling, fmall ir¬
regular cryftals, nearly in the date of powder, and of
Properties. a brownidi-yellow colour. When thefe crydals are
wadied and dried, they are found to be lefs foluble by
boiling in water, than even the fulphate of lime. The
folution is of a yellow colour. The muriate of platina
has a hardi, adringent tade j it is decompofed by
heat j the acid is driven off, and the oxide remains.
It is alfo decompofed by concentrated fulphuric acid.
Potadi produces in this folution, fmall reddidi crydals,
frequently in the form of o&ahedrons, condituting the
triple fait already defcribed. The fame triple fait is
formed by the fulphate of potadi. Ammonia, or the
muriate of ammonia, alfo forms a triple fait, by being
added to the folution of muriate of platina. Soda in
fufficient quantity occafions a precipitate of the yellow
oxide of platina, and a triple fait alfo is formed. Mr
Chenevix found that the infoluble muriate of platina is
compofed of
213s
Cempoii-
tioa.
Oxide of platina 70
Acid and water 30
100
8. Muriate of Platina and Soda.
Till the experiments of Collet-Defcodils, little was
known of this triple fait. It may be obtained by add¬
ing to a folution of platina a fait with bafe of foda.
By concentration and cooling it crydallizes in the
form of long prifms, and fometimes in that of triangular
tables, of a yellow or red colour. It is very foluble
in water, and alfo in alcohol. It is decompofed by
muriate of ammonia, and by a folution of foda; but
an excefs of this fait re-diflblves the precipitate. It
may be reduced by the a&ion of the blowpipe on char¬
coal. This cryftallized triple fait, if it has no excefs
of acid, changes from a red colour to a green by ex-
pofure to the air. If in this date it be diffolved in
water, and oxymuriate of lime be added to it, a deep
blue precipitate is formed, which being walked and
colle&ed, is foluble in muriatic acid, and communi¬
cates to it a beautiful blue colour. The addition of
alcohol deprives the folution of its colour, but the oxy-
de muriate of lime reftores it *.
Chim. xlviii. . _ .
p. 165. 9* Muriate of Platina and Potalh.
This fait is formed by adding potalh to a folution of
muriate of platina. Small cryftals of a red colour in
the form of o&ahedrons, are precipitated, which are a
triple fait confifting of muriatic acid, oxide of platina
and potalh.
Vol. V. Part II.
I S T R Y.
10. Muriate of Platina and Ammonia.
1. A limilar triple fait is formed by adding ammo¬
nia to the folution of muriate of platina. The triple
fait is precipitated in the form of cryftalline grains, of
a reddilh-yellow colour, which are foluble in water.
By evaporating the folution of thefe triple falts to dry-
nefs, and by expofing it to a ftrong heat, the platina
is reduced. This fad! with regard to the fufibility of
platina by means of potafli or ammonia, was obferved
by Bergman, and it is by this procefs that platina is
purified and wrought.
2. When this fait is precipitated by means of potalh,
a fulminating platina is obtained. This, according to
Fourcroy and Vauquelin by whom it w’as prepared, is
a compound of oxide of platina and ammonia. When
it is expofed to hidden heat, it decrepitates and is
agitated with a rapid motion, but when the heat is gra¬
dually applied, it detonates violently *. * * .
J * Anna!, de.
xi. Oxalate of Platina. Cbim. xlix.
p. 179.
Oxalic acid combines with the oxide of platina, and
affords by evaporation cryftals which are of a yellow
colour.
12. Benzoate of Platina.
Benzoic acid, according to Trommfdoif, diffolves a
fmall quantity of the oxide of platina. When this
folution is evaporated, it cryftallizes. This fait under¬
goes no change by expofure to the air, and is not very
foluble in water. The acid is driven off by heat, and
the oxide of platina remains behind.
II. Alloys.
1. Platina combines with many of the metals, and
forms with them alloys, lome of which are of conlider-
able importance in the working of this metal.
Platina forms an alloy with arfenic, which is brittle Combmes
and very fulible. It is in this ftate of alloy that pla- with arfe.
tina is fufceptible of being formed into different uten-nic*
fiB and inftruments for which it is peculiarly fitted.
It is firft fufed with this metal, and then caft into*
moulds, at firft in the form of fquare plates. It is then
expofed to a red-heat, and hammered into bars. By
the heating and hammering, the arfenic is driven off
and the ^ metal is purified and becomes infufible, but
retains its du&ility, fo that it maybe wrought*like
iron. °
2. The alloys of tungften, molybdena, chromium,
columbium, titanium, uranium, and manganefe, are
unknown ; nor have the alloys of cobalt and nickel
with this metal been examined.
j. —“ wuu oiunurn oy means ot Biimuth.
fufion. This alloy is fufible and hard in proportion
to the quantity of bifmuth. It is altered bv expofure
to the air ; it becomes yellow, purple, and black.
forms Tverv brMi'7 l,C°mb W!,i' ^
xorms a very buttle alloy. The antimony may be fe-
parated by means of heat, but not completely. Some
part remains, which ditninilhes the weight and dudti-
lity of the platina.
5; It has been found extremely difficult to combine
platina and mercury.. Guyton had obferved that the Mercury>
adhelive force of platina and mercury is greater than
4 ^ that
<598
CHEMISTRY.
Platina,
&c.
9140
Zinc.
2141
Tin.
2142
Lead.
2143
Iron.
2I44
Copper.
. 2145
Silver.
2146
Gold.
that of metals which do not combine with it, and
that it is not inferior even to thofe which readily
form alloys; from which he conjefhired that the alloy
of platina and mercury might be effe&ed by the fol¬
lowing procefs. He placed a very thin plate of pure
platina at the bottom of a matrafs containing a quan¬
tity of mercury. The matrafs was put upon a fand
bath, and heat applied, till the mercury boiled and the
matrafs became red-hot. 'When the platina was taken
out, it W'as found to have acquired additional weight,
and to have become very brittle. But this combina¬
tion is different from the other combinations of mercury
with the metals, for the platina did not lofe its folid
form. Mr Chenevix, inthecourfe of experiments and re-
fearches refpe&ing a fuppofed new’ metal called palladi¬
um, fucceeded in forming an amalgam with platina
and mercury. He heated purified platina in the form
of fine powder, with ten times its weight of mercury,
and rubbed them together for a long time. The refult
was an amalgam of platina, which being expofed to a
violent heat, loft all the mercury it contained, and the
original weight of the platina remained.
6. Platina readily combines with zinc, and forms
with it a fufible alloy, of a bluifh colour, brittle, and
hard. By heating, the zinc is fublimed, and burns on
the furface.
7. Platina alloys readily with tin. This alloy is
one of the moft fufible. It is hard and brittle,
when the twro metals are in equal proportions ; but
tin in the proportion of 12 parts to one of platina,
affords a very du&ile alloy, which becomes yellow
by expofure to the air. From this it appears that pla¬
tina diminifhes the duflility of tin.
8. Platina readily combines with lead, by means of
fufion. An alloy of equal parts of thefe metals is of
a purplifh colour, granulated in its frafture, brittle,
and eafily altered by expofure to the air. The cupel-
lation of platina by means of lead has been an object
of confiderable importance with chemifts, in the
view of being able to purify it in the fame w>ay as
gold and filver ; but on account of the infufibility and
refradlory nature of platina, the attempts that have been
made have rarely fucceeded.
9- Dr Lewis failed in his attempt to combine pla¬
tina wdth iron, but he obtained an alloy by fufing to¬
gether platina and caft iron. This alloy urns ex¬
tremely hard, and poffeffed fome degree of dudftility.
Platina, as it is found native, is frequently alloyed with
iron.
1 o. Platina combines with copper by means of fufion,
and gives it hardnefs. When the proportion of cop¬
per is three or four times greater than that of platina,
the alloy is du&ile, fufceptible of a fine polilh, and is
not altered by expofure to the air. This alloy has been
employed in the fabrication of mirrors for telefcopes.
11. Platina readily combines with filver by fufion,
although a very ftrong heat is required. The platina
greatly mcreafes the hardnefs of filver, but diminilhes
its whitenefs. When this alloy is ke^t in fufion for
lome time, the two metals are feparated. Durina-
this fufion, Dr Lewis obferved the filver forced to^
wards the fides of the crucible with a kind of explo-
fion. r
metals. Platina diminilhes the colour of gold, unlefs Palladium,
it be in very fmall quantity. When the proportion of ^cc-
platina is above the colour of the gold begins to 1 v f
be altered. There is no perceptible change in the
fpecific gravity or the ductility of gold from this alloy.
Platina, on account of its peculiar properties, its in¬
fufibility, denfity, and indeftrudlibility, could it be ob¬
tained in fufficient quantity, and at a moderate price,
W’ould undoubtedly prove one of the moft ufeful, and
moft important of the metals yet known. The import¬
ance and utility of platina, on account of its fcarcity,
have been hitherto limited to chemical purpofes j and
for different chemical inftruments and utenfils, it has
been found peculiarly appropriate, as there are few che¬
mical agents whofe effefts it cannot refift. There is
indeed little doubt but it might be employed with equal
advantage in the conftru£fion of inftruments and uten¬
fils, in various arts and manufadlures.
Sect. XXIII. Of Palladium^ a fuppofed new Metal,
and of Iridium and Osmium, two new Metals obtain¬
ed from crude Platina.
2147
12. Gold combines readily with platina, but it re¬
quires a very powerful heat for the fufion of thefe two
I. In the month of April 1803, the difeovery of a Palladium
new metal, to which the name of Palladium was given, announced,
was announced in London. It was faid to pof-
fefs the following properties : “ 1. It diffolves in pure
nitric acid, and makes a dark-red folution. 2. Green
fulphate of iron throws it down in the ftate of a regulus
from the folution. 3. If yuu evaporate the folution,
you get a red calx, which diffolves in muriatic or other
acids. 4. It is throwm down by quickfilver, and by all 2 g
the metals, but gold, platina, and filver. 5. Its fpeci-Properties,
fic gravity, by hammering, is only 11.3 ; but by flat¬
ting as much as 11.8. 6. In a common fire the face
of it tarnilhes a little, and turns blue j but becomes
bright again, like other noble metals, on being ftronger
heated. 7. The greateft heat of a blackfmith’s fire
would hardly melt it. 8. But if you touch it, while hot,
wdth a fmall bit of fulphur, it runs as eafily as zinc.”
Nothing was faid of the hiftory of the difeovery j but
from the unufual manner in which it was announced, Mr
Chenevix, conceiving it to be an impofition, procured Mr Chene.
a fpecimen, which being fubje&ed to various tefts, he v.ix’s iufpi-
found could not be referred to any of the known metals. c'ons .atK*
He afterwards purchafed the whole quantity which ments.'
was offered to fale. The fubftance had been wrought
by art, had been rolled out in flatting mills, and was
offered for fale in thin laminae. The largeft, about
three inches in length, and half an inch in breadth,
weighing about 25 grains, were fold at a guinea. When
this fubftance was polifhed, it could fcarcely be dif-
tinguifhed from platina. It was flexible, but not very
elaftic. The fpecific gravity of fome pieces was 10.972,
while others w7ere only 11.482.
The effe&s of galvanic eleflricity upon palladium
were the fame as upon gold and filver. Expofed to
the blow-pipe, the fide removed from the immediate
a£Hon of the flame, became blue. Expofed in an open
veffel to a greater degree of heat than the fufing tem¬
perature of gold, no appearance of fufion or oxidation
was obferved. When the heat was increafed, a melt¬
ed button wTas obtained, which had loft a little of its
weight, but was increafed in fpecific gravity. The
addition of fulphur renders it more fufible, and ex¬
tremely
CHE
Palladium, tremely brittle. There feems to be no a&ion between
, &Ct charcoal and palladium. Mr Chenevix found that
this fubftance formed alloys with gold, platina, filver,
copper, lead, and fome other metals. The alloy with
lead was the hardeft of all, but extremely brittle, and
its fpecific gravity was 12. He alfo fubje&ed this fub¬
ftance to other experiments, with alkalies, fome of the
earths, feveral of the acids, and fome of the falls; and
from the whole he concludes that it would be difficult
to fay of what metal, or of what combination of metals,
2r.0 palladium confifts.
h an alloy. 2. Mr Chenevix (till profecuted his experiments, and
he concluded at laft, that this fuppofed new metal is an
alloy of platina and mercury. It muft however, be ob-
ferved, that he did not arrive at this difcovery by ana-
lyzmg palladium, for he failed in every attempt with
that view. It was by combining platina and mercury
in certain proportions, that he compofed a fubftance
which he confidered as exa&ly fimilar in all its pro¬
perties to palladium. The procefs by which he fuc-
ceeded in forming palladium, or a fubftance exa&ly fi¬
milar, was by diflblving 100 grains of platina in nitro-
muriatic acid, and then adding 200 grains of red oxide
of mercury. This being infufficient to faturate the ex¬
cels of acid, more was added till it ceafed to be dif-
folved. A quantity of green fulphate of iron was then
poured into a long-necked matrafs, to which the mix¬
ed folution of platina and mercury was added, and the
whole placed upon a fand bath. In lefs than half an
hour, a precipitate formed, and the infide of the ma¬
trafs was lined with a thin metallic coat. The liquor
was palTed through a filter, and the precipitate, after
being digefted with muriatic acid, was well walked
and dried. The whole quantity colle&ed amounted
to 276 grains, which were compofed of 92 of platina,
and 184 of mercury. It was in the form of a fine
powder, with a metallic luftre. It w’as put into a
charcoal crucible, and fufed into a button. The fpe¬
cific gravity was n.2. It was entirely foluble in ni¬
tric acid, eafily fufed by fulphur, and precipitated by
green lulphate of iron ; thus exhibiting all the proper¬
ties of palladium, which Mr Chenevix concludes, is
compofed of two parts of mercury, and one of pla¬
tina.
Specific 3* One of the moft lingular circumftances with re¬
gravity re- garcl to this alloy, if fuch it can be called, is its fpeci-
markable. lie gravity, which is not only far below the mean of the
fpecific gravity of the two metals, but confiderably infe¬
rior to either of its elements. The fpecific gravity of pla¬
tina is 22, according to fome greater, and that of
mercury is nearly 14, and yet the fpecific gravity of
the compound is only 10.972, little more than the
half by calculation. But although we have no rea-
fon to doubt the accuracy and precifion of Mr Chene-
vix’s experiments, and although we are little difpofed
to place any confidence in the affertion of the unknown
difeoverer of this fubftance, from the extraordinary
circumftances under which it has been announced, yet
we do not confider the refult of thefe experiments fully
C99
fatisfaclory, in proving palladium to be an alloy of Palladium,
platina and mercury (k). Every attempt which Mr &c>
Chenevix made to analyze this luppofed new metal, fail- ^
ed. It is true, he was equally unfuccefsful in decompo-
fing the alloy of platina and mercury which he had form¬
ed, and which refembled palladium in moft of its pro- 2I;2
perties which were compared. The attempts which His experi-
have been made to repeat the experiments of Mr Che- mtnts not
nevix, have not fucceeded. No other chemift has yet
been able to form the compound of platina and mer- fadtory-
cury, which pofleffes the properties of palladium *. * pm.
Till, therefore, Mr Chenevix (hall have extended his Tranf.
refearches concerning this alloy, or till it ffiall have lSo3» P*
been examined by fome other chemift, we muft remain 250
in fufpenfe with regard to its nature. 2I
4. Two other metals have been juft announced. Iridmm,
They were difeovered in crude platina by Mr Ten¬
nant, in analyzing the black powder which remains
after diffolving platina. To the firft of thefe metals
Mr Tennant has given the name of iridium, from the
various colours it aflumes in folution. It pofieffes the
following properties. It is foluble in all the acids,
but lefs foluble in muriatic acid, with which it forms
ottahedral cryftals. The folution with much oxygen
is deep red ; with a fmaller proportion, green or deep
blue. It is partially precipitated by the alkalies, and
by all the metals except gold and platina. Infufion
of galls and pruffiate of potaffi deprive this folution of
its colour, but without any precipitate ; thus affording
an eafy left of its prefence. The oxide, therefore,
lofes its oxygen by Water alone. When combined
with gold or filver, it cannot be feparated by the
ufual procefs of refining thefe metals. The fame fub¬
ftance was examined by Def-coftils and Vauquelin, and
the properties which they aferibe to this metal are the
following. 1. It reddens the precipitates of platina
made by muriate of ammonia. 2. It is foluble in mu¬
riatic acid. 3. It is precipitated by the infufion of
galls and pruffiate of potafh.
5. The other new metal is obtained by heating theOfmxum.
black powder with pure alkali in a filver crucible.
The oxide of this metal combines with the alkali*
and may be expelled by an acid, and obtained by di-
ftillation, being very volatile. It does not redden ve¬
getable blues, but flains the fkin of a deep red or
black. The oxide in folution with water has no co¬
lour ; but by combining with alkali or lime, becomes
yellow. With the infufion of nut-galls it gives a ve¬
ry vivid blue colour. It is precipitated by all the
metals excepting gold and platina. An amalgam may
be formed with mercury, by agitating it with the
aqueous folution of this oxide. When this amalgam
is heated, the mercury is driven off, and the pure
metal remains behind^ in the ftate of black powder.
To this metal Mr Tennant has given the name of
ofmium, on account of the ftrong fmell of the ox-
lde/*, . , r , „ + NUbot.
buch is the account of thefe metals which w^e have Jour. viif.
received. Should a fuller detail reach us in time we p‘ IlS> &
4 T 2 fhall 220‘
M I S T R Y,
and Ta^Uelin h,aV.e thrown a conjea-ure that palladium is probably an alloy of pla-
xlviii xd85! neW metal dlfcovered m crude Platina h? Collet-Defcoftils and Mr Tennam. Mn!de Chitn,
700
C H E M
Component /hall not fail to lay it before our readers, either in an
Parts of appendix to this treatife, or under the names of the
the \tmo rr - - - --------
fphere.
metals themfelves, in the order of the alphabet, in the
' courfe of the work.
Chap. XV. Of the ATMOSPHERE.
The atmofphere is that invifible elaftic fluid which
furrounds the earth. Its phyfical properties, fuch as
denfity, elafticity, and preflure, have been long known j
but its compofition and conflituent parts muft be rank¬
ed among the difcoveries of modern chemiftry. In
the prefent chapter, we propofe only to take a fliort
view of the nature, conftitution, and changes of the
atmofphere, referving the full difcuffion of the latter
to meteorology, to which it properly belongs.
Sect. I. Of the Component Parts of the Atmosphere.
i. The air of the atmofphere was confidered by the
ancients as one of the four elements of which all bo¬
dies are compofed. The fame opinion was held by
all philofophers, previous to the difcoveries of modern
chemiftry. It was univerfally admitted to be a Ample
homogeneous fubftance, till by the difcovery of oxy-
of oxygen gen gas by Dr Prieftley, and that of azotic gas by
a^esa20tlc Scheele, it was fully demonftrated that thefe two
e ' fubftances are the chief ingredients in atmofpheric
air.
Phyfical 2l This compound poffeffes all the phyflcal properties
properties. different kinds of air which we have hitherto
examined. It is invifible, elaftic, and may be inde¬
finitely expanded and compreffed. The fpecific gravi¬
ty of atmofpheric air is 0.0012, or it is 8 £ 6 times light¬
er than water. A hundred cubic inches weigh 31
gains troy ; but in confequence of the elafticity of the
air, the abfolute weight and the denfity muft vary with
the temperature and preffure. The eftimation which
we have here given, is taken at the ordinary tempera¬
ture of the atmofphere, between 50° and 6o°, and when
the barometer, which indicates the preffure, Hands at
30 inches. The denfity muft vary by diminilhing, ac¬
cording to the height above the furface of the earth.
The experiments of naturalifts, whofe attention has,
been particularly diie&ed to this fubjeft, have (hewn
that the diminution of denfity is in the ratio of the
compreflion, and therefore, that the increafe of denfity
is in geometrical progreflion, while the heights increafe
2158 *n arithmetical progreflion.
Method 3* After the difcovery of the compofition of atmo-
of eftunat fpheric air, it became an objeft with philofophers to de-
portkm^0" teim’ne t'le ProPorti°ns °f its component parts. It
" ‘ ’ was obferved by Prieftley and Scheele, and other phi¬
lofophers who were occupied in the profecution of
their difcoveries, that a certain portion of a given quan¬
tity of atmofpheric air only was abforbed during the
proceffes of combuftion and refpiration. It was ob-
ferved too, that certain fubftances combined with the
portion of atmofpheric air which difappeared during
thefe proceffes, and that the fame quantity of atmo¬
fpheric air,, (uffered no farther diminution, whatever
length of time it was expofed to the a&ion of thefe
fubftances. The portion of the air abforbed is the oxy¬
gen gas, and on this principle is founded the conftiuc-
tion of thofe inftruments which have been denominated
215S
ts a com¬
pound
2156
I S T R Y.
eudiometers^ becaufe they are employed to meafure the Component
purity of a given portion of air, by afcertaining the Parts °f
quantity of oxygen gas which it contains. Different t^r,Atm0‘
eudiometers have been propofed for this purpofe, but ■ ,
all depending on the fame principle, namely the ab-
ftraftion of oxygen gas from a given quantity of air.
The reader will probably recolleft the effects which
take place by mixing together nitrous gas and the air
of the atmofphere, or oxygen gas. When thefe gafes
come into contaft, red fumes are produced; the
bulk of atmofpheric air is partially, and that of
oxygen gas almoft entirely diminilhed. This is owing
to the combination of the nitrous gas with the oxygen
gas, forming nitric acid, which, if the experiment be
made over water, is abiorbed ; thus diminifliing the
bulk of the air by the quantity of oxygen gas abftrac- ’
ted. This is the principle of the firft eudiometer, which
was propofed by Dr Prieftleyjj but it has been found
that the refults and experiments with this kind of
eudiometer are far from being uniform and conftant.
It is fubje£t to variation from the difference of purity
of the nitrous gas employed, the water over which the
experiment is made, and even the form and conftruc-
tion of the apparatus. The variations in the refults of
different experiments by different philofophers, are
from 22. to 30. of oxygen gas in 100 parts of atmofphe¬
ric air.
Scheele propofed a different eudiometer. A mix¬
ture of iron filings and fulphur formed into a pafte with
water, abforbs the whole of the oxygen gas of any
given portion of atmofpheric air. The diminution of
bulk of a portion of air, expofed to the aftion of this
fubftance, therefore, indicates the proportion of oxygen
gas which it contains 5 but this abforption goes on
flowly, and is therefore an objedlion to this mode of af¬
certaining the proportions of atmofpheric air. This
objedlion has been removed by an improvement of this
eudiometer, in which hydrogenated fulphuret of potalh
or lime is fubftituted for the iron filings and fulphur.
This is prepared by boiling together fulphur and lime
water, or a folution of potafh in water. By the ufe of
this fulphuret, the abforption takes place in a few mi¬
nutes. A given portion of air is agitated in a bottle
with this fulphuret, taking care to exclude the exter¬
nal air with a ground ftopper. The diminution of the
bulk of this quantity of atmofpheric air fhews the pro¬
portion of oxygen gas which it contained.
Volta propofed to explode a given portion of atmo¬
fpheric air with hydrogen gas, by means of the eleflric
fpark. The hydrogen and oxygen combine together
and form water •, and the diminution of the bulk of the
airs employed is in proportion to the quantity of water
formed. But to this method of afcertaining the quantity
of oxygen gas in a given portion of atmofpheric air, it
has been objefted, that the proportion of hydrogen gas
requires to be accurately adjufted ; for if it exceed, the
fuperabundant quantity increafes the bulk of the re¬
maining air ; and, if the proportion be too fmall, the
oxygen and azote will form nitric acid by the aftion of
eleftricity, and thus the refiduary quantity of air will
be too much diminilhed.
When phofphorus is expofed to the air, it abforbs the
oxygen readily, and is converted into phofphorous
acid. This, wdiich was firft propofed by Achard, has
been improved by Berthollet, for the purpofes of a eu¬
diometer.
t
CHEMISTRY.
701
the A.tmo-
fphere.
Component diometer. A given portion of air is expofed to the ac-
Parts of tjon 0f phofphorus, in a veflel over water ; when the ab-
forption has ceafed, the remaining air is meafured, the
diminution of which indicates the quantity of oxygen
gas which it contained.
Mr Davy has propofed the green fulphate or muri¬
ate of iron diifolved in water, impregnated with nitrous
gas. This folution is prepared by tranfmitting nitrous
gas through green muriate or fulphate of iron diffolved
to faturation in water. All the *apparatus neceffary is
a fmall graduated tube, having its capacity divided in¬
to too parts, and greateft at the open end, and a vef-
fel for containing the fluid. The tube is filled with
the air to be examined, and then introduced into the
the folution. To promote the abforption, it is gently
moved from a perpendicular to a horizontal pofition.
In a few minutes the experiment is completed, and the
whole of the oxygen condenfed by the nitrous gas in
the folution, in the form of nitric acid. But in this
procefs it is neceflary to obferve the period at which
the diminution flops, for after this the volume of refi-
dual gas is increafed by the decompofition of the nitric
acid, by means of the green oxide of iron*.
From a number of comparative experiments made by
Mr Davy, with different eudiometers, and from other
experiments on air in different places, and colle&ed
under different circumftances, it appears, that the com¬
ponent parts of atmofpheric air are always nearly the
fame. Thefe proportions are from .21 to .22 of oxy¬
gen gas, and from .78 to .79 of azotic gas. The con-
ftituent parts, therefore, of atmofpheric air by bulk
may be taken at
Oxygen gas 22
Azotic 78
* 'Jour.
Hoy. Injl,
i. p. 45.
2^9
Compoli
tion.
But In eftimating the proportions of given bulks of
atmofpheric air, it is neceffary, as we have already
hinted, to take into account the denfity and tem¬
perature, otherwife very great anomalies muft hap-
2160
Water.
pen.
4. It is univerfally admitted, that water exifts in the
atmofphere ; but philofophers are greatly divided with
regard to the quantity of water, and the ftate in which
it exifts in the air. To afcertain the quantity of wa¬
ter, inftruments called hygrometers, or meafurers of moi-
Jlure, have been contrived ; the quantity of which is
indicated by certain changes which take place by its
abforption ; but none of thefe inftruments that have
yet been invented are fufceptible of great accuracy,
and perhaps to this is owing the very different refults
in eftimating the quantity of water in the atmofphere.
There is alfo a very great difference of opinion
whether this water exifts in the atmofphere in the ftate
of water, or whether it has been converted into va¬
pour. According to the firft opinion, the water is
ai<Ji held in folution by the air, and the quantity increafes
In the ftate as the temperature of the air is increafed. But accord-
of vapour. Jng t0 others, the water of the atmofphere is in the
ftate of vapour. According to the experiments of
naturalifts, the quantity of water in the atmofphere
varies in different climates, and at different feafons of
the year from to part of the weight of the at-
mofphere.
5. When lime-water, or an alkaline folution is ex- Conftitu-
the air, it is foon covered with a cruft or tl0ri ot
the Atmo-
fphere.
pofed to the air,
pellicle. This is owing to the abforption of carbonic
acid, and the converfion of the alkali or lime to the
ftate of carbonate. This ftiews that carbonic acid 2I(j2
gas exifts in the atmofphere. This gas has been found Carbonic
not only on the furface of the earth, where the denfity acid gas.
of the atmofphere is greateft, but alfo on the tops of
fome of the higheft mountains. The quantity of car¬
bonic acid gas in the atmofphere is fuppofed to vary
from .ci to .005 part.
Sect. II. Of the Constitution of the Atmosphere.
2163
1. The component parts of the atmofphere are, Different
azotic gas, oxygen gas, water, and carbonic acid gas. opinions.
Here a queftion has arifen among philofophers, whether
thefe parts are chemically combined, or merely form a
mechanical mixture. According to one fet of philo¬
fophers, the oxygen and azotic gafes of the atmofphere
are in chemical union, beeaufe their proportions are
always found to be uniform and conftant, which it is
fuppofed could not be the cafe from the inequality of
the caufes a6ting in diminilhing the quantity of oxygen
gas, by the different proceffes of combuftion and re-
fpiration, which are going on in the furface of the
earth, if the component parts of the air were not in 2164
chemical combination. The air of the atmofphere ^n c^em'"
too, it is faid, poffeffes properties very different fromCtt uruon’
the artificial mixture of its component parts. The
proceffes of combuftion and refpiration continue for a
greater length of time in the latter, becaufe it parts
with a greater proportion of its oxygen, and for the
fame realbn it is more diminifhed by nitrous gas. Ac¬
cording to others, the air of the atmofphere is merely
a mechanical mixture. This opinion is fupported by
Mr Dalton, in fome ingenious fpeculations on the con-
ftitution of mixed gafes, and particularly of the at-
mofphere. The principle on which Mr Dalton’s hy- viechani-
pothefis is founded is, that the particles of homogene- '-al mix-
ous elaitic fluids only mutually adft upon each other,ture’
and that the particles of an elaftic fluid of one kind are
neither attradled nor repelled by the particles of an
elaftic fluid of a different kind, wdien they are mixed
together. According to this hypothefis, therefore, the
particles of the oxygen gas of the atmolphere mutually
aft on each other, or are only attrafted and repelled
by thofe of their own kind *. * See
2. A difference of opinion alfo prevails, whether
the vapour of water, as it exifts in the atmolphere, be-^”’'v0^v*
merely a mechanical mixture, or chemically combin¬
ed. The former opinion is alfo fupported by Mr
Dalton, upon the principle that all gafes mixed with
vapour, expand in a proportional degree to the elafti-
city of the vapour in that temperature.
Sect. III. Of the Changes of the Atmosphere.
2166
I. The changes which are produced in the atmo-Tempera-
fphere by heat and cold, are too obvious to efcape ob-ture*
fervation ; but it was not till the invention of the
thermometer that thefe changes could be obferved and
marked wdth any degree of accuracy j and even after
the invention and improvement of this inftrument, it
was long before any feientific application wTas made of
the
^02
Changes
of the At-
mofphere.
Th( fun
the fource
of heat.
2168
Fixed
points of
tempera¬
ture im¬
portant.
2I(>9
Annual
tempera-
ture. '
G H E M
the changes of the temperature which it indicated.
The variable temperature of the fame day, the great
difference between midnight and midday, and the ftill
greater difference between the heat of fummer and the
cold of winter, feem to hold out a number of infulated
fails, without refemblance or connexion, and incapa¬
ble of being arranged under any general law. But
more comprehenfive views, and more extended obfer-
yations, have not only fhewn the poflibility of eflablifh-
ing a general principle, but have enabled philofophers
to. arrange and claffify phenomena which were other-
wife feemingly unconnected.
2. The great fource of heat is the fun. This is
fully demonftrated by the increafe of temperature be-
ing in proportion to the duration and greater or lefs
obliquity of the fun’s rays. It has been imagined that
the earth is heated by central fires : but this opinion
feems to be fully difproved by obferving that the tem¬
perature depends invariably on the abfence oi' prefence
of the fun $ that this temperature is diminifhed, at
leaf! to a certain extent, by going deeper into the
eartn ; and that the cold is greateft in places moll di-
ftant from the fun’s rays ; fo that the temperature
which is. moft uniform within the tropics, diminifhes,
other things being equal, in proportion to the diftance
from the equator towards the poles.
3. In confidering the difference of temperature
which.is obferved in different places, it became an ob¬
ject with, philofophers to difeover fome fixed points
from which the whole amount of the changes for any
given period could be afeertained. This was firft
thought of by Mayer, who propofed the method ufed
by aftronomers, of finding the mean of certain large
penods, as for years and months j and he made the
i dcovery by which the mean annual temperature of
two latitudes being known, the mean annual tempera-
ture for every other degree of latitude may be alfo
round. I he application of this rule has been greatly
improved and extended by Mr Kirwan, and upon this
principle he conffrufted tables which exhibit the mean
annual temperature for all degrees of latitude from the
equator to the poles. Thefe tables were conftruaed
by finding from obfervation the temperature of what
rn T Va f\tuation> that is> a place lefs liable
to he affeaed by adventitious caufes, but where the
caufe of temperature, or the communication of heat
W hea-rOUrCe’ Jwa^moft unif°nn and conflant ; and
having difeovered tins ftandard fituation, to compare
the temperature ot every other fituation with it. The
rand Mr. Kirwan thought, owing to the operation of
caufes which occafion variations lefs eafily appreciable
would not afford refu]ts fufficientl JfJ?
fituation, he then concluded, was to be fought for on
e CI> and Jhat Part of the ocean which he chofe
was the tmmenfe traft of water which includes that’
part of the Atlantic lying between the 8o° of north
ward^’f31^ the!450 °f f°Uth latitude> extending weft-
Lfues orthr g,UlI ftre.am’ arid -ithiif a few
hegpl/ COaft°f1^raeiica’ and a11 ^t part of
i the 4o=Cfouthni FrCd,ng the 45° north latitude
to tne 40 fouth latitude, and from the 20° to the 2-c0
g e “fpatofl ^7 London. Thi, include,
greater part ot the furface of the odnh° f .n
method of conilruaing thefe tablesf and' for 1 «£
I S T R Y.
themfelves, we refer our readers to the article Mete- Changes
orolooy, where they will be inferted. of the At-
The difference of temperature, it may be obferved im°fo-?iere-
wdthin io° of the equator and within the fame diftance
from the poles, is very fmall, and the variation of tem-
rature for different years within-the fame fpace, is alfo
found to be very little j but as the diftance increafes
from the equator towards the poles, the difference of
temperature is greater. In latitudes under 35% it
fcarcely ever freezes,.excepting in very elevated fitua-
tions, and it fcarcely ever hails in latitudes higher
than 6o°. In places near the lea, between the lati¬
tudes of 350 and 6o°, it generally thaws when the fun’s
altitude is 40°, and feldom begins to freeze till the me¬
ridian altitude be below 40°.
4. Mr Kirwan has ali'o conftru&ed tables to mark Month.*,
the mean monthly temperature. In every latitude
the mean temperature of the month of April ap¬
proaches nearly to the mean annual heat of that lati¬
tude. And from this analogy he proceeded, fuppofing
that the temperature is always regulated by the diredl
aftion of the folar rays, unconneded with other circum-
ftances which occafion confiderable variations. Tak-
ing all thefe into the account, and endeavouring to
reduce them to ftrid calculation, he found it impradi-
cable ; and therefore he conftruded his tables, partly
from principle, and partly from the belt obfervations
he could procure from fea journals, and fimilar fources
of information. The mean monthly temperature in
thefe tables alfo refers to the ftandard ocean.
The coldeft weather prevails about the middle ofColS*
January in all climates, and the warmeft in fuly $ but feafon.
if it depended immediately on the fun’s heat, the
greateft heat ftiould prevail in the latter end of June, w "S
and the greateft cold in the latter end of December.
But as the earth requires a confiderable time to ab-
forb heat, fo alfo it is fome time before what has been
abforbed is given out. All thefe obfervations and cal¬
culations refer to.the furface of the ocean, which is
lefs fubjed to variation from caufes, the influence of
which could not be afeertained with precifion.
6. But as the earth is the chief fource of heat in The elk
the atmofphere that furrounds it, the temperature muft heats the
decrease with the elevation above the earth, and inatrno_
the higheft regions of the atmofphere, where the air ^here'
is perfedly free from clouds, the greateft cold muft
prevail. Hence, in confequence of this elevation
above the level of the ocean, the higheft mountains
even under the equator, are covered with perpetual
How. Mr Bouguer found the cold on the top of
I mehmea in South America, immediately under the
line, to vary from 70 to 9° below the freezing point
every morning before, funrife, and hence at a certain
height which varies in almoft every latitude, it con-
ftantly freezes at night in every feafon ; although in
iome latitudes,, in the warmer climates, it thaws next
day. This height he calls the lower term of conge¬
lation, and he places it at the height of 15.577 be-
tween the tropics. In latitude 28° he thinks it ftiould
commence in fummer at the height of 13,440 feet
above the level of the fea. But at ftill greater heights
it never freezes at all, becaufe the vapours do not af-
cend fo high. This height Mr Bouguer denominates
the upper term of congelation; and immediately under
the
Changes
of the At
mofphere,
2174
Land and
water dif¬
ferent in
tempera¬
ture.)
2175
Tempera¬
ture varies
according
to the
height of
places.
C H E M
tlie equator he fixes it at 28000 feet. As the weather
is not fubjeft to great variations under the equator,
, the height of both thefe terms is nearly con-
flant, but in other latitudes this height is variable,
both in fummer and winter, in proportion to the de¬
gree of heat which prevails; and as there is a mean
annual temperature peculiar to each latitude, fo is
there a mean height for each of thefe terms peculiar
to each latitude. By taking the differences be¬
tween the mean temperatures of every latitude, and
the point of congelation, it will appear that whatever
proportion the difference under the equator bears to
the height of either of thefe terms, the fame proportion
will the difference peculiar to every other latitude bear
to their height.
7. But there is not the fame uniformity or capacity
m air, land, and -water, for receiving and returning
heat. Hence arife very confiderable deviations in the
temperature of places, as they are more or lefs connec¬
ted with thefe bodies. Air, when it is perfe&ly tranf-
parent, receives very little heat from the rays of the
fun as they pafs through it. Air w7hich is over feas or
large tradls of water, is generally many degrees warm¬
er in winter, and colder in fummer, than air which is
incumbent on land, becaufe the land receives the heat
much more readily than the water; in general the air
participates of the temperature of thofe fubftances with
which it is in contadf. Land, if dry, receives heat
rapidly, but tranfmits or condu&s it to great depths
very flowly; but water receives it more flowly, and
diffufes it more rapidly. From experiments made by
Dr Hales, it appears that the earth is much heated
during the fummer, but that this heat defeends very
flowly, great part of it being communicated to the airj
that during winter, the earth gives out to the air the
heat it had received during the fummer, and that wet
fummers muft be fucceeded by cold winters, becaufe
the heat is carried off by the greater proportion of eva¬
poration during the wet feafon. At the depth of 80
or 90 feet below the furface of the earth, the tempera¬
ture is found to vary very little, and it generally ap¬
proaches to the mean annual heat. The temperature
of the cave at the obfervatory of Paris, which is 90
feet below' the pavement, is about 53.50. The great-
eft variation which has been obferved, does not exceed
half a degree, and this only happens in very cold
years. Hence, too, the temperature of fprings is al-
moft uniformly the fame throughout the year, and cor-
refponds with the mean annual temperature of the cli¬
mate.
8. There is not only a confiderable difference in the
temperature of land and water ; but this variation alfo
holds with regard to the land itfelf, according as it
is elevated above the furface, and according to the na¬
ture of the furface, whether it is covered with vege¬
tables, or only exhibits bare rocks, or fterile fand. A
confiderable deviation alfo is obferved to take place,
in proportion to the diftance from the ocean. All
thefe caufes, how'ever, are greatly modified by the re¬
lative fituation of places with regard to feas and oceans,
mountainous regions, and extenfive trafts of level
country covered with thick forefts, or improved by
cultivation. Thefe caufes too are modified by parti¬
cular winds, which produce confiderable deviations, as
I S T R Y. 703
they proceed from the ocean, from low, flat countries, Changes
or elevated regions. of the At-
9. Another remarkable change to which the atmo- ,m°^lere-,
phere is fubjecl, is the difference of its weight or pref-
fure. The air, like all other matter, is influenced byp ^
the law of gravitation, by which it preffes with a cer¬
tain force on the furface of the earth. It has been
ound that the meafure of this force is nearly equal to
lylb. on every iquare inch. The variations which
take place in the atmofphere are meafured by the baro¬
meter. The mercury in the barometrical tube is fup-
ported by a column of air of an equal bafe, and fince
this column of air and the mercury in the tube mutual¬
ly balance each other, it follows that they are of the
fame rveight, and therefore the barometer may be em¬
ployed as a meafurer of the weight or preffure of the
air.
10. 1 he firft general fa<ft with regard to the weight fame
of the atmofphere is, that in all places at the level of the ;evel
the fea, the barometer ftands nearly at the fame point °*the ^
and the mean height is about 30 inches. But as the
elevation is increafed, the barometer finks, becaufe then
there is a ftiorter column of air to fupport it, which is
therefore lighter. In no place does the weight of the
air continue always the fame. It is fubjeft to daily
variations, which are greater or fmaller according to
the latitude of the place, or the influence of particular
caufes. In all places within the tropics, the variations
of the barometer have been obferved to be fmalleft, and
in elevated fituations the variations are confiderably
fmaller than on the level of the fea. The deviations
of the mercury from its mean annual altitude are more
frequent and extenfive in the neighbourhood of the
poles than in that of the equator, and they are greater
and more frequent without the tropics in winter than
in fummer.
it. The caufes which have been propofed to ac-Caufe!
count for thefe variations, are changes of temperature
velocity of winds, and the agency of vapours. The
air is fubjeft to the adfion of heat, by which it is rare¬
fied or condenfed, according to the increafe or diminu¬
tions of temperature. Denfe air is heavier than that
which is rarer j but if the maffes of air remain the
fame, the weights muff be the fame, and confequently
the heights to which they elevate the mercury will be
alio equal. If, therefore, a change of temperature oc-
cafion a variation of the barometer, it muft be by in-
creafing or diminifhing the mafs of the atmofphere.
But it appears from obfervation, that a variation of the
mais of the atmofphere is not a neceffary confequence
of a change of temperature, for the mercury is often at
the fame height at different feafons, and at different
places at the fame time, when the difference of tempe¬
rature is very great. But even when the mercury
changes with the temperature, this variation is often
directly contrary to what it ought to be. The baro¬
meter has fometimes rifen with an increafe of tempera-
ture, inftead of falling by the rarefafHon of the air.
I he changes of temperature are very inconfiderable
m the higher regions of the atmofphere, fo that it
would appear that the barometer can be little affeaed
y changes of temperature. Mr Kirwan has endeavour¬
ed to fliow, that the influence of winds, or a greater or
Imaller quantity of vapours exifting in the atmofphere,
can
ai79
Winds.
704 C H E M I
Changes can have little effe<5i: in elevating or depreffing the ba-
efihe At- rometer# According to Mr Kirwan, the variations of
■ 1 '>^erc‘ the barometer, or the difference of preflure of the air
of the atmofphere, can only be accounted for from an
accumulation of air over thofe places in which the mer¬
cury exceeds its mean height, and from the diminution
or fubtraftion of the natural quantity of air, over thofe
regions in which the mercury falls below its mean
height.
1 a. The winds conftitute another remarkable change
in the atraofphere. The winds in general are fubjedi to
great irregularity j but in fome parts of the world they
are pretty regular and uniform. Between the 30° of
N. Lat. and the 30°of S. Lat. the wind, when it is not
counteracted by local caufes, continues to blow conftant-
ly from the fame points. On the north fide of the equa¬
tor, that is, from the equator to the 30* of N. Lat.
it blows from the north-eaft, and from the equator to
the 30° S. Lat. it Blows from the fouth-eaft. This
is called the trade-wind. Immediately under the equator
the wind is obferved to be pretty nearly from the eaft $
that is, about the place where the two currents meet,
the one from the north eaft, and the other from the
fouth-eaft ; but receding from the equator, the direc¬
tion df it deviates more and more from the eafterly
point, till it reaches the intermediate point beween
north and fouth, and then conftitutes the north-eaft:
trade-wind on the north fide, and the fouth-eaft trade-
wind on the fouth fide of the equator. Were the
caufes which produce this conftancy and uniformity of
the trade-winds uninfluenced by others, thefe winds
would prevail without variation within the limits or
near the boundaries of the torrid zone : but they are
greatly counteracted, and fubjeCt to great variations,
from the unequal influence of land and water, in rare¬
fying or condenfing the air.
13. As the air of the atmofphere is a fluid body, and
therefore fubjeft to all the laws of fluids, if any part
be removed, the remainder rufhes in to reftore the
equilibrium, and hence an agitation or wind is produ¬
ced, as air is capable of indefinite dilatation and com-
preflion. The denfer air being heavier, muft fink, and
the rarefied air afcends, when air of unequal denfities is
mixed together. The greateft degree of mean tempe¬
rature is within the torrid zone, in confequence of the
fun’s rays being more perpendicular, and aCling with
greater force on the earth’s furface. The air there¬
fore round the equator undergoes the greateft degree
of rarefaCtion, and this extends to the north and fouth,
in proportion to its diltance from the equator, or ra¬
ther its diftance from the fun’s place. Thus, when the
fun is perpendicular to the equator, or middle part of
the torrid zone, the air in that place being molt rare¬
fied, becomes lighter, afcends, and its place is filled
with the colder air from the north and fouth. And thus,
as long as the fun’s influence continues to rarefy the air,
would a north and fouth wind blow to that quarter
where the rarefied air, being rendered lighter, had af-
cended. Lut as the earth has a diurnal motion on its
axis from weft to eaft j thofe parts of the earth’s fur-
face to the weftward are firft heated, and confequently
the incumbent air is firft rarefied. The denfer air
from the eaft muft therefore rufh in to reftore the equi¬
librium. Thus, there is produced an eafterly wind/
But there is another current of air from the north and
2180
Trade-
winds.
S T R Y.
fouth : the two currents coming from the north-eaft: Waters,
trade-wind on the north fide of the equator, and the "V f
fouth-eaft trade-wind on the fouth fide.- Such are the
caufes which are generally fuppofed to produce the re¬
gular trade winds. 2igr
14. Thefe winds are regular and uniform in open DeViaUon5(
oceans, fuch as the Pacific or Atlantic, but they
are fubjeCf to confiderable variation from the unequal
rarefaCfion of the air over land and water. Thus,
iflands fituated within the very courfe of the trade-
winds have regular land and fea breezes, which are of¬
ten direCtly contrary to the trade wind. In confe¬
quence of the air incumbent on the land being more
rarefied during the day, the wind blows from the lea,
conftituting the fea breeze ; but the air over the fea
being warmer during the night, the wind blow’s from
the land, from which it is called the land nvind. To a
fimilar caufe is owing another remarkable deviation
from the uniformity of the trade winds, which is ob¬
ferved in the great Indian ocean. Here the winds 2Iga
called monfoons blow from one quarter during fix Monfoons.
months of the year, and from an oppofite diredion
during the remaining fix months. While the fun is in
the northern tropic, the air over the extenfive Indian
continent is greatly rarefied; and, in confequeHce of
this rarefaClion, the denfer air from the ocean rufhes
in to reftore the equilibrium, and hence the current of
the air or wind continues during this period of the
year, conftituting the fouth-eaft monfoon. But when the
fun pafles the equator to the fouthward, the air over
the fouthern hemifphere is more influenced by his rays,
and therefore more rarefied. The denfer air then
rufhes in from the north, and thus produces the north-
weft monfoon, wdiich blows during our winter, when
the fun is in the fouthern tropic. 2lg
15. But even a fuperficial obfervation will {hew, that part of the
the phenomena of the winds cannot be fatisfaftoiily ac- air fuppof-
counted for, merely upon the general principle of the ed to be
unequal rarefaClion of the air over land and water.abftra<ae®*
Thus, hidden changes of wind often happen in particu¬
lar places, which are extremely limited, and altogether
unconneCled with the difference of denfity of the air
over land and water. The hurricane has fwept the
land, whofe effeCls have not been felt on the neigh¬
bouring ocean, and the ftorm frequently agitates the
ocean without reaching the land. Thefe and other
phenomena of the winds, equally inexplicable, have
been afcribed by naturalifts to the abftraClion or hid¬
den deftruCtion of a certain quantity of the air of the
atmofphere in particular places. But for the full dif-
cuflion of this fubjeCl and the other phenomena' of
the atmolphere, we muft refer our readers to Meteo¬
rology.
Chap. XVI. Of WATERS.
I. We have already treated of the component parts of
water, of the difcovery of its compofition, and of its mofl:
remarkable properties; and efpecially thofe which it ex¬
hibits by a change of conftitution, as in the folid ftate
or that of ice, in the liquid ftate, and in the ftate of
vapour. In thefe views water was confidered as per¬
fectly pure ; but this is rarely or never the cafe, as 2Ig4
it is found in nature. Rain water, which is the pureft, \yat<r not
is not entirely free from imptegnation, even when col-found pure.
leCted
C H E M
Sea-water, lecied before it falls to the earth. It Is flightly con-
taminated with certain fubftances, which it held in
folution, as it exifted in the clouds, or with which it
combined in its pafiage through the atmofphere. But
waters as they flow on the furface of the earth, or are
carried through the ftrata under the furface, muft dif-
folve thofe foluble fubftances wuth which they come in
contaft. It is the object of our prefent inveftigation
to examine the waters as they are found in nature, and
tne fubftances with which they arc impregnated.
^ 2. 1 he properties of pure water are almoft obvious to
the fenfes, fo that few fubftances, at leaft in any quan¬
tity, can be diflblved in water, without being eafily re¬
cognized. Thus, the faline, naufeous tafte of fea-wa-
ter, the fetid odour, or the aftringent tafte of mineral
SS185 fpnngs> niuft readily be diftinguifhed by thefe ftriking
Can only be qualities. But although it is probable that the re-
bydiemf- mar^able diverfity of waters, from their obvious pro-
cal agents. Pfrt‘e®> could not fail to be early obferved by man¬
kind, it is only by chemical inveftigation that the na¬
ture of the fubftances to which they owe thefe proper¬
ties, can be afcertained 5 and indeed vve are indebted
to. the difcoveries and improvements of modern che-
miftry for the knowledge which w7e poflefs of the na¬
ture and proportion of the ingredients which enter
into the compofition, either of fea w7ater or mineral
fprings.
This fubjeff has been particularly inveftigated by
Bergman, Weftrumb, Black, Fourcroy, Klaproth, and
Kirwan. In the three following feftions we propofe to
treat, x. Of fea-w7ater 5 2. Of mineral waters j 3. Of
the method of analyzing them.
S186
Properties.
2187
Salts.
2188
Proportion
vanes.
Sect. I. Of Sea -WATER.
1. The faline tafte of fea-w7ater, w7e have already
cbferved, could not fail to make it be diftinguiftied
iiom pure .water j and this tafte, it is well know'n, is
chiefly derived from common fait which it holds in
foiution. Sea-W7ater is alfo diftinguiftied by a naufeous
bitter tafte, which is afcribed to the animal and vege¬
table matters wTich are floating in it. This tafte has
been confidered as in fame meafure foreign to it ; for
it is only found in the water on the furface of the ocean
or near the fhores. Sea-water taken up at confidera-
ble depths, contains only faline matters. The fpecific
gravity of fea-w7ater varies from 1.0269 t0 i-OiSy.
Its greater dcnfity is owing to the falts which are
diffolved in it; and to this impregnation alfo it is owing,
that it is not frozen till the temperature is reduced
nearly to 28°.
2. The falts which are chiefly found in fea water,
are muriate of foda, or common fait, muriate of mag-
nefia, fulphate of magnefia, fulphate of lime and fo¬
da. The quantity of faline ingredients in the waters
of the ocean varies from to T*T part. Mr Kiman
makes the. average quantity about ^ of its whole
weight. The quantity of faline contents of w7ater,
taken up by Lord Mulgrave at the back of Yarmouth
fands, in latitude 53°, amounted nearly to -yV ; wLile
Bergman found the water taken up in the latitude of
the Canaries to contain about of its weight of faline
matter. . Thefe quantities, however, vary, even in the
fame latitude, during rainy and dry feafons, near the
land, or the mouths of -great rivers. The difference
Vol. V. Part II.
I S T R Y; 70s
of latitude does not feem to make any confiderable dif- Sea-water,
ference in the proportion of faline matter. In latitude v—^
8o° north, 60 fathoms under ice, fea water taken up
by Lord Mulgrave, yielded about ^ ; in latitude
74° nearly the lame; and in latitude 6o°, -%•§. Pages
o jtained four per cent, from wat r taken up in latitude
8i°, and the fame quantity of faline matter from wa¬
ter taken up in latitudes 450 and 390 north. In
fouthern latitudes, the proportion was Hill greater; he
found it to contain the following proportions: ai8p
Lat. 490 50' S. 4.1660 per cent, of faline matter. fri.fou,them
- latitudes.
4-5
4
4
3-9
3-5
In the Mediterranean the proportion is faid to be
ftill greater ; but the Euxine and Cafpian feas are
found to be lefs fait than the ocean. This alfo is the
cafe with the Baltic. If the faline matters of the wa¬
ters of the ocean did not confift of different kinds, the
proportion of falts which it contains might be afcertain¬
ed by the fpecific gravity. In the following table the
fpecific gravity of fea water taken up in different lati¬
tudes has been determined by Mr Bladh. The tem¬
peratures are reduced by Mr Kirwan to 62° of Fahren¬
heit ; and the longitude is reckoned by Bladh from
Teneriffe.
46° 00'
4°° 3 o'
28° 54'
2 0° OO'
1° l6'
2T$0
Specific
gravity i»
different
latitudes.
yo6
Sea-water.
2191
In the Bal¬
tic.
From this table it appears that the proportion of fa-
line matter is greateft near the tropics; and the fmaller
quantity near the equator is afcribed to the great
quantity of rain that ufually falls on that part of the
globe.
3. The experiments of Mr Wilcke flrow that t’i«c
proportion of faline matter in the Baltic is lefs than
that of the ocean ; and that it is falter during the pre¬
valence of a wefterly wind, by which the water is driven
from the ocean, than during an eafterly wind. The
following is the fpecific gravity of the waters of the
Baltic, taken during the prevalence of different winds,
and reduced by Mr Kirwan to the temperature of 62°.
Wind. Specific gravity.
Eaft, 1.0039
Weft, 1.0067
Weft, a ftorm, 1.0118
North-weft, 1.0098
\
From this it appears, that the proportion of faline
matters in the Baltic is increafed by the influx of wa¬
ter from the ocean, and is confiderably influenced dur¬
ing a ftorm, when the wind blows from that quar¬
ter.
4. Dr Watfon has eftimated the quantity of fait in
water of different fpecific gravities. It is alfo reduced
to the temperature of 62° by Mr Kirwan, as in the
following table.
CHEMISTRY.
a-
Sect. II. Of Mineral IVaters.
Salt.
2 s
I
W
I
X
•eF
I
To
1
TIT
1
T3
T
TT
1
1 oT
Specific gravity.
I.0283
I.0275
I.0270
I.0267
I.0250
I.0233
1.0185
I.OO33
I.OIO5
1.0040
I.OO23
Thefe experiments were made with folutions of com¬
mon fait, which was not perfe&ly pure, and therefore
it is allowed that they may correfpond pretty nearly
with the proportions of faline matter in fea-water of
the fame fpecific gravities.
Proportions. 5* ^ proportions of the different falts in an ana-
lyfis by Bergman, are the following.
Muriate of foda 30-911
Muriate of magnelia 6.222
Sulphate of lime 1.000
38-I33
In 1000 parts of water taken up near Dieppe, Lavoi-
Her found the following falts.
Muriate of foda
- ■ ■' ■ ■ of lime and magnefia
of magnelia
Lime
Sulphate of foda and magnefia
*375
256
*56
87
84
J958
Mineral
Waters.
I. The name of mineral waters has been given tof;j1^r^er,
thofe waters which are diftinguiftied by the fmell,
tafte, or colour, from pure water $ the obvious pro¬
perties of which are, tranfparency and infipidity.
Thefe peculiarities of tafte, fmell, and other proper¬
ties, are owing to the impregnation of certain mineral
lubftances which they have acquired in their paffage
through the foil or ftrata of the earth. The effedts
which fuch waters produce on the animal economy, ,
early attra&ed the attention of mankind, and led to
their application as remedies in the cure of difeafes.
It was long indeed before any other diftimftion of mi¬
neral waters wras made, except what was indicated by
their fenfible qualities, and their effects on the human
conftitution. From thefe properties mineral waters
have been divided into four claffes : 1. Acidulous orClafies.
gafeous wraters ; 2. Saline waters ; 3. Sulphureous or
hepatic w7aters j and 4. Chalybeate waters.
1. Acidulous waters are diftinguilhed by their pene-Acidulous*
trating acid tafte, the facility with which they boil j
by fparkling when they are poured into a glafs $ and
by the emiffion of bubbles of air, by agitation. The
acid w'ith which they are impregnated is generally the
carbonic. Thefe waters redden the timfture of turn-
fole, and precipitate lime-w7ater. 2I^<-
2. The fecond clafs, or the faline waters, are fuffi-Saline,
ciently charafterized by their tafte, which varies ac¬
cording to the nature of the fait with which they are
impregnated.
3. The fulphureous or hepatic waters are at once Sulphure-
recognized by their fetid odour, and by blackening ous.
fome metallic fubftances, as lead and filver. Some of
thefe waters are impregnated with fulphurated hydro¬
gen gas, while in others it is combined with lime, or
with an alkali.
4. The fourth clafs, or the chalybeate waters, are Chaly-
diftinguilhed by an aftringent tafte. With the prufli-ber¬
ate of lime they give a blue colour, or a black with
the infufion of nut galls. This property is owing to a
portion of iron which is held in folution, either by
carbonic or fulphuric acid. Sometimes carbonic acid
is in excefs, and then the water has a penetrating
flightly acid tafte.
2. The fubftances which have been found in mine-Subftance*
ral waters, as they have been enumerated by Mr Kir-foVnd in
wan, belong either to the clafs of gafeous bodies, acids,mineral
alkalies, earths, or falts. waterS-
3. Oxygen gas was firft difcovered in waters byGafe^C®
Scheele. Itjps generally in fmall proportion, and does not
exift in waters with fulphurated hydrogen gas, or iron,
becaufe it is incompatible with thefe fubftances. Azo¬
tic gas has been found in the wTaters of Buxton, Har-
rowgate, and Lemington Priors. Common air was
firft difcovered in mineral waters by Mr Boyle ; the
quantity fcarcely exceeds of the bulk of the water.
Fixed air or carbonic acid was firft difcovered in Pyr-
mont wTaters by Dr Brownrig. The proportions are
very variable j but there are few mineral waters which
are entirely free from it. A hundred cubic inches of
moft waters, contain from 6 to 40 of carbonic acid
gas. A hundred cubic inches of Pyrmont waters con¬
tain, according to Bergman, 95 of fixed air j accord¬
ing
c H E M I
220t
Acids.
2201
Alkalies.
lies
Harths.
2104
Salts.
Mineral ing to Dr Higgins, 160, and according to Weftrumb,
Waters‘ , IBy cubic inches. Sulphurated hydrogen gas is the
principal ingredient in fulphureous or hepatic water.
Carbonated hydrogen gas is faid to have been dete&ed
in fome mineral waters in Italy.
4* Dhe next clafs of fubitances found in mineral
waters, are tne acids. Sulphuric acid has never been
found, except in combination with other fubftances,
forming falts in mineral waters. With fome of thefe
falts it exifts in excefs. Sulphurous acid has been de-
te6led in many of the hot mineral fprings in Italy, in
the vicinity of volcanoes. Muriatic acid has only been
found in mineral waters, in combination with other
fubflances. Nitric acid is faid alfo to exift in mineral
waters in Hungary, in a combined ftate. Boracic acid
has been found in a feparate ftate, in fome lakes in
Italy.
5* The alkalies are rarely found uncombined in mi¬
neral waters. In the ftate of carbonate they are fre¬
quent. Soda only was dete&ed in the hot mineral
fprings of Iceland, by Dr Black.
6. Few of the earths, except in combination, have
been found in mineral waters. Lime, it is faid, exifts
Uncombined in fome waters $ but Bergman obferves
that it muft be in hot, and not in cold mineral waters.
Dr Black dete&ed filica in the waters of Geyfer and
Rykum in Iceland. It has been found in thofe of
Carlfbad by Klaproth, and it has not unfrequently
been obferved by others in different mineral waters.
7. Tne falts which have been found in mineral
waters, are fulphates, nitrates, muriates, and carbo¬
nates.
Sulphates.—Sulphate of foda is frequently found in
the waters of fprings and lakes. Sulphate of ammo¬
nia has been found in mineral waters, in the neigh¬
bourhood of volcanoes. Sulphate of lime is one of
the moll common fubftances in moft fprings. Sulphate
of magnefia or Fpfom fait, is not unufual in many mi¬
neral fprings. Sulphate of alumina is rarely found in
mineral waters ; it is more commonly found in the ftate
of triple fait or alum. Sulphate of iron is frequent
in the fprings and lakes of volcanic countries. It has
alfo been found in other places. Sulphate of copper
has only been detefled in the waters which iffue from
copper mines.
Nitrates.—Nitrate of potalh or nitre, is rarely found
in mineral waters. It has, however, been detedled
in feveral fprings in Hungary j fome traces of it have
been obferved in wells in Berlin, and in fome fait
fprings in Germany. Nitrate of lime has been deteft-
ed in fprings in the fandy deferts of Arabia. Nitrate
of magnefia is faid alfo to have been found in mineral
waters.
Muriates.—Muriate of potafh is but rarely found in
mineral waters. It has been detefted in the fprings
of Uleaburg in Sweden. Muriate of foda or common
fait exifts in almoft all waters, as well as in the ocean.
Muriate of ammonia is not very frequent in waters j it
has been detedled, however, in fome mineral lakes in
Italy, and alfo in Siberia. Muriate of barytes is very
rare, but according to Bergman, it has been found in
fome mineral waters. Muriate of lime is very gene¬
rally found in mineral fprings. Muriate of magnefia
is very common in mineral waters. Muriate of alu-
aaina has been detefted in forae mineral waters by Dr
R Y» ^07
Muriate of manganefe was found by Berg- Analyfis 0£
S T
Withering.
man in fome mineral waters in Sweden, and it has late- Mineral
ty been dilcovered, in fmall proportion, in the waters aters’
of Lemington Priors, by Mr Lambe.
Cai Z'Otfctej'.——Carbonate of potafh, it is faid, has been
found in fome mineral waters. Carbonate of foda
exifts very frequently in the waters of many fprings
and lakes. Carbonate of ammonia has been found in
the waters of Rathbone place in London, by Mr Caven-
difti, and in fome waters in France. Carbonate of lime
is commonly found in almoft all waters, and it is held
in folution by an excefs of carbonic acid. Carbonate
of magnefia very frequently exifts in mineral wa¬
ters. When it is fully faturated with carbonic acid,
it is foluble in water, without any excefs of acid. Car¬
bonate of alumina is faid to have been found in the
waters of Avor in Anjou, in France. Carbonate of
iron is frequently found in mineral waters. It is to
this that chabybeate waters owe their diftinguilhin^
properties.
8. Borax, or the fubborate of foda, is found in fome
lakes in Thibet and Perfia.
9. Sulphurated alkali and fidphurated lime, or the HydnuUU
hydro-fulphurets of foda and of lime, have been found phurets.
in mineral waters. It is to thefe fubftances that hepa¬
tic or fulphureous waters owe their diftin&ive proper¬
ties.
. IO‘ Bituminous fubftances have alfb been difeovered Bitumen*
in fome mineral waters. Sometimes they have been
found combined with an alkali. Waters alfo fome-
times contain vegetable and animal matters, but thefe
are not, properly fpeaking, to be confidered as ingre¬
dients in thefe waters.
Sect. III. Of the Analysis of Mineral Waters.
In the analyfis of mineral waters, the firft thing toPh *2C°J
be attended to is. to afeertain the temperature and fi-properties,
tuation of the fprings from which they are obtained.
The fenfible properties are then to be examined, fuch
as colour, tranfparency, fmell and tafte. Of the phyfi-
cal properties of mineral waters, one of the moft im¬
portant and the firft to be afeertained, is the fpecific
gravity. By this means although not with perfeft ac¬
curacy, the quantity of faline ingredients may be
known. But it is only by means of chemical opera¬
tions that the nature of the fubftances with which mi¬
neral waters are impregnated, can be determined; and
by obtaining thefe fubftances in a feparate ftate, or
forming new combinations, that their quantity or pro¬
portions can be accurately afeertained. In the ana¬
lyfis of mineral waters, therefore, after difeovering their
phyfical properties, the objeft of the chemift is firft to
detea the nature of the fubftances, and then the
quantity or proportion of thefe fubftances which they
contain. In both thefe we fhall follow the method
pointed out by Mr Kirwan, in his Effay on the analy¬
fis of mineral waters.
I. Of the Method of Difeovering the Subftances in Mi¬
neral Waters.
I. T he nature of the component parts of mineral
waters is difeovered by the addition of certain fubftances
which produce changes of different kinds. The fub-
4^2 ftaiyes
Tefts.
2209
Gafeous
bodies.
2210
Carbonic
acid.
7o8 C H E M I
Analyfis offtances employed for tin’s purpofe are known in che-
Mineral by the name of tejis or re-agents, becaufe they
._VSravtJr?' 1 ^ uPon t^e fubftances with which the waters are im-
2208 pregnated, by decompohng them, and forming new
combinations.
2. Gafeous fubftances are eafily dete£led, either by
their efcaping in the form of bubbles when the water
is expofed to the air, or, if they are more permanently
held in folution, by boiling a quantity of the water in
a retort, and receiving the gas over water or mercury.
The nature of the gas, thus colledbed, may then be ex¬
amined by the ufual tefts for gafes.
3. Carbonic acid is detected by the infufion of lit¬
mus, not, however, wThen the acid is faturated with any
bafe, unlefs the acid be in excels. Saturated lime
water may alfo be employed as a teft for carbonic
acid. One cubic inch of carbonic acid gas in 7000
grains of water, may be difcovered by this teft. Thefe
effects are not produced by carbonic acid, after the wa¬
ter has been boiled.
4. The infufion of litmus, or paper tinged with it,
is alfo employed as a teft for mineral acids exifting in
waters. A red colour is produced, either when the
acid is uncombined, or united with a bale in excefs.
In this cafe the rednefs is permanent, and is not de¬
ft roved by boiling.
5. Sulphurated hydrogen gas reddens the infu^on of
litmus, and blackens filver or lead, or the folutions of
thefe falts. It is alfo eafily recognized by its peculiar
odour.
6. Carbonated hydrogen gas burijs with common
air wnthout explofion j is not abforbed by lime-water,
drogen gas. ancj ^as no peculiar fmell.
Fixed at ^xec^ alkalies produce a reddifh brown co-
kalies. lQur with the infufion of turmeric. The fame change
takes place with the alkaline and earthy carbonates.
The infufion of Brazil wood affumes a blue colour.
Paper tinged blue with litmus, and reddened wnth vine¬
gar, may be alfo employed as a teft for alkalies ; and
by all the alkaline and earthy carbonates, the original
blue colour is reftored. The muriate of magnefia is
precipitated only by the fixed alkalies. Potafh forms
with nitric acid a prifmatic fait; with acetic acid a
fait which does not deliquefce, and with fulphuric acid,
a fait which efflorefces. Ammonia*, when in confider-
able quantity, is detefled by the fmell. If the pro¬
portion be fmall, it may be difcovered by diftilling
part of the water with a gentle heat.
8. The carbonates of the earths and the metals are
precipitated by expofure to the air, or by boiling and
evaporation. Carbonates of lime, of alumina, and of iron,
are precipitated by boiling for a quarter of an hour. Car¬
bonate of magnefia is only partially precipitated by the
fame procefs.
9. Iron, either in the ftate of carbonate, or combin¬
ed with fome other acid, is dete&ed by tinfture of
galls, which produces a black or purple colour. A
very minute portion of iron is detefted by this teft.
Three grains of cryftallized fulphate of iron dilTolved
in five pints of water, ftrike a purple colour in five
minutes, with a fingle drop of this tinfture. With
this teft the colour affumes different fiiades, according
to the nature of the other fubftances which are in
combination. If the water contains a carbonate of an
alkali or an earthy fait, the colour is violet; it is
221X
Mineral
acids.
2212
Sulphurat¬
ed.
2213
And carbo
nated hy-
4215
Carbonates.
22r6
Iron.
22r?
S T R Y.
dark purple with other alkaline falts j with fulphate Analyfis of
of lime it is firft whitilh, and afterwards black j and
with fulphurated hydrogen gas, the colour is purplilh , ''a < l3‘
red. The latter, Mr Kirwan fufpefls, is occafioned
by manganefe. Iron diffolved in . carbonate of am¬
monia, is at firft whitened, and afterwards blackened
by tin&ure of galls. In the cauftic fixed alkalies the
precipitate is at firft; crimion red, but afterwards be¬
comes black. Pruflian alkali is a fenfible teft of iron j
the precipitate is blue : but if an alkali exifts in the
water, it prevents a fmall portion of iron from ftri^.-
ing a blue colour with this teft, until it be faturated
with an acid.
10. Sulphuric acid is dete£led by muriate, nitrate,Sulphuric
or acetate of barytes j nitrate or acetate of lead , ni-acid.
trate of mercury, nitrate, muriate, or acetate of ftron-
tites, and nitrate, muriate, or acetate of lime. 2218
11. Muriatic acid is readily detefled by nitrate of Muriatic,
filver. It forms a white precipitate, or a cloud in the
water. If there are any carbonates of alkalies or
earths in the water, they mull be previoufly faturated
with nitric acid. Sulphuric acid, or the fulphates, muft
be precipitated by nitrate or acetate of barytes. A-
cetate and fulphate of filver may be alfo employed for
the fame purpofe. 2219
1 2. Boracic acid when it is uncombined, is detefled Eoracic.
by acetate of lead ‘7 but the alkaline and earthy car¬
bonates muft be previoufly faturated with acetic acid.
The fulphates muft be decompofed by means of acetate
of ftrorttites, and the muriates by acetate of filver. 2220
13. Lime is readily detected with oxalic acid j but if Lime,
the water contains any mineral acid, it muft: be pre¬
vioufly faturated with an alkali. Barytes, if any exifts
in the water, muft be precipitated by fulphuric acid.
Magnefia is precipitated very flowly with oxalic acid,
by which it is readily diftinguiflied from lime. 222£
14. Barytes is detefted by diluted fulphuric acid,Barytes,
with which it inftantly forms an infoluble white preci¬
pitate.
15. Magnefia and alumina are both precipitated by
means of pure ammonia and lime water ; but it is necel- aDci aiu_
fary that carbonic acid, if any exifts in the water, bemina.
previoufly feparated by means of a fixed alkali, and by
. boiling. If lime-water is employed, the fulphuric acid
muft be firft precipitated with nitrate of barytes. If
the two earths are precipitated together, the alumina
may be feparated from the magnefia, by boiling them
with pure potafh, which combines with the alumina.
16. Siliceous earth may be difcovered by evaporat-^qq.^
ing a large quantity of water nearly to drynefs, and
then by rediffolving the precipitate in nitric or fulphu¬
ric acid, and afterwards evaporating to drynefs. The
dry mafs redifldlved in water and filtered, leaves the
filica on the filter. 2224
17. Mr Kirwan gives the following diretftions for Sulphates
difeovering the fulphates.
Sulphate of foda is detefted by feparating ammonia
by gentle diftillation, and then by evaporating to one-
half, and afterwards by adding lime-water, while any
precipitate is formed. By this means all the other ful¬
phates are precipitated. By farther evaporation, and
the addition of a few drops of alcohol and oxalic acid,
the whole of the lime is feparated. To the filtered
refiduum add a ftrong folution of nitrate of lime ; and
if the alkaline fulphates exift in the quantity of eight
grains
3225
Sulphate
of lime.
2226
Alum.
2227
2228
Of iron.
2229
Muriate of
C H E M I
Analyfis of grains in TOGO of the liquid, a precipitate will ap¬
pear. To afcertain whether the bale of this alkaline
fait be potafh or foda, add to an equal quantity of the
water acetate of barytes; filter the folution, and eva¬
porate to drynefs. Add alcohol to feparate the other
falts. This folution filtered and evaporated to drynefs
gives an acetate of potalh or foda ; if the former, it de-
liquefces, but if it be the latter, it efflorefces by ex-
pofure to the air.
18. Sulphate of lime is depofited by evaporation to
a few ounces, if it be contained in the proportion of
four grains to 1000. It affords a precipitate with mu¬
riate of barytes, oxalic acid, or alcohol; the latter of
the fpecific gravity of 0.848 produces a cloud inftanta-
neoufiy, in a folution of one grain of the fait in 1000 of
water.
19. The teft for alum is carbonate of lime. With
this, alum forms a precipitate. If the water con¬
tain muriate of barytes, it mull be precipitated with
diluted fulphuric acid. A fulphate of any of the me- „
tals may be precipitated by means of an alkaline pruf-
fiate.
Sulphate of 20. The hydrofulphuret of ftrontites affords a good
magnefia. teq for fulphate of magnefia, and it does not give an im¬
mediate precipitate with any other fait; but the water
fhould be free from any excefs of acid.
21. Sulphate of iron is detefted by expofing it in an
open veffel to the air for a lew days 5 or it may be pre¬
cipitated from the water by means of alcohol.
22. To deteft the muriate of potafh and of foda, it is
potafh and neceffary, firft, to feparate the fulphates, if any exift,
in the mineral water, which is done by means of alco¬
hol and nitrate of barytes. The earthy nitrates and
muriates are decompofed by diluted fulphuric acid, and
the nitric and muriatic acids are expelled by heat.
The falts formed with fulphuric acid may be feparated
by alcohol and barytic water, fo that nothing can now
remain but alkaline nitrates and muriates. The laft is
decompofed by acetate of filver, and if a precipitate is
thus formed, the water contains muriate of foda or of
potafh. To feparate thefe from potafh or foda, eva¬
porate to drynefs, and treat the dry tnafs xvith flrong
alcohol for 24 hours in a temperature of 6o°. The
acetates are thus diffolved and depofited by evaporation.
The acetate of potafh is known by its deliquefcence,
and the acetate of foda efflorefces.
23. Muriate of ammonia is to be detefled by firft
feparating the fulphates by the acetate df barytes, and
then evaporating the folution to drynefs. The mafs
can only confift of acetates and alkaline muriates.
Diffolve the dry mafs in alcohol, and let it remain for
24 hours in the temperature of 6o°. All the falts are
diffolved, except the alkaline muriates.- The refiduum
diftilled with quicklime will give out ammonia, which
will precipitate the folutions of iron, alum or lead,
previoufly introduced into the receiver.
24. Muriate of barytes is difcovered by fulphurio
acid. This is the only barytic fait yet found in mineral
waters.
25. To detefl muriate of lime, firft feparate the
fulphate of lime by evaporation, to a few ounces j add
alcohol, and afterwards nitrate of barytes. Evaporate
the filtered folution to drynefs, treat the mafs with al¬
cohol ; evaporate the folution to drynefs, and re-dif-
iblve the refiduum in water. If a precipitate be
2230
Of ara-
monla.
2231
Of barytes,
2232
Gf lime.
S T R Y. yog
formed, by adding nitrate of filver, oxalic or fulphurip Analyfis of
acid, the folution then may contain muriate of lime ; Mineral
if to a portion of the folution, carbonate of lime be • Ua[ r^ jf
added, alumina is precipitated, if the muriate of alu¬
mina exift in the water, but not muriate or nitrate
of magnefia. Pure ammonia will precipitate mag¬
nefia from its combination with the nitric or mu¬
riatic acid. And if none of thefe earths appear, the
muriatic acid detedled in the water muft be united to
lime.
26. Muriate of magnefia is difcovered by decompo-Of
fing the fulphates by means of nitrate of barytes. Fil- nefia,
ter the folution, evaporate to drynefs, and diffolve the
refiduum in alcohol. Evaporate this folution to dry¬
nefs, and diffolve the refiduum in water. The nitrates
of lime and magnefia, and the muriates of lime, mag¬
nefia and alumina, can only exift in the folution.
Carbonate of lime precipitates alumina; pure ammonia
precipitates magnefia. Muriatic acid is detefted by
nitrate of filver. To afcertain whether the muriatic
acid be united to magnefia, treat another portion of
the folution with fulphuric acid and alcohol. If no
alumina has been found, and no precipitate now ap¬
pears, magnefia is the only earth retained in the folu¬
tion.
27. To deleft the muriates of alumina and iron, of alumina.'
the alkaline carbonates, if they exift in the water, and iron,
fhould be faturated with nitric acid, and the fulphates
decompofed with nitrate of barytes. By adding car¬
bonate of lime to a portion of the water filtered and
purified, the muriates of alumina and iron will be pre¬
cipitated. Muriate of manganefe is alfo feparated by
carbonate of lime. 22„,
28. To difcover the nitrates of potafh and of foda, Nitrate of
precipitate the fulphates with acetate of barytes, and potafh anff’
the muriates with acetate of filver. Evaporate to dryi^a*
nefs, and diffolve the refiduum in alcohol. The alka¬
line nitrates, and a portion of acetate of lime remain
undiffolved. Filter off the undiffolved nitrates, wadi
them with alcohol, and rediffolve them in water.
Carbonate of magnefia decompofes nitrate of lime.
To feparate the nitrate of magnefia thus formed, eva¬
porate to drynefs, add alcohol to the dried mafs ; the
nitrate of magnefia is diffolved, but the alkaline ni¬
trates remain untouched. 22*6*
29. To deleft nitrate of lime, evaporate the water ofliirie.
confiderably to feparate the fulphate of lime which it
may contain, and add alcohol to feparate the other
fulphates. The fulphates being filtered off, and the alco¬
hol expelled by heat, oxalic acid added to the folution,
wall produce a precipitate, if there be any lime in it.
Decompofe the muriates with acetate of filver ; filter
the folution, and evaporate it to drynefs ; diffolve the
dry mafs in alcohol; evaporate this to drynefs, and re¬
diffolve it in water. If nitrate of lime exift in the fo¬
lution, fulphuric acid will difcover it. .
30. To difcover- nitrate of magnefia, the fulphates Of magne-
and muriates are firft to be feparated ; the folution be-fil¬
ing filtered, and evaporated to drynefs, the refiduum
is to be diffolved in alcohol- Evaporate this folution
to drynefs, and diffolve the refiduum in water. Add
to the folution pure potafh, which precipitates the
earthy acetates and the nitrate of magnefia. Filter
the folution, evaporate to drynefs, and treat the refi-
duum with alcohol,, which diffolves the alkaline ace-
tatesJ
7>
CHEMISTRY.
Anajyfis of tates, and leaves the nitrate of potafli untouched ; by
Mineral
Waters.
2238
Bitumen.
2239
2240
Animal.
2241
compa
ble falts.
which procefs it mull: appear, that nitrate of magnefxa
previoully exifted in the water.
31. Alkalies combined with bitumen are fometimes
found in mineral waters. Thefe mineral foaps, or bi-
tuminated alkalies, as they are called by Mr Kirwan,
form a coagulum with the acids. This coagulum is fo-
luble in the alkalies.
32. Extractive matter, which is fometimes found in
matter^'6 m*nera^ vvat-ers? is difcovered by means of nitrate of lilver,
with which it forms a brown precipitate, but the water
containing it mull be freed from fulphuric and muriatic
acids with nitrate of lead. Three grains of the pre¬
cipitate, according to Weltrumb, indicate one grain
of extractive matter.
33. Animal extractive matter gives a very difagree-
able talte and fmell to water. It is foluble in alcohol.
Incom ati T!le fullow5nS is a of falts which are incom-
blefZ PatIb]e wkh each or which cannot exilt together
in the fame water.
1. Alkaline carbonates j and earthy or metallic ful-
phates, muriates, or nitrates.
2. Sulphuric acid 5 and earthy nitrates, muriates, or
carbonates.
3. Alkaline fulphates j and earthy nitrates, or mu¬
riates.
4. Sulphate of foda ; and muriate of potalh.
5. Sulphate of potalh ; and nitrate of foda.
6. Sulphate of ammonia j and nitrate of potalh, and
muriate of potalh.
7. Sulphate of magnelia ; and nitrate or muriate of
lime.
8. Alum j and nitrate of lime and of magnelia, or
muriate of magnefia.
9. Nitrate of lime 3 and muriate of potalh, muriate
of ammonia, of barytes, or magnelia,
10. Nitrate of magnelia 5 and muriate of barytes
and of potalh. -r
11. Muriate of magnefia 3 and nitrate of foda or
lime .
* AnalyJU
of Min.
Wat. p.
34 142-
II. Of the Method of ascertaining the Proportions of
Subftances in Pvlinersl Waters.
,224a 1. In examining any mineral water, it has been al- ’
firft afeer- J.hePhyfical properties, and efpecially thefpecific gravity
tained. lrom which the quantity of faline matter, as Mr Kir’
wan obferves, may be effimated. The method he pro.
pofes ts the following. He fubtrafla 1000, the fpedfic
gravity of pure water, from the fpecific gravity of the
mineral water ,0 be examined, exprelfed in whole num!
bers, and multiplying the produfl by ,.4, which gives
the weight of the falts freed from their water of^erv.
ftalhzation. Thus, a folution of common fait, whofe
fpeefie gravity ,s ,.o79. A thoufand fubtraftri from
this leaves 79, which multiplied by ,.4 is c1ual fo
11 o.S which is the quantity of faline matter in 1000
2243 Parts of the folution of common fait.
Cafeous “'AAf!er Jfo<!«aming the phyftcal properties the
bodies. firft ftep ,n the analyfis is ,0 eftimate {he quantity of
gafeous bodies which the water contains. Thefe are
oxygen gas, azot.c gas, atmofpheric air, fulphurat 'd
hydrogen gas and fulphurous acid. They are re be
colleaed by heating a quantity of the wafer in a re
tort, and receiving the gas over water, or over mer- Analyfis of
cury, if it is abforbed by water. The nature of the Mineral
gas will be afeertained by the different tells which Water5- ,
have been already mentioned for detecting the gafes, ‘'“““V—
and the quantity of it may be afeertained, by calcu¬
lating the bulk, taking care to make the proper allow¬
ance for the difference of preffure of the air and tem¬
perature. But for this fee Mr Kirwan’s method of
calculation, in his Effay on the Analyfis of Min. Wat.
P* I78‘ . 2244
3. To difeover the carbonates which may exift ln Carbonate*
the water, is the next Itep in the analyfis. There may
be carbonate of lime, of magnefia, of alumina, or iron.
If the water contains fulphurated hydrogen, it mull
be feparated by expofure to the air, or by means of
litharge. Filter and boil a quantity of the water for
half an hour. In this way it is deprived of the earthy
or metallic carbonates, if the water contains no ful-
phurated hydrogen. It is to be boiled for a quarter of
an hour, expofed to the air till it is cool, and filtered.
Diffolve the precipitate in diluted muriatic acid. The
whole are foluble in this acid, excepting alumina and
fiilphate of lime. Let the refiduum be expofed to a
red heat ; mark the weight, and boil it in carbonate of
foda. . Saturate the foda with muriatic acid, and boil
the mixture for half an hour. Carbonate of lime and
alumina are thus precipitated. Diffolve the dried pre¬
cipitate in acetic acid- I he lime is diffolved, but the
alumina remains. The weight of the lime, after beina
dried, lubtradled from the original weight, gives the
proportiori of fulphate of lime. To feparate the iron,
add ammonia to the muriatic folution, as long as a red-
ddh precipitate is perceived. If magnefia be precipi¬
tated with the iron, expofe the precipitate in the open
air for fotne time, to a heat of about 2oo°; add acetic
acid in final] quantities, to diffolve the magnefia ; the
iron thus feparated, is to be re-diffolved in muriatic
acid, precipitated by an alkaline carbonate, and gently
dried and weighed. The acetate of magnefia is next
to be precipitated and eftimated as above. The mu¬
riatic folution is thus freed from iron and part of the
magnefia. Add fulphuric acid as long as any preci¬
pitate appears ; heat the folution flightly, and add al¬
cohol. The fulphate of lime is feparated and heated
to rednefs. A hundred grains are 22: 70 of carbonate
of lime. The magnefia is to be precipitated by car¬
bonate of loda, dried and weighed. The whole of the
carbonate of magnefia is not precipitated by boiling.
Evaporate the boiled water nearly to drynefs. The
carbonate of magnefia and fulphate of lime will be de-
pofited. . Add a large quantity of boiling diftilled wa¬
ter, which will diffolve the fulphate of lime, and
other fubftances. The carbonate of magnefia remains
bchmd, and may be collefted, dried, and weighed.
I he carbonate of alumina and fulphate of lime are to
be eftimated by weighing them, after they have been
dried in a red heat. 22^
4. I o afeertain the proportion of fulphuric acid, Sulphuric
add barytic w-ater to faturation, and weigh the preci- acid-
pitate after it has been expofed to a red-heat. A
hundred parts of the fulphate of barytes contain 22
of real fulphuric acid. To determine the quantity'of i\/r
muriatic acid, like wife add barytic water,* till it is Munatic*
neutralized, then precipitate the barytes with fulphu-
nc acid. A hundred parts of barytes take up 31.8 of
real
Waters.
2247
Boracic.
2248
2249
Of lime.
2250
C H E M
Ana'yfis of real muriatic acid. The proportion of boracic acid
Waters^ ma^ ^ a^certa^ne^ ^7 precipitating it with acetate
a *' of lead. The precipitate is to be digefted in a heat
of 200* for an hour with fulphuric acid. Evaporate
the folution to drynefs, and add to the dried mafs 10
or 12 times its weight of alcohol. Diftil and eva¬
porate this folution ; the boracic acid remains behind,
which may be dried and weighed.
Sulphate of 5: Thc alkaline fulphates are precipitated by means
foda. nitrate of barytes. A hundred and feventy parts
of ignited fulphate of barytes indicate 100 of dried ful-
phate of foda; and 136.86 of fulphate of barytes in¬
dicate 100 of dry fulphate of potafh.
6. Sulphate of lime is moft conveniently determined
by evaporating to a few ounces, and adding a few
drops of alcohol, which will precipitate the fulphate
of lime. It is then to be dried and weighed. The
proportion of alum in a mineral water is afcertained by
evaporating to one-half, and precipitating by means of
carbonate of lime. Acetic acid added to the precipi¬
tate, combines with the excefs of lime which may
have been added. The alumina thus freed from the
carbonate of lime, is to be heated to incandefcence
for half an hour. Twelve parts denote 100 cryftal-
lized alum, or nearly 49 of the-dried fait.
- - 7- If no other fulphate exifts in the water, fulphate
^ maguc- op magnefia may be eftimated by precipitating the acid
with barytic fait. A hundred grains of fulphate of
barytes indicate 52.11 of fulphate of magnefia. But
, if the water contains fulphate of lime, without any
other fulphate, it may be decompofed by means of car¬
bonate of magnefia. The lime thus obtained being
weighed, lliews the quantity of fulphate of lime. ■ By
adding barytes, the whole of the fulphuric acid is
precipitated, and thus the quantity of this acid may
be eftimated. Then by fubtrafting the quantity of
fulphuric acid belonging to the fulphate of lime, the
remaining portion indicates what was combined with
the magnefia. If the water is found to contain ful¬
phate of foda, none of the earthy nitrates or muriates
can exift along with it. If, therefore, no other earthy
fulphate has been dete&ed, the magnefia is to be pre¬
cipitated by means of foda, and is then to be dried
and weighed ; 36.68 parts indicate 100 of dried
fulphate of magnefia. If fulphate of lime accompany
thefe two fulphates, the precipitate confifis both of
lime and magnefia. It is then to be diffblved in ful¬
phuric acid and evaporated to drynefs. By adding
twice its weight of cold water, the fulphate of mag¬
nefia is diffolved ; the fulphate of lime is infoluble.
Evaporate the fulphate of magnefia to drynefs, expofe
it to a heat of 400°, and weigh it. If the water con¬
tain alum inftead of fulphate of lime, the fame procefs
may be followed. But the precipitate being dried,
mull firfl be treated with acetic acid to diflolve the
magnefia, but the alumina remains untouched. Sul¬
phate of iron is feparated by expofing the water to the
air for fome days, and then adding alumina. The
iron is precipitated in the ftate of oxide, and the ful¬
phate of alumina, being infoluble, is precipitated at
the fame time. Thefe falls being previoufly feparated,
the proportion of fulphate of magnefia may be ellimat-
ed in the way which has been already defcribed.
Of iron1 proportion of fulphate of iron may be efti¬
mated by the following procefs. Let the weight of a
I S T R Y. 7I,
precipitate formed with prufiiate of potafti in a folu- Analyfis of
tion of a known weight of fulphate of iron in water,
be previoufly afcertained. Then with the fame pruf-
fiate precipitate the fulphate of iron in the water. But
if muriate ef iron has been dete&ed in the water ; eva¬
porate to drynefs, and add to the reftduum alcohol,
in which the muriate, but not the fulphate, is folu-
ble.
9. PTuriate of potafti or of foda, unaccompanied with Muriate of
other falls, may be eftimated by precipitating by means P°^aih and
of nitrate of filver. 217.65 grains of muriate of fil-
ver denote 100 of muriate of potafh; and 235 grains
of muriate of filver denote 100 of muriate of foda.
If the water contains any of the alkaline carbonates,
they mull be previoufly feparated by faturating with
fulphuric acid. The muriatic acid is then to be pre¬
cipitated by fulphate of filver. Muriate of ammonia
is decompofed by means of barytic water ; the ammonia
is expelled by boiling, the barytes is precipitated by
fulphuric acid, and the muriatic acid is fatuiated with
foda. The fulphate of barytes denotes the quantity of
muriate of ammonia. 2253
10. If the common fait be accompanied with muri-Oflime,
ate of lime, of magnefia, of alumina, or of iron, thefe ^:'c‘
may be precipitated with barytic water, and each earth
walhed, but not dried, re-difiblved in muriatic acid. If
only one of thefe falls be found, faturate the excels of
acid with a known quantity of an earth of the fame
kind, and evaporate to drynefs. Then dedu£I from
the weight that of the muriate formed by the earth
added : thus 50 grains of lime denote 100 of muriate of
lime heated to rednefs ; 31 grains of magnefia indi¬
cate 100 of muriate of magnefia; and 21.8 grains
of alumina indicate 100 of muriate of alumina. The
barytes is precipitated by fulphuric acid ; and the
muriatic acid is driven off by heat. The muriate of
foda may then be eftimated by evaporation ; but the
proportion of muriate of foda, which the known quanti¬
ty of muriatic acid feparated from the earths denotes,
muft be deduced.
If fulphates and muriates are found accompanying
each other, the former may be precipitated by alcohol,
or by evaporating the whole to drynefs. The earthy
muriates may then be diffolved in alcohol. Sulphate
of lime, accompanying alkaline and earthy muriates, is
decompofed by muriate of barytes, and the precipi¬
tate of fulphate of barytes indicates the proportion of
fulphate of line.
If muriates of foda, magnefia, and alumina, accom¬
pany the fulphates of lime and magnefia, the water
to be examined is to be divided into two equal por¬
tions. To precipitate the whole of the lime and alu¬
mina, add to the one portion carbonate of magnefia.
The proportion of lime in fulphate of lime is then to
be afcertained ; and, by precipitating the fulphuric
acid by means of muriate of barytes, the quantity con¬
tained in the fulphates of magnefia and of lime is afcer¬
tained. The proportion of fulphate of magnefia is de¬
termined by deducting this laft portion. The whole
of the magnefia and alumina is precipitated from the
fecond portion of water by lime water. The quantity
of thefe earths indicates the proportion of muriate of
magnefia and alumina, deducing that portion of mag¬
nefia which was difcovered in the rtatc of fulphate in
the firft portion of water. The fulphuric acid is then
precipitated
712 C H E M
Vegetables, precipitated by barytic water, and the lime by car-
' bonic acid } the common fait is obtained by evapo-
Nitrate^of rat‘nS t^le water to drynefs.
potafli. ° 11< Nitre may exift in water with all fulphates and
-muriates which are not incompatible with each other.
After fufficient evaporation, the fulphates are to be
precipitated by acetate of barytes, and the muriates by
acetate of filver. Filter and evaporate to dryoefs j and
add to the refiduum alcohol, which diffolves the ace¬
tates. The nitrate ot potaih, which remains undifibl-
ved, may then be eflimated. If foda be found in the
water, it muft be previoufly faturate<l with fulphuric
acid. -
If nitre be accompanied with common fait, nitrate
cf lime, muriate of lime, muriate of magnefia, evapo¬
rate to drynefs, and add alcohol, which diflblves the
earthy falts. Re-dilTolve the dry refiduum in water,
from which the nitre and common fait may be fepa-
rated by acetate of filver. Evaporate the fpirituous fo-
lution to drynefs, and re-diffolve the refiduum in wa¬
ter. The weight of muriate of magnefia is afcertained
by precipitating by means of nitrate of filver. The
weight of the nitrate of lime is determined by precipi¬
tating by means of fulphuric acid: 35 grains denote 100
* See slnal. oi dry nitrate of lime. *
M.in. Ura-
T/iI7S~ Chap. XVII. Op MINERALS.
In following out the arrangement which we have
laid down at the beginning of this treatife, we ftiould
now enter upon the confideration of mineral fubftances.
To preferve the chemical inveftigation of the different
departments of nature unbroken, we propofed to em¬
ploy this chapter in a general view of the chara&ers
of mineral bodies, of their compofition and methods
o, analyfis ; but as this article has been Unavoidably
extended to fo great a length, we fball referve the
whole to the article Mineralogy, where they will be
fully detailed.
Chap. XVIII. Of VEGETABLES.
Divifion of L Natural bodies may be properly divided into 01
natural bo- gamzed and inorganized, each of which exhibit ch?
dies. rafters lufficiently difcriminative. The fubftances ir
cluded under the 17.preceding chapters, belong to tb
atter clafs. Organized fubftances are vegetables an
animals, which are to be treated of in this and th
following chapters. The diftinftion between thefe tw
claues of bodies, although in fome cafes it is lefs ob
vious in general is eafily recognized. The moft per
tect forms of inorganized matter afford no marks c
relembiance to the varied and complicated ftrufture c
a p.ant or an animal. In the mode of formation, o
gl;0J-h a£d “‘creafe of the individuals of thef
two claffes,_ there is the moft ftriking diverfity, whic
exhibits plain and certain charafters of diftinftion. I,
one clafs the growth or increafe takes place bv th
mere aggregation of the particles of matter already pre
pared, and according to. the laws of affinity between^
the particles; and no new properties exift in Se Z
gtegate, which did not exift m the minuteft particle o
which it is compofed. The other clafs of bodie tm
prehending vegetables and animals, exhibits a ver’y di
,crent procefs. 1 he fubftances whigh enter into the
I S T R Y.
compofition are received into tubes or veffels, afe con-Vegetables,
veyed by them to every individual part of the vege- v~--'
table or animal, are fubjefted to peculiar changes, and
affume new forms, poffeffing properties and qualities
which could not be previoufly detefted in the fimple
elements, by any chemical or mechanical operation.
This is indeed the effential charafteriftic of vegetables
and animals. The particles which compofe a cryftal,
formed by the evaporation of water, were held in folu-
tion by the water, and invariably and uniformly ar¬
ranged according to certain laws; but the almolt in¬
finite variety of fubftances which compofe vegetables
and animals, are not to be found in the materials
which are neceffary to promote their growth and
health 5 neither in the water, the earth, the air, the
heat nor the light, all which contribute their fhare to
the fame end. Thefe undergo new changes, and en¬
ter into new combinations, none of which exifted in
the fimple elements, and none of which can be effeft-
ed by any mechanical or chemical procefs. Indeed
the laws which regulate vegetable and animal opera¬
tions, feem to be totally different from the eftablifhed
laws of chemical aftion. Hence from obferving this
difference of aftion, the exiftence and influence of a
different principle have been inferred in animals and ve¬
getables. This has been called the •vita/principle, or
the principle of life, becaufe by its influence the varied
and complicated phenomena of animals and vegetables
are exhibited, which cannot be accounted for on me¬
chanical or chemical principles. It is by the influence
of this principle that the animal or vegetable feems to
poffefs the refnarkable power of refilling or counteraft-
ing to a certain degree the effefts of chemical or mecha¬
nical agents which may prove injurious to its exiftence ;
the power of regulating and feltfting what is beneficial
and neceffary, of fupplying what is deficient, and of cur¬
tailing what is redundant. Organized fubftances admit
of a natural divifion into vegetables and animals. The
bodies included under each of thefe divifions have fome
points of refemblance •, but in general are fufficiently
charafterized and diftinguifhed from each other, by
their form, ftrufture, power of motion, component
parts -and peculiarities of habits. The firft of tbefe
divifions, namely vegetables, forms the fubjeft of the
prefent chapter.
2. A vegetable is compofed of a root, Item, leaves, Strufture
flowers, fruits, and feeds j and when all tbefe different of plants:
parts are fully developed, the vegetable is faid to be
perfeB. When any are deficient, or at leaft lefs obvi¬
ous, the vegetable is faid to be imperfett. 2257;
1 he root is that part of the plant which is concealed Root,
in the earth, and which ferves to convey nourifhment
to the whole plant. I he Item, which commences at
the termination of the root, fupports all the other parts
of the plant. When the ftem is large and folid, as in
trees, it is denominated the trunk, which is divided
into the wood and the bark. The bark conftitutes 225?
the outermoft part of the tree, and covers the whole of
the plant from the extremity of the roots to the ter¬
mination of the branches. The bark is compofed of
three parts, namely the epidermis, the parenchyma,
and cortical layers. The epidermisr which is a thin
tranfparent membrane, forming the external covering of
the bark, is compofed of fibres croffing each other.
When the epidermis is removed, it is reproduced!
The
2259
Wood.
iz6o
Pith.
2261
Flowers
and fruits.
C H E M
Vcjreubles. The parenchyma, which is immediately below the
' epidermis, is of a dark-green colour, compofed of fibres
eroding each other in all direftions, and is fucculent
and tender. The cortical layers which conftitute the
interior part of the bark, are compofed of thin mem¬
branes, and increafe in number with the age of the
plant.
The wood immediately under the bark, is compofed
of concentric layers, which increafe with the age of
the plant, and may be feparated into thinner layers
which are compofed of longitudinal fibres. The wood
next the bark, which is fofter and whiter, is called the
alburnum. The interior part of the trunk is browner
and harder, and is denominated the perfect wood.
In the middle of the ftem is the pith, which is a
foft, fpongy fubftance, compofed of cells or utriculi
as they are called. In old wood this part entirely
difappears, and its place is occupied by the perfeft
wood. The leaves are compofed of fibres arranged in
the form of net-wOrk, which proceed from the Item,
and footftalks by which they are attached to the
branches. Ihefe fibres form two layers in each leaf,
which are deltined to perform different functions. The
leaves are covered with the epidermis, which is com¬
mon to the whole of the plant. Each furface of a
leaf has a great number of pores and glands, which
abforb or emit elaltic fluids. Flowers are compofed of
different parts. The calyx or cup is formed by the
extenfion of the epidermis ; the corolla is a continua¬
tion of the bark, and the ftamina and piftilla, the in¬
ternal parts of frudfification, are compofed of the
wmody fibres and pith of the plant. Fruits are ufually
compofed of a pulpy, parenchymatous fubftance, con¬
taining a great number of utriculi ox veficles,and traverf-
ed by numerous veflels. Seeds are conflituted of the
fame utricular texture, in the veficles of which is de-
pofited a pulverulent or mucous fubftance. Thefe cells
have a communication with the plant by means of vef¬
lels, and by thefe is conveyed the necelTary nourifh-
ment during germination.
Plants contain different orders of veffels, which are
diftinguifhed from each other by their courfe, fituation,
and ufes. Lymphatic veffels ferve for the circulation
of the fap. They are chiefly fituated in the woody
part of the plant. The peculiar veffels, which general¬
ly contain thick or coloured fluids, are placed im¬
mediately under the bark ; they are fmaller in num¬
ber than the lap veffels, and have their interftices filled
up with utriculi or cells, with which they form a
communication. Some of thefe proper veffels are fituat¬
ed between the epidermis and the bark, which are
Readily detected in the fpring. Some are fituated in
the interior part of the bark, forming oval rings, and
filled with the peculiar juices of the plant. Another
fet of proper veffels is placed in the alburnum, nearer
the center of the flock or trunk, and fometimes in the
perfedft wood. The utriculi or cells conftitute another
fet of veflels, which feem to refemble a flexible tube,
ilightly interrupted with ligatures at nearly equal dif-
tances, but ftill preferving a free communication through
its wEole length. They vary in form, colour, and
magnitude in different vegetables, and exift in the
roots, the bark, leaves, and flowTers. The tracheae
or fpiral veffels, which are readily detefted in fucculent
plants, appear in the form of fine threads, and may be
Vol. V. Part II.
'•2262
%Teirels.
I S T R Y. 7,3
drawm out to a confiderable length without breaking. Fun&ions
Thefe veffels are very numerous m all plants, efpecially of Vegeta-
under the bark, where they form a kind of ring, and ^es‘ ,
are diipofed in diftinft bundles, in trees, flifubs, and
ftalks of herbaceous plants.
After thefe preliminary obfervations on the charac¬
ters of organized fubftances, and the general ftru&ure
of plants, we now' proceed to give a fhort view of the
fundions, decompofition, and component parts of ve¬
getables. Thefe fhall form the iubjed of the three
following fedions.
Sect. I. OJ the Functions of Vegetables.
I. Of Germination.
1. When the perfed feeds of a vegetable are placed 225,
in certain circumflances, they produce plants exadly Tempera-
fimilar to thofe from w'hich they originated. The re-ture.
quifite circumftances for the germination of feeds are,
heat, air, and moifture. It is well known that no vege¬
tation goes on when the temperature of the air is at
the freezing point, and very little till it rifes a con-
fiderable number of degrees above it. The feeds of
different plants, it is obferved, require different degrees
of heat for their germination, and hence, the various
feafons and climates in wdiich different plants and feeds
are found to vegetate.
But whatever the temperature may be, no feeds ger- .
ruinate, unlefs they are expofed to the adion of the^
air. It is found that it is the oxygen of the air which
is neceffary for the produdion of this change j for when
it is entirely excluded, no change takes place, and
when it is in greater quantity, vegetation is more ra¬
pid and more vigorous.
Moifture is alio neceffary for the vegetation of feeds..»
But although water be neceffary for this purpofe, jt 01lUie"
muft be applied in moderate quantity, for, except the
feeds of aquatic plants, wdiich are poffeffed of peculiar
habits, moft feeds are deprived of their vegetative
power, and entirely decompofed, when they are kept in
water. Hence it is that many feeds do not vegetate in
ftiff clay foils, which retain too much water, nor in
Tandy foils, which allow the whole of the water to
filter through them. Many feeds, although they arr
expofed to the favourable adion of thefe agents, do not
vegetate when they are expofed to the adion of light.
It is on this account, and alfo no doubt, for the proper
application of moifture, that feeds are covered with the
foil, by which means germination is found to be great¬
ly promoted. ^
4. A feed is compofed of three principal parts, which Parts of
have been denominated the cotyledons or lobes, the ra-,eeds>
dicle, and plumula. The greateft number of feeds
have two cotyledons. Some, however, as many of the
farinaceous feeds, and feeds of graffes, have only one.
Other feeds have three, and fome fix. Hence plants
have been diftinguiftied into mono-cotyledinous, di coty-
ledmous, and poly-cotyledmous.
5. The firft change which takes place on a feed Root fonn-.
placed in circumftances favourable for germination, isecb
the incrcafe of fize by the abforption of moifture. The
radicle is then formed, which ftretches downwards in¬
to the earth. The plumula (hoots upwards, and ex¬
pands into leaves and branches. The peculiar func¬
tion of the root is to convey nourifhment from the earth
4 X fox
7‘4
Fundlions
of Vegeta
bles.
2268
Oxygen ab
forbed.
22(?9
Carbonic
acid gas
emitted.
C H E M
for the future growth of the plant $ but from what
fource is the nouriihment derived for the formation of
_ the root itfelf ?
6. The very firft change which takes place within the
-feed is the combination of the oxygen of the air which
is abforbed, with the carbone which exifts in the lobes
of the feed, and the formation of carbonic acid, which
is given out in the ftate of gas. The farinaceous mat¬
ter of the feed being deprived of part of its carbone, is
converted into a faccharine fubfcance, which is deftin-
ed for the nourifliment of the embryo plant, till its
parts are fo far evolved, and its ftrudlure fo completed,
as to derive nourifhment from the earth.
7. The firft chemical change, therefore, which is
obferved in the germination of feeds, is the abforption
of oxygen, the emiffion of carbonic acid gas, and the
converfion of the farinaceous matter into a faccharine
fubftance. This is the procefs of germination, as it
has been deferibed by chemical phyfiologifts. But if
oxygen gas be entirely excluded, no change takes
place ; no part of the procefs of germination goes on ;
or even if it has proceeded fo far as that the plumula
fhall have appeared above the furface in the form of
feminal leaves ; if thefe leaves are removed before
others have been unfolded, the plant dies. The fe¬
minal leaves are the lobes which have been pulhed out
of the earth along with the plumula, fo that if they are
defiroyed, the plant is cut off from the neceffary fource
of nourifhment for the evolution of its parts, and the
formation of roots and leaves, which are deftined to
perform the different fun&ions of vegetation.
II. Of the Food of Plants.
2270
Suppofed to I. But air, heat, and moifture, are not only neceffary
be water. for the formation of the different parts of the plant j their
aftion muft be continued, and are abfolutely requifite
for its future health and growth. It could not long
efcape obfervation, that plants ceafe to vegetate when
they are entirely deprived of water. Hence it became
the opinion of the earlier phyfiologifts, that water con-
ftituted the chief, or the only food of plants j but it
has been proved by experiments in analyzing plants
which grew in pure water, that they received no in-
creafe of one of the neceffary principles in their confti-
tution, farther than what previoufly exifted in the feeds
or roots from which they fpring. In a feries of ex¬
periments inftituted by Haffenfratz, on the roots of
hyacinths, the feeds of kidney beans and other feeds,
he found that the quantity of carbonaceous matter in
the full-formed plant, was even lefs than what previ¬
oufly exifted in the bulb or feed.
- - z- But although pure water feems not to contribute
vent of the to the growth of plants, yet it is neceffary as a f'olvent
food. for thole fubftances which are confidered as the proper
food ot vegetables. But when water is impregnated
with certain fahne and earthy, but efpecially with
carbonaceous matter, it is then found to be moft pro
per for promoting the growth and increafe of vege-
tables. We have obferved plants growing in a foil
which was frequently moiftened with the water from a
dung-hill, advance with a more rapid and vigorous
growth and attain to a larger fize, than fimilar plants
in the lame foil, which received only the ufual fupplv
of rain and dew from the clouds. It has been found
by experiment, that this water holds in folution a con
2271
Kot pure.
2272
3s the fol-
I S T R y.
fiderable portion of carbone. It is not improbable Functions
that it alfo contains fome of thofe faline matters which of Vegeta-
have been dete&ed by analyfis in plants in the greateft bles‘ ,
health and luxuriance. The watte of the foil muft v
be repaired with frequent additions of manure, which
may be conftdered as neceffary fupplies of food or
nourifhment.
3. But whatever may be the food of plants, it is taken PeculiX
up by the roots in the ftate of folution in water, and ftnidture of
conveyed by the veffels to every part of the vege-the root*
table. For this purpofe it would appear that there
is a peculiarity of ftru&ure in the extremities of the
roots ; for, if part of the fibre of a root be cut off,
the plant ceafes to vegetate till new fibres are formed,
which are fo conftrudted, as to be capable of abforbing
the neceffary quantity of water.
4. This fluid, which is found in plants, is called the Sap!27**
It is moft abundant in the fpring, as the feafon
of vegetation advances; and during that feafon, when
the plant is wounded, it flows out copioufty, and it is
then laid lo bleed. This is particularly the cafe with
fome trees, fuch as the birch and a fpecies of maple >
the lap of which, by certain procelies, yields wine or fu-
gar. The fap is contained in what is called the lym¬
phatic or common veffels of the plant. 2 7-
5. The fluids taken up by vegetables, it is probable, Is prepared
no fooner enter the plant, than they undergo fomeinthe
change. Vauquelin has dire&ed his attention to thisplant’
fubjea, and has analyzed the fap at different periods 2275
during the feafon of vegetation. The fap of the com- Sap of the
mon elm (til mu.1 campejlris Lin.) extracted from the elm.
tree early in the fpring, was of a brown colour, had
a fweet, mucilaginous tafte, but fcarcely reddened the
tinfture of turnfole. Ammonia produced in this fluid
a copious yellow precipitate, foluble with effervefcence
in acid. Barytes and lime-water produced a fimilar
effeff. Oxalic acid and nitrate of filver gave a white
precipitate. Sulphuric acid, diluted with water, occa-
fioned a brilk effervefcence, with the evolution of the
odour of acetic acid from the mixture. Oxymuriatic
acid deftroyed the colour of the fap, and formed in the 2277
liquid a yellow precipitate. Hydrofulphuret of pot-Expen-
afh and fulphate of iron effe&ed no change, but alco-ments-
hoi threw down a flaky precipitate. A quantity of
this fap being evaporated with a moderate heat, there
was found on the furface a brownifh pellicle ; a brown
matter feparated in the form of flakes, and an earthy
matter depofited on the fides of the veffel, which was
dry to the touch. After evaporation to a certain de¬
gree, and cooling, a yellow earth was depofited, which
difiolved with effervefcence in muriatic acid. When
the folution was completed, the liquid was filtered, to
feparate the infoluble vegetable matters. The muria¬
tic folution mixed with carbonate of potafli, yielded
carbonate of lime. 1 he liquid which had depofited
the vegetable matter being evaporated with a gentle
heat afforded a grayifti extra&, which ftrongly attra&ed
moifture from the air, and had a very pungent, faline
tafte. .It effervefeed with the addition of concentrated
fulphuric acid, and gave out the odour of radical vine¬
gar. Diftilled with three parts of fulphuric acid, it
furnifhed very concentrated acetic acid, and there re¬
mained in the retort fulphate of potafti with excefs of
acid.
6. From this analyfis it follows, that the extra# of the
fap
C H E M
Fundlions fap of the elm is chiefly compofed of acetate of potafli.
^ne t^ou^in^ an^ thirty nine parts of this fap yielded
. l^' nearly the following proportions.
2278
Compofi.
tioa.
Acetate of potafh 9.240
Vegetable matter 1.060
Carbonate of lime .796
The deficiency was made up of water and fome vola¬
tile matter.
When the feafon was farther advanced, the fap of
the fame tree w'as again fubjefted to analyfis, and it
was found that the quantity of acetate of potafli and
carbonate of lime had diminifhed, but that the quan¬
tity of vegetable matter was nearly double. At a
ftill more advanced period of the feafon, the experi¬
ment was repeated, the refult of which was, that the
increafe of the vegetable matter, and the diminution
of the acetate of potafli and carbonate of lime were
flill greater. It appeared too, that carbonic acid ex-
ifted in excefs in the fap, and that the carbonate of
lime was held in folution by it.
Of the 7- f'he fame chemifl analyzed the fap of the beech,
'beech. and it was found to be compofed of water, acetate of
lime with excefs of acid, acetate of potafli, gallic
acid, tan, mucus, extra&ive matter, and acetate of
alumina j but the proportions of thefe parts have not
been mentioned. From this analyfis it appears, that
the fap of the beech is different from that of elm, in
containing acetic acid uncombined, befides gallic acid
^nd tan, but at the fame time having no carbonate of
lime. When the fap of the fame plant was examined
d?i latter in the feafon, the proportion of gallic acid and
20’m”\ ' tan had increafed. Vanquelin alfo examined by ana*-
2280 tyfo* the fap of the carpinus fylveftris or hornbeam, and
Of the the betula alba or birch *. The component parts of
hornbeam, the fap of the former were found to be, acetate of po¬
tafli and lime, mucilage, fugar, and extraft, with
water j and the latter were found to be water, acetates
of lime, alumina and potafli, fugar, and vegetable ex-
traff. From thefe experiments it appears that the
fluids which are taken up by plants, are immediately
changed by certain proceffes wuthin the plant *, for
fome of the fubftances which are component parts of
the fap of plants, are either not found in the liquids
before they enter the plant, or exift in them in very
fmall quantity. Thefe changes, it appears too, from
the fame experiments, are confiderably greater, at the
later periods of the feafon of vegetation. Some of the
component parts are greatly increafed, while others
are much diminiflied.
Afcends The fop afcends from the roots to the extremities
through the of the branches, which has been proved by making
wood. incifions in the trunk of a tree at different heights in
the fpring feafon. The fap is obferved to flow, firft,
from the loweft incifion, and fucceflively to the high-
eft. It is through the veffels in the woody part of
the tree, that the fap afcends, for no fap flows from an
incifion unlefs it has penetrated the wood, and in fome
trees it is neceffary to make the incifion nearly to the
center. It has been obferved that coloured infufions
always pafs from that part of the wood called the al-
2282 burnum.
By the 9* The fap of plants is conveyed through thofe vef-
fracheae. fels which were defcribed under the name of trachea; or
fpiral veffels, Thefe were denominated tracheae or air
I S T R Y. ~ 715
veffels by the earlier phyfiologifts, becaufe being found Fun&ions
empty,-when they were cut acrofs and examined, they0^ ^ cgeta-
were fuppofed to convey nothing but air. ■ .
9. As the fap of vegetables moves with very con- 228^
fiderable force, it has given rife to much fpeculation Caufe of
about the nature of that power, or the caufe by which the afcent,
this is effefled. Malpighi afcribed the afcenfion of
the fap to the dilatation and contraction of the air in the
air-veffels ; while Grew fuppofed that it was owing to
the lightnefs of the vapour, in which ftate he conceived
the fap entered the plant, and was conveyed through
it. By many others the afcent of the fap in vegetables
has been afcribed to the force of capillary attraction ;
but the nature of this aftion, as it is demonftrated and
explained by mechanical philofophers, feems to be in ¬
compatible with the phenomena of the circulation of
the fap in vegetables, and has therefore been rejected
as a hypothefis equally unfatisfaftory with thofe which
have been juft mentioned. It has been afcribed with
more probability to the aftion of the veffels themfelves.
This is owing, in the language of ph\fiologifts, to the
irritability of the veffels, or a certain power by which
they are enabled to contrad, by the aflion or influence
of certain fubftances. This is fuppoled to be the cafe
with the fap, and the aClion which takes place when it
enters the roots, is owing to the irritability of the vef¬
fels. As the fap is carried a certain length by the firft
contraction, it is carried ftill farther by the fecond; and
thus by fucceflive contractions it is propelled through
every part of the plant, while at the fame time new ad¬
ditions continue to enter the extremities of the root.
III. Of the Functions of the Leaves.
1. Whatever be the nature of the procefs, the fap is
carried to every part of the vegetable, and we have
feen that it has no fooner entered it than it undergoes
certain changes, which become more confiderable ac- 22S(
cording to the length of time after its abforption. But Produce
the greateft changes which take place in the fap of great
plants, are effefted in the leaves. The leaves are to c^a"geson
be confidered among the effential organs of vegetables, e2‘lg^
for in them the fap is totally changed, and converted Convert it
into the peculiar juice, or fuccus proprius of the plant, into the
As the functions of the leaves are of great importance I,ecui‘ar
in vegetation, it will be neceffary to confider the na-Julce‘
ture of their aCtion.
2. During the day, the leaves of plants tranfpire a During the
very confiderable quantity of moifture, the proportion d®)'*
of which, it appears from fome experiments, was not
much inferior to the quantity abtbrbed. From fimi-
lar experiments it appears that the quantity evaporated
was in proportion to the extent of furface of the leaves.
The quantity has been obferved to be greateft too,
during funfhine and warm weather. It is greatly in¬
terrupted during the night, and entirely checked by
cold. When the quantity of moifture tranfpired is di-
miniftied, the moifture imbibed is alfo found to be
lefs in proportion. This indeed might have been ex-
pefted, for when the tranfpiration of a plant ceafes,
this being an effential funftion of vegetation, the whole
procefs muft be interrupted. In experiments made on
this tranfpired matter, by evaporating to drynefs a
quantity which had been colleCled, a fmall portion
of carbonate of lime was obtained j from the refiduum,
4X2 a
i6
C H E M
2288
Carbonic
’acid gas ab
forbed.
228p
Adlion of
light.
7
Functions a fmaller proportion of fulphate of lime, with a
01 bleT^' Summy anc^ refinous matter. It has been found
> y—. . that the tranfpiration of moillure takes place chiefly on
the upper furfaces of the leaves, and this feems to be
2287 performed by a particular fet of organs.
Oxygen gas 3. During the day, and efpecially during bright fun-
given out. fhine, oxygen gas is given out by the leaves of plants..
The quantity of oxygen gas emitted by leaves, as ap¬
pears from the experiments of naturalifts, depends on
the quantity of carbonic acid gas which is abforbed by
the plant; for it has been afcertained that vegetables
grow rapidly and vigoroufly when they are expofed to
this gas ; nay, it is found efientially neceflary to their
health and growth. If the water with which plants
are fupplied be deprived of the whole of its air by
boiling, no oxygen gas is emitted, and water which is
impregnated with the greateft proportion of carbonic
acid gas, gives out the greateft quantity of oxygen
gas.
4. This procefs goes on only during the day, and it
is more vigorous during bright funfhine ; from which
it is natural to conclude, that light performs fome ne-
ceffary part in it. It is well known that plants wrhich
grow in the dark do not acquire a green colour ; and
it is found that thefe plants contain a finaller propor¬
tion of carbone than limilar plants, in the fame cir-
cumftances, expofed to the light. From this it may
appear w-hat is the nature of the procefs when carbonic
acid gas is abforbed by plants, and oxygen gas emit¬
ted. It is the decompofition of the former, which is
effefted ; the carbone being retained in the plant, and
the oxygen given out ; but light being a neceflary
agent in this decompofition, the procefs muft be inter¬
rupted when it is excluded.
5. This decompofition takes place in the parenchy¬
matous fubftance of the leaf, and the quantity emitted,
out the ox- 11 aPPearsy is in proportion to the thicknefs of this fub-
ygen gas. ^ance. The green colour of plants, it has already
been mentioned, depends on the action of light* Plants
which vegetate in the dark, have not only a fmaller
proportion of carbone, but alio continue of a white
colour ; but in a fhort time after they are expofed to
the light, the green colour is reftored.
6. Thus it appears, that it is one part of the func¬
tions of leaves of plants to exhale a confiderable pro¬
portion of the moifture taken in by the roots j to ab-
forb carbonic acid gas 5 to decompofe this gas, by
2291 which its carbone is retained in the plant, and the
Vegetables oxygen is given out. Thus too, it appears, that ve-
fom-So? g£'tableS are .one .of the Sreat fources of fupply of oxv-
oxygen. gen gas’ wb’cb ’s eflentially neceffary in the numer¬
ous procefles of combuftio-n, and the refpiration of ani¬
mals, which are conftantly going on on the furface of
toe earth ; and thus the wafte of this vital fluid is re¬
paired, and the balance preferved between its deftruc-
2292 tlon and foppiy.
Function of 7- The leaves of plants perform a very diffe’-ent func
leaves du- tion during the night. Inftead of emitting moifture
St ^ ,0Xypn S’ and abforbi"g carbonic acid gas,
which takes place during the day, the procefs is re-
verfed. Carbonic acid gas is emitted, and moifture
and oxygen gas are abforbed. The abforption of moi-
f ure feems to be chiefly performed by the under fur-
face of the leaves, at leaf! in many plants. It has be~en
found by experiment, that plants, which have been made
2290
Parenchy¬
ma of the
-leaf gives
I S T R Y.
to grow in oxygen gas give out a greater quantity of Functions
carbonic acid gas, than when they grow in commo-n air. ^e£eta*’
From this circumftance it has been fuppofed, that the , .
carbonic acid gas, emitted by plants during the night,
is owing to the combination of the oxygen abforbed,
w ith the carbone of the fap ; for it is at the fame time
that oxygen is abforbed. It has alfo been afcribed to
the decompofition of the water. x
8. By thefe different procefles which are carried on
in the leaves of plants, by the abftraftion of fome of its
principles, and by entering into minute combinations 2293
with others, the fap undergoes very great changes. It Peculiar
is there converted into the peculiar juice of the plant, ju^ce‘
from which are derived, by other proceffes, the differ¬
ent lubftances which are produced in the different
parts of plants, the nature of which will be afterwards
examined. The leaves of plants have been compared
to the lungs and ftomach of animals. Flow far this
analogy is juft, it is not neceffary to inquire ; but there
can be no doubt that the leaves are effential organs in
the economy of vegetables. In the very firft ftep in
the procefs of vegetation, -during the germination of
leeds, the moifture abforbed by the roots is carried to
the feminal leaves, and there undergoes certain changes,
befofe it is fit for the formation of the ftem and other
leaves of the plant ; for, if thefe leaves are removed,
vegetation is entirely interrupted, and the plant dies.
Fven when plants have made farther progrefs, and are
in full vigour, if they are entirely ftripped of their
leaves, the powers of vegetation ceafe, till thefe necef¬
fary organs are reftored, and new leaves are formed.
The progrefs of vegetation is alfo ftopped when the
furface of leaves is varnixhed over, fo that the ab¬
forption and emiffion of the neceffary fluids are inter¬
rupted.
9. The fap of plants, it has been already obferved,Sap2flo\ts
flows from the root^ towards the branches and leavestrom the
ot the plant. In the leaves it undergoes peculiar !"00ts t0
changes, in confequence of part being exhaled, and ;n ea%es‘
confequence of the abforption of different principles
which combine with it, and no doubt contribute by
this combination to the changes which take place.
The fap, as we have already faid, is then converted in¬
to the Ji/ca/s firoprius, or peculiar juice. It is the fap
of the plant, which is fo far prepared to be converted
into the different parts of the plant, correfponding to
its nature and properties; and, as the different parts,
both of liquids and folids in plants, poflefs properties
totally diftindl from each other, and have derived thefe
from the fame nourifhment, the proceffes by which
thefe different fubftances are produced in different
plants, and even in the fame plant, muft undoubtedly
be different.
10. I he peculiar juice of plants flows from the leaves Peculiar
towards the roots. If a ligature is faftened round thejuice from
ftem of a plant, the place immediately above the liga. ^eaves
ture, that is, between it and the leaves, fwells out [^y tothe roots,
the accumulation of this juice. Or if a wound be
made in the bark, the peculiar juice flows in greater
abilndance from that fide of the wound next to the
leaves, than from the other fide.
11. The peculiar juice of plants has a greater con- pr0pe»1es
fiftence than the other juices. It is readily recognized of it.
by fome peculiarity of colour. In a great many plants
it is milky, in fome it is of a green colour, and in
others
C H E M
Decompofi-others it is red. The component parts of the peculiar
tjon of Ve-juice 0f plants are little known, but from fome ex*
i fiet^)les- _ periments which have been made on this fubjedf, it ap¬
pears that fome part of the vegetable is ready formed.
In the experiments of Chaptal on the peculiar juice
of plants, he deteded a fubftance which poffelfed the
properties of the woody fibre. In limilar experiments
on the feeds of plants, it w^as found that they contain¬
ed a greater proportion of the woody fibre, from which
it is inferred, that the peculiar juices of plants contain
their nourithment ready prepared, and in that Hate in
which it is found in the feed. The peculiar juices of
plants contain a greater proportion of thefe elements
which conftitute the different parts of plants, than what
is found to exilf in the fap. Thefe are carbone, hy-
' 2297 dr°gen> and oxygen.
Plants have 1 2. Many plants ceafe to vegetate as foon as they
different have perfeded their feeds, which is accomplifhed by
periods of f0me in one feafon, by others in two, and hence fuch
urat.on. plants have been called annuals and biennials. Other
plants, however, continue to yield feeds and fruit for
many iuccedive feafons, and to live for a great length
Of time. What is the caufe of this remarkable diver-
fity among the vegetable tribes,—why the humble an¬
nual fprings up, flowers, and forms perfed feeds with¬
in the fhort period of a few months, while the ffately
oak rears its lofty head, and continues to be the pride
and glory of the foreft for hundreds of years, it wmuld
be difficult to fay. At prefent, however, it is not our
proyince to enter into the fpeculation.
Sect. II. Of the Decomposition of Vegetables.
2298
Fermenta¬
tion.
I. As foon as plants have ceafed to vegetate, they un¬
dergo a new fet of changes. The whole plant is broken
down ; the elements of which it is compofed enter in¬
to new combinations, and new fubfiances make their
appearance, wdfich did not previoully exift in the plant.
This decompofition is owing, partly to the affinities
between the component parts of the vegetable them-
felves, and partly to the affinities which exift betw’een
fome of the elementary principles of the plant, and the
heat, air, and moifture, without which no decompofi¬
tion takes plage. While the plant continued to exhi¬
bit the phenomena of vegetation, that is, while it con¬
tinued to live, it poffeffed a powder of refifting this che¬
mical adion between the elements of which it is com¬
pofed, and alfo to a certain extent the adion of external
agents. During this decompofition of vegetables, air,
heat, and moifture, are neceffary. Gafeous bodies are
generally given out, and new compounds are formed.
Some plants, and fome parts of the fame plant, have a
greater tendency to undergo this decompofition than
others, becaufe they either poflefs a greater proportion
of the fubftances which promote the decompofition,
or a greater proportion of the fubftances of which the
new compounds are formed.
2. The changes or fpontaneous decompofitions of
vegetables, as they are almoft always accompanied with
an inteftine motion, have received the name offermen-
tation. The nature of thefe changes is very different,
both with regard to the gafeous bodies which are ab-
forbed or emitted, and the nature of the produds which
are obtained after the procefs is finifhed. Hence, fer-
1 s T R Y.
717
mentations have been ufually diftinguiftied into three'Dccompofu
kinds; namely the fo called, becaufe the pro-tI0ri °! Iv,;-
dud is wine, u'hen certain fubftances are fubjeded to f ^.
this procefs, or beer, when other fubftances are employed;
the acetous fermentation, becaufe during this part of the
procefs vinegar is produced; and the putrid or putrefac¬
tive fermentation, becaufe the fubftances are ftill farther
decompofed, and run into the ftate of putridity. But
thefe different kinds of fermentation might perhaps be
confidered merely as different ftages of the fame procefs;
for unlefs it is checked at certain periods, it runs on
through the different ftages without interruption. Ac¬
cording to fome, thefe three fpecies of fermentation do
not include all the changes which have the charaders
of this procefs to which vegetables are fubjed. To
thefe it has been propofed to add the faccharine fer¬
mentation, or that change which is induced on farina¬
ceous feeds by heat and moifture, which is the germina¬
tion of feeds or the procefs of malting ; and the colour¬
ing fermentation, or that procefs by which the colouring
matter of vegetables, as indigo, is developed, In the p0ur2
prefent fedion we proppfe to treat, x. Of the vinous
fermentation ; 2. Of the acetous or acid fermentation ;
3. The panary fermentation, or the formation of bread ;
and 4. Of the putrid fermentation.
I. Of the Vinous Fermentation.
23°°
1. The vinous fermentation, otherwife denominated Hiftory,
the fpirituous, has been fo called, becaufe the firft pro-
dud is wine, which by diftillation yields fpirits. Boer-
haave was the firft who direded his attention to trace
the caufes, and to obferve the phenomena of fermenta¬
tion. The fame fubjed was afterwards profecuted by
other chemifts, and much wras written on the nature and
manufadure of wine ; but till the difeoveries of mo¬
dern chemiftry, and efpecially the important one of the
compofition of water, nothing was afeertained wdth pre-
cifion concerning the nature of fermentation, or the
changes which take place on the fermenting fubftances.
To the experiments and refearches of Lavoifier on the
formation and decompofition of alcohol, chemiftry is
indebted for fome of the molt important fads with re¬
gard to the procefs of fermentation. 2^or
2. Certain conditions are neceffary to promote the Condition^--
vinous fermentation. The firft indifpenfable condition is
the prefence of fome faccharine matter. Experience,
has Ihewm that no vegetable fubftances are fufceptible
of this fermentation, wThich do not contain fugar. Thus,
the fweet juices of fruits are ufually employed in this
procefs; and particularly, for the produdion of wine,
the juice of the grape.
But fugar in a ftate of purity, or uncombined with
other fubftances, is not fufceptible of any change. A
certain quantity of water, therefore, is neceffary that
the faccharine matter may be in the liquid ftate. Wa¬
ter therefore, is one of the effential conditions of the
vinous fermentation ; and it feems neceflary that the
water ftiould neither be in too great quantity, nor de¬
ficient. In the latter cafe the fermentation is inter¬
rupted ; in the former k is promoted too rapidly, and.
is apt to be converted into the next ftage, the acetous
or acid fermentation. When the confiftence is too.
great, water muff be added, and when it is too fluid,..
the addition of fugar becomes neceffary.
Th-x.'
718
Decompofi- The vinous fermentation fcarcely commences, if the
Ve’temPerature helow 6o°, but at the temperature of
t ^ a^es' 70° the procefs goes on britkly.
But fugar and water alone do not ferment, without
the addition of fome other fubflances. In the liquid
exprelled from grapes, which has received the name of
muj}, there are, befides fugar, a portion of jelly, fome
glutinous matter, and tartar.
The contact of air has been confidered as one of the
requifites of the vinous fermentation ; but this is not
neceflary, on account of the fermenting liquid deriving
any addition from the atmofphere, for the procefs goes
on equally well, when it is excluded, provided the gafe-
ous bodies which are formed are permitted to efcape.
A large mafs is alfo favourable for promoting the
vinous fermentation. A fmall quantity of faccharine
matter fcarcely at all undergoes this change, while it
2302 funs fpeedily to the acid fermentation.
Phenomena 3. When the fubftances which are fufceptible of
of fermen- this fermentation, are placed in proper circumftances,
.ation. the procefs commences in a few hours, or a few days,
according to the temperature and the quantity of li¬
quid employed. The liquid is then agitated with an
inteftine motion it becomes thick and muddy ; the
temperature increafes, and carbonic acid gas is difen-
gaged. The liquid is increafed in bulk, and the fur-
face is covered with a voluminous, frothy matter,
which is owing to the carbonic acid gas adhering for
fome time to the vifcid matters in the liquid. The
quantity of carbonic acid gas difengaged during this
procefs is very confiderable. It begins to be evolved
at the commencement of the fermentation, and con¬
tinues till its termination. At the end of a few days,
or a longer or fhorter time, according to the tempera¬
ture and other circumftances, the fermentation ceafes.
Ihe liquid becomes tranfparent, the matters which
occafioned the muddinefs having precipitated to the
bottom, and from having a fweet tafte, it becomes
ftiarp and hot, and from having been vifcid and gluti¬
nous, it becomes more liquid and lighter. It is now
2303 converted into wine.
Decompofi- 4. Such are the phenomena of fermentation, from
iugar. 1 ^ and from the nature of the producft, very confi¬
derable changes muft have taken place on the compo¬
nent parts. One change has been obferved during .
this procefs ; namely, that the quantity of fugar is
always diminifhing, and, at the end of the procefs, is
entirely decompoled. The liquid is now more fluid
is fpecifically lighter, and has obtained a vinous tafte :
which new properties are afcribed to the formation of
alcohol which exifts in all wine. It would appear,
trom the experiments of M. Lavoifier, that it is the
urgar only which has fuffered decompofition. It is di¬
vided into two portions, one of which feparates, and is
carried off in the form of carbonic acid gas, while the
other, containing a great proportion o^ hydrogen, re-
rnams in the liquid, in the form of alcohol. ' Part of
the alcohol is carried off, and the alcohol which re¬
mains in the liquid is combined with the acids of the
wine and the colouring matter, from which it muft be
feparated by chftillatlon. The tartaric acid, it has alfo
been found, is partially decompofed during the pro
cefs, and a portion of malic acid is formed. It appears
xrom other experiments, that azotic gas is difenua
ged during this procefs, from which it is inferred'
CHEMISTRY.
. wines.
that fome others of the conftituents of the fermentingDecompofi-
liquid have been decompoied, fince fugar contains notlon L'f ve»
azote. getables.
5. There is great variety in the colour, flavour, ' 7?0 '
and ftrength of wines. Tbefe differences depend on Component
the nature of the foil and of the grapes, and very of-parts of
ten on the manner in which it is manufadfured. But'
the component parts of wine are generally iome acid
matter, alcohol, extractive matter, oil, and colouring
matter. It is be enafcertained by experiment, that ail
wines redden the tin&ure of turnfole. The acid which
exifts in greateft abundance in wine, was found by
Chaptal to be the malic acid 5 fome portion of citric
acid alfo has been detefted. Some wines, as cham-
paigne, contain a conliderable portion of carbonic
acid.
It is to a certain portion of alcohol contained in
wines that they owe their ftrength ; and, when wines
are fubje&ed to the procefs of diftillation, the alcohol
paffes over, and the fpirit which is thus obtained is
known by the name of brandy.
Ihe extraftive matter found in wines has been ob-Extradfive
ferved to diminifti in proportion to the age of the wines;matter*
as it feparates gradually from the liquid, and is preci¬
pitated to the bottom.
The flavour and odour of wines have been afcribed Volatile
to a fmall quantity of volatile oil; but this quantity is0ll‘
fo fmall, that no means hitherto employed have lucceed-
ed to obtain it in a feparate ftate. Wines are diftin-
guilhed by a peculiar colour, which is owing to the co¬
louring matter originally derived from the hufk of the
grape.
6. The juices of other fruits alfo afford materials for From^ther
feimentation, as that or cyder from apples, and perry fubltances.
from pears. Thefe are diftinguifhed from wines pro¬
perly fo called by containing a greater proportion of
mucilaginous matter. The juice of the fugar cane alfo
affords a fermenting liquid, from which is obtained by
diftillation the fpirit called rum. 2 Q$
7. Beer or malt liquors, as they are called in Bri-Beer,
tain, are fermented liquors obtained from farinaceous
feeds. Different kinds of corn are employed for the
purpofe of making beer. In Britain, barley is the mofl:
common grain in the preparation of this liquid. It is
firft fteeped in water, and afterwards thrown together
in a heap lor about 24 hours. During this period, in
confequence of the moifture which has been abforbed
by the grain, the procefs of germination commences,
oxygen gas is abforbed, carbonic acid gas is given out
and heat is evolved, while the radicle is protruded.
The procefs having advanced thus far, is checked by
flowly drying the grain. lor this purpofe it is fpiead
out on a floor, and in this ftate it is known by the
name of malt. It is afterwards expoled to heat, fully
dried, and ground to a coarfe powder. An infufion
is then made with water about the temperature of
1600, which is drawn off; more wrater is added till the
whole foluble part of the malt is extracted. This infu¬
fion, which has a fweet tafte, from having a portion of
faccharine matter, is called wort. After being boiled
with fome bitter fubftances, as hops, it is allowed to
ferment, and the procefs of fermentation is in a great
meafure fimiiar to that which has been already de-
Icribed of the fermentation of wine. The temperature
moft proper for this fermentation is about 6o°; the fer¬
mentation
C H E M I
Decompofi- mentation of wort is greatly promoted, and the quan-
c£i'Ie‘tity of the fermented liquor is more abundant with the
addition of yeaft.
230^ It has been found alfo, that the infufion of malt fer-
Fermenta- ments in clofe veflels, and equally well as when expofed
in dote v™ t0. the °pen air' During this fermentation carbonic
fels. * "acicl Sas is difengaged, which is mixed with a portion of
the wort. By the diftillation of the liquid obtained af¬
ter the fermentation has ceafed, alcohol is obtained j
the nature and properties of which have been already
defcribed in treating of that liquid under inflammable
fubftances.
S T R Y. 7,9
internal motion, fimilar to the other fermentations, Deeompofi-
in confequence of tne adtion of the component parts^ono^ Ve*
II. Of the Acetous Fermentation.
r. In treating of acetic acid, which is the pro¬
duct of this fermentation, we have already detail¬
ed the method propofed by Boerhaave for the ma-
nufa&ure of vinegar, and we have alfo defcribed
the properties of that acid. All that is now neceflary,
therefore, is fhortly to Hate the general phenomena
2310 which are exhibited during this fermentation. When
Phenome- wine or beer, which is the produft of the vinous
fermentation, is expofed to a temperature between yo°
and 90°, it becomes gradually turbid, the tempera¬
ture is mcreafed } it is agitated with inteftine motions,
and flaky fubflances are feen floating through it in all
direftions. The inteftine motions at laft fubfide, the
liquid becomes tranfparent by the matters which ren¬
dered it turbid precipitating to the bottom of the
veffel. The liquid has now affumed different pro-
2311 perties ; it is converted into acetic acid or vinegar.
Conditiom. 2. The conditions neceffary for the acetous fer¬
mentation are, a confiderable elevation of temperature,
and expofure to the air of the atmofphere. During
this fermentation oxygen is abforbed from the air, and
unlefs this abforption takes place, the fermentation
does not go on. It is neceffary that the fubftances to
be fubje&ed to this fermentation contain a certain pro¬
portion of extraflive matter j for if they are entirely de¬
prived of it, the procefs does not go on. Weak wines
or beer are more readily converted into vinegar than
ftrong wines j but when the procefs of fermentation
has commenced on the latter, the product is a ftronger
2312 and better vinegar.
Changes. . 3. In examining the products of this fermentation
it has been found that the malic acid and the alcohol
which previoufly exifted in the wine, have entirely
difappeared, fo that by their decompofition they have
contributed to the formation of the vinegar. Some
portion of the extractive matter alfo has been decom-
pofed. The acetic acid is formed alfo during the decom¬
pofition of many vegetable fubftances, either by means
of heat, or other chemical agents.
_ 2313
Nature of
this fer
III. Of the Panary Fermentation, or of Bread.
The fermentation which takes place in making
dentation ^read *s ^PP0^ to be peculiar j but the phenomena
lor1, and produft have not been fufficiently examined to be
able exaCtly to afeertain its nature. The procefs is
extremely Ample. Wheat flour, which is generally
employed, is formed into a pafte with w’ater, the propor¬
tions of which vary according to the age and quality
of the flour. After fome time it is agitated with an
 ^ ... ..... uvuun vji me component parts—
upon each other, the formation of new compounds,1
and the evolution of gafeous matter. Water is ef- v
lentially requifite in this fermentation. One of the
changes which have taken place during the procefs, is,
that the gluten which conftitutes a part of the flourj
has difappeared. It is entirely decompofed. This
matter has acquired a four difagreeable tafte, and if
it is made into bread, it is found unfit to be eaten.
A quantity of new pafte is then prepared, and a 2314
I'm all quantity of the old four pafte is added toLeaven’
it. This produces rapid fermentation. The four
pafte thus added, to promote the fermentation,
is called leaven, and the bread prepared by this
procefs has received the name of leavened bread; a
diftmCHon which has been known to mankind from
the earlieft ages of the world. It is frequently men¬
tioned in Scripture, in the Jewifti hiftory. It requires
forae attention to be able to determine the exaCt quan¬
tity of leaven neceffary for the proper fermentation of
the pafte. When it is deficient in quantity, the pro-
cefs of fermentation is interrupted, and the bread thus
prepaied is folid and heavy, and if too much leaven
be ufed, it communicates to the bread a difagreeable
four tafte. When the fermentation fucceeds, the pafte
fwells up, and is greatly enlarged in bulk, which k
owing to the formation of a quantity of gas, which is
confined within the mafs, by the vifeidity of the glu¬
tinous part of the flour.
Other fubftances are employed to promote the fer¬
mentation of pafte for the purpofe of making bread j
one of the moft common is the matter which col-
lefts on the furface of fermenting liquids from fari¬
naceous matters. This fubftance, which is called
barm or yeaft, is equally efficacious in producing fer¬
mentation, and is lefs apt to contaminate the bread 2315
with any difagreeable tafte. As it is collefted on Yeaft.
the. furface of fermenting beer, it was examined by
Weftrumb, and was found to contain a great variety
of ingredients. Befides the water, which was in
greateft proportion, it confifted of gluten, fugar,and mu¬
cilage, vvith a quantity of alcohol, and a fmall portion 2315
of malic, acetic, and carbonic acids. T he efl'ential Component
parts of barm or yeaft were found, by the fame che-Paits‘
mift, to be gluten mixed with a vegetable acid 3 and
therefore yeaft, which has been collefted and put
into bags ftrongly preffed and dried, by which means
it is obvious many of the component parts muff be
feparated, has been found equally fit for fermentation. 2317
2. When the pafte has undergone the proper de-Eakingof
greeof fermentation, it is formed into loaves, and in-breatk
troduced into an oven, which has been previoufly
heated. The fame temperature is as nearly as pof-
fible employed for the baking of bread. This is re¬
gulated by throwing a little flour on the bottom of
the oven. If it becomes black, without taking fire,
the oven is fuppofed to have acquired a proper tem¬
perature. This is found to be about 448*. 2313
3. If the fermentation has been properly condufted, Changes,
the bread during the procefs of baking enlarges in
bulk, becomes light and porous, and is full of eyes or ca¬
vities, in confequence of the extrication of the gas
which was confined by the vifeid, glutinous matter,
and now driven off by means of heat. It is alfo con-
fiderably
72T> C H E M I S T R y4
Decompofi-Ticlel'ably lighter, in confequcnce of the evaporation of commenced, accompanied with a fetid odour. They Compon-^t
tion of Ve-moj^ure . and it ftill continues to lofe weight by being are compofed of a mixture of carbonated hydrogen, Partsofve~
. getables- ^ keptj if it be expofed to the air. When it is firil re- carbonic acid and azotic gafes. After thele phenome- , getables- _
moved from the oven bread is diftinguifhed by a pe- na have continued for iome time, which is longer or v ^
culiar tafte and odour. Thefe are alio carried off by ffiorter, according to the nature and confidence of the
the evaporation of the moifture, unlefs it be prevent¬
ed by excluding the air. The component parts of
bread, fo far as they have been inveftigated, are quite
different from thofe of the flour, lo that thefe have
■2-,i9 undergone a chemical change.
Bread of 4.. Loaf bread is ufually made of wheat flour,
rye and po-which is found moll proper for this purpofe, in confe-
quence of the great proportion of gluten which it con¬
tains. Rye is alfo frequently employed in making
bread, but being deficient in the proportion of gluten,
it is lefs proper for the purpofe. Bread made of rye
has"~hot the lightnefs and poroufnefs of the wheaten
loaf. Parmentier has defcribed a procefs for mak¬
ing bread from potatoes. The potatoes are boiled
and reduced to a fine palte 5 but before they can be
converted into bread, it is neceffary to add an equal
weight of ftarch obtained from the fame root. In
this way a white, well-raifed bread, it is faid, is ob-
2320 tained.
Colouring q'0 a fermentation fomewhat fimilar is afcribed the
lion l" Pro^U(^ion °f the colouring matter of fome vegetable
fubftances, as for inftance that of indigo p in this how¬
ever, greater changes are effedled. In this procefs
the indigo plants are put into water, which is foon agi¬
tated with an inteftine motion. It is alfo accompanied
with an increafe of temperature, the produflion of a
frothy matter on the furface, and the evolution of an
-elaftic fluid, which is a mixture of carbonic acid and
carbonated hydrogen gas. During this procefs, the
colouring matter of the plant is feparated and preci¬
pitated, from which Fourcroy propofes to denominate
this the colouring fermentation,
/ ,
IV. Of the Putrid Fermentation of Vegetables.
Nature. If The putrefactive procefs is the laft ftage in the
decompofition of vegetable matters. In fome the parts
are completely feparated, and refolved into their pri¬
mary elements by the efcape of thofe fubftances by
which they were mutually held together. In others,’
new compounds are formed, by a new fet of attra&ions
2322 and combinations.
Conditions. 2. Several conditions are neceffary to promote pu-
trefa&ion. The firft requifite is water, without which
the procefs does not go on. When vegetables are kept
perfectly dry, they undergo no change. The contaft
of air is alfo neceffary, and a moderate temperature.
When the temperature is too high, the moiffure is
carried oft by evaporation, before the changes in
which this procefs confifts can be effe&ed ; but when
toe moifture is not carried off, the higher the tem-
2323 peruture, the more rapid is the putrefaction.
Phenome- 3. When vegetables are placed in proper circum-
ha‘ fiances to favour this procefs, the colour and confift-
ence are foon changed ; the texture is deftroyed
the fibres are feparated ; the foft and liquid parts fwell
UP and are covered with froth ; elaftic fluids are dif-
engaged, the temperature is increafed, and fometirties
fo high as to produce aftual inflammation. The gafes
which are difeugaged, are, after the procefs has fairly
vegetable matters, great part, it appears, has been dif-
fipated by evaporation. There remains a dark colour¬
ed Jubilance containing the more fixed materials of the
vegetable, as the earths combined with the acids and
part of the carbone.
4. In obferving the neceffary conditions, the pheno-changey.
mena, and the produCls the putrid fermentation of
vegetables, the influence of the numerous attraClions
of the different materials which enter into their com-
polition is manifeft. Part of the hydrogen combines
with the oxygen, and is carried off in the Hate of
water, part eicapes in the Hate of gas combined with
a portion of carbone, and another portion of hydrogen
unites with the azote of thofe plants which contain it,
and forms ammonia. A fourth part remains behind,
and communicates odour and colour to the refiduary
mafs. The carbone combines partly with the dif-
engaged hydrogen, partly with the oxygen, forming
carbonic acid, and part remains behind. The oxygen is
divided between the hydrogen and carbone, forming
compounds of which thefe elements are the bafe.
Sect. III. Of the Component Parts of Vegetables.
1. Having in the two former fe&ions given a fliort
view of the funflions and fpontaneous decompofition
of plants, we are now to confider the nature and
properties of thofe fubftances which enter into their
compofition. Some of thefe fubftances are obtained obtained
from plants, while.they continue to exhibit the phfi-by different
nomena of vegetation*, fuch are faccharine mattersProceffes*
obtained from the fap, which is extrafled by wound-
ing the bark and wood, without much feeming injury
to the health and growth of the plant 5 and fuch ’too
are gummy and refinous matters, which many plants
throw off by fpontaneofis exudation ; and which, fo far
from being injurious, is perhaps neceffary in fome de¬
gree to vegetation ; but in general, the fubllances form¬
ed during the procefs of vegetation, or which are con-
ftituent parts of vegetable matters, can only be obtained
by the deftruftion of the vegetable itfelf. Thefe are
procured by different proceffes, which w-e fhall fiiortly
defcribe, in treating of the nature and properties of
each individual fubftance.
2. The component parts of vegetables, fo far as theyEn^2a.
have been examined, and fufficiently charafterized by tion of fub-
diftinft properties, may be enumerated under the fol, fiances,
lowing heads:
1. Gum,
z. Sugar,
3* Jelly>
4. Acids,
5. Starch,
6. Albumen,
7. Gluten,
8. Extradlive matter,
9. Colouring ditto,
to. Bitter ditto,
11. Narcotic ditto.
12. Oil,
Component
Parts of
Vegetables.
2327
c
12. Oils,
13. Wax,
14. Camphor,
15. Caoutchouc,
16. Refins,
17. Gum-refins,
18. Wood,
19. Tan,
20. Suber,
21. Alkalies,
22. Earths,
23. Metals.
I. Of Gum.
HEM
Extraction 1. Gum exudes from many trees during the procefs
perties. « vegetation, in the form of a vifcid, tranfparent, in-
fipid fluid. T he finer kind of gum is obtained chiefly
from the mimofa nihtica^ a plant which is very common
in many parts of Africa. This gum is ufually dittin-
guilhed by the name of gum arabic. After it feparates
from the tree, the watery part evaporates, and the gum
remains behind. It has then fome degree of hardnefs,
and is lb brittle that it may be reduced to fine powder!
It retains its tranfparency, is generally of a yellow co¬
lour ; but, when pure, it is entirely colourlefs. It has
neither tafte nor fmell. The fpecific gravity is from
,3*8 to 1.481.
AAionof # Gum is not changed by expofure to the air, but
air and it is deprived of its colour by the adion of the fun’s light,
fceat. When it is expofed to heat, it becomes foft, fwells up,
gives out air bubbles, blackens, and is reduced to charcoal!
During this change it gives out very little flame, and is
greatly enlarged in volume. It readily diffolves in wa¬
ter. The folution is thick and adhefive, and well
known as a pafte, under the name of mucilage. This
folution is little difpofed to decompofition. By evapo¬
ration the whole of the gum may be obtained un-
2349 changed.
Of acids. 3. Gum is foluble in the vegetable acids without de¬
compofition. Sulphuric acid decompofes it, and con¬
verts it into water, acetic acid, and charcoal. With
the aiTiftance of heat, muriatic acid produces a fimi-
lar effedt. Oxymuriatic acid converts it into citric
acid.
Gum is foluble in nitric acid with the afliftance of
heat. . Nitrous gas is emitted during the folution, and,
when it cools, facladlic acid is depofited. Malic acid
appears at the fame time ; and by continuing the heat,
the gum is at.lafl: converted into oxalic acid. Four
hundred and eighty grains of gum digefled with fix
ouncesofnitricacid,afforded MrCruickfliank 210 grains
433° oxa^c ac*^» and fix grains of oxalate of lime.
Alcohol. 4* ^7 pouring alcohol into a mucilaginous folution,
the gum is precipitated, fo drat it is infoluble in this li-
2331 quid. It is alfo infoluble in ether.
Diftilla- 5. Mr Cruickftiank diftilled 480 grains of gum arabic
by expofing it to a red heat in a glafs retort, and ob¬
tained the following produ&s:
Acetic acid mixed with fome oil 210 grs.
Carbonated hydrogen and carbonic acid gafes 164
Charcoal
Lime and a little phofphate of lime 10
I S T R y. y2l
Thus the conftituent parts of gum are, oxygen, hy-Component
drogen, carbone, azote, and lime. Parts of
6. Befides gum arabic, the properties of which we VfcgetaMes’
have now defcribed, there are different fpecies of gum '
obtained from different plants, which, however, in their ron2.^u
general properties refemble gum arabic. In fome in-ents.
deed they feem to be different, but thefe differences have
not been diftin&ly afcertained. Gum tragacanth, theobuined
produce of the ajlragalus tragacantha, which is in the from other
form of vermicular maffes, is lefs tranfparent than gumPlants‘
arabic, lefs foluble in water, and more adhefive ; but
yields by diftillation fimilar products. Gum obtained
from the cherry and plum tree, is of a browniflr
colour,, fofter and more foluble in water, but feems
otherwife to poffefs nearly the fame properties as gum
arabic. °
7. Gum in the ftate of mucilage exifts in a great num-Mucilaga
ber of plants, and efpeciaily in the roots and leaves.ex fts in
It feems to be moft abundant in bulbous roots, as thofemany
of the hyacinth, which contain fuch a quantity that^
they may be.advantageoufly employed in place of gum
arabic. It is obtained alio in confiderable quantity
from many of the lichens, and moft of the fuci. Mu¬
cilage.is found in greateft proportion in young plants,
but this proportion diminifties with the age of the plant!
It is a principal conftituent in the leaves and roots of
efculent vegetables.
8. In the ftate of mucilage, gum conftitutes a nutri-Ufesf3^
tious aliment. On account of its adhefive properties
it is employed as a pafte, and by the callico-printers to
mix with their colours to give them confiftency. It is
well known as a component part of ink, to prevent
the precipitation of its more infoluble ingredients,
and it forms a very valuable article in the Materia
Medica.
II. Of Sugar.
. 14 Sugar exifts in every part of plants. It Is found In ad parts
in the roots, as thofe of the carrot and beet root ; Jn of plants,
the Items, as in the birch, the maple, fome palms, ’and
efpeciaily the fugar-cane ; in the leaves, as thofe of the
alh j in the flowers, the fruits, and feeds.
2. But the fugar which now forms a very extenfiveSugarcane,
article of commerce, and may be confidered as a necef-
fary of life, is entirely obtained from the juice of
the fugar-cane, which is chiefly cultivated in the
Eaft and Weft Indies, for the purpofe of extracting
the fugar. When the plants have arrived at their
full growth, which in the Weft Indies is in the courfe
of 12 or 14 months, they are cut down and bruifed 2,,8
by means of machinery j the juice which is collec- Manufac-
ted, is conveyed to iron boilers, wdiere it is boiled,
with the addition of a fmall quantity of quicklime, and
the impurities which rife to the furface are fcummed
oft. The boiling is continued till it acquires the con-
fiftence of fyrup, after which it is put into Ihallow vef-
fels, where it is allowed to cool and granulate. In ge¬
neral it is afterwards put into hoglheads, in which it is
imported to Europe, the bottoms of which are perfo-
rated, that the molaffes with which the fugar is mixed,
may be allowed to drain off. Sometimes it is put into
conical earthen veffels, open, at both ends, the bafe of
which is covered with moift clay, fo that the water
filters, through the fugar, and carries with it a greater
quantity of the molaffes and other impurities. The fu-
4 ^ gat
iion
Voi,. V. Part II,
480
72a
2339
Raw.
. 2340
{Properties,
■2341
Adi ion of
Ueat.
C H E M
Component gar thus treated, is called clayed fugar. It is not dif-
Parts of ferent from the former, but in being fomewhat purer.
■ etae^a:i es; rj',|le aJciition of quicklime in the boiling is fuppofed
to take up fome vegetable acids which prevent the
granulation of the fugar.
3. In this date the fugar is known in commerce by
the name of raw or Mufcovado fugar. It is ftill farther
purified by diflblving it in water, and boiling, when
the impurities which rife to the furface, are again re¬
moved ; a quantity of lime is alfo added, and it is clari¬
fied with blood. When boiled down to a proper con-
fiftency, it is put into unglazed earthen veflels of a
conical fliape, and inverted, to allow the water from
the moift clay with which the bafe of the cone is cover¬
ed, to pafs through the fugar, and carry off its impuri¬
ties. It is ftill farther purified by again diffolving it in
water, and fubjefting it to a fimilar procefs. Accord¬
ing to the number of proceffes to which it has been
fubjedled, it is called fingle or double refined fu¬
gar-
4. Sugar in this ftate is of a white colour •, it is well
known for its fweet tafte 5 it has no fmell. It has fome
degree of tranfparency when it is cryftallized. It is con-
fiderably hard j but it is brittle, and may be eafily re¬
duced to powder. It is phofphorefcent in the dark.
When the folution of fugar in water is concentrated,
it cryftallizes in the form of fix-fided prifms, terminat¬
ed by twro-fided fummits. The fpecific gravity of fu¬
gar is 1.4045.
5. When fugar is expofed to heat, it melts, fwells
up, becomes of a dark brown or black colour, emits
air bubbles with a peculiar fmell, which has been cal¬
led caramel. If a red-heat be applied, it fuddenly
burfts into flames, with a kind of explofion.
6. Neither oxygen nor azote have any a£Uon on fu¬
gar. It is not altered by expofure to the air. If the
air be moift, it abforbs a little water. There is no ac¬
tion between hydrogen and fugar. It is very foluble in
water 5 at fo low' a temperature as 48°, water diffolves
its own w’eight of fugar. This power increafes with
the temperature of the water. When water is faturat-
ed with fugar, it is called fyrup, which by concentra¬
tion and reft affords cryftals.
7. Sugar is foluble in many of the acids. It is de-
compofed by fulphuric acid ; when heat is applied,
the acid itfelf is decompofed, and converted into ful-
phurous acid j and a great quantity of charcoal is de-
polited.
Nitric acid a£ls on fugar with confiderable violence;
an effervefcence is produced, nitrous gas is emitted,,
and the fugar is converted into oxalic and malic acids/
Muriatic acid gas is flowly abforbed by fugar, which
becomes of a brown colour, and acquires a/Very ftrong
fmell. Sugar is inftantly diflblved w'hen it is thrown
in the ftate of powder into liquid oxymuriatic acid ; it
is converted into malic acid, while the oxymuriatic acid
is deprived of its oxygen, and reduced to the ftate of
muriatic acid. Alcohol readily diffolves fugar.' One
part of fugar is foluble in four of boiling alcohol.
Sugar alfo combines with the oils, and by this means
they may be mixed with water.
8. The fixed alkalies combine with fugar, and de¬
prive it of its fweet tafte ; but by adding fulphuric acid,
and precipitating the fulphate which is formed by means
of alcohol, the tafte is reftored. Some of the earths,
2342
iVater.
»343
Acids.
2344
Alkalies
I S T R Y.
as lime, combine with fugar, and form fimilar com- Component
pounds. Parts of
9. The fulphurets, hydrofulphurets, and phofphurets ? eS.‘
of the alkalies and fome of the earths, decompofe fugar,
and reduce it to a ftate fomewhat fimilar to gum. o
Mr Cruicklhank diffolved a quantity of fugar in alco- Ur£
hoi, and added to it phofphuret of lime. After expof-
ing the mixture to the open air for fome days, it was
evaporated, and water was added. There was no
evolution of gas, and the phofphuret ■was found con¬
verted into a phofphate. By filtering the liquid, and by
evaporation, a tenacious fubftance, refembling gum, re¬
mained behind.
10. By dilfilling fugar in a retort, the firft part of
the product is water, nearly in a ftate of purity. Ace¬
tic acid with a little oil next comes over, and afterward
empyreumatic oil. A bulky carbonaceous matter, which
fometimes contains a little lime, remains behind. Mr
Cruicklhank obtained by the diftillation of 480 grains
of pure fugar, by means of a red-heat,
Acetic acid and oil, 270 grs.
Charcoal, 120
Carbonated hydrogen and carbonic acid gafes, 90
480
Sugar, therefore, is compofed of oxygen, carbone,
and hydrogen. The proportions of its conftituent parts, parts,
according to Lavoifier, are the following :
Oxygen, 64
Carbone, 28
Hydrogen, 8
100
11. Sugar is alfo obtained from the juice of the m»-Maple^
pie tree in North America. The juice is extrafted fugar..
from the tree during the afeent of the fap in the fpring
feafon. A fingle tree, it is faid, yields from 20 to 30
gallons of fap, from which are obtained five or fix libs.
of fugar. It is manufaftured in the fame way as the
juice of the fugar-cane.
, It has lately been propofed to extradl fugar from the Eee2t^*
root of the beet ; and the attempt has been made, even
in the large way, by Achard of Berlin. The pro-
cefs which he folkwed is to boil the roots, cut them
into flices, and extraft the juice by preffure. The
roots are again put into water for 12 hours, and again
fubje&ed to the prefs. The liquids thus obtained are
filtered through flannel, boiled down to j-, and filtered
a iecond time. The remaining liquid is reduced by
boiling to ^ of the original quantity, and again filter¬
ed. It it then evaporated to the conliftence of fyrup.
The cruft which forms on the furface muft be broken
from time to time, and the fpontaneous evaporation
allowed to continue till the furface is covered with a
vifeid pellicle, inftead of the cryftals which firft form
on it. The whole mafs is then introduced into woollen
bags, and the mucilage is feparated by preffure. This
fugar, which in many refpedls poffeffes the properties
of common fugar, is contaminated with fome matter,
which communicates a bitter naufeous tafte. Many
other plants alfo contain fugar, either in the roots, the
fap, or the feeds. It exifts in wheat, barley, beans,
peafe,
/
234.9
Ufes.
C H E M I
■Component peafe, and otlier leguminous feeds, efpecially when they
Pans of are youngs in confiderable quantity.
. esetlt eS‘ 12 The ufes of fugar are fo familiar, that it is fcarce-
ly neceflary to enumerate them. In moll countries
where it can be obtained, it may be confidered in
fome meafure as a necefl’ary of life. It contains a great
proportion of nutritious matter. It is not changed by
the a£lion of the air, fo that it may be preferred for
any length of time. It is employed to preferve other
vegetable matters from putrefaftion, and fometimes it
is alfo advantageoufly applied to a limilar purpofe, in
the prefervation of animal fubftances.
23S°
Prepara¬
tion.
235*
Properties.
. 2352
Refenibles
gum.
2.3 S3
Acftion of
fcitric acid.
„ 2354
Eafily
•fenown.
Ill* Of Jelly.
i» Jelly is a foft tremulous fubllance which is obtain¬
ed from the juice of different fruits^ efpecially from
currants and bramble berries. The juice is extradled
by expreflion, and when it is allowed to remain at reft,
it coagulates. It is ftill mixed with a portion of a-
queous liquid, but this being poured off, and the coa¬
gulated part walhed with water, the jelly remains near¬
ly pure.
2. It is fometimes perfectly colourlefs, but frequen-
tly tinged with the colouring matter of the fruit. It
is of a foft, tremulous confiftence, and has an agreeable,
(lightly acid tafte. It diffolves readily in hot water,
and again coagulates on cooling. In cold water it is
nearly infoluble. It is deprived of the property of
coagulating by boiling* and then it is limilar to muci¬
laginous matter.
. 3. By coagulating the juices of the fruits which
yield jelly, feparating the liquid parts by filtration*
afterwards walhing the coagulum with cold water,
and by allowing the mafs to dry* it is found diminilhed
in bulk, and is tranfparent and brittle, having many of
the properties of gum $ fo that it has been fuppofed
that jelly is this latter fubftance in combination with
fome vegetable acid.
4. Jelly is converted into oxalic acid by means of
nitric acid. It combines readily with the alkalies j
and when it is diftilled, it yields a confiderable por¬
tion of acetic acid mixed with oil, but no percepti¬
ble quantity of ammonia, Jelly is found in all the
acid fruits, as in goofeberries, oranges and lemons.
IV. Of Acids.
1. The acids which exift in many vegetables are at
once recognized by their tafte, Thefe acids were for¬
merly denominated efvntial faits of vegetables, and it
was fuppofed, that all effential faits were the fame, and
were compofed of tartar, or vinegar. But Scheele’s
difeovery of the citric, malic, and gallic acids* which
poffefling diftindl properties from thofe of tartaric and
acetic acids* proved the contrary. Some vegetables
contain only one acid, as oranges and lemons, which
contain citric acid only. In other vegetables two
acids are found, as in goofeberries and currants* the
malic, and citric acids *, and fometimes three, as the
tartaric, citric, and malic acids* which exift together in
the pulp of the tamarind. As the acids which exift
m vegetables have been already deferibed, with the
method of preparing them, it is now only neceffary
to enumerate the vegetable acids, fpecifying at the
S T R Y. 723
fame time fome of the plants from which they are ob- Component
tained. Parts of
2. Acetic acid has been difeovered in the fap
fome trees, and in the acid juice of cicer arietinum.
In the latter it is mixed with oxalic and malic acids. Acetle.5
Acetic acid was detected by Scheele in the fambuetts
nigra or elder.
3. Oxalic acid exifts in combination with pot a ill, in Oxalic,
the leaves of the oxalis acetofella or wood-forrel. In
other fpecies belonging to the fame genus, and in fome
fpecies of rumex, it is in the ftate of acidulous oxalate
of potalh. Oxalate of lime has been found in the root
of rhubarb.
4. The following vegetable fubftances contain tar-Tartaric*
taric acid ; in which, however, it is combined with
potafti, in the ftate of acidulous tartrate of potafti.
In this ftate it is found in the pulp of the tamarind,
the juice of grapes, of mulberries, of rutnesc acetofa
or forrel, of rheum raponticum, or rhubarb, and of
agave americana. It is found alfo in the roots of triti-
cum repens, or couch-grafs, and in leontodoii taraxacum,
or dandelion.
5. Citric acid is found in the juice of oranges and Citric,
lemons, in the berries of two fpecies of vaccinium, the
oxycoccos or cranberry, and the vitis ideea or red
whortleberry, the prunuspadus, or bird-cherry,
dulcamara, bitter-fweet, or nightftiade, rofa canina, or
wild rofe.
6. Malic acid exifts unmixed with other acids, in Malic
the apple, the barberry, plumb, floe, elder, rowan, or
fruit of the mountain alh.
In the goofeberry, in the cherry, ftrawberry, cur-
fants and fome other fruits, malic and citric acids arc
found nearly in equal proportions.
Malic acid has been found mixed with tartaric
acid in the agave americana, and in the pulp of ta¬
marinds, along with citric acid. Vauquelin found it
combined with lime, forming a malate of lime, in the
fetnpervivum te&orum or houfe-leek j in three fpecies
offedum or ftone-crop* namely the album, acre, and
telephium; in different fpecies of crajfula and mefem-
bryanthemum, and in arum macu/atum.
7. Gallic acid is found in a great number of plants, Gallic,
and in them it exifts chiefly in the bark. The follow¬
ing are the relative proportions t>f the quantity of gal¬
lic acid in different plants, as they have been afeertain-
ed by Mr Biggin.
2359
2350
Elm
Oak cut in winter
Horfe-chefnut
Beech
Willow boughs
Elder
Plum-tree
Willow trunk
Sycamore
Birch
Cherry-tree
Sallow
Mountain alh
Poplar
Hazel
Alh
Spanilh chefnut
Smooth oak
Oak cut in fpring
Huntingdon or Lei-
cefter willow
Sumac
8
8
8
9
10
10
10
10
10
H
* Nitloi.
Jour. rii.
* P- 394- 4tc*
23d!
8. Benzoic acid is found in benzoin, balfam of To-Benzole,
lu and Peru, liquid flyrax, cinnaynon, and vanilla.
Fourcroy and Vauquelin fufpe£l that it exills in the
anthoxanthum odoratum, or fweet-feented grafs, which
communicates the aromatic flavour to hay.
4 Y 2 9. Pruffic
7-2+
Component
Pa its of
Vegetables.
2362
Pruffic.
CHEMISTRY.
2363
rliofpliorlc.
2364
Prepara¬
tion.
3365
Properties.
2366
Adtion of
heat.
3367
Of acids.
2368
Compofi-
tion.
9. Pruflic acid lias been found in the leaves of the
laurocerafus and peach, In bitter almonds, in the
kernels of apricots j and it is fuppofed that it exifts al-
fo in the kernels of peaches, of plums, and cherries.
It is obtained from the kernels of apricots by diftilling
water off them with a moderate heat ; and if lime be
added to the concentrated infufion of bitter almonds, a
pruffiate of lime is formed.
10. Phofphoric acid has been found in different
parts of plants $ but it is generally combined with
lime, forming a phofphate of lime. This fait exifts
in the leaves of many trees, in the aconitum napellus^
or monks-hood, and in all kinds of grain.
V. Of Starch.
1. If a pafte be formed of wheat flour and water,
and this be wafhed with additional quantities of water,
till it is no longer turbid, but comes off pure and
colourlefs, the mafs which remains becomes tenacious
and duftile. This is called gluten, which wdll be
afterwards defcribed. If the water with which the
pafte was wTa(hed be allowed to remain at reft, it de-
pofits a wdiite powder, which is diftinguiftied by the
name of fecula or Jiarch.
2. Starch is of a fine white colour, and is ufually
in the ftate of concrete columnar maffes. It has no
perceptible fmell, and fcarcely any tafte. It is little
altered by expofure to the air ; when it is expofed to
heat on a hot iron, it melts, fwells up, becomes
black, and burns with a bright flame. The charcoal
which remains, contains a little potaftt. When it is
diftilled, it gives out water mixed with acetic acid,
which is contaminated with oil. It gives out alfo car¬
bonic acid and carbonated hydrogen gas.
3. Starch is not foluble in cold, but forms a thick
pafte with boiling water, and when this pafte is allow¬
ed to cool, it becomes femitranfparent and gelatinous ;
it is brittle when dry, fomewhat refembling gum. If
this pafte be expofed to moift air, it is decompofed, for
it acquires an acid tafte.
4. Sulphuric acid diffolves ftarch flowly ; fulphurous
acid is difengaged, and a great quantity of charcoal is
formed.
Muriatic acid alfo diffolves ftarch, and the folution
refembles mucilage of gum arabic. When left at reft
a thick, oily, mucilaginous liquid appears above, and
a tranfparent ftraw-coloured fluid below. The odour
of muriatic acid remains, but when water is added,
it is deftroyed, and a ftrong peculiar fmell is emitted.*
Starch is alfo foluble in nitric acid, with the evolu¬
tion of nitrous gas. The folution affumes a green
colour,_ and when heat is applied, the ftarch is con¬
verted into oxalic and malic acids. Some part of the
ftarch, however, is infoluble in nitric acid, and when
this is feparated by filtration, and wafhed with water,
it has a thick oily appearance like tallow, is foluble
in alcohol, and when diftilled, yields acetic acid, and
an oily matter fimilar to tallow in odour and confift-
ence.
5. Starch is infoluble in alcohol, but is foluble in
the alkalies ; in pure potafh it fwells up, becomes
tranfparent and gelatinous, and is then fufceptible of
folution in alcohol. The component parts of ftarch
as appears by diftilling it, and by the aftion of re¬
agents, are oxygen, hydrogen, and carbone,
6. Starch exifts in a great number of vegetable fub- Component
fiances, but. chiefly in the roots and feeds, and parti- Parts
cularly thofe which are employed as food. Vegetables.
Starch, it is well known, may be obtained from the i^t)
potato. If the potato be grated down and wafhed Found in
with water till it comes off pure and colourlefs, this100ts and
water being left at reft, depofits a fine white powder, feedi,‘
which aflumes fomething of a cryftallized appearance, 2370
and is heavier than wheat ftarch. 0 a
Sago, which is well known, on account of its nutri- Sago,
tious qualities, is obtained from the pith of different
fpecies of palms, which grow within the tropics. The
ftem is cut into pieces, which are fplit into two $ the
pith is wafhed out with cold water, which being left
at reft, depofits the ftarch. The water is poured off,
and before the remaining mafs is fully dried, it is for¬
ced through a perforated veffel, and granulated, in
which ftate it is brought to Europe. 3373
Saloup, which is chiefly compofed of ftarch, is pre- Saloup.
pared from the roots of different fpecies of orchis. It
is moftly imported from Perfia.
Caffava, or caffada, is a kind of bread chiefly com- Caffava.
pofed of ftarch, which is much ufed as an article of
food in the Weft Indies. It is prepared from the
roots of the jatropha manihot. The roots are well
wafhed, grated down, and put into bags, which are
fubjefted to ftrong preffure. By this procefs the
whole of the juice is feparated. This juice, or fome¬
thing at leaft which it holds in folution, when taken
internally, is a deadly poifon to moft animals. The
matter remaining in the bag is dried and fifted, and
without any other addition, when it is fpread thin on
a hot ftone, it forms a cake, which is the caffada
bread, found to be of a very nutritious quality, in
confequence of the great proportion of ftarch which it
contains.
Some fpecies of the tribe of lichen contain a con- Lichen?
fiderable proportion of ftarch, as the lichen rangiferi-
nus, or rein-deer lichen, which affords food to the
rein-deer, and the lichen iflandicus which is formed
into bread by the Icelanders, and is found to be
extremely nutritious. The latter has lately been re¬
commended as a remedy in confumption ; but it pro¬
bably poffeffes no other virtue in the cure of that fatal
difeafe, than affording a great proportion of nutritious
matter in fmall bulk.
VI. Of Albumen.
I. The exiftence of albumen in vegetable fubftances
had begun to be doubted by chemifts, till it was late¬
ly difcovered, by Vauquelin, in the juice of the canca
papaya, ox papaw-trte, which grows in different coun¬
tries within the torrid zone. The juice which exudes
from this tree, was brought home in the liquid ftate,
mixed with an equal quantity of rum, and another
portion of the juice was in the ftate of extraft. The
firft was of a reddilh brown colour, was femitranfpa¬
rent, and had the odour and tafte of boiled beef. The
fecond was of a yellowiftt white colour, femitranfpa¬
rent, and of a fweetilh tafte ; had no perceptible
fmell, but was of a firm confiftence, and in the form
of fmall irregular maffes. When the dried portion was
macerated in cold water, it was almoft entirely diffol-
ved. When nitric acid was added, a copious white
precipitate was formed. This was the albumen in the
ftate
/
CHEMISTRY.
Component
Parts of
Vegetables,
2375
Refembles
animal al¬
bumen.
* Annal. de
Chim. xiiii.
p. 270. and
xlix. p. 304.
ftate of white flakes. When the extraft of this juice
was fubjetled to diftillation, it yielded carbonate of
'ammonia, a thick fetid, reddilh coloured oil, carbonic
acid, and carbonated hydrogen gafes, and there remain¬
ed behind a light carbonaceous matter; which, being
burnt, left a quantity of white allies, confiding almoft
entirely of phofphate of lime.
2. From other experiments to which this matter was
fubjefted by the fame chemift, from its folution in wha¬
ler, its coagulation by means of heat, its aftion wuth
the acids, the alkalies, metallic folutions, the infuflon
of nut-galls, and alcohol, he concludes, that it is pre-
cifely of the fame nature with animal albumen *.
VII. Of Gluten.
237*
Prepara¬
tion.
2377
Properties
2378
Ferments.
2379
Adtion of
acids.
23S0
Of alcohol
on fer¬
mented
gluten.
2381
Oi alkalies.
1. When a pafle is formed with flour and water, and
walked with more water till it paffes off pure and co-
lourlefs, a tenacious, dudlile, foft, elallic mafs remains
behind, wdiich is gluten.
2. This fubftance is of a gray colour, extremely duc¬
tile and tenacious, and poffeffes confiderable elaftici-
ty. It has a peculiar fmell, but no perceptible talle.
When it is fuddenly dried, it increafes much in vo¬
lume, and when it is expofed to heat, it cracks, fwells,
blackens, and burns like horn, exhaling a fetid
odour. When it is dillilled, it yields water impregna¬
ted with ammonia, and an empyreumatic oil 5 charcoal
remains behind. When moift gluten is expofed to the
air, it gradually dries, becomes hard, brittle, llightly
tranfparent, and of a brownilh colour, having fome re-
femblance to glue. When it is broken, it refembles
the frafture of glafs. It is infoluble in water, but retains
a portion of it, which it abforbs, and to which the ela-
fticity and tenacity are owing. It is deprived of thefe
properties by boiling.
3. When it is kept moift, it ferments with the evo¬
lution of hydrogen and carbonic acid gafes. An of-
fenlive putrid odour is given out at the fame time.
The gluten afterwards, if the procefs be allowed to go
on, exhales the fmell, and acquires the tafte of cheefe.
In this ftate it is found to contain ammonia and acetic
acid.
4. Gluten is foluble in all the acids. It is precipi¬
tated from this folution by all the alkalies, and is then
nearly in the ftate of extradlive matter, being deprived
of its elafticity. It is decompofcd by concentratedfulphu-
ric acid 5 hydrogen gas is emitted, and water, charcoal,
and ammonia are formed. It is alfo decompofed by ni¬
tric acid ; azotic gas is emitted, and if the heat be con¬
tinued, a portion of oxalic acid is formed. Yellow
coloured oily flakes ^are precipitated. After gluten is
fermented, it is foluble in acetic acid, and this folution
may be employed as a varnifh.
5. Gluten is infoluble in alcohol and in ether j but
if fermented gluten be triturated with a little alcohol,
and afterwards mixed with a quantity of the fame li¬
quid, part of it is diffolved and forms a varnifh, which
may be employed either for paper or wrood, for ce¬
menting china, or for mixing with vegetable colours
that are ufed as paints. Pieces of linen dipped in this
varnifh, adhere ftrongly to other bodies, and if lime be
added to the folution, it conftitutes a good lute.
6. With the afliftance of heat gluten is foluble in
the alkalies j and when they are much concentrated, it
is decompofed, and formed into a kind of foap, confift- Component
ing of oil and ammonia. i>arts of
7. It appears from the diftillation of gluten, and ? e"cytJ‘ey
from its fpontaneous decompofition, that it confifts of 23gz
oxygen, hydrogen, carbone, and azote. The vapour Compofi-.
which is evolved during the fermentation of gluten, tion.
blackens filver, from which it is inferred that fulphur
is one of its conftituent parts. From the properties
and compofttion of gluten, the refemblance between
this fubftance and animal matter is fufhciently obvi-
ous. . . „ . 2383
8. Gluten exifts in greateft abundance in wheat la wheat,
flour, but it is found in a great number of plants, and
in different parts of vegetables. It exifts in confider- 2384
able proportion in the juice of the leaves of many Leaves,
plants, as thofe of the cabbage, creffes, &c. When
this juice is procured by expreflion, filtered through a
cloth, and allowed to remain at reft, it depofits in the
courfe of fome days, a greenifti powder, which has been
called the green fecula of plants. This fecula is chief¬
ly compofed of gluten mixed wdth a refinous matter,
which gives it its colour, and a portion of woody fibre.
If this juice be expofed to the temperature of about
1 30°, the fecula coagulates in the form of large flakes.
It dries when feparated from the water, and affumes
the appearance of horn. When it is treated like glu¬
ten, it alfo acquires the fmell and tafte of cheefe.
Gluten has been found in acorns, chefnuts, and horfe-in feeds
chefnnts, in barley, rye, peafe, and beans ; in apples and fruit?,
and quinces ; in the leaves of fedum of different fpe-
cies, hemlock, borrage, faffron ; in the petals of the
rofe, in the berries of the elder, and in the grape.
None was detefled in the potato by Prouft, although
he found it in feveral other roots.
A fubftance which refembles the fibrina of the
blood, was found by Vauquelin in the juice of the
papaw-tree. When this juice is mixed with water, part
is diffolved, and part remains inloluble. The latter
has a greajfy appearance, becomes foft in the air, vifcid,
brown, and femitranfparent. It melted when thrown
on burning coals, while drops of greafe exuded. It
was entirely confumed, without leaving any refiduum.
But according to lome, this fubftance is exactly fimi-
lar to gluten, and therefore, is not to be confidered as
one of the conftituents of vegetable matter.
9. Gluten is one of the moft important of the com- ufes^
ponent parts of vegetable fubftances. It is one of the
chief ingredients in wheat, and to this it is owing
that wheat flour is fit for being formed into bread.
VIII. Of Extractive Matter.
2387
1. The word extraB was formerly employed to fig-Prepara-
nify the infpiffated juices of vegetables, but of late it tion.
has been limited to a peculiar principle poffeffed of dif-
tinCl properties. If faffron be infufed in water for
fome time, and if the infufion be filtered and evaporated
to drynefs, the refiduum is that fubftance to which the
name of extractive principle is given.
2. The following properties of extraCt were a^cer-pro2"5!8^
tained by Vauquelin. 1. All extraCts have an acid
tafte. 2. If a few drops of ammonia be added to a fo¬
lution of extraCt, a brown precipitate is formed, which
confifts of lime, and part of the extraCt becomes in¬
foluble. 3. Sulphuric acid difengages a penetrating
acid vapour, which is found to be acetic acid. 4. When
quicklime
26
CHEM ISTR
Component quicklime is added to a folution of extraftive matter,
Vegetables ammonia *s difengaged. 5. A folution of fulphate of
alumina without excefs of acid, being poured into a fo¬
lution of extraftive matter, and boiled, there is formed
in the liquid a flaky precipitate which is compofed of
alumina and vegetable matter, and rendered infoluble
in water. 6. Almoft all metallic folutions produce
a fimilar effedt. With muriate of tin an infoluble
brown precipitate is formed, which is compofed of the
oxide of tin and vegetable matter. 7. Oxymuriatic
acid poured into a folution of extra<5Hve matter, forms
a copious, dark yellow precipitate. Muriatic acid re¬
mains in the folution. 8. If wool, cotton, or thread,
be impregnated with alum, and boiled with a fo¬
lution of extra&ive matter, thefe fubftances become
charged with a great quantity of the extraftive fub-
flance, they aflume a fawn-brown tint, and the folu¬
tion lofes a great deal of its colour. The fame efFedt
is produced by immerfing the fubftances to be dyed in
a folution of muriate of tin. The effedl is ftill better, if
oxymuriatic acid be employed inftead of alum, or the fo¬
lution of muriate of tin. g. When extradfive matter
is diftilled in an open fire, it yields an acid liquid,
which contains a greater portion of ammonia than
when it is diftilled in the humid way with lime or alka¬
li. 10. When extradlive matter is diflblved in water,
and is left expofed to the open air, it is completely de-
compofed. The carbonates of potafti, of ammonia, and
of lime, and fome other mineral falts which previoufly
exifted in the extradlive matter, and are indeftrudtible
by putrid fermentation, remain behind.
3. It appears that extradlive matter is found in
greater proportion in old plants. It is found in dif¬
ferent parts of the plant. It frequently forms one of
the conftituents of the fap. It is this extradlive mat¬
ter which precipitates during the evaporation of the
fap, or when oxymuriatic acid is added to it.
Extradlive matter has been found in the bark of
many trees, and it is fuppofed that it exifts in all barks
which poffefs an aftringent property. It has been found
in the bark of the common willow, the Leicefter willow
the oak, and the elm.
Extradlive matter has been obtained from the in-
fufion of catechu, in which it is united with tan. If
the poxvder of catechu be repeatedly walked with wa¬
ter, the liquid which pafies off no longer precipitates
gelatine. The refiduum is extradive matter, of a red-
dilh-brown colour, has no fmell, but a flightly aftrin¬
gent taft-e. The folution in water is at firft yelloW'-
1 tli-brown, but acquires a red colour by expofure to
the air. Many of the metallic falts form a precipi¬
tate with the folution of this matter. Linen boiled in
it almoft extradls the whole, and becomes of a light
red brown colour. Extradlive matter foftens when ex-
poled to heat ; the colour becomes darker, but it does
not melt When it is diftilled, it yields carbonic and
carbonated hydrogen gafes, acetic acid, and a ftnall
portion of extradlive matter unchanged. A light por¬
ous charcoal remains behind. ' ' or
The infufion of the leaves of fenna is of a brown co-
lour, has a peculiar aromatic odour, and a bitter tafte.
When the air of the atmofphere or oxygen gas is
made to pap through this infufion, a yellow coloured
precipitate is formed. _ It is produced alfo by adding
£0 the lolution muriatic or oxymuxiatic acid. In this
ftate the extradlive matter has combined wuth oxygen, Coinponefif
and has aflumed a yellow' colour, and being no longer Part> of
foluble in water, it is precipitated. The tafte is flight- Vegetabiec»
ly bitter. It is foluble in alcohol, but when water is y_"-f
added, it k thrown down. It is foluble alio in al¬
kalies, and forms with them a deep brown folution.
When placed on burning coals, it gives out a denfe
fmoke, exhales an aromatic odour, and leaves behind a
fpongy mafs of charcoal. ■2393
Extradlive matter is obtained from the infufion ofPemviaa
Peruvian bark, which being united with oxygen, be-barkl
comes of a fine red colour. It is obtained by boiling
water on it, and by flow evaporation, and then diflolving
what remains in alcohol. By evaporating the alcohol,
the peculiar extradlive matter is depofited. The mat¬
ter thus obtained was of a brown colour, of a bitter
tafte, foluble in hot water and alcohol, but infoluble
in cold water. It is of a black colour when dry,
and brittle. It breaks with a polifhed fradlure. With
the addition of lime-water it was precipitated in the
form of a fine red powder, which combined with al¬
kalies, but is infoluble in water and alcohol.
IX. Of Colouring Matter.
)
I. Colouring matter is extra&ed from a number ofEx;ft3s11
2389
Exifts in
old plants.
2390
In the
bark.
2391
Catechu.
. 23S>2
Senna.
plants for the purpofes of dyeing, as from madder, car- many
thamus, brazil wood, logwood, yellow weed or refedaPiants*
luteola, fuftic or yellow-wmod, anatto, and indigo.
2. The colouring matter of madder, or rubra tine- M jj9S
torum, is foluble in alcohol. By evaporation it leaves 1 3 ***
a refiduum of a dark red colour. A violet precipitate
is formed in this folution by a fixed alkali. Sulphu¬
ric acid produces a fawn-coloured precipitate, and ful¬
phate of potafh, a beautiful red. Precipitates of dif¬
ferent fhades of colour are obtained with alum, nitre,
chalk, acetate of lead, and muriate of tin.
3. Carthamus (tinftorius) contains two colouringr
matters, the one yellow and the other red. The firft “***
only is foluble in water, but the folution is turbid. It
becomes^ tranfparent wdth the addition of acids j with
alkalies it inclines to an orange colour; a fawn-colour¬
ed precipitate is formed, and then the folutioh becomes
clear. Alum produces a dark yellow precipitate, but
■ not very copious. A flight tinflure is extrafted from
the flowers of this plant by means of alcohol, after
the whole of the yellow matter has been diflblved by
water. 7
. 4‘ Erazil wood, ox fernambouc, is much employed ~
m dyeing.^ A recent decoaion of this wood gives a woTd.
red precipitate inclining to fawn colour with fulphuric
acid. The liquid in which the folution was made re¬
mains tranfparent and of a yellow colour. With the
firft addition of nitric acid the tinaure firft paffes
to a yellow colour 5 but with a greater quantity, be¬
comes of a dark orange yellow and tranfparent, after
having depofited a matter fimilar in colour to the for¬
mer, but more copious. The fame changes take place
with the muriatic acid as with the fulphuric.
5. Logwood or Catnpeachy uW yields its colouring l0pwood,
matter to water and to alcohol, but more copioufly to
the latter. The tinfture of logwood, or the folution in
alcohol is of a beautiful red colour, inclining to violet
or purple.. Thefe different fhades are more obvious in
the decoaion in water. When the aqueous folution
C H E M I S
*399
Yellow
weed.
2400
Fuftic.
2401
£natto.j
Component left to itfelf, It firfl. becomes yellow, and then changes
Parts of t0 black, Xhe addition of acids produces a yellow
. .'colour: alkalies deepen the colour and reftore the
purple or violet. Sulphuric, nitric, and muriatic acids
throw down a light precipitate which feparates flow-
ly. Sulphate of iron communicates a bluifli colour
fomewhat refembling ink. A copious precipitate of a
limilar colour is formed at the fame time.
6. Yellow weed, or dyers weed {rcfeda luteola Lin.)
in folution in water yields a yellow colour Inclining to
brown. When it is diluted with a greater quantity
of water, the yellow colour which was more or lefs
bright changes a little to green. The colour becomes
paler with the addition of acids. It becomes deeper
by the aftion of alkalies.
7. Fuftic, or yellow wood, (rnorus tincioria, Lin.)
contains a great proportion of colouring matter. A
ftrong decodtion in water is of a dark reddifh-yellow
colour. When water is added to this folution the co¬
lour becomes orange-yellow. The liquid grows turbid
with the addition of acids. Alkalies render it much
deeper and nearly red.
8. Anatto is in the form of a dry hard pafte, exter¬
nally brown, and internally of a beautiful red colour.
It is prepared from the feeds of the bixa orellcma by
reducing them to powder, mixing them with water,
and allowing them to ferment. Anatto is more folu-
ble in alcohol than in water. With the addition of an
alkali the folution is promoted, and the colour inclines
lefs to red.
Beftde thefe, a great variety of other vegetable fub-
flances give out their colouring matter to water or al¬
cohol, and are 'employed in dyeing. To what has
now been faid, however, wm {hall only add a fhort
account of one of the moft important, namely indigo.
9. Indigo is a colouring matter which is obtained
from feveral plants, and has fome refemblance to- fecu-
la or ftarch. The indigo of commerce is chiefly ob¬
tained from the indigofera tindloria, a fhrubby plant
which is cultivated in the Eaft and Weft Indies, for
the purpofe of extrafting the colouring matter.
10. When the indigo plant has arrived at maturity,
it is cut down, and conveyed to large wooden veflels,
where it is covered wuth water, and mon commences a
fermentation. When the plant is cut down at the
period of its maturity, it produces a more beautiful
colour, but in fmaller quantity. If it be too late, the
quantity is ftill diminifhed, and the indigo is of a
bad quality. The putrefa£five procefs foon com¬
mences, and fucceeds beft about the temperature of
8o°. The water becomes turbid, and of a green co¬
lour. The fmell of ammonia and carbonic acid gas
are evolved. The fermenting procefs is finilhed in
the period of from 6 to 24 hours, according to the
temperature and ftate of the plant. The liquid is
then poured off into flat veffels, in which it is conftant-
ly agitated till blue flakes appear. With the addition
of a quantity of lime-water thefe flakes precipitate to
the bottom. A yellowilh liquid is poured off, and the
blue precipitate is colle&ed in linen bags, from which
the water drains off. When the matter in the bag has
acquired fufficient confiftence, it is formed into fmall
cakes, which are flowdy dried in the {hade. This is
the indigo of commerce.
2402
Indigo.
2403
Prepara¬
tion.
TRY. 727
I x. Indigo may be alfo extra6led from the tienum Component
Un&orhmi, or rofebay, a plant which grorvs in abund- vParts/),t „
ance in the Eaft Indies, from the leaves of which Dr . eA*‘t
Roxborough extracted it, by the following procefs. 24^4
He digefted the leaves in a copper veffel with water, From other
kept at the temperature of 160° till they aflumed aP^ant3,
yellowifh colour. The liquid becomes of a deep green j
it is then poured off, and Vvith the addition of lime-
water is agitated till the indigo is precipitated. To
produce one pound of indigo, two or three hundred
pounds weight of green leaves w'ere found neceffary ;
but this quantity varies according to the feafon and
ftate of the weather in which they are collefted. 2^c:.
12. The ifatis tinRoria, or woad, which is a BritifliFrom
plant, alfo yields indigo, by treating it in the fame wray woad.
as the indigo plant. 2406
13. The hiftory of indigo is curious. It was early H'ftory
known in India, but its value as a dye-ftuff was notot^*£c’
underftood in Europe before the middle of the 16th
century. But what is moft lingular, the ufe of this
fubftance was either reftri£ted or entirely prohibited in
different countries, from fome prejudice that its effefts
in dyeing wrere injurious. The ufe of it was prohibit¬
ed in England from the time of Queen Elizabeth till
the reign of Charles II. It wras alfo prohibited in
Saxony. It is deferibed in the edift as a corrofive
fubftance, and denominated food for the devil l In
France during the adminiftration of Colbert, the dyers
were reftridled to the ufe of a certain quantity. For
fome time after, indigo was generally employed as a
dye fluff in Europe, and was chiefly cultivated in the
Weft Indies, and fome parts of the American conti¬
nent. This indigo was generally preferred in the
market. What is now cultivated in the Eaft Indies
is found to be equal in quality.
14. Indigo is alight, friable fubftance, of a compaft Propertiea,
texture, and a deep blue colour. The lhade varies
from copper, violet, and blue tints. The lighteft indi¬
go is the beft. It is always contaminated with extra¬
neous matters. Bergman found in the pureft indigo
which he could procure, the following component
parts.
Pure indigo
Gum
Refin
Barytes
Lime
Silica
Oxide of iron
47
x 2
6
10.2
10.0
1.8
13.°
100.0
2408
Compofi-
tioa.
Other earths have been found in indigo. In fome fpe-
cimens Prouft detefled magnelia. 240$
15. Pure indigo is a foft powder of a deep blue co-Adlionof
lour, which has neither tafte nor fmell. When expofed heat*
to heat, it emits a bluilh-red fmoke, and then burns
away with a faint white flame. The earthy parts re¬
main behind in the ftate of afhes. It undergoes no
change by expofure to the air. It is infoluble in iva-
ter, but if kept fome time under it, a fetid odour is
exhaled, owing to fome change. *41©
16. Diluted fulphuric acid poured upon indigo, dif- Of acid*,-
folves
728
Component
Parts of
Vegetables.
2411
Effects of
different
fubftances
on liquid
blue.
. 2412
<Nitric acid
2413
Of alcohol.
2414
Alkalies.
C H E M I
folves only the earthy and mucilaginous matters j but
if concentrated fulphuric acid be added, in the propor-
_ tion of eight parts of acid to one of indigo, the latter
is diifolved with the evolution of heat, in about 24
hours. The mixture is black and opaque $ but if wa¬
ter be added, it becomes clear, and of a fine blue co¬
lour, producing various fhades, according to the quan¬
tity of water. This folution of indigo in fulphuric acid
is called liquid bluey or according to Bancroft, fulphate
of indigo.
Bergman made a great number of experiments on
the effeft of different fubftances on this folution, fome
of which we lhall now mention, in which the colour
was either changed, or entirely deftroyed. When it
was dropped into fulphurous acid, the colour which
was at firft blue, became green, and was at laft de-
flroyed. In diluted tartaric acid the colour became
gradually green, and was at laft converted into a pale
yellow. In acetic acid it became green, and was at
laft deftroyed.. In potafti, carbonate of potafh, foda,
ammonia and its carbonate, the colour became green,
and at laft difappeared. In fulphate of foda the folu¬
tion being diluted, after fome time became green. It
alfo became green in fulphate of iron, and at laft dif¬
appeared. In the fulphurets the colour was very foon
deftroyed. Black oxide of manganefe produced the
fame effeft. Thefe experiments have been mentioned,
to fhew that indigo is deprived either partially or to¬
tally of its colouring matter, by thofe fubftances which
have a ftrong affinity for oxygen. From this it is in¬
ferred that indigo owes its colour to oxygen j and
that it becomes green when it is deprived of it.
^ Concentrated nitric acid attacks indigo with fuch
violence, that it fometimes inflames it. By diluting
the acid, the adion is greatly moderated. 'The folu¬
tion becomes of a brown colour; cryftals appear, which
are fuppofed to be oxalic acid, and a brown vifeid fub-
ftance remains behind.
Muriatic acid diffolves indigo precipitated from ful¬
phuric acid, and forms a liquid of a dark-blue colour.
Ihe other acids, as the phofphoric, acetic, and tartaric,
exhibited fimilar phenomena. They readily diffolve in-
digo, which has been precipitated.
Oxymuriatic acid has little a£tion on indigo in
lubftance, but it deftroys the colour of it in the ftate of ’
iolution.
. 'I' Neither alcohol, ether, nor oils, have any ac-
tion on indigo. Common indigo, when digefted with
alcohoi and ether, communicates a yellow colour ; but
this, it is fuppofed, is owing to the folution of the refin-
ous lubftance.
. I.8, rhe folution of the fixed alkalies readily diffolves
indigo, when it is precipitated from its folution. The
coiour of the folution is at firft green, and is at laft dc-
ftroyed. Liquid ammonia and its carbonate produce a
imilar effeft, from which it appears, that indigo is de-
compofed by the alkalies. 6
19. Lime, water alfo diffolves indigo precipitated
from its folution. The colour is at firft green, becomes
gradually yellow; when expofed to the air, the erTen
returns, and at laft difanpears. S
20. Bergman fubjefted indigo to the procefs of diftil-
dtSs1-' fr°m 576 SralnS ^ °btained the foll™ing pro-
S T R
Carbonic acid gas «
Yellow acid liquid containing ammonia
Oil - .
Charcoal - .
»9
173
53
331
576
Component
Parts of
Vegetables,
2415
Compofi-
tion.
The component parts of indigo, therefore, appear to be
oxygen, carbone, hydrogen, and azote.
X. Of Bitter Matter.
1. A great number of vegetable fubftances are diftin-In d.fferen*
guiffied by a. very bitter tafte, fuch as quaffia, a fub-fuaftancesf
ftance tiled in medicine, gentian, hops, camomile.
1 his tafte is aferibed to a peculiar matter, called from
this property bitter matter. It may be obtained by in-
fufmg quaffia for fome time in water. This folution
which is of a yellow colour, has an extremely bitter
tafte, but no fmell. If the water be evaporated with a
moderate heat to drynefs, a browniffi yellow fubftance
which has fome degree of tranfparency and du61i-
lity remains behind. After fome time it becomes brit¬
tle.
2. When this fubftance, which has a very bitterPropSuea.
tafte, and a brownifti yellow colour, is heated, it fof.
tens, fwells and blackens, then burns away without
much flame, and leaves a fmall quantity of allies. It
is very foluble in water and alcohol. Nitrate of fil-
ver renders it turbid, and afterwards produces a yel¬
low precipitate.in the form of flakes. Acetate of lead
produces a copious white precipitate.
XI. Of Narcotic Matter.
1. A peculiar fubftance has been deteaed in opium, Found L
to which it is fuppofed the properties it poffeffes ofd'fferent
producing fleep, are owing. On account of this pro-^1115'
perty this fubftance has received the name of narcotic
matter. It is obtained from the milky juices of fome
plants, as thofe of the poppy, lettuce, and lome
others. Opium, which is extraaed from the poppy,
is prepared by the following procefs.
The heads of the papaver album or white poppy K
which is cultivated in India and different countries of^oSunT
the eaft for this purpofe, are wounded with a fharp
mftrument ; a milky juice flows out, which con¬
cretes, and is colkaed and formed into cakes.
2. In this ftate opium is a tenacious fubftance, of apJ^tle*
browniffi colour, has a peculiar fmell, and a difagree-
able bitter tafte. It becomes foft with a moderate
heat. It readily takes fire, and burns rapidly. By
the analyfis of opium, it appears to be compofed of
the fulpnates, of lime and of potaffi, extradtive matter,
gluten, mucilage, refinous matter, and an oil, befides
the narcotic matter, to which its peculiar’ properties
are owing.
3. By digefting opium in water, part of it is diffol-SepaSLi
ved,. and by evaporating the folution to the confiftence ot the nar-
of iyrup,. a gritty precipitate appears, which becomes cotic mat-
more copious with the addition of water. This pre-ter*
cipitate is compofed of refinous and extradlive matter
befides the peculiar narcotic matter which is cryftall
lized. When alcohol is digefted on this precipitate,
the refinous and narcotic matters are diffolved, and
the
dim,
xlv. 263.
2422
2423
Properties,
4424
A (ft ion »f
ether, Sec
»425
Of acids.
Component the extractive matter remaiiw behind. As the folu-
Parts of t;on cooiS) t}ie narcotic matter cryftallizes, but the cry-
ege^a:i ^ 'ftalg are coloured with a portion of refin. By repeated
folutions and cryilallizations it may be obtained tole-
*A™-de rablypure.*
If alcohol be digefted on the refiduum, it becomes
of a deep-red colour, the fame cryftals are depofited
Of alcohol. on cooling, and may be purified in the fame way
from the refinous matter with which they are conta¬
minated.
4. The narcotic matter, or as it is called by De-
rofne, the ejjential fait of opium, when properly puri¬
fied, is of a white colour, cryftallizes in right-angled
prifms, with a rhomboidal bafe, and has neither tafte
nor Imell. It is infoluble in cold water, and requires
400 parts of boiling water for its folution, from which
it is precipitated by cooling. The folution does not
redden the tindure of turnfole. It is foluble in 24
parts of boiling alcohol, and requires about 100 parts
when it is cold. When water is added to the folu¬
tion in alcohol, it is precipitated in the form of a
white opaque matter.
Ether and the volatile oils diftblve this fait with the
afliftance of heat j but on cooling it is depofited in the
form of an oily liquid, and fome time after cryftals ap¬
pear at the bottom of the velfel.
5. One of the moft decided charaders of this fub-
ftance is its eafy folubility in all the acids, and with¬
out the aid of heat. It is precipitated from thefe fo-
lutions by means of an alkali, in the form of w hite
powder. Pure alkalies increafe the power of its folu¬
bility in water, and the acids, rvhen not added in ex-
cefs, occafion a precipitate. When nitric acid is poured
on the cryftals reduced to a coarfe powder, it commu¬
nicates to them a red colour, and readily diflblves
them. When the folution is heated and evaporated,
it yields cryftals of oxalic acid in confiderable quanti¬
ty. The refiduum has a very bitter tafle.
6. When it is thrown on burning coals, it gives out
a copious flame. When heated in a fpoon, it gradu¬
ally melts like wax. Diftilled in a retort with a mo¬
derate heat, it melts, and afterwards fwells up, with the
evolution of white vapours, which condenfe on the
fides of the veflel, in the form of a yellow oily matter.
There pafles over, at the fame time, a little water im¬
pregnated with carbonate of ammonia. Towards the
end of the procefs, carbonic acid and carbonated hy¬
drogen gas, with fome ammonia, are difengaged.
There remains in the retort a light, fpongy, volumi¬
nous mafs of charcoal, which, by burning, gives fome
traces of potafti. The oily matter depofited in the neck
of the retort is very vifcid, and has a ftrong aromatic
odour, with a pungent, acrid tafte.
7. Derofne tried the effedls of this fubftance on ani¬
mals, and in very fmall quantity. The fymptoms
which appeared, when it was given to dogs, were ex-
a£!ly fimilar to thofe which are produced, when a large
quantity of crude opium is fwallowed. They were re¬
covered from its eft'efts by means of vinegar, which he
accounts for on the principle of the eafy folubility .of
this fubftance in acids.
5. From the effects of heat and of nitric acid on this
fubftance, it appears to be compofed of oxygen, hydro¬
gen, carbone and azote.
9. This narcotic fubftance is alfo found in the milky
You V. Part II.
CHEMISTRY. 72(J
juice, and in the extracts which are obtained from fe-Component
veral other plants, as from different fpecies of la&uca ^arts
or lettuce, hyofcyamus niger, or henbane. The leaves Vege_tablesf
of fome plants alfo produce fimilar effects, as thofe of
the deadly night/hade, fox-glove, and comum maculatum ^ ‘^
or hemlock, PpiU,m
found m
XII. Of Oils. other
2426
Of heat.
2427
Effects 0
animals.
2428
Compofi-
tion.
plants.
1. The nature, properties, and component parts of 2430
oils, have already been detailed, when treating of in-Fixe^*
flammable fubftances. Oils are of two kinds, fixed
and volatile. Fixed oil exifts chiefly in the feeds of
plants, as linfeed oil, almond oil, and rape-feed oil.
Fixed oil is alfo found in the pulp of fome fruits, as
in that of the olive. Fixed oils are found in thofe
feeds which have double lobes, or two cotyledons, and
in thefe they are mixed with a quantity of mucilage.
Thefe oils are extradted from feeds by expreffion and
boiling.
2. Volatile oils are found in all parts of plants, ex- Vohtile.
cepting the feeds. In fome plants they exift in the
root, or the ftem, and in others in the leaves, the
flower, the pulp and rind of the fruit. The peculiar
odour by which almoft all plants are diflinguifhed, is
fuppofed to be owing to a volatile oil. Thefe oils
are alfo extradied by expreflion, and fometimes by ftif-
tillation.
XIII. Of Wax.
1. Wax of which bees form their combs for con-Prepara-
taining honey, is colledted from vegetables j and a fi-tion.
milar fubftance being found in different parts of plants,
it is to be confidered as vegetable matter. The var-
nifti with which the upper lurface of the leaves of fome
trees is covered, pofieffes the properties of bees ivax.
If the bruifed leaves are digefted in water, and after¬
wards in alcohol, till the foluble part is extracted, and
the refiduum be mixed with 6 times its weight of a folu¬
tion of ammonia, and after maceration, the folution be¬
ing poured off and filtered, diluted fulphuric acid be
added in excefs to faturate the alkali, conftantly ftirring
it, the varnilh precipitates in the form of a yellow' pow¬
der. It is then to be waftied with water, and melted
with a moderate heat. This fubftance is wax. 243i
2. Pure wax is of a white colour, has no tafte, and'Properties,
fcarcely any fmell. The aromatic fmell of bees wax
is owing to fome fubftance with which it is mixed, for
it is entirely removed by expofure to the air, when the
colour at the fame time djfappears. Pure wax under¬
goes no change by expofure to the air. The fpecific
gravity is 0.96. It is infoluble in water.
3. Wax becomes foft by the application of heat. Acfbon^f
Unbleached wax melts at the temperature of I42°.heat.
When it is pure it requires the temperature of 1550, and
then melts into a colourlefs, tranfparent fluid. By in-
cxeafing the heat, the wax boils and evaporates j with a
red heat the vapour takes fire, and burns with a bright
flame.
2435
4. The acids have fcarcely any aftion on wax. It Acids,
is bleached by means of oxymuriatic acid, but no other
effeft is produced.
5. Wax is foluble in boiling alcohol. It requires A;c^o|
20 parts of alcohol to difiblve one of wax, and as the&.c.
folution cools, the greater part is precipitated. With
the addition of water the whole is thrown down. With
4 Z the
730
Component
Parts of
Vegetables.
CHEMISTRY.
4437
Alkalies.
4438
Competi¬
tion.
the affiftance of heat ether diffolves wax nearly in the
fame proportion, but on cooling it is alfo precipi¬
tated. •
Wax is foluble in the fixed oils with the aid of heat.
This compound is known by the name of cerate, which
is much employed to form plafters for drefling wounds.
It is foluble alfo in fome of the volatile oils, as thofe of
turpentine, with the afliflance of heat. As the folu-
tion cools, part of the wax is precipitated.
6. Wax combines with the fixed alkalies, and forms
with them fubflances fimilar to foap.
7. According to the analyfis of Lavoifier, wax is
compofed of
Carbone,
Hydrogen,
82.28
17.72
100.00
4439
Butter of
2440
Obtained
from m
plants.
8. When wax is difiilled with a temperature above
2120, water comes over, fome acid, and a little fluid
and odorous oil. The oil in the courfe of the procefs
becomes thicker, and at lafl: affumes the confiftency of
butter; and hence it has been called butter of wax.
This fubftance by repeated diftillation is converted in¬
to a volatile oil. A coaly matter remains in the re¬
tort.
9. Wax is extracted from a number of plants, pof-
plantsmany different degrees of confiftency, as that from the
cacao, called the butter of cacao ; from the croton febi-
fera, called the tallow of croton ; and the myrtle wax
extrafted from the myrtca cerifera, or candle-berry
myrtle of America. The myrtle wax is obtained from
the berries of this plant. They are colle&ed and put
into a kettle, and covered with water to the depth of
half a foot. Heat is applied, and the berries are pref-
fed againft the fides of the veffel. The wax melts, and
fwims on the top. It is collected, paffed through a
cloth, dried and melted again, and then caft into cakes.
The wax, it appears, exifts chiefly in the outer cover¬
ing of the berries. Myrtle wax is of a pale-green co¬
lour ; the fpecific gravity is 1.015. When heated to
melts ; with a ftronger
444 f
Extraction
2442
Properties.
4443
Adtion of
heat.
the temperature of 109^, it
heat it burns, giving out a white flame with liule
imoke ; an agreeable aromatic odour is at the fame time
emitted. In its other properties it refembles bees¬
wax.
Prouft has detected wax in the rind of plumbs,
oranges, and fimilar fruits, and in the green fecula of
many plants.
XIV. Of Camphor.
1. Camphor is obtained from the laicrus catnphorata,
a fpecies of laurel which grows in China and Japan!
It is extracted by fublimation in an iron pot. The Dutch
afterwards purify it by a fecond fublimation.
2. It is a white, brittle fubftance, poffefling a hot
acrid tafte. The fpecific gravity is 0.9887. It is not
altered by expofure to the air, but it is fo extremely vo-
ktile, that it difappears entirely if left in an open
yeffel. It cryftallizes by fublimation in clofe veffels
in the form of hexagonal plates or pyramids. It is
inloluble in water, although at the fame time it com¬
municates fome of its odour.
3* When a heat about the temperature of 200° is
fuddenly applied, it melts, and then is volatilized. It
readily catches fire, and burns with a bright flame, with- Component
out leaving any refiduum. It even burns on the fur- f’arts °t
face of water. When a fmall quantity of camphor in Vegc^abici7
a ftate of inflammation is introduced into a large glafs ^
veffel filled with oxygen gas, it burfts out into a vivid
flame 5 the infide of the veffel is covered with a black
powder, and a gfeat deal of carbonic acid gas is dif-
engaged. If a little water has been previoufly put in¬
to the veffel, it is impregnated with carbonic and cam¬
phoric acids. 2444
4. Camphor is foluble in the acids, but wdth the ad-Acids‘
dition of water or an alkali, it is precipitated unchan¬
ged. Camphor in fulphuric acid forms a red folution j
in nitric acid, a yellow folution, which was formerly
called oil of camphor. By the repeated diftillation of
nitric acid off camphor, it is converted into camphoric
acid.
Sulphurous acid, muriatic acid, and fluoric acid, in
the ftate of gas, diffolve camphor. If oxymuriatic
acid gas be made to pafs into a folution of camphor in
nitric acid, it is immediately changed to a rofe colour,
and inftantly afterwards it becomes yellow7, which is
permanent during the procefs. When water is added
to the folutions of camphor in acids, it is feparated.
Camphor is alfo foluble in water impregnated with car¬
bonic acid gas, and in acetic acid. The latter com¬
pound conllitutes Henry’s aromatic vinegar.
5. Alcohol readily diffolves camphor, but it is pre¬
cipitated with the addition of water. By diluting
alcohol which holds camphor in folution wdth water,
juft fo much as not to precipitate the camphor, the lat¬
ter cryftallizes in the form of feathers. The fixed and
volatile oils diffolve camphor with the afliftance of
heat, but on cooling the camphor is precipitated, and
cryftallized, as in the folution with alcohol.
6. Camphor communicates to the alkalies a little of Alkalies!
its odour, but is not otherwife foluble in thefe bo-
dies. „ ,
7. According to the analyfis of Bouillon Lagrange, Compoil-
by diftilling one part of camphor with two of alumina,Uon*
formed into a pafte with water in a glafs retort, the
component parts of camphor are carbone and hydro¬
gen j the proportion of carbone being much greater
than in oils.
In the courfe of the diftillation, he obtained a vola-Oil ^cam-
tile oil, of a golden yellow colour, wdiich floated on the P^or.
furface of the water in the receiver. It had an acrid
burning tafte, and aromatic odour, fimilar to that of
thyme or rofemary. 244g
8. Camphor has been dete&ed in many other plants. Eour.a in
It has been extra&ed from the roots of thyme and maiiy
fage, and in thefe plants it feems to be combined withplams<
volatile oil. If the oil be expoled to a temperature be¬
low 540 in the open air, it evaporates, and the camphor
cryftallizes. It may be alfo obtained by diftilling the
oft in a water bath, under the temperature of 21 2°, till
a third part of the oil paffes over. Part of the cam¬
phor is found cryftallized in the veffel, and by repeat¬
ing the procefs, the whole may be extra&ed from the
oil. By mixing the camphor w ith a little dry lime
and fubliming it, it may be purified.
XV. Of Caoutchouc.
I. Caoutchouc is a foft elaftic fubftance, chiefly ob-Hiftoy?
tained
M50
Prepara¬
tion.
*451
Properties,
245*
Adtion of
iieat.
C H E xM I
Component talned from tlie Infpiflated juice of two trees, the hcevea
Dart' of caoutchouc and jatropha elajiica, which are natives of
Vegetables. 3out]1 America. This (ubftance was firft brought
from America about the beginning of the i8th cen¬
tury. It is called by the inhabitants of EfmeraUas, a
province of Quito, heve, and by the natives of the pro¬
vince of Mainas, caoutchouc.
2. It is extrafted by making incifions in the bark of
the tree. A milky juice flows from it, which is col-
le6ted in proper veffels. The juice is then applied,
one ftratum above another, on earthen moulds, and fuf-
fered to dry in the fun, or before a fire. Various
figures are formed on the furfaces of the different
pieces by means of a pointed inftrument. They are
then expofed to fmoke, and when perfe&ly dry, the
moulds are broken. In this ftate it is brought to
Europe. It is generally in the ftrape of bottles, but
fometimes in other forms.
3. When caoutchouc is pure, it is of a whitilh co¬
lour j it is foft and pliable like leather, extremely elaf-
tic, and pofleffes great tenacity. The fpecific gravity
is 0.9335.
4. When caoutchouc is expofed to heat, it readily
melts into a matter of the confiftence of tar. It
burns with a bright white flame, and diffufes a fetid
odour.
5. Sulphuric acid decompofes caoutchouc ; charcoal
is precipitated, and the acid is partially converted in¬
to fulphurous acid. It is alfo decompofed by nitric
acid j carbonic acid gas, azotic gas, and pruflic acid
gas are difengaged, and oxalic acid is formed. Muri¬
atic acid has no action upon it j but if oxymuriatic
acid is poured upon the milky juice, the caoutchouc is
immediately precipitated, and the acid is converted
into muriatic acid. If a given quantity of air be con¬
fined in a veffel over a quantity of this milky juice, the
oxygen of the air is abforbed, and a pellicle of caout¬
chouc is formed on the furface, from which it appears
that the formation of caoutchouc is owing to the com¬
bination of its bafe with oxygen.
6. Caoutchouc is infoluble in alcohol. It is folu-
ble in ether, but it is neceflary that the ether be pre-
vioufly walked with water. By this treatment it is
formed into fyringes, catheters, and other inllruments.
It is foluble in the volatile oils, but it remains fome-
what glutinous after the evaporation. A mixture of
volatile oil and alcohol forms a good folvent for caout¬
chouc, and in this ftate it may be employed as a var-
nifh for paper or fluffs. A varnifh may alfo be form¬
ed with it, by diffolving it in boiling wax. It is
alfo foluble in reftified petroleum, and when the fo-
lution is evaporated, the caoutchouc remains unchan-
sed- . . . , .
7. According to fome, caoutchouc is infoluble in the
alkalies ; but according to others, all of thefe bodies
are capable of diffolving it.
8. By diftillation caoutchouc yields ammonia, and
from this, and its decompofition by means of fulphuric
and nitric acids, its conftituent parts muft be carbone,
hydrogen, azote, and oxygen.
9. Caoutchouc has been detefted in different parts
of many other plants, but it is mixed with refinous,
gummy, and extraftive matters. It has been found
*453
Alcohol.
*454
Alkalies.
*455
Compon-
tion.
2456
Found in
different
vegetable
S T R Y. 731
flic. It has alfo been extra^Ied from the Component
intevrfolia or bread-fruit tree, the urccola elajiica, and
ficus itidica.
Parts of
Vegetables.
XVI. Of Refins.
*457
fubltances. in different fpecies of the mifletoe, in opium and ma-
1. Refinous bodies form a very numerous clafs of ve-Natuie of.
getable fubftances. When volatile oils are expofed to
the air, they become thick after a Ihorter or longer
time, and are then found to be converted into a rfn.
The oil abforbs oxygen from the air, and is deprived of
part of its carbone, wrhich combining with the oxygen
of the atmofphere, forms carbonic acid. Refinous
fubftances, therefore, are generally confidered as vo¬
latile oils faturated with oxygen. The general pro¬
perties of refinous fubftances are the following. *45^
2. They are folid, brittle, and commonly of a yellow-^rolit:i:Ues'
iftr colour, with fome degree of tranfparency. The tafte
refembling volatile oils, is hot and acrid. They have
no fmell. The fpecific gravity is from 1.0180 to
1.2289. -AH refinous bodies are eleftrics, and when
excited by friffion, the eleftricity is negative j hence
it is called ref nous ele&ricity. 245$
3. They melt by being expofed to heat, and burn ^Aionof
w-ith a yellow flame, giving out a great quantity 0fiieat'
fmoke. Refins, are infoluble in water. 2460
4. Refinous fubftances are foluble in nitric acid; Acids,
part is precipitated by the addition of water, and the
whole by means of the alkalies. With the afliftance
of heat they are all foluble in alcohol, and in fulphuric
ether. Refins are foluble in fome of the fixed oils, and
alfo in volatile oils. 2461
5. Refinous fubftances have been found to be folu-^kahes*
ble in the fixed alkalies.
6. We (hall now enumerate fome of the refins
which are beft known. 24^2/
Rtfn.-~This fubftance is extrafted from different Rofin.
fpecies of the fir, and the refinous matter obtained
from it has received different names. That procured
from the pinus fylvefris is the common turpentine ;
from the pinus larix, Venice turpentine ; and from the
pinus bajamea, balfam of Canada. The turpentine is
obtained by ftripping the bark of the trees } a li¬
quid juice flows out, which gradually hardens. This
juice confifts of oil of turpentine and rofin. By diftil-
ling the turpentine the oil paffes over, and the rofin
remains behind. By diftilling to drynefs common
rofin is obtained. When water is added, while it is
yet"fluid, and incorporated by agitation, what is called
yellow rofin is formed, - 246$
Pitch—-Is a refinous juice obtained from the pitch.
pinus picea, or pitch pine. It is purified by melt¬
ing and fqueezing it through linen bags, and it
is then known by the name of xvhite or Burgundy
pitch. White pitch mixed with lamp-black forms black
Pltch- ... . 2464
Mafic.—This is a refinous fubftance obtained fromjy^ftic,
the pifacia lentifcus, a tree which grows in the Le¬
vant. The fluid wTich exudes from the tree, concretes
into yellowiftr femitranfparent brittle grains. It has
little tafte, melts and exhales a fragrant odour when
heated, and readily diffolves in alcohol and fixed oils.
It contains a little volatile oil.
Sandarac.—This refinous fubftance is extracted from 2465
4 Z 2 theSaildarac*
732
Component
Parts of
Vegetables,
CHEMISTRY.
2466
Labdanum
2467
T5ragons-
blood.
2468
Anime.
2469
Copal.
2470
Yarnilh.
2471
Elemi.
2473
Balm of
Gilead.
the juniper. It is a fpontaneous exudation from this
plant in the form of brown tears, which are femitranf-
parent and brittle.
Labdayum, or Ladanum.—This is the produce of
the cijlus creticus, a Ihrub which grows in Candia. It
is the exudation of a vifcid juice, which concretes by
expofure to the air. It has a fragrant odour and a
bitter tafte.
Dragons-blood.—This refinous fubftance is a pro¬
duction of the draccena draco, and fome other plants.
It is of a dark-red colour, opaque and brittle. The
powder is of a crimfon colour. It melts when it is
heated, and readily burns. It has no tafte, is infolu-
ble in water, but foluble in alcohol, to which it com¬
municates a crimfon colour. It is alfo foluble in the
fixed oils, and gives them a red colour.
Refma anima.—This refin is the produce of a fpecies
of hymctuta, or locuft tree, a native of North Ame¬
rica. It is foluble in alcohol, and is employed as a
varnifh.
Copal.—This refinous fubftance is obtained from a tree,
the rhus copal/itium, a native of North America. The
copal moft preferred is brought from Spanifti America.
It is a light brown, tranfparent fubftance. It melts
when heated, but is not diredly foluble in alcohol, or
in oil of turpentine, and it is with difficulty foluble
in fixed oils. Copal forms an excellent varniffi. In¬
deed it is one of the beft that is known for beauty and
durability.
If copal be treated with oil of turpentine in a clofe
veffel, from which the vapours are not allowed to ef-
cape, they exert a great preffure, which prevents the
boiling, and thus the mixture acquires a higher tem¬
perature. A confiderable portion of the copal is thus
aiiTolved, and with the addition of a little poppy oil
it forms an excellent elaftic varnilh.
If copal be kept melted till a four-fmelling aroma¬
tic odour ceafes to proceed from it, and if it be then
mixed with an equal quantity of linfeed oil previoufly
rendered colourlefs by expofure to the fun, it com¬
bines with tlie oil, and thus forms a varniffi. The fub-
ftances varniffied with this preparation mull be dred in
the fun.
Copal may be diffiolved in alcohol, by previoufly
riiilolvmg half an ounce of camphor in 16 ounces of
alcohol. I his folution is poured on 4 ounces of copal
in a matrafs, which is flopped with a cork, and per¬
forated with a pm. When the copal is nearly diflblv-
ed, the procefs is Hopped, and the matrafs allowed to
cool before the cork is removed. This folution forms
a colourleis varmih.
Copal, ft is faid, may be diffolved in alcohol, by
expofing it to the aftion of the vapour. This procefs
s conduaed by boiling a quantity of alcohol in the
bottom of a veffel, at the top of which a piece of
opal is ufpended. During the procefs the copal fof-
tens and falls down like oil into the alcohol.
A W—Thft refinous fubflance is the produce of
Zc\ .a tree which grows in the Eaft
and \\ eft Indies It is femitranfparent, of a pale yel¬
low colour, foftiffi, and hardens by keeping It has
a ftrong fragrant fmell, and when diftilled it yields a
fragrant oil. 7 CAUS a
Opobalfamum, or balm of G/W—This refin is pro¬
cured from another fpecies of amyris, the Gileadenfis,
a tree which is a native of Arabia. The beft kind, Component1
which is highly valued by the Turks, is never feen in ?arts ot
Europe. Vegetable?.
Copaiva, or balfam of Copaiva.—This refinous fub- V '
ftanceis obtained from the copaivaofficinalis, a tree which r 2473
is a native of South America. It exudes by wounding °l5aiva'
the trunk of the tree. It is tranfparent, of a yel-
lowiffi colour, has a pungent tafte and an agreeable
imell. It is at firft of the confiftence of oil, but after¬
wards becomes as thick as honey. By diftillation the
volatile oil, with which it is mixed, may be feparated,
and the refinous matter remains behind.
This refin is the produce of the guaiacum Guaftc.4
officinale, a tree which is a native of the Weft Indies.
I he refin exudes fpontaneoufly in tears, but it is chiefly
obtained by cutting the wood into billets, and boring
them longitudinally. When one of thefe is heated on
the fire, the refinous matter is melted, and runs through
the hole as the wood burns. This refin is of a brownifli-
yellow colour, and has fome degree of tranfparency.
It is foluble in alcohol, and has neither fmell nor tafte.
It melts when heated, and when it is thrown on hot
coals, it diffufes an agreeable odour. When fwallow-
ed in the ftate of powder, it produces a ftrong fenfa-
tion of heat in the throat.
Lac. This refinous fubftance is obtained from the Lac.
ci oton lacciferum. It is a of deep red colour, wfith
fome degree of tranfparency. It is the bafis of the
finer kinds of fealing wax, and is employed as a var-
niffi.
Amber.—This fubftance poffeffes many of the pro- Amber,
perties of the refins, and it has been confidered by
fome of vegetable origin. It is a brittle hard fub¬
ftance, tranfparent, fometimes colourlefs, but often
yellow or deep brown. The fpecific gravity is 1.065,
It has neither tafte nor fmell, except when it is heat¬
ed, and then it becomes foft, and gives out a fragrant
odour. It burns with a ftrong heat, leaving only a
fmall refiduum. It is infoluble in water, but alcohol
drffolves a fmall quantity of it. When the folution is
concentrated, it becomes milky with the addition of wa¬
ter. The precipitate which is formed is a refinous
fubftance. It is foluble in the fixed alkalies at a boil¬
ing temperature. 2477
. Sulphuric acid converts amber into a black refinous Eftt.a of
mafs. It is alfo foluble in nitric acid. aci<4s‘ g
By the diftillation of amber, carbonic acid gas and Diftiflation.
carbonated hydrogen gas, an acid liquor, and an oil,
which is at firft thin and tranfparent, but afterwards
darker and thicker, is obtained. Succinic acid fublimes
totvards the end of the procefs. 2479
. When amber is roafted, it becomes foluble in the Varnifh.
oils, and forms a varniffi. This varniffi may be form¬
ed by fpreading the amber on a flat-bottomed iron-
pan, and expofing it to heat till it melts. It is then
covered up, and fet by to cool. One part of this roaft¬
ed amber, which has loft half of its weight, if the
procefs be properly managed, is then to be mixed with
three parts of linfeed oil. The mixture is to be expofed
to a gentle heat till the amber is drffolved. It is then to
be femoved from the fire, and four parts of the oil of
turpentine are to be added when it is nearly cold*
The clear part, after it has fettled, is ftrained through
a linen cloth. °
This fubftance contains a refinous matter 3489
, . , Benzoin..
combined
24?!
Styrax.
Component combined with an acid, and is commonly ranked among
Parts of balfams. Benzoin is obtained from theflyrax benzoin,
Vegetable1^ tree js a native of Sumatra. It is a brittle
lubftance, has a fragrant odour when rubbed, and,
when it is heated, the acid efcapes. It may be diffolved
in alcohol, but it is infoluble in water.
Styrax.—This fubftance, which is in a half-fluid
ftate, exudes from a tree in Arabia. It is of a green-
ifli colour, has an aromatic tafte, and an agreeable
odour. The benzoic acid, which is one of its com¬
ponent parts, diflblves in wrater. The whole of it is
foluble in alcohol. It abtorbs oxygen, and becomes
harder by expofure to the air.
Storax.—This fubftance is procured from \\\t Jiyrax
officinale, a tree which is a native of the Levant. It
is of a brown colour and brittle, has an aromatic tafte,
fragrant odour, and is foluble in alcohol. It gives out
benzoic acid by heat.
Balfam of Tolu.—This fubftance is obtained from
the toluifera balfamnm, a tree which is a native of
South America. It is of a reddifti-brown colour, be¬
comes folid and brittle when expofed to the air, and
has a very fragrant fmell.
Balfam of Peru.—This is obtained from the myroxilon
peruiferwti, a plant which is a native of South Ame¬
rica. The refin is extrafled by boiling the twigs in
water. It is of the confiftence of honey, has a brown
colour, an agreeable fmell and an acrid tafte. It is fo¬
luble in alcohol. The acid part is foluble in water.
Benzoic acid is driven off by heat.
CHEMISTRY. 733
heated it does not melt, but inflames and burns with Component
2482
Storax.
2583
Ballam of
Tolu.
2484
Of Peru.
2485
Conftitu-
ents.
2486
Properties.
2487
Oiibanum.
XVII. Of Gum-Refins.
1. This clafs offubftances feems to be compofed of a
mixture of refinous matter with a portion of gummy
and extradlive matter. They are never obtained from
plants by means of fpontaneous exudation, but are pro¬
cured by wounding the plants which contain them.
The general properties of gum-refins are the follow'-
ing.
2. They are always in the folid ftate, and common¬
ly brittle and opaque. They are foftened by heat,
but do not melt, and are lefs combuftible than the
refins. They burn with flame. They have an acrid
tafte, with a ftrong fmell, fometimes refembling garlic.
They are partially foluble in water, and in alcohol.
The folution in water is opaque and milky, and the
folution in alcohol is tranfparent. They are partially
foluble in vinegar and wine. They are foluble in
nitric acid, and alfo in the alkalies, with the afliftance
of heat.
3. The gum-refins by diftillation yield a portion of
ammonia, which fhews that azote forms one of their
conftituent parts.
4. Many of the gum-refins have been long known
in medicine, and fome of them are of confiderable im¬
portance. We lhall fpecify the peculiar properties of
the following.
Oiibanum.—This gum-refin is chiefly collected in
Arabia, from the juniperus lycia. It is brought from
Mecca to Cairo, and from thence to Europe, in the
form of tranfparent brittle grains* not lar-ger than a
chefnut, of a yellow colour, a peculiar aromatic fmell,
but with little tafte. With water it forms a milky
fluid, but it is entirely foluble in alcohol. When
2-
an agreeable fmell. It is the frankincenfe of the an- iJfarts
cients, and is ftill employed to diffufe an agreeable . e^e^a es*
fragrance in the Greek and Romifli churches.
Scammony.—This fubftance is extracted from the ScLm4mon
convolvulus fcammonia, a climbing perennial plant
which grows in Syria. By cutting the roots, a milky
juice flows out, which is collefted and dried in the
fun. It is of a dark-gray colour, a bitter acrid tafte,
and a naufeous fmell. It forms a greenifh milky fluid
with water. It is loluble in alcohol. It is employed
in medicine as a cathartic.
Euphorbium.—This fubftance is obtained from the Euphor-
euphorbia officinalis, which is a native of Ethiopia.biuI11,
The milky juice which flows from incifions made in
the plant, is dried in the fun. It is in the form of
fmall yellow tears. It has no fmell, and at firft no
perceptible tafte, but it communicates afterwards a
burning fenfation to the mouth. It is foluble in alco¬
hol. It has been confidered as poifonous. 2490
Affafcetida.—This gum-refin is obtained from the Afiafcetida,
ferula ajfafmtida, a perennial plant, which is a native
of Perfia. It is extracted from the roots by cutting
off the extremity. The milky juice flows out, which
is dried in the fun. It is brought to Europe in large
irregular maffes, which are of a whitilh, reddifti, or
violet hue. It has a ftrong fetid, alliaceous fmell, and
a bitter acrid tafte. It is but partially foluble, both
in alcohol and in water It is much employed in me¬
dicine as a ftimulant and antifpafmodic. 2491
Ammoniac.—This gum-refin is fuppefed to be ob- Ammonia,
tained from another fpecies of the ferula, a plant
which grows in Abyflinia and in the interior parts of
Egypt. It is brought from the Eaft Indies, ufually
in large mafles, which are compofed of little lumps or
tears, of a milky colour. When expofed to the air, it
is changed to a yellow colour. It has a naufeous, fweet
tafte,, which is fucceeded by a bitter. It has a pecu¬
liar fmell. It is not fufible, but when placed on hot
coals, if burns away in flame. It forms a milky folu¬
tion with water and vinegar, and it is partially foluble
in alcohol.
Myrrh.—It is. not yet known from what plant this Myrrl? ''
fubftance is obtained. It is brought from the Eaft
Indies in the form of tears ; is light and brittle, of a
reddiih-yellow' colour, and an undiuous feel. It has a
bitter, aromatic tafte, and a ftrong, but fomewhat
grateful odour. It does not melt, and burns with dif¬
ficulty. It is more foluble in water than in alcohol.
With the former the folution is yellow and opaque j
with the latter it is tranfparent.
Sarcocol.—This fubftance is fuppofed to be the pro-SarcocoL..
duft of the pencea farcocolla. It is brought from Perfia
and Arabia, in the form of fmall whitifti-yellow grains.
It has a bitter and fomewhat fweetifli tafte. It is almoft
entirely foluble in water.
Galbanum.—This fubftance is obtained from
bubon galbanum, a perennial plant which grow's in
Africa. The milky juice fometimes exudes from the
joints of the old plants, but is moft commonly procured
by cutting them acrofs. This juice becomes hard, and
is the galbanum brought to Europe. It is in the form
of whitifh-yellow tears, has a bitterilh acrid tafte, and x
peculiar fmell. It forms a milky folution with water,
wine, and vinegar. It is fcarcely foluble in alcohols
It:
2494
the Galbanum'.
734
Component It does not melt, but yields a
Veg^tab^es ^ diftillation.
C H E M
confiderable proportion
2497
Gamboge.
Sagapenum.—It is only conjectured that this gum
refin is obtained from the ferula perjica. It is brought
Sagapeifum ^ar.?e maffes or diftindt tears from Alexandria. It
is of a yellow colour, becomes hot in the hand, but is
not fufible. It has a hot, naufeous, bitterifii tafte, and
a difagreeable garlic fmell. It is fparingly foluble in
alcohol, but diffolves almoft entirely in water. It yields
2496 by diftillation a fetid volatile oil.
Opoponax. Opoponax.—This gum-refin is obtained from thepaJH-
naca opoponax, a perennial plant which grows wild in
the fouth of Europe. It is obtained by wounding the
flock or root, and is in the form of round drops or
tears, or in irregular maffes of a reddifh-yellow colour.
It has a bitter, acrid, and fomewhat naufeous tafte,
with a ftrong peculiar fmell. It forms a milky fo-
lution with water, and yields an effential oil by dif¬
tillation.
Gamboge.—This gum-refin is obtained from the
Jlalagmitis cambogioides, a tree which grows wild in
Siam and Ceylon. In Siam it is procured in drops by
breaking the leaves and young (hoots, from which it is
fuppofed it derived the name of gum guttae. In Cey¬
lon it is obtained by wounding the bark and colle&ing
thejuice, which is afterwards dried in the fun. It is
brought from the Eaft Indies in cakes or rolls. It is
of a yellow-orange colour, opaque and brittlej has no
fmell, and little tafte, leaving only a flight fenfe of
acrimony when it has been kept in the mouth. It
forms a turbid yellow folution with water, and is al¬
moft entirely foluble in alcohol. It is employed in
medicine, and is a violent cathartic.
Bdellium.—Little is known of this fubftance, or of
the tree from which it is obtained. It is in the form
of fmall pieces or tears of different fizes, of a golden-
yellow colour, with a reddifh tint. This fubftance, or
a fubftance with the fame name, was long celebrated
among the ancient phyficians.
2498
Bdellium.
2499
Prepara¬
tion.
2500
Properties.
2501
Action of
heat.
2502
Compoli-
tion.
XVIII. Of Wood.
1. If a piece of wood be boiled in a great quantity
of water till it no longer gives out tafte or fmell, and
if it be afterwards digefted in alcohol, the fubftance
which remains is the woody fibre.
2. It is either in a fibrous, lamellated, or pulveru¬
lent form. This fubftance, which is more or lefs co¬
loured, has neither tafte nor fmell, is not altered by
expofure to the air, and is infoluble in water and al¬
cohol.
3. When it is heated in contaft with air, it blackens,
exhales denfe, acrid, pungent fumes, and leaves be¬
hind a coaly matter, which does not change its form.
By reducing it to afhes, it is found to contain a little
potafh, fulphate of potafh and lime, and phofphate of
lime. When it is diftilled in a retort it yields water
acetic acid contaminated with oil, a thick oily matter
carbonated hydrogen, and carbonic acid gafes, and a
portion of ammonia, combined with acetic acid.
4. By the aflion of nitric acid on quinquina, which
refembles the woody fibre, Fourcroy obtained from 100
parts, the following products :
Oxalic acid,
Citric acid,
56.250
3-9°5
I S T R Y.
Malic acid, 0.388
Acetic acid, 0.486
Azotic gas, 0.867
Carbonate of lime, 8.330
Component
Parts of
Vegetables.
70.226
Refiduum, 32.031
A quantity of carbonic acid gas was alfo difengaged,
which was not eftimated. The increafe of weight is
afcribed to the oxygen which combined with the bafes
of the acids which were formed during the decompofi-
tion of the woody fibre by the nitric acid. The refi¬
duum, by diftillation, yielded a yellowifh fluid mixed
with alcohol and fome acetic acid, a concrete oil fo¬
luble in alcohol, charcoal, and carbonate of lime, be-
fides carbonic acid and carbonated hydrogen gafes.
The component parts of wmod, therefore, appear to
be, oxygen, carbone, hydrogen, azote, and lime. 2503
1 he relative proportion of wood in plants has been Proportions
eftimated by the proportion of charcoal which theyof charcoal'
afford. From different woods, Prouft obtained char¬
coal in the following proportions.
Black afh, 25
Guaiac, 24
Pine, 20
Green oak, 20
Heart of oak, 19
Wild afh, 17
White afh, 17
XIX. Of Tan.
1. Tan is obtained from a great number of vegeta-pr 250i*
ble fubftances. It exifts in confiderable proportion in tioru^3'*
oak bark and nut-galls j and it is obtained from the
latter by the following procefs.
Reduce a quantity of nut galls to a coarfe powder,
infufe them in water till it is (aturated, pour off the*
liquid, and boil it to drynefs. A black matter re¬
mains, which is tan, nearly in a ftate of purity. It is
propofed alfo to extraft tan from nut-galls by other
proceffes. If a folution of muriate of tin be added to
the infufion of nut-galls, a copious precipitate of a
’yellow colour is produced. When this is feparated
by filtration, and dried, it is in the form of a buff-co¬
loured powder. It is a compound of oxide of tin and
tan. It is then mixed with water, and a ftream of
fulphurated hydrogen gas is paffed through it. An
infoluble fulphuret of tin is formed, and the tan is dif-
folved in water. By filtration and evaporation of this
water to drynefs, a brown fubftance remains, which is
tan } but by this procefs it is not perfectly pure, being
mixed with a portion of extradb've matter. It has alfo
been propofed to feparate tan from the infufion of nut-
galls by means of concentrated fulphuric or muriatic
acid, carbonate of potafh, or lime water.
2. 7 an is a brittle fubftance, of a brown colour, Properties,
has a very aftringent tafle, is foluble in water and al¬
cohol, to both of w’hich it communicates a brown co¬
lour and very aftringent tafte. 25©^
3. W hen it is heated, it becomes black, gives out A<^ion
carbonic acid gas, and burns in the open air, leaving lieat‘
behind a fmall quantity of lime.
4. Tan is precipitated from the infufion of galls, .2f°7
j ° 1 Acids,
s 1 by
Vegetable^,
*5o8
Alkalies.
2509
Earths.
2510
Mf’ta'lic
oxides
and falls.
C H E M
Component by means of fulphuric, nitric, and muriatic acids, and
Parts of fornis wbb them compounds which are foluble in wa¬
ter.
5. The alkalies combine with tan, and form com¬
pounds which are foluble in water. A reddifh brown
colour is produced in the liquid by the addition
of potafh or foda, and it lofes the property of pre¬
cipitating gelatine. Ammonia forms a fimilar com¬
pound with the infufion of galls.
6. Moft of the earths combine with tan, and form
with it compounds which are chiefly infoluble in wa¬
ter. Lime water, added to the infufion of galls, pro¬
duces an olive-coloured precipitate. A fimilar preci¬
pitate is obtained by means of barytes, ftrontites, and
magnefia.
7. The metallic oxides combine with tan, and form
compounds which are nearly infoluble in water. Si¬
milar precipitates are obtained by means of many of
the metallic falls. The green fulphate of iron pro¬
duces no precipitate $ but the red fulphate gives a
deep-blue precipitate, which becomes black by expo-
fure to the air, or when it is dried. This is the bafe
of writing ink, as was formerly defcribed in treating of
the fulphate of iron.
8. Tan forms an infoluble compound with gelatine,
which is the principle of the important procels of
tanning leather, and is nothing more than the combi¬
nation of tan with the animal matter called gelatine or
glue.
9. Tan is chiefly found in the bark of trees ; it is
alfo found in the leaves, the wood, the fap, and fome-
times it is obtained by fpontaneous exudation, as is the
cafe with the fubftance called kino. Several varie¬
ties of tan have been found in different vegetable fub-
ftances, as in catechu, dragon’s blood, fumach, and
fuftic.
10. The quantity of tan varies with the age and fize
of the tree, and at different feafons. The greatefl
proportion has been found in the inner bark. Mr
Davy afcertained the quantity of tan obtained from the
folid matter extra&ed by water, from an ounce of dif¬
ferent vegetable fubftances.
2511
Gelatine.
2512
Exifts in
the bark
chiefly.
2513
Propoition
varies.
Solid Matter. Tart.
* Phil.
‘T-ranf.
IS03.
White inner bark of old oak
young oak
Spanifh chefnut
Leicefter wfillow
Coloured or middle 7 1
bark of joak
Spanifh chefnut
Leicefter willow
Entire bark of oak
Spanifh chefnut
Leicefter willow
elm
common willow
Sicilian fitmach
Malaga fumach
Souchong tea
Green tea
Bombay catechu
Bengal catechu
Nut-galls
108 grs. 72grs.
lit
89
117
43
4T
34
61
53
V
165
156
180
77
63
79'
*9
14
16
29
21
33
13
11
78
79
48
41
261
231
127
I S T R Y. 735
The following proportions of tan were found by ad-Component
ding a folution of glue to the infufion of the plant in Parts ^
water. ^ egetables*
Proportion
of Tan.
Elm
Oak cut in winter
Horfe chefnut
Beech
Willow boughs
Elder
Plum tree
Willow trunk
Sycamore
Birch
Cherry tree
2.1
2.1
2.2
2.4
2.4
3-°
4.0
4.0
4.1
4.1
4.2
Sallow
Mountain afh
Poplar
Hazel
Afh
Spanifh chefnut
Smooth oak
Oak cut in fpring
Leicefter willow
Sumach
Proportion 2314
of Tan. Proportions
in different
plants.
XX. Of Suber.
4.6
4-7
6.0
6-3
6.6
9.0
9.2
9.6
Wz***1*
10,2 Tranf.
1759.
2515
1. The vegetable fubftance denoted by the name ofConft4Lltes
fuber is, according to Fourcroy, the epidermis or outer ^ ef1'
covering of trees. This fubftance is analogous to com¬
mon cork, which is the epidermis of the quercus fubery
from which the name of this peculiar vegetable fub¬
ftance is derived. 4516
2. It is a light, foft, elaftic fubftance, is infoluble in Properties,
water, but readily abforbs this liquid. Common cork
is the fame fubftance, having greater denfity, and ac¬
cumulated in greater quantity.
3. This matter is very combuftible, and burns with AdHon^
a white vivid flame, leaving behind a very black, light, of heat,
voluminous coaly matter. When this matter is diftill-
ed, it yields ammonia.-
4. When cork is treated with nitric acid, carbonic 0f ^ic
acid gas and nitrous gas are evolved. The cork is acid,
decompofed, and converted, partly into a yellow, foft,
umftuous matter, which fwims on the furface, and part¬
ly into fuberic acid j the nature and properties of which
have been already defcribed.
XXL Of Alkalies.
2519
1. The fixed alkalies only have been detefled in Fixed al-
plants, and there are few plants which do not yield a ka'ies only
fmaller or greater proportion of one of thefe alkalies. Itfoun(1*
is fuppofed that they exift in plants, in combination with
acetic and carbonic acids.
2. Potafh, formerly called vegetable alkali, becaufe
it was fuppofed to exift only in vegetables, is found in
all plants except thofe which grow near the fea. The
procefs for extra&iug it has been already defcribed.
The vegetables are reduced to aflies by burning ; the
afhes wafhed with water, which is filtered and evapo¬
rated to drynefs. The potafh remains behind.
3. Shrubby and herbaceous plants yield a greater pro¬
portion of afhes than trees. The branches of trees af¬
ford more afhes than the trunk, and the leaves yield
more than the branches. Other falts are found mixed
with the potafh, fuch as the fulphates of potafh and of
lime, muriate of potafh, phofphate of lime, and phof-
phate of potafh *, the latter of which has been detefted
in maize and wheat. In the following table the pro¬
portion of afhes obtained from 100 parts of different
plants, and the quantity of potafh which thefe afhes
yield, are exhibited.
Sallow,
73$
Component
Parts of
Vegetables.
C H
Alhes.
Sallow,
Elm,
Oak,
Poplar,
Hornbeam,
Beechj
Fir,
Vine branches,
Common nettle,
Common thiftle,
Fern,
Cow thiftle,
Great river rufti,
Feathered rufh,
Stems of Turkey wheat,
Wormwood,
Fumitory,
Red clover,
Vetches,
Beans with their ftalks,
2.8
2.36727
1.351185
1.23476
1.1283
0.58432
o*34i33
3*379
10.67186
4.04265
5.00781
10.5
3*85395
4*33593
8.86
9*744
21.9
E M I S T R Y.
Potafh.
O.285
39. 
0.15343
0.07481
O.I254
O.I4572
0.00000
o*55
2*5033
0-53734
0.6259
1.96603
0.72234
0.50811
I*75
7-3
7*9
0.078
Turkey wheat,
Sun-flower,
Vine branches,
Box,
Willow',
Elm,
Afpen,
Fern,
Wormw'ood,
Fumitory,
7*ri
3*72
2.85
2.674
2*5I5
1.96
1.146
3*221
2.444
14.000
Funcftloits
of Ani¬
mals.
Herbaceous plants, it appears, contain a greater pro¬
portion of earths than trees. In all the kinds of grain
which Bergman examined, he found all the four
earths. From 100 parts of oat grain, Vauquelin ob¬
tained a refiduum of 3.1591, which by analyfis he
found to be compofed of
Silica, 60.7
Phofphate of lime, 39.3
2*75  
2. 100.0
2521
Soda.
4. Soda is generally found in all marine plants, and
in many others which grow near the fliore. The pro¬
portion of foda W'hich many plants containing it yield,
is very confiderable. A hundred parts of the falfola
foda afford 19.921 of allies, from which may be ex-
trafted 1.992 parts of foda. It is from different fpecies
fuci that the foda or kelp of Britain is obtained.
The foda of commerce is extrafted from two fpecies of
falfola, namely the fativa and vermiculata, w'hich grow
abundantly on the fliores of Spain and the Mediter¬
ranean.
By burning the ftem and feeds of the fame grain, the
refiduum by analyfis afforded the following fub-
ftances.
Silica,
Phofphate of lime,
Potafti,
Carbonate of lime,
95
Some traces of oxide of iron were alfo detefted.
55
*5
20
5
XXII. Of Earths.
. *521
k‘me* !• Four of the earths have been detefted in vege¬
tables, namely lime, ,filica, magnefia, and alumina. Few
plants have been found w hich do not contain fome por¬
tion of lime. It is the moft abundant of all the earths
2523 in plants.
Silita. 2. Silica has been found in feveral plants, and chief¬
ly in the epidermis, fome of which are almoft entirely
compofed of this earth. A hundred parts of the epi¬
dermis o£ the following plants yielded the annexed
proportions of this earth.
Bonnet cane, 90
Bamboo, 7X*4
Common reed, 48.1
Stalks of corn, 6.5
2524
.blagneha. 3. Magnefia is more rarely found in vegetables. It
has. been detefted in confiderable proportion in the
fuci and other fea plants. The greateft proportion
yet difeovered is found in the falfola foda. A hundred
3525 parts ^ P^nt have yielded 17.929 of magnefia.
Alumina. ^ 4* Alumina is found in plants in very fmall quan-
5. In the following table are exhibited the quantity
of earths in general, found in ipo parts of different
plants.
XXIII. Of Metals.
Phe only metallic fubftances which have certainly Iron and
been found in plants are iron and manganefe. Iron manganefe.
has been detefted in the aflies of falfola ; and manga¬
nefe has been found in the alhes of the pine, green
oak, calendula,, vine, and fig-tree. Gold, it is faid,
has been found in fome plants, but in very minute pro¬
portion.
Chap. XIX. Of ANIMALS.
Animals conftitute the fecond divifion of orga-rj
nized matter. They are diftinguifhed from vege-ters!^
tables by texture, form, and component parts. The
more charafteriftic differences between animals and ve¬
getables are, the locomotive power of animals, irrita¬
bility, and fenfibility. Animal matters pafs to the
putrid fermentation, and they are all foluble in the al¬
kalies. Sulphuric acid reduces animal fubftances to a
carbonaceous matter. Carbone is precipitated, and
ammonia is difengaged. Nitric acid afts violently on
animal fubftances, with the evolution of azotic gas.
In treating of animal .matters, w’e ftiall firft confider
the funftions of living animals; 2. Their decompofi-
tion ; and, 3. Their component parts. Thefe fubjefts
fliall occupy the three following feftions.
2526
Proportion
eatths.
Oak,
Beech,
Fir,
1.02
*•453
0.003
Sect. I. Of the Functions of Animals.
2529
Cannot be
In taking a view of animal fubftances, it is neceffa-oSlmf
ry to confider the funftions of the living animal, focal prinef-
farples.
mals.
C H E M
Funftmos far at leafl; as tliefe funAions admit of explanation on
of Am- chemical principles. It is beyond the reach of human
j fagacity fully to underftand the fimpleft proceffes in the
animal economy. Thefe cannot be explained on che¬
mical or mechanical principles ; but to comprehend
clearly and fully, even what is known of the func¬
tions of living animals, it would be neceffary to enter
into a defcription of the ftru&ure and nature of the
organs which are employed in thefe fun£tions. But this
is not the province of chemiftry j it belongs to the
fciences of Anatomy and Physiology. We mull
therefore content ourfelves with giving a flrort account
of the chemical changes which take place by the ac¬
tion of living animals. The fun&ions of animals
which have occupied the attention of chemical phyfi-
ologifts, and which we propofe to treat of in this
feftion, are refpiration, digettion, fecretion, and affi-
xnilation.
253°
A vital
ilindtion.
2531
All gafes
not fit for
refpiration
■2532
Not even
pure oxy¬
gen.
2533
3ome fatal
to life.
I. Of Refpiration.
1. Refpiration is to be confidered as one of the vital
functions of animals. No animal can exift when it is
interrupted, nor indeed can it be fufpended, even for
the fhorteft time, without the hazard of life. In the
mechanical part of the fundlion of refpiration, the air
is alternately drawn into the lungs and expelled.
2. It is well known that all gafes are not fit for re¬
fpiration. Some indeed, as the carbonic acid gas, the
■ moment they are inhaled, are deftruftive to life. The
refpiration of others, although they are not produc¬
tive of fuch fudden effefts, yet at laft they prove fa¬
tal to the animal which is forced to refpire them.
Animals are very differently conftituted, both wdth
regard to the ftru&ure of their refpiratory organs,
and with regard to the quantity of air which
muff be refpired in order to fupport life. In thefe
refpe&s the hot and cold blooded animals are very dif¬
ferent from each other j and even among the latter
clafs, namely the cold-blooded animals, there are fome
tribes which require a very fmall quantity of air, and
can bear without much feeming inconvenience a tem¬
porary interruption of this funftion 5 but for all ani¬
mals’, whatever be their nature, whatever be their
Itrufture, or whatever be the modifications of their re-
fpiratory fyftem, the air of the atmofphere is the mod
proper for the fupport of life. It is the oxygen of at-
mofpheric air which is neceffary for the breathing of
animals j but although animals live longer in a given
quantity of oxygen gas than in atmofpheric air, as ap¬
pears from the experiments of Count Morozzo, re¬
lated in the chaper on oxygen gas, yet it is too power¬
ful, or too ftimulating for their organs; for to fuch
as have been confined to breathe it, it has been found
highly injurious.
3. Some of the gafes prove immediately fatal to life;
fuch for inflance is carbonic acid gas. It feems to be
certain that no animal ever made a full infpiration
of this gas, without being deftroyed. Nay, it is fo
noxious to animal life, that the organs themfelves, by
an involuntary a£Hon, obftruft it in its paffage to the
lungs. Other gafes are equally fatal after a few in-
fpirations, fuch as hydrogen and azotic gafes ; and in¬
deed it is probable, if the lungs tvere completely em-
Vql. V. Part II,
I S T R Y. 7J7
ptied of air,, before the infpiration of any gas what- FunAicms
ever, excepting oxygen gas or atmofpheric air, a fingle of ArM-
mfpiration would prove fatal. This, however, is never , inals-
the cafe ; for after the fulled expiration, a confiderable ^ '
quantity of air remains in the lungs. We may con-
clwde, therefore, that the air of the atmofphere alone
is proper for the refpiration of animals, and the fupport
of life.
4. After the fame quantity of atmofpheric air or The
oxygen gas has been once refpired by animals it be-air can on"
comes totally unfit for farther refpiration either by thelybf once
fame animals or any other. It is then not only je_refPired-
prived of the whole ol the oxygen, but is alfo con¬
taminated with noxious gafes. This even happens
to fidies and infers which require a very fmall quan¬
tity of air. If the water in which the former live be
deprived of its air, it is equally fatal to them as being
immerfed under water is to thofe animals which live
in the air of the atmofphere.
5..Attempts have been made by phyfiologids to af-The quart*
certain the quantity of air refpired by animals. This dty.
it will appear at fird fight, mud be extremely differ¬
ent in different claffes of animals. Even in the fame
clafs of animals, it is probable that it varies much.
The difference of the refults of experiments to afeer-
tain this point on man are enormous. No conclufion
whatever can be drawn from the number of refpirations
made in a given time, even if this could be determined
with any degree of accuracy, which is fcarcely to be
expefted. For no funflion of the body is fooner in-
fiuenced by mental affe&ions than the breathing. The
very attention to the circumdance of reckoning the
number of refpirations will have fome effedf in occa-
fioning confiderable deviations from the natural num¬
ber. The number of refpirations which have been
reckoned by fome is 14 in a minute, while others
make the number amount to 27, which fliews that
little dependence can be placed on this mode of cal¬
culating the quantity of the air refpired in a given
time. But even if this could be accurately afeertain-
ed, dill it would not enable us to afeertain the quan¬
tity of air refpired. For it is extremely probable that
this quantity varies greatly in different men and in
different animals, and in the fame animal at different
times, arifing from caufes the effe&s of which either
entirely elude obfervation, or are altogether inappre¬
ciable. And accordingly we find that the differences
of the refults of the quantity of air taken in at a fingle
infpiration, or of the quantity calculated in the lungs
after expiration, are not lefs than thofe of the number of
refpirations. 1
6. The nature of the changes which the air infpired Changes 0*
undergoes has been afeertained with more accuracy,the air*
although the experiments made to determine the
amount of thefe changes vary confiderably. Part of
the air wdnch is refpired difappears ; and it has been
generally fuppofed that it is only the oxygen gas which
is taken up. But according to the experiments of Mr
Davy part of the azotic gas alfo difappears and is ab-
forbed along with the oxygen. Dr Menzies edimates
the quantity of oxygen gas abforbed by a man in 24
hours at rather more than 41 oz. troy. Lavoifier fixes
the quantity confumed by a man in the fame time at
324-oz. nearly; and Mr Davy gives as the refult of
5 A his
73*
CHEMISTRY.
*537
Cafes ex¬
pired.
a538
Water.
Circulation
of the
blood.
Funcft'ons his experiments and calculations about 334oz* oxy'
of -tni- „en ^aS) anj ^i. 0f azotic gas, amounting together to
.about 3 8 oz.
y. The air thrown out of the lungs by expiration
contains a quantity of carbonic acid gas. But here
the refults of experiments to determine the quantity
are as widely different as in other points relating to
refpiration. By one it is reckoned at 15 02. in 24
hours $ by another at not lefs than 37 oz.
8. Water in the frate of vapour is alfo thrown out
of the lungs during refpiration. The quantity efti-
mated by different philofophers exhibits the fame dif¬
ference of refults as in the other fubflances. Accord¬
ing to Hales it is 205- oz. nearly 5 according to La-
voider it amounts to 285-oz.
Component 9. But although it feems difficult or perhaps impof-
parts of the ftble to afcertain with perfeft accuracy the proportions
air expired. or qUantity of each of the fubflances thrown out of
the lungs, yet it is clearly proved by experiment that
the component parts of the air expired are azotic gas,
2540 carbonic acid gas, and water in the flate of vapour.
10. The blood, as it Hows from the left fide of the
heart, is of a bright red colour. It is conveyed by
the arteries to every part of the body. It is then
taken up by the veins, and carried back to the heart, by
means of the venous fyflem. The blood having thus
circulated through the body, enters the right fide of
the heart, and has totally changed its colour. It is
now of a dark purplilh red, inftead of the bright red
colour which it poffeiTed when it palled out of the heart,
to be diftributed through the body. But before the
blood can pafs to the left fide of the heart, again to
enter the circulation, it mufl pafs through the lungs,
where it again acquires the bright red colour. From
the lungs it pafies to the left fide of the heart, from
which it flows as before through the arterial fyflem to
all parts of the body. The blood then acquires this
florid red colour in the lungs. Let us now fee in wdrat
this change confifls.
Changes on II. This change w’as aferibed by fome of the earlier
Are blood, chemical phyfiologifls to the abforption of air. Dr
Prieftley obferved that venous blood, which was ©f a
dark colour, became of a bright red wdien expofed to
oxygen gas, and that hydrogen gas produced a con¬
trary effedl. ..The fame thing has been afeertained
fince, by many other chemifts. According to Dr
Prieftley, the blood was deprived of its phlogifton as it
pafled through the lungs: but according to the theory
of Lavoifier and others, no part of the air infpired is
abforbed ; the blood gives out hydrogen and carbone,
which combining with the oxygen of the air, form
water and carbonic acid. He fuppofed that the quan¬
tity of oxygen in the water and carbonic acid expired
was equal to that which had difappeared during re¬
fpiration. . According to another theory, the oxygen
gas combines with the blood, and while this combina¬
tion takes place, the carbonic acid gas and water
which are expelled from the lungs along with the azo¬
tic gas, are given out. According to later experi¬
ments, it has been afeertained that not only the whole
of the oxygen of atmofpheric air, but part of the
azote, is abforbed during refpiration •, and indeed
fome have fuppofed that the whole of the atmofpheric
air is abforbed by the blood unaltered, and that it is
only after this abforption that the decotnpofition takes Fun<ftiong
place. The whole of the oxygen and part of the of Ani*
azote are retained, and the remaining part of the azote , rn‘lls' .
is thiown out, along with the carbonic acid gas and
water, which are expired ; but this opinion, as well as
moft others with regard to the nature of the changes
that take place during refpiration, refts in a great
meafure on plaufible conjeclure. 2542
1 2. A queftion has arifen among chemifts with re- Are the
gard to the formation of the carbonic acid and the ^ub!lances
water which are expired ; whether it takes place im- i
mediately in the lungs, by the dire£t combination of the blood »
the oxygen of the air with the carbone and hydrogen
of the blood, or whether thefe fubftances previoufly
exifted in the blood in a ftate of combination, and are
thrown out during refpiration. 2542
13. What are the purpofes of thefe changes ? What PurP°fes
are the ufes of refpiration in the animal economy ? A.$relpiratxon.
the blood is the fource from which are derived the ma¬
terials for repairing the conftant wafte of the body,
it is necelfary that means Ihould be provided, to
fupply this wafte, to which the blood is conftantly
fubjepled. This is accompliftred, as we (hall find
afterwards, by the procefs of digeltion, the produft of
which is conveyed to the blood. But before it can
be converted into blood, it muft undergo certain 2544
changes, which take place in the lungs. There isTolormfi.
one effential part of the blood, and an effential partbrma'
alfo of animal bodies, namely the fibrina, which does
not exift in the chyle and lymph, which are the lub-
ftances conveyed to the blood, to repair its wafte, be¬
fore they have paffed through the lungs along with
the blood. Hence it is fuppofed that one purpofe of
refpiration is to form the fibrina of the blood. 2c;45
14. But another great purpofe of refpiration in the To prefery®
animal economy is to preferve the proper degree of tempera-
temperature neceflary for the health and life of the ani-turc‘
mal. It is well known that the temperature of ani¬
mals is not regulated like inorganized matter by the
furrounding medium. In whatever temperature ani¬
mals are placed, except in thofe extreme degrees of
heat or cold which deftroy life altogether, the tempera¬
ture of their bodies continues almoft uniformly the
fame, and. this temperature, it appears, correfponds to
the quantity of air infpired. Hence it is that the
temperature of the lower orders of animals wffich re¬
quire but a fmall proportion of air, as infedfs, fifties, and
amphibious animals, is not much higher than that of
the medium in wftiich they live, and on this account
they conftitute a divifion of animals which have been
diftinguiftied by phyfiologifts by the name oi cold-blooded
animals. The temperature of the w^arm-blooded ani¬
mals, whatever be the temperature in which they live,
is from 96° to 104°. The temperature of roan is
about 98°, while that of birds which require a greater
proportional quantity of air, is ufually 50 or 6° high¬
er. -
15.. The manner in which the temperature of the Thames of
body is kept up by means of refpiration, has been thas animal
accounted for, on the principles of Dr Black’s theory heat«
of latent heat. Part of the latent heat of the air
W'hich was inlpired and combined with the blood, is
given out, and thus raifes the temperature of the blood
and that of the whole body through which it circu¬
lates.
2547
Air abforb-
*d in the
C H E M
Ttvn&ions Jates. But if tills change took place in the lungs, and
all the latent heat of the air infpired was extricated in
that organ, it was urged as an objection to this theory,
that the temperature in them would be much higher
than in other parts of the body. According to the
theory of Lavoifier and Craw’ford, the oxygen gas of
the air infpired combines with the hydrogen and car-
bone which are given out by the blood, forming car¬
bonic acid and water. During this procefs, which
takes place in the lungs, the latent heat of the oxygen
becomes fenfible. Part of it combines with the water
and the carbonic acid, and converts them to the date
of gas; the remainder combines with the blood, to pre-
ferve the temperature of the body. The capacity of
arterial blood for caloric, or the fpecific caloric of ar¬
terial blood, that is, the quantity of caloric which is
neceffary to raife it to a given temperature, is much
greater than that of venous blood. According to
this theory, therefore, the fpecific caloric of arterial
blood, as it circulates through the body, is more and
more diminilhed, till it is at lad converted into ve¬
nous blood. In this way it has been propofed to obvi¬
ate the obje£Hon of the temperature of the lungs be¬
ing highed, if, as it has been fuppofed, the whole of
the caloric is here evolved ; and to account for the
uniformity of temperature which exids in every part
of the body.
16. But if the difference of the fpecific caloric of
arterial and venous blood be not fufficiently great to
ftate oi gas. accoun£ £or pfognomena, this objection has been
attempted to be removed, by fuppofing that the air
is abforbed by the blood in the date of gas, and that
the greated part of the changes which it undergoes, is
effected in the courfe of the circulation. Part of the
caloric, it is fuppofed, is evolved, when the air com¬
bines with the blood, and this portion combining with
the carbonic acid and water thrown off, raifes them to
the date of gas, in which date they are emitted during
refpiration. The air abforbed by the blood gives out
the remaining portion of its caloric in the courfe of the
circulation, when the oxygen combines with the car-
bone and forms carbonic acid, and with the hydrogen
and forms water;, and thus the caloric is gradually
evolved during the courfe of the circulation. Such
then are two of the important purpofes which feem
to be accomplifhed by means of the funftion of refpi¬
ration ; namely, the prefervation of animal tempera¬
ture, and the complete formation of the blood.
II. OfDigedion.
2548 .
-Wafteof 1. The animal body is fubjeft to continual wade,
the body. an(i quantity of this wade varies according to the
nature and age of the animal. This wade is repaired
by the blood, which mud confequently receive feme
fupplies, to make up for its continual confumption. On
this account, all animals require food or nouridiment,
tocompenfate for the wade of the body, and direftly
for the confumption of the blood from which this wade
ar49 is fupplied. .
Foodot dif- 2. Different animals, according to their nature, con-
ferenr ani- dilution, and circumdances in which they are placed,
mals diffe- require different kinds of food. Some animals live en¬
tirely on vegetables, others feed exclufively on animals,
I S T R Y. 739
while a third clafs feed indiferiminately both on vege- Functions
tables and animals. But whatever be the kind of
food, or whatever be the nature of the animal, it is ^ -- Tl 1
all converted, by the procefs of digedion, into the fame
uniform fubdance. In mod animals the food, as it is
taken into the mouth, is broken down, mixed with the
faliva, and conveyed to the domach, and after it has
remained there for a diort time, it is totally changed,
and is converted into the uniform fubdance above al¬
luded to, called chyme. 255*
3. In attempting to account for the fun&ions of the Fa*fe ana"
animal body, chemids and pbyfiologids have been
w'ays too much difpofed to conlider the changes which gifts,
take place within the body, as analogous to thofe which
take place on inorganized or dead matter, in fuppofed
fimilar circumdances. Accordingly we find among
the fpeculations of philofophers, concerning the nature
of the function of digedion, that it has been aferibed
to fermentation. By one fet it was aferibed to one
kind of fermentation, namely to the vinous or acetous;
and by another fet this converfion of the food was fup¬
pofed to be edefted by the putrefactive fermentation.
But now, that the nature and circumdances of the pro-
ceffes of fermentation and digedion have been more
accurately obferved, this opinion, it is probable, is uni-
verfally exploded. The experiments of phyfiologids,
alfo, have led to more rational views concerning this
funCtion. 2551
4. It is now generally admitted, that the converfion Gaftric
of the food into chyme, is effeCted by the aCtion of a pe-J11106,
culiar fluid fecreted In the domach, from which it has
been denominated gqflric juice. This liquid feems to
poffefs different properties in different animals, for
thofe animals which live entirely on vegetables cannot
diged animal food, and the gadric juice of thofe which
have been accudomed to live entirely on animals, has
no effeCt on vegetables. It is true, indeed, that the
nature of animals in this refpeCl;, as well as in mod of
their habits, may be completely reverfed, when it is
effeCfed by flow degrees. All fubdances taken into
the domach are not equally aCted upon by the gadric
juice. Some of the harded are readily diffolved, while
others feemingly lefs compaCt and durable, remain un¬
altered. The hufks of grain in the domachs of many
animals refid its aCtion, while the harded bone is en¬
tirely confirmed.
5. No accurate knowledge has yet been obtained its nature
concerning the nature of the gadric juice. According unknown,
to fome it is of an alkaline nature, and according to
others it poffeffes acid properties. But this difference of
opinion is by no means to be wondered at, if we con-
fider the difficulty, or perhaps the impoffibility of ob¬
taining the gadric juice in a date of purity, to fubjeft
it to chemical examination. Iffit even were poffible to
colled: it perfedly pure, its effeds could not be the
fame as within the body, fince all animal matters, the
moment they are feparated from the living body, be¬
gin to undergo new changes, and therefore mud exhi¬
bit new-properties. All experiments, therefore, which
have been made, to afeertain the nature of the gadric
juice, and the procefs of digedion out of the body,
mud be confrdered as entirely inconclufive. Such ex¬
periments drew us the effeds of this liquid in the date
of dead matter, but can lead to no knowledge of its na-
5 A 2 t«*e
•74o
Fundlions
of Ani¬
mals.
TT 'I53
I ood con¬
verted into
-chyme.
„ ^554
Which is
changed in
to chyle.
^SSS
Chyle fepa.
rates into
two parts.
•2556
Is totally-
changed.
ture ami properties while it exifts in the living bo¬
dy (b).
6. But whatever be the nature of this liquid, or the
procefs of digellion, the food, as we have already ob-
ferved, is broken down in the mouth and mixed with
the faliva, which in the firft inftance, probably contri¬
butes much to favour its commencement j for it has
been obferved that the procefs of digeftion is confider-
ably deranged when the fecretion of faliva is interrupt¬
ed, or its ufual quantity diminifhed. All, then, that is
certainly known concerning this change is, that the
food conveyed to the ftomach is in a very lliort time
converted into the fubftance called chyme.
7. The chyme, which is a foft, pulpy matter, after
•being formed in the ftomach, is carried to the inteftines,
where it is mixed with other fubftances, and undergoes
new changes. As foon as the chyme has palled into
the inteftines, it is converted partly into a milky fluid
called chyle, and partly into excrementitious matter.
Thus it is decompofed by fome procefs, and feparated
into two parts, one of which is deftined for the nourifli-
ment of the body and for repairing its wafte, while the
other is ejected.
8. The chyle, foon after it is formed from the
chyme, mixes with the bile which flows from the liver
into the inteftines. In confequence of this combination,
it is fuppofed the excrementitious matter is feparated
from the chyle, and is thrown out of the body; while the
chyle itfelf is taken up by a fet of veflels called laBeals,
which open on the inner furface of the inteftines, and
receiving the fluid, convey it to a large trunk in which
they all terminate, denominated, from its fituation in
the thorax, the thoracic duEl. The ufe of the bile is
fuppofed to be, to feparate the excrementitious matter
which might prove injurious to the fyftem, if it were
abforbed along with the chyle; and for this purpofe
the bile, it is fuppofed, is decompofed ; one part, namely
its faline and alkaline conftituents, combines with the
chyle, by which it becomes more liquid, while another
part, namely the refinous and albuminous matter, com¬
bines with the excrement, and in this ftate afts as
a ftimulant to the inteftines, fo that the contents w hich
might otherwife prove injurious, if long retained, are
eje&ed.
. 9- As 3 proof that the food which has been taken
into the body has been totally changed, fubftances have
been deteaed in the excrement of different animals
which did not previoufly exift in the food. According
to Vauquehn, excrementitious matter is always diftin-
guilhed by an acid property. Benzoic acid has been
detee.ed m that of horfes and cows. An acid of
a peculiar nature has been found in the dung of pigeons-
but in general this matter is much difpofed to ferment’
wd at laft gives out ammonia.
In the analyfis of the excrement of a hen by Vau-
quelin, compared with the nouriftiment, he found that
tire oats which were taken in were compofed of phof-
CHEMISTRY.
phate of lime and filica, and that the fliells of the egg?, FunfUonj
and the excrements which were examined, confifted of Ani-
phofphate of lime, carbonate of lime, and filica. The , mais-
proportion of filica which w’as found in the excrement v_ J
was lefs than the quantity taken in ; but the quantity
of phofphate of lime was increafed, and a quantity of* Ann, de
carbonate of lime w hich did not previoullv exift in xxix.
the food, wras formed *. " 3-
10. The chyle, it has been obferved, is taken up by prop^t7ies
the la&eals and conveyed to the thoracic duft. Little of chyle,
is known of its properties, excepting that it pofleffes
fome in common with milk. Like it, it coagulates,
and divides into a ferous and oily matter. In the tho¬
racic du6l the chyle is mixed with another fluid called
the lymph, wdiich is conveyed from all parts of the
body by a fet of veffels which have been denominated
lymphatics. This fluid is in confiderable quantity, is of lymph
yifeid and colourlefs, but from the difficulty of colled- 1 ^
ing it, little is knowm of its properties. ’ The lymph
and the chyle, thus mixed togther, are conveyed by the
thoracic dud to the blood veffels. It is mixed with
the blood in the veins, and conveyed by them to the
right fide of the heart, from which it is carried to the
lungs, where it undergoes the changes already deferib-
ed in the account of refpiration, and the whole is con¬
verted into arterial blood, which returns to the heart,
from whence it is diftributed to all parts of the body.
III. Of Secretion.
j-rr1' In n0Urfe °f the cIrcula^on of the blood, Matters fe
different fubftances are feparated from it, fome of parted
which are deftined for the growth and nouriftiment offrom rhe
the body, as in young animals, or for the repair andblood*
lupply of parts that are deftroyed ; while other fub¬
ftances, which feem either to be fuperfluous, or if re¬
tained would be injurious, are thrown out of the bo¬
dy. Thefe fecretions are performed by peculiar or¬
gans, the defeription and operation of which belong
to Anatomy and Physiology. At prefent we fliall
give a ffiort account of two of the moft important of
thefe fecretions, namely, the fecretion of urine, and
that of perfpirable matter.
Secretion of urine.—The urine, which is an ex-*
crementitious matter, is feparated from the blood by 2*
the action of the kidneys. According to the obferva-
tions of anatomifts and phyfiologifts on the ftrufture and
office of thefe organs, a great proportion, or even, as
lome fuppofe, the whole, of the blood pafl'es through
them. As the urine fecieted by thefe organs, feems
to lerve no purpofe in the animal economy, fince the
whole of it is thrown out, it is probable that the fub¬
ftances of which it is compofed, or at leaft their con¬
ftituents, would have proved injurious if they had been
retained.
2. W hatever the. change be which takes place onis
the blood by the aftion of the kidneys, it is of the ut-portant ~
moft importance to the health and even to the life ofchang«r.
the
alfo have this property, from which it has been concLdJd that theVbft pmpTy f coagulating milk. Acids
which produces this efteft entmilk, is of an acid natr 1 - the ^ftance in the ftomach of young animals,
and that it has undoubtedly undergone new change ought tobe recollefted, that it is out of the bodvl
have the property of inducing this change on mill, ’ d befides’lt 15 not known exaaiX what fubftances may
c H E M
Functions the animal; for if thefe organs are deftroyed by dif-
of Ani- cafe or accident, the death of the animal is the certain
^ mals, . confequencc.
3. By the adlion of the kidneys on the blood, new
fubftances make their appearance. Such, for inliance,
are urea and uric acid, which exift in the urine, but
cannot be detected in the blood j but the bales or
conftituents of thefe fubftances muft have formed part
of fome of the matters of the blood, which are there¬
fore decompofed for their evolution ; and this decom-
pofition muft take place in thefe organs. But al¬
though the urine, the fecreted matter, has been accu¬
rately analyzed, and its component parts after it is
throwm out of the body pretty well afcertained, it is
yet unknown what are the peculiar changes which the
256* blood undergoes by the a&ion of the kidneys.
Secretion Perfpiration.—1. A conftderable quantity of matter
from the is feparated from the blood by means of a fet of veffels
flcln- on the Ikin of animals. This aftion is called perfpi-
ration, and the fubftance emitted, perfpirahle matter.
The attention of phyfiologifts and chemifts has been
dire&ed to afcertain the quantity and nature of the
matter thus thrown off. To afcertain the firft point,
many experiments have been made. Sancftorius, an
Italian phyfician, was the_firft who made this attempt,
by weighing himfelf, and eftimating the quantity of
food which wras taken in, and the quantity of excre-
mentitious matter thrown off. The difference, he
fuppofed, indicated the quantity of matter perfpired 5
but neither in his experiments, nor in thofe of many
others, who endeavoured to afcertain the fame thing,
was any eftimate made of the quantity of matter given
2.,j^ out by the lungs.
Quantity. 2. With this diftin&ion in view, a fet of experi¬
ments was inftituted by Lavoifier and Seguin. The
latter was inclofed in a varnilhed bag, which prevent¬
ed the efcape of every thing thrown off from the bo¬
dy, excepting what was loft by refpiration. Having
previoufly weighed himfelf, and having continued the
experiment for fome time, the quantity of matter
thrown off by refpiration was afcertained, by weighing
a fecond time. By weighing himfelf afterwards with¬
out the covering, and repeating the operation at the
end of a fimilar interval, he was thus enabled to afcer¬
tain the quantity loft by tranfpiration from the Ikin,
by fubtra&ing what had been previoufly afcertained
by tranfpiration from the lungs, from the w'hole dimi¬
nution of weight which was indicated in the laft expe¬
riment. From thefe experiments, the following con-
clufions were drawn.
a. In a ftate of health, and when there is no difpofi-
tion to corpulence, the body returns to the fame
weight once every 24 hours.
b. Indigeftion retards tranfpiration. The weight is
increafed for four days, and on the fifth the body re¬
turns to its original weight.
c. Drink only, and not folid food, increafes the
perfpiration. It is lead: at the moment of taking
food, and immediately after.
d. The perfpiration is greateft during digeftion.
e. The greateft quantity of matter perfpired amount¬
ed in a minute to 26.25 grains troy; the leaft to nine
y* grains.
f. The pulmonary tranfpiration is proportionally
greater than that of the Ikin. It is greater in winter,
I S T R Y.
74*
on account of the neceffity of preferving the tempera- Fundlions
ture of the body. of Ani-
_ 3* The quantity of matter perfpired is greateft du- m^5' .
ring hot weather, and in hot climates. The quantity v
too bears a relation to the quantity of urine. The
following are the refults of the experiments of Rye
made in Ireland, on the relative proportion of urine
and perfpirable matter, which were excreted in the
courfe of one day at different feafons of the year.
Matter perfpired. Urine.
Ounces. Ounces.
Winter, 53 42
Spring, 60 40
Summer, 63 37
Autumn, 50 37
4. When the temperature to which the body is ex- Sweat/
pofed is much elevated, the quantity of perfpired mat¬
ter is greatly increafed, and it then appears in a vifi-
ble liquid form called fweat. This anfwers a very im¬
portant purpofe in the animal economy, for by this
means the equilibrium of temperature is preferved.
The heat which is abforbed is carried off along with
the matter which evaporates from the furface of the
body, and thus the increafe of temperature which
would otherwife prove fatal, is prevented. 2
5. The next objeft of chemical phyfiologifts was to Component
afcertain the nature of the fubftance which is perfpir- parts.
ed. This has been found extremely difficult, on ac¬
count of the fmall quantity which it has been poffible
to colleft. But it has been afcertained that it confifts
chiefly of w^ater and carbone, with an oily matter.
Phofphoric acid alfo, and phofphate of lime, have been
detected in the perfpirable matter. In the air which
has been confined in contaft with the fldn, carbonic
acid gas has been detected ; from which it is conclud¬
ed, that either the carbone muft have been evolved,
and combined with the oxygen of the air, or the oxy¬
gen gas muft have been abforbed, and combining with
the carbone, is given out in the ftate of carbonic acid.
The oily matter wdrich is emitted by the fkin, is fup¬
pofed to occafion the peculiar fmell by which animals
are diftinguiffied. The remarkable circumftance of a
dog being able to trace another animal to a great di-
ftance by the fmell, or to difcover his matter by the
fame means to a much greater diftance, is afcnbed
to the emiffion of this matter. The matter perfpired,
according to Berthollet, poffeffes acid properties, and
the acid, he fuppofes, is the phofphoric. Phofphate
of lime has been dete&ed in the fkins of horfes by
Fourcroy and Vauquelin.
Befides thefe, there are other fecretions which are other fe-
deftined for peculiar purpofes in the animal economy, cretions.
or immediately connected with the functions of parti¬
cular organs, or parts of the fyftenr. Such is the fe-
cretion of faliva in the mouth, of tears in the eyes, of
mucus in the nofe, and wax in the ears. The fecre-
tion of milk in the female is deftined for the nouriffi-
ment of the offspring j but we (hall not enter into the
defcription of the organs employed in thefe fecretions.
The nature and properties of the matters fecreted will
come under our confideration in treating of the differ¬
ent parts of animals.
IW.
74-2
, IT un Elions
of Ani¬
mals.
2567
Watte of
the body
CHEMISTRY.
IV. Of Affimilation.
I. The continual wafte and decay of the body re¬
quire to be repaired. This, as we have already feen,
is the purpofe of taking tiourifhment into the body j
part of which being fubjedt to the pi-ocefles of digeftion
mutt be re-an£j refpjratjon^ js converted into blood, from w'hich
^ ’ fource are derived thofe fupplies of new matter which
are wanted in the formation of new parts, or to make
up the general decay of the fyftem. New fupplies of
matter are peculiarly neceffary, in young animals, in
which the parts already formed increafe in fize and
confiftency, and in which, in the progrefs of the growth
of the body, entirely new parts are evolved. But if
there be any thing in the fpeculations of phyfiologifls,
of the whole matter in the body being periodically
changed, even after it has arrived at its full growth,
a conftant fupply of new matter becomes abfolutely ne-
ceflary. All thefe fupplies are furnilhed by the blood,
and for this purpofe it is diftributed to every part of
the body. The materials for repairing the general
wafte, for increafing thofe parts which are already for¬
med, or for the formation of new parts, are all derived
from it. From this fource are derived the moft fluid,
as well as the moft folid parts of the body ; the faliva
of the mouth, and the gaftric juice of the ftomach, fo
neceffary in the fumftion of digeftion, by which the
health and life of the animal are preferved, as well as
the bones and mufcles, which give it ftrength, firmnefs
and motion. The procefs by which the different fub-
ftances which are furniftied by the blood for the repair
of fome parts and the formation of others, has been
diftinguifhed by the name of ajjimilation, becaufe, in
confequence of new actions and combinations, mat¬
ter exadtly fimilar to the parts repaired or renew¬
ed, is depofited, which did not previoufly exift in the
2568 blood- , ,
Sy particu- _ 2- The changes are effe£led by the aftion of pecu-
iar organs, liar organs or veffels. Whatever be the nature of the
food taken into thejftomach, it is converted into chyme
by the procefs of digeftion. This again, by a farther
change, as it paffes into the inteftines, forms the
chyle, which is conveyed to the blood, and afte* this
fluid has undergone the changes which are induced on
it by refpiration, it has acquired thofe properties which'
render it fit for the important purpofes to which it is
deftined.
3. By the aftion of the different fecretory organs,
the fame matter is always feparated from the blood,
while, the animal continues in the healthy ftate. The
perfpirabl.e matter is feparated by the glands or veffels
on the fkin, and the faliva is prepared by the glands
of the mouth. The matter of bones, of mufcles^ or of
nerves, is feparated and depofited in thofe places
where it is required, and no other. In the healthy ftate
of the body, mufcular matter is not depofited among
the bones, nor is offeous matter mixed with the muf¬
cles.
. 4- The moft aftoniflflng part of the animal fyftem
is that power which it poffeffes of accommodating it-
lelf to particular circumftances. It would be lefs fur-
pnfing that the fame a'&ions and the fame fun&ions
after they have commenced, fhould continue to be per¬
formed with uniformity and regularity. But, in the
animal fyftem, new aftions take place, or at leaft thofe
2569
Which al¬
ways fe-
crete the
fame mat¬
ter.
*51°
Functions
vary with
circumftan¬
ces.
which were comparatively feeble and limited, become Cecompoft-
more powerful and more extenfive. Thus, a part oft10n ^Am“
the body which has been deftroyed or removed, is by
this new or extended aclion, completely renovated. A ^ t
large piece of mufcle in the healthy ftate of the body
is foon renewed ; and, what is more furprifing, the con-
ftituent parts of bone are prepared, when neceffary,
and depofited in thofe places where large pieces of this
fubftance have been removed.
5. But although fome, or perhaps all thefe changes Are regu-*
which take place in the different proctffes going on lated by
in the animal fyftem, are of a chemical nature, yet t!T 1'v'n2'
they are fubjefl to the controulof fome pow7er, the cha-^nnc‘^^e’
racteriftics of which are totally different from thofe of
a chemical or mechanical agent. This is the living
principle which counteradls, regulates, and diredfs the
effedls of chemical agents. It is by means of this
power, that the materials of which the different parts
of the body are compofed, are depofited in their pro¬
per places. It is by means of the fame power that a
greater quantity of matter neceffary for the renovation
of any particular part which has been deftroyed, is pre¬
pared and depofited exadlly in that place where it is
■wanted j but the power of this agent is limited. Cer¬
tain fubftances taken into the ftomach, which are unfit
for digeftion or nourilhment, are immediately rejedled $
but others are too powerful, and deftroy the organ it-
felf. As the ftrongeft proof of the exiftence and con-
troul of this power, the ccnftituent parts of animal bo¬
dies begin immediately to decompofe each other as
foon as its adlion has ceafed. The gaftric juice of the
ftomach, which adls only on the fubftances introduced in¬
to it in the living ftate, has been fometimes found to
corrode and deftroy the ftomach itfelf, after death.
But the inveftigation into the nature of this agent, and
of its influence on the animal body, belong to Phy¬
siology.
Sect. II. Of the Decomposition of Animal Sub¬
stances.
1. As foon as an animal has ceafed to live, its frame Dec*ornpofI-
and texture are deftroyed, the conftituent parts are fe-tionof ve-
parated, they enter into new combinations, new fub-?eta,4es
ftances are formed, and the component parts are total-
ly changed. The rapid fpontaneous decompofition ofrent>
animal matters, which has been called putrefaBion, is
one of the moft ftriking charafters by which they are
diftinguilhed. Vegetable matters, w7e have feen, when
vegetation ceafes, are alfo fubjeft to decompofition ;
but in them the procefs is flow and gradual, and many
of the produfls are totally different.
2. The remarkable difference between the fponta¬
neous decompofition of vegetables and animals, de¬
pends on the difference of the conftituent parts of thefe
two claffes of organized fubftances. Animal matters Owing'
are compofed of a greater variety of conftituent princi- ^ diff'e-
ples, and thus originates a greater variety of a£lion,rence
when the different component parts begin to aft on tion.
each other. By the numerous and complicated attrac¬
tions which exift among thefe conftituent principles, de¬
compofition is more readily effefted, and a greater va¬
riety of new produfts make their appearance.
3. But notwithftanding the variety and complicated Conditions
ftrufture of animal fubftances, total decompofition or of putrefac-
putrefaftiontion'
1
*57S
Phenome-
C H E M I
Decompori-putrefaftlon does not take place, except in certain cir-
tm1l^ub”~CUm^anceS.’ ^ the mutual aftion of the confti-
ftances." tuent principles is promoted. The chief circumftances
U...~ v-^, -< neceffary for the putrefadtion of animal matter are,
moifture and moderate heat. Dry animal matters do
not undergo any change. Bones, when moiftened
with water, the foft parts of animals, but efpecially
the liquid parts, run rapidly on to putrefaction. Heat
is alfo neceffary to promote this change. No putrefac¬
tion takes place in animal matters, at or below the
freezing temperature. Before it commences, the tem¬
perature mult be elevated fome degrees above this
point, and as the temperature rifes, the rapidity of the
procefs is proportional. This condition, however, has
its limits j for when the heat reaches a certain point, fo
far from promoting the procefs of putrefaCtion, it is re¬
tarded, or altogether interrupted, by carrying off the
moifture. The contaft of air was thought neceflary
to favour this procefs; but although it appears that this
is not an effential condition, putrefaftion goes on more
rapidly in the open air, perhaps by receiving and car-
rying off the elaftic fluids as they are formed. Mat¬
ters which have already undergone this change, brought
in contaCt with recent animal fubftances, promote and
accelerate putrefaCHon.
4. When animal matters are placed in favourable
circumftances, the folid parts become foft, and the li¬
quid parts become more fluid. The colour changes,
and is converted into a reddifh brown, or deep green.
The odour, which is at firft difagreeable, becomes fetid
and infupportable. An ammoniacal fmell is alfo dif-
fufed, but this is only temporary, while the putrid
odour continues during the whole procefs. The li¬
quids become turbid, the foft parts are melted into a
kind of jelly, accompanied with an inteftine motion,
and an enlargement of the bulk of the w'hole mafs, ow¬
ing to the efcape of elaftic fluids, which are flowly
difengaged. The whole matter is then reduced to
one mafs, the fwelling ceafes, the bulk is diminifhed,
and the colour deepens. Towards the end of the pro¬
cefs, a peculiar odour, fomewhat aromatic, is emitted.
When it ceafes entirely, there remains behind an unc¬
tuous, vifcid, and fetid earthy mafs.
5. The duration of this procefs is extremely vari¬
ous, according to the nature of the fubftances and the
circumft'ances in which they are placed ; but it has
been divided by fome into different ftages. In the
firft: there is merely a tendency to putrefa&ion, ac¬
companied with a very flight change of texture and
colour. The fecond change, or incipient putrefaction,
exhibits fome traces of acidity; the parts are more
foftened, a ferous matter begins to flow from the re¬
laxed fibres ; the colour is more altered, and the pu¬
trid fetid odour is exhaled. In the third or more ad¬
vanced ftage of putrefaftion, the fetid odour is more
or lefs mixed with the fmell of ammonia ; the diflblved
putrid matter becomes of a deeper colour, and is di-
minilhed in weight by the efcape of a great quantity
of volatile matter. In the laft ftage, or wrhen the
procefs is completed, the ammoniacal odour vanifties,
the fetid fmell becomes lefs, and is often fucceeded by
fomething of an aromatic fmell. The animal matter
has diminilhed greatly in bulk, and has loft all ap¬
pearance of organized ftruClure. There remains only
a dark brown, earthy fubftance, unCluous to the feel,
2576
The period
different.
5. T R Y- . 743
which has been caWtA animal earth. But thefe changes Decomi,ofi-
are regulated by the particular circumftances in w hicht,on of Ani-
the procefs takes place. ma^ Sub_
6. In the courfe of the putrefaClive procefs of ani-
mal fubftances, different gafes are fucceffively emitted. 2,577
Thefe are chiefly carbonated, fulphurated, and phof-Elaftic
phorated hydrogen gafes, wmter in the ftate of vapour,flulds
ammonia, and carbonic acid gas. Thefe bodies are
evolved and volatilized, carrying with them fome
of the principal conftituents. Other produ&s, formed
at different periods of the procefs, and of a more fixed
nature, make their appearance ; fuch, for inftance, is
an unftuous matter, and a kind of foap, formed of this
matter and ammonia ; fuch too is nitric acid which is
frequently formed during this decompofition, and is
combined with an earthy or alkaline bale ; and fuch
finally is the unfluous earth which remains after the
evolution and feparation of the former produfts. 2c;^g
7. The procefs of putrefaction, then, confifts inaNatureof
change produced by the aCtion of affinities, morethe ProceI**
powerful than thofe which hold together the conftituent
principles of the animal matter. Thefe conrtituents
are, hydrogen, azote, carbone, and oxygen, with a
certain proportion of fulphur, phofphorus, and dif¬
ferent fpecies of phofphates. During the decompo¬
fition, a portion of the hydrogen combines with azote
to form ammonia, while another portion combines
with part of the oxygen to form water ; part of the
carbone is united with a portion of oxygen, and forms
carbonic acid ; the union of azote with a third portion
of oxygen conftitutes nitric acid ; a combination of
hydrogen, carbone, and azote, yields a volatile or fixed
oil, according to the proportion of the conftituents j
and finally, the faline, earthy, and metallic fubftances,
which are little fufceptible of change, during this pro¬
cefs, remain unaltered, and conftitute the refiduum.
Thus, in taking a general view of the affinities which
come into aClion during this procefs, the amount of
thole which tend to combine the hydrogen with the
azote to form ammonia ; the oxygen with the carbone,
to form carbonic acid ; the carbonic acid with the
ammonia, to form carbonate of ammonia ; the hydrogen,
carbone and oxygen, to form oil, -and this latter with
ammonia to conftitute foap, befide the hydrogen and
oxygen to form water, is greater than the fum of the
forces which retain in combination, the hydrogen, the
azote, the carbone and oxygen, which are the princi¬
pal conftituents of animal compounds.
8. Such are the refults when the procefs is conduced In the opesa
in clofe veffels; but when the procefs takes place inair*
the open air, fimilar refults are obtained, but in a man¬
ner fomewhat different, according to the nature of the
compounds which are formed. In this cafe part of the
animal fubftance is diffolved and carried off by the air
and the water. The ammonia and carbonic acid are
diffipated as they are formed ; part of the carbonated
hydrogen is alfo volatilized by the increafe of tempera¬
ture, and there is no un&uous matter or ammoniacal
foap formed.
9. It is well known that the odour which proceeds Caufe of
from putrid animal matters is extremely offenfive. This ft1? o
is owing in a great meafure, to the fulphurated andciour'
phofphorated hydrogen gafes difengaged ; but it is not
merely offenfive, but noxious to the health, and fome-
times deftru<5live to the life of animals. Thefe effedts
are
744
Component
Parts of
Animal
Subftances.
Chemistry.
2581
Method of
preferving
animal
■matters.
2582
sElements.
are no doubt owing to tbe putrid effluvia which are
exhaled, and which are taken into the lungs during re-
fpiration. To counteraft the effedls of thefe putrid
exhalations, attention fflould be paid to agitate the air
of inhabited places by proper ventilation, which may
be done by burning wood in the vicinity of infedtious
air, fo that the fmoke may be mixed with it, or by
diredling currents of water into fimilar places. To
deftroy the noxious effedfs of putrid miafmata, which
are produced in confined places, frequented by numbers
of people, muriatic acid gas, difengaged from common
fait by means of fulphuric acid, has been fuccefsfully
employed. Oxymuriatic acid gas has alfo been pro-
pofed for the fame purpofe.
10. It is an objedt of confiderable importance in do-
meftic economy, to prevent the procefs of putrefadlion
in thofe animal fubftances which are to be preferved
and employed as food. It is alfo an objedl of fome
importance for many other purpofes. Different me¬
thods have been propofed to accomplifh this. It is
effedled by depriving the animal matters entirely of
their moifture, without wdiich the procefs is interrupt¬
ed. Animal matters are alfo preferved by keeping
them at the freezing temperature, or below it. The
fame objedl is attained by covering up matters to
be preferved with fuch fubftances as readily enter in¬
to combination with water, and thus prevent its effedls
upon the animal matters. The acids, fugar, alcohol,
and fome falts, it is fuppofed, adt in this vvay, by pre¬
venting putrefadlion. With the fame view aromatic
and refinous fubftances, volatile oils, camphor, the
powder of dried aftringent, and fragrant plants, char¬
coal and bitumen, are employed.
.Sect. III. Of the Component Parts of Animal Sub¬
stances.
Having giving a fhort account of the fundlions
of living animals, and of the fpontaneous decompofi-
tion which takes place after death, we now proceed
to take a view of their component parts, as they have
been inveftigated by chemical analyfis. This ftiall be
the fubjedt of the prefent fedtion, which for the fake
of perfpicuity of arrangement, may be fubdivided un¬
der the four following heads: I. Of the conftituent ’
parts of animal fubftances in general. II. Of the li¬
quid parts of animals. III. Of the folid parts; and,
IV. Of fubftances peculiar to different claffes of ani¬
mals.
J. Of the Conftituent Parts of Animal Subftances in
General.
The fimple fubftances which enter into the com-
pofition of the different parts of animals, are chiefly
azote, carbone, hydrogen, and oxygen, of which, ar¬
ranged in different proportions, the foft parts are com-
pofed ; phofphorus and lime, which conftitute the ba¬
fts of the hard parts ; fulphur, the fixed alkalies, mu¬
riatic acid, iion and manganefe. But by the confti¬
tuent parts of animals, is here to be underftood thofe
fubftances into which they are refolved by analyfis.
Some of thefe are compound, and fome are fimple as
will appear from the following enumeration. *
Component
Paits of
Animal
Subftances.
2583
Component
parts.
1. Gelatine,
2. Albumen,
3. Fibrina,
4. Urea,
5. Sugar,
6. Oils,
7. Refins,
8. Phofphorus,
9. Sulphur,
10. Acids,
11. Alkalies, earths, and metals.
I. Of Gelatine.
1. Glue, a well known fubftance in the arts, is gela-Prepara-
tine in a ftate of impurity. This may be obtainedtion*
pure by repeatedly W’aftiing the freftr {kin of an ani¬
mal in cold water, afterwards boiling it, reducing it
to a fmall quantity by flow evaporation, and allowing
it to cool. It then aflumes the form of a folid tremu¬
lous fubftance called jelly. When this fubftance is
dried in the air, it becomes hard and femitranfpa-
rent.
2. Gelatine has different degrees of hardnefs, and Properties,
when pure, it is colourlefs and femitranfparent. It is
brittle, breaks with a vitreous fradlure, and has nei¬
ther tafte nor fmell.
3. When it is expofed to heat, in the dry ftate, it Adlionof
becomes white, then blackens, and is converted into heat.
a coaly matter. Tremulous gelatine melts before it
undergoes thefe changes. When it is diftilled, it af¬
fords a watery fluid, impregnated with ammonia and
a fetid oil. A voluminous mafs of charcoal remains
behind.
4. Gelatine remains unaltered in the dry ftate by Of air an!
expofure to the air j but the folution in w'ater is foonwater-
decompofed, giving out an acid, the nature of which
is unknown, a fetid odour, and fome ammonia. It is
not very foluble in water; it increafes in bulk, and
becomes foft and tremulous. In this ftate it foon dif-
folves in warm water; but as the folution cools, it re¬
turns to its former ftate.
5. With the affiftance of heat gelatine is readily dif-^c;tf5.
folved by the acids. Sulphuric acid a<ffs Howdy on
this fubftance, and forms a brown folution, which be¬
comes gradually darker with the evolution of fulphur-
ous acids. Nitric acid by digeftion on gelatine, is de¬
compofed } azotic gas is evolved, and afterwards a
great quantity of nitrous gas. The gelatine is diffolved
and converted partly into oxalic and malic acids, and
an oily matter which remains on the furface. Muri¬
atic acid readily diffolves gelatine, and forms a browrn-
coloured folution, from which a white pow'der is gra¬
dually precipitated. . When this folution is added to
the folution of tan in water, a copious precipitate is
formed.
6. Gelatine is readily diffolved by the alkalies, with
the aid of heat. There is no adlion between any of the * *ie^*
earths and this fubftance.
7. Some of the metallic oxides form precipitates with ^1^*0
gelatine in its folution in water. The compound thus oxides,
formed is infoluble. Similar precipitates are occafioned
by fome of the metallic falts.
8. Gelatine forms a copious wdiite precipitate with Tan.5*1
tan.
Compofi-
tion.
. 2593
Different
kinds.
C H E M
Component tan. A brittle compound is thus produced, which
An'imaf is ir,ro1uble Jn water> and is n°t changed by expofure
Subftances. to the aJr-
  v   9* component parts of gelatine are carbone, hy-
2592 drogen, azote and oxygen, with fome traces of phof-
phate of lime and of foda, but the proportions of thefe
fubftances have not been determined.
10. 1 here are various kinds of gelatine, probably
ariling from flight variations of the proportions of its
conftituents, or from the addition of other fubftances,
the nature of which has not been diftin£tly afcertained.
Glue is extrafted from different animal fubftances, as
bones, mufcles, membranes, but efpecially from fkins, by
firft fteeping them in lime-water, to purify them from
all extraneous fubftances, and afterwards boiling them
wuth pure water. The ftrongeft glue is obtained from
the fkins of old animals. What is called //sse, is a
weaker kind of glue, which is colourlefs and tranfpa-
rent, and is extraded from the fkins of eels, horfes,
cats, rabbits, and from fome kinds of white leather.
It is this which is employed in the manufadure of pa¬
per, and in gilding and painting. Ifinglafs, another
kind of glue, is extraded from different parts of the
fturgeon, and fome other fifh.
1 r. Gelatine forms a principal part, both of the folid
and fluid parts of animals. It is found in blood and
in milk, in the bones, ligaments, fkin, and other
folid parts.
12. Animal jelly, which is gelatine, is well knowm
as a very nutritious food, and is much employed in
the ftate of glue, fize, and ifinglafs, in numerous
arts.
1 S t R y.
745
no fmeT When dried in a moderate heat, it be-Component
comes brittle and tranfparent, and by being fpread ^arts ot
thm, forms a varnifh. When thus dried, it- is not ■ Animal
changed by expofure to the air, but otherwife it foon
becomes putrid. /
All • 2600
4. Albumen is coagulated by mean’s of the acids. Adlion °f
■With the aid of heat, fulphuric acid diffolves it’heat-
and forms a folution of a green colour. By the adion a c^01
2594
Found in
different
parts of
animals.
2595
Ufes.
2596
Obtained
from eggs
2597
Adtion ef
heat.
2598
Caufe of
coagula¬
tion.
2599 •
Properties
of uncoa-
gu!ated
albumen.
II. Of Albumen.
1. The. white of an egg confifts chiefly of albu-
. men* It is combined with a portion of foda and ful-
phur. from thefe fubftances it cannot be feparated
without decompofition, fo that its properties are pro¬
bably modified by them.
2. When albumen is expofed to a heat of about 165°
it coagulates into a folid white mafs, of different de¬
grees of confiftency, according to the duration of the
heat applied. This is the charaderiftic property of
albumen. In this ftate it has totally changed its pro¬
perties. Formerly foluble in w^ater, it cannot now be
diffolved in that liquid, either hot or cold.
Different opinions have been formed concerning the
nature of this change, or the caufe of the coagulation
of albumen. It has been afcribed by fome to the ab-
forption of caloric, and by others to that of oxygen.
The former opinion was that of Scheele, and the lat¬
ter is fupported by Fourcroy ; but this coagulation is
found to take place when air is entirely excluded, or
without any change being produced on the furround¬
ing air. It has been fuppofed by others, that the coa¬
gulation is produced by the extrication of caloric, as
in other cafes when fluid bodies are converted into
folids. According to an experiment of Fourcroy, this
extrication of caloric adually takes place ; but it is
afcribed by others to a different arrangement of the
particles of the albumen, which is induced by the
adion of the heat applied.
3. The.properties of albumen, it has been obferved,
are very different after coagulation. Before coagula¬
tion it is a glary liquid which has icarcely any tafte, and
Vox.. V. Part II.
of nitric, acid, azotic gas is difengaged : the albumen
is then diffolyed •, nitrous gas is given out, and oxalic
and malic acids are formed, hefides a thick oily fub-
ftance which appears on the furface. The coagula¬
tion of. albumen does not take place when it is dif¬
folved in a great proportion of water. Albumen is
alfo coagulated by means of alcohol and ether, but
if the quantity of water in which it is diffolved be con-
fiderable, the coagulation is not effeded.
5. By trituration with a concentrated folution of Alkalies,
pure potafh, albumen left at reft for fome time, coa-
- gulates, and is converted into a fubftance refemblino-
jelly, which is brittle and tranfparent when it is dried"!
No change takes place on albumen by the adion of
the earths.
6. Albumen is precipitated, from its folution in w’a- Metallic
ter, by many metallic falls. The precipitate is white, faks.
yellow, or brown, according to the metal employed. * 26c
7* Tan precipitates albumen from its folution in Tan. ^
water, in. the form of a copious yellow fubftance,
which is infoluble in water. It becomes brittle when
dry, and is not changed by expofure to the air. 26q.
Coagulated albumen.—Albumen when it is coagu- Properties,
lated, acquires new properties. It is then a tough,
opaque fubftance, of a pearly-white colour, and of a
fweetifh tafte. It is infoluble in water, and is lefs 6
fubjed to change. When it is dried in the tempera- Adion of
ture. of 212 , it is converted into a hard, brittle, yel-heat.
lowilh fubftance, of the tranfparency of horn. When
it is fome time digefted in water, it becomes foft,
white, and opaque, like albumen newly coagulated.
By long adion a fmall part feems to be diflblved, but
no precipitation is formed in this folution by the infu-
fion of tan.
. 8. The mineral acids largely diluted with water, Acids?7
diflolve a portion of coagulated albumen ; but by the
addition of the fame acids in their concentrated ftate,
it is again precipitated.. If coagulated albumen be
kept in diluted nitric acid for feveral weeks, the acid
acquires a yellow colour, which gradually deepens ;
the albumen becomes more opaque, but is not dif¬
folved. By faturating the yellow-coloured acid with
ammonia, no precipitate is formed, but it aflumes a
deep orange colour. If the albumen be then intro¬
duced into liquid ammonia, the latter affumes a deep
orange colour, inclining to red. The albumen dif¬
folves (lowly, and after the folution is completed, it
is of a. yellowifti-brown colour. By wafliing and
boiling in .water, the albumen thus treated with nitric
acid, is diflblved, the liquid becomes of a pale yellow,
and aflumes the form and appearance of jelly, when
it is concentrated. If this mafs be diflblved in boiling
water, the folution is precipitated by tan ; fo that ni¬
tric acid has the property of converting coacrulated al¬
bumen into gelatine.
3. Coagulated albumen is readily diflblved in a fo-Alkalies,
lution of potalh by boiling. Ammonia is difengaged,
5 B and
746
CHEMISTRY.
Component
Farts of
Animal
Subftances.
2609
Compofi-
tion.
2610
Exifts in
different
parts of
animals.
26 it
Ufes.
s6iz
Obtained
from blood.
2613
From muf-
fcie.
2614
Properties.
26:5
Action of
heat.
1616
Acids.
and a foap is formed. If this foap be diffolved in
water, and muriatic or acetic acid be added, a pre¬
cipitate is formed, which alfo has the properties of
foap. When it is moderately heated, a portion of oil
flows out, and a vlfcid brownilh fubftance remains be¬
hind.
4. Albumen is compofed of carbone, hydrogen,
azote, and oxygen, but the proportions have not been
determined. It is fuppofed by fome that it contains a
greater proportion of azote than gelatine.
5'. Albumen conftitutes an eliential part in the com-
pofition of bones and mufcles. Cartilage, horns, and
hair confift almoft entirely of this fubftance, as well as
the membranous portion of {hells and fponge.
6. Albumen is advantageoufly employed for clarify¬
ing liquids. The liquid to be purified is mixed with
the white of eggs, the ferous part of the blood, or
other fubftances containing albumen, and then heated.
By the aftion of heat the albumen is coagulated, and
falls to the bottom, carrying with it thofe fubflances
•which were mixed with the liquid, and occafloned the
opacity, and which, on account of the minutenefs of
the particles, could not be otherwife feparated.
III. OfFibrina.
1. Fibrina is readily obtained by allowing blood to
remain at reft for fome time after it has been drawn
from an animal. The clot, which has formed and falls
to the bottom, is to be feparated, put into a linen cloth,
and repeatedly waflred with water, till the liquid come
off infipid and colourlefs. The fibrous part of the
blood, as it has been called, or the fibrlua, remains be¬
hind. Mr Hatchet obtained it by cutting lean beef
into frhall pieces, macerating in water for fifteen days,
changing the water daily, and fqueezing it out at the
fame time by preffure. The mufcular fubftance was
boiled every day five hours for three weeks in a frefli
portion of fix quarts of water. The fibrous fubftance
was then preffed, and dryed with the heat of a water
bath. What remained is confidered as fibrina nearly
pure.'
2. Fibrina is of a white colour, foft and elaftic,
when it is recently extracled from blood ; and, as it
dries, the colour becomes deeper. When it is extract¬
ed by boiling and maceration from mufcular matter,
it is brittle, has forae degree of tranfparency, and does
not become fo deep in the colour. It has neither tafte
nor fmell. It is infoluble in water and alcohol, and is
not changed by expofure to the air.
3. When it is expofed to heat, it contracts fuddenly,
and emits the fmell of burning feathers. It melts
with an increafe of temperature. It yields by diftilla-
tion, water, carbonate of ammonia, a thick fetid oil,
carbonic acid, and carbonated hydrogen gas, with
fome traces of acetic acid. The coaly matter which
remains behind burns with difficulty, on account of
the phofphate of foda, phofphate and carbonate of lime,
with which it is mixed.
4. Fibrina is foluble in the acids. The folution in
fulphuric acid is of a deep brown colour charcoal is
precipitated, and acetic acid formed. When diluted
nitric acid is added to fibrina, azotic gas is copioufly
difengaged. Fibrina kept by Mr Hatchett for 15 days
in nitric acid diluted with 3 times its, weight of water,
gave to the folution a yellow colour, and it refembled
in its properties the folution of albumen in the fame Component
acid. By this procefs, after being diffolved in boiling ^arts
water, and concentrated by evaporation, the fibrina is
converted into gelatine, which is foluble in hot water, ■ " v_d *1
and is precipitated by tan. The fibriua in this ftate
alfo is isimoft entirely diffolved by ammonia, and the
folution is of van orange colour. Fibrina is diffolved
in boiling nitric acid, in which ammonia produces a
precipitate, compofed chiefly of oxalate of lime. Du¬
ring the aflion of the nitric acid, pruflic acid paffes.
over, with carbonic acid gas and nitrous gas. Oxalic
acid is formed, and a fatty matter appears on the fur-
face. Fibrina is alfo foluble in muriatic acid, with
which it forms a green-coloured jelly. It is diffolved
alfo in acetic, oxalic, tartaric, and citric acids, with
the afliftance of heat j and is converted, by concentra¬
ting the folutions, into a gelatinous mafs. Alkalies
precipitate fibrina from its folution in the acids, in the
form of flakes, which have the properties of gelatine,
and are foluble in hot water.
5. Concentrated potaili or foda, boiled upon fibrina,
forms a deep brown coloured folution, which has the
properties of foap. During the procefs ammonia is
given out.
6. Fibrina is compofed of carbone, hydrogen, a-
zote, and oxygen, but the proportions are unknown.
It is found only in the blood and mufcular parts of
animals.
IV. Of Urea.
/
1. The nature and properties of urea have been
chiefly inveftigated by Fourcroy and Vauquelin. It is
obtained from urine. It may be extra&ed by the fol¬
lowing procefs. ,
If a quantity of human urine which has been paffed Method of
a few hours after taking food, be evaporated with a preparing,
gentle heat, to the confiftence of a thick fyrup, and
allowed to cool, it concretes into a cryflalline mafs.
Add to this mafs in feparate portions four times its
weight of alcohol j with the application of a gentle
heat, great part is difiblved, and what remains confifts
of different faline fubflances. Separate the folution
from the undiffolved part, and introduce it into a re-
■ tort. Diftil with the heat of a fand-bath, and conti¬
nue the boiling till the liquid is reduced to the form
of a thick fyrup. The matter which remains in the
retort cryftallizes as it cools. The cryftals thus form¬
ed are urea.
2. Urea, which is prepared by this procefs, is cry-propertieaC
ftallized in the form of plates, croffing each other.
It is vifeid, refembling thick honey, and of a yellow-
ifli white colour. It has a ftrong acrid tafte, and a
fetid alliaceous fmell. It deliquefees in the air, and
by attradfing moift* re is converted into a thick brown
liquid. It is very foluble in water, and alfo in alco¬
hol. The folution in water concentrated is of a brown
colour. This lolution is gradually decoropofed, air is
emitted, which is partly compofed of ammonia, and
acetic acid is formed in the liquid. If the lolution in
water be boiled, and as the evaporation goes on freftr
portions of water be added, the urea is decompofed j
carbonate of ammonia is difengaged, while acetic acid
is formed and charcoal precipitated. a(jr^
3. By the aftion of heat urea fpon melts, enlarges in Aftion ©f
bulk, and evaporates, emitting an extremely fetid beat-
fmell.
C H E M I
Component fmcll. By diftillation, benzoic acid firft paffes over,
Pam of afterwards caroonate of ammonia, carbonated hydro-
gen gas,-with a fmall portion of pruflic acid and oil.
■ ^ -_/tn C;”, What remains behind confifts of charcoal, muriates of
ammonia and of foda. The benzoic acid, the mu¬
riate of ammonia and the muriate of foda, are confi-
dered as extraneous matter, fo that the products of
urea by diftillation confift of the carbonate of ammo¬
nia, carbonated hydrogen gas, and charcoal. The
component parts of urea,
be
3<>20
Compoli
Cion.
therefore, are luppofed to
Alkalies.
4623
Extraifted
from miik.
Oxygen,
Azote,
Carbone,
Hydrogen,
39-5
32-5
14.7
13-3
100.0
2521
Adlion of
acids.
4. If one-fourth of its weight of diluted fulphuric
acid be added to the folution of urea, and heat be ap¬
plied, an oily matter appears on the furface, which
concretes on cooling. Acetic acid is found in the li¬
quid which is colledted in the receiver, and fulphate
of ammonia remains in the retort. The whole of the
urea may be converted into acetic acid and ammonia
by repeated diftillation.
Nitric acid produces a violent effervefcence with
the cryftals of urea. The liquid becomes dark red,
and during the effervefcence nitrous gas, azotic gas,
and carbonic acid gas are evolved. A concrete white
matter remains after the effervefcence has ceafed, mix¬
ed with a fmall portion of the red liquid. The refi-
duum produces a detonation with the application of
heat.
Urea is foluble in muriatic acid, but it remains un¬
changed. A diluted folution of urea abforbs very ra¬
pidly oxymuriatic acid gas. Whitifti flakes appear,
which foon become brown, and adhere to the fides of
the veflll. After the abforption, the folution gives out
carbonic acid and azotic gafes. Muriate and carbo¬
nate of ammonia remain in the liquid after the effer¬
vefcence ceafes.
5. Urea is readily diffolved in folutions of potafh or
foda. Ammonia is alfo difengaged, when urea is dif¬
folved iu folutions of barytes, lime, or magnefia. It
is alfo difengaged by triturating pure potalh in the fo-
lid ftate with urea. Heat is produced at the fame
time. The mixture affumes a brown colour, and an
oily matter is depofited.
Muriate of foda diffolved in a folution of urea in
water, affords by evaporation cryftals in the form of
regular odftahedrons; but muriate of ammonia dif¬
folved in the fame way, cryftallizes in the form of
cubes.
V. Of Sugar.
i. Sugar has only been difeovered among animal
matters in milk and in the urine of perfons labouring
under diabetes. Sugar is obtained from milk by eva¬
porating freih whey to the confiftence of honey. When
it cools, it concretes into a folid mafs. This is to be
diffolved in water, and being previoufly clarified with
the wftrite of eggs, to be filtered and evaporated to the
confiftence of fyrup. Cryftals of fugar of milk are de¬
pofited on cooling.
s t r y. 747
2. When fugar of milk is pure, it is of a white Component
colour, has a fweetiftr tafte, but no fmell. It cryftal- Par.tsof
lizes in the form of regular parallelepipeds, terminating
in four-fided pyramids. The cryftals are femitranfpa- ^ces-
rent. The fpecific gravity is 1.543. It is foluble in 2624
feven times its weight of water. " Properties.
3. When it is burnt, it exhibits the fame appearances A^o^of
as vegetable fugar, giving out at the fame time the heat.°n °
odour of caromel. Similar produtfts are obtained by
diftillation as from vegetable fugar ; but the empyreu-
matic oil has the odour of benzoic acid. rSii
4. By means of nitric acid the fugar of milk is partly Acids,
converted into facla&ic acid. 2527
Sugar from diabetic urine.—This is obtained by eva- Method of
porating the urine of perfons labouring under diabetes. obtaftur,g
One twelfth of the weight of urine of a fweet iafted fub-1!:‘
fiance of the confiftence of honey has been obtained by
this procefs. WTien this fubftance is treated with ni¬
tric acid, it affords oxalic acid in the fame proportion
as vegetable lugar, but no facla£lic acid is formed, as
when fugar of milk is treated in the fame w'ay. It has
not been cryftallized.
VI. Of Oils.
262s
1. The oils which have been detefted in animalsIn difler-
have the charafters of fixed oils. Sometimes they ex-ent ft3165*
iff in the folid ftate, and fometimes they are liquid.
Fat is a copious animal produftion, which has different
degrees of confiftence, as it is obtained from different
animals. To purify it, it is cut into fmall pieces,
which are to be well walhed with water, and the mem¬
branous and vafcular parts feparated. It is then put
into a ftiallow veffel along with fome water, and kept
melted till the whole of the water is evaporated. It
is then of a pure white colour, without tafte or
fmell. 262$
2. It melts at different temperatures. Hogs lard re-A<£lionof
quires only a temperature 0197°, while the fat extraft-*16^*
ed from meat by boiling requires a temperature of
127°. When the heat is raifed to 400°, a white fmoke
is given out j as the heat increafes it is decompofed,
and becomes black. When hogs lard is diftilled in a
retort, carbonated hydrogen and carbonic acid gafes,
accompanied with a very offenfive ftnell, pafs over. A
portion of water is alfo obtained, and a white oil which
concretes in the receiver. Acetic acid and a portion
of febacic acid are alfo found in the receiver,
mafs remains behind in the retort.
3. Fat is infoluble in water and alcohol,
folved and decompofed by the ftrong acids,
acid be poured upon fat, and a moderate heat applied,
the acid is decompofed, and the fat is converted into a
yellow coloured ointment. Fourcroy calls this an oxide
of fat ; the oxygen of the acid having combined with
the oily matter. 2(j3it
4. Fat combines with the alkalies in the fame way as Alkalies,
other oily fubftances, and with them it forms foap.
5. The conftituent parts of fat, as appears from theCompofi»
produfts which are obtained from its decompofition, aretion*
oxygen, hydrogen, and carbone.
There are befides fome other oily fubftances obtain¬
ed from different parts of animals, as fpermaceti from
the head of the fpermaceti-whale, fpermaceti-oil, which
is feparated in the purification of the fpermaceti, and
5 B 2 train
A black
263a
It is dif- Acids.
If nitric
748
Component train oil, extra^led from the
Pm ts of ancj from other fea animals.
Animal
Subftances. VIJi Qf Refins.
G H E M
blubber of the whale,
1. Refinous fubftances are found in different parts of
animals, or rather they exift in thofe fubftances which
are fecreted by animals.
2. A refinous fubftance is extrafted from the bile of
animals. It is extracted from the frelh bile of the ox,
by muriatic acid, in the proportion of one part of the
latter to 32 of the former. The mixture remains for
fome hours, is filtered, and a white coagulated fub¬
ftance is feparated. The filtered liquid, which has a
fine green colour, is to be evaporated in a glafs veffel
with a gentle heat. The evaporation is continued till
a green-coloured fubftance precipitates, which is to be
feparated, and waflied with pure water. This fubftance
2633 is the re-fm °fhlle'
Properties. 3* ^ *s a dark-brown colour, but when fpread
thin, is of a fine green. The tafte is extremely bit-
26"4 ter*
Action of 4. When it is heated to the temperature of 1220
heat. it melts. By increafing the heat, it takes fire and burns.
It is foluble in cold and hot water and alio in alcohol j
but it is precipitated from the latter by water. The al¬
kalies alfo diffolve this fubftance, and form a compound
which, has the properties of foap. This fubftance is
precipitated from all thefe folutions by means of di¬
luted acids.
A refinous fubftance has alfo been difcovered in hu¬
man urine, in ambergris, which will be afterwards de-
fcribed, and in caftor, civet, and mulk.
^ VIII. Of Phofphorus.
Given out During the putrefaction of animal matters, phofpho-
trefXom rUS is §iven ?Ut in the ftate of phofphorated hydrogen
gas, fo that it muft have entered as a conftituent into
thefe matters.
IX. Of Sulphur.
2636
Found in Albumen is always mixed with a portion of fulphur.
albumen. It has been dete&ed in the white of eggs and in milk,
in the blood, in the urine and faeces, in the mufcles
and in the hair. According to Prouft fulphur exifts
m the blood, in combination with ammonia, forming
a hydrofulphuret of ammonia.
2637
Enumera¬
tion of
acids.
X. Of Acids.
No lefs than 12 different acids have been deteded
ready formed in animal bodies. Thefe are,
Sulphuric, Malic,
Muriatic, Benzoic,
Phofphoric, Tadic,
Carbonic, Uric,
Acetic, Rofacic,
Oxalic, Amniotic.
1. Sulphuric acid has been found combined with
loda, forming fulphate of foda, in the liquor of the
amnios of cows. Sulphate of lime has been deteded
in the urine of quadrupeds.
. 1 2' Muriatic acid exifts in combination with foda
fodalra°ft ^ thC animal ^luidS, formin§ muriate of
I S T R Y.
3. Phofphoric acid is found in great abundance in Component
different parts of animals. The phofphate of lime 1>arts °f
conftitutes the bafis of the bones, and it exifts alfo in Animal
almoft all the folid parts of animals, and in moft nfSllhftances‘<
the fluids. In the blood it is combined wuth iron.
4. Carbonic acid is found combined with lime in the
urine ofhorfes and cows. It has alfo been deteded in
frelh human urine.
5. Acetic acid is found in urine ; but it has been
deteded in great abundance in the red ant, and was
formerly called formic acid, at leaft combined with
malic acid.
6. Oxalic acid has been found in urinary calculi.
7. Malic acid lias been found in the liquid obtained
from the red ant. This is obtained by bruifing the
ants, and macerating them in alcohol. The alcohol
is driven off by diftillation, and an acid liquid remains
behind. By faturating this liquid with lime, and add¬
ing acetate of lead to the folution, a copious precipitate
is formed, which is foluble in acetic acid, fo that this
liquid contains fomething befides acetic acid. If nitrate
of lead be mixed with the acid liquid after it is faturated
with lime, a precipitate is formed, which is the malic
acid combined with lead.
8. Benzoic acid has been detedled in human urine,
and in confiderable quantity in the urine of cows. It
has been found in the blood, white of eggs, in glue,
filk, or wool, in the fponge, and in mulhrooms.
9. La£tic acid is obtained from milk, when it be¬
comes four. It is alfo faid, that it has been found in
new milk.
10. Uric acid exifts in human urine, and forms
one of the conftituents of urinary calculi. One fpe-
cies of calculus, indeed, is compofed entirely of this
fubftance.
11. Rofacic acid is obtained from the urine of
perlons labouring under fevers and other dilorders,
when the urine depofits what is called a laieritious fe~
diment.
12. Amniotic acid is obtained from the liquid of
the amnios of the cow.
XI. Of Alkalies, Earths, and Metals.
, I. The different alkalies have been found in animal Alkidies.
fluids. Potafh has been found in confiderable abun¬
dance in the urine of quadrupeds. It has alfo been
detedfted in the milk of cows. Soda is found in all
the fluids. It is ufually mixed with albumen. It is
frequently combined with the phofphoric and muri¬
atic acids. Ammonia alfo has been detedled in
urine. .
2. I be eartiis which have been dete&ed in animals Earths,
are, lime, magnefia, and filica. Lime forms, in combi¬
nation with phofphoric acid, the bafis of bones. It is al¬
fo found in the fame ftate in the other folid parts, as
well as in moft of the fluids. The (hells of animals are
compofed chiefly of carbonate of lime. Magnefia has
been found in human urine, combined with phofphoric
acid and ammonia. It forms alio one of the compon¬
ent parts of urinary calculi. Silica has only been found
in fimilar concretions.
3. The only metal which has been dete&ed in ani-Metals0
mals is iron, in combination with phofphoric acid
which forms a conftituent part of the blood.
II. Fluid
C H E M
II. Fluid Parts of Animals.
Component
Parts of
Subftances ^"e treat t^ie an^ma^ fluids in the following
i   - order ;
Enumera- f • Blood,
tion. 2. Bile,
3. Urine,
4. Milk,
5. Saliva,
6. Tears and mucus of the
nofe,
7. Humours of the eye,
8. Wax of the ear,
9. Synovia,
10. Semen,
11. Liquor of the amnios,
12. Fluids fecreted by dif-
eafe.
264a
Properties.
2643
Separates
into two
parts.
2644
Adh'on of
acids.
2645
Alkalies.
2646
Metallic
oxides.
2647
Vegetable
produc¬
tions.
2648
Serum.
I. Of the Blood.
1. The blood is a fluid of a red colour, which circu¬
lates through the body, and is diflributed by means
of the arteries to every part of it, communicating,
as we have feen, heat and nourifhment. It is then re¬
conveyed by the veins from the extremities to the
heart. Human blood, and that of fome other animals,
is of a fine, purplifh-red colour, has fome degree of con-
fiftency, foft and foapy to the feel, of a fweetifh faline
tafte, and a peculiar odour. The blood is found to
vary in confiftence, fo that its fpecific gravity alfo va¬
ries from 1.053 to i-I26-
2. When blood, after it has been feparated from the
body, remains for fome time at reft, it feparates into
two parts. One part called the c/o( or cruorr is coagu¬
lated, and continues of a red colour ; the other part,
called the ferum, remains fluid. The ufual proportion
of cruor to ferum, is about one part of the former to
three of the latter. This proportion, however, is fub-
je£t to confiderable variation.
3. The acids alfo coagulate blood, and decom-
pofe it. Concentrated fulphuric acid occafions a brown
colour, with the prodmfftion of charcoal. It is coagu¬
lated by nitric acid, with the evolution of azotic gas,
and the production of carbonic and oxalic acids, be-
fides fome undtuous matter. Muriatic acid alfo coagu¬
lates blood, but wuthout any perceptible change of co*.
lour. Oxymuriatic acid renders it as black as ink.
Acetic acid alfo produces a coagulation.
4. The cauftic alkalies dilfolve the coagulum of blood,
even wdien it has been produced by acids. If they
are mixed with blood recently drawn, the coagulation is
interrupted. Many faline bodies produce a fimilar
effedt by preventing coagulation, or decompofition.
5. The metallic oxides have little perceptible ac¬
tion on blood, except thofe which readily part with
their oxygen. It is then coagulated. Almoft all me¬
tallic foluthms coagulate blood, and have the pro¬
perty, as well as the alkaline lalts, of preferving it from
putrefadlion.
6. Many vegetable fubftances when mixed with
blood, prevent its putrefadlion, fuch as fugar, volatile
oils, camphor, refins. It is coagulated by folutions of
gum and of ftarch. Tan produces a copious precipi¬
tate in blood, and gallic acid gives a black co¬
lour, owing to the iron which is contained in blood.
The latter precipitate may be obtained by diluting the
blood with a confiderable proportion of water.
7. Blood, by remaining at reft, it has been ob-
ferved, feparates into two parts, the ferum and the
cruor. The ferum is of a pale, greenifh, yellow co¬
lour, of a thinner confiftence than blood ) but retains
1 s t r y. 749
its tafte, fmell, and foapy feel. The fpecific gravity Component
is about 1.0287* confequence of its containing a ^>alts°f
portion of loda, it gives a green colour to fyrup °fSubftances
violets. Serum coagulates at the temperature of 156°. ^»
The fame effeft is produced by adding boiling water.
This coagulum is of a grayiih white colour, refem-
bling the white of eggs. By breaking the coagulum
to pieces, a fluid may be expreffed from it, which has
been called the fernjity of blood. The refiduum be¬
ing wafhed with boiling water, exhibits the proper¬
ties of albumen.
8. By diluting ferum with fix times its weight of Gelatine,
water, and boiling it, the albumen is coagulated. If
the remaining liquid be evaporated with a gentle heat,
till it is confiderably concentrated, it aflumes the
form of jelly, and this poffefles the properties of ge-
latine* . . 2*50-
9. By heating the coagulated fetum in a filver vef-Sulphur,
fel, the filver is blackened, in confequence of its con-
verfion into a fulphuret, by combining with fulphur
contained in the coagulum. It has been already %
mentioned, that this fulphur exifts in the blood, in
combination with ammonia, in the ftate of hydroful-
phuret- . . 2^r
10. The fe rum of blood contains muriate of fo-Different
da, carbonate of foda, phofphate of foda, and phof-ftftts*
phate of lime. Thefe falls may be obtained by mix¬
ing ferum with double its weight of w'ater, applying
heat to coagulate the albumen, which being Separat¬
ed, and the remaining liquid filtered and evaporated,
cryftals are depofited on cooling. The foda exifts
in blood combined with gelatine and albumen, and
is in its cauftic ftate. It unites wdth the carbonic 2(J
acid of the air during the evaporation. The compo- Compofi-
nent parts of ferum, therefore, are the following. tion of fe-
Albumen, rUm'
Gelatine,
Hydrofulphuret of ammonia.
Soda,
Muriate of foda,
Phofphate of foda,
Phofphate of lime.-
2 3"
11. The cruor or clot of the blood, the other por-^ruor-
tion into which it fpontaneoufiy feparates, is of a red
colour, and has confiderable confiftence. Its fpecific
gravity is about 1.245. By walking this fubftance
with a fmall quantity of water, and continuing the
procefs till the water pafles off colourlefs, part of it is
diffolved by the water, and part remains in the ftate
of a folid white elaftic fubftance, wThich is the fibrina
of the blood. That part which is held in folution by
the water contains the colouring matter. This folu¬
tion converts the fyrup of violets to a green colour.
By expofure to the air it depofits albumen in the form
of flakes. By the evaporation of this folution to dry-
nefs, and the addition of alcohol, part is diffolved.
If this folution be evaporated, the refiduum converts Albumen
vegetable blues to green, and mixes wdth water like and foda.
foap. This refiduum contains albumen and foda. 2655
12. If the watery folution be evaporated to drynefs Iron.
writh a moderate heat, a quantity of iron remains be¬
hind, which may be feparated by the magnet. It has
been faid that the quantity of iron in the blood of a
healthy man amounts to more than two ounces j but
1 this
750
t'omponent
Parts of
Animal
Subftances.
2656
Quantity
conjec¬
tured.
CHEMISTRY.
i«S7
Fibrin a.
a<?j8
X)iftillation
2659
Aftion of
heat.
tms is little better than conjefture, founded on vague
calculation. The iron in blood is combined with
phofphoric acid. If the watery folution be evaporat¬
ed to drynefs, and the refiduum obtained, be calcined
in a crucible, a red mafs remains, which amounts to
0.0045 of the blood which was employed. Part of
this reliduum, which is phofphate of iron, is diffolved
by digeltion in nitric acid. From this it is precipi¬
tated of a white colour, by ammonia. With the ad¬
dition of pure potafh, the precipitate becomes red.
By adding lime water to the folution which contains
the potafh, a precipitate is formed, which is phof¬
phate of lime. By the aflion of thefe re-agents, it
appears that the iron in the blood combined with
phofphoric acid, is in the date of fub-phofphate. Phof¬
phate of iron is infoluble in water, but foluble in the
acids. It is partially decompofed by the alkalies,
which carry off part of its acid, and leave the remain¬
der with excels of iron. Thus it is that this fait is
preferved in the date of fub-phofphate, by means of the
foda which exids in the blood.
13. 'I'he method of obtaining fibrina from blood
has been already defcribed. This fubdance may be
feparated by agitating, or dirring rapidly with a dick,
the blood which has been newly drawn from the ani¬
mal. The fibrina or fibrous matter being well wadied
and dried on paper, lofes about two-fifths of its weight,
and becomes hard and brittle. The mean proportion
of fibrina in the blood of man has been edimated at
0.0028. The fibrina is formed in the blood as it
pafies through the lungs, and is depofited in the muf-
cular parts of animal bodies, of which it forms one
of the principal condituents. When the fibrina is
feparated from the blood, the latter is no longer
difpofed to coagulate when it is left at red. A
dakey matter only is feparated, which appears on the
Ilirface.
14. Blood dried with a moderate heat, exhales a
quantity of water which poffefles a peculiar odour,
owing to a portion of animal matter which it holds in
folution. If the blood thus dried be didilled in a re¬
tort, a watery duid pafles over, afterwards carbonic
acid gas, carbonate of ammonia, which cryftallizes in
the neck of the retort, a duid oil, carbonated hydro¬
gen gas, and an oily matter of the confidence of but¬
ter. A green powder is precipitated from fulphate of
iron by the watery fiuid. A portion pf this powder is
foluble in muriatic acid, and a fmall quantity of Pruf-
fian blue remains behind, from which it appears that
prudic acid and an alkali are contained in the watery
liquor. J
A quantity of dried blood amounting t0 92i6grs.
was introduced into a large crucible, and being gra¬
dually heated, it became at fird nearly fluid ; it then
dwelled up, gave out abundance of yellowidi-co-
1 oil red jetid fumes, and at lad took fire, and burnt
with a white dame. The dame and the fumes ceafing
to be emitted, were fucceeded by a light, acrid
fmoke, which had the odour of pruffic acid. When
the matter had been deprived of about five-fixths of
its weight, at the end of fix hours it melted again ; a
purple dame appeared on the furface, with the evo¬
lution of denfe acrid fumes, which being colledled
were found to poflefs the properties of phofphoric
acid. One hundred and eighty-one grains of a deep
black colour and metallic brilliancy condituted the Component
refiduum. It was attra&ed by the magnet. From thefe **arts
obfervations it appears that the conftituent parts of the c
^ on Dttances.
blood are the lollowing. l   ^
. 4660
o- boda. Compoii-
7. Subphofphate of iron. tion.
8. Muriate of foda.
9. Phofphate of foda.
10. Phofphate of lime.
1J. Benzoic acid.
Water.
Fibrina.
Albumen.
Gelatine.
5. Hydrofulphuret of am¬
monia.
15. The conftituent parts of blood vary
derably at different periods of life, and in different
ftates of the body. The colouring matter of the blood &c!°
of the foe us has been found to be darker and more
copious. It contains no fibrina or phofphoric acid. 2662
16. The blood of perfons labouring under inflam-
matory diforders feems to poffels different propertiestory'
from that of perfons in health. It then exhibits, foon
after it is drawm from the body, what has been called
by phyficians the bvjfy coat, which is confidered to be
the chara&eriftic of inflammation. This inflammatory
cruft has been found to confift of fibrina, fo that the
cruot deprived of this matter, becomes foft, and is al-
moft entirely foluble in w^ater. The albumen of the
ferous part has alfo undergone fome change. It af-
fumes a milky appearance when mixed with hot wa¬
ter, and does not coagulate when it is heated.
17- I he ferum of the blood of perfons labouring Diabetic,
under diabetes, is deprived of its faline tafte, has the
appearance of whey, ,and fomew'hat of a faccharinc
tafte.
confi-
2661
Vanes at
II. Of Bile.
1. Bile is an important fluid in the animal economy, importance
It feems to perform an effential part in the funaion and pro¬
of digeftion. It is fecreted from the liver, and is ofPerties*
a yellowulh-green colour, has a foapy feel, a bitter
tafte, and a peculiar odour; but it varies in colour,
and in fome other of its properties, in different animals.
It varies alfo in its fpecific gravity. It has been efti-
mated at 1.0246. The experiments which have been
made on bile relate chiefly to that obtained from the
gall-bladder of the ox, hence denominated ox gall,
Whfen bile is ftrongly agitated, it forms a lather like
foap, and hence it has been called an animalfoap. It
mixes in all proportions with water, to which it com¬
municates a yellow colour.
2. When bile is expofed to a moderate heat, it be- Atfion of
comes thick, having loft a great part of its weight, heat.
I he vapour it exhales has a peculiar offenfive odour.
A lolid brown mafs is thus obtained, which has a bit¬
ter, with lomewhat of a Iweetifh tafte, becomes foft
with the heat of the hands, is dudlile, attrafts moifture
from the air, and is foluble in water. This fubftance
effervefees flightly with acids, and acquires a perceptible
odour of mulk or amber, when kept for fome time.
This has been called the extracl of bile. When
this procefs is conducted in clofe veflels, with the heat
of a water bath, it gives out a clear aqueous fluid of a
difagreeable odour, which undergoes no particular
change by means of re-agents, if the diftillation has not
been carried too far, or the bile has not become in fome
degree putrid. If this latter, circumftance has taken
place,
C H E M
Component place, tTie watery produft lias frequently a ftrong odour
F . of mufk, and becomes turbid on cooling.
Animal^ W|ien extract of bile is heated in a retort, it is
. ii i. ance . (jecomp0{'e(j wjt}1 peculiar appearances. When heat is
a666 gradually applied, a watery fluid, which is flightly
Diftillation. nmddy, and of a fetid odour, paffes over. This fluid
precipitates metallic falts, and contains almoft always
fulphurated hydrogen. The matter in the retort en¬
larges in volume, and the fluid which then comes over
is of a brown colour, extremely fetid, and contains car¬
bonate and zoonate of ammonia. Soon after an oil is
evolved, which is at firft liquid, and afterwards becomes
- of a brownifh colour, thick and empyreumatic, and of
a moft offenfive fetid odour. At the fame time car¬
bonate of ammonia cryftallizes on the fides of the re¬
ceiver. There is then a copious evolution of an elaftic
fluid, compofed of carbonic acid, carbonated and ful¬
phurated hydrogen gafes, holding in folution a fmall
portion of oil. The carbonate of ammonia thus obtain¬
ed, does not amount to the one-eighth part of the quan¬
tity which is extradled from the blood and from the
bones of animals, from which it is fuppofed that the
bile is lefs animalized than many other animal fub-
ftances. There remains behind a black fpongy mafs
of coal, which is eafily burnt. This coaly matter, by
expofure to the air, efflorefees on the furface, which is
found to be carbonate of foda. When it is well burnt,
it preferves a deep gray colour, and there is feparated,
by means of cold water, nearly half its weight of carbo¬
nate of foda, a little muriate of foda, phofphate of foda,
4667 phofphate of lime, with fame traces of iron.
Adtion of 3. Bile is deco upofed by all the acids. A precipi-
adds. tate is formed, which is always of a green colour. Part
of this precipitate remains fufpended in the folution,
and is even diflblved by agitation. I he folution being
filtered, leaves on the filter a portion of coagulated al¬
bumen. By evaporation the liquid depoilts a deep
green flaky fubftance like pitch, which has confider-
able tenacity, fwells up when put upon hot coals, readi¬
ly takes fire, and burns like refinous matter. After
the feparation of this matter, the liquid affords by eva¬
poration, a fait with a bafe of foda.
Three different faline fubftances have been obtained
by the action of acids on bile j the firft with a bafe of
foda, the fecond which cryftallizes in fmall needles has-
lime for its bafe, and the third is a cryftalline matter,
of a flightly fweet tafte, which is fuppofed to be fimilar
to fugar. Thus it appears that acids a£f on bile in
three different ways •, they coagulate the albumen,
which is precipitated j they combine with the foda,
by feparating the oily matter which conftitured the
faponaceous part of the bile 3 and they decompofe the
phofphoric falts.
Concentrated fulphuric acid coagulates bile in the
form of denfe flakes, and communicates to it a deep
colour. Nitric acid, after having formed a precipitate
of a green colour in the cold, aflumes a golden yellow
colour, when it is heated for a fufficient length of time.
It converts a portion of bile into oxalic and pruflic acids.
Muriatic acid at firft produces a green precipitate,
which aftenvards affumes a fhade of a reddiih vioret
colour, efpecialty by means of heat. Oxymuriatic acid
renders it white and turbid like milk. It changes the
properties of the different conftituents of bile, and oc-
I S T R Y.
cafions a precipitate fimilar to that matter which fre¬
quently conftitutes biliary calculi.
4. When the precipitate from bile by means of the
acids is treated with alcohol, and every thing foluble
in this liquid feparated, there remains a whitilh mat¬
ter, which is infufible, nearly infipid, infoluble, whe¬
ther with cold or hot water, but foluble in lolutions
of the cauftic fixed alkalies, which burns on red-hot
coals with the odour of horn, and which gives by ana-
lyfis, fimilar products, efpecially carbonate of ammo¬
nia in confiderable quantity. The coal which re¬
mains contains a portion of phofphate of lime.
5. The alkalies deprive bile of its bitter tafte ; but
they do not coagulate it.
6. Thus it appears that the conftituent parts of bile
are the following.
751
Component
4668
Phofphate
of lime.
4669*
Aftion of
alkalies..
Water,
Albumen,
Refin,
Soda,
Sulphurated hydrogen,
Saccharine matter,
Muriate of foda,
Phofphate of lime,
Phofphate of foda,
Iron.
7. Bile, it has been already obferved, performs anUfes.
important part in the funclion of digeftion. The al¬
buminous and laline parts combine with the chyle,
and are conveyed to the blood. The refinous portion
combines with the excrementitious part of the chyle,
and is thrown out of the body.
Bile is employed in the arts for removing fpots of
greafe and oil from woollen ftufts. It is alfo employ¬
ed as a pigment. It is evaporated and reduced to the
form of extraft, and diluted with a little water, in
which ftate it gives a brown colour.
III. Of Urine.
267X
r. The properties of urine vary confiderably, ac-Properties*
cording to the conftitution and health of the body,
and the period when it is voided after taking food.
The urine of a healthy perfon is of a light orange co¬
lour, and uniformly tranfparent. It has a flightly
aromatic odour, in fome degree relembling that of
violets. It has a flightly acrid, faline, bitter tafte.
The fpecific gravity varies from 1.005 to i o33-
The aromatic odour, which leaves it as it cools, is
fucceeded by what is called the urinous fmell, which
latter is converted to another, and finally, to an alka¬
line odour. Urine converts the tin&ure of turnfole
into a green colour, from which it is concluded, that
it contains an acid. _ _ 4674
2. By adding a folution of ammonia to frefli urine, phGfphate
a precipitate is formed in the ftate of white powder, of lime,
which is found to be phofphate of lime. But if lime
Water be employed in place of ammonia, a more copi¬
ous precipitate, of phofphate-of lime, is obtained, from
which it is concluded, that the phofphate of lime is
held in folution with an excels of acid. 4673
3. A fmall portion of magnefia is alfo found mixed PBWpkate
with the phofphate of lime which has been precipitat-^inakne-
ed, derived from phofphate of magnefia, which has112,
been decompofed by the alkali or lime. 2674
4. The froth which appears when urine is evapo-Carbonic
rated, is afcribed to the evolution of carbonic acid acid,
gas. *673
5. Urine which has been kept in new calks, depo-Carbonate
fits ume*
75 2
Component
Parts of
Animal
Subfti'nces.
u...   
a6;6
Uric acid.
CHEMISTRY.
r26;7
Rofacic
acid.
4678
Benzoic
acid.
4679
Albumen
and gela¬
tine.
a68o
Urea.
4681
Relin.
a(58a
Muriate of
foda.
2683
Muriate of
potafh.
fits fmall cryftals, which effiorefce in the air. Thefe
cryftals have been found to poffefs the properties of
carbonate of lime.
6. A brick-coloured precipitate is frequently form¬
ed in urine as it cools. This fubftance is uric acid,
which exifts in all urine, and may be obtained by eva¬
porating frelh urine, dilfolving it in pure alkali, and
precipitating by means of acetic acid.
7. The urine of perfons labouring under intermit¬
ting fevers, and fome other difeafes, depofits a copious
fediment called the lateritious fediment, which confills
of rofacic acid.
8. Benzoic acid alfo exifts in urine. It is obtained
by evaporating frefti urine to the confiftence of a fy-
rup, and adding muriatic acid. A precipitate is thus
formed, which is benzoic acid. But it may be obtained
by evaporating urine to drynefs, feparating the faline
fubftances, and applying heat to the refiduum. By
this procefs the benzoic acid is fublimed, and cryftal-
lized in the receiver. The quantity of benzoic acid
is more confiderable in the urine of horfes and cows
than in human urine.
6. Albumen or gelatine has been found in urine,
and is precipitated by means of an infufion of tan.
The cloud which appears as urine cools, confifts of
thefe fubftances, which are increafed in proportion du¬
ring different difeafes. The urine of perfons labour¬
ing under dropfy contains a large quantity of albu¬
men ; and in the urine of thofe perfons who are fub-
jedl to indigeftion, the albumen and gelatine are great¬
ly increafed.
10. Urea is the principal conftituent of urine. The
method of obtaining it from urine has been already
defcribed. It is to this fubftance that the tafte,
fmell, and peculiar charaflers of urine are owing.
If concentrated nitric acid be poured upon urine,
evaporated to the confiftence of fyrup, cryftals ap¬
pear, which are the nitrate of urea. The quantity
of urea fecreted is very different in different circum-
ftances. —
11. A refinous fubftance refembling the refin of
bile has been detefted in urine, to which its colour is
afcribed. Urine evaporated to the confiftence of ex-
trafr, mixed with fulphuric acid and diftilled, gives
out this refinous matter, w’hich is foluble in w^ater and
in alcohol. When urea has been feparated from urine
by evaporation and cryftallization, a faline mafs re¬
mains. If this be diffolved in hot wrater, and fpon-
taneoufly cryftallized in a clofe veffel, two kinds of
cryftals are depofited. Thofe at the bottom are in the
form of rhomboidal prifms, and confift of phofphate of
ammonia mixed with a little phofphate of foda. The
cryftals in the upper part of the veffel are in the form
of re&angular tables, compofed chiefly of phofphate of
foda. Thefe were formerly called fujible fait of urine,
microcofrnic fait.
12. Muriate of foda was the firft faline fubftance
dete&ed in urine. It may be -obtained by llowly eva¬
porating it to the confiftence of fyrup. The fait cry-
ftallizes upon the furface, but in this cafe the form of
the cryftals is that of an oftahedron, and not the cube,
the ufual form. The caufe of this deviation is afcribed
to the urea.
13. Muriate of potafh is alfo found among the
cryftals which are formed during the evaporation of Component
Urine. Parts of
14. Muriate of ammonia is one of the falls which s ^lrria*
are found in urine. The ciyftals of this fait whirh ^nceS*.
are ufually oftahedrons, when they are formed in 2684
urine affume that of the cube, a deviation which is Muriate of
alfo afcribed to the adlion of the urea.
15. Urine contains fulphur, which may be dete&ed
by holding paper ftained with acetate of lead over
urine when it is become putrid. The paper is black¬
ened, which is owing to fulphur exhaled with the car¬
bonic acid. Sulphate of foda and fulphate of lime
have been alfo detected in urine. 2686
16. No lefs than 30 different fubftances have been Component
detefted in urine by chemical analyfis, the principal ofParts*
which are the following.
Water,
Phofphoric acid,
Phofphate of foda,
Phofphate of foda and
ammonia.
Phofphate of ammonia,
Phofphate of lime,
Phofphate of magnefia,
Phofphate of magnefia
and ammonia,
Carbonic acid,
Carbonate of lime,
Uric acid,
Urate of ammonia,
Rofacic acid,
Benzoic acid,
Benzoate of ammonia,
Gelatine,
Albumen,
Urea,
Refin,
Muriate of potafti,
Muriate of foda,
Muriate of ammonia,
Sulphur,
Sulphate of lime,
Sulphate of foda.
2687
17. Urine is much difpofed to fpontaneous decom-Putrefac-
pofition. The time when this procefs commences, bon of
and the rapidity of the changes which take place, de-urme'
pend on the quantity of the gelatine and albumen.
When the proportion of thefe fubftances is confider¬
able, the decompofition is very rapid. This is owing
to the great number of fubftances, and the united
force of their attradlions overcoming the exifting affini¬
ties of the different compounds of which frefti urine
confifts, and efpecially to the facility with which urea
is decompofed. This fubftance is converted during
putrefaftion into ammonia, carbonic acid, and acetic
acid. Hence the fmell of ammonia is always recog¬
nized while urine is undergoing thefe changes. Part
of the gelatine is depofited in a flaky form mixed
with mucilage. Ammonia combines ■with phofphoric
acid, and the phofphate of lime is precipitated. It
combines alfo with phofphate of magnefia, and forms
a triple fait. The other acids, the uric, benzoic, the
acetic and carbonic acids, are all faturated with am¬
monia. The following fubftances, therefore, are ob¬
tained from urine by putrefaction.
Ammonia,
Phofpbate of ammonia,
Phofphate of magnefia and ammonia,
Carbonate of ammonia,
Urate of ammonia,
Acetate of ammonia,
Benzoate of ammonia,
Muriate of ammonia,
Muriate of foda.
Product;*
Component
Pai ts of
Animal
Saibltances.
26S9
Urine of
infants.
2690
After ta¬
iling food.
2691
In warm
feafons.
feven or eight
is completely
C H E M I
Produfts nearly flmilar are obtained by diftillation of
urine.
18. Such are the properties of human urine in its
healthy Hate ; the changes to which it is fubjeft, and
the produdls which are obtained, either by means of
chemical analyfis or fpontaneous decompofition. But
cirTumftan-the na^ure and properties of urine vary confiderably,
ces. according to the period of life, the time it is voided af¬
ter taking food, different feafons of the year, the
nature of the food, the influence of paflions, and dif-
eafe.
In the urine of infants, no phofphate of lime is
found. The proportion of benzoic acid is confider-
able, and the quantity of urea is fmall. There is lefs
acrimony, odour, and colour. As the period of life
advances, the faline matters increafe, efpccially the
phofphate of lime, which is no longer required for the
formation of bone.
The urine, which is pafled immediately after taking
food, is white and colourlefs, and feems to contain
little elfe but water. It is not till
hours after a repaft, that the urin
formed.
Urine voided during the warmer feafons of the
year, or by perfons wdio inhabit hot climates, is high-
coloured and acrid, which is aferibed to a greater pro¬
portion of faline matter and urea. In wdnter alfo the
urine is red and high-coloured, owing to a greater
proportion of the earthy phofphates and of uric acid,
which it then contains. It is no doubt confiderably in¬
fluenced by the modification of the aftion of the fkin.
The food frequently communicates its properties to
the urine. The odour of garlic, of refinous fubftances,
and fome aromatics, is often perceptible in the
urine a few minutes after thefe fubftances are taken in¬
to theftomach, or even only applied to the flrin. The
fetid odour of the urine of thofe who have eaten afpa-
ragus, is well known. The colouring matters of
fome fubftances are communicated to the urine 5 fuch
as the red colour of beet-root, the orange-yellow of
rhubarb, or the colour of madder.
The paflions of the mind have great influence on
the fecretion of urine, both in changing its properties,
and increafing its quantity. In thefe cafes the urine is
generally colourlefs, infipid, and without odour.
But the nature and properties of urine undergo ftill
greater changes during difeafe. From thefe changes
the empiric has attempted to form prognoftics of the
nature, progrefs, and termination of difeafes.
At the commencement of fevers and inflammatory
diforders, the urine is high-coloured, and extremely
acrid, fcarcely becomes turbid on cooling, and depofits
no fediment. In afl’edtions of the liver, fuch as jaundice,
it is of a yellow orange colour, like faffron, and com¬
municates its colour to the vefiels into which it is
received, or to thofe fubftances wdiich are immerfed
in it. It is then called bilious urine. It feems to
contain a portion of the colouring matter of bile. To¬
wards the termination of febrile diforders, the quantity
of urine is increafed, and it depofits, as it cools, a cry-
ftalline or fcaly matter, of the colour of peach flowers,
which is called critical urine. The fediment is com-
pofed of phofphate of lime, rofacic and uric acids.
During nervous affeftions, as in hyfteria, the urine is
perfe&ly limpid and colourlefs, inodorous and infipid.
Vol. V. Part II.
7S3
2592
Kinds of
food.
2<%>3
Paflions.
2594
Difeafes.
S T R Y.
It has been obferved, that the unne of gouty perfonsComponent
contains a fmaller proportion of acid than ufual. At Parts °f
the commencement of a paroxyfm, the quantity ofc
phofphoric acid feems to be diminiftied; but it gradu-
ally increafes towards the termination of the fit, and is
then in greater proportion than in ordinary health.
The urine of perfons labouring under rickets, depofits
a great portion of lime. The urine of an infant who
died of worms, was found on analyfis to contain oxa¬
late of lime. In fome cafes of diabetes, the urine is
colourlefs and infipid ; in others it contains a great
proportion of faccharine matter.
19. The urine of other animals exhibits different Different
charafters from that of man, according to their na-animab*
ture, the diverfity of their organs, their food, man¬
ner of refpiration, and the medium in which they
live* 2695
The urine of the horfe has a ftrong peculiar odour. The horie.
It is turbid when voided, or foon after becomes mud¬
dy. A pellicle, which is carbonate of lime, forms
on the furface when it is expofed to the air. It
changes the fyrup of violets to a green colour, effer-
vefees with acids, and is precipitated by the alkaline
carbonates. The urine of the horfe yields no phofpho-
rus. The component parts of the urine of this animal,
as they have been afeertained by Fourcroy and Vau-
quelin, are the following :
Carbonate of lime,
Carbonate of foda,
Benzoate of foda,
Muriate of potalh,
Urea,
Water and mucilage,
0.0 T l
O.OO9
O.O24
O.OO9
O.OO7
O.94O
I .OOO '
* Mem. dt
I'InJ}. ii.
P- 445-
2697
The urine of the cow poffeffes nearly the fame pro-The cow,
perties as that of the horfe. It has a foapy feel, and
a ftrong peculiar odour. It gives a green colour to
fyrup of violets, effervefees with acids, and is not al¬
tered by the alkaline carbonates. When it is expofed
to the air, fmall cryftals form on the furface. Its
component parts are,
Carbonate of potafli,
Sulphate of potafli,
Muriate of potafti,
Benzoic acid, ,
Urea.
The urine of the camel is more diftinguiftied by its The camel,
odour than any other, but it is analogous to that
of the cow. It is not mucilaginous, and does not
depofit carbonate of lime. The fpecific gravity of
this urine is greater than any other. Tt produces a
flight change on the infufion of violets, communicating
a green colour. It effervefees with acids, and fur-
nifties nitre, fulphate and muriate of potafti, with the
addition of fulphuric, nitric, and muriatic acids. It
contains
Carbonate of potafti,
Sulphate of potafti,
Muriate of potafti,
Urea.
2<?9f
The urine of the rabbit, examined by Vauquehn, xhe rabbit
5 C exhibits
754
Component
Parts of
Animal
Subftances.
CHEMISTRY.
2706
Guinea pig
2701
Graminivo
rous ani¬
mals.
2702
Carnivor-
2703
Of birds.
2704
Turtle.
27°S
Properties.
2706
Of cows
milk.
2707
Separation
of cream.
exhibits fimilar chara&ers with that of the horfe, the
cow, and the camel. It becomes milky, and depofits
carbonate of lime by expofure to the air. It con¬
verts vegetable blues to a green colour, and effervef-
ces with acids. It contains the following fubltances.
Carbonate of lime,
Carbonate of magnefia,
Carbonate of potalh,
Sulphate of potalh,
Sulphate of lime,
Muriate of potalh,
Urea,
Gelatine,
Sulphur.
The urine of the Guinea pig is analogous in its na¬
ture and properties to that of the larger animals alrea¬
dy defcribed.
It appears that the urine of graminivorous animals
belonging to the clafs of mammalia, or which live on
vegetables in general, contains no phofphoric falts, or
uric acid j that it is loaded with carbonate of lime,
falts having a bafe of potalh, and benzoic acid. The’
only fubflance which the urine of thefe animals poffef-
fes in common with human urine, is urea. The
urine of carnivorous animals, of which indeed fcarcely
any thing is known, is fuppofed to poffefs different
properties from that of the animals juft mentioned.
rI he ftrong fetid odour of the urine of the cat is well
known. Muriate of ammonia has been obtained from
the urine of this animal by evaporation; but it is fup¬
pofed, from the peculiar odour, that it contains urea.
The urine of birds affords a copious fediment, which
feems to be carbonate of lime.
A fubftance which was found in the urinary blad¬
der of the turtle in the form of pafte, and which was
examined by Vauquelin, was compoled of
Muriate of foda,
Phofphate of lime,
Animal matter,
Uric acid.
IV. Of Milk.
1. Milk, which is fecreted in particular organs by
the females of viviparous quadrupeds and cetaceous
n nes, included under the clafs mammalia, and deftin-
cd for the nourilhment of the offspring, is a white
opaque Hind varying i„ its properties, according to
the different Ipecies of animals, and the nature of their
lood. 1 he milk of the cow, which is moft eafily and
niou abundantly procured, has been chiefly the fub
jeft of chemical inveftigation. To it, therefore, the
following obfervations are chiefly applied.
2. Muk is difhnguiftied by an agreeable fweet tafte
and a peculiar fmell. But thefe properties belong to
it only when it is juft feparated from the cow, for in
tne courfe of a few hours they are confiderably differ¬
ent. 1 he fpecific gravity varies at different periods
It is greater than that of water, and has been found
to amount to 1.0324 The boiling and the freezing
points of milk are alfo variable. 6
. 3- If rai;k be left at reft for fome time, it feparates
into two parts ; an unftuous matter, which floats on
the furface, called cream, and a denfer fluid which ftill
retains many of the properties of milk. The quan-Component
tity of cream obtained from milk, and the time it re- ■Parts oi
quires to feparate, vary according to the nature of the c f£imaI
milk and the temperature. ?ubfl*nces;
4. Cream thus obtained is of a yellow colour, and
acquires a greater confiftence by being expofed to theItSp^8er-
air. It is lighter than water, has an un&uous feel, ties, e^",
and becomes rancid like oils, by keeping. When
it is boiled, a fmall portion of oil appears on the fur-
face. Cream is not foluble in alcohol or in oils.
When cream is agitated for a longer or fhorter time,
according to the temperature to which the milk has
been expofed during its feparation, and perhaps to
fome circumfiances which have not yet been obfer-
ved, it feparates into two parts; one, which has a
folid confiftence, is butter, and another which remains
fluid.
5. Butter is of a yellow colour, and has all the pro-Butterf
perties of an oil, combined with a portion of the curd
and ferum of the milk. It melts at the temperature of
96°, and mixes readily with other oily matters. When
butter is kept for fome time, it is decompofed ; it be¬
comes rancid, which is afcribed to the whey and the
curd with which it is combined ; for when thefe fub-
ftances are previoufly feparated, it may be preferved
fweet much longer. Butter yields by diftillation wa¬
ter, an acid liquid, an oily fubftance, which is at firft
fluid, but becomes afterwards concrete. A fmall por¬
tion of carbonaceous matter remains behind.
6. When frefh cream, or the whole of the milk frefh in
drawn from the cow’, is churned, it requires the procefs the^roceft
to be continued a much longer time than when the of churn-
cream or milk is left to repofe, as is ufually the cafe^’g-
till it has acquired a flightly acid tafte. But when
cream, which has become four, is churned, the butter
feparated has no acid properties, and the milk which
remains is even lefs four than the cream previous to
the commencement of the procefs. An acid, therefore,
has been evolved, and this acid is fuppofed to be the
carbonic. When frefh cream or frefli milk is fubjedt-
ed to this procefs, in which the acid has not been form¬
ed, it requires greater agitation to complete this pre¬
vious part of the change w-hich the cream or milk mull
undergo, before the feparation of the oily part or the
butter. The milk which remains after the butter has
been feparated, or, as it is called, the butter-milk, has
all the properties of milk from which the cream has
been feparated.
7. The milk which remains after the feparation ofcoaguLa-
the cream, maybe coagulated by the addition of fe-tion.
vend fubftances, particularly by the addition of rennet
wliich is in moft common ufe, and which is prepared
by drgefting the inner coat of the ftomach of young
animals, elpecially that of the calf. This coagulum
feparates into two parts, the curd and the ferum or
whey.
Curd is a white folid fubftance, and fomewhat brit-Curd!1*
tie, when the whole of the whey is expreffed. It is
foluble in acids, but it is neceffary that the mine¬
ral acids be greatly diluted, and the vegetable acids
concentrated.
Cheefe is prepared from curd, by feparating there
whey by expreffion. The quality of the cheefe depends ** C’
upon the quantity of cream which remains in the
milk.
CHEMISTRY.
Component milk. Tlie beft cbeefe is obtained by coagulating the
Animat at t^e temPerature about ioo°, and expreffing
Subftaaces. the whey flowly and gradually, without breaking down
u—the curd.
If milk be not too much diluted with water, it may
be coagulated by a great number of different fab-
ftances. Among this number are acids, alcohol,
2714 neutral falts, gum arable, and fugar.
Whey. 8. Whey expreffed from coagulated milk is of a
yellowifh green colour, and has an agreeable fweet
tafte. If it is boiled, a quantity of curd feparates,
and after being left at rell for fome time, the whole
of it is precipitated, and the liquid remains tranfparent
and colourlefs. By flow evaporation it depofits white-
coloured cryftals of fugar of milk, with fome muriate
of potafh, muriate of foda, and a little phofphate of lime.
The liquid which remains after the feparation of the
falts, is converted, by cooling, into a gelatinous fub-
ftance. If whey be kept for fome time, it becomes
four, by the formation of an acid, which is ladlic
acid. It is to this acid that the fpontaneous coagula¬
tion of milk, after it remains at reft for fome time, is
2715 owing.
Koumils. 9. If milk, after it has become four, be kept in a
proper temperature, it ferments, emitting carbonic acid
gas, and exhibiting the other phenomena of fermenta¬
tion. A vinous intoxicating liquor is thus prepared,
which has been long known among the Tartars, and
called by them koumifs. They prepare it from the
2715 milk of the mare.
‘Vinegar, jq. Milk is fufceptible of the acetous fermentation.
If about fix fpoonfuls of alcohol be added to eight
pints of milk, and the liquid be excluded from the
air, vinegar will be formed in four or five weeks. Al¬
though the air is to be excluded, yet the carbonic acid
gas muft be allowed to efcape as it is difengaged.
By the diftillation of milk with the heat of a water-
bath, water paffes over, after which the milk coagulates,
and an oily yellowifh white fubftance remains behind,
which, by increafing the heat, yields a tranfparent li¬
quid, a fluid oil, ammonia, an acid, a thick black oil,
and in the end carbonated hydrogen gas. The coaly
matter in the retort contains potafh, muriate of pot¬
afh, phofphate of lime, and fometimes muriate of foda,
with a fmall portion of magnefia and iron.
The conftituent parts which enter into the compo-
fition of milk, are the following :
1. Water, 6. Muriate of foda,
2. Oil, 7. Muriate of potafh,
3. Curd, 8. Phofphate of lime,
4. Gelatine, Sulphur.
5. Sugar of milk,
271S
Milk dif- II. Although the milk of different animals be com-
ferent in pofed nearly of the fame fubftances, the proportions
different vary f0 as to give them very different properties.
The following are the refults of the inveftigations of
27£9 Deyeux and Parmentier with regard to the proper-
‘ L ‘ ties of the component parts of the milk of different
animals compared together.
A. Every kind of milk when left at reft, produces
cream on the furface, but it is different in the milk of
different animals.
a. In the milk of the cow it is copious, thick, and
of a yellow colour.
2717
Compofi-
tion.
75’J’
b. In women’s milk it is more liquid, white, and in Component
imall quantity. Parts of
c. In goats milk it is more abundant than in that of
the cow, thicker and whiter. Subftances,
r/. In ewes milk it is nearly as abundant, and of the
fame*colour as that of the cow, but has a peculiar tafte.
c. In affes milk it is thick, lefs abundant, and in
a great meafure refembles that of women’s milk.
f' bi mares mihi it is very fluid, and fimilar in co¬
lour and confiftence to good cows milk before the cream
appears on the furface.
B. Butter obtained from the milk of different ani- 112s
mals, has the following comparative properties. Butter.
a. That of the cowr is foinetimes of a deep yellow
fometimes pale or white, and has always a confiderable
ConfiftenCy.
bk It is difficult to feparate the butter from the cream
of women’s milk. It is in fmall quantity, infipid, and
of a pale yellow. It has been erroneoufly fuppofed
that no butter could be obtained from this milk.
c. I he butter of affes milk is always very white,
foft, and readily difpofed to become rancid.
d. The butter from goats milk is eafily feparated
from the cream. It is abundant, always white, foft,
and difpofed to become rancid.
e. The butter from ewes milk is of a yellow colour,
foft, and foon becomes rancid.
f. The butter of mares milk is difficult to be ob¬
tained and in fmall quantity. It has little confiftence,
and is readily decompofed.
C. The curd of milk varies in different animals. Curd7.1 2*
a. That from the milk of the cow' is bulky, tremu¬
lous, and retains a great deal of the ferum.
b. That from women’s milk is in fmall quantity,
little coherent, has an unftuous feel, and retains but a
fmall portion of the whey.
c. The curd of affes milk is fimilar to the former,
but without being unftuous.
d. Curd from the milk of the goat is in great pro¬
portion, of a firmer confiftence than that of the cow,
and retains lefs whey.
e. Curd from ew^es milk is fat, vifeid, and communi¬
cates a foft pafte to cheefe.
_ f' The curd from mares milk is in very fmall quan¬
tity, and fimilar to that from women’s milk.
D- The ferum or whey conftitutes a very great pro- whey!3 4 5
portion of the milk, and exhibits the following va¬
rieties.
a. Whey from the milk of the cow is of a greenifh-
yellow colour, a fweet tafte, and contains fugar of milk
and neutral falts.
b. The whey from women’s milk has little colour,
but has a very fweet tafte, containing a confiderable
propoition of faccharine matter.
c. I he whey of affes milk is colourlefs, and contains
lefs falts and more fugar than that of the cow.
d. Whey of the goat is of a flight yellow colour,
and contains very little fugar and faline matter. The
latter confifts almoft entirely of muriate of lime.
e. The whey of ewes milk is always colourlefs, and
contains the fmallert quantity of fugar, and but a fmall
portion of muriate and phofphate of lime.
f khe whey of mares milk has little colour, and
contains a great proportion ofiaccharine matter and of*
faline fubftances*. ix-
5 C 2 V, Of
75 6
C H E M
Component
Parts of
Animal
Subftances.
2723
Properties.
2724
Combines
with oxy-
gen.
2725
A chon of
acids, &c.
2725
Diftillation.
V. Of Saliva.
1. The faliva which is fecreted by peculiar glands,
and which flows into the mouth, is a clear, vifcid fluid,
without tafte or fmell. Its fpecific gravity varies from
1.0167 to 1.080. It has generally a frothy appearance,
being mixed with a quantity of air.
2. Saliva has a ftrong attra&ion for oxygen, which
by trituration it communicates to fome metallic fub-
ftances, as mercury, gold, and filver. When faliva
is boiled in water, albumen is precipitated, and when
it is flowly evaporated, muriate of foda is obtained.
A vegetable gluten remains behind, which burns
with the odour of prufiic acid.
3. Saliva becomes thick by the aftion of acids.
Oxalic acid precipitates lime. Saliva is alfo infpiffated
by alcohol. It is decompol’ed by the alkalies j and the
nitrates of lead, of mercury, and of filver, precipitate
muriatic and phofphoric acids.
4. By diftillation in a retort, it froths up, affords
near four-fifths of its quantity of wmter nearly pure, a
little carbonate of ammonia, fome oil, and an acid.
What remains behind confifts of muriate of foda, phof-
phate of foda and of lime. The conftituent parts of
faliva are the following.
2727
Compoli-
tion.
2728
Saliva of
the hoife.
2729 _
Pancreatic
juice.
1. Water. 5. Phofphate of fo 'a.
2. Mucilage. 6. Phofphate of lime.
3. Albumen. 7. Phofphate of ammonia.
4. Muriate of foda.
5. The faliva of the horfe is of a greenifh yellow
colour, a difagreeable fmell, a faline tafte, and foapy
feel. It is coagulated by the acids, alcohol, and boil¬
ing water. A black earthy refiduum remains after
fpontaneous evaporation. By diftillation it yields an
infipid watery liquid, carbonate of ammonia, carbonat¬
ed hydrogen and carbonic acid gafes, and a black
empyreumatic oil.
6. The pancreatic juice, it is fuppofed, pofTefles pro¬
perties analogous to thofe of faliva, and is deftined for
fimilar purpofes, namely to contribute to the folution
of alimentary fubftances, and to their converfion into
chyme , but very little is known of its nature and
ufes.
2730
Parts of
the eye.
* PM.
tIranf.
1802.
27.31
Eyes of
Iheep.
VI. Of the Humours of the Eye.
I. The eye is compofed of three fubftances which
in anatomy have received the name of humours. Thefe
are the aqueous, the vitreous, and the cryflalline
humour or lens. The following obfervations are from
Mr Chenevix’s experiments on this fubjeft *.
z. The aqueous humour of the eye of the iheep is tranf-
parent like water, and has Icarcely any tafte or fmell.
The fpecific gravity is 1.0090. It evaporates flowly
when expofed to the air j a coagulum is formed by
boiling. When 100 parts are evaporated to drynefs,
eight parts remain behind. None of the metallic falls
produce any precipitate except nitrate of filver, which
throws down the muriate of filver. Tan alfo produces
a precipitate in the aqueous humour. The component
parts, therefore, of this fubftance are albumen, gelatine,
and muriatic acid, or rather muriate of foda, as the
acid is in combination with foda. The vitreous humour
exhibited the fame properties.
1 s T r Y. ’
3. The cryftailine lens of the llieep is folid, com-Component
poled of concentric coats, and tranfparent. The fpe- f>ar.ts ot'
cific gravity is l.l. It has fcarcely any tafte wTensubftar;ces
it is frefh. It is foluble in water, and the folution is >
coagulated by heat. Tan produces a copious precipi¬
tate, both before and after coagulation. Its com¬
ponent parts are, therefore, albumen and gelatine, with
water.
4. The human eye was found to be compofed of Human
the lame fubftances. The fpecific gravity of the aque-eye.
ous and vitreous humours is 1.0053 ? th6 cryftailine
lens, 1.0790. The fpecific gravity of the aqueous
and vitreous humours of the eye of the ox is 1.008;
the cryftalline lens 1.0765. The compofition is the
fame as that of the fheep.
VII. Of Tears and Mucus.
1. The tears are fecreted by the lachrymal gland, properties,
for the purpofe of lubricating the eye. This liquid is
tranfparent and colourlefs, has no perceptible fmell,
but a faline tafte. It communicates to vegetable blues
a permanent green colour. When it is evaporated
nearly to drynefs, cubic cryftals are formed, which
are muriate of foda. Soda is in excefs, becaule vege¬
table blues are converted by it to a green colour. A
portion of mucilaginous matter, wdiich becomes yellow
as it dries, remains after the evaporation. This liquid
is foluble in water and in alkalies. Alcohol produces
a wftiite flaky precipitate, and wdien it is evaporated
muriate of foda and foda remain behind. By burning
the refiduum, fome traces of phofphate of lime and of
loda are detefted. The component parts of tears, are,
therefore.
Water,
Mucilage,
Soda,
Muriate of foda, Compofi-
Phofphate of lime, *ion.
Phofphate of foda.
The mucilage of tears abforbs oxygen from the at-
mofphere and becomes thick, vifcid, and of a yellow
colour. It is then infoluble in water. Oxymuriatic
acid produces a fimilar efTedl. It is converted into
muriatic acid, fo that it has been deprived of its oxy-
gen.
2. The mucus of the nofe confifts of the fame fub- ;viucusf
fiances as the tears ; but being more expofed to the
air, it acquires a greater degree of vilcidity from the
mucilage abforbing oxygen.
VIII. Of the Wax of the Ear.
1. The wax of the ear, or cerumen, is a liquid fecreted properties,
by glands, which are fituated in the internal ear. It
is of a vifcid yellow colour, and becomes concrete by
expofure to the air. The tafte is hitter ; it melts with
a moderate heat, gives out an aromatic fmell, and
ftains paper like oil. When thrown upon burning
coals, it gives out a white fmoke, melts, fwells, becomes
dark-coloured, and gives out the odour of ammonia.
A light coaly matter remains behind. It forms a kind
of emulfion by agitation with w-ater.
2. Alcohol diflolves a portion of cerumen ; the un- Adlion'of
diffolved part exhibits the properties of albumen mixed alcohol,
with oil. By evaporating the alcohol, an orange colour¬
ed refiduum, fimilar to turpentine, is left behind. It has
the properties of refin of bile. This matter is alfo fo¬
luble
C H E M I
Component fable in ether. By burning the albumen of the ceru-
Parts of men> fame traces of foda and phofphate of lime are de-
Animal
Subftances.
tefteck The component parts of cerumen are.
2738
Compoti-
tion.
Albumen,
Refin,
Colouring matter,
Soda,
Phofphate of lime.
*739
Properties.
2740
Action of
water.
2741
Acids.
2742
Salts fepa-
rated.
2743
Compofi-
tion.
IX. Of Synovia.
1. The liquid fecreted within the capfalar liga¬
ments of the joints, to facilitate motion by lubricating
thefe parts, is called fynovia. The fynovia of the ox.
is a vifcid, femitranfparent fluid, of a greenilh-white
colour, wrhich foon acquires the confidence of jelly, and
not long after becomes again fluid, depofiting a fila¬
mentous matter.
2. Synovia mixes with wTater, and renders it vifcid.
When this mixture is boiled, it becomes milky, and
fame pellicles are depofited on the fides of the veffel.
Alcohol produces a precipitate when added to fynovia.
This precipitate is albumen. After this matter is fe-
parated, the liquid {till remains vifcid j but if acetic
acid be added, the vifcidity difappears, and it becomes
tranfparent, depofiting a white filamentous fabftance,
which refembles vegetable gluten. It is foluble in
cold water, and in concentrated acids and pure alka¬
lies. This fibrous matter is precipitated by acids and
alcohol in flakes.
3. The concentrated mineral acids produce a flaky
precipitate, which is foon rediflblved ; but the vifci¬
dity of the liquid is not deitroyed till they are fo
much diluted with w'ater, that the acid tafte is only
perceptible.
4. When fvnovia is expofed to dry air, it evapo¬
rates, and cubic crystals remain in the refiduum with
a white faline efflu/efcence. The firft are muriate of
fada, and the latter carbonate of foda. This fubftance
foon becomes putrid, giving out ammonia during its
decompofition. By diftillation in a retort, it yields
water, which foon becomes putrid j water containing
a portion of ammonia, and an empyreumatic oil, with
carbonate of ammonia : by wafhing the refiduum, mu¬
riate and carbonate of foda may be obtained. A
fmall portion of phofphate of lime is found in the
coaly matter. The confiituent parts of fynovia are
the following :
Fibrous matter 11.86
Albumen 4-52
Muriate of foda 1 75
Soda 00.71
Phofphate of lime 00.70
Water 80.46
* Annul, dt
Cbim. xiv.
p. 123.
I 00.00 *
X. Of Semen.
2744 1. Semen is fecreted in the teftes of male animals j but
^ when it is ejeffed it is compofed of two iubicancesj the
one is fluid and milky, and the other of a thick mucila¬
ginous confiftence, in which appear a great number
of white filky filaments, efpt cially if it be agitated in
cold water. It has a difagreeable odour, and an acrid
2
S T R Y. 757
irritating tafte. The fpecific gravity varies confider-Component
ably, but is always greater than that of water. When
it is rubbed in a mortar, it froths up, and acquires the 5 ub ft antes,
confiftence of pomatum from the air with wdrich it y—'
mixes. It converts the flowers of mallow and of vio¬
lets to a green colour, and it precipitates the calcare¬
ous and metallic falts j which (hews, that it conta ns an
uncombined alkali. The thick part of the femen as
it cools, becomes tranfparent, and affumes a greater de¬
gree of confiftence j but it afterwards becomes entire¬
ly liquid, even without abforbing moifture from the
air. This change takes place in about twenty minutes
from the time of its emiflion.
2. If femen be expofed to the air after it has become Adtion of
liquid at the temperature of 6o°, it becomes covered air.
with a tranfparent pellicle, and at the end of three or
four days depofits fine tranfparent cryftals of a line
in length, crofting each other like radii from a
center. When they are magnified, they appear to be
faur-fided prifms terminated by long four-fided pyra¬
mids. When femen is expofed to a warm air, in con-
fiderable quantity, it is decompofed j it affumes the
colour of the yolk of egg, and becomes acid, either
by abforbing the oxygen from the atmofphere, or by
a different combination and arrangement of its own
conftituent principles. It then emits the odour of
putrid fifli, and is covered with the byjfus Jeptica. 2?46
3. Heat accelerates the liquefaftion of femen j and offieat.
when it has undergone this change it is no longer
fufceptible of coagulation. It is decompofed by the
application of ftrong heat. Water is firft feparated;
it then blackens, fwells up, and emits yellow fumes,
having an empyreumatic, ammoniacal odour. A light
coal remains behind, which burns readily to wdiite
allies.
2747
4. Before it has become fluid, femen is not foluble Of water.-
in water either cold or hot. To the latter it commu¬
nicates an opal colour. But in the fluid ftate it com¬
bines readily with either hot or cold water, from which
it is feparated by alcohol or oxymuriatic acid in the
form of white flakes. The alkalies promote the folu-
tion of femen in water. 274S
5. No ammonia is difengaged from frelh femen by Of lime,
means of quicklime but when it has been expofed
for fame time to a warm and moift air, it is feparated
in great abundance, fo that ammonia is formed during
its expolure to the air. 2749
6. The acids readily diffolve femen, and this folution Acids,
is not decompofed by the alkalies } nor indeed is the
alkaline folution of femen decompofed by the acids..
Wine, cyder, and urine alio diffolve femen, but it is
in confequence ox the acid which is combined with
thefe liquids. Water acidulated with fulphuric acid
acquires the fame property. Oxymuriatic acid coagu¬
lates femen in wdute flakes which are infoluble in wa¬
ter and in acids. The fame acid produces the coagu¬
lation of fluid femen. This is owing to the ablorption
of oxygen derived from the acid which is converted
into muriatic acid. _ 2750
7. Barytic falts are not decompofed by the feminal Salts,
fluid wdrich has been liquefied in a clofe veffel ; but
w’hen it has undergone this change in the open air,
rhomboidal cryftals are formed with the addition of
thefe falts. The calcareous and metallic falts are de-
comoofed by femea in both conditions. Irom thefe
faffs
75 S CHE M
Component fafts it appears that femen contains an uncombined al-
Anima°lf kal*’ .which h?S ,not the ProPert:y ef decompofing the
Subftances. barytic falls till it has combined with the carbonic acid
—v~~.... from the atmofphere.
8. 1 he cryftsls which form in femen by fpontane-
I s T R Y.
2751 .
Semen con- ous evaporation in the open air, and which are en-
tangled in the vifcid matter, may be feparated by add-
lime.6 ° water- Thefe cryftals have neither fmell nor tafle.
1 hey melt under the blow-pipe into a white opake
globule which is furrounded with a yellowilh flame.
This fait is infoluble in water, and is not afted on by
the alkalies ; but is foluble in the mineral acids with¬
out effervefcence, from which folutions, lime water,
the alkalies, and oxalic acid throw down a precipitate.
Alcohol added to the concentrated muriatic folution
of this fubflance, diffolves part of it, which exhibits all
the charafters of muriate of lime j and there remains
another fubftance which melts under the blow-pipe in¬
to a .green tranfparent glafs foluble in water, which
precipitates lime water and reddens vegetable blues.
This -fait, therefore, as is demonftrated from thefe ex¬
periments, is phofphate of lime. After the formation
of the above falls, a great number of fmall, white,
opake bodies appear on the furface. They are alfo
phofphate of lime.
. 9* By burning 40 grains of dried femen in a cru¬
cible, it firfl: became foft, and then gave out the odour
of burnt horn accompanied with yellow fumes. It
blackened and emitted the odour of ammonia. The
coaly matter which remained was lixiviated with w^ater.
This was evaporated and afforded cryflals in the form
or rhomboidal plates, which effervefced with acids •
with fulphuric acid afforded fulphate of foda, and with
muriatic acid formed muriate of foda. The alkali,
therefore, was foda.
10. The alkaline matter being feparated, the refi-
duum was ftill expofed to ftrong heat, and furnifhed
13 grs. of white allies which had the following pro¬
perties. By the aclion of the blow-pipe it is convert¬
ed into an opake white enamel which attra&s moilture
from the air, is foluble in acids, and the folution has all
the characters of phofphate of lime. The component
parts of femen therefore are
2752
And foda.
2753
Compoli-
tion.
* Vauque-
Hn, Ann- de
Cbim. ix.
64—80.
Water
Mucilage
Soda
Phofphate of lime
90
6
100 *.
XI. Of the Liquor of the Amnios.
I. I his liquid is fecreted in the amnios or bag which
urrounds the fetus in the uterus. It is very different
m different animals, fo far at leaft as its nature and
* Ann. dc ProPertles have been mveftigated. The liquor of the
Chim. a™nios f women and cows only has been examined
xxxni. 269. Phe following are the refults of the experiments of
2754 v auquehn and. Bumva on thefe liquids *.
Properties. 2. T his liquid in women is of a milky colour, an
agreeable odour and a faline tafte. It becomes tranf¬
parent by filtering and feparating feme coagulated
matter which is fufpended m it, and which communi¬
cates the white colour. The fpecific gravity is 1.00c.
Xt leems to contain both an acid and an alkali j for it
converts fyrup of violets to a green colour, and red-Component
dens the tinfture of turnfole. It froths when agitat- X,arts °f
ed, becomes opaque when heated, and exhales thec77mal
odour of the white of egg. ubilances.
3. It is rendered more tranfparent by acids; but 2755
alcohol and the alkalies occafion a flaky precipitate, Adtion of
which is like glue when it is dried. The infufion ofheat-
nut-galls gives a copious browm precipitate ; and ni- 2756
trate of filver produces a white precipitate, which be-Acids*
ing infoluble in nitric acid, is muriate of filver.
4. By flow evaporation this liquid affumes a milky
appearance ; a tranfparent pellicle forms on the fur-
face, and a very fmall refiduum is left. By adding
W'ater to the refiduum, and evaporating the lolution,
muriate and carbonate of foda are obtained. The alli¬
es which remain, after burning the refiduum, confilt
of carbonate of foda, phofphate and carbonate of lime.
During the burning a ffrong, fetid, ammoniacal odour
is exhaled.
5. From thefe experiments, it appears that this li-c /75£
quid confifls of a great proportion of water, of albu-tion^0 "
men, muriate of foda, of foda, phofphate of lime, and
lime.
6. A white Ihining foft fubftance, fomewhat refem- 2758
bling foap, is depofited on the body of the fetus in fruftonthe
the uterus.. It is. infoluble in water, alcohol, and oils.™'
The cauftic alkalies diffolve a portion of it, and form
a kind of ioap. It decrepitates on burning coals, then
dries, blackens, and gives out the odour of an em-
pyreumatic oil. It leaves behind a coaly matter,
which burns with difficulty. When it is heated
in a crucible of platina, it decrepitates, while an oily
matter exudes. It then curls up like horn, inflames,
and leaves behind gray allies, which effervefee with
acids, and which feem to be compofed chiefly of car¬
bonate of lime.
. 7- This matter feems to be a mixture of animal mu- Comnofi
cilage and fat, originating from the albumen, which tion.
has undergone fome peculiar change^ The parts of a
fetus, which have remained in the uterus after death
have been found converted into a fatty matter.
Liquor of the amnios of the cow.—x. This liquid
differs from the former in being of a reddifh brown G,nara<^ler*,
colour, in having an acid bitter tafte, an odour refem-
bhng the. extrafts of fome vegetables, and the vifeidi-
ty of a folution of gum. The fpecific gravity is 1.028.
It reddens the tinefture of turnfole, forms a copious
precipitate wbth muriate of barytes, and with alcohol
a precipitate of a reddifh matter.
2. When it is evaporated, a thick feum forms on . 2?5r.
the furface, which is eafily feparated, and which, on
cooling, is found to. contain white cryftals of a flight-
ly acid .tafte. A vifcid matter like honey appears, by
continuing the evaporation. WTen this matter is
treated with boiling alcohol, it furnifhes, on cooling,
an acid which cryftallizes in fhining needles. This is
the ammotic acid which has been already deferibed.
I he matter which remains after the feparation of the
cryftals is infoluble in alcohol, and is firm and tena¬
cious.
3. Having extraded the whole of the acid, if the 9
evaporation be continued till the liquid acquire theoffodf*
confiftence of a fyrup, large tranfparent cryftals are obtained,
formed, which have a bitter tafte, and are foluble in
water. Thefe cryftals were found to be fulphate of
foda,
/
C H E M I
?7<3
Animal
matter.
Component foda, wliiclt are obtained in a ftate of purity, by burn-
Parts of jng ^ refiduum 0f a quantity of the liquid evaporat¬
ed to dryhefs, diffolvxng the coaly refiduum in water,
and evaporating.
4. The animal matter which accompanies the faline
fubftances, is of a reddifh brown colour and a peculiar
tafte, very foluble in water, but infoluble in alcohol,
which even feparates it from water. It neither com¬
bines wuth tan, nor is it fufceptible of being con¬
verted into jelly, fo that it does not poffefs the proper¬
ties of animal mucilage. When it is heated ftrongly,
it fwells up, exhales at firft the odour of burning mu¬
cilage, afterwards that of ammonia and an empyreu-
matic oil ; and, at laft, that of pruffic acid. When
it is burnt, there remains behind a bulky coal, the
afhes of which are white, and contain phofphate of
magnefia and a fmall portion of phofphate of lime.
5. The conflituent parts of the liquor of the am¬
nios of the cow, are the following.
2754
Compofi-
tion.
Water,
Acid,
Sulphate of foda,
Animal matter.
XII. Of Fluid Morbid Secretions.
I. During the difeafed adtion of the veffels of different
parts of the body, liquids are fecreted, as, for in-
llance, when the mufcular or bony parts are wounded,
a matter is exuded, which continues to flow till the
wound is healed up •, in dropfical dileafes a liquid is
fecreted in the different cavities of the body; and wdien
the fkin is irritated by the adfion of blifters, a fluid
collefts between the cuticle and true fkin.
Liquor of dropfy.—This liquid is of a yeliowifh green
colour, has fometimes confiderable tranfparency, but is
fometimes turbid. In its chemical properties it feems
to correfpond with the ferum of the blood.
Liquor of blifers.—The liquor which is fecreted by
the adHon of bliffers is ufually tranfparent. The con¬
flituent paits are the fame as thofe of the ferum of the
blood. Two hundred parts of this liquid yielded
Albumen, 36
Muriate of foda, 4
Carbonate of foda, 2
Phofphate of lime, 2
Water, 156
* Ann. dt
Chim. xiv.
a ay.
2765
Adtion of
heat.
2766
Of air and
acids.
200 *
P«j\—What is called healthy pus is about the con¬
fidence of cream, and of a yellowifh-white colour, an in-
fipid tade, and w7hen it is cold, without fmell. It pro¬
duces no change on vegetable blues.
2. When pus is expofed to a moderate heat, it dries,
and affumes the appearance of horn. By didillation it
gives out water in confiderable proportion, ammonia
and fome gafeous fubflance and an empyreumatic oil; a
fliining coaly matter remains behind, the adies of w7hich,
after being burnt, afforded fome traces of iron.
3. When this liquid is expofed to the air, it becomes
acid. It is foluble in fulphuric acid, forming with it
a purple-coloured folution. With the addition of wa¬
ter the pus feparates, and the dark colour difappears.
With concentrated nitric acid it forms a yellow co-
s T R Y.
759
loured folutxon, which effervefces during the combina-Component
tion. Water produces a precipitate. Pus is alfo foluble *>ar.ts
in muriatic acid, and is feparated by means of water.
Pus is not foluble in alcohol, but is thickened; nor is it — w «
foluble in the oils.
4. A whitiAx ropy fluid is formed by the addition Alkalies,
of a folution of the fixed alkalies, and by adding wa¬
ter the pus is precipitated. Pui'e ammonia forms with
pus a tranfparent jelly, and diflblves it in confiderable
proportion. _ _ ^
5. A precipitate is occafioned by means of nitrate Metallic
of fxlver, and it is ftill more copious with nitrate andfalts.
and oxymuriate of mercury.
6. The following lefts have been given to diftinguilhTo diftin-
pus from mucus, w-hich is of confiderable importance Pus*
in cafes w'here the formation of pus is fufpe&ed in
the lungs.
1. Pus is foluble in fulphuric acid, and precipitated
by w’ater. Mucus fwims. 2. Pus may be diffufed
th rough water, diluted fulphuric acid, and brine ; but
mucus is not. 3. Pus is fbluble in alkaline folutions,
and is precipitated by water; but this is not the cafe
with mucus. 2770
7. Thefe are the properties of pus when it is fecreted yaries in
from a fore which is faid to be in good condition, or inltsProPer-
a difpofition to heal. Its properties are very different
in what are called ill-conditioned fores. In thefe cafes
the matter fecreted is thin, fetid, and acrid. Matter
fecreted by cancerous fores, which has been examined,
converts the fyrup of violets to a green colour, and
from this matter fulphurated hydrogen gas is feparated
by means of fulphuric acid. This gas is fuppofed to-
exift in combination with ammonia.
Subdivifion III. Of the Solid Parts of Animals.
277I
The following are the folid parts of animals, wrhich Enumera^
we {hall treat of in the order in which they are enume-tion.
rated.
1. Bones,
2. Skin,
3. Mufcles,
4. Cartilage, tendons, &c.
5. Brain and neives,
6. Hair and nails,
7. Morbid concretions.
I. Of the Bones.
1. The bones are thofe parts of animals which give Of diff^renis
firmnefs, ftrength, and ftiape to the body. Bones aredenfity.
very different with regard to folidity and denfity, not
only in different parts of the body, but even in the fame
bone. The fpecific gravity, therefore, of bones, muft
be various. They are of a white colour, of a lamel-
lated ftrudfure, and inflexible. ^
2. When bones are burnt, they are converted intoA&ionof
a white, porous, inftpid fubftance, which ftill retains thereat,
flxape of the bone.
3. When bones are broken into fmall pieces, andc;0ntanm-
boiled in water, a confiderable quantity of fat rifes to fat.
the furface ; an oily matter, therefore, is one of the
conftituent parts of bones.
4. If the boiling be continued for a greater length of Gelatine,
time, the water diffolves another fubftance, which be¬
ing concentrated and left at reft, affumes a gelatinous
form.
■6o
G H E M
Eones, tlierefore, contain a portion of gela-
I S T R y.
Stibftances.
*^76
.Cartilage,
Component form.
Parts of jjne>
5. If bone is kept for fome time in diluted muria¬
tic acid, it is converted into a white flexible fubftance,
which retains the fhape of the bone. It becomes brit¬
tle and femitranfparent when dried ; it is foluble in
nitric acid, and when this acid is diluted, it is convert¬
ed by its aftion into gelatine. It forms a foap with the
fixed alkalies. From thefe properties it refembles
coagulated albumen. This fubftance, which is called
cartilage, is the firft part of the bone which is form¬
ed.
6. Befides thefe fubftances, bones contain a con-
fiderable proportion of earthy falts. Thefe are phof-
phate of lime, which is in great’proportion ; carbonate
of lime in fmaller proportion, with a ftill fmaller of
fulphate of lime.
7. The component parts of bones, therefore, are
earthy falts, cartilage, gelatine, and fat. The follow¬
ing table exhibits the proportion of thefe conftituent
parts in the bones of different animals. It was drawn
# ^ up by Merat-Gurllot. A hundred parts of bone were
Ch'un employed, and as much dried as poflible, and to this
xxxiy. 71. quantity the proportions fpecified refer *.
2777
Salts.
2778
Compofi
tion.
Names.
Human bones ta-T
ken from a bury- >
ing ground. j
Human bones dried \
but not buried. 3
Bones of the ox
 calf
 horfe
 ftieep
 elk
 hog
 hare
 pullet
 pike
■  carp
Phof-
Gelatine. phate of
lime.
16.
23-
3-
25-
9-
16.
17.82
9.0
6.0
12.0
6.0
Carbo¬
nate of
lime.
Lofs.
67
93
54
67-5
70.0
90.0
52.0
80.5
72.0
64.0
45.0
1.25
°*5
1.0
1.0
1.0
I,5
t.o
0.5
15-5
2
21
22.25
7-5
3°.°
5.0
20.5
23.0
48.5
2779
Of teeth.
8. The human teeth have been analyzed by Mr
Pepys, and he found the conftituents of different
teeth, and different parts of the teeth, to be the fol¬
lowing.
Phofphate of lime
Carbonate of lime
Cartilage
Lofs
Teeth of
adults.
64
6
20
10
100
Shedding
teeth of
children.
63
6
20
12
ICO
Roots of
the teeth.
58
4
28
10
100
He found the following to be the component parts
of the enamel of the teeth.
Phofphate of lime 78
Carbonate of lime 6
Lofs and water 16
ComjTor.ent
Parts of
Animal
Subftances.
IOO
But according to Fourcroy and Vauquelin the en¬
amel is compofed of
Phofphate of lime 72.9
Gelatine and water 27.1
100.0
II. Of the Skin.
1. The fkin, which forms the external covering of ConlHts^of
animals, conftfts of three parts; the epidermis or cu- three parts,
tide, the true fkin, and a foft fubftance called the
rete tniicofumy which lies between the cuticle and true
fkIn- . . . 2781
2. The epidermis, which may be feparated from the Epidermis,
cutis, by macerating the fkin in hot water, is a thin
elaftic fubftance, which is infoluble in water and in
akohol. ... 2782
3. Sulphuric and muriatic acids have little a&ion A&ion of
for fome time on this fubftance ; but it is immediately ac'ds> Re¬
converted into a yellow colour by means of nitric acid,
and at laft entirely decompofed. It is entirely foluble
in the cauftic fixed alkalies. From thefe properties the
epidermis is fuppofed to be coagulated albumen in a pe¬
culiar ftate of modification.
4. The cutis or true fkin is- denfer and thicker. QuiZ8,3
When it is heated, it firft contradls, then fwells up, ex¬
haling a fetid odour, and leaving behind a denfe mafs
of charcoal. By diftillation the fame products are ob¬
tained as from fibrina.
5. The fkin is foftened by rveak acids, is rendered Adtion of
tranfparent, and is at laft diffolved. It is converted acids,
into oxalic acid and fat by nitric acid, wfith the evo¬
lution of azotic gas and pruflic acid. It is converted
by means of the concentrated alkalies into oil and
ammonia. 2^g„
, 6. After maceration for fome time in water, a fmall Contains
proportion of gelatine may be obtained, by evapora-gelatine,
ting the water j but if the fkin be boiled for a confi-
derable time in water, it is entirely diffolved, and the
liquid, by evaporation, affumes the confiftence of jel¬
ly. The fkin is thus converted into glue. It is from
the fkins of animals that glue is chiefly extra&edj
and it is obtained of different degrees of ftrength from
the fkins of different animals. 2786
7. As fkin confifts chiefly of gelatine, it combines Tanning,
readily with tan. This compound forms leather ; and
the procefs by w'hich it is effedfted is called tanning, for
the detail of which fee the article Tanning.
8. The mucous fubftance, or rete mucofum, lies be- Ret2e mu-
tween the epidermis and true fkin. It is this which cofum.
gives the black colour to the fkins of negroes. It is
deprived of its colour, even in the living body, by
means of oxymuriatic acid. The foot of a negro be¬
came nearly white by being kept for fome time in wa¬
ter impregnated with this acid. The black colour,
however, returned in a few days.
III. Of
CHEMISTRY.
Component
Parts ot
Animal
Subftances.
761
III. Of the Mufcles.
a788
Strudture.
2789
A6Hon of
479®
Boiling.
I. The mufcular, or flefhy parts of animals, are of
a reddifli-white colour, and fibrous ftrufture. If a
quantity of mufcular fubftance is feparated into fmall
pieces, it becomes white. If the water be heated,
it coagulates. Albumen and a portion of fibrina are
obtained. It becomes gelatinous by farther evapora-
cold water, tion ; and, when the procefs is carried on to drynefs, and
alcohol added, a peculiar matter is diffolved ; which,
after the alcohol is expelled by heat, appears of a red-
dith brown colour, has an aromatic fmell, and a very
acrid taftej and it is foluble both in water and alco¬
hol. The gelatine formed in the mafs evaporated to
drynefs, with a little phofphate of foda and ammonia,
remains undiflblved by the alcohol. When this ex-
traftive matter is diftilled, it affords an acid, which is
combined with ammonia.
By boiling the fame mufcular matter for fome time
in.w^ater, another portion of albumen is obtained j and,
when the w’ater is concentrated by evaporation it is
converted into a jelly j and by treating with alcohol
as before, after evaporating to drynefs, the extra&ive
matter is taken up, and the gelatine and phofphoric
falts remain undiffolved. The fibres of the mufcle
are then of a gray colour, infoluble in w7ater, and be¬
come brittle when dry. This fubftance is fibrina,
which conftitutes the chief part of mufcular matter.
Nitric acid. ^ ^ naufcular matter be diffolved in nitric acid, and
ammonia added to the foliation, a precipitate of phof¬
phate of lime is obtained $ but no phofphate of lime
is obtained, when treated in this way, after being long
boiled in wrater, for it is either combined with the ge¬
latine, or is thus rendered foluble. Carbonate of lime,
however, is found after boiling the mufcular fub¬
ftance, and is converted into oxalate of lime by means
of nitric acid.
3. The conftituent parts of mufcular matter are the
following :
Phofphate of foda,
Phofphate of ammonia,
Phofphate of lime,
Carbonate of lime.
279*
Compofi-
tion.
2793
Properties
Fibrina,
Albumen,
Gelatine,
Exti'a&ive,
^ j- j, -t* Trom the difference of folubility of the fubftan-
matterfor^ Ces enter into the compofition of mufcular mat-
food. ter, and the different effefts of heat on thefe fubftan-
ces, the fenfible qualities at leaft muft vary confidera-
bly, according to the manner in w'hich this matter is
prepared for food. Accordingly, when the flefh of
animals is boiled, thole parts which are foluble in wa¬
ter, combine with it. Thefe are, the gelatine, the
extradive matter, and part of the faline bodies. It is
to thefe that the nutritious property of foups is afcrib-
ed. But when the flefti of animals is roafted, it has a
much higher flavour, in confequence of thefe fubftan-
ces not being feparated from it, and particularly the
extradive matter, on which the odour and flavour de¬
pend. This extradive matter, according to Fourcroy,
compofes the browm cruft which is formed on flefti du¬
ring its roafting.
5. The mufcular pai't of different animals, from its
properties, fenfible qualities at leaft, feems to poffefs very differ¬
ent properties. Hence the difference in the tafte, fla-
Vol, V. Part II.
4794
Boiled.
2795
Roafted.
4796
Different
vour, and nutritious quality, of the flefti of different Component
animals. Animal
6. When the mufcular parts of animals are expofed Supp-ances.
for a confiderable length of time to the adion of run-1—.v-.i j
ning water, they are converted into a peculiar fub-
ftance, refembling in fome meafure fpermaceti. The Converiion
fame change indeed, in fimilar circumftances, takes of mufcular
place on the other foft parts of animals. This was firfl matter into
obferved in the year 1786, in the Innocents burying- *
ground in Paris, where great numbers of bodies were
thrown together into the fame pit. The time which
was required for this converfion was fuppofed to be in
general about thirty years. But it has fince been
found, that animal matters are converted into a fub¬
ftance exadly fimilar, and in a much ftaorter period,
by expofing them to the adion of running water. .
7. The matter produced by this change is of a pro.)erties,
white colour, foft and unduous to the feel, and melts
like tallow. It is decompofed by diluted acids, and
an oily matter, with which it is mixed, is feparated.
By the adion of alkalies and lime, ammonia is evolv¬
ed. By expofure to the air, it is deprived of its white
colour ; the ammonia is almoft entirely carried off,
and a fubftance refembling wax remains behind. The
oily matter which is feparated by a diluted acid, is of
a white colour and concrete. It becomes of a grayifti
brown colour by drying, and affumes a cryftalline, la-
mellated texture, like fpermaceti. At the tempera¬
ture of 126° it melts. It is foluble in alcohol at the
temperature of 120m. It forms a foap with alkalies,
and burns like oil 5 but exhales a difagreeable odour,
which is the chief objedion to its ufe as a fubftitute
for oil, as it is fuppofed it may be obtained at a cheap¬
er rate. A manufadure indeed has been eftablifhed
at Briftol for the preparation of this fubftance.
IV. Of Membranes, Tendons, and Ligaments.
1. Membranes are thofe parts of the body which in- Membrane*
elude fome of the internal parts of animals. Many
of them are extremely thin, and they poffefs different
degrees of tranfparency. They become pulpy by ma¬
ceration in water, and by boiling are almoft entirely
converted into gelatine, fo that they are chiefly com-
pofed of this fubrtance. No phofphate of lime or other
faline matter has been deteded in the membranous
fubftances hitherto analyzed. 2g0#
2. Tendons are reduced by boiling to a gelatinous Tendons,
fubftance, fo that they are compofed of a fimilar mat¬
ter with membranes.
3. The ligaments afford a portion of gelatine by Ligaments,
boiling, but are not, like the two former, entirely re¬
duced to jelly, fo that fome other fubftance befides
gelatine enters into the compofttion of ligaments.
V. Of the Brain and Nerves.
I. The matter of the brain and nerves has a foft,
foapy feel, and a clofe texture. When expofed to the water See.
air at the temperature of 6o°, it foon becomes putrid,
exhaling an offenfive fmell, and giving out a confider¬
able quantity of ammonia. It is not foluble in cold
water; but triturated with water in a mortar, a part is
diffolved, and if this be heated moderately, it coagu¬
lates. If fulphuric acid be added to this folution,
white flakes appear on the furface, and the liquid af-
5 D fumes
76:
CHEMISTRY.
4803
Sulphuric
acid.
2804
’Nitric acid
Component fumes a red colour. Similar flakes are produced by
Parts of t}le aftion of nitric acid, but the colour of the liquid
Subftances yell°w* nitric acid be added till a flight acidity
1 - t 1 is produced, a coagulum of a white colour feparates,
which is infoluble in water and alcohol, is foftened by
heat, and becomes tranfparent when it is dried. This
matter, therefore, pofleffes many of the properties of
albumen.
2. If a quantity of brain be triturated with diluted
fulphuric acid, part is diflblved, and part is coagulat¬
ed. The liquid part is colourlefs, and when it is eva¬
porated, it becomes black, while fulphurous acid is
exhaled, and cryftals are formed. When it is evapo¬
rated to drynefs, a black mafs remains behind. By di¬
luting this with water, charcoal feparates. The mat¬
ter therefore is entirely decompofed, ammonia is dif-
engaged, and combines with the acid, forming ful-
phate of ammonia. By evaporating the water, ful-
phate of ammonia and fulphate of lime, phofphoric
acid, and phofphates of foda and ammonia are obtain¬
ed ; and thefe falts may be feparated by means of al¬
cohol. Thefe falts, however, exift in brain in fmall
proportion. By treating in the fame wTay a quantity
of brain with nitric acid, part is diflblved, and part
coagulated. When the folution, wdnch is tranfparent,
is evaporated till the acid is concentrated, carbonic
acid and nitrous gafes are evolved 5 a great quantity
of ammonia is feparated with eflervefcence, and char¬
coal remains behind, mixed with oxalic acid.
3. If a quantity of brain be evaporated to drynefs
with a gentle heat, a portion of tranfparent liquid fe¬
parates, and the refiduum affumes a brown colour when
it is dried. The weight of this refiduum does not ex¬
ceed one-fourth of the quantity employed. If the re¬
fiduum be repeatedly boiled wuth alcohol, more than
one-half is diflblved •, and when the alcohol cools, it
depofits a yellowifh white fubllance in the form of
fhining plates, which may be reduced to a kind of
dudlile pafte. It becomes foft with the heat of boil¬
ing water, and blackens with an increafe of tempera¬
ture, exhaling empyreumatic and ammoniacal fumes;
a charred matter remains behind. By evaporat¬
ing the alcohol, a yellowifh black matter is depofited,
which reddens paper ftained with turnfole.
4. Brain is foluble in concentrated cauftic potafli;
and during the folution, a great quantity of ammonia
is given out.
a 805
Of heat.
s8o6
Alkalies.
2807
VI. Of Hair and Nails.
Different in I. If we include all thofe fubftances which form the
appearance, covering of animals, as briftle, hair, wool, and down,
under the general name of hair, and particularly as’
they poflefs nearly the fame properties, we fliall find
that it varies, greatly in fize, in length, and colour,
m different animals, and even in different parts of the
2808 fr°dy the fame animal.
Action of . 2* hair be boiled in water, a quantity of gelatine
water. is obtained, and by continuing the boiling, the hair
becomes fo brittle, that it crumbles to pieces. The
part which remains, after the gelatine has been fepa¬
rated, feems to be coagulated albumen. But befides
gelatine and albumen, it appears from the combuftion
of hair, that it contains a portion of oily matter# Ber-
thollet obtained by the diftillation of a quantity of
hair, carbonate of ammonia, water having the fmell Component
of burnt hair, fome oil, and elaftic fluids which were ^arts
probably carbonated hydrogen and carbonic acid ga-Sub^‘a^es>
fes. The oil was of a brownifh colour, and was con v
Crete in the ordinary temperature of the atmofphere. 2g
It was foluble in alcohol, and burnt with a vivid Diftillation;.
flame. The charcoal which remained could fcarcely
be calcined, but fome of its particles were attradled
by the magnet. 2810
3. The acids foften and deftroy the colour of hair. Acids.
It is decompofed by fulphuric acid with the afliftance
of heat ; charcoal is depofited, and carbonic acid gas
given out. Nitric acid communicates a yellow colour
to hair, and diflblves it with the aid of heat. An
unctuous matter is feparated, and oxalic acid is form¬
ed. Muriatic acid at firft whitens hair ; but it be¬
comes yellow when it dries. Oxymuriatic acid alfo
bleaches hair ; but at the fame time deftroys its tex¬
ture. It is converted into a pulp when it is introdu¬
ced into oxymuriatic acid gas. ^
4. Hair is foluble in the alkalies, and is converted ^j^alies.
into a reddifh-coloured foap, with the evolution of am¬
monia. If muriatic acid be added to the folution of
hair in potafh, fulphurated hydrogen gas is evolved,
from which it appears that hair contains fulphur. Silver
is blackened by the fame folution. 2812
5. The metallic oxides alfo have the eflefl of black-Metallic
ening hair. It is in this way that the hair isox^es*
dyed black. The red oxide of lead, the acetate of
lead, and fometimes even the nitrate of lead, and the
nitrates of mercury and filver, are employed for this
purpofe. _ _ 2813
Nai/s.—The nails are confidered as an elongation Nails,
of the epidermis. They are attached to it, and fepa-
rate when it is removed. They become foft by long
maceration in water. There is no precipitate formed
in this folution with tan. Nails are foluble in the
acids and the alkalies. They are ftained with metal¬
lic oxides, and combine with colouring matters.
From thefe properties the nails are confidered as a kind
of coagulated albumen, with a fmall proportion of
phofphate of lime, and according to fome, carbonate 2814
of lime. Compofi-
tion.
' VII. Of Morbid Concretions.
2815
I. Earthy matters are frequently found in different Found in
parts of animal bodies, which are to be confidered as^‘ffererit;
extraneous, and occafioning, at leaft in the human j:>aijts ^
body, fome of the fevereft diforders to which it is fub-
jecl. Thefe earthy matters are generally combined
with an acid, and in fome cafes entirely compofed
of an acid. Thefe fubftances, which have been
called concretions, and calculi, are formed, fometimes
in the folid parts of the body, but chiefly among the
fluids. jjg!#
Pineal concretions.^—-Phek concretions are almoft Pineal,
always found in the pineal gland of the human brain.
They are indeed fo rarely wanting in the brain, that
they are confidered as natural, as they do not feem to
produce any inconvenience or difeafe. They have
been found to confift of phofphate of lime, mixed with
fome animal matter.
2817
Salivary concretions.—Concretions form in the fali-Salivary,
vary glands, and in the dufts which convey the fecret-
ed
Component
Parts of
Animal
Subftances.
2818
Tartar of
the teeth.
2819
Pulmonary.
2820
Inteftinal.
aSat
Cornpofi-
* Ann. dc
Cbim.
Xxiii. 130.
282a
Biliary
eompofed.
2823
Of infpif-
fated bile.
2824
Of a fub-
ftanee like
fpermaceti.
2825
Of Hiining
plates.
2826
-Or mixed.
G H E M
ed fluid from thefe glands to the mouth. The com¬
ponent parts of thefe concretions have been found to
be alfo phofphate of lime and animal mucilage.
The tartar of the teeth is compofed of the fame fub-
ftance. When this was examined with the microfcope,
it feemed to be compofed of fmall fhining grains unit¬
ed to each other, and containing a great number of
pores or fmall angular cavities, refembling the cells of
polypi, on account of which feme naturalifls have
aferibed its formation to infefts j but it is more natural
to fuppofe, that it is a cryrtalline arrangement of the
faline matter of which it is compofed.
Concretions have alfo been found in the pancreas,
and its duffs, and are fuppofed to confift of the fame
materials.
Pulmonary concretions.—Thefe concretions are form¬
ed in the lungs during afthmatic and phthifical dif-
orders. They are fmall hard bodies, unequal and
rough, of a gray or reddilh colour, which become
wdiite as they dry in the air. They are alfo compofed
of phofphate of lime mixed with animal matter.
Intejlinal concretions.—Thefe are more rarely met
with in the human body. When they are found, they
have been generally formed on the ftones of fruits, or
fome other hard body which has been fwallowed.
They are more frequent in the inteftines of the inferior
animals, as in thofe of the horfe. Some that have been
examined were of a gray colour, and of a radiated or
cryftallized ftruflure. The component parts of a
Hone of this defeription, analyzed by Berthollet, v’ere
the following.
Magnefia
Phofphoric acid
Ammonia
Water
Animal matter
18.0
26.0
3*2
46.0
4.0
97.2
Biliary concretions.—Biliary concretions, or calculi,
are formed, either in the liver itfelf, in the gall-blad¬
der or in the gall duffs, hence they have alfo been
called gall-Jlones. Some found in the liver itfelf, are
compofed of phofphate of lime combined with fome
animal matter. The calculi which have been found
in the gall bladder, are different, both in ftruflure
and compofition. Some of them feem to be compofed
of concentric layers of infpiffated bile. Thefe have
different degrees of confidence 5 they are fometimes
friable, and of a brown or reddifh colour. The gall-
ftones of the ox, which are ufed by painters, are of this
kind. Another kind of biliary calculi differ only
from the former in having a fmooth, whitilh or gray-
ifh covering, refembling fpermaceti. They are fome¬
times found in confiderable numbers in the gall-blad¬
der.
A third fpecies is of a white or gray colour, opaque,
or femitranfparent. Thefe are compofed of fhining
cryftalline plates, or have a radiated ftru&ure. They
are frequently folitary, and are then about the fize,
and have the form of a pigeon’s egg. The nucleus
of this kind of gall-ftone is compofed of infpifftted bile.
A fourth fpecies is compofed of different proportions
of the fpermaceti fubflance and the concrete bile.
Thefe are the moft frequent of all the kinds of gall-
I S T R Y. 763
ftones, and are alfo the moft numerous. They are of Component
a deep green or olive colour. Sometimes they exhi- ^-tS
bit internally, fmall fliining plates of a deep yellow Subftan(ies>
colour. —y——<
All thefe calculi are foluble in the cauftic alkalies, 3827
in folutions of foap, in fixed and volatile oils, in alco-A&ion of
hoi, and partially in ether. alkalies,
1. Urinary concretions.—Thefe concretions which&c*
are frequently formed in the urinary bladder of man, 2828
and produce one of the moft excruciating diforders
which he is fubjett, have long attradled attention, 1L
with a view’ to prevent their formation, or to effedfc
their diffolution after they have been formed. Little,
however, has yet been done, to accomplilh either of
thefe ends j but the nature of the concretions them-
felves has been carefully inveftigated, and their com¬
ponent parts minutely examined by different chemifts.
Among thefe the labours of Fourcroy and Vauquelin
are not the leaft confpicuous. Urinary calculi are Found in
found, either in the kidneys, the ureters, or the uri-different
nary bladder itfelf. Calculi, as found in the kidneys, ^
vary confiderably in fize, form, colour, and inter-01 &anS'
nal ftru&ure. They are ufually fmall, round, con¬
crete bodies, fmooth and Ihining externally, of a red-
difh-yellovv colour, and fo hard as to be fufceptible
of a polilh. They pafs readily along the ureters to
the bladder, and from thence are ejefted along with
the urine. It is the formation of thefe fmall concre¬
tions which conftitutes the difeafe called gravel.
Some of thefe concretions fometimes remain in the
kidneys, and increafing in volume by receiving new
additions of matter, form large calculi. This happens,
however, but rarely. The calculi which have been
found in the ureters, have originated from the kidneys,
and being too large to pafs along the ureters, receive
new additions of matter as it is depofited from the
urine, and enlarge in fize, at the fame time dilating
the ureter.
But by far the moft common are thofe which are
found in the bladder itfelf. Thefe calculi have either
originated from fmall concretions formed in the kid¬
neys, and thefe pafling along the ureters into the blad¬
der, form a nucleus on which fucceflive layers of mat¬
ter are depofited from the urine *, or they have their
origin and complete formation in the bladder itfelf, or
have been formed on fome extraneous fubftance intro¬
duced into the bladder through the urethra. The firft
are the moft frequent. 2g^0
2. The form of urinary calculi is various, but they Phyfical
are frequently of a fpheroidal or egg-ftiape, or compref-properties,
fed on two fides. Sometimes they are polygonal, wrhich
happens when there are feveral in the bladder at the
fame time. Some have been found of nearly a cubical
form. Their extremities are frequently either pointed or
obtufe. Their fize is extremely various. Sometimes
they are not larger than fmall beans, while fome have
been of fuch an extraordinary fize as to fill the bladder
itfelf’, but they are moft frequently from the fize of a
pigeon’s egg, to that of a hen’s egg. Some are of a
yellowifti-brown colour, refembling wrood. Thefe are
compofed of uric acid. Thofe which are white, or
grayifh-white, confirt of the earthy phofphates, and thofe
which are of a deep gray or blackifti colour, are com¬
pofed of oxalate of lime. Some exhibit all thefe dif¬
ferent fhades mixed together. The furface of urinary
5 D 2 calculi
764
C H E M
Component calculi is fometimes fmbdth and poliflied ; fometimes it is
Parts ot roUg}i and unequal, and tuberculated. Some urinary
calculi having their furface mamellated, are called
mulberry Jlones, from fome refemblance to a clufter of
mulberries. Some of the white calculi are foft and
fmooth, femitranfparent, and covered with Ihining cryf-
tals. The fpecific gravity varies from J.213 to 1.976.
The odour of urinary calculi is fometimes perceptibly
urinous and ammoniacal, which is difcovered by rafp-
ing or fawing them ; fometimes it is faint and earthy,
as in the white calculi; and fometimes it refembles that
of ivory fawed or rafped, and is analogous to the odour
of femen. Mulberry calculi are diitinguilhed by this
odour.
3. The following fubftances have been difcovered in
urinary calculi.
*831
Conftituent
parts.
Oxalate of lime,
Carbonate of lime,
Silica,
Animal matter.
2832
acid.
2833
Urate of
ammonia.
2834
Jhoiphate
lime.
283S
s)! ammo¬
nia.
2836
Oxalate of
lime.
Uric acid,
Urate of ammonia,
Phofphate of lime,
Phofphate of magnefia and
ammonia,
Uric acid exifts in almoft all urinary calculi. Many
calculi indeed are entirely formed of it; but it is found
in greater or fmaller proportion, in almofl all that have
been analyzed. The nature and properties of this acid
have been already defcribed. The calculi compofed
of it are of a brown colour, are fmooth and polifhed,
and have the appearance of wood. When this fub-
flance is triturated with a concentrated folution of pot-
afh or foda, it forms a thick faponaceous matter, which
is precipitated by diluted acids. It is dilTolved by ni¬
tric acid, and is converted into a red colour. This acid
is a compound of azote, carbone, hydrogen, and oxy¬
gen ; and when decompofed by chemical agents, it is
converted into ammonia, malic, oxalic, pruffic, and car¬
bonic acids.
Urate of ammonia, the next fubflance found in uri-
nary calculi, is alfo foluble in potafh and foda, but the
folution is accompanied with a copious evolution of
ammonia. Calculi compofed of this fubftance, confift
of thin layers, and are not always fmooth. They are
generally ot a fmall fize, and referable an infufion of
coftee. The earthy phofphates are frequently interpof-
cd between the layers of calculi compofed of this fub-
ilance, and it is often mixed with phofphate of ammonia
and magnefia.
Phofphate of lime frequently enters into the compo-
fition of calculi. It is ufually in thin layers, which are
friable, and have little confiftency. They are of a
grayifh-white colour, and opaque, without tafte or
ime!l; The phofphate of lime is ufually mixed with
gelatinous matter ; is foluble in different acids, and is
precipitated by the alkalies. Some calculi have been
difcovered entirely compofed of phofphate of lime.
Phoiphate of ammonia and magnefia is in the form
of white, femitranfparent iayers, and it is fometimes found
cryftaltized on the furface of calculi in the form of
pnfrns. \\ hen U is reduced to powder it is of a bril-
hant white very foluble in diluted acids, and is decom¬
pofed by the hxed alkalies.
Oxalate of lime is ufually mixed with phofphate of
lime and uric acid, but fometimes it is combined only
with animal matter in mulberry calculi. The calculi
compofed of it are of a dark green colour, and extremely
I S T R Y.
hard. It diflblves with difficulty in diluted nitric Component
acid, and is decompofed by the carbonates of potafir i>arts °1
and foda. Animal
The carbonate of lime conftitutes the greateft part^H^^l!^
of fome urinary calculi.
Silica has been rarely found in calculous concre- Carbonlte
tions. It was detefted mixed with phofphate of lime, of lime,
only in two mulberry calculi, which were extremely 2S38
hard. Silica.
In all calculous concretions there is a quantity of 2839
animal matter, wffiich unites or cements together the Amhnal
layers or particles of the hard fubftances of which theymatter*
are compofed. This animal matter feems to poflefs the
properties of albumen. Sometimes it feems to be com¬
pofed of albumen mixed with urea, of coagulated al¬
bumen, or gelatine. aS40
4. I'ourcroy and Vauquelin have analyzed more then divided in-
600 calculi, and by comparing the properties of each,t0 t*iree
they have arranged them into three genera and 12 fpe-genfereacand
cies. The firft genus comprehends thofe fpecies which
are compofed of one fubftance. Thefe are the three
following :
1. Uric acid,
2. Urate of ammonia,
3. Oxalate of lime.
The fecond genus includes thofe fpecies which are
compofed of two fubftances. It confifts of the follow¬
ing feven fpecies :
1. Uric acid and the earthy phofphates, in diftinft
layers.
2. Uric acid and the earthy phofphates intimately
mixed together.
3. Urate of ammonia, and the phofphates in diftindh
layers.
4. The two preceding intimately mixed.
5. Earthy phofphates mixed or in thin layers.
6. Oxalate of lime and uric acid in layers.
7. Oxalate of lime and earthy phofphates in layers.
The third genus confifts of two fpecies, which are
compofed of three or four fubftances.
1. Uric acid or urate of ammonia, earthy phofphates
and oxalate of lime.
2. Uric acid, urate of ammonia, earthy phofphates,.
and filica.
_ We fhall now ftate the general charafters of thefe
different fpecies.
Genus I.
Species 1. Uric acid.— Fhefe calculi are eafily known
by their colour, which refembles wood. It is reddifti,
or yellowifti. I hey are of a radiated, denfe, fine texture,
completely foluble in pure alkalies, without emitting any
odour. I hey vary greatly in fize, and have generally
a fmooth poliftied iurface. The fpecific gravity is from
1.276 to 1.786. It ufually exceeds 1.5. Of 600 cal¬
culi which were analyzed by Fourcroy and Vauquelin,
150 confifted of pure uric acid. The fand or gravel
which is formed in the kidneys, ufually belongs to this
fpecies.
2. Urate of ammonia.—Calculi compofed of this fub¬
ftance, are ufually of fmall fize, foluble in cauftic fixed
alkalies, with the evolution of ammonia, of the colour.
of
C H E M
Component of the infufion of coffee, and are compofed of fine lay-
Partsof ers which are eafily f’eparated. The 1'urface is com-
Ammal moniy fmooth, and foraetiraes finning and cryftalline.
^ I he Ipecmc gravity is from 1.225 to !-720. They
are foluble in hot water, at lead: when reduced to
powder. The external layer is fometimes pure uric
acid. This fpecies is rare.
Oxalate of lime.—This fpecies is eafily recognized
by its rough, mamellated furface, from which thofe cal¬
culi have received the name of mulberry flones. The
colour is browm, they are of a clofe hard texture, and
when rafped or fawed, emit the odour of femen. They
are foluble with difficulty in acids, and are infoluble in
the pure alkalies. The fpecific gravity is from 1.428
to 1.976. This fpecies frequently conftitutes the nu¬
cleus of other calculi.
Genus II.
Species 1. Uric acid and earthy phofjbhates in difinEi
layers.—This fpecies is known by its furface, which is
white like chalk, friable and femitranfparent. The
external layer is compofed of the phofphate of lime,
or of ammonia and magnefia. The nucleus confills of
uric acid, and when the calculus of this fpecies is fawed
afunder, two fubllances of which it is compofed are
didin&ly feen. It is indeed only then that the fpecies
can be recognifed. Calculi of this defcription are not
uncommon, and they are generally of the largeft fize
of all the urinary calculi. The fpecific gravity is very
variable.
2. Uric acid and earthy phofphates intimately mixed.
—- This fpecies contains numerous varieties, from the
different proportion of the conftituent parts. Some¬
times the uric acid and the earthy phofphates are ar¬
ranged in layers fo thin, that they are fcarcely percep¬
tible. Sometimes they are fo mix d together that they
can only be dete&ed by analyfis. But fometimes the
layers are fufficiently diftinft. The fpecific gravity is
from 1.213 to 1.739- This fpecies or calculus is com¬
mon.
3. Urate of ammonia and the phofphates in difinEi
layers—In this fpecies the nucleus confifts of urate of
ammonia ; and the external layers are moll frequently
compofed of the earthy phofphates mixed together, or
more rarely of phofphate of ammonia and magnefia.
This fpecies is ufually of fmall fize •, its fpecific gravity
is from 1.312 to 1.761. It is not very common.
4. Urate of ammonia and earthy phofphates mixed. 
The calculi belonging to this fpecies are very rare.
They are of a pale-yellow colour, and of lefs fpecific
gravity than the fecond fpecies of this genus, which
they referable in external characters. When they are
treated with potaffi, ammonia is difengaged. This fpe¬
cies is ufually of fmall fize.
5. Earthy phofphates mixed, or in thin layers.—This
fpecies is diflinguiffied by its pure white colour. They
are of a friable texture, infoluble in alkalies, and fo¬
luble in diluted acids. This fpecies is pretty common,
and often of a large fize. The concretions formed on
extraneous matters introduced through the urethra in¬
to the bladder, are of this kind. The fpecific gravity
varies from 1.138 to 1.471.
6. Oxalate of lime and uric acid in difinEi layers. 
In this fpecies the nucleus confiffs of oxalate of lime,
and it is covered with a layer of uric acid. From ex-
1 s t r y. 765
ternal appearance they are not diffinguifiied from thofe Component
entirely compoled of uric acid, till they are fawed a- ^ar.ts
funder. The fpecific gravity varies from 1.341 *0 SuMan^e?
I-754- ' ^ v—
7. Oxalate of lime and earthy phofphates in layers.—
The oxalate of lime conftitutes the nucleus, and the
earthy phofphates compofe the external covering in this
fpecies of calculus. It can only be diilinguiffied by
being fawn afunder. The calculi belonging to this
fpecies vary greatly in form and fize, but they are al¬
ways white externally. The fpecific gravity is from
1.168 to x.752.
Genus III.
Species 1. Uric acid, urate of ammonia, the earthy
phofphates and oxalate of lime.—In this fpecies there are
frequently three diftindt layers. The center or nucleus is
compofed of oxalate of lime 5 the next of uric acid or
urate of ammonia ; and the outermoft of the earthy phof¬
phates, which are ufually mixed with uric acid, or urate
of ammonia. The calculi of this fpecies can only be
diftinguilhed by fawing them in two. There are many
varieties of this fpecies, from the different propor¬
tions and the different arrangement of the conftituent
parts.
2. Uric acid, urate of ammonia, earthy phofphates, and
flica.—In the calculi belonging to this fpecies, the
filicafeems to hold the place of the oxalate of lime. It
is mixed with uric acid and urate of ammonia, and
covered with the phofphate of lime. This is the rareft
fpecies of all that have been examined. 2841
5. The inveftigation of the caufe of the formation Caufes of
of calculous concretions has occupied a great deal ofur^aryca^"'
the attention of phyftologifts and phyficians, and un-cu^’
doubtedly it is one of the moft important on which the
refearches of man can be employed ; for by obviating
the caufe of this diforder, its terrible effedls might be
prevented. Unfortunately, however, little is yet known
on this intricate fubjedl. In many cafes, indeed, the
formation of urinary calculi is obvioufly owing to the
introduftion of fome extraneous fubftance into the blad¬
der by the urethra. But this mode of formation is
comparatively rare, and the calculi thus formed are
compofed of the earthy phofphates, which are depoli-
ted from the urine. All urine contains uric acid.
1 his forms one of the moft common fpecies of calculi.
The particles of gravel which are formed in the kid¬
neys, confift of this acid, fothat it very often, forms the
nucleus of calculous concretions. But the production
of an exceffive quantity of uric acid, in whatever way
this takes place, feems to be the moft powerful caufe
of the production of urinary calculi. It has been ob-
ferved too, that the urine of thofe perfons in whom thefe
concretions are moft frequent, is loaded with an un-
ufual proportion of animal matter. This forms the ce¬
menting fubftance of thefe concretions. In the forma,
tion of thefe concretions it would appear that the dif¬
ferent fubftances of w-hich they are compofed, are fe-
creted at different times,or in differ-ent proportions, fince
the different fucceffive layers of calculi are compofed
of totally diftinft fubftances. It is perhaps difficult oc
impoffible to explain the formation of thofe calculi in
which oxalic acid is a conftituent part. This acid has
fcarcely ever been deteCled in the urine, at leaft of a.
dults, fo that it muft be produced by fome morbid ac.
tion.
766
CHEMISTRY.
Animal
Subftances.
2842
Solvents.
Component tion by which feme of the animal fluids are converted
Parts of jnto fubftance.
6. It has long been an obje£f with phyficians, to dif-
cover the means ofdiffolving thefe fubftances after they
have been formed ; and the empiric has not been idle
in offering his noftrums which are held out as lolvents
of the Hone, and which it is no wonder are eagerly re¬
ceived with the hope of relief from one of the mofl:
dreadful maladies which can afflidf mankind. Nothing,
however, can be done with this view on rational prin¬
ciples, without previoufly knowing the nature and pro¬
perties of the fubftances which are to be difiblved ; and
even when this is known, it muft appear, from confider-
ing the fundlion of digeftion, and the changes which
all fubftances taken into the ftomach, undergo, that
little can be expefled from the exhibition of remedies
in this way. After being fubjefted to the different
proceffes of digeftion, refpiration, and fecretion, the
properties of thefe fubftances are totally changed, fo
that they can only produce fome general effedt on the
fyftem, and can have no fpecific adlion on particular
organs. It has therefore been propofed by the French
chemifts, to employ thefe fubftances which poffefs the
property of diffolving urinary calculi out of the body,
by injedling them through the urethra into the blad¬
der.
It has been found by experiment, that calculi com-
pofed of uric acid, or urate of ammonia, are foluble in
folutions of pure potafh and foda, even when thefe folu-
tions are fo much diluted with water that they may be
taken internally, without producing any inconven¬
ience.
Experiments have alfo Ihewn, that calculi compofed
of the earthy phofphates are foluble in nitric and mu¬
riatic acids, fo much diluted that they may be taken in¬
ternally without the fmalleft injury.
Calculi compofed of oxalate of lime are lefs eafily dif-
folved. They, are, however, foluble in diluted folu¬
tions qf carbonate of potafli or foda.
The firft difficulty, however, which prefents itfelf in
the ufe of thefe folvents, is to difeover the nature and
compofition of the concretion to be diffolved. This can
only be done by employing fome of the folutions, and
examining them after they have remained for fome time,
or as long as they can be retained in the bladder. If
a weak folution of potaffi has been injefled, it is to
be filtered, as foon as it is thrown out ; and if on the ad¬
dition of a little diluted muriatic acid, or vinegar, a
white precipitate appears, the calculus istobe confidered
as compofed of uric acid. But if this folution has been
employed for fome time, and no precipitate is produ¬
ced in this way, the folution for the phofphates is then
to be employed, and when it is paffed, alter remaining
fome time in the bladder, a precipitate will be formed
with the addition of ammonia. rl his precipitate will
be phofphate of lime.
If no effedt is produced by any of thefe folutions,
and if the feverity of the fymptoms continues, there is’
fome probability that the calculus confifts of oxalate of
lime. This, it has been obferved, is the moft diffi¬
cult of folution. It may be diffolved, however, al¬
though flowly, in nitric acid greatly diluted with’wa¬
ter, or in w7eak folutions of the carbonates of potaflr
or foda. Thefe folutions, therefore, muft be employ¬
ed when the others have failed. The effeds of thefe
*843
Methods of
tiling.
folutions muft be judged of by the alleviation of the Component
fymptoms, or by the adual examination of the ftone ot
itfelf at different times, by means of the catheter,
found. Whatever folution is employed, it ought to ^< ^
be of the temperature of the body, and fo much di¬
luted as not to irritate or injure the internal furface of
the bladder to wffiich it is applied. Before the injec¬
tion is made, the urine fhould be evacuated, and the
injedion retained, for at leaft, a quarter of an hour,
from that to an hour, or as long as it can be done with¬
out inconvenience. The injedions fhould be repeated
at firft: three or four times a-day, and afterwards in-
creafed to fix or eight times. As calculous concre¬
tions are frequently leveral years in forming, it is ob¬
vious that they muft require a long time to diffolve
them, fo that the ufe of injedions, if any relief is to
be obtained from them, muft be long continued. a^44
7. Calculous concretions are not unfrequent in the a^imalT
urinary organs of other animals. They have been
found in the horfe, in the dog, the rabbit, the Hog,
and the rat. They are moft frequently compofed of
carbonate of lime with fome animal matter 5 fome-
times of phofphate of lime, of phofphate of ammonia,
and of carbonate of lime and phofphate of lime ; bnt
no traces of uric acid have yet been deteded in thefe
concretions. 2845
Gouty concretions.—1. Concretions, which are com-
monly called chalkJlones, are fometimes formed in the
joints of thofe who have been long fubjed to the gout.
They have been difeovered by chemical analyfis to be
compofed of uric acid and foda. 2846
2. Thefe concretions are of a wffiite colour, irregu-^roPert^e3*
lar in their form, and of a fine granulated texture.
When they are boiled for a few minutes, in 100 times
their w’eight of water, they are entirely diffolved.
Sulphuric acid added to this folution, produces a white
precipitate, which affumes the form of fmall needles,
which are cryftals of uric acid. The remaining li¬
quid, by being evaporated, affords fulphate of foda. 2847
3. By treating a quantity of gouty concretion with^p^0*
100 times its weight of a concentrated folution of 1'
potafh with the aid of heat, it is almoft entirely dif¬
folved, exhaling at the fame time the faint odour of
animal matter. When the liquid is filtered, and mu¬
riatic acid added, it produces a white precipitate,
which is uric acid. From this it appears, that gouty
concretions poffefs fimilar properties with thofe formed
in the urinary organs, excepting that they contain a
greater proportion of animal matter. 2848
4. When it is diffolved in a fmall quantity of dilut-Ac‘^s> &c*
ed nitric acid, it tinges the fkin w ith a role colour,
and wffien evaporated, leaves a rofe-coloured deliquef-
cent refiduum. By diftillation this fubftance yields
ammonia, pruflic acid, and an acid fublimate. ArUfic'^l
5. If a fmall portion of uric acid be triturated with forinat;on>
foda and a little warm water, they combine j and af¬
ter the fuperfluous alkali has been wafhed out, the re¬
mainder has all the chemical properties of gouty mat-*
ter *• Tranfl
Subdivifion IV. Of Subftances Peculiar to Different 33^
Animals.
Having briefly detailed the nature and properties of
thofe fubftances which are common to animals, we fhall
now take a general view of fome lubllances which are
peculiar
CHEMISTRY.
Comporent peculiar to different animals, and we (hall treat of
Parts of thefe according to the order in which they are arran-
sutZc's. g'd ■” natural hiftorr-
^ I. Of Subftances peculiar to the Clafs Mammalia.
The fubftances peculiar to this clafs of animals are
the following.
1. Ivory, 6. Civet,
2. Horn, 7. Caftor,
3. Hartlhorn, 8. Ambergris,
4. Wool, 9. Spermaceti,
5. Mulk, 10. Bezoards.
I. Ivory, which is the teeth of the elephant, is a
bony fubftance, of a fine compact texture, white co¬
lour, and fo hard as to be fufceptible of a fine polilh.
It is compofed, like the bones, of gelatinous matter and
phofphate of lime, and when it is diftilled it furnifhes
water, a thick oil, and carbonate of ammonia j and
when calcined to whitenefs, it leaves pure phofphate of
lime.
The component parts of ivory are, according to
Merat-Guillot, the following.
Phofphate of lime, 64.0
Carbonate of lime, c.i
Gelatine, 24.0
Lofs, 11.9
2850
Ivory.
2851
Horn.
100.0
2. Horn.—The fubflance called horn, poffeffes dif¬
ferent properties from that of bone. This matter is
produced in the horns of different animals, as thofe of
oxen, (beep, and goats. It has fome degree of tranfpa-
rency, and when heated it becomes fo foft and flexible,
that it may be made to affume different fhapes, and
formed into different inftruments and utenfils. Horn
yields a very fmall proportion of earthy matter. The
other conftituent parts feem to be coagulated albu¬
men and gelatine.
The following are the proportions of the conftitu-
ents of hartfhorn.
Phofphate of lime,
Carbonate of lime,
Gelatine,
Lofs,
57-5
x.o
27.0
H-5
is diftinguifhed by a ftrong aromatic fmell. It is par¬
tially foluble in water, to which it communicates the
odour. A fmall portion of it alio may be diffolved in
alcohol, but it does not retain the odour. Mufk is
foluble in fulphuric and nitric acid j but in thefe io-
lutions the odour is diffipated. The imeil of ammonia
is given out by the a£tion of the fixed alkalies on
mufk. When it is laid on red hot iron, it takes fire,
and is almofl entirely confumed, leaving only a fmall
portion of gray allies. During its combuflion it gives
out the fetid odour of urine. Mufk feems to poffefs
many of the properties of the volatile oils, but its
component parts have not been determined.
6. Civet.—This fubftance is extracted from a fmall
bag near the anus of the viverra civeta, or civet cat.
It is of a yellow colour, and of the confiftence of but¬
ter. When firft extrafted it is faid to be white. It
has a very ftrong fmell, and {lightly acrid tafte j it
combines readily with oils, and is much employed as
a perfume.
7. Cajlor.—This fubftance is extrafted from two
bags fituated near the anus of the beaver. The beft
caftor is obtained from the large bag; that which is
fecreted in the fmall bag is faid to be of an inferior
quality. When caftor is firft taken from the animal,
it is nearly fluid, and of a yellow colour. After it is
expofed for fome time to the atmofphere, it becomes
hard, and of a darker colour, affuming a refinous ap¬
pearance. It has an acrid, bitter, and naufeous tafte,
and a ftrong aromatic fmell, which it lofes by drying.
It becomes foft in water, and communicates to it a pale
yellow colour. This infufion converts vegetable blues
to a green colour. When it has been long macerated
in water, the infufion becomes of a deeper colour, and
yields by evaporation extrattive matter, which is fo¬
luble in alcohol and in ether. A refinous matter is
precipitated from the folution in alcohol, by means of
water, which has fimilar properties with the refin of
bile. According to the analyfis of Lagrange, the
component parts of caftor are the following
Carbonate of potafh,
 lime,
  ammonia,
Iron,
Refin,
Mucilaginous extractive matter,
Volatile oil.
767
Component
Parts of
Animal
Subftances.
rfss
Civet.
2856
Caftor.
2852
Hart thorn.
2853
Wool.
2854
MiUk.
100.0
3. Hartfhorn.—The conftituent parts of haftfhorn,
from the analyfis which has been made, are exactly the
fame as thofe of bone, but they contain a greater pro¬
portion of gelatinous matter.
4 Wool is a kind of long hair, very fine and foft,
which is a covering to different animals, efpecially the
flieep. It has been confidered as nearly analogous in
its nature and properties to hair. It is entirely folu¬
ble in the cauftic alkalies, and forms with them a
foapy matter, which has been employed, it is faid, with
advantage, as a fubftitute for foap, in different manu-
fadures.
5. Mufk is a fubftance which is fecreted in a bag
fituated near the umbilical region of the mufk deer
(mofehus mofehifer). It has an unCIuous feel, is of a
dark-reddifti brown colour, has a very bitter tafte, and
8. Ambergris.—This is a fubftance which is fup-
pofed to be formed in the inteftines of the fpermaceti
whale. It is frequently found floating in the fea. For
its natural hiftory, fee Ambergris, and Cetology
Index.
It is a foft light fubftance, of an afli-gray colour,
with brownifli-yellow and white ftreaks. It has an
infipid tafte, but an agreeable odour. The fpecific
gravity is from 0.844 to 0.849. It melts at the tem¬
perature of 1220, and with the heat of boiling water
is completely diflipated in white fmoke, leaving a final!
trace of charcoal. By diftillation an acid fluid is firft
obtained, and a light volatile oil 5 and there remains
behind a voluminous mafs of charcoal. By fublima-
tion benzoic acid is feparated.
Ambergris is infoluble in water. Concentrated
fulphuric acid feparates a fmall portion of charcoal.
It
2857 .
Ambergris*
Component
Parts of
Animal
Subitances.
1858
Compofi-
tion.
CHEMISTRY.
It is diffblved in nitric acid. During the folution, ni¬
trous gas, azotic gas, and carbonic acid gas are evol¬
ved. A refinous matter is obtained by evaporating
the folution. Ambergris is foluble in the alkalies,
with the afliftance of heat. It is alfo foluble in the
oils, in alcohol and ether. By the analyfis of Bou¬
illon la Grange the conlfituent parts of ambergris are
the following :
II. Of Subftances peculiar to the Oafs of Birds. Component
Parts of
The fubftances which are peculiar to this clafs of Animal
animals are the following. Subftances^
I. Eggs.
i. Feathers.
3. Excrement.
4. Membrane of the flomach.
Adipocire
Refin
Benzoic acid
•Charcoal
* Ann. de
Chim.
xlvii. 84.
100.0 *.
2859
Spermaceti
2860
Properties.
2861
Adtion of
acids, See.
2862
Bezoards.
The fubftance called adipocire poflefies the mixed or
intermediate properties of fat and wax. This name was
firfl: given by Fourcroy to the matter into which the
dead bodies found in the Innocents burying-ground
were converted. In appearance and fome of its pro¬
perties it alfo refembles fpermaceti.
9. Spermaceti.—This is a production of the fame
whale which yields the preceding fubftance. It is an
oily matter which furrounds the brain. It is fepara-
ted from a fluid oil, with w^hich it is mixed, by ex-
preflion. Spermaceti is alfo found in other cetace¬
ous fifties, and in other parts of the body, mixed with
the oil.
It is a fine white fubftance of a cryftallized texture,
very brittle, and has little tafte or fmell. It cryftal-
lizes in the form of fhining filvery plates. It melts
at the temperature of 1120. With a greater heat it
may be diftilled without change ; but, by repeated
diftillation, it is decompofed, and partly converted into
a brown acid liquid. It is foluble in boiling alcohol*
but it feparates when the folution cools. It is alfo fo¬
luble in ether both cold and hot. In the hot folution
it concretes on cooling into a folid mafs.
Spermaceti is fcarcely at all foluble in the acids.
It combines readily with the pure alkalies, with ful-
phur, and with the fixed oils. By expofure to the
air it becomes rancid. The ufes of fpermaceti are
well known, and particularly in the manufa&ure of
candles.
.10. Be%oards.—Thefe are calculous concretions
which are found in the inteftines of different animals
belonging to this clafs, particularly the horfe. Some
of very large fize have been found in the elephant and
:0e rninoceios. T. hefe fubftances w7ere once celebrated
on account of their medical virtues, and they were
formerly diftinguiftied into oriental and occidental.
The firft were moft highly valued, and frequently bore
a high price, efpecially the bezoards obtained from a
fpecies of goat which inhabits the Afiatic mountains.
Some that have been examined were compofed entire¬
ly of vegetable matter. _ In general the nucleus is of
vegetable matter, on which phofphate of ammonia and
magnefia or phofphate of lime have been depofited.
I hefe fubftawces are diftinguifhed by a ftrong aroma¬
tic odour when they are rubbed or reduced to powder.
'I he brown or golden-coloured matter which has been
obferved on the grinding teeth of ruminating animals
rs found to be of the fame nature with the bezoards
which are formed in the inteftines.
r. Eggs.—In a chemical view, three parts of an egg Eggs. 3
merit attention. Thefe are the ihell or external co¬
vering, the white, and the yolk. The white of egg,
which confifts of albumen, has been already deferibed,
fo that it now only remains to give fome account of
the (hell and the yolk.
The (hells of the eggs of birds which have been Sheftsf4
analyzed are compofed of fimilar conftituents with bone,
but in very different proportions. The following is
the refult of the analyfis of Vauquelin.
Carbonate of lime
Phofphate of lime
Animal matter
The yolk of egg is of a foft confidence, a yellow yoi^5
colour, and of a mild oily tafte. It becomes folid by
boiling, and crumbles eafily into fmall particles. By
heating gently after it has been boiled, and by expref-
fion, an oily liquid of a yellow colour and infipid
tafte is obtained. It is diftinguiftied by the properties
of fixed oil. What remains after feparating the oil is
albumen, ftill coloured with a fmall portion of oil.
By boiling this refiduum in water, a portion of gela- 2S66
tine is obtained, fo that the yolk of egg is compofed c.oniPofl“
of oil, albumen, gelatine, and water. tl0n'
2. Feathers—are confidered as poflefling fimilar pro-Feathers,
perties with hair. According to fome, the folid part,
or quill, may be reduced to the gelatinous ftate by
boiling; but according to others, no gelatine whatever
can be detefted. The quill part is therefore fuppofed
to confift chiefly of coagulated albumen. It be¬
comes fblt by the aftion of acids and alkalies. 286S
’ 3. Excrement.— Phis matter in birds is very different Excrement
from that of the animals included in the clafs mammalia.
It is generally of a white colour, lefs liquid, and lefs
fetid. It is commonly accompanied wflth a glary mat¬
ter of different degrees of tranfparency, analogous to
the white of egg. 'Phis feems to be owing to a quan¬
tity of albumen w hich is fecreted in the ovidudl. The
white part of this matter is compofed of carbonate and
phofphate of lime and albumen. The colouring mat¬
ter feems to be part of the food.
4. Membrane of the Jiumach.—The internal furface Membrane
of the gizzard, or mufcular part of the ftomach of birds, of the fto-
is covered with a wrinkled membrane, which is fuf-mach-
ceptible of confiderable extenfion, and through the pores
of which gaftric juice is copioufty fecreted. This mem¬
brane is eafily leparated from the mufcular part. When
it is boiled in water, it is converted into jelly, and com¬
municates to the water the property of reddening ve- : c
getable blues, and coagulating milk. When it is
dried and reduced to powder, it produces the fame
effed.
89.6
5-7
4-7
100.0 *
* Ann. de
Chim. XXlX.
6.
III. Of
2863
Poifon of
the viper.
C H E M
Component
Par s of III. Of Matters peculiar to Animals in the Amnhibi-
0 ^,mal ous Oafs.
Subltances.
I. 'Poifon of the Viper.—Some of the animals be¬
longing to the fnake tribe, fecrete a peculiar fluid in
the mouth, which is of a poifonous quality. The poi¬
fon of the viper is a yellow, vifcid liquid, fomewhat
refemblmg oil. It is fecreted in two fmall bags, and
from them conveyed to the fangs of the animal, which
are hollow and perforated, and when it bites, the li¬
quid is Squeezed out of the bag, and flows through
the teetn into the wound. It has no fmell. It be¬
comes thick by expofure to the air, and is converted
into a tranfparent jelly j but it retains its poifonous
property long after it is feparated from the animal.
It is foluble m water by agitation, but if thrown into
the water when extrafted from the veficle, it falls in-
ftantly to the bottom like a heavy oil. It is foluble
in warm water after it is dried, but not foluble in al¬
cohol, or coagulated by boiling water. Acids and
alkalies produce no perceptible change upon this mat¬
ter. It is precipitated from its folution in water by
alcohol. It refembles gum in fo many of its proper¬
ties, that it has been called an animal gum.
2. Liquid fecreted from the tubercles on the head of
the Toad.—It has been long fuppofed that the liquid
ecreted on the head of the toad is of a poifonous qua-
ity J but although it is faid by fome naturalifls, that
this fluid, brought in contaft with the fkin, produces
inflammation, yet there feems to be no pofitive proof
of this effeft. F
3* Tortoife-fhell.—This fubftance, which forms a
ftrong covering and defence to the body of the turtle
ponefles many of the properties of horn $ for it may be
foftened with heat, or in boiling water, and fhaped in¬
to any form which may be wanted. It is compofed
of a number of hard plates or membranes, of different
degrees of thicknefs, clofely applied to each other. It
becomes. foft by maceration in nitric acid, and by
burning it yields a very fmall proportion of phofphate
or lime and foda, with fome flight traces of iron.
Toad.
2870
Tortoife
iliell.
1 S T R Y. 769
fifhes, pofTefTes different properties, which are afcribed Component
to the difference in the function of refpiration of ceta- Patts ot
ceous and other fifhes; but how far this difference real-* ^imaI
y. exi^s> does not feem to have been accurately afcer-, u ances‘
tamed. fifh oil is diftinguifhed by a difagreeable
imell, and it has long been an object to deprive it of
this odour,^ as it is much employed in domeflic econo¬
my and in many arts. By agitating the oil with a
.all portion of fulphuric acid, and adding water, the
oil when left at reft, rifes to the furface confiderably
purified. A portion of coagulated matter has feparat¬
ed, and the water is milky.
V. Of Subftances peculiar to Infers.
1. -The nature and properties of this fub¬
ftance have already been defcribed as a vegetable pro-
duftion.
2. Propolis This is a fubftance colleaed by bees, 2S73
and with which they cover the bottom of the hive, or Propolis,
any foreign matters which happen to be introduced in-
to it, which they cannot remove. It is the fubftance
which they colled on their legs and thighs. It is per¬
haps more properly to be confidered as a vegetable
produdion. It poffeffes more tenacity than wax
but has much of its dudility. It is infipid to the tafte,’
but is diftinguifhed by an aromatic odour. It is par¬
tially foluble in alcohol, to which it communicates a
red colour. Another portion is diffolved in boiling
alcohol, and part precipitates as the folution cools,
which has the properties of wax. A refinous mafs is
obtained by concentrating the folution in alcohol and
boiling m water. B is femitranfparent and brittle. An
acid was deteded in the_ water in which it w^as boiled.
The refinous lubftance is foluble in fixed and volatile
oils. The following are the conftituent parts of pro¬
polis.
^871
Scales.
IV. Of Subftances peculiar to Fifhes.
57
*4
*4
*5
100 ;
I. Scales generally poffefs a filvery whitenefs, and
are compofed of different laminae. In many of their
properties they referable horn. By long boiling in
water they become foft, and when they are kept for
ome hours in nitric acid, they are converted into a
tranfparent membranous fubftance. By faturating the
acid with ammonia, a precipitate is formed, which is
phofphate of lime. The conftituent parts of fcales,
2872 therefore, are membrane and phofphate of lime.
Senes, 2. Bones of fifhes.—Thefe are compofed of the
fame conftituents as thofe of other animals, but have a
greater proportion of animal matter. In fome they are
loft, flexible, and femitranfparent, and hence they are
called cartilaginous. In others they are hard and folid
having the ufual appearance of bone.
3. Fifh oil.—A great quantity of oil is extraded
from the foft parts of different kinds of filh, and efpe-
cially from the blubber of the whale. It is ufually
denominated train oil. It is obtained, either bv ex-
preflion, or by boiling. It is fuppofed that the oil ob¬
tained from the blubber of the whale, and from other
Vox. V. Part II.
Pure refin
Pure wax
Extraneous matter
Lofs and acid
* Nichol.
your. v.
p. 49.
3. Honey. This has alfo been confidered as a ve-Honey4
getable produdion, as it is colleded from plants by
bees. It is of a white or yellowifti colour, of a gra¬
nular foft confiftence, and has an aromatic fmell;
but thefe properties vary according to the plants from
which it is colleded, or the climate in which they
grow. By diftillation honey yields nearly the fame
produds as fugar. It is converted into oxalic acid by
means of nitric acid. It is very foluble in water, and
is even fomewhat deliquefeent. It readily paffes to
the vinous fermentation, and affords a fermented li-
quor which has been called hydromel. It is partially
oluble m alcohol, and by this means fugar may be
extraded from it. The component parts of honey are
iugar, mucilage, and an acid. If pure honey be melt¬
ed, and carbonate of lime be added till the effervef-
cence ceafes, the fygar is feparated, and is depofited
m cryftals. r
4. Camharides are a fpecies of fly, (the mehe
catorius, Lm.) which are much employed, from a pe-des.
cuhar property they poffefs, to raife blifters on the
ikm. lor this purpofe the whole of the infed is re-
5 E duced
77°
Coinponent
Farts of
Animal
Sub fiances.
2876
Millepedes,
2877
Ants.
287S
Lac.
2879
Silk.
C H E M I
duced to powder. Cantliarides have been fubjected
to aoaVyfis •, and by fucceflTive treatment with water,
alcohol, and ether, four different fubftances have been
extraded. 1. Three eighths of their weight confift
of extradive matter, of a reddifh-yellow ‘ colour, very
bitter, and which yields by diifillation an acid liquor.
2. A little more than one-tenth of the weight coniilts
of a concrete oil, fomething of the nature of wax,
which is of a green colour and very acrid talfe. I o
this is owing the peculiar odour of cantharides. This
fubftance yields by diftillation, a very pungent acid
fubftance and a thick oil. 3* About one-fiftieth of a
yellow concrete oil, which leems to communicate the
colour to the infed, is alfo obtained. 4* About one-half
the weight of a folid matter remains, the nature of
which has not been afcertained. The bliftering effed
of cantharides feems to depend on the green w'axy
matter, part of which is extraded by means of warm
water, and it is entirely foluble in ether.
Millepedes.—Thefe infeds, which are differentfpecies
of onifcus, wTere formerly employed in medicine.. By
diftillation with the heat of a water bath, they yield a
watery liquid, which converts the fyrup of violets to a
green colour, and by this procefs they are deprived of
five-eighths of their weight. By treating them after¬
wards with w'ater and alcohol they furnifh one-fourth
of their weight of an extradive and w^axy matter j
the latter is foluble in ether. The muriates of potafh
and lime have been deteded in the expreffed juice of
thefe infeds.
j4nts.—Thefe infeds contain an acid liquid which
they emit from the mouth when they are irritated, or
when they are bruifed on paper. This liquid converts
vegetable blues to red ; and it has been obferved that
llreaks of the fame colour are communicated to blue
flowers, over which the infeds creep. The acid obtained
from ants, and particularly from the formica rufa, or
red ant, was formerly confidered as poffefling peculiar
properties, and thence denominated formic acid; but
it has been lately afcertained to confift of a mixture of
acetic and malic acids.
Lac.—This is a fubftance which is formed on the
branches of feveral plants, as the feus indica, the feus
religiofa, and efpecially the croton lacciferum. It is
produced by the pundure of an inled, but is confider¬
ed as belonging to vegetable fubftances, among which
the general properties have been already delcribed, as
well as the properties of an acid obtained from it,
among the acids.
Bilk.—This is the produdion of feveral infeds, ei¬
ther for the purpofe of covering up their eggs, or
forming a net to catch their prey, as is the cafe with
many of the fpider tribe, or to cover up the infed du¬
ring one of the ftages of its metamorphofis. The filk
of commerce is ufually obtained from thephalcena.bom-
byx, or filk-wTorm. This fubftance is prepared in the
body of the larva of the infed, from which it is pro¬
truded through feveral fmall orifices in very fine threads ;
and with this it forms a covering for itfelf while it re¬
mains in the ftate of chryfalis or pupa.
Silk is a very elaftic fubftance, and is of a white or
reddilh yellow colour, when it is produced by the in-
fed. The elafticity of filk has been aferibed to a var-
nilh with which it is covered, of a gummy or gelati¬
nous nature, which is precipitated by tan and muriate
S T R Y.
of tin. The yellow colour of filk is aferibed to a re- Component
finous matter which is foluble in alcohol. By diftilla-
tion filk yields a large proportion of ammonia. It is Subftance9.
loluble in fulphuric, nitric, and .muriatic acids. By' <
nitric acid it is partly converted into oxalic acid, and
a fatty matter which fwims on the furface. ‘ 2Sgo
Cochineal.—This is an inled which breeds on the CQciuneal,
leaves of the cadlus coccinclliferus Lin. fometimes
called opuntia or nopal. The plant is cultivated in
Mexico, for the purpofe of rearing the infeds, which
are colleded, dried, and employed as a beautiful dye
fluff. By burning, the fame refults are obtained as
from other animal matters •, but with, boiling water it
gives a enmfon violet colour, which becomes red
and yellow by the adion of acids, while a precipitate
is formed of the fame colour. The metallic folutions
added to this decoddion, alfo produce a coloured pre¬
cipitate. The muriate of tin throws down a beautiful
red precipitate. The evaporated refiduum of the de-
codion of cochineal, treated with alcohol, gives a fine
red colour, and this, by evaporating the alcohol, af-
fumes. the form of a refin. Oxymuriatic acid converts
the folution of this fubftance into a yellow colour,
from which the proportion of colouring matter may be
in fpme meafure eftimated, by the quantity or acid re-
quifite to deftroy its colour. Cochineal is well known
by its producing a beautiful fcarlet colour. It may
be kept for any length of time, at leaft in a dry place,
without being deprived of its colouring matter. It has
retained this property for 130 years. Cochineal is em¬
ployed in the preparation of the beautiful laice called
carmine. ' 2881
Kermes This alfo is an infed which is employed Keimes.
in dyeing, from whence it has been called coccus in-
fefforius. It is the coccus ilicis Lin. and is produ¬
ced on a fmall kind of oak, the quercus coccifera.
The infed attaches itfelf to the bark of the tree by a
foft fubftance, which poffeffes many of the properties
of caoutchouc.
When the living infed is bruifed, it gives out a red
colour. It has a ftightly bitter, rough, pungent tafte,
but its fmell is not unpleafant. The dried infed, or
the kermes, imparts this odour and tafte to water and
to alcohol, and communicates alfo to thefe liquids a
de'ep red colour. By evaporation, an extrad of the
fame colour is obtained. It is employed in dyeing,
and has been alfo ufed in medicine. __ _ 2S82
Crabs eyes.—The fubftance which has received this Crabs eyes,
name, merely from its form, is a concrete body, con¬
vex on one fide, and concave on the other. Two of
thefe bodies are ufually found in the ftomach of the
crab, about the time that it changes its ftiell. After
the fhell is fully formed, they are no longer found, fo
that they are fuppofed to furnifh the materials of the
new fhell. They are entirely compofed of carbonate
of lime, a fmall proportion of phofphate of lime, and
gelatine.
The cruftaceous coverings of the crab, lobfter, and
fimilar animals, are compofed of carbonate of lime,
phofphate of lime, and animal matter, or cartilage.
VI. of Subftances peculiar to Teftaceous Ani¬
mals.
The only fubftances to be mentioned peculiar to
' this
C H E M
Component this clafa of animals are, fliells, mother of pearl, and
Parts of pearl.
Animal Shells.—Such as have been particularly examined
Subft.nxes. ^ fjatchett, are divided into two clafles. In the
4883 one he includes thofe which have the appearance of
Shells. porcelain, and have an enamelled furface, which he
calls porcellaneous [hells. Such are the various fpecies
of valuta and cypreea. Thefe fliells were found by
analyfis to be compofed of carbonate of lime, with a
2884 fmall portion of animal gluten.
Mother of 2. Mother of pearl.—The fecond clafs comprehends
pearl. thofe which are generally covered with a ftrong epider¬
mis, under which is the fliell, compofed chiefly of the
fubftance called nacre^ or mother of pearl. Such are
the oyjler, the river muffel, the hchotis iris, and the
turbo olearius. In thefe the proportion of carbonate of
lime is fmaller, and that of the animal matter, greater.
1? id*8** 3- Pearl.—This is a concretion formed in feveral fpe¬
cies of (hells, as in fame fpecies of the oyfter andthe muflel.
It is confidered by fome as a morbid concretion, owing
to an excefs of the flielly matter, or to a wound of the
fhell containing the animal. Pearls are of a fllvery or
bluifli-white colour, iridefcent and brilliant. The
refraction of the light is afcribed to the lamellated
ftruCture, for they conflft of concentric layers of car¬
bonate of lime and membrane alternately arranged.
The conftituent parts of pearl are the fame as mother
of pearl.
VII. Sabftances peculiar to Zoophytes.
Zoophytes. The zoophytes, many of which have been examined
by Mr Hatchett, are compofed of carbonate of lime,
phofphate of lime, and animal matter of different de-
I S T R Y. 771
grees of confiftency. In fome the eonftituents are on-Component
ly carbonate of lime and a celatinous matter. Such Parts
J r r . r . ,0 , , Animal
are lome ipecies or the madrepore, as the maarepora Subftances.
muricata, virginea, and labyrinthica ; iome fpecies of ——y—J
millepore, as the millepora cerulea and alcicornis, and
the tubipora muftca. Others again are compofed of
carbonate of lime and a membranaceous fubftance.
Such are the madrepore fafacularis, the ttiillepora cel-
lulofa and fafcialis, and the iris hippuris. White co¬
ral and articulated coralline are compofed of fimilar
fubftances. Another divifion of zoophytes are com¬
pofed of carbonate of lime, a fmall portion of phofphate
of lime, and membrane. Such are the madrepora poly*
morpha, the gorgonia nobilis or red coral, and the gor*
gonia fetofa; but fome of the zoophytes are alfo
found to conftft chiefly of animal matter, with fcarcely
any portion of earthy fubftance. To this divifion be¬
long fome fpecies of gorgonia, and many fpecies of
fponge.
Chap. XX. Of Arts and ManufaElures.
In this chapter it was intended to give a general
view of the application of the principles of chemiftry
to different arts and manufaftures, fuch as the manu-
fatture of foap, of glafs and porcelain •, the arts of dye¬
ing, bleaching and tanning. In this view it was pro-
pofed to explain the principles of th: fe arts and manu-
fa&ures, fo far as they depend on chemiftry, leaving
the detail to the different treatifes on thofe fubje&s in
the courfe of the work. But the unavoidable length
to which this article has extended, obliges us to refer
our readers for the whole to the different treatifes.
APPENDIX.
After the chapter on earths was printed off, we re-
Tceived the account of a new earth difeovered by Kla¬
proth.
Of Ochroit. This earth was difeovered in a mine¬
ral to which Klaproth has given the name of ochroites,
of which the external charafters are the following:
I. The colour of this mineral is between carmoifin
red, clove-brown, and reddifh-brown. It is compaft,
breaks fplintering in irregular but not very (harp or
angular pieces. It is perfectly opaque, the powder is
reddifh-gray *, it is not very hard, but brittle. The
fpecific gravity is 4.60. This mineral is found in the
mine of Bafnaetes, near Riddarhytta in Weftmann-
2887 land.
Analyfis of A. “ a. A piece of the mineral, after having been ig-
the och- nited to rednefs, loft two per cent. Its reddifh colour
roites. been changed to brown. Its figure had fuffered
no alteration.
“ b. One hundred grains of the finely levigated mi¬
neral ignited for half an hour, loft five grains. Its co¬
lour was changed to a dark brown.
B. a. One hundred grains of ochroit, after being
mixt with 200 grains of carbonate of potafh,were flrong-
ly ignited, the mafs which could not be rendered fluid,
was reddifh gray, and brittle. On being diffufed
through water, as ufual, the obtained folution was co-
lourlefs. It remained perfe&ly tranfparent ; a proof
that it did not contain tungften oxide ; nitrate of filver,
mercury, lead, barytes, &c. proved the abfence of
acids.
b. The infoluble refidue of the laft procefs was boil¬
ed in nitro-muriatic acid, the filiceous earth being fe-
parated, the folution was decompofed by potafh, and the
whole boiled for fome time. The alkaline fluid after
being neutralized with muriatic acid, and then mingled
with carbonate of potafh, fuffered no change.
C. a. Two hundred grains of the finely pulverized
mineral, wrere firit boiled in two ounces of muriatic
acid, to which half an ounce of nitric acid was gra¬
dually added, and the digeftion continued for fome time.
The whole became thus diffolved except the filex con¬
tained in the mineral. Its quantity amounted to 68
grains.
b. To the folution obtained in the laft procefs, car¬
bonate of ammonia was added fo long, till no perma¬
nent precipitate was produced. On letting fall into it
fuccinate of ammonia, a curdly precipitate fell, which
vanifhed again on agitation, leaving merely a pale red
5 E 2 precipitate
772
Ochroit
Earth.
a888
Peculiar
earth.
C H E M
precipitate of fuccinate of iron. This being collected,
wathed, dried, and ftrongly ignited, yielded nine grains
of oxide of iron.
c. The fluid thus freed from iron, and now colourlefs,
was decompofed by carbonate of ammonia. The pre¬
cipitate obtained was white, and weighed 168 grains;
on being deprived of water and carbonic acid by heat,
its white colour changed to cinnamon-brown. It
weighed 109 grains.
d. All the water employed for wafliing the different
precipitates were mingled,evaporated todrynefs, and the
ammoniacal fait volatilized ; a minute quantity of a
muriate was obtained, the balls of which could not be
determined.
From what follows it will become evident, that the
cinnamon-brown precipitate (c.) which forms the princi¬
pal part of the foflil, is a peculiar earth, diftinct from
all the others hitherto known. The charadteriftic pro¬
perty which it poflefles of acquiring a light-brown co¬
lour after being heated, has induced me to call it
ochroit earth (a), which may alfo ferve for the mineral
itfelf.
According to this analyfis, 100 parts of the ochroit
of Riddarhytta contain,
Ochroit earth,
Silex,
Oxide of iron,
Water, &c. (A. £.)
Lofs,
54.5°
34
4
5
2
100
CharaBcriJlic Properties of Ochroit Earth.
2! 89
Ochroit I. Ochroit earth is capable of combining with car¬
bines wTh b°nic acid du.rinS itS Prec'P'tati°n from acids by car-
carbonic honated alkalies, and ftrongly confolidating a portion
acid, of water.
One hundred grains of the earth precipitated by
carbonate of ammonia, and ftrongly dried, loft on be¬
ing neutralized by nitric acid, 23 grains r 100 grains
of the fame earth loft, after being ftrongly ignited,
35 grains : 100 parts of carbonate ochroit, therefore!
confifts of ’
Ochroit earth
Carbonic acid
Water
65
23
12
100
2. Ochroit earth, after being freed from carbonic
acid and water, by heat, always appears in the form of
a cinnamon-brown powder. The intenfity of the co¬
lour is in proportion to the heat applied. This colour
is not owing to the prefence of iron, or manganefe &c.
but it is a chara&eriftic property of the earth. *
3. Ochroit earth included in a charcoal crucible, and
expofed to the heat of the porcelain furnace, fuffered
no change whatever.
4. Urged by the blow-pipe, it becomes phofphoref-
I S T R Y.
cent; fufed with phofphate of foda and ammonia
it becomes tinged by it, without effe&ing a folution of
the earth. The fait acquires merely a marbled lemon-
yellow colour. Borax has likewife no chemical effeft
upon it. This fait only effe&s a mechanical divifion.
The earth always appears diffufed through the borax in
minute flocculi.
5. Ochroit earth mixed in different’proportions with
proper fluxes, and applied for painting of porcelain,
proved unfuccefsful. The painted articles were light-
brown, but the colour was not uniform ; a proof that
no combination had been effefted.
6. Ochroit earth combined with carbonic acid is
eafily foluble with effervefcence in acids. The tafte
of the folution is very rough and aftringent. The
concentrated folution is of an amethyft-red colour;
diluted with water, it becomes colourlefs. Ignited
ochroit earth, on the contrary, is difficultly foluble in
acids in the cold ; if nitric acid be employed, the folu¬
tion is yellowiffi red.
7. The combination of ochroit earth with fulphuric
acid, is cryftallizable. The figure of the cryftals form¬
ed in the mafs of the fluid is the o&ahedron. They
are heavy, of a pale-amethyft colour, and difficultly
foluble in water ; but the fulphate of ochroit, with
excefs of acid, is more foluble ; the figure of the cry¬
ftals formed on the fides of the veffel, is needle-fliaped,
radiating from a centre. They are more foluble than
the former.
8. If a folution of fulphate of foda be mingled with
a folution of muriate or nitrate of ochroit, a mutual de-
compofition takes place. A white infoluble precipi¬
tate is formed, confifting of fulphuric acid united to the
ochroit earth. This combination may be decompofed
by boiling it with double its weight of carbonate of
foda. By this means ochroit earth may be obtained
very pure.
9. Ochroit earth is likewife foluble in fulphurous
acid, the folution cryftallizes in needles of a pale ame-
thyft colour.
10. Muriatic acid diffolves ochroit earth, and yields
cryftals, the figure of which is the prifm. It is folu¬
ble in alcohol without imparting to its flame any par¬
ticular colour.
12. Acetite of ochroit could not be cryftallized, but
yielded an adhefive mafs.
13. Nitrate and muriate of ochroit are decompofa-
ble by carbonated earths and alkalies, the precipitate
is milk-white. Alkalies and earths freed from carbonic
acid, occafion a yellowilh-gray precipitate.
14. Pruffiate of potaffi precipitates ochroit from all
its neutral folutions, milk-white. The precipitate is
foluble in muriatic and nitric acid (b).
15. Finfture of galls occafions no change in the fo¬
lutions of this earth.
16. Hydroguretted hydrofulphuret of ammonia preci¬
pitates the folution of ochroit earth, yellowiffi white.
17. Water impregnated with fulphurated hydrogen
occafions no change in the folutions of ochroit earth.
18. Succinates precipitate ochroit earth white.
19. Phofphate
Ochroit
Earth.
(b) If the earth contatnpJoT1 ^ 5^ree^ j7°rd "W0** {flwefcens), browniffi-yellow.
t e muriates and quality of iron, it becomes by this means manifefted.
\
C H E M
Qchroit 19. Phofphate of focla occafions in the folutions of
Earth, earth a white precipitate, which again vanifhes by
v the addition of nitric or muriatic acid.
20. Tartrites of potaih alfo precipitate this earth
■white.
21. Oxalates effeft a like decompofition, the oxa¬
late of ochroit, however, is not foluble in nitric or
muriatic acids.
22. Alkalies and alkaline carbonates do not aft on
ochroit earth.
23. Ammonia feebly a&s on it, under certain cir-
cumflances, as may be evinced from the following ex¬
periment :
A folution of nitrate of ochroit, prepared by dif-
folving 100 grains of carbonate of ochroit (not abfo-
lutely free from iron,) in nitric acid, was decompofed
by carbonate of ammonia, and digefled in the fluid,
containing a confiderable quantity of carbonate of am¬
monia in excefs, for fome days. The fluid which had
acquired a yellow colour, was feparated and neu¬
tralized by fulphuric acid, and then fet in a warm
place. A gray precipitate was thus obtained, which,
I S T R Y.
on being dried, weighed 1-3- grains. This precipitate,
after being diflblved in nitric acid, yielded a blue pre¬
cipitate by prufliate of potaflr ; this being feparated, a
white flocculent precipitate fell down by dropping into
the remaining fluid carbonate of potafh. This method
is, therefore, applicable for feparating a minute quantity
of iron, that may be contained in the fluid.
“ From what has been ftated, it becomes obvipus, that General re.
marks and
773
Ochroit
Earth.
2S90
the ochroit earth bears the neareft relation to yttriaj
for, like this, it forms a connefting link between the ^^ch
earths and the metallic oxides. Like yttria, it hasroit
the property of forming a reddilh coloured fait with
fulphuric acid, and is precipitable by prufliate of pot-
aflr j but differs from yttria, that it does not form
fweet falts, that it is not (at leaft very fparingly)
foluble in carbonate of ammonia j and that, when
ignited, it acquired a cinnamon-brown colour. It
farther differs from yttria by not being foluble in
borax or phofphate of foda when urged upon char¬
coal before the blow-pipe, which falts eafily effeft a
folution of yttria, and melt with it alfo into a pellucid
pearl” *„ * Nidol.
Jour, viii-.
p. 31*.
ERRATA 1
P.483.1. 2 2. col. iff. EavBerthollet read Bartholdi.
P.508.1. xo. col. 2d. It is faid that Mr Keir found that
fulphuric acid froze at 450 Fahrenheit. This
is only inferred from the thermometer being
EXPLANATION
Plate CXLII.
Fig. I. Reprefents Harrifon’s pendulum conftrufted
on the principle of the unequal expanflon of metals.
Fig. 2. The calorimeter of Lavoifier and Laplace,
fee page 476.
Fig. 3. Iron bottle and bent gun-barrel for procu¬
ring oxygen gas from manganefe. The black oxide is
reduced to powder, and introduced into the bottle A.
The bent tube is put on the mouth of the bottle at C,
and luted with the materials defcribed at the foot of
page 490. The bottle is then expofed to a red heat,
and the gas which comes over is received in jars on
the pneumatic apparatus.
Fig. III. and 4. reprefent the apparatus for the de¬
compofition of water. See page 496.
Fig. 5. Pneumatic trough for colledfing gafeous
bodies. Suppofe a quantity of fulphurated hydrogen
gas is to be colledled, which is defcribed in page 505.
The iron filings and fulphur which were melted toge¬
ther in a crucible, and which then form a black brittle
mafs, are to be introduced into the glafs veffels. Fig.
6. B is a bent tube ground to fit the mouth D, and is
air-tight. To the other mouth C is fitted the ground
Hopper A. One end of the bent tube is fitted into
the mouth D, and the other placed under the glafs jar
F on the (helf of the pneumatic trough E, which is
filled with water about an inch above the furface of
the flielf. The jar is alfo previoufly filled with water,
cautioufly inverted, and fet on the Ihelf. The apparatus
'n CHEMISTRY.
ftationary at 45® during the melting of the
frozen acid. A greater degree of cold
was always found neceffary for its congela-'
tion. Phi/. Tranf. 1787. p. 279.
of the PLATES.
being thus adjufted, muriatic acid is poured into the open¬
ing C, and the ground ftopper is immediately replaced.
A violent effervefcence takes place, a great quantity of
gas is difengaged, and as there is no other way for
it to efcape it pafles into the glafs jar. When this
is filled, it is removed to another part of the flielf •, ano¬
ther jar which was previoufly filled with water is
put into its place, and fo on till the whole gas is col-
le&ed.
Fig. 7. Papin’s digefter. A is the body of the vef-
fel, which has been generally made of copper or iron,
very thick and ftrong. BB are two ftrong bars fixed
to the fides of the veffel. To the upper end of thefe
bars is fixed the crofs bar C, through which paffes
a ftrong fcrew D, which preffes on the lid of the
veffel at E, fo that it is enabled to refill the elaftie
force of the vapour; and the water can thus be
railed to a higher temperature than the ordinary boil¬
ing point.
Fig. 8. This reprefents an apparatus for diftilla-
tion. A is the furnace, B is the body of the Hill,
which is generally made of copper •, C is the top or
head, made of the fame metal. The vapour as it rifes
from the liquid by the application of heat, paffes along
the tube D, which communicates with a fpiral tube
in the refrigeratory E, which being filled with cold
water, the vapour is condenfed, and paffes out at the
other extremity of the tube F, and is received in the
veffel G.
Plate
774
Explanation
of Plates.
C H
Plate CXL1II.
9. Glafs Retort.
E M I S T R Y,
Fig. .
F/g. 10. Tubulated retort.
Fig. 11. Glafs Alembic.
Fig. 1 2. Solution glafs.
Fig. 13. Crucible.
Fig. 14. Apparatus for obtaining muriatic acid from
muriate of foda by fulphuric acid. The muriate of
foda is introduced into the retort A, and by means of
the bent tube B the fulphuric acid is added. The ma^
trafs C is adapted to the retort, to receive the portion
of impure fulphuric acid and muriatic acid which paffes
over towards the end of the operation. D, E, and F,
are bottles containing water j the quantity of which
fhould be equal in weight to that of the fait employ¬
ed. Thefe bottles are furnifhed with tubes of fafety
G G ; or the tube of fafety may be applied as H in the
bottle E.
Fig. 15. Apparatus for impregnating fluids with
gafes. A is a tubulated retort which is joined to B,
a tubulated receiver, from which a bent tube C palfes
to the fecond receiver D. This laft communicates with
the bottle F by means of the bent tube E. The end of the
tube C which enters the teceiver D, is furniflied with a
valve which prevents the return of any gas from the Explanation
receiver D to the receiver B, in cafe a vacuum fiiould 01 ^ates.^
take place in the courfe of the operation in the receiver v " "i
B, or in the retort A. The gas which is not abforbed
by the water in the receiver D, paffes through the tube
E to the bottle F.
lig. 16. A gazometer, which is a convenient ap¬
paratus for holding gafes. It is ufually made of tin
plate. A is an inverted veffel, which exactly fits ano¬
ther, which is fixed within the cylinder B. " When it
is preffed down to the bottom of the cylinder, water
is poured in, by which means the fmall quantity of air
which remains in the intermediate fpaces, is forced out,
and the gas to be preferved may be introduced at the
lower Itop-cock C. The veffel A is nearly balanced
by the weights DD, which are connected with it by
means of the cords a a a a, which move on the pullies
bbbb. As the gas enters the apparatus, it forces up
the veffel A, and in this way it may be completely fil¬
led. It is forced out by turning the flop-cock E, and
preffing down the veffel A, and may be conveyed in¬
to a pneumatic apparatus, and received in jars by mean?
of the flexible tube F.
INDEX.
A.
jfl.CE'TA'IE of potato, N° 987
Acetic acid, hiftory of, 647
properties, 65Q
analyfis, 659
Acids, diftinftive charafler of, 436
importance, il,%
found in animal bodies, 2637
Adhefton, how it happens, 59
accounted for, 60
AJinity, hiftory of,
aflion of, explained, 30
limited, go
laws of, g2
force of, I06
examples of,
Albumen from eggs, 2596
aii •„UkS’ 2^11
Alchemijts, moft eminent of, 2c
Alchemy, hiflory of, ufeful, 3 x
declines, 28
not fruitful in difcoveries, 32
, the reafon, o-t
A/kali, calcined, T A T
lilicated,
Alkalies, origin of the name, 897
chara&ers, 898
Alum, hiftory of, 1418
preparation, i*
. properties, l420
Alumina, hiftory of, 1399
properties, 1401
gelatinous, j402
. ^res» H11
Alumina, fpongy, J402
Amber, jqo
Ambergris,
compofition of,
Ammonia, hiftory of,
properties,
compofition,
falls,
Ammoniac,
Amnios, liquor of,
properties,
compofition,
of the cow,
compolition,
Ammotic acid, properties of.
Animals, funftions of,
decompofition,
component parts,
Anime,
Antimony, hiftory of,
properties,
ufes,
Ants,
Apparatus defcribed,
Application of chemiftry to the arte
Argil,
Argillaceous earth,
Arfeniate of potato,
Arfenic acid, properties of,
aftion of water on,
affinities,
AJfafcetida,
Atmofphere,
component parts of,
conftitution,
changes,
1
2476 Atnwfpheric air, properties of, N° 357
2857 Azotic gas, difeovery of, 350
2858 Azotic gas, properties of, 352
1°9(5 combines with oxygen, 356
1098 B.
1102 Bacon's theory of heat, 161
1110 of Gilead, 2472
2491 Barytes, hiftory of, ,2j6
2753 properties, 12j8
2 754 falts, 1268
2 75 7 Bdellium, 2498
2760 Beecher''s elements, 43
2764 jSt’/zssofc'acid, hiftory of, 714
814 properties, 716
2529 component parts, 720
2572 affinities, 722
2581 Benzoin, 2489
2468 Bergmann’s explanation of affinity, 56
1675 Bezoards, . 286z
1678 Bile, properties of, 2664
*691 compofition, 2669
2878 Bifmuth, hiftory of,
265 properties, 1661
13 Bitter matter, 2416
1399 Black, Dr, on caloric, 2j2
fixed air, 38
987 Bltjlers, liquor of, 2764
612 Blood, properties, 2642
613 ferum, 264g
617 cruor, 26^3
2490 fibrina, 26^7
conftituents of, 2660
2155 inflammatory, 2663
2163 diabetic, ' 2663
2166 2?/W, liquid, what, 24IO
Bodies,
c
Bodies, capacities of, for caloric, IST° 2f i
Boerha'ive, his diftribution of bodies, 256
Boiling, 2 9
point conftant, 230
Bones, .
compolition,
of different animals,
of the teeth, 2729
of fifhes, 2872
Boracic acid, difcovery of, 566
preparation, 5^7
properties, 5^8
affinities, 574
Borate of lime, 1213
Borax, hiftory of, 1067
properties, 1069
ufes, io73
Bofcovich's theory of cohefion, 72
Brfliw and nerves, _ # 2802
Britain, chemiftry firft ftudied in, 36
Brugnatelli on combuftion, 325
Butter of antimony, 1685
of bifmuth, 1670
of zinc, *775
C.
Calamine,
Calces of metals,
Calomel,
Caloric, what,
Bacon’s theory of,
velocity of,
minute particles,
refle&ion,
rays of,
effe&s of,
modifications of,
elaftic fluids, effects on,
radiated,
refra£ted,
refle&ed,
Camel, urine of,
Cameleon, mineral,
Camphor,
Camphorate of potafh,
Camphoric acid, hiftory of,
properties,
affinities,
Cantharides,
Canton's pyrophorus,
Caoutchouc,
Carbonate of potaffi,
Carbone, nature of, explained,
Carbonic acid, formation of,
names of,
method of obtaining,
I - properties,
affinities,
fatal effedls of,
Cajlor,
Cavendifh, Mr, his experiments on
water,
Cerumen of the ear,
properties,
compofition,
1752
1518
I738
159
161
165
166
170
172
3°3
334
181
241
242
243
2698
1652
2441
1006
738
740
744
2875
144
2449
974
397
595
596
598
599
606
608
2856
389
2735
2736
2738
H E M I S T R
Cheefe, N° 2713
Chemijlry, definition of, I
importance of to man, 7
application of, to the arts, 13
an art among the Egyp¬
tians, 17
Greeks, 18
Phoenicians, 19
Chinefe, 20
Romans,
Chromate of potalh, 986
Chromic acid, difcovery of, 635
ufes, 641
Churning, procefs of, 2710
Cinnabar, 1701
Citrate of potalh, 1005
Citric acid found in fruits, 680
compounds of, 690
affinities, 691
Civet, 2855
Coagulation, caufe of, 2598
Cobalt, 1593
Cochineal, 2880
Cohejion, force of, 68
Newton’s theory of, 70
Defagulier’s, 71
Bofcovich’s, 72
Cold refledled, 272
accounted for, 273
Colour, 15°
Colouring matter, 2394
Columbate of potalh, 986
Columbia acid, difcovery of, 642
properties, 644
Columbium, hiftory of, *572
analyfis, !574
Combujlion, 15 5
Concretions, morbid, _ __ 2815
found in pineal
gland, 2816
fall vary, 2817
pulmonary, 2819
compolition of, 2821
biliary, 2822
urinary, 2828
properties of, 2830
conftituents, 2831
folvents, 2842
how ufed, 2843
gouty, properties of, 2846
aftion of alka¬
lies on, 2847
Copaiva, 2473
Copal, . 2469
Copper, hiftory of, 195^
ores, *959
properties^ 1961
alloys, 2005
Corrojive fublimate, *73^
Cow, urine of, 2697
Crabs eyes, 2882
Crawford, Dr, his method of afcer-
taining the capacity of bodies
for caloric, 262
Cruor of blood, 2653
• s 775
Cruor of blood contains albumen
and foda, N° 2654
iron, 2655
Cryjlallization accounted for, 82
by Newton, 83
Hauy, 84
Curd, 2712
of milk of different animals, 2721
Cutis or true Ikin, 2783
D.
Dalton on caloric, 269
Decompofition of animals, 2572
Defnition of chemiftry, I
Defaguliers on cohefion, 71
Detonation, wffiat, 337
Diamond, 397
found in the torrid zone, 399
form of, 400
properties, 401
produftion of its combuf¬
tion, 40a
a limple fubftance, 403
compared with charcoal, 404
Different affinities among bodies, 112
Digefion, 2548
nature of unknowm, 2552
Difcoveries of the alchemifts, 30
importance of, 39
Dragon's blood, 2467
Dropfy, liquor of, 2764
E.
Earths, properties of, 1165
F,jfeBs of light on metallic oxides, 151
caloric, *75
folubility, 100
Egg yields albumen, 2596
Eggs, 2863
Egyptians, their knowledge of che¬
miftry, 17
Elajlic fluids, 183
Elemi, 2471
of bodies, 41
Epidermis of the Ikin, 2781
Epfom fait, . 1343
Ether, formation of, 832
names, 833
fulphuric, 834
nitric, 844
muriatic, 853
Evaporation explained, 80
Euphorbiitm, 2489
Examples of affinity, 94
Excrement, 2867
Expanfon, 178
quantity of,- 202
ExtraBive matter, 2387
<e, humours of, 2730
of Iheep, 2731
human, 273 a
F.
Eat, 2628
Fermentation, acetous, 2310
vinous, 2300
panary, 23I3
Fihrina obtained from blood, 2612
Fibrin#
77(5
Fibritia obtained from mufcle,
properties,
compofition,
Flint and fteel, effedls of,
Flowers of bifmuth,
of zinc,
Finale of potafb,
lime,
Fluoric acid, hiftory of,
properties,
compofition,
affinities,
Fluidity^
owing to an increafe of ca¬
loric,
Fluids, elaftic,
Feet us, cruft on,
nature of,
Fourcroy'ls experiments on water,
France, chemiftry ftudied in,
Freezing mixture, how ufed,
FriBion,
Frigorific particles,
Fulminating gold,
mercury,
platina,
powder,
filver,
G.
G-albanum,
Gallic acid, properties of,
affinities,
Gamboge,
Gajes not luminous,
expand equally,
azotic,
nitrous oxide,
nitrous,
Gelatine,
Glafs of antimony,
Gold, hiftory of, ,
properties,
affinities,
falls,
fulminating,
alloys,
Glucina, hiftory of,
properties,
falls,
Gluten, properties of.
Good conductors, what,
ufe of,
Greeks, their knowledge of chemi-
Guinea pig, urine of,
Gum, properties,
diftillation of,
refins,
Gun-powder,
preparation,
nature of,
Guaiac,
H*
Mair and nails,
CHEMISTRY.
N° 2613
2614
2616
277
1661
1758
968
1208
560
562
564
565
207
212
IOX
2758
2759
392
37
275
290
271
2099
ini
2135
950
2048
2494
706
7*3
2497
*57
206
350
363
369
2584
1684
2077
2080
2088
2089
2099
2109
1465
1467
I473
2337
246
248
18
2700
2327
2331
2485
947
948
949
2474
Hair and nails, aCtion of acids on, N° 2810
diftillation of, 2809
compofition, 2814
Hartjhorn, 2852
Many's theory of cryftallization, 84
/fee/explained, 156
latent, 224
from condenfation, ^ 278
by friCtion, 284
animal, 2545
Hijlory of chemiftry, 16
Honey, . 2874
Hooke's theory of light, 312
Horn from ftreep, &c. 2851
Horfe, urine of, 2696
fulminating powder, *73*
Hulme's experiments on, 149
Hydrogen gas, hiftory of, 373
properties, 375
a remedy in difeafe, 378
Hyperoxymuriatic acid,
how obtained, 556
compofition of, 558
affinities, 559
I.
Ice, water in the ftate of,
Importance of chemiftry,
Injlammable fubftances,
names of,
hiftory,
properties,
conftituents,
Inflection of light,
Ink, black, how to make,
fympathetic,
Iridium examined,
Iron, hiftory of,
ores,
properties,
caft, its properties,
falls,
alloys,
Irvine, Dr, his confirmation of
Black’s theory,
Ivory from the elephant,
K.
Hermes,
Kirwan's method of eftimating the
force of affinity, no
objections to it by
Morveau and
Berthollet, 111
method of afeertaining the
quantity of water in
fulphuric acid,
Koumifs,
394
7
816
818
819
821
829
*35
1936
1608
2153
1880
1882
1884
1896
1903
1945
236
2850
2807
aCtion of water on, 2808
r ? * L.
Labdanum,
Lac,
Laccic acid, diffiovery of,
properties of,
Laliic acid, difeovery of,
properties of,
469
27I5
2466
2475
768
771
762
764
La&ic acid, affinities of,
Lana philofophica,
Lavoi/ier on caloric,
Laws of affinity,
Lead,
properties of,
falls of,
alloys of,
Ligaments,
Light, velocity of,
particles,
effeCts,
reflection of,
rays of,
inflection,
refraCtion,
tranfparency,
undulating fluid,
Limbourg's idea of affinity,
Lime, properties of,
affinities,
falls,
Liquid, water in the ftate of,
Liquor filicum,
of the amnios,
properties,
of dropfy,
blifters,
Litharge,
M.
Magiflery of bifmuth,
Magnefla, hiftory of,
properties,
ufes,
Malate of potafh,
Malic acid, hiftory of,
properties,
Manganefe, hiftory of,
ores,
properties,
oxides,
Maflic,
Matter, folid,
fluid,
Mayow's theory of light,
Medicine,
Mellitic acid, difeovery of,
properties,
compofition,
Membranes,
Mercury, hifto.ry of,
analyfis,
properties,
affinities,
fulminating,
Metals, importance of,
brilliancy,
denfity,
duCtility,
fufibility,
imperfeCt,
perfeCt,
Milk, properties of cow’s,
feparates into two parts,
coagulation of,
N® 767
1736
264
92
1824
1827
i839
1869
2801
130
*33
151
134
152
13*
136
140
128
55
1169
H75
1181
395
1450
2753
2754
2764
ib.
1834
1669
*332
I334
1340
J005
692
696
1632
1633
i635
1637
2464
75
76
3*3
9
754
756
760
2799
1700
1702
1705
1716
1731
1504
1506
1509
1C12
J5i5
1529
ibid.
2706
2707
2711
Milk,
Milh, ferments, N° 2715
compofition, 27I7
comparifon of different kinds, 2719
Millepedes, 2876
Mineral cameleon, 1652
waters, claffes of, 2194
gafes, 2200
falts, 2204
analyfis, 2207
Minerals, 9
Mixture, fource of, 291
Mixtures, freezing, 274
Molybdate of potafh, 985
Molybdena, hiftory of, 1555
properties, J557
Molybdic acid, hiftory of, 627
properties, 628
Mother of pearl, 2884
Mucus of the nofe, 2735
Muriate of potafh, ufes of, 958
properties, 960
compofition, 966
lime, 1298
Muriatic acids, names of, 525
properties, 528
fuppofed formation
of, 537
ufes, _ 539
affinities, 541
Mufcles, ftrufture of, 2788
compofition, 2792
boiled, 2794
roafted, 2 79?
properties, 2798
Mute, 2854
Myrrh, 2492
N.
Narcotic matter, 2418
Natural hiftory, 3
philofophy, 4
Newton’s theory of cohefion, 70
cryftallization, 83
Nickel, hiftory of, 1615
properties, 1618
alloy of, 1624
Nitrate of potafh, properties, 942
ufes, 954
Nitric acid, names of, 497
hiftory, 498
properties, 502
abforbs water, 504
Nitrous gas, how prepared, 369
properties of, 370
combines with oxygen, 372
oxide gas, _ _ 363
properties of, 365
tafte and fmell of, 567
Nomenclature, new, 40
O.
Ochroit earth, analyfis of, 2887
combines wdth car-
bone, 2889
characters of, 2890
Oils, of two kinds, 861
Vol. V. Part II.
H E M I S T R
Oils, fixed, preparation of, N'
A properties,
compofition,
rancidity,
ufes,
volatile, characters of,
fragrance,
fluidity,
tafte,
ufes,
Olibanum,
Opobalfamum,
Opoponax,
Ofmium,
Oxalate of potafh,
Oxalic acid found in plants,
properties of,
component parts,
affinities,
Oxidation,
Oxide,
Oxygen, difeovery of,
how obtained,
properties,
effeCts of, in combuftion,
animals live in,
combines with bodies,
P.
Palladium, properties of,
Paracelfus, account of,
Particles, frigorific,
Pearl,
white,
PercuJJion, fource of caloric,
Pewter,
Philofophers ftone,
Phofphate of lime,
ammonia,
Phofphorous acid,
properties, 586
compofition, 592
affinities, 594
Phoenicians, 2 3
Phlogijlon, fuppofed to be light, 315
hydrogen gas, 426
Phofphoric acid, properties of, 576
Phofphorus, hiftory of, 415
exifts in bones, 416
how obtained, 417
purified, 418
combuftion of, 424
combines with azote, 425
PiElet on caloric, 257
experiments, 271
Pinchbeck, 2014
Pitch, 2463
Plates, explanation of, Page 773
Platina, properties of, 2126
falts, 2132
fulminating, 2135
alloys, 2136
Potaflo, names of, 900
preparation, 901
purification, 904
properties, 908
864
866
868
872
877
879
883
884
887
894
2487
2472
2496
2154
992
663
665
668
669
1517
363
341
343
345
346
347
348
2148
26
271
2885
1669
277
1822
23
2834
2835
Y.
Potajh, ufes of,
Poivder, fulminating,
Priejlley on air,
on water,
Propolis,
PruJJic acid, hiftory of,
difeovery,
examined by
N1
Macquer,
Bergman,
Scheele,
properties,
affinities,
Pus, nature of,
how to diftinguifh,
Pyrites,
Pyrophorus of Canton,
Quicklime,
filver,
Q,
R.
Rabbits, urine of,
Radiation not the only caufe of cool¬
ing,
Rays, folar, of three kinds,
coloured and heated,
invifible,
Red precipitate,
RejleSlion of light,
RefraBion
ReJleBion of caloric,
Repuljion
RefraBion
Rejins, vegetable,
from bile,
Refpiration,
changes on the air,
blood,
Rofacic acid, origin of,
properties,
Rojin,
S.
SacIaBic acid, hiftory of,
Sagapenum,
Saliva, properties of,
compofition,
of the horfe,
Sandarac,
Sarcocol,
Saturation, what,
Scales,
Scammony,
Sea water, properties of,
Sebacic acid, properties of,
Secretions, morbid,
Semen, properties of,
compofition,
Serum of blood,
contains gelatine,
fulphur,
falts,
Sheep, eyes of,
Shells,
of egg, _
Silica} properties oi,
5 ?
777
5 913
95°
3*7
388
2873
774
77*
779
, 781
783
796
8oi
2764
3769
1901
144
1700
2699
254
301
*73
174
1728
*34
136
170
169
171
2457
2fi33
2530
2536
2541
811
813.
2462
73i
2495
2723
2727
2728
2465
2493
124
2871
2488
2186
804
2764
2 744
2753
2649
2650
2651
273I
2883
2864
1446
Silk,
7/8
Si/k,
Silver, hiftory oF,
ores,
analyfis,
falts,
alloys,
fulminating,
Skin, epidermis of,
cutis,
rete mucofum,
Smell, earthy,
Soda, names of,
purification,
falts,
SpeBrum,
Spermaceti, properties ofr
Stahl improves Beecher’s theory,
Starch, properties of,
Steam, nature of,
caloric of,
Storax,
Stomach, membrane of,
Strontites, hillory of,
properties,
falts,
Suber,
Suberate of potalh,
Suberic acid, properties of,
Succinic acid, hiftory of,
properties,
Sugar, manufacture of,
properties,
component parts,
Sulphuric acid, properties,
purification,
Sulphurous acid, hiftory of,
Sulphur, properties,
Sun, chief fource of light,
Styrax,
Synovia,
T.
'Tables of affinity invented,
enlarged,
lan
Tartaric acid, hiftory of,
properties,
component parts,
affinities,
Tartrate of potaffi,
Tears,
properties,
compofition,
Teeth, bones of,
enamel of,
Tellurium, hiftory of,
properties,
adlion of alkalies on,
metals,
Temperature, change of,
Tendons,
Thermometer,
conftruftion of.
C H E M I S
N° 2879 Fahrenheit’s,
2023 Reaumur’s,
2024 Celfius’s,
2025 Delifte’s,
2035 Tin, hiftory of,
2067 ores,
2048 properties,
2781 affinities,
2783 falts,
2787 alloys,
1401 Tinfoil,
1018 Tinning, procefs of,
1022 Tinplate,
1030 Titanium, properties,
137 Toad,
2860 Tortoife,
34 Tungjlate oi. potefa,
23^5 Tungjlen, properties,
228 alloys,
237 Tungflic acid, hiftory,
2482 properties,
2867 Turpeth mineral,
1312 nitrous,
I3I4 . U.
1319 Vniverfal medicine,
2515 Uranium, difeovery of,
1012 hiftory of,
747 properties,
723 Urate of ammonia,
Urea how obtained,
properties,
compofition,
Uric acid, hiftory of,
properties,
found in urinary calculi,
2338
2340
2346
465
464
479
433
!54
2481
2739
52
53
2504
670
673
678
679
997
2735
2733
2734
2779
ib,
1692
1693
1696
1698
163;
2800
194
203
T R
N° 198
199
200
201
1787
1788
1790
1799
1800
J817
179°
19 c6
*955
*5I7
2869
2870
984
I55I
*554
618
620
1720
1728
Urine,
properties,
component parts,
products by fpontaneous de-
compofition,
of the horfe,
cow,
camel,
rabbit,
Guinea pig,
24
1586
7587
1589
2833
2617
2618
2620
806
809
2832
2^70
2686
2687
2696
2697
2698
2C99
2700
graminivorous animals, 2701
carnivorous,
birds,
turtle,
• V.
Vapour, elafticity of,
water in the ftate of,
Varmjh, copal,
amber,
Vegetables, root of,
bark,
pith,
veffels,
germination,
food,
leaves,
decorapofition,
2702
2703
2704
239
396
2470
2479
2257
2258
2260
2 262
2263
2270
2284
2298
Y.
Vegetable acids,
Velocity of light,
difeovered,
confirmed,
caloric,
Vermilion,
Vinous fermentation,
Nc
2354
130
131
132
240
1701
2300
Viper, poifon of,
W.
phenomena of, 2302
2868
Water, adhefion of to glafs,
bulk increafed by freezincr
effeas of, 6‘
compofition,
conjeaures concerning,
Prieftley’s experiments on,
Cavendilh’s
Watt’s
Lavoifier’s,
Fourcroy’s
in the ftate of ice,
liquid,
vapour,
Wax,
of the ear,
compofition,
Wedgewood's pyrometer,
V hey from milk of difterent animals, 2722
IVilcke, Mr, his method of afeertain-
ing the capacity of bodies for
caloric,
Wood,
conduas caloric.
Wool,
Y.
folk of egg,
compofition of,
Tttria, hiftory of,
properties of,
fulpkate of,
nitrate of,
phofpbate of,
carbonate of.
64
188
190
384
387
388
389
390
39*
392
394
395
396
2432
2736
2738
1412
263
2499
2 CO
2853
2865
2866
*457
*459
1460
1462
1463
1464
Z.
Zinc, hiftory of,
properties of,
phofphuret of,
fulphuret of,
fulphate of,
fulphite of,
nitrate of,
muriate of,
phofphate of,
carbonate of,
acetate of,
aaion of alkalies on,
Zirconia, hiftory of,
properties,
affinities,
falts,
Zoophytes,
1751
*754
1760
1762
1764
1768
*773
*775
*777
1778
1779
1780
1484
i486
1490
1492
2886
CHEMNITZ,
C H E
Oiemnitz CHEMNITZ, Martin, a famous ^umeran di-
Cherem, .Vin®’ tn® dl‘clPle.of Melandhon, was born at Britzen
Brandenburg, in 1522. He was employed in feveral
important negociations by the princes of the fame
commumon; and died in 1589. His principal work
'S CMMOSH I C%Unci‘ °f Trent- in Latin.
L.HLMOSH. See Chamos.
CH LMOolS, a difeale of the eyes, proceeding from
an mnammatmn j wherein the white of the eye fwells
above the black, and overtops it to fuch a degree
that there appears a fort of gap between them. Others’
dehne it to be an elevation of the membrane which
fm rounds the eye, and is called the white; being an
alfection of the eye, like white tlefh. S
CHENOPODIUM, Goose-Foot, or Wild Orach:
See Botany Index. '
CHEPELIO, an ifland in the bay of Panama and
province of Darien, in South America, fituated about
three leagues from the city of Panama, which it fup-
plies with provifions. W. Long. 81. N. Lat o ^
• CHEPSTOW, a market town ®f Monmouthlhire
n England, feated on the river Wye near its mouth,
in W. j.ong. 2. 40. N. Lat. 51. 40.
CHEQ^ ov Cherif, the prince of Mecca, who is,
f-V 7\\\htrTe« °f the law’ and fovereign pon-
ti.Fof all the Mahometans of whatever feft or country
they be. See Caliph. j
1 he grand figmor, fophis, moguls, khans of Tarta-
ry, See lend him yearly prefents, efpecially tapellry to
cover Mahomet’s tomb withal, together with a fump-
tuous tent for himfelf, and vaft fums of money to pro-
dclltfon 311 the Pllgnms durinS the J7 days of their
CtlERASCO, a ftrong and confiderable town of
Italy, in Piedmont, and capital of a territory of the
ame name, with a Prong citadel belonging to the
kmg of Sardinia, where he retired in 1706, during
the fiege of Turin. It is feated at the confluence of
tue rivers Sturia and Tanaro, upon a mountain. E
Long. 7. 55. N. Lat. 44. 35.
CHERBURG, a fea port town of France, in Nor¬
mandy, with a harbour and Auguftine abbey. It fs
remarkable for the fea-fight between the Englilh and
I rench fleets m 1692, when the latter were beat, and
upwards of twenty of their men of war burnt near
Cape la Hogue. The Britilh landed here in Auguft
1758, and took the town, with the fhips in the bafon,
demolilhed the fortifications, and ruined the other
works which had been long carried on for enlarging
the harbour and rendering it more fafe and conveni¬
ent. Within theie few years it has been attempted
again to improve the harbour, and rebuild the works •
but after confiderable progrefs had been made, a great
part of them fuddenly gave way, and the enterprife it
is thought will not be again refumed. E. Long 1 28
N. Lat. 49. 38. ^ 6' * ^
CHER EM, among the Jews, is ufed to fignify a
ipecies of annihilation. See Annihilation.
I he Hebrew word cherem, fignifies properly to de-
Jlroy, exterminate, devote, or anathematife.
. Cherem is likewife fometimes taken for that which
is confecrated, vowed, or offered to the Lord, fo that
it may no longer be employed in common or profane
tiles No devoted thing that a man fhall devote unto
ne Lord, of all that he hath of man and beaft, and
r t 779 ] CHE
Lutheran d- of the field of hi, polTeffion, (hall be fold or redeemed •
every devoted ,lung is tnoft holy to the Lot d "one
devoted winch fhall be devoted of men, lhall be
deemed, but (hall furely be put to death. There are
toT ^ert ‘W11' Pf-rf0ns th“s d»-«ed were put
example.’ “ 3
!" 3I"onR‘be^Jewt 'see ‘^“^““““Lation
• ;KESOUL,or Chahrzul, a town of Turkey
n Alta, capital of Curdiilan, and the feat of a begle7
CHERn0?K 45i 'l N' Lat' °-
ILRi.LFS’ ?amos’ a Greek poet, (louriflied
bv dteTth 'ftv HefUnS viftoty gained
y t e Athenians over Xerxes, and was rewarded with
Te l |° d for CV"T verfe. His poem had after.
rrtLfHorer.1 °f with the
See Botany Index.
HERLEbQUIOR, in Turkifh affairs, denotes a
CHERMES "•1 °7th; gra"d fign!°r’s aimi's-
• „ tn '"Zoojogy, a genus of infeas belong.
eoGv i,2v° hemiP"‘a- See Eutomo.
Chermes Mineral. See Kermes.
gHERRY-isLAND, an illand in the northern ocean t
lying between Norway and Greenland, in E. Lon".
20. 5. N. Lat. 75. q. 0
Prunus» Botany Index.
CHLRSO, an ifland in the gulf of Venice, with
a town, of the fame name nearfcCroatia, belonging to
ne Venetians. The air is good, but the foil ffonv :
however, it abounds m wine, cattle, oil, and excellent
honey. E. Long. 15. 5. N. Lat. 4c. 8.
. fiERSONESUS, among modern geographers
t e fame with a pemnfula ; or a continent almoft en-
compaffed round with the fea, only joining to the main
land f by a narrow neck or ifthmus. The word is
Greek 5 °f ^ W, and ijland.
, h hgmfies the fame. In ancient geography, it
vas applied to feveral penmfulas 5 as the Cherfone-
us Aurea, Cimbnca, Taurica, and Thracica, now
Romania10 ^ Ma aCC3’ Jutland> Crim Tartary, and
CHERT Petro si LEX, Lafiis Cornetts, the Horn-
See Index.
1 1 a market town of Surrey in Eng.
End, about feven miles weft from Kingfton upon
Thames. W. Long. 30. N. Lat. 31. 25. F
CHERUB, (plural, Cherubim) ; a celeftial fphit
7 is placed neM ,0 ,l1'
1 he term cherub, in Hebrew, is fometimes taken for
a call or ox. Ezekiel fets down the face of the cherub
as fynonymous to the face of an ox. The word chemh,
• ^yrlac and Cha]dee, fignifies to till or plow, which
is the proper work of oxen. Cherub alfo fignifies
Jlrong -Mid powerful. Grotius fays, that the cheru-
him were figures much like that of a calf. Bochart
inks likewife, that the cherubim were more like to
the figure of an ox than to any thing befides j and
Spencei is of the fame opinion. Laftly, St John, in
the Revelation, calls cherubim beafrs. jofephus fays
be cherubim were extraordinary creatures, of a figure
unknown to mankind. Clemens of Alexandria*be-
5 F 2 lieves,
Cheretn
li
Cherub,
* - ii 1 1 /
C H E [ 780 ] C ^
Chervil' UeveMlrat .he Egyp,ia„S inrl.a.ed .W ^ of .nd -ft defe.v.ng man .n .he
!1 the Hebrews in the reprefentations of their fph
GhefelJen. and their hieroglyphical animals. All the feveral de-
fcriptions, which the fcripture gives us of cherubim
differ from one another; but all agree m reprefent g
them as a figure compofed of various creatures, as a
and a lion. Such were the
Thofe which Ifaiah
had the
man, an ox, an eagle. ^
cherubim defcribed by Ezekiel. 1 j c
faw, and are called feraphim by him, had the figure
of a man with fix wings ; with two whereof t ey
covered their faces, with two more they covered their
feet, and with the two others they flew I hole
which Solomon placed in the temple at Jerufalem are
fuppofed to have been nearly of the fame form. 1 hole
which St John defcribes in the Revelations were all
eyes before and behind, and had each fix wings. 1 he
£rft was in the form of a lion, the fecond m that of a
calf, the third of a man, and the fourth of an eagle.
The figure of the cherubim was not always uniform,
fince they are differently defcribed in the fhapes of men,
eagles, oxen, lions, and in a compofition of all thefe
figures put together. Mofes likewflfe calls theie fym-
bolical or hieroglyphical reprefentations, which were
embroidered on the veils of the tabernacle, cherubim oi
coftly work. Such were the fymbolical figures which
the Egyptians placed at the gates of their temples and
the images of the generality of their gods, which weie
commonly nothing but fiatues compofed of men and
animals.
CHERVIL. See Ch.erophyi.lum, Botany in-
dcx •
CHESAPEAK, in America, one of the largeft
bays in the known world. Its entrance is between
Cape Charles and Cape Henry in Virginia, 12 miles
wide •, and it extends 270 miles to the northward,
dividing Virginia and Maryland. Through this ex¬
tent it is from 7 to 18 miles broad, and generally about
9 fathoms deep ; affording many commodious har¬
bours, and a fafe and eafy navigation. It receives the
waters of the Sufquehannah, Potomak, Rappahan¬
nock, York, and James rivers, wdiich are all large and
navigable.
CHESELDEN, William, an eminent anatomifl
and futgeon, was born at Burrow on the Hill, in the.
county of Leicefter, defcended from an ancient family
in the county of Rutland, whofe arms and pedigree
are in Wright’s “ Eliftory of Rutland.” He received
the rudiments of his profefjfional fkill at Leicefter j
and married Deborah Knight, a citizen’s daughter,
by whom he had one daughter, Williamina Deborah.
In 1713 he publifhed his Anatomy of the Human
Body, one volume 8vo ; and in 1723, A Treatife on
the High Operation for the Stone. He was one of
the earlieft of his profeffion who contributed by his
writings to raife it to its prefent eminence. In the
beginning of 1736, he was thus honourably mention¬
ed by Mr Pope : “ As foon as I had fent my laft
letter, I received a mod; kind one from you, ex¬
prefling great pain for my late illnefs at Mr Chefel-
den’s. I conclude you was eafed of that friendly ap-
prehenfion in a few days after you had difpatched
your’s, for mine muft have reached you then. I wmn-
dered a little at your query, Who Chefelden was ? It
fhows that the trueft merit does not travel fo far any
way as on the wings of poetry ; he is the moft noted
E
     whole profeflion of Chefliire,
cWrurgei-yT^nd has laved the lives of thoufands by , _chefn_el...
his manner of cutting for the ftone.” He Appears to
have been on terms of the molt intimate inendfhip
with Mr Pope, who frequently, in his Letters to Mr
Richardfon, talks of dining with Mr Chefelden, who
then lived in or near Queen Square. In February
1737, Mr Chefelden was appointed furgeon to Chel-
fea hofpital. As a governor of the Foundling Hof-
pital, he fent a benefaftion of 5pl._to that charity.
May* 7. 1751, inclofed in a paper with the following
lines :
’Tis what the happy to th’ unhappy owe *,
For what man gives, the gods by him beftow. Pope.
He died at Bath, April 11. 1752, of a diforder ari-
fing from drinking ale after eating hot buns. Finding
himfelf uneafy, he fent for a phyfician, who adviled vo¬
miting immediately and if the advice had been taken,
it was thought his life might have been faved. By his
diredlion, he wTas buried at Cheliea. r t? 1 j
CHESHIRE, a maritime county of England,
bounded by Lancafhire on the north ; Shropfhire and
part of Flintfhire, on the fouth ; Derbyfhire and Staf-
fordfhire, on the eaft and fouth-eaft •, and Denbigh-
ftvire, and part of Flintfhire, on the weft and north-weft.
It extends in length about 44 miles, in bieadth 25 >
and is fuppofed to contain 125,000 inhabitants. Both
the air and foil in general are good. In many places
of the country are peat-mofles, in which are often
found trunks of fir-trees, fometimes feveral feet under
ground, that are ufed by the inhabitants both for fuel
and candles. Here alfo are many lakes and pools well
ftored with fifh ; befides the, rivers Merfey, Weaver,
and Dee, which laft falls into a creek of the Irifti fea
near Chefter. This county alfo abounds with wood :
but what it is chiefly remarkable for, is its cheefe,
which has a peculiar flavour, generally thought not^ to
be inferior to any in Europe } (fee Cheese). T. he
piincipal towns are, Chefter the capital, Cholmondely,
Namptwitch, &c.
William the Conqueror erefted this county into a
palatinate, or county-palatine, in favour of his nephew
Hugh Lupus, to whom he granted the fame Sovereign¬
ty and jurifdidfion in it that he himlelf had in the reft
of the ifland. By virtue of this grant, the town of
Chefter enjoyed fovereign jurifdidlion within its own
precin&s *, and that in fo high a degree, that the earls
held parliaments, confifting of their barons and tenants,
which wrere not bound by the a£ls of the Englifh pai-
liament: but the exorbitant power of the palatinates
was at laft reduced by Henry VIII. } however, ad.
cafes and crimes, except thofe of error, foreign plea,
foreign voucher, arid high-treafon, are Hill heard and
determined within the ftiire. The earls were ancient¬
ly firperiors of the whole county, and all the land¬
holders were mediately or immediately their vaflals,
and under the like fovereign allegiance to them as
they were to the kings of England } but the earldom
was united to the crown by EdwTard HI. fince which
time, the eldeft fons of kings of England have always
been earls of Chefter, as well as princes of Wales.
Chefliire fends four members to parliament } two for
the county, and tw7o for the capital.
CHESNE, Andrew dv, ftykd the father of French
hiftory.
CHE [ 781 ] CHE
Chefnut- hiftory, was born in 1584. He wrote, 1. A hiftory
tree, of the popes. 2. A hiltory of England. 3. An in-
Chefs. qUiry into the antiquities of the towns of France. 4.
hiftory of the cardinals. 5. A bibliotheca of the
authors who have written the hiftory and topography
of France, &c. He was crufhed to death by a cart,
in going from Paris to his country houfe at Verriere,
in 1640.
CHESNUT-tree. See Fagus, Botany Index.
CHESS, an ingenious game performed with differ¬
ent pieces of wood, on a board divided into 64 fquares
or houfes •, in which chance has fo fmall a lhare, that
it may be doubted whether a perfon ever loft a game
but by his own fault.
Each gamefter has eight dignified pieces, viz. a
king, a queen, two bifhops, two knights, and two
rooks, alfo eight pawns: all which, for diftindtion’s
fake, are painted of two different colours, as white
v and black.
As to their difpofition on the board, the white
king is to be placed on the fourth black houfe from
the corner of the board, in the firft and lower rank ;
and the black king is to be placed on the fourth
white houfe on the oppofite, or adverfary’s, end of the
board. The queens are to be placed next to the
kings, on houfes of their own colour. Next to the
king and queen, on each hand, place the two bifhops j
next to them, the, two knights *, and laft of all, on
the corners of the board, the two rooks. As to the
pawns, they are placed, without diftindlion, on the
fecond rank of the houfe, one before each of the dig¬
nified pieces.
Having thus difpofed the men, the onfet is com¬
monly begun by the pawns, which march flraight for¬
ward in their own file, one houfe at a time, except
the firfl move, when it can advance two houfes, but
never moves backwards : the manner of their taking
the adverfary’s men is fidewife, in the next houfe
• forwards ; where having captivated the enemy, they
move foward as before. The rook goes forward or
crofswife through the whole file, and back again.
The knight fkips backward and forward to the next
houfe, fave one, of a different colour, with a fideling
march, or a Hope, and thus kills his enemies that fall
in his tvay, or guards his friends that may be expofed
on that fide. The bifhop walks always in the fame
colour of the field that he is placed in at firft, forward
and backward, aflope, or diagonally, as far as he lifts.
The queen’s walk is more univerfal, as fhe takes all
the fteps of the before-mentioned pieces, excepting
that of the knight ; and as to the king’s motion, it is
one houfe at a time, and that either forward, back¬
ward, floping, or fidewife.
As to the value of the different pieces, next to the
king is the queen, after her the rooks, then the bi¬
fhops, and laft of the dignified pieces comes the knight.
The difference of the worth of pawns, is not fo great
as that of noblemen 5 only, it muft be obferved, that
the king’s bifhop’s pawn is the beft in the field, and
therefore the fkilful gamefter will be careful of him.
It ought alfo to be obferved, that whereas any man Chefs,
may be taken, wThen he falls within the reach of any v""""
of the adverfary’s pieces, it is otherwdfe with the king,
who, in fuch a cafe, is only to be faluted with the
wmrd check, warning him of his danger, out of which*
it is abfolutely neceffary that he move ; and if it fo
happen that he cannot move without expofing himfelf
to the like inconveniency, it is check-mate, and the
game is loft. The rules of the game are,
1. In order to begin the game, the pawms muft be
moved before the pieces, and aftenvards the pieces muft
be brought out to fupport them. The king’s, queen’s,
and biihop’s pawns, ftiould be moved firft, that the
game may be well opened 5 the pieces muft not be
played out early in the game, becaufe the player may
thereby lofe his moves : but above all, the game
fhould be well arranged before the queen is played
out. Ufelels checks fhould alfo be avoided, unlefi?
fome advantage is to be gained by them, becaufe the
move may be loft, if the adverfary can either take or
drive the piece away.
2. If the game is crowded, the player will meet with
obftruftions in moving his pieces j for which reafon
he fhould exchange pieces or pawns, and caftle (a)
his king as foon as it is convenient, endeavouring at
the fame time to crowd the adverfary’s game, which
may be done by attacking his pieces with the pawns,
if the adverfary fhould move his pieces out too foon.
3. The men fhould be fo guarded by one another,
that if a man fhould be loft, the player may have it in
his power to take one of the adverfary’s in return j
and if he can take a fuperior piece in lieu of that
which he loft, it would be an advantage, and diftrefs
the adverfary.
4. The adverfary’s king fhould never be attacked
without a force fufficient ; and if the player’s king
fhould be attacked without having it in his power to
attack the adverfary’s, he fhould offer to make an ex¬
change of pieces, which may caufe the adverfary to
lofe a move.
5. The board fhould be looked over with attention,
and the men reconnoitred, fo as to be aware of any
ftroke that the adverfary might attempt in confequence
of his laft move. If, by counting as many moves for¬
ward as poflible, the player has a profpedl of fuccefs,
he fhould not fail doing it, and even facrifice a piece
or twm to accomplifh his end.
6. No man fhould be played till the board is tho¬
roughly examined, that the player may defend him¬
felf againft any move the adverfary has in view' 5 * ei¬
ther fhould any attack be made till the confequences
of the adverfary’s next move are confidered ; and when
an attack may with fafety be made, it ftrould be pur-
fued without catching at any bait that might be thrown
out in order for the adverfary to gain a move, and
thereby caufe the defign to mifcarry.
7. The queen fhould never ftand in fuch a manner-
before the king, that the adverfary, by bringing a
rook or bifhop, could check the king if fhe W’ere not
there : as it might be the lofs of the queen.
8. The
(a) Caftle his king, is to cover the king with a caftle } which is done by a certain move which each player
has a right to whenever he thinks proper.
Chefs.
CHE [ 7S
8. The adverfary’s knight fliould never be fuffered to
check the king and queen, or king and rook, or queen
and rook, or the two rooks at the fame time 5 efpe-
cially if the knight is properly guarded : becaufe, in
nhe two firft cafes, the king being forced to go out of
check, the queen or the rook muit be loll ; and in the
two laft cafes a rook muft be loft at leaft for a worfe
piece.
9. The player fliould take care that no guarded
pawn of the adverfary’s fork two of his pieces.
10. As foon as the kings have caftled on different
fides of the board, the pawns on that fide of the board
ftiould be advanced upon the adveifary’s king, and the
pieces, efpecially the queen and rook, fhould be brought
to fupport them } and the three pawns belonging to
the king that is caftled muft not be moved.
11. The more moves a player can have as it were
in ambufcade, the better ^ that is to fay, the queen,
biiliop, or rook, is to be placed behind a pawn or a
piece, in fuch a pofition as that upon playing that
pawn or piece a check is difeovered upon the adverfa¬
ry’s king, by which means a piece or fome advantage
is often gained.
12. An inferior piece fiiould never be guarded
with a fuperior, when a pawn would anfwer the fame
purpofe j for this reafon, the fuperior piece may re¬
main out of play ; neither fhould a pawn be guarded
with a piece when a pawn would do as well.
13. A well fupported pawn that is paffed often cofts
the adverfary a piece 5 and when a pawn or any other
advantage is gained without endangering the lofs of
the move, the player fhould make as frequent ex¬
changes of pieces as he can. The advantage of a paf¬
fed pawn is this : for example, if the player and his
adverfary have each three pawns upon the board, and
no piece, and the player has one of his pawns on one
ude 01 the board, and the other two on the other fide,
and „the adverfary’s three pawns are oppofite to the’
player’s twro paivns, he fhould march with his king as
loon as he can, and take the adverfary’s pawns : If
the adverfary goes with his king to fupport them, the
player fhould go on to queen with his Angle pawns :
and then if the adverfary goes to hinder him, he fhould
take the adverfary’s pawns, and move the others to
queen (b).
14. When the game is near finifhed, each p^rty
having orny three or four pawns on each fide of the
noard, the_kings muft endeavour to gain the move in
order to win the game. For inftance, when the play¬
er , mgs his King oppofite to the adverfary’s with on¬
ly one fquare between, he will gain the move.
15. If the adverfary has his king and one pawn on
! board and the player has only his king, he can¬
not lofe the game provided he brings his king oppo¬
fite to the adverfary’s, when the adverfary is direaiy
before or on one fide of his pawn, and there is only
one fquare between the kings. ^
16. If the adverfary has a bifhop and one pawn on
2 ] CHE
toe rook’s line, and this bifhop is not of the colour
that commands the corner fquare the pawn is goinp-
to, and the player has only his king, if he can get
into that corner, he cannot lofe j but, on the conUa-
ry, may win by a ftale (c).
17. If the player has greatly the difadvantage of the
game, having only his queen left in play, and his king
happens to be m a pofition to win, as above-mention¬
ed, he fhould keep giving check to the adverfary’s
king, always taking care not to check him where he
can interpole any of his pieces that make the ftale •
by lo doing he will at laft force the adverfary to take
his queen, and then he will win the game by being in
a ftale-mate.
18. 1 he player fhould never cover a check with a
piece that a pawn pufined upon it may take, for fear of
getting only the pawn in exchange for the piece.
19. A player fliould never crowd his adverfary up
with pieces, for fear of giving a ftale-mate inadver¬
tently, but always fliould leave room for his king to
move. 6
By way of corroborating what has been already faid
with refpeft to this game, it is neceffary to warn a
player againft playing a timid game. He fhould never
be too much afraid of lofing a rook for an inferior
piece j becaule although a rook is a better piece than
any other except the queen, it feldom comes into play
to be of any great ufe till at the end of the game 5 for
which reafon it is often better to have an inferior piece
in play, than a fuperior one to ftand ftill, or moving
to no great purpofe. If a piece is moved, and is im
mediately drove away by a pawn, it may be reckoned
a bad move, becaufe the adverfary gains a double ad¬
vantage over the player, in advancing at the fame
time the other is made to retire 5 although the firft;
move may not feem of confequence between equal
players, yet a move or two more loft after the firft
makes the game fcarcely to be recovered.
neVCr wants for variety at this game, pro¬
vided the pieces have been brought out regularly : but
if otherwife, it often happens that a player has fcarce
any thing to play.
Many indifferent players think nothing of the
pawns, vyhereas three pawns together are ftrong : but
four, which conftitute a fquare, with the afliftance of
other pieces, . well managed, make an invincible
ftrength, and m all probability-may produce a queen
when very much wanted. It is true, that two pawns
with a fpace between are no better than one ; and if
there fhould be three over each other in a line the
game cannot be in a worfe way. This fhtnvs that the
pawns are of great confequence, provided they are
kept clofe together. y
Some middling players are very apt to rifle lofing
the game m order to recover a piece : this is a mif-
take ; for it is much better to give up a piece and at¬
tack the enemy in another quarter ; by fo doing, the
player has a chance of fnatching a pawn or two from.
Chefs.
at thii game when the odgbal^ne"s’loft? ^ ^ m0Ve & PaWn int° the adverfary’s back row, which is the rule
V-) When the king is blocked up fo as to have no move at all.
2
CHE [ ;
Chet, or gaining fome advantage over, the adverfarv, whilft
“"'•t'-™' ‘ his attention is taken up in purfuing this piece*.
If the queen and another piece are attacked at the
fame time, and that by removing the queen the piece
mart be loft j provided two pieces can be gained in
exchange for the queen, the queen fhould be given
up, it being the difference of three pieces, and confe-
quently more than the value of the queen. By lofmg
the queen, the game is not thrown "into that diforder
which it would otherwife have been ; in this cafe it
would be judicious to give the queen for even a piece,
or a pawn or two ; it being well known among good
players, that he who begins the attack,-and cannot
maintain it, being obliged to retire, generally lofes
the game.
A player (hould never be fond of changing without
reafon, becaufe the adverfary, if he is a good player,
vs ill ruin his fituation, and gain a considerable advantage
over him. But rather than lofe a move, when a player
is Stronger than the adverfary, it is good play to change,
for he thereby increafes his Strength.
When the game is alrnolt drawn to a conclufion,
the player Should recolleft that his king is a capital
piece, and confequently Should keep him in motion;
by io doing, he generally gets the move, and often the
game.
As the queen, rook, and bifhop, operate at a di-
ftance, it is not always neceffary in the attack to have
them near the adverfary’s king.
If a man can be taken with different pieces, the
plaver ihouid take his time, and conlider which of
thofe pieces is the beft to take it with.
If a piece can be taken almofl at any time, the
player Should not be in a hurry about it, but try to
make a good move elfewhere before he take it.
A player Should be cautious how he takes his adver-
farv’s pawn with his king, as it often happens to be a
fafeguafd to it.
After all that has been Said, it is ftill neceSfary for
us to advife thofe who would play well at this game,
to be very cool and attentive to the matter in queftion :
for it is impoffible that any perfon in the univerfe can be
capable of playing at chefs if their thoughts are em¬
ployed elfewhere. The laws at this game are,
1. If a player touches his man, he muft play it ; and
if he quits it, he cannot recal it.
2. If by miftake or otherwife a falfe move is played,
and the adverfary takes no notice of it till he hath
played his next move, it cannot be recalled by either of
the parties.
3. If a player mifplaces the men, and he plays two
moves, it is at the option of the adverfary to permit
him to begin the game or not.
i 4- the adverfary plays or difcovers a check to a
player’s king, and give no notice of it, the player may
let him Hand ftill till he does.
5. After the king is moved, a player cannot caftle.
^ Sarafin has an exprefs treatife on the different opi¬
nions of the origin of the Latin fchacchi, whence the
French ethecs, and our chefs, is formed. Menage is
alfo very full on the fame head. Leunclavius takes it
to come from Ufcoches, famous Turkish robbers : P.
Sirmond, from the German /cache, “ theft and that
iiom calculus. He takes chefs to be the fame with the
ludus latrunculorum of the Romans, but miftakenly. This
83] CHE
opinion is countenanced by VoSlius and Salmafius, who
derive the word from calculus, as ufed for latrunculus,
. 1 oloianus derives it from the Hebrew,yWA, vala-
v,t, ct mat mortuus ; whence check and checkmate. Fa-
bncius fays, a celebrated Perfian aftronomer, one Scha-
tien.eha, invented the game of chefs ; and gave it his
own name, which it ftill bears in that country. Nicod
derives it iiova fchecque, or xeque, a Moorish word for
lord, king, and prince. Bochart adds that fcach is ori-
gtnally Perfian ; and that fcachmat in that language
fignifies the king is dead.— The opinion of Nicod and
Bochart, which is likewife that of Scriverius, appears
the moft probable.
Mr Twifs mentions a fmall treatife on chefs, written,
as he fuppofes, about 400 years ago ; at the end of
which is a reprefentation of a round cbefs-board, with
direcfions for placing the men upon it. In this the
knight can cover the 64 fquares on the board at as
many moves. The board is divided into thefe 64 parts
by four concentric circles, having an empty fpace in
the middle; and each of thefe is divided into 16 parts.
Number i is placed in the cutermoft circle ; number
2 in the third circle counting inwards, in the division to
the right hand of the former ; number 3 is placed in
the outermoft circle, in the divifion to the right hand
ot 2 ; 4 in the third circle counting inwards to the
right hand of three; and thus alternately from the
firit to the third, and from the third to the firft circle,
till the round is completed by 16 on the third circle to
the left hand of 1. Number 17 is then placed on the'
divifion of the innermoft circle to the right hand of 1 •
18 on the fecond circle counting inwards, to the right
hand of 17; and thus alternately from the fourth to
the Second, and from the fecond to the fourth circles
until the round is completed by 32, direftlv below’
number 1. Number 33 then is placed on the third
circle directly to the right hand of number 2 ; 34 on
the fourth circle, to the right hand of 4 ; and thus al¬
ternately between the third and fourth circles, until
the round is again completed by 48 on the fourth cir¬
cle, direaiy below number 33. The numbers are now
placed in a retrograde fafliion ; 50 on the outer circle
in that divifion immediately to the right hand of 1 •
51 on the third circle, to the left hand of 2 ; and di¬
reaiy below number 32; 52 is then placed on the
outer circle, immediately on the left hand of 1 ; r,
on the third circle direaiy to the left hand of 16 and
thus alternately on the firft and third circles, until the
laft ground is completed by 64 between the number 3
and 5. On this round chefs-board, fuppofing the black
king to be placed in number 48 on the fourth circle, the
queen ftands on number 17 at his left hand; the bi¬
shops in 33 and 2 ; the knights 18 and 47 ; the caftles
m 3 and 50 ; the pawns on 19, 4, 49, 64, and 46 rf
32, 1. I he white king will then Stand in 25, opposite
^ li b!aC;k qUeen ’ tlle white ftueen in 40 oppofite to
the blac.i King, and fo on. In playing on a board of
this Kind, it will be found, that the power of the caftle
is double to that in the common game, and that of the
biShop only one half; the former having 16 SqUares to.
range in, and the laft only four. The king can caftk-
only one way; and it is very difficult to bring the game
to a conclufion. 6
With regard to the origin of tke game at chefs, we
arc much in the dark. Though it came to us from
the-
Cheis.
CHE
r 734 i
CHE
Chefs, the Saracens, it is by no means probable that they
were the original inventors of it. According to iome,
it was invented by the celebrated Grecian hero D10-
medes. Others fay, that two Grecian brothers^Ledo and
Tyrrheno, were the inventors; and that being much
preffed with hunger, they fought to alleviate the pain by
this amufement. r .
■ According to Mr Irwin it is a game ot Ghinele in¬
vention. During his refidence in India, he found that
a tradition of this nature exifted among the Bramins,
with whom he frequently played the game. W hile
he was at Canton in 1793, he gives the following ac¬
count of the information which he acquired relative to
the origin of the game of chefs. “ A young man¬
darin, of the profeflion of arms, having an inqui-
fitive turn, was my frequent vifitor 5 and, what no
’ quellions could have drawn from him, the accidental
fight of an Enghfh chefs-board effedted. He told me,
that the Chinefe had a game of the fame nature ; and,
on his fpecifying a difference in the pieces and board,
I perceived, with joy, that I had difcovered the defi-
deratum of which I had been fo long in fearch. I ne
very next day my mandarin brought me the board and
equipage 5 and I found, that the Bramins were nei¬
ther miftaken touching the board, which has a river
in the middle to divide the contending parties, nor in
the powers of the king, who is intrenched in a fort,
and moves only in that fpace, in every direflion.
But, what I did not before hear, nor do I believe is
known out of this country, there are two pieces, whofe
movements are diftindl from any in the Indian or Eu¬
ropean game. The mandarin, which anfwers to our
bilhop, in his ftation and fidelong courfe, cannot,
through age, crofs the river •, and a rocket-boy, ftill
ufed in the Indian armies, who is llationed between
the lines of each party, a£ls literally with the motion
of the rocket, by vaulting over a man, and taking his
adverfary at the other end of the board. Except that
the king has his two fons to fupport him, inftead of a
queen, the game, in other refpe&s, is like ours ; as
will appear in the plan of the board and pieces I have
the honour to enclofe, together with dire&ions to
place the men and play the game.
“ As the young man who had difcovered this to me
was of a communicative and obliging difpofition, and
was at this time purfuing his ftudies in the college of
Canton, I requefted the favour of him to confult fuch
ancient books as might give fome infight into the pe¬
riod of the introduction of chefs into China •, to con¬
firm, if pofiible, the idea that {truck me of its having
originated here. The acknowledged antiquity of this
empire, the unchangeable (late of her cuftoms and
manners, beyond that of any other nation in the
world •, and more efpecially the fimplicity of the game
itfelf, when compared to its compafs and variety in
other parts, appeared to give a colour to my belief.
That I was not difappointed in the event, I have no
doubt will be allowed, on the perufal of the tranfla-
tion of a manufcript extradl, which my friend Tinqua
brought me, in compliance with my defire ; and
which, accompanied by the Chinefe manulcript, goes
under cover to your lordfliip. As the mandarin fo-
lemnly affured me that he took it from the work quot¬
ed, and the tranllation has been as accurately made as
poffible, I have no hefitation to deliver the papers as
authentic.
“ From thefe premifes I have therefore ventured to
make the following inferences :—That the game of
chefs is probably of Chinefe origin. That the con¬
fined fituation ^and powers of the king, refembling
thofe of a monarch in the earlier parts of the world,
countenance this fuppofition } and that, as it travelled
weftward, and defcended to later times, the fovereign
prerogative extended itfelf, until it became unlimited,
as in our ftate of the game. I hat the agency of the
princes, in lieu of the queen, befpeaks forcibly the na¬
ture of the Chinefe cuftoms, which exclude females
from all powTer or influence whatever j which princes,
in its paffage through Perfia, w’ere changed into a
Angle vizier, or minifter of ftate, wfith the enlarged
portion of delegated authority that exifts there 5 in¬
ftead of whom, the European nations, with their ufual
gallantry, adopted a queen on their board (d). That
the river between the parties is expreffive of the gene¬
ral face of this country, where a battle could hardly
be fought without encountering an interruption of this
kind, which the foldier was here taught to overcome ‘y
but that, on the introduftion of the game into Perfia,
the board changed with the dry nature of the region,
and the conteft was decided on terra firma. And laft-
ly, that in no account of the origin of chefs, that I
have read, has the tale been fo charaaeriftic or con-
fiftent as that which I have the honour to offer to the
Irifti academy. With the Indians, it was defigned by
a Bramin to cure the melancholy of tne daughter o' a
rajah. With the Perfians, my memory does not afiift;
me to trace the fable } though, if it were more to the
purpofe, I think I fhould have retained it. But, with
the Chinefe, it was invented by an experienced foldier,
on the principles of war. Not to difpel love-fick va¬
pours, or inftrua a female in a fcience that could nei¬
ther benefit nor inform her j but to quiet the mur¬
murs of a difcontented foldiery 5 to employ their va¬
cant hours in leffons on the military art, and to che-
rifti the fplrit of conqueft in the bofom of winter quar¬
ters. Its age is traced by them on record near two
centuries before the Chriftian era 5 and among the nu¬
merous claims for this noble invention, that of the
Chinefe, who call it, by way of diftinaion, chong ke,
or the royal game, appears alone to be indilputable.
Tranjlation of an Rxtracl from the Concum, or Chinefe
Annals, refbecling the Invention of the Game of Chefs,
delivered to me by Tinqua, a Soldier Mandarin of the
Province of Fokien.
“ Three hundred and feventy-nine years after the
Clief?.
(d) That on the acquifition of fo ftrong a piece as the vizier, the pao were fuppreffed, this as poffefling pow¬
ers unintelligible, at that time, to other nations ; and three pawns added, in cor.lequence to make up the num¬
ber of men ; and that as difcipline improved, the lines, which are ftraggling on the Chinefe board, might have
been clofed on ours.
1
CHE [ 785 ] CHE
Chefs, time of Confucius, or one thoufand nine hundred and
"—ilxty-five years ago, Hung Cochu, king of Kiangnan,
fent an expedition into the Shenfi country, under the
command of a mandarin, called Hanfing, to conquer
it. After one fuccefsful campaign, the foldiers were
put into winter quarters j where, finding the weather
much colder than wThat they had been accuftomed to,
and being alfo deprived of their wives and families,
the army, in general, became impatient of their fitua-
tion, and clamorous to return home. Hanfing, upon
this, revolved in his mind the bad confequences of
complying with their wifhes. The necelTity of footh-
ing his troops, and reconciling them to their pofition,
appeared urgent, in order to finilh his operations in
the enfuing year. He was a man of genius, as well
as a good foldier 5 and having contemplated fome time
on the fubjeft, he invented the game of chefs, as well
for an amufement to his men in their vacant hours, as
to inflame their military ardour, the game being whol¬
ly founded on the principles of war. The ftratagem
fucceeded to his wiflr. The foldiery were delighted
with the game ; and forgot, in their daily contefts for
victory, the inconveniences of their poft. In the fpring
the general took the field again ; and, in a few months,
added the rich country of Shenfi to the kingdom of
Kiangnan, by the defeat and capture of its king, Chou-
payuen, a famous warrior among the Chinefe. On
this conqueft Hung Cochu aflumed the title of empe¬
ror, and Choupayuen put an end to his own life in de-
fpair.
I'.xplanation of the Poft ion, Powers and Moves of the
Pieces on the Chinefe Chefs-board, or Chong Ke,
{Royal Game).
“ As there are nine pieces inftead of eight, to oc¬
cupy the rear rank, they ftand on the lines between,
and not within, the fquares. The game is confequent-
ly played on the lines.
“ The king, or chong, Hands in the middle line of
this row. His moves refemble thofe of our king, but
are confined to the fortrefs marked out for him.
“ The two princes, or fou, ftand on each fide of
him, and have equal powers and limits.
“ The mandarins, or tchong, anfwer to our biihops,
and have the fame moves, except that they cannot
crofs the water or white fpace in the middle of the
board to annoy the enemy, but ftand on the defen-
five.
“ The knights, or rather horfes, called mad, ftand
and move like ours in every refpe6f.
“ The war-chariots, or tche, refemble our rooks or
caftles.
“ The rocket-boys, or pao, are pieces whofe mo¬
tions and powers were unknown to us. They aft with
the direftion of a rocket, and can take none of their
adverfary’s men that have not a piece or pawn inter¬
vening. To defend your men from this attack it is
neceflary to open the line between, either to take off
the check on the king, or to fave a man from being
oaptured by the p;'6. Their operation is, otherwife,
like that of the rook. Their ftations are marked be¬
tween the pieces and pawns.
“ The five pawns, or ping, make up the number of
the men equal to that of our board. Inftead of taking
Vol. V. Part II.
fideways, like ours, they have the rook’s motion, ex- Chefs,
cept that it is limited to one ftep, and is not retro-
grade. Another important point, in which the ping
differs from ours, is that they continue mfatu quo,
after reaching their adverfary’s head quarters. It will
appear, however, that the Chinefe pieces far exceed
the proportion of ours ; which occafions the whole
force of the conteft to fall on them, and thereby pre¬
cludes the beauty and variety of our game, when re¬
duced to a ftruggle between the pawns, who are ca¬
pable of the higheft promotion, and often change the
fortune of the day. The pofts of the ping are marked
in front
But according to Sir William Jones, this game is of Trcn/ vol.
Hindoo invention. “ If evidence w'ere required to prove v'
this faft (fays he f), we may be fatisfied with the tefti-1 AfiatU
mony of the Perfians, who, though as much inclined as Refearth(U
other nations to appropriate the ingenious inventions of V°L "*
r • -\ •/! mcm. p»
a toreign people, unammoufly agree that the game was
imported from the weft of India in the fixth century of
our era. It feems to have been immemorially known
in Hindofan by the name of Cheturanga, i. e. the four
angd's, or members of any army ; which are thefe, e/e-
phants, horfes, chariots, and foot foldiers ; and in this
fenfe the word is frequently ufed by epic poets in their
defeription of real armies. By a natural corruptions of
the pure Sanfcrit word, it W'as changed by the old Per¬
fians into Chetrang ; but the Arabs, who fcon after
took poffeflion of their country, had neither the initial
nor final letter of that word in their alphabet, and con-
fequently altered it further into Shetranj, which found
its way prefently into the modern Perfan, and at length
into the dialefts of India, where the true derivation of
the name is known only to the learned. Thus has a
very fignificant word in the facred language of the
Brahmins been transformed by fucceffive changes into
axedre%, fcacchi, echtcs, chefs, and, by a whimfical con¬
currence of circumftances, has given birth to the Eng-
liflt word check, and even a name to the exchequer of
Great Britain.”
It is confidently afferted, that Sanfcrit books on chefs
exift in Bengal ; but Sir William had feen none of them
when he wrote the memoir which wre have quoted. He
exhibits, however, a defeription of a very ancient Indian
game of the fame kind, but more complex, and in his
opinion more modern, than the fimple chefs of the Per-
Jians. This game is alfo called Chaturanga, but more
frequently Chaturaji, or the four kings, fince it is played
by four perfons reprefenting as many princes, two allied
armies combating on each fide. The defeription is ta¬
ken from a book called Bhawijhya Purdn ; in which the
form and principal rules of this faftitious warfare are
thus laid down : “ Eight fquares being marked on all
fides, the red army is to be placed on the eaft, the green
to the fouth, the yellow to the weft, and the black to
the north. Let the elephant (fays the author of the
Purdn) ftand on the left of the king ; next to him the
borfe -, then the boat ; and before them all, fouryW-/o/-
diers ; but the boat muft be placed in the angle of the
board.”
“ From this paffage (fays the prefident) it clearly
appears, that an army with its four angds muft be pla¬
ced on each fide of the board, fince an elephant could
not ftand, in any other pofition, on the left hand of each
king) and Rachacant (a Pandit) informed me, that
5 G the
CHE f 786 ] CHE
Chefs, tlie board confided, libe ours, of 64 fquares, half of
—/■—"J them occupied by the forces, and half vacant. He ad¬
ded, that this game is mentioned in the oldeft law books,
and that it was invented by the wife of a king, to amufe
him with an image of war, while his metropolis was be •
deged in the fecond age of the world. A flnp or boat
is abfurdly fubdituted, wre fee, in this complex game, for
the rat'h, or armed chariot, which the Bengalefe pro¬
nounce rot'h, and which the Perfians changed into rokh;
whence came the rook of fome European nations j as
the vierge and fal of the French are fuppofed to be cor¬
ruptions of fcr% and jil, the prime minijier aad elephant
of the Perfians and Arabs.”
As fortune is fuppofed to have a great diare in de-
• ciding the fate of a battle, the ufe of dice is introduced
into this game to regulate its moves ; for (fays the Pu-
ran) “ if cinque be thrown, the king or a pawn mud be
moved j if quatre, the elephant} if trois, the horfe ; and
if deux, the boat. The king pades freely on all fides,
but over one fquare only 5 and with the fame limitation
the pawn moves, but he advances draight forward, and
kills his enemy through an angle. The elephant marches
in all direflions as far as his driver pleafes; the horfe
runs obliquely, traverfing the fquares ; and the fnip
/ goes over two fquares diagonally.” The elephant, we
find, has the powers of our queen, as we are plealed to
call the general or minijier of the Perfians > and the Jhip
has the motion of the piece to which we give the unac¬
countable appellation of bijhop, but with a redribtion
which mud greatly leffen its value.
In the Puran are next exhibited a few general rules
and fuperficial direflions for the conduft of the game.
Thus, “ the pawns and the Jhip both kill and may be
voluntarily killed ; while the king, the elephant, and the
horfe, may flay the foe, but mud not expofe themfelves
to be Oain. Let each player preferve his own forces
with extreme care, fecuring his king above all, and not
lacrificing a fuperior to keep an inferior piece.” Here
(fays the prefident) the commentator on the Puran ob-
lerves, that the hoife, who has the choice of eight moves
-rom any central pofition, mud be preferred to the Jhip,
which has omy the choice of four. But the argument
w-ould not hold in common game, where the bijhop
and tower command a whole line, and where a knight is
always of lefs value than a tower in aftion, or the bi-
diop oi that fide on which the attack is begun. “ It
is by the overbearing power of the elephant (continues
the Puran) that the king fights boldly ; let the whole
army therefore, be abandoned in order to lecure the
elephant. 7 he king mud never place one elephant be¬
fore another, unlefs he be compelled by want of room
lor he would thus commit a dangerous fault; and if he
can day one of two hodile elephants, he mud dedroy
that on his left hand.” 1
'Y^t remains of the paflage which w^as copied for
bir William Jones relates to the feveral modes in which
a partial fuccefs or complete vidory may be obtained
by any one of the four players ; for, as in a difpute be¬
tween two allies, one of the kings may fometimes af-
iume the command of all the forces, and aim at a fepa
rate conqued. Fird, “ When any one king has placed
himielf on the fquare of another king (which advantage
is called fnhpfana or the throne) he wins a dake, which
is doubled if he kill the adverl'e monarch when hefeizes
his place 5 and if he can feat himfelf on the throne of
his ally, he takes the command of the whole army.” Chefs.
Secondly, “ If he can occupy iuccedively the thrones 1 v—*
of all the three piinces, he obtains the viftory, which is
named cheturaji; and the dake is doubled if he kill the
lad of the three, jud before he takes pofl'efiion of his
throne ; but if he kill him on his throne, the dake is
quadrupled.^ Both in giving the fnhafana and the che¬
turaji the king mud be fupported by the elephants, or
by all the forces united.” Thirdly, “ When one player
has his own king on the. board, but the king of "his
partner has been taken, he may replace his captive ally,
it he can leize botti the adverle kings or if he cannot
effedl their capture, he may exchange his king for one
of them, againd the general rule, and thus redeem the
allied prince, who will fupply his place.” This advan¬
tage has the name of nripacrifeta or recovered by the
king. Fourthly, “ If a pawn can march to any fquare
on the oppofite extremity of the board, except that
of the king, or that of the drip, he affumes whatever
power belonged to that fquare.” Here We find the
rule, with a flight exception, concerning the advance¬
ment oi pawns, which often occafions a mod intered-
ing druggie at our common chefs ; but it appears that,
in the opinion of one ancient writer on the Indian
game, this privilege is not allowable when a player has
three pawns on the board 5 but when only one pawn
and one diip remains, the pawn may advance even to
the fquare of a king or a diip, and affume the pow-er of
either. Fifthly, According to the people of Lance,
where the game was invented, “ there could be neither
vibfory nor defeat if a king were left on the plain with¬
out force ; a fituation which they named cacacajht'‘ha.','>
Sixthly, “ If three diips happen to meet, and the fourth
diip can be brought up to them in the remaining angle,
this has the name of vrihannauca ; and the player of
the fourth feizes all the others.”
The account of this game in the original Sanfcrit is
in verfe.
This game was very fadiionable in former times in
every part of Europe ; though in this country it is
not now very common, probably on account of the
intenfe application of thought required to play at it.
It has long been a favourite of the Icelanders and
other northern people. 7'hcre is little difference be¬
tween their game and ours.
The game of chefs has been generally praflifed by
the greated warriors and generals 5 and fome have even
fuppofed that it was necedary for a military man to be
well {killed in this game. It is a game which has
fometbing in it peculiarly intereding. We read
that Tamerlane was a great chefs-player, and was en¬
gaged in a game during the very time of the decidve
battle with Bajazet the Turkidi emperor, who was de¬
feated and taken prifoner. It is alio related of A1 A-
min the caliph of Bagdad, that he was engaged at chefs
with his freedman Kuthar at the time when A1 Ma-
mun’s forces were carrying on the fiege of that city
with fo much vigour that it was on the point of being
carried by aflault. Dr Hyde quotes an Arabic hidory
of the Saracens, in which the caliph is faid to have
cried out when warned of his danger, Let me alone,
for I fee checkmate againd Kuthar! We are told that
Charles I. was at chefs when news were brought of the
final intention of the Scots to fell him to the Englidij
but fo little was he difeompofed by this alarming in¬
telligence,
CHE [ 7^7 1 CHE
Chefs, telligence, that he continued his game with the utmoft
compofure ; fo that no perfon could have known that
the letter he received had given him information of
any thing remarkable. King John was playing at
chefs when the deputies from Rouen came to acquaint
him that their city was belieged by Philip Augullus ;
but he would not hear them until he had finifhed his
game.
The following remarkable anecdote we have from
Dr Robertfon in his Hiftory of Charles V. John Fre¬
deric, elector of Saxony, having been taken prifoner by
Charles, was condemned to death. The decree was in¬
timated to him while at chefs with Ernelt of Brunf-
wic, his fellow-prifoner. After a Ihoit paufe, and ma¬
king fome refleftion on the irregularity and injuftice
of the emperor’s proceedings, he turned to his antago-
nift, whom he challenged to finilh the game. He play¬
ed with his ufual ingenuity and attention ; and having
beat Erneft, exprefled all the fatisfa&ion that is com¬
monly felt on gaining fuch victories. He was not,
however, put to death, but fet at liberty after five years
confinement^
In the Chronicle of the Moorifh kings of Granada we
find it related, that in 1396, Mehemed Baiba feized
upon the crown in prejudice of his elder brother, and
pafled his life in one continual round of difafters. His
wars with Caftile were invariably unfuccefsful j and his
death was occafioned by a poifoned veft. Finding his
Cafe defperate, he defpatched an officer to the fort of
Salabreno to put his brother Juzaf to death, left that
prince’s adherents ffiould form any obftacle to his fon’s
fucceffion. The alcayde found the prince playing at
chefs with an alfaqui or prieft. Juzaf begged hard for
two hours refpite, which was denied him ; at laft with
great reluttance the officer permitted him to finiffi the
game j but before it was finilhed a meffenger arrived
with the newrs of the death of Mehemed, and the una¬
nimous eleftion of Juzaf to the crown.
We have a curious anecdote of Ferrand count of
Flanders ; who having been accuftomed to amufe him-
felf at chefs with his wife, and being conftantly beaten
by her, a mutual hatred took place •, which came to
fuch a height, that wffien the count was taken pri¬
foner at the battle of Bavines, ffie fuffered him to re¬
main a long time in prifon, though file could eafily
have procured his releafe.
The game of chefs has undergone confiderable vari¬
ations fince it was firft invented. We have it on good
authority, that among the eaftein nations, the piece
now called the queen wras formerly called the vi'&ir or
king’s minifter, and that the powers of the queen her-
felf were but very fmall. The chefs-boards ufed by
Tamerlane wrere larger, and contained many more
fquares than thofe at prefent in ufe. Carrera invented
two new pieces to be added to the eight commonly in
ufe. One of thefe, which he calls Campions, is placed
between the king’s knight and caftle ; the other, named
• Centaur, between the queen’s knight and caftle, has
the move of the bifhop and knight united. This in¬
vention, however, did not furvive its author. In an¬
other of this kind, the two additional pieces are called
the centurion and decurion ; the former, fituated between
the king and his biftiop, in its move the fame with
that of the queen, but only for two fquares j the latter
moves as the bifliop, but only one fquare at a time.
I his, like the former, died with its inventor. The Chefs
chefs-board of Tamerlane was a parallelogram, having !!
II fquares one way and 12 the other. In the Me- . rhefter-
moirs of the late Marffial Keith, we find it related,
that he invented an amulement fomething fimilar to
that of chefs, with wffiich the king of Pruffia was high¬
ly entertained. Several thoufand fmall ftatues were
caft by a founder ■, and thefe were ranged oppofite to
each other as if they had been drawn up in an army ;
making the different movements with them as in real
fervice in the field.
A very complicated kind of game at chefs wras
invented by the late duke of Rutland. At this the
board has 14 fquares in breadth, and 10 in height,
which make in all 140 houfes : and there are 14 pawns
on each fide, which may move either one, two, or three
fquares the firft time. The other pieces were the king,
queen, two bifhops, two knights, a crowned caftle
uniting the ftiove of the king and caftle, and a com¬
mon caftle. On the other fide of the king was a con*
cubitie, whofe move united that of the caftle and knierht,
two biftiops, a fingle knight, a crowned caftle, and a
common one. In this game the pawns are of very
little ufe $ and by the extent of the board, the knights
lofe much of their value, which confequently renders
the game more defeftive and lefs interefting than the
common one.
There is an amufing variety at the game of chefs,
in wffiich the king w'ith eight pawns engages the whole
fet, by being allow'ed to make two moves for every
one of his adverfary. In this he is almoft certain of
coming off vidlorious; as he can make his firft move
into check, and the fecond out of it. Thus he can
take the queen when ffie ftands immediately before her
king, and then retreat j for he cannot remain in
check. He cannot be check-mated unlefs his adver¬
fary has preferved his queen and both caftles.
CnESS-trees, (toquets d'anjure) ; two pieces of wrood
bolted perpendicularly, one on the ftarboard, and ano¬
ther on the larboard fide of the ffiip. They are ufed
to confine the clue, or lower corners of the main-fail;
for which purpofe there is a hole in the upper part,
through which the rope paffes that ufually extends the
clue of the fail to windward. See Tack.
The chefs-trees are commonly placed as far before
the main maft as the length of the main beam.
CHEST, in commerce, a kind of meafure, contain¬
ing an uncertain quantity of feveral commodities.
A cheft of fugar, v. g. contains from to to 1 y
hundred weight; a cheft of glafs, from two hundred
to three hundred feet ; of Caftile foap, from tw-o and
a half to three hundred weight •, of indigo, from one
and a half to two hundred weight, five (core to the
hundred.
Chest, or ‘Thorax. See Anatomy Index.
CHESTER, commonly caMzd VVeJl-Chefer, to di-
ftinguifh it from many other Chefters in the kingdom j
the capital of Chefhire in England. It is a very an¬
cient city, fuppofed to have been founded by the Ro¬
mans j and plainly appears to have been a Roman fta-
tion by the many antiquities which have been and are
ftill difeovered in and about the town. It v’as among
the laft places the Romans quitted •, and here the Bri¬
tons maintained their liberty long after the Saxons had
got poffeffion of the reft of their country. At prefent
5 G 2 it
Chefler,
Chefter
le-Street.
G K E [ 7
it is a large well-built, wealthy city, and carries on a
confiderable trade. Mr Pennant calls it a city without
tparallel, on account of the lingular ftrudlure of the
four principal ftreets. They are as if excavated out
of the earth, and funk many feet beneath the furface ;
the carriages drive far beneath the level of the kitchens
on a line with ranges of {hops. The houfes are moftly
of wood, with galleries, piazzas, and covered walls
before them •, by which not only the fhops, but thofe
who are walking about the town, are fo hid, that one
would imagine there were fcarce any inhabitants in it,
though it is very populous. But though by this con¬
trivance fuch as walk the ftreets are fcreened from
rain, &c. yet the (hops are thereby rendered dark and
inconvenient. The back courts of all the houfes are
on a level with the ground ; but to go into any of the
four principal ibreets, it is necelfary to defcend a flight
of feveral fteps.
Chefter is a bifhop’s fee. It v/as anciently part
of the diocefe of Litchfield ; one of whofe bifliops
removing the feat of his fee hither in the year 1075,
occafioned his fucceflbrs to be frequently ftyled biffoops
of Che/ler. But it was not ere&ed into a dilfin£l
bifliopric until the general diffolution of monafteries,
when King Henry VIII. in the year 1541, raifed
it to this dignity, and allotted the church of the
abbey of St Werburg for the cathedral, ftyling it
the cathedral church of Chrifl and the bleffed Virgin ;
adding the bilhopric to the province of Canterbury :
but foon after he disjoined it from Canterbury, and
added it to the province of York. When this ab¬
bey was diflblved, its revenues w’ere valued at 1003I.
5s. ltd. This diocefe contains the entire counties
ofChefter and Lancafter, part of the counties of Weft-
morland, Cumberland, and Yorkfliire, two chapel-
ries in Denbighihire, and five parilhes in Flintlhire ;
amounting in all to 256 pariflies, of which tot are
impropriations. This bilbopric is valued in the king’s
nooks at 420I. is. 8d. and is computed to be worth
annually 2700I. ; the clergy’s tenth amounting to
435^ 12s. Io this cathedral belong a dean, two
archdeacons, a chancellor, a treafurer, fix prebendaries,
and other inferior officers and fervants. W. Long.'
3. o. N. Lat. 53. 12.
Chester le-Street, the Cuncacefre of the Saxons ; a
,;mall thoroughfare town between Newcaftle and Dur¬
ham, with a good church and fine fpire. In the
Yixon times this place was greatly refpefted on ac¬
count of the relicks of St Cuthbert, depofited here by
Biihop Eardulf, for fear of the Danes, who at that
time (about 884) ravaged the country. His (brine
became afterwards an objeft of great devotion. King
Athenian, on his expedition to Scotland, paid it a
vifit, to obtain, by interceflion of the faint, fuccefs on
ms arms ; beftowed a multitude of gifts on the church ;
and directed, m cafe he died in his enterprife, that his
-Jody fhould be interred there. At the fame time that
this place was. honoured with the remains of St Cuth¬
bert, the bifhopnc of Lindesfarn was removed here,
and endowed with all the lands between the Tyne and
n6! aVcrV!£ Pr,erent COUnty of Durham- was
ifyled St Cuthbert s patrimony. The inhabitants had
great privileges, and always thought themfelves exempt
from all military duty, except that of defending the
body of their faint. Chefter-le-Street may be con-
83 ] C H E
fidered as the parent of the fee of Durham : for when
the relicks were removed there, the fee in 995 followed
them. Tanner fays, that probably a chapter of monks,
or rather fecular canons, attended the body at this
place from its firft arrival: but Bifliop Beke, in 1286,
in honour of the faint, made the church collegiate,
and eftablifhed here a dean and fuitable ecclefiaflics ;
and among other privileges, gave the dean a right of
fdhing on the Were, and the tythe of fi(h.
Ncw-Chester, a town of Pennfylvania in America,
and capital of a county of that name. It is feated on
the Delawar 5 and has a fine capacious harbour, ad¬
mitting veffels of any burden. W. Long. 74. 7. M,
Lat. 40. 15.
CHEST ERFIELD, a market-town of Derbyfliire
in England, pleafantly fituated on a hill between two
fmall rivers. It has the title of an earldom •, and a
confiderable market for corn, lead, and other country
commodities. The houfes are for the mod part built
of rough Hone, and covered with Hate. W. Long. 1.25.
N. Lat. 53. 20.
Chesterfield, Earl of. See Stanhope.
CHEVAL de Frise, a large piece of timber pier¬
ced, and traverfed with wooden pikes, armed or
pointed with iron, five or fix feet long. See Plate
CXXXVII.
Cheft-r
, II
Chtvre at.
The term is French, and properly fignifies a Frief-
land horfe; as having been firft invented in that coun¬
try.—It is alfo called a Turnpike or Turniquet.
Its ufe is to defend a paflfage, flop a breach, or make
an entrenchment to flop the cavalry. It is fometimes
alfo mounted on wheels, with artificial fires, to roll
down in an affault. Errand obferves, that the prince
of Orange ufed to inclofe his camp with Chevaux de
Frife, placing them one over another.
CHEVALER, in the manege, is faid of a horfe,
when in paffaging upon a walk or trot, his oflf fore¬
leg croffes or overlaps the near fore-leg every fecond
motion.
CHEVALIER, a French term, ordinarily fignify-
ing a Knight. The word is formed of the French,
cheval “ horfe,” and the barbarous Latin cavallus.
It is ufed, in heraldry, to fignify any cavalier or
horfeman armed at all points; by the Romans called
cataphraBus eques : now out of ufe, and only to be feen
in coat-armour.
CHEVAUX de Frise. See Cheval de Frife.
CHEVIN, a name ufed in fome parts of England
for the Chub.
CHEVIOT, or (Tiviot) hills, run from north to
fouth through Northumberland and Cumberland j and
were formerly the borders or boundaries between Eng¬
land and Scotland, where many a bloody battle has:
been fought between the two nations 5 one of which is
recorded in the ballad of Chevy-chafe. Thefe hills
are the firfl: land difeovered by failors in coming from,
the eaft into Scotland.
CHEVISANCE, in Law, denotes an agreement or
compofition, as an end or order fet down between a
creditor and his debtor, &c. In the ftatutes, this
word is moll commonly ufed for an unlawful bargain
or contra6f.
CHEVREAU, Urban, a learned writer, born at
Lundun in 1613. He diftinguifiied himfelf in his youth
by his knowledge of the belles lettres j and became fe-
cretary
CHE
[ 789 ]
C H I
Cbeyne.
Chevron cretary of ftate to Queen Chriftina of Sweden. Seve¬
ral German princes invited him to their courts •, and
Charles Lewis, the elector palatine, retained him un¬
der the title of counfellor. After the death of that
prince, he returned to France, and became preceptor
to the duke of Maine. At length retiring to Lundun,
he died there in 1701, aged 88. He was the author
of feveral books ; and amongft others of an Univerfal
Hiftory, which has been often reprinted,
CHEVRON, or Cheveron, in Heraldry. See
H ERALDRY.
CHEWING-balls, a kind of balls made of afafoe-
tida, liver of antimony, bay wood, juniper-wood, and
pellitory of Spain ; which being dried in the fun, and
wrapped in a linen cloth, are tied to the bit of the
bridle for the horfe to chew ; they create an appetite j
and it is faid, that balls of Venice-treacle may be ufed
in the fame manner with good fuccefs.
CHEYKS. See Bengal, N° 17.
CHEYNE, Dr George, a phyfician of great learn¬
ing and abilities, born in Scotland in 1671, and edu¬
cated at Edinburgh under the great Dr Pitcairn. He
pa{fed his youth in clofe lludy, and with great tem¬
perance j but coming to fettle at London, when about
30,- and finding the younger gentry and free-livers to
be the moft eafy of accefs and mod: fufceptible of
friendihip, he changed on a hidden his former manner
of living, in order to force a trade, having obferved
this method to fucceed with fome others. The con-
fequence was, that he grew daily in bulk, and in in¬
timacy with his gay acquaintance *, fwelling to fuch an
enormous fize, that he exceeded 32 done weight; and
he was forced to have the whole fide of his chariot
made open to receive him into it ; he grew diort-
breathed, lethargic, nervous, and fcorbutic ; fo that
his life became an intolerable burden. In this deplo¬
rable condition, after having tried all the powTer of
medicine in vain, he refolved to try a milk and vege¬
table diet ; the good effedds of which quickly appear¬
ed. Plis fize was reduced almod a third ; and he re¬
covered his drengtb, activity, and cheerfulnefs, with
the perfecd ufe of all his faculties. In drort, by a re¬
gular adherence to this regimen, he lived to a mature
period, dying at Bath in 1742, aged 72. He wrote fe¬
veral treatifes that wTere well received ; particularly,
“ An Effay on Health and Long Life and “ The
Engiifh Malady, or a Treatife of Nervous Difeafes
both the refult of his own experience. In fhort, he
had great reputation in his own time, both as a prac¬
titioner and as a writer; and mod of his pieces paffed
through feveral editions. He is to be ranked among
thofe phyficians w-ho have accounted for the operations
of medicines and the morbid alterations udiich take
place in the human body, upon mechanical piinciples.
A fpirit of piety and of benevolence, and'an ardent zeal
for the interefts of virtue, are predominant throughout
his writings. An amiable candour and uigenuoufnefs
are alfo difcernible ; and wLich led him to retraft wdth
readinefs whatever appeared to him to be cenfurable in
what he had formerly advanced. Some of the meta.
phylical notions which he has introduced into his
books may perhaps juftly be thought fanciful and ill-
grounded ; but there is an agreeable vivacity in his
produflions, together wdth much opennefs and frank-
nefsy and in general great perfpicuity.
Chicane.
CHIABRERA, Gabriel, efteemed the Pindar of Chlabiera
Italy, was born at Savona in 1552, and went to ftudy
at Rome. The Italian princes, and Urban VIII. gave
him public marks of their efteem. He wrote a great
number of poems ; but his lyric verfes are inoft admi¬
red. Fie died at Savona in 1638, aged 86.
CHIAN earth, in Pharmacy, one of the medici¬
nal earths of the ancients, the name of which is pre-
ferved in the catalogues of the materia medica, but of
which nothing more than the name has been known
for many ages in the (hops.
It is a very denfe and compafl earth ; and is fent
hither in fmall fiat pieces from the ifland of Chios, in
which it is found in great plenty at this time. It
(lands recommended to us as an aftringent. They tell
us, it is the greatell of all cofmetics ; and that it gives
a wdiitenefs and fmoothnefs to the (kin, and prevents
wrinkles, beyond any of the other fubftances that have
been celebrated for the fame purpofes.
CHIAOUS, a word in the original Turkifh figni-
fying “ envoys,” are officers to the number of five or
fix hundred in the grand fignior’s court, under the
command of a chiaous bafchi. They frequently meet
in the grand vifir’s palace, that they may be in readi¬
nefs to execute his orders, and carry his difpatches in¬
to all the provinces of the empire. The chiaous baf¬
chi a flirts at the divan, and introduces thofe who have
bufinefs there.
CHIAPA, the capital of a province of the fame
name in Mexico, fituated about 300 miles eaft of A-
capulco. W. Long. 98. o. N. Lat. 16. 30.
Chi/ipa el Real, a to>' n of Mexico, in a province of
the fame name, with a birtiop’s fee. Its principal-
trade confifts in chocolate-nuts, cotton, and fugar,
W. Long. 98. 35. N. Lat. 16. 20.
Chiapas de los Indos, a large and rich town of
North America, in Mexico, and in a province of
the fame name. The governor and moft of the in¬
habitants are originally Americans. W. Long. 98. 5.
N. Lat. 15. 6.
CHIARI, JosesH, a celebrated Italian painter, was
the difciple of Carlo Maratti; and adorned the churches
and palaces of Rome with a great number of fine paint¬
ings. Fie died of an apoplexy in 1727, aged 73.
Chiari, a town of Italy, in the province of Brefcia,
and territory of Venice, 7 miles weft of Brefcia, and
27 eaft of Milan. Here the Imperialifts gained n vic¬
tory over the French in 1701; E. Long. 18. 18.
N. Lat. 45. 30.
CHIARO scuro. See CiAPO-Obfcuro.
CHIAVENNA, a handfome, populous, and large
town of Swiflerland, in the country of the Grifons.
It is a trading place, .efpecially in wine and delicate
fruits. The governor’s palace and the churches are
very magnificent, and the inhabitants are Roman Ca¬
tholics. It rvas at one period during the late conteft
with France, the fcene of much carnage and bloodftied.
It is feated near the lake Como. E. Long. 9. 29.
N. Lat. .46. 15.
CHIAUSI, among the Turks, officers employed
in executing the vizirs, bafhaws, and other great men :
the orders for doing this, the grand fignior fends them
wrapped up in a black cloth; on the reception of
which they immediately perform their office.
CHICANE, or Chicanery, in Law, an abufe of
judiciary
Chicane
C H I
judiciary proceeding, tending to delay the caufe, to
Chicuitos. Puzz,e ^ judge, or impofe upon the parties.
Chicane, in the fchools, is applied to vain fo-
phifras, diftinaions, and fubtleties, which protrad dif-
putes, and obfcure the truth.
CHICHEST ER, the capital city of the county of
SufTex, was built by CiiTa, the fecond king of the
South Saxons, and by him called Ciffan CceJJer. It is
fuirounded with a wall, which has four gates anfwer-
ing to the four cardinal points ; from which run two
llreets, that crofs one another In the middle and form
a fquare, where the market is kept, and where there
is a fine ftone piazza built by Bilhop Read. The fpace
between the weft and fouth gates is taken up with the
cathedral church and the bifhop’s palace. It has five
parifh-churches j and is feated on the little river La-
yant, which wafhes it on all fides except the north.
I his city would have been in a much more flourifhing
condition if it had been built by the fea-fide ; how!
ever, the inhabitants have endeavoured to fupply this
defeft in lome meafure, by cutting a canal from the
city down to the bay. The principal manufattures
ot the town are malt and needles. The market ofChi-
c lefter is noted for fifh, wheat, barley, malt, and oats ;
the fineft lobfters in England are bred in the Lavant •
and it is obfervable, that this river, unlike moft others’
is very low in winter, but in fummer often overflows
its banks. Chichefter is a city and county of itfelf •
it is governed by a mayor, recorder, aldermen, com!
mon-council without limitation, and four iuftices of
the peace chofen out of the aldermen ; and it fends
two members to parliament. It is a biftiop’s fee.
I he cathedral church was anciently dedicated to St
1 eter. It was new built by Radulph, the twenty-fifth
bifliop ; but being deftroyed by fire, it was again
xult by Seffridus II. the twenty-ninth bifliop. This
ee hath yielded to the church two faints, and to the
r "£tlon ,!hree loJd chancellors, two almonets, and one
chancelfor to the univerfity of Oxford. Anciently
the bdhops °f Cluchefter were con.feffors to the queens
co^llfe J hlr d'OCe.fe COntains the whole the
the , yhVnSuffeXr ^excePtlng 22 pariflies, peculiars of
t e archbilhop °f Canterbury), wherein are 2co pa-
nflies, whereof ,I2 are impiopriated. It hafh turn
archdeacons, viz. of Chichefter and Lewes ; is valued
mthe kings books at 667k is. 3d. and is computed
to be worth annually 2600!. The tenths of the
whole clergy is 287I. 2s. 0^. To the cathedral be¬
long a bifliop, a dean, two archdeacons, a treafurer
a chancellor thirty-two prebendaries, a chanter, twelve
Lat 5oh°o ’ 3nd °ther °fficers' W- Long. 50. N.
youn^oCfKtL°r n-HICKEN’ Jn denotes the
young of the gallinaceous order of birds, efpeciallv
the common hen. See Phasi o-tiq On ! ec!aJ1y
/nJeX' x-hasianus, Ornithology
CHICK-Weed. See Alsine, Botany Index
CHICKUNr S" MEt,'c'NE. «*•
See EorS"?;A?ame g'V'n “ ^ Ut"-
nU,eS con lift of honey and .,.axa ^
a itants are very voluptuous, yet very warlike^ 7'bpv
maintained bloody wars with the Spaniards till ,650;
[ 79° ]
C H I
fince r hich, fome of them have become Chriftians. It
is bounded by la Plata on the north eaft, and by Chili
on toe weft.
CHiDLEY, or Chimley, a market-town of De-
vonlhire, fituated in W. Long. 4. o. N. Lat. 51. o.
CHIEF, a term fignifying the head cr principal
part of a thing or perfon. Thus we fay, the chief of
a party, the chief of a family, &c. The word is form¬
ed of the French chef “ head of the Greek
caput, “ head 5” though Menage derives it from the
Italian capo, formed of the Latin, caput.
Chief, in Hera/dry, is that ivhich takes up all the
upper part of the efcutcheon from fide to fide, and re-
prefents a man’s head. In chief imports fomething
borne in the chief part or top of the efcutcheon.
CHIEFTAIN, denotes the captain or chief of any
clafs, family, or body of men. Thus the chieftains
or chiefs of the Highland clans, were the piincipal
noblemen or gentlemen of their refpe&ive clans. See
Clans.
. CHIELEFA, a ftrong town of Turkey in Europe,
in the Morea. It was taken by the Venetians in iC8c *
but after that the Turks retook it, with all the Mo!
rea. E. Long. 22. 21. N. Lat. 26. 50.
CHIGI, Fabio, or Pope Alexander VII. was
born at Sienna in 1599. His family finding him a
hopeful youth, lent him early to Rome, where he foon
engaged in a friendfhip with the marquis Pallavicini,
who recommended him fo effe&ually to Pope Urban
VIII. that he procured him the poft of inquifitor at
Malta. He was fent vice-legate to Ferrara, and af¬
terward nuncio into Germany : there he had an op¬
portunity of difplaying his intriguing genius 5 for he
was mediator at Munfter, in the long conference held
to conclude a peace with Spain. Cardinal Mazarin
had fome refentrnent againft Chigi, who was foon af¬
ter made a cardinal and fecretary of ftate by Inno¬
cent X. but his refentment was facrificed to political
views. In 1655, when a pope w'as to be chofen, Car¬
dinal Sacchetti, Mazarin’s great friend, finding it w^as
impofiible for him to be raifed into St Peter’s chair,
becaufe of the powerful oppofition made by the Spa-
nifh faflion, defired Cardinal Mazarin to confent to
Cliigi s exartation. His requeft wras granted, and he
was elefled pope by the votes of all the 64 cardinals
who were in the conclave : an unanimity of which
there are but few inftances in the ekaion of popes.
He fhowed uncommon humility at his ekaion, and at
fnft forbade all his relations to come to Rome wflth-
out his leave ; but he foon became more favourable to
his nephew's, and loaded them with favours. It is af-
ferted that he had once a mind to turn Proteftant.
I he newfpapers in Holland beftowed great encomi¬
ums upon him ; and acquainted the world that he
oid not approve of the cruel perfecutions of the Wal¬
den fes in Piedmont. There is a volume of his poems
extant. He loved the Belles-Lettres, and the conver-
fation of learned men. He was extremely fond of
ft.ttely buildings : the grand plan of the college Della
Sapietrza, which he finiftied, and adorned with a fine
library, remains a proof of his tafte in archite61ure.
He died in 1667.
CHILBLAIN [pernio), in Medicine, a tumor af-
fe&ing the feet and hands; accompanied with an in¬
flammation, pains, and fometimes an ulcer or folution
of
Chicfley
. . II .
Chilblain,
Quid
Children.
CHI [ 79
of continuity : in which cafe it takes the denomina¬
tion of chops on the hands, and of hibes on the heels.
Chilblain is compounded of chill and blain ; q. d. a
blain or fore contra&ed by cold. Pernio is the Latin
name adopted by phyficians; and is derived by Vof-
iius from perna, “ a gammon of bacon,” on account
of feme refemblance. Chap alludes to gape, both in
found and appearance. Kibes, in Welch kibws, may
be derived from the German kerben, “ to cut 3” the
fkin, when broke, appearing like a cut.
Chilblains are occalioned by exceflive cold flopping
the motion of the blood in the capillary arteries. See
the article Pernio.
CHILD, a term of relation to parent. See Parent
and Children.
_ Bartholine, Pare, Licetus, and many other writers,
give an account of a petrified child, which has feemed
wholly incredible to fome people. The child, how-
ever, which they deferibe, is Hill in being 5 and is
kept as a great rarity in the king of Denmark’s mu-
feum at Copenhagen. The woman who wras big with
this, lived at Sens in Champagne in the year 1582 3 it
was cut out of her belly, and was univerfally fuppofed
to have lain there about 20 years. That it is a real
human foetus, and not artificial, is evident to the eyes
r>f any obferver 3 and the upper part of it, when exa¬
mined, is found to be of a fubflance refembling the
gypfum or Hone whereof they made the plafter of Pa¬
ris : the lower part is much harder, the thighs and
buttocks being a perfeft Hone of a reddilh colour, and
as hard as common quarry Hone : the grain and fur-
face of this part appears exactly like that of the cal¬
culi or Hones taken out of human bladders : and the
whole fubHance, examined ever lb nearly, and felt ever
fo carefully, appears to be abfolute Hone. It was car¬
ried from Sens to Paris, and there purchafed by a
goldfmith of Venice 3 and Frederic III. king of Den¬
mark purchafed it of this man at Venice for a very large
fum, and added it to his colleftion of rarities.
CniLD-Bed. 1 c nr
_ Chud Birth, j See Midwifery.
CaiLD-Wit, a power to take a fine of a bond-wo¬
man unlawfully gotten with child, that is, without
confent of her lord. Every reputed father of a bale
child got within the manor of Writtel in Efiex, pays
to. the lord a fine of 3s. 4d.; where, it feems, child-
wit extends to free as well as bond women.
CHILDERMAS-day, or Innocents Day, an an-
niverfary held by the church of England on the 28th
of December, in commemoration of the children of
Bethlehem mafiacred by order of Herod.
CHILDREN, the plural of Child.
Mr Derbam computes, that marriages, one with an¬
other, produce four children not only in England but
in other parts alfo.
In the. genealogical hiftory of Tufcany, written by
Gamafini, mention is made of a nobleman of Sienna,
named Pichi, who of three w ives had 150 children i
and that, being fent ambaffador to the pope and the
emperor, he had 48 of his fons in his retinue. In a
monument in the church-yard of St Innocent, at Pa-
ereffed to a woman who died at 88 years of age 3
it. is recorded, that fhe might have feen 288 children
direbtly iiTued from her. This exceeds what Hake-
well relates of Mrs Honeywood, a gentlew’oman of
1 1 CHI
Kent, born in the year 1527, and married at 16 to Children,
her only hufband R. Honeywood of Charing, Eiq. 11 ''
and died in her 93d year. She had 16 children of her
own body 3 of which three died young, and a fourth
had no iffue : yet her grandchildren, in the fecond ge¬
neration, amounted to 1143 in the third, to 2283
though in the fourth they fell to 9. The whole num¬
ber ihe might have feen in her life-time, being 367.
^ + 228-j-9=367. So that Hie could fay the
lame as the diitich does of one Dalburg’s family
at Bazil:
a,/ ■ 2 • 3 • 4
Mater ait nata, die natce jiha natam,
5 6
lit moneat, natce plangere, Jiliolam.
Management of Children. See Infant.
Overlaying of Children, is a misfortune that fre¬
quently happens 3 to prevent which, the Florentines
have contrived an inftrument called arcuccio. See Aa-
cuccio.
Children are, in Law, a man’s Hue begotten on
his wife. As to illegitimate children, fee Bastard.
For the. legal duties of parents to their children,
fee the articles Parent and Bastard.
As to the duties of children to their parents, they
arile from a principle of natural juftice and retribu¬
tion. For to thofe who gave us exiltence, we natu¬
rally owe fubjedtion and obedience during our mino¬
rity, and honour and reverence ever after ; they who
protedfed the weaknefs of our infancy, are entitled to
our protedfion in the infirmity of their age 3 they wdro
by fuflenance and education have enabled their oft-
fpring to profper, ought, in return, to be fupported
by that offspring, in cafe they Hand in need of afliH-
ance. Upon this principle proceed all the duties of
children to their parents, which are enjoined by poli-
tive law7s. And the Athenian laws carried this prin¬
ciple into pradtice with a fcrupulous kind of nicety,
obliging all children to provide for their father when
fallen into poverty ; with an exception to fpurious
children, to thofe whofe chaflity had been proHituted
with confent of their father, and to thofe whom he
had not put in any way of gaining a livelihood. The
legiilature,. fays Baron Montefquieu, confidered, that,
in the firff cale, the father, being uncertain, had ren¬
dered the natural obligation precarious 3 that, in the
fecond cafe, he had fulhed the life he had given, and
oone his children the greateH of injuries, in depriving
them of their reputation 3 and that, in the third cafe,,
he had rendered their life (fo far as in him lay) an in-
fupportable burden, by furnifliing them with no means
of fubfiflence.
Our law7s agree with thofe of Athens, with regard
to the. firft only of thefe particulars, the cafe of fpu¬
rious Hue. In the other cafes, the law7 does not hold
the tie of nature to be dHolved by any mifbehavi-
our.of the parent; and, therefore, a child is equal-
ly juffifiable in defending the perfon, or maintain¬
ing the caufe or fuit, of a bad parent as of a good
one 3 and is equally compellable, if of fufficient abili¬
ty, to maintain and provide for a wicked and unnatu¬
ral progenitor, as for one wdio has Hiown the greateH;
tendernefs and parental piety. See further the article
Filial AfeClion.
CHILI,
C H I [
Chili.1 CHILI, a province of South America, bounded by
^ " ',"1 Peru on the north, by the province of La Plata on the
eaft, by Patagonia on the fouth, and by the Pacific
ocean on the wed, lying between 75 and 85 degrees
of weft longitude j and between 25 and 45 of
fouth latitude ; though fome comprehend in this pro¬
vince Patagonia and Terra del Fuego.
The firft attempt of the Spaniards upon this coun¬
try was made by Almagro in the year I535> after he
and Pizarro had completed the conqvieft of Peru. He
fet out on his expedition to Chili with a confiderable
body of Spaniards and auxiliary Indians. For 200
leagues he was well accommodated with every ne-
ceffary by the Indians, who had been fubjedls of the
emperors of Peru : but reaching the barren country
of Charcas, his troops became difcontented through
the hardihips they fuffered ; Which determined Alma¬
gro to climb the mountains called Cordilleras ; in order
to get the fooner into Chili; being ignorant of the in¬
valuable mines of Potofi, contained in the province of
Charcas, where he then was. At that time the Cor¬
dilleras were covered with fnow, the depth of which
obliged him to dig his way through it. The cold
made fuch an impreflion on his naked Indians, that it
is computed no lefs than 10,000 of them perilhed on
thefe dreadful mountains, 150 of the Spaniards (haring
the fame fate ; while many of the furvivors loll their
fingers and toes through the excels of cold. At half,
after encountering incredible difficulties, Almagro
reached a fine, temperate, and fertile plain on the op-
pofite fide of the Cordilleras, where he was received
with the greateft kindnefs by the natives. Thefe poor
favages, taking the Spaniards for deputies of their god
Virachoca, immediately colleifled for them an offering
of gold and filver worth 290,000 ducats: and foon
after brought a prefent to Almagro worth 300,000
more. Thefe offerings only determined him to con¬
quer the wTole country as foon as pofhble. The In¬
dians among w-hom he now was had acknowledged the
authority of the Peruvian incas, or emperors, and
confequently gave Almagro no trouble. He therefore
marched immediately againtl thofe who had never
been conquered by the Peruvians, and inhabited the
fouthern parts of Chili. Thefe favages fought with
great refolution, and difputed every inch of ground ;
but in five months time the Spaniards had made fuch
progrefs, that they muff infallibly have reduced the
whole province in a very little time, had not Almagro
returned to Peru, in confequence of a commiffion fent
him from Spain.
In 1540, Pizarro having overcome and put Alma¬
gro to death, fent into Chili, Baldivia or Valdivia,
who had learned the rudiments of war in Italy, and
was reckoned one of the beft officers in the Spanith
fervice. As he penetrated foutlnvards, however, he
met with much oppofition ; the confederated caziques
frequently gave him battle, and difplayed-great cou¬
rage and refolution j but could not prevent him from
penetrating to the valley of Mafiocho, which he found
incredibly fertile and populous. Flere he founded the
city of St Jago ; and finding gold mines in the neigh¬
bourhood, forced the Indians to work in them : at the
tame time building a caftle for the fafety and protec¬
tion of his new colony. The natives, exafperated at
.this flavery, immediately took up arms j attacked the
2
)2 ] CHI
fort 5 and though defeated and repulfed, fet fire to
the outworks, which contained ail the provifions of
the Spaniards. Nor were they difcouraged by this and
many other defeats, but (till continued to carry on the
w’ar with vigour. At lart, Valdivia, having overcome
them in many battles, forced the inhabitants of the
vale to fubmit 5 upon which he immediately fet them
to work in the mines of Quilotta. This indignity of¬
fered to their countrymen redoubled the fury of thofe
who remained at libery, Their utmoft efforts, how¬
ever, were as yet unable to flop Valdivia’s progrefs.
Having croffed the large rivers Maulle and Hata, he
traverfed a vaft tradl of country, and founded the city
of La Conception on the South-fea-coaft. He eredled
fortreffes in feveral parts of the country, in order to
keep the natives in awe ; and built the city called Im¬
perial, about 40 leagues to the fouthward of Concep¬
tion. The Spanifh writers fay, that the neighbouring
valley contained 80.coo inhabitants of a peaceable dif-
pofition 4 and who w!ere even fo tame as to (uffer Val¬
divia to parcel out their lands among his followers,
while they themfelves remained in a (late of inadlivity.
About v6 leagues to the eaftward of Imperial, the Spa-
niih general laid the-foundations of the city Villa Rica,
fo called on account of the rich gold mines he found
there. But his ambition and avarice had now involved
him in difficulties from which he could never be ex¬
tricated : He had extended his conquefts beyond what
his ftrength w'as capable of maintaining. The Chile-
fians -were (till as defirous as ever of recovering their
liberties. The horfes, fire-arms, and armour of the
Spaniards, indeed, appeared dreadful to them; but
thoughts of endlefs (lavery wrere ftill more fo. In the
courfe of the wrar they had difcovered that the Spa¬
niards were vulnerable and mortal men like themfelves j
they hoped, therefore, by dint of their iuperiority in
numbers, to be able to expel the tyrannical ufurpers.
Had all the nations joined in this refolution, the Spa¬
niards had certainly been exterminated j but fome of
them were of a pacific and fearful difpofition, while
others confidered fervitude as the greateft of all pot-
fible calamities. "Of this laft opinion -were the Arac-
1 ceans, the moft intrepid people in Chili, and who had
given Valdivia the greateft trouble. They all role to
a man, and chofe Capaulican, a renowned hero among
them, for their leader. Valdivia, however, received
notice of their revolt fooner than they intended he
(hould, and returned with all expedition to the vale of
Araccea j but before he arrived, 14,000 of the Chi-
lefians w7ere there affembled under the conduft of Ca¬
paulican. He attacked them with his cavalry, and
forced them to retreat into the woods •, but could not
obtain a complete -victory, as they kept continually
(allying out and haraffing his men. At laft Capauli¬
can, having obferved that fighting with fuch a num¬
ber of undhciplined troops only ferved to contribute to
the defeat and confufion of the whole, divided his for¬
ces into bodies of 1000 each. Thefe he dire&ed to
attack the enemy by turns 5 and, though he did not
expeft that a (ingle thoufand would put them to flight,
he diredled them to make as long a (land as they could j
when they w7ere to be relieved and fupported by ano¬
ther body j and thus the Spaniards would be at laft
W'earied out and overcome. The event fully anfwered
his expectations. The Chilefians -maintained a fight
CHI [ 793 ]
CK;i;. for feven or eight hours, until the Spaniards, grow- fifted by art
ing faint for want of refrefhment, retired precipitately.
Valdivia ordered them to poflfefs a pafs at fome diftance
from the field, to flop the purfuit j but this defign be¬
ing difcovered to the Chilefians by the treachery of
his page, who was a native of that country, the Spa¬
niards were furrounded on all fides, and cut in pieces
by the Indians. The general was taken and put to
death ; fome fay with the tortures ufually infli&ed by
thofe favages on their prifoners ; others, that he had
melted gold poured down his throat j but all agree,
that the Indians made flutes and other inflruments of
his bones, and preferved his fkull as a monument of
their victory, which they celebrated by an annual fef-
tival. After this victory the Chilefians had another
engagement with their enemies $ in which alfo they
proved vidtorious, defeating the Spaniards with the
lofs of near 3000 men j and upon this they bent their
whole force againft the colonies. The city of Con¬
ception, being abandoned by the Spaniards, was taken
and deftroyed : but the Indians were forced to raife
the fiege of Imperial j and their progrefs was at laft
flopped by Garcia de Mendoza, who defeated Capau-
lican, took him prifoner, and put him to death. No
defeats, however, could difpirit the Chilefians. They
continued the war for 50 years and to this day they
remain unconquered, and give the Spaniards more
trouble than any other American nation. Their mod
irreconcilable enemies are the inhabitants of Araccea
and Tucapel, thofe to the fouth of the river Bobia,
or whofe country extends towards the Cordilleras.—
The manners of thefe people greatly refemble thofe of
North America, which we have already defcribed under
the article America ; but they feem to have a more
warlike difpofition. It is a conftant rule with the Chi¬
lefians never to fue for peace. The Spaniards are ob¬
liged not only to make the firfl: overtures, but to pur-
chafe it by prefents- They have at laft been obliged
to abandon all thoughts of extending their conquefts,
and reduced to cover their frontiers by erefting forts
at proper diftances.
The Spanifh colonies in Chili are difperfed on the
borders of the South-fea. They are parted from Peru
by a dtfert of 80 leagues in breadth ; and bounded by
the ifland of Chiloe, at the extremity next the ftraits
of Magellan. There are no fettlements on the coaft,
except thofe of Baldivia, Conception iiland, Valparaifo,
and Coquimbo or La Serena, which are all fea-ports.
In the inland country is St Jago, the capital of the co¬
lony. There is no culture nor habitation at any di¬
ftance from thefe towns. The buildings in the whole
province are low, made of unburnt brick, and moftly
thatched. This praftice is obferved on account of
the frequent earthquakes $ and is properly adapted to
the nature of the climate, as well as the indolence of
the inhabitants.
The climate of Chili is one of the moft wholefome
in the whole world. The vicinity of the Cordilleras
gives it fuch a delightful temperature as could not
otherwife be expedled in that latitude. Though gold
mines are found in it, their richnefs has been too much
extolled; their produce never exceeds 218,750!.
The foil is prodigioufly fertile. All the European
fruits have improved in that happy climate. The
wine would be excellent if nature were properly af-
Vol. V. Part II. . x
CHI
and the corn-harveft is reckoned a bad
one when it does not yield a hundred fold. With all
thefe advantages, Chili has no direft intercourfe with
the mother-country. Their trade is confined to Peru, v
Paraguay, and the favages on their frontiers. With
thefe laft they exchange their lefs valuable commodi¬
ties, for oxen, horfes, and their own children, whom
they are ready to part with for the moft trifling things.
This province fupplies Peru with great plenty of hides,
dried fruit, copper, falt-meat, horfes, hemp, lard,
wheat, and gold. In exchange it receives tobacco,
fugar, cocoa, earthen-ware, w’oollen cloth, linen, hats,
made at Quito, and every article of luxury brought
from Europe. The Ihips fent from Callao on this
traffic were formerly bound to Conception Bay, but
now come to Valparaifo. The commerce between this
province and Paraguay is carried on by land, though
it is a journey of 300 leagues, 40 of which lie through
the fnows and precipices of the Cordilleras ; but if it was
carried on by fea, they muft either pafs the ftraits of
Magellan or double Cape Horn, which the Spaniards
always avoid as much as poffible. To Paraguay are
fent lome -woollen fluffs called ponchos, wffiich are ufed
for cloaks ; alfo wines, brandy, oil, and chiefly gold.
In return they receive wax, a kind of tallow fit to
make foap, European goods, and negroes.
Chili is governed by a chief, who is abfolute in all
civil, political, and military affairs, and is alfo inde¬
pendent of the viceroy. The latter has no authority
except when a governor dies ; in which cafe he may
appoint one in his room for a time, till the mother-
country names a fucceffor. If, on fome occafions, the
viceroy has interfered in the government of Chili, it
was when he has been either authorized by a particu¬
lar truft repofed in him by the court, or by the defe¬
rence paid to the eminence of his office ; or when he
has been adluated by his own ambition to extend his
authority. In the whole province of Chili there are
not 20,000 white men, and not more than 60,000 ne¬
groes, or Indians, able to bear arms. The military
eftabliftiment amounted formerly to 2000 men ; but
the maintaining of them being found too expenfive, they
were reduced to 500 at the beginning of this century.
CHILIAD, an affemblage of feveral things ranged
by thoufands. The word is formed of the Greek
fciXtois, mille, “ a thoufand.”
CHI LI AGON, in Geometry, a regular plain figure
of 100 fides and angles. Though the imagination
cannot form the idea of fuch a figure, yet w'e may
have a very clear notion of it in the mind, and can
eafily demonftrate that the fum of all its angles is
equal to 1996 right ones : for the internal angles of
every plane figure are equal to twice as many right
ones as the figure hath fides, except thofe four which
are about the centre of the figure, from whence it
may be refolved into as many triangles as it has fides.
The author of VArt de Venfer, p. 44. has brought this
inftance to (how the diftinftion between imagination
and conceiving.
CEIILIARCHA, or Chiliarchus, an officer in the
the armies of the ancients, who had the command of a
thoufand men.
CHILIASTS in church-hiftory. See Millena-
RIANS.
CHILLINGWORTH, William, an eminent di-
5 H vine
Chile
.11
Chilling-
worth.
G H I
Chilling-
worth
vine of the church of England, was born at
(| 1602, and bred there. He made early great pro-
Chiloe. ficiency in his ftudies, being of a very quick genius.
—V—' He vvas an expert mathematician, as well as an able
divine, and a very good poet. Study and converfa-
tion at the univerfity turning upon the controverfy
between the church of England and that of Rome, on
account of the king’s marriage with Henrietta daugh¬
ter to Henry IV. king of France, Mr Chillingworth
forfook the church of England, and embraced the
Romifh religion. Dr Laud, then biihop of London,
hearing of this, and being greatly concerned at it,
wrote Mr Chillingworth ; who expreffing a great deal
of candour and impartiality, that prelate continued to
correfpond with him. This fet Mr Chillingworth on
a new inquiry 5 and at laft determined him to return
to his former rchgion. In 1634 he wrote a confuta¬
tion of tne arguments which had induced him to go
over to the church of Rome. He fpoke freely to his
iriends of all the difficulties that occurred to him ;
which, gave occafion to a groundlefs report, that he
had turned Papift a fecond time, and then Proteftant
again. His return to the communion of the church
of England made a great noife, and engaged him in
leveral drfputes with thofe of the Romiih perfuafion.
Rut in 1635 he engaged in a work which gave him a
inr greater opportunity to confute the principles of the
church of Rome, and to vindicate the Proteftant re-
hg.on, under the title of “ The Religion of Prote-
ftants a fafe Way to Salvation.” Sir Thomas Coven¬
try, lord keeper of the great feal, offering him pre¬
ferment Mr Chillmgworth refufed to accept it on ac¬
count of his fcruples with regard to the fubfcription of
the 39 articles. However, he at laft furmounted thefe
cuifues; and being promoted to the chancellorftiip
of the church of Sarum, with the prebend of Brix-
worth m Northampton (hire annexed to it, he com
,the uiua! fubfcriptiorr. Mr Chillingworth
was .ealoully attached to the royal party ; and in
Auguft ^ was prefent in King Charles L>s amly
re Red Jff G1°UCefte.r’ where ^ advifed and di
town 9 maTg Cftam enSines for affaulting the
town. Soon after, having accompanied the Lord
Hopton general of the king’s forces in the weft to
Arundel caftle m Suffex, he was there taken prifoner
Wiir P wan enta7 forCeS under the command of Sir
V ham Waller, who obliged the caftle to furrender
Rut his nlnefs increafing, he obtained leave to he
conveyed to Chichefter, where he was lodged at the
bfthop’s palace and after a ftmrt ficknel d d in
J644. He hath left feveral excellent workJ behind
SeC PersepolIS.
PillLU, one of the feven fa<Tes of Greece c
«o % that th were
oJLe'i* "juk •:riu«beft to ^
According to Pliny, it wa^ he who ","rmLur,ng-”
featence, to be writtcn 'f1’’0"
'Craple of Uelphos. It is faid t|,at he
fon, who had been
[ 794 1 CHI'
Oxford in South America, under the 43d degree of fouth la¬
titude. It is the chief of an archipelago of 40 iflands
and its principal town is Caftro. It rains here almoft
all the year, infomuch that nothing but Indian com
or fome fuch grain, that requires but little heat to ril
pen it, can ever come to perfeRion. They have ex¬
cellent fhell-fifti, very good wild-fowl, hogs, Iheep, and
beeves j as aifo a great deal of honey and wax. They
carry on a trade with Peru and Chili ; whither they
fend boards of cedar, of which they have vaft forefts.
CHILTENHAM, a town in Gloucefterfhire, fix
miles from Gloucefter ; noted for its purgative chaly¬
beate fpring, which has rendered it of late years a place
of falhionable refort. This water, which operates with
great cafe, is deemed excellent in fcorbutic complaints
and has been ufed with fuccefs in the gravel.
CHILTERN, a chain of chalky hills forming the
lout hern part of Buckingbamfhire, the northern part
of the county being diftinguifhed by the name of th-
r ^ °n tbefe heights is extremely health¬
ful : 1 he foil, though ftony, produces good crops of
wheat and barley ; and in many places it is covered
with thick woods, among which are great quantities
°t beech —Cfa/tern is alfo applied to the hilly parts
of Eerkftnre, and it is believed has the fame meaning
!" ^mre Gther counties. Hence the Hundreds lyin?
m thole parts are called the CM/ern Hundreds.
. Ch'*-**™ Hundreds, Stewards of. Of the hundreds
into which many of the Englilh counties were divided by
Emg Alfred for the better government, the iurifdiRiou
was originally vefted in peculiar courts ; but came after¬
wards to be devolved to the county courts, and fo re¬
mains at prefent ; excepting with regard to fome, as the
which have been by privilege annexed to the
Cif°?n* H-de having ftill their own courts, a Jleward
ot thole courts is appointed by the chancellor of the
exchequer, with a falary of 20s. and all fees, &c. be¬
longing to the office : And this is deemed an appoint-
35 t0 Vacate 3 feat in Parliament.
CHIMERA, a port town of Turkey in Europe,
-ua ed^at the entrance of the gulf of Venice, in the
r ° ~kP,rus» about 32 miles north of the city
whhd A-a ^h‘-h "r16 the mountains of Chimera,
N Lat 40 .of’'"8 frM"TBca'a'y- E- Long. 20. 40.
c HIM/ERA’ in fabulous hiftory, a celebrated mon-
prung from Echidna and Typbon. It had three
tinuaiw a 'n"’ * ^ and ? drag°u i and con-
were hyofe°omf,te The fore Pa^S °f its ^ody
and th, h- I" °n’ tbe middle W39 that of 3
and thei hinder parts were thofe of a dragon. It ge-
fter
head;
with joy, while embracir.p- his
Cr<cmdr rUbe 0I^mpic ga'mes-
"IL0E; an iUand 17lng near the coaft 0f Chili
tain in I veil ieCi‘°r tbat toeie was a burning moun-
account oH ’7. f ^i"35 ‘lhe refort ^ oi>
was fruitf’d l del°late u;ildernefs ; the middle which
tom the marffiv3: ^ g°atS ’ 3”d at ths bot-
lerophon is laid foT^ ab°unded Wlth ferPents. Bel-
caufe he delayed thedudY'fl ,CMEa!ra’ be-
and rendered it h- k\ li Jcads on that mountain,
coptain oltl f f “Th ,a>'stha'
the images of'a lio, "h0 “1<n'm;d thei'' <Wp with
Bv T A ’ 3 Z°Zt’ and a dragon.
7 a among the philofo|hers. Is under-
- Rood
Chiltenhaai
...I'
Chnnffira,
Chimes
tyVefas ^y/C /(?C' tsma
^Cy^.2. JETate CXLIV.
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CHI
Crimes, flood a mere creature of the imagination, compofed
v—of fuch contradiftions and abfurdities as cannot pof-
flbly anywhere exifl but in thought.
CHIMES of a Clock, a kind of periodical mufic,
produced at equal intervals of time, by means of a
particular apparatus added to a clock.
In order to calculate numbers for the chimes, and
adapt the chime-barrel, it muft be obferved, that the
barrel muft turn round in the fame time that the tune
it is to play requires in finging. As for the chime-
barrel, it may be made up of certain bars that run
athwart it, with a convenient number of holes punch¬
ed in them to put in the pins that are to draw each
hammer : and thefe pins, in order to play the time
of the tune rightly, muft ftand upright, or hang down
from the bar, fome more, fome lefs. To place the
pins rightly, you may proceed by the way of changes
on bells, viz. I, 2, 3, 4 j or rather make ufe of the
muflcal notes. Obferve what is the compafs of your
tune, and divide the barrel accordingly from end to
end.
Thus, in the examples on Plate CXLIV. each of
the tunes is eight notes in compafs $ and accordingly
the barrel is divided into eight parts. Thefe divifions
are ftruck round the barrel j oppofite to which are the
hammer-tails.
We fpeak here as if there were only one hammer
to each bell, that it may be more clearly apprehend¬
ed •, but when two notes of the fame found come to¬
gether in a tune, there muft be two hammers to the
bell to ftrike it : fo that if in all the tunes you intend
to chime of eight notes compafs, there ftiould happen
to be fuch double notes on every bell, inftead of eight
you muft have fixteen hammers ; and accordingly you
muft divide the barrel, and ftrike fixteen ftrokes round
it, oppofite to each hammer tail j then you are to di¬
vide it round about into as many divifions as there are
mufical bars, femibreves, minims, &c. in the tune.
Thus the hundredth-pfalm tune has 20 femibreves,
and each divifion of it is a femibreve : the firft note
of it alfo is a femibreve j and, therefore, on the chime-
barrel muft; be a whole divifion, from five to five ; as
you may underftand plainly, if you conceive the fur-
face of a chime-barrel to be reprefented by the above
figures, as if the cylindrical fuperficies of the barrel
tyere ftretched out at length, or extended on a plane:
and then fuch a table, fo divided, if it were to be
' wrapped round the barrel, would ftiow the places where
all the pins are to ftand in the barrel j for the dots
running about the table are the places of the pins that
play the tune.
Indeed, if the chimes are to be complete, you ought
to have a fet of bells to the gamut notes ; fo as that
each bel! having the true found of /<?/, /#, mi, fa, you
may play any tune with its flats and (harps; nay, you
may by this means play both the bafs and treble with
one barrel : and by fetting the names of your bells at
the head of any tune, that tune may eafily be tranf-
ferred to the chime-barrel, without any fidl! in mufic':
but it muft be obferved, that each line in the mufic is
C H I
three notes diftant; that is, there is a note between Chimney,
each line, as well as upon it. «—
CHIMNEY, in ArchiteElure, a particular part of a
houfe, where the fire is made, having a tube or funnel
to carry off the fmoke. The word chimney comes
from the French cheminee; and that from the Latin
caminata, “ a chamber wherein is a chimney camina-
ta, again, comes from caminus; and that from the
Greek xx/aivo?, “ a chimney $” of xxia, uro, “ I burn.1’
Chimneys are ufually fuppofed a modern invention j
the ancients only making ufe of ftoves : but Oftavio
Ferrari endeavours to prove chimneys in ufe among
the ancients. To this end, he cites the authority of
Virgil,
Et jam fumma procul mllarum citlmina fumant:
and that of Appian, who fays, “ That of thofe per-
fons profcribed by the triumvirate, fome hid them-
felves in wells and common fewers, and fome on
the tops of houfes and chimneysfor fo he under-
ftands KXTrtuaiis V7>u^a'^nx%,fumariafuh te&opofta. Add,
that Ariftophanes, in one of his comedies, introduces
his old man, Polycleon, (hut up in a chamber, whence
he endeavours to make his efcape by the chimney,
Chimnies, in Profeffor Beckman’s opinion, are com-
paratively of modern invention. We (hall lay before
our readers fome obfervations from his elaborate difier-
tation on this fubjedt. He thus explains the above
paifage of Virgil.
“ When the triumviri, fays Appian*, caufed thofe * 2), £,.//;#
who had been profcribed by them to be fought for by tivilib. lib.
the military, fome of them, to avoid the bloody hands’y-P- 962*
of their perfecutors, hid themfelves in wells, and others, ^°^1*
as Ferrarius tranfiates the words, in fumaria fuh tetto,
qua fcilicetfumus e tecio evohitur (a). The true tranf-
lation, however, (fays Mr Beckmann) is fumofa ccena-
cuta. The principal perfons of Rome endeavoured to
conceal themfelves in the fmoky apartments of the up¬
per ftory under the roof, which, in general, were in¬
habited only by poor people ; and this feems to be con¬
firmed by what Juvenal f exprefsly fays, Rarus venit f Sat. x.
in ccenacula miles. ver- 27*
“ Thofe paflages of the ancients which fpeak of
fmoke rifing up from houfes, have with equal impro¬
priety been fuppofed to allude to chimneys, as if the
fmoke could not make its way through doors and win¬
dows. Seneca J writes, ‘ Laft evening I had fome t Epijl. 64.
friends with me, and on that account a ftronger fmoke
was raifed ; not fuch a fmoke, however, as burfts forth
from the kitchens of the great, and which alarms the
watchmen, but fuch a one as fignifies that guefts are
arrived.’ Thofe whofe judgments are not already warp¬
ed by prejudice, will undoubtedly find the true fenfe
of thefe words to be, that the fmoke forced its way
through the kitchen windows. Had the houfes been
built with chimney-funnels, one cannot conceive why
the watchmen ftiould have been alarmed when they ob¬
ferved a ftronger fmoke than ufual arifing from them 5
but as the kitchens had no convenience of that nature,
an apprehenfion of fire, when extraordinary entertain-
5 H 2 ments
[ 195 3
W      - - -■     —      
.(a) E$ KXTnuiiu', r, rm nym txis Mgxfiw fivaj.itvxig.
(
r
C H I
Chimney, ments were to be provided in tbe houfes of the rich for
'—■-'v-™ large companies, feems to have been well founded j
and on fuch occafions people appointed for that pur-
pofe were flationed in the neighbourhood to be con-
flantly on the watch, and to be ready to extinguilh
the flames in cafe a fire fhould happen. There are
many other paffages to be found in Roman authors of
the like kind, which it is hardly neceffary to mention j
* Edog'1' fuch as that of Virgil*,
ver. S3. 6 ’
Et jam fumma procul villarum culmlna fumant.
f Aulular. and following wmrds of Plautus f, defcriptive of a
*a.n.fc.4. mifer:
§>uin divum atque hominum clamat continuo fidcm,
Suam rem periiffe, feque eradicarier,
De fuo tigillo fumus jl qua exit foras.
“ The paffage of Ariflophanes above alluded to,
however, (fays the profeffor) which, according to the
ufual tranflation, feems to allude to a common chimney,
can, in my opinion, efpecially when we confider the
illuftration of the fcholiafts, be explained alfo by a Am¬
ple hole in the roof, as Reifke has determined ; and
indeed this appears to be more probable, as we find
mention made of a top or covering with which
the hole was clofed.”
It has been faid that the inftances of chimneys remain¬
ing among the ruins of ancient buildings are few, and
that the rules given by Vitruvius for building them are
obfcure j but it appears that there exilt vo remains of an¬
cient chimneys ; and that Vitruvius gives no rules,
either obfcure or perfpicuous, for building what, in the
modern acceptation of the word, deferves the name of
a chimney.
“ The ancient mafon-wmrk ftill to be found in Italy
does not determine the queftion. Of the walls of towns,
temples, amphitheatres, baths, aqueducts, and bridges,
there are fome though very imperfect remains, in which
chimneys cannot be expe£ted ; but of common dwell¬
ing houfes none are to be feen, except at Herculaneum,
and there no traces of chimneys have been difcovered.
The paintings and pieces of fculpture which are prefer-
ved, afford us as little information ; for nothing can be
perceived in them that bears the fmalleft refemblance to
a modern chimney.
_ “ If there were no funnels in the houfes of the an¬
cients to carry off the fmoke, the direftions given by
Columella, to make kitchens fo high that the roof fhould
not catch fire, was of the utmoft importance. An
accident of the kind, which that author feems to have
apprehended, had almoft happened at Beneventum,
xvhen the landlord who entertained Maecenas and his
company was making a ftrong fire in order to get fome
birds fooner roafted.
■ ubi fedulus hofpes
Peine arfit, macros dum tuvdos vetj'at in igne
Nam vagaper veterem dilapfo jiamma culinam
«I Herat. Vulcano fummum properabat lumbere tedium t
lib, i. fat. 5.
Had there been chimneys in the Roman houfes, Vitru¬
vius certainly would not have failed to deferibe their
conftruction, which is fometimes attended with confider-
able difficulties, and which is intimately connefted with
the regulation of the plan of the whole edifice. He
G H I
does not, however, fay a word on this fubjed; neither Chimney.
does Julius Pollux, who has colledted with great care 1 
the Greek names of every part of a dwelling-houfe j
and Grapaldus, who in later times made a colledtion
of the Latin terms, has not given a Latin word expref-
five of a modern chimney * Frandfd
“ Caminus fignified, as far as I have been able to MariiGra-
learn, firft a chemical or metallurgic furnace, par-
which a crucible was placed for melting and refiningadivm
metals j fecondly, a fmith’s forge; and, thirdly, a ^
hearth on which portable ftoves or fire-pans wrere pla¬
ced for warming the apartment. In all thefe, however,
there appears no trace of a chimney.” Herodotus re¬
lates (lib. viii. c. 137.), that a king of Libya, when
one of his fervants afked for his wmges, offered him
in jefl the fun, which at that time fhone into the houfe
through an opening in the roof, under which the fire
was perhaps made in the middle of the edifice. If fuch
a hole muff be called a chimney, our author admits that
chimneys were in ufe among the ancients, efpecially in
their kitchens ; but it is obvious that fuch chimneys
bore no refemblance to ours, through which the fun
could not dart his rays upon the floor of any apart¬
ment.
“ However imperfect may be the information which
can be colletted from the Greek and Roman authors re-
fpe&ing the manner in which the ancients warmed their
apartments, it neverthelefs flievvs that they commonly
ufed for that purpofe a large fire-pan or portable ftove,
in wffiich they kindled wood, and, when the wood w7as
well lighted, carried it into the room, or which they
filled w'ith burning coals. When Alexander the Great
was entertained by a friend in winter, as the weather
was cold and raw, a fmall fire-bafon was brought into
the apartment to warm it. The prince, obferving the
fize of the veffel, and that it contained only a few coals,
defired his hoft, in a jeering manner, to bring more
wood or frankincenfe ; giving him thus to underhand
that the fire was fitter for burning perfumes than to
produce heat. Anacharfis, the Scythian philofopber,
though difpleafed with many of the Grecian cufloms,
praiied the Greeks, however, becaufe they (hut out the
fmoke and brought only fire into their houfes *. We + PluUrcb.
are informed by Lampridius, that the extravagant He Synpof.
liogabalus caufed' to be burned in thefe (loves, inftead vu 7-
of wood, Indian fpiceries and coftly perfumes f. It
alfo worthy of notice, that coals were found in foreeprid ylta
of the apartments of Herculaneum, as we are told by Heliogab*
Winkelmann, but neither (loves nor chimneys.” cap. 31.
It is well known to every fcholar, that the ufeful arts
of life were invented in the call, and that the cufloms,
manners, and furniture of eaftern nations, have remain¬
ed from time immemorial almoft unchanged. In Per-
fia, w'hich the late Sir William Jones feems to have con-
fidered as the original country of mankind, the me¬
thods employed by the inhabitants for warming them-,
felves have a great refemblance to thofe employed by
the ancient Greeks and Romans for the fame purpofe.
According to De la Valle, the Perfians make fires in
their apartments, not in chimneys as we do, but in
ftoves, in the earth, which they call, tenner. “ Thefe
ftoves confift of a fquare or round hole, two fpans or a
little more in depth, and in drape not unlike an Italian
calk. That this hole may throw out heat fooner, and
with more ftrength, there is placed in it an iron veffel
of
[ 796 1
G H I
Chimney, of the fame fize, which is either filled with burning
v—^ coals, or a fire of wood and other inflammable fub-
ftances is made in it. When this is done, they place
over the hole or ftove a wooden top, like a fmall low
table, and fpread above it a large coverlet quilted with
cotton, which hangs down on all fides to the floor.
This covering condenfes the heat, and caufes it to
warm the whole apartment. The people who eat or
converfe there, and fome who fleep in it, lie down on
the floor above the carpet, and lean, with their (boulders
againfl: the wall, on fquare cufhions, upon which they
fometimes alfo fit 5 for the termor is conftrufted in a
place equally diftant from the walls on both fides.
Tbofe who are not very cold only put their feet under
the table or covering ; but thofe who require more heat
can put their hands under it, or creep under it altoge¬
ther. By thefe means the ftove diffufes over the whole
body, without caufing uneafinefs to the head, fo pene¬
trating and agreeable a warmth, that I never in win¬
ter experienced any thing more pleafant. Thofe, how¬
ever, who require lefs heat let the coverlet hang down
on their fide to the floor, and enjoy without any incon¬
venience from the ftove the moderately heated air of
the apartment. They have a method alfo of ftirring
up or blowdng the fire when necefiaiy, by means of a
fmall pipe united with the tennor or ftove under the
earth, and made to projecft above the floor as high as
one choofes ; fo that the wind, when a perfon blows
into it, becaufe it has no other vent, adls immediately
upon the fire like a pair of bellows. When there is
no longer occafion to ufe this ftove, both boles are
clofed up, that is to fay, the mouth of the ftove and
that of the pipe which conveys the air to it, by a flat
ftone made for that purpofe. Scarcely any appear¬
ance of them is then to be perceived, nor do they oc¬
cafion inconvenience, efpecially in a country where it
is always cuftomary to cover the floor with a carpet,
and where the walls are plaftered. In many parts
thefe ovens are ufed to cook viftuals, by placing ket¬
tles over them. They are employed alfo to bake
bread ; and for this purpofe they are covered with a
large broad metal plate, on which the cake is laid ; but
if the bread is thick and requires more heat, it is put
* WJl. of into the ftove itfelf
Invent. II, The profeflbr farther obferves, the oldeft account
of them which he finds is an infeription at Venice,
wbich relates, that in the year 1347 a great many
chimneys w?ere throwm dowm by an earthquake. It
would appear, however, that in fome places they had
been in ufe for a confiderable time before that period ;
for De Gataris, in his hiftory of Padua, relates, that
Francefco de Carraro, lord of Padua, came to Rome in
1368, and finding no chimneys in the inn wdtere he
lodged, becaufe at that time fire was kindled in a hall
in the middle of the floor, he caufed two chimneys
like thofe which had long been ufed at Padua to be
conftrufted by mafons and carpenters, whom he had
brought along with him. Over thefe chimneys, the
firft ever feen at Rome, he affixed his arms, which
were ftill remaining in the time of De Gataris, who
died of the plague in 1405.
C H I
Method of Building Chimneys that will not ftnohe. Chimney
Workmen have different methods of drawdng up the . ^
funnels of chimneys, generally according to their own Ch^an“
fancies and judgments, and fometimes according to the _■
cuftoms of places. They are feldom direfted by found
and rational principles. It will be found for the moft
part, that the fmoking of chimneys is owing to their
being carried up narrower near the top than below, or
zig zag, all in angles ^ in fome cafes, indeed, it is
owing to accidental caufes; but, for the moft part,
to thofe two above mentioned. Where they are car¬
ried up in the pyramid or tapering form, efpecially if
the houfe be of a confiderable height, it is ten to one
but they fometimes fmoke. The air in the rooms,
being rarefied, is forced into the funnel of the chim¬
ney, and receives from the fire an additional force to
carry up the fmoke. Now it is evident, that the fur¬
ther up the fmokt flies, the lefs is the force that drives
it, the flower it mutt move, and confequently the
more room in proportion it ftiould have to move in 5
whereas in the ufual way it has lefs, by the fides of
the chimney being gathered clofer and clofer to¬
gether.
The method here propofed of carrying up chim¬
neys will be objefted to by fome thus: The wider a
chimney is at the top, fay they, the more liberty has
the wind to blow down. Very true j but is it not re¬
filled in going down, both by the form of the chim¬
ney and other evident caufes, fo that it mull return
again ? In the other way, when the wind blows down,
the refiftance being lefs, the wind and fmoke are, if
we may ufe the expreflion, imprifoned, and make the
fmoke puff out below. This method has proved ef¬
fectual after all others had failed 5 and that in a houfe
placed in the worft fituation poflible, namely, under a
high mountain to the fouthward, from which ftrong
blafts blow down upon it. A vent was carried up
without angles, as perpendicular as poflible j and w^as
made about three or four inches wider at top than at
the bottom : the funnel w-as gathered in a throat di-
reClly above the fire-place, and fo widening upwards.
Since that'time the houfe has not only ceafed to fmoke,
but when the doors Hand open, the draught is fo
ftrong that it will carry a piece of paper out at the
chimney head. See more on this fubjeCl and the im¬
provements by Count Rumford under the article
Smoke.
Chimney-Money, otherwife called Hearth-money, a
duty to the crown on houfes. By flat. 14. Char. II.
cap. 2. every fire-hearth and ftove of every dwelling
or other houfe, within England and Wales (except
fuch as pay not to church and poor), was chargeable
with 2s. per annum, payable at Michaelmas and Lady-
day to the king and his heirs and fucceffors, &c. ;
which payment was commonly called chimney-money.
This tax, being much complained of as burdenfome
to the people, has been fince taken off, and others
impofed in its Head ; among which that on windows
has by fome been efteemed almoft equally grievous.
CHIMPANZEE, in Natural Hi/lory. See Simia.
[ 797 1
END OF THE FIFTH VOLUME,
DIRECTIONS for placing the PLATES of Vol. V.
Part I.
Plate CXXXI. CXXXII. to face
CXXXIII.
CXXXIV;
CXXXV.
CXXXVI.
cxxxvii.
CXXXVIII. cxxxix.
CXL. CXLI.
Part II.
CXLII. CXLIII.
CXL IV.
Page.
14
74
112
260
282
320
318
358
774
79
/
\.