UC-NRLF 
 
 hlfl 575 
 


 
 THE LIBRARY 
 
 OF 
 
 THE UNIVERSITY 
 OF CALIFORNIA 
 
 PRESENTED BY 
 
 PROF. CHARLES A. KOFOID AND 
 MRS. PRUDENCE W. KOFOID 
 
ELEMENTS 
 
 CHEMISTRY, 
 
 WITH 
 
 PRACTICAL, EXERCISES, 
 
 ILLUSTRATED BY 
 
 on 
 
 USE OF SCHOOLS 
 
 BY FRAXCIS J. GRUXD, 
 
 Author of " Elements of Natural Philosophy," " Elements of Plane and 
 
 Solid Geometry," " Popular Lessons in Astronomy," 
 
 ' Exercises in Algebra," " Arithmetic," etc. 
 
 tion and object of Chemistry. 
 
 BOSTON: 
 
 CARTER, HENDEE AND CO, 
 1833. 
 
 (hi 
 
Entered according to act of Congress, in the year 1833, 
 
 BY FRANCIS J. GRUND, 
 in the clerk's office of the District Court of Massachusetts. 
 
75* 
 
 PREFACE. 
 
 IN preparing the following Elementary Treatise of 
 Chemistry, it has been the author's particular study to 
 form a proper scientific arrangement, which shall enable 
 the learner to see the connexions which exist between 
 the different branches of the natural sciences, and to 
 conduct him gradually from a knowledge of the sim- 
 ple bodies, or elements of nature, to a correct under- 
 standing of their more complex combinations. 
 
 The divisions of the work, it is believed, will be found 
 natural, and such as will prove a strong assistance to 
 the memory. 
 
 The Introduction contains the outlines of General 
 Chemistry, treating separately, 
 
 I. Of the definition and object of Chemistry. 
 II. Of Chemical action. 
 
 III. Of the Chemical apparatus, and 
 
 Of the Chemical composition of bodies. 
 
 The first four chapters may be considered as contain- 
 ing the elements of inorganic chemistry. The first treats 
 
iv PREFACE. 
 
 of the gaseous elements and their binary combinations ; 
 the second, of the thirteen non-metallic elements and 
 their binary combinations ; the third chapter treats sep- 
 arately of the metals, and the fourth of the salts. 
 
 To the description of each element is annexed a short 
 table, exhibiting its principal combinations with other 
 substances, and each chapter is followed by questions 
 for recapitulation, which are numbered to correspond 
 with the sections of the book. 
 
 The fifth and sixth chapters treat respectively of 
 vegetable and organic chemistry, and the seventh chap- 
 ter explains the three principal processes of fermentation, 
 or the spontaneous decomposition of organized matter. 
 Each of these chapters is again followed by questions 
 for review, numbered to correspond with the sections 
 of the text. The appendix contains a brief description 
 of the steam engine, with questions for the learner. Nu- 
 merous engravings are introduced for illustrating the ex- 
 periments, and indeed no expense and labor spared to 
 render the work intelligible even to ordinary capacities. 
 
 It is hardly necessary to add that on his tour to 
 Europe the author has had an opportunity to embody 
 in his work the latest discoveries in chemistry, and that 
 it may therefore be reasonable in him to hope that in 
 this respect his book is not inferior to any similar work 
 published in this country. 
 
 BOSTON, OCTOBER 1st, 1833. 
 
TABLE OF CONTENTS. 
 
 INTRODUCTION. 
 
 page. 
 
 I. Definition and Object of Chemistry, . /'_ 
 
 II. Chemical Action, 4 
 
 III. Chemical Apparatus, . . . 
 
 IV. Chemical Composition of Bodies, . . " . . . 36 
 
 RECAPITULATION. 
 
 I. Questions on Definitions, "Mr." . . <( . j. 42 
 
 II. do. on Chemical Action, 43 
 
 III. do. on Chemical Apparatus, .... 46 
 
 IV. do. on the Chemical Composition of Bodies, . 48 
 
 CHAPTER I. 
 
 Of the Properties and Combinations of the Four Gaseous Elements, 
 Oxygen, Hydrogen, Nitrogen, and Chlorine. 
 
 A. Oxygen, tV/--^: *i;n ^. 50 
 
 Theory of Combustion, . . . r. ;,,; . 52 
 
 B. Hydrogen, . . . . . # .j^^ 59 
 
 Properties of Hydrogen gas, 61 
 
 Combination of Hydrogens with Oxygen Water, . 73 
 
 C. Nitrogen or Azote, 87 
 
 Combinations of Nitrogen with Oxygen, ^ -^ u'* " \ 93 
 
 do. Nitrogen with Hydrogen, . . . 101 
 
 D. Chlorine, . . .- 103 
 
 Combinations of Chlorine with Oxygen, ' / '-* 104 
 
 do. do. with Hydrogen, . : .' 106 
 
 do. do. with Nitrogen, .i^i^i^P . 109 
 
 RECAPITULATION. 
 
 Questions for Reviewing some of the most important Principles 
 contained in the 1st Chapter. 
 
 A. Questions on Oxygen, . . v^I'l j*> i^sfiV~:^. 1^ 
 
 B. do. on Hydrogen, . . ' T ; ~ . 112 
 
 # 
 
vi CONTENTS, 
 
 C. Questions on Nitrogen, . . . . . . 116 
 
 D. do. on Chlorine, 120 
 
 CHAPTER II. 
 
 Of the remaining nine Non-metallic Elements, and their 
 combinations, 122 
 
 A. 
 
 Carbon, 
 
 122 
 
 
 Combinations of Carbon with Oxygen, 
 
 . 125 
 
 
 do. do. do. Hydrogen, 
 
 129 
 
 
 do. do. do. Nitrogen, 
 
 . 134 
 
 
 do. of Cyanogen with Oxygen, 
 
 135 
 
 
 do. do. do. Hydrogen, . 
 
 . 135 
 
 
 Other combinations of Cyanogen, 
 
 138 
 
 
 Combinations of Carbon with Chlorine, 
 
 . 138 
 
 
 do. do. do. Sulphur, 
 
 139 
 
 B. 
 
 Sulphur, 
 
 . 141 
 
 
 Combination of Sulphur with Oxygen, 
 
 142 
 
 
 do. do. do. Hydrogen, . 
 
 . 147 
 
 C. 
 
 Silenium, ...... 
 
 149 
 
 D. 
 
 Phosphorus, 
 
 . 149 
 
 
 Combinations of Phosphorus with Oxygen, 
 do. do. do. Hydrogen, 
 
 151 
 . 152 
 
 E. 
 
 Boron, 
 
 155 
 
 
 
 . 155 
 
 F. 
 
 Iodine, . . . . . ".'../' 
 
 '.'*:?. 156 
 
 
 Combination of Iodine with Oxygen, 
 
 157 
 
 
 do. do. do. Hydrogen, 
 
 . 157 
 
 G. 
 
 Bromine, ....... 
 
 158 
 
 
 Combinations of Bromine, .... 
 
 . 159 
 
 H. 
 
 Silicon, ....... 
 
 159 
 
 
 Combinations of Silicon with Oxygen, . 
 
 . 160 
 
 
 Properties of Silex, 
 
 160 
 
 I. 
 
 Fluorine, 
 
 .^ . 162 
 
 
 
 -i'-T V. 162 
 
 
 Other combinations of Fluorine, 
 
 163 
 
 RECAPITULATION. 
 
 Questions for Reviewing the most important Principles contained 
 in Chapter II. 
 
 A. Questions on Carbon, 164 
 
 B. Questions on Sulphur, ...... 167 
 
 C. Questions on Silenium, ...... 169 
 
 D. Questions on Phosphorus, 169 
 
 E. Questions on Boron, 171 
 
 . F. Questions on Iodine, . . 171 
 
 G. Questions on Bromine, 172 
 
 H. Questions on Silicon, . 172 
 
 I. Questions on Fluorine, , . . . . ' 173 
 
. CONTENTS. Vll 
 
 CHAPTER III. 
 OF THE METALS. 
 
 Preliminary remarks, . . . . . . 174 
 
 Jj. Of the six Alkaline Metals, Potassium, Sodium, 
 
 Lithium, Calcium, Barium, and Strontium, . . 180 
 
 1. Potassium, 180 
 
 Combinations of Potassium, 183 
 
 2. Sodium, 185 
 
 Combinations of Sodium, 185 
 
 3. Lithium, 186 
 
 Combinations of Lithium, 187 
 
 4. Calcium, 187 
 
 Combinations of Calcium, 187 
 
 5. Barium, 188 
 
 Combinations of Barium, 188 
 
 6. Strontium, 189 
 
 Combinations of Strontium, ..... 189 
 
 B. Of the six Earthy Metals, Magnesium, Yttrium, JLlumi- 
 um, Glucinum, Zirconium, and Thorium. . . 190 
 
 1. Magnesium 190 
 
 Combinations of Magnesium, 191 
 
 2. Glucinum, 192 
 
 Combinations of Glucinum, ..... 192 
 
 3. Yttrium, 193 
 
 Combinations of Yttrium, ..... 193 
 
 4. Alumium, 193 
 
 Combinations of Alumium, 193 
 
 5. Zirconium 194 
 
 Combinations of Zirconium, 194 
 
 6. Thorium, 195 
 
 Combinations of Thorium, 195 
 
 C. Of the nine Noble Metals, Mercury, Silver, Gold, Plati- 
 num, Palladium, Rhodium, Iridium, Osmium., and Nickel, 195 
 
 1. Mercury, 195 
 
 Combinations of Mercury with Oxygen, . . . 196 
 
 do. do. do. Chlorine, . . 197 
 
 do. do. do. Sulphur, . . . 199 
 
 2. Silver, 200 
 
 Combinations of Silver, 200 
 
 3. Gold, 202 
 
 Combinations 6f Gold, 203 
 
 4. Platinum, . . ,:f ; 204 
 
 5. Palladium, . *'.?:>'.. "/ ; 206 
 
 6. Rhodium, 207 
 
 7. Iridium, , 207 
 
 8. Osmium, . 207 
 
 9. Nickel, . 208 
 
X CONTENTS. 
 
 7. Carbonate of Lead, . . . . . . 283 
 
 8. do. Iron, 284 
 
 9. do. Copper, 284 
 
 G. Phosphates, 234 
 
 1. Phosphate of Ammonia, 285 
 
 2. do. Soda, 285 
 
 3. do. Lime, 286 
 
 H. Chromates, 286 
 
 1. Chromate of Potash, 287 
 
 2. do. Lead, 287 
 
 3. do. Mercury, . 287 
 I. Jlrseniates and JLrsenites, 287 
 
 1. Arsenite of Potash, 288 
 
 2. do. Cobalt, 288 
 
 J5f. Cyanites and Fulminates, 288 
 
 RECAPITULATION. 
 
 Questions for Reviewing the most important Principles contained 
 in Chapter IV. 
 
 I. Questions on the General Remarks on the salts and acids, 289 
 
 Questions on Crystalography, 291 
 
 A. Questions on the Nitrates, 292 
 
 B. Questions on the Chlorates, 293 
 
 C. Questions on the Chlorides, 294 
 
 E. Questions on the Sulphates, 295 
 
 F. Questions on tiie Carbonates, 296 
 
 G. Questions on the Phosphates, 298 
 
 H. Questions on the Chromates, 298 
 
 I. Questions on the A rseniates and A rsenites, . . . 299 
 
 K. Questions on the Fulminates, 299 
 
 CHAPTER V. 
 
 VEGETABLE CHEMISTRY. 
 
 General Remarks on the Difference between Organic and In- 
 organic matter, . . 300 
 
 I. UNSALIFIABLE VEGETABLE SUBSTANCES, . . 303 
 
 A. Neutral Unsaleable Vegetable Substances, , 304 
 
 1. Woody Fibre, ... ; ... 304 
 
 2. Starch, 304 
 
 3. Gum, or Mucilage, 305 
 
 4. Sugar, 305 
 
 B. Watery, Unsaleable Vegetable Substances, . . 306 
 
 1. Volatile or essential oils, 306 
 
 2. Fat or fixed oils, 307 
 
 3. Resins, 308 
 
 4. Wax, . 309 
 
 5. Alcohol, .... '"V . -'. 309 
 
 6. Ether and Naphta, . . . .: . .,* . 310 
 
. CONTENTS. XI 
 
 II. SALIFIABLE VEGETABLE BASES, ... 311 
 
 III. VEGETABLE ACIDS, . 312 
 
 A. Fixed Vegetable Acids, 312 
 
 1. Tartaric acid, 312 
 
 2. Citric acid, ...;... 313 
 
 3. Malic acid, . . . . . . . .313 
 
 4. Oxalic acid, 314 
 
 5. Gallic acid, 314 
 
 6. Vegetable Jelly, or Pectic acid, . . . 314 
 
 7. Bitumous acid, 315 
 
 B. Vegetable Acids capable of Sublimation, , . 315 
 
 1. Benzoic acid, 315 
 
 2. Succinic acid, 316 
 
 3. Boletic acid, . . . . . , . .316 
 
 C. Liquid Vegetable Acids (capable of Distillation), 316 
 1., Acetic acid, 316 
 
 2. Prussia acid, . . .. . . . .318 
 
 3. Cyanic acid, 318 
 
 IV. VEGETABLE SUBSTANCES OF AN UNDETERMINED 
 
 NATURE, '. f . \. 318 
 
 1. Coloring matters, . .' , -. ;v --'.. 318 
 
 2. Vegetable extracts, . :/v r v.r5. :,:<- ;"';. N 
 
 3. Fennentous principles, . . . * ; 320 
 
 a. Lees (dregs), 320 
 
 b. Vegetable albumen, 321 
 
 . c. Gluten, 321 
 
 RECAPITULATION. 
 
 Questions for Reviewing the most important Principles Contained 
 in Chapter V. 
 
 A. Questions on the general remarks on the difference 
 
 between organic and inorganic bodies, v c. , . 322 
 
 Questions on the unsalifiable vegetable substances, . . 323 
 
 Questions on the salifiable vegetable substances, . . 325 
 
 Questions on the vegetable acids, . . . . . 325 
 
 Questions on vegetable substances of aji undetermined nature, 327 
 
 CHAPTER VI. 
 
 ANIMAL CHEMISTRY, . ri** or -: . . . 329 
 
 1. Animal Jelly (Glue), .... *-;,,:.%; 331 
 
 2. Albumen, . 331 
 
 3. Blood, 332 
 
 Chemical changes in the nature of Blood, occasioned 
 
 by Respiration, 333 
 
 4. Of the Milk, 333 
 
 5. Butter, . 334 
 
 6. Cheese, 334 
 
 7. Sugar of milk, . , , ... , . ,. f . 335 
 
XII CONTENTS. 
 
 8. Animal mucus, 335 
 
 9. Animal oils and fats, 335 
 
 10. Animal acids, 336 
 
 a. Olific acid, 336 
 
 6. Lactic acid, 337 
 
 d. Mucous acid, : 
 
 e. Formic acid, . 337 
 
 11. Of the different liquids employed in the process of 
 
 digestion, 338 
 
 a. Saliva, 338 
 
 6. Gastric juice 338 
 
 c. Bile, 338 
 
 12. Of the Chyle, 339 
 
 13. Substance of the Brain and Nerves, . . . .340 
 
 14. Fibrin, 341 
 
 15. Of the Bones, Teeth, and Cartilage, . . . .341 
 
 16. Of the Marrow, 342 
 
 17. Of the Muscles, Membranes, Ligaments and Tendons, . 342 
 
 18. Coverings of animals, 343 
 
 a. Of the skin, . . . . . . . .343 
 
 6. Nails, Claws, Horns, Hoofs, Scales, &c, . . 343 
 
 e. Hair, Bristles, Feathers, Wool, and Silk, . . 344 
 
 RECAPITULATION. 
 
 Questions for Reviewing the most important Principles con- 
 tained in Chapter VI, . . . ,v ... 845 
 
 CHAPTER VII. 
 
 Of the Chemical Process accompanying the Development, Life, 
 and Death of Organized Bodies. 
 
 A. Germination of seeds. . 351 
 
 B. Process of Nutrition necessary to life, . . . 351 
 
 C. Of the spontaneous decomposition of Organic substances, 352 
 
 1. Vinous Fermentation, . 352 
 Phenomena accompanying vinous fermentation, . 353 
 
 2. Acetous Fermentation, 354 
 
 3. Of the process of Putrefaction, .... 355 
 Putrefaction with free access of air, . . . 356 
 Putrefaction with little or no access of air, . . 356 
 
 RECAPITULATION. 
 
 Containing Questions for Reviewing Chapter VII. . . 357 
 
 APPENDIX. 
 
 On the steam engine, 360 
 
 Questions on the steam engine, 371 
 
CHEMISTRY. 
 
 INTRODUCTION. 
 
 I. DEFINITION AND OBJECT OF CHEMISTRY. 
 
 I. ALL natural sciences, that is, all human knowledge 
 about created nature, may be divided into two great classes 
 Natural History, and Natural Philosophy. 
 
 II. Natural History has for its object the systematic 
 description of animate and inanimate (living and lifeless) 
 bodies, and is again divided into Zoology, Botany, and 
 Mineralogy ; : according as the bodies described are Ani- 
 mals, Plants, or Minerals. 
 
 III. The object of Natural Philosophy is to explain 
 the various phenomena which occur in the material world, 
 by finding out their mutual relation and connection with 
 certain invariable principles, called Laws of Nature. 
 The phenomena, themselves, may have their origin in the 
 general properties of matter ; such as gravity, attraction, 
 elasticity, &c,* and consist, then, principally in motion ; 
 or they may be occasioned also by certain powers which 
 are inherent in bodies, by virtue of which one body changes 
 the form and properties of another with which it comes in 
 contact. On this account Natural Philosophy has been 
 divided into two great branches ; one which treats of the 
 Mechanical properties of matter Natural Philosophy 
 
 * See Grund's Elements of Natural Philosophy. 
 1 
 
CHEMICAL ACTION. 
 
 This double composition is exhibited by the following 
 *ki~ 
 
 table. 
 
 Saltpetre. 
 
 nitric acid, alkali. 
 
 nitrogen, oxygen, potassium, oxygen. 
 
 Query. Which, in this example, are the nearer, and which 
 the more remote ingredients of saltpetre ? J)ns. In this ex- 
 ample nitric acid and alkali are the nearer ; nitrogen, potassium, 
 and oxygen, the more remote ingredients of saltpetre. 
 
 VIII . Those substances which have not as yet been 
 decomposed by any means in our power are called Ele- 
 ments ; but it does not follow that all substances which are 
 now considered as elements, are really incapable of chem- 
 ical analysis. 
 
 Query. What then does the word Element express in 
 chemistry ? Ans. The word Element indicates only the 
 degree of our knowledge with regard to a certain substance, 
 and shows that we have not, as yet, been capable to decom- 
 pose this substance. 
 
 II. CHEMICAL ACTION. 
 
 IX. It has been observed that each chemical composi- 
 tion or decomposition, in other words, all chemical action, 
 is effected by a peculiar kind of attraction, called affinity. 
 This, therefore must be considered as the principal cause of 
 all chemical phenomena. 
 
 The changes produced on bodies which are subjected to 
 it, are principally the following. 
 
 a. A change in temperature. 
 
 EXAMPLE. Oil of vitriol and water suddenly mixed, pro- 
 duce a temperature of 212 Fahrenheit: Again, Salammo- 
 niac and snow mixed together, produce a cold equal to zero of 
 Fahrenheit's thermometer. 
 
 Hence chemical affinity changes the capacity for heat, 
 or the specific caloric of bodies. (Nat. Phil. Chap. VI.) 
 
C.HEMICAL ACTION. 5 
 
 b. A change in the physical properties of bodies. 
 
 EXAMPLE. Sulphur and oxygen are both destitute of smell, 
 taste, or action on vegetable color ; but when combined to- 
 gether they form a powerful acid, of a strong smell, which 
 changes blue vegetable colors into red. 
 
 ANOTHER EXAMPLE. Quicksilver, which is of a bright tin- 
 color, unites with sulphur, which is yellow, and forms a sub- 
 stance called cinnaber, distinguished by its beautiful red color. 
 
 c. Change in the aggregate form of bodies* 
 EXAMPLE. Oxygen and hydrogen are both aeriform,f or 
 
 gaseous, but when combined in the ratio of about 1 to 8, form 
 the well-known liquid, water. 
 
 It is not unfrequent to see chemical action accompanied by 
 light. The intensity of this light increases with the degree 
 of affinity which exists between the two combining bodies, and 
 the circumstances which favor their combination. This phe- 
 nomenon will be explained in Chap. I, when treating of oxy- 
 gen. 
 
 X. It becomes us to speak separately of the great influ- 
 ence which heat has upon all chemical phenomena. And 
 this is not only so far true, that no chemical action takes 
 place without a change of temperature ; but is founded also 
 on the fact that some combinations or decompositions are. 
 effected only through the influence of higher degrees of tem- 
 perature (when one or the other body has previously been 
 heated.) Heat, therefore is a powerful chemical agent, 
 which, in most cases, favors the chemical affinity of one 
 body for another ; although there are instances in which 
 heat seems to produce a different effect. 
 
 EXAMPLE. The process of fermentation and putrefaction 
 (see Chapter VII) requires at least 32 degrees Fahrenheit. 
 
 dgain Quicksilver combines with oxygen only when 
 heated to 2 12 degrees; and the result of this combination, 
 which is the oxide of quicksilver, separates again into quicksil- 
 ver and oxygen, when submitted to a red heat. 
 
 ANOTHER EXAMPLE. The Chloratts, a class of salts with 
 which we shall hereafter become acquainted, are decomposed 
 
 * See Natural Philosophy, Chapter I, 
 t See Natural Philosophy, 
 1* 
 
6 C.HE MI CAL ACTION. 
 
 and give off the oxygen which they contain, when thrown 
 upon live coals. 
 
 XI. The greatest obstacle to chemical action is the co- 
 hesive attraction of bodies ; that is, (as has been ex- 
 plained in Natural Philosophy) the attraction by which their 
 particles are kept together and in their relative positions.* 
 This is the reason why bodies combine readiest with each 
 other, when one or the other has been reduced to the fluid 
 state ; because the cohesive attraction is less in liquids 
 than in solid substances. It also explains why heat in- 
 creases the action of chemical affinity ; because heat, by 
 expanding all bodies (Natural' Philosophy, Chap. VI,) 
 lessens their cohesive attraction, and predisposes them for 
 the fluid state. From this the general inference has been 
 drawn, that no chemical action takes place, except one of the 
 two bodies is in the fluid state. This rule, however, is not 
 without exceptions. 
 
 Query What would take place if there were no cohesive 
 attraction to counteract the chemical affinities of bodies ? 
 Ans. Without the cohesive attraction of the particles of 
 bodies, all substances would combine and unite with each oth- 
 er to one huge mass. 
 
 Query How, then, must chemical affinity and cohesive at- 
 traction be considered in reference to each other ? Ans. 
 They must be considered as two opposite powers in nature 
 whose effects, by a wise distribution of Providence, are won- 
 derfully balanced. 
 
 XII. Bodies frequently combine with each other in 
 such a way that each of them loses its physical properties 
 in the combination. They are then said to be neutralized. 
 
 In the above example, the oxygen and the sulphur are 
 neutralized in sulphuric acid. 
 
 ANOTHER EXAMPLE. Alkali (potash) and sulphuric acid 
 are each distinguished by a peculiar taste ; potash changes 
 blue vegetable colors into green, and sulphuric acid turns 
 them into red. By mixing these substances in the proper 
 proportion, we obtain a salt destitute of either acid or alka- 
 line qualities ; its taste being bitter, and the salt itself be- 
 ing without any effect on vegetable colors. 
 
 * See Natural Philosophy, Chapter I. 
 
CHEMICAL ACTION. 7 
 
 Query In what state are the potash and the sulphuric 
 acid, in this case, contained in the salt? JJns. They are 
 neutralized in it. 
 
 It may be well to observe here, that in order to effect a 
 complete neutralization, the two bodies must combine in a 
 certain fixed proportion, before or beyond which no such phe- 
 nomenon takes place. 
 
 XIII. Some bodies combine with each other in all pro- 
 portions, and preserve still a portion of their original 
 properties. Such a combination is more properly called a 
 mixture. 
 
 EXAMPLE. If wine and water be poured together, a mix- 
 ture is obtained in which the fluidity of both liquids, as well 
 as some of the taste and color of the wine is preserved. The 
 same is the case when vinegar and water, alcohol and water, 
 alcohol and wine, &c, are poured together. 
 
 XIV. Whenever we wish to decompose a chemical com- 
 pound into its constituent parts, we must have recourse to 
 a third substance, with which one of these parts is to com- 
 bine, by which means the other becomes disengaged or free. 
 This kind of chemical attraction, in consequence of which 
 a body quits a combination already existing, for the sake of 
 forming a new one, is called Elective affinity; because 
 the body seems, as it were, to elect one combination in 
 preference to another, which it has already formed. 
 
 EXAMPLE. Muriate of lirne is a compound of muriatic acid 
 and lime ; but when potash is added to the solution the muri- 
 atic acid combines with the potash, and the lime being now- 
 disengaged falls to the bottom, and forms what is called a 
 precipitate. This process may be represented to the eye by 
 the following figure. 
 
 Muriate of Potash. 
 
 C Muriatic acid. Potash, 
 
 Muriate of Lime. < 
 
 (| Lime. 
 
 The original compound (Muriate of Lime) is composed of 
 Muriatic acid and lime. As soon as potash is added, the mu- 
 riatic acid combines with the potash, and forms muriate of pot- 
 ash ; and the lime becomes free, 
 
CHEMICAL ACTION. 
 
 Query What substance, in this example, shows an elect- 
 ive affinity for Potash ? Jlns. The muriatic acid. Query 
 Why ? Ans. Because it quits its combination with lime, 
 and unites, as it were, in preference with the potash. 
 
 XV. When a solid body combines with a fluid, the 
 product is called a solution. In this case the affinity be- 
 tween the two substances continues to act only to a certain 
 point, that is, the liquid is only capable to dissolve a cer- 
 tain portion of the solid so that if we wished to have a 
 greater quantity of the solid dissolved, we should have to 
 add more of the liquid. The point beyond which the affin- 
 ity of the liquid ceases to act upon the solid, is called the 
 point of saturation ; and the solution itself, when arrived 
 at this point, is said to be saturated. 
 
 EXAMPLE Water will dissolve only a certain quantity of 
 sugar or salt, until it becomes saturated. A fresh quantity 
 of sugar or salt being then added will remain unchanged at 
 the bottom of the vessel. But if a new quantity of water be 
 added to the solution, then a new quantity of sugar or salt 
 will be dissolved. 
 
 XVI. The saturation of liquids depends principally 
 
 1. Upon the temperature of the liquid. 
 
 2. Upon the degree of affinity which exists between the 
 liquid and the solid ; and 
 
 3. Upon the purity of the liquid. 
 
 The warmer the liquid is, the more can it generally dis- 
 solve of a given solid. To this rule, however, there are 
 several exceptions. 
 
 EXAMPLE. Water of the temperature of 212 Fahrenheit, 
 will dissolve no more common salt, than water of the tempera- 
 ture near the freezing point. Water of the temperature of 
 212 dissolves even less magnesia, than water of the common 
 temperature of the atmosphere. But with regard to most 
 salts the solving power of water increases with the tempera* 
 ture. 
 
 XVII. It frequently occurs that a compound of two 
 substances cannot be decomposed without the assistance 
 of a third and fourth substance. The affinity of the 
 third substance for any one of the constituent parts of the 
 
CHEMICAL ACTION. 9 
 
 compound, is then, of itself, not sufficient to produce a sep- 
 aration. This kind of affinity is called Double or Complex 
 affinity. It will be best understood from the following 
 
 EXAMPLE. 
 
 Zinc decomposes water (which is a compound of oxygen 
 and hydrogen) only when an acid is added. The hydro- 
 gen of the water then becomes free, while the zinc and 
 oxygen combine together with the acid to form a salt. 
 The zinc, of itself, is not capable of separating the oxygen 
 from the hydrogen ; but the acid having a strong affinity 
 for a combination of zinc and oxygen, predisposes the oxy- 
 gen to quit its combination with water and to combine with 
 the zinc. For an illustration, see the following table : 
 
 ( hydrogen, 
 Water, J 
 
 ( oxygen, 
 
 >xygen, } 
 
 > oxide of zinc, 1 
 zinc, ) \ salt, 
 
 acid ) 
 
 Zinc alone does not separate the oxygen from the hy- 
 drogen; but when the acid is added, which has a strong 
 affinity for the oxide of zinc, this latter substance (oxide of 
 zinc) is formed, and combines with the acid to salt. 
 
 Some philosophers ascribe these phenomena to a predispos- 
 ing affinity ; because the acid, in our first example, seems to 
 predispose the oxygen for a combination with the zinc. 
 
 Query What substance, in this example, has exercised 
 a predisposing affinity upon oxygen? Jlns. The acid. 
 Query Why ? Jlns. Because it has disposed it for a 
 combination with the zinc. Query But by what means doea 
 the acid predispose the oxygen for a combination with the 
 zinc ? Jlns. By the strong affinity which it has for the 
 oxide of zinc, which is a combination of the oxygen with 
 zinc. 
 
 XVIII. If two compounds be brought together in a 
 state of solution, it frequently happens that a double de- 
 composition, and two new compositions take place. Both 
 the original compounds are then decomposed, and two new 
 compositions are formed by a mutual interchange of in- 
 gredients. Such a compound action is said to be caused 
 by double elective affinity. 
 
10 CHEMICAL ACTION. 
 
 EXAMPLE. The well known substance, sugar of lead, 
 (which is used as a paint) is composed of acetic acid (vinegar) 
 and lead. White vitriol is a compound of sulphuric acid and 
 zinc. Now if a solution of sugar of lead be mixed with a so- 
 lution of white vitriol, the acetic acid will quit its combination 
 with lead, and unite with the zinc ; while, at the same time, 
 the sulphuric acid which is set free, unites with the lead and 
 forms an insoluble hard powder (sulphate of lead) which 
 is precipitated. For an illustration see the following dia- 
 gram. 
 
 Acetate of zinc, 
 
 C Acetic acid, Zinc, } 
 
 Sugar of Lead, 3 V White Vitriol, 
 
 ( Lead, Sulphuric acid, ) 
 
 Sulphate of lead. 
 
 The original compounds, sugar of lead and white vitriol, are 
 placed at the extremities of the two brackets ; their respective 
 ingredients, acetic acid and lead, and zinc and sulphuric acid, 
 are placed inside of the brackets ; the new compounds, ace- 
 tate of zinc, which is formed by the combination of the acetic 
 acid with the zinc is placed above the upper, and the second 
 compound, sulphate of lead, formed by the combination of the 
 lead with the sulphuric acid, is placed under the lower bracket. 
 
 Query Which substance does the acetic acid, in this ex- 
 ample elect in preference to the lead with which it was com- 
 bined ? Ans. The zinc, with which it combines, setting 
 lead free. Query And which substance does the sulphuric 
 acid elect in preference to the zinc ? ./7ns. The Lead, giv- 
 ing off the zinc with which it was united. Query And 
 why is this action called double elective affinity ? Jlns. Be- 
 cause two distinct elections took place, viz. the acetic acid 
 elects the zinc, and the sulphuric acid the lead, for a new 
 combination. 
 
 This kind of affinity often effects the decomposition of 
 a substance which would have resisted the action of single 
 elective or predisposing affinity. 
 
 XIX. It has been said that while some bodies combine 
 with each other in all proportions and form mixtures, others 
 have a limit to their combination, which is the point of 
 SATURATION. But there are substances which combine 
 with each other only in certain Jixed proportions, that is, 
 
CHEMICAL ACTION. 11 
 
 so many parts or weights of one substance, with a definite 
 number of parts or weights of another. The product of 
 such a combination is always a compound in which the 
 properties of the constituent parts are completely neutral- 
 ized. (See XII.) 
 
 EXAMPLE. Sulphur and oxygen are apparently heteroge- 
 neous substances ; oxygen is a gas, and sulphur a solid body. 
 These two substances however unite with each other in the 
 proportion of 16 weights of sulphur with 24 weights of oxygen, 
 in which case they form a compound which is known by the 
 name of sulphuric acid ; and whose properties are totally dif- 
 ferent from those of the sulphur or oxygen ; these are therefore 
 neutralized by the combination. 
 
 Some bodies combine with each other only in one pro- 
 portion ; others combine in two, three, four and more fix- 
 ed ratios. 
 
 EXAMPLE. Zinc and oxygen combine with each other only 
 in one proportion, forming what is called oxide of zinc ; but the 
 two gases, known by the name of oxygen and nitrogen, com- 
 bine with each other in five distinct ratios, viz. 
 
 I volume of nitrogen with 1 volume of oxygen, 
 
 1 u it it it O tt it it 
 j it tl tl it 3 it ti it 
 J tl tt it it ti ti n 
 
 and 1 " " " " 5 " " " 
 
 the five resulting combinations being two oxides and three 
 acids of nitrogen, and there are no other combinations of these 
 two substances known. 
 
 Similar fixed ratios have been discovered in the com- 
 bination of other bodies to definite compounds, and it has 
 been observed that in these combinations the original prop- 
 erties of the ingredients are always completely neutralized, 
 so that we are able to lay down the general principle : No 
 two bodies combine with each other to neutralization, except 
 in ajixed determined proportion, which remains always the 
 same, for the same two substances. 
 
 Now it has been remarked and proved by numerous ex- 
 periments, that if a body, A, combines with another body, 
 B, for instance, in the ratio of 1 weight of A with 2 
 weights of B ; and the same body A , combines with a third 
 body, C, in the ratio, say of I weight of A, to 3 of C, then 
 the body, B, will, if it have any neutralizing affinity for 
 
12 CHEMICAL ACTION. 
 
 the body C, combine with it in the ratio of 2 to 3, or at 
 least in a multiple of this ratio by a whole number ; that 
 is in 2, 3, 4, 5 or 6 times this ratio ; so that the ratio in 
 which one and the same body, A, combines to neutralization 
 with different bodies, B, C, D, 4*c, being once known, the 
 neutralizing ratio in which these bodies combine with each 
 other are also determined This will be better understood 
 by the following EXAMPLE. 
 
 (2 Ibs. ofB, 
 
 Supposing 1 Ib. of a substance A. combines with ( ^ ^ ^ p' 
 
 [ 5 Ibs. of E; 
 then the relation of the substance, A, to the bodies, B, C, 
 
 D, E, determines also that of the bodies B, C, D, and E 
 to each other ; viz. if the body, B, has a neutralizing 
 affinity for C, D, and E, it will combine with them in the 
 ratio of 
 
 ( with 3 Ibs. of C, 
 
 2 Ibs of B { with 4 Ibs. of D, 
 
 ( with 5 Ibs. of E. 
 
 Further, if C, has any neutralizing affinity for C, D, 
 and E, it will combine with them in the ratio of 
 
 !2 Ibs. of B, 
 4 Ibs. of D, 
 5 Ibs. of E. 
 
 If D have any such affinity for B, C, and E, it will 
 combine with them in the ratio of 
 
 ( 2 Ibs. of B, 
 
 4 Ibs. of D with { 3 Ibs. of C, 
 
 ( 5 Ibs. of E, 
 
 And lastly if E have this affinity for B, C, and D, it 
 will combine with them in the ratio of 
 
 r 2 Ibs. of B, 
 
 5 Ibs. of E with ! 3 Ibs. of C, 
 
 ( 4 Ibs. of D. 
 
 Thus a single table expressing the fixed proportions in 
 which the body A, combines respectively with B, C, D and 
 
 E, has given us at once the fixed proportions in which B, 
 C, D, and E combine with each other. 
 
CHEMICAL ACTION. 
 
 13 
 
 The learner will now be able to understand the follow- 
 ing example, which is taken from nature : 
 
 We know from experience that 
 
 37 weights of Muriatic acid combine with 28 of Lime, 
 40 " " Sulphuric acid " " 48 " Potass, 
 54 " " Nitric acid " " 32 " Soda, 
 
 28 " {< Phosphoric acid ' " 17 " Ammonia. 
 
 These ratios give not only the proportions in which each 
 of these substances combines with that which is placed on 
 the same line with it ; but also the proportion in which 
 each of these substances combines with all others. Thus, 
 
 28 weights of Lime, 
 
 with 
 
 37 weights of muri- 
 atic acid combine to 
 saturation 
 
 40 weights of Sul- 
 phuric acid combine 
 to saturation 
 
 54 weights of Nitric 
 acid combine to sat- 
 uration 
 
 with 
 
 with 
 
 48 
 32 
 17 
 
 Potass. 
 
 " Soda, 
 
 " Ammonia, 
 
 28 weights of Lime, 
 48 " " Potass, 
 32 " Soda, 
 17 " " Ammonia, 
 
 28 weights of Lime, 
 48 " " Potass, 
 32 " " Soda, 
 17 " " Ammonia. 
 
 Or we could also take any of the four substances, Lime, 
 Potass, Soda, or Ammonia ; say soda, and write the four 
 acid substances after it, viz. 
 
 37 weights of Muriatic acid, 
 
 40 " " Sulphuric acid, 
 
 54 
 
 28 
 
 Nitric acid, 
 Phosphoric acid, 
 
 32 weights of / 
 Soda combine to / with 
 saturation \ 
 
 and so on. 
 
 Now as 37 weights of muriatic acid combine in the 
 same proportions with Lime, Potass, Soda, and Ammonia, 
 in which 40 weights of sulphuric acid combine with 
 these substances, 37 weights of the first acid are said to be 
 equivalent to 40 weights of the second; and accordingly, 
 also to 54 weights of Nitric, and to 28 weights of Phospho- 
 ric acid. In like manner are 28 weights of lime equiva- 
 2 
 
14 CHEMICAL ACTION. 
 
 lent to 48 weights of potass, 32 of Soda, 17 of ammonia. 
 Or we may also say that 37 weights of muriatic acid are 
 equivalent to 28 weights of lime, 48 of potass, 32 of soda, 
 &c, or that 28 weights of lime are equivalent to 37 weights 
 of muriatic, 40 of sulphuric, 54 of nitric, and 28 of phos- 
 phoric acid, and so on. 
 
 We shall show in the body of the following work that 
 similar equivalent numbers have been found for a great 
 many substances in the chemical catalogue ; and it is by 
 these numbers that we are able to express the definite pro- 
 portions in which one substance combines tvith all others, 
 for which it has a strong chemical affinity. The smallest 
 number of weights of one substance which in this manner 
 combines with other substances, is said to be a CHEMICAL 
 EQUIVALENT for all other substances with which it is ca- 
 pable of entering into combination. 
 
 Now it has been found by experiments that in all cases 
 where a body is composed of two elements, the sum of 
 the equivalents of the elements is equal to the equivalent 
 of the body itself. Knowing therefore the equivalent of 
 the elements of a body, we also know that of the com- 
 pound ; and the reverse, if the equivalent of the compound 
 and the elements of its composition are known, the equiv- 
 alents of its elements may be inferred from it. This will 
 be better understood from the following 
 
 EXAMPLE. 1 weight of hydrogen combines with about 
 8 weights of oxygen to water. Consequently if 1 weight 
 of hydrogen gas is taken for unity of comparison, the 
 equivalent of oxygen will be 8 ; whence that of water will be 
 1 added to 8, equal to 9. And the reverse ; suppose we 
 know that the chemical equivalent, of water is 9 ; and that 
 it is composed of I equivalent of water and 1 of oxygen. 
 Knowing the equivalent of water to be = 9, we should at 
 once infer that of the oxygen, which must be equal to 8. 
 
 ANOTHER EXAMPLE. One weight of hydrogen com- 
 bines with 16 weights of sulphur, to sulphuretted hydrogen ; 
 consequently the weight of hydrogen taken for unity, the 
 chemical equivalent of sulphur is 16. Now the chemical 
 equivalent of oxygen being 8, it is known that 2 equiva- 
 lents of oxygen combine with 1 equivalent of sulphur to 
 
CHEMICAL ACTION. 15 
 
 sulphurous acid. Query What is the equivalent num- 
 ber of sulphurous acid ? Ans. 32. Query Why ? 
 Ans. Because it is composed of 1 equivalent of 
 
 sulphur = 16 
 and of 2 equivalents of oxygen (each equal to 8) = 16 
 
 Consequently, Chemical equivalent of sulphurous 
 
 acid = 32 
 
 Jigain Supposing we know the chemical equivalents 
 of sulphurous acid = 32, and also that it is composed of 
 1 equivalent of sulphur, and 2 equivalents of oxygen, 
 (each equal to 8.) Required the chemical equivalent of 
 sulphur. Ans. The equivalent of sulphurous 
 
 acid being = 32 
 Subtract from it 2 equivalents of oxygen (each 
 
 equal to 8) = 16 
 
 The remainder will be the equivalent of sulphur = 16. 
 
 These few examples will be sufficient to show the beau- 
 ty and harmony of the theory of chemical equivalents ; 
 as well as the advantages which the practical chemist may 
 derive from it. 
 
 Were the chemical equivalents of all bodies unchangeable, 
 and as correctly determined as those we have mentioned in 
 our last examples, then it would indeed be possible to intro- 
 duce mathematical precision and certainty into the science of 
 chemistry, which would then in no respect yield to any of the 
 exact sciences. A single experiment which should show the 
 relation of an unknown substance to one with whose proper- 
 ties we are already acquainted, would suffice to determine the 
 relation of that substance to all other bodies ; which relation 
 would, in most cases, be found by a mere addition or subtrac- 
 tion, as has been shown in the last two examples. But this is 
 far from being universally true. The same limits with which 
 the human understanding invariably meets in all sciences, 
 await us also in chemistry. For the proportion in which 
 bodies combine are not always as definitely pronounced as we 
 could wish them to be. In some bodies they are less percep- 
 tible than in others, and there are substances whose composi- 
 tion is so vague and indefinite that thus far, it has been impos- 
 sible, even by the nicest experiments, to fix upon any of their 
 supposed definite equivalents. We know farther, from expe- 
 rience, that 1 equivalent of one body, does not always combine 
 again with 1 equivalent of another ; on the contrary it has 
 
16 CHEMICAL ACTION. 
 
 been found that 1 equivalent of one body frequently combines 
 with 1, li, 2, 3, or 5 equivalents of another ; and there are ex- 
 periments and facts, which have induced some of the best 
 chemists now living to suppose that one equivalent of one sub- 
 stance may also combine with 4-, ^, f ;, ^ and even 
 equivalent of another substance. Hence the universal advan- 
 tage which it was hoped would be obtained from a numerical 
 computation of chemical equivalents has, thus far, not been 
 realized. For although we may be able to investigate by 
 experiment the proportion of matter or weight in which two 
 substances combine with each other, yet will this investigation 
 not always lead us to a precise result as regards the chemical 
 equivalent of the compound ; because we do not always know 
 whether 1, , 2, or one fourth, one third, two thirds, one eighth, 
 or one sixth equivalent of either substance is combined with 
 one equivalent of the other. But as far as the whole theory of 
 Chemical proportions is supported by actual experiments, it not 
 only serves to facilitate the labors and to assist the memory of 
 the practical chemist; but deserves also, on account of its 
 harmony with other laws of nature, to be ranked among the 
 most brilliant discoveries of the human mind. 
 
 The chemical equivalents of a great number of substan- 
 ces, as far as we have been able to determine them by ac- 
 tual experiments (but in most cases unfortunately only by 
 arithmetical computation), have been arranged in tables, 
 of which one is attached to the end of the book. From 
 what we have said it will easily be seen that they are not 
 in all cases to be relied upon with mathematical certainty, 
 although many authors speak of them as established facts, 
 or consider the whole theory established beyond any rea- 
 sonable doubt. In most of these tables the weight of t 
 equivalent of hydrogen gas is taken for unity of compar- 
 ison. The same is done in our table, for reasons which 
 we shall explain hereafter when treating of hydrogen gas. 
 The full development of the theory of chemical equiva- 
 lent cannot be given here (in the introduction to chemis- 
 try) ; nor can it be expected that the pupil shall have an 
 adequate idea of it from the few statements of facts which 
 we have made in this section. But we shall revert to this 
 subject again, and give a more complete exposition of it, 
 as we go along, treating separately of the most important 
 substances of the chemical catalogue. 
 
CHEMICAL APPARATUS. 
 
 17 
 
 III. CHEMICAL APPARATUS. 
 
 [It is to be understood that only the most useful and essen- 
 tial apparatus, which may be easily procured, can find a place 
 in an elementary treatise for schools. A complete description 
 of it is found in Berzelius's Chemistry, Vol. 1.] 
 
 XX. a. Apparatus for dividing bodies. 
 Fig. I. 
 
 These consist of mortars 
 and pestle, (Fig. I.) 
 
 hammer and anvil, (Fig. II.) 
 
 Fig. III. 
 
 Fig. IV. 
 
 knives, (Figs. Ill, 
 IV and V.) 
 
18 
 
 CHEMICAL APPARATUS. 
 
 
 Fig. VI. 
 
 Jiles, (Fig. VI,) &c, the construc- 
 tion of which is sufficiently plain from the diagrams. 
 
 b. Apparatus for separating liquids from solids. 
 Fig. VII. 
 
 To these belong sieves, (Fig. VII.) 
 
 Fig. VIII. 
 
 cullenders, (Fig VIII.) 
 
 Fig. IX. 
 
 straining cloths, (Fig. IX.) 
 
CHEMICAL APPARATUS. 
 Fig. X, Fig. XI. Fig. XII- 
 
 19 
 
 Fig. XIII. Fig. XIV. 
 
 funnels, (Fig. X, 
 XI, and XII.); 
 &c. 
 
 The decanting jar is repre- 
 sented in Figs. XIII and XIV. 
 Its shape is sufficiently plain 
 from the figure, and its applica- 
 tion in the pouring of liquids, 
 easily understood. 
 
 Fig. XV. Fig. XVI. 
 
 Fig. XVII. 
 
 A spherical or common glass 
 bottle, (Figs. XV and XVI,) 
 with a small cylindrical tube, 
 fixed air-tight in the cork, 
 serves to separate a liquid from a 
 solid by the process of evapora- 
 tion (explained in Natural Phi- 
 losophy). 
 
 To separate a lighter rluid from a specific 
 heavier one, the separatory funnel (Fig. 
 XVII) is used, which opens upwards and 
 downwards. When the lighter fluid is de- 
 canted through the upper aperture the spe- 
 cific heavier descends through the lower. 
 
20 
 
 CHEMICAL APPARATUS. 
 Fig. XVIII. 
 
 The operations of the syphon has already been described 
 in Natural Philosophy, Chapter V. 
 
 c. Apparatus for the liquefaction of solids. 
 Fig. XIX. Fig. XX. 
 
 These consist of melting 
 pots, (Fig. XIX,) or cru- 
 cibles, (Fig. XX,) made 
 of earthen ware, silver or 
 platinum ; 
 
 of glass vessels called matrasses, of 
 which one is represented in Fig. XXI. 
 
 of porcelain saucers and spoons, 
 (Figs. XXII,) for stirring acids 
 which would effect metal or 
 glass, &c. 
 
 Fig. XXL 
 
CHEMICAL APPARATUS. 
 
 21 
 
 d. Apparatus for evaporation and crystalization. 
 Both processes have been described in Natural Philosophy. 
 XXI. For this purpose we make use of what are called 
 
 Fig. XXIII. 
 
 Fig. XXIV. 
 
 evaporating dishes, made of 
 porcelain, glass, or silver. (See 
 Fig. XXIII.) Their form must 
 be flat, to present the greatest 
 possible surface to the atmos- 
 phere. When the process of 
 evaporation takes place under 
 the influence of heat it is 
 called a steam-bath. For 
 this purpose a flat vessel, 
 made of wedgewood ware, is 
 bedded in hot sand or ashes. 
 (See Fig. XXIV.) 
 
 e. Apparatus for distillation. 
 
 XXII. This is a contrivance for collecting the volatile 
 
 Fig. XXV. 
 
 portion of a body which es- 
 capes through the process of 
 evaporation. The most com- 
 mon is an alembic, (Fij 
 XXV,) composed of a flasl 
 (which may be bedded in 
 sand) the head of which fits 
 air-tight in the neck of the 
 pipe, which is destined to carry 
 the rising gas from the flask 
 into the receiver. 
 
22 
 
 CHEMICAL APPARATUS. 
 Fig. XXVI. 
 
 The common still, (Fig. XXVI,) an instrument 7 sim- 
 ilar in its construction to an alembic, is made of cop- 
 per. It is shaped like a kettle, A, and has a hollow mov- 
 able head, B, to which a pipe, C, is attached, leading to a 
 spirally formed tube, commonly called the worm, which 
 for the purpose of cooling, may be immersed in water. 
 The vapours then contained in it are, by this means, con- 
 densed, and descend in drops when the cock, E, is opened. 
 Fig. XXVII. 
 
 The" instrument more gen- 
 erally employed for distillation 
 is a retort. It may be made 
 of glass, porcelain, or metal ; 
 and is either as shaped in Fig. 
 XXVII, or as represented in 
 Fig. XXVIII. There is al- 
 ways a receiver, R, con- 
 nected with it, which in 
 some instances is again 
 provided with a pipe and 
 stop-cock, to let off the 
 distilled liquid at differ- 
 ent periods. The ope- 
 ration of this apparatus is easily understood. When the 
 liquid which is heated in the retort, A, evaporates, the 
 volatile parts are collected by the receiver, R. 
 
CHEMICAL APPARATUS 
 
 Fig. XXIX. 
 
 A Florence flask (Fig. XXIX,) with 
 a pipe fixed air-tight through its cork, 
 is a cheap apparatus, answering most 
 purposes for which retorts are used. 
 The pipe, A, may be connected with 
 a receiver, as in Figs. XXV [I, and 
 XXVIJI. 
 
 f. Apparatus for heating Chemical substances. 
 X XIII. These consist in lamps and furnaces. 
 Fig. XXX. Fig. XXXI. 
 
 The latter are either portable air furnaces with crucible 
 stands (Figs. XXX, and XXXI) ; or they are fixed wind- 
 furnaces of which one is represented in Fig. XXXII. 
 Fig. XXXII. 
 
24 CHEMICAL APPARATUS. 
 
 Both kinds of furnaces are so constructed that the air 
 has free access to the fire from below. By this means a 
 continued draught is created, which, as we shall see here- 
 after, is necessary for a brisk flame or free combustion. 
 For the heated air in the furnace becomes specifically 
 lighter and escapes through the upper opening, while the 
 outer air rushes from below in its place. (See Natural 
 Philosophy, Chap. V.) 
 Fig. XXXIII. 
 
 Figs. XXXIII, XXXIV, and XXXV, 
 represent the three principal kinds of 
 lamps used for chemical purposes. Fig. 
 XXXIII represents the common lamp. 
 A combustible substance, usually made 
 of cotton, called the wick, is immersed 
 in oil, with which the whole apparatus 
 is filled, and is then lighted. The 
 flame, nourished by the oil, which as- 
 cends through the wick and is gradually consumed, throws 
 out heat and light at the same time. 
 Fig. XXXIV. 
 
 Fig. XXXIV represents a spirit 
 lamp. The main difference be- 
 tween this lamp and the one just 
 described, consists in spirit of wine 
 being employed instead of oil, 
 the heat of the flame of this sub- 
 stance being much more intense 
 than that produced by the flame of a common oil lamp. 
 
 Fig. XXXV. 
 
 Fig. XXXV represents an Argand 
 lamp, with its stand. This is as great 
 an improvement upon common lamps 
 as the wind-furnace upon a common 
 fire-place. Its principal advantage over 
 a common lamp consists in a round 
 hollow wick through which the air is 
 admitted by an opening from below, 
 causing thereby a much more perfect 
 combustion, and throwing out much 
 more light and heat than is done by a common lamp, 
 
CH.EMICAL APPARATUSj. 
 
 25 
 
 where the air comes only in contact with the exterior 
 part of the flame. The flame of the Argand lamp is 
 moreover covered by a round open glass, which serves it 
 in the office of a chimney, through which the heated air 
 ascends and is replaced by the air which enters from be- 
 low ; the draft thereby created tending not a little to in- 
 crease the intensity and heat of the flame. 
 Fig. XXXVI. 
 
 A convenient contrivance 
 for heating bodies in a retort, 
 is Guiton's Lamp-furnace. 
 It consists of an iron or brass 
 rod, O P, with several slid- 
 ing sockets, which serve to 
 support the lamp, A, and the 
 arms, LF, OG, of which 
 there may be as many as 
 may be thought expedient. 
 The arms terminate in iron 
 or brass rings for the sake 
 of supporting retorts and 
 receivers, (see the figure) 
 |T or in small forceps to hold 
 the body which is to be ex- 
 posed to the heat of the 
 lamp. These arms may, by 
 means of sockets, be moved 
 up and down the rod, O P, or turned sideways, and then 
 screwed fast to any particular part of it, as the experiment 
 may require ; and the same may be done with the lamp, 
 in order to regulate the heat. The whole apparatus is 
 best fastened to a table, T, by means of a screw, B, in or- 
 der to give more steadiness and security to the experiment. 
 Fig. XXXVII. 
 
 For the sake of producing a very intense heat 
 with a common oil or spirit-lamp, an instrument is 
 used which is called a common blow-pipe. It con- 
 sists of a bent brass tube, whose upper end is from 
 one third to one half inch in diameter ; but is grad- 
 ually tapering to a point, as is represented in figure 
 XXXVII. When the lower (bent) end is placed 
 in the flame of the lamp and the upper is applied 
 
CHEMICAL APPARATUS. 
 
 to the mouth or nostrils, a stream of air may be applied 
 to the jet of the flame for the double purpose of giv- 
 ing it a horizontal direction, and making it gradually 
 taper to a point, to which the body that is to be heat- 
 ed must then be exposed. The body must be placed upon 
 a piece of charcoal, which may be held by small forceps. 
 (See fig. L. page 32.) 
 
 Fig. XXXVIII. 
 
 An improvement upon the 
 common blow-pipe, is Gahn's 
 blow-pipe, (Fig. XXXVIII.) 
 which instead of the bent tube is 
 provided with the chamber A, to 
 which the smaller orificed pipe, 
 B, is attached. The advantage 
 of this apparatus consists in the 
 chamber, A, retaining the mois- 
 ture from the breath, which, 
 when the common blow-pipe is 
 used, often stops the process, or 
 diminishes the flame. 
 
 Fig. XXXIX. 
 
 A more convenient contrivance than either is that rep- 
 resented in Fig. XXXIX. where the blow pipe C, commu- 
 nicates with a bellows A, which may be moved with the 
 foot by placing it upon the board, B, and by which means 
 
CHEMICAL APPARATUS. 
 
 27 
 
 a constant stream of air is sent through the jet of the flame, 
 D. This apparatus is particularly used for closing the 
 tubes of barometers and thermometers, and such similar 
 purposes. 
 
 g. Apparatus for compressing bodies, or extracting liquids 
 
 from bodies in which they are contained. 
 Fig. XL. 
 
 XXIV. For the purpose of extract- 
 ing liquids from solids in which they 
 are contained, two kinds of presses 
 are used ; one with one screw only, 
 (Fig. XL.) and the other with two, 
 (Fig. XLI.) The press with one screw 
 consists chiefly of an iron arch, A, fas- 
 tened to a block of wood, B, and con- 
 taining in C the nut through which the 
 screw, D, moves up and down. The 
 substances contained in the basin, E, are by this screw 
 compressed, and the liquid descends through the nose, F. 
 Fig. XLI. 
 
 The press with two screws (Fig. XLI.) consists of two 
 boards, A and B, which are brought together by the two 
 screws, C, C, and by this means compress the substances 
 which are placed between them. The remainder of the 
 construction is similar to the press with one screw. 
 
28 
 
 CHEMICAL APPARATUS. 
 
 Fig. XLI1. 
 
 When a solid substance is to be dis- 
 solved in a liquid, an instrument is often 
 used, which is called the hydrostatic, or, 
 from its inventor, Count Real's press. 
 It consists of a strong tin barrel, A B, 
 which in C is provided with a fine sieve, 
 and in D, with a discharging spout. The 
 upper part screws into a metallic cover 
 E, which terminates in a long narrow 
 tube, and is, in I, provided with a stop- 
 cock. The solid substance from which 
 an extract is to be made, is first put in the 
 barrel and placed upon the sieve C ; on 
 top of it is placed a tin plate, K, which 
 like the sieve, C, is provided with a great 
 many fine holes ; the cover is then screw- 
 ed upon the barrel, and the narrow tube, 
 G H, filled with the liquid which is to 
 be employed for the solution of the solid. 
 The solving power of the liquid is pro- 
 digiously increased by the hydrostatic 
 pressure of the liquid, (see Natural 
 Philosophy, Chapter VI) which by this 
 means forces its way through the solid 
 substance between K and C, and collects 
 in the lower part, B, of the barrel, whence 
 it may be drawn off by the discharging 
 spout, D. 
 
CHEMICAL APPARATUS. 29 
 
 Fig. XLIII. 
 
 The pressure of liquids is also taken advantage of in 
 the construction of Brahma's hydraulic press. It consists 
 of a large pump barrel, A, B, C, D, which communicates 
 with a small forcing pump, M N. The two pistons, P, P, 
 work water tight in their respective barrels. The whole 
 space between the two pistons is filled with water. The 
 substance to be pressed is placed upon the top, A B, of 
 the large piston, above which a strong fixed surface, F G, 
 is made to meet the pressure. When the small piston is 
 forced down by means of the lever, E, the water exercises 
 a pressure upon the lower end, C D, of the large piston, 
 P, which will be as many times greater than the force with 
 which the small piston is worked down, as the surface of 
 the larger piston is larger than the surface of the smaller 
 one. Thus, if the surface of the smaller piston be one 
 square inch, and that of the larger one square foot, then 
 the pressure on the upper piston will be 144 times greater 
 than the force which pressed the smaller piston down* 
 Hence one man working on the lever, E, may exercise 
 pressure upon the piston, P, equal to that which it would 
 take 1 44 men of the same strength to produce, if directly 
 working upon C D. If the surface of the smaller piston 
 were only one fourth of a square inch, then the pressure 
 upon C D upwards would be 4 times 144, or 576 times 
 greater ; and so on. Now it is easily seen that the greater 
 the power is, which presses the piston P, upwards, the 
 
 3* 
 
30 
 
 CHEMICAL APPARATUS. 
 
 greater will be the pressure exercised upon the body 
 which is placed between the two surfaces, A B, and F G ; 
 whence the utility of this apparatus follows of course. 
 
 7i. Apparatus for collecting gases. 
 
 XXV. For collecting gases an apparatus called the 
 Pneumatic tub, water, or quicksilver bath, is employ- 
 ed. It consists of a tub, A, (see the figure) in which a 
 Fig. XLIV. 
 
 shelf is fixed in such a manner, that the liquid, common- 
 ly water or quicksilver, may rise two or three inches above 
 it. Ajar or receiver, B, filled with the same liquid is placed 
 upon this shelf, (which for this purpose must be provided 
 with several holes) with its mouth downward. The pipe, 
 C, conducts the gas which is forming in the retort, D, to 
 the jar, B, in which it rises in little bubbles, expelling 
 thereby the liquid of which it takes the place. 
 Fig. XLV. 
 
 Another apparatus for collecting gases is 
 Priestley's bell-glass. (Fig. XLV.) This 
 useful apparatus consists of a bell glass, A, the 
 neck, B, of which may be closed or opened 
 by means of the stop-cock, C. This con- 
 trivance is very convenient for the collect- 
 ing of gases, because in order to fill it with 
 water or quicksilver, it is only necessary to 
 open the stop-cock, C, and immerse the 
 glass perpendicularly in the liquid. As the glass fills 
 with the liquid, the air escapes through the neck, B D. 
 Its principal use however consists in transferring gases 
 
CHEMICAL APPARATUS. 
 
 31 
 
 from one vessel to another ; for which purpose the gas 
 which escapes through the neck, B D, need only be col- 
 lected by a receiver. 
 
 Fig. XLVI. 
 
 Another application of this apparatus is 
 made by filling a bladder (Fig. XLVI.) 
 with a particular gas that may be contained 
 in the bell-glass. This, as we shall see 
 hereafter, is very desirable for the sake of 
 certain experiments. The bladder, L, 
 (Fig. XLVI.) must for this purpose be 
 tied air-tight to a brass tube, G H, which 
 by means of the stop-cock, F, may be clos- 
 ed or opened at pleasure, and in G is made 
 to screw to the extremity, D, of the neck 
 of the bell-glass. When this is done, 
 and the two cocks, G and F, are opened, the bell-glass 
 (Fig. XLV.) needs only be perpendicularly immersed in 
 quicksilver or water, and the gas will escape through the 
 neck into the bladder. When the bladder is rilled, the stop- 
 cock F, is closed, and the barrel G H, unscrewed from 
 the bell-glass. It is also common to provide the bell, A, 
 with a scale S, (see the last figure) in order to estimate 
 the volume of gas which escapes by the rise of the quick- 
 silver or water in the bell-glass. 
 
 i. Apparatus necessary for various chemical purposes. 
 Fig. XLVII. 
 
 XXVI. To these we reckon 
 stands, (Fig. XLVII.) 
 
32 CHEMICAL APPARATUS. 
 
 Fig. XLVIII. 
 
 Fig. XLIX. 
 
 Fig. L. 
 
 Fig. LI. 
 
 Fig. LII. 
 
 Fig. LIII. 
 
 Fig. LIV. 
 
 shears, (Fig. XLIII.) 
 
 pincers, (Fig. XLIX.) 
 
 forceps, (Fig. L.) 
 
 plates, (Fig. LI.) 
 
 cylindrical glasses, (Fig. LII.) 
 
 glass tubes, (Fig. LIII.) 
 
 tubs, (Fig. LIV.) 
 
UHEMI|CAL APPARATUS. 
 
 Fig. LV. 
 
 bellows, (Fig. LV. ) 
 
 and especially accurate beams and scales (Figs. LVI, 
 LVII, and LVIII.) 
 
 The principle of the common balance, (Fig. LVI1I.) 
 has already been described in Natural Philosophy. It 
 remains for us to say a few words on the construction of 
 beams, or portable balances (Figs. LVI and LVII.) These 
 are insturments of great utility to the practical chemist, 
 and serve either for the determination of the specific gravi- 
 ty of substances, or to show at once the proportion of their 
 chemical compositions. In the latter case they are called 
 per-cent balances. Fig. LVI represents Nicholson's porta- 
 ble balance. It consists of a hollow body, , made of silver 
 or tinned iron, to which is fastened a piece of thin wire, b, 
 which at its upper extremity supports a small plate or cup, 
 d. To the lower extremity of the body, a, is attached an- 
 other piece of wire,/, stronger than the one above, carry- 
 ing a metallic cone, g, the lower point of which is filled out 
 with lead to give the apparatus a perpendicular direction, 
 
34 CHEMICAL APPARATUS. 
 
 when immersed in water. The weight of the whole must 
 be less than the water which it displaces, in order that it 
 may swim, (see Natural Philosophy, Hydrostatics,) and 
 be able to bear a small additional weight upon the cup, d, 
 before it sinks to the point, e, marked upon the upper wire. 
 The use of this apparatus in determining the specific 
 gravities of bodies is exceedingly simple. When the body 
 whose specific gravity is to be determined is a liquid, then 
 immerse the apparatus first in water, and then in the pro- 
 posed liquid ; placing in each case as many weights in the 
 cup, d, as is necessary to make it sink to the point, e. The 
 weight of the apparatus added to the weight placed in the 
 cup, d, will in each case give the weight of equal volumes 
 of both liquids, which, divided by one another, will give 
 the specific gravity of the liquid in question. To give an 
 EXAMPLE : Suppose the weight of the apparatus is 180 
 grains, and the weight required to make it sink in water 
 to the point, e, equal to 42 grains more. Suppose 80 grains 
 were necessary to make it sink to the point, e, in the oth- 
 er fluid ; then 42 added to 180 gives 222 grains for the 
 weight of the water ; and 80 added to 180 gives 260 grains 
 for the weight of the liquid ; and dividing 260 by 222, we 
 obtain 1, 17 for the specific gravity of the liquid. 
 
 If the body whose specific gravity we wish to 
 know is a solid, then place it in the cup, d, and add to 
 it as many weights as will sink the apparatus to the point, 
 e. By this means you find the absolute weight of the body. 
 For if the apparatus requires 42 grains of itself to sink to 
 the point e, and now that the body is in the cup, d, it re- 
 quires but 30 grains, the body itself must evidently weigh 
 12 grains. Hence the absolute weight of a body is found 
 by subtracting the weights added to it when in the cup, d t 
 from the weight which is required to sink the balance alone 
 to the point e. Remove the body now from the cup, d } to the 
 hollow cone, g% and the apparatus will immediately rise ; for 
 it will lose as much of its weight as the water weighs, which 
 the body now displaces. (Natural Philosophy.) Adding 
 therefore as many weights to the cup, d } as will make the 
 apparatus again sink to the point e, we determine the abso- 
 lute weight of an equal volume of water ; and dividing the 
 absolute weight of the body by the weight of an equal vol- 
 
CHEMICHL APPARATUS. 35 
 
 ume of water, we obtain its specific gravity. To give an 
 EXAMPLE : Suppose the balance requires of itself 42 
 grains to sink to the point e, but when the body is in the cup 
 it requires but 12 grains ; and if the body be now removed 
 from the cup, d, to the cone, g, 5 further grains are necessa- 
 ry to sink the apparatus to the point, e; required the spe- 
 cific gravity of the body 1 Ans. By the first supposition 
 it is evident that the body must weigh 30 grains ; and by 
 the second it is plain that an equal volume of water weighs 
 5 grains ; hence 30 divided by 5, equal to 6, is the specific 
 gravity of the body. (See Natural Philosophy, Chap. IV.) 
 The per cent balance Fig. LVII, is an instrument by 
 which the degree of mixture of two liquids, or of a liquid 
 with a solid substance is ascertained. It consists of a hol- 
 low body, , made of silver or tinned iron, bearing upon 
 its upper extremity a scale, a b, and on its lower end some 
 heavy substance to give the apparatus a perpendicular di- 
 rection when immersed in the liquid. The scale is gen- 
 erally divided into 100 degrees, each degree marking the 
 existence of 1 portion of one liquid in another, or of a solid 
 substance in a liquid. But such a scale will only serve for 
 one particular kind of mixture, and must be altered or 
 changed if applied to another. Such are the beer, bran- 
 dy or spirit scales, which by the degree of their immersion 
 in these respective liquids, show the quantity of alcohol 
 contained in them. The deeper they immerse, the less 
 water, and consequently the more alcohol is contained in 
 these liquids ; alcohol being specifically lighter than water. 
 (See Natural Philosophy, Chap. IV.) But the scale used 
 for brandy would not answer for beer or wine, and vice 
 versa. 
 
 Tc. Lutes. 
 
 XXVII. These are employed to join together the parts 
 of vessels which are used in distillation, to prevent the es- 
 cape of vapors. A mixture of China clay with a solu- 
 tion of borax will do for metallic vessels. When the liquid 
 which is to be distilled is not corrosive, slips of bladder or 
 paper spread with gum arabic or flour-paste will answer 
 the purpose; 8 parts of yellow wax mixed with one part 
 of turpentine oil, forms a very good resinous lute. 
 
36 CHEMICAL COMPOSITION OF BODIES. 
 
 TV. CHEMICAL COMPOSITION OF BODIES. 
 
 XXVIII. All bodies in nature are either animate or in- 
 animate. The former, to which belong the plants and an- 
 imals, are composed of a variety of exceedingly delicate 
 vessels, filled with liquids, of which each has a particular 
 office, and the assemblage of which forms what is called 
 their organization. Hence it is also customary to call 
 plants and animals organized or organic bodies, in opposi- 
 tion to dead or inanimate substances, which being merely 
 composed of particles kept together by the power of cohe- 
 sion, are said to be unorganized or inorganic. 
 
 XXIX. With regard to chemistry, all unorganized or 
 inorganic bodies are, 
 
 I. Either simple or compound ; that is, either as yet 
 not known to contain other ingredients, or composed of 
 two or more heterogeneous substances. 
 
 2- The compounds of unorganized bodies are most al- 
 ways formed by a binary combination (combinations of two 
 and two substances). Thus water is composed of two el- 
 ements, oxygen and hydrogen ; Saltpetre of two substan- 
 ces, nitric acid and alkali, of which each is again a com- 
 pound of two other substances : (nitric acid is a compound 
 of nitrogen and oxygen, and alkali a compound of Potas- 
 sium and oxygen.) See introduction, VII. 
 
 3. The compounds of unorganized bodies can, in most 
 cases, be produced by the combination of their elements. 
 Thus, water may be produced, as we shall see hereafter, 
 by combining oxygen and hydrogen in the proper propor- 
 tions; saltpetre may be produced by a combination of 
 nitric acid and alkali, &c. 
 
 Organized bodies, on the contrary, are 
 
 1. Generally composed of more than two elements. 
 
 2. They cannot be produced by art, through a combi- 
 nation of their chemical ingredients ; because they all con- 
 tain a certain vivifying principle, totally unknown to us ; 
 and which will probably forever escape all our anatomical 
 and chemical researches. 
 
 XXX. A vast number of organized and unorgan- 
 
CHEMICAL COMPOSITION OF BODIES. 
 
 37 
 
 ized bodies have been subjected to chemical analysis, and, 
 by means of art, been decomposed into their ingredients ; 
 but there are fiftyfour substances, which, thus far, have 
 resisted all attempts to decompose them, and, on that 
 account, are called elements. Of these, 4 are gaseous or 
 aeriform bodies ; 9 are solid, non-metallic substances ; 
 and 41 are metals. We shall here annex their names, 
 and propose to treat separately of the properties and com- 
 binations of each in the course of this book. 
 
 NOMENCLATURE OF ELEMENTS. 
 
 a. Gaseous Elements. 
 
 1. Oxygen, 3. Nitrogen, 
 
 2. Hydrogen, 4. Chlorine. 
 
 b. Solid Substances. 
 
 5. Carbon, 
 
 10. Iodine, 
 
 6. Sulphur, 
 
 1L Bromine, 
 
 7. Selenium, 
 
 12. Silicon, 
 
 8. Phosphorus, 
 
 13. Fluorine. 
 
 9. Boron, 
 
 
 
 c. Metals. 
 
 14. Potassium, 
 
 32. Iridium, 
 
 15. Sodium, 
 
 33. Osmium, 
 
 16. Lithium, 
 
 34. Nickel, 
 
 17. Calcium, 
 
 35. Iron, 
 
 18. Barium, 
 
 36. Lead, 
 
 19. Strontium, 
 
 37. Tin, 
 
 20. Magnesium, 
 
 38. Copper, 
 
 21. Glacinum,or Berillium, 39. Zinc, 
 
 22. Yttrium, 
 
 40. Bismuth, 
 
 23. Allumium, 
 
 "41. Cobalt, 
 
 24. Zirconium, 
 
 42. Antimony, 
 
 25. Thorium, 
 
 43. Arsenic, 
 
 26. Mercury, 
 
 44. Manganese, 
 
 27. Silver, 
 
 45. Tellurium, 
 
 28. Gold, 
 
 46. Titanium, 
 
 29. Platinum, 
 
 47. Cerium, 
 
 30. Palladium, 
 
 48. Uranium, 
 
 31. Rhodium, 
 
 49. Columbium, 
 
 4 
 
 
38 CHEMICAL COMPOSITION OF BODIES. 
 
 50. Tungsten, (Wolfram,) 53. Molybdenum, 
 
 51. Cadmium, 54. Vanadium. 
 
 52. Chromium, 
 
 And of these 54 elements the whole infinite variety of 
 bodies is composed ! ! 
 
 XXXI. The various chemical compositions arising from 
 the combination of these elements may again be arranged 
 under six different heads : 
 
 1. Oxides. This name is applied to all combinations 
 of oxygen with another element. Thus, the combination 
 of oxygen with iron is called oxide of iron ; that of oxygen 
 with manganese, oxide of manganese, &c. 
 
 2. Adds. These are combinations of certain substan- 
 ces with acidifying (acid-producing) principles, common- 
 ly oxygen or hydrogen, and distinguish themselves by the 
 following properties : 
 
 a. They have generally (not always) a sour taste. 
 
 b. Most of them are soluble in water ; and change blue 
 vegetable colors into red. 
 
 c. They are all negatively electric; (Natural Philoso- 
 phy, Chap. IX.) that zs, they adhere to the positive or zinc 
 pole of the voltaic pile. (To understand this more com- 
 pletely see the remark on the following page.) 
 
 d. Combined with solid substances they form salts, or 
 at least substances which bear a great resemblance to salts. 
 The last mentioned properties are, by modern chemists, 
 considered the most characterizing and essential qualities 
 of acids. 
 
 3. Bases. To this class belong all substances remark- 
 able for the following two properties : 
 
 a. When combined with acids they form salts ; and 
 
 b. When separated from a combination with an acid by 
 the action of a voltaic battery, they adhere to the negative 
 pole. They are consequently positively electric. 
 
 * Not all acids have a sour taste ; neither do all acids necessarily 
 contain oxygen, as it was once believed. Prussic acid, for instance, 
 has a bitter taste, and contains no oxygen in its composition. 
 
CHEMICAL COMPOSITION OF BODIES 39 
 
 The learner ought to direct his attention particularly to the 
 distinguishing characteristic between acids and salts ; viz. 
 that the acids are negatively, and the bases positively electric. 
 
 4. Salts. So are termed the almost innumerable com- 
 binations of the bases with the acids. 
 
 5. Sulphides and Chlorides. These are combinations 
 of sulphur or chlorine with an element, commonly a metal. 
 
 6. Alloys of Metals. These are combinations of one 
 metal with another. The combinations of quicksilver 
 with other metals have received the special name of Amal- 
 gams. 
 
 The theory of Galvanic electricity, as well as that of the 
 voltaic pile or battery, has already been given in the ninth 
 chapter of Natural Philosophy. It has there been stated, that 
 the most important experiments which can be made with the 
 galvanic battery belong to chemistry. This is so far true that 
 it may well be said that the theory of Galvanic electricity has 
 changed the face of the science of Chemistry. Its influence 
 upon the chemical decomposition of bodies stands unrivalled 
 by any other agent in nature, and is truly universal. There is 
 hardly a substance in nature, upon which galvanic electricity 
 does not more or less exercise its influence ; and by its agency 
 the most difficult chemical decompositions have been effected 
 with comparative ease and facility. 
 
 EXAMPLE. The fixed alkalies, a class of bodies with whose 
 properties we shall become acquainted in the 3d chapter, were 
 believed to be elements, and resisted every attempt to decom- 
 pose thenr, until the brilliant discoveries of Davy and Berze- 
 lius, who dissolved them into their elements by means of pow- 
 erful Galvanic Batteries. Nor is this decomposing power of 
 Galvanic electricity confined to a few chemical compounds ; 
 for nearly all the acids, and the class of bodies we have dis- 
 tinguished by the name of salts, yield their elements when ex- 
 posed to the action of this universal agent. It is on this ac- 
 count, Galvanic Electricity has become a criterion (and indeed, 
 as we have said before, the best criterion we have) of the 
 basic or acid nature of a chemical substance. For whenever 
 a salt is decomposed into its two principal constituents, the 
 acid and the basis, the acid adheres invariably to the positive, 
 and the basis to the negative pole of the galvanic battery. Now 
 as the positive or zinc pole of the battery attracts only nega- 
 tive electric bodies, (see Natural Philosophy, Chap. IX.) and 
 the negative or copper pole attracts positively electric sub- 
 
40 
 
 CHEMICAL COMPOSITION OF BODIES. 
 
 stances, we conclude that all acids are in reference to the 
 class of bodies which are called bases, negatively, and all 
 bases in reference to the acids, positively electric substances. 
 But it does not follow from this that a basis cannot of itself be 
 attracted by either of the two poles, or that an acid cannot be 
 composed of two elements, which evince again opposite elec- 
 tricities to each other. This as we shall soon see, occurs 
 frequently enough ; but it is sufficient for us at present, to 
 understand the difference between an acid and a basis, as we 
 shall revert to this subject again in the fourth Chapter. 
 
 We shall now describe the manner in which the combina- 
 tions of the almost innumerable class of bodies which are 
 characterized by the names of salts and acids, is effected by 
 galvanic electricity. (See Natural Philosophy, Chapter IX.) 
 Fig. LIX. 
 
 If the trough apparatus (Fig. LIX.) is used, then the cells, 
 A, are filled with water, which contains in solution a quan- 
 tity of common salt, or which is mixed with a small portion 
 of muriatic or sulphuric acid. The plates, B, which are fit- 
 ted to these cells and connected by a slip of wood, are then 
 let down into the cells, and the two conducting wires, Z 
 and C, (of which Z is connected with the positive, or zinc 
 pole, and C with the negative or copper pole) are brought 
 in contact with the substance, S, which is to be submitted to 
 the agency of the battery. Now if this happens to be a salt, 
 it has been found that the acid of which it is composed ad- 
 
CHEMICAL COMPOSITION OP BODIES. 41 
 
 heres invariably to the positive or zinc pole, Z, and the basis 
 to the negative, or copper pole, C, of the battery. 
 
 A very convenient apparatus of this kind, which may be at 
 pleasure increased or diminished, is Count Stadion's Couronne 
 Fig. LX. 
 
 des Tasses, or cup-battery. It consists of a number of cups 
 of glass or wedgewood, (see Fig. LX.) In each cup is placed 
 a plate of zinc, and another of copper, in such a manner that 
 the metals do not touch each other in the cups ; but are without 
 connected with each other by slips of metal. The same order 
 of plates zinc, copper, zinc, copper, &c, is of course preserved 
 throughout the apparatus. When the cups are filled with a 
 solution of salt or muriatic acid, then the effect is the same as 
 that produced by the trough-battery. It is easily perceived 
 that the strength of such an apparatus may be increased or di- 
 minished by employing a greater or smaller number of cups. 
 
 To account for the chemical decomposition of bodies 
 by Galvanic Electricity, several ingenious theories have 
 been invented, among which that of Sir Humphrey Davy 
 deserves decidedly the preference. He supposes the ele- 
 ments of all chemical compounds to be originally possess- 
 ed of opposite electricities. These opposite electricities 
 are, by the chemical affinity which these elements have for 
 one another, kept in a perfect state of equilibrium. But 
 when such a compound is exposed to the agency of a gal- 
 vanic battery, then the attractive and repulsive force of the 
 two opposite poles, effect a separation of its elements ; the 
 negatively electric element flies to the positive or zinc pole, 
 and the positively electric ingredient, to the negative pole 
 of the battery. Those substances which adhere to the neg- 
 ative pole are then said to be positively electric ; and 
 those which adhere to the positive pole of the battery are 
 called negatively electric bodies. Thus according to what 
 4* 
 
42 RECAPITULATION. 
 
 we have said all acids are, in reference to those substances 
 which we call bases, negatively electric ; and all bases 
 are, in reference to the acids, positively electric substances. 
 This theory, although there are several objections to it, 
 is strongly corroborated by some very prominent phenom- 
 ena, which accompany the decomposition of salts by gal- 
 vanic Electricity ; and of which we shall have an oppor- 
 tunity to speak hereafter when treating of salts. 
 
 RECAPITULATION. 
 
 [The preceding Introduction, contains the outlines of Gene- 
 ral Chemistry. It will therefore be well for the teacher to go 
 over it a number of times until he is perfectly satisfied that 
 his pupils have understood the definition of chemistry, andean 
 give a tolerably good account of the laws of affinity and chem- 
 ical action. Not until then ought they to commence the study 
 of the first chapter.] 
 
 I. QUESTIONS ON DEFINITIONS. 
 
 [I.] Into how many classes are all natural sciences di- 
 vided 1 What are these ? 
 
 [II.] What is the object of Natural History 1 Which 
 are the three great branches of Natural History 1 
 
 [III.] What is the object of Natural Philosophy ? Into 
 what two branches has Natural Philosophy been divided ? 
 How do you define Chemistry 1 
 
 [IV.] What do you call the peculiar kind of attraction 
 which is only manifest in contact, and which is the cause 
 of a change in the properties of bodies ? 
 
 Give an example. 
 
 [V.] In how many different ways does the chemical 
 affinity which one body has for another manifest itself ? 
 What are these two ways 1 What is the first of these 
 processes called 1 What the second ? 
 
 Give an example of chemical composition or synthesis. 
 Give an example of chemical analysis. 
 
RECAPITULATION. 43 
 
 What is the difference between mechanical and chemical 
 separation ? Give instances of mechanical and chemical di- 
 vision. 
 
 [VF.] What are the parts obtained by a chemical sep- 
 aration or analysis called? What is the body called from 
 which they are derived ? 
 
 Give an example. 
 
 [VII.] When do you call a body composed of nearer 
 and more remote ingredients 1 
 
 Give an example. 
 
 Which, in your example are the nearer, and which the 
 more remote ingredients ? 
 
 [VIII.] What are those substances called which are 
 not, as yet, decomposed by any means in our power 1 Does 
 it follow from this that all substances which are now con- 
 sidered as elements are really incapable of analysis ? 
 
 What then does the word element express in chemistry ? 
 
 II. QUESTIONS ON CHEMICAL ACTION. 
 
 [IX.] What kind of attraction must be considered as 
 the principal cause of all chemical phenomena? What 
 changes does chemical affinity produce on bodies which 
 are subjected to its action ? 
 
 [In the answerto this question the pupil ought only to enu- 
 merate the three principal changes, a, &, c, printed in italics.] 
 
 Give examples of changes produced in the temperature ; 
 of changes produced in the physical properties of bodies ; 
 and of changes produced in aggregate form of bodies. 
 
 [X.] Does chemical action ever take place without a 
 change of temperature ? What important fact do you 
 know respecting it ? Does heat generally favor or coun- 
 teract chemical affinity 1 
 
 Give examples. 
 
 [XI.] What is the greatest obstacle to chemical affin- 
 ity 1 Why do bodies combine readiest with each other, 
 when one or the other has been reduced to the fluid state ? 
 Why does heat increase the action of chemical affinity? 
 
44 RECAPITULATION. 
 
 What general inference has been drawn from this ? Is 
 this rule without exception ? 
 
 What would take place if there were no cohesive attraction 
 to counteract the chemical affinities of bodies ? How must 
 chemical affinity and cohesive attraction be considered in ref- 
 erence to each other? 
 
 [XII.] When are two bodies said to be neutralized ? 
 
 Give examples of neutralization. 
 
 In what state are potash and sulphuric acid contained in the 
 salt which is formed by their combination ? What is neces- 
 sary in order to effect a complete neutralization ? 
 
 [XIII.] What are those combinations called, in which 
 the ingredients still preserve a portion of their original 
 properties ? 
 
 Give an example of such a combination. 
 
 [XIV.] To what must we have recourse in order to 
 decompose a chemical compound into its constituent parts ? 
 What is that kind of chemical attraction called, in con- 
 sequence of which a body quits a combination already ex- 
 isting, for the sake of forming a new one ? Why is this 
 attraction called elective affinity 1 
 
 Give an example of the action of elective affinity. (Ex- 
 plain the figure, page 7.) 
 
 What substance, in your example, shows an elective affinity 
 for potash ? Why ? 
 
 [XV.] What is the product of the combination of a solid 
 body with a flujd called ? Does the affinity between a solid 
 and a liquid substance continue forever, or is it limited to 
 a certain point? How is that point called, beyond which 
 the solving power of the liquid ceases to operate upon the 
 solid 1 What is the solution itself said to be, when arrived 
 at this point 1 
 
 Give an example. 
 
 [XVI.] Upon what three things does the saturation of 
 liquids principally depend ? Is there no exception to the 
 general rule, that heat increases the solving power of 
 liquids'? 
 
 Give examples. 
 
RECAPITULATION. 45 
 
 [XVII.] What do some compounds of two substances 
 require for their decomposition ? When is this the case 1 
 What do you call this kind of affinity 1 
 
 Give an example. (Explain the table on page 9.) 
 
 To what do some philosophers ascribe these phenomena ? 
 Why? 
 
 What substance in your example (page 9) exercises a pre- 
 disposing affinity upon oxygen ? Why ? By what means 
 does the acid predispose the oxygen for a combination with 
 the zinc ? 
 
 [XVIII.] What does frequently happen when two 
 compounds are brought together in a state of solution ? 
 What is this compound action said to be caused by ? 
 Give an example. (Explain the table on page 10.) 
 Which substance, in your example, does the acetic acid 
 elect in preference to the lead, with which it was combined ? 
 Which substance does the sulphuric acid elect in preference 
 to the zinc ? And why is this action called double elective 
 affinity ? 
 
 [XIX.] In what other manner do bodies combine, be- 
 sides forming mixtures, or dissolving others to saturation ? 
 What sort of compound do we always obtain from a com- 
 bination in fixed proportions ? 
 
 Give an example. 
 
 Do bodies always combine with each other in only one 
 fixed proportion 1 Give an example where one substance 
 combines .with another in several fixed proportions ? 
 
 Have similar fixed substances been discovered in the 
 combinations of other bodies ? And what has been ob- 
 served in reference to these combinations 1 What general 
 principle are we enabled to lay down, from these observa- 
 tions ? 
 
 If the remainder of this section should be found too diffi- 
 cult for the beginner, it may be omitted until reviewing the 
 first four chapters of the book. But it would be better for 
 him if he could explain the example on page 12. If he has 
 understood it well, let him take the substance B, in reference 
 to A, C, D, E, and F. and determine from that the relation of 
 A to C, to D, E, and F, &c. The better he understands this 
 example, the better will he be able to comprehend the one 
 which is taken from nature, and which consists of larger pro- 
 portions. 
 
46 RECAPITULATION. 
 
 Let the pupils now explain the table on page 13. The 
 teacher may also let them copy that table, and then ask the 
 following questions : Ques. Why are 37 weights of mu- 
 riatic acid said to be an equivalent to 40 weights of sulphuric 
 acid ? Why are 40 weights of sulphuric acid an equivalent to 
 54 of nitric acid, or to 28 of phosphoric acid ? Why are 28 
 weights of lime equivalent to 48 weights of Potass, or to 32 
 of soda ? 
 
 What is the smallest number of weights of one sub- 
 stance called which combines to saturation with all other 
 substances for which it has a strong chemical affinity ? 
 By what means is the chemical equivalent of a compound 
 substance found, when the chemical equivalents of its 
 elements are known 1 
 
 Explain example I. Explain example II. Explain 
 example III. 
 
 III. QUESTIONS ON CHEMICAL APPARATUS. 
 
 [XX. J a. What instruments are principally used for 
 dividing bodies ? 
 
 b. What instruments are used for separating liquids 
 from solids. Explain the separatory funnel, (Fig. XVII, 
 page 19) and its operation. 
 
 c. What apparatus is used for the liquefaction of solids. 
 
 [XXI ] d. What apparatus is used for evaporation and 
 crystallization 1 Why must the form of evaporating dish- 
 es be flat 1 What is the process of evaporation called, 
 when it takes place under the influence of heat 1 What 
 apparatus is used for this purpose 1 
 
 [XXII.] e. What is the most common apparatus used 
 for collecting the volatile portion of a body which escapes 
 through the process of evaporation ? Describe Fig. XXV. 
 Describe the common still, (Fig. XXVI.) What is the 
 name of the instrument most commonly employed in distil- 
 lation ? Explain Figs. XX VII and XXVIII. What other 
 apparatus answers most purposes for which retorts are used ? 
 
 f. In what consists the apparatus for heating chemical 
 substances 1 On what principle are both, the portable air- 
 
RECAPITULATION. 47 
 
 furnace with crucible stands, and the fixed wind-furnace 
 constructed ? What is the construction of the common 
 lamp? What is the difference between a common lamp 
 and a spirit lamp 1 In what consists the principal advan- 
 tage of an Argand's lamp over a common lamp ? For 
 what purpose is the flame of an Argand's lamp covered 
 with a cylindrical open glass ? 
 
 How is Guiton's lamp furnace constructed 1 (Explain 
 Fig. XXXVI, page 25.) 
 
 What is the name of the instrument which is used for 
 producing a very intense heat with a common oil or spirit 
 lamp? Of what does it consist? Explain its operation 
 and the manner in which it is used. 
 
 What is the difference between Gahn's blow-pipe and 
 the common blow-pipe ? Explain Fig. XXXVIII. In 
 what does the advantage of this apparatus consist? 
 
 What other still more convenient contrivance is there, 
 than either the common or Gahn's blow-pipe. Explain 
 Fig. XXXIX. 
 
 [XXIII. ] How many different kinds of presses are 
 used for extracting liquids from solid substances. Explain 
 Fig. XL. Explain Fig. XLI. 
 
 What apparatus is frequently used when a solid sub- 
 stance is to be dissolved in a liquid ? Describe Fig. 
 XLII. 
 
 How is Brahma's Hydraulic press constructed ? Ex- 
 plain Fig. XL1II. 
 
 [XXIV.] What apparatus is used for collecting gases ? 
 Describe Fig. XLIV. What other apparatus is used for 
 collecting gases? Explain Fig. XLV. What applica- 
 tion is made of Priestley's bell glass ? Explain Fig. 
 XLVI. 
 
 [XXV.] What other apparatus is used for various other 
 chemical purposes ? Explain Nicholson's portable balance 
 Fig LVII. How is the specific gravity of a liquid deter- 
 mined by means of Nicholson's portable balance? (Ex- 
 plain the example, page 34.) How is Nicholson's balance 
 to be used when the body whose specific gravity we wish to 
 determine is a solid ? (Explain the example on page 35.) 
 
48 RECAPITULATION. 
 
 What sort of an instrument is the per-cent balance ? 
 How is it constructed 1 (explain Fig. LVII.) Can the 
 scale which is used for one mixture of liquids be employ- 
 ed also for another ? 
 
 [XXVI.] For what purpose are lutes employed ? 
 What kind of lute will answer for metallic vessels ? What 
 sort of lute will answer for liquids which are not corrosive ? 
 What composition makes a good resinous lute ? 
 
 IV. QUESTIONS ON THE CHEMICAL COMPOSITION OF 
 BODIES. 
 
 [XXVII.] To what class of bodies belong plants and 
 animals ? Of what are plants and animals composed ? 
 What are all inanimate substances merely composed of? 
 
 [XXVIII.] What characterizing properties have all 
 inanimate bodies in reference to chemistry 1 (The answer 
 to this question consists in the recitation of the three heads, 
 1, 2, 3, printed in italics.) Give an example of binary 
 combinations of bodies. What characteristics, on the 
 contrary, distinguish all organized bodies ? How many 
 different substances are there, which have thus far resisted 
 all attempts to decompose them ? What are they there- 
 fore called ? How many of these elements are gaseous ? 
 How many are non-metallic solid substances ? How many 
 are metals 1 
 
 If the teacher thinks fit, the pupils might now commit their 
 namevS to memory, or they may also omit this, until the review- 
 ing of the book. 
 
 [XXIX.] Under how many different heads may the va- 
 rious chemical compositions, arising from the combination 
 of these elements be arranged 1 What are they ? (The 
 answer to this question consists in the enumeration of the 
 six heads, Oxides, Acids, Bases, &>c. 
 
 What substances are called oxides? 
 
 Give examples. 
 
 What substances are called acids ? What are the char- 
 acterizing properties of the Acids ? 
 
 By what properties are those bodies distinguished which 
 are called Bases 1 
 
RECAPITULATION. 49 
 
 What are salts? 
 
 What are sulphides and chlorides ? 
 
 What do you understand by alloys of metals I 
 
 [Upon the remainder of this section the teacher need 
 ask but a few questions, as the same subject occurs again 
 in the 4th chapter.] 
 
 What becomes of all salts when exposed to the action 
 of Galvanic Electricity ? Why is galvanic electricity the 
 best criterion of a salt or an acid 1 Describe the manner 
 in which salts are decomposed by galvanic electricity ? 
 (Explain Fig. LIX.) 
 
 Of what does Count Stadion's Cup-battery (Couronne 
 des Tasses) consist? (Explain Fig. LX.) 
 
 What is Sir Humphrey Davy's theory with regard to the 
 electrical phenomena exhibited by all chemical coin- 
 pounds? What, according to this theory, are all those 
 substances called which adhere to the negative pole of the 
 galvanic pile ? What, those which adhere to the positive 
 pole? 
 
 What are all acids in reference to that class of bodies, 
 which are called bases ? What, all bases with regard to 
 those substances called acids ? 
 
CHAPTER I. 
 
 OP THE PROPERTIES AND COMBINATIONS OF THE FOUR 
 
 GASEOUS ELEMENTS, OXYGEN, HYDROGEN, 
 
 NITROGEN, AND CHLORINE. 
 
 A. Oxygen* 
 
 1. Properties of oxygen. By the name of oxygen 
 we distinguish a gas contained in our atmosphere, of which 
 it constitutes about 21 per cent ; (being the T 2 ^ part of 
 the whole atmosphere). It is also a component part of 
 water, forming nearly T 8 ^j of its whole weight. It is 
 colorless, a litile heavier than atmospheric air, and insol- 
 uble in water, and is destitute of either smell or taste. 
 Its presence is absolutely necessary to the continuance of 
 animal life ; but breathed in its pure state it is injurious, 
 because it affects the lungs. 
 
 2. Mode of obtaining ozyg'.-n. Oxygen is obtained 
 in a variety of ways, of which "it will suffice to mention 
 the following four : 
 
 1. From a substance called Chlorate of potash ; by 
 heating it in a retort and collecting the gas which is giv- 
 en off by means of the pneumatic tub. 
 Fig. LXI. 
 
 * From a Greek word, signify it g formation of acid. 
 
OXYGEN. 51 
 
 When the Chlorate of Potash is heated it fuses, and 
 gives off the oxygen in a very pure state, which is then, 
 through the pipe, conveyed to the receiver, in the manner 
 explained in the Introduction, page 30, Fig. XLIV. 
 
 2. From a substance called Red Oxide of quicksil- 
 ver. The process is nearly the same as that just de- 
 scribed. 
 
 3. From a substance called Black Oxide of manga- 
 nese. 
 
 4. From a variety of growing vegetables when exposed 
 to solar light, and from the green matter formed in stag- 
 nant pools, when immersed in water. This is an experi- 
 ment requiring no other apparatus than a tumbler filled 
 with water ; if at hand, Priestley's bell-glass is best adapt- 
 ed for it, having a contrivance at the neck, by which 
 means the gas may be introduced into another vessel or a 
 bladder. (See Fig. XLV, page 30.) 
 
 3. Combinations of oxygen. Oxygen combines with 
 nearly all simple and compound bodies. The process by 
 which this combination is effected is called the oxygena- 
 tion of bodies. This oxygen ation is sometimes accompani- 
 ed by the phenomenon of fire, (by light and heat) in which 
 case it is termed combustion. The products of the differ- 
 ent combinations of oxygen with other elements are either 
 oxides or acids ; according to the different proportions in 
 which the oxygen combines with them. 
 
 EXAMPLE. Carbon combined with oxygen gives 1 oxide 
 and 3 different acids. Sulphur combined with oxygen gives 4 
 different acids. Iron forms with it 2 different oxides, &c. 
 
 4. The different oxides and acids arising from the va- 
 rious combinations of oxygen with other substances, have 
 each received a particular name, indicative of the proportion 
 of oxygen contained in the combination. The oxides are 
 termed Protoxides, Deutoxidcs and Peroxides. The name 
 of Protoxide is given to the smallest quantity of oxygen com- 
 bined with another substance ; that of Deutoxide denotes 
 the next greater quantity of oxygen combined with it ; and 
 the name of Peroxide is applied to the greatest proportion 
 
52 OXY'GEN. 
 
 of oxygen which an oxide is capable of holding. With 
 regard to the acids, we are in the habit of distinguishing 
 them by iheir terminations, in ic or ous ; or by putting 
 the Greek preposition hypo (signifying under) before the 
 name of the acid. The name of the acid ending in ic in- 
 dicates the highest degree of oxygenation ; that termin- 
 ating in ous indicates the next lower degree ; a still lower 
 degree, if there be any, is expressed by the preposition 
 hypo. 
 
 EXAMPLE. The gas called nitrogen forms with oxgyen 
 three different acids, which, according to the degree of oxygen- 
 ation (the quantity of oxygen contained in their composition) 
 are called nitric acid ; nitrous acid, and hypo -nitrous acid. Ni- 
 tric acid indicates the highest degree of oxygenation ; nitrous 
 acid the next lower, and hypo-nitrous acid the lowest degree. 
 
 Theory of Combustion. 
 
 5. It has been said before ( 3) that the combination 
 of some bodies with oxygen is accompanied by fire in 
 which case it is called the combustion, or burning of bodies. 
 The combustion or burning of bodies, therefore consists in 
 their sudden combination with oxygen.* Every body capa- 
 ble of such a combination is called a combustible sub- 
 stance. 
 
 Phlogiston of the ancients. The ancient chemists ascribed 
 the process of combustion, or the phenomenon of fire, to a par- 
 ticular substance which they called phlogiston. But this the- 
 ory has long ago been exploded ; and it is now generally taken 
 as an established fact that this phenomenon is produced, as we 
 have said before, by the sudden union of oxygen with a com- 
 bustible body. 
 
 6. Degree of temperature necessary for combustion. 
 There are bodies which combine with oxygen to combus- 
 tion without being previously heated (as is, for instance, 
 the case with a substance called sulphuretted hydrogen) ; 
 most bodies, however, require for this purpose a certain high 
 degree of temperature. 
 
 * We su.ill se.3 hero.ifter that the gas termed chlorine is in a cer- 
 tain measure capable of producing similar phenomena. 
 
OXYGEN. 53 
 
 EXAMPLE. Sulphur, wood, coal, phosphorus, &c, must first 
 be heated to a certain degree of temperature before they ex- 
 hibit the phenomenon of fire. But when these bodies are 
 once heated, they generally give out sufficient heat to keep up 
 the degree of temperature necessary for their combustion. 
 
 Fig. LXII. Fig. LXHL 
 
 The chemical process of a burn- 
 ing candle (Fig. LXII,) or lamp, 
 (Fig. LXIII,) is this : The wick a, 
 is lighted by a piece of burning 
 paper or wood. By this means the 
 surrounding particles of fat or oil 
 are heated to the boiling point, 
 (Natural Philosophy, Chap. VI,) 
 and thereby decomposed as all an- 
 imal substances, into inflammable 
 gases. These combine with the 
 oxygen of the atmosphere and pro- 
 duce the phenomenon of light, 
 commonly called the^ame of the 
 candle. This flame gives out sufficient heat to keep the 
 degree of temperature necessary for the decomposition of 
 another portion of the fat or oil ; and so does this process 
 continue until the whole candle or oil is exhausted. 
 
 7. Light given out by the combustion of bodies, The 
 light which is given out by different substances during the 
 process of combustion is subject to variation in intensity 
 and color. 
 
 EXAMPLES. Phosphorus, zinc, and arsenic give out a white 
 light ; the flame of sulphur is blue ; that of selenium azure / 
 &c 
 
 The color of the flame does not only depend on the 
 burning substance, but also upon the degree of heat pro- 
 duced by its combustion. Most combustible bodies when 
 moderately heated burn with a yellow or blue flame ; par- 
 ticularly if there be no draft to supply the flame with fresh 
 quantities of oxygen. 
 
 8. Combustion in oxygen. All combustible bodies burn 
 in oxygen with increased splendor. 
 
 5* 
 
54 
 
 OXYGEN. 
 
 Fig. LXIV. 
 
 EXAMPLE. A small piece of wax 
 taper with its flame blown out, but 
 its snuff still red hot, when immers- 
 ed into a vessel filled with oxygen, 
 is instantly rekindled, and throws 
 out a most vivid light. -(See Fig. 
 LXIV.) 
 
 Fig. LXV. 
 
 A piece of sulphur or phosphorus, let 
 down into a jar filled with the same gas 
 will burn with indescribable brilliancy. 
 (See Fig. LXV.) 
 
 In order to perform these experiments a 
 common bottle or jar may be filled with 
 the gas by means of the pneumatic tub. 
 (Intr. page 30.) Through the cork of the 
 bottle a piece of wire may be made to pass, 
 containing at its lower end the body which is to be immersed. 
 (See the next figure.) 
 
 ANOTHER EXAMPLE. Iron, which only burns at very ele- 
 vated temperatures, needs but a red heat to burn in oxygen 
 gas with a light which is almost as dazzling and insufferable 
 to the eye as the sun itself. 
 
 Fig. LXV I. 
 
 A faint representation of it is 
 given in Fig. LXIV. A piece of 
 piano-wire spirally twisted, is in- 
 troduced air-tight through the 
 cork, a, of a bell-glass or receiv- 
 er filled with oxygen gas. To 
 the lower end of this wire is at- 
 tached a piece of thread, touch- 
 ed with sulphur or wax, to ignite 
 the wire in the first instance. 
 As the gas is a little heavier than 
 atmospheric air, its escape or 
 mixing with the atmosphere is 
 prevented by placing the receiv- 
 er in a basin filled with water. If we were to employ a com- 
 
OXYGEN. 55 
 
 mon jar for the same experiment, then the little globulse of 
 melted wire which drop during the process of combustion, 
 would melt the glass, or if the bottom of the vessel be thin, 
 fuse a hole through it, without breaking the glass. 
 
 Query What do all these examples prove, in reference to 
 the heat produced by the burning of substances in oxygen gas ? 
 Ans. These examples prove that the heat given out by the 
 combustion in oxygen gas is incomparably more intense than 
 that thrown out by combustion of the same substances in atmos- 
 pheric air. Query And what would become of our grates, 
 stoves, or iron forges, in short, of all the labors of the black- 
 smith, if our globe was surrounded by pure oxygen ? Ans. 
 Our grates and stoves would burn and melt the moment they 
 would get red hot ; and as to the labors of the black smith, 
 they would be entirely out of the question ; for in order to 
 shape iron, it must first be made red hot (it being exceedingly 
 hard in its natural state); and the moment it would get red 
 hot it would begin to burn and melt into balls. 
 
 9. If the whole product of combustion is weighed it is 
 always found to be heavier than the substance was before 
 the combustion. Thus, when a piece of wire is .burnt in 
 oxygen its weight is found to increase by 40 per cent, 
 that is, 100 grains of iron before the combustion, weigh 
 140 grains after it. The reason of this change in the 
 weightofiron, is because 40 grains of oxygen gas combined 
 with it during the combustion. A similar increase of 
 weight is noticed in all bodies which are burnt in oxygen 
 gas, and corresponding changes take place at every com- 
 bustion in atmospheric air. To this general rule it can- 
 not be objected that the ashes obtained from burning 
 wood, straw or other substances weigh generally much 
 less than these substances did before they were burned ; 
 because when these bodies are burnt in the open air, we do 
 not obtain the whole product of their combustion. A great 
 quantity of inflammable gas which is always given off dur- 
 ing their combustion, escapes through the chimney or in 
 the air. But when these are collected and their weight 
 added to that of the ashes, then the sum of these united 
 weights is always greater than that of the wood, straw, or 
 other substance before the combustion. 
 
 10. No combustion can take place without the pres- 
 
56 O X Y G E M . 
 
 etice of oxygen;* the process of combustion , therefore, can 
 only be continued as long as there is a sufficient quantity of 
 oxygen to support it. This follows immediately from what 
 we have said in 5. For if every combustion consists in 
 the combination of oxygen with a combustible substance, 
 it is self-evident that no such process can take place un- 
 less a sufficient quantity of oxygen is present. Moreover 
 we can mark the actual consumption of oxygen gas during 
 combustion by a very easy 
 
 Fig. LX VII. EXPERIMENT. Take a common 
 
 bell-glass or receiver, through the 
 cork of which introduce a piece of 
 bent wire, supporting at its lower end 
 a small lighted candle, a, and place 
 the whole over a basin of water. As 
 the candle is burning, the water of 
 the basin will rise in the receiver, so 
 that if a small scale be introduced 
 into the latter, the rising of the 
 water will indicate the quantity of 
 oxygen consumed. 
 Query What does the rising of the water in the receiver 
 prove ? Jlns. It proves that a portion of the gas in the re- 
 ceiver is consumed by the flame of the candle. Query Why ? 
 Ans. Because without such a consumption of the gas no 
 vacuum could be created in the receiver, into which the water 
 could be forced by the external air. 
 
 ANOTHER EXPERIMENT. Instead of oxygen, fill the re- 
 ceiver (in the last figure) only with common atmospheric 
 air. The burning of the candle, although less vivid, will 
 still consume a portion of air ; the water will still rise in the 
 receiver, although not so rapidly nor so high as when pure 
 oxygen is employed ; and the candle, after burning more and 
 more faint, will finally become extinguished. When the 
 quantity of air then remaining in the receiver is examinedj 
 it is found to have lost just y 2 ^ of its volume, which is ex- 
 actly the proportion in which oxygen is contained in atmos. 
 
 * We shall see in future that a few substances burn faintly in 
 chlorine ; but this can hardly be considered an exception to the 
 genera! rule. 
 
OXYGEN. 
 
 57 
 
 phericair. (See 1.) A burning candle now introduced 
 into this air is instantly extinguished ; small animals, birds, 
 frogs, &c, introduced into it speedily die ; in short, the 
 remainder of the air in the receiver is totally unfit either 
 to support combustion or the process of respiration of liv- 
 ing animals. 
 
 Query What does the slower burning of the candle in 
 common atmospheric air prove ? Jlns. It proves that the 
 vividness and splendor of the combustion depend on the great- 
 er or less quantity of oxygen which is consumed ? Ques. 
 But why does not the water rise as high in the receiver as 
 when pure oxygen is employed ? *Qns. Because the whole 
 quantity of air in the receiver is not consumed by the burning 
 of the candle ; but only that portion of it which is pure 
 oxygen. Ques. And why does the candle become extin- 
 guished, when -j- 2 ^ of the whole air originally contained in the 
 receiver are consumed? Jlns. Because the air which then 
 remains in the receiver is destitute of oxygen gas, and is on 
 that account incapable of supporting either combustion or res- 
 piration. Ques. What, therefore, is necessary in order 
 that a complete combustion of bodies shall take place in at- 
 mospheric air or oxygen ? Ans. It is necessary that a fresh 
 quantity of atmospheric air or oxygen should be supplied, 
 while the process of combustion is going on. 
 
 Fig. LXVIII. 
 
 ^^ ANOTHER EXAMPLE. A 
 
 burning candle introduced 
 into the receiver of an air- 
 ( pump (Fig. LXVIII,) burns 
 'slower and slower as the air 
 in the receiver becomes more 
 and more exhausted, (Natural 
 Philosophy, Chap. V,) until 
 finally it becomes wholly ex- 
 tinguished. A small animal 
 or a bird introduced instead' 
 of the candle will be thrown 
 into convulsions and expire. 
 Gunpowder, phosphorus, and 
 sulphur will cease to burn in 
 the vacuum. An improper 
 mixture of gases, in which 
 the oxygen is not contained in a sufficient proportion, produces 
 the same effect ; because it is then unfit to support the pro- 
 cess of combustion or respiration. 
 
58 OXYGEN. 
 
 What remarkable coincidence do you here observe 
 between the process of respiration and combustion ? Jins. 
 That oxygen is alike indispensable to the one and the oth- 
 er ; for whenever the process of combustion discontinues from 
 want of oxygen, that of respiration ceases also. Ques. 
 What mode, therefore, may be devised for finding out wheth- 
 er a certain mixture of gases is respirable or not? Jlns. 
 A burning candle may be introduced in it; when it continues 
 to burn the gas will be respirable ; when it is extinguished, or 
 burns but dimly, then the gas will not be fit for respiration. 
 
 This is a convenient way for trying the air in old wells 
 or in caverns, and cannot be too urgently recommended ; 
 many lives having been lost by omitting this caution. 
 
 11. The quantity of air or oxygen necessary for the 
 continuance of the process of combustion is supplied ei- 
 ther by a draft or by means of bellows. We know from 
 Natural Philosophy, (Chap. V,) that when a body is 
 burning, the heated air which surrounds it becomes spe- 
 cific, lighter, and ascends, while a fresh portion of exter- 
 nal air rushes in its place. This is called a draft. To 
 facilitate it we build fire-places and chimneys. The high- 
 er the chimney is, or the greater the difference between 
 the temperature of the air ascending in the chimney, and 
 that of the surrounding atmosphere, the greater is the 
 draft, and the better therefore will the fire burn. 
 
 Query Could you now devise a means for improving smok- 
 ing fire-places? */2ns. Yes. Smoking fire-places might be 
 improved by heightening the chimneys. Ques. Why? 
 Jlns. Because this would create a better draft, adding there- 
 by continually a new quantity of oxygen to the fire, and caus- 
 ing by that means a more perfect combustion. Query And 
 can you now explain the reason why an Argand's lamp (see 
 Fig. XXXV, page 24,) burns brighter when the glass is put on, 
 than without it ? Ans. Because the glass serves in this in- 
 stance as a sort of chimney, which increases the draft, 
 
 12. Extinguishing of Jire. Fire is extinguished, as 
 we have seen, by abstracting the oxygen from the burning 
 substance, or, which amounts to the same thing, by ex- 
 cluding the atmosphere from the burning substance. This 
 is effected by covering the combustible substance with an- 
 other substance, through which the oxygen of the atmos- 
 
OXYGEN. 59 
 
 phere cannot penetrate. For this purpose we commonly 
 employ water, merely because it is readiest procured ; but 
 then it is necessary to use a sufficient quantity to cover 
 the whole surface of the burning body. 
 
 Small quantities of water are of little or no use in confla- 
 grations ; but, on the contrary, rather contribute to increase 
 them ; because red hot coal, as we shall see hereafter, decom- 
 poses water into hydrogen and oxygen ; the latter of which 
 substances adds necessarily to the rapidity of the flames. 
 ( 7.) It is for this reason blacksmiths are in the habit of wet- 
 ting their coal before using it. 
 
 13. It has already been observed that some sub- 
 stances combined with oxygen without the phenomenon 
 of fire. This is the case when the combination takes 
 place very slowly. 
 
 It is in this manner many of the metals combine with oxy- 
 gen at the mean temperature of the atmosphere. Sodium, 
 potassium, iron, lead, tin and manganese are oxidized with- 
 out giving out any observable degree of heat or light. 
 Another substance, (which we shall become acquainted with 
 in the course of this work) termed nitric oxid, combines with 
 oxygen at the greatest cold ; while carbon unites with it at 
 a temperature exceeding (556 degrees Fahrenheit, without 
 the phenomenon of fire. 
 
 14. It remains for us to speak of the process of 
 desoxidation, which consists in separating the oxygen from 
 a body with which it is combined. It is effected two 
 ways : 
 
 1. By Jicat. This is the case with the oxides of the 
 precious metals, silver, gold, platinum, &c. 
 
 2. By the admixture of a third substance, commonly 
 potassium, for which oxygen has a great affinity. (See 
 Art. Potassium, Chap. III.) 
 
 The different combinations of oxygen with other substances 
 will be spoken of when treating of these substances. 
 
 75. Hydrogen. 
 
 15. When water is subjected to the action of Gal- 
 vanic Electricity, it is, as we have had occasion to remark 
 
60 
 
 HYDROGEN. 
 
 before, decomposed into two distinct gases, whose proper- 
 ties are in every respect directly opposite to each other. 
 These two gases are Hydrogen* and Oxygen. 
 Fig. LXIX. 
 
 The experiment may be made 
 either by means of a voltaic pile, 
 (Fig. LXIX,) or by a trough bat- 
 tery (see Fig. L1X, page 40). 
 When the voltaic pile is employ- 
 ed, the apparatus represented in 
 Fig. LXIX, in which the two poles 
 A, B, are introduced into a cylin- 
 drical tube filled with water, is 
 very convenient. 
 Fig. LXX. 
 
 When the trough-battery is used, 
 the two poles of the battery are 
 introduced into a bent glass tube, 
 shaped like a V,(see Fig. LXX.) 
 This tube is first filled with water 
 and then inverted and held over 
 a basin filled with the game liquid, 
 
 which in this case answers the purpose as a pneumatic 
 tub. The two gases, hydrogen and oxygen, inio which the 
 water is decomposed, rise in little bubbles to the top, but 
 are in both instances obtained in a state of mixture. 
 Fig. LXXL 
 
 To obviate this we make use of an ap- 
 paratus represented in Fig. LXXL The 
 two poles of the galvanic battery are 
 brought in contact with two brass knobs, 
 A and B, which by means of thin platina 
 wires melt into the glass, communicate 
 with the water in the bent tube. Each 
 of the extremities of the tube is fitted to a 
 small jar, closed with a stopper, and the 
 whole apparatus is filled with water. When the battery is 
 set in motion, the water in the tube becomes decomposed 
 
 * From a Gteek word, signifying formation of water. 
 
HYDROGEN. 61 
 
 and forms two distinct gases ; but by a fixed law of elec- 
 trical attraction (mentioned before in Intr. page 41,) one of 
 these gases, the hydrogen, always collects about the nega- 
 tive or copper pole, and on that account rises in little bub- 
 bles in the jar which is connected with that pole ; while 
 the oxygen follows the electric attraction of the positive or 
 zinc pole, and collects in the other jar. By tho aid of this 
 apparatus the two gases are obtained separately, and may 
 be examined for the sake of various chemical purposes. 
 What is most remarkable about this decomposition of wa- 
 ter is, that the volume of hydrogen gas thence obtained, is 
 always exactly double that of the oxygen, from which we 
 infer that in water two volumes of hydrogen are combined 
 with one volume of oxygen. But about this we shall soon 
 have occasion to say more. 
 
 Properties of Hydrogen Gas. 
 
 16. When hydrogen gas is examined in its pure 
 state (as obtained from the decomposition of water by gal- 
 vanic electricity), it is found to be destitute of color, taste, 
 or smell. It is much lighter than atmospheric air, only 
 one sixteenth as heavy as oxygen and indeed the light- 
 est ponderable substance in nature.* It is highly com- 
 bustible ( 5), and when ignited (kindled) by a burning 
 substance, or an electric spark, burns with a yellowish 
 flame and gives out great heat. It is unfit for respiration, 
 although it may be breathed for a short time with impuni- 
 ty. It is equally unfit to support the process of combus- 
 tion, although it is, itself, a highly combustible substance. 
 A burning substance immersed in it, is instantly extin- 
 guished. 
 
 * In speaking of the speci6c gravity of bodies, we always suppose 
 the pressure of the atmosphere equal to 30 inches of quicksilver, and 
 its temperature equal to 60 degrees of Fahrenheit's thermometer.- - 
 (See Grund's Natural Philosophy, article Gravity.) 
 
 6 
 
HYDROGEN. 
 
 Fig. LXXII. 
 
 EXPERIMENT. If a lighted candle or 
 wax taper is brought near the mouth of 
 a bottle or jar filled with hydrogen gas, 
 the gas will instantly ignite at the mouth 
 of the bottle ; but the taper itself, when 
 deeper immersed, will be extinguished. 
 When the taper is drawn out, it will again 
 be ignited by the burning hydrogen at 
 the mouth of the bottle. This experi- 
 ment may be repeated a number of times, 
 until the gas is entirely exhausted. 
 
 Query What does the inflammation 
 (ignition) of the gas at the mouth of the 
 bottle prove ? Jlns. It proves that hydrogen is a highly com- 
 bustible substance. Query And what does the extinguish- 
 ing of the candle when immersed in hydrogen, show ? Ans. 
 It shows that although hydrogen is, itself, a highly inflamma- 
 ble gas, it is not capable to support the combustion of other 
 substances. 
 
 Fig. LXXIH. 
 
 ANOTHER EXPKRIMENT, which shows that the 
 specific gravity of hydrogen is much less than 
 that of atmospheric air, may be performed by 
 lAfilling two common beer or wine glasses (Fig. 
 LXXIII,) with this gas, and placing them, one 
 with its open mouth up, and the other down. 
 In a few minutes the gas will have entirely es- 
 caped from the glass B, which is placed with 
 its mouth up but it will still be found in the 
 one, A, which has its mouth turned downwards. 
 This may be easily ascertained by applying the flame of a can- 
 dle to the mouth of each glass. The hydrogen contained in 
 the glass, A, will burn ; but in B there will be nothing but at- 
 mospheric air, which of course will not ignite. 
 
 Query Why has the gas escaped from the glass which 
 has its'mouth up? Jlns. Because hydrogen being much 
 lighter than atmospheric air, would naturally ascend as a 
 piece of wood does, when placed under water. Query But 
 why does the gas remain in the glass with its mouth down ? 
 Ans. Because a vessel filled with hydrogen, having its 
 mouth turned downwards, may be considered as closed ; for 
 the escape of the gas is prevented from above, and the pressure 
 of the heavier atmosphere does not permit it to descend below. 
 
HYDROGEN. 
 
 63 
 
 Fig. LXXIV. 
 
 Query In what manner then can you transfer 
 hydrogen gas from one vessel to another ? Ans. 
 It is only necessary to place the mouth of an open 
 vessel or receiver, B, (Fig. LXXIV,) over the open 
 neck or mouth of another vessel or jar, A, rilled 
 with the gas. The gas will, on account of its levity, 
 escape thrrough the neck of the vessel, A (through 
 which, for convenience sake, an open tube may be 
 made to pass), and ascend in the receiver B, from 
 which it will expel the atmospheric air. 
 
 ANOTHER EXPERIMENT, which shows the levity of hydrogen 
 gas, and at the same time enables us to find its specific grav- 
 ity is the following. 
 
 LXXV. 
 
 Take an open jar or phial, C, 
 which attach to one scale of a 
 common balance with its mouth 
 downwards, and set the whole 
 apparatus in equilibrium by add- 
 ing as much weight to the scale 
 B, s is necessary for that pur- 
 pose. Conduct hydrogen from a 
 Florence flask, F, into the jar. 
 In proportion as the hydrogen 
 ascends through the pipe, P, 
 and expels the atmospheric air 
 from C, the scale B will sink ; 
 and by marking the weight which 
 it is finally necessary to place 
 upon A, in order to restore the equilibrium, we determine the 
 difference between the weight of atmospheric air previously 
 contained in it, and that of an equal volume of hydrogen gas. 
 This will enable us to find the specific gravity of hydro- 
 gen. For when the weight of the atmospheric air in the 
 jar A is known, (which may be easily obtained by finding 
 what the jar weighs when the air is exhausted from it) it 
 is only necessary to find the weight of an equal volume 
 of hydrogen ; which we obtain by subtracting the loss of 
 the jar when filled with that gas, from the weight of the 
 
64 HYDROGEN. 
 
 atmospheric air contained in it. The weight of the gas 
 thus found, divided by that of atmospheric air, gives the 
 specific gravity of hydrogen. This you will probably bet- 
 ter understand from an 
 
 EXAMPLE. Supposing the jar, when the air is exhausted 
 from it, loses 14 T 4 o- grains ; supposing further, that by intro- 
 ducing the hydrogen, instead of the atmospheric air, the jar 
 loses 13 T 4 <y grains. Query. What is the specific gravity of 
 hydrogen ? Ans. By the first supposition it is evident that 
 the atmospheric air which is contained in the jar weighs 14^y 
 grains ; by the second it is plain that the weight of an equal 
 volume of hydrogen is only 1 grain ; because 1 grain and 13^ 
 grains (the difference) make 14 T V grains ; consequently the 
 specific gravity of atmospheric air is to that of hydrogen as 
 14^7 is to 1 ; or in other words, atmospheric air is more than 
 14 times heavier than hydrogen. 
 
 Dividing 1 by 14 T %, or, which is the same, } by -Y^S we 
 obtain T j = 0,069 for the specific gravity of hydrogen ex- 
 pressed in decimals. 
 
 Fig. LXXVI. 
 
 ANOTHER EXPERIMENT, which shows the 
 levity, and at the same time the combustiblity 
 of hydrogen gas, is represented in Fig. LXXVI. 
 A jar with a narrow tube passed air-tight 
 through its cork, is filled with hydrogen, and 
 the flame of a candle applied to the open 
 end of the tube. The gas, which by its lev- 
 ity escapes through the tube, will instantly be 
 kindled and throw out great light. As the gas 
 is gradually ascending, it nourishes the flame, 
 which will continue to burn until the whole 
 quantity of hydrogen is consumed. 
 
 17. The decomposition of water by galvanic elec- 
 tricity is not the only means of obtaining hydrogen gas, 
 for in this manner it is only obtained in small quantities ; 
 although in its purest state. There are yet two principal 
 ways of procuring this gas, which we shall now ex- 
 plain. 
 
 The first is by suffering the hot vapors from boiling water 
 to pass through an iron gun-barrel ; by which means the 
 steam becomes decomposed into hydrogen and oxygen gas ; 
 the oxygen combines with the iron and the hydrogen is 
 
HYDROGEN. 
 
 65 
 
 Fig. LXXVII. 
 A 
 
 fiven off. This is the commonest way of obtaining it. 
 ig. LXXVII represents the apparatus used for this pur- 
 pose. B C represents the gun-barrel, which contains in 
 its centre a piece of coiled iron-wire, and is placed across 
 a portable wind-furnace, for the purpose of heating it red 
 hot. The retort, G, the neck B, of which fits air-tight into 
 the barrel, JB C, is partly filled with water which is heated 
 and converted into steam by means of an Argand's or spir- 
 it lamp, L. The steam thus formed is conducted into the 
 barrel, where by the affinity of the red hot iron for oxygen, 
 it is decomposed into its gaseous elements, oxygen and 
 hydrogen ; the former combining with the iron, and the 
 hydrogen passing through the pipe P, and the pneumatic 
 tub, into the receiver, R. 
 Fig. LXXVIII. 
 
 A still more convenient way of 
 obtaining hydrogen gas in great 
 quantities is the second, repre- 
 sented in the adjoining figure 
 LXXVIII. It consists in decom- 
 posing water by means of zinc* 
 and sulphuric acid. For this pur- 
 pose a few small pieces of zinc, and 
 about a gill of water with nearly one fifth as much sulphuric 
 acid, are placed in a common Florence flask F, through 
 the neck of which a small pipe, P, leads to the receiver, R. 
 The hydrogen is in this case formed by the decomposition 
 of water by the joint action of the zinc and the sulphuric 
 
 * Iron filings, nails, or tacks, are also frequently used for the same 
 experiment, instead of the zinc. 
 
 6* 
 
66 HYDROGEN. 
 
 acid. This is effected by a predisposing affinity of the 
 acid for a combination of oxygen and zinc, in the manner 
 explained in the Introduction, page 9. The metal attracts 
 the oxygen of the water ; and is in this state dissolved by 
 the acid, setting the hydrogen free, which will escape 
 through the pipe P, into the receiver. This is one of 
 the cheapest and quickest ways of obtaining hydrogen in 
 large quantities. 
 
 Qweri/ Which of the substances here enumerated exer- 
 cises a predisposing affinity for the oxygen? Jlns. The 
 acid ; because it predisposes it for a combination with the 
 zinc. 
 
 18, Application of hydrogen gas to Aerostatics. 
 The great levity of hydrogen gas has given rise to one 
 of the boldest undertakings which ever characterized hu- 
 man intrepidity that of attempting to navigate the atmos- 
 phere. A small ball filled with hydrogen, provided it be 
 not made of too heavy a material, will be lighter than 
 the atmospheric air which surrounds it, and will therefore 
 be forced upwards by the pressure of the atmosphere. This 
 you may see from the following 
 
 Fig. LXXIX. EXPERIMENT. Fill a 
 
 bladder with hydrogen 
 gas (how this is done by 
 means of Priestley's bell- 
 glass, has already been 
 explained in the Intro- 
 duction, page 31); in- 
 sert a narrow pipe into 
 the neck of the blad- 
 der, and dip its mouth 
 in a solution of soap and water ; you may then open the stop- 
 cock and by squeezing the bladder gently, in order to force 
 the gas into the solution, small bubbles will be formed, which 
 will rapidly ascend in the air. 
 
 Upon this experiment is founded the construction of 
 balloons for ascending in the air. The whole consists in 
 confining hydrogen gas in a spherical cover, which must 
 be sufficiently thin and light, in order that with the hy- 
 drogen gas which it contains, it shall weigh less than the 
 quantity of atmospheric air which it displaces (Natural 
 
PYDROGEN. 67 
 
 Philosophy, Chap. IV). For small experiments, a bal- 
 loon may be made of thin letter-paper ; but then it must 
 at least have from 6 to 7 inches diameter, otherwise it will 
 not rise. Such a balloon may weigh from 35 to 36 grains, 
 and contain about 5 grains of hydrogen. This will be 
 sufficient for its ascent, because its whole weight will only 
 be little over 40 grains, whereas the quantity of atmos- 
 pheric air which it displaces is more than 50 grains. If 
 the balloon is destined to draw up other heavy bodies, then 
 it requires, of course, a much larger diameter. The cover 
 is then made of varnished silk, in order that the exterior 
 air may be completely excluded from it. A balloon of 20 
 Fig. LXXX. feet in diameter may contain 4190 cubic 
 feet of hydrogen gas, and will be capable, 
 in addition to its own tegument, to carry 
 with it 255 Ibs. of other substances, such 
 as ropes, and a small boat in which a man 
 may be seated without inconvenience. If 
 the balloon is 30 feet in diameter then 
 it may contain 14, 142 cubic feet of hy- 
 drogen gas, and carry a burthen of near- 
 ly 1000 Ibs. Several persons may then 
 be seated in the boat, or basket, attached 
 to the balloon, and ascend several thou- 
 sand feet in the atmosphere with astonishing rapidity. 
 
 The hydrogen gas prepared for this purpose, is generally 
 obtained from a mixture of iron or zinc (commonly the former) 
 with sulphuric acid and water 12 oz. of iron and as much 
 sulphuric acid, with 2 Ibs. of water are supposed to yield 1 
 cubic foot of the gas. 
 
 Mixture of Hydrogen with Oxygen Inflammable, gas. 
 
 19. Hydrogen mixes with oxygen in all proportions ; 
 and such is the affinity between these two substances that 
 although hydrogen is 16 times lighter than oxygen, it re- 
 mains throughout equally diffused in oxygen, contrary to 
 the laws of aerostatics (see Natural Philosophy, Chap. 
 IV). This may easily be shown by the following 
 !o nsi'I'Mie j-?'? v .5.'xvi &v/ i;yu? 
 
O HYDROGEN. 
 
 Fig. LXXXI EXPERIMENT. Take two glass phials, a, b, 
 into the corks of which insert a narrow glass 
 tube, several inches long. Fill one of these 
 phials with oxygen and the other with hydro- 
 gen. Place that which is filled with oxygen 
 with its mouth upwards and insert in it the 
 cork with the tube ; the second cork at the 
 other end of the tube, fit to the mouth of the 
 phial filled with hydrogen gas, which must be 
 placed with its mouth downward. Now ac- 
 cording to the laws of gravity, the oxygen, 
 which is the specific heavier body, ought to 
 remain in the lower phial, and the hydrogen 
 ought to remain in the upper ; but quite the 
 reverse takes place. The hydrogen decends, 
 and the oxygen ascends, although oxygen is 16 times heavier 
 than hydrogen. After several hours the two gases will be 
 equally diffused in both phials ; and when a light is applied to 
 either of them an explosion will take place, which will be 
 strongest and loudest when the two gases are mixed in the 
 proportion of two volumes of hydrogen with one of oxygen. 
 Such a mixture of hydrogen and oxygen is called inflammable 
 gas. The product of its combustion, when ignited by an 
 electric spark, or the flame of a candle, is water. Hence it is 
 not only in our power to decompose water into oxygen and hy- 
 drogen, but we can also reproduce it by the combination of 
 hydrogen with oxygen in a proper proportion. 
 
 Several chemists have attempted to account for the explo- 
 sion which accompanies the combustion of inflammable air. 
 A very plausible reason on this subject is given by Mr Schubert, 
 Professor of Chemistry in Berlin. He attributes the explo- 
 sion to the steam which, in his opinion, is forming during the 
 combustion. For the heat which is given off when the gas is 
 ignited is so great thfct the water which is formed is instantly 
 converted into steam ; this expands itself suddenly ; but upon 
 being brought in contact with the colder air is suddenly con- 
 densed and creates a vacuum, into which the surrounding air 
 rushes with great violence. 
 
 20. When one volume of hydrogen gas is mixed with 
 two volumes of atmospheric air, another inflammable gas is 
 formed, whose effects, however are much inferior to those 
 of the mixture we have just spoken of. 
 
^YDROGEN. 
 
 69 
 
 Fig. LXXXII. 
 
 EXPERIMENT. Take a hollow tin 
 vessel, shaped as represented in figure 
 LXXXII, and fill it with hydrogen gas. 
 Fit a cork to its mouth, and provide it in 
 T with a touch-hole. When the flame 
 of a candle or an electric spark is appli- 
 ed to the touch-hole T, the cork will be 
 driven out with considerable force and 
 with a loud report. This apparatus 
 has received the name of the Hydrogen- 
 gun. 
 
 Query. What is the probable reason of the cork being 
 so violently thrown out, by the combustion of the inflamma- 
 ble gas in the gun ? Ans. Because by the combustion of 
 the hydrogen gas, water is formed ; which, owing to the great 
 heat given out, is instantly converted into steam ; and proba- 
 bly expanded to such a degree as not only to make up for the 
 condensation of the gases, (which have been consolidated into 
 water) but also to exercise a considerable pressure upon the 
 cork, which is by that means expelled. 
 
 From what we have said of the combustibility of hydrogen 
 gas, and its inflammable mixture with atmospheric air we 
 may perhaps be able to explain the following 
 
 Fig. LXXXIII. 
 
 EXPERIMENT. Take a common Florence 
 flask (see Fig. LXXXIII,) which either fill with 
 hydrogen gas, or with zinc, sulphuric acid and 
 water, in order to produce hydrogen gas in it. 
 Through the cork of this phial pass a small, nar- 
 row tube, through which the gas is allowed to es- 
 cape ; light the gas at the mouth of the pipe, and 
 introduce the flame in a glass tube of sufficient 
 diameter. As the hydrogen is burning in the 
 tube musical sounds will be produced which will 
 be grave or acute, according as the tube is long 
 or short, or as the flame is deeper immersed in 
 it. Some philosophers consider these sounds 
 as a continued series of explosions in the tube : 
 others consider them occasioned by currents of 
 atmospheric air which are partly produced by the consump- 
 tion of oxygen, and partly by the expansion and contraction of 
 the heated air and steam in the tube. 
 Great caution must be used not to light the gas too soon, 
 
70 
 
 H Yf D R O G E N . 
 
 but to wait until the ascending hydrogen has expelled all the 
 atmospheric air in the tube, otherwise inflammable air would 
 be formed which would explode and burst the tube, and per- 
 haps injure the experimenter. 
 
 When soap bubbles are blown with inflammable air (a 
 mixture of hydrogen and oxygen) instead of hydrogen, 
 (see fig. LXXIX, page 66,) and when floating in the air 
 are touched by the flame of a candle, they give a report 
 as loud as a gun, and sometimes even more loud and 
 stunning. 
 
 Fig. LXXX1V. 
 
 21. A most impor- 
 tant application of the 
 properties of inflamma- 
 |f ble air to chemical pur- 
 poses is Hare's* oxy-hy- 
 drogen blow-pipe. It 
 consists of two air or gas- 
 holders, A, B, of which 
 one is filled with oxy- 
 gen, and the other with 
 hydrogen. The two 
 tubes, L and 1, commu- 
 nicate with these gas- 
 holders, have a common 
 opening, and are each 
 provided with a turn- 
 cock, G, g, to regulate the discharge of the gases, either 
 jointly or separately, and in any proportion we please. The 
 substance, which is to be exposed to the action of this appa- 
 ratus, is commonly placed upon a piece of charcoal directly 
 under the common opening. The way of using this appa- 
 
 * DrR. Hare, of Philadelphia, was the first who suggested the idea 
 of constructing a blow-pipe with a mixture of hydrogen and oxygen. 
 Long after him, in 1816, (Hare published his discovery in 1802,) 
 Newman, an English chemist, constructed the compound blow-pipe, 
 described on page 72, Fig. LXXXV. But Prof. Hare's apparatus 
 has the vast advantage of being safe, convenient, and much less lia- 
 able to the dreadful accidents which have already but too frequently 
 occurred with Newman's apparatus, 
 
HYDROGEN. 71 
 
 ratus is this. When the two gas-holders, A and B, 
 are filled with hydrogen and oxygen respectively, (for which 
 purpose both gas-holders may be fitted to a wooden tub or 
 cistern, filled with water) the funnels, F f, are filled with 
 water, which, when the stop-cocks, m, , are opened, 
 is suffered to descend through the tubes, T and t, to the 
 bottom of the gas-holders ; thereby forcing the gas upwards 
 into the pipes, L, and 1. (The two stop-cocks, P, p, 
 serve for no other purpose than to confine the gas in the 
 holder when the pipe is not used.) The turn-cocks, 
 G and g, being now opened, the gas is ignited at their com- 
 mon opening, and the jet directed to the substance which 
 is to be exposed to its heat. 
 
 The effects of this apparatus surpass really the most 
 sanguine imagination the heat produced by it being in 
 some instances even superior to that produced by galvanic 
 electricity. Common iron wire exposed to the flame does 
 not only instantaneously melt, but actually boils like liquid 
 water ; platinum wire melts so fast that it runs down in 
 drops from 3 to 5 grains in weight ! Incombustible sub- 
 stances, such as flint, crystal, opal, jaspis, sapphire, eme- 
 rald, &/c, are almost instantaneously converted into a 
 glassy mass. Gold is totally vaporised and even dia- 
 monds, which require for their ignition the most power- 
 ful galvanic batteries, are in a very short time wholly 
 evaporated, when exposed to the burning jet of the com- 
 pound blow-pipe. In short, the results obtained by this 
 apparatus are so brilliant, and of so much importance to 
 chemical investigation, that it must be classed among the 
 most important and beautiful inventions, that have been 
 made in the science of chemistry. 
 
 22. The Blow-pipe with condensed or y gen and hy- 
 drogtn gaseSj although not an original invention of John 
 Newman (see the note on page 70,) is yet a highly useful 
 and powerful apparatus, and one for whose improved con- 
 struction we are indebted to this distinguished philosopher. 
 
HYDROGEN. 
 
 Fig. LXXXV. 
 
 It consists of a strong 
 gas-holder, A, commonly 
 made of copper, which 
 communicates by means 
 of a turn-cock E, with a 
 strong copper barrel, F, 
 which is used as a com- 
 pression pump. To the 
 'gas-holder, A, is fitted an 
 extremely narrow pipe 
 (about three inches long, 
 and only one eighteenth of 
 an inch bore), which, in H, is provided with a discharging- 
 cock. The compression pump F, communicates by the 
 turn-cock G, with a bladder filled with inflammable air 
 (1 volume of hydrogen mixed with two volumes of oxygen, 
 see 19). 
 
 When the apparatus is to be used, the two cocks, E and 
 G, are opened, and the piston of the compression pump 
 moved upwards. < By this means the air from the bladder 
 rushes into the barrel and thence into the gas-holder, from 
 which the atmospheric air must previously be exhausted. 
 The cock E is now closed and the piston of the compres- 
 sion pump moved down to compress the air in the gas- 
 holder. When this is done, the cock E is closed, and G 
 opened, when by raising the piston another portion of 
 inflammable air rushes into the vacuum created in the 
 barrel, which by a fresh stroke downwards is again forced 
 into the gas-holder ; and so can this operation be contin- 
 ued until the inflammable air in the gas-holder is suffi- 
 ciently condensed for the purpose in view. The cocks, 
 E and G are now closed, and the dischavging-cock open- 
 ed, and the gas, which rushes with great violence through 
 the orifice of the pipe B C, ignited. 
 
 The effect of this apparatus on various substances which 
 have been submitted to the heat produced by the burning jet, 
 is in every respect equal, if not superior, to those produced by 
 Hare's oxy-hydrogen blow-pipe ; but the apparatus is an ex- 
 ceedingly dangerous one. For should the flame at the mouth 
 of the pipe, C D, be by some means or other propagated to the 
 gas-holder, then a dreadful explosion would take place, which 
 
HYDROGEN. 73 
 
 would shatter the whole apparatus into fragments, and maybe 
 connected with the most distressing consequences to the ex- 
 perimenter. Prof. Hare's apparatus, on the contrary, is per- 
 fectly safe, produces nearly the same effects, and may be made 
 equally powerful, if not more so, by providing each of the gas- 
 holders with a compression pump, similar to that employed in 
 Newman's blow-pipe. 
 
 Combination of Hydrogen icith Oxygen Water. 
 
 23. EXPERIMENT. Take a glass bottle filled with hydro- 
 gen, or in which introduce some zinc, 
 kXXXVl. with a proper quantity of sulphuric 
 acid and water (as in experiment, page 
 65, Fig. LXXVIII); ignite the hydro- 
 gen which is then evolved at the mouth 
 of the pipe, and conduct it into a bell- 
 glass, which, instead of being open at 
 the bottom, must be shaped as represen- 
 ted in the adjoining figure (LXXXVI,) 
 having but a small opening for the 
 mouth of the conducting tube. The 
 product of the combustion will be the 
 well-known liquid water, which will 
 first appear as vapor, and finally run 
 down the sides of the glass, and collect 
 in small quantities in the cavities at the bottom of the bell- 
 glass. (Compare the experiment described page G3, Fig. 
 LXXIV.) 
 
 Query. What do you infer from this experiment ? Jlns. 
 That the water is a compound of hydrogen and oxygen. 
 Query Why ? Jlns. Because it is formed by the com- 
 bustion of hydrogen : and every combustion is a combination 
 of oxygen with the combustible substance, which in this case 
 is the hydrogen. 
 
 24. We have had occasion to remark before that 
 hydrogen and oxygen are evolved by the decomposition of 
 water ( 15) ; we have now seen that water is re-produced 
 from hydrogen and oxygen. It remains for us therefore 
 only to ascertain in what proportion hydrogen and oxygen 
 combine to water. We have stated in the Introduction, 
 (page 11) that all definite compounds are formed by the 
 combination in definite proportions of their elements 
 
 7 
 
74 
 
 HYDROGEN. 
 
 and we have already observed from the experiment descri- 
 bed on page 60, fig. LXXI, that a definite proportion of 
 hydrogen and oxygen is obtained from the decomposition 
 of water, which is one volume of oxygen to two volumes 
 of hydrogen. If we are now able to show that the same 
 proportion (two volumes of hydrogen to one volume of 
 oxygen) is also preserved in the combination of these 
 gases to water, then the chemical equivalent of water 
 would be established beyond any doubt or controversy. 
 This we are actually enabled to show by the following 
 
 EXPERIMENT. Procure a very strong 
 glass tube, abed, fitted to a brass cap, 
 cdcf, and provided in G with a stop- 
 cock. Two small holes must be drilled 
 in the upper part of this tube, into which 
 two small wires, M>, w;,must be cemented 
 in such a manner that their points nearly 
 touch each other on the inside. Provide 
 a mixture of pure hydrogen and oxygen in 
 the proportion of two volumes of the 
 former to one volume of the latter, with 
 which fill a jar, I, fitted with a stop-cock, 
 PI, to which the cock of the tube may be 
 screwed, in a manner similar to Priest- 
 ley's bell glass and bladder (Introduction, 
 pages 30 and 31). Extract the air from 
 the tube by an exhausting syringe or an 
 air-pump, and screw it tight to the jar. 
 When the two cocks are opened a portion 
 of the mixed gases will rush into the 
 tube ; this it is best to extract again from 
 the tube to make sure of the exhaustion 
 of any remaining air. Place the tube 
 
 again upon the jar, and by opening again 
 
 both cocks, fill it another time with the mixture of the gases ; 
 and take great care to close both stop-cocks. Now pass an 
 electric spark through the wires, and the gases in the tube will 
 explode (2 0, page, 69). Allow the tubes to cool; after 
 which let in a fresh portion of the mixture, whicn, when the 
 cocks are closed may again be inflamed and continue this 
 process until a strong dew is seen upon the interior of the tube 
 This upon examination you will find to be pure water. 
 
 If the two gases are mixed in the exact proportion ot two 
 
HYDROGEN. 75 
 
 volumes of hydrogen to one volume of oxygen, then the whole 
 mixture will be consumed; but if the mixture be made in 
 any other proportion, the excess of either gas will be left; 
 because they combine in no other. 
 
 Query Why must the glass tube in this experiment be 
 stronger than in others ? Jlns. Because it must resist the 
 explosion of the gases when an electric spark is applied to 
 them. Query Why must the two stop-cocks be carefully 
 closed before the electric spark is passed through the wire ? 
 Jlns. Because one volume of oxygen and two volumes of hy- 
 drogen form a highly explosive mixture ( 20, page 69); 
 consequently if the cocks were not closed the inflammation of 
 the gases in the tube would communicate itself to the jar, and 
 cause an explosion which would destroy the jar, and endanger 
 the safety of the experimenter. Query And what fact does 
 this experiment tend to establish ? Jlns. It establishes the 
 indisputable fact that water consists of two volumes of hydrogen 
 combined with one volume of oxygen, and that these gases com- 
 bine in no other proportion to water than in that of two vol- 
 umes of hydrogen with one volume of oxygen, 
 
 25. The law which we have just found respecting 
 the combination of hydrogen and oxygen corroborates 
 what we have stated in the Introduction {page 11) in ref- 
 erence to the composition of all definite compounds. Now 
 as hydrogen is the lightest ponderable substance in nature, 
 it will combine in the smallest proportion by weight with 
 all other substances ; consequently, if the weight of hy- 
 drogen which combines with oxygen is taken for unity of 
 comparison, the chemical equivalent of oxygen is 8 ; be- 
 cause 1 volume of oxygen weighs 8 times as much as the 
 two volumes of hydrogen with which it combines ; hydro- 
 gen being 16 times lighter than oxygen.* But the chem- 
 ical equivalent of oxygen and hydrogen being known, that 
 of water follows of course. This is composed of 
 I equivalent of hydrogen equal to 1 
 
 and 1 equivalent of oxygen, equal to 8 
 
 consequently chemical equivalent of water equal to 9. 
 
 * Two sixteenths is the same as one eighth ; consequently the 
 weight of the two volumes of hydrogen is only one eighth of the 
 weight of one volume of oxygen; or, which is the same, the weight 
 of the hydrogen employed is to that of the oxygen as I to 8. 
 
76 HYDROGEN. 
 
 In a similar manner have the chemical equivalents of oth- 
 er substances been determined in reference to hydrogen ; 
 and we shall make it a rule for the remainder of this trea- 
 tise, to write at the head of each substance, its equiva- 
 lent number ; and if the body we treat of is a compound, 
 then we shall besides this, affix the chemical equivalents 
 of its elements. 
 
 Some philosophers have assumed oxygen as the standard 
 of comparison, which being supposed equal to 100, the chem- 
 ical equivalent of hydrogen is one eighth part of ICO, or 12,5. 
 Most English and American chemists however prefer the for- 
 mer method, on which account we have adopted it throughout 
 this treatise. 
 
 26. The composition and decomposition of gases 
 follow a still more simple law, which is that of combining 
 in definite volumes, instead of definite weights. Thus, when 
 one gas combines with another, 1 volume of the one, 
 combines always with 1, 2, 3, 4, &.c, volumes of the oth- 
 er, and in no intermediate proportions. 
 
 27. Properties of water. Water, in its pure state, 
 is destitute of color, taste, or smell, and is on this ac- 
 count most admirably fit to be the natural drink of man. 
 It is the most universal solvent in nature, (dissolves most 
 solid substances) and absorbs many of the gases, such as 
 hydrogen, oxygen, nitrogen, &c. A cubic inch of dis- 
 tilled (purified) water weighs about 252 grains. Its great- 
 est density is at the temperature of 40 degrees ; it freezes 
 at 32, and becomes converted into stearn at the tempera- 
 ture of 212 Fahrenheit. According to the nicest exper- 
 iments, it is composed of 28 T f <y grains of hydrogen, and 
 224 T 4 3 6 ^ of oxygen ; the volume of hydrogen is 1325 cubic 
 inches, and that of oxygen 6(>2 ; so that the condensation 
 of these gases in the act of forming water, is nearly 2000 
 volumes into one ! 
 
 Query From what has just been observed respecting the 
 enormous condensation of the volumes of the gases which 
 are employed in the formation of water, can you now account 
 for the great heat given off during the cornhustion of hydro- 
 gen? JJns. When hydrogen is burnt nearly 2CCO volumes 
 of gas (hydrogen and oxygen) are condensed into one ; by 
 
HYDROGEN. 77 
 
 which means the heat which was hidden in the gas becomes 
 sensible, and produces the astonishing effects of the compound 
 blow-pipe, and the explosive mixture of hydrogen and oxygen. 
 
 We have said that the greatest density of water is at about 
 40 of Fahrenheit's thermometer. In this respect it makes 
 an exception to all other liquids, which are known to contract 
 as they cool down to their freezing points. (Natural Philoso- 
 phy, Chap. VI.) This peculiarity of water is of the greatest 
 influence upon the economy of nature. The water which 
 nearly covers one third of the earth, becomes a most efficient 
 means of equalizing its temperature, making those parts hab- 
 itable which would otherwise be buried in perpetual frost, or 
 scorched with insufferable heat. The cold air from the polar 
 regions absorbs the heat from the great waters or lakes until 
 they are cooled down to 40 degrees Fahrenheit. At this point 
 the refrigerating influence of the atmosphere nearly ceases ; 
 because the uppermost stratum of water, by further cooling, 
 becomes lighter (loses its density) and instead of sinking to 
 the bottom, remains in a cake of ice suspended at the surface, 
 preventing thereby the water below from being further expos- 
 ed to the influence of the colder air. Without, this peculiar 
 property of water, the cold air would continue to rob it of its 
 heat until the whole should be cooled down to 32 degrees, 
 when it would at once settle into a solid mass. Every living 
 creature in it would perish ; the ice in the northern regions 
 would never be liquefied, and navigation finally made impossi- 
 ble.* 
 
 28. Jce. Water in the act of freezing or congeal- 
 ing (see Natural Philosophy, Chap. VI,) expands by 
 nearly J of its volume, and so great and violent is this 
 expansion, that it bursts tubs, casks, water-pipes, &c, in 
 which water is suffered to freeze. It also explains why 
 trees and plants are destroyed in hard frosts, and such 
 similar phenomena. The specific gravity of ice is less 
 than that of water, viz, only T 9 ^, or 0.92, that of water 
 being I. This is the reason why the ice remains at the 
 surface of the water, and explains the phenomena alluded 
 to in the preceding paragraph. 
 
 * Library of Useful Knowledge, treatise on Chemistry. 
 
 7* 
 
78 HYDROGEN. 
 
 29. Rain, River, and Pump-water. We distin- 
 guish yet between Rain, River, and Pump water. The 
 purest of these is rain-water, because descending through 
 the atmosphere, it is least exposed to the influence of other 
 substances. JVext to it comes River water, which however 
 is often known to contain certain salts of soda, lime, and 
 magnesia, of which we shall speak in the 4th Chapter. 
 These two kinds of water are called soft water, in oppo- 
 sition to the hard pump-water, which contains always a 
 greater or less quantity of carbonic acid. Mineral waters 
 contain gases and salts in such proportions that they are 
 only used as physics in medicine. Sea water contains a 
 variety of salts. Among these are common salt, Glau- 
 ber's salt, muriate of lime and of magnesia. The two 
 last-mentioned ingredients give it that disagreeable taste 
 and smell, which causes nausea and vomiting when taken 
 into the stomach. 
 
 30. AH kinds of water contain atmospheric air 
 (generally from 3 to 4 per cent), not indeed as a chemical 
 ingredient^ but mechanically mingled with their particles. 
 From this water may be freed either by the air-pump, 
 or by boiling. The latter method is preferable. 
 
 When water is brought under the receiver of an air-pump 
 and the air is exhausted in the receiver, the particles of atmos- 
 pheric air which are mechanically intangled in the water, rise in 
 little bubbles to the surface and expand themselves in the vacu- 
 um created over the water, according to the laws of elastic 
 fluids (Natural Philosophy, Chap. IV). The boiling of water 
 consists in heating it until it becomes converted into steam. 
 Just before this takes place the water is thrown into a violent 
 agitation, partly occasioned by the expansion of the atmospheric 
 air contained in it ; little bubbles of air rise to the surface and 
 escape along with the steam which is forming during the pro- 
 cess of ebullition. 
 
 31. Water, although a tolerably good conducter of 
 Electricity, (Natural Philosophy, Chap. VIII), is a very 
 bad conductor of heat. Of this we can easily convince 
 ourselves by the following 
 
HYDROGEN. 79 
 
 Fig. LXXXVIII. 
 
 EXPERIMENT. Place a small air-thermometer 
 capable of showing very minute alteration of tem- 
 perature, in a jar filled with water, so that the bulb 
 of the thermometer may be a little below the sur- 
 face. Upon this pour a small quantity of ether, 
 which being specifically lighter than water, will 
 remain on top and may be inflamed. The ether 
 will burn for a considerable time without affecting 
 the thermometer in any sensible degree. 
 
 It will indeed be quite a different case when the heat is 
 applied to the water from below. In this case the ther- 
 mometer is soon affected. But then it is not the conduct- 
 ing power of water which transfers the heat from the bot- 
 tom of the jar to the surface and the thermometer ; it is 
 because the heated particles of water themselves are ex- 
 Fig, LXXXIX. 
 
 panded and rise to the surface, while another por- 
 tion of colder water sinks from the surface to the 
 bottom and occupies their place. This motion 
 can actually be observed by boiling water in which 
 some particles of amber or of some other light sub- 
 stance are diffused, in a glass tube applying the 
 heat from below. The particles of amber will be 
 seen to rise from the bottom of the tube, being car- 
 ried along by the particles of water to which they 
 adhere, while those near the surface will be ob- 
 served to descend with the colder particles of 
 water. The same experiment may be made with 
 other liquids, all of them being bad conducters of 
 heat, and capable of being heated only in conse- 
 quence of the mobility of their particles. (See 
 Natural Philosophy, Chap. VI.) 
 Query Could water be very well heated without the 
 mobility of its particles, which enables those which are 
 heated to ascend, making thereby room for the colder ones to 
 
80 HYDROGEN. 
 
 descend and become heated ? dns. No ; because the con- 
 ducting power of water in itself is very bad, as we have seen 
 from the experiment described in Fig. LXXXV1II. Ques. 
 And what is the reason that the burning ether on the surface 
 of the water in that experiment, does not materially affect the 
 thermometer? Ans. Because the heated particles on the 
 surface of water, becoming specifically lighter, must of course, 
 from hydrostatic principles, remain on top, and prevent thereby 
 the next lower particles from ascending. And in this consists 
 the whole difference between heating a liquid from below and 
 above (applying the heat at the bottom or at the surface). 
 
 32. It has been stated in Natural Philosophy, Chap. 
 VI, that the pressure of the atmosphere, or of steam, is an 
 obstacle to the boiling of liquids and consequently also to 
 the boiling of water. This has been stated as a reason 
 why water boils sooner under the receiver of an air-pump, 
 from which the air has been exhausted, or on the top of 
 high mountains, where the pressure of the atmosphere is less 
 than on the plain, &c ; but we can illustrate this law still 
 more strikingly and satisfactorily by the following 
 
 Fie XC EXPERIMENT Adapt a cork covered with a 
 
 thick coating of sealing wax, to a glass flask, 
 into which put water to the depth of about one 
 inch. Place it over a lamp until it boils, and 
 suffer the boiling to continue for a short time, 
 after which introduce the cork air-tight and re- 
 move the flask from the lamp. The water will 
 boil a little while after the heat ceases to be ap- 
 plied ; but on plunging the flask into ajar filled 
 with cold water or ice, the boiling recommences 
 with great violence and continues until the wa- 
 ter in the flask is nearly cold. Jf the flask is ta- 
 ken out before the boiling ceases, and is plunged 
 into hot water, the boiling immediately stops ; 
 but upon being again introduced into cold water the boiling 
 recommences with violence. 
 
 Qutry. Why is the cork in this experiment introduced 
 during the boiling of the water in the flask? Ans. It is 
 done in order to exclude the atmospheric air, and to prevent 
 the escape of the steam with which the flask becomes filled 
 when the water boils in it. Ques. Why does the water con 
 tinue to boil for a little while after the heat ceases to be ap- 
 
HYDROGEN. 
 
 81 
 
 plied to it? Ans. Because when the flask is removed from 
 the lamp, its sides come in contact with the cold atmospheric 
 air, which condenses part of the steam, and by this means 
 lessens the pressure on the surface of the water ; this enables the 
 water to boil for a short time, although its temperature is re- 
 duced. Qites. But why does the water recommence boiling 
 when the flask is plunged into cold water or ice ? Jlns. Be- 
 cause the steam in the flask becomes then suddenly conden- 
 sed, removing thereby the whole pressure from the water, and by 
 that means throws it into a state of violent ebullition. Ques. 
 And why does the boiling cease when the flask is introduced 
 into hot water ? JJns. Because this leads to the formation 
 of afresh quantity of steam in the flask, whose pressure pre- 
 vents the boiling of the water. Qucs. And what inference 
 should you draw from the experiment you have just explained ? 
 Jlns. That water (and all other liquids) require higher degrees 
 of temperature to boil under a heavy pressure of air or steam ; 
 and considerably lower degrees of temperature to boil token this 
 pressure is removed from them. 
 
 33. Water absorbs constantly a portion of heat, with 
 which it either combines, or through the medium of 
 which it becomes converted into vapor. The quantities 
 of heat or caloric thus absorbed by the large waters on 
 our globe, tend in no small degree to moderate the tem- 
 perature of the torrid regions, and to create an agreeable 
 freshness near the banks of rivers and on the seacoast. 
 This continued formation of vapors from the surface of wa- 
 ter is called the process of evaporation, and it serves some 
 of the most important purposes of nature. The vapors of 
 water contained in the atmosphere form mists or clouds, 
 which when brought in contact with the higher, and 
 consequently colder strata of air, are condensed and de- 
 scend again as dew, rain, or snow, to moisten our fields in 
 summer, or to protect them during the winter ; assisting 
 thereby the vegetation of trees and plants, without which 
 animal life itself would soon become extinct. (See Natu- 
 ral Philosophy, Chap. VI.) 
 
 The refrigerating influence of forming vapors of liquids may 
 be illustrated on a small scale by the following 
 
fcYDROGEN. 
 
 Fig. XCJ. 
 
 EXPERIMENT. Pro- 
 vide a watch-glass filled 
 with water and place it 
 over a shallow vessel filled 
 with sulphuric acid, and 
 bring the whole under the 
 receiver of an air-pump. 
 As the air is exhausted 
 from the receiver vapors 
 will abundantly rise from 
 the water, which being 
 speedily absorbed by the 
 sulphuric acid (which has 
 a great affinity for water) 
 creates such a degree of 
 cold as to freeze the water 
 in a very short time. If 
 instead of sulphuric acid we employ ether, the same effect 
 will be produced ; but in this case the ether becomes vaporized, 
 and absorbs such a quantity of heat from the water as to con- 
 geal it. 
 
 A still better illustration of the cold produced by the 
 rapid process of evaporation may be given by means of 
 an instrument invented by Dr Wollaston, and which has 
 received the name of Cryophorus or Frust-bearcr. 
 
 Fi<r XCII. It consists of a narrow 
 
 glass tube of from 18 
 inches to 2 feet in length, 
 bent towards the end at 
 right angles (see Fig. 
 XCII,) and terminating 
 on both sides in bulbs. One of these bulbs is about half 
 filled with water ; this being made to boil expels the at- 
 mospheric air from the tube and the other bulb which re-r 
 mains filled with steam. The open bulb is then closed by 
 means of a blow-pipe (see Fig. XXXIX, page 26), When 
 the empty bulb of the instrument is now immersed in a 
 mixture of salt and snow, the vapors contained in it are 
 suddenly condensed, by which means a vacuum is created, 
 which removing the pressure upon the surface of the water 
 in the other bulb, produces such a rapid evaporation 
 as to freeze the water in it although at a distance of 24 
 
HYDROGEN. 83 
 
 inches from the ice, and notwithstanding the slow con- 
 ducting power of water. 
 
 The effects of evaporation are also happily illustrated in the 
 process of perspiration. The natural temperature of the human 
 body is from 9fi to 98 degrees Fahrenheit ; but when taking ac- 
 tive exercise, or exposed to a fire, or the heat of a hot summer's 
 day, this temperature would naturally be heightened to a de- 
 gree which would be injurious to health. This, however, is pre- 
 vented by the appearance of a watery fluid on the skin, which 
 by its evaporation exercises a cooling effect on the body and 
 reduces it to its healthy temperature. 
 
 Query But why is it dangerous to be exposed to a current 
 of cold air after the clothes have become moist with perspira- 
 tion ? Jlns. Because the rapid process of evaporation may 
 then reduce the temperature of the body to a degree which 
 may be equally injurious to health. 
 
 34. Disli/latinn of water. In order to obtain water 
 in its pure state it is necessary to distill it. For this pur- 
 pose we make use of a common still (see Fig. XXVI, 
 Fig. XCIII. 
 
 page 22). Small quantities may be obtained by heating 
 water in a flask A, over an Argand's lamp, and convey- 
 ing the steam which is formed, through a pipe, P, fitted 
 air-tight to the neck of the flask, into a receiver C, which 
 for thU purpose must be surrounded by water or other 
 means of reducing its temperature. The steam formed 
 by the boiling of the water in the flask is, in the receiver, 
 again condensed, and descends as liquid water through 
 the discharging cock, D, where it may be collected in a 
 
84 HYDROGEN. 
 
 vessel. The water thus obtained is free from all impuri- 
 ties, salts, &c, which remain at the bottom of the flask 
 A, after the water has been converted into steam, and is 
 used for chemical and medicinal purposes. 
 
 35. We have learned in Natural Philosophy (Chap. 
 VI), that when water boils it ceases to assume a higher 
 degree of temperature ; all the heat further added becom- 
 ing then hidden or employed in the formation of steam. 
 But if the vessel is closed in such a manner as to prevent 
 the steam from passing off, then the steam may be heated 
 to a much higher degree, and being concentrated in a 
 small space Is capable of exercising an immense pressure 
 This is taken advantage of in the construction of steam 
 engines. Water may in this manner be expanded to near- 
 ly 1700 times its volume ; 1 cubic inch of water giving 
 nearly 1 cubic foot (1728 cubic inches) of steam. 
 
 The principal properties of steam may be exhibited by 
 the following 
 
 Fig. XCIV. EXPERIMENT. Provide a glass tube of about 
 three fourths of an inch bore, and from 7 to 8 
 inches long. Close it at one end. and enlarge 
 it a little by blowing into it when softened by 
 the heat of a blow-pipe (see Introduction, Fig. 
 XXXVIII, page 26). Take a wooden rod about 
 10 inches long, and wrap apiece of wash-leath- 
 er about one end of it, just enough to form a 
 piston which will move freely up and down in 
 the tube. The glass tube may be passed 
 through a piece of cork wood, into which a fork 
 or some other sharp instrument may be stuck 
 for a handle, to hold the whole apparatus over 
 the flarnc of a lamp. The piston must not be 
 introduced in the tube until the air is expelled 
 from it, by the boiling for some time of the wa- 
 ter. The remainder of the tube being now fill- 
 ed with steam, introduce the piston a little way, 
 and plunge the tube into water. The piston will 
 instantly be driven down ; but by holding the 
 tube again over the flame of the lamp, the piston 
 is again driven upwards, and so may the piston 
 be alternately driven upwards and downwards 
 by repeatedly heating and cooling the water 
 in the bulb of the tube. 
 
HYDROGEN. 85 
 
 Query Why is the piston in this experiment driven down 
 when the tube is plunged into cold water? rfns. Because 
 by plunging the tube into cold water the steam is suddenly 
 condensed and a vacuum created, into which the piston is forced 
 by the pressure of the atmosphere. Ques. But why is the 
 piston moved up again when the bulb of the tube is again held 
 over the flame of the lamp ? ~4ns. Because the water in 
 the bulb resuming the process of boiling, is again converted 
 into steam which expands itself in the tube and forces the 
 piston upwards. Ques. What then is the principal cause of 
 the prodigious power of the steam-engine ? Jlns. The pro- 
 duction and sudden annihilation of the steam formed in the 
 boiler. (For the description of the steam engine, see the Ap*- 
 pendix). 
 
 With regard to the other applications of water to the pur- 
 poses of common life, we can only say that they are innu- 
 merable, as there is none of the arts which can dispense 
 with it, and its presence is absolutely indispensable to the 
 continuance of all animal and vegetable life on our globe. 
 
 36. Modes of ascertaining the purity of water. 
 Pure water being a great object to the physician, the 
 chemist, and the manufacturer, it may perhaps be desira- 
 ble to acquaint ourselves with some of the means of as- 
 certaining its purity. Chemically pure water must 
 
 1. Not redden Litmus paper, otherwise it is a sign 
 of its containing an acid ; 
 
 2. It must not form a precipitate when mixed with a 
 solution of acetate of lead ; for in this case it would con- 
 tain sulphuric acid ; 
 
 3. Mixed with lime-water it must not become turbid; 
 otherwise it would contain carbonic acid. 
 
 4. With a solution of potash it must not form a pre- 
 cipitate, because in this case it would contain earthy salts. 
 (See Chap. IV, Introd. to salts.) 
 
 5. It must not become turbid with a solution of Prus- 
 siate of iron and potash ; otherwise it contains metallic 
 salts, and especially iron, if the precipitate is blue, and 
 copper if the precipitate is brown. 
 
 In many cases it is only necessary to. know what pro- 
 portion the solid substances mechanically contained or 
 8 
 
86 HYDROGEN. 
 
 entangled in the particles of water, bear to the whole 
 volume of the liquid. For this purpose it is sufficient to 
 suffer a measured quantity of water to evaporate slowly 
 over a moderate fire, or from an evaporating dish made 
 of porcelain (see Fig. XXIV, page 21) and bedded in 
 sand. The dry residue, which is generally of a white 
 color, may then be weighed and compared to the volume 
 of water. 
 
 Deutoxide of Hydrogen or Oxygenized water. 
 
 Composition : 1 equivalent of hydrogen = 1 
 2 equivalents of oxygen = 16 
 
 Chemical equivalent of oxyg. water = 17. 
 
 37. Water was for a long time supposed to be the 
 only compound of hydrogen and oxygen. Another combi- 
 nation of the same elements has, however, been recently 
 discovered, which consists of equal volumes of hydrogen 
 and oxygen (water being a combination of 2 volumes of 
 hydrogen with 1 volume of oxygen). It is obtained by an 
 exceedingly tedious and expensive process, from a sub- 
 stance called Deutoxide of Barytium, but is nevertheless 
 used in Paris for divers processes in bleaching cambric 
 and calicos. It was discovered by Thenard, a celebra- 
 ted French Chemist, and consists, as we have stated, of 
 
 2 volumes of hydrogen = I 
 2 volumes of oxygen (each = 8) = 16 
 
 consequently its chemical equivalent is 17. 
 
 38. Properties of oxygenized water It is a color- 
 less liquid, of a metallic bitter taste, a highly disagreeable 
 nauseous smell, bleaches and dries the skin, destroys all 
 vegetable colors (on which account it is used in bleaching) 
 and may be mixed with water in all proportions without 
 being decomposed. 
 
 Metals brought in contact with it are speedily oxidized : 
 but silver and platinum thrown into it cause an explosion, 
 without suffering any visible change or oxidation a phe- 
 nomenon which has not as yet been satisfactorily ex- 
 plained. 
 
NITROGEN. 87 
 
 Recapitulation of the Binary Comb' nations of Hydrogen 
 and Oxygen. 
 
 / water, or protoxide of 
 ^ hydrogen, 
 Hydrogen combines with oxygen to 
 
 J Oxygenized water, or 
 V. deutoxide of hydrogen. 
 
 C. Nitrogen, or Azote. 
 
 Chemical equivalent = 14. 
 
 39. This is an inodorous gas, which is destitute of 
 color or taste, and constitutes about 79 per cent of the 
 whole weight of our atmosphere. It is but sparingly ab- 
 sorbed by water, enters largely into the composition of all 
 animal substances, but is of itself incapable to support 
 animal life. It is not inflammable and extinguishes all 
 burning bodies the moment they are introduced into it. 
 When separated from its combination with oxygen by the 
 influence of galvanic electricity, it adheres to the negative 
 pole, wherefore it is called a positively electric substance. 
 (See introduction, page 41.) 
 
 This gas has formerly been called azote, from a Greek word 
 signifying destroyer of life. This expression however is not 
 correct, for the gas is no poison it is merely incapable of 
 support ing life, or the process of respiration without the pres- 
 ence of oxygen. It is nevertheless taken into the lungs, as 
 we shall see hereafter, and is probably destined to reduce the 
 injurious effects which would be produced by the respiration 
 of pure oxygen. 
 
 40. Mode of obtaining Nitrogen. Nitrogen is prin- 
 cipally and easiest obtained, by separating it from atmos- 
 pheric air. This is done by burning phosphorus under a 
 bell-glass or receiver (see Fig LXV, page 54). During 
 the combustion the oxygen of the air in the bell-glass com- 
 bines with the phosphorus to phosphoric acid, which is 
 rapidly absorbed by the water over which the glass must 
 be placed. The residue of air, after all the oxygen is 
 consumed by the process of combustion, is nitrogen, which 
 
88 NITROGEN. 
 
 may be collected by means of a pneumatic tub, an appa- 
 ratus already frequently described in the preceding sec- 
 tions (see Introduction, Fig. XL1X, page 30). Nitrogen 
 may also be obtained from a variety of animal substances 
 particularly from meat, as we shall see in the 7th Chapter. 
 
 Mixture of Nitrogen with Oxygen Atmospheric Air. 
 
 41. Nitrogen and oxygen may be mixed in all pro- 
 portions, but four volumes of nitrogen with one volume of 
 oxygen form a mixture resembling in all essential proper- 
 ties our atmospheric air. 
 
 That nitrogen and oxygen are actually contained in the at- 
 mosphere in the proportion of 4 volumes of the former with 1 
 volume of the latter, is evident from the fact, that when a 
 candle is burnt under a receiver provided with a scale to indi- 
 cate the diminution of air during the process of combustion, 
 one fifth of the whole volume of air is always consumed by 
 the loss of oxygen, which agrees perfectly with the state- 
 ment we have just made.* This experiment has already been 
 described in Fig. LXVI1, page 56. 
 
 42. Atmospheric air. The atmosphere of the globe, 
 whose mechanical properties have already been described 
 in .Natural Philosophy (Chap. V), contains in addition to 
 nitrogen and oxygen which form its principal ingredients, 
 a greater or less portion of vapors of water and carbonic 
 acid gas a substance with whose properties we shall be- 
 come acquainted in the next chapter. The quantity of va- 
 por is continually varying, and depends upon the tempera- 
 ture and situation of the place, whether it is in the neigh- 
 borhood of large basins of water or removed from thesea 
 coast and the shores of rivers upon the season of the year, 
 and upon the particular hour of the day. We know that 
 in the spring and fall of the year the atmosphere is more 
 damp than in summer or winter ; and that the morn- 
 ings and evenings are generally misty or foggy during 
 those seasons. As regards the proportion of carbonic 
 
 * If 4 volumes of nitrogen and 1 volume of oxygen constitute at- 
 mospheric air, then the oxygen must be one fifth of the whole 
 volume. 
 
NITROGEN. 89 
 
 acid gas, it is greater in summer than in winter, and dur- 
 ing the night than in day-time. 
 
 If we abstract for a moment from the variable portion of 
 vapor of water contained in our atmosphere, we may suppose 
 it to be composed as follows: 
 
 21 per cent oxygen, 
 
 78f$j 9 (jdo. nitrogen, 
 
 ToVo d- of carbonic acid gas. 
 
 43. The proportion of the principal ingredients of 
 our atmosphere, nitrogen and oxygen, is invariably the 
 same, viz: 21 weights of oxygen to 79 weights of nitro- 
 gen, whether we examine the air on top of the highest 
 mountains, or at the level of the sea, under the equator or 
 in the polar region, in winter or in summer. 
 
 Gay Lussac, a celebrated French chemist, found no percep- 
 tible difference with regard to this ratio (21 weights of oxygen 
 to 79 of nitrogen) between the air at the height of 24,600 feet 
 above the level of the sea, and that of the most crowded thea- 
 tre in Paris. What is most wonderful and inexplicable in this 
 ratio, is its permanency, notwithstanding the prodigious con- 
 sumption of oxygen during combustion and in the various 
 processes of animal and vegetable life. 
 
 Many trials have been made to see whether no other mix- 
 ture of gases can support respiration and animal life as well 
 as our atmosphere ; but none has succeeded. If the proportion 
 of its mixture were changed, by an addition of nitrogen or a 
 diminution of oxygen, it is highly probable all animal and 
 vegetable life would cease ; while, on the contrary, by an addi- 
 tional quantity of oxygen or a diminution of nitrogen, all vital 
 energies, and consequently life itself would be exhausted too 
 rapidly. 
 
 44. Accidental ingredients of our atmosphere. Be- 
 sides the gases already enumerated, our atmosphere con- 
 tains at different times and places, a variety of other sub- 
 stances such, as carluretted hydrogen, in marshy coun- 
 tries and in the vicinity of coal mines ; sulphuretted 
 hydrogen, in the neighborhood of sulphur baths ; sulphu- 
 ric acid gas in the immediate vicinity and at the craters 
 of volcanoes, &c. 
 
 All bodies on our globe are continually exposed to the in- 
 fluence of the atmosphere. Most chemical phenomena take 
 
90 
 
 NITROGEN. 
 
 place in it. The processes of respiration, combustion, fermen- 
 tation, and putrefaction (see Chap. VII, on the spontaneous 
 decomposition of vegetable matter), are instances of its con- 
 tinual operation upon all animate and inanimate nature. It 
 has therefore become a matter of great importance to find 
 means of ascertaining its chemical composition at various times 
 and places, and so much has this become a subject of chemical 
 speculation that some chemists treat of it as a separate branch 
 of the science, which they call Eudiometry, signifying measure 
 of the quality of the atmosphere. We shall now proceed to 
 describe some of the apparatus used or suggested for this 
 purpose. 
 
 45. The object of Eudiometry in most cases is to 
 ascertain the quantity of nitrogen or oxygen contained in 
 the atmosphere. Any substance which will absorb or 
 consume all the oxygen from a confined portion of air, will 
 serve this purpose, provided this substance does not itself 
 mix with, or alter the volume of the nitrogen. An appa- 
 ratus constructed for this purpose is called a Eudiometer. 
 A great variety of them have been suggested, but the fol- 
 lowing three are the most useful, and commonly employed 
 by practical chemists. 
 
 1. AcharcTs Eudiometer by the slow 
 combustion of phosphorus. It consists of 
 a glass tube (see Fig. XCV), closed at 
 one end 6, where it is blown into a bulb 
 c. In this small sticks of phosphorus 
 are to be placed, about one third grain to 
 one cubic inch of atmospheric air ; the 
 remainder of the tube is then filled with 
 quicksilver, and with its open end down- 
 wards, placed into a jar filled with the 
 same metal. Atmospheric air is now 
 allowed to pass through the pneumatic 
 apparatus into the tube (quicksilver being 
 throughout employed instead of water), 
 and The oxidation of the phosphorus, 
 which has a great affinity for oxygen, increased by heat- 
 ing the bulb c, by the flame of a candle. The oxygen of 
 the atmospheric air in the tube will unite with the phos- 
 phorus, leaving a residue of nitrogen in the gradated tube 
 a b, from which, and the whole volume of atmospheric air 
 
 Fig. XCV. 
 
NITROGEN. 91 
 
 employed in the experiment, we are able to judge of the 
 quantity of oxygen consumed ; or, which is the same, of 
 the proportion in which oxygen entered in the composi- 
 tion of the atmospheric air employed in the experiment. 
 Thus, if one fifth of the whole volume of atmospheric air 
 should combine with the phosphorus, the remaining nitro- 
 gen would be four fifths of the whole volume employed ; 
 consequently the proportion of oxygen to nitrogen would 
 be as 1 to 4. 
 
 Fig. XCVI. 
 
 2. The Eudiometer by detonating Oxygen and 
 Hydrogen gas (see Fig. XCVt) is an invention of 
 Volta, and is founded on the principle that one 
 volume of oxygen combines with two volumes of 
 hydrogen to water (see 15, page 61). It con- 
 sists of a strong glass tube a, (see the figure) fitted 
 at one end to a brass box, which terminates on the 
 outside in a knob c, of the same metal, and is con- 
 nected with a piece of bent wire in the tube. 
 When the apparatus is to be used, the tube is fill- 
 ed with a mixture of two volumes of hydrogen and 
 one volume of atmospheric air, (which is easily done by 
 means of the pneumatic tub) and an electric spark ap- 
 plied to the knob c. The mixture of the gases in the tube 
 will explode ( 20, page 69) and the hydrogen combine 
 -with the oxygen of the atmospheric air to water ; the 
 quicksilver or water of the pneumatic tub, over which the 
 experiment must be made, will instantly rise in the tube 
 and show the volume of gas consumed ; one third of 
 which is always the oxygen contained in the atmospheric 
 air examined. 
 
 Instead of the Eudiometer just described, we may use the 
 apparatus Fig. LXXXVIT, page 74. The experiment is 
 nearly the same as that described on that page, with the 
 only difference, that atmospheric air is employed instead 
 of the oxygen. 
 
 Qwer?/ I5y what means, in the last experiment, are you 
 able to find the volume of oxygen contained in the atmospher- 
 ic air. Ans. By the combustion of the hydrogen, which, 
 with the oxygen of the atmospheric air combines to water. 
 
92 NITROGEN. 
 
 Ques. But what reason have you to infer that exactly one 
 third of the whole volume of gases consumed, is the quantity 
 of oxygen which was contained in the atmospheric air? 
 jjns. Because two volumes of hydrogen combine with ex- 
 actly one volume of oxygen to water, consequently of the 
 three volumes consumed, the oxygen constitutes necessarily 
 one third. 
 
 Fig. XCVII. 
 
 Gay Lussac's Eudiometer, which we are now 
 about to describe, is founded on the property of 
 some liquids to absorb certain gases, contained at 
 different times and places in our atmosphere. It 
 consists of a cylindrical jar, which is fitted to a 
 brass box, terminating in a neck, shaped like 
 that of a bottle, and provided with a cork, through 
 which a gradated tube may be made to com- 
 municate with the jar. When the apparatus is 
 to be used the gradated tube is first filled with 
 air, and then fitted to the jar, which must be 
 filled with such liquids as are capable to absorb 
 the gases which we suppose to be contained in 
 the atmospheric air under examination. The 
 whole apparatus is then inverted for some time, so that 
 the air from the tube may ascend into the jar and after- 
 wards, in its proper position, placed under water or quick- 
 silver ; the rise of the liquid in the tube will indicate the 
 quantity of gas absorbed, and thereby enable us to judge 
 of the ingredients contained in the atmosphere. 
 
 The various experiments which have been made with these 
 Eudiometers have convinced us that the oxygen contained in 
 the atmosphere is absolutely invariable, at all times of the day 
 and year. The great difference therefore which exists between 
 the air of certain places, and the great influence which the 
 atmosphere, at different times, has upon our state of health, 
 cannot be explained from the greater or less quantity of oxygen 
 which it contains, but is owing to certain principles which it 
 is impossible for us to determine with any degree of precision. 
 The different miasmas which at times are contained in the at- 
 mosphere, and are supposed to be the cause of the existence 
 or spreading of contagious diseases, escape likewise wholly 
 our observations ; their nature being entirely different from 
 any known element in chemistry. 
 
NITROGEN. 93 
 
 Combinations of Nitrogen with Oxygen. 
 
 46. Nitrogen combines with oxygen in five different 
 proportions, forming with it 2 oxides and 3 acids. (See the 
 nomenclature of oxides and acids, 4, page 51.) Their 
 names, according to their composition, are Protoxide of 
 nitrogen, Deutoxide of nitrogen, or nitric oxide, hypo- 
 nitrous acid, nitrous acid, and nitric acid. 
 
 Protoxide of Nitrogen. 
 
 Chemical Composition. : \ Equiv. Nitrogen = 14 
 1 do. Oxygen = 8 
 
 Chemical equiv. of Protoxide of Nitrogen = 22. 
 
 47. Protoxide of nitrogen' is never found in its sim- 
 ple state. It is altogether a product of art, and is best ob- 
 tained by the following 
 
 Fig. XCVIII. EXPERIMENT. Fuse a salt called JVr- 
 
 trate of ammonia in a retort over an Ar- 
 gand's or spirit lamp ; or as this salt is not 
 always readily obtained, prepare it from 
 a solution of carbonate of ammonia (the 
 principal ingredient of common smelling 
 salts) in diluted nitric acid. Evaporate the 
 solution until its consistency is such that a 
 drop taken out with a glass rod concretes 
 on cooling. When this is done, liquefy 
 the salt thus obtained, and keep it simmering by a gentle heat. 
 The gas will be given off in abundance, and may be collected 
 by the pneumatic tub. For this purpose however it is neces- 
 sary to conduct the pipe to the top of the receiver, as is shown 
 in the figure ; because the "as has a strong affinity for water, 
 and would otherwise be absorbed by it in a great proportion. 
 
 48. Properties of Protoxide, of Nitrogen, The 
 Protoxide of nitrogen is a coloiless gas of a sweetish taste, 
 and faint, agreeable smell. It becomes liquid by pressure : 
 is not inflammable, but supports combustion with more 
 splendor than common atmospheric air. Animals die in 
 it speedily. When breathed in small quantities it pro- 
 duces an exhilarating effect, similar to that produced by 
 spirituous liquors. It mostly occasions an irresistible 
 
94 NITROGEN. 
 
 propensity to laughter and muscular exertion ; but taken 
 in greater quantities produces swoon and apoplexy. 
 
 For the purpose of taking this gas into the lungs, we may 
 take Priestley's bell-glass instead of a receiver, and transfer 
 the gas which is collected in it to a bladder, from which it may 
 be breathed. Sir Humphry Davy is said to have inhaled 12 
 quarts of this gas. But this is rather a dangerous experiment ; 
 the greatest quantity of it inhaled at any one time ought not 
 to exceed 3 or 4 quarts, and even these are known to have 
 produced the most distressing consequences on the particular 
 constitution of individuals. 
 
 Protoxide of nitrogen may by electricity be again decom- 
 posed into its elements, nitrogen and oxygen. When mix- 
 ed with hydrogen it becomes inflammable, and on the ap- 
 plication of an electric spark detonates with great violence. 
 
 Its composition by volumes is one volume of nitrogen 
 with one volume of oxygen. Its chemical proportion or 
 equivalent by weights have been stated in the introduction. 
 
 It will however be well to say here a few words on the mode 
 of reasoning, or the species of chemical analysis by which 
 the equivalents of this gas have been determined. Two vol- 
 umes of hydrogen have been mixed with two volumes of Pro- 
 toxide of nitrogen, and detonated by means of an electric 
 spark in the apparatus described on fig. LXXXVII, page 74. 
 By this means the protoxide of nitrogen has become completely 
 neutralized, its oxygen combining with the hydrogen to water, 
 and the residue being exactly two volumes of nitrogen. 
 
 But we know that two volumes of hydrogen can neutralize 
 neither more nor less than one volume of oxygen, we infer 
 therefore that in protoxide of nitrogen there could not be ei- 
 ther more or less than one volume of oxygen, combined with 
 two volumes of nitrogen. If now we wished to determine the 
 proportion in which these substances are combined by weight, 
 it would only be necessary to know the weight of a given vol- 
 ume of both gases. 
 
 Taking therefore any given volume, say 50 cubic inches, for 
 the standard of comparison, we say, 
 
 50 cubic inches of oxygen weigh 16.8 grains 
 
 double this volume, or 100 cubic inches of nitrogen weigh 20.7* 
 
 * This has been found by experiment; or the weight of 50 cubic 
 inches of either gas may also be calculated from its specific gravity 
 wben compared to the weight of a cubic inch of water (see 27, 
 page 76.) 
 
NITROGEN. 95 
 
 consequently the chemical equivalent, or proportion by weight 
 of nitrogen, is to the chemical equivalent of oxygen (which we 
 know is 8 see page 75) as 29.7 is to 16.8 or which is the 
 same, we have the proportion. 
 
 16.8 : 29.7 ;; 8 : Answer = 14, nearly ; which 
 29.7 is therefore the chemical equiv- 
 g olent of nitrogen, or the proper- 
 ly aW:>7 *YIQQ tion in which it combines by 
 16.8^37.6(13.9 weight withall Qther substan . 
 
 ces. 
 
 656 
 
 504 
 
 15^0 
 1512 
 
 Now knowing the chemical equivalent of nitrogen and also 
 that of the oxygen, with which it combines to protoxide of 
 nitrogen, it is only required to add them together to obtain the 
 chemical equivalent of that substance, viz. 
 
 2 volumes or 1 equivalent of nitrogen = 14 
 and 1 volume or 1 equivalent of oxygen = 8 
 
 hence the chemical equivalent of deutoxide of nitrogen = 22, 
 which was to be proved. 
 
 D tut oxide of Nitrogen. 
 
 Chemical composition, 1 Equivalent of Nitrogen = 14 
 2 Equivalents of Oxygen, (each being 8) = 16 
 
 Chemical equivalent of Deutoxide of Nitrogen =30. 
 
 49. The deutoxide nf nitrogen, like the protoxide of 
 the same gas is not to be found in nature. It is a product 
 of art, and may be obtained by the action of nitric acid 
 (aqua-fortis) on some oxidable metal, commonly copper or 
 quicksilver (the latter is to be preferred). The metal 
 ought to be put into a retort, and the acid poured upon it, 
 when an effervescence will take place, and the gas which 
 is given off may be collected through the pneumatic tub. 
 To understand this process it is necessary to state that 
 nitric acid is :i combination of nitrogen with a greater 
 quantity of oxygen than is contained in the deutoxide, 
 and that by pouring it upon copper or mercury, for which 
 
96 NITROGEN. 
 
 oxygen has a strong affinity, part of its oxygen combines 
 with the metal, leaving just enough with the nitrogen to 
 form the deutoxide. 
 
 50. Properties of Deutoxide of nitrogen. We have 
 already stated at the head of this article that the deutox- 
 ide of nitrogen is a combination of nitrogen with a fur- 
 ther portion of oxygen. This compound is a colorless 
 gas, whose smell and taste are not known, because as soon 
 as it conies in contact with the atmosphere it combines 
 with a fresh portion of oxygen, and becomes converted in- 
 to vapors of nitrous acid. Jt is wholly irrespirable, perma- 
 nently elastic, sparingly soluble in water, arid does not, in 
 its pure state, act upon vegetable colors. It is not inflam- 
 mable, and a burning body immersed in it, is instantly ex- 
 tinguished ; but pieces of charcoal or phosphorus intro- 
 duced in a state of vivid inflammation burn in it with great 
 splendor, by virtue of the oxygen which it contains. 
 With hydrogen it may be mixed in any proportion without 
 exploding, but when burnt with it in atmospheric air, it 
 changes the yellow flame of the hydrogen into green. 
 
 When deutoxide or nitric oxide is mixed with oxygen 
 deep red fumes are generated, which, when the experiment 
 is made over the pneumatic tub, are speedily absorbed 
 by the water, so that if the gases are entirely pure, and 
 mixed in the proper proportion, they will wholly disappear. 
 If instead of pure oxygen common atmospheric air be 
 employed, the effect will be apparently the same; the 
 nitric oxide will combine with the oxygen of the air, and 
 be absorbed by the water over which the mixture is made, 
 the diminution in the volume of the gases being proportion- 
 ate to the quantity of oxygen contained in the jar. 
 
 Upon this property of the deutoxide of nitrogen, to combine 
 with the oxygen in atmospheric air, and in this state to be 
 absorbed by* water, is founded Gay Lussac's Eudiometer, de- 
 scribed on fig. XCVII, page 92. To a measured quantity of 
 atmospheric air in the tube (see that figure) is added a suffi- 
 cient quantity of deutoxide of nitrogen to combine with all 
 the oxygen contained in the air. The tube is then screwed to 
 the glass jar, filled with water, and the apparatus inverted to 
 allow the gas to ascend in the liquid, and to be absorbed by it. 
 When the apparatus is afterwards placed in its proper posi- 
 
NITROGEN. 97 
 
 tion, the diminution of oxygen will be perceived by the rise of 
 the water and its higher stand in the gradated tube. 
 
 51. Deutoxide of nitrogen may be decomposed by 
 suffering it to stand over iron-filings. A portion of its oxy- 
 gen will combine with the filings, and the gas will by this 
 means be converted into a protoxide (see 47). Its 
 composition (at the head of this article) has been inferred 
 from the fact that burning charcoal absorbs exactly one 
 half of its volume, leaving the other half pure nitrogen. It 
 must therefore consist of equal volumes of nitrogen and 
 oxygen ; or, which is the same, of 
 1 equivalent or proportion by weight of nitrogen = 14 
 and of 2 equivalents of oxygen (each being 8) = 16 
 
 whence Equiv. of Deutoxide of Nitrogen = 30. 
 
 Hyponitrous Acid. 
 
 Chemical composition : 1 equiv. of Nitrogen =14 
 3 do. Oxygen = 28 
 
 Chemical equivalent of Hyponitrous acid =42. 
 
 52. Hyponitrous acid is a conjectural or hypothet- 
 ical substance, which it is supposed is formed from a com- 
 bination of the deutoxide of nitrogen, with a further por- 
 tion of oxygen. It is said to be produced when 4 volumes 
 of that gas are mixed with one volume of oxygen, making 
 the experiment over mercury, on top of which a few drops 
 of a solution of potash must float. The deutoxide of nitro- 
 gen is then supposed to combine with the oxygen to an acid, 
 which immediately unites with the potash, but which after- 
 wards cannot be separated from it without decomposition. 
 
 Some chemists* pretend that at the common tempera- 
 ture of the atmosphere it appears as an orange colored 
 vapor, which is exceedingly injurious to the lungs. 
 
 * Prof. Schubert, of Berlin, and Gmehlea, in Heidelberg. 
 
 9 
 
98 NITROGEN. 
 
 Nitrous Acid. 
 
 Chemical composition : 1 equivalent of Nitrogen = 14 
 4 equivalents of Oxygen (each = 8) = 32 
 
 Chemical equivalent of Nitrous acid = 46 
 
 53. This gas may be produced like the hyponitrous 
 acid, by adding oxygen to the deutoxide of nitrogen. For 
 this purpose conduct two measures of the deutoxide and 
 one measure of oxygen into a glass retort fitted with a 
 stop-cock, and from which the atmospheric air has pre- 
 viously been extracted, either by an air-pump or an ex- 
 hausting syringe. (The experiment cannot be made over 
 water or mercury ; because these liquids have too great 
 an affinity for the compound, which would thus be genera- 
 ted). The two measures of the deutoxide and one measure 
 of the oxygen will be condensed into half their volume, 
 and form a deep orange colored gas, which is the nitrous 
 acid. 
 
 54. The combinations of nitrogen and oxygen 
 afford striking instances of the direct proportions in 
 which gases combine with each other by volumes. We 
 have seen that the protoxide of nitrogen was composed 
 of 2 volumes of nitrogen with 1 volume of oxygen ; the 
 deutoxide of nitrogen of 2 volumes of nitrogen with 2 
 volumes of oxygen ; and the hyponitrous acid, being form- 
 ed by adding 1 volume of oxygen to the deutoxide, is 
 equivalent to 2 volumes of nitrogen with 3 volumes of ox- 
 ygen ; finally the nitrous acid which is formed by adding 
 2 volumes of oxygen to 2 volumes of the deutoxide is ev- 
 idently equal to 2 volumes of nitrogen with 4 of oxygen ; 
 or, which is the same, to 1 volume of nitrogen with 2 vol- 
 umes of oxygen. 
 
 This verifies what we have stated in 26, page 76, 
 in reference to the combination of the gases, which is 
 always in the proportion of whole numbers by volume, 
 and in no intermediate ratio, affording a striking illustra- 
 tion of the harmony and simplicity of the laws of nature. 
 
 55. Properties of Nitrous acid. It is, as we have 
 said, a deep orange-colored gas, which is capable, by vir- 
 
NITROGEN. 99 
 
 tue of its oxygen, to support the process of combustion, 
 and is readily dissolved by water, which acquires by it 
 first a green, then a blue, and finally a yellow tint. The 
 solution tastes sour, reddens litmus-paper, and stains an- 
 imal substances yellow. No great application has been 
 made of this acid in the arts. 
 
 Nitric A cid. 
 
 Chemical composition : I equivalent of Nitrogen = 14 
 5 equivalents of Oxygen (each 8) =40 
 
 Chemical equivalent of nitric acid = 54. 
 
 50. Nitric acid (aqua-fortis) is found (in an engaged 
 state) combined with a number of mineral and vegetable 
 bases (Intr. page 38). It is easily obtained by art, when 
 deutoxide of nitrogen is passed very slowly into pure oxy- 
 gen gas, standing over water. By this operation 4 vol- 
 umes of the deutoxide combine with 3 volumes of oxygen ; 
 consequently, as the deutoxide itself consists of 1 vol- 
 ume of nitrogen and 2 of oxygen, nitric acid will by the 
 addition of 3 volumes of oxygen, be composed of 1 volume 
 of nitrogen and 5 of oxygen ; or by weight, of 1 equivalent 
 of nitrogen and 5 of oxygen, as stated at the head of this 
 article. Nitric acid may also be procured from a mixture 
 of nitrogen and oxygen placed over water by passing 
 through it a number of electric sparks, (see the appara- 
 tus, fig. LXXXVII,page 74). 
 
 In a similar manner is nitric acid formed in the atmosphere 
 during a thunder storm ; indices of it having been discovered 
 in rain-water collected immediately after a storm. 
 
 57. Nitric acid formed by art in either manner we 
 have just described , is absorbed by the water over wh ich it is 
 made, by which means it is reduced to the liquid state ; and 
 so great is the affinity of this acid for water, that it is doubt- 
 ful whether it can ever be exhibited in an insolated state. 
 
 58. Liquid nitric odd is an important article of 
 commerce, large quantities of it being used in the arts. 
 For this particular purpose nitric acid is frequently distilled 
 with concentrated sulphuric acid, by which means a most 
 
100 NITROGEN. 
 
 powerful acid is obtained, containing only little more than 
 twentyfive per cent of water ; this being the smallest quan- 
 tity of water with which it is known to exist. The liquid 
 acid is called Hydro-nitric acid, from a Greek word, 
 signifying water. But when this acid combines again 
 with those substances called bases, then the water is given 
 off, and is then said to be in an an-hydrous state. 
 
 59. Properties of Nitric Acid. Nitric acid, or 
 aqua-fortis is a highly corrosive fluid, which oxidates most 
 metals, and, with the exception of tin and antimony, dis- 
 solves them at a gentle heat. Its specific gravity, when 
 most concentrated, is 1.5, that is, it is about half as heavy 
 again as water. It acts as a powerful caustic on the skin, 
 and destroys instantaneously all organized matter. It is 
 decomposed by all substances which have a great affinity 
 for oxygen. When heated, or brought in contact with hy- 
 drogen, it detonates with great violence ; but the experi- 
 ment is somewhat dangerous. When poured upon warm 
 powdered charcoal a combustion takes place, at which the 
 deutoxide of nitrogen is given off in copious fumes. Spir- 
 it of turpentine may likewise be inflamed by it, which 
 may be shown by the following pleasing 
 
 EXPERIMENT. Place some spirit of turpentine, or any 
 
 other essential oil, in a 
 
 Fig. XCIX. warm saucer, and pour 
 
 suddenly some nitric acid 
 upon it. The carbon 
 and hydrogen of which 
 turpentine, and in gene- 
 al all these oils are prin- 
 cipally composed, will 
 unite to combustion with 
 the oxygen of the nitric 
 acid ; and so rapid is the inflammation that it is necessary to pour 
 the nitric acid from a vessel attached to a long stick, in order 
 to avoid the danger to which the eyes of the experimenter 
 would inevitably be exposed if standing too near. 
 
 60. Application of Nitric acid to the arts. Nitric 
 acid is one of the most powerful means of attaining the 
 various ends proposed in chemical investigations, or in the 
 
NITROGEN. 101 
 
 arts. Its great application is founded partly upon its capa- 
 city in union with water to dissolve most solid substances 
 and partly upon the small cohesive attraction between 
 its particles, in consequence of which it is easily decom- 
 posed and yields its oxygen to other substances with 
 which it is brought in contact. To the gold and silver- 
 smith it is a means of separating one metal from an- 
 other. The dyer and cotton printer use it in the prepa- 
 ration of various metallic salts, for the purpose of produc- 
 ing different shades of colors. The artificer in bronze 
 employs its solving power to cleanse the products of his 
 art from various oxides and other impurities ; the engraver 
 uses it in the process of etching ; the turner finds it useful 
 in dying ivory and wood : and so might we continue to 
 transcribe a long catalogue of the useful applications 
 which are made of this acid in the arts, were it not incon- 
 sistent with the limits proposed in this treatise. 
 
 Combination of Nitrogen with Hydrogen Ammonia. 
 
 Chemical composition: 1 equivalent of Nitrogen = 14 
 3 equivalents of hydrogen (each being 1) = 3 
 
 Consequently, Equivalent of Ammonia = 17. 
 
 61. Ammonia, the compound of nitrogen with hy- 
 drogen, is noffound in nature in its free state ; but occurs 
 combined with acids from the mineral and vegetable 
 kingdoms. It is best obtained from a mixture of equal 
 volumes of powdered sal-ammoniac and quicklime, gently 
 heated in a retort. The gas will be given off in great 
 quantities, but must be collected over quicksilver, water 
 absorbing it too fast. When the experiment is made over 
 water, which takes up more than 500 times its own bulk, an 
 aqueous solution of ammoniais formed, which is an article of 
 great use, and possesses all the essential qualities of the gas. 
 
 This solution of ammonia has received the several appella- 
 tions of spirits of sal-ammoniac, spirits of hartshorn, or liquid 
 ammonia, and is extensively employed by druggists. The 
 salt contained -in smelling bottles is a carbonate of ammonia 
 which will be described in the 4th Chapter. 
 
 9* 
 
102 NITROGEN. 
 
 62. Properties of Ammonia. Ammonia is a color- 
 less gas of an extremely pungent smell, and a sharp, burn- 
 ing taste. It changes blue vegetable colors into green, 
 and yellow into brown, and is very much lighter than at- 
 mospheric air, 100 cubic inches of it weighing only 18 
 grains. It is totally irrespirable, and when accidentally 
 taken into the lungs causes cramp and suffocation. An 
 animal plunged into it immediately dies. Neither is it fit 
 to support the process of combustion ; nor is it itself com- 
 bustible in atmospheric air, but in pure oxygen it burns 
 with a yellow flame. It loses its elasticity and becomes 
 liquid at a pressure equal to 195 perpendicular inches of 
 quicksilver, or by a temperature of 40 degrees below 
 zero of Fahrenheit's thermometer. 
 
 From the manner in which we have just stated that ammo- 
 nia affects vegetable colors, and from the remarkable property 
 which it possesses to combine with the acids to salts, it is evi- 
 dent that ammonia belongs to that class of bodies which are 
 called bases (see Intr, page 38). It is therefore called the 
 volatile alkali, to designate its basic nature, and at the same 
 time to distinguish it from the vegetable and mineral alkalis, 
 which are likewise capable of neutralizing the acids and form 
 salts with them. (See Chapter VI.) 
 
 63. When ammonia is passed through narrow red- 
 hot tubes, especially if some iron wire be coiled up in 
 them, it is again decomposed into its elements, nitrogen 
 and hydrogen ; yielding by volume, three times as much 
 hydrogen gas as nitrogen, which proves the correctness of 
 its chemical composition as before stated. It is also de- 
 composed by a series of electric sparks, and when mixed 
 with oxygen may be ignited like a mixture of oxygen and 
 hydrogen. 
 
 Recapitulation of the most important binary combinations 
 of Nitrogen. 
 
 Protoxide of nitrogen. 
 \Deutoxide of nitrogen. 
 
 .Nitric 
 Hydrogen to Ammonia. 
 
CHLORINE. 103 
 
 D. Chlorine. 
 
 Chemical Equivalent = 36. 
 
 64. This is the fourth and last of the gaseous ele- 
 ments which, although not found in its simple state in na- 
 ture, is easily procured in the manner we are about to de- 
 scribe. It is found combined with most of the metals, or 
 united with hydrogen. By art it may either be produced 
 by the action of muriatic acid upon a substance called 
 black oxide of manganese; or it may also be obtained in a 
 cheaper way, by adding 3 parts of finely powdered sea- 
 salt to one part of the same oxide, and pouring upon them 
 in a retort two parts of diluted sulphuric acid. By the 
 application of a gentle heat, chlorine will be given off in 
 great quantities, which may be collected by the pneumatic 
 tub, employing hot water or quicksilver for this purpose ; 
 because cold water absorbs the gas too rapidly. The gas 
 obtained in this manner may be preserved in glass-bottles 
 with greased stoppers, taking great care to expel all water 
 from them. 
 
 65. Properties of Chlorine. Chlorine is a gas of a 
 yellowish green color (whence its name, from a Greek 
 word signifying green), which has an astringent (not acid) 
 taste, and a disagreeable) suffocating smell. When inhal- 
 ed it is exceedingly injurious to the lungs, and may pro- 
 duce instant death. An animal confined in it is almost 
 instantaneously killed. It is not inflammable, but it is 
 capable of supporting the combustion of some substances, 
 such as phosphorus, arsenic, bismuth, antimony, &c. 
 Mixed with vapors of water it becomes liquid, but concen- 
 trates again into a yellow solid substance when surrounded 
 by snow or ice. Its specific gravity is 2.5, that of atmos- 
 pheric air being 1 ; it is consequently two and a half 
 times as heavy as atmospheric air ; 100 cubic inches 
 weighing 76 grains, while the same quantity of air weighs 
 only 30^ grains. Combined with lime it forms chloride 
 of lime, a substance also known by the name of bleaching 
 powder, on account of its possessing the remarkable prop- 
 erty of destroying all animal and vegetable colors. Of 
 
104 CHLORINE. 
 
 this substance we shall speak more fully in the 4th 
 chapter, in treating of the salts. 
 
 Chlorine being specifically heavier than atmospheric air, is 
 one of those gases which may be transferred from one vessel to 
 another without the assistance of the pneumatic tub. Indeed, 
 P. p suppose we had been preparing 
 
 chlorine in the retort A. It 
 would only be necessary to in- 
 troduce a pipe through the cork 
 of this retort to conduct the gas 
 into an open vessel, into which 
 it would descend in consequence 
 of its specific gravity. But chlo- 
 rine collected in this manner 
 combines always with a portion 
 of vapor of water contained in 
 the atmospheric air ; it is there- 
 fore better to collect it over hot water or quicksilver. 
 
 The property of chlorine to support the combustion or to 
 ignite some, of the metals, may be illustrated by the following 
 pleasing 
 
 EXPERIMENT. Fill a long bottle or tube with chlorine, and 
 cover its mouth by a plate of glass. Provide some powdered 
 antimony, which, upon sliding off the cover, pour into the glass. 
 The metal will ignite before it reaches the bottom, and affords 
 a beautiful shower of white flames. Tin, copper, zinc, arse- 
 nic, or even gold introduced in a state of minute division, af- 
 ford the same experiment. 
 
 Combinations of Chlorine ivith Oxygen. 
 
 <, 66. Chlorine combines with oxygen in four different 
 proportions, forming with it two oxides and two acids, 
 viz : Protoxide of Chlorine, Peroxide of Chlorine, Chlo- 
 ric acid, and Perchloric acid. Neither of these com- 
 pounds has ever been found in nature, nor has any appli- 
 cation been made of them in the arts. 
 
 Protoxide of Chlorine 
 
 is composed of 1 equivalent of Chlorine = 36 
 1 do. Oxygen = 8 
 
 Consequently, chemical equiv. of Prot. of Chlorine = 44. 
 It is a deeper colored gas than chlorine ; its smell is 
 
CHLORINE. 105 
 
 somewhat like burnt sugar. It is obtained from heated 
 chlorine of potash mixed with very dilute muriatic acid, 
 and consists, by volume, of 2 volumes of chlorine with 1 
 volume of oxygen. 
 
 Peroxide of Chlorine 
 
 consists of 1 equivalent of chlorine = 36 
 and of 4 equivalents of oxygen (each = 8) = 32 
 
 Chemical equivalent of Peroxide of Chlorine = 68. 
 
 Properties. It is of a yellow color, smells like chlorine, 
 has a very disagreeable astringent taste, and is speedily 
 absorbed by water. It is obtained by the action of sul- 
 phuric acid on chlorate of potash, and is composed, by 
 volume, of 2 volumes of chlorine with 4 volumes of oxygen. 
 
 Chloric acid 
 
 is composed of 1 equivalent of chlorine = 36 
 5 equivalents of oxygen (each = 8) = 40 
 
 Chemical equivalent of Chloric acid =76. 
 
 Properties. It is colorless, always mixed with a small 
 portion of water, consequently liquid, has an astringent 
 taste, and reddens blue vegetable colors. It is obtained 
 from the decomposition of a salt called Chloride of Baryta 
 by means of diluted sulphuric acid, and consists of two 
 volumes of chlorine with 5 volumes of oxygen. 
 
 Per-chloric Acid 
 
 consists probably of 1 equivalent of chlorine = 36 
 8 equivalents of oxygen (each =8) = 64 
 
 Chemical equivalent of Per-chloric acid = 100. 
 
 It is the fourth and last of the combinatians of chlorine 
 with oxygen, and its chemical composition is not precisely 
 known. It is colorless, inodorous, and has a pure sour 
 taste. It consists of 2 volumes of chlorine with v8 volumes 
 of oxygen. 
 
 REMARK. There exists a difference in the opinions of 
 
106 CHLORINE. 
 
 distinguished chemists with regard to the composition of the 
 two compounds, peroxide of chlorine and per-chloric acid. We 
 have stated that the peroxide consists of two volumes of chlo- 
 rine and four volumes of oxygen. This however is doubted, 
 and the composition of this compound stated by some chemists 
 as two volumes of chlorine and three volumes of oxygen. If 
 this be true, its composition is 
 
 1 equivalent of chlorine = 36 
 3 do. of oxygen = 24 
 
 . Chemical equivalent of peroxide of chlorine =60. 
 
 and not 68 as before stated. 
 
 Again, we have stated the chemical equivalent of per- 
 chloric acid to be 100. This substance however, is by some 
 chemists believed to be compounded of 
 
 1 equivalent of chlorine = 36 
 7 equivalents of oxygen = 56 
 
 consequently, chemical equivalent of per-chloric acid =92. 
 Compare this with the remark on page 15. 
 
 Combinations of Chlorine with Hydrogen Muriatic 
 Acid. 
 
 Chemical composition : I equivalent of chlorine = 36 
 1 do of hydrogen = I 
 
 Consequently, Chemical equiv. of muriatic acid = 37. 
 
 67. Chlorine and hydrogen combine together to 
 muriatic acid. This compound is found in nature in form 
 of vapors, or also in a liquid state, particularly in the 
 neighborhood of volcanos, as for instance in the vicinity 
 of Rio Vinagre, in South America. But it may also be 
 obtained by the mysterious influence of solar light. A 
 mixture of hydrogen and oxygen, well secluded from the 
 light, will remain unchanged for any length of time. But 
 if the mixture is made of equal volumes, of these gases and 
 exposed to the light of day (in the shade), they gradually 
 combine without change of volume to a powerful acid, in 
 which the peculiar smell and odor of chlorine will no 
 longer be perceptible. If the mixture be directly exposed 
 to the light of the sun, then the combination takes place 
 suddenly and is attended by an explosion. (The mixture 
 may also be exploded by an electric spark or the flame of 
 
CHLORINE. 107 
 
 a candle). Muriatic acid gas may also be procured in a 
 much cheaper way by the action of strong sulphuric acid 
 on sea-salt. The gas obtained in either way must be 
 collected over mercury, (by the pneumatic tub filled with 
 mercury instead of water) its affinity for water being so 
 great that an unstopped vessel filled with it and placed un- 
 der water, will in a few moments be entirely filled with 
 the liquid, the gas being wholly absorbed. 
 
 68. Properties of Muriatic Acid. It is a colorless 
 gas, of a very pungent smell and strong acid taste. It 
 turns blue vegetable colors into red, and in contact with 
 the atmosphere forms dense white clouds, (in consequence 
 of its combining with the steam or vapor contained in at- 
 mospheric air). By a pressure of about 1120 perpendicu- 
 lar inches of quicksilver (equal to about 40 times trie 
 pressure of our atmosphere) it becomes liquid, but it is 
 neither combustible nor respirable, nor is it capable of 
 supporting the process of combustion. In contact with 
 the oxides it loses its hydrogen, which combines with the 
 oxygen of the oxide to water, setting the chlorine free. 
 This explains the process by which chlorine is obtained 
 from the operation of muriatic acid on black oxide of man- 
 ganese. (See 64, page 103). 
 
 69 When muriatic gas is conducted into water, it 
 is rapidly absorbed by this liquid, by which means liquid 
 muriatic acid is obtained ; a substance similar in prop- 
 erties to the muriatic acid gas, and of great usefulness and 
 application in chemistry and the arts. For this purpose 
 Woulf's apparatus is generally employed. It consists of 
 
 Fig. CI. 
 
 B 
 
108 CHLORINE. 
 
 a number of glass bottles shaped as in figure CI. The 
 bottles A and B, of which there may be any number 
 we please, are each provided with three necks, and con- 
 tain a quantity of water, which is to be impregnated with 
 the gas. When liquid muriatic acid, or as it is sometimes 
 called, hydro-muriatic acid, is to be formed, common salt 
 is put into the retort R, and a small quantity of dilute 
 sulphuric acid poured upon it. When a gentle heat is 
 applied to the retort muriatic acid gas is given off, which 
 passes into the globe G, destined to condense such por- 
 tions of vapor as would render the gas impure. From 
 the globe the gas passes through the bent tube P, into 
 the first bottle A. The water in this bottle will ab- 
 sorb a portion of the gas, and the remainder will pass 
 through the tube Q, into the next bottle, and so on. The 
 bent tubes P, Q,, &c, (see the figure), are a little above 
 the surface of the preceding bottle, and dip below the sur- 
 face of the liquid in the other, in order to allow the gas to 
 escape from one bottle, and to impregnate the water in the 
 other. The process must be carried on until the water 
 in all the bottles is completely saturated. (See Intr. page 
 8). To promote the absorption of the gas, the bottles 
 may be placed in ice. The last bottle must be provided 
 with an open tube to allow the escape of atmospheric air, 
 or such other gas as the water will not absorb. The per- 
 pendicular tubes a, b, are safety tubes, to admit atmos- 
 pheric air into each bottle when the gas ceases to come 
 over from the retort ; for in this case a vacuum would be 
 created in the globe G, (from which the gas is absorbed by 
 the water in the first bottle), into which the pressure of 
 atmospheric air, acting through the open tube S, would 
 force the saturated liquid, which would then be rendered 
 impure, by mixing with the impurities and vapors deposit- 
 ed in G. The liquid muriatic acid thus obtained, possesses 
 all the essential qualities of the gas. 
 
 When prepared on a large scale vessels of iron are 
 
 usually employed instead of glass. This is probably the 
 
 reason why the liquid muriatic acid of commerce contains 
 
 usually a little iron, which gives it a faint yellow tint. 
 
 The applications of muriatic acid are almost as numer- 
 
CHLORINE. 109 
 
 ous as those of nitric acid. It is used in the art of bleach- 
 ing, and is able to dissolve most solid substances, particu- 
 larly metals. It operates very powerfully on metallic ox- 
 ides and forms with some of them (such as oxides of lead 
 or silver) insoluble compounds. Mixed with nitric acid it 
 forms the well known aqua regia* the only liquid which 
 dissolves gold, and is on that account useful to the gold- 
 smith. Combined with oxide of tin. it is used in the 
 processes of dying and calico-printing. It is also employ- 
 ed in the extraction of animal gluten from the bones, for 
 various medicinal purposes. 
 
 Combination of Chlorine ivith Nitrogen. Chloride of 
 Nitrogen. 
 
 Chemical composition : 4 equivalents Chlorine 
 
 (each 36)= 144 
 1 equivalent Nitrogen = 14 
 
 Chemical equivalent of Chloride of Nitrogen = J5S. 
 
 70. This compound of chlorine was discovered by 
 Dulong, a celebrated French chemist. Chlorine and ni- 
 trogen have but a feeble affinity for each other ; but when 
 chlorine is passed through a solution of nitrate of ammo- 
 nia at a temperature of about 90 degrees Fahrenheit, then 
 the chlorine is rapidly absorbed, and an oily film first ap- 
 pears on the surface of the solution, and finally sinks to 
 the bottom of the vessel. This oily liquid is chloride of 
 nitrogen. 
 
 To understand what we have just said, it is necessary to 
 state that nitrate of ammonia is a compound of nitric acid and 
 ammonia, nitric acid being composed of nitrogen and oxygen. 
 The oily globulge which sink to the bottom are formed by the 
 decomposition of the nitrate of ammonia, the nitrogen combin- 
 ing with the chlorine. If a flat vessel be placed at the bottom 
 of the solution, the compound may be collected in it, 
 
 71. Properties of Chloride of Nitrogen. Chloride 
 
 of nitrogen in a yellowish oily liquid, which does not be- 
 
 
 
 * Signifying king's water, because it dissolves gold, which by the 
 alchemist was called the king of metals. 
 
 10 
 
110 RECAPITULATION 
 
 come solid by great degrees of artificial cold. Tts specific 
 gravity is 1.653 that of water being I ; and it is the most 
 powerfully explosive substance known. It should there- 
 fore be handled with great caution, and not be experiment- 
 ed upon in quantities larger than a grain of mustard seed, 
 and even then with great caution.* It explodes at a tem- 
 perature of about 200 degrees Fahrenheit, but detonates 
 in contact with a combustible substance at the common 
 temperature of the atmosphere. A single drop of it 
 thrown into turpentine or olive oil causes so violent an ex- 
 plosion as to burst the phial. 
 
 This phenomenon is explained by the great volume of the 
 two gases, nitrogen and chlorine, which are engaged in the 
 formation of chloride of nitrogen, and which become suddenly 
 free ,and by the expansion of their volume cause the explosion 
 when brought in contact with a combustible substance. 
 
 Recapitulation of the principal binary Combinations of 
 Chlorine, t 
 
 Sr Protoxide of Chlorine. 
 , . Peroxide o Chlorine. 
 
 Hydrogen to Muriatic Acid. 
 Nitrogen to Chloride of Nitrogen. 
 
 RECAPITULATION. 
 
 Questions for reviewing some of the most important Prin- 
 ciples contained in the 1st Chapter. 
 
 A. QUESTIONS ON OXYGEN. 
 
 [ 1.] What are the principal properties of oxygen 1 
 Is the presence of oxygen absolutely indispensable to an- 
 imal life ? 
 
 * See Library of Useful Knowledge. 
 \ See article Chlorides, in Chap. IV . 
 
OF CHAPTER I. Ill 
 
 [ 2.] Describe some of the ways in which oxygen is 
 obtained. 
 
 [ 3.J What is that process called, by which oxygen 
 combines with other simple and compound bodies'? 
 
 [ 4.] How many different names are given to the ox- 
 ides ? To what substance is the name of Protoxide given ? 
 What is a Deutoxidc ? What a Peroxide ? By what 
 means do we distinguish between the names of the differ- 
 ent acids ? What does the name of the acid in ic indicate ? 
 What that, terminating in ous 1 What does the name of 
 hypo signify when put before the name of an acid ? 
 
 Give examples. 
 
 [ 5.] In what consists the combustion or burning of 
 bodies ? What is every body called which is capable of 
 such a combination with oxygen ? 
 
 What was the phlogiston of the ancients ? 
 
 [ 6.] What do most bodies require for their combus- 
 tion 1 Give examples. 
 
 Explain the process of a burning lamp or candle. 
 
 [ 7.] Is the light which is given out during the pro- 
 cess of combustion always the same, or is it subject to va- 
 riation in intensity and color ? 
 
 Give examples. 
 
 [ 8.] How do all bodies burn in oxygen ? 
 
 Give examples. (Explain Figs. LXIV, LXV, LXVI.) 
 
 What do these examples prove with regard to the heat pro- 
 duced by combustions in pure oxygen ? 
 
 [ 9.] When the whole product of combustion is 
 weighed, is it found heavier or lighter than the substance 
 was before the combustion 1 Give an example. 
 
 But why do the ashes produced by burning wood or straw 
 weigh less than the wood or straw before the combustion ? 
 When the inflammable gas which is given off during the 
 combustion of these substances is collected, and its weight 
 added to that of the ashes, is the sum of their weight 
 greater or less than that of the wood or straw before the 
 combustion ? 
 
112 RECAPITULATION 
 
 [ 10.] Can any combustion take place without the 
 presence of oxygen ? How long therefore can the com- 
 bustion of oxygen only be continued ? 
 
 What experiment can you describe to prove your assertion r 
 (Explain Fig. LX VII). What alteration will take place, if in 
 your experiment, you employ atmospheric air instead of pure 
 oxygen? What does the slower burning of the candle in 
 common atmospheric air prove ? Why does the water rise 
 higher in the receiver when pure oxygen is used ? Why does 
 the candle become extinguished when 21 per cent of the 
 whole air contained in the receiver, are consumed? What is 
 required for a complete combustion of bodies in oxygen or at- 
 mospheric air? (Explain Pig. LXVIII). What remarkable 
 coincidence is there between the processes of respiration 
 and combustion ? 
 
 [ 11.] By what is the quantity of air necessary for 
 combustion, supplied ? What do you call a draft? For 
 what purpose are fire-places and chimneys built? 
 
 How are smoking fire-places improved ? Why is the flame 
 of an Argand's lamp brighter than that of a common lamp ? 
 
 [ 12.] How is fire extinguished ? By what means is 
 this effected ? 
 
 Why are small quantities of water of little use in the extin- 
 guishing of conflagrations ? 
 
 [ 13.] Is the combination of oxygen with other sub- 
 stances always accompanied by the phenomenon of fire ? 
 In what cases is it not ? 
 
 Give instances of such combinations. 
 
 [ 14.] In what does the process of desoxidation 
 consist ? In how many different ways is it effected ? What 
 are they ? 
 
 B. QUESTIONS ON HYDROGEN. 
 
 [ 15.] What becomes of water when subjected to 
 the action of galvanic electricity ? Explain Figs. LXIX, 
 LXX, and LXXI. What is most remarkable about this 
 decomposition of water ? 
 
OFCHAPTERI. 113 
 
 [ 16.] What are the characterizing properties of 
 hydrogen ? 
 
 Explain the two experiments represented in Figs. LXXII, 
 and LXXIII (page 62). In what manner can hydrogen gas be 
 transferred from one vessel to another ? Explain the experi- 
 ment represented in Fig. LXXIV. 
 
 By what experiment can you show the levity of hydrogen 
 gas ? Explain Fig. LXXV. How does the experiment you 
 have just described enable us to find the specific gravity of 
 hydrogen ?* Describe the experiment represented in fig. 
 LXX VI, which shows the levity and combustibility of hydrogen. 
 
 [ 17.] Is galvanic electricity the only means of ob- 
 taining hydrogen gas? What other means have we for 
 procuring this gas 1 (Explain Figs. LXXVII, and 
 LXXVIII.) 
 
 [ 18.] How is the great levity of hydrogen gas taken 
 advantage of? (Explain Fig. LXXIX). In what con- 
 sists the construction of balloons for ascending in the air ? 
 (Explain Fig. LXXX). 
 
 [ 19.] In what proportions may oxygen be mixed 
 with hydrogen ? Is there a strong affinity between the 
 substances ? 
 
 By what experiment can you prove this ? Explain the ex- 
 periment represented in Fig. LXXXt. In what manner does 
 Prof. Schubert account for the explosion accompanying the 
 combustion of inflammable air ? 
 
 [ 20.] What is formed when one volume of hydro- 
 gen gas is mixed with two volumes of atmospheric air ? 
 
 Explain Fig. LXXXII. Explain the experiment represented 
 in Fig. LXXXIII. 
 
 [ 21.] What is the most important application made 
 of the properties of inflammable air to various chemical 
 purposes ? Explain Fig. LXXXIV. What are the effects 
 of Dr Hare's compound blow-pipe ? 
 
 [ 22.] What is the construction of the blow-pipe 
 
 * This question need not be put to very young pupils. 
 10* 
 
114 RECAPITULATION 
 
 with condensed oxygen and hydrogen 1 Explain Fig. 
 LXXXV. How is the apparatus used ? 
 
 [ 23.] Describe the experiment (represented in Fig. 
 LXXXVI) by which water is formed by the combustion 
 of hydrogen ? What inference do you draw from this 
 experiment with regard to the nature of water 1 
 
 [ 24.] In what proportion do hydrogen and oxygen 
 combine to water? By what experiment can you prove 
 that water consists of two volumes of hydrogen combined 
 with one volume of oxygen 1 Explain Fig. LXXXVII. 
 What does this experiment serve to establish 1 
 
 [ 25.] Of how many equivalents of hydrogen and 
 oxygen does water consist ? What is the equivalent num- 
 ber of oxygen? What, that of hydrogen ? What, there- 
 fore that of water ? 
 
 [ 26.] What remarkable law has been discovered in 
 reference to the combinations of the gases ? 
 
 [ 27.] What are the most essential properties of wa- 
 ter? What is the weight of a cubic inch of distilled wa- 
 ter ? At what degree of Fahrenheit's scale is the greatest 
 density of water? What is the condensation of oxygen 
 and hydrogen in the act of forming water. 
 
 How does the sudden diminution in the volume of the 
 two gases account for the heat given out during the combus- 
 tion of hydrogen ? 
 
 What influence has this peculiarity of water te be most 
 dense at 40 degrees Fahrenheit have upon the economy of 
 nature ? What would become of the waters in the northern 
 regions, if water did not possess this property ? 
 
 [ 28.] Does water in the act of freezing or congeal- 
 ing expand or contract in volume ? What phenomena 
 does this explain ? What is the specific gravity of ice ? 
 What is this the reason of ? 
 
 [ 29.] Which of the three kinds of water, rain, riv- 
 er, or pump water, is the purest ? Why ? Which comes 
 next to it ? What are the first two kinds called in oppo- 
 sition to pump water ? What does pump water always 
 
OF CHAPTER I. 115 
 
 contain? What are the ingredients of mineral waters'? 
 What are the principal salts contained in sea-water? 
 
 [ 30.] What do all kinds of water contain ? Do 
 they contain atmospheric air as a chemical ingredient, or 
 merely mechanically entangled? By what means may 
 water be freed from it ? 
 
 [$ 31.] Is water a good conductor of heat? What 
 experiment convinces us that water is a bad conductor of 
 heat? 
 
 Describe the experiment represented in Fig. LXXXVIII. 
 Explain the experiment repieseuted in Fig. LXXXIX. 
 
 Could water be heated without the mobility of its particles? 
 Why not? What then, is the reason why burning ether on 
 the surface of water does not affect a small thermometer im- 
 mersed in the water ? 
 
 [ 32.] Does the pressure of the atmosphere or of 
 steam promote or hinder the boiling of water and other 
 liquids ? What is this the reason of? How can this be 
 illustrated ? (Describe the experiment represented in the 
 XCth figure). 
 
 What does this experiment prove? What inference can 
 you draw from the experiment just described, with regard to 
 the boiling of water or other liquids ? 
 
 [ 33.] What does water constantly absorb ? Into 
 what does it thereby become converted ? Of what use is 
 the absorption of heat or caloric by the large waters on 
 the surface of our globe ? What is the continued forma- 
 tion of vapors from the surface of water called ? What do 
 the vapors of water contained in the atmosphere, form ? 
 what becomes of these, when brought in contact with cold- 
 er strata of air ? 
 
 By what experiment may the refrigerating influence of 
 forming vapors of liquids be illustrated ? Describe the exper- 
 iment represented in Fig. XCI. 
 
 What other illustration is there of the cold produced by 
 the rapid process of evaporation ? 
 
 Describe Dr Wallaston's Cryopborus or Frost-bearer, and 
 its operation. By what other natural processes are the effects 
 of evaporation happily illustrated ? How does the process of 
 
116 RECAPITULATION 
 
 evaporation operate upon the human body? Why is it dan- 
 gerous to be exposed to a current of cold air when the clothes 
 have become moist with perspiration ? 
 
 [ 34.] What is necessary to obtain water in its pure 
 state ? By what process may small quantities of water 
 be distilled? (Explain Fig. XCIII). What properties 
 does the water thus obtained possess ? 
 
 [ 35.] What becomes of all the heat or caloric that 
 is added to boiling water ? What is steam which is shut 
 up in a vessel capable of exercising ? To how many 
 times its volume may water thus be expanded ? 
 
 By what experiment may the principal properties of steam 
 be illustrated ? Describe the experiment represented in fig. 
 XCIV. Why is the piston in your experiment driven down 
 when the tube is plunged into cold water ? and why is the 
 piston moved up again, when the bulb of the tube is again 
 held over the flame of the lamp ? What is the cause of the 
 power and operation of the steam-engine ? 
 
 [ 36.] What properties must chemically pure water 
 possess? When it is only necessary to know the propor- 
 tion which the solid substances, dissolved or contained in 
 water, bear to the whole volume of the liquid, by what 
 means may this be ascertained ? 
 
 [ 37.] Is water the only compound of oxygen and 
 hydrogen 1 What other combination is there of the same 
 elements ? What is the name of this compound ? 
 
 [ 38.] What are the principal properties of oxygen- 
 ized water 1 
 
 Recapitulate the binary combinations of hydrogen and 
 oxygen. 
 
 C. QUESTIONS ON NITROGEN. 
 
 [ 39.] What sort of gas is Nitrogen, and what are 
 its principal properties ? 
 
 Why has this gas been called Azote ? Is this expression 
 correct? Why not? 
 
OF CHAPTER 1. 117 
 
 [ 40.] By what means may nitrogen be easiest ob- 
 tained ? How is nitrogen separated from oxygen 1 
 
 [ 41.] What particular mixture of Nitrogen and 
 Oxygen resembles, or constitutes our atmosphere ? 
 
 How do we know that nitrogen and oxygen are actually 
 contained in the atmosphere in the proportion of 4 volumes 
 of nitrogen to 1 volume of oxygen. 
 
 [ 42.] Are nitrogen and oxygen the only ingredients 
 of atmospheric air? What other substances are yet con- 
 tained in it 1 Upon what does the quantity of vapor de- 
 pend 1 Is the proportion of carbonic acid greater in sum- 
 mer or in winter 1 in the night or in day-time. 
 
 What are the exact proportions, by weight, of nitrogen, 
 oxygen, and carbonic acid gas contained in our atmosphere, 
 abstracting for a moment from the variable quantity of vapor? 
 
 [ 43.] Is the proportion of the principal ingredients 
 of our atmosphere, nitrogen and oxygen, variable 1 
 
 At what result did Gay Lussac arrive from examining the 
 air at a height of 24,600 feet above the level of the sea, and 
 that of crowded theatres in Paris ? 
 
 Has any other mixture of gases been found capable to sup- 
 port the process of respiration and animal life as well as at- 
 mospheric air ? What would be the probable consequence if 
 the air did contain more nitrogen or less oxygen? What, on 
 the contrary, would take place if the quantity of nitrogen be 
 diminished, or that of oxygen increased ? 
 
 [ 44.] What accidental ingredients are yet contained 
 in the atmosphere, besides those you have already enumer- 
 ated ? 
 
 [ 45.] What is the object of Eudiometry ? W T hat 
 substance will answer this purpose ? What is an appara- 
 tus constructed for this purpose called 1 Explain the con- 
 struction of Achard's Eudiometer (Fig. XCV.) Of what 
 consists Volta's Eudiometer for detonating oxygen and hy- 
 drogen gas 1 (Explain Fig. XCVI). What other Eudi- 
 ometer may be used for this purpose instead of the ojne 
 you have just described ? 
 
 By what means, in the experiment you have now described, 
 
118 RECAPITULATION 
 
 are you able to find the volume of oxygen contained in atmos- 
 pheric air? 
 
 Upon what principle is Gay Lussac's eudiometer con- 
 structed ? Of what does it consist ? How is it to be 
 used? 
 
 What fact has been established by the various experiments 
 which have been made with Eudiometers? Can the great 
 difference which exists between the air of certain places, and 
 at different times, be explained from the greater or less quan- 
 tity of oxygen contained in it ? Do we know anything about 
 the different miasmas which, at times, are contained in the at- 
 mosphere ? 
 
 [ 46.] In how many different proportions does nitro- 
 gen combine with oxygen ? What are the products of 
 these combinations 1 
 
 [ 47.] What is the chemical composition of protox- 
 ide of nitrogen ? Is it a product of nature or of art ? 
 How is it best and easiest obtained 1 (Explain the exper- 
 iment represented in Fig. XCVIII). 
 
 [ 48.] What are the characterizing properties of 
 protoxide of nitrogen. 
 
 What is the average quantity of this gas that can be inhaled 
 without being injurious to the lungs ? 
 
 What influence has electricity upon the Protoxide of 
 nitrogen ? What becomes of this gas when mixed with 
 hydrogen, and an electric spark is applied to it T 
 
 (The remainder of this section it is sufficient for the pupil to 
 understand. More advanced pupils may repeat the reasoning.) 
 
 [ 49.] What is the chemical composition of Deutoxide 
 of Nitrogen 1 By what means is it obtained ? How is 
 this process explained ? 
 
 [ 50.] What are the principal properties of deutoxide 
 of nitrogen ? What takes place when deutoxide of nitro- 
 gen is mixed with oxygen and the experiment is made over 
 water? What takes place if, instead of oxygen, atmos- 
 pheric air is employed ? 
 
 What instrument is founded upon the property of the deu- 
 toxide of nitrogen to absorb the oxygen from atmospheric air ? 
 
OF CHAPTER I. 119 
 
 How then do you use the apparatus described on page 92, Fig. 
 XCVII ? 
 
 [ 51.] By what means may deutoxide of nitrogen be 
 decomposed ? 
 
 [$ 52.] What is the supposed chemical composition of 
 Hypo-nitrous acid? In what manner is it generated? 
 What do some chemists pretend, as regards its appearance 
 at common temperatures? 
 
 [ 53.] What is the chemical composition of nitrous 
 acid ? In what way may it be produced ? 
 
 [ 54.] What, remark can you make respecting the 
 different combinations of oxygen and nitrogen by volumes? 
 What general law does this verify ? 
 
 [ 55.] What are the properties of nitrous acid ? 
 
 [ 56.] What is the chemical composition of nitric 
 acid ? Where is nitric acid found in nature ? In what 
 way is it obtained by art? By what other means may it 
 be procured ? 
 
 How is nitric acid produced in the atmosphere ? 
 
 [ 57.) Is nitric acid, found in either way you have 
 just described, obtained in a gaseous or liquid state ? 
 
 [ 58.] In what manner is liquid nitric acid prepared 
 for commerce ? What is the smallest quantity of water 
 with which 1 it is known to exist? What is the liquid 
 nitric acid sometimes called ? When is nitric acid said to 
 be in an an-hydrous state ? 
 
 [$ 59.] What are the characterizing properties of 
 nitric acid ? What is its specific gravity ? How does it 
 act upon the skin and all organized matter ? What takes 
 place when nitric acid is brought in contact with hydro- 
 gen ? What when poured upon warm powdered charcoal ? 
 How does it affect spirit of turpentine or any other essential 
 oil? (Explain the experiment represented in Fig. XCIX.) 
 
 [ 60.] What applications are made of this acid in 
 the arts ? 
 
120 RECAPITULATION 
 
 [ 61.] What is the chemical composition of Ammo- 
 nia? Where does ammonia occur ? How is it best ob- 
 tained ? What is formed when the experiment is made 
 over water ? 
 
 What is the aqueous solution of ammonia called ? What 
 does the salt contained in smelling-bottles consist of? 
 
 [ 62.] What are the principal properties of ammonia? 
 To what class of bodies does ammonia belong ? What is it 
 therefore called ? 
 
 [^ 63.] What takes place when ammonia is passed 
 through red-hot tubes (particularly if some iron wire be 
 coiled up in them) ? 
 
 What are the most important binary combinations of 
 nitrogen ? 
 
 D. QUESTIONS ON CHLORINE. 
 
 [ 64.] In what state is chlorine found in nature? 
 How may it be produced by art ? 
 
 [ 65 ] What are the characterizing properties of 
 chlorine ? 
 
 In what manner can chlorine be transferred from one vessel 
 to another ? (Explain Fig. C.) W T hat other experiment can 
 be made to show the property of chlorine to support combus- 
 tion and to ignite some of the metals ? 
 
 [ G6.] In how many different proportions does chlo- 
 rine combine with oxygen ? What are the compounds ? 
 Has any of these compounds been found in nature in its 
 simple state ? What is the composition of protoxide of 
 chlorine ? What sort of gas is it ? 
 
 What is the composition of the peroxide of chlorine ? 
 What are its properties ? 
 
 What is the composition of chloric acid ? What are its 
 properties ? 
 
 What is the composition of per-chloric acid ? What are 
 its properties ? 
 
 [ 67.] What is the name of the compound formed by 
 the combination of chlorine with hydrogen ? Where is 
 
OF CHAPTER 1. 121 
 
 this compound found 1 What is the composition of mu- 
 riatic acid ? By what influence is it obtained ? In what 
 other way may muriatic acid gas be obtained ? 
 
 [ 63.] What are the principal properties of muriatic 
 acid 1 What does muriatic acid lose in contact with the 
 oxides of metals ? 
 
 [ 69.] What takes place when muriatic acid gas is 
 conducted into water ? What apparatus is generally em- 
 ployed for this purpose ? (Describe the apparatus repre- 
 sented in Fig. CI.) 
 
 What sort of vessels are employed when liquid muriatic 
 acid is prepared on a large scale ? What is this the 
 cause of? 
 
 Are any applications of this acid made in the arts I 
 What are they ? 
 
 [ 70.] To what compound does chlorine combine 
 with nitrogen 1 What is the composition of this com- 
 pound ? By what process is it formed ? 
 
 [ 71.] What are the properties of chloride of nitro- 
 gen ? How is its great explosive power explained ? 
 
 What are the principal binary combinations of Chlorine ? 
 
 11 
 
122 CARBON 
 
 CHAPTER II. 
 
 OP THE REMAINING NINE NON-METALLIC ELEMENTS, AND 
 
 THEIR COMBINATIONS. 
 
 72. Besides the four gases, Oxygen, Hydrogen, 
 Nitrogen and Chlorine, there are yet nine other non-me- 
 tallic elements which, with the exception of Boron, are all 
 solid at the mean temperature of the atmosphere. Their 
 names are Carbon, Sulphur, Selenium, Phosphorus, Boron, 
 Iodine, Bromine, Silicon, and Fluor. They are, like the 
 gases, bad conductors of electricity and heat,* and become 
 all converted into vapor by the application of a gentle 
 heat. 
 
 A. Carbon. 
 
 Chemical Equivalent = 6. 
 
 73. Properties of Carbon. Carbon occurs in nature 
 as the principal ingredient of coal. It is either found in 
 its pure state as diamond ; or mixed with earthy mass- 
 es in graphit, anthracite coal, turf, &c, and enters 
 largely into the composition of all animal and vegetable 
 substances. 
 
 Diamonds are chiefly found in the East Indies, (in the mines 
 of Golconda) and in Brazil, (in the Province of Serro do Frio). 
 They are generally disseminated in sand or gravel, and fre- 
 quently mixed with gold. They are considered gems of the 
 highest value. They are found either crystallized (in form of 
 
 * Carbon is a pretty good conductor of both. 
 
CARBON. 123 
 
 octahedrons*) or in grains. They are either colorless, (and are 
 then said to be of the first water) or of a light red, green, blue, 
 and even black color. Diamond is the hardest substance 
 known. Its specific gravity is 3.5*2. When submitted to the 
 action of heat in close vessels its properties do not change; 
 but in the focus of a large burning-glass, or in pure oxygen it 
 is entirely consumed. The product of the combustion, car- 
 bonic acid gas, is precisely the same as that obtained from 
 burning charcoal. 
 
 Graphit or Plumbago is of a grayish black color (like iron or 
 steel). It is opaque, and has a black, metallic lustre. It re- 
 sists the action of a common fire, but is consumed by higher 
 degrees of heat, or by the effect of a voltaic battery. It is a 
 compound of carbon and about 4 per cent of iron. Extensive 
 use is made of plumbago in the manufacture of lead-pencils. 
 It is also used in the making of crucibles for the use of gold 
 and silver-smiths. Mixed with fat it a most excellent means 
 to prevent friction in wagons, mills, and other machines. 
 
 Anthracite Coal. Anthracite Coal (glance-coal of the Eng- 
 lish) occurs in irregular forms. Great quantities of it are 
 found in Pennsylvania, and will probably be discovered in oth- 
 er parts of the United States. It is opaque, of a greyish- 
 black color, is rather difficult to kindle, burns without much 
 flame or smoke, and leaves for ashes a mixture of silicious 
 earth, mixed with clay and oxide of iron. 
 
 Lehigh Coal. Lehigk Coal has a strong, metallic lustre, 
 and leaves when burnt 13J per cent white ashes. Although 
 difficult to kindle, it is extensively used in America. 
 
 Black and Brown Coal. Black and Brown Coal is found 
 in England Scotland,f and Germany.! When burnt it oc- 
 casions a disagreeable smell, owing to the oily substances 
 which it contains, and which are given off during combustion. 
 It leaves, however, but 3 per cent of ashes. - 
 
 Turf. Turf is a tissue of vegetable substances, reduced 
 to a compact solid, by a peculiar process of decomposition. 
 When slowly burnt it produces from 26 to 28 per cent of coaZ, 
 but leaves a great deal of ashes. 
 
 Vegetable Charcoal is obtained by burning wood, which pro- 
 
 * See Grand's Solid Geometry, Appendix. 
 
 t New-Castle, Whitehaven,Dumfrieshire, Derbyshire, Sheffield, 
 Clydesdale, &c. 
 
 | Silesia, Westphalia, Saxony, Wurtemberg, and Bavaria. 
 
124 CARBON. 
 
 cess, however, must be carefully conducted. It is used as 
 fuel in cupelling furnaces ; as a principal ingredient in the 
 manufactory of powder (see Chap. IV), and as a dyeing 
 stuff in the manufactory of blacking. It has the peculiar 
 property of resisting the putrefaction of animal substances, 
 (and may therefore be used for the preservation of meat) ; but 
 it destroys their color and smell. It is also a great purifyer of 
 water, and is on this account used extensively in the refining 
 of sugar. But the most remarkable property of charcoal con- 
 sists in its power of resisting destruction. This property 
 of charcoal was even known to the ancients, who were in 
 the habit of charring their piles and posts (burning their sur- 
 faces to coal) before driving them into the ground ; and so 
 well has this preserved them from decay, that when the piles 
 upon which the foundation of the temple of Ephesus rested, 
 were but of late taken from the ground, the charcoal upon 
 their surface appeared perfectly fresh, and the wood under- 
 neath free from rot or putrefaction. Charcoal is also unalter- 
 able by heat, if excluded from atmospheric air; but in contact 
 with other substances exercises a powerful influence upon 
 them by combining with the oxygen which enters into their 
 chemical composition. Its mechanical structure (its inter- 
 stices, or pores) enable it to absorb large quantities of gases, 
 and it is known in one instance to retain more than 90 times 
 its own volume. 
 
 Animal Charcoal (bone-black) is obtained from burning an- 
 imal substances, commonly bones, horns, &c. It is of a deep 
 black color, and is used in the manufactory of printers' ink. 
 
 REMARK. Although carbon abounds in all the three king- 
 doms of nature, it is rarely found in its pure state as diamond. 
 All attempts to procure diamonds by art, or, in other words, to 
 extract pure solid carbon from other substances, have hitherto 
 proved ineffectual. 
 
 Quen/ Why is charcoal so different in appearance from 
 diamond, one being black and opaque, the other transparent, 
 brilliant, and the hardest substance known ? Jlns. Because 
 diamond is Carbon in its pure, crystallized state, and the other 
 is mixed with various impurities, and other constituents, adding 
 sometimes more than 10 or 20 per cent to its amount of pure 
 carbon. Ques. But why has it thus far been impossible for 
 us to crystallize carbon, or to make diamonds, as we are able 
 to produce water from the union of its ingredients, hydrogen 
 and oxygen? Jlns. The probable reason is that diamond 
 is of organic formation as the similarity of its chemical com- 
 
CARBON. 125 
 
 position to charcoal plainly indicates ; and that if this be true, 
 we might as well wish to create plants and animals, because 
 we know their chemical composition, which would evidently 
 be impossible. 
 
 Combinations of Carbon with Oxygen. 
 
 74. Carbon combines with oxygen in 5 different 
 proportions ; but of the compounds thus formed there are 
 but two which deserve special notice, or which are of any 
 application in common life. These are carbonic oxide, 
 and carbonic acid. 
 
 Carbonic Oxide 
 
 consists of 1 equivalent of Carbon = 6 
 and 1 equivalent of Oxygen = 8 
 
 Consequently, chem. equiv. of Carbonic Oxide = 14 
 
 75. This compound does not occur in nature ; but 
 is easily produced by art, by applying heat to a mixture of 
 charcoal and lime, or by heating two parts of chalk and 
 one of iron-filings in a gun-barrel, and collecting the gas 
 which is given off in the usual manner. 
 
 Both processes are easily explained. In the first instance, 
 the vapors of carbon produced by the charcoal, combine with 
 the oxygen of the lime (which, as we shall see, is a combination 
 of oxygen with calcium). In the second case, when lime 
 or chalk are heated, carbonic acid is formed (see the next 
 section), which, when the iron is heated, yields again a portion 
 of it Jo this metal ; by which means it becomes reduced to car- 
 bonic oxide. 
 
 76. Properties of Carbonic Oxide. It is a gaseous, 
 colorless substance, which in its pure state is without taste 
 or smell. It is incapable of supporting the process of com- 
 bustion, but is itself inflammable and burns with a blue 
 flame. When taken into the lungs it causes giddiness, 
 stupor, and fainting, even when mixed with 25 per cent 
 of atmospheric air. 
 
 n* 
 
126 
 
 C A R B ON . 
 
 Carbonic Acid (Fixed Air.) 
 
 Chemical composition: 1 equivalent Carbon = 6 
 2 equivalents Oxygen (each 8) = 16 
 
 Consequently, chem. equivalent of Carbonic acid = 22. 
 
 77. Carbonic acid gas is always contained in small 
 quantities in the atmosphere ; particularly in the neigh- 
 borhood of volcanos ; (near mount Vesuvius, in the cave 
 of Pausilippo, near Puzzuoli, in Pyrmont, &c). It is 
 continually produced by the burning of wood or coal, by 
 the respiration of men and animals (see chapter Vll), and 
 by every process of fermentation and putrefaction which 
 takes place in nature. It is also found in coal mines, 
 where it occasions the chalk dampness of the miners, which 
 in many instances has proved fatal to them. By art it may 
 be produced by dropping fragments of marble or chalk 
 into dilute muriatic or sulphuric acid. 
 
 Marble and chalk are compounds of carbonic acid with 
 an oxide of a metal called oxide of calcium, and are com- 
 posed of about 22 parts of carbonic acid with 28 parts of 
 lime. When exposed to the action of sulphuric or mu- 
 riatic acid, which have a strong affinity for the lime, this 
 substance combines by elective affinity with the acid, set- 
 ting the carbonic acid free. 
 Fig. OIL 
 
 For the purpose of 
 making the experi- 
 ment, introduce some 
 pure white marble in 
 small fragments into 
 a two-necked bottle 6, 
 shaped like that repre- 
 sented in the adjoining 
 figure, CII. Upon 
 these, through the fun- 
 nel n, pour some dilute 
 sulphuric acid ; when 
 a quick effervescence will take place, by which carbonic 
 is given off in abundance, which may be conducted 
 
CARBON. 127 
 
 through the pipe P, through the pneumatic tub into the 
 receiver R. 
 
 Query By what kind of affinity is the carbonic acid, in 
 this experiment, formed ? Ans. By single elective affinity. 
 Ques. Why ? Jins. Because marble is a carbonate of 
 lime, consisting of a combination of carbonic acid with oxide of 
 calcium (seethe last section); but when sulphuric acid is 
 added, for which the oxide of calcium has a stronger affinity 
 than for carbonic acid, then the oxide quits its combination 
 with the carbonic acid and elects as it were, in preference, a 
 combination with the sulphuric acid, setting the carbonic acid 
 free. This is the cause of the effervescence which takes place 
 when dilute sulphuric acid is poured upon fragments of marble 
 or chalk. 
 
 78. Properties of Carbonic Add. Carbonic acid 
 or as it is commonly called, fixed air, is a combination 
 of equal volumes of carbon and oxygen. It is a perfectly 
 colorless gas, which has a pungent, half acid taste, and is 
 not inflammable. A burning taper immersed in it is 
 instantly extinguished. When taken into the lungs it 
 proves speedily fatal to life. It is so extremely poisonous 
 that but a small quantity of it, even mixed with atmos- 
 pheric air is sufficient to produce dimness, difficulty of 
 respiration, swoon, apoplexy, and death. Hence the dan- 
 ger arising from burning charcoal in a room that is not 
 well ventilated ; because during combustion a considera- 
 ble quantity of this gas is given off. 
 
 The danger of burning charcoal in a confined room is two- 
 fold. 1st. 'From the fact that during the process of combus- 
 tion a considerable quantity of oxygen is consumed, which, 
 if no draft be created to supply fresh quantities of it, must 
 finally terminate in a complete exhaustion of that principle 
 which alone can support animal life. 2d. By the combination 
 of oxygen with charcoal a considerable quantity of carbonic 
 acid is formed, which from the stupor and swoon which it 
 causes, deprives the person thus exposed to its injurious influ- 
 ence, soon of the means of rescuing himself from this deadly 
 poison. It is needless to dwell on the many fatal accidents 
 that have occurred either from ignorance, or from a disregard 
 of this property of carbonic acid. 
 
128 CARBON. 
 
 79. Carbonic acid gas is quickly absorbed by water 
 and other liquids. In this manner (mechanically entan- 
 gled between the particles of liquids) it is contained in a 
 variety of mineral waters, and in all sparkling, ferment- 
 ing liquors, such as beer, cider, champaigne, &c, causing 
 that agreeable pungent taste, which these liquids lose 
 after being for some time exposed to the atmosphere. 
 Our common Soda and Seltzer waters are charged with 
 carbonic acid by means of forcing pumps. The pleasant 
 fresh taste of common pump water is in a great meas- 
 ure owing to the carbonic acid which collects at the bottom 
 of the wells. From river water the carbonic acid is con- 
 tinually absorbed by the atmosphere. This constitutes 
 the principal difference between hard and soft water (see 
 Chapter I, 29, page 71). 
 
 This is a striking instance of the various properties of gases 
 and their several adaptations to our convenience and comfort. 
 Thus carbonic acid, though perfectly irrespirable, and poison- 
 ous and destructive to life when taken into the lungs, may 
 with impunity be taken into the stomach, and is one of the 
 most efficient and agreeable means of refreshing ourselves 
 when overcome by the heat of summer. But what is still 
 more interesting in this gas, is the contrast between its prop- 
 erties, and those of the elements from which it is derived. 
 Carbon, which in the form of charcoal may be taken into 
 the stomach in a considerable quantity without being in- 
 jurious, and whose presence in a dormitory is no more dan- 
 gerous than atmospheric air itself; when combined with oxy- 
 gen, an element without which life would instantly cease, and 
 which may therefore be considered the very supporter of it, 
 forms a poison which may destroy life in a very few minutes ! 
 And this very poison, when taken into the mouth and stomach, 
 produces no other effect than an agreeable, gentle coolness 
 which is perfectly healthy and palatable ! 
 
CARBON. 
 
 129 
 
 Fig. CII1. 
 
 Before Seltzer and soda waters became as 
 common as they are now, Nooth's apparatus 
 was used for impregnating water or any other 
 liquid with carbonic acid. Fig. CHI shows 
 its construction and use. It consists of a 
 vessel A, destined to hold some pulverized 
 marble or chalk, upon which, through the 
 opening 6, may be poured some dilute sul- 
 phuric acid. The carbonic acid gas which is 
 thus generated ascends through the valve a, 
 into the second vessel B, filled with the 
 liquid, which is to be impregnated with it. 
 The valve a, is so constructed that it admits 
 the carbonic acid into the vessel B, but pre- 
 vents the liquid in that vessel from descend- 
 ing into A. The uppermost vessel C, is 
 destined to receive the water which is dis- 
 placed from the vessel B, by the rise of the 
 gas. When the liquid in B, is sufficiently 
 
 charged with the gas, it may be drawn off by means of the 
 
 discharging cock D. 
 
 80. It has been mentioned in 36, page 85, as one 
 of the criterions of pure water, that mixed with lime-wa- 
 ter it must not become turbid, otherwise it contains car- 
 bonic acid. The reason of this is now easily understood. 
 When lime-water is poured into water which contains 
 carbonic acid, this substance combines immediately with 
 the lime to an insoluble compound, called carbonate of 
 lime, which is at first seen in form of white clouds and 
 afterwards sinks to the bottom. 
 
 hy 
 
 Combination of Carbon with Hydrogen. 
 
 81. Carbon unites in two different proportions with 
 rogen. The products of these combinations are two 
 
 permanently elastic gases Sub-carburetted Hydrogen, 
 and Carburetted Hydrogen. 
 
130 
 
 CARBON. 
 
 Sub-carburetted Hydrogen 
 
 is composed of 1 equivalent of Carbon = 6 
 and 2 equivalents of Hydrogen (each being 1) = 2 
 
 Consequently, chemical equivalent of sub-carbu- 
 
 retted Hydrogen = 8. 
 
 82. This gas, which is also called light Carburetted 
 hydrogen, or heavy inflammable air, is formed wherever or- 
 ganic matter putrefies, in pools, swamps, and stagnant wa- 
 ters. It is also found in coal mines (the fire-damp of the 
 miners), where by its dreadful explosion it proved frequent- 
 ly fatal to the workmen. (Disasters of this kind have 
 since been obviated by Sir Humphrey Davy's safety lamp, 
 for the description of which see the next section.) 
 Fig. CIV. 
 
 It may be readily procured 
 by stirring the bottom of pools 
 or stagnant water, and collect- 
 ing the gas which rises in little 
 bubbles with an inverted bottle, 
 which for this purpose ought 
 to be provided with a funnel, 
 (see the adjoining figure, CIV), 
 
 83. Properties of sub-carbitretted hydrogen. It is 
 a colorless gas which is highly inflammable, and burns 
 with a yellowish blue flame, giving out considerably more 
 light than pure hydrogen alone. But it does not support 
 combustion, and is speedily fatal to animal life. Mixed with 
 atmospheric air it forms a powerful explosive compound, 
 which, on the application of the flame of a candle, detonates 
 with great violence. When burnt in oxygen it is decom- 
 posed, its hydrogen combining partly with the oxygen to 
 
CARBON. 
 
 131 
 
 water, and its carbon forming with the remaining oxygen 
 carbonic acid. 
 
 We have mentioned in 82 that light carburetted hydrogen 
 is spontaneously formed in coal mines, where by its explo- 
 sions it proved frequently destructive to the workmen. This 
 is so much more the case as the miners have no warning of its 
 presence ; it being lighter than atmospheric air, and on that 
 account collects above the ground on which they work. To 
 this must be added the necessity under which miners are to 
 work by the light of lamps, in the immediate neighborhood of 
 such an explosive compound, which frequently covers whole 
 acres of surface, and extends several hundred perpendicular 
 feet in height. 
 
 Now it has been observed that a high degree of temper- 
 ature is necessary to ignite all inflammable mixtures of 
 fases ; and that metnllic wire, even when red hot, is insuf- 
 cient for this purpose ; but that the flame of a candle will set 
 fire to them ; because the heat which is given out by it, is much 
 greater than that of any red-hot rnotal. This observation, to- 
 gether with the discovery of Dr Wollaston, that explosive mix- 
 tures cease to burn in very narrow tules, led Sir Humphrey Davy 
 to suppose that if the flame of a candle or lamp were com- 
 pletely surrounded by wire-gauze, consisting of very fine 
 meshes, it would perhaps protect the gas from being ignited, 
 and yet afford, through the small apertures of the gauze, suffi- 
 cient light for the miners to work by. This idea was most 
 completely realized by the invention of his safety lamp ; which 
 is now generally used by miners, and by which thousands of 
 lives are annually protected against the consequences which 
 might attend explosions in coal mines. 
 
 Fig. C.V. 
 
 It consists of a cistern C, containing 
 all that is necessary for a common lamp, 
 and having a spout D, on its side for the 
 purpose of feeding it with oil. The 
 flame of the lamp is covered by a cylin- 
 der of wire-gauze, which is supported 
 by three brass rods, to which is fixed the 
 cover, and a ring or handle by which the 
 whole is carried. A represents a piece 
 of wire which moves up and down in a 
 tube, and by which the lamp is trimmed 
 without establishing a direct communi- 
 cation between it and the external air. 
 This lamp, upon experiment, has been 
 found to answer all the purposes for 
 which it was intended, and may be car- 
 ried with perfect safety into the most 
 
132 
 
 CARBON. 
 
 explosive mixtures of gases, even when the wire-gauze has 
 become red-hot by heat for the gas will not be ignited by it. 
 
 Query What is the reason the flame does not pass 
 through the wire-gauze of Sir Humphrey Davy's safety- 
 lamp ? Jlns. Because the meshes of which it consists act 
 as so many narrow tubes through which (according to Dr 
 Wollaston's experiments) the flame of the lamp does not pass ; 
 and the red-hot wire, of itself, is not sufficient to ignite it. 
 Ques. But what is the reason the flame does not pass through 
 the wire-gauze ? JIns. Because the flame coming in con- 
 tact with the wire, which is a good conductor, its heat becomes 
 latent or hidden (Natural Philosophy, Chap. VI), which reduces 
 its temperature below that which is necessary to ignite gas.* 
 
 That wire-gauze does completely intercept the flame of any 
 burning substance, may yet be shown by the following easy 
 
 EXPERIMENT. Provide a bottle filled with hydrogen gas ; 
 Fig. CVI. 
 
 through its neck introduce a narrow pipe, and ignite the gas 
 which will escape through the rnouth of the pipe (see experi- 
 ment, Fig. LXXXIII, page 69). If a piece of wire-gauze is 
 held over the flame, as represented in A, the flame will be flat- 
 tened down, but it will not pass through the gauze ; if on the 
 contrary the gas is ignited above the gauze, as represented in 
 Fig. B, then it will indeed burn freely ; but the flame will not 
 be communicated to the pipe. This serves to explain the op- 
 eration and usefulness of the safety-lamp. 
 
 * The learner ought to recollect that the flame of a lamp or candle 
 consists of burning gas or vapors (see Fig. LXII and LXIII, Chap. 
 I, page 53> 
 
CARBON. 133 
 
 Carburetted Hydrogen Olefiant gas. 
 
 Chemical Composition : 2 equivalents of carbon, 
 
 (each = 6) = 12 
 2 equivalents of Hydrogen (each = 1)= 2 
 
 Chemical equivalent of Carburetted Hydrogen = 14. 
 
 84. This compound is altogether a product of art. It 
 may be obtained by dry distillation of animal or vegetable 
 substances, or from a mixture of one volume of alcohol and 
 four volumes of strong sulphuric acid, gently heated in a 
 retort. The mixture will soon turn black, and emit the gas. 
 which may be collected over water as in the usual way. 
 
 Alcohol is a compound of carbon, hydrogen, and oxygen, 
 as we shall see in the 7th Chapter, when treating on vege- 
 table chemistry ; but when sulphuric acid is added, which has 
 a great affinity for water, (contained in the alcohol), it sets the 
 carbon and part of the hydrogen free, which combine with 
 each other, to olefiant gas. 
 
 85. Properties of Carburetted Hydrogen, or Oleji- 
 ant Gas. It is a perfectly colorless, elastic fluid, of a disa- 
 greeable smell, (but no taste) which is easily inflammable 
 and burns with a yellowish white flame, much brighter 
 than the common flame of a taper. When mixed with 
 oxygen and ignited, it detonates with great violence. By 
 passing it through a red-hot porcelain tube, it parts with a 
 portion of its carbon, by which means it becomes con- 
 verted into sub-carburetted hydrogen (see 82). 
 
 86. Applications of the Olefant Gas. The flame 
 of pure Carburetted hydrogen gas gives, as we have 
 said before, a most brilliant light, and is on that account 
 extensively used for illuminating shops and streets instead 
 of lamps and candles. 
 
 The brilliancy of the flames of other gases depends on the 
 quantity of olefiant gas which enters into their composition, 
 or, in general, upon the quantity of carbon which they contain ; 
 the light which they give out being always in proportion to that 
 substance. Diamond, which is pure carbon, when burnt in 
 oxygen gas or by the agency of a powerful galvanic battery, 
 throws out so vivid a light, that if the experiment be made by 
 12 
 
134 CARBON. 
 
 candle-light, the very flame of the candles will yet appear 
 casting a shadow on the wall. 
 
 Gas-light was employed for illumination, as long as a 
 century ago, by Dr Clayton ; but for its general introduc- 
 tion we are indebted to Mr Murdock who first intro- 
 duced it into England, from which it gradually spread all 
 over the continent of Europe, and is now successfully em- 
 ployed in some of the large cities of America. That used 
 in Europe for illuminating shops and streets, is generally 
 prepared from bituminous coal distilled in close vessels at 
 a red heat. Oil and resin have lately been employed with 
 the same good effect. In America olefiant gas is prepar- 
 ed principally from the distillation of whale oil. This is 
 done in large retorts, half filled with pieces of brick to 
 increase the heated surface. The oil is by this means de- 
 composed and yields a large quantity of gas, which is 
 much purer, and contains a greater proportion of carburet- 
 ted hydrogen than that which is prepared from coal. It is 
 on that account better adapted to the purposes of illumin- 
 ation than coal-gas ; but its preparation is much more ex- 
 pensive. Resin, by a peculiar treatment has been dis- 
 covered to yield the same gas at only one fourth of the 
 expense of the gas prepared from oil, and is now much 
 employed in the shops of London and Paris. The gas 
 which is thus obtained is conducted in pipes to the place 
 where it is to be burned. 
 
 The reason why carburetted hydrogen has also been called 
 olefiant gas, is because it readily combines with chlorine to a 
 yellowish liquid resembling oil. 
 
 Besides carburetted and sub-carburetted hydrogen, there 
 exist yet a number of other combinations between hydrogen 
 and carbon, the precise composition of which has not as yet 
 been ascertained. 
 
 Combination of Carbon with Nitrogen Cyanogen. 
 Chemical composition of Cyanogen. 
 
 2 equivalents of Carbon (each = 6) = 12 
 1 equivalent of nitrogen = 14 
 
 Consequently, chemical equivalent of Cyanogen = 26. 
 87. Carbon combines with nitrogen and forms with 
 
CARBON. 135 
 
 it a gas, which is called carburet of nitrogen or cyanogen 
 This gas does not occur in nature ; but may be obtained 
 by art, by boiling a substance called Prussian blue with red 
 oxide of quicksilver in a sufficient quantity of water. By 
 this means a compound is obtained, which upon cool- 
 ing shoots into crystals, and is called cyanuret of mercury. 
 This substance when dried at a temperature a little below 
 the boiling point, and afterwards in a retort exposed to a 
 gentle heat, becomes dark and liquid, and gives off a gas 
 which may be collected over quicksilver. This gas is the 
 carburet of nitrogen, or cyanogen. 
 
 88. Properties of Cyanogen. It is a colorless, in- 
 flammable gas, which has a pungent smell and affects the 
 eyes. Its most remarkable property consists in its capa- 
 city to combine with other substances in a manner similar 
 to oxygen, although it is a compound, and oxygen is an 
 element. On this account it has been called cyanogen, an 
 appellation resembling that of other elements (hydrogen, 
 oxygen, nitrogen, &,c.) from two Greek words signifying 
 ' formation of blue/ because it is a principal ingredient of 
 Prussian blue. On this account we shall make an exception 
 to the general principle laid down in the plan of this trea- 
 tise, to treat in the first three chapters only of the ele- 
 ments and their binary compounds and proceed imme- 
 diately with the 
 
 Combinations of Cyanogen with Oxygen. 
 
 89. Cyanogen combines with oxygen in three dif- 
 ferent proportions, forming with it three different com- 
 pounds, viz : Cyamms acidjfulminic acid, and cyanic acid. 
 All these substances are products of art (the latter has 
 only been discovered in 1828) and may be obtained indi- 
 rectly from the action of alcohol on some of the salts called 
 nitrates. (See Chap. IV). Their chemical composition 
 is not yet satisfactorily determined. 
 
 Combination of Cyanogen witli Hydrogen Prussic Acid. 
 
 Chemical composition : 1 equivalent of Cyanogen = 26 
 1 do. Hydrogen = I 
 
 Chemical equivalent of Prussic acid = 27 
 
136 CARBON. 
 
 90. A combination of Cyanogen with hydrogen is 
 called hydro-cyanic or Prussic acid. This acid is contain- 
 ed, and may be extracted from many vegetables, particular- 
 ly from bitter almonds, from the stones of peaches, prunes, 
 cherries, &c ; in short from all vegetable substances which 
 smell like bitter almonds. But it may also be obtained 
 from Prussian blue, by the following complicated process : 
 Mix together 4 ounces of powdered Prussian blue, 2^- 
 ounces of red oxide of mercury, and about 12 ounces of 
 water ; boil the mixture half an hour, and stir it frequently 
 during that time. When the blue color of the mixture has 
 disappeared and changed into a yellowish green, filter the 
 solution, and add to the residue a sufficient quantity of boil- 
 ing water to make up for the loss by the first boiling. When 
 this solution is again filtered, put it into a tubulated retort r, 
 
 Fig. CVII. ( see tlie fig ure ) containing 
 
 2 ounces of iron filings, and 
 pour upon it, through the 
 opening b, 3 or 4 ounces of 
 dilute sulphuric acid. Con- 
 nect the retort now with a 
 receiver a, and apply to it 
 the flame of a lamp. Va- 
 pors of Prussic acid will 
 be formed in the retort r, 
 which may be condensed in 
 the receiver a, by covering 
 it with a wet cloth, for the 
 purpose of keeping it cool 
 and secluding it from the 
 light. The distillation may 
 be continued until about 
 three ounces of Prussic acid 
 are obtained. 
 
 The generation of Prussic acid by the process we have 
 just described is accounted for in the following manner. 
 Prussian blue is a combination of Prussic acid with iron ; 
 but when the red oxide of mercury is added, for which 
 the Prussic acid has a stronger affinity than for iron, it 
 quits its combination with this substance and unites with 
 
CARBON. 137 
 
 the oxide of mercury to a salt called Prussiate of Mercu- 
 ry, which is immediately dissolved by the boiling water. 
 When the iron-filings and the sulphuric acid are added to 
 this solution, the iron combines with the oxygen of the 
 oxide of mercury, setting the mercury free, which is pre- 
 cipitated to the bottom, while the oxide of iron which is 
 thus formed, combines with the sulphuric acid to another 
 salt, which is called Sulphate of Iron. The Prussic acid, 
 which by this means becomes completely disengaged from 
 its new combination with mercury, is by the heat of the 
 lamp volatilized, and passes in form of vapors into the re- 
 ceiver, where, in contact with the cold glass, it is again 
 condensed into the liquid form. 
 
 91. Properties of Prussic, or hydro-cyanic acid. It is 
 a clear, colorless liquid ; has a strong (somewhat penetra- 
 ting) smell, resembling that of peach blossoms, and when 
 strongly diluted with water, has a cooling, pungent taste, 
 like bitter almonds. In its pure state it is the most pow- 
 erful poison in nature. A few drops placed on the tongue 
 of a small animal causes its death in a very few seconds. 
 An elephant was killed by a hundred drops of it, and Prof. 
 Wahring, of Vienna, died by diffusing a small quantity of 
 it on his naked arm. The vapors of this gas are inflam- 
 mable, and when mixed with oxygen, detonate on the ap- 
 plication of an electric spark. It boils at a temperature 
 of about 80 degrees Fahrenheit, and congeals a little be- 
 low zero. Diluted with water it is employed in medicine ; 
 and it is also used in the dyeing of broadcloths. 
 
 It is liable to spontaneous decomposition into its ele- 
 ments, which seem to have but a feeble affinity for each 
 other, and is on this account, difficult to preserve, even in 
 close vessels arid secluded from the light of day. 
 
 The first stage of its decomposition is marked by the 
 liquid assuming a brown color, which soon turns into 
 black and deposites a dark sediment. When arrived at 
 this stage it loses its peculiar smell and emits that of am- 
 monia (see 62, page 102). It is then no longer a poison 
 and has lost all its characterising properties 
 
 92. Prussic acid differs from the acids we have thus 
 far become acquainted with, in the following properties : 
 12* 
 
138 CARBON. 
 
 1st. In its chemical composition ; it being a combina- 
 tion of three elements, (nitrogen, carbon, and hydrogen) 
 without oxygen, and 
 
 2d. By its possessing the acid qualities in a very feeble 
 degree ; for it has neither a sour taste, nor does it redden 
 litmus paper ; 
 
 But in combination with those substances called bases 
 it forms, as we shall see, salts like the rest of the acids 
 (see Introduction, page 38) ; and when separated from 
 these again by the agency of galvanic electricity, it ad- 
 heres to the positive pole showing thereby that it is a 
 negative electric. (Compare what we have said in the 
 Introduction, page 38, with regard to the nature of acids). 
 
 When a quantity of potassium sufficient to absorb 50 
 measures of cyanogen is heated with 100 measures of vapors 
 of Prussic acid, the 50 measures of cyanogen are wholly ab- 
 sorbed, and nothing but 50 measures of pure hydrogen remain ; 
 which proves that Prussic acid is composed of equal volumes of 
 cyanogen and hydrogen. But as the cyanogen is about 26 
 times heavier than hydrogen (its specific gravity being nearly 
 26 times that of hydrogen), it follows that its composition, by 
 weight is 1 equivalent of hydrogen to 26 of cyanogen, as sta- 
 ed at the head of the 87th section. 
 
 Other Combinations of Cyanogen. 
 
 93. Cyanogen combines yet with Chlorine in two 
 proportions, forming with it Proto-chloride and per-chlo- 
 ride of Cyanogen. In a similar manner does it combine 
 with the two elements Iodine and Bromine.. All these 
 substances have similar properties ; they are possessed of 
 a peculiar, irritating odor, and are active poisons. 
 
 A compound of cyanogen and sulphur is called sulphu- 
 retted cyanogen. It is colorless, has a pungent smell, and 
 reddens litmus paper. 
 
 Combinations of Carbon with Chlorine. 
 
 94. Carbon and chlorine combine with each other 
 in three different proportions, forming sub-chloride, chlo- 
 ridej and per-chloridc of carbon. All these combinations 
 are mere products of art, and are as yet little employed in 
 the arts. 
 
CARBON. 139 
 
 Combination of Carbon with Sulphur Sulphuret of 
 Carbon. 
 
 Chemical composition : 1 equivalent of Carbon = 6 
 2 equivalents of sulphur (each being 16) = 32 
 
 Consequently, chem. equiv. of Sulphuret of Carbon = 38. 
 
 95. Carbon and sulphur may be made to combine 
 by the following process, described in the Library of Use- 
 ful Knowledge. Place an earthen tube of about an inch 
 
 Fig. CVJII. 
 
 and a half in diameter, a little inclined across a charing 
 dish, and fill it nearly with small pieces of charcoal, well 
 burnt and quite free from moisture. To the higher end of 
 this tube adapt a glass tube filled with small pieces of sul- 
 phur, which may be pushed forward by means of a wire 
 passing air-tight through a cork. To the other end of the 
 earthen tube, a bent glass tube must be adjusted, which 
 must pass below the surface of some water contained in a 
 bottle. When the fire in the chafing dish has been light- 
 ed, and the centre of the tube become red-hot, the sul- 
 phur in th'e glass tube must be pushed forward to come 
 in contact with the ignited charcoal, and immediately bub- 
 bles of gas will escape from under the water into the bottle, 
 and a vapor will appear, which will condense under the 
 water into a liquid. This is sulphuret of carbon mixed 
 however with a portion of water, from which, and other 
 impurities, it may be freed by distilling it over at a gentle 
 heat (not exceeding 110 degrees Fahrenheit), in a retort 
 containing a little^ chloride of calcium, a substance which 
 absorbs water very rapidly. 
 
 96. Properties of Sulphuret of Carbon. It is a 
 colorless, transparent liquid, has a strong acid (not acrid) 
 
140 
 
 CARBON. 
 
 taste, a nauseous, fetid smell, and is so exceedingly volatile 
 as to boil already at a temperature of 1 10 degrees Fahren- 
 heit. Its boiling point, therefore, is 102 degrees below that 
 of water. This is the reason why in distilling it over, the 
 heat applied to it must not exceed 1 10 degrees Fahrenheit. 
 No degree of artificial cold has ever made it congeal ; but 
 it is highly inflammable, and emits during its combustion 
 copious fumes of sulphuric acid (owing to its decomposition, 
 in consequence of which the sulphur combines with the 
 oxygen of the atmosphere to sulphuric acid). It is 
 heavier than water, its specific gravity being 1 .27, that of 
 water being 1 ; which is the reason why it falls to the bot- 
 tom when poured into water. Owing to its great volatility 
 it is a highly refrigerating substance. A thermometer 
 whose bulb is covered with lint that has been moistened 
 with sulphuret of carbon, will rapidly fall to zero. Under 
 the receiver of an air-pump (when the pressure of atmos- 
 pheric air is removed) it is capable of causing even quick- 
 silver to freeze. 
 
 Recapitulation of tlw, principal binary and ternary Com- 
 binations of Carbon. 
 
 Carbon 
 combines 
 with 
 
 Nitrogen to 
 
 Cyanogen, 
 
 which com- 
 
 bines again 
 with 
 
 C cyanous } 
 oxygen tolfulminic >acid. 
 
 ( cyanic ^ 
 hydrogen to Prussic acid. 
 
 . protochlo- . 
 chlorine to { ride ^ot Cyan- 
 
 (per-chlorideY gen- 
 sulphur to sulphuretted cyanogen. 
 C sub-chloride ^ 
 Chlorine to < chloride > of Carbon. 
 
 ( per-chloride ) 
 Sulphur to sulphuret of carbon. 
 
SULPHUR. 
 
 141 
 
 B. Sulphur. 
 
 Chemical Equivalent = 16. 
 
 97. Sulphur is one of the few elements which occur 
 in their simple form, and abound in all the three kingdoms 
 of nature, but it is particularly found in the vicinity of vol- 
 canos, and in mountains of quartz and gypsum. 
 
 It has been discovered in the sulphur mountains of Ticsan 
 near Quito ; in the valley of Noto and Mazzara ; on the banks 
 of the Salso in Sicily ; in Spain ; in Poland (near Krakau) ; in 
 Auvergne, near Mount Vesuvius, and in a crystallized state 
 (sofatora) near Puzuoli in the kingdom of Naples and in the 
 neighborhood of Mount JEtna, in Iceland, in Teneriffe, Guada- 
 loupe, Java, and the Island of Bourbon. The volcano Purace, 
 in South America, covers its immediate vicinity with crusts 
 of sulphur. 
 
 Sulphur is also contained in many plants, especially in 
 mustard, onions, and garlic, and in many animal sub- 
 stances, especially in the eggs of fowls. 
 Fig. CIX. 
 
 To purify it from stones and oth- 
 er earthy substances, it is melted 
 and distilled (sublimed). For this 
 purpose a heat of about 500 de- 
 grees Fahrenheit may be applied 
 to some sulphur in a retort. It 
 will first melt and then be changed 
 into vapors, which when coming 
 in contact with the colder receiver 
 are condensed again and adhere to 
 the sides of the glass in form of a 
 fine powder called jlour of sulphur. 
 The properties of this powder are 
 yet the same as that of sulphur. 
 
1 42 SULPHUR. 
 
 98. Propertiesof Sulphur. Sulphur is a greenish-yel- 
 low, tasteless mineral ; which is highly inflammable, burns 
 with a faint blue light, and emits when rubbed, or during 
 combustion, a peculiar suffocating odor. The heat which 
 it throws out is so small that it may be burnt out of gun- 
 powder, of which it is a principal ingredient, without ignit- 
 ing it. Its specific gravity is 1.92 (water being 1), and it 
 is therefore nearly twice as heavy as water. At the tem- 
 perature a little above the boiling point of water it be- 
 comes liquid, and is then cast into moulds and sold in 
 commerce under the name of roll-brimstone. When in a 
 state of fusion it is poured into water it becomes of a 
 consistency like wax, and is then used for taking impres- 
 sions of coins, medals, cameos, &c, for which purpose it 
 is particularly adapted ; because its color, when fused, 
 changes into brown, and resembles that of bronze. The 
 applications of sulphur are numerous. It is used for 
 matches ; in the manufactory of gun-powder (of which ii, 
 forms a principal ingredient), in the preparation of sul- 
 phuric acid, of cinnabar, of blue vitriol, &,c. and it is also 
 extensively employed in medicine. 
 
 Combination of Sulphur with Oxygen. 
 
 99. Sulphur combines with oxygen in four differ- 
 ent proportions ; in the proportion of 1 to 1 , 1 to 2, 2 to 
 5, and 1 to 3 equivalents, forming with it hypo-sulphurous 
 acid, sulphurous add, hypo-sulphuric acid, and sulphuric 
 acid. The first and third of these combinations are pro- 
 ducts of art, and of little use in common life ; but the 
 second and fourth are highly important to the manufac- 
 turer and the physician. We shall therefore treat only 
 of sulphurous and sulphuric acid. 
 
 Sulphurous Acid 
 
 is composed of 1 equivalent of sulphur = 16 
 and 2 equivalents of oxygen (each 8) = 16 
 
 Consequently, chem. equiv. of sulphurous acid = 32. 
 
 100. This compound is, in]a gaseous form, contained 
 in the atmosphere in the vicinity of volcanos. It is also 
 
SULPHUR. 143 
 
 found (absorbed) in water : but may be obtained also by 
 burning sulphur in atmospheric air. It may also be pro- 
 duced in a state of great purity by the action of sulphuric 
 acid (for the preparation of which see the following sec- 
 tion) on mercury. A mixture of these two substances 
 may be gently heated in a retort, and the gas which will 
 be given off collected over mercury water having too 
 great an affinity for it. 
 
 This process is easily explained in the following manner : 
 sulphuric acid is a compound of 1 equivalent of sulphur with 
 three of oxygen. When this is heated with mercury for which 
 its oxygen has a great affinity, one equivalent of oxygen com- 
 bines with the metal, and the two equivalents of oxygen which 
 remain united with the sulphur, form sulphurous acid gas. 
 
 101. Properties of Sulphurous Add. It is a col- 
 orless, transparent gas, which possesses a peculiar smell 
 and extinguishes all burning bodies. It is itself incom- 
 bustible, and when taken into the lungs causes coughing 
 and suffocation. By a pressure of 30 pounds to the square 
 inch, it becomes liquefied. It is speedily absorbed by water, 
 which is capable of absorbing more than 33 times its own 
 bulk of it, and forms with it what is properly called liquid 
 sulphurous acid; but it cannot in this state be preserved 
 for any length of time. 
 
 All vegetable colors, with the exception of cochineal, 
 are destroyed by it. (Blue vegetable colors are first turn- 
 ed into red and then wholly discharged ; cochineal is 
 only turned lighter, and changes into a yellowish red.) It 
 is extensively used in bleaching, especially for silk and 
 straw ware. 
 
 Sulphuric Acid (Oil of Vitriol). 
 
 Chemical composition : 1 equivalent of Sulphur = 16 
 3 equivalents of Oxygen (each = 8) = 24 
 
 Chemical equivalent of sulphuric acid = 40. 
 
 102. Sulphuric acid is the highest degree of oxy- 
 genation of which sulphur is capable. It occurs in nature 
 diluted with water in the Rio Vinagre, in South America; 
 in the Indian Lake at Java, and in Italy, and is of all the 
 
144 SULPHUR. 
 
 acids the most important to the arts. It is therefore man- 
 ufactured in great quantities, and forms an important arti- 
 cle of commerce. 
 
 In commerce there are two sorts of sulphuric acid, 
 Hydro-sulphuric acid, or oil of vitriol, and sulphuric acid 
 properly speaking. The first is obtained from a substance 
 called green vitriol of iron, and the second from burning 
 saltpetre with sulphur. 
 
 The process by which the oil of vitriol is procured is the 
 following : Green vitriol, copperas, or as it is properly called, 
 sulphate of iron (because it is composed of sulphuric acid and 
 protoxide of iron) is distilled at a high heat, by which means it 
 becomes decomposed, and a dense, oily, colorless liquid is ob- 
 tained, which in contact with the atmosphere emits copious 
 white vapors. This liquid is afterwards again distilled at a 
 lower temperature, and made to pass into a receiver surrounded 
 with ice, where it forms transparent, colorless vapors, which 
 condense into a white, crystalline solid. This is supposed to 
 be the sulphuric acid in an an-hydrous state (without water), 
 and the residue in the retort, which is now no longer fuming, 
 is the common oil of vitriol as it occurs in commerce. The 
 solid substance liquefies again at a temperature a little above 
 60 degrees Fahrenheit, and has so strong an affinity for water, 
 that it absorbs it from the atmosphere as soon as it is brought 
 in contact with it. 
 
 Hydro-sulphuric acid (sulphuric acid dissolved in water) 
 which is the sulphuric acid of commerce, is manufactured in 
 large quantities by burning a mixture of 8 parts of sulphur 
 and 1 of nitre in close leaden chambers, containing at the bot- 
 tom a small sheet of water. During combustion fumes of 
 sulphuric acid rise and are absorbed by the water ; from which 
 the acid is afterwards obtained in a concentrated state by 
 evaporating the solution. The theory of this process is some- 
 what complicated, and will be best understood from the fol 
 lowing table. 
 
SULPHUR. 
 
 145 
 
 Liquid 
 sulphuric acid. 
 
146 SULPHUR. 
 
 Nitre is a compound of oxide of potassium with nitric acid, 
 which, as we know, is composed of nitrogen and oxygen ( 56, 
 page 99). Now when sulphur is burnt with nitre in chambers 
 containing atmospheric air, the product of the combustion are 
 sulphurous acid (a combination of sulphur with the oxygen of 
 the atmosphere) and sulphuric acid, (a combination of the oxy- 
 gen of the nitre, with the sulphur). The sulphuric acid thus 
 generated, combines with the oxide of potassium to sulphate 
 of potash, setting nitrous oxide, or deutoxide of nitrogen free. 
 But the heat given out during the process of combustion ex- 
 pands this gas and makes it rise to the top of the chambers, 
 where, by an aperture, it is made to communicate with the 
 atmosphere, from which it absorbs another portion of oxygen, 
 and is thereby converted into nitrous acid vapor. These va- 
 pors being specifically heavier than air, sink down upon the 
 sulphurous acid, and yield to it another equivalent of oxygen, 
 converting it thereby into sulphuric acid ; which being rapidly 
 absorbed by the water, is immediately obtained in the liquid 
 (hydrous) state. The nitrous acid vapors which have now 
 lost a portion of their oxygen, are again transformed into 
 nitrous gas, which does then reascend to the roof of the 
 chamber, where by the aperture it is as before brought in 
 contact with atmospheric air, from which it absorbs a fresh 
 portion of oxygen and is converted into nitrous acid vapor. 
 These sink again upon the sulphurous acid, and convert 
 another portion into sulphuric acid ; and so is this process 
 continued until all the sulphurous acid formed, is converted 
 into liquid sulphuric acid. Eight parts of sulphur and one 
 part of nitre will in this manner produce 20 parts of sulphuric 
 acid. 
 
 103. Properties of the Oil of Vitriol, and of Liquid 
 
 Sulphuric Jldd. The oil of vitriol, in its pure state, is a 
 colorless, oily liquid, which destroys rapidly all animal and 
 vegetable substances, but may be mixed with water in any 
 proportion. (The yellowish brown tinge which the oil of 
 vitriol of commerce generally has, is derived from organic 
 substances, such as cork, wood, straw, &c, accidentally 
 dropped into it). The Hydro-sulphuric Acid, when 
 pure, is a colorless, oily liquid. It is inodorous, and dilute 
 with water (without water it is an active poison) has a strong 
 acid taste. It may be mixed with water in any propor- 
 tion, and reddens litmus paper even when largely diluted 
 with it. Its specific gravity when most concentrated, is 
 
SULPHUR. 147 
 
 1.85, that of water being 1. If it is much heavier, it is 
 a sign that it contains some foreign heavy substances 
 (commonly sulphate of soda or lead, from the manner in 
 which it is manufactured in leaden chambers), and if it is 
 much lighter it shows that it has been diluted with water. 
 Owing to its great affinity for water, it rapidly destroys all 
 organic substances of whose composition water forms a 
 large ingredient, and converts theni (by absorption) into 
 charcoal. Its boiling point is about 620 degrees Fahren- 
 heit, and it crystallizes at about 15 below zero. 
 
 104. Of the numerous applications of sulphuric acid 
 to the arts we will only mention a few highly important 
 ones. To those belong the use which is made of it in the 
 manufacture of Glauber's salts, so extensively used in med- 
 icine (see Chap. IV Sulphate of Soda) ; in the bleach- 
 ing of linen and cotton, in the cleansing of rags for the 
 manufactory of paper ; in the dyeing and printing of cali- 
 cos, &-c. The annual consumption of sulphuric acid, in 
 England alone, amounts to 3000 tons ! ! 
 
 Combination of Sulphur with Hydrogen. 
 
 105. Sulphur combines in two different proportions 
 with hydrogen, viz : In the proportion of I equivalent of 
 sulphur with I equivalent of hydrogen, and in the pro- 
 portion of '2 equivalents of sulphur with 1 equivalent of 
 hydrogen, the products being sulphuretted hydrogen, and 
 bi-sulphuretted hydrogen. (The syllable c 6t' signifying 
 double ; because sulphur is combined with a double pro- 
 portion of hydrogen). 
 
 Sulphuretted Hydrogen 
 
 is composed of 1 equivalent of sulphur = 16 
 1 do. of hydrogen = 1 
 
 Chemical eqvivalent of Sulphuretted hydrogen = 17. 
 
 106. Sulphuretted hydrogen occurs in nature, combin- 
 ed with water or alkalies. It is also given off during the 
 putrefaction of a variety of animal substances ; and may 
 be easily obtained for the sake of experiment, by subliming 
 
148 SULPHUR. 
 
 sulphur in hydrogen gas (see the experiment represented 
 in Fig. CIX, page 141). The two elements, hydrogen 
 and sulphur, combine during this process without a 
 change of volume. It may also be produced in abundance 
 by the action of sulphuric acid on sulphurct of iron, a 
 substance obtained by melting together sulphur and iron 
 filings. Sulphuretted hydrogen is by this means ob- 
 tained by elective affinity ; the oxygen contained in the 
 water of the hydro-sulphuric acid unites with the metal 
 which remains dissolved in the acid, setting hydrogen and 
 sulphur free, which unite with each other to sulphuretted 
 hydrogen. 
 
 107. Properties of Sulphuretted Hydrogen. Sul- 
 phuretted hydrogen is a colorless, inflammable gas, which 
 smells and tastes after foul eggs, and burns with a light 
 blue flame. It is incapable of supporting combustion and 
 totally irrespirable ; when taken into the lungs it causes 
 cramp and suffocation. It is so exceedingly fatal to an- 
 imal life that a dog dies in an atmosphere containing only 
 ^thy ; and a horse in one, which contains only ^^ part of 
 this gas. When dissolved in water, it acts like an acid, 
 and reddens litmus paper (see Introduction, page 3S). By 
 cold and pressure it may be reduced to the liquid state ; 
 but it is immediately transformed again into gas, when 
 brought in contact with the atmosphere. 
 
 It is also remarkable for its action upon almost all me- 
 tallic oxides; when gently heated, and brought in contact 
 with sulphuretted hydrogen, they form sulphurous metals 
 and water (the hydrogen combining with the oxygen of 
 the oxide, and the sulphur with the metal). It is easily 
 decomposed by sulphuric acid ; but more especially by 
 chlorine. Hence the use of chloride of lime in purifying 
 the air from the exhalations of putrefying organic matter. 
 
 108. Sulphur combines also with chlorine (wherefore 
 sulphuretted hydrogen is decomposed by chlorine), Bro- 
 mine, and Iodine. Neither of these combinations is of 
 much use in the arts. But sulphur is not known to com- 
 bine with nitrogen. 
 
SELENIUM. PHOSPHORUS. 149 
 
 Recapitulation of the principal Binary Combinations of 
 Sulphur. 
 
 C hypo-sulphurous } 
 oxygen to < sulphurous > acid. 
 
 Sulphur } (. hypo-sulphuric 
 
 combines with 
 
 C. Selenium. 
 
 Chemical Equivalent = 40. 
 
 109. This substance has but lately (in 1817) been 
 discovered by Berzelius, a celebrated Swedish chemist. 
 It occurs in very minute quantities, combined with some of 
 the metals, such as lead, copper, cobalt, quicksilver, silver, 
 gold, &c, and is only separated from them by an extremely 
 tedious process. After fusion it has a greyish color, and a 
 metallic lustre. When rapidly cooling its color is reddish 
 brown as a powder it has a deep red color. It is brittle, 
 boils at about 12 degrees above the boiling point of water, 
 and when warm is very ductile. 
 
 Selenium combines in three different proportions with oxy- 
 gen. The compounds are oxide of 'selenium, selenious acid, and 
 silenic acid. With hydrogen it is only known to combine in 
 one ratio, forming with it selenielted hydrogen. With sulphur 
 it unites in all proportions, the various products being known 
 by the name' of sulphuretted selenium. 
 
 D. Phosphorus. 
 
 Chemical Equivalent = 1 2, (doubtful). 
 
 110. Phosphorus is a light yellow, soft solid, which 
 at the mean temperature of the atmosphere is of the con- 
 sistency of wax, and exposed to the atmosphere emits 
 white luminous vapors. It is chiefly contained in the 
 bones of animals, and has not as yet been found in its 
 
 13* 
 
150 PHOSPHORUS. 
 
 simple form. It may, however, be easily procured by the 
 following process. 
 
 Reduce a quantity of bones, which have been burnt in an 
 open fire to a fine powder ; and digest them for several days 
 with half their weight of concentrated sulphuric acid, adding 
 enough water to give the mixture the consistency of a thin 
 paste. The solution is then mixed with twice its bulk of hot 
 water, and after being well stirred, filtered through a straining 
 cloth. (See Fig. IX, page 18). 
 
 This solution is again evaporated to the consistency of syrup ; 
 then mixed with one fourth its weight of powdered charcoal, 
 and strongly heated in an earthen retort. A large quantity 
 of gas will be formed during this process, which, when the 
 mouth of the retort is conducted into a receiver filled with 
 water, will distil over in drops, which will congeal in contact 
 with the water. The solid thus obtained is pure phosphorus. 
 
 To understand this process it is necessary to state that all 
 bones are composed of a particular salt called phosphate of 
 lime, mixed, however, with a variety of animal substances. 
 By burning bones in an open fire (which process is also called 
 calcination) the phosphate of lime is separated from these sub- 
 stances, and when subsequently digested with concentrated 
 sulphuric acid, decomposed into its constituent principles, 
 phosphoric acid and lime. The lime unites by elective affini- 
 ty with the sulphuric acid to an insoluble compound (sulphate 
 of lime) and the phosphoric acid remains dissolved in the solu- 
 tion ; consequently, when the solution is filtered, nothing but 
 pure sulphuric acid will pass through the straining cloth. 
 When the solution is afterwards evaporated and distilled with 
 charcoal at a strong heat, the charcoal unites with the oxygen of 
 the acid and sets the phosphorus free. This passes in form of 
 gas from the retort into the receiver, and congeals in contact 
 with the water. 
 
 111. Properties of Phosphorus. Pure phosphorus, 
 obtained in the manner we have just described, is a soft, 
 yelolw solid, which by exposition to solar light, espe- 
 cially to the violet rays of the spectrum, changes into 
 red, but rnay be rendered perfectly colorless by a second 
 distillation. It is so exceedingly inflammable that it may 
 be ignited by mere friction, or by the natural heat of the 
 palm of the hand. Owing to its great affinity for oxygen 
 it combines with it at the common temperature of the at- 
 
PHOSPHORUS. 151 
 
 mosphere, so that in order to preserve it, it is necessary to 
 keep it under water. In contact with air it emits a light 
 smoke (owing to its slow combustion with oxygen) and 
 a smell somewhat like garlic; but in the dark it throws 
 out a beautiful greenish light. Its specific gravity is 1.7, 
 that of water being 1. It is perfectly tasteless, but when 
 taken into the stomach proves a very active poison. 
 
 It is insoluble in water, but readily combines with oil 
 or ether, to which substances it communicates the proper- 
 ty of throwing out light in the dark. 
 
 Its affinity for oxygen is so great that it will take up of 
 this gas more than 1J times its own weight, and so easily 
 does it ignite by friction that it is used in the construction 
 of phosphoric match boxes. 
 
 Combinations of Phosphorus with Oxygen. 
 
 112. Phosphorus combines with oxygen in five dif- 
 ferent proportions, forming with it two oxides and three 
 acids, viz : White oxide of Phosphorus, Red oxide 
 of Phosphorus, hypo-phosphorus acid, Phosphorous aczW, 
 and Phosphoric acid. The exact proportions in which 
 phosphorus combines with oxygen being not known, and 
 these compounds being of little application to the arts, we 
 will only describe the most remarkable of them, 
 
 Phosphoric Acid, 
 
 which is composed of 1 equivalent of Phosphorus = 12 
 and 2 equivalents of Oxygen (each = 8) = 16 
 
 Consequently, chemical equiv. of Phosphoric acid = 28. 
 
 113. This compound of phosphorus occurs in na- 
 ture, combined with lime, clay, oxide of iron, lead, cop- 
 per and manganese, &,c ; but it may be obtained by art, by 
 
152 
 
 PHOSPHORUS. 
 
 Fig. CX. 
 
 burning phosphorus in atmospher- 
 ic air, or better in pure oxygen 
 gas, (see the adjoining figure). 
 (The phosphorus may be ignited 
 by a red-hot wire, and must be in- 
 troduced into the jar from under 
 the water, to prevent spontaneous 
 combustion by friction or the heat 
 of the hand). During combustion 
 dense white vapors will be form- 
 ed, which, like snow, fall to the 
 bottom of the jar, and consti- 
 tute what is called the pure, an- 
 hydrous, phosphoric acid. This 
 unites afterwards with the water to hydro-phosphoric acid, 
 and may be evaporated to dryness. It may also be obtain- 
 ed from the action of phosphorus or nitric acid, or by di- 
 gesting calcined bones with sulphuric acid, as we have 
 seen in the process of procuring phosphorus. (107.) 
 
 114. Properties. Phosphoric acid is a colorless, 
 inodorous, transparent liquid, which easily absorbs water 
 from the atmosphere, and has all the essential qualities of 
 a powerful acid (Introduction, page 38). It has, however, 
 thus far, no technical application. 
 
 Combinations of Phosphorus with Hydrogen. 
 
 115. Phosphorus combines with hydrogen in two 
 different proportions ; the products are Proto-phosphuret- 
 ted hydrogen, and Per-phosphuretted hydrogen. 
 
 Proto-phosphur cited Hydrogen 
 
 is composed of 1 equivalent of Phosphorus = 12 
 and 2 equivalents of Hydrogen (each 1) = 2 
 
 Consequently, chemical equiv. of Proto-phosphu- 
 
 retted hydrogen = 14. 
 
PHOSPHORUS. 
 
 153 
 
 Per-phosphuretted Hydrogen, 
 
 on the contrary, is composed of 1 equivalent of 
 
 phosphorus = 12 
 
 1 equivalent of Hydrogen = 1 
 
 Chemical equiv. of per-phosphuretted hydrogen = 13. 
 
 Both compounds consist of phosphorus dissolved in hy- 
 drogen. 
 
 116. Per-phosphuretted hydrogen is obtained, by 
 boiling Phosphorus in a small retort with a hot solution of 
 potash, which must entirely fill the vessel. The gas thus 
 Fig. CXI. 
 
 generated must be collected by the pneumatic tub, employ- 
 ing a hot solution of potash instead of water. During the 
 boiling of the liquid, the oxygen of the water unites with 
 part of the phosphorus to phosphorus acid, which combin- 
 ing with the potash, sets the hydrogen of the water free. 
 This, under the influence of heat, combines with the re- 
 maining portion of phosphorus to phosphuretted hydrogen. 
 When the gas, as it is extricated, is allowed to escape 
 from under the surface of the alkaline solution into the air, 
 each bubble as it rises will spontaneously take fire and ex- 
 plode, leaving after the explosion an horizontal ring (see the 
 figure) of white smoke, which preserves its form for a consid- 
 erable time, and becomes larger as it ascends. 
 
 117. Properties of per-phosphuretted hydrogen. 
 Per-phosphuretted hydrogen is a colorless gas of a highly 
 
154 PHOSPHORUS. 
 
 offensive smell (resembling garlic, or foul fish), which in 
 contact with atmospheric air, or pure oxygen, becomes 
 spontaneously inflamed, and explodes, as we have seen 
 from the last experiment (Fig. CXI). It is more than 13 
 times heavier than hydrogen gas, and but slightly soluble 
 in water. When suffered to stand for some time in a 
 glass receiver, it becomes spontaneously decomposed, and 
 deposits phosphorus. A series of electric sparks pass 
 through it, produces a similar effect, and precipitates phos- 
 phorus. 
 
 Proto-phosphuretted hydrogen is produced by heating phos- 
 
 fhorus acid in close vessels, secluded from contact with air. 
 t is a colorless gas, resembling per-sulphuretted hydrogen 
 in nearly all essential properties. It does not, however, in- 
 flame spontaneously when brought in contact with atmospheric 
 air ; but when mixed with it, or pure oxygen, it detonates vio- 
 lently on the application of an electric spark. 
 
 Jl beautiful Experiment may be made by mixing 10 parts 
 of water with 1 part of phosphorus, 2 parts of granulated 
 zinc, and 6 parts of concentrated sulphuric acid. Owing to 
 the decomposition of the water, and a subsequent combination 
 of its hydrogen with the phosphorus, per-phosphuretted hydro- 
 gen, will be generated and rise in little bubbles. These, in 
 contact with atmospheric air, become spontaneously inflamed, 
 and burn with a bright flame like phosphorus. 
 
 Other Combinations of Phosphorus. 
 
 118. Phosphorus combines also with carbon, sul- 
 phur, selenium, chlorine, iodine, boron, and the metals. 
 These combinations have thus far been little examined, 
 and are of little or no application in the arts. 
 
 Recapitulation of the most important Binary Combinations 
 of Phosphorus. 
 
 ( white oxide \ c r 7 
 (red oxide \tp>>P>>""- 
 Wto hypo-phosphorous 
 
 
 **. to ***** 
 
BORON. 155 
 
 E. Boron. 
 
 Chemical Equivalent = 6, (doubtful). 
 
 119. This element is not found in its simple state ; 
 but is extracted from boracic acid, a substance we are 
 about to describe in the next section. 
 
 For this purpose potassium (a metal) may be heated with 
 boracic acid, in a copper tube to about 302 Fahrenheit. 
 When hey become red-hot, the oxygen of the acid combines 
 with the metal, and sets the boron, which is the basis of boracic 
 acid, free. 
 
 Properties. It appears as a dark green powder, which 
 is inodorous, tasteless, and but sparingly soluble in water. 
 Heated in close vessels it undergoes no change, but when 
 heated in the open air to about 600 Fahrenheit, it burns 
 with a pale green flame, the product being boracic acid. 
 
 Boracic Acid 
 
 is probably composed of 1 equivalent of boron = 6 
 and 2 equivalents of oxygen (each = 8) = 16 
 
 Whence, chemical equivalent of boracic acid = 22. 
 
 ^ 120. This is the only combination of boron with 
 oxygen. It is a substance which is generally obtained in 
 form of crystals, and is found mixed with a little sulphur 
 on the walls of cellars and caves, and at the craters of vol- 
 canos. It is also contained in some of the springs. It 
 may be obtained by art, by dissolving borax (a substance 
 resembling alum, and which is imported from India under 
 the name of Tincal), in boiling water, adding to it half its 
 weight of dilute sulphuric acid. When the solution is 
 evaporated and cooled, boracic acid is precipitated in form 
 of scaly, shining crystals. 
 
 Borax is a combination of boracic acid with soda. When it 
 is dissolved in hot water, and sulphuric acid is added, the soda 
 combines by elective affinity with the sulphuric acid, and the 
 boracic acid sinks to the bottom. 
 
 121. Properties. It is inodorous, possesses but very 
 
156 IODINE. 
 
 little taste, and is sparingly soluble in water, with which it 
 forms a solution which reddens litmus paper. It is also 
 dissolved by alcohol, to whose flame it gives a beautiful 
 green color. Boracic acid is used in the manufac- 
 tory of artificial borax, which is much employed in medi- 
 cine. It is also used in calico printing, especially in 
 France, and in coloring gold. 
 
 Boron combines yet with sulphur, chlorine, fluorine, 
 and the Metals. 
 
 F. Iodine* 
 
 Chemical Equivalent = 124. 
 
 122. This element does not occur in its simple form 
 in nature ; but is often found combined with some of the 
 metals, particularly with sodium, a substance of which 
 we shall speak in the next chapter. It has lately been dis- 
 covered also in the Mexican silver mines, and in many of 
 the lead ores of South America. It is commonly extract- 
 ed from the ashes of sea-weeds, or from a substance call- 
 ed kelp, generated during the manufacture of soda. 
 
 The process is simply this : The ashes of sea-weeds, or 
 kelp, are dissolved in water, which upon evaporation, leaves a 
 salt called carbonate of soda, in form of crystals. These be- 
 ing removed, the remaining liquid is put into a tubulated retort, 
 (see Fig. CVII, page 136), and sulphuric acid is poured upon 
 it. As soon as this is done beautiful violet vapors appear, 
 which become condensed in the receiver in crystalline plates, 
 resembling plumbago (see page 123), and may afterwards be 
 dried between folds of blotting paper. A small quantity of 
 oxide of manganese, added to the liquid in the retort, facili- 
 tates the process. 
 
 123. Properties of Iodine. Iodine is a substance 
 which at the common temperature of the atmosphere is 
 of a greyish-black color, and possesses a metallic lustre. 
 Its other .properties resemble chlorine (see 65, page 
 103), and it is a strong poison when used in large quan- 
 
 * From a Greek word signifying violet colored, because its vapors 
 have a beautiful violet color. 
 
IODINE. 157 
 
 titles. In small quantities it is used for medicinal purposes. 
 Its taste is sharp and acrid, and continues for a long time 
 upon the tongue. It destroys vegetable colors and gives 
 the skin a yellow stain, which however, soon disappears. 
 It fuses at about 225 degrees, and becomes converted into 
 beautiful purple vapors when heated to 350 degrees Fah- 
 renheit. It is (like chlorine) a non-conductor of electri- 
 city, and but sparingly soluble in water ; but is easily dis- 
 solved by ether, alcohol, or oil of turpentine. With 
 starch it forms a compound of a beautiful indigo color, 
 which affords a means of detecting its presence even in 
 very minute quantities. 
 
 It is principally used in medicine, and in the manufac- 
 tory of Iodide of quicksilver, which is a red pigment, em- 
 ployed in cotton-printing and painting. 
 
 Combination of Iodine with Oxygen lodic Acid. 
 
 Chemical composition : 1 equivalent of Iodine = 124 
 5 equivalents of Oxygen (each = 8) = 40 
 
 Consequently, chemical equivalent of lodic acid = 164. 
 
 124. Iodine combines in only one proportion with 
 oxygen. The product is iodic acid, a white, half-transpa- 
 rent solid, which is perfectly inodorous, and has a sharp, 
 sour, astringent taste. It is obta-ined by bringing protoxide 
 of chlorine (see 66, page 144) in contact with iodine, 
 and applying a gentle heat to the orange- colored vapors 
 which are thus formed. By this means vapors of iodine 
 and chlorine are given off, and a compound of iodine and 
 oxygen remains. No particular application is made of this 
 compound in the arts. 
 
 Combination of Iodine with Hydrogen Hydriodic Acid. 
 
 Chemical composition : 1 equivalent of Iodine =124 
 1 do. of Hydrogen = 1 
 
 Consequently, chemical equiv. of Hydriodic acid = 125. *~ 
 
 125. Iodine combines with hydrogen to hydriodic 
 acid. This combination is effected by the action of 
 
 14 
 
158 BROMINE. 
 
 moistened iodine on phosphorus. It is effected by 
 double elective affinity (see Intro, page 9). The oxygen 
 of the water combines with the phosphorus, and the hy- 
 drogen with the iodine. 
 
 Properties. It is a colorless gas, of a very pungent 
 and an intensely sour taste ; which reddens blue veg- 
 etable colors without bleaching them. Combined with 
 those substances called bases (see Intro, page 38) it forms 
 salts, of which some are now used in medicine. 
 
 126. Iodine combines yet with carbon, and in seve- 
 ral proportions with sulphur and phosphorus. It has like- 
 wise a strong affinity for boron, nitrogen, silicon, and the 
 metals. 
 
 Recapitulation of the Principal Binary Combinations of 
 Iodine. 
 
 C oxygen to iodic acid. 
 Iodine combines with < 
 
 ( hydrogen to hydriodic acid. 
 
 G. Bromine* 
 
 Chemical Equivalent = 75. 
 
 127. This is an element but recently discovered (in 
 1826) by Balard, a French chemist. It may, like iodine, 
 (to which it bears a strong analogy), be obtained from the 
 ashes of sea-weeds, or also from sea-water. 
 
 The washings of sea- weeds, or the liquor which remains in 
 salt-pans after sea water has been evaporated for the purpose 
 of obtaining common table salt, is mixed with a solution of 
 chlorine. This mixture being distilled by the application of a 
 gentle heat, the vapors must be made to pass over chloride of 
 lime. This salt, after absorbing the watery parts, will leave a 
 few drops of a blackish-red, volatile liquid, which is then the 
 pure bromine. 
 
 ^ 128. Properties of Bromine. At the common tem- 
 perature of the atmosphere it is a dark red fluid ; thin 
 
 * From a Greek word, signifying * a strong, disagreeable smell.' 
 
SILICON. 159 
 
 strata of it viewed through the light appear of a beautiful 
 hyacinth color. Its smell is exceedingly disagreeable, 
 and its taste sharp and nauseous. At a few degrees below 
 zero of Fahrenheit's thermometer, it congeals, and becomes 
 a grey, crystalline mass. It does not corrode the skin 
 permanently, is exceedingly volatile, boils at a tempera- 
 ture of 116 Fahrenheit, and gives off red vapors. It is 
 sparingly soluble in water ; but is readily dissolved in 
 ether, alcohol, and many of the fat oils. 
 
 Combinations of Bromine. 
 
 129. Bromine combines with oxygen to bromic acid, 
 a colorless, inodorous, sour liquid, which reddens litmus 
 paper ; and is composed of 
 
 1 equivalent of bromine = 75 
 and 5 equivalents of oxygen (each = 8) = 40 
 
 Consequently, chemical equiv. of bromic acid = 115. 
 
 With hydrogen it combines in 2 proportions, forming 
 hydrobromous and hydrobromic acid. The latter (the 
 most remarkable of the two), is a colorless gas, which 
 tastes and smells sour, is rapidly absorbed by water, and 
 emits white vapors. A solution of it in water has nearly 
 the same properties. 
 
 Bromine unites yet with chlorine, carbon, sulphur and 
 phosphorus. Through the intermission of hydrobromic 
 acid it unites with the metals potassium, tin, zinc, and 
 iron. 
 
 Recapitulation of the Principal Binary Combinations of 
 Bromine. 
 
 oxygen to bromic acid. 
 to 
 
 H. Silicon (Silicium). 
 
 Chemical Equivalent = 8. 
 
 130. This substance, (discovered by Berzelius in 
 1823) was formerly known only in combination with the 
 
160 SILICON. 
 
 fixed alkalies, potash, soda, lithia, lime, &c. (see Chap. 
 III). From these combinations, silicon, or silicium itself 
 is obtained by the action of heated potash. It is a dark 
 brown powder, without metallic lustre, which adheres easily 
 to other substances, and is a non-conductor of electricity. 
 It may be exposed to the most powerful heat without 
 fusing, and with the exception of fluor (of which we 
 shall soon speak), is not acted upon by any of the mineral 
 acids. 
 
 Combination of Silicon with Oxygen Silex. 
 
 Chemical composition : 1 equivalent of Silicon = 8 
 1 do. of Oxygen = 8 
 
 Consequently, chemical equivalent of Silicon = 16. 
 
 131. Silicon combines with oxygen only in one pro- 
 portion. The product of this combination, which is an 
 oxide of silicon, is called silex, silica, or silicioiis earth, 
 is the principal ingredient of all fossils in the mineral 
 kingdom. It is found almost in its simple form in rock- 
 crystal, flint and agate. In many other fossils it is found 
 combined with clay, lime, magnesia, &c. It has also 
 been discovered in plants, and animal matter, viz. : in the 
 enamel of the teeth, in bones, &c. 
 
 Silex is obtained by art in the following manner : One part 
 powdered quartz is melted in a crucible with three or four 
 parts of pure carbonate of potash (a salt hereafter to be de- 
 scribed) and when cooled, dissolved in dilute muriatic acid. 
 The precipitate which will be thus formed must be thoroughly 
 washed and dried until it is perfectly tasteless. 
 
 132. Properties of Silex. Silex obtained in the 
 manner just described, is a white, inodorous, tasteless pow- 
 der, which feels harsh when rubbed between the fingers, 
 and melts only in the highest degree of heat produced by 
 the most powerful galvanic batteries. It is perfectly in- 
 soluble in water, and, with the exception of fluoric acid, 
 in all the mineral acids. Combined with hydrogen it 
 forms a hydrate, which in nature occurs as a precious 
 stone, known by the name of opal. Silex is of inestima- 
 
SILICON. 161 
 
 ble application in the manufactory of glass, earthen ware 
 and porcelain. 
 
 Silicious earth (silica) occurs as principal ingredient in the 
 following fossils : 
 
 1. In Rock, or Mountain Crystal. Properties. It is color- 
 less, sometimes yellow, brown or black (as topaz) ; has a strong 
 glassy lustre, is perfectly transparent, and gives sparks on 
 steel. It abounds particularly in Madagascar, and the island 
 of Ceylon. 
 
 2. In Jlmathyst. Properties. It has a violet color, glassy 
 lustre, and is transparent. The finest amathysts are found in 
 Siberia, at the foot of the Ural mountains, and in Brazil. 
 
 3. In Common Quartz. Its color is a mixed white (milk- 
 quartz), gray, red (rose-quartz), brown (iron or flint quartz), 
 or blue (sapphire quartz). It forms a principal part of most all 
 mountainous masses, particularly of granite. It is used most 
 extensively in the manufactory of glass, porcelain and china- 
 ware. It is also a common building material, and is used in 
 the paving of streets and roads. (In France it is also employ- 
 ed for mill-stones). 
 
 4. In Flint. This is generally found in round masses, of a 
 grey, yellow, brown, or dark color, in layers of chalk or lime- 
 stone. It is used in the manufactory of English china (jlint- 
 ware), and glass (flint-glass). To the same species of stone 
 belong also Agate, Chalcedon, Jaspis, Carnelion, and Chryso- 
 prase. 
 
 5. In Pumice, a spungy, glassy stone, with a lustre like 
 mother of pearl, and a yellowish, sometimes green, color. It 
 is a volcanic product, forming great masses in the neighbor- 
 hood of volcanos, particularly in Italy, Iceland, Quito, and 
 Mexico. It is used for polishing ivory, marble, alabaster, parch- 
 ment, and leather. 
 
 6. In Sand. This is a product of the decomposition of 
 various kinds of stones and rocks, especially of stones which 
 abound in quartz, glimmer, and granite. It is found in all low 
 countries, in the beds of rivers, and on the sea-shore. It is of 
 almost universal application in the arts ; and is used in the 
 manufactory of glass, in the preparation of mortar, in the 
 grinding, polishing, and cleansing of articles ; in the manufac- 
 tory of bricks, in the casting of metals, &c. 
 
 Silicious earth is also contained in tripoli or rotten stone, a 
 yellowish white earthy substance, which is found in many 
 
162 FLUORINE. 
 
 countries, especially in the neighborhood of coal mines. It is 
 used for polishing metals, particularly brass. 
 
 Recapitulation. 
 Silicon combines with oxygen to Silex, or Siliceous earth. 
 
 I. Fluorine (1) 
 
 Chemical Equivalent (not ascertained). 
 
 133. Fluorine is a substance whose existence is not 
 yet satisfactorily proved. It was first (by Thenard, a 
 French chemist) supposed to exist in all three kingdoms 
 of nature, combined with the metals calcium, alumium, 
 sodium, and yttrium (see Chap. III). It is believed to be 
 analogous to bromine, iodine, and chlorine, and to form 
 with hydrogen fluoric acid, like chloric acid, iodic acid, 
 bromic acid, which are products of chlorine, iodine, and 
 bromine combined with hydrogen. 
 
 Fluoric Acid. 
 Chemical Equivalent =10. 
 
 134. Fluoric Jlcid (hydro-fluoric acid), is obtained 
 by the action of strong sulphuric acid on the well-known 
 substance fluor-spar. For this purpose the retort and re- 
 ceiver must be made of platinum or lead, glass vessels 
 being instantly corroded and destroyed by this acid, 
 which easily combines with silicon, the principal ingredi- 
 ent of glass. 
 
 Fluor-spar is found crystallized in various colors, green, red, 
 yellow, &c. It assists the fusion of earthy minerals in metal- 
 lurgical operation. If fluorine is a substance analogous to 
 chlorine, iodine, and bromine, then fluor-spar may be sup- 
 posed to be a fluoride of calcium. 
 
 135. Properties of Fluoric acid. It is a colorless 
 liquid of an exceedingly sharp, sour taste, a pungent, 
 penetrating smell, and a strong caustive power, which 
 when exposed to the atmosphere, emits white fumes. It 
 
FLUORINE. 1(33 
 
 absorbs water largely, is exceedingly volatile, boils at about 
 60 Fahrenheit, and does not congeal at 40 degrees below 
 zero of the same thermometer. Its vapors are very ob- 
 noxious to animals and all organic formations, which are 
 speedily destroyed by them. (This is the reason why the 
 investigation of its properties, and probably also its de- 
 composition into fluorine and hydrogen is so difficult, and 
 indeed, almost impracticable.) It may be mixed with wa- 
 ter in any proportion, the mixture giving off great heat. 
 If lime is thrown into it, heat and water are given off, and 
 a substance similar to fluor-spar (probably fluoride of cal- 
 cium) is produced. 
 
 Owing to its affinity for silicon (the principal ingredient 
 of glass) it has the peculiar power of operating on glass. 
 Plates of glass, covered with a composition of bees-wax 
 and oil of turpentine may be etched with it (or its vapors) 
 like a copper-plate. 
 
 Other Combinations of Fluorine. 
 
 136. There are but two more combinations of flu- 
 orine with other substances known viz. : with boron, 
 the product of which is fluoboric acid; and with silicon, 
 the product of which is fluoride of silicon. The former 
 is a colorless gas, of a pungent, suffocating smell, and a 
 strong, sour taste. It absorbs water, and produces white 
 fumes in contact with the atmosphere. The properties of 
 the latter are similar to those we have just mentioned. 
 
 Recapitulation, of the most important Binary Combina- 
 tions of Fluorine. 
 
 C Hydrogen to fluoric acid. 
 Fluorine combines with 2 Boron to fluoboric acid, 
 
 (J Silicon to fluoride of silicon. 
 
164 RECAPITULATION 
 
 EEC A PIT U LATION. 
 
 Questions for reviewing the most important Principles 
 contained in Chapter II. 
 
 A. QUESTIONS ON CARBON. 
 
 [ 72.] What other non-metallic elements are there, 
 besides the four gases, oxygen, hydrogen, nitrogen, and 
 chlorine ? What characterizing properties have these in 
 common with the gases. 
 
 73.] .What is the chemical equivalent of carbon, 
 f what substance does carbon form the principal in- 
 gredient 1 
 
 Where are diamonds principally found ? What is the spe- 
 cific gravity of diamond. What becomes of diamonds .when 
 submitted to the heat produced in the focus of a burning-glass, 
 or when burnt in pure oxygen ? What are the products of 
 the combustion of diamond ? 
 
 Describe the principal properties of plumbago. For what 
 is it used ? 
 
 What are the principal properties of Anthracite coal ? 
 Where is it chiefly found ? 
 
 What are the properties of Lehigh coal ? 
 
 What are the properties of black and brown coal ? 
 
 What does turf consist of? 
 
 How is vegetable charcoal obtained ? For what purpose is 
 charcoal used ? What is its most remarkable property ? Is 
 charcoal affected by heat, when submitted to its action in close 
 vessels ? What influence does charcoal exercise on other 
 bodies ? What does its mechanical structure enable it to do ? 
 How is animal charcoal obtained ? 
 
 Why has charcoal so different an appearance from diamond, 
 both substances being composed of the same element ? What 
 is the probable reason that diamond has not as yet been gen- 
 erated, or, in other words, why has not carbon been obtained 
 in its pure, crystallized state ? 
 
 [ 74.] In how many different proportions does carbon 
 combine with oxygen ? What two products of these com- 
 binations deserve our special notice ? 
 
 What is the chemical composition of carbonic oxide ? 
 
OP CHAPTER II. 165 
 
 [ 75.] Does carbonic acid occur in nature? How 
 then is it procured by art ? 
 
 How do you explain both processes ? 
 
 76.] What are the principal properties of carbonic 
 
 oxe 
 
 [ 77.] What is the chemical composition of carbonic 
 acid 1 Where is carbonic acid found ? By what other 
 processes is it continually produced ? 
 
 By what process may it be obtained by art 1 (Explain 
 the experiment represented in Fig. CII). 
 
 Explain this process. 
 
 [ 78.] What are the principal properties of carbonic 
 acid? 
 
 Why is there danger from burning charcoal in a confined 
 room ? 
 
 [ 79.] What is the cause of the agreeable pungent 
 taste, common to all sparkling, fermenting liquors ? 
 What is the pleasant, fresh taste of pump-water owing to ? 
 What then constitutes the principal difference between 
 river and pump water ? 
 
 What apparatus was formerly used for impregnating water 
 or any other liquid, with carbonic acid ? (Describe Fig. CIIIj. 
 
 [ 80.] Why must pure water not become turbid when 
 mixed with lime water ? 
 
 [ 81.] In how many different proportions does car- 
 bon combine with hydrogen ? What are the products ? 
 
 [ 82.] What is the chemical composition of sub-car- 
 buretted hydrogen ? 
 
 Where is this gas found ? Where else is it to be found? 
 By what means may it be procured for examination ? 
 
 [ 83.] What are the characterizing properties of sub- 
 carburetted hydrogen ? 
 
 What has been observed respecting the temperature which 
 is necessary to ignite an inflammable mixture of gases ? 
 What discovery did Dr Wollaston make ? To what idea was 
 
166 RECAPITULATION 
 
 Sir Humphrey Davy led by this discovery? How was this 
 idea realized ? 
 
 Describe Davy's safety lamp (Fig. CV). 
 
 Explain its operation. 
 
 By what experiment can you show that wire-gauze complete- 
 ly intercepts the flame of any burning substance ? What does 
 this serve to explain ? 
 
 [ 84.] What is the chemical composition of carbu- 
 retted hydrogen ? Is this compound found in nature, or 
 is it merely a product of art ? How is it obtained ? 
 
 Explain this process ? 
 
 [ 85.] What are the properties of carburetted hydro- 
 gen ? 
 
 [ 86.] What application is made of carburetted hy- 
 drogen, or olefiant gas ? 
 
 On what does the brilliancy of other gases depend ? How 
 does diamond burn in pure oxygen gas ? 
 
 By whom was gas light first employed for illumination? 
 Who introduced it first into England 1 From what was the 
 gas used in Europe first prepared ? How is the olefiant 
 gas used in America prepared ? By what process is the 
 oil decomposed and yields the gas ? Is the gas procured 
 from resin cheaper or dearer than that prepared from oil ? 
 
 Why has carburetted hydrogen been called olefiant gas ? 
 
 Are there any other combinations between hydrogen and 
 carbon, besides those you have mentioned ? 
 
 [ 87.] What is the chemical composition of cyano- 
 gen ? Does this gas occur in nature? By what means 
 then may it be obtained ? 
 
 [ 88.] What are the principal properties of cyano- 
 gen ? What is its most remarkable property ? 
 
 [ 89.] In how many different proportions does cyan- 
 ogen combine with oxygen ? What are the products ? 
 
 [ 90.] What is the chemical composition of Prussic 
 acid ? In what substances is this acid principally con- 
 tained ? By what process may it be obtained ? 
 
 How is this process explained ? 
 
OP CHAPTER II. 167 
 
 [ 91.] What are the properties of Prussic, or hydro- 
 cyanic acid ? 
 
 Can this acid be -very well preserved for any length of 
 time ? Why not 1 By what is its first stage of decompo- 
 sition marked ? What properties does it then lose ? 
 
 [^ 92.] In what respect does Prussic acid differ from 
 other acids you have thus far become acquainted with ? 
 
 What does it form in combination with those substances 
 called bases ? To what pole does it adhere, when it is 
 separated again from these substances by the agency of 
 galvanic electricity ? 
 
 By what experiment is it proved that Prussic acid is com- 
 posed of equal volumes of hydrogen and cyanogen ? What 
 follows from it, with regard to its composition by weight ? 
 
 [ 93.] With what other substances does cyanogen 
 yet combine ? What properties have all these compounds ? 
 What is a compound of cyanogen and sulphur called ? 
 What properties has it ? 
 
 [ 94.] In how many different proportions does carbon 
 combine with chlorine ? What are the compounds called ? 
 
 [ 95.] What is the chemical composition of sulphu- 
 rel of carbon 1 By what process can carbon and sulphur 
 be made to combine 1 (Explain the process represented 
 in Fig. CVIII). 
 
 [ 96.] What are the leading properties of sulphuret 
 of carbon ? Why must sulphuret of carbon be distilled at 
 so low a heat as 1 10 degrees Fahrenheit 1 What is the 
 specific gravity of sulphuret of carbon 1 What is its great 
 volatility, the cause of? 
 
 What are the principal binary and ternary combina- 
 tions of Carbon 1 
 
 B. QUESTIONS ON SULPHUR. 
 
 [ 97. What is the chemical equivalent of sulphur? 
 Where does sulphur occur ? Where does it abound ? 
 In what countries particularly has it been discovered ? 
 
168 RECAPITULATION 
 
 Where is sulphur yet contained ? 
 
 By what process can sulphur be purified from stones 
 and other earthy substances with which it is mixed ? 
 
 [ 98.] What are the principal properties of sulphur ? 
 What is its" specific gravity? How is roll-brim,stone, 
 obtained, which occurs in commerce 1 What becomes 
 of sulphur, when in a state of fusion it is poured into wa- 
 ter ? For what is it then used? What are the principal 
 applications of sulphur ? 
 
 [ 99.] In how many different proportions does sul- 
 phur combine with oxygen ? What are the products ? 
 Which of these combinations are the most remarkable 
 ones? 
 
 [ 100.J What is the chemical composition of sul- 
 phurous acid ? Where does this compound occur ? By 
 what means may it also be produced in a state of great 
 purity ? 
 
 How is this process explained ? 
 
 [ 101.] What are the principal properties of sulphu- 
 rous acid ? What do you understand by liquid sulphurous 
 acid ? How does this acid act upon vegetable colors ? 
 For what purpose is it chiefly used ? 
 
 [ 102.] What is the chemical composition of sulphu- 
 ric acid? What degree of oxygenation of sulphur is sul- 
 phuric acid ? Where does it occur ? 
 
 How many different sorts of sulphuric acid occur in 
 commerce ? What are their names ? From what is the 
 first, and from what is the second obtained ? 
 
 Explain the process by which the oil of vitriol is procured ? 
 
 How is hydro-sulphuric acid (or the common sulphuric acid 
 of commerce) manufactured ? 
 
 How is this complicated process explained ? (Let the pu- 
 pil explain the table on page 145). 
 
 [ 103.] What are the characterizing properties of 
 oil of vitriol ? What are the properties of sulphuric acid ? 
 
 [ 104.] What are the principal applications of sul- 
 phuric acid ? 
 
OF CHAPTER II. Jgg 
 
 [ 105.] In how many different proportions does sul- 
 phur combine with hydrogen ? What are the compounds ? 
 
 [ 106.] What is the chemical composition of sulphu- 
 retted hydrogen? 
 
 Where does it occur ? Where is it spontaneously pro- 
 duced (or given off) ? How may it be obtained for the 
 sake of experiment ? By what other means may it be ob- 
 tained in abundance ? How is this process explained? 
 
 [ 107.] What are the properties of sulphuretted hy- 
 drogen ? For what is sulphuretted hydrogen particularly 
 remarkable? By what substance is it decomposed? 
 What does this explain ? 
 
 [ 108.] With what other substances does sulphur 
 
 combine ? Is sulphur known to combine with nitrogen ? 
 
 What are the principal binary combinations of sulphur ? 
 
 C. QUESTIONS ON SELENIUM. 
 
 [ 109.] What is the chemical equivalent of seleni- 
 um ? Where does it occur ? What are its properties ? 
 
 In how many different proportions does it combine with 
 oxygen ? Name the compounds. What compounds does it 
 form with hydrogen ? In how many different proportions does 
 it unite with sulphur ? What are the compounds called ? 
 
 D. QUESTIONS ON PHOSPHORUS. 
 
 [ 110.] Has phosphorus as yet been found in nature 
 in its simple form ? From what is it chiefly obtained ? 
 
 Describe the process by which phosphorus is obtained. Ex- 
 plain this process. 
 
 [ 111.] What properties distinguish phosphorus ob- 
 tained in the manner you have ju?t described ? 
 
 Why is it necessary to keep phosphorus under water ? 
 What does phosphorus emit in contact with air ? 
 
 With what liquids does phosphorus readily combine ? 
 
 15 
 
170 RECAPITULATION 
 
 How much oxygen is phosphorus capable of taking up ? 
 For what is it used ? 
 
 [ 112.] In how many different proportions does phos- 
 phorus combine with oxygen 1 What are the products 
 called ? 
 
 [ 1 13.] What is the chemical composition of phos- 
 phoric acid ? Where does this composition occur ? How 
 may it be obtained by art 1 (Explain the experiment and 
 process represented in Fig. CX). 
 
 [ 114.] What are the characterizing properties of 
 phosphoric acid ? 
 
 [ 115.] In how many different proportions does phos- 
 phorus unite with hydrogen ? What are the products 
 thence obtained called ? 
 
 What is the composition of proto-phosphuretted hydro- 
 gen 1 What is the composition of per-phosphuretted hy- 
 drogen ? 
 
 [ 116.] By what process is per-phosphuretted hydro- 
 gen obtained? (Explain the experiment represented in 
 Fig. CXI). How is this process explained ? 
 
 What takes place when the gas, as it is extricated, is allow- 
 ed to escape from under the surface of the alkaline solution 
 into the air ? 
 
 [< 117.] What properties does phosphu retted hydrogen 
 
 How is proto-phosphuretted hydrogen produced ? To what 
 are its properties similar ? What takes place when the gas is 
 mixed with oxygen, and an electric spark is applied to the 
 mixture ? 
 
 What beautiful experiment may be made with water, phos- 
 phorus, zinc, and sulphuric acid ? How is this experiment ex- 
 plained ? 
 
 [ 118.] With what other substances does phosphorus 
 yet unite ? 
 
 What are the most important binary combinations of 
 Phosphorus ? 
 
OF CHAPTER II. 171 
 
 E. QUESTIONS ON BORON. 
 
 What is the chemical equivalent of boron ? 
 
 [ 119.] Is this element found in its simple state? 
 How then is it obtained ? 
 Explain the process. 
 What are the properties of boron ? 
 What is the product of the combustion of boron ? 
 
 [ 120.] What is the chemical composition of boracic 
 acid ? Are there any other combinations of boron with 
 oxygen ? In what form is boracic acid generally obtain- 
 ed ? Where is it found ? How may it be produced by 
 art? 
 
 Explain this process. 
 
 [ 121.] What are the properties of boracic acid ? 
 VViih what other substances does boron yet combine ? 
 
 F. QUESTIONS ON IODINE. 
 
 [ 122.] What is the chemical equivalent of iodine ? 
 Does this element occur in its simple form ? With 
 what substances is it found combined ? Where has it 
 lately been discovered? From what substances is it com- 
 monly extracted ? 
 
 Describe the process. 
 
 [ 123.] What are the principal properties of iodine ? 
 What sort of compound does it form in combination with 
 starch ? . For what purposes is it principally used ? 
 
 [> 124.] In how many proportions does iodine com- 
 bine with oxygen ? What is the product of this combi- 
 nation called ? By what means is it obtained ? 
 
 [ 125.] What is a combination of iodine with hydro- 
 gen called ? What is its chemical composition ? How is 
 this combination effected ? 
 
 What are the properties of hydriodic acid ? 
 
172 RECAPITULATION 
 
 [ 126.] With what other substances does iodine com- 
 bine ? 
 
 What are the principal binary combinations of Iodine 1 
 G. QUESTIONS ON BROMINE. 
 
 [$ 127.] What is the chemical equivalent of bromine ? 
 By whom was it discovered 1 How may it be obtained 1 
 Explain the process. 
 
 [ 128.] What are the principal properties of bromine ? 
 
 [ 129.] To what compound does bromine combine 
 with oxygen ? What is the chemical composition of this 
 compound ? In how many different proportions does it 
 combine with hydrogen ? What are the two compounds 
 called ? Which of the two is the most remarkable ? 
 What are its properties ? 
 
 With what other substances does bromine yet combine ? 
 
 What are the -principal binary combinations of Bromine 1 
 H. QUESTIONS ON SILICON (SILICIUM). 
 
 [ 130.] What is the chemical equivalent of silicon ? 
 By whom was this substance discovered? With what 
 other substances was it formerly known only to be com- 
 bined 1 By what means may it be separated from these 
 combinations? What are its properties? 
 
 [ 131.] In how many proportions does it combine 
 with oxygen ? What is the compound called ? What is 
 its chemical composition ? Where is it found ? 
 How may silex be obtained by art ? 
 
 [ 132.] What are the principal properties of silex? 
 What does it form when combined with hydrogen ? In 
 what consists the principal application of silex ? 
 
 In what fossils does silicious earth, or silex, principally oc- 
 cur ? [Let the pupil at first merely enumerate the fossils, 
 without describing them]. 
 
OF CHAPTER II. 173 
 
 What are the properties of Rock or Mountain Crystal ? 
 
 What are the principal properties of the rfmaihystt 
 
 What, those of common quartz? For what purposes is 
 common quartz used ? 
 
 What are the principal properties of Flint ? For what pur- 
 poses is it used ? To what species of stone belong Jlgate, 
 Choice 'on, Jaspis, Carnelion, Chrysoprast ? 
 
 What are the properties of Pumice? What sort of product 
 is it? Where is it found ? For what is it used? 
 
 What sort of natural product is sand ? Where is it found ? 
 For what purposes is it used ? 
 
 In what other substances is silicious earth contained ? What 
 sort of substance is tripoli, or rotten stone $ Where is it 
 found ? For what is it used ? 
 
 I. QUESTIONS ON FLUORINE. 
 
 [ 133.] Is the existence of Fluorine as yet satisfac- 
 torily proved ? By whom was this substance first suppos- 
 ed to exist 1 To what elements is it supposed to be anal- 
 ogous ? What substance is it supposed to form with 
 hydrogen ? 
 
 [ 134.] What is the chemical equivalent of fluoric 
 acid ? By what means \sjlvoric acid obtained 1 
 
 In what state is fluor-spar obtained ? What does it assist? 
 What is fluor-spar supposed to be ? 
 
 [ 135.] What are the properties of fluoric acid 1 
 What properties do its vapors possess ? What is this the 
 reason of? What takes place when lime is thrown into a 
 solution of it in water 1 
 
 What peculiar power does it possess in consequence of 
 its affinity for the principal ingredient of glass t How 
 may plates of glass be etched by fluoric acid 1 
 
 [ 136.] With what other substances does fluorine 
 yet combine? What are the products? What are the 
 properties of fluoric acid? What are the properties of 
 fluoride of silicon similar to? 
 
 What are the most important binary combinations of 
 Fluorine ? 
 
 15* 
 
174 OF THE METALS. 
 
 CHAPTER III. 
 
 OP THE METALS. 
 
 Preliminary Remarks. 
 
 137. Several attempts have been made to fix upon 
 the general characteristics of metals ; their properties, 
 however, are so various and relative, that we can only ap- 
 proximate more or less to a satisfactory result. With this 
 view on the subject it may be said that all metals are more 
 or less distinguishable by the following properties : 
 
 1. By a peculiar lustre, called the metallic lustre, which 
 is owing to their capacity of reflecting light. 
 
 2. By being generally good conductors of heat and 
 electricity. They are, moreover, commonly electro-posi- 
 tive bodies ; for when in a combined state with other sub- 
 stances, they are submitted to the action of a galvanic 
 battery (see Figs. LIX and LX, pages 40 and 4 1), these 
 combinations are again dissolved into their elements, and 
 the pure metal is always found to adhere to the negative 
 pole. (Compare the remarks in the Introduction, page 41 .) 
 
 3. By their opacity, to which hitherto but few appa- 
 rent exceptions have been found. 
 
 138. All metals, as far as our experience goes, are 
 simple bodies, or elements, all efforts to decompose them 
 having thus far proved ineffectual. They are in number 
 fortyone. 
 
OF THE METALS. 
 
 175 
 
 22. Iron, 
 
 23. Tin, 
 
 24. Lead, 
 
 25. Copper, 
 
 26. Zinc, 
 
 27. Bismuth, 
 
 28. Cobalt, 
 
 29. Antimony, 
 
 30. Arsenic, 
 
 31. Manganese, 
 
 32. Tellurium, 
 
 33. Titanium, 
 
 34. Cerium, 
 
 35. Uranium, 
 
 36. Columbium, 
 
 37. Tungsten, 
 
 38. Cadnium, 
 
 39. Chromium, 
 
 40. Molybdenum, 
 
 41. Vanadium. 
 
 1. Potassium, 
 
 2. Sodium, 
 
 3. Lithium, 
 
 4. Calcium, 
 
 5. Barium, 
 
 6. Strontium, 
 
 7. Magnesium, 
 
 8. Yttrium, 
 
 9. Alumium, 
 
 10. Glucinum (Berillium), 
 
 11. Zirconium, 
 
 12. Thorium, 
 
 13. Mercury. 
 
 14. Silver, 
 
 15. Gold, 
 
 16. Platinum, 
 
 17. Palladium, 
 
 18. Rhodium, 
 
 19. Iridium, 
 
 20. Osmium, 
 
 21. Nickel, 
 
 139. These metals vary from each other in color, 
 hardness, brittleness, ductibility, and fusibility. All of 
 them, however, have a greater or less affinity for oxygen, 
 and combine with it under the following circumstances : 
 
 1. When exposed to the atmosphere. 
 
 2. When brought in contact with water (which con- 
 tains oxygen), or any of the acids formed by the combina- 
 tion of oxygen. For this purpose concentrated sulphuric 
 and nitric acid are commonly used. 
 
 Most, metals when exposed to the air or to moisture lose 
 their metallic lustre, tenacity, and other apparent properties of 
 metals. They then crumble to powder, or soil the fingers, 
 having at the same time increased in weight. This change is 
 occasioned by the metals having combined with the oxygen of 
 the atmosphere or the water, or, in other words, by its having 
 been changed into an oxide (see classification of bodies, page 
 38). The increase of weight is of course proportions! to the 
 quantity of oxygen taken up in the combination. (See there- 
 mark 9, to the experiment represented in Fig. LXVI, page 54). 
 
176 OF THE METALS. 
 
 Among the various metals iron especially absorbs oxygen 
 from the air and from moisture ; and is by this means convert- 
 ed into a friable substance which collects on its surface. This 
 substance, which is an oxide of iron, is called rust. In order, 
 therefore, to prevent metals, and especially iron, from rusting, 
 it is necessary to keep them from the atmosphere. Sir Hum- 
 phrey Davy proposed also galvanic electricity as a preventive 
 against the oxydation of metals. Thus, copper is preserved 
 from combining with the oxygen of the atmosphere by bringing 
 it in contact with iron, only y^ part its size. The reason is 
 this. When copper andiron are placed upon one another, the 
 copper becomes negatively electric (see Nat. Phil. Chap. IX), 
 in which state it cannot attract the oxygen of the atmosphere, 
 which is itself a negatively electric substance ; but must repel 
 it, according to the laws of electricity. Steel instruments are 
 kept in silver paper, made of a mixture of tin and zinc, for a 
 similar reason. In a great many cases, however, galvanic 
 electricity favors the oxydation of metals. 
 
 140. Oxygen is not the only substance with which 
 metals are known to combine. They unite also, 
 
 1st. With Carbon. The products of these combina- 
 tions are called carburets. They do not occur in nature, 
 and are produced only by the fusion of the oxides of met- 
 als in contact with charcoal and other substances contain- 
 ing carbon. 
 
 2d. With sulphur. The result of these combinations 
 are termed sulphides. They occur abundantly in na- 
 ture, and form by far the most important ores of copper, 
 lead, tin, antimony, silver and quicksilver. 
 
 3d. With Chlorine. These combinations are called 
 chlorides, and are large products of nature. To this class 
 belong the chloride of Potassium, sodium, calcium, mag- 
 nesium, lead, &c. 
 
 4th. With Cyanogen, forming what are called cyanides. 
 These combinations are mere products of art. 
 
 5th. With Silicon, forming silicides. 
 
 6th. With Fluoride, forming fluorides, which are fre- 
 quently found in nature, particularly fluoride of calcium 
 (fluor spar), fluoride of yttrium, &c. 
 
 Besides these combinations, many metals unite yet with 
 
OF THE METALS. 177 
 
 hydrogen, selenium, phosphorus, boron, and iodine ; form- 
 ing respectively hydrates, selenides, phosphorides, borides, 
 and iodides. But we shall not stop to describe these, 
 intending to treat only of the most remarkable and useful 
 metallic combinations. 
 
 141. Alloys of metals. Metals frequently combine 
 with one another ; these combinations are called alloys ; 
 but the combinations of quicksilver with other metals have 
 received the special appellation of amalgams. The alloys 
 of metals have each a peculiar color, according to the 
 proportion of the metals in which they are compounded. 
 They are generally harder, though easier fusible than ei- 
 ther one of the metals of which they are compounded. 
 
 142. Of two metals which have different degrees of 
 fusibility and no particular chemical attraction for each 
 other, one may be made to melt (reduced to the liquid 
 state), while the other remains yet in the solid state. This 
 is, for instance, the case with the ores of copper and lead, 
 tin and copper, bismuth and cobalt, &c. On account of this 
 property, fusion is a means of refining ores, the more fusi- 
 ble metal being by this means liquefied and separated from 
 the other, which remains in a state of solidity. 
 
 143. Metals which easily melt are capable of ad- 
 vancing the fusion of other metals for which they have a 
 strong chemical affinity. Upon this property is founded 
 the process of soldering. This consists in uniting two 
 pieces of the same, or different metals, by means of a third 
 metal which is more fusible than either of them. To give an 
 
 EXAMPLE To solder tin ware, tinkers make use of a com- 
 position- (that is, of a solder) made of equal parts of tin and 
 lead. 
 
 Cast iron is soldered either by copper, silver, or tin, or also 
 by a mixture of copper and tin. 
 
 Copper and brass are soldered by a mixture of 5 parts of 
 silver, 6 parts of brass, and 2 parts of zinc. 
 
 Zinc is soldered by a mixture of lead and tin. 
 
 Platinum by fine gold. 
 
 Gold by a mixture of gold and silver ; and 
 
 Silver by a mixture of silver and copper. 
 
178 OF THE METALS. 
 
 144. Another process of art, founded on the natu- 
 ral attraction which exists between some of the metals, 
 is the covering of one metal by another. As an example 
 we will mention the tinning of vessels made of sheet iron ; 
 the gilding and silvering by means of amalgams with 
 which the substance to be gilded or silvered is merely 
 covered as with a pigment ; finally the plating of brass, 
 steel, or copper ware, with gold, silver, or platinum, where 
 one hard metal is rolled upon another, and remains upon 
 it merely by the natural force of attraction, without any 
 solder between them. 
 
 145. We have already said that few of the metals 
 are found in nature in their simple form ; but general- 
 ly combined with sulphur, oxygen, the acids, or earths, 
 in which state they are called metallic ores. They oc- 
 cur more or less in all quarters of the globe, but partic- 
 ularly in mountainous districts and in the neighborhood 
 of volcanos. They are generally bedded in strata, ex- 
 tending sometimes several miles in length, which by the 
 miners are called veins. Hence the common phrase of 
 the miners, ' to strike a new vein.' In these veins the 
 metals are most commonly found combined with those 
 substances we have just named, which on this account 
 are called mineralizers. Sulphur being most abundantly 
 found combined with the metals, is therefore called a min- 
 eralizer of them. But there are metals which are some- 
 times found in their simple form, and are then said to be 
 native metals. In this state gold and silver are frequently 
 found in North and South America. The gold of South 
 Carolina and Georgia, for instance, is so pure that without 
 alloy it cannot very well be worked. The silver mines of 
 Potosi, in South America, have been known to yield na- 
 tive silver, in lumps of forty or fifty pounds in weight. 
 
 146. The substances with which the metals are com- 
 bined (the mineralizers) being so different from each oth- 
 er in their chemical composition, it is evident that differ- 
 ent methods must be employed for different ores, in order 
 to extricate the pure metal from them. This process of 
 extracting the pure metal from the ore is called the reduc- 
 
OP THE METALS. 179 
 
 tion of the mdals. Three means are principally resorted 
 to for this purpose, 
 
 1st. The roasting of metals, which consists in placing 
 metallic ores upon a wood or coal fire, and heating them to 
 redness. By this means sulphur and other substances 
 which are mixed with the metals are separated. But there 
 are ores which do not require to be roasted. 
 
 2d. The smelting of ores, or the melting out of the met- 
 als from the ore. For this purpose the ore and charcoal 
 are mixed together in a furnace, and in this state intense- 
 ly heated, by which means the oxygen which is combined 
 with the metal, unites by elective affinity with the burning 
 charcoal, for which it has a most powerful affinity, setting 
 thereby the metal free. When the metal is thus extricated 
 from the ore, care is taken to cover its surface with a 
 melted mass of some earthy or alkaline substance, called 
 the flux, to prevent its subsequent oxydation in contact 
 with the atmospheric air. 
 
 3d. The refining of metals, which process has already 
 been described in 142, page 177. 
 
 147. Before we go on to treat of the different met- 
 als and their properties, it will be well to say a few words 
 on the similar properties of some of them, which enable 
 us to form them, as it were, into classes. Thus : 
 
 Potassium, sodium, lythium, calcium, barium, and stron- 
 tium, are generally called the alkaline metals ; because in 
 combination with oxygen they form respectively the fixed 
 alkalies, potash, soda, lithia, lime, baryta, and strontia. 
 These metals have all the strongest affinity for oxygen, 
 absorb it at all times from the atmosphere, and retain it at 
 the highest degree of heat. Their oxides, (the alkalies 
 which we have just enumerated) have all a hot, bitter, 
 caustic taste, are soluble in water, change blue vegetable 
 colors into green, and yellow colors into brown. 
 
 Magnesium, yttrium, allumium, glacinutn, zirconium, 
 thorium are called earthy metals, because in combination 
 with oxygen they form the earths magnesia, glucina,yttria, 
 alumia, zirconia, and thoria. 
 
 The nine metals, mercury, silver, gold, platinum, palla- 
 
180 POTASSIUM. 
 
 dium, iridium, osmium, and nickel, are commonly called the 
 noble metals ; because they do not easily undergo any 
 change or combine with oxygen. 
 
 Of the remaining twenty metals, iron, lead, tin, copper, 
 zinc, bismuth, cobalt, antimony, arsenic, manganese, telluri- 
 um, titanium, cerium, uranium, columbium, tungsten, cad- 
 mium, chromium, molybdenum, and vanadium, the first five 
 (iron, lead, tin, copper and zinc) are the most useful to 
 man, and are most generally employed in the arts. 
 
 We will now proceed to describe each metal and its 
 principal binary combinations in the same order as we 
 have just enumerated them. 
 
 A. OF THE six ALKALINE METALS, POTASSIUM, SODIUM, 
 LITHIUM, CALCIUM, BARIUM, AND STRONTIUM. 
 
 1. Potassium. 
 Chemical Equivalent = 40. 
 
 148. Potassium is a metal which was first obtained 
 by Humphrey Davy from the decomposition of a substance 
 called hydrate of potash (see the next section) through 
 the agency of a strong galvanic battery. It may also be 
 obtained in larger quantities, by heating hydrate of potash 
 with iron filings in a gun barrel. 
 
 The first process requires a galvanic battery composed of 
 at least 200 double plates, of 4 inches square. The hydrate 
 of potash must be slightly moistened (to increase the conduct- 
 ing power of electricity) and placed between two plates of 
 platinum connected with the two poles of the apparatus. The 
 substance will soon undergo fusion, when the oxygen of which 
 it is compounded, will separate at the positive pole, and the 
 pure metal (Potassium) will, in little globules, collect near the 
 negative pole of the battery. 
 
 For the decomposition of hydrate of potash by the action of 
 heated iron-filings, by which means potassium is obtained in 
 larger quantities, we are indebted to the combined researches 
 of Gay-Lussac and Thenard. 
 
POTASSIUM. 
 
 181 
 
 The apparatus employed for this purpose is represented in 
 Fig. CXII. 
 
 a 
 
 Fig. XCII. It consists of a very strong gun-barrel, a b c, 
 which must be curved as represented in the figure. Towards 
 one end c, of this barrel, it must be tapering to a smaller open- 
 ing, and the whole space between a and 6, must be covered 
 with a lute of infusible clay, which may be made of 5 parts of 
 sand and 1 of potters' clay. Into this barrel, between 6 and c, 
 introduce some clean iron-filings, and between a and 6, pieces 
 of solid hydrate of potash. The barrel must afterwards be 
 corked and in a provided with a safety tube, whose lower end (as 
 is represented in the figure) must be immersed into a vessel rf, 
 filled with mercury. To the smaller end of the barrel, a short 
 piece (e) of copper is accurately ground, which fits again into 
 a receiver/, made of the same metal. This receiver is also 
 provided with a safety tube g-, which dips below the surface of 
 mercury contained in the vessel h. A strong heat should 
 now be raised in the furnace, until the barrel between 6 and c, 
 becomes' white hot; the other parts of the barrel being all this 
 time kept cool by wet rags tied around them. The hydrate of 
 potash in the part a 6, of the barrel, may now be made to melt 
 by burning charcoal contained in a movable cage t, when in 
 consequence of the inclination of the barrel it will flow upon 
 the ignited iron filings, in the part 6 c, by which means a large 
 quantity of hydrogen (the product of the decomposition of 
 hydrate of potash), will be given off and escape through the 
 safety tube g. The movable cage must now be removed for a 
 little while, until the evolution of the gas ceases ; after which 
 
 16 
 
182 POTASSIUM. 
 
 it must be again put in its place ; and this operation must be 
 continued until no more gas is evolved. The hydrogen 
 of the hydrate of potash will then have escaped through the 
 safety tube, and the potassium in an oxidized state, will have 
 combined with the filings in the barrel. But as strongly 
 heated iron filings have a stronger affinity for oxygen than 
 potassium, an intense heat produced in the furnace will now 
 be sufficient to separate the potassium from them, and to 
 collect the metal nearly pure in the copper receiver f, and the 
 short tube e. 
 
 When these vessels are sufficiently cooled they must be re- 
 moved and filled with naphta, to give the potassium contained in 
 them a coating, which prevents its oxidation in contact with 
 atmospheric air. The naphta being now emptied again, the ves- 
 sels are stopped with cork until they are sufficiently cool for 
 the purpose of handling. The pure potassium may afterwards 
 be taken out and preserved in stopped phials, under rectified 
 naphta. 
 
 Asa small portion of potassium will always collect at the 
 lower end/, of the barrel, it will be well to stop the barrel it- 
 self with corks as soon as the copper barrel and receiver are 
 removed from it. When sufficiently cooled some naphta 
 must be suffered to pass through it, to prevent the oxidation 
 of whatever portion of the metal may have collected in it, 
 which may afterwards be collected and preserved as above 
 stated. 
 
 If at any time during the process gas should escape through 
 the safety tube d, instead of g, it is a sign that a piece of po- 
 tassium has lodged between c and e, to remove which it is only 
 necessary to apply some burning charcoal to the spot, which 
 will liquefy the potassium, and enable the process to go on 
 regularly. 
 
 The potassium thus obtained is less pure than that which is 
 procured by galvanic electricity ; but it is obtained in much 
 larger quantities and at a comparatively less expense. The 
 only difficulty consists in producing a sufficiently high heat for 
 the iron filings to decompose the oxide of potassium without 
 melting the barrel, and it is on that account that the part d c, 
 which is to be heated in the furnace, must be covered with a 
 lute of infusible clay. 
 
 149. Properties of Potassium. Potassium, obtained 
 by either of the processes just described, is at the ordinary 
 temperature of the atmosphere, of a soft, solid consistency, 
 and easily moulded between the fingers. Its color is that 
 
POTASSIUM. 133 
 
 of tin ; it has a strong metallic lustre, is perfectly opaque, 
 and a good conductor of heat and electricity. It is spe- 
 cifically lighter than water, (its specific gravity being only 
 0.865, that of water being I), fuses at 150 Fahrenheit, 
 and burns with a white flame when heated in contact with 
 air. It decomposes water at the common temperature of 
 the air, by combining with its oxygen, for which it has the 
 strongest affinity of any substance known. On this ac- 
 count (because it would absorb the oxygen from the at- 
 mosphere) it is necessary to keep it under naphta. 
 
 Combination of Potassium with Oxygen. 
 
 150. Potassium forms three different combinations 
 with oxygen, viz. : Sub-oxide, Protoxide, and Peroxide 
 of Potassium. The most remarkable among these is the 
 protoxide of potassium, commonly known by the name of 
 
 Potash, or Potassa. 
 
 It is composed of 1 equivalent of Potassium =40 
 1 equivalent of oxygen = 8 
 
 Consequently, chemical equivalent of Potash = 48. 
 
 This substance occurs in all three kingdoms of nature, 
 combined with the acids and in some of the fossils, such 
 as fluor-spar, basalt, granite, &,c. The purest potash is 
 obtained by burning potassium in dry air. It is of a 
 greyish-white color, hard, brittle, and easily soluble in 
 water. It is very caustic, and destroys animal and vege- 
 table substances. 
 
 The potash of commerce is obtained by the incineration 
 (burning, to ashes) of vegetable substances, wherefore it is 
 called the vegetable alkali. These ashes are afterwards boiled 
 down in pots, whence the name of Potash. The purest is call- 
 ed Pearl-ash. Potash unites with water to hydrate of potash 
 (caustic potash), which is easily dissolved in water, and com- 
 bined with fat or oil forms soap, a product of universal useful- 
 ness. 
 
 <> 151. The hydrate of potash is a white solid mass, 
 which melts at a red heat and emits white caustic vapors. 
 It is obtained from a solution of a salt called carbonate 
 
184 POTASSIUM. 
 
 of potash, in 10 or 12 parts of distilled water. A silver 
 plated kettle must be used for this purpose, as other metals 
 are affected by the solution. When the liquid is boiling 
 J part of fresh burnt marble or lime must be added in a 
 state of powder, and after being repeatedly stirred up with 
 it, the solution must be evaporated to dryness. 
 
 152. A solution of hydrate of potash is termed caus- 
 tic lye. It is either colorless, or of a pale yellow color ; 
 otherwise it is similar to the hydrate of potash. 
 
 Potash, hydrate of potash, and caustic lye, are used in 
 various processes in the arts, especially in the manufac- 
 tory of glass (see Chap. IV), in bleaching, dyeing and 
 calico-printing. 
 
 153. Potassium unites with chlorine to 
 Chloride of Potassium, 
 
 which is composed of 1 equivalent of potassium =40 
 1 do. of chlorine = 36 
 
 Consequently, chem. equiv. of chloride of potassium = 76. 
 
 In this state it is found in salt springs, and in sea water. 
 It may also be produced by introducing small pieces of 
 potassium into chlorine. The combination is so rapid 
 and intense as to cause a vivid inflammation, during which 
 each grain of the metal absorbs about 1 cubic inch of the 
 chlorine, by which means it is converted into a white saline 
 body, which has a bitter taste, and when mixed with 4 
 parts of water, forms a highly refrigerating mixture. 
 
 Potassium unites also with sulphur, selenium, and sodium. 
 The combination with sulphur, which is termed sulphuret of 
 potassium, is used in medicine. 
 
 Recapitulation of the Principal Binary Combinations of 
 Potassium. 
 
 l C sub-oxide } 
 
 \ oxygen to < protoxide >of 'potassium. 
 Potassium combines with / {peroxide ^ 
 
 / chlorine to chloride of potassium. 
 \ sulphur to sulphuret of potassium. 
 
SODIUM 185 
 
 2. Sodium. 
 
 Chemical Equivalent = 24. 
 
 154. Sodium is produced from hydrate of soda, in 
 the same manner in which potassium is obtained from hy- 
 drate of potash (see 149). It is a white metal, of the 
 color of silver, which has a strong metallic lustre, and is, 
 like potassium, a good conductor of heat and electricity. 
 It is opaque and solid at the common temperatures of the 
 atmosphere, soft at 160, and becomes liquid at from 180 to 
 190 degrees of Fahrenheit's thermometer. It decomposes 
 water without combustion ; but burns when only damped 
 with this liquid. Next to potassium, it has the strongest 
 affinity for oxygen of any substance known. 
 
 Combination of Sodium with Oxygen Oxide of Sodium, 
 or Soda. 
 
 Chemical composition: 1 equivalent of sodium ==24 
 I do. of oxygen = 8 
 
 Consequently, chemical equivalent of soda = 32. 
 
 155. Sodium combines with oxygen in three differ- 
 ent proportions, the products of which are sub-oxide, 
 protoxide, and peroxide of Sodium. The protoxide of 
 sodium, commonly called soda, occurs native in miner- 
 al seams or crust, (mineral alkali) combined with some of 
 the acids from the mineral and vegetable kingdoms. The 
 purest soda is obtained by the combustion of sodium. It 
 is a greyish, white mass, hard, brittle, less fusible and 
 volatile than potassium, and extremely caustic. It is solu- 
 ble in water and alcohol, and in short, possesses all the al- 
 kaline properties (see 147, page 179) in an eminent de- 
 gree. It is largely used in medicine and the arts. 
 
 156. A combination of chlorine with sodium, called 
 chloride of sodium, constitutes our 
 
 16* 
 
186 LITHIUM. 
 
 Common Table Salt. 
 
 Chemical composition: \ equivalent of sodium = 24 
 1 do. of chlorine = '36 
 
 Consequently, chemical equiv. of common salt= 60. 
 
 It occurs in great masses as parts of mountainous forma- 
 tions, or is found in deserts, where the whole ground is 
 sometimes covered with crystallized salt. In the deserts 
 of Barun, Darfur, Habesh, in the Highlands of Africa, 
 in Central Asia, near the Caspian Sea, in the Highlands 
 of Thibet, in Peru, and Chili. It is also contained in sea 
 water, from which it is obtained by a variety of processes, 
 but particularly by boiling and evaporating. It may also 
 be obtained in its purest form, by burning sodium in chlo- 
 rine ; or by heating sodium in muriatic acid gas. (Hence 
 it is by some chemists called muriate of soda). It is sol- 
 uble in water and in most liquids, crystallizes in four-sided 
 pyramids or cubes, and is one of the most indispensable 
 ingredients in the food of man. It is also used for a vari- 
 ety of chemical and medicinal purposes. 
 
 Recapitulation of the Principal Binary Combinations of 
 
 'incip 
 Sodii 
 
 lum. 
 
 Sodium J ortfe en to soda. 
 combines with \ chlorine to chloride of sodium or common salt. 
 
 3. Lithium. 
 Chemical Equivalent = Id 
 
 157. This substance is likewise obtained by gal- 
 vanic electricity, from lithia, an alkali which in 1817 has 
 been discovered in several rare metals, in Tourmaline (see 
 Natural Phil. Chap. X), and in some mineral waters. It 
 is a white, solid mass, of a crystalline fracture, and a very 
 caustic taste. It is sparingly soluble in water, and when 
 thrawn into alcohol burns with a purple flame. Com- 
 bined with oxygen it forms the 
 
CALCIUM 187 
 
 Oxide of Lithium, or Lithia, 
 
 which is composed of 1 equivalent of lithium = 10 
 1 do- of oxygen = 8 
 
 Consequently, chemical equivalent of lithia= 18. 
 
 This compound is soluble in water, with evolution of 
 heat, and possesses all the alkaline properties ( 147, 
 page 179). 
 
 4. Calcium. 
 
 Chemical Equivalent = 20. 
 
 158. This is another metal obtained by galvanic 
 electricity, from the well-known substance, lime. It is 
 white, solid, inflammable at the atmosphere, and decom- 
 poses water by combining with its oxygen, setting the hy- 
 drogen free. It combines with oxygen in two proportions. 
 The most remarkable of these combinations, 
 
 Protoxide of Calcium, or Lime, 
 
 is composed of 1 equivalent of calcium = 20 
 I do. of oxygen = 8 
 
 Consequently, chemical equivalent of lime = 28. 
 
 It is found in great abundance, combined with the acids 
 in all three kingdoms of nature. It is obtained pure by 
 exposing white marble, or calcareous spar to a red heat. 
 
 159. Properties of Lime. It is a soft, white mass, 
 requiring great degrees of heat for its fusion, but advan- 
 cing remarkably the fusion of most earthy substances ; 
 and is therefore said to be a flux. Its taste is caustic and 
 astringent. By absorption of moisture from the atmosphere, 
 or by the process of slaking (mixing it with water) it 
 becomes converted into an hydrate. 
 
 The use of Lime is very general and diversified. In archi- 
 tecture it is used for the preparation of mortar and for white- 
 washing ; in chemistry for the production of hydrate of pot- 
 ash, soda, and ammonia ; in the arts, for bleaching, dyeing, 
 
J 88 BARIUM. 
 
 and tanning. It is also used in sugar-refineries, and in the 
 manufactory of glass and parchment. Finally, it is employed 
 in domestic economy to absorb the moisture from fields. 
 
 Calcium combines also with chlorine to chloride of cal- 
 cium. When this substance is mixed with snow its refrig- 
 erating power is so great as to freeze mercury. 
 
 The chloride of lime, which is a combination of the oxide 
 of calcium with chlorine, will be described in the 4th chapter 
 among the salts. 
 
 Recapitulation of the principal Combinations of Calcium. 
 
 Calcium ^ oxygen to lime (Protoxide of Calcium). 
 combines with ^^ to ^ .^ ofcalcium ^ 
 
 5. Barium. 
 
 Chemical Equivalent = 70. 
 
 160. Barium is likewise produced by galvanic elec- 
 tricity from a substance called carbonate of baryta. It is 
 of a dark grey color, has. less lustre than cast-iron, is soon 
 oxidised when in contact with the atmosphere, acts vio- 
 lently on water (which is decomposed by it), and burns 
 when heated in the atmosphere, with a dark red flame. It 
 combines with oxygen in two different proportions, pro- 
 ducing respectively protoxide and peroxide of barium. 
 
 The protoxide of Barium (Baryta), also called Heavy 
 Earth, 
 
 is composed of 1 equivalent of barium = 70 
 1 do. of oxygen = 8 
 
 Chemical equivalent of protoxide of barium = 78. 
 
 161. Properties of Baryta. It is a greyish-white, 
 earthy substance, which does not melt at a common fire, 
 has a burning, caustic taste, and is very poisonous. When 
 thrown into water it becomes heated and deposites a white 
 powder (a hydrate). The solution, which is called baryta 
 
STRONTIUM. 189 
 
 water, is colorless, possesses all the alkaline properties, 
 and upon cooling or freezing forms regular crystals. 
 
 The peroxide of barium is a dirty-grey mass, suffering great 
 degrees of heat without being decomposed. 
 
 Barium combines also with chlorine, sulphur, and iodine, 
 forming respectively chloride, sulphuret, and iodide of 
 Barium. 
 
 Recapitulation of the principal Combinations of Barium. 
 
 combines with \ chlorine to chloride of barium. 
 v sulphur to sulphuret of barium. 
 
 6. Strontium. 
 
 Chemical Equivalent = 44. 
 
 162. Strontium is the last of the six alkaline metals, 
 which, like the rest, has been obtained by galvanic elec- 
 tricity. It has, like barium, a greyish white color, and 
 little metallic lustre. It combines with oxygen in two 
 proportions, forming Protoxide and peroxide of Strontium. 
 
 The protoxide of Strontium, Strontia, (so called 
 from the town of Strontia, in Argyleshire, where the na- 
 tive carbonate of strontia see Chap. IV was first 
 discovered in 1787) is generally found combined with sul- 
 phuric and carbonic acid. 
 
 It is composed of 1 equivalent of strontium = 44 
 1 do. of oxygen = 8 
 
 Consequently, chemical equivalent of strontia = 52. 
 
 It consists of a greyish white powder, which does not 
 melt at a common fire ; has a sharp, caustic taste (less 
 than baryta, but more than lime), and is dissolved in boil- 
 ing water to a colorless liquid, called strontia water, which 
 possesses all the alkaline properties. 
 
 Strontium combines yet with sulphur and chlorine to 
 sulphuret and chloride of strontium respectively. 
 
190 MAGNESIUM. 
 
 Recapitulation. 
 
 I 
 
 Strontium 
 combines with 
 
 ) sulphur to sulphuret 
 * chlorine to chloride 
 
 of strontium. 
 
 B. OF THE six EARTHY METALS, MAGNESIUM, YTTRIUM, 
 
 ALUMIUM, GLUCINUM (BERILLIUM), ZIRCONIUM, 
 
 AND THORIUM. 
 
 163. The existence of these metals is not so much 
 proved by actual experiment as by strong reasoning and 
 analogy. Their oxides were formerly known by the name 
 of earths, but from the experiments which have since been 
 made upon them, and the strong analogy which exists be- 
 tween them and the oxides of the alkaline metals, places 
 their metallic origin beyond a doubt or controversy. It is 
 on this account all modern chemists have, without an ex- 
 ception, treated of these substances as the oxides of the 
 metals we have just named, although they cannot be con- 
 verted to the metallic state by any ordinary process of 
 reduction ( 146, page 179) ; nor scarcely by any process 
 of science thus far known. They have all an insipid 
 taste, different from the fixed alkalies, which taste acrid ; 
 but neutralize the acids in the same manner as other 
 salifiable bases. 
 
 1. Magnesium. 
 
 Chemical Equivalent = 12, (doubtful). 
 
 164. Magnesium may be obtained by Voltaic elec- 
 tricity, or by the action of potassium on a substance called 
 chloride of magnesium. 
 
 When Voltaic electricity is employed, magnesium in con- 
 tact with mercury is exposed for a long time to the action of 
 the battery, until an amalgam is formed, which upon dry dis- 
 tillation (secluded from the atmosphere), during which the 
 quicksilver is partly converted into vapor, yields a dark-grey, 
 
MAGNESIUM. 191 
 
 metallic film. This is the metal magnesium. By the second 
 process, chloride of magnesium, a substance contained in sea 
 and well water, is heated in a platina crucible with about 10 
 parts of pure potassium. During this process the chlorine 
 combines by elective affinity with the potassium, setting the 
 magnesium free. 
 
 Magnesium obtained by either process can only be col- 
 lected in very small particles, scarcely sufficient for chem- 
 ical investigation. It has nevertheless been found to be a 
 white, 1 ductile substance, of great metallic lustre, which is 
 infusible in close vessels, at a very high temperature, but 
 burns when heated in contact with atmospheric air with a 
 red light, and with scintillation. It combines but in one 
 proportion with oxygen, the product being the oxide of 
 magnesium, commonly known by the name of 
 
 Magnesia, 
 
 whose chemical composition is supposed to be 
 
 1 equivalent of magnesium = 12 
 1 do. of oxygen = 8 
 
 Consequently, chemical equivalent of magnesia == 20, 
 
 although the exact proportion in which it is united with 
 oxygen is not yet ascertained. 
 
 165. The oxide of magnesium (Magnesia) is abun- 
 dantly distributed throughout nature, making part of ex- 
 tensive rock formations, and being also largely contained 
 in sea-water, from which it is obtained for commerce. In 
 its purest state it is best obtained by submitting carbonate 
 of magnesia, a substance with whose properties we shall 
 become acquainted in the 4th chapter, (o an intense red 
 heat, and it is on this account, by apothecaries, called cal- 
 cined magnesia (because the process of calcination con- 
 sists in burning bodies at an open fire). 
 
 Properties. It is a white, soft powder, without smell 
 or taste, infusible and insoluble in water, which is exten- 
 sively used in medicine. 
 
 Chloride of magnesium, which is a combination of magne- 
 sium with chlorine, is contained in sea and well water, and it 
 
192 GLUCINUM. 
 
 is from this substance that pure magnesia may be obtained 
 through the medium of potassium. 
 
 Magnesium combines also with sodium and with fluorine. 
 
 Recapitulation. 
 
 Magnesium < oxygen to oxide \ e 
 combines with \ chlorine to chloride J ***** 
 
 Glucinum (Berillium). 
 
 Chemical Equivalent = 20, (doubtful). 
 
 ^ 166. Glucinum is produced by the action of potassi- 
 um on a peculiar earth called Glucina (berillious earth). 
 
 When potassium is heated with this earth in close vessels, 
 it is changed into potash, and dark-colored globules are discov- 
 ered disseminated throughout the whole mass, which are the 
 metal Glucinum. 
 
 To this inference we are naturally led by the impossibility 
 of Potassium being converted into potash without absorbing 
 oxygen (potash being a compound of potassium and oxygen), 
 and the impossibility of its absorbing oxygen from any other 
 substance than from the earth glucina, since it is this sub- 
 stance alone with which it is brought in contact, atmospher- 
 ic air being excluded by the experiment being performed in 
 close vessels. Thus we have every certainty which reasoning 
 can give, that glucina is a combination of oxygen with some 
 metal which is its basis. This reasoning moreover is corrob- 
 orated by the fact that metallic globules do actually appear 
 disseminated through its mass when the experiment above 
 alluded to is made ; and to all this is yet added the strong 
 analogy which glucina bears to those substances which we 
 know to be oxides of metals, and which are reduced to the 
 metallic state by exactly the same operation, which alone, if all 
 experiments failed, would be sufficient to place the metallic 
 base of glucina almost beyond a doubt. 
 
 Properties. It is a dark-grey, granular powder, which 
 when polished assumes a metallic lustre. It does not be- 
 come oxydized at the common temperature of the atmos- 
 phere ; but burns when heated with great splendor. 
 
 Oxide of Glucinum, Glucina, Berillia, is known only 
 to exist in a few rare minerals. It is a white, light pow- 
 
YTTRIUM. ALUMIUM. 193 
 
 der, which adheres to the tongue like clay. It is insolu- 
 ble in water, but is readily dissolved in liquid potash or 
 soda. Its chemical equivalent is supposed to be 28. 
 Glucina combines also with sulphur and chlorine. 
 
 3. Yttrium. 
 
 Chemical Equivalent = 34, (doubtful). 
 
 167. This substance was likewise obtained by the ac- 
 tion of potassium on a substance called chloride of yttrium, 
 in the same manner as glucinum is obtained from glucina. 
 
 Properties. It consists of grey, metallic scales, which, 
 when polished, assume a dark lustre. It does not combine 
 with oxygen at low temperatures, but when heated burns 
 with a dazzling light. 
 
 Oxide of yttrium is found in a mineral (ytterby) and 
 in several other fossils in Sweden. It is a yellowish white 
 powder, inodorous, tasteless, insoluble in water, and infu- 
 sible at a common red heat. It combines with most of 
 the acids, forming a class of salts which are all more or less 
 distinguished by a sweetish taste, like sugar. Its chem- 
 ical equivalent is supposed to be 42. 
 
 4. Alumium. 
 
 Chemical Equivalent = 10, (doubtful). 
 
 168. This is another mineral, which has been pro- 
 duced by the action of potassium on chloride of alumium. 
 It is a grey, granular powder, with a metallic lustre like 
 that of tin ; when strongly heated it burns in contact with 
 atmospheric air, the residue being a white clay which 
 scratches glass. 
 
 Oxide of Alumium Alumia. 
 
 This compound of alumium with oxygen, is probably 
 composed of 1 equivalent of alumium = 10 
 1 do. of oxygen = 8 
 
 Chemical equivalent of alumia= 18. 
 17 
 
194 ZIRCONIUM, 
 
 169. Properties of Alumia. It is an abundant pro- 
 duct of nature, occurring either in its simple form, or as 
 a hydrate, or combined with the acids and earths as a 
 constituent part of rocks and alluvial depositions. 
 
 In its pure state it is contained in some of the gems, viz. : 
 In sapphire (blue) ; in the red oriental ruby, in topaz (yel- 
 low), amethyst (violet), in the emerald (green). The dif- 
 ferent kinds of clay used in the manufacture of glass and 
 porcelain contain hydrate of alumia in a greater or less 
 proportion. It is a loose, white powder, without taste or 
 smell, infusible at a common red heat, and insoluble in 
 water ; but has nevertheless a strong attraction for moisture. 
 It combines permanently with some dyeing stuffs, where- 
 fore it is used in calico printing. 
 
 .Alumium combines yet with chlorine to chloride of 
 alumium, with sulphur to sulphuret, and with fluorine to 
 fluoride of alumium. Neither of these compounds is of 
 much application in the arts. 
 
 Recapitulation. 
 
 C oxygen to alumia. 
 
 Jllumium combines with < chlorine to chloride of alumium. 
 ( sulphur to sulphuret of alumium. 
 
 5. Zirconium. 
 
 Chemical Equivalent not ascertained. 
 
 170. This metal has been obtained (by Berzelius) 
 by heating potassium with a salt called fluate of zirconia. 
 It is a black, dry powder, of a dark, metallic lustre, 
 which burns at a heat a little before redness, and is a bad 
 conductor of electricity. 
 
 Oxide of Zirconium, zirconia, has been found only in a 
 few minerals, the zircon (a precious stone) of Ceylon, and 
 the hyacinth from France. It is a fine, white powder, 
 without smell or taste, scratches glass, and is insoluble in 
 water. 
 
THORIUM. -MERCURY. 195 
 
 6. Thorium. 
 
 171. This metal was produced by the action of heat- 
 ed potassium on a substance called chloride of thorium, as 
 glucinum is produced from glucina. It is a grey, heavy 
 powder, which by pressure assumes a metallic lustre, does 
 not become oxidized in water, but burns when exposed to 
 a moderate heat with great splendor. The product of the 
 combustion, 
 
 Oxide of Thorium, or Thoria, which is also found in na- 
 ture, is a Norwegian fossil, called thoria, whence its name. 
 
 C. OF THE NINE NOBLE METALS, MERCURY, SlLVER, 
 
 GOLD, PLATINUM, PALLADIUM, RHODIUM, 
 IRIDIUM, OSMIUM, AND NICKEL. 
 
 1. Mercury. 
 
 Chemical Equivalent ?= 200. 
 
 172. This metal occurs comparatively but sparingly 
 in the mineral kingdom. But few countries possess quick- 
 silver mines. It is found either native (as virgin quick- 
 silver) , or combined in sulphur or mercurial ore. 
 
 This ore is reduced by heating it with iron filings or lime. 
 During the process the sulphur combines by elective affinity 
 with the iron or lime, setting the mercury free, which, by the 
 heat is volatilized, and passes over into a receiver, where in 
 contact with the colder sides of the vessel it is again condensed 
 into the. liquid form. 
 
 173. Properties. It is the only metal which is 
 liquid at the common temperature of the atmosphere. It 
 is perfectly tasteless, has a bluish white color and a strong 
 metallic taste. It freezes at 40 below zero of Fahren- 
 heit, and boils at 660 of the same scale. When congealed 
 it is malleable, and may be cut with a knife or hammered 
 into thin plates. It is so extremely volatile that its vapors 
 rise even at low temperatures, especially in a vacuum. On 
 
196 MERCURY. 
 
 this account all the thermometers and barometers (Nat- 
 ural Phil. Chaps. V and VI), are more or less incorrect by 
 the pressure of the vapors of mercury which rise in the 
 vacuum above it. 
 
 174. Mercury has the power of uniting to amalgams 
 with most metals, but more especially with gold, tin, silver, 
 zinc, lead, and bismuth, which it dissolves in minute 
 quantities. 
 
 This affords a means of extracting gold from other sub- 
 stances with which it is mixed in small quantities. Thus, 
 gold beaters are in the habit of shaking their dust with mercu- 
 ry, which amalgamate with the gold, from which the gold may 
 afterwards be obtained by heat, the quicksilver being volatil- 
 ized, while the gold remains in the solid state (compare 142, 
 page 177). Or it is also customary to press the amalgam thus 
 formed through a buckskin bag, which allows the mercury to 
 go through, but retains the gold. 
 
 Another application of the amalgam of gold is made in the 
 process of water gilding, which is performed by means of this 
 amalgam. An amalgam of quicksilver with silver is employed 
 in the same way to imitate plated ware. 
 
 The amalgam of tin is largely employed in silvering the 
 backs of looking glasses. For this purpose the quicksilver is 
 simply poured upon a sheet of tin foil, and the plate afterwards 
 pressed upon it, care being taken to place the plate upon the 
 amalgam in such a way as not to allow any air to remain be- 
 tween it and the metal. The plate remaining in this manner 
 pressed upon the amalgam, for a time not exceeding 48 hours, 
 the process in completed, and the amalgam adheres afterwards 
 to the plate merely by the adhesive attraction which exists 
 between these substances. The amalgam of tin and mercury 
 is also used for electrical machines, Leyden phials, and a num- 
 ber of processQs in the arts. 
 
 Combinations of Mercury with Oxygen. 
 
 175. Mercury combines with oxygen in two differ- 
 ent proportions, producing respectively protoxide and per- 
 oxide of mercury. 
 
MERCURY. 197 
 
 Protoxide of Mercury 
 
 is composed of 1 equivalent of mercury = 200 
 1 do. of oxygen = 8 
 
 Consequently, chem. equiv. of prot. of mercury = 208. 
 
 It is obtained when quicksilver is violently agitated in 
 contact with atmospheric air. By this means the quick- 
 silver is converted into a greyish black powder, which is 
 insipid and insoluble in water, and combines with a greater 
 portion of oxygen when gently heated in contact with at- 
 mospheric air. The compound then formed is 
 
 Peroxide of Mercury t 
 
 which is composed of 1 equivalent of mercury = 200 
 and 2 equivalents of oxygen (each = 8) = 16 
 
 Consequently, chem. equiv. of peroxide of mercury =216. 
 
 176. This compound, as we see from its chemical 
 composition, is composed of mercury combined with a 
 double quantity of oxygen, and is most readily obtained by 
 dissolving mercury in nitric acid and applying afterwards 
 a sufficient degree of heat to the solution to expel the acid. 
 
 Properties. It is of a dark red color, and but sparingly 
 soluble in water, to which it communicates the property of 
 turning blue vegetable colors into green. When distilled 
 in a glass tube it parts again with its oxygen and the met- 
 al is revived. 
 
 Both oxides of mercury combine with the acids to salts, 
 wherefore they are called salifiable bases (see Introduction 
 page 38). 
 
 Combinations of Mercury with Chlorine. 
 
 177. Mercury combines also in two proportions with 
 chlorine, forming Proto-chloride and Perchloride of Mer- 
 cury. 
 
 17* 
 
198 MERCURY. 
 
 Proto-Chloridc of Mercury ( Calomel) t 
 
 is composed of 1 equivalent of mercury = 200 
 and 1 do. of chlorine = 36 
 
 Consequently, chemical equivalent of proto-chlo- 
 
 ride of mercury = 236. 
 
 178. This compound is obtained directly by bringing 
 the mercury in contact with chlorine, at the common tem- 
 perature of the atmosphere. It is also formed when a solu- 
 tion of common salt is poured upon a solution of mercury in 
 nitric acid. The chlorine of which common salt is composed 
 (which is a chloride of sodium) combines then with the 
 mercury to a heavy, white powder which is precipitated ; 
 and must afterwards be washed and dried at a gentle heat. 
 The compound thus obtained forms that celebrated medi- 
 cine, known by the name of calomel, which is now of al- 
 most universal application, but was first employed and 
 prepared by Dr Bahneman, late Professor of Medicine in 
 Leipzig. 
 
 Per-Chloride of Mercury (Corrosive Sublimate) 
 
 consists of 1 equivalent of mercury = 200 
 2 equivalents of chlorine (each = 36) = 72 
 
 Consequently, chemical equivalent of per-chlo- 
 
 ride of mercury = 272. 
 
 1T9. This substance affords a powerful illustration of 
 the power of heat to increase chemical affinity (see Intro, 
 page 5). We have said in the last section that proto- 
 chloride of mercury is obtained by bringing chlorine and 
 mercury in contact at the common temperature of the at- 
 mosphere, but if this be done when mercury is heated, its 
 affinity for chlorine increases, in which case it combines 
 with a double proportion of chlorine, forming the com- 
 pound whose chemical composition we have stated at the 
 head of this section. Corrosive Sublimate is also prepar- 
 ed for medicinal purposes by subliming a mixture of 73 
 parts of a salt known by the name of sulphate of mercury 
 with 120 parts of common table salt (a chloride of sodium). 
 
MERCURY. 199 
 
 (The sulphate of mercury, which is a compound of sul- 
 phuric acid with mercury, is obtained by boiling to dry- 
 ness 50 parts, by weight, of mercury, and 70 of sulphuric 
 acid). 
 
 180. Properties. Corrosive sublimate thus obtain- 
 ed has a crystalline texture, is perfectly colorless, soluble 
 in water, and has a hot, acrid taste. When taken in its 
 pure state it is highly poisonous. One of the most distress- 
 ing symptoms accompanying the poisoning by corrosive 
 sublimate is the swelling of the glands and throat, which, 
 if it be taken in large quantities, terminates in suffocation. 
 It is nevertheless much used in medicine. 
 
 Combinations of Mercury with Sulphur. 
 
 181. Mercury unites yet with sulphur in two differ- 
 ent proportions, forming respectively proto-sulpJiuret and 
 bi-sulphuret of mercury. The first of these combinations 
 may be obtained by triturating together mercury and sul- 
 phur, or by passing a current of sulphuretted hydrogen 
 through water in which powdered chlorine is suspended. 
 It is composed of 1 equivalent of mercury = 200 
 1 do. of sulphur = 16 
 
 Its chemical equivalent therefore, is = 216. 
 Bi-sulphuretted Mercury 
 
 is composed of 1 equivalent of mercury = 200 
 and 2 equivalents of sulphur (each = 16) = 32 
 
 Consequently, chemical equivalent of bi-sulphu- 
 
 ret of mercury := 232. 
 
 182. This compound, also known by the name cin- 
 er, is, as we have had occasion to say before, the prin- 
 cipal ore from which mercury itself is obtained ; but it 
 may also be produced by art, by fusing together mercury 
 and sulphur, and subliming the compound. It is af a 
 beautiful red color, and is employed as a red pigment, 
 known by the name of vermilion. 
 
200 SILVER. 
 
 Recapitulation of the principal Binary Combinations of 
 Mercury. 
 
 ( oxygen to 
 
 ith< ( 
 
 combines with "Worine to 
 
 f sulph 
 
 ur to 
 
 2. 
 
 per-oxide 
 
 proto-sulphuret 
 per-sulphuret 
 
 Chemical Equivalent = 110. 
 
 183. This well-known metal is found native, or mix- 
 ed with chlorine, sulphur, copper, and other metals, in a 
 great many countries, but particularly in South America 
 and Mexico. It is of a beautiful white color and great 
 lustre, which is only surpassed by polished steel. It is very 
 malleable and possesses very great ductibility. It maybe 
 hammered into leaves of not more than one ten thousandth 
 part of an inch in thickness, and drawn out into wire of 
 the breadth of a hair. It is seldom (even by art) obtain- 
 ed in an entirely pure state, being generally alloyed with 
 a small portion of copper. Most silver contains also a 
 small quantity of gold (about ^ per cent), which for the 
 want of a cheap method of refining it, has until of late, 
 been suffered to remain with it*. The uses of silver for 
 coins, ornaments, instruments, vessels, &c, are sufficiently 
 known. It is eminently calculated for all these purposes, 
 on account of its unalterability, being only tarnished by 
 vapors of sulphur, and resisting oxidation even when ex- 
 posed to moisture in contact with heat. 
 
 Combinations of Silver. 
 
 184. Silver by uniting with oxygen, chlorine and 
 sulphur, forms the three respective compounds, oxide, chlo- 
 ride, and sulphuret of silver. The first of these combi- 
 nations, ' '''*- 
 
 * It has lately been extricated from the silver of some of the mines 
 in Saxony. 
 
SILVER. 201 
 
 Oxide of Silver , 
 
 is composed of 1 equivalent of silver = 110 
 and I do. of oxygen = 8 
 
 Its chemical equivalent, therefore, is = 118 
 
 It is obtained by adding lime-water to a solution of sil- 
 ver in nitric acid. It possesses an olive color, is insoluble 
 in water, and perfectly tasteless. 
 
 Chloride of Silver 
 
 is composed of 1 equivalent of silver = 110 
 1 do. of chlorine = 36 
 
 Consequently, chem. equiv. of chloride of silver = 146. 
 
 It is commonly known by the name of horn silver, and 
 obtained by adding a solution of common salt to one of 
 silver in nitric acid. The precipitate thus formed is the 
 chloride of silver, which at first is white, but gradually 
 becomes dark, and finally black, when exposed to the 
 rays of the sun. It is insoluble in water, and when heated 
 in a silver crucible, forms upon cooling, semi-transparent 
 crystals, similar to horn (hence the name of horn silver). 
 
 A mixture of chloride of silver, chalk and pearl-ash is used 
 for silvering brass. The brass must for this purpose be 
 well cleaned, and the mixture, a little moistened with water, 
 rubbed upon its surface. 
 
 Sulphurct of Silver 
 
 is composed of 1 equivalent of silver = 110 
 1 do. of sulphur = 16 
 
 Consequently, chem. equiv. of sulphuret of silver = 126. 
 
 This compound occurs in silver mines, but may also be 
 produced by art by placing thin plates of silver and sul- 
 phur upon one another, and heating them gently at a low 
 red heat. As this compound is much more fusible than 
 pure silver, the pure metal may be extricated from it by 
 heat. Another way of producing it is by passing sulphu- 
 retted hydrogen through a solution of silver in nitric acid. 
 
202 GOLD. 
 
 It is of a black color, but when fused is employed in the 
 manufactory of silver ornaments. 
 
 Recapitulation of the principal combinations of Silver. 
 
 C oxygen to oxide of silver. 
 
 Silver combines with 1 chlorine to chloride of silver, 
 (sulphur to sulphuret of silver. 
 
 3. Gold. 
 
 Chemical Equivalent 200. 
 
 185. Gold belongs to those metals which on account 
 of their being found in a native state, were known to the 
 remotest people of antiquity. It occurs either in its sim- 
 ple form, or combined with silver, tellurium, rhodium, 
 &c. Native gold is found in various shapes in Europe, 
 Asia, Jlfrica, and America, in Ceylon, Sumatra, Java, 
 Borneo and the Philippine Islands. 
 
 Properties. It is of a beautiful yellow color, and about 
 19 times heavier than water (its specific gravity being 19, 
 that of water taken for 1). Hammered out into thin 
 leaves it transmits the rays of the sun, the light passing 
 through it appearing green. It is more malleable and 
 ductile than any of the metals ; T \y of a grain of it may be 
 hammered out to cover 37 square feet of surface. Ac- 
 cording to Reaumure, a French philosopher, one grain of 
 gold may be drawn into a piece of wire 500 Paris feet 
 long, and 38 grains of the same metal are sufficient to 
 cover a piece of silver wire upwards of one thousand miles 
 in length! ! It is perfectly unchangable byjire, moisture, 
 or air, and is only acted upon by one solvent, which is a 
 mixture of muriatic and nitric acid (neither of these acids 
 does alone affect gold), which from this property of dis- 
 solving gold has been called aqua regia (king's water) ; 
 because the alchymists considered gold as the king of 
 metals. 
 
 Gold is used like silver for coins and ornaments, and 
 possesses the greatest value of any metal known. 
 
GOLD. 203 
 
 Gold from a state of solution may easily be revived by any 
 substance which has a strong affinity for oxygen, for which 
 gold has but a feebly affinity. Hence if a ribbon or some other 
 substance be moistened with a dilute solution of gold in aqua 
 regia, and afterwards exposed to a current of hydrogen, the 
 gold will be revived and cover the stuff. When the solution 
 is applied in regular figures, by means of a camel's-hair pen- 
 cil, it will afford a beautiful experiment, particularly to young 
 scholars. An etherial solution of gold, which is formed by 
 pouring sulphurous ether into a solution of gold, is employed 
 for gilding steel instruments, to preserve them from rust or 
 moisture. The solution is easily prepared by adding 2 ounces 
 of ether to one ounce of the solution of gold ; when the vessel 
 is thoroughly shaken and afterwards allowed to stand for a few 
 minutes, the ether which does not mix with the acid, and 
 which, on account of its being specifically lighter, will float on 
 top, may be poured off into another vessel. Any steel instru- 
 ment dipped into the etherial solution will instantly receive a 
 thin coating of gold. 
 
 Combinations of Gold. 
 
 186. Gold combines in two different proportions 
 with oxygen. The products are protoxide of gold, and 
 deutoxide of gold, or auric gold. Neither of these combi- 
 nations is used in the arts, neither is their nature and 
 composition precisely known or understood. The same 
 holds of the combinations of gold with chlorine (see Chlo- 
 ride of Gold, Chap. IV). Sulphuret of gold is obtained 
 like that of silver (see 184, page 201), by passing sul- 
 phuretted hydrogen through a solution of the metal. 
 
 The principal combinations of gold may therefore be 
 arranged as in the following table : 
 
 Gold combines "" J cMori ne to chloride of gold. 
 v. sulphur to sulphuret of gold. 
 
204 PLATINUM. 
 
 4. Platinum. 
 
 Chemical Equivalent = 96. 
 
 187. The Spanish philosopher, Antonio d'Ulod, ob- 
 served the ore of platinum, in 1736. An Englishman by 
 the name of Wood brought it first to Europe, where it 
 was analyzed, and found to contain besides, four different 
 metals, viz. Palladium, Rhodium, Iridium, and Osmium. 
 It has since been found in Russia, where it is used for 
 coin, for which it is admirably adapted on account of its 
 hardness and unalterability. 
 
 Properties. It is of a white color, somewhat resem- 
 bling steel, but has less lustre than silver. Like gold it is 
 not acted upon either by a common fire, moisture or air ; 
 nor by any of the acids alone, but is likewise dissolved 
 by a mixture of nitric and muriatic acid. When very 
 pure it is soft, ductile, and may be hammered out into 
 leaves, but cannot be drawn into suclnjine wire as either 
 gold or silver. It is a good conductor of heat and electri- 
 city, exceedingly difficult of fusion, and the heaviest of all 
 substances known (its specific gravity being 21 .5, that of 
 water taken for 1). 
 
 Besides the coining of money it is yet used for a variety 
 of scientific, particularly chemical purposes. It unites 
 with oxygen, chlorine and sulphur ; but the nature of these 
 combinations is not precisely ascertained. 
 
 Among the various applications of platinum in chemistry, 
 we will only mention a few, which will sufficiently serve for 
 an illustration. 
 
 1st. It is used for crucibles in all such cases where, in the 
 course of a chemical process some acid is to be employed which 
 would corrode or act upon some other metal, or which would 
 operate upon glass. 
 
 2d. It is used in the manufacture of a number of chemical 
 and physical apparatus, particularly in electric and galvanic 
 batteries, where it is used as a conducting wire. 
 
PLATINUM. 
 
 205 
 
 Fig. CXI II. 
 
 3d. In the construction of the flameless or aphlogistic lamp, 
 which is represented in the 
 adjoining figure. It consists 
 principally of a glass tube seve- 
 ral inches long, which must be 
 fitted to a small bottle or some 
 other low vessel (as represented 
 in the figure) by means of a 
 wooden cork, which has, besides, 
 another aperture C, for the pur- 
 pose of feeding the lamp with 
 alcohol. Into the glass tube is 
 inserted a coil of platina wire, 
 wound round a piece of wood, 
 which is shaped somewhat con- 
 ical (tapering), with its lower 
 end turned upwards. A piece of 
 wick establishes a communica- 
 tion between the alcohol and 
 the platina wire. 
 
 When the lamp is to be used the platina may be ignited 
 by the flame of a candle, which being afterwards blown out, 
 the wire will still remain red hot, and emit a feeble light, as 
 long as there is any alcohol remaining in the vessel. 
 
 This phenomenon is explained in the following way. When 
 the wire is ignited, its temperature is sufficiently raised to in- 
 flame the alcohol, which as we well know, is a highly combus- 
 tible substance ; but this being once done, the heat given out 
 by the burning alcohol is sufficient to keep the platina wire 
 red hot, even after its flarne is blown out. 
 
 Another application of platinum is made in the preparation 
 of platinum-sponge, for the purpose of producing instantaneous 
 light. Platinum-sponge is a substance which is obtained by 
 dissolving platinum in a mixture of nitric and muriatic acid, 
 and precipitating the metal from this solution by the addition 
 of some muriate of ammonia. This precipitate being after- 
 wards exposed in a crucible to a red heat, the acid and ammo- 
 nia are evaporated and the metal remains in a spongy mass, 
 which on that account has been called platinum-sponge. Its 
 most remarkable property consists in the manner in which it is 
 aifected by hydrogen gas, and which is not yet sufficiently ex- 
 plained. A jet of this gas being directed upon it, in contact 
 with, and at the common temperature of the atmosphere, the 
 platinum-sponge becomes immediately red hot, and ignites the 
 hydrogen. 
 
 18 
 
206 
 
 PALLADIUM. 
 
 Fig. CXIV. 
 
 Upon this property of 
 platinum-sponge, Professor 
 Dobereiner of the Univer- 
 sity of Jena, founded the 
 following simple apparatus 
 for obtaining instantaneous 
 light. Two glass vessels, 
 A and B, (see the figure) 
 are fitted to each other as 
 represented in the figure, 
 the vessel A, having a 
 tubular prolongation which 
 is ground air-tight into the 
 mouth of the vessel B. This 
 prolongation, which reaches 
 nearly to the bottom of the 
 vessel B, being surrounded 
 by small strips of zinc, and 
 sulphuric acid being poured into B, hydrogen gas will be evol- 
 ved, as in the experiment represented in Fig. LXX VIII, page 
 65, which by its pressure will force part of the liquid through the 
 tube into the upper vessel A. The remainder of the gas being 
 compressed by the weight of the water and the acid, a portion of 
 it will rush forth in a jet from the mouth of the pipe P, when the 
 stop-cock C, is turned open. This jet being directed upon some 
 grains of platinum-sponge, the latter will instantly become red 
 hot and ignite the hydrogen, which in its turn sets fire to the 
 wick of a small candle, which must be placed between the 
 mouth of the pipe and the platinum-sponge. 
 
 Besides the applications we have mentioned, platinum ad- 
 mits of many others, in Chemistry and Natural Philosophy, to 
 which the unalterability and ductability of the metal seem to 
 be particularly adapted ; and there can be no doubt but that its 
 uses would become as frequent as those of iron, if it were 
 found in larger quantities, and reduced from its ores by a more 
 simple process than is known in the present state of the sci- 
 ence. 
 
 5. Palladium. 
 
 Chemical Equivalent = 56. 
 
 188. Palladium, as we have observed in the last 
 section, is contained in raw platinum ore. It is also found 
 
RH O D I U M . I RI D I U M . OS M I U M. 207 
 
 combined with gold in Brazil. Its color is similar to that 
 of platinum. It is ductile and may be rolled into leaves, 
 or drawn into wire: It is less fusible than gold, tarnishes 
 when heated, but assumes again its original lustre when 
 submitted to higher degrees of temperature. It is acted 
 upon (dissolved) by the nitric, sulphuric, and muriatic 
 acids. It combines with oxygen and sulphur. The pro- 
 duct of the last combination, sulphuret of palladium, is of 
 a greyish white color, has a metallic lustre, and is brittle 
 and easily fusible. 
 
 (5. Rhodium. 
 
 Chemical Equivalent, (not ascertained). 
 
 189. This metal (likewise contained in platinum) 
 has but lately been found combined with gold. It is white 
 (like silver), hard, brittle, and infusible at a common red 
 heat. It is not acted upon by any acid, except when al- 
 loyed with another metal, but becomes oxydized when 
 calcined with potassium. 
 
 The oxide thus obtained is a hydrate of a brown color, and 
 astringent taste, which is dissolved by most acids, and com- 
 bines with the alkalies and earths in several proportions. 
 
 7. Iridium. 
 
 Chemical Equivalent (not ascertained). 
 
 190. Iridium is found united with osmium (see next 
 section) in form of small, black globules, from which it is 
 afterwards separated by the action of muriatic acid. It is 
 a white, heavy metal, which is not acted upon by any acid, 
 and is fusible only in small quantities by the agency of 
 powerful galvanic batteries. 
 
 8. Osmium. 
 
 Chemical Equivalent (not ascertained). 
 191. This metal is obtained by the same process as 
 
208 NICKEL. IRON 
 
 iridium. It is a greyish, black, or blue powder, which is 
 acted upon by nitric acid; small quantities of it burn 
 when transmitted to a red heat in contact with the atmos- 
 phere. The acid which is formed by the combustion of 
 the metal is soluble in water, and emits a peculiar odor 
 (from which the metal derived its name.*) 
 
 9. Nickel 
 
 Chemical Equivalent = 30. 
 
 192. Nickel is not an abundant product of nature, 
 and is generally united with cobalt or arsenic (the latter 
 combination is known in Commerce by the name ofspliss). 
 It has almost a silver-white color, a strong metallic lustre, 
 is not easily fusible, but ductile (when cold or warm), and 
 may be drawn into wire or rolled and hammered into plates. 
 It does not become oxydized in contact with the atmosphere 
 at common temperatures, but burns in pure oxygen. It is 
 attracted by the magnet, and is itself capable of receiving 
 and exhibiting magnetic power, in a degree less than iron 
 but greater than cobalt (see Nat. Phil. Chap. X). When 
 heated in contact with atmospheric air it is converted into 
 a dark powder> oxide of Nickel, which is yet possessed of 
 magnetic properties. 
 
 D. OF THE REMAINING METALS, IRON, TlN, LEAD, 
 
 COPPER, ZINC, BISMUTH, COBALT, ANTIMONY, AR- 
 SENIC, MANGANESE, TELLURIUM, TITANIUM, 
 CERIUM, URANIUM, COLUMBIUM, TUNGSTEN, 
 CADMIUM, CHROMIUM, MOLYBDENUM, 
 AND VANADIUM. 
 
 1. Iron. 
 
 Chemical Equivalent = 28. 
 
 193. No metal is of such importance to mankind as 
 * From a Greek word, signifying odor. 
 
IRON. 209 
 
 iron ; it is almost indispensable to civilization. Neither 
 gold nor silver are so intimately connected with the power 
 and prosperity of a people. By a wise distribution of Prov- 
 idence, it is most abundantly diffused throughout the whole 
 globe, and is found in all three kingdoms of nature. It is 
 generally met with in an oxydized state, native only in me- 
 teor stones* and in some of the fossils. It is of a bluish- 
 grey, sometimes white color, and susceptible of the high- 
 est polish. It is malleable and ductile, and may be drawn 
 into wire ; but cannot be beaten into very thin leaves, like 
 gold or silver. It is very hard and infusible ; but when 
 red hot it is soft and capable of receiving any form, by 
 hammering. It is strongly attracted by the magnet, and 
 is itself capable of receiving all magnetic virtues. 
 
 The native magnet or load-stone, is an ore which is known 
 by the name of magnetic iron ore. It occurs crystal- 
 lized, in regular octahedrons, or in crystalline masses, but 
 sometimes also in an earthy state. When crystallized it has 
 a strong metallic lustre, and a greyish black color. Its pe- 
 culiar properties have been described in Natural Philosophy, 
 Chapter X. 
 
 Combinations of Iron with Oxygen, Chlorine and Sulphur. 
 
 194. Iron has a strong affinity for oxygen, and forms 
 with it two definite oxides protoxide and per-oxide of 
 iron. The chemical composition of the 
 
 Protoxide of Iron 
 
 is 1 equivalent of iron = 28 
 1 do. of oxygen = 8 
 
 Consequently, chemical equiv. of protoxide of iron = 36. 
 
 * Meteor stones are such as have come down through the atmos- 
 phere. Their origin is not precisely ascertained. Some philosophers 
 believe they are of cosmic origin ; that is, so many little globes, re- 
 volving like our earth around a common centre, which is the sun. 
 The authorities for this opinion are Biot, Chladni, and all German 
 mineralogists. 
 
 18* 
 
210 IRON. 
 
 Per-oxide of Iron 
 
 is composed of 1 equivalent of iron = 28 
 1 do. of oxygen = 12 
 
 Consequently, chemical equiv. of per-oxide of iron = 40. 
 
 The Per-oxide is obtained fro m a solution of iron in 
 nitric acid, which must afterwards be boiled and precip- 
 itated by ammonia. It is of a red color and not attracted 
 by the magnet. The protoxide may be obtained by sepa- 
 rating part of the oxygen from the per-oxide which is done 
 by passing hydrogen over the per-oxide, at a temperature a 
 little below red heat. It is blue, ignites spontaneously 
 when exposed to the atmosphere, and is attracted by the 
 load-stone, though feebler than raw iron. When iron is 
 made red hot in contact with atmospheric air, black oxide of 
 iron is formed., which is an indefinite compound of iron 
 with oxygen (a mixture of protoxide and per-oxide) and an 
 abundant product of nature. 
 
 195. Iron unites also with chlorine in two propor- 
 tions. The respective products are proto-chloride and per- 
 chloride of iron. 
 
 Proto-Chloride of Iron 
 
 is composed of 1 equivalent of iron = 28 
 1 do. of chlorine = 36 
 
 Consequently, chem. equiv. of proto-chloride of iron = 64. 
 Per-Chloride of Iron 
 
 is composed of 1 equivalent of iron = 28 
 1^ do. of chlorine = 54 
 
 Chemical equivalent of per-chloride of iron = 82. 
 
 Proto-chloride of iron is obtained from a solution of iron 
 in muriatic acid, which should be evaporated to dryness 
 and then ignited (secluded from the atmosphere). The 
 product thus obtained is of a grey color, has a metallic lustre 
 and scaly texture. The Pcr-chloride of iron is produced 
 by burning iron wire in chlorine. It is a brown substance, 
 
IRON. 211 
 
 of great lustre. Both chlorides are used in dyeing the 
 per-chloride is also employed in medicine. 
 
 196. The sulphurets, proto-sulpliurets and bi-sulphu- 
 ret of iron are products of nature. The bi-sulphuret, par- 
 ticularly, is an abundant natural product, and is known by 
 the name of iron pyrites. It is of a yellow bronze color, 
 somewhat similar to gold (for which it is sometimes mis- 
 taken by those unacquainted with mineralogy) and is 
 often found in crystals. It has not as yet been produced 
 by art, and when heated becomes converted into proto- 
 sulphuret of iron, by losing half its proportion of sulphur. 
 The proto- sulphuret may also be produced by rubbing sul- 
 phur on red-hot iron. The sulphuret will fall down in 
 drops, which upon cooling are slightly attracted by the 
 magnet. 
 
 Proto-Sulphuret of Iron 
 
 is composed of 1 equivalent of iron = 28 
 1 do. of sulphur = 16 
 
 Consequently, chemical equivalent of proto-sul- 
 
 phuret of iron = 44. 
 
 Bi-Sulphuret of Iron 
 
 is composed of 1 equivalent of iron = 28 
 2 do. of sulphur =32 
 
 Consequently, chem. equiv. of bi-sulphuret of iron = 60. 
 Combination of Iron with Carbon, (Steel). 
 
 197. When malleable iron is surrounded by pow- 
 dered charcoal, and for a length of time exposed to a red 
 heat, part of the carbon, to the amount of about T i^ part of 
 the weight of iron, unites with the iron and forms the well- 
 known substance, steel. This product of art, which was 
 already known to the ancients,* is by far more elastic, hard 
 and sonorous than iron itself. In order to adapt it to the 
 
 * The Jews, under Moses, knew the manufactory of steel; but in 
 the Trojan war, 1200 years before Christ, copper arms were used. 
 
212 LEAD. 
 
 variety of purposes for which it is used, it must undergo the 
 process of tempering , which consists in heating it to a certain 
 point. According to the different manners in which steel 
 is manufactured, and the iron ore employed for that pur- 
 pose, it is called rough steel, blistered steel, or cast steel ; 
 all which are articles of commerce. The uses of steel for 
 the manufactory of surgical instruments, razors, pen- 
 knives, scissors, knives, forks, small and broad-swords, 
 domestic implements, carpenters' and other tools, pens, 
 balances (of watches), musical instruments, &,c, are well 
 known, and justify the assertion made in the beginning 
 of 193. 
 
 Recapitulation of the principal Combinations of Iron. 
 
 C protoxide } 
 
 oxygen to < per-oxide > of Iron. 
 ( black oxide 3 
 
 spi, i 
 
 ^ carbon to Steel. 
 
 2. Lead. 
 
 Chemical Equivalent = 104. 
 
 ^ 198. This well known metal occurs abundantly 
 (though not often in a native state) in the mineral king- 
 dom, and was, on account of its easy production from the 
 ores, known to almost all people of antiquity. In its pure 
 state it is of a bluish-grey color, and when recently cut has 
 a strong metallic lustre. It is very soft and ductile, but 
 on account of its small cohesive attraction cannot very well 
 be drawn into wire, but may be hammered out into plates. 
 It leaves a stain on paper or wood, and a faint, disagreea- 
 ble smell on the fingers. It boils when exposed to a red 
 heat, and emits vapors which are very injurious to health. 
 It is extensively used in the manufacture of shot, sugar 
 of lead (see Chap. IV), and in the process of cupellation 
 (see the next section). 
 
LEAD. 213 
 
 Combination of Lead with Oxygen, Chlorine, and 
 Sulphur. 
 
 199. Lead combines in four different proportions 
 with oxygen. The products are sub-oxide of lead (ashes 
 of lead) ; protoxide of lead (the massicot of commerce) ; 
 deutoxide of lead (red lead) ; and per-oxide of lead. 
 
 Chemical Composition of the Oxides of Lead. 
 Sub-oxide of Lead 
 
 is composed of 1 equivalent of lead = 104 
 i do. of oxygen = 4 
 
 Consequently, chem. equiv. of sub-oxide of lead = 108. 
 Protoxide of Lead 
 
 is composed of 1 equivalent of lead = 104 
 
 1 do. ofoxygen= 8 
 
 Consequently, chem. equiv. of protoxide of lead =112. 
 Deutoxide of Lead 
 
 is composed of 1 equivalent of lead = 104 
 and 1 do. of oxygen = 12 
 
 Consequently, chem. equiv. of deutoxide of lead = 116. 
 Per-oxide of Lead 
 
 is a product of 1 equivalent of lead = 104 
 
 2 do. ofoxygen= 16 
 
 Consequently, chern. equiv. of per-oxide of lead = 120. 
 
 All these oxides may be obtained, though in an impure 
 state, by heating lead in atmospheric air, or by the action 
 of nitric acid. They have the peculiar property of com- 
 bining with most metals, except silver, gold, and platinum ; 
 and are on this account used for purifying gold and silver. 
 
 The metal which is to be purified is wrapped up in a sheet 
 of lead, and melted in a crucible. By this process, which is 
 called cupellation (see 198), the lead which is melted first 
 
214 TIN. 
 
 sinks to the bottom and carries along with it all the baser met- 
 als with which it combines. 
 
 The protoxide of lead, or massicot of commerce, is obtained 
 by fusing lead in open vessels, and continuing the heat until it 
 has assumed a uniform yellow color. When this substance is 
 again partially melted, it is called litharge, which however is 
 less pure than the massicot. 
 
 The deutoxide of lead is known in commerce by the name 
 of red lead, and is used as a pigment, and in the manufactory of 
 glass. It is obtained by exposing massicot to a moderate heat, 
 presenting a large surface to the atmosphere. At a tempera- 
 ture equal to red heat it parts again with a portion of its oxy- 
 gen and is converted into protoxide. When nitric acid 
 is poured upon the deutoxide, it is again partly converted into 
 a protoxide, which is dissolved by the acid, from which it ab- 
 sorbs a further portion of oxygen, and is then precipitated in 
 form of a dark brown powder, which is the per-oxide. 
 
 Chloride of Lead is produced by adding common salt to a so- 
 lution of lead in nitric acid. It has a sweet taste, and when 
 fused has the appearance of horn wherefore it is called 
 horn lead. It is composed of 1 equivalent of lead = 104 
 
 1 do. of chlorine = 36 
 
 Consequently, chemical equivalent of chloride of lead = 140. 
 
 Sulphuret of Lead (galena) is an abundant product of nature. 
 It is less fusible than lead, and constitutes the ore from which 
 pure lead is commonly obtained. 
 
 Recapitulation of the principal Combinations of Lead. 
 C sub-oxide 1 
 
 Lead 
 
 combines with deutoxide 
 
 chlorine to chloride of Lead. 
 sulphur to sulphuret of Lead. 
 
 3. Tin. 
 
 Chemical Equivalent = 59. 
 
 200. Tin is also one of the oldest metals. It 
 was known to the Phenicians, who brought it from Spain 
 and England. It was wrought in the times of Moses, al- 
 though it is not a very abundant product of nature. It 
 
TIN. 215 
 
 occurs either as an oxide or a sulphuret. In its pure state 
 its color resembles that of silver ; its hardness is between 
 lead and gold. It may be cut with a knife, is very duc- 
 tile, may be hammered into leaves or drawn into wire, and 
 leaves, like lead, a faint, disagreeable smell on the fingers. 
 When bent forward and backward it makes a crackling 
 noise ; but loses this property when frequently repeated. 
 It is used for the manufactory of vessels, plates, pots, ket- 
 tles, and for tinning all kinds of sheet-iron ware. 
 
 Combinations of Tin with Oxygen, Chlorine and Sulphur. 
 
 201. Tin has a strong affinity for oxygen, and com- 
 bines with it in two proportions, forming Protoxide and 
 Per-oxide. 
 
 Chemical Compositions. 
 Protoxide of Tin 
 
 consists of 1 equivalent of tin = 59 
 1 do. of oxygen = 8 
 
 Consequently, chemical equiv. of protoxide of tin = 67. 
 Per-oxide of Tin 
 
 is composed of I equivalent of tin = 59 
 2 do. of oxygen = 16 
 
 Chemical equivalent of per-oxide of tin = 75. 
 
 Both products may be obtained by heating tin in con- 
 tact with the atmosphere, or by the action of nitric acid on 
 the metal. 
 
 When tin is fused, and for a long time in the liquid state, ex- 
 posed to the atmosphere, it becomes converted into a grey 
 powder, which is the protoxide. When this is again heated 
 in contact with air, it combines with a further portion of oxy- 
 gen, and is changed into the per-oxide. 
 
 The Per-oxide has a light yellow color, becomes yellow 
 at a red heat, is infusible, and insoluble in water, and 
 unites by double affinity (see Intro, page 9) with the al- 
 kaline earths. Oxide of tin, united with that of lead, is 
 
216 COPPER. 
 
 used in the manufactory of brass (see 203), and for pol- 
 ishing hard substances, such as glass, crystal, stones, &c. 
 Proto- Chloride of Tin is obtained by dissolving tin-filings in 
 muriatic acid. It is grey, half-transparent, and soluble in wa- 
 ter. Per-chloride of tin is obtained by heating tin-filings with 
 chlorine. It is a thin, volatile liquid, which inflames oil of 
 turpentine and emits white fumes when exposed to the atmos- 
 phere. 
 
 Proto-chloride of Tin 
 
 is composed of 1 equivalent of tin = 59 
 1 do. of chlorine =36 
 
 Consequently, chemical equiv. of proto-chloride of tin = 95. 
 Per- Chloride of Tin 
 
 is composed of 1 equivalent of tin = 59 
 2 do. of chlorine = 72 
 
 Consequently, chemical equiv. of per-chloride of tin = 131. 
 
 202. Of the two sulphurets of tin (Proto-sulphuret 
 and sulphuret) the proto-sulphuret is produced by a fusion 
 of tin and sulphur. It is blue and brittle. The sulphu- 
 ret is produced by heating per-oxide of tin with sulphur- 
 It is used for giving a beautiful yellow color to gold. 
 
 Recapitulation of the principal Combinations of Tin. 
 
 comb^with 
 
 4*r.t. 
 
 4. Copper. 
 
 Chemical Equivalent = 72. 
 
 t203. Few metals have so long been known to man, 
 ave been wrought at so early a period, as copper. (The 
 ancients brought it from the island of Cyper). It is found 
 in a metallic state, connected with other substances, espe- 
 
COPPER. 217 
 
 cially sulphur. It is red, elastic, sonorous, and when pure 
 has a strong metallic lustre. It has a faint, disagreeable 
 smell and taste, and is less coherent than iron. It is a 
 good conductor of heat, and the best conductor of electri- 
 city. It is less fusible than silver, more so than gold, 
 becomes volatile at high degrees of heat, burns with a 
 green flame, becomes oxidized in contact with a damp at- 
 mosphere, and covered with a green crust, which is very 
 injurious to health. It is used for the coverings of roofs, 
 for pans and pipes in breweries, sugar refineries, and soap- 
 manufacturies. It is employed also in the construction of 
 boilers for steam-engines, for fastening vessels, and a va- 
 riety of other useful purposes. One of its chief applica- 
 tions consists in uniting it with zinc in the manufactory 
 of brass and tombac ; and with different proportions of tin 
 for the casting of bells, and in the preparation of gun and 
 speculum metal. (The latter is used for the construction 
 of reflecting telescopes, in the manufactury of optical in- 
 struments). 
 
 Combinations of Copper with Oxygen, Chlorine, and 
 Sulphur. 
 
 204. We know of two combinations of copper with 
 oxygen. Both are products of nature, but may be obtain- 
 ed by burning copper, in a state of minute division, in at- 
 mospheric air. The protoxide is red and melts at a red 
 heat ; the deutozide is black and tasteless. 
 
 The protoxide consists of 1 equivalent of copper = 72 
 and 1 do. of oxygen = 8 
 
 Chemical equivalent of protoxide of copper = 80. 
 
 The deutoxide is composed of 1 equivalent of copper = 72 
 
 2 do. of oxygen = 16 
 
 Chemical equivalent of deutoxide of copper = 88. 
 
 205. Proto-chloride and per-chloride of copper are 
 obtained by introducing copper filings into chlorine. The 
 filings will spontaneously take fire, and both compounds 
 are at once produced, the proto-chloride in a solid state, 
 and the per-chloride in form of a powder. The proto- 
 19 
 
218 ZINC 
 
 chloride is a yellowish substance, similar in appearance to 
 resin, easily fusible, but insoluble in water. The per- 
 chloride is a brown powder, which, when it has absorbed 
 moisture from the air, turns green. Spirits of wine, in 
 which per-chloride of copper has been dissolved, burns 
 with a beautiful green flame, on account of which it is 
 used in fire-works and for theatrical purposes. 
 
 Proto-Chloride 
 
 is composed of 1 equivalent of copper = 72 
 1 do. of chlorine = 36 
 
 Consequently, chemical equivalent of proto-chlo- 
 
 ride of copper = 108. 
 
 Per-Chloride of Copper 
 
 is composed of 1 equivalent of copper = 72 
 2 do. of chlorine = 72 
 
 Chemical eqvivalent of per-chloride of copper = 144. 
 
 The Sulphurets of copper (proto-sulphuret, and bi-sul- 
 phuret) are abundant products of the mineral kingdom. 
 The former is found combined with other sulphurous met- 
 als, the latter has been discovered near the crater of Mount 
 Vesuvius, and in a few rare copper ores. 
 
 Recapitulation of the principal Combinations of Copper. 
 
 of Copper. 
 of Copper. 
 
 Copper ) , , . 5 proto-chloride 
 
 combines with \ chlonne to \per-chloride 
 
 7 i t S proto-sulphuret 
 ml P hurio \bi-sulphurtt 
 
 5. Zinc. 
 
 Chemical Equivalent = 34. 
 
 206. The ore of this metal was formerly imported 
 into Europe from China. In the J6th century it was dis- 
 tinguished as a separate metal, and received its present 
 
BISMUTH. 219 
 
 appellation. It is not found in a native state, but occurs 
 mixed with lead or sulphur. (Most zinc is obtained from 
 an ore called sparry calcimine, which is a carbonate of this 
 metal). Pure zinc has a bluish-white color and a strong 
 metallic lustre. It is less ductile than lead or tin, but when 
 heated to from 212 to 302 Fahrenheit it may be ham- 
 mered, or drawn into wire. Of all metals which are used 
 in common life, it is most expanded by heat. It is capable 
 of volatilization and distillation by heat. 
 
 Combinations af Zinc with Oxygen and Chlorine. 
 
 207. Zinc may be burnt in atmospheric air or chlo- 
 rine. In the first case the combustion is accompanied by 
 a most beautiful blue flame, into which the forming oxide 
 of zinc is thrown up in form of white flakes, formerly 
 known by the name of flowers of zinc. In the second 
 case chloride of tin is formed, which is a soft, grey sub- 
 stance, of the consistency of wax, easily soluble in water, 
 and used (in France) in the process of dyeing. 
 
 Oxide of Zinc 
 
 is composed of 1 equivalent of zinc = 34 
 1 do. of oxygen = 8 
 
 Consequently, chemical equivalent of oxide of zinc = 42. 
 Chloride of Zinc 
 
 is composed of I equivalent of zinc = 34 
 1 do. of chlorine = 36 
 
 Consequently, chemical equiv. of chloride of zinc = 70. 
 Recapitulation of the principal Combinations of Zinc. 
 
 ^ oxygen to oxide } 
 
 Zinc combines with 2 V of Zinc. 
 
 ( chlorine to chloride ) 
 
 6. Bismuth. 
 
 Chemical Equivalent = 71. 
 208. Bismuth is seldom found in its native state ; it 
 
220 COBALT. -ANTIMONY. 
 
 is more frequently combined with oxygen, sulphur and 
 lead. It has a reddish-white color, and a strong metallic 
 lustre. It is very brittle, so that it may be reduced to a 
 powder, is fusible, volatile, and capable of distillation. It 
 is used for the manufactury of pigments and paints. It 
 combines with oxygen and chlorine to oxide and chloride 
 of bismuth, in a manner similar to zinc (see the last sec- 
 tion). Its principal binary combinations may therefore be 
 arranged as follows : 
 
 oxygen to oxide ") 
 
 Rismuth combines with 1 V of Bismuth, 
 
 chlorine to chloride ) 
 
 7, Cobalt. 
 
 Chemical Equivalent not asr.erlained. 
 
 209. The ores of Cobalt were already known in the 
 15th century, and used in the manufactury of blue pig- 
 ments. It is however but a few years since cobalt has been 
 entirely separated from nickel, arsenic and iron, with 
 which it is commonly found combined. The purest cobalt 
 is of a greyish-white color (between silver and steel), and 
 possesses considerable splendor. It is malleable and duc- 
 tile only in an inferior degree (cannot be drawn into wire), 
 is attracted by the magnet, and capable of receiving mag- 
 netic properties (Nat. Phil. Chap. X). The oxides 
 of this metal, which are obtained by exposing it to an in- 
 tense heat in contact with atmospheric air, or by precipit- 
 ating it from a solution in nitric acid, by the addition of 
 potash, occur in commerce mixed with sand or calcined 
 flint, under the name of zaffer and smalts. They are fine 
 blue pigments, and are extensively used for dyeing linen, 
 or to stain glass and China. 
 
 8. Antimony. 
 Chemical Equivalent = 44. 
 
 210. Antimony occurs either native, or in red and 
 grey ore of antimony. It has a dusky white color, consid- 
 
ANTIMONY. 221 
 
 erable metallic lustre and scaly fracture. It is so brittle 
 that it may be reduced to a powder, is fusible and volatile, 
 and burns when heated in the atmosphere. It is used as 
 an alloy in some of the arts, and sometimes it is employed 
 in medicine. Combined with lead it forms the metal of 
 which printers' type is cast. 
 
 Combinations of Antimony with Oxygen, Chlorine and 
 Sulphur. 
 
 211. Antimony combines with oxygen in three dif- 
 ferent proportions. The first of these combinations, 
 
 Protoxide of Antimony, 
 
 is composed of 1 equivalent of antimony = 44 
 1 do. of oxygen =3 8 
 
 Its chemical equivalent, therefore, is = 52. 
 
 It is a product of nature, but may be obtained also by 
 the combustion of antimony in atmospheric air. It is a 
 greyish white powder, which, when taken into the stom- 
 ach, operates like an emetic, melts at a red heat, is vola- 
 tile, and forms, upon cooling, regular crystals. The second, 
 
 Deutoxide of Antimony (Antimonious Acid), 
 
 is composed of 1 equivalent of antimony = 44 
 1J do. of oxygen = 12 
 
 Consequently, chem.equiv. of deutoxide of antimony = 56. 
 
 It is found in some of the ores of antimony, and may be 
 formed by heating the protoxide in the open air. It is a 
 white powder without smell er taste, insoluble in water, 
 and fusible only when submitted to high degrees of heat. 
 It is used in glass and porcelain painting. The third, 
 
 Per-oxide of Antimony, 
 
 is a product of 1 equivalent of antimony = 44 
 and 2 do. of oxygen = 16 
 
 whence its chemical equivalent is = 60. 
 19* 
 
222 ARSENIC. 
 
 It is formed by pouring a solution of antimony in nitro- 
 muriatic acid, see ( 185, page 202) upon water ; the per- 
 oxide is then precipitated. It is of a yellow, straw-color, 
 inodorous and tasteless, and when submitted to a red heat 
 parts with some portion of its oxygen, and is again con- 
 verted into the deutoxide. 
 
 The Proto- chloride or butter of Antimony, is obtained by the 
 combustion of powdered antimony in chlorine. It is soft, and 
 melts at a gentle heat. The per-chloride is produced by 
 bringing heated solid antimony in contact with chlorine. 
 
 Antimony combines yet readily with sulphur. The com- 
 pound is a grey sulphuret, with metallic lustre, and is, among 
 all the ores of antimony, that which is most abounding in nature. 
 
 Recapitulation of the principal Combinations of Antimony. 
 
 C protoxide } 
 
 oxygen to < deutoxide > of Antimony. 
 Antimony 1 ( per-oxide ) 
 
 combines with m . neto \P^^ ^ Antony. 
 
 sulphur to sulphuret of Antimony. 
 
 9. Arsenic. 
 
 Chemical Equivalent = 38. 
 
 212. Arsenic* was first obtained from arsenic acid 
 by Brandt, a celebrated chemist, in 1733. It occurs com- 
 bined with various substances in the mineral kingdom. It 
 is of the color of steel, and has a strong metallic lustre, 
 which, however, is easily tarnished. Its texture is lamellar. 
 At 356 Fahrenheit it forms greyish white vapors, which 
 have a strong smell of garlic. It has a strong affinity 
 for oxygen (powdered arsenic moistened with water may 
 be heated to spontaneous combustion). In oxygen gas it 
 burns with a bluish white flame, leaving arsenic acid. It 
 is poisonous, although less so than the acid. Its use in the 
 arts is very limited. 
 
 * What iii commerce occurs as Jlrsenic, is arsenic acid, or oxide 
 of arsenic. 
 
ARSENIC. 223 
 
 Combinations of Arsenic with Oxygen, Hydrogen and 
 Sulphur. 
 
 213. We know of three different combinations of 
 arsenic with oxygen. The first, 
 
 Oxide of Arsenic, is an indefinite compound, formed by 
 the contact of the metal with atmospheric air, and consists 
 of a dark grey powder. The second, 
 
 Arsenious Acid, 
 
 is composed of 1 equivalent of arsenic =3 38 
 and 2 equivalents of oxygen (each = 8) = 16 
 
 Consequently, chemical equiv. of arsenious acid = 54. 
 
 It is a product of nature. It is white, brittle, and high- 
 ly poisonous. It tastes sweetish, is sparingly soluble in 
 water, but when heated is easily volatilized. It is used in 
 medicine and in some of the arts ; viz : in glass factories, 
 in cotton-printing, and in the preparation of mineral green. 
 It may also be employed to preserve stuffed animals 
 from destructive insects. The third combination of arse- 
 nic with oxygen, 
 
 Arsenic Acid, 
 
 is composed of 1 equivalent of arsenic = 38 
 3 do. of oxygen = 24 
 
 Consequently, chemical equivalent of arsenic acid = 62. 
 
 It occurs in some mineral salts. It may be obtained, 
 also, by the action of nitric acid on heated arsenious acid. 
 It is a white, opaque, inodorous mass, with a pungent, 
 sour taste, and still more poisonous than arsenious acid. 
 
 Arseniuretted Hydrogen. 
 Chemical Equivalent not ascertained. 
 
 214. A combination of arsenic with hydrogen is 
 called arseniuretted hydrogen gas. It is a colorless gas 
 of a nauseous smell. When taken into the lungs it causes 
 giddiness, oppression, and death. 
 
224 MANGANESE. 
 
 Sulphuret of arsenic is a product of nature. It occurs 
 in commerce under the name of Realgar, and is used in 
 dyeing and calico-printing. 
 
 Recapitulation of the principal combinations of Arsenic. 
 
 C oxide of arsenic. 
 \ oxygen to 2 arsenious acid. 
 Arsenic combines with ' f arsenicacid. 
 
 I hydrogen to arseniuretted hydrogen gas. 
 \ sulphur to sulphur et of arsenic. 
 
 10. Manganese. 
 
 Chemical Equivalent = 28. 
 
 215. Manganese occurs as an oxide or sulphuret, 
 sometimes also in combination with chlorine or arsenic. 
 It is of a greyish white color, and has a strong metallic 
 lustre. It is hard, brittle, becomes easily oxydized, and 
 falls to powder. It decomposes water at common temper- 
 atures, and melts when submitted to superior degrees of 
 heat. Little application is made of this metal in the arts. 
 
 Combinations of Manganese with Oxygen and Chlorine. 
 
 216. Manganese combines with oxygen in 4 or 5 
 different proportions. Two of them are indefinite com- 
 pounds, or mixtures of the protoxide, deutoxide, and per- 
 oxide, and neither of them is of much service to the arts. 
 The pcr-oxide is an abundant product of nature, has an 
 earthy appearance (sometimes black, in crystals) and is 
 soluble in water. It is used in the preparation of chlorine 
 for bleaching, and constitutes what is called the glass- 
 makers' soap. From the per-oxide the deutoxide and 
 protoxide may be obtained by heat. By mixing it with 
 nitre, and submitting it to red heat, an acid is obtained, 
 which is called manganesis acid. 
 
 Chloride of manganese is found in some mineral waters 
 and may be obtained by a direct combination of manga- 
 nese with chlorine. It is a red liquid, which is used for 
 the brown ground in calico printing. 
 
TELLURIUM. TITANIUM. CERIUM. 225 
 
 Recapitulation of the principal combinations of Manganese. 
 
 /- C protoxide } 
 
 JVf,_e \ oxygen to ) ^ ^ ^"^ 
 combines with } ( L^imm'c acid. 
 
 {chlorine to chloride of Manganese. 
 
 11. Tellurium* 
 Chemical Equivalent = 29. 
 
 217. Tellurium has but recently been discovered in 
 one of the ores of Transylvania. It occurs seldom, either 
 native or mixed with gold, silver, lead, and bismuth. 
 It possesses a greyish white color, a strong metallic lustre, 
 and a lamellar texture. It is brittle, may easily be redu- 
 ced to a powder, boils when submitted to superior degrees 
 of heat and is capable of distillation. Of all metals it is 
 the worst conductor of electricity. It combines with oxy- 
 gen and hydrogen. No use is made of this metal or its 
 compounds in the arts. 
 
 12. Titanium. 
 Chemical Equivalent not ascertained. 
 
 218. This metal never occurs in its simple form, 
 but is found crystalized in scales of a copper-brown color, 
 in the slags of smelting-furnaces ; a small quantity of ti- 
 tanium being often contained in iron. It is hard and brittle, 
 scratches steel, and is capable of a high polish. It is not 
 fusible at a common red heat, and is under common cir- 
 cumstances, not acted upon by any acid. It combines in 
 two or three proportions with oxygen, which are not easily 
 reduced to the metallic state. 
 
 13. Cerium. 
 
 Chemical Equivalent supposed to be = 50. 
 219. This metal occurs but sparingly in form of an 
 
 * The remaining part of this chapter may be omitted by young 
 pupils until reviewing the book. 
 
226 URANIUM. COLUMBIUM. TUNGSTEN. 
 
 oxide from which it has been obtained in exceeding small 
 quantities by the action of very powerful voltaic batteries. 
 It is a chocolate-colored powder, which a little before red 
 heat ignites and burns vividly, the product of the combus- 
 tion being an oxide of the metal. 
 
 14. Uranium. 
 (Not precisely ascertained). 
 
 220. Uranium is obtained by the action of hydro- 
 gen upon the heated oxide of uranium. It is, like cerium, 
 of rare occurrence, consists of a brown powder, which 
 when polished shows a greyish dark lustre. It combines 
 in two proportions with oxygen. The two products of 
 these combinations, protoxide and per-oxidc of uranium, 
 are employed in porcelain painting, the first gives it a 
 black, and the second an orange color. 
 
 15. Columbium. 
 
 Chemical Equivalent =144. 
 
 221. This metal was discovered by Hatchet, in an 
 American fossil (wherefore its name), it is found very 
 sparingly in form of an acid, from which it is extracted. 
 It is a black powder, which, when polished, becomes of 
 the color and lustre of iron. In thin leaves it is a con- 
 ductor of electricity and is acted upon by boiling nitro- 
 muriatic acid. Its only combination with oxygen is, as 
 we have just said, an acid, from which the metal itself is 
 obtained. 
 
 16. Tungsten ( Wolfram). 
 
 Chemical Equivalent = 96. 
 
 222. Tungsten is obtained from tungstic acid, the 
 only form in which it occurs in some fossils. It is a dark 
 grey powder, which by polishing can be made to assume 
 a weak metallic lustre. It is very infusible. When sub- 
 
CADMIUM. CHROMIUM. 227 
 
 mitted to red heat in contact with atmospheric air, it be- 
 comes oxydized, and, in small portions, is capable of igni- 
 tion. It combines in two proportions with oxygen, forming 
 an oxide and an acid. The latter is a product of nature ; 
 the oxide is obtained by reducing the acid, through the ac- 
 tion of hydrogen gas. 
 
 17. Cadmium. 
 
 Chemical Equivalent = 56. 
 
 223. This metal is contained in the ores of zinc, 
 from which it is obtained chiefly be distillation. It resem- 
 bles zinc in color and properties ; but is more malleable 
 and ductile. It may be drawn into wire or reduced to 
 thin plates. It melts a little before red heat, and burns to 
 a brown oxide, the only compound of cadmium and oxy- 
 gen known. A combination of this metal with sulphur, 
 which is not unfrequently found in a natural state, is of a 
 beautiful yellow color (turning into orange), and has lately 
 been employed in oil-painting.* 
 
 18. Chromium. 
 Chemical Equivalent = 28. 
 
 ^ 224. Chromium is found only in an oxydized state, 
 in the red ore of lead and in combination with iron, from 
 which it is extracted by heat. It is of a greyish-white 
 color, very brittle, but sparingly soluble in boiling nitro- 
 muriatic acid, and combines with oxygen in three propor- 
 tions, forming protoxide of chromium, deutoxide of chro- 
 mium, and chromic acid. 
 
 The protoxide is a product of nature, and may be ob- 
 tained by heating chromium in contact with air. It is a 
 dark green powder, infusible, and insoluble in water ; and 
 is used in porcelain and oil-painting. Deutoxide of Chro- 
 mium is produced by the action of sulphuric acid on chro- 
 
 * An Kalian painter by the name of Demin, employed it lately in a 
 painting (Alfresco), and found it very applicable. 
 
228 MOLYBDENUM. VANADIUM. 
 
 mic acid. It is a dark-brown powder of little lustre, which 
 when heated gives off oxygen. Chromic acid is a product 
 of nature. It is commonly found combined with lead, 
 from which it is obtained by a somewhat difficult process. 
 It is of a red color (when dissolved in water and distilled, 
 it forms beautiful ruby-colored crystals), has a sharp, sour 
 (rather astringent) taste, stains the skin yellow, and is 
 dissolved in contact with the atmosphere, in water or al- 
 cohol. 
 
 1 9. Molybdenum. 
 
 Chemical Equivalent = 48. 
 
 225. Molybdenum occurs only in small quantities, 
 in combination with oxygen, sulphur and lead. It is com- 
 monly obtained by reduction of the heated oxide, through 
 hydrogen gas. It is hard and brittle, and burns when 
 heated in the air, to Molybdic Acid. It combines yet in 
 two other proportions with oxygen forming an oxide and a 
 Molybdous acid. No application is made of this metal or 
 its binary compounds in the arts. 
 
 20. Vanadium. 
 
 Chemical Equivalent not ascertained. 
 
 226. This metal was discovered (by Sesstrom) in 
 1830. It has been found in some of the ores of iron and 
 lead, in Eckersholm in Sweden, and Ximapar in Mexico. 
 The process of procuring it is tedious and difficult. It is 
 obtained in white leaves of a strong metallic lustre. It is 
 so brittle that it cannot be hammered, and does not become 
 oxydized at common temperatures, neither in atmospheric 
 air or in water. It is soluble in muriatic and nitro-muri- 
 atic acid, and combines in three different proportions with 
 oxygen, forming two oxides and one acid. It enters also 
 into combinations with sulphur and chlorine. 
 
REVIEW OF ELEMENTS. 
 
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REVIEW OF ELEMENTS. 
 
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232 RECAPITULATION 
 
 RECA PITULATION. 
 
 Questions for Reviewing the most important Principles 
 contained in the Third Chapter. 
 
 1. QUESTIONS ON THE PRELIMINARY REMARKS ON METALS. 
 
 [ 137.] Is it possible to fix with precision upon the 
 general characteristics of metals? By what properties are 
 they, notwithstanding, more or less distinguishable ? 
 
 Are the metals commonly electro-positive or electro -negative 
 bodies ? Why ? 
 
 [ 138.] To what class of bodies do all metals belong, 
 as far as our experience goes in chemistry 1 What is their 
 number ? What are their names ? 
 
 [ 139.] For what substance have all metals a greater 
 or less affinity ? Under what circumstances do they com- 
 bine with oxygen ? 
 
 What change is wrought upon most metals when they are 
 exposed to air or to moisture ? By what is this change occa- 
 sioned ? To what is the increase of weight proportional ? 
 Which metal, more than all others, attracts oxygen from the 
 air and from moisture ? What is the friable substance called, 
 which collects on the surface of iron ? How are metals pre- 
 vented from rusting ? What was Davy's proposition for pre- 
 venting metals from rusting? Why are steel instruments 
 kept in silver paper ? 
 
 [ 140.] Is oxygen the only substance with which 
 metals combine ? Into what other combinations do the 
 metals yet enter ? What are the products of these respec- 
 tive combinations called ? 
 
 [ 141.] What do you understand by alloys of metals 1 
 What by amalgams ? What properties do the alloys of 
 metals generally possess ? 
 
 [ 142.] What may be done with two metals possessing 
 different degrees of fusibility ? Why is fusion a means of 
 refining ores ? 
 
OF CHAPTER III. 233 
 
 [ 143.] What are metals which easily melt capable 
 of advancing in others ? What process is founded upon 
 this property of the metals ? In what consists the process 
 of soldering ? 
 
 What solder is employed for tin ware ? 
 
 What, for cast iron ? 
 
 What, for copper and brass ? 
 
 How is zinc soldered ? 
 
 How, platinum ? 
 
 How, gold? 
 
 What solder is used for silver ? 
 
 [< 144.] What other process of art is founded upon 
 the natural attraction which exists between some of the 
 metals ? 
 
 Give examples. 
 
 [ 145.] In what state are the metals generally found ? 
 What are they then called 1 Where do they occur ? In 
 what are they generally bedded 1 What are those sub' 
 stances called with which the metals are commonly found 
 combined 1 What substance is most abundantly found 
 combined with the metals 1 What is it therefore called 1 
 What are those metals called which occur in their simple 
 form ? Where is native gold and silver principally found ? 
 
 [ 146.] What is the process called by which the 
 pure metal is extracted from the ore 1 What means are 
 particularly resorted to for this purpose ? 
 
 In what consists the roasting of ores ? 
 
 In what the smelting of ores ? 
 
 In what the refining of metals ? 
 
 [ 147.] What do the similar properties which some 
 metals possess enable us to do 1 
 
 To what class of metals belong potassium, sodium, lithi- 
 nm, calcium, barium, and strontium ? 
 
 What is the name applied to the metals, magnesium^ 
 yttrium, alumium, glucinum, zirconium, and thorium ? 
 
 What are the names of the nine noble metals? 
 
 What metals are most useful to man ? 
 
 20* 
 
234 RECAPITULATION 
 
 A. QUESTIONS ON THE six ALKALINE METALS. 
 
 [ 148.] What is the chemical equivalent of potas- 
 sium ? How may this metal be obtained ? 
 
 How large a galvanic battery is required for the decomposi- 
 tion of hydrate of potash 1 Describe the process by which 
 Thenard and Gay-Lussac decomposed hydrate of potash in a 
 bent gun-barrel. (Explain Fig. CXII). 
 
 [ 149.] What are the characterizing properties of 
 potassium ? 
 
 [ 150.] In how many different proportions does po- 
 tassium combine with oxygen ? Which is the most re- 
 markable of these combinations ? What is its chemical 
 composition ? Where does it occur 1 How may it be ob- 
 tained pure, by art ? 
 
 How is the potash of commerce obtained? What does 
 potash form when united with water ? What substance does 
 this hydrate form in combination with the fat oils? 
 
 [ 151.] What are the properties of the hydrate of 
 potash ? How is it obtained ? 
 
 [ 152.] What is the name given to a solution of hy- 
 drate of potash ? What are its properties? 
 
 [ 153.] To what compound does potassium unite with 
 chlorine ? What is the chemical composition of chloride 
 of potassium ? Where is it found ? How may it be pro- 
 duced by art ? What are its properties 1 
 
 What are the principal binary combinations of Potas- 
 sium ? 
 
 [ 154.] What is the chemical equivalent of sodium ? 
 In what manner is sodium obtained 1 What are its prop- 
 erties 1 For what substance has sodium a strong affinity ? 
 
 [ 155.] What is the chemical composition of soda ? 
 In how many different proportions does sodium combine 
 with oxygen 1 Where does protoxide of sodium, or soda 
 occur ? How is the purest soda obtained ? What are its 
 properties 1 
 
OF CHAPTER III. 235 
 
 [ 156.] What is the chemical composition of chloride 
 of sodium, or common salt? Where does it occur 1 In 
 what is it also largely contained ? By what means may 
 it be procured in its purest state ? In what form does it 
 crystalize ? What does it constitute ? 
 
 WJiatare the principal binary combinations of Sodium ? 
 
 157.] What is the chemical equivalent of lithium ? 
 ow is lithium obtained ? What are its properties ? 
 What is the chemical composition of the oxide of lithium, 
 or lithia 1 
 
 [ 158.] What is the chemical equivalent of calcium? 
 By what means is calcium obtained ? What is the pro- 
 toxide of calcium called ? What is the chemical equiva- 
 lent of lime ? Where does it occur ? How may it be 
 obtained pure ? 
 
 [ 159.] What are the principal properties of lime ? 
 Why is lime said to be a flux 1 What is the taste of lime ? 
 Into what does it become converted by the process of 
 slaking ? 
 
 What are the principal uses of lime ? 
 
 What substance does calcium form in combination with 
 chlorine ? 
 
 What are the two principal binary combinations of 
 Calcium ? 
 
 [ 160.] What is the chemical equivalent of barium ? 
 By what process is barium produced ? What are its prop- 
 erties ? In how many different proportions does it com- 
 bine with oxygen ? What is the protoxide of barium call- 
 ed ? What is its chemical composition ? 
 
 [ 161.] What are the leading properties of baryta? 
 What are the properties of baryta-water ? 
 
 What kind of substance is the per-oxide of barium ? 
 
 With what other substances is barium known to com- 
 bine ? 
 
 What are the principal binary combinations of Barium 1 
 
236 RECAPITULATION 
 
 [ 162.] What is the chemical equivalent of strontium ? 
 How is it procured ? What are its properties 1 In how 
 many proportions does it combine with oxygen ? In what 
 state, and where is the protoxide of strontium, or strontia, 
 generally found ? What is its chemical composition ? 
 What are its properties 1 With what other substances 
 does strontium yet combine ? 
 
 What are the most remarkable binary combinations of 
 Strontium 1 
 
 B. QUESTIONS ON THE six EARTHY METALS, MAGNESIUM, 
 
 YTTRIUM, ALUMIUM, GLUCINUM, ZIRCONIUM, 
 
 AND THORIUM. 
 
 [$ 163.] Is the existence of the six earthy metals 
 proved by actual experiment? Under what names were 
 the oxides of these metals formerly known ? What do the 
 experiments which have been made upon them, together 
 with the strong analogy which exists between them and 
 the alkaline metals prove them to be ? By what partic- 
 ular test are all of them distinguished ? How do they 
 all act upon the acids ? 
 
 [ 164.] What is the chemical equivalent of magne- 
 sium ? By what means may magnesium be obtained ? 
 
 Explain this process by galvanic electricity. Explain the 
 process in which the metal is obtained from the chloride of 
 magnesium. 
 
 What are the properties of magnesium , obtained by either 
 of these processes ? In how many proportions does it 
 combine with oxygen ? What is the compound called ? 
 What is its chemical composition ? 
 
 [ 165.] Where does the oxide of magnesium occur ? 
 From what substance is magnesia obtained for commerce 1 
 By what means is it obtained in its purest state ? 
 
 What are the properties of magnesia ? 
 
 What sort of substance is chloride of magnesium? 
 
 What are the principal binary combinations of Magne- 
 sium ? 
 
OF CHAPTER III. 237 
 
 [ 166.] What is the chemical equivalent of gluci- 
 num ? How is this metal produced 1 
 
 Explain the process. 
 
 By what sort of reasoning are we led to the inference that 
 the dark colored globules which in your experiment ap- 
 pear disseminated throughout the whole mass, are actually the 
 metal glucinum ? What strong analogy does glucina bear to 
 those substances which we know to be oxides of metals? 
 
 What are the properties of glucinum ? 
 
 Where does the oxide of glucinum, or glucina occur ? 
 What sort of substance is it 1 What is its chemical 
 equivalent supposed to be ? 
 
 167.] What is the chemical equivalent of yttrium? 
 ow is this substance obtained 1 
 What are its properties ? 
 
 Where is the oxide of yttrium found ? What is it call- 
 ed ? By what peculiarity are all the salts of yttria dis- 
 tinguished ? 
 
 [ 168. ] What is the chemical equivalent of alumium ? 
 What are its properties 1 
 
 What is the chemical composition of alumia? 
 
 [ 169.] Where does alumia occur? In what sub- 
 stances is it contained in its simple form ? What are its 
 properties ? For what purposes is it used ? With what 
 substances does alumium yet combine ? 
 
 What are the principal binary combinations of Alum- 
 ium ? 
 
 [ 170.] By what means has zirconium been obtained 
 in its simple form ? What are its properties ? 
 
 Where has the oxide of zirconium, or zirconia been 
 found ? What are its properties ? 
 
 [ 171.] By what means was thorium produced? 
 What are its properties ? Where is the oxide of thorium 
 found ? 
 
238 RECAPITULATION 
 
 C. QUESTIONS ON THE NINE NOBLE METALS, MERCURY, 
 SILVER, GOLD, PLATINUM, PALLADIUM, RHODIUM, 
 IRIDIUM, OSMIUM, AND NICKEL. 
 
 [ 172.] What is the chemical equivalent of mercury ? 
 Where does mercury occur ? 
 
 How is mercury obtained from the ore ? 
 
 [ 173.] What are the characterizing properties of 
 mercury ? 
 
 [ 174.] What peculiar power does mercury possess ? 
 
 How is this property of mercury taken advantage of? What 
 other application is made of the amalgams of gold ? What ap- 
 plication is made of the amalgam of silver ? For what partic- 
 ular purpose is the amalgam of tin used ? 
 
 [ 175.] In how many different proportions does mer- 
 cury combine with oxygen 1 What is the chemical 
 composition of protoxide of mercury ? By what means 
 is it obtained 1 What is the composition of per-oxide of 
 mercury ? 
 
 [ 176.] How is per-oxide of mercury obtained ? 
 
 [^ 177.] In how many proportions does mercury com- 
 bine with Chlorine ? What is the composition of proto- 
 chloride of mercury ? By what name is this compound 
 generally known ? 
 
 [ 178.] How is calomel obtained ? 
 
 [ 179.] How is per-chloride of mercury formed ? 
 How is corrosive sublimate prepared for medicinal pur- 
 poses ? 
 
 [ 180.] What are the properties of corrosive subli- 
 mate ? 
 
 [ 181.] In how many different proportions does mer- 
 cury unite with sulphur ? What is the chemical com- 
 position of proto-sulphuret of mercury 1 How is it ob- 
 tained ? 
 
OF CHAPTER III. 239 
 
 [ 182.] What is the chemical composition of bi-sul- 
 phuret of mercury? By what other name is this com- 
 pound known 1 Is it a product of nature 1 How may it 
 be produced by art? For what purposes is it employed ? 
 
 What are the principal binary combinations of Mercury ? 
 
 [ 183.] What is the chemical equivalent of silver ? 
 and in what state found ? Where is this metal principal- 
 ly found? What are its properties? With what sub- 
 stance is silver generally alloyed ? What other metal 
 does it often contain in minute quantities? For what 
 purposes is it used ? 
 
 [ 184.] With what substances does silver combine? 
 What are the names of the products thus formed ? 
 
 What is the chemical composition of oxide of silver ? 
 
 How is it obtained ? 
 
 What is the chemical composition of chloride of silver ? 
 By what other name is this substance known ? How 
 is it formed ? What are its properties ? 
 
 For what purposes is a mixture of silver, chalk, and pearl- 
 ash used ? 
 
 What is the composition of sulphuret of silver ? Where 
 does this compound occur ? What are its properties ? For 
 what is it used ? 
 
 WJiat are the principal binary combinations of Silver 1 
 
 185.] What is the chemical equivalent of gold ? 
 n what state is gold found? Where does it principally 
 occur ? 
 
 What are its properties ? By what mixture of acids is 
 gold operated upon ? What, therefore, has this mixture 
 been called ? 
 
 By what means may gold be revived from a solution in ni- 
 tro muriatic acid ? What beautiful experiment may on this 
 account be made with it? For what purpose is the etherial 
 solution of gold used ? How is it prepared ? 
 
 [ 186.] In how many different proportions does gold 
 combine with oxygen ? With what other substances does 
 it yet combine ? 
 
240 RECAPITULATION 
 
 What are the principal binary combinations of Gold ? 
 
 [ 187.] What is the chemical equivalent of platinum ? 
 Who first analyzed the ores of platinum ? What other 
 substances (besides platinum) does the ore of platinum 
 generally contain 1 For what purposes is platinum used 
 in Russia? What are the properties of platinum? With 
 what substances does platinum unite ? 
 
 For what two purposes is platinum used in chemistry ? In 
 what cases is it well adapted to the manufacture of crucibles ? 
 How is the flameless or aphlogistic lamp constructed ? (Ex- 
 plain Fig. CXIII). How is this phenomenon explained ? 
 
 How is platinum-sponge prepared ? How does hydrogen 
 gas act upon platinum-sponge ? Explain Prof. Dobereiner's 
 apparatus for producing instantaneous light. (Explain Fig. 
 CXIV). 
 
 [ 188.] What is the chemical equivalent of palladi- 
 um ? Where does it occur ? With what other substance 
 is it found combined in Brazil 1 What are its properties 1 
 By what acids is it operated upon 1 What are the prop- 
 erties of sulphuret of palladium ? 
 
 [ 189.] What are the properties of rhodium ? 
 How is the oxide of rhodium obtained ? What are its 
 properties 1 
 
 [ 190.] What is the chemical equivalent of iridium ? 
 Where is it found 1 What are its properties ? 
 
 [ 191.] What is the chemical equivalent of osmium? 
 How is this metal obtained ? What are its properties ? 
 
 [ 192.] What is the equivalent number of nickel ? 
 
 With what substances is nickel generally united ? By 
 what name is the latter of these combinations known in 
 commerce ? What are the properties of nickel ? How is 
 it acted upon by the magnet ? Into what does it become 
 converted when heated ? 
 
OP CHAPTER III. 241 
 
 D. QUESTIONS ON THE REMAINING METALS, IRON, TIN, 
 
 LEAD, COPPER, ZINC, BISMUTH, COBALT, ANTIMONY, 
 
 ARSENIC, MANGANESE, TELLURIUM, TITANIUM, 
 
 CERIUM, URANIUM, COLUMBIUM, TUNGSTEN, 
 
 CADMIUM, CHROMIUM, MOLYBDENUM, 
 
 AND VANADIUM. 
 
 [ 193.] What is the chemical equivalent of iron ? 
 In what state is iron generally found ? What are its 
 properties. 
 
 What sort of ore is the native magnet ? In what state does 
 it occur ? What are its chemical properties ? 
 
 [^ 194.] In how many proportions does iron combine 
 with oxygen ? What is the chemical equivalent of pro- 
 toxide of iron 1 
 
 What, that of the per-oxide of iron ? 
 
 How is the per-oxide of iron obtained ? What are its 
 properties 1 How is the protoxide obtained ? What are 
 its properties ? How is the black oxide of iron formed ? 
 What sort of compound is it 1 
 
 [$} 195.] In how many proportions does iron combine 
 with chlorine 1 What are the names of the compounds 1 
 What, their composition 1 How is proto-chloride of iron 
 produced ? What are its properties ? How is per-chlo- 
 ride of iron obtained ? What are its properties ? 
 
 [ 196.] What sort of product are the sulphurets of 
 iron ? By what name is the bi-sulphuret known ? Of 
 what color is it ; and in what state is it found ? How may 
 the proto-sulphuret of iron be produced ? 
 
 What is the chemical composition of proto-sulphuret of 
 iron 1 What, that of the bi-sulphuret? 
 
 [ 197.] In what manner is steel formed? What 
 peculiar properties does it possess in a higher degree thati 
 iron? What process must steel undergo in order to be- 
 come adapted to the different uses for which it is destined ? 
 In what does the process of tempering consist? 
 
 21 
 
242 RECAPITULATION 
 
 What are the principal binary combinations of iron 1 
 
 [ 198.] What is the chemical equivalent of lead ? 
 What are the principal properties of lead ? For what 
 purposes is it extensively used ? 
 
 [ 199.] In how many different proportions does lead 
 combine with oxygen ? What are the names of the pro- 
 ducts ? What is the chemical composition of the sub-ox- 
 ide of lead ? What, that of the protoxide ? What, that of 
 the deutoxide ? What, that of the per-oxide ? 
 
 By what means may all these oxides be obtained ? What 
 peculiar property do they possess? For what purpose, 
 therefore, are they used ? 
 
 Explain the process of cupellation. 
 
 How is the protoxide of lead (or massicot of commerce) ob- 
 tained ? What is this substance called when partially melted ? 
 
 By what name is the deutoxide of lead known in commerce ? 
 What are its properties ? 
 
 How is chloride of lead produced ? What are its prop- 
 erties? What is its chemical composition ? 
 
 What sort of product is the sulphuret of lead ? What kind 
 of ore does it constitute ? 
 
 What are the principal binary combinations of Lead 1 
 
 [ 200.] What is the chemical equivalent of tin ? To 
 whom was this metal already known 1 In what state does 
 it commonly occur ? What are its properties in a pure 
 state ? 
 
 [ 201.] In how many different proportions does tin 
 combine with oxygen 1 W T hat is the chemical composition 
 of the protoxide of tin 1 What that of the per-oxide ? 
 How may both products be obtained ? 
 
 What becomes of tin, when fused, and in this state for a 
 long time exposed to the atmosphere ? What becomes of the 
 protoxide when again exposed to heat in contact with air? 
 
 What are the properties of the per-oxide of tin ? For 
 what purposes are the oxides of tin used ? 
 
 How are proto-chloride and per-chloride of tin obtained ? 
 What are the properties of the proto-chloride ? What, those 
 of the per-chloride ? 
 
or CHAPTER in. 243 
 
 What is the chemical composition of proto-chloride of tin ? 
 What is the chemical composition of the per-chloride? 
 
 [ 202.] How are the two sulphurets of tin produced ? 
 What are their properties? 
 
 What are the principal binary combinations of Tin ? 
 
 [ 203.] What is the chemical equivalent of copper ? 
 How long is it since this metal has been wrought ? In 
 what state is it found ? With what substances is it common- 
 ly connected ? What are its properties ? For what pur- 
 poses is it used ? In what consists one of its chief appli- 
 cations ? 
 
 [ 204.] In how many proportions does copper com- 
 bine with oxygen ? Of what color is the protoxide ? Of 
 what the deutoxide ? What is the chemical composition of 
 these substances ? 
 
 [ 205.] How is proto-chloride and per-chloride of 
 copper obtained ? What are the properties of the proto- 
 chloride ? What those of the per-chloride ? What prop- 
 erty does per-chloride of copper communicate to spirits of 
 wine in which it is dissolved ? 
 
 What is the chemical composition of proto-chloride of 
 copper ? What is the chemical composition of the per- 
 chloride ? 
 
 What products are the sulphurets of copper ? Where 
 does the proto-sulphuret of copper occur ? 
 
 What are the most important binary combinations of 
 Copper ? 
 
 [ 206.] What is the chemical equivalent of zinc ? 
 In what state is zinc found ? What are its properties ? 
 How is zinc acted upon by heat ? 
 
 [ 207.] How are the oxides and chlorides of zinc 
 formed ? 
 
 What are the properties of the oxide of zinc? Wiiat 
 those of chloride ? What is the chemical equivalent of 
 oxide of zinc ? What that of the chloride ? 
 
 [ 208.] What is the chemical equivalent of bismuth? 
 
244 RECAPITULATION 
 
 Where does this metal occur ? What are its properties ? 
 For what purposes is it used ? What are its principal 
 binary combinations? 
 
 [ 209.] With what substances is cobalt generally 
 found combined ? What are the properties of pure cobalt 1 
 How are the oxides of this metal obtained ? Under what 
 name do they occur in commerce ? For what purposes are 
 they used ? 
 
 [ 210.] What is the chemical equivalent of antimony ? 
 Where does it occur 1 What are its properties ? For 
 what purposes is it used 1 
 
 [ 211.] In how many different proportions does 
 antimony combine with oxygen ? What is the chemical 
 composition of the protoxide ? How may it be obtained ? 
 What are its properties^ 
 
 How may the deutoxide be obtained? What are its 
 properties? What is the chemical composition ofper-ox- 
 ide of antimony ? By what means is it formed ? What 
 are its properties 7 
 
 How is the Proto-chloride or butter of antimony obtained ? 
 What are its properties ? With what other substances does 
 cobalt yet combine ? 
 
 What are the principal binary combinations of Anti- 
 mony 1 
 
 [<, 212.] What is the chemical equivalent of arsenic ? 
 By whom was arsenic first obtained ? Where does it oc- 
 cur ? What are its properties ? 
 
 [ 213.] In how many proportions does arsenic com- 
 bine with oxygen 1 What sort of compound is oxide of 
 arsenic ? What are its properties ? What is the chem- 
 ical composition of arsenious acid ? What are its proper- 
 ties ? For what purposes may it be used ? 
 
 What is the composition of arsenic acid ? 
 
 Where does it occur ? How may it be obtained by art ? 
 
 [ 214.] What is a combination of arsenic with hy- 
 drogen called ? What are its properties ? 
 
OF CHAPTER III. 245 
 
 Under what name does the sulphuret of arsenic occur 
 in commerce 1 For what is it used ? 
 
 What are the principal binary combinations of Arsenic 1 
 
 [ 215.] What is the chemical equivalent of manga- 
 nese ? Where does manganese occur ? What are its 
 properties ? 
 
 [ 216.] In how many proportions does manganese 
 combine with oxygen ? For what purposes is the per-oxide 
 used ? Where does the chloride of manganese occur ? 
 
 What are the principal combinations of manganese ? 
 
 [ 217.] What is the chemical equivalent of telluri- 
 um ? Where does this metal occur ? What peculiar 
 property has it, among the metals ? 
 
 [ 218.] In what state does titanium occur? What 
 are its properties ? 
 
 [ 219.] What is the chemical equivalent of cerium ? 
 Where does it occur 1 What are its properties ? 
 
 [ 220.] How is Uranium obtHned ? What are its 
 properties 1 In how many proportions does it combine 
 with oxygen ? 
 
 [ 221.] What is the chemical equivalent of columbi- 
 um 1 By whom was it discovered ? In what ? What 
 are its properties 1 In how many proportions does it com- 
 bine with oxygen ? 
 
 [ 222.] What is the chemical equivalent of tungsten ? 
 Where does it occur ? What are its properties ? In how 
 many different proportions does it combine with oxygen ? 
 
 [ 223.] What is the equivalent number of cadmium ? 
 By what means is this metal obtained? What metal does 
 it resemble in color and properties ? What are its other 
 properties ? What combination of this metal has lately 
 been employed in oil-painting ? 
 
 [ 224.] What is the chemical equivalent of chromium ? 
 21* 
 
246 RECAPITULATION. 
 
 In what state is this metal found ? What are its proper- 
 ties 1 In how many different proportions does it combine 
 with oxygen 1 How may the protoxide be obtained ? 
 What are its properties ? How is the deutoxide produced ? 
 What are its properties ? What sort of product is chro- 
 mic acid 1 What are its properties? 
 
 [ 225.] Where does molybdenum occur 1 How is 
 it obtained ? What are its properties ? 
 
 [ 226.] By whom was vanadium first discovered 1 
 Where has it been found ? What are its properties ? In 
 how many proportions does it combine with oxygen ? 
 
OF THE SALTS. 247 
 
 CHAPTER I V. 
 
 OF THE Q,UARTERNARY COMBINATIONS OF BODIES, OR 
 
 SALTS, 
 
 General Remarks on the Acids. 
 
 227. The general characteristics of those binary 
 compounds (combination of one element with another) 
 called acids, have already been enumerated in the intro- 
 duction, page 38. It will be well now to draw a few gen- 
 eral inferences from the properties of these substances, as 
 far as we have become acquainted with them in the three 
 preceding chapters. 
 
 Among the different elements, oxygen and hydrogen 
 are by far the most powerful agents in nature. They 
 enter into almost every composition of organic or inor- 
 ganized matter ; and although marked by the most dis- 
 tinguishing properties which can possibly designate two 
 heterogeneous bodies, the product of their union water 
 is the most indifferent (neutral) substance known ; and so 
 perfect and compact is this compound, that it occupies 
 less than one two thousandth part of the volume which its 
 two constituent gases (hydrogen and oxygen) occupy be- 
 fore their combination (Chap. I, 27). But although oxy- 
 gen and hydrogen are capable of thus neutralizing each 
 oilier, their relation to other substances is quite different. 
 For it may be said that all bodies, in relation to these two 
 are merely passive, and receive as it were their character- 
 izing properties from the proportion in which they combine 
 with either oxygen or hydrogen. 
 
248 GENERAL REMARKS 
 
 As an instance we may take the different properties of the 
 combinations of nitrogen with oxygen (see Chap. I, 46,) 
 which seem solely to depend on the proportion in which the 
 latter substance combines with the former. And so entirely 
 are the original characteristics of nitrogen changed by its 
 union with oxygen, that 4 volumes of it, mixed with 1 volume 
 of oxygen, form a respirable gas, eminently calculated to sup- 
 port animal life, while a combination of one volume of nitro- 
 gen with five volumes of oxygen, constitutes a body in the 
 highest degree destructive to all organic formation. 
 
 228. The most remarkable products obtained by the 
 combination of oxygen and hydrogen with other substan- 
 ces, are the acids. The body which in combination with 
 oxygen or hydrogen forms an acid, is called the radical, 
 and the oxygen or hydrogen with which it unites is termed 
 the acidifying principle. Thus, in nitric acid (see 56), 
 oxygen is the acidifying principle ; but in muriatic acid 
 and prussic acid it is hydrogen. 
 
 It is here important to observe that every acid may be con- 
 sidered as the union of an electro-positive with an electro nega- 
 tive body* ; the radical being always the electro-positive, and 
 the acidifying principle the electro-negative factor. 
 
 It was formerly believed that oxygen was the acidifying 
 ingredient of every acid, but the discovery of the acidifying 
 qualities of hydrogen has sufficiently corrected that error. 
 (Compare the note at the bottom of this page). 
 
 * The ancient divisions of bodies into acidifying substances or sup- 
 porters of combustion, and such as are capable of being acidified or 
 burnt (combustibles), is vague and no longer applicable. For it 
 has been proved tbat one and the same substance may in one instance 
 be capable of combustion with oxygen, and in another be the acid- 
 ifying principle in combination with a different substance. 
 
 To give an example : Hydrogen combines with oxygen to com- 
 bustion, the product being water (see Chap. I, 23), while on the 
 other hand it communicates the acid qualities to muriatic, iodic, and 
 fluoric acid ( 67, 124, 133). Thus, hydrogen would belong 
 to both the combustible and the acidifying substances. There are, 
 moreover, but few substances, besides oxygen, capable of supporting 
 combustion (only a small number of bodies burn in chlorine, iodine, 
 and fluorine). All ordinary processes of combustion result from a 
 combination of oxygen with a combustible basis; and most acids are 
 supporters of combustion only by virtue of the greater or less quantity 
 of oxygen which enters into their composition. 
 
ON THE SALTS. 249 
 
 J 229. Those acids in which hydrogen enters as the 
 acidifying principle, are called hydro adds. To these 
 belong 
 
 The Muriatic add, composed of chlorine and hydrogen 
 (see Chap. I, 67). 
 
 The Hydro-bromic add, composed of bromine and hy- 
 drogen (see Chap. II, 129). 
 
 The Hidriutic add, composed of iodine and hydrogen 
 (see Chap. II, 125). 
 
 The Hydro-fluoric add, composed of fluorine and hy- 
 drogen (see Chap. II, 134). 
 
 The Sulphureted hydrogen, composed of sulphur and 
 hydrogen (see Chap. II, 106). 
 
 The Hydro-cyanic, or prussic acid, composed of cyano- 
 gen and hydrogen (see Chap. II, 90). 
 
 Many other acids, however, require water (consequent- 
 ly also hydrogen, which is an ingredient of water) for their 
 solid or liquid form. These acids are termed hydrates, 
 and have likewise the word ' hydro' prefixed to their 
 names. Thus, we speak of hydro-nitric acid, hydro-sul- 
 phuric acid, &/c. Those acids in which water does not 
 enter as an essential ingredient are called an-hydrous, 
 (Compare the remark 58, page 99). 
 
 230. The acids combined with those substances 
 called bases (see Intro, page 38) form a new class of bodies 
 designated by the name of salts. A salt, therefore, is 
 a combination of a basis with an acid. 
 
 When a salt is again decomposed by the almost univer- 
 sal agency of galvanic electricity, the acid adheres inva- 
 riably to the positive pole, while the basis is attracted by 
 the negative pole of the battery. Hence from the law of 
 electricity we may infer that the acids are electro -negative, 
 and the bases electro-positive substances. 
 
 This is a remark we have already had occasion to make in 
 the Introduction, pages 38 and 39, where we have stated that 
 galvanic electricity is by far the best criterion of an acid or a 
 basis. Neither the sour taste nor the changing of vegetable 
 colors can be relied upon as infallible characteristics. 
 
 We have already stated in the Introduction that some chem- 
 ists of distinction, at the suggestion of Sir Humphrey Davy, are 
 
250 GENERAL, REMARKS 
 
 inclined to believe that all chemical phenomena are the result 
 of electrical attractions, either in the same or in opposite di- 
 rections. This theory has lately been supported by some of 
 the most distinguished English chemists, and is indeed so 
 strongly corroborated by facts that it must at least be consid- 
 ered an ingenious hypothesis, which in course of time may 
 perhaps arrive at greater perfection. We will now only men- 
 tion a few facts attending the decomposition of salts by galvanic 
 electricity, which are in themselves highly interesting, and 
 may serve to explain why the bases are called electro-posi- 
 tive, and the acids electro-negative bodies. 
 
 Fig. CXV. 
 
 EXPERIMENT I. When a solution of a salt is made in water, 
 and placed in two cups, a and 6, of which one is connected 
 with the positive or zinc pole, and the other with the negative 
 or copper pole of a galvanic battery, and a communication is 
 established between the two cups by a wet conductor (which 
 may be a piece of cotton or some other moistened substance) ; 
 then after the battery has been for some time in motion, the 
 acid of which the salt is composed will pass into the cup con- 
 nected with the positive or zinc pole and the basis will be trans- 
 ferred to the cup which is connected with the negative, or cop- 
 per pole so that after sometime the solution in the cup 
 a, will have acquired a sour taste, and that in the cup 6, 
 will taste alkaline. 
 
 Now this phenomenon is easily accounted for by the electric 
 attraction of the battery. The salt which, as we have said, is 
 always a compound of an acid with a basis, is by the opposite 
 electric attraction of the battery decomposed into its two con- 
 stituent principles ; because the positive pole of the battery at- 
 tracts the acid, and the negative pole the basis, more strongly 
 than these substances attract each other; their combinatory at- 
 traction therefore is overcome or destroyed, which enables each 
 of them to follow the impulse received by the attractive force of 
 electricity, and it is on this account, the acid, which is the elec- 
 
ON THE SALTS. 251 
 
 tro-negative substance, collects (by the law of opposite at- 
 traction, Natural Philosophy, Chap. X) in the cup near the 
 negative pole, and the alkali, or basis, passes over into the cup 
 connected with the positive pole, because it is an electro-neg- 
 ative body. 
 
 A still more striking instance, showing the decomposing 
 power of galvanic electricity, is the following 
 
 EXPERIMENT II. Place a saline solution in the middle cup d, 
 
 Fig. CXVI. 
 
 and pure water in the two cups c and e. Connect the water in 
 the cups c and e, respectively with the positive and negative 
 poles of the battery, and establish a direct communication be- 
 tween the three cups c, rf, e, as in the last experiment, by means 
 of some wet conductor. After the battery has for some time 
 been in motion, the saline solution contained in the cup d, will 
 not only be decomposed, but will absolutely have disappeared 
 from this cup the acid being transferred to the cup c, con- 
 nected with the positive pole, and the alkaline basis to the cup 
 e, connected with the negative pole of the battery, while the 
 liquid in the cup d, will have acquired a pure taste, like water. 
 
 We see from this expperimcnt that the attractive force of 
 galvanic electricity has not only the power of decomposing a 
 saline solution, but is actually capable of acting through the 
 medium of another substance. But what is still more sur- 
 prising, it is even capable of suspending the laws of affinity 
 which one body has for another, as is proved by the following 
 fact. 
 
 If in the last experiment a solution of sulphate of soda 
 is put in the cup connected with the negative or copper 
 pole, and in the other two an infuson of red cabbage, (which is 
 a strong test of the presence of an acid, because most acids 
 
252 GENERAL REMARKS 
 
 change its color), then after the galvanic battery has been for 
 some time in motion, the sulphate of soda becomes decom- 
 posed, and the sulphuric acid of which it is composed is trans- 
 ferred to the cup which is connected with the positive pole of 
 the battery, without changing in the least degree the color of 
 the infusion in the middle cup, through which it is obliged to 
 pass. If the middle cup is filled with an alkaline solution, the 
 acid is still transferred to the positive pole of the battery, with- 
 out combining in the least with it, and in the same manner 
 may an alkaline solution be transferred through an acid. 
 
 Now these experiments, if they are not sufficient to prove 
 beyond a doubt the correctness of the electro-chemical theory, 
 given in the introduction, justify at least what we have said 
 in reference to the criterion of an acid and a basis and the 
 classification of bodies into electro-positive and electro-negative 
 substances. 
 
 231. The bases, or, as they are sometimes called, the 
 salijiable bases, with which the acids combine, are, with the 
 exception of ammonia (Chap. I, 61), all OXIDES, or at 
 least combinations of oxygen. Both inorganic arid organ- 
 ic bodies are capable of being salifiable bases, that is, or 
 to combine with the acids to salts. 
 
 They are therefore divided into 
 
 I. BASES FROM THE MINERAL KINGDOM. 
 
 A. SOLUBLE IN WATER. B. INSOLUBLE IN WATER. 
 
 a. Easily soluble, b. Not easily a. Earths, b. The remaining 
 
 Soluble. METALLIC 
 
 Potash, Baryta, Alumine, bases. 
 
 Soda, Strontia, Berillia, 
 
 Lythia, Lime, Yttria, 
 
 Ammonia, Magnesia, Zirconia, 
 
 Thoria. 
 
 II. ORGANIC BASES. 
 
 A. VEGETABLE BASES. B. ANIMAL BASES. 
 
 The different properties of these bases, with the exception 
 of those from the animal arid vegetable kingdoms (which will 
 
ON THE SALTS. 253 
 
 be treated of in animal and vegetable chemistry, (see Chapters 
 V, and VI), have already been described in the preceding 
 sections. 
 
 REMARK. Since all the bases here enumerated are al- 
 ready binary combinations of an element with oxygen, and 
 the acids with which they combine are likewise composed 
 of two principles, it follows that we may consider a salt as 
 a combination of two binary compounds or, which is 
 the same, as a Quarternary compound. 
 
 Nomenclature of Salts. 
 
 232. Each of the acids we have become acquainted 
 with in the preceding chapter, is capable of uniting with 
 all the bases just enumerated ; each, therefore, forms a 
 distinct class of salts, which is generally denominated after 
 the acid which enters into its composition. The way in 
 which this is done is easily understood : The termination 
 of the acid ending in ic is changed into ate ; that which 
 ends in ous into ite ; to which is added the name of the 
 base, in the genitive case. Thus, the salts which are form- 
 ed by the combination of sulphun'c acid with the different 
 salifiable bases, are called sulphates ; those in which sul- 
 phuroMs acid is an ingredient are called sulphas ; and so 
 of the rest. Now if, for example, we wished to denote the 
 salt arising from the combination of sulphune acid with 
 soda, we should call it sulphate of soda; if we wished to 
 denote the salt in which sulphurous acid is united with 
 ammonia, we say sulphzfe of ammonia, &c. 
 
 This nomenclature of the salts is of immense advantage to 
 the memory, and infinitely preferable to the arbitrary names 
 by which they were formerly designated. Thus, instead of 
 Glauber's salts, butter of antimony, &.c, we say now sulphate of 
 soda, muriate of antimony, &c, by which appellations we can- 
 not but recollect their constituent principles, viz. : sulphuric 
 acid and soda, muriatic acid and antimony, &c. 
 
 It will therefore be unnecessary to describe the elementary 
 ingredients of the salts, as their appellations sufficiently indi- 
 cate their composition. 
 
 Neutral, sour, and basic Salts. 
 
 233. The salts have yet been divided into neutral, 
 sour, and basic salts. By a neutral salt is meant one in 
 22 
 
254 CRYSTAL OGKAPHY'. 
 
 which the properties of the acid and the base of which it 
 consists are neutralized ; sour are those salts in which the 
 acid properties are prevalent ; and basic those in which the 
 properties of the basis are yet distinguishable. 
 
 Decrepitation of salts. 
 
 234. All salts which are obtained from crystals, con- 
 tain a certain proportion of water either mechanically en- 
 tangled in which case it is called water of cry stalization 
 or chemically combined as an essential principle to 
 their formation. Those which contain water mechanically 
 entangled, easily decrepitate, that is, fly off in small par- 
 ticles when thrown into fire. This is owing to the expan- 
 sion of steam, into which their water of crystalization is 
 converted by exposure to heat. Those salts in which wa- 
 ter is a chemical constituent hardly ever decrepitate. 
 
 Phenomena of efflorescence and deliquescence. 
 
 235. Some salts lose their water either at common 
 temperatures of the atmosphere, in which case they become 
 a shapeless powder, and are said to effloresce, or they absorb 
 moisture from the atmosphere, and melt, which process is 
 called that of deliquescence. But there are others which may 
 be melted in a strong heat, without being decomposed ; and 
 there are salts which melt in their own water, when its solv- 
 ing power is increased by heat. The first process is called 
 igneous fusion ; the second is termed aqueous fusion. 
 
 Crystalography . 
 
 Before entering on the description of the chemical proper- 
 ties of salts, we must here mention some highly interesting 
 peculiarities in their chemical conformations which were first 
 noticed by Haiiy, a celebrated French philosopher, and have 
 since occupied much of the time and researches of many dis- 
 tinguished chemists. 
 
 We have already stated (in the first chapter of Nat. Phil.) 
 that whenever a body passes from the liquid to the solid state, 
 or, in other words, whenever a body from a state of solution is 
 converted into a solid, so that its particles are capable of fol- 
 lowing their own mutual attractions, they arrange themselves 
 in' regular mathematical forms, in which state they are called 
 crystals. These crystals are of various shapes, according to 
 
CRYSTALOGRAPHY. 
 
 255 
 
 the different substances of which they are formed, and it even 
 happens that the crystals of one and the same substance are 
 capable of assuming different geometrical forms. Now it 
 was reserved for Haiiy first to show by a series of the most 
 beautiful experiments, that all crystals are more easily divided 
 in certain directions than in others, so that if a portion be cut 
 off in one of these directions, the surface will be perfectly 
 smooth and regular, whereas, in every other direction we ob- 
 tain a rough surface or a common fracture. By continuing the 
 division of a crystal, following always the direction in which 
 it is most readily divided, and presents a regular, smooth sur- 
 face, Haiiy finally arrived at certain geometrical forms, which 
 were then no longer divisible without fracture. This geomet- 
 rical form, which is, as it were, the nucleus of the crystal, he 
 called the primitive form of the crystal, and the shape which it 
 had before the division he called the secondary form. 
 
 By a long and painful investigation of a great variety of 
 crystals he found that their primitive forms were all reducible 
 to six regular, geometrical solids, which are, 
 
 1st. The parallelepiped, which form includes the cube 
 
 Fig. CXVII. Fig. CXVIII. Fig. CXIX. 
 
 (Fig. CXVII), the four-sided prism (Fig. CXVIII), and the 
 rhomboid three solids which are bounded by six quadrilateral 
 faces. 
 
 2d. The tedrahedron, of which three different views are given 
 Fig. CXX. 
 
 in Fig. CXX, and which is bounded by four triangular surfaces 
 
256 
 
 CRYSTALOGRAPHY. 
 
 3d. The octahedron, of which two differest views (in outline, 
 and shaded) are given in Fig. CXXI, bounded by eight trian- 
 gular sides, or which may also be conceived as formed by join- 
 ing the bases of two triangular pyramids. 
 
 Fig. CXXI. Fig. CXXII. 
 
 4th. The six-sided prism, represented in Fig. CXII, bound- 
 ed by six parallelograms, and two parallel bases. 
 
 5th. The rhombic dodecahedron, represented in Fig. CXXIII, 
 bounded by twelve rhomboidical surfaces, and 
 
 Fig. CXXIII. Fig. CXXIV. 
 
 r 
 
 6th. The dodecahedron, represented in Fig. CXXIV, which 
 is a solid, bounded by twelve triangles, and which may be 
 conceived to be formed by the junction of the bases of two six- 
 sided pyramids. 
 
 These six forms being not so simple as we might expect from 
 a pure mathematical investigation of their formation, it is high- 
 ly probable that the more complicated of them are themselves 
 composed of the more simple ones, which, according to the 
 Fig. CXXV. Fig. CXXVI. Fig. CXXVII. 
 
CRYSTALOGRAPHY. 
 
 257 
 
 opinion of some philosophers, are the tedahedron (Fig. CXXV), 
 the triangular prism (Fig. CXXVI),and the parallelepiped (Fig. 
 CXVll), because it may be proved mathematically that the six 
 primitive forms may be produced by a proper combination of 
 these three. On this account the three solids which we have just 
 named, are called integrant molecules, because they are con- 
 ceived to be the constituent geometrical forms from which the 
 secondary shape and even the primitive forms of all crystals 
 are derived. 
 
 As an example we will only mention the six-sided prism, 
 or in fact any prism whatever, which may evidently be divided 
 into as many triangular prisms as it has sides, by drawing from 
 all the corners straight lines to the centre of the bases and 
 passing planes in the direction of these lines ; and the rhombic 
 dodecahedron, which it is easily perceived may be formed by 
 
 Fig. CXXVIII. 
 
 integrant cubes, as rep- 
 resented in the figure, 
 by placing rows of them 
 upon all the sides of the 
 cubical nucleus, making 
 each row recede one 
 step further, until reg- 
 ular pyramids are form- 
 ed, of which two and 
 two form a rhombical 
 surface. (This is shown 
 in the figure, which is 
 taken from Hauy's Phi- 
 losophy, plate II, fig. 
 12.) Three sides of the 
 cubic nucleus are pur- 
 posely left remaining to 
 exhibit the gradual for- 
 mation of a rhombic surface upon two contiguous sides. 
 
 This theory, however ingenious, does not quite satisfy the de- 
 mands of strict mathematical reasoning. The secondary form of 
 some crystals, particularly, cannot very well be accounted for on 
 the supposition that they are formed by the piling upon one an- 
 other of the integrant molecules, although the objections made 
 against it by some philosophers, that the molecules would in 
 this case have spaces between them, can be but of little avail; 
 because there is no geometrical figure that the molecules 
 could possibly assume, which would not be more or less ob- 
 jectionable on this account. To wave these objections, Dr 
 Wollaston, one of the most ingenious philosophers of the 
 22* 
 
258 
 
 GENERAL REMARKS. 
 
 present age, has improved the theory of integrant molecules, 
 by showing the possibility of constructing both, the primitive 
 and secondary forms of crystals, by means of small integrant 
 spheres, as may be seen from the adjoining figures. 
 
 Fig. CXXIX. Fig. CXXX. 
 
 Fig. CXXXI. 
 
 Fig. CXXXII. Fig. CXXXIII. Fig. CXXXIV. 
 
 He supposes the intergant molecules of crystals to be 
 spheres, and the six primitive and all secondary forms of 
 bodies, produced by the piling upon one another of these 
 spheres. This theory is in many respects superior to Hauy's, 
 and although, as yet, far from being satisfactorily demonstra- 
 ted, deserves to be preferred to Hauy's for the following 
 reasons: 
 
 1. On account of its greater simplicity (adopting but one 
 from for all integrant molecules). 
 
 2. Because it seems to agree better with the general laws 
 of nature the spherical form being the most perfect of all, 
 containing (as may be proved mathematically) the greatest 
 quantity of matter, or space, bounded by the smallest surface ; 
 and it being the form which all bodies in nature spontaneously 
 assume, when solely acted upon by the cohesive attraction of 
 their particles. 
 
 3. Because all crystals are formed by bodies passing spon- 
 taneously from the liquid into the solid state ; and it is therefore 
 highly probable that the particles will adopt that arrangement 
 which is most natural. Moreover, it can be proved geometric- 
 ally, that if they are solely impelled by their gravitation 
 towards each other, they must arrange themselves round 
 
NITRATES. 259 
 
 their common centre of gravity, and consequently form 
 spheres. 
 
 Whichever theory we adopt, we must not forget that it is 
 but an ingenious hypothesis, which, although serving our im- 
 agination, is as yet far from being established by actual 
 experiment ; and it is more than probable that we shall never 
 be able to lift the veil with which nature covers all her works. 
 We can only worship and wonder at the simplicity of the 
 means which she adopts to produce the greatest ends ; but of 
 her secret operations we know nothing, either in this or any 
 other of the natural sciences. 
 
 We shall now proceed to describe the composition and prin- 
 cipal properties of those salts which are useful in common life, 
 and of some application in the arts. A comprehensive treatise 
 on this subject would fill volumes, and far exceed the limits 
 proposed in a work of an elementary nature. 
 
 236. The principal salts obtained from the combi- 
 nation of the acids with the different salifiable bases, are, 
 according to the nomenclature, explained in 232, the 
 Nitrates, Chlorates, Chlorides, Muriates (chlorides), Sul- 
 phates, Carbonates, Phosphates t Chromates, Arseniates, 
 Cyannites, and fulminates. 
 
 A. NITRATES. 
 
 237. Properties of the Nitrates. The combinations 
 of nitric acid with the various salifiable bases gives rise to 
 a class of salts extensively used in the arts. The general 
 properties by which they are distinguishable as a class, are 
 the following : 
 
 1. They are all decomposed by heat. 
 
 2. They are acted upon by all simple combustible sub- 
 stances. 
 
 3. They decompose the fixed acids. 
 
 4. They are soluble in water. 
 
260 NITRATE OF POTASH. 
 
 1. Nitrate of Potash (Nitre, Saltpetre). 
 
 Chemical Composition : I equiv. of nitric acid = 54 
 1 equiv. of oxide of potassium, or potash = 48 
 
 Consequently, chem. equiv. of nitrate of potash = 102. 
 
 < 238. This salt occurs in nature in the mineral and 
 vegetable kingdoms. It collects on damp walls, in sub- 
 terraneous places, in cellars, dirty lanes, and wherever 
 lime, potash, or decayed animal substances abound. It 
 is also obtained by neutralizing nitric acid with potash. 
 
 The nitre which occurs in commerce and which is used in 
 the manufacture of gunpowder, is obtained by throwing in heaps 
 the remains of decayed vegetable matter. Nitric acid is 
 by this means spontaneously generated by the decomposition 
 of these substances, which as we shall see hereafter, are 
 principally composed of nitrogen. Such heaps are called 
 nitre-beds. They must from time to time be sprinkled with 
 water, when after remaining in this state for several months, 
 nitre will be formed, in combination with nitrate of lime 
 and of magnesia. From these, and the earth with which it is 
 mixed, it is freed by dissolving it in water, and adding to the 
 solution a small quantity of potash, which decomposes the ni- 
 trates of lime and magnesia, and leaves the nitrate of potash 
 pure. The solution is afterwards evaporated and the nitre 
 obtained in crystals. 
 
 This mode of treating nitre is much resorted to in France 
 and particularly in Germany, for the manufacture of gunpow- 
 der ; but in England and this country nitre is imported from 
 the East Indies, where it is found already formed in a state of 
 efflorescence, particularly after heavy rains. 
 
 239. Properties of Nitre. It has a bitter (somewhat 
 sour,) cooling taste, is perfectly inodorous, becomes liquid 
 by igneous fusion ( 236), at a red heat, and becomes 
 decomposed at a still higher degree of temperature (its 
 acid being reduced to its elements, oxygen and nitrogen). 
 It crystalizes in 6 sided prisms. When mixed with 
 common salt (Chloride of soda) it becomes partly de- 
 composed, and nitrate of soda and chloride of potassium 
 are formed. Thrown upon red coals, it promotes their 
 combustion by giving off oxygen. A mixture of sulphur 
 
NITRATE OF POTASH. 261 
 
 and nitre thrown into a red hot crucible will immediately 
 burn with a vivid .light. A mixture of phosphorus and 
 nitre may be inflamed by the stroke of a hammer, with 
 great detonation. 
 
 Uses of Saltpetre. Nitre, or saltpetre is used princi- 
 pally, 
 
 1. In the preparation of fulminating powder. 
 
 2. In the manufactory of gunpowder. 
 
 3. In the manufactory of sulphuric acid. 
 
 4. In the manufactory of glass. 
 
 5. In medicine. 
 
 6. In domestic economy (for corning beef and preserv- 
 ing grain). 
 
 Three parts of nitre, two of potash, and one of sulphur, when 
 mixed together and heated, explode with a loud noise, on ac- 
 count of the great quantity of nitrogen which is suddenly giv- 
 en off. Hence the name fulminating powder. 
 
 240. Gunpowder. The most remarkable applica- 
 tion of nitre is in the manufactory of gunpowder. This 
 is a mixture of nitre, charcoal, and sulphur. The propor- 
 tions of these ingredients vary according to the purpose for 
 which the powder is to be used. It consists generally of 
 five parts of nitre, one part of sulphur, and one of charcoal. 
 These are moistened and finely powdered, either by wood- 
 en pestles, or, in modern times, by marble rollers, and the 
 paste thus obtained is then granulated and dried. 
 
 Table exhibiting different sorts of Powder. 
 
 INGREDIENTS. 
 
 nitre, sulphur, charcoal. 
 
 Prussian military powder, . . . 75 . 11.5 13.5 
 
 French and English, .75 12.5 12.5 
 
 English Dartfort, . . 79.7 7.82 12.48 
 
 Swedish, 76 9 16 
 
 Austrian musket powder, .... 72 16 17 
 
 Properties of good powder. It must have a bluish slate-color 
 (a dark or black color shows too great a proportion of charcoal, 
 or dampness). The grains must be round and even, and not 
 too readily crumble between the fingers. When ignited, the 
 whole must be quickly inflamed, without a crackling noise, and 
 
262 NITRATE OF SODA. 
 
 without singing- the surface on which it is placed. A yel- 
 low or black residue after combustion is a proof of too great a 
 proportion of sulphur or charcoal, and a crackling noise during 
 combustion shows that the powder is either damp or that there 
 are other salts mixed with the nitre. In order that gunpow- 
 der shall retain its qualities, it must be protected from damp- 
 ness. For this purpose it is best kept in leather bags. 
 
 Gunpowder ignites at a temperature of 419 Fahrenheit, 
 and its subsequent expansion and propelling power is owing 
 to a prodigious quantity of nitrogen, carbureted hydrogen, 
 and sulphurous acid gas in connection with a large propor- 
 tion of steam, which are given off instantaneously during 
 its combustion. The use and effect of powder are suffi- 
 ciently known. 
 
 The powder contained in the cartridges of common fire-arms 
 is never wholly ignited ; part of it is always expelled without 
 adding to the effect of the piece. By the use of percussion-caps 
 (see Fulminates) a more powerful stream of fire is created, in 
 consequence of which the powder ignites more thoroughly, 
 and it has been found upon experiment that a percussion-gun 
 produces the same effect with only four fifths of the quantity 
 of powder which is needed for the charge of a musket with a 
 common lock. 
 
 2. Nitrate of Soda. 
 
 Chemical Composition : 1 equiv. of nitric acid = 54 
 1 equiv. of soda (oxide of sodium) = 32 
 
 Consequently, chemical equiv. of nitrate of soda = 86 
 
 241. Nitrate of soda, also under the name of cubic 
 nitre, is found among native nitre in Spain, India, and 
 America, particularly in Peru, where layers of more than 
 two miles in length have lately been discovered. It may 
 also be produced artificially by saturating nitric acid with 
 soda. Its taste is cooling, pungent, and bitter, though 
 less so than that of nitrate of potash. It burns with an 
 orange-colored light, three times slower than powder, 
 wherefore it is used in fire-works. (Pyro-technia). 
 
NITRATE OF AM M ON I A. -OF LIME. 263 
 
 3. Nitrate of Ammonia. 
 
 Chemical Composition : 1 equiv. of nitric acid = 54 
 
 1 do. of ammonia = 17 
 
 to which is added 1 do. of water = 9 
 
 Consequently, chem. equiv. of nitrate of ammonia = 80. 
 
 242. This is a salt produced by dropping a so- 
 lution of ammonia into dilute sulphuric acid. It crys- 
 talizes in needles (four or six sided prisms) which have 
 a lustre like silk. They are colorless, have a bitter, cool- 
 ing, pungent taste, attract easily moisture from the atmos- 
 phere, explode when thrown on burning coals, and produce 
 great cold when dissolved in water. There is but little 
 or no use made of this salt in the arts. 
 
 4. Nitrate of Lime. 
 
 Chemical Composition : 1 equiv. of nitric acid = 54 
 1 do. of lime = 28 * 
 
 Consequently, chemical equiv. of nitrate of lead = 82. 
 
 243. Nitrate of lime occurs in small quantities in 
 well and pump water, and among the nitre which collects 
 on walls or on the surface of the earth. It is also produced 
 by dissolving a salt called carbonate of lime in nitric acid 
 (the lime combining with the nitric acid and the carbonic 
 acid being set free). It crystalizes in colorless, six-sided 
 prisms, attracts moisture from the air, and deliquesces (see 
 235). It is dissolved by one fourth its weight of cold 
 water, (in warm water it melts sooner) and by equal parts 
 of hot alcohol. Its taste is bitter, sharp and cooling. 
 When heated, it gives off oxygen gas, and the residue 
 emitting in the dark a white, beautiful light, is known by 
 the name of Baldwin's Phosphorus. It detonates weakly 
 when thrown on burning coals, and is chiefly used in the 
 preparation of saltpetre. 
 
264 NITRATES OF MERCURY, 
 
 5. Proto-nitrate and Per-nitrate of Mercury. 
 
 Chemical Composition. Proto-nitrate of mercury is 
 composed of 1 equivalent of nitric acid = 54 
 1. equivalent of protoxide of mercury = 208 
 
 Consequently, chem. equivalent of proto-nitrate 
 
 of mercury = 262. 
 
 Per-nitrate of Mercury 
 
 is composed of 1 equivalent of nitric acid = 54 
 2 equiv. of per-oxide of mercury (each = 21 6) = 432 
 
 Consequently, chemical equivalent of per-nitrate 
 
 of mercury = 486. 
 
 244. The proto-nitrate of mercury is a salt, which, 
 as we may suppose from its name, is composed of protoxide 
 of mercury and nitric acid. It is obtained by pouring 
 quicksilver upon weak dilute nitric acid, kept at a low 
 temperature. Oxide of nitrogen is slowly given off, and 
 a' colorless solution formed, which deposites colorless, 
 transparent crystals, of a sharp, pungent taste. When 
 exposed to daylight they become yellow, and stain the skin 
 with a purple color. 
 
 The per-nitrate of mercury is a combination of the per- 
 oxide of mercury with nitric acid. It is obtained in the 
 same manner as the proto-nitrate, only that the solution 
 must be heated and boil for some time. When the liquid 
 evaporates, long, prismatic crystals are formed, which 
 have a pungent, sharp taste, attract moisture, and be- 
 come yellow by exposition to day-light. Both nitrates of 
 quicksilver are used in medicine. They are also employ- 
 ed in the art of gilding by means of gold amalgams. 
 
 6. Nitrate of Silver. 
 
 Chemical Composition : 1 equiv. of nitric acid = 54 
 1 do. of oxide of silver = 118 
 
 Chemical equivalent of nitrate of silver = 172. 
 245. This salt, fused and cast into small bars, forms 
 
NITRATE OF SILVER OF LEAD. 265 
 
 the well known lunar caustic, extensively used in surgery. 
 It is obtained from a solution of fine silver in nitric acid. 
 Deutoxide of nitrogen is given off, and the nitrate shoots 
 into colorless, transparent crystals, which have a sharp, 
 hitler, metallic taste, and upon being exposed to light, 
 turn dark. It is dissolved in equal parts of cold water, 
 and in 4 parts of boiling alcohol. A number of bodies 
 have the power of decomposing it, and when mercury is 
 poured upon it, the silver is precipitated in form of a tree, 
 which affords one of the most beautiful and striking ex- 
 periments that can be made, to beginners. It destroys 
 speedily all vegetable and animal formations (hence its 
 use in surgery ), or stains them first with a white, but upon 
 exposition to light, with a permanent black color. The 
 latter property is taken advantage of in the preparation of 
 indelible or marking ink. 
 
 The linen or cotton which is to be marked is first moist- 
 ened with a solution of carbonate of soda, upon which, when 
 perfectly dry, the letters are written with a solution of ni- 
 trate of silver, mixed with gum arabic, and a little India 
 ink. Upon exposition to light, the letters turn permanently 
 black. 
 
 7. Nitrate of Lead. 
 
 Chemical Composition : 1 equiv. of nitric acid = 54 
 1 equiv. of protoxide of lead s= 112 
 
 Consequently, chemical equiv. of nitrate of lead = 166. 
 
 246. This salt is quickly obtained from a solution 
 of oxide of lead in nitric acid. It crystalizes in colorless, 
 transparent (sometimes white, opaque) octahedrons, which 
 have a pungent, cooling, sweetish taste. It is dissolved 
 in seven times its weight of cold water (much less boiling 
 water is required), melts when heated, gives off oxygen 
 and leaves oxide of lead. It is used in cotton-printing. 
 With Chromate of potassium it produces a beautiful or- 
 ange color. 
 
 23 
 
266 NITRATE OF COPPER-CHLORATES. 
 
 8. Nitrate of Copper. 
 
 Chemical Composition : 1 equiv. of nitric acid = 54 
 1 equiv. of per-oxide of copper = 80 
 
 Consequently, chem. equiv. of nitrate of copper = 134. 
 
 247. Nitrate of copper is obtained by dissolving 
 copper in dilute nitric acid. The salt crystalizes in prisms 
 of a beautiful sapphire-blue color, has a sharp, caustic 
 taste ; deliquesces ( 235) easily, and dissolves readily in 
 water. It is used in the preparation of blue colors in 
 cotton printing, and as a means of oxydizing metals. 
 
 B. CHLORATES. 
 
 <> 248. Properties of the chlorates. These salts are 
 in their properties similar to the nitrates. They are all 
 products of art, and are easily decomposed by heat. They 
 give off part of their oxygen and are totally consumed 
 when thrown upon burning coals. We shall only describe 
 a few of them. 
 
 Chlorate of Potash. 
 
 Chemical Composition : 1 equiv. of chloric acid = 76 
 I do. of potash = 48 
 
 Consequently, chem. equiv. of chlorate of potash = 124. 
 
 249. This salt is produced by conducting as much 
 chlorine into a solution of pure potash as the latter is ca- 
 pable of taking up. The solution is then suffered to cool 
 and evaporate, when the salts will shoot in crystals similar 
 in appearance to mother of pearl. 
 
 The solution of potash is placed in a three-necked bottle A, 
 
CHLORATE OF POTASH. 267 
 
 shaped as represented in the adjoining figure. This bottle 
 iff. CXXXV. 
 
 G R 
 
 communicates by means of a pipe, with the globe G, and the 
 retort R, into which some black oxide of manganese is intro- 
 duced in a state of fine powder. The apparatus being thus 
 arranged, muriatic acid is poured upon the oxide of manga- 
 nese through the safety tube T, which to prevent the immedi- 
 ate escape of the chlorine gas must be shaped as represented 
 in the figure, and a gentle heat applied to the retort. Chlorine 
 will be given off and pass over into the solution of potash, un- 
 til the solution is saturated, after which the excess of gas will 
 escape through the safety tube. When the saturated solu- 
 tion is afterwards evaporated at a low heat, small shining crys- 
 tals are obtained, which are the pure chlorate of potash. 
 
 250. Properties. Its taste is cooling but nauseous. 
 It is besides, inodorous, sparingly soluble in cold water, 
 becomes liquid by a gentle heat, but gives off its oxygen 
 and becomes decomposed by high temperatures. When 
 mixed with combustible substances a smart stroke or per- 
 cussion may inflame it, and a violent detonation takes 
 place. (Half a tea-spoon full wrapt in a piece of paper 
 and briskly struck with a hammer, gives a report like a 
 gun). It is used in the comstruction of instantaneous light 
 matches. 
 
 Instantaneous light matches. The ends of the matches are 
 covered with a red mass, consisting of 30 parts of chlorate of 
 potash, 10 of sulphur, and a little gum water. When these 
 matches are dipped in a little bottle, filled with concentrated 
 sulphuric acid, enough heat is produced for the sulphur to ig- 
 nite, that is, to combine with the oxygen which is given off. 
 
 REMARK. Bertholet, a French chemist, endeavored to use 
 chlorate of potash instead of nitre in the manufactory of gun- 
 
268 CHLORATE OP SODA OF AMMONIA. 
 
 powder. The powder thus obtained is very powerful, but so 
 highly inflammable that many people lost their lives during its 
 preparation, or in the attempt of packing or transporting it. 
 It is nevertheless used in fire-works, for the red light in thea- 
 tres, and in the construction of Congreve's rockets. 
 
 2. Chlorate vj Soda. 
 
 Cliemical Composition : 1 equiv. of chloric acid = 76 
 1 do. of soda = 32 
 
 Consequently, chemical equiv. of chlorate of sod a = 108. 
 
 251. Clilorate of soda is obtained in the same man- 
 ner as chlorate of potash (taking soda instead of potash). 
 It crystalizes in cubes, tastes almost like chlorate of pot- 
 ash, is soluble in three parts of cold (much less of warm) 
 water, but is more easily dissolved in spirits of wine. Its 
 other properties resemble those of nitrate of potash. 
 
 3. Hydro-chlorate (Muriate) of Ammonia. 
 
 Chemical Composition : 1 equiv. of muriatic acid = 37 
 
 1 do. of ammonia = 17 
 
 To this must yet be added, 1 equiv. of water = 9 
 
 Consequently, chemical equiv. of hydro-chlorate 
 
 of ammonia = 63. 
 
 5) 252. This salt, commonly called sal-ammoniac, is 
 found in all volcanic countries, in hair-like crystals, or 
 spherical ; also in form of a powder, colored by an admix- 
 ture of sulphur or oxide of iron. It is manufactured on a 
 large scale from the refuse of animal substances, (such as 
 hoofs, horns, claws, &c), and may also be obtained by 
 neutralizing a solution of ammonia with muriatic acid. 
 When the liquid is evaporated, the salt shoots in color- 
 less crystals, of a sharp, pungent, saline taste. It is easi- 
 ly volatilized, emits white vapors, and is very soluble in 
 water. It is used for a variety of purposes in the arts, 
 particularly in tinning copper ware, to prevent the oxida- 
 tion of that metal. 
 
CHLORIDE OF LIME. 269 
 
 . C. CHLORIDES. 
 
 253. Pure chlorine combines with potash, soda and 
 other oxides of metals. All these combinations have pow- 
 erful bleaching powers and smell after chlorine. The 
 most remarkable and useful of them is 
 
 Chloride of Lime. 
 
 Chemical Composition : 1 equivalent of chlorine = 36 
 2 equivalents of lirne (each = 28) = 56 
 
 Consequently, chemical equiv. of chloride of lime = 92. 
 
 ^ 254. This compound is manufactured upon a very 
 extensive scale. For this purpose chlorine is passed into 
 rooms in which fine-powdered, fresh-slacked lime is sub- 
 mitted to its action. The gas combines quickly with the 
 lime ; but as this combination is accompanied by an evo- 
 lution of heat, through which chlorate of lime would be 
 formed, it is necessary to let the gas slowly into the room, 
 commonly two days in succession) or to surround the room 
 with cold water. It is calculated that 1 cwt. of lime yields 
 commonly 1J cwt. of chloride of lime. 
 
 ^ 255. Properties. Dry chloride of lime is a white 
 powder with a faint smell of chloric acid (not chlorine) 
 and a strong, pungent taste. By long keeping, especial- 
 ly when moist, it absorbs carbonic acid gas from the at- 
 mosphere, whereby it becomes converted into carbonate of 
 lime. 
 
 Applications of Chloride of Lime. It is extensively 
 used in the process of bleaching, on which account it 
 is commonly called bleaching powder, and possesses 
 the remarkable property of cleansing the atmosphere 
 from the infective effluvia and exhalation of putrefying 
 substances, and communicating to it a pleasant freshness. 
 For this purpose fumigation and sprinkling with chloride 
 of lime cannot be too strongly recommended, in case of 
 contagious diseases in hospitals, prisons, alms-houses, and 
 all places of public assembly. 
 23* 
 
270 CHLORIDE OF SILVER. 
 
 D. MURIATES, (OR CHLORIDES). 
 
 256. Properties of the Muriates, or Chlorides. The 
 salts belonging to this class are all distinguishable by the 
 following characterizing properties : 
 
 1. They remain all unaltered by the admixture of com- 
 bustible substances (such as hydrogen, sulphur, carbon, 
 &c), to whatever degree of heat they may be exposed. 
 Common salt, for instance, which is a chloride of sodium, 
 may be mixed with charcoal and heated, without changing 
 in the least, its properties. 
 
 2. They are all decomposed by sulphuric acid, giving 
 off muriatic acid, &c. 
 
 3. They are all soluble in water. 
 
 REMARK. It is to be remarked that in regard to the com- 
 binations of muriatic acid with the different salifiable oxides 
 of metals, there are two different opinions entertained by mod- 
 ern chemists. Some of them believe that when muriatic acid 
 is poured upon an oxide of a metal, a mutual decomposition 
 takes place ; the chlorine of the acid combines with the metal 
 and forms a chloride, while the hydrogen of the muriatic acid 
 combines with the oxygen of the oxide to water, in which the 
 chlorine is afterwards dissolved. Hence the appellation of 
 chlorides. Others, however, take the solution of a metallic 
 oxide in muriatic acid, for a hydrate : believing the water 
 chemically combined with the solution. For this reason they 
 call the salts thence obtained, muriates. It is, of course, in- 
 different for practical purposes, to which of these two opinions 
 we adhere, and we shall therefore distinguish these salts in 
 future by the name of chlorides. 
 
 1 . Chloride of Silver. 
 
 Chemical Composition : I equivalent of chlorine = 36 
 1 do. of oxide of silver = 110 
 
 Consequently, chem. equiv. of chloride of silver = 146. 
 
 This salt has already been described in Chapter III, 184, 
 page 201, among the binary combinations of silver. 
 
CHLORIDE OF GOLD. OF PLATINUM. 271 
 
 2. Chloride of Gold. 
 Chemical Composition not precisely understood. 
 
 257. Chloride of gold is prepared from a solution of 
 gold in nitro-muriatic acid. The solution has commonly 
 a strong sour taste, ]ias a beautiful yellow color, and leaves 
 upon evaporation a reddish-yellow, saline mass, which still 
 contains some muriatic acid, and is soluble in water. If 
 this salt be gently heated, chlorine is given off, and its 
 yellow color is changed into red. Both the yellow and 
 the red salt deliquesce, have a sour, astringent, nauseous 
 taste, and are highly poisonous. They are easily soluble 
 in water, ether and alcohol. These solutions become de- 
 composed by exposition to daylight, (still better by solar 
 light) whereby gold is precipitated. The salts themselves 
 are likewise decomposed by light and heat, (chloride of 
 gold, and finally simple gold remains). The pure chloride 
 of gold is used in several preparations of gold ; in the man- 
 ufactury of gold-purple, a precious, beautiful color, em- 
 ployed in glass and porcelain painting, and particularly in 
 the gilding of steel, for which purpose it is extensively 
 employed. 
 
 3. Chloride of Platinum. 
 
 Chemical Composition : 2 equivalents of chlorine 
 
 (each = 36) = 72 
 1 equivalent of platinum = 96 
 
 Consequently, chern. equiv. of chloride of platinum = 168. 
 
 258. A DOUBLE Chloride (bichloride) of platinum 
 may be obtained by the solution of platinum in nitro-muri- 
 atic acid. When the solution is carefully evaporated a 
 blackish brown mass is obtained (as long as it contains 
 water it appears red) which has a nauseous, metallic, sharp 
 taste, acts as a poison on the animal body, and is easily 
 soluble in water, ether and alcohol. It communicates to or- 
 ganic substances a purple color, and when heated gives off 
 part of its chlorine, by which means a simple chloride of 
 
272 CHLORIDE OF COPPER. OF TIN. 
 
 platinum remains. This is a greyish powder, which is sol- 
 uble only in concentrated muriatic acid. 
 
 4. Chloride of Copper. 
 
 Chemical Composition : 2 equiv. of chlorine 
 
 (each = 36) = 72 
 1 equiv. of copper = 64 
 
 Consequently, chem. equiv. of chloride of copper = 136. 
 
 259. Double chloride of copper is obtained as a 
 hydrate by a solution of oxide of copper in muriatic acid. 
 In an an-hydrous state it may be obtained by being gently 
 heated. If the temperature be still further increased, part of 
 the chlorine is given off and the simple chloride of copper 
 remains. (An-hydrous chloride of copper may also be ob- 
 tained at once by heating thin plates of copper, and im- 
 mersing them in chlorine. The copper does then burn 
 with a green light, and the product of the combustion is 
 the an-hydrous chloride). The an-hydrous combination 
 has a yellowish brown color, but absorbs moisture so rap- 
 idly from the air that its color becomes soon changed into 
 green. Mixed with 35 per cent of water it crystalizes in 
 beautiful green needles, which have a sharp metallic taste, 
 deliquesce, and are easily dissolved by spirits of wine. 
 Such a solution burns with a beautiful green flame, and 
 is used in fire-works and for theatrical purposes. 
 
 5. Chloride of Lead. 
 
 This salt has already been spoken of, among the binary 
 combinations of lead, on page 214. 
 
 6. Chloride of Tin. 
 
 ^ 260. Chloride of Tin, ( Tin salt) is obtained in an 
 an-hydrous state ; when tin-filings are heated with mu- 
 riatic acid gas ; the hydrogen of the muriatic acid gas 
 is given off, and the chlorine combines with the tin. Jt is 
 a grey, half-transparent substance, of a glassy fracture, 
 which melts and becomes volatilized at a red heat. Chlo- 
 
CHLORIDE OF COBALT. 273 
 
 ride of tin combined with water (muriate of tin), is ob- 
 tained from a solution of tin-filings in muriatic acid. The 
 solution has a brown color, which upon cooling and con- 
 centrating, forms colorless, transparent crystals of a disa- 
 greeable taste and smell, and highly poisonous. They 
 deliquesce, and are easily soluble in water. Chloride of 
 tin is used in cotton and silk dyeing. 
 
 Per-chloridt of tin is obtained by a distillation of one part of 
 tin-filings with four parts of corrosive sublimate. Ttis a color- 
 less, transparent liquid, of a very disagreeable smell, which, in 
 contact with atmospheric air, emits dense white vapors. It 
 absorbs water rapidly. By adding to it one third of its weight 
 of water it becomes converted into a thick, white substance, 
 known by the name of tin-butter. 
 
 7. Chloride of Cobalt. 
 
 261. This chloride is produced by boiling a solution 
 of cobalt in concentrated muriatic acid. The solution has 
 a beautiful red color (when concentrated and warm it is 
 blue), and crystalizes with water in dark red prisms, which 
 have an astringent taste, and are soluble in water and al- 
 cohol. 
 
 A dilute, weak solution of chloride of cobalt, which is almost 
 colorless, is used for a sort of sympathetic ink. The charac- 
 ters written with it, when dry are invisible ; but when the 
 paper is held before a fire they become blue. Upon cooling, 
 the color disappears again ; but may again be produced by 
 exposition to heat. When the experiment is often repeated, 
 the characters become finally fixed with a dark red color. 
 
 Chlorine combines yet with iron, nickel, cerium, and 
 most of the other metals. 
 
 E. SULPHATES. 
 
 262. Properties of the Sulphates. These salts are 
 formed (as the name indicates) by the combination of sul- 
 phuric acid with the different salifiable bases. Many of 
 them are products of nature, and are of great usefulness 
 to the arts. They may be marked, as a class, by the fol- 
 lowing properties : 
 
274 SULPHATE OF POTASH. OF SODA. 
 
 1. When an acid is poured upon them, at common tem- 
 peratures, they neither effervesce nor give off any vapors. 
 
 2. They are all decomposed by high temperatures, with 
 the exception, however, of the sulphates of potash, soda, 
 lithia, baryta, strontia, lime, magnesia, and lead. 
 
 3. They are all decomposed by carbon under the influ- 
 ence of an intense heat. 
 
 1. Sulphate of Potash. 
 
 Chemical Composition : I equiv. of sulphuric acid = 40 
 1 do. of potash = 48 
 
 Consequently, chem. equiv. of sulphate of potash = 88. 
 
 263. This salt occurs in common stone or table salt, 
 in alumine. and in many vegetables. It is obtained, as 
 a secondary product in salines, and in the preparation of 
 nitric and sulphuric acid. It crystalizes in prisms, has a 
 sharp, bitter, saline taste, remains fixed in fire, and is sol- 
 uble in 12 parts of cold water. It is used in medicine, 
 and in the preparation of alum, glass, and saltpetre. 
 
 2. Sulphate of Soda. 
 
 Chemical Composition : \ equiv. of sulphuric acid = 40 
 1 do. of soda = 32 
 
 Consequently, chem. equiv. of sulphate of soda = 72. 
 
 264. This sulphate (known in medicine by the 
 name of Glauber's salts) occurs in all three kingdoms of 
 nature. It is sometimes (for instance, in Spain) found on 
 the surface of the earth, and adheres to damp walls. It is 
 also found in mineral waters, and in lakes. It is obtained 
 in large quantities by the decomposition of common salt 
 by means of sulphuric acid (whereby muriatic acid is given 
 off). It crystalizes in colorless, transparent prisms, which 
 have a bitter, cooling taste, and when exposed to the at- 
 mosphere, changes into a white powder, and deliquesce at 
 a gentle heat. This salt is not soluble in alcohol. It is 
 used in the artificial preparation of carbonate of soda and 
 in the manufactury of glass; but particularly in medicine. 
 
SULPHATE OF LIME. OF MAGNESIA. 275 
 
 3. Sulphate of Lime. 
 
 Chemical Composition : 1 equiv. of sulphuric acid = 40 
 
 1 do. of lime =28 
 
 to which are added 2 equiv. of water (each = 9) = 18 
 
 Consequently, chem. equiv. of sulphate of lime = 86. 
 
 265. Sulphate of lime occurs abundantly in the min- 
 eral kingdom, as gypsum, selenite, alabaster, and plaster- 
 stone ; more rarely in vegetable and animal substances. 
 Selenite crystalizes in right or oblique prisms, which are 
 transparent, and either colorless, or grey, yellow, or brown, 
 and have a lustre between glass and mother of pearl. 
 
 Mabaster has more of a lamellar texture, and a white, yel- 
 lowish-grey, or reddish color. The most compact kind of 
 gypsum, 
 
 Plaster-stone, contains often remains of animal and vegeta- 
 ble substances. It is very liable to destruction, and crumbles 
 easily into dust. 
 
 Gypsum may be produced by the action of sulphuric acid on 
 lime, in which case it is obtained in white, silky crystals, which 
 are not easily soluble in water. By burning, it becomes re- 
 duced to a white powder, called Plaster of Paris. The uses 
 of this salt are manifold. It serves to polish precious stones 
 and pearls, and is used for various ornaments (tables, clocks, 
 &c), for taking casts and moulds, for cements and stuccos in 
 architecture, in the manufactory of porcelain, and in domestic 
 economy as a manure for meadows and clover fields. Mixed 
 with animal glue, and polished with sand-stone, it resembles 
 marble. 
 
 4. Sulphate of Magnesia. 
 
 Chemical Composition : 1 equiv. of sulphuric acid = 40 
 1 do. of magnesia =20 
 
 Consequently, chemical equivalent of sulphate 
 
 of magnesia = 60. 
 
 266. Sulphate of magnesia (bitter salt, Epsomsalt) 
 is contained in sea and mineral waters, which on that 
 account have a bitter taste (Epsom, in England, whence 
 the name of the salt). It is also found in small quanti- 
 
276 SULPHATES OF MERCURY. 
 
 ties on the surface of the earth and in the ashes of burnt 
 vegetables. It may likewise be obtained by the action of 
 strong sulphuric acid on magnesia, by which much heat 
 is evolved (sometimes enough to cause ignition). It crys- 
 talizes in colorless, four-sided prisms, which are capable 
 of aqueous and igneous fusion, but forms, when exposed to 
 very high temperatures, a kind of enamel. This salt is 
 extensively used in medicine. 
 
 5. Sulphates of Mercury. 
 
 Sulphuric acid combines with the protoxide and per-ox- 
 ide of mercury (see Chap. Ill, 175, and 176) to proto- 
 sulphale and per-sulphate of mercury, respectively. 
 
 The Proto-sulphate of Mercury 
 
 is composed of 1 equivalent of sulphuric acid = 40 
 1 equivalent of protoxide of mercury =208 
 
 Consequently, chemical equiv. of proto-sulphate 
 
 of mercury = 248. 
 
 Per-sulphate of Mercury 
 
 is composed of 1 equivalent of sulphuric acid = 40 
 1 do. ofper-oxideofmercury = 216 
 
 Consequently, chemical equivalent of per-sul- 
 phate of mercury = 256. 
 
 267. Per-sulphate of mercury (from per-oxide of 
 mercury, is obtained by boiling 4 parts of quicksilver 
 with 5 parts of concentrated sulphuric acid. Sulphur- 
 ous acid gas is given off, and the liquid upon cooling 
 deposites a saline mass, in form of prismatic crystals. This 
 salt has a sharp, metallic taste, and is by the agency of 
 water, immediately separated into two distinct salts; in a 
 sour salt, which remains in a stale of solution, and in a 
 basic, which is precipitated. The basic salt has a yellow 
 color, but becomes black when exposed to solar light in a 
 state of moisture, on which account it cannot be used as a 
 dyeing stuff. 
 
SULPHATE OF SILVER. -OF COPPER. 277 
 
 The proto-sulphate of mercury is obtained by gently heat- 
 ing 1 one part of mercury, with one and a half parts of sulphuric 
 acid. It is but sparingly soluble even in warm water. 
 
 6. Sulphate of Silver. 
 
 Chemical Composition : I equiv. of sulphuric acid = 40 
 1 do. of oxide of silver = 118 
 
 Consequently, chem. equiv. of sulphate of silver = 158. 
 
 268. This salt is immediately obtained by a solution 
 of silver in concentrated sulphuric acid. It is with diffi- 
 culty soluble in water, crystalizes in small white needles, 
 has a metallic, disagreeable taste, and melts when heated, 
 by which means oxygen and sulphurous acid gas are giv- 
 en off, and pure metallic silver remains. Sulphate of silver 
 is formed whenever silver is separated from gold and copper 
 by means of sulphuric acid. The gold is not touched 
 by this acid and is therefore obtained in form of a powder. 
 The silver is recovered from the sulphate by the action of 
 copper, which combines with the acid and sets the silver 
 
 free. 
 
 
 
 7. Per-sulphate of Copper. 
 
 Chemical Composition : 2 equiv. of sulphuric 
 
 acid (each = 40) = 80 
 
 1 equiv. of per-oxide of copper = 80 
 
 to which is added 10 equiv. of water (each = 9) = 90 
 
 Consequently, chem. equiv. of per-sulphate of 
 
 copper = 250. 
 
 269. Per-sulphate of copper (blue vitriol) occurs, 
 in a state of solution, in copper-mines. It may be obtain- 
 ed also from a solution of copper in sulphuric acid. It 
 forms crystals of a beautiful azure color, which have a 
 disagreeable metallic taste, cause nausea and vomiting 
 when taken into the stomach, and become converted into 
 a white powder by exposure to heat. Blue vitriol is solu- 
 ble in water (not in spirits of wine). Various mixtures 
 
 24 
 
278 SULPHATES OF IRON-BARYTAAMMONIA. 
 
 of vitriol are used in the dyeing of wool, in the bronzing 
 of iron ware, in the coloring of gold, in medicine, &/c. 
 
 8. Sulphate of Iron. 
 
 Chemical Composition : 1 equiv. of sulphuric acid = 40 
 1 equiv. of protoxide of iron = 36 
 
 Consequently, chem. equiv. of sulphate of iron = 76. 
 
 270. Sulphate of iron (green vitriol) is a product 
 of nature, which is found in coal and other mines. It may 
 also be obtained from a solution of iron in dilute sulphu- 
 ric acid. It crystalizes in green, transparent rhombs, 
 which have a sour, astringent taste (like ink), and become 
 quickly oxidized in contact with atmospheric air. At 
 high temperatures it falls into a white powder. On ac- 
 count of its great affinity for oxygen it is used foj the des- 
 oxidation of indigo. 
 
 9. Sulphate of Baryta. 
 
 Chemical Composition : 1 equiv. of sulphuric acid = 40 
 I do. of baryta = 78 
 
 Consequently, chem. equiv. of sulphate of baryta= 118. 
 
 271. Sulphate of baryta (heavy spar) is found 
 crystalized in various shapes and forms. Its color is a 
 yellowish-white, grey, red, or blue, with a strong lustre 
 (like fat or glass). When heated with charcoal it fuses 
 at a high temperature into a white, opaque enamel. It is 
 used as a permanent white pigment, in the manufactory 
 of Wedgwood's jasper ware. 
 
 10. Sulphate of Ammonia. 
 
 Chemical Composition : 1 equiv. of sulphuric acid = 40 
 
 1 do. of ammonia = 17 
 
 to which is added 1 do. of water = 9 
 
 Consequently, chem. equiv. of sulphate of ammonia = 66. 
 272. This salt is obtained by neutralizing ammonia 
 
SULPHATE OF ALUMINE. 279 
 
 with sulphuric acid. It has a sharp, bitter taste, is soluble 
 in water, and is used in the manufacture of sal-ammoniac, 
 which may be prepared by subliming sulphate of ammonia 
 with common salt. It crystalizes in small prisms by tak- 
 ing up an additional equivalent of water, by which means 
 its chemical equivalent is increased from 66 to 75. 
 
 11. Sulphate of Alumine. 
 
 Chemical Composition : 1 equiv. of sulphuric acid = 40 
 1 do. ofalumine = 17 
 
 Consequently, chem. equiv. of sulphate of alurnine = 57. 
 
 273. This salt is a product of nature, and occurs in 
 America, in Guadaloupe, &c ; but is also obtained by art, 
 when pure alumine is dissolved in sulphuric acid. The 
 liquid, when evaporating, forms colorless, semi-transparent, 
 lamellar crystals, with an appearance like mother of pear]. 
 It has a sweet, astringent taste, is easily soluble in water 
 (not in alcohol), and gives off its acid when exposed to 
 heat. It combines with the sulphates of the alkalies, 
 arid forms thereby a class of salts with double bases, 
 well known by the name of alum. Thus, sulphate of alum- 
 ine combines with sulphate of potash, and forms a salt 
 which has two bases, alumine and potash. Again, sulphate 
 of alumine combines with sulphate of soda, the product 
 being a salt with the two bases, alumine and soda, and so 
 of the rest. 
 
 274. Alum. The two kinds of salt which we have 
 just chosen for an example, viz : sulphate of alumine and 
 potash, and sulphate of alumine and soda are by far the 
 most important kinds of alum. Both are products of nature ; 
 but the former (sulphate of alumine and potash) is met 
 with in much greater abundance, particularly in the neigh- 
 borhood of volcanos. They may also be obtained respect- 
 ively by pouring sulphate of potash or soda into a solution 
 of sulphate of alumine. The salts thence precipitated crys- 
 talize in octahedrons, have a sweet, astringent taste, and 
 are easily soluble in water. The acid of the first salt be- 
 comes decomposed by heat, whereby it becomes light and 
 
280 CARBONATE OF AMMONIA. 
 
 spongy, and is distinguished by the name of burnt alum. 
 The second salt is by heat entirely decomposed into its 
 elements. 
 
 Alum is an important article of commerce. It is used in 
 dyeing and calico printing, in tanneries and paper manufac- 
 tures ; for the sizing of paper. It is also extensively used in 
 medicine. 
 
 The sulphites are here omitted, because they are of less im- 
 portance to the arts, and their properties are not yet sufficient- 
 ly examined. 
 
 F. CARBONATES. 
 
 275. Characteristics of the Carbonates. The salts 
 of this class may be known by the following properties : 
 
 1. They lose their acid by exposition to heat (the car- 
 bonates of potash, soda and lithia alone excepted). 
 
 2. When mixed with charcoal they are all decomposed 
 by a high heat. 
 
 3. They are all decomposed by the acids, with strnog 
 effervescence of carbonic acid. 
 
 1. Carbonate of Ammonia. - 
 
 Chemical Composition : 1 equiv. of carbonic acid = 22 
 1 do. of ammonia = 17 
 
 Consequently, chem. equiv. of carbonate of ammonia= 39. 
 
 276. Two volumes of dry ammonia combine direct- 
 ly with one volume of carbonic acid gas. The product is 
 carbonate of ammonia, a white, crystaline substance, which 
 has a strong odor of ammonia, and is readily soluble in 
 water. In contact with the atmosphere part of the vola- 
 tile alkali (ammonia) escapes, whereby the remainder con- 
 tains a greater portion of the acid, and is therefore chang- 
 ed into bi (double) carbonate of ammonia. 
 
 Smelling Salts. Sesqui-carbonate (1^ carbonate) of ammo- 
 nia, also called smelling salts, is an important article of com- 
 merce. It is obtained on a large scale by subliming a mixture 
 of muriate of ammonia and chalk, or a mixture of the well- 
 known salt of hartshorn with animal charcoal (see Chap. II, 
 
CARBONATE OF POTASH. OF SODA. 281 
 
 page 124). From these mixtures it is produced in semi-transpa- 
 rent lumps, which have a pungent, penetrating taste and smell, 
 and are used in medicine. 
 
 A mixture of carbonate of ammonia and rancid mineral oil or 
 fat is obtained by dry distillation of animal substances, such as 
 bones, horns, hoofs, dried manure, &c, (all of which contain, 
 as we shall see hereafter, a great proportion of nitrogen). 
 The product thus obtained is called salts of hartshorn, and is a 
 yellowish brown salt of a penetrating, highly disagreeable 
 smell, which is used in medicine. 
 
 2. Carbonate of Potash. 
 
 Chemical Composition : 1 equiv. of carbonic acid = 22 
 1 do. of potash = 48 
 
 Consequently, chem. equiv. of carbonate of potash = 70. 
 
 277. This salt is obtained from the ashes of plants 
 growing remote from the sea-shore, which for this purpose 
 are dissolved in water, boiled, and afterwards calcined. 
 It constitutes the pot-ash and pearl-ash of commerce, and 
 is a solid, white mass, which is easily soluble in water, 
 melts at a red heat, and evaporates at a white heat. Its 
 taste is alkaline, but very little caustic. It is extensively 
 used in the manufactory of soap, in bleaching and dyeing, 
 and in glass making. 
 
 If carbonic acid gas is passed through a solution of carbon- 
 ate of potash, a bi-carbonate of potash is obtained, which crys- 
 talizes in great colorless crystals, and tastes yet a little alka- 
 line, but not caustic. By boiling and heating it part of the acid 
 is given off, arid the product is a ses^wi-carbonate of potash. 
 
 3. Carbonate of Soda. 
 
 Chemical Composition : 1 equiv. of carbonic acid = 22 
 1 do. of soda =32 
 
 Consequently, chem. equiv. of carbonate of soda = 54. 
 
 278. Carbonate of soda (soda-salt) is found, in a 
 state of solution, in some minerals. It is prepared on a 
 large scale, from the ashes of plants which grow near the 
 sea-shore, in a manner similar to that in which carbonate 
 
 24* 
 
282 CARBONATE OP MAGNESIA OF LIME. 
 
 of potash is obtained from the ashes of plants growing re- 
 mote from it. ( 277). It is a white, solid mass, similar 
 to carbonate of potash, only its taste is milder, and it is 
 more easily fusible in water. It forms colorless, transpa- 
 rent crystals which effloresce and undergo aqueous fusion. 
 It is used in the manufactory of glass, in dyeing, in calico- 
 printing, and in medicine. 
 
 The bi-carbonate and sesqui-carbonate of soda are obtained 
 from the carbonate in the same manner in which the bi-and ses- 
 qui-carbonate of potash are respectively obtained from carbon- 
 ate of potash. The sesqui-carbonate of soda is an abundant 
 product of nature, occurring particularly in Egypt, Hungary, 
 and South America. 
 
 4. Carbonate of Magnesia. 
 
 Chemical Composition : 1 equiv. of carbonic acid = 22 
 1 do. of magnesia = 20 
 
 Consequently, chern. equiv. of carbonate of magnesia = 42. 
 
 279. This salt occurs in large lumps in the East 
 Indies. It is also (though not so pure) obtained by adding 
 carbonate of potash to sulphate of magnesia, at a high tem- 
 perature. It is a white, inodorous, tasteless powder, which 
 is but sparingly soluble in water, but readily dissolved by 
 the acids. When a solution of it in dilute carbonic acid, 
 is suffered to evaporate, it crystalizes in small prisms, 
 which effloresce, are easily soluble in water, and are ex- 
 tensively used in medicine. Sir Humphrey Davy, mixed 
 this salt with flour to make the bread lighter and healthier 
 (40 grains of carbonate of magnesia to one pound of bread). 
 
 5. Carbonate of Lime. 
 
 Chemical Composition: 1 equiv. of carbonic acid = 22 
 I do. of lime = 28 
 
 Consequently, chem. equiv. of carbonate of lime = 50. 
 
 280. Carbonate of lime occurs native in huge 
 masses, forming whole chains of mountains. It is either 
 crystalized, as spar, or in a crystaline state, as white mar- 
 
CARBONATE OP BARYTA. OF LEAD. 283 
 
 bte ; hard, as lime-stone, or earthy, as chalk. It is also 
 found in the animal kingdom, in the shells of oysters, 
 snails, eggs, &c. That which is prepared by art is obtain- 
 ed from a solution of burnt oyster-shelis in muriatic acid. 
 It consists generally of a white powder, which is inodor- 
 ous, tasteless and insoluble in water ; but soluble in very 
 dilute carbonic acid, forming with it bi-carbonate of lime. 
 By a red heat it becomes decomposed, gives off its acid, 
 and becomes changed into lime. (This explains the 
 burning of chalk and lime-stone to lime). The stones 
 used in lithography are also a carbonate of lime. 
 
 6. Carbonate of Baryta. 
 
 Chemical Composition : 1 equiv. of carbonic acid = 22 
 1 do. of baryta = 78 
 
 Consequently, chem. equiv. of carbonate of baryta = 100. 
 
 281. Carbonate of baryta is likewise a product of 
 nature, and occurs as a distinct fossil in England (in the 
 the counties of Lancashire, Durham, Cumberland, &c), 
 in Hungary, and particularly in Siberia. It crystalizes in 
 semi-transparent, greyish white, sometimes greenish prisms, 
 but is also precipitated as a white, insoluble powder, from 
 a solution of baryta water, and carbonate of potash. It 
 has neither taste nor smell ; but is very poisonous. Mixed 
 with charcoal and exposed to a red heat ; it becomes de- 
 composed, whereby carbonic acid is given off, and caustic 
 baryta remains. 
 
 7. Carbonate of Lead. 
 
 Chemical Composition : 1 equiv. of carbonic acid = 22 
 1 do. of oxide of lead = ! 12 
 
 Consequently, chem. equiv. of carbonate of lead = 134. 
 
 282. This is a metallic ore, commonly called white 
 lead. It is manufactured on a large scale by exposing 
 sheet lead to the action of vinegar. In modern times it has 
 also been obtained as a precipitate, by adding carbonate 
 of potash ( 277) to nitrate of lead. It has a beautiful 
 
284 CARBONATE OF IRON. OF COPPER. 
 
 white color, is insoluble in water, but readily dissolves in a 
 solution of carbonic acid. It is extensively used as a 
 paint, on which account it is an important article of com- 
 merce. 
 
 8. Carbonate of Iron. 
 
 Chemical Composition : 1 equiv. of carbonic acid = 22 
 1 equiv. of protoxide of iron = 36 
 
 Consequently, chein. equiv. of carbonate of iron = 58. 
 
 283. This salt occurs as a natural product in some of 
 the iron ores, but may also be obtained as a precipitate 
 from a solution of sulphate of iron with carbonate of pot- 
 ash. The native carbonate forms white crystals ; that 
 which is produced by art is a greenish white powder, 
 which in contact with the atmosphere gradually loses its 
 acid, and changes its color into brown. It is inodorous, 
 tasteless, and insoluble in water, and is used in the manu- 
 factory of steel, and in the preparation of some artificial 
 mineral-waters. 
 
 '*; fi 9. Carbonate of Copper. 
 
 Chemical Composition : 1 equiv. of carbonic acid = 22 
 
 1 equiv. of per-oxide of copper = 80 
 
 to which is added 1 equivalent of water = 9 
 
 Consequently, chem. equiv. of carbonate of copper =111. 
 
 284. This carbonate occurs likewise native, as 
 Malachite, a beautiful green mineral, which is principally 
 used in the preparation of green and blue pigments. It 
 is also obtained, as a precipitate, from a mixture of sul- 
 phate of copper with carbonate of potash. The green 
 substance which is formed in copper and bronze vessels, 
 when exposed to a damp atmosphere, is a carbonate of the 
 same metal. 
 
 G. PHOSPHATES. 
 285. General characteristics of the Phosphates. 
 
PHOSPHATE OF AMMONIA. -OF SODA. 
 
 285 
 
 The salts belonging to this class are formed by the union 
 of phosphoric acid with the different salifiable bases, and 
 may easily be marked by the following characteristics : 
 
 1. They are not decomposed by a red heat, but melt at 
 higher temperatures. 
 
 2. They are, with the exception of the phosphates of 
 potash, soda, and ammonia, but sparingly soluble in water. 
 
 3. They are all dissolved without effervescence, by 
 phosphoric and nitric acid, from which they may again be 
 precipitated by an addition of ammonia. 
 
 1 . Phosphate of Ammonia. 
 
 Chemical Composition : 
 
 I equiv. of phosphoric acid = 28 
 1 do. of ammonia = 17 
 
 Consequently, chem. equiv. ofphosphate of ammonia= 45. 
 
 5 286. This salt occurs in some of the liquids of car- 
 nivorous animals, and rnay be prepared from carbonate of 
 ammonia and phosphate of lime . It has a pungent but 
 cooling taste, and is easily soluble in water. It is used 
 for the preparation of phosphoric acid. 
 
 2. Phosphate of Soda. 
 
 Chemical Composition : 
 
 1 equiv. of phosphoric acid = 28 
 1 do. of soda = 32 
 
 Consequently, chem. equiv. of phosphate of soda =60. 
 
 287. Phosphate of soda occurs likewise in animal 
 liquids. It may be obtained by neutralizing phosphoric 
 acid with carbonate of soda; crystalizes in colorless, 
 transparent rhombs, has a cold, saline (not bitter) taste, 
 effloresces in contact with the atmosphere, and when ex- 
 posed to an intense heat, undergoes first aqueous and af- 
 terwards igneous fusion (see 235). Combined with 
 phosphate of ammonia ( 286), it forms a salt with double 
 bases, known by the name of microcosmic salt, which may 
 be procured by dissolving muriate of ammonia and phos- 
 phate of soda in boiling water, and is used instead of borax 
 
286 PHOSPHATE OF LIME. 
 
 ( 120) for a variety of technical purposes. Phosphate of 
 soda is also used in medicine. 
 
 3. Phosphate of Lime. 
 
 Chemical Composition : 1 equiv. of phosphoric acid = 28 
 
 1 do. of lime = 28 
 
 to which is added 2 equiv. of water (each = 9) = 18 
 
 Consequently, chem. equiv. of phosphate of lime = 74. 
 
 288. Phosphate of lime is a principal ingredient of 
 the bones of animals, but is also contained in other solids, 
 and in some of the liquids of their bodies, as, for instance, 
 in milk, in the white of eggs, &,c. It is generally pro- 
 cured by the calcination of bones, and consists of a greyish 
 white powder, which soon dries to a hard lump. Jt is 
 easily soluble in nitric, muriatic, and phosphoric acid 
 and melts, when heated, to a mass which bears a strong 
 resemblance to porcelain. It is used for cleansing brass, 
 as a tooth powder, and in the manufactory of milk-glass 
 and porcelain. 
 
 Bi-phosphate of lime is obtained from a solution of phos- 
 phate of lime in any strong mineral acid. It forms crystals of 
 a lamellar texture, has a sour taste, deliquesces, is easily solu- 
 ble in water, and is used in the manufactory of phosphorus 
 and phosphoric acid. 
 
 The phosphites created by the union of phosphorus acid 
 with the different salifiable bases are here omitted j be- 
 cause they are of very little application in the arts or in medi- 
 cine. 
 
 H. CHROMATES. 
 
 289. Properties of the Chromates. The salts form- 
 ed by chromic acid in combination with the bases have all 
 a yellow orange-color, and afford, when mixed with potash 
 or soda through the influence of the blow-pipe, (see 
 chemical apparatus, page 26), a beautiful, green-colored 
 glass. 
 
CHROMATE OF POTASH. OF LEAD. 287 
 
 1. Chr ornate of Potash. 
 
 290. This salt is manufactured on a large scale in 
 Manchester and London, by heating one of the iron ores, 
 called chromate of iron, with an equal weight of nitre and 
 carbonate of potash. 1 equivalent of the chromic acid 
 which is thus formed, combines with 1 equivalent of pot- 
 ash to a salt which crystalizes in yellow, six-sided prisms, 
 has a bitter, disagreeable taste, melts at a red heat and be- 
 comes green. It is used in the preparation of chromic 
 acid, in the manufactory of several paints and pigments, 
 in calico printing, &/c. 
 
 2. Chromate of Lead. 
 
 291. 1 equivalent of chromic acid, combined with 
 1 equivalent of lead, occurs crystalized in the red ore of 
 lead. It is semi-transparent, and of a beautiful red (sel- 
 dom yellow) color. It may be produced by art, by pre- 
 cipitating nitrate of lead with chromate of potash ( 290). 
 It is a tasteless, inodorous powder, which is in soluble in 
 water and unchangeable by light or air. It may be used as 
 a pigment, in calico-printing and in oil-painting. 
 
 3. Chromate of Mercury. 
 
 292. Chromate of mercury is obtained by precipi- 
 tating nitrate of mercury with chromate of potash. It pos- 
 sesses a beautiful orange-color, is insoluble in water, but 
 readily dissolved in nitric acid, and is used as a red pig- 
 ment. 
 
 t. ARSENIATES AND ARSENITES. 
 
 293. Characteristics of the Arseniates and Arsenites. 
 These salts possess the following general properties : 
 
 1. They are insoluble in water (the arseniates of potash, 
 soda, and ammonia alone excepted). 
 
 2. They are all decomposed when heated with charcoal 
 
 3. They are all readily dissolved in arsenic and nitric 
 acid. 
 
288 ARSENITE OF POTASH. -OF COBALT. 
 
 1. Arsenite of Potash. 
 
 294. This combination of arsenious acid with potash 
 is produced by boiling until neutralization a solution of 
 carbonate of potash with powdered arsenious acid. The 
 salt thus obtained deliquesces so easily that it has not as 
 yet been obtained in crystals. A thick solution of it is 
 yellow, has a disagreeable smell, and is highly poisonous. 
 It is used in calico-printing, and in small quantities even 
 in medicine. 
 
 2. Arsenite of Cobalt. 
 
 295. Arsenite of cobalt occurs as a red ore of cobalt, 
 or may be prepared by the action of double affinity (see In- 
 troduction XVIII), from arsenite of potash ( 294) on any 
 salt of cobalt. (The cobalt of the salt separates the arsen- 
 ious acid from the potash and combines with it to a neu- 
 tral salt). It is a red powder which gives a blue color to 
 glass or clay, is decomposed by heat, and dissolves in am- 
 monia to a liquid of a dark red color. 
 
 K. CYANITES AND FULMINATES. 
 
 296. Cyanites and Fulminates. We have already 
 spoken of the combinations of cyanogen with oxygen 
 (Chap. II, 89), the products of which are cyanous and 
 fulminic acid. 
 
 Fulminic acid (only discovered in 1824) occurs no 
 where in nature, but may be formed by mixing nitrate of 
 mercury or silver with alcohol at a high temperature. Al- 
 cohol and nitric acid are given off, and the remaining ni- 
 trogen, oxygen, and carbon form fulminic acid. This, 
 however, is mixed with other substances, and all attempts 
 to isolate the acid, or to obtain it in a pure state have 
 hitherto failed. The salts of this acid, which are called 
 fulminates, have the remarkable property, not possessed by 
 the cyanates or cyanites, of detonating and exploding at 
 the slightest friction, or in contact with concentrated sul- 
 phuric or nitric acid. These salts are now used in the 
 
RECAPITULATION. 289 
 
 manufactory of percussion caps, instead of the locks of fire- 
 arms. 
 
 The cyanous acid forms with the different bases cyanites, 
 which, by heat, are easily decomposed into ammonia and 
 carbonic acid. 
 
 REMARK. The cyanic acid is composed of the same ele- 
 ments and united in the same proportion as those of fulminic 
 acid, and yet the properties of its salts (the fulminates) are 
 entirely different from those of the fulminates (formed by ful- 
 minic acid). The reason of this difference is not sufficiently 
 accounted for. 
 
 We might speak of the bromates, sodates, hydro-brom- 
 ates, and almost an infinite number of other salts; but 
 we have proposed only to treat of those which are of fre- 
 quent application in common life, and with which it is ab- 
 solutely necessary to be acquainted, to understand even 
 the most ordinary processes of the arts. 
 
 RECAPITULATION. 
 
 Questions for Reviewing the most important Principles 
 contained in Chapter IV. 
 
 A. QUESTIONS ON THE GENERAL REMARKS ON THE 
 SALTS. 
 
 [ 227.] What two elements are by far the most pow- 
 erful agents in nature 1 What is the product of their 
 union ? What are all bodies in relation to oxygen and 
 hydrogen 1 
 
 Give examples. 
 
 [ 228.] What are the most remarkable products ob- 
 tained by the combination of oxygen and hydrogen with 
 other substances ? What is the body called which in com- 
 bination with oxygen or hydrogen forms an acid 1 What 
 is the oxygen or hydrogen called ? What is the acidifying 
 
 25 
 
RECAPITULATION 
 
 principle in nitric acid 1 What is the acidifying principle 
 in muriatic acid? 
 
 What is the electro positive, and what the electro-negative 
 factor in an acid ? 
 
 [ 229.] What are those acids called into whose com- 
 position hydrogen enters as the acidifying principle 1 
 What acids belong to this class? 
 
 What do many other acids require for their liquid form ? 
 What are those acids called ? What word have they pre- 
 fixed to their names ? What are those acids called in 
 which water does not enter as an essential ingredient? 
 
 [ 230.] What class of bodies do the acids form when 
 combined with those substances called bases ? How then 
 is a salt defined ? 
 
 What occurs when a salt is decomposed by the agency 
 of the galvanic pile? What do we infer from this fact? 
 
 What is the opinion of some philosophers in reference to all 
 chemical phenomena ? By whom is this theory supported ? 
 Can you state any facts which may serve to corroborate this 
 theory ? 
 
 Explain experiment I, represented in Fig. CXV. 
 
 How is this phenomenon accounted for by the electric attrac- 
 tion of the battery ? 
 
 Explain experiment II, represented in Fig. CXVI. 
 
 What do we see from this experiment ? 
 
 What takes place, if, in your last experiment, a solution of 
 sulphate of soda is placed in the cup connected with the nega- 
 tive or copper pole, and in the other two a solution of red cab- 
 bage ? Is the result different if the middle cup be filled with 
 an alkaline solution ? 
 
 Now what do these experiments prove ? 
 
 [ 231.] What sort of bodies are all the salifiable ba- 
 ses with the exception of ammonia ? Are organic bodies 
 capable of becoming salifiable bases ? How are the bases 
 therefore divided ? What bases in the mineral kingdom 
 are easily soluble in water ? Which are not easily soluble ? 
 Which bases are insoluble in water ? How are the organic 
 bases again divided ? 
 
 Why may the salts be considered as quarternary combina- 
 tions of the elements ? 
 
OF CHAPTER IV. 291 
 
 [ 232.] What does each of the acids form, in union 
 with the salifiable frases ? After what are the different 
 salts thus produced, commonly denominated 1 Into what 
 is the denomination of the acid in ic changed? Into what 
 is that terminating in ous changed ? Give examples. 
 What do you call the salt which arises from the combination 
 of sulphuric acid with soda 1 What, that which is formed 
 by sulphurows acid with ammonia 1 
 
 Is the nomenclature of salts advantageous or not ? What 
 does the appellation of each salt show ? 
 
 [ 233.] How have the different salts yet been divid- 
 ed. What do you understand by a neutral salt ? What 
 by a sour ; what by a basic salt ? 
 
 [ 234.] What do all salts which are obtained in form 
 of crystals contain? What is the water called, which is 
 mechanically entangled ? What that which is chemically 
 combined ? What do all salts which contain water me- 
 chanically entangled, when thrown into fire? What is 
 this owing to ? Does the same happen with the salts which 
 contain water as a chemical ingredient? 
 
 [ 235.] What do some salts lose at common tempera- 
 tures of the atmosphere 1 What are they then said to do ? 
 What do you understand by the phenomenon of deliques- 
 cence ? What do you call the process by which a salt 
 is melted by heat, without being decomposed ? What, 
 that, when a salt melts in its own water, if the solving 
 power of the water is increased by heat. 
 
 Questions on Crystalography. 
 
 What takes place when a body, from a state of solution, 
 is converted into a solid, so that its particles are capable of 
 following their own mutual attractions? What is it then 
 called ? What important discovery did Haiiy make, with re- 
 gard to the division of crystals ? What peculiar geometrical 
 forms did he discover were no longer divisible without fracture? 
 What is this geometrical form called, which is, as it were, the 
 nucleus of the crystal ? What is the shape called, which the 
 crystal has before the division ? 
 
 To how many regular geometrical solids are the primitive 
 forms of all crystals reducible ? (Call the different geometri- 
 
292 RECAPITULATION 
 
 
 
 cal solids, represented in Figs. CXVII, CXVIII, CXIX, CXX, 
 CXXI, CXXII, CXXIII, CXXIV). 
 
 To what three solids are these six, again reducible by math- 
 ematical division ? What, therefore, is the opinion of some 
 philosophers respecting the primitive form of crystals ? What 
 are these three solids called? 
 
 By what means may any prism whatever be divided into tri- 
 angular prisms ? How may the rhombic dodecahedron be 
 formed by integrant cubes? (Explain Fig. CXXVIII). 
 What is Dr Wollaston's theory respecting the integrant 
 molecules of crystals ? (Explain Figs. CXXIX, CXXXIV). 
 
 In what respect is this theory superior to Hauy's ? 
 
 [ 236.] What are the names of the principalsalts 
 according to their nomenclature after the acids ? 
 
 A. QUESTIONS ON THE NITRATES. 
 
 [ 237.] What are the principal properties of the ni- 
 trates ? 
 
 [ 238.] What is the chemical composition of nitrate 
 of potash ? Where does this salt occur ? By what means 
 may it be obtained artificially ? 
 
 How is nitre produced in France and Germany for the man- 
 ufacture of gunpowder ? 
 
 [ 239.] What are the principal properties of nitre ? 
 In what consists the chief use of nitre ? 
 
 [ 240.] What is the most remarkable application of 
 nitre ? Of what ingredients does gunpowder generally 
 consist 1 
 
 What are the properties of good gunpowder ? 
 
 At what temperature does gunpowder ignite ? To what 
 is its subsequent expansion and propelling power owing ? 
 
 [ 241.] What is the chemical composition of nitrate 
 of soda? Where does this salt occur? How may it be 
 produced artificially? What are its properties? For 
 what purposes is it used ? 
 
 [ 242.] What is the chemical composition of nitrate 
 
OF CHAPTER IV. 293 
 
 of ammonia? How is this salt produced? What are its 
 properties 1 
 
 [ 243.] What is the chemical composition of nitrate 
 of lime? Where does it occur? How may it be produ- 
 ced ? What form does it assume by crystalization ? What 
 are its properties 1 
 
 [ 244.] What is the chemical composition of proto- 
 nitrate of mercury 1 What, that of per-nitrate of mercury ? 
 
 How is the proto-nitrate of mercury obtained ? How is 
 the per-nitrate obtained ? For what purposes are both 
 nitrates used ? 
 
 [ 245.] What is the chemical composition of nitrate 
 of silver? By what other name is this salt known, when 
 fused and cast into small bars ? How is it obtained ? 
 What are its properties ? 
 
 How is nitrate of silver used as indelible or marking ink ? 
 
 [ 246.] What is the chemical composition of nitrate 
 of lead? How is this salt obtained ? What are its prop- 
 erties ? For what purposes is it used ? 
 
 [ 247.] What is the chemical composition of nitrate 
 of copper ? How is it obtained ? What are its proper- 
 ties? 
 
 B. QUESTIONS ON THE CHLORATES. 
 
 [ 248.] What are the principal properties of the 
 chlorates ? 
 
 [ 249.] What is the chemical composition of the 
 chlorate of potash ? How is this salt produced ? 
 
 Explain the experiment represented in Fig. CXXXV. 
 
 [ 250.] What are the characterizing properties of 
 chlorate of potash ? For what is it used ? 
 
 How are instantaneous light-matches constructed ? For what 
 purposes did Bartholet, a French chemist, endeavor to use this 
 salt ? For what purposes is it, nevertheless, used ? 
 
 25* 
 
294 RECAPITULATION 
 
 [ 251.] What is the chemical composition of chlo- 
 rate of soda ? How is it obtained ? What are its prop- 
 erties ? 
 
 [ 252.] What is the chemical composition of hydro- 
 chlorate of ammonia ? What is this salt commonly called ? 
 Where is it found 1 From what is it manufactured ? By 
 what means may it also be obtained 1 What are its prop- 
 erties ? 
 
 C. QUESTIONS ON CHLORIDES. 
 
 [ 253. What property have all the salts belonging to 
 the class of chlorides? 
 
 [ 254.] What is the chemical composition of chloride 
 of lime? How is this salt manufactured ? 
 
 [ 255.] What are the properties of chloride of lime ? 
 What are the applications of chloride of lime? 
 
 D. QUESTIONS ON THE MURIATES (CHLORIDES). 
 
 [$ 256.] By what properties are the muriates distin- 
 guished ? 
 
 What different opinions exist with regard to the muriates ? 
 What is the chemical composition of chloride of silver? 
 
 [ 257.] How is chloride of gold prepared ? What 
 are its properties ? For what purposes is it used ? 
 
 [ 258.] What is the chemical composition of chloride 
 of platinum ? How is the double chloride (bi-chloride) of 
 platinum obtained ? What are its properties ? How is the 
 simple chloride of platinum obtained? 
 
 [ 259.] What is the chemical composition of chlo- 
 ride of copper ? How is double chloride of copper obtain- 
 ed ? How is the simple chloride of copper obtained from 
 the double chloride ? How may the an-hydrous chloride 
 of copper be obtained ? What are its properties ? 
 
OF CHAPTER IV. 
 
 295 
 
 [ 260.], By what means is chloride of tin obtained? 
 What are its properties 1 For what purposes is it used ? 
 
 How is the per-chloride of tin obtained ? What are its 
 properties ? Into what does it become converted when mixed 
 with one third of its weight of water? 
 
 [ 201.] How is chloride of cobalt produced ? What 
 are its properties ? 
 
 For what may a weak solution of chloride of cobalt be used ? 
 
 E. QUESTIONS ON THE SULPHATES. 
 
 [ 262.] By what characterizing properties are the 
 sulphates distinguished, as a class of salts 1 
 
 [ 263.] What is the chemical composition of sul- 
 phate of potash ? Where does this salt occur ? How is it 
 obtained ? What are its properties 1 
 
 [ 264.] What is the chemical composition of sulphate 
 of soda ? By what other name is this salt yet known in 
 medicine ? Where does it occur ? By what means is it 
 obtained in large quantities 1 What form does it assume by 
 crystalization 1 What are its properties 1 Where is it used 1 
 
 [ 265.] What is the chemical composition of sulphate 
 of lime? Where does it occur? In what form does it 
 crystalize ? 
 
 What are the properties of alabaster ? What is the most 
 compact kind of alabaster ? 
 
 What are the properties of plaster-stone ? 
 
 How may gypsum be produced ? By what process does it 
 become reduced to plaster of Paris ? What are the uses of 
 this salt?' 
 
 [ 266.] What is the chemical composition of sulphate 
 of magnesia ? In what is this salt contained ? Where is 
 it also found in small quantities ? By what means may it be 
 produced by art ? What are its properties ? 
 
 [ 267.] What is the chemical composition of proto- 
 sulphate of mercury ? What that of per-sulphate of mer- 
 cury ? How is the per-sulphate of mercury obtained ? 
 
296 RECAPITULATION 
 
 What are its properties ? Into what two salts is this salt 
 decomposed by the agency of water 1 What are the prop- 
 erties of the basic salt ? As what is it used ? 
 How is proto-sulphate of mercury obtained ? 
 
 [ 268.] What is the chemical composition of sulphate 
 of silver ? How is this salt obtained? What are its prop- 
 erties 1 
 
 [ 269.] What is the chemical composition of per-sul- 
 phate of copper ? Where does it occur ? From what may 
 it be obtained ? What properties do the crystals possess 
 which it forms ? For what purposes are they used ? 
 
 [ 270.] What is the chemical composition of sulphate 
 of iron 1 Where is this salt found 1 What are its prop- 
 erties ? 
 
 [ 271.] What is the chemical composition of sulphate 
 of baryta ? Where is it found ? What are its properties 1 
 
 [ 272.] What is the chemical composition of sulphate 
 of ammonia? How is this salt obtained? What are its 
 properties ? 
 
 [ 273.] What is the chemical composition of sulphate 
 of alumine ? What sort of product is it? How is it ob- 
 tained by art ? What are its properties ? With what sub- 
 stances does it combine? What class of salts does it 
 thereby form ? Give an example. 
 
 [ 274.] What two salts are the two most impor- 
 tant kinds of alum ? What sort of products are they ? 
 Which of the two is met with in greatest abundance ? By 
 what other means may they be obtained ? What are its 
 properties ? How is burnt alum obtained ? 
 
 For what purposes is alum used in the arts ? 
 
 F. QUESTIONS ON THE CARBONATES. 
 
 [ 275.] What are the general characteristics of the 
 carbonates ? 
 
 [5} 276.] What is the chemical composition of carbon- 
 
OF CHAPTER IV. 297 
 
 ate of ammonia ? What is the product of the combustion 
 of two volumes of dry ammonia with one volume of car- 
 bonic acid called 1 What properties does it possess? 
 
 By what name is the sesqui-carbonate (l^-carbonate)of am- 
 monia known in commerce ? How is it obtained? In what 
 shape ? What properties does it possess ? From what sub- 
 stances is salts of hartshorn obtained ? What are its proper- 
 ties ? 
 
 [ 277.] What is the chemical composition of carbon- 
 ate of potash ? How is this salt obtained ? What are its 
 properties ? 
 
 How is bi-carbonate of potash obtained ? What are its 
 properties ? Into what does it become converted by boiling 
 and heating ? 
 
 [ 278.] What is the composition of carbonate of soda? 
 Where is it found ? How is it prepared by art ? What 
 are its properties ? What sort of crystals does it form ? 
 For what purpose is it used ? 
 
 How are the bi-carbonate of sesqui-carbonate of soda ob- 
 tained ? What sort of product is the sesqui-carbonate of soda ? 
 
 [ 279.] What is the chemical composition of carbon- 
 ate of magnesia? Where does this salt occur ? By what 
 means may it be obtained by art ? What are its properties ? 
 By what process can it be made to crystalize ? For 
 what purpose did Sir Humphrey Davy use this salt ? 
 
 [ 280.] What is the chemical composition of carbon- 
 ate of lime ? Where, and in what quantities does it occur ? 
 In what animal substances is it also found ? How is it 
 prepared by art ? What are its properties ? Into what 
 does it become converted by a red heat ? What sort of 
 compound are the stones used in lithography ? 
 
 [ 281.] What is the chemical composition of carbon- 
 ate of baryta ? What sort of product is it ? Where does 
 it occur ? What are its properties ? What becomes of it 
 when mixed with charcoal and exposed to a red heat? 
 
 [ 282.] What is the chemical composition of carbon- 
 ate of lead ? By what other name is this salt yet known ? 
 
298 RECAPITULATION 
 
 How is this compound manufactured ? What are its 
 properties ? For what purposes is it extensively used ? 
 
 [ 283.] What is the chemical composition of carbon- 
 ate of iron ? Where does this salt occur ? How may it 
 be obtained by art 1 What are the properties of the natu- 
 ral product ? What those of the product, of art ? 
 
 [ 284.] What is the chemical composition of carbon- 
 ate of copper 1 Where does it occur ? How may it be 
 produced by art ? Of what consists the green substance 
 formed on the surface of copper and bronze vessels when 
 exposed to a damp atmosphere ? 
 
 G. QUESTIONS ON THE PHOSPHATES. 
 
 [ 285.] What are the general characteristics of the 
 phosphates ? 
 
 [ 286 ] What is the chemical composition of phos- 
 phate of ammonia 1 Where does it occur ? What are its 
 properties ? 
 
 [ 287.] What is the chemical composition of phos- 
 phate of soda ? Where does it occur ? What are its 
 properties ? What does it form in combination with phos- 
 phate of ammonia ? How may microcosmic salt be pro- 
 duced 1 
 
 [ 288.] What is the chemical composition of phos- 
 phate of lime 1 Where does it occur ? How is it gene- 
 rally produced ? For what purposes is it used ? 
 
 How is the bi-phosphate of lime obtained ? What are its 
 properties ? 
 
 H. QUESTIONS ON THE CHROMATES. 
 
 [ 289.] What are the characterizing properties of 
 chromates ? 
 
 [ 290.] How is the chromate of potash manufactured 
 in Manchester and London? What are its properties? 
 for what purposes is it used 1 
 
OF CHAPTER IV. 
 
 299 
 
 [ 291.] What salt does I equivalent of chromic acid, 
 combined with 1 of .lead, form 1 How may the same salt 
 be produced by art ? What are its properties ? 
 
 [ 292.] How is the chromate of mercury obtained ? 
 I. QUESTIONS ON THE ARSENIATES ARD ARSENITES. 
 
 [ 293.] By what characteristics are the arseniates and 
 arsenites distinguished ? 
 
 [ 294.] How is arsenite of potash produced ? What 
 are its properties ? For what is it used ? 
 
 [ 295.] Where does arsenite of cobalt occur ? What 
 are its properties ? 
 
 K. QUESTIONS ON THE CYANITES AND FULMINATES. 
 
 [ 296.] Does fulminic acid occur in nature in its 
 simple form ? How then may it be produced ? What 
 are the salts, formed by this acid in combination with the 
 different salifiable bases called? What remarkable prop- 
 erty do all these salts possess ? For what particular pur- 
 pose are these salts now used ? 
 
 What kind of salts does cyanous acid form when combined 
 with the different salifiable bases ? 
 
 Of what elements is cyanic acid composed ? 
 
300 GENERAL REMARKS 
 
 CHAPTER V. 
 
 VEGETABLE CHEMISTRY. 
 
 General Remarks on the Difference between Organic and 
 Inorganic Matter. 
 
 297. In animated nature plants and animals the 
 elements of matter seem to obey different laws from those 
 to which they are subjected in dead matter ; the products 
 of their combinations bearing little resemblance to those 
 which are obtained in inorganic chemistry. Every living 
 body may be considered as a laboratory, in which a varie- 
 ty of chemical processes serve to support life, in such a 
 manner that from a simple atom, it is gradually developed 
 to its highest perfection ; after which these processes begin 
 to be carried on more slowly, and finally cease entirely. 
 From that moment the body obeys all the laws of inani- 
 mate matter. Such is the life and death of every plant and 
 animal. The time from the beginning to the cessation of 
 life (death) is various ; but all bodies endowed with life, in 
 whatever shape they may appear to us, go through the two 
 periods of gradual perfection and decay. 
 
 ^ 298. Difference between organic and inorganized 
 matter. The difference between organic and inorganic 
 nature consists, therefore, principally in this : The organ- 
 ized body has a dejinite beginning and development, after 
 which it is subject to decay and death ; inorganic matter, 
 on the contrary, continues to exist (although sometimes in 
 different shapes) in whatever situation it may be placed. 
 
ON ORGANIC AND INORGANIC BODIES. 301 
 
 It is true, the inorganic elements of plants, and elements 
 (with which we shall presently become acquainted) are not 
 perishable ; but the particular nature of these bodies is, through 
 death, irrecoverably destroyed, and returns no more. The life 
 of the plant or animal is, consequently, not seated in the or- 
 ganic elements ; but in something higher, in a directing agent, 
 which is altogether different from, and superior to chemical 
 affinity, or any other attribute of matter. This inconceivable 
 agent the vital principle of nature is, by the divine wisdom 
 of the Creator, distributed throughout our globe with such won- 
 derful diversity, and so eminently well calculated for the sup- 
 port of man, that the destroyed organization of one being gives 
 birth and support to another ; by which means they are able 
 to succeed eacli other with infinite order and regularity ; each 
 fulfilling the end for which it was created. 
 
 299. In inorganic chemistry, we are generally able 
 to produce substances from their elements we can pro- 
 duce water from oxygen and hydrogen, the acids from 
 a combination of the acidifying principle with the radicals, 
 the salts from the acids and the salifiable bases ; but 
 this is totally impossible with regard to plants or animals. 
 No one has, as yet, succeeded, and certainly never will 
 succeed, to form a plant or an animal from its chemical 
 elements. These bodies need even for their support, 
 products of organized matter, as proper materials for the 
 chemical processes subservient to their existence. The 
 vegetable creation of one year subsists on the residue 
 of vegetable matlers from the preceding year ; grass-eating 
 animals need plants, carnivorous animals meat of other an- 
 imals, for their nutriment, or food. 
 
 300. Organs origin of the appellation of organized 
 bodies. The chemical processes of plants and animals 
 take place in certain vessels which seem to be created for 
 that purpose. These vessels are called organs, whence 
 the bodies themselves are said to be organized. 
 
 Of the manner in which these processes are carried on, we 
 are, with a few exceptions, almost entirely ignorant. Neither 
 do we know if the different elements, which we have discov- 
 ered in plants and animals, are actually chemically combined 
 with each other, or whether they exist in them only in a state 
 of mixture. 
 
 26 
 
302 GENERAL REMARKS 
 
 301. The products of vegetables which are used in 
 domestic economy and in the arts, are either situated in 
 particular organs, or are diffused throughout the whole 
 plant. When they are seated in particular organs, (as, 
 for instance, in the root, stalk, leaves, husk, seeds, &c), 
 they may easily be collected ; but when they are diffused 
 throughout the whole plant, certain processes such as 
 washing, drying, distilling, &c, are required to separate 
 them from the substances with which they are mixed. 
 More than thirty different vegetable products have in this 
 manner been obtained ; the most important of which we 
 shall speak of in the course of this treatise. 
 
 302. Immediate ingredients of Plants. The imme- 
 diate ingredients, which are obtained by the chemical 
 analysis of plants, are 
 
 1st. Certain gaseous substances, such as oxygen, hydro- 
 gen, nitrogen, carbonic acid gas, &c. These substances 
 have already been described in the preceding chapters. 
 
 2d. Substances which partake more or less of the liquid 
 state. To these belong mucilage, vegetable extract, 
 resin, &-c. 
 
 3d. Solid substances, as, for instance, woody fibre, fa- 
 rina, fruit, &c. 
 
 303. The liquid and solid parts of plants may again 
 be decomposed by the action of water, the acids, and the 
 oxides of the mineral kingdom, or by exposure to a high 
 heat. The elements resulting from their decomposition, 
 which may be considered as the more remote ingredients 
 of plants (see Introduction, VII), are either entirely com- 
 bustible^ that is, such as become, by heat, entirely con- 
 verted into gases, or Jixed vegetable alkalies, which, when 
 ignited and submitted to the highest temperatures, leave 
 still a certain quantity of ashes, which is no longer reduci- 
 ble by heat.* 
 
 For an illustration of what has just been advanced, we will 
 give but two examples : The juice, which is the first liquid 
 
 * This property they share with some of the oxides and salts ; 
 hence the name vegetable alkali. 
 
ON ORGANIC AND INORGANIC MATTER. 303 
 
 ingredient of grapes, may be decomposed into mucilage, sugar, 
 extract, coloring matter, tanning principle, and vegetable acid. 
 Farina, which is the immediate ingredient of wheat, may be 
 further reduced to starch, sugar, mucilage and woody fibre, veg- 
 etable extract, oxide, and salt. These are, therefore, the more 
 remote ingredients of wheat. 
 
 A knowledge of both kinds of ingredients, but more es- 
 pecially of the combustible ones, is indispensable to a cor- 
 rect understanding of the nature of plants, as well as their 
 application to chemical, technical and medicinal purposes. 
 
 304. But the more remote ingredients of vegetables, 
 decomposed into their ultimate principles exhibit but three 
 or four elements, of which, then, the whole infinite variety 
 of plants is composed ! ! These are oxygen, hydrogen, 
 carbon, and nitrogen (in a few cases only, phosphorus, 
 sulphur, iodine, and bromine) ; and from the different 
 proportions in which these few substances unite and com- 
 bine with each other, result the infinite variety of taste, 
 smell, color, &c, in the products of the vegetable king- 
 dom. 
 
 305. All vegetable matters may, with regard to their 
 composition, be divided into four great classes : 
 
 1. Into unsaleable vegetable substances; that is, such 
 as do not combine with the acids to form salts (see 
 Chap. IV). 
 
 2. Into salijiable bases ; that is, substances which, like 
 the oxides of metals, form salts in combination with the 
 acids. 
 
 3. Vegetable acids. These affect vegetable colors like 
 the mineral acids (see Introduction, 38) ; change blue 
 litmus paper into red, and with the mineral oxides or vege- 
 table bases form salts. 
 
 4. Substances nf an undetermined nature, which are not 
 comprised by either of the three preceding classes. 
 
 I. UNSALIFIABLE VEGETABLE SUBSTANCES. 
 
 306. The unsalifiable vegetable substances may 
 again be divided into neutral and watery. Neutral are 
 
304 WOODY FIBRE. STARCH. 
 
 those in which the hydrogen is to the oxygen as in wa- 
 ter ; that is, in the proportion of one to eight (see Chap. 
 1, 25). Watery, on the contrary, are those which 
 possess a greater quantity of hydrogen than, in combina- 
 tion with the oxygen they contain, is necessary to form 
 water. Their hydrogen, therefore, is to their oxygen in a 
 larger proportion than one to eight. 
 
 A. NEUTRAL UNSALIFIABLE VEGETABLE SUBSTANCES. 
 
 307. The most remarkable neutral unsalifiable sub- 
 stances in the vegetable kingdom are the woody Jibre, 
 starch, gum or mucilage, and sugar. When perfectly pure 
 they are all white, inodorous, and, with the exception of 
 sugar, tasteless. They are all solid, insoluble in pure al- 
 cohol, and burn with an acid smoke, which reddens litmus 
 paper. 
 
 1. Woody Fibre. 
 
 308. This principal ingredient of all plants, but more 
 especially of trees, is obtained by removing all soluble 
 parts from wood ; which is done by boiling it for a consid- 
 erable time in water, and then exposing it with alcohol to 
 a gentle heat. 
 
 Properties. It is white, inodorous, tasteless, and spe- 
 cifically lighter than water. It is insoluble in water, al- 
 cohol, or any diluted acid. Hence the fitness of hemp, 
 flax, and cotton to be bleached with water and chlorine. 
 Concentrated nitric, sulphuric, or muriatic acid destroys 
 it or gives it a yellowish brown color. Concentrated sul- 
 phuric acid blackens it, and with the assistance of heat 
 converts it into charcoal. When burnt in close vessels 
 (dry distillation) it affords tar and vinegar or acetic acid. 
 
 2. Starch. 
 
 309. Starch is obtained principally from all kinds of 
 grain ; but also from roots and a variety of other vegeta- 
 
GUM OR MUCILAGE. SUGAR. 305 
 
 ble substances (particularly from potatoes), by grinding 
 them to powder, and washing them frequently with cold 
 water. When dissolved in hot water it forms a kind of 
 glue or paste, used by bookbinders. It is soluble also in 
 the acids, and when boiled in a solution of sulphuric acid, 
 a sort of sugar (sugar of starch) is obtained.* Heated in 
 close vessels it yields a sort of vinegar, similar to, though 
 not exactly the same as that obtained from the dry distilla- 
 tion of woody fibre ( 308). 
 
 3. Gum or Mucilage. 
 
 310. Mucilage or gum occurs in different plants 
 and their organs, and is used for technical and phar- 
 maceutical purposes. When the substance is fluid, it is 
 termed mucilage ; when it occurs in a solid state it is called 
 gum. 
 
 Properties. Both are easily soluble in water, in solu- 
 tions of pure alkalies, and in diluted acids. Gum, howev- 
 er, is much harder and more brittle than mucilage. By 
 strong sulphuric acid it may be decomposed into water, 
 acid and charcoal. By the action of nitric acid it is con- 
 verted into Mucous acid, an acid peculiar to mucilaginous 
 substances, (which has not, as yet, been obtained from any 
 other body in nature), hence the name. When distilled 
 in a retort it yields, likewise, a sort of vinegar (acetous 
 acid). 
 
 4. Sugar. 
 
 311. This substance, which is known by its sweet 
 taste, solubility in water, and capacity of yielding (when 
 properly treated) spirituous liquors, may be obtained from 
 several plants, from fruit, carrots, raisins, liquorice, manna, 
 honey, &/c ; but more especially from the sugar-cane. The 
 pithy substance of this well known plant of southern climes 
 contains a sweet juice, which, with a small addition x of 
 slaked lime, is evaporated in copper vessels until it be- 
 
 * The same sugar is obtained spontaneously in the germination of 
 grains. 
 
 26* 
 
306 ESSENTIAL OILS. 
 
 comes thick and tenacious. This mass, upon cooling, 
 shoots into white crystals, which are afterwards separated 
 from the liquid. The crystals occur in commerce as raw 
 sugar ; the remaining liquid is filled in hogsheads and 
 sold as molasses. The raw sugar is afterwards again dis- 
 solved in lime-water and refined by bullocks' blood, which, 
 in the process of boiling, floats on top and draws all impu- 
 rities with it. The liquid is then cast into moulds, and 
 upon cooling, forms the loaf-sugar of commerce. Sugar 
 obtained in this manner is easily soluble in cold, but 
 much better in warm water ; from a solution of which it 
 crystalizes in prisms, which are called candied sugar. 
 Distilled with nitric acid, it becomes converted into oxalic 
 acid( which will be described hereafter) ; but when strong- 
 ly heated with it, into acetic acid and charcoal. Its ap- 
 plication in domestic economy and medicine is sufficiently 
 known. 
 
 B. WATERY UNSALIFIABLE VEGETABLE SUBSTANCES. 
 
 312. These occur either already formed by nature, 
 or are prepared by a process of art. To the former belong 
 the volatile or essential oils, the fat oils, wax, resin, &,c ; 
 to the latter, alcohol and the various kinds of ether. All 
 these substances are more or less fusible and soluble in 
 pure alcohol. On account of the great quantity of hydro- 
 gen which they contain, they are highly combustible, and 
 nerve, on this account, for fuel and light. 
 
 1. Volatile or Essential Oils. 
 
 313. These oils are distinguished by a strong, pen- 
 etrating smell, and an acrid taste. They are obtained from 
 the greatest variety of vegetable organs, viz : from flowers, 
 fruits, wood, leaves, roots, &/c, and differ much from each 
 other in color, taste, smell, fluidity, and combustibility (as, 
 for instance, the oils of camomile, of cloves, of peppermint, 
 of wax, of cinnamon, &c) ; most of them, however, pos- 
 sess the following properties : They have generally a yel- 
 low color and a sharp taste ; they boil more easily than 
 
FAT OILS. 307 
 
 water, are readily soluble in alcohol, (less so in water), 
 burn spontaneously when mixed with nitric acid ; and yield, 
 as the product of their combustion, a resinous substance, 
 or an acid. They thicken, when exposed for a long time 
 to the atmosphere, on account of the oxygen which they 
 absorb. By dry distillation in close vessels they are de- 
 composed, and yield principally carbureted hydrogen and 
 charcoal (see 84 and 73). They are used for the 
 preparation of odoriferous waters, for spice, essences, 
 drinks, &/c. 
 
 Camphor, which, although in a solid state, belongs like- 
 wise to the essential oils, is not inflamed by nitric acid, 
 but is converted into a distinct acid, which is called Cam- 
 phoric acid. It is capable of crystalization ; burns with 
 an aromatic smoke, and in combination with the alkalies 
 and oxides, forms a class of salts, which have received the 
 appellation of Camphorates. 
 
 2. Fat or Fixed Oils. 
 
 314. These oils, which are obtained by mechanical 
 pressure, from certain vegetables, differ from each other ac- 
 cording to the nature of the plant from which they are pro- 
 cured ; hence the different properties of olive-oil, linseed- 
 oil, nut-oil, oil of almonds, &>c. With the exception of co- 
 coa-butter, they are all liquid, have a yellow color, a faint, 
 sweetish taste, and when perfectly pure, are destitute of 
 smell. They are all specifically lighter than, and insoluble 
 in water. They are decomposed by dry distillation, and 
 combine with the alkalies to soap. All of them are highly 
 inflammable, and eminently calculated for combustion. 
 On account of the two last mentioned properties they are 
 valuable articles of domestic economy. 
 
 When the fixed oils are mixed with lamp-black, charcoal, 
 cotton, flax or wool, enough heat is given off to produce, in 
 some instances, spontaneous combustion. The greatest pre- 
 caution therefore ought to be used in cotton-mills, and in all 
 other machineries where oil comes in contact with charcoal or 
 oil. 
 
308 RESINS. 
 
 3. Resins. 
 
 315. The name of resins has been applied to the 
 thickened juices of trees, which exude from the incisions 
 or apertures made in their bark. To this class of bodies 
 belong the gum-resins,* aaafcctida, gum-ammoniac, aloes, 
 gamboge, myrrh, copal, dragon's blood, sandarach, turpen- 
 tine, common resin, caoutchouc or India rubber, amber, and 
 a variety of other substances. 
 
 Most resins have a yellow color, and are, in a pure state, 
 perfectly inodorous. Their taste is bitter ; they are easily 
 fusible; but not soluble in water, although readily dissolved 
 in spirits of wine, naphta, the fixed oils and the alkalies. 
 They burn with a dense smoke, emitting a very disagree- 
 able odor, and possess the remarkable property of becom- 
 ing electric by friction. (These phenomena have been 
 treated of in Natural Philosophy, Chapter VIII). The 
 gum-resins are extensively used in medicine. Common 
 resin is employed for physical and technical purposes, viz : 
 for varnishes, electrical machines, salves, balsams, &c. 
 
 India rubber or gum clastic is obtained principally from 
 two trees (the Hoevea Caoutchouc and Satropha Elastica) 
 which grow in Brazil. When an incision is made in the 
 bark of these trees, a milky juice exudes, which, in contact 
 with the atmosphere, becomes soon changed into a solid, 
 elastic substance, in which state it occurs in commerce. 
 It is supposed to contain a considerable quantity of nitro- 
 gen, burns with a bright flame, is insoluble in water, but 
 dissolves in ether and the volatile oils. It possesses the 
 invaluable property of rendering cloth, leather, and other 
 substances used as wearing apparel, impervious to water. 
 It is on this account used for over-shoes, for water-proof 
 boots, and such similar purposes. It absorbs also the 
 marks made with lead-pencil upon paper, and is on this ac- 
 count an indispensable article to the artist and draftsman. 
 
 REMARK. But few of the resinous substances have as yet 
 been thoroughly examined ; their ingredients and the propor- 
 tion in which they are combined are, therefore, far from being 
 satisfactorily known. 
 
 * So called from their apparent similarity to gum. 
 
WAX. ALCOHOL. 309 
 
 4. Wax. 
 
 316. This substance is obtained from vegetable 
 matter (berries, leaves, &c), as well as from bees. It 
 differs from resin by its greater fusibility, ductibility, and 
 peculiar smell. It is not so easily soluble in ether, or al- 
 cohol, as resin. It melts at about 150 Fahrenheit, and 
 forms a transparent fluid, which, as it cools, gradually ac- 
 quires consistency, and finally returns to the solid state. 
 Upon decomposition it is found to contain 82 per cent of 
 carbon, and 13 per cent of hydrogen ; consequently, 95 
 per cent of combustible elements. This circumstance 
 accounts sufficiently for the pure, bright flame of wax can- 
 dles, preferred, sometimes, even to those of the fixed oils. 
 
 5. Alcohol. 
 
 317. This substance, the product of fermentation 
 of all sugary parts of plants, is contained in a greater or 
 less quantity in all spirituous liquors, and produces their 
 well-known intoxicating effects. It is considerably lighter 
 than water, and its specific gravity affords a proof of its 
 rectification, and the rectification of other spirits. (The 
 lighter they are the less water is contained in them ; the 
 greater, therefore, is the quantity of water they contain).* 
 
 Alcohol, when pure, is perfectly colorless, has a pe- 
 culiar strong, penetrating smell, a burning taste, and is 
 easily volatilized. It boils at a much lower temperature 
 than water (at 176 Fahrenheit), but has not, as yet, been 
 made to congeal by any known method of producing arti- 
 ficial cold. Even mixed with water it requires several de- 
 grees below zero (over 35 below the freezing point of 
 water) to freeze it. It unites chemically with water, evolv- 
 ing considerable heat during the combination. It is high- 
 ly inflammable, absorbs most of the gases, and dissolves 
 many of the vegetable acids, volatile oils, resins and bal- 
 
 * Upon this principle are founded the wine, beer and brandy 
 scales (see chemical apparatus, Fig;. LVI and LVII, pages 33 35) 
 which exhibit the strength of these liquors by the depth to which 
 they immerse in them. Hence the appellation of 1st, 2d, 3d, 4th, 
 and 5th proof. 
 
310 ETHER AND NAPHTA. 
 
 sams. It acts also on iodine, sulphur, phosphorus, some 
 of the alkalies, and some of the salts (chloride of lime, sul- 
 phate of iron, and some of the nitrates). // preserves veg- 
 etable and animal substances from putrefaction ; but is 
 itself decomposed, when passed through a red hot copper 
 tube, into a fine, light soot, resembling lamp-black, and a 
 great quantity of carbureted hydrogen, (one ounce of al- 
 cohol yielding several cubic feet of carbureted hydrogen). 
 
 Uses of JllcohoL Alcohol is used in a great number of 
 preparations for domestic, technical, and medicinal purposes ; 
 and yet this highly important substance is composed of the 
 same elements, as all vegetable matters we have thus far de- 
 scribed ; which proves how much depends upon the proportion 
 in which simple bodies combine. Thus, while woody fibre con- 
 sists of 4 equivalents of carbon and 4 of water ; starch of 4 
 equivalents of carbon and 6 of water, and sugar of 4 equiva- 
 lents of carbon and 8 of water, alcohol consists of 4 equivalents 
 of carbon and 12 of water. The ratio, therefore, in which 
 carbon unites with water in these four substances is as 1 to J, 
 1 to 1^-, 1 to 2, and 1 to 4 ; and in these different proportions 
 alone lies the reason of the immense difference in the proper- 
 ties of woody fibre, starch, sugar, and alcohol ! ! 
 
 The process of Fermentation will be described hereafter 
 (Chap. VII), under the head of spontaneous decomposition of 
 organic substances. 
 
 6. Ether and Naphta. 
 
 318. When alcohol is distilled with the different acids, 
 it becomes converted into Ether, a liquid which is lighter 
 than alcohol, mixes in all proportions with the volatile oils, 
 and dissolves wax, resin, vegetable extracts and acids, and 
 some of the alkalies. After distillation a yellowish liquid 
 remains, which, when purified with a solution of potash, 
 will float on top, and is called oil of wine. This combines 
 again with the acids, and forms a class of substances 
 known by the name of Naphtas. Both products, the ethers 
 and naphtas, are strongly odoriferous, extremely volatile, 
 similar to the volatile oils, but more easily converted into 
 vapor, more inflammable, and specifically lighter than al- 
 cohol. The different kinds of ether are distinguished 
 from each other by prefixing the name of the acid from 
 
SALIFIABLE VEGETABLE BASES. 311 
 
 which they are derived. Thus, the ether prepared from 
 alcohol and sulphuric acid is called sulphuric ether ; that 
 which is obtained frdm muriatic acid and alcohol, is called 
 muriatic ether, and so of the rest. A similar nomencla- 
 ture has been adopted for the naphtas. 
 
 Sulphuric ether is by far the most important substance 
 of them all, and extensively used in medicine. It is ob- 
 tained by distilling together equal volumes of alcohol and 
 sulphuric acid. 
 
 II. SALIFIABLE VEGETABLE BASES. 
 
 319. This class of vegetable substances, the result 
 of the discoveries of modern chemists, contains about 30 
 different bodies, extracted mostly from narcotic and me- 
 dicinal plants, by the action of magnesia.* They are 
 generally white, have a sharp, bitter taste, may be obtain- 
 ed in crystals or as a powder, and change, when burnt or 
 in a state of moisture, red vegetable colors into blue. 
 They are not easily soluble in water, better in ether, but 
 most readily in alcohol. With the acids, (particularly the 
 sulphuric, nitric, and muriatic acids) they form salts which 
 are soluble in water, and easily decomposed by potash. 
 Their ultimate principles are oxygen, hydrogen, carbon, 
 and nitrogen ; the latter element only in a proportion of 
 from 4 to 8 per cent. Many of them are poisonous or 
 affect the animal body. 
 
 The salts which these bases form in combination with 
 the acids, are denominated after the acids according to 
 the rules laid down in Chapter IV, 232. 
 
 * The names are, Nicotine, Chinine, Cinchonine, Gentianine, 
 Daphnine, Corydaline, Zanthopicrite, Hesperidine, Guaranine, 
 pure bitter extract, Morphium, Opium (Narcotine), Picrotoxine, 
 Strychnine, Brucine, Solanine, Coffeeine, Narcotic extract, Delphi- 
 nine, Veratrine (Sabadi(line), Emetine, Piperin, Plumbagin, Ja- 
 maicin, Surinamin, jlsparagin, Olivil, and several other organic 
 bases, whose existence, however, is not yet sufficiently proved. 
 
312 TARTARIC ACID. 
 
 '.'* - . t 
 
 III. VEGETABLE ACIDS. 
 
 [In these substances the hydrogen is to the oxygen in a less 
 proportion than is necessary to form water ; that is, in a less 
 proportion than 1 to 8. (Compare 25, page 75).] 
 
 320. Characteristics of vegetable acids. The vege- 
 table acids are easily distinguished from the neutral or 
 salifiable vegetable substances, by their sour taste, by 
 changing the blue colors of vegetables into red, and by 
 their combination with the oxides of the mineral and vege- 
 table kingdoms. They are either capable of crystalization 
 (fixed), of distillation (liquid), or of sublimation (volatile). 
 They occur either already formed, in particular organs of 
 plants, or as salts, combined with inorganic or organic 
 bases, and are of great application in domestic economy, 
 in medicine and in the arts. 
 
 A. FIXED VEGETABLE ACIDS. 
 
 321 . The vegetable acids belonging to this class 
 are generally white, and easily soluble in water. The most 
 remarkable among them are Tartaric acid, Citric acid, 
 Malic acid, Gallic acid y Vegetable jelly and humous acid, 
 (in several roots, berries and in potatoes). 
 
 1. Tartaric Acid. 
 
 3*22. This acid occurs, in its simple form, in tama- 
 rinds, in grapes, pine-apples and pepper. It may also be 
 obtained from the well-known salt, cream of tartar (tar- 
 tarate of potash) by boiling it with an admixture of chalk, 
 white marble or oyster-shells. The tartarate of lime 
 thence obtained as a precipitate is gently heated with oil 
 of vitriol, the liquid afterwards evaporated to thickness, and 
 decanted from the sulphate of lime (gypsum) which falls 
 to the bottom. This liquid, upon further evaporation, or 
 upon cooling, forms regular, prismatic crystals, of a strong 
 acid taste, which are easily soluble in water, and fusible. 
 They unite with the different alkaline and earthy bases, 
 

 CITRIC ACID. -MALIC ACID. 313 
 
 and form a class of salts known by the name of tartrates. 
 The most remarkable among them is the tartrate of pot- 
 ash or vegetable salt, which is formed by neutralizing tar- 
 tar with carbonate of potash ; and the 
 
 Bi-tartrate of potash or tartar is a solid substance, spon- 
 taneously deposited by all kinds of wine, which by being 
 dissolved, filtered, and treated with clay, yields the cream 
 of tartar, from which tartaric acid is prepared. 
 
 2. Citric Acid. 
 
 323. This occurs in its simple form, or mixed with 
 malic acid (see the following section) in a variety of fruits. 
 It may also be procured by the action of nitric acid or 
 chlorine on many organic compounds. The way in which 
 it is commonly obtained is by saturating boiling lemon or 
 lime juice with carbonate of lime (see Chap. IV, 280). 
 To the citrate of lime thus obtained, boiling water and oil 
 of vitriol is added, and the liquid afterwards filtered and 
 evaporated until the acid is obtained in form of crystals. 
 Citric acid becomes spontaneously decomposed and cover- 
 ed with a scum, even in closed vessels, and slowly heated 
 with alcohol it becomes converted into vinegar.* The 
 salts formed by the combination of citric acid with the 
 different salifiable bases are called citrates. 
 
 3. Malic Acid. 
 
 324. This acid is next to acetic acid, and oxalic acid 
 (see 334 and 325) most generally distributed in the 
 vegetable kingdom, and occurs in the roots, stalks, blos- 
 soms, and fruits of a great many plants. It is generally 
 extracted from the berries of the sorb or service tree. It 
 is liquid, soluble in water, but crystalizes only with great 
 difficulty. It undergoes spontaneous decomposition, and 
 is by nitric acid converted into oxalic acid. The salts of 
 this acid are called malates. 
 
 * Gmehlen's Chemistry, Heidelberg, 1830. 
 
 27 
 
314 OXALIC, GALLIC, AND PECTIC ACIDS. 
 
 4. Oxalic Acid. 
 
 325. The mode of obtaining oxalic acid has already 
 been described in 324. It has a strong, sour taste, 
 changes blue vegetable colors into red, and forms, upon 
 evaporation, regular crystals, which by a red heat are 
 again decomposed, and leave nothing but charcoal. They 
 are soluble in water and boiling alcohol. With the dif- 
 ferent mineral bases they form a class of salts, which are 
 distinguished by the name of oxalates. The principal 
 ones are oxalate of potash, soda, lime, strontia, ammonia, 
 baryta, and magnesia. 
 
 5. Gallic Acid. 
 
 326. Gallic acid is contained in all astringent veg- 
 etable substances, particularly in the bark of trees; and is 
 chiefly obtained by dissolving powdered gall-nut in water, 
 at a gentle heat ; when the liquid is filtered and exposed 
 to the atmosphere it is covered with a thin scum, which 
 from time to time must be removed. When evaporated 
 to about half its volume it is decanted. The sediment is 
 then again digested with water and the same process is 
 repeated several times. The residue is afterwards dis- 
 solved in hot water, from which, upon cooling and filtering, 
 the acid shoots in regular crystals. 
 
 Gallic acid has a sharp, sweetish (not sour) taste. When 
 sublimed it reddens litmus paper ; melts, at a gentle heat, 
 to a colorless oil, and evaporates, when heated, with white 
 fumes and a faint smell, leaving nothing but a little char- 
 coal. When saturated with carbonate of potash or muri- 
 ate of tin a yellowish precipitate is formed, which is known 
 by the name of tan, and is used in the preparation of 
 leather. Gallic acid is a principal ingredient of writing 
 ink. 
 
 6. Vegetable Jelly, or Pectic acid. 
 
 327. This acid is obtained from the tremulous, soft 
 substance deposited by the juice of certain fruits. It may 
 be purified by decanting the juice and washing it with a 
 
BITUMOUS ACID.-BENZOIC ACID. 315 
 
 little cold water. It appears, when dry, in transparent 
 leaves, which do not adhere to the sides of the vessel 
 has, when moist, a decidedly sour taste, and reddens litmus 
 paper. It combines readily with the alkalies and other 
 salifiable bases. 
 
 7. Bitumuus Acid* 
 
 328. Bitumous acid is produced from turf, mineral 
 pitch, bituminous wood, mold and such similar substan- 
 ces, by dissolving them in liquid potash and precipitating 
 the solution by the addition of some other acid. The acid 
 thus obtained appears in brown flakes, but when perfectly 
 dry it is a brown, brittle mass, of great lustre. By dry 
 distillation it becomes decomposed into carbonic acid, car- 
 bureted hydrogen gas, water, oil, and acetic acid. 
 
 The same acid is also produced spontaneously during the 
 putrefaction of a great many vegetable substances, particularly 
 of that of the woody fibre. (See Chap. VII, spontaneous de- 
 composition of vegetable substances). 
 
 B. VEGETABLE ACIDS, CAPABLE OF SUBLIMATION. 
 
 329. The most important acids belonging to this 
 class are the benzoic, succinic, and boletic adds, which are 
 found, already formed, in many plants, but may be obtain- 
 ed also by the combustion of a number of vegetable sub- 
 stances. 
 
 1. Benzole Acid. 
 
 ^ 330. Benzoic acid occurs in dragons' bloody Peru- 
 vian balsam, and a gum (found at Botany Bay) called 
 Benzoin (hence its name) ; also in a variety of volatile 
 and essential oils; in cloves, and in some of the liquids of 
 quadrupeds. It is now generally obtained by heating 
 benzoin with dilute sulphuric acid, or by melting it at a 
 gentle heat. It crystalizes in white, soft needles of the 
 appearance of mother of pearl, reddens blue vegetable col- 
 ors, melts at a gentle heat, like fat, and evaporates at its 
 melting point in form of a white smoke. It combines 
 
316 SUCCINIC, BOLETIC, AND ACETIC ACID. 
 
 with the mineral alkalies and oxides, and forms a kind of 
 salts called benzoates. 
 
 2. Succinic Acid. 
 
 331. This acid occurs, already formed, in amber, 
 and is obtained from it by slow distillation. It is also pro- 
 cured by boiling powdered amber in water. It forms white, 
 transparent crystals, melts at a gentle heat, and becomes 
 converted into white, sharp vapors, which condense into 
 flakes, and finally into long, crystaline needles. It com- 
 bines with the mineral and volatile alkalies (ammonia). 
 The salts which it forms are called succinates. 
 
 3. Boletic Acid. 
 
 33*2. This acid is obtained from the juice of a par- 
 ticular plant, called Boletus Pscudoignarius. It crys- 
 talizes in four-sided prisms. Its taste is similar to tartaric 
 acid. In fire it becomes converted into white, suffocating 
 vapors. 
 
 C. LLQUID VEGETABLE ACIDS (CAPABLE OF DISTILLA- 
 TION). 
 
 333. To this class belong acetic acid, from which 
 vinegar is obtained, Prussic acid, and cyanic acid. The 
 two last have already been described in mineral chemistry 
 ( 89, <j 92) ; because they can be produced by art from 
 the chemical combination of their elements. But they 
 occur also in vegetables, and seem, indeed, to be an in- 
 termediate link between mineral and vegetable formation. 
 
 It will appear from reviewing 89 92 that Prussic and 
 cyanic acids are ternary combinations of carbon, nitrogen and 
 oxygen, and on this account already exceptions to other inor- 
 ganic formations, which are generally products of two and 
 two elements. (Compare the remark, page 25'3). 
 
 1. Acetic Acid (Vinegar). 
 334. This acid occurs either in its simple form, or 
 
ACETIC ACID. 
 
 317 
 
 mixed with potash and lime in the juice of a great many 
 plants, particularly in the sap of trees, and in some min- 
 eral waters. It is also formed at the spontaneous de- 
 composition of vegetable substances, especially such as 
 contain more or less alcohol in grapes, fruits, &.c, (see 
 Chap. VII, acetous fermentation) and at the dry distil- 
 lation or imperfect combustion of plants. It is the princi- 
 pal ingredient of common vinegar, which consists chiefly 
 of acetic acid, mucilage, coloring matter and water. 
 
 Acetic acid is commonly prepared by mixing wine, cider, beer, 
 or dilute spirit of wine with vinegar, and exposing the mixture 
 in an open vessel (for several weeks) to a heat of about from 
 80 to 90 Fahrenheit. If vinegar be distilled to thickness, the 
 residue is almost pure acetic acid, mixed with a small quantity 
 of water. If distilled vinegar be exposed to severe cold, part 
 of its water freezes, and the remaining vinegar is much strong- 
 er than before. 
 
 Properties of acetic acid. Acetic acid in a pure state, 
 as radical vinegar, is colorless, possesses a well-known, 
 strong smell, a. very acid taste, and is capable of being en- 
 tirely volatilized. It boils a little above 212, and freezes 
 at about 27 below the freezing point of water. It acts 
 speedily on all oxidable metals, such as iron, lead, tin, 
 copper, &c, and combines with them, as well as with oth- 
 er mineral oxides, and forms with them a distinct class of 
 salts the acetates. The most remarkable among these 
 are the acetates of potash (arcanum tartari), of soda, ba- 
 ryta, magnesia, copper, and lead. The acetate of lead is 
 produced in great abundance at the manufacture of sugar 
 of lead. Most of the other acetates are used in medicine, 
 and for technical purposes. 
 
 Acetic acid combines also with sugar, gum, the essen 
 tial oils, alcohol and other organic substances. When, in 
 form of vapors, it is passed through a red-hot iron tube, it 
 is decomposed into carbonic acid and carbureted hydro- 
 gen gas, which proves that acetic acid differs in its com- 
 position from alcohol, only in the greater proportion of its 
 oxygen. 
 
 27* 
 
318 PRUSSIC AND CYANIC ACIDS. 
 
 2. Prussic Acid. 
 
 335. This volatile and most poisonous acid is found 
 in several plants, particularly in almonds, in the stones of 
 peaches, plumbs, cherries, &c, also in the leaves and bark 
 of trees, &,c ; but is generally obtained by the combus- 
 tion with potash of several animal substances ; for instance, 
 the blood, which contains its elements, carbon, nitrogen, 
 and oxygen. When Prussic acid is treated with blood, 
 alum, and vitriol of iron, it yields the celebrated Berlin 
 or Prussian blue, which is an extensive article of com- 
 merce. The other properties of Prussic acid have already 
 been described in Chapter II, 91 and 92. The same 
 holds of 
 
 3. Cyanic Acid, 
 
 which has been spoken of in Chap. II, 89. 
 
 REMARK. Besides the vegetable acids here described, there 
 are yet a number of others, which have not, however, been 
 sufficiently examined, and are not yet extensively used in the 
 arts ; on this account it may perhaps be well to omit them in 
 an elementary treatise. 
 
 IV. VEGETABLE SUBSTANCES OF AN UNDETERMINED 
 
 NATURE. 
 
 336. The vegetable substances belonging to this 
 class and their chemical composition are far from being 
 satisfactorily known. But few of them have been obtain- 
 ed in their simple forms, and there is hardly one among 
 them, the proportion of whose elements is accurately de- 
 termined. They are nevertheless of great importance to 
 the arts, with regard to which they may be divided into 
 three classes : coloring matters, vegetable extracts andfer- 
 mentous principles. 
 
 1. Coloring Matters. 
 
 337. Of these, a great number is contained in the 
 most heterogeneous plants, and it may, perhaps, be said 
 
COLORING MATTERS. 3J9 
 
 that not half of them are as yet sufficiently employed in 
 the arts. The following are the most remarkable : 
 
 1. The RED color of alizarine, lac-lake, cam-wood, saf- 
 floicer (carthamus seed), sanders (red) wood, amatto, and 
 dragons' blood. 
 
 2. The BLUE color of litmus, indigo, and woad. 
 
 3. The YELLOW color of Fernambucco-icood, zaffer, 
 saffron, dyer's weed (iceld), fustic, turmeric, gamboge, and 
 rhubarb. 
 
 4. The GREEN color of the black-thorn berry, of the 
 leaves of trees ; and 
 
 5. The FALLOW color of Venice-sumac and sanders. 
 Some of these dyeing stuffs are soluble in water or dilute 
 
 spirits of wine, and are called coloring extracts ; others, 
 on the contrary, are only entirely dissolved in alcohol, like 
 the red-color of safflower, of gamboge, &,c. These are 
 called resinous colors. They are all bleached by chlo- 
 rine and muriatic acid (indigo not excepted). Most of 
 them exhibit a different color when dissolved with the 
 alkalies, ammonia, potash, or soda ; the violet becomes 
 violet-green ; the yellow becomes brown, &/c. Concen- 
 trated acids destroy most of them, as we have seen in 
 treating of the different acids. When heated they burn 
 with a sour smoke, and leave, after combustion, a small 
 portion of ashes. 
 
 Some of the salts, when mixed with different solutions of 
 coloring matters, part with the oxides of which they are com- 
 posed, and leave them to unite with the vegetable substances, 
 the color of which is by this means, materially changed. The 
 salts most liable to this decomposition are alum, muriate (chlo- 
 ride) of tin, acetate of lead), and vitriol of iron. Hence their 
 use in dyeing. 
 
 338. Indigo belongs to the few coloring matters, 
 which are obtained from vegetables in a pure state. There 
 are various kinds of indigo, viz : red-indigo, green-indigo, 
 blue-indigo, &c. The elements of those which are belst 
 known are oxygen, hydrogen, carbon and nitrogen. In- 
 digo is extensively used in dyeing, on which account it is 
 a valuable article of commerce. 
 
320 VEGETABLE EXTRACTS LEES 
 
 2. Vegetable Extracts. 
 
 339. These were formerly divided into sweet, sour, 
 coloring, resinous, glutinous, narcotic, and bitter extracts, 
 most of them, however, have, of late, been found to belong 
 to other classes of vegetable matter ; wherefore those only 
 are, properly speaking, vegetable extracts, which are solu- 
 ble in water and dilute spirits of wine, incapable of crys- 
 talization, and a solution of which, when exposed to the at- 
 mosphere, precipitates in brown flakes. 
 
 The bitter taste which most of them possess, is more 
 or less variable ; but all agree in the following properties : 
 
 1. When recently extracted from the plant they are 
 brown, brittle, transparent, and specifically lighter than 
 water. 
 
 2. They absorb moisture from the atmosphere, and 
 leave, when shaken with water, a scum at the surface. 
 
 3. They are soluble in liquid potash ; but not in pure 
 alcohol, ether or the essential oils. 
 
 4. They become soft by heat, burn (at least, some of 
 them) and leave a small portion of ashes. 
 
 None of them have, as yet, been obtained in their 
 simple form. 
 
 3.- Fermentous Principles. 
 
 $ 340. To this class of bodies belong those vegetable 
 substances which, in combination with sugary bodies, pro- 
 duce the spontaneous process of fermentation (see Chap. 
 VII spontaneous decomposition of vegetables). They 
 occur generally in seeds and fruits, more seldom in stalks 
 and leaves of plants. They are neither soluble in water 
 nor alcohol ; but readily dissolved in diluted potash, and in 
 sulphuric or muriatic acid. When exposed to moisture 
 they emit a highly disagreeable smell, similar to putrefying 
 meat ; proving thereby that nitrogen enters into their 
 composition. They may be divided into lees (dregs), veg- 
 etable albumen, and gluten. 
 
 a. Lees (dregs). 
 341. Lees or dregs are the sediment deposited by 
 
VEGETABLE ALBUMEN. GLUTEN . 321 
 
 all fermentous liquors. They form a yellowish-grey, smeary 
 mass, which, when washed with water has a peculiar smell 
 and bitter taste. When perfectly dry, it forms a yellow- 
 ish-brown, brittle body, which is but sparingly soluble in 
 hot water and boiling alcohol. 
 
 b. Vegetable Albumen. 
 
 342. This is a substance more or less contained in 
 all vegetable juices, from which it may be extracted by 
 means of cold water, in a manner similar to starch (see 
 309). It contains a considerable quantity of nitrogen. 
 When boiled it expands in a sort of foam, like the white 
 of an egg (hence the name) ; and when dry forms a grey, 
 brittle mass, which becomes slightly decomposed when 
 boiled with alcohol. 
 
 c. Gfat&tt. 
 
 343. This substance is principally obtained from 
 wheat flour, which by the gradual addition of water is 
 formed into a soft, ductile paste. This is afterwards 
 washed with water, while the paste is worked between the 
 fingers, until the water flows off in a clear stream. By 
 this process the starch and vegetable albumen (see last 
 section) are carried off, and the pure gluten remains in the 
 hands. It is of a grey color, possessing almost as much 
 elasticity as elastic gum, and may be drawn out and will 
 contract again like this substance. It is insoluble in wa- 
 ter, adheres to all solid substances, and appears, when 
 dry, as a hard, brittle, greyish-brown body. When moist 
 it undergoes putrefaction, and emits a very offensive smell. 
 When, in a state of moisture, it is boiled in alcohol, it be- 
 comes decomposed into three distinct parts, viz : a yellow- 
 ish, glutinous mass which remains dissolved in the alcohol 
 a sort of mucilage which is precipitated and a third 
 substance which remains undissolved. 
 
 The precise proportions of the elements of gluten are not 
 yet ascertained ; but whatever its chemical composition 
 may be, it belongs certainly to the most important vegeta- 
 ble substances, and affords the principal nutriment con- 
 tained in plants. 
 
322 RECAPITULATION 
 
 RECAPITULATION. 
 
 Questions for Reviewing the most important Principles 
 contained in Chapter V. 
 
 A. QUESTIONS ON THE GENERAL REMARKS ON THE DIF- 
 
 FERENCE BETWEEN ORGANIC AND 
 
 INORGANIC BODIES. 
 
 [ 297.] Do the bodies in animated nature obey the 
 same laws to which they are subjected in dead matter ? 
 As what may every living body be considered ? Through 
 what two periods must all bodies pass t which are endow- 
 ed with life ? 
 
 [ 298.] In what consists principally the difference be- 
 tween organized and unorganized matter 1 
 
 Are the inorganic elements of plants and animals also per- 
 ishable ? What then is it that is destroyed by the death of the 
 animal or plant? In what is the life of the plant or animal 
 seated ? What must this directing agent be superior to ? 
 
 [ 299.] What are we in inorganic chemistry gener- 
 ally able to do ? Is this also possible with regard to plants 
 or animals? What do organic bodies even need for their 
 support ? 
 
 Give examples. 
 
 [ 300.] In what do the chemical processes of plants 
 and animals take place ? What are these vessels called ? 
 
 Do we know anything as regards the manner in which these 
 processes are carried on ? Do we know for certain whether 
 the different elements which we have discovered in plants and 
 animals are actually chemically combined with one another, 
 or whether they exist only in a state of mixture ? 
 
 [ 301.] W T here are the products of vegetables which 
 are used in domestic economy or in the arts seated ? What 
 processes are required for the collection of those products 
 which are diffused throughout the whole plant ? 
 
OF CHAPTER V. 
 
 [ 302.] What are the immediate ingredients of plants, 
 which are obtained by chemical analysis ? 
 
 [ 303.] By what means may the liquid and solid 
 parts of plants be again decomposed ? What are the ele- 
 ments resulting from their decomposition ? 
 
 Give examples. 
 
 [ 304.] How many different elements result from 
 the decomposition of the more remote ingredients of plants 
 into their ultimate principles ? Which elements are the 
 ultimate principles of plants ? 
 
 [ 305.] Into what four classes may all vegetable mat- 
 ter be divided ? 
 
 QUESTIONS ON THE UNSALIFIA.BLE VEGETABLE SUBSTAN- 
 CES. 
 
 [ 306 ] Into what two classes may all unsalifiable 
 vegetable substances be again divided ? What vegetable 
 substances are called neutral? What substances are 
 called watery ? 
 
 [ 307.] Which are the most remarkable neutral un- 
 salifiable substances from the vegetable kingdom ? 
 
 [ 308.] How is woody fibre obtained ? What are its 
 properties ? 
 
 [ 309.] How is starch obtained ? What are its 
 properties ? 
 
 [ 310.] Where does mucilage or gum occur ? When 
 is it termed mucilage ? When, gum 1 What are the 
 properties of these substances ? What are the peculiar 
 properties of gum 1 Into what does it become converted 
 by the action of nitric acid ? What does it yield when 
 distilled in a retort 1 
 
 [ 311.] From what plants is sugar obtained? By 
 what process is the raw sugar of commerce obtained from 
 the sugar-cane ? What is the remaining liquid called af- 
 
324 RECAPITULATION 
 
 ter the sugar shoots in regular crystals ? By what means 
 is the raw sugar refined, and made loaf sugar ? How is 
 candied sugar obtained 1 Into what does sugar become 
 converted when distilled with nitric acid ? 
 
 [^ 312.] Where do watery unsalifiable substances oc- 
 cur ? What watery, unsalifiable vegetable substances oc- 
 cur in nature ? Which are products of art ? What prop- 
 erty do they all possess in a high degree ? 
 
 [ 313.] By what properties are the volatile or essential 
 oils distinguished 1 From what vegetable organs are they 
 obtained 1 What properties do they generally possess ? 
 For what purposes are they used ? 
 
 To what class of oils does camphor belong 1 Into what 
 does it become converted by nitric acid 1 What does it 
 form in combination with the alkalies and oxides ? 
 
 [ 314.] By what means are the fats or fixed oils ob- 
 tained ? What are their properties 1 What do they form 
 when combined with the alkalies ? For what purposes 
 are they especially calculated ? 
 
 What may take place when the fixed oils are mixed with 
 lamp-black, charcoal, cotton, flax, or wool ? What ought this 
 to teach us ? 
 
 [ 315.] To what substances has the name of resins 
 been applied ? What substances belong to this class of 
 bodies ? 
 
 What is the color and property of most resins? For 
 what purposes are they used 1 
 
 How is India rubber or gum elastic obtained ? What 
 substance is it supposed to contain in considerable quanti- 
 ty 1 What invaluable property does it possess ? For what 
 purposes is it, on this account, used ? 
 
 [ 316.] From what substances is wax obtained? 
 What are its properties ? Of what elements is it composed ? 
 How many per cent of carbon and hydrogen does it con- 
 tain ? What does this account for ? 
 
 [ 317.] What sort of product is alcohol ? Where is 
 it contained ? 
 
OF CHAPTER V. 325 
 
 What are the properties of pure alcohol ? How does it 
 act upon animal and vegetable substances 1 By what 
 means may it be decomposed ? What does it yield when 
 decomposed ? 
 
 What is the difference in the chemical composition between 
 woody fibre, starch, sugar, and alcohol ? What, therefore, 
 must be founded in their different proportions ? 
 
 [ 318.] Into what does alcohol become converted 
 when distilled with the different acids? What is the yel- 
 lowish liquid called which remains? What does oil of 
 wine form when again combined with the acids ? What 
 properties do both products possess ? How are the differ- 
 ent kinds of ether distinguished from one another ? Give 
 examples. What kind of ether is extensively used in 
 medicine ? By what means is it obtained ? 
 
 QUESTIONS ON THE SALIFIABLE VEGETABLE BASES. 
 
 [ 319.] How many different bodies belong to this 
 class? What are their properties? What do they form 
 with the acids ? What are their ultimate principles ? 
 How are the salts denominated which these substances 
 form with the various acids ? 
 
 QUESTIONS ON THE VEGETABLE ACIDS. 
 
 [$} 320.] By what means are the vegetable acids dis- 
 tinguished from the neutral or unsalifiable vegetable sub- 
 stances ? In what state do they occur ? 
 
 A. Fixed Vegetable Acids. 
 
 [ 321.] By what properties are the fixed vegetable 
 acids generally distinguished? What are the most re- 
 markable vegetable acids ? 
 
 [ 322.1 In what plants does tartaricacid occur in i^s 
 simple form ? From what other substaroe may it yet be 
 obtained ? In what way ? What sort of salt does tartaric 
 acid form when united with the alkalies ? How is this 
 salt obtained? 
 
 28 
 
RECAPITULATION 
 
 What sort of substance is bi-tartrate of potash, or 
 tartar ? 
 
 [ 323.] Where does citric acid occur ? How may it 
 be produced by art? In what way is it commonly obtain- 
 ed? Into what substance does citric acid become con- 
 verted when slowly heated with alcohol ? W T hat are the 
 salts called which citric acid forms in combination with 
 the different salifiable bases ? 
 
 [ 324.] In what vegetable substances does malic acid 
 occur ? From what kind of berries is it commonly ex- 
 tracted ? What are its properties? What are the salts 
 called which it forms in combination with the salifiable 
 bases ? 
 
 [ 325.] What are the properties of oxalic acid ? 
 What class of salts does it form with the different salifiable 
 bases ? What are the most remarkable salts belonging 
 to that class ? 
 
 [ 326.] In what substances is gallic acid contained? 
 In what way is it chiefly obtained ? 
 
 What are the principal properties of gallic acid ? What 
 sort of precipitate is obtained from a saturation of gallic 
 acid, with carbonate of potash, or muriate of tin ? Of 
 what is gallic acid a principal ingredient ? 
 
 [ 327.] How is vegetable jelly obtained ? How may 
 it be purified ? What shape does it exhibit, when dry ? 
 What kind of taste has it in a slate of moisture ? With 
 what substances does it combine ? 
 
 [ 328.] From what substances is bitumous acid pro- 
 duced ? What properties does this acid possess, when 
 perfectly dry ? Into what substances does it become de- 
 composed by dry distillation ? 
 
 During what other process is bitumous acid produced ? 
 
 [ 329.] Which are the most important acids belong- 
 ing to the class of vegetable acids, capable of sublimation ? 
 Where are these acids found ? How may they be ob- 
 tained ? 
 
OF CHAPTER V 
 
 327 
 
 330.] Where does benzole acid occur ? In what 
 way s it generally obtained ? What are its properties 1 
 
 What class of salts does it form 
 mineral alkalies and oxides? 
 
 in combination with the 
 
 [ 331.] Where does succinic acid occur ? By what 
 means may it be produced ? What are its properties 1 
 What class of salts does it form with the mineral and vol- 
 atile alkalies? 
 
 [ 332.] From what substance is boletic acid obtain- 
 ed ? What are its properties ? 
 
 [ 333.] What acids belong to the liquid vegetable 
 acids ? Where do Prussic and cyanic acid occur 1 What 
 do these two acids seem to be ? Of what elements are 
 they compounded ? 
 
 [ 334.] Where does acetic acid occur ? By what 
 other processes is it formed ? Of what substance does 
 acetic acid form the principal ingredient? What is the 
 composition of vinegar ? 
 
 How is vinegar prepared ? What sort of residue is obtain- 
 ed when vinegar is distilled to thickness ? By what means 
 may vinegar be rectified (made stronger) ? 
 
 What are the principal properties of acetic acid ? What 
 class of salts does it form with the mineral oxides ? Which 
 are the most remarkable of these salts ? 
 
 With what other organic substances does acetic acid 
 yet combine ? In what consists the difference between 
 the chemical composition of vinegar and alcohol ? 
 
 [ 335.] From what substances may Prussic acid be 
 obtained? What does Prussic acid yield when treated 
 with blood, alum, and vitriol of iron ? 
 
 QUESTIONS ON VEGETABLE SUBSTANCES OF AN INDETER- 
 MINED NATURE. 
 
 [ 336.] Into how many classes may all vegetable sub- 
 stances of an indeterrnined nature be divided? What are 
 the three classes ? 
 
328 RECAPITULATION. 
 
 [ 337.] Which are the most remarkable coloring mat- 
 ters found in plants ? 
 
 What are those dyeing stuffs called which are soluble 
 in water, or dilute spirits of wine ? What colors are only 
 entirely dissolved in alcohol ? How are they all acted up- 
 on by chlorine and muriatic acid ? What do all of them 
 leave after combustion ? 
 
 What becomes of some of the salts when mixed with differ- 
 ent solutions of coloring matter ? Which salts are most liable 
 to this decomposition ? 
 
 [ 338.] In what state is indigo obtained from vege- 
 tables ? What are the elements of the different kinds 
 of indigo? 
 
 [ 339.] How were the different vegetable extracts 
 formerly divided ? What substances are properly called 
 vegetable extracts ? How do most of them taste 1 
 
 By what properties are they all more or less distinguish- 
 ed ? Has any of them as yet been obtained in its simple 
 form? 
 
 [ 340.] What vegetable substances are called fer- 
 mentous principles? Where do they occur? What are 
 their properties ? Into how many different substances may 
 they be divided ? 
 
 [ 341.] What are lees or dregs ? What sort of mass 
 do they form ? What are the properties of this mass ? 
 
 [ 342.] What sort of substance is vegetable albumen? 
 In what way may it be obtained ? What does it form when 
 heated or boiled ? What properties does it possess when 
 perfectly dry ? 
 
 [ 343.] How is gluten obtained ? What are its prop- 
 erties ? Into what three distinct substances does it be- 
 come decomposed, when, in a state of moisture, it is boiled 
 in alcohol ? 
 
 Why does gluten belong to the most important vegeta- 
 ble substances ? 
 
ANIMAL CHEMISTRY. 
 
 CHAPTER VI. 
 
 ANIMAL CHEMISTRY.* 
 
 344. Ingredients of the Animal Body. The ani- 
 mal body consists, like the plant, of immediate, more re- 
 mote, and ultimate chemical ingredients. The immediate 
 ingredients, which are discovered by the chemical inves- 
 tigation of animal substances, are 
 
 1 . Gaseous ; viz : Carbureted hydrogen gas, Carbonic 
 acid gas, Nitrogen, Oxygen, &c. 
 
 2. Liquid; like the Gastric juice of the stomach, Sa- 
 liva, mucilage, bile, chyle, blood, milk^&LQ. 
 
 3. Soft, and easily melting. To these belong the greasy 
 substance in the joints, the marrow, the fat, the humors of 
 the ear and eyes, &c. 
 
 4. Soft and Elastic ; like the muscles, the flesh, liga- 
 ments, tendons, the membranes, cartilage, hair, scales, fea- 
 thers, wool, &c. 
 
 5. Hard; the bones, horns, and hoofs of animals, the 
 elates, and nails, and the coverings of insects. 
 
 345. These ingredients of the animal body, may, 
 
 * We shall not dwell, here, upon the principal difference between 
 plants and animals, which undoubtedly consists in sensation and lo- 
 comotion of the latter. This is a more proper subject for Natural 
 History and Physiology. Chemistry treats only of the combination 
 and analysis of substances, as far as the elements of matter are con- 
 cerned, and with regard to these, the remarks made on the compo- 
 sition of vegetables, ( 297 301), apply equally to that of an- 
 imals. 
 
 28* 
 
330 ANIMAL CHEMISTRY. 
 
 like those of the plants, be divided into combustible and 
 incombustible substances. The combustible ones are again, 
 
 1. Neutral ; in which the hydrogen is to oxygen in the 
 same proportion as in water, (as 1 to 8), like the sugar of 
 milk. 
 
 2. Watery ; in which the hydrogen is to the oxygen in 
 a larger proportion than in water, (in a larger proportion 
 than 1 to 8), like the oils and fats. 
 
 3. Acetous ; in which the hydrogen is to the oxygen in 
 a less proportion than is necessary to form water, (in a less 
 proportion than I to 8). To this class belong the animal 
 acids. 
 
 4. Undetermined; like fibrin, glutin, cheese, &c. 
 The incombustible animal substances, which remain as 
 
 ashes at the combustion of those we have just enumerated, 
 are either oxides or salts. The principal oxides obtained 
 by the combustion of animal matters, are soda, silicons 
 earth, oxide of iron, and of manganese. The salts produ- 
 ced in the same manner are carbonate of lime, and potash, 
 muriate of soda, (chloride of potassium), sulphate of lime, 
 and phosphate of lime and magnesia. 
 
 346. The ultimate principles or elements of the 
 animal body are the same as those of the plants ; viz ; hy- 
 drogen, oxygen, carbon, and nitrogen; to which may be 
 added a small proportion of sulphur, phosphorus, magne- 
 sium, and iron ; but the proportion, in which these ele- 
 ments are combined, are essentially different from those in 
 which they are compounded in vegetables. That nitrogen 
 enters much more into the composition of animal sub- 
 stances than it does in that of vegetables, is sufficiently 
 evident from the highly offensive smell which accompanies 
 their spontaneous decomposition, owing to the ammonia, (a 
 compound of nitrogen), and sulphureted hydrogen, which 
 are then given off in great quantities. 
 
 Among the various parts of which the animal body is com- 
 posed, those enumerated in 344 and 345 are by far t' c 
 most interesting ; we shall proceed now to describe those 
 among them, a knowledge of which is indispensable to a proper 
 understanding of our own physical organization. 
 
ANIMAL JELLY. -ALBUMEN. 331 
 
 1. Animal Jelly, (Glue). 
 
 $ 347. Animal Jelly, or glue, (or at least, a substance 
 which by boiling with water becomes changed into jelly),* 
 composes the cellular membranes, the skin, ligaments, and 
 tendons, as well as the cartilage, and the cartilaginous 
 parts of the bones of most animals. It is obtained chiefly 
 by boiling these substances, (more especially the skins and 
 bones) for a considerable time, after having previously 
 washed them with cold water. It possesses generally a 
 pale yellowish color, and is semi-transparent and elastic ; 
 but when dry, it is solid, brittle, and of a lamellar texture. 
 It is specifically heavier than water, without taste or smell, 
 and does in no way effect vegetable colors. A solution of 
 animal glue, or the gelatinous substance it forms with wa- 
 ter, soon undergoes spontaneous decomposition, accom- 
 panied by a fetid smell, produced by the ammonia which 
 is given off during this process. 
 
 The connecting power of glue is weakened by boiling ; but 
 its solubility is thereby increased. When submitted to dry 
 distillation, it is decomposed into a highly inflammable gas, car- 
 bonate of ammonia, a brown watery liquid, (spiritus cornu 
 cervi), a brown sort of tar, and a quantity of animal charcoal, 
 which, however, is less combustible than vegetable charcoal, 
 on account of the nitrogen which it contains. 
 
 Gelatine (animal glue mixed with water) is also soluble in 
 the acids, and in solutions of pure alkalies. It combines with 
 muriatic and several other dilute acids, and with a variety of 
 mineral bases and salts. 
 
 2. Albumen. 
 
 348. This substance occurs in the eggs of birds, 
 lizards, fishes, and insects ; in the chyle, the blood, and 
 in several secretions of the animal body. Of its occur- 
 rency in the vegetable kingdom we have already spoken 
 n the preceding chapter, ( 342). The white of eggs 
 contains much pure albumen, mixed, however, with acon- 
 
 * Many distinguished philosophers deny the existence of already 
 formed jelly in the animal body ; but consider it as a product of a 
 gluey substance boiled with water. 
 
332 BLOOD. 
 
 siderable portion of water. By evaporating this, albumen 
 is obtained in a solid state. 
 
 Properties. When albumen is exposed to a temperature 
 of about 174 Fahrenheit, it becomes converted into a 
 white, solid, somewhat elastic mass ; which when perfectly 
 dry, changes into yellow, becomes hard and brittle, is in- 
 soluble in water, and resists putrefaction for a considerable 
 length of time ; whereas, in a coagulated state, it speedily 
 undergoes spontaneous decomposition. A solution of al- 
 bumen in water coagulates at a boiling heat, and so much 
 is this a characteristic of albumen, that even a solution of 
 one single part of it in one thousand parts of water, be- 
 comes opaque at a temperature of 212 Fahrenheit. When 
 burned in an open fire, it emits a smell like burnt feathers, 
 and leaves charcoal. From a solution in water, it may be 
 precipitated by nitric, sulphuric, and muriatic acid. It 
 combines with the mineral bases and salts, and with lime 
 forms a perfectly solid mass. By dry distillation it is de- 
 composed into its elements, hydrogen, carbonic acid gas, 
 prussic acid, water, carbonate of ammonia, nitrogen, and 
 carbon. 
 
 3. Blood. 
 
 349. This liquid, into which all nutriment is con- 
 verted, and which by its circulation renews constantly the 
 whole organization of the body, consists principally of three 
 parts, viz : 1, a certain fibrous substance termed fibrin; 
 2d, of albumen, (which is the cause of its coagulation by 
 heat and the acids) ; 3d, of a small variable proportion of 
 mineral salts, (chloride of sodium, potassium, phosphate of 
 lime, &c.). These substances have for each other but 
 little affinity ; for in a very short time after blood has been 
 drawn from the vein, it coagulates, that is, becomes sepa- 
 rated into two very distinct parts, viz. into a yellowish-green 
 liquid, which exudes from below the surface, the scrum, 
 and a remaining solid substance, called the cruor. 
 
 The cerum consists of a solution of albumen, gelatine, 
 and salt of sodium, potassium, and magnesia. The cruor 
 can, by washing with water, again be separated \niojibrin 
 
BLOOD. MILK. 333 
 
 and coloring matter. The latter ingredient consists of 
 nearly the same elements as albumen, (see the preceding 
 section), with an almost imperceptible addition of oxide of 
 iron.* 
 
 Chemical Changes in the Nature of Blood, occasioned by 
 Respiration. 
 
 350. The process of respiration consists, as is gen- 
 erally known, in two distinct operations. By the first, 
 which is termed inspiration, a certain portion of atmosphe- 
 ric air is taken into the lungs, which after coming in con- 
 tact with the blood, and suffering certain chemical changes, 
 is by the second again expelled. The changes which 
 atmospheric air undergoes by the process of respiration, 
 are the following : 
 
 1. The whole volume of air is considerably diminished. 
 
 2. The quantity of oxygen is reduced. 
 
 3. It receives an addition of vapors of water, and, in 
 men, also of nitrogen, together with a considerable portion 
 of carbonic acid gas. 
 
 The changes produced in the blood by the same cause, 
 consists principally, 
 
 1. In an absorption of oxygen,"^ 
 
 2. In a diminution of carbonic acid and water, and 
 
 3. In a subsequently lighter color, owing to the dimi- 
 nution of carbon. 
 
 An account of the absorption of oxygen gas (1) the process 
 of respiration is generally called the oxidation of the blood. 
 Some philosophers, however, call it the de carbonization of the 
 blood, because a great quantity of carbon is expelled. How far 
 the process of respiration is necessary to animal life, and what 
 important end in the constitution of man and animals is thereby 
 answered, is a subject for Physiology. 
 
 4. Of the Milk. 
 351. This well known white liquid, which exists in 
 
 * See Gmehlin's Chemistry, Heidelberg, 1830. 
 t Some Philosophers pretend also of nitrogen. 
 
334 BUTTER. CHEESE. 
 
 the breast of female quadrupeds, and in all other animals 
 which bring forth living young ones, is composed of the 
 following ingredients : 
 
 1. Water, (by far in the greatest proportion). 
 
 2. A small portion of pure acetic acid. 
 
 3. A fat substance, called butter. 
 
 4. Animal albumen. 
 
 5. Mucilage. 
 
 6. Sugar of milk ; and 
 
 7. A small proportion of salts of potash, lime, and mag- 
 nesia. 
 
 These substances appear to be partly in a state of so- 
 lution, and partly only suspended in the liquid. When 
 milk is boiled, a portion of its animal albumen collects at 
 its surface in form of a pellicle, (small skin), which as soon 
 as it is removed, is replaced by another. If it falls to 
 the bottom, it becomes burnt, and imparts to the milk a 
 peculiar, disagreeable taste. It is probable that heated milk 
 would entirely coagulate, like albumen, if this latter sub- 
 stance were not diffused through a great portion of water. 
 
 5. Butter. 
 
 352. If milk is suffered to stand, even excluded 
 from the atmosphere, a spontaneous decomposition takes 
 place an oily unctuous substance rises to the top, which 
 is called cream. This is by agitation (churning) again 
 separated into a substance called butter, and a thin fluid 
 resembling milk deprived of its cream. Butter is a val- 
 uable article of domestic economy ; possesses generally a 
 yellow color, a peculiar agreeable taste, and is of a soft 
 consistency. When melted, which may be effected at a 
 temperature of 98 Fahrenheit, it becomes transparent ; 
 but its taste is rendered less agreeable. In this state, or 
 salted, it may be kept much longer without becoming ran- 
 cid, and is capable of transportation by sea. 
 
 6. Cheese. 
 
 353. When milk is allowed to stand until, by a sort 
 
SUGAR OF MILK. ANIMAL MUCUS. 335 
 
 of acetous fermentation (see Chap. VII.) it becomes sour, it 
 coagulates, and forms two distinct parts ; viz. the curd, 
 which is a solid substance, and a liquid called whey. The 
 curd of milk, pressed, salted, and dried, composes cheese. 
 The whey, a thin, transparent fluid, contains still a portion 
 of curd and butter, and is used in Switzerland for the pre- 
 paration of certain kinds of cheese. 
 
 7. Sitgar of Milk. 
 
 354. The whey of milk, when separated from butter 
 and curd, and evaporated at a gentle heat, yields a sub- 
 stance called sugar of milk. This is a solid mass, which 
 is readily dissolved in water, and may be clarified with the 
 white of eggs, and again evaporated. Upon cooling, it 
 forms regular crystals of a sweetish taste, which are insol- 
 uble in alcohol. 
 
 Remark. There is considerable difference between the 
 milk of different animals. Human milk is sweeter than that of 
 cows, but yields no butter. Goats 1 milk is thick and fat, and 
 abounds in curd. Its butter is less consistent than that of 
 cows' milk; but it contains more sugar of milk. The milk of 
 sheep resembles that of cows, and yields the greatest quantity 
 of butter. Mare's milk yields hardly any butter, or cream. 
 Jlsses' milk is the most watery of all, and contains the least 
 quantity of curd and butter. 
 
 8. Animal Mucus. 
 
 355. This substance is obtained by washing mucus 
 secretions with cold water, and drying the parts which re- 
 main undissolved. It is transparent and brittle, and con- 
 sists principally of carbonate of ammonia, and animal oil. 
 Together with water, it forms the principal ingredient of 
 the mucus of the nose, tears, wind-pipe, saliva, and bile, 
 and the intestines. 
 
 9. Animal Oils and Fats. 
 
 356. To this class of animal substances we reckon 
 chiefly butter, tallow, lard, wax, and spermaceti. 
 
 Butter and wax have already been described, (in 352, 
 
ANIMAL, ACIDS. OLIFIC ACID. 
 
 316). Fat is extracted from muscular and membranous 
 substances, by exposition to a gentle heat. Fat thus pu- 
 rified is called lard when soft, and tallow when of a hard 
 consistency. It has an insipid taste, and when perfectly 
 pure is destitute of smell. It is insoluble in water, or alco- 
 hol, but united with potash or soda, forms soap, (see 
 Chap. Ill, 150). By long keeping it becomes rancid, 
 which is probably owing to its combination with oxygen. 
 The fat of whales is obtained in a liquid state as an oil. 
 From its great value in artificial illumination, it is an ex- 
 tensive article of commerce. 
 
 Spermaceti (sperm-oil) is chiefly obtained from the fat 
 of the white whale. It crystalizes from a solution in hot 
 alcohol in white shining leaves, or in a radiant mass. It 
 melts at 112 Fahrenheit, is inodorous, and has no action 
 on vegetable colors. It is extensively used for the manufac- 
 ture of candles. 
 
 10. Animal Acids. 
 
 357. The human and animal body contains or yields 
 a number of acids, which occur in the mineral and vege- 
 table kingdoms. To these belong the phosphoric, muri- 
 atic, sulphuric, carbonic, acetic, benzoic, and malic acidsj 
 all of which have already been described in the preceding 
 sections; but besides these, a number of others, which are 
 more or less peculiar to animal formation. The most im- 
 portantof these are \heolific, lactic, mucous, zndformic acid. 
 
 a. Olific Acid. 
 
 ^ 353 This acid is formed in the bile of men, bul- 
 locks, swine, and bears; also in old tallow and cheese. 
 It crystalizes in white needles, a little before the freezing 
 point of water, to a colorless or yellowish oil, (hence its 
 name), and evaporates under the recipient of an air pump, 
 without decomposition. It is soluble in water, has a faint 
 rancid taste and smell, and combines with the mineral 
 acids and bases. 
 
LACTIC, MUCOUS, AND FORMIC ACID. 337 
 
 b. Lactic Acid* 
 
 359. Lactic acid is found in its simple form, or united 
 with ammonia, potash and soda, in almost all animal parts 
 and liquids; in the blood, in the milk, muscles, &,c, (see 
 Chap. VII). It is also produced by the acetous fermen- 
 tation of a variety of vegetable substances ; or may be ob- 
 tained from sour milk, by evaporating it to about of its 
 volume, and filtering the residue. 
 
 Properties. It is a yellowish-brown syrup, incapable 
 of crystalization, which has a very sour taste, and deli- 
 quesces at the atmosphere. With the different mineral 
 alkalies it forms a kind of salt, called lactates. These 
 salts are soluble in water, (some of them also in alcohol), 
 and deliquesce in contact with air. 
 
 d. Mucous Acid. ( Saccho-Iactic Acid.) 
 
 360. Mucous acid is the product of nitric acid dis- 
 tilled with sugar of milk, or vegetable gum. It is a white, 
 sandy powder, which has little smell or taste, and reddens 
 litmus paper. It is soluble in cold, but much better in 
 warm water. When heated, it melts with a brown color, 
 and becomes partly decomposed into carbureted hydro- 
 gen gas, carbonic acid, acetic acid, and a sort of charcoal 
 of a metallic lustre. In a red-hot crucible it burns like 
 oil. With the mineral bases it combines to a kind of salts, 
 which are called saccho-lactales. 
 
 e. Formic Acid. 
 
 361.. The acidity of ants is taken advantage of, by 
 distilling them with water, by which means a peculiar acid 
 is obtained, which has received the name of formic acid, 
 (from a peculiar kind of ants called formica rufa). 
 
 Properties. Concentrated formic acid does not congeal 
 at any degree of artificial cold, although it is specifi- 
 cally heavier than water. It has a peculiar pricking, sour 
 
 * The two celebrated chemists, Fourcroi and Vauquelin, first dis- 
 covered this acid in the amnios of cows ; hence its name. 
 
 29 
 
SALIVA. GASTRIC JUICE BILE. 
 
 taste, may be mixed with water in all proportions, and 
 combines with the mineral alkalies to a kind of salts, 
 called formiates. 
 
 11. Of the Different Liquids employed in the Process of 
 Digestion. 
 
 362. The principal liquids and secretions which are 
 subservient to the process of digestion, are the saliva, the 
 gastric juice, and the bile. 
 
 a. Saliva. 
 
 363. This is a liquid secreted by certain glands, and 
 brought into the mouth to be mixed with the food during 
 mastication. It is transparent, gradually deposing its mu- 
 cous, inodorous, and nearly of the same specific gravity as 
 water. The saliva of men produces generally a weak, al- 
 kaline effect on vegetable colors, (reddens litmus paper). 
 During some diseases the saliva is sour, and forms with 
 nitric acid a transparent pellicle. It is principally com- 
 posed of water, mucous, albumen, chloride of potassium, 
 and phosphate of lime, soda, and ammonia. 
 
 b. Gastric Juice. 
 
 364. This liquid issues from the inner coats of the 
 stomach, and serves in the process of digestion, as a 
 most powerful solvent. It contains, besides several animal 
 substances, such as mucous, albumen, saliva, &c, muriatic 
 and acetic acid, together with chloride of potassium, and 
 sodium. The gastric juice, thrown up by vomiting, is 
 very much similar to saliva ; and it is therefore the opinion 
 of some celebrated physiologists, that the true gastric juice 
 is only a secretion in the stomach, through the irritation 
 produced by the food. Its solvent power is so great, that 
 after death the stomach itself is corroded by it. 
 
 c. Bile. 
 365. The bile of a healthy man has generally a 
 
CHYLE. 339 
 
 greenish-brown color, a bitter, nauseous taste, and is sel- 
 dom very clear or transparent, because a yellow, insoluble, 
 mucous substance 'is suspended in it. It is decomposed 
 by all the acids, whereby a large proportion of albumen 
 and resin is deposited. 
 
 Human bile consists principally, 
 
 1. Of a very bitter resin, which is the yellow substance 
 suspended in it, to which we have just alluded. 
 
 2. Of albumen. 
 
 3. Of soda, through whose agency the yellow resin is 
 kept in a liquid state. 
 
 4. Of mineral salts, phosphate and sulphate of soda, 
 chloride of sodium, and oxide of iron ; and 
 
 5. Of a large proportion (about 91 per cent) of water. 
 
 In sick persons the resinous substance suffers consider- 
 able diminution, which gives the bile nearly the same 
 appearance as albumen. 
 
 The bile of oxen, calves, sheep, dogs and cats consists of 
 resin, a sweet, sugary substance ; a peculiar yellow body, 
 composed of raucous and brown coloring matter, pure soda, 
 phosphate and sulphate of soda, chloride of sodium, phosphate 
 of lime, and even traces of phosphate of iron. 
 
 12. Of the Chyle. 
 
 366. By the digestion of food in the stomach, a white 
 juice is formed, which is afterwards yielded, and converted 
 into blood, through which the whole body receives its nu- 
 triment. The chyle of amimals, 4 or 5 hours after 
 taking food, possesses a perfectly white color, is, on ac- 
 count of its fat, more or less opaque, and has a saltish, 
 sometimes sweetish taste. It is specifically heavier than 
 water ; but lighter than blood. (If a person be bled 4 or 
 5 hours after taking food, a small portion of chyle will 
 float on top of the coagulated blood). It produces a weak 
 alkaline effect on the color of violets, which is changed 
 into green (see Intro, page 38). In about ten minutes 
 after being taken from the Thoracic duct, it becomes of 
 the consistency of jelly, and in course of 24 hours separates 
 into two parts, viz : into a solid coagulum, and a serous, 
 
340 BRAIN AND NERVES. 
 
 colorless liquid, similar to that obtained by the spontane- 
 ous decomposition of blood ( 349). The coagulum has 
 a strong resemblance to cheese, while the serous part, 
 dissolved in water, has a sweet taste, somewhat like milk, 
 to which the whole substance of the chyle is more or less 
 analogous. 
 
 Dry chyle, when burnt, yields 32 per cent of ashes, 
 consisting of carbonate of soda, chloride of potassium, a 
 little potash, and phosphate of lime. 
 
 13. Substance of the Brain and Nerves. 
 
 367. The brain of men and quadrupeds consists of 
 a soft, medullary substance, which undergoes spontaneous 
 decomposition when exposed to the air, and gives off a pe- 
 culiar acid before it undergoes putrefaction. It consists, 
 
 1st. Of a brownish-red, liquid fat, which, by its combus- 
 tion, yields phosphoric acid. 
 
 2d. Of a more solid lamellar fat (wax), peculiar to the 
 brain. 
 
 3d. Of phosphorus contained in these fats. 
 
 4th. Of an animal extract called osmazome. 
 
 5th. Of animal albumen. 
 
 6th. Of water, and 
 
 7th. Of a number of mineral salts, chloride of sodium, 
 phosphate of potash, of lime, of magnesia. 
 
 Nerves. The nerves of men contain less liquid, than 
 the brain, but more lamellar fat (wax of the brain), togeth- 
 er with a much larger portion of albumen. 
 
 The brain of a calf, or of an ox is of a greyish color ; its 
 fat is more greasy than crystaline, and it contains, besides 
 the substances enumerated in the human brain, a consid- 
 erable quantity of phosphate of ammonia with traces of 
 iron.* 
 
 * The analysis of a peculiar substance found in the brain of an id- 
 iot yielded 6 percent white tallow, half coagulated albumen, and a 
 peculiar cartilaginous matter, which was insoluble in water. See 
 Gmehlen's Chemistry, Vol. III. 
 
FIBRIN. BONES, TEETH, AND CARTILAGE. 341 
 
 14. Fibrin (Animal Gluten). 
 
 308. This substance forms the principal ingredient 
 of the muscular and fleshy parts of animals. It may be 
 procured in its simple form in two different ways. 
 
 1st. By washing meat or flesh cut up into small pieces 
 with cold, and afterwards with warm water; and 
 
 2d. By frequent ablutions of the coagulum of blood on 
 a linen strainer, until nothing but a white, fibrous matter 
 remains. 
 
 Properties. Tn a state of moisture it is a semi-transpa- 
 rent, elastic substance ; but when dry it is a brown, trans- 
 parent, brittle mass, which is insoluble in cold water ; but 
 gives to boiling water a milky color. It is specifically 
 heavier than water, and possesses neither taste nor smell. 
 It consists principally of carbon, oxygen, nitrogen, and 
 only a small proportion of hydrogen gas. 
 
 15. Of the Bones, Teeth, and Cartilage. 
 
 369. The bones and teeth of animals are composed 
 partly of earthy salts, which give them solidity and hard- 
 ness, and partly of animal matter, which serves for the 
 purpose of cement, and keeps the earthy ingredients in a 
 state of union.* 
 
 All bones contain a portion of cartilaginous gelatine ; 
 but the harder they are the less they possess of this 
 substance. When bones are boiled for a considerable 
 time in water, the cartilaginous matter is extracted from 
 them in form of animal glue. Cold muriatic acid dissolves 
 even their salts, and leaves them in a state of soft transpa- 
 rency, preserving still their natural shape and figure. 
 
 This state seems to be the first stage of organized bones, and 
 it is well known that the bones of infants and children partake 
 more or less of this nature, until by the growth of the individ- 
 ual they become gradually harder, and finally obtain that firm- 
 ness which they have in adults. 
 
 Bones are entirely dissolved in hot muriatic acid ; from 
 which, by adding ammonia, a precipitate may be formed, 
 
 * Henry's Chemistry, Vol. II, page 366. 
 29* 
 
342 MARROW. MUSCLES, MEMBRANES, &c. 
 
 consisting of a great proportion of animal glue, and phos- 
 phate of lime. By dry distillation they yield the same 
 product as animal jelly ; but leave a peculiar kind of char- 
 coal (bony charcoal) consisting of a mixture of animal coal, 
 and salts of magnesia and lime. 
 
 370. The teeth and the enamel with which they are 
 covered agree, in the main point, with the construction of 
 the bones ; but they contain, besides, as a basis, a pecu- 
 liar animal substance, of which the enamel seems to be 
 destitute. 
 
 According to the experiments made by the celebrated Dr 
 Antenrieth of the university of Tubingen, the bones of chil- 
 dren contain about 2 per cent of benzoic acid (see 339). Upon 
 growing, this acid is expelled ; but occurs again (about 1 per 
 cent), in old men, and is sometimes the cause of obstinate dis- 
 eases. 
 
 Cartilage, when boiled for some time in water, becomes 
 entirely dissolved, the product being animal glue or jelly. 
 
 16. On the Marrow. 
 
 $ 371. This substance is lodged in the hollow parts of 
 the long bones ; and consists chiefly of membranes, fat, 
 and red serum. The oily substance contained in most hard 
 and solid parts of the bones (Dipple's oil), consists merely 
 of fat and serum. It was formerly used in medicine. 
 
 17. Of the Muscles, Membranes, Ligaments and Tendons. 
 
 372. It is highly probable that muscular flesh con- 
 sists merely of fibrin, mixed, however with fat, blood, 
 mucous, and nerves. When washed with cold water it 
 yields albumen, saliva, osmazom and salts. When boiled 
 in water, it yields glue or fat, the residue being nearly 
 all fibrin, which, when burnt, leaves phosphate of lime as 
 ashes. 
 
 373. Membranes. These are thin transparent sub- 
 stances, destined to line the different cavities of the body, 
 or in form of bags to contain liquids. They are generally 
 
COVERING OF ANIMALS. 
 
 343 
 
 soluble in water, and dissolve into animal glue, which 
 proves that they are principally composed of Gelatine. 
 
 374. The tendons, or sinews are the cords which 
 connect the muscles with the bones. Their composition 
 differs from that of muscular flesh, only by the absence of 
 fibrin. 
 
 ^ 375. The ligaments are the strong bands by which 
 the bones themselves are tied together. They are less 
 soluble in water, and when dried are darker and less trans- 
 parent than the sinews. The rest of their chemical com- 
 position is similar to that of the tendons. 
 
 18. Covering of Animals. 
 
 To these belong the skin, nails, claws, horns, hair, 
 bristles, &-c ; feathers and wool. 
 
 a. Of the skin. 
 
 376. The skin is composed of two parts an external 
 white coat, which is nearly insensible, and is called the 
 cuticle or epidermis ; and an internal one, which is endow- 
 ed with great sensibility, called the cutis vera (true skin). 
 Between these two there is a soft, mucous substance, 
 called the rete mucosum. The external skin (the cuticle) 
 is insoluble in water and the acids, and consists chiefly of 
 the same substance as horn (supposed to be a composition 
 of coagulated albumen and animal glue or gluten). The 
 external skin (cutis vera), on the contrary, contains a 
 number of blood-vessels and nerves, is highly elastic, and 
 may by boiling water, be converted into animal glue ; a 
 proof that its principal ingredient is gelatine. 
 
 This is the reason why the skins of animals yield glue, and 
 why, by the process of tanning, they are capable of being con- 
 verted into leather; because tan, when poured upon animal 
 glue, renders it elastic and impenetrable to water. 
 
 b. Nails, Claws, Horns, Hoofs, Scales, &c. 
 377. These substances, with the exception of the 
 
344 COVERING OF ANIMALS. 
 
 scales of Ji shes, (which are formed of layers of membranes 
 and phosphate of lime), are very nearly allied together 
 with regard to their chemical composition. Their princi- 
 pal ingredient is the same horny substance of which the 
 exterior skin is composed. 
 
 Horns of oxen contain besides, 1 per cent of fat and a 
 peculiar animal substance which may be precipitated by 
 tan. 
 
 The hoofs of horses contain a greater proportion of salts, 
 and yield, by calcination, 4 per cent of phosphate of lime. 
 
 The horns of stags are in their composition similar to 
 bones, but they contain more cartilage. 
 
 c. Hair, Bristles, Feathers, Wool and Silk. 
 
 878. The hair of man consists of thin tubes, of a 
 brown, horny substance, filled with a fat oil, and surround- 
 ed on the outside with a sort of tallow, which, according 
 to its color, gives the hair a black, brown, light, and even 
 red appearance. Black hair, when dissolved in hot potash, 
 leaves a blackish-green residue of oil, iron, and sulphur; 
 red hair leaves red oil, sulphur, and only traces of iron. 
 The ashes of human hair consist of common salt (chloride 
 of sodium), silicious earth and oxide of manganese. The 
 hair of horses leaves, upon calcination, 12 per cent of phos- 
 phate of lime. 
 
 379. Bristles consist principally of the same sub- 
 stance as horn. Feathers are supposed to resemble hair 
 in their chemical composition. The quills consist of pure 
 coagulated albumen. Wool consists likewise of the same 
 substances as hair or bristles ; but it is surrounded by a 
 greasy sweat, composing about 40 per cent of its whole 
 weight. (This sweat is the reason why wool forms soap 
 with the pure alkalies). We are almost entirely ignorant 
 as to the chemical composition of silk. It consists of a 
 peculiar gluey substance, of wax, and a small quantity of 
 essential oil. Yellow raw silk contains, in addition to 
 these ingredients, a peculiar resinous substance. 
 
RECAPITULATION. 
 
 345 
 
 The use of wool and silk, in the manufactory of cloth 
 and silks, is as well known as the application of the other 
 coverings of animals' in domestic economy and the arts. 
 
 RECAPITULATION. 
 
 Questions for Reviewing the most important Principles 
 contained in Chapter VI. 
 
 [ 344.] What are the immediate ingredients which 
 are discovered by the chemical investigation of animal 
 substances ? 
 
 [^ 345.] How may these ingredients be again divided ? 
 Into what four classes may the combustible animal sub- 
 stances be again divided? 
 
 What are the incombustible animal substances which 
 remain as ashes, at the combustion of those which you 
 have just mentioned ? 
 
 [ 346.] What are the ultimate principles of the an- 
 imal body ? How do we know that nitrogen enters largely 
 into the composition of animal substances 1 To what is 
 the offensive smell owing, which accompanies the sponta- 
 neous decomposition of animal substances 1 
 
 [ 347.] What sort of substance is animal jelly (or 
 glue) ? How is it obtained ? What properties does it 
 possess ? What does a solution of animal glue or jelly in 
 water, soon undergo ? 
 
 What changes does glue undergo by boiling ? Into what 
 substances does it become decomposed by dry distillation ? 
 What sort of animal substance is Gelatine^ With what sub- 
 etances does it combine ? 
 
 [ 348.] Where does animal albumen occur ? What 
 does the white of eggs contain ? How may pure albumen 
 be obtained from the white of eggs ? What are the most 
 remarkable properties of albumen 1 What changes does 
 
346 RECAPITULATION 
 
 a solution of albumen in water undergo at a boiling heat ? 
 What sort of smell does it emit when burnt at an open 
 fire ? By what acids may it be precipitated from a solu- 
 tion in water ? Into what elements does it become de- 
 composed by dry distillation ? 
 
 [ 349. Of how many different parts does blood con- 
 sist ? Have these substances much affinity for each other ? 
 How is this ascertained 1 
 
 What are the ingredients of the cerum 1 Into what two 
 substances may the cruor be again separated by washing 
 it with water 1 What are the ingredients of the coloring 
 matter of blood similar to? 
 
 [ 350.] Of how many distinct operations consists the 
 process of respiration ? In what consist the two process- 
 es ? What are the changes which atmospheric air under- 
 goes by the process of respiration ? 
 
 What are the changes which the blood itself undergoes ? 
 
 What is the process of respiration also called, on account of 
 the absorption of oxygen gas ? Why do some philosophers 
 call it the decarbonization of the blood ? 
 
 [ 351.] What are the principal ingredients of milk ? 
 What becomes of the portion of albumen contained in milk 
 when the latter is boiled ? What sort of taste does it im- 
 part to the milk, when it falls to the bottom and becomes 
 burnt ? What change would milk undergo by the process 
 of boiling, if it did not contain a large quantity of water ? 
 
 [ 352.] What becomes of milk when it is suffered to 
 stand still, even when excluded from atmospheric air? 
 What is the oily, unctuous substance called, which rises to 
 the top ? Into what two substances is cream separated by 
 agitation or churning 1 What are the principal properties 
 of butter ? How may butter be preserved, or be made ca- 
 pable of transportation by sea ? 
 
 [ 253.] Into what two substances does milk become 
 decomposed, when suffered to stand until it becomes sour? 
 What substance does the curd of milk form when pressed, 
 salted and dried ? For what purpose is the whey used in 
 Switzerland ? 
 
OF CHAPTER VI. 347 
 
 [ 354.] What substance does the whey of milk yield 
 when separated from butter and curd, and evaporated at a 
 gentle heat ? What'properties does sugar of milk possess ? 
 
 What difference is there between goats' milk, and the milk 
 of cows ? What sort of milk is that of sheep ? What sort of 
 milk is the most watery of all, and contains the least quantity 
 of curd, or butter? 
 
 [ 355.] How is animal mucus obtained ? What are 
 its properties ? What is its principal ingredient in com- 
 bination with water ? 
 
 [ 356.] What animal substances belong to the ani- 
 mal oils and fats ? From what substance is fat extracted 1 
 When is fat called lard 1 When, tallow ? What does 
 fat form when united with potash or soda ? What becomes 
 of it by long keeping ? In what state is the fat of whales 
 obtained ? 
 
 How is spermaceti obtained ? What are its properties ? For 
 what purposes is it used ? 
 
 [ 357.] What acids are contained in the animal body 
 that occur also in the mineral and vegetable kingdoms ? 
 What other acids does it contain, which are peculiar to 
 the animal kingdom ? 
 
 [ 358.] Where is olific acid formed ? What are its 
 properties '? With what substances does it combine ? 
 
 [ 350.] Where does lactic acid occur? By what 
 process is it procured ? What kind of salts does it form 
 with the mineral alkalies ? What property do these salts 
 possess ? 
 
 [^ 360.] What sort of production is mucous acid ? 
 What are its properties ? To what kind of salts does it 
 combine with the mineral bases 1 
 
 [ 361.] What sort of acid is obtained by distilling 
 ants with water ? What are the properties of concentrated 
 formic acid ? What sort of salts does it form with the 
 mineral alkalies? 
 
348 RECAPITULATION 
 
 [ 362.] What are the principal liquids employed in 
 the process of digestion ? 
 
 [ 363.] What sort of liquid is saliva? What are its 
 properties ? What effect does the saliva of men produce 
 on vegetable colors? What changes does saliva undergo 
 in certain diseases ? What are its principal ingredients ? 
 
 [ 364.] Whence proceeds the gastric juice, and in 
 what particular process does it act as a solvent? Of what 
 substances is it composed ? To what is the gastric juice 
 which is thrown up by vomiting similar ? What is the 
 opinion of some physiologists respecting the nature of gas- 
 tric juice ? How does gastric juice operate upon the 
 stomach after death ? 
 
 [ 365.] What are the properties of human bile, in a 
 state of perfect health ? How is bile affected by the acids ? 
 
 What are the principal ingredients of human bile ? 
 Which of these ingredients is particularly affected by sick- 
 ness ? 
 
 What are the ingredients of the bile of oxen, calves, sheep, 
 dogs and cats ? 
 
 366.] What sort of juice is formed by the digestion 
 food in the stomach ? What properties does the chyle 
 of animals possess, 4 or 5 hours after taking food ? How 
 do we know that chyle is specifically lighter than blood ? 
 How does chyle affect the color of violets ? What chang- 
 es does it undergo when taken from the thoracic duct ? 
 What are the properties of the coagulum, and what those 
 of the serous part into which chyle separates ? 
 
 What are the ingredients of the ashes, produced by 
 burning dry chyle ? 
 
 [^ 367.] What kind of substance is the brain of men 
 and quadrupeds? Of what ingredients does it principally 
 consist ? 
 
 In what respect do the nerves of men differ from the 
 brain ? 
 
 What difference is there between the chemical compo- 
 sition of the brains of calves or oxen,, and that of men ? 
 
 of foe 
 
OF CHAPTER VI. 349 
 
 [$ 368.] What kind of substance is fibrin or animal 
 gluten ? In what vyays may it be produced in its simple 
 form 1 What are it's properties ? Of what elements does 
 it consist? 
 
 [ 369.] Of what substances are the bones and teeth 
 of animals composed ? What do all bones contain ? By 
 what means may the cartilaginous matter be extracted 
 from them ? How are bones affected by cold muriatic 
 acid? 
 
 What changes do the bones of children gradually undergo, 
 until they grow to be adults ? 
 
 How are bones acted upon by hot muriatic acid ? What 
 substances do they yield by dry distillation ? 
 
 [^ 370.] What is the chemical composition of the 
 teeth and the enamel similar to ? 
 
 What remarkable discovery did Dr Autenrieth, df Tubigen, 
 make with regard to the bones of children and old men ? 
 
 Into what does cartilage become changed by boiling it 
 for some time in water ? 
 
 [ 371.] Where is the marrow seated ? Of what does 
 it principally consist? 
 
 [ 373.] What does muscular flesh probably consist 
 of? What does it yield when mixed with cold water ? 
 What does it yield when mixed with warm water ? 
 
 [ 373.] What kind of substance are the membranes? 
 What property do they generally possess ? 
 
 [ 374.] What office have the tendons or sinews ? In 
 what respect does their composition differ from muscular 
 flesh ? 
 
 [ 375.] What sort of substance are the ligaments ? 
 In what respect does their chemical composition differ 
 from that of the sinews ? What is the rest of their com- 
 position similar to ? 
 
 [ 376.] Of how many different parts does the skin 
 consist? What is the name of the external white coat 
 
 30 
 
350 RECAPITULATION 
 
 which is nearly insensible ? What, that of the internal one, 
 which is endowed with great sensibility ? What kind of 
 substance is situated between these two ? What is the 
 composition of the epidermis? What that of the cutis 
 vera ? 
 
 What is the reason that the skins of animals yield glue, or 
 are capable of being converted into leather ? 
 
 [ 377.] W'hat is the principal ingredient of the nails, 
 claws, horns, hoofs and scales ? 
 
 What do the horns of oxen contain, besides the sub- 
 stance contained in the nails ? 
 
 What, the hoofs of horses ? 
 
 What substance are the horns of stags similar to ? 
 
 [^ 378.] What does the hair of man consist oft 
 What residue does black hair leave, when dissolved in hot 
 potash ? What, red hair ? What are the ashes of hu- 
 man hair composed of? What do the hair of horses leave 
 upon calcination ? 
 
 [ 379.] What are bristles composed of? What is 
 the composition of feathers similar to? What do the 
 quills consist of? Of what substances does wool consist ? 
 What is the chemical composition of silk? What does 
 yellow raw silk consist of? 
 
GERMINATION OF SEEDS. 351 
 
 CHAPTER VII. 
 
 OP THE CHEMICAL PROCESS ACCOMPANYING THE DEVEL- 
 OPMENT, LIFE, AND DEATH OF ORGANIZED BODIES. 
 
 A. GERMINATION OF SEEDS. 
 
 $ 380. From the experiments which have been made 
 with the seeds of different plants, we are able to lay down 
 the following principles : 
 
 I. No seed can germinate without moisture. Water 
 alone, however, is insufficient for this purpose. Seeds 
 thrown into water die, and become putrid. 
 
 2. Atmospheric air, or oxygen gas, must have an uninter- 
 rupted access to it. 
 
 No germination takes place in pure carbonic acid, hydrogen, 
 or nitrogen gas, or very rarified air. But these gases do not 
 destroy the seed ; they merely prevent its development into a 
 plant. 
 
 3. It is necessary that the temperature should be at least 
 above the freezing point of water. 
 
 Different seeds require different degrees of temperature ; 
 but none germinate at a temperature as low as 32 Fahrenheit. 
 
 B. PROCESS OF NUTRITION NECESSARY TO LIFE. 
 
 381. Both plants and animals have certain external 
 organs, which enable them to take up a greater or less 
 quantity of gases, liquids, and even solids, destined to 
 serve them as nutriment. They decompose these substan- 
 ces into their chemical ingredients, appropriate to them- 
 
352 VINOUS FERMENTATION. 
 
 selves a certain portion of them, and rid themselves of the 
 rest. By this continued process of absorption and expul- 
 sion, the whole vegetable and animal life is constantly 
 renovated, and those animal products produced, which we 
 have described in the preceding chapters. 
 
 The effect of atmospheric air on the organization of 
 plants is similar to that produced by the respiration of ani- 
 mals, (see 350). They absorb a certain portion of oxy- 
 gen, and yield in its state an equal volume of carbonic 
 acid gas. 
 
 C. OF THE SPONTANEOUS DECOMPOSITION OF ORGANIC 
 SUBSTANCES. 
 
 382. Every organized body, immediately after its 
 death suffers a spontaneous decomposition of its chemical 
 ingredients, which soon or late become dissolved into 
 their elements. With regard to vegetables, this spontane- 
 ous process has received the name of fermentation. 
 
 $ 383. The immediate products of the spontaneous 
 decomposition of vegetables differing from each other es- 
 sentially in nature and quality, naturally lead us to sup- 
 pose that there are different kinds of fermentation ; but 
 we distinguish more especially between the vinous and 
 acetous. Both kinds require, 
 
 1. The presence and joint action of water. 
 
 2. An uninterrupted access of air, (to yield a sufficient 
 quantity of oxygen). 
 
 3. A proper degree of temperature. (A very high tem- 
 perature disturbs, and a very low temperature retards the 
 process of fermentation.) 
 
 1. Vinous Fermentation. 
 
 384. The product of this fermentation is a vinous, 
 or at least a spirituous liquid, (wine, beer, cider, &c ) 
 hence its name. Sugar, or sugary substances, are the 
 only vegetable matters capable of vinous fermentation. But 
 for this purpose they need the assistance of the ferment ous 
 principles of lees, albumen, and gluten. 
 
VINOUS FERMENTATION. 353 
 
 In order that the fermentous principle shall act upon 
 the sugar, it is necessary that it should be in close contact 
 with the latter. THis is the reason why no fermentation 
 takes place in the grape itself, where both substances are 
 in a state of separation. It explains also, why the presence 
 of water is indispensable ; because by dissolving both the 
 sugary and the fermentous principle, it brings both sub- 
 stances in immediate contact. The vinous fermentation 
 of sugar may therefore be considered as the result of its 
 decomposition by the fermentous principle. 
 
 Phenomena accompanying Vinous Fermentation. 
 
 3S5. The phenomena which accompany the vinous 
 fermentation of vegetables, are the following : 
 
 1. As soon as it commences, a motion is perceived in 
 the interior of the liquid, its temperature rises by several 
 degrees, and it becomes turbid. 
 
 2. The volume of the liquid is increased; a thick 
 scum is forming on its surface, and a very considerable 
 quantity of carbonic acid is produced, which is impreg- 
 nated with alcohol. (Hence we infer that the sugar is de- 
 composed into carbonic acid and alcohol.)* 
 
 3. When these phenomena have continued for some 
 time, the volume of the liquid contracts again, the tem- 
 perature is diminished, the scum disappears, no more car- 
 bonic acid is produced, and a precipitate is formed, which 
 renders the liquid clear and transparent. 
 
 4. Instead of the sweet taste which the liquid had be- 
 fore the fermentation, it has now a pungent taste, an 
 aromatic flavor, its specific gravity is diminished, and it 
 
 * This agrees perfectly with the analysis of sugar, alcohol, and 
 carbonic acid : 
 
 r. C 3 equivalents of carbon, 
 Sugar consists of J 6 4 do O f oxygen. 
 
 Carbonic acid consists of 1 equiv. of carbon and 4 of oxygen, 
 Alcohol do 2 do of carbon and 2 of oxygen. 
 
 Amounting together to 3 equiv. of carbon and 6 of oxygen, 
 30* 
 
354 ACETOUS FERMENTATION. 
 
 possesses intoxicating qualities, in a word it has become 
 transformed into wine. 
 
 386. Wine, the product of vinous fermentation, must 
 be considered as a peculiar substance, the various kinds 
 of which agree in the following characterizing properties : 
 
 1. All kinds of wine are specifically lighter than water, 
 and have more or less color. 
 
 2. All of them have a peculiar, pungent taste, and an 
 aromatic flavor. 
 
 3. They are all intoxicating (in a greater or less degree). 
 
 4. They yield alcohol by distillation. 
 
 Most of the properties of wine are probably owing to 
 the last mentioned circumstance, for which reason many 
 distinguished chemists consider alcohol as the product of 
 vinous fermentation. 
 
 The difference in taste, color and intoxicating effects of the 
 various kinds of wine is owing, 
 
 1st. To the greater or less quantity of water which they 
 contain. 
 
 2d. To the vegetable acids which enter into their chemical 
 composition (citric, malic, tartaric and acetic acid ; which 
 were contained in the liquid either before or during fermen- 
 tation). 
 
 3d. To the peculiar nature and properties of the coloring 
 matter. 
 
 4th. To the quantity of sugar ; and 
 
 5th. To the proportion of mucilage, gluten, and vegetable 
 extract. 
 
 Upon this last mentioned circumstance depends the main 
 difference between beer, cider, and the wine of grapes. 
 
 2. Acetous Fermentation. 
 
 387. By this name we distinguish that kind of fer- 
 mentation of vegetable matter, the product of which is 
 vinegar. A great number of vegetable substances, partic- 
 ularly the different kinds of gum and vegetable extracts, 
 are capable of acetous fermentation ; but they need for 
 this purpose in addition to the fcrmcntous principles 
 also a free access of air, to absorb a sufficient quantity of 
 

 PUTREFACTION. 355 
 
 oxygen, and a temperature of from 74 to 84 degrees Fah- 
 renheit. 
 
 A limited portion of alcohol seems to be favorable to the 
 process, and increases the quantity of vinegar; but the pres- 
 ence of sugar is believed to be a considerable obstacle. 
 
 388. The phenomena attending the acetous fermen- 
 tation are similar to those which accompany the vinous 
 decomposition of vegetable substances (see the last section). 
 They consist in an internal movement, increase of tem- 
 perature, development of carbonic acid, formation of 
 fibrous matter, which renders the liquid turbid, &,c ; but 
 the liquid acquires gradually an acid taste and smell, un- 
 til it becomes changed into what is properly called vinegar. 
 This product is found upon distillation to be nothing else 
 but very dilute acetic acid (see 334), mixed, however, 
 with different vegetable substances, such as gluten, gum, 
 vegetable extract, &c, upon which depend principally the 
 quality and kind of vinegar. 
 
 It has already been mentioned, that acetic acid, the prin- 
 cipal ingredient of vinegar, is also obtained by dry distillation 
 of wood, and other vegetable and animal matter. 
 
 3. Of the Process of Putrefaction. 
 
 389. One of the principal characteristics of animal 
 substances is their spontaneous decomposition after death, 
 which is called putrefaction. This is a process analogous 
 to the fermentation of vegetable matter, and leads to the 
 same results that is, to a complete destruction of all 
 chemical combinations, as they existed in the animal dur- 
 ing its life-time ; although the products of putrefaction and 
 the phenomena which are dependent on it, are essentially 
 different from those which are produced by the fermenta- 
 tion of vegetable substances. 
 
 There are a few vegetables capable of exhibiting the phe- 
 nomena of putrefaction. These are in their nature and chem- 
 ical composition very much similar to animal matter, and con- 
 tain (like cabbage) a considerable portion of nitrogen. It is 
 on this account some philosophers speak of the putrid fermen- 
 tation of vegetables. 
 
356 PUTREFACTION. 
 
 ^ 390. The conditions under which putrefaction takes 
 place are the same as those which are indispensable to the 
 fermentation of vegetables viz : presence and coopera- 
 tion of water, free access of air, and a proper degree of 
 temperature. 
 
 It is highly probable that there are different degrees and 
 kinds of putrefaction, according to the different classes and 
 kinds of animals ; but the whole process has, as yet, been too 
 little investigated to describe more than the general phenom- 
 ena which accompany it. 
 
 Putrefaction with free access of Air. 
 
 391. The putrefying substance (commonly muscular 
 flesh and meat) assumes first a peculiar musty appearance 
 and smell, which soon afterwards becomes sour, pungent, 
 and fetid. Its taste becomes exceedingly nauseous ; the 
 cohesion of its particles is considerably diminished, the 
 organic texture entirely destroyed, arid the whole changed 
 into a soft, pappy brown (sometimes greenish) mass. Car- 
 bonic acid gas is now given off in great profusion ; but 
 the quantity of inflammable (hydrogen) gas is visibly di- 
 minished. By degrees the fetid smell ceases ; the mass 
 obtains again a certain degree of solidity, and becomes 
 converted into an earthy substance of a blackish color. 
 This is the end of the whole process. 
 
 If the process of putrefaction is carried on with a small quan- 
 tity of water, a great portion of inflammable gas (carbureted 
 hydrogen) is given off. If much water be added, then, very 
 little gas is developed ; but the water assumes an insufferable 
 fetid smell.* 
 
 Putrefaction with little or no access of Air. 
 
 392. The phenomena accompanying this sort of 
 spontaneous decomposition of animal substances are en- 
 tirely different from those we have just mentioned ; partic- 
 ularly if the animal body be also secluded from day-light, 
 
 * The cause of this excessively offensive odor is not yet suf- 
 ficiently ascertained. The formation of. carbureted, phosphureted, 
 aud sulphureted hydrogen alone cannot account for this phenomenon. 
 
RECAPITULATION. 357 
 
 and submitted to a moderate degree of temperature. Pu- 
 trefaction advances, then, but very slowly ; the odor which 
 it emits is musty, but not fetid ; and the whole is chang- 
 ed into a blackish, powdery substance, bearing great re- 
 semblance to animal charcoal At the same time a con- 
 siderable quantity of nitric acid is formed. 
 
 The process of putrefaction may be retarded for a long time 
 by the assistance of alcohol, the acids, some of the salts, the 
 volatile or essential oils, and by the exclusion of atmospheric air. 
 The mummies of the Egyptians, and the anatomical preparations 
 which are kept in spirits of wine, and which, in this state, re- 
 sist putrefaction even for centuries, are sufficient proofs of this 
 assertion. 
 
 393. All combustible substances contained in the 
 animal body are thus subjected to destruction by water, 
 air, and the joint operation of the elements. But the 
 products of their spontaneous decomposition are not 
 entirely lost; they serve to enliven and nourish the 
 vegetation of plants, which, in their turn, afford nutriment 
 to animals ; and so does this change from life to death and 
 decomposition, and from decomposition again to life and 
 death, continue to set the springs of human industry in 
 motion, and affords, by a wise distribution of Providence, 
 the means of our nutriment and comfort. 
 
 RECAPITULATION. 
 Containing Questions for Reviewing Chapter VII. 
 
 [ 380.] What principles are we enabled to lay down 
 from experiment respecting the germination of seeds? 
 
 [ 381.] What are all animals and plants provided 
 
 with, for the purpose of nutrition ? What do they do with 
 
 he substances they take up by these organs? What 
 
 end is attained by this continued process of absorption and 
 
 expulsion ? 
 
358 RECAPITULATION 
 
 What is the effect of atmospheric air on the organiza- 
 tion of plants, similar to 1 Why ? 
 
 [ 382.] What change does every organized body 
 suffer, immediately after death ? What is this process call- 
 ed with regard to vegetables? 
 
 [ 883.] What are the principal kinds of fermenta- 
 tion ? What do both kinds of fermentation require ? 
 
 [< 384.] What sort of product is produced by vinous 
 fermentation ? What vegetable substances are alone ca- 
 pable of vinous fermentation ? What assistance do they 
 need for this purpose ? 
 
 What is necessary in order that the fermentous princi- 
 ple should act upon the sugar 1 What is this the reason 
 of? Why is the presence of water necessary for this kind 
 of fermentation ? As what, therefore, may the vinous fer- 
 mentation of sugar be considered. 
 
 [ 385.] What phenomena accompany the vinous fer- 
 mentation of vegetables ? 
 
 [ 386.] What characterizing properties have all kinds 
 of wine ? 
 
 To what peculiar ingredient of wine are most of its in- 
 toxicating qualities owing ? 
 
 What are the causes of the difference in taste, color, and 
 intoxicating effects of the various kinds of wine ? 
 
 On what depends the principal difference between beer, 
 cider, and the wine of grapes? 
 
 [ 387.] What do you understand by the acetous fer- 
 mentation of vegetable substances ? What vegetable sub- 
 stances are capable of this kind of fermentation ? What 
 do they need for this purpose, in addition to the ferment- 
 ous principle ? 
 
 Is the presence of alcohol favorable or a hindrance to acetous 
 fermentation ? Is this also the case with sugar ? 
 
 [ 388.] What are the changes produced by acetous 
 fermentation ? What is this product, upon distillation, 
 found to be composed of? 
 
OF CHAPTER VII. 359 
 
 [$ 389.] What is the spontaneous decomposition after 
 death of all animal substances, called ? What is this 
 process analogous to ? To what results does it lead ? 
 
 What vegetable substances are capable of exhibiting the 
 phenomena of putrefaction ? What is this sort of putrefaction 
 of vegetables, by some philosophers called ? 
 
 [ 390.] What are the conditions under which putre- 
 faction takes place ? 
 
 [ 391.] What phenomena accompany the putrefaction 
 of animal substances with free access of air. 
 
 What kind of gas is given off, when the process of putrefac- 
 tion is carried on with a small quantity of water ? What takes 
 place when a large quantity of water is added? 
 
 [ 392.] What phenomena accompany the putrefaction 
 of animal substances with little or no access of air ? 
 
 By what means may the process of putrefaction be retarded 
 for a considerable length of time ? 
 
APPENDIX. 
 
 ON THE STEAM ENGINE. 
 
 [!T is not to be expected that a complete treatise on so com- 
 plicated a machine should be annexed to an elementary trea- 
 tise on Chemistry ; but an acquaintance with its principal 
 parts being absolutely indispensable to a correct understanding 
 of a great number of valuable improvements in mechanics and 
 the arts, we have endeavored to give to the learner a brief 
 sketch of its most important elements.] 
 
 394. We have already had occasion to allude to the 
 elasticity of steam, and gave, in 35, Fig. XCIV, an ex- 
 ample of its power to raise a piston that shall work air- 
 tight in a cylinder. Now it is easily conceived that if the 
 piston rod is attached to some lever or wheel, it may com- 
 municate to them a certain force or motion, which by a 
 proper arrangement may be transferred to any particular 
 part of the machine where we wish it to operate. A ma- 
 chine constructed for this purpose, and in which the elas- 
 ticity of steam is employed for the moving force, is called a 
 steam engine. 
 
 395. In the experiment represented in Fig. XCIV, 
 page 84, the piston is only forced up by the expansive pow- 
 er of the steam ; but when the steam is condensed and a 
 vacuum created under the piston, it is the pressure of the 
 atmosphere which forced the piston down again. En- 
 gines constructed upon this principle are called atmos- 
 pheric engines. They require the cylinder to be cooled 
 down after each stroke of the piston, in order to pro- 
 duce the necessary condensation of the steam, and 
 
APPENDIX. 
 
 361 
 
 the subsequent creation of a vacuum for the moving down 
 of the piston. This is naturally the cause of a great loss 
 of fuel, because each new stroke of the piston must be 
 produced by the forming of a fresh quantity of steam, and 
 a subsequent condensation of it, by cooling down the cyl- 
 inder. Besides this inconvenience, the motion of an at- 
 mospheric machine cannot be regulated like that of. the 
 engine we are about to describe. 
 
 Fig. CXXXVI. 
 
 396. Fig. CXXXVI represents the most essential 
 part of what is called a double working engine. B repre- 
 sents a section of the boiler, provided with a safety- 
 valve, in order to admit of the passing of the steam in case 
 its elastic force should endanger the safety of the machine. 
 The pressure upon this valve may be regulated by the 
 movable weight D, suspended from the end of the lever 
 D E. V.U S T represents the barrel or cylinder, to which 
 the piston R is fitted in such a way as to admit of its 
 moving up and down, without allowing the least quantity o 
 water or steam to escape between it and the barrel. To the 
 piston is attached the piston-rod R K, which is also made 
 cylindrical, and is kept air and steam tight by the stuffing- 
 box K, made of leather and stuffed with wool, tow, or some 
 other elastic substance, to enable the rod to work freely up 
 and down, without permitting the escape of steam 
 
 31 
 
362 APPENDIX, 
 
 The pipe P, which is called the steam-pipe, 
 cates with the boiler, and is destined to convey the steam 
 to the barrel V U S T. It is divided into two branches, 
 each of which may be closed or opened by means of cocks 
 or valves placed in L and M, so as to admit the steam 
 either below or above the piston, according as the piston 
 is to rise or to descend in the barrel. 
 
 On the opposite side of the cylinder there is a similar 
 tube W, called the edttefton-pipe, likewise divided into two 
 branches, and communicating with the barrel in U and T. 
 This pipe is intended for the discharge of steam after it 
 has raised or forced down the piston, and is, in O and N, 
 provided with valves, which may be opened or closed, ac- 
 cording as we wish to discharge the steam from above or 
 below the piston, viz : when the valve O is opened the 
 steam will be discharged from above the piston ; and when 
 the valve N is opened, the steam will escape from below it. 
 
 The eduction pipe W, is conducted into what is called 
 the condenser C. This is a vessel destined for the con- 
 densation of the discharged steam. It must for this 
 purpose be constantly kept cool, which is effected by sur- 
 rounding it with cold water, or placing it in a cistern 
 the cold water well filled with water. To promote the 
 rapid' condensation of the steam a stream of cold water is 
 constantly discharged into the condenser. 
 
 The pump Q,, which in its construction is similar to a 
 common pump (see Natural Philosophy, Chapter V), is a 
 very essential part of the low-pressure steam engine. By a 
 mechanical contrivance it is connected with, and worked 
 by the rising and descending of the piston rod, and serves 
 for the important purpose of creating a constant vacuum 
 by freeing the condenser from air and water as fast as the 
 steam is discharged into it. Without this pump the con- 
 denser would soon be filled with air and water, and the dis- 
 charge of the steam be rendered impossible, which would 
 arrest the operation of the whole machine. This mode of 
 creating a vacuum, is one of the chief improvements of the 
 steam engine, for which we are indebted to James Watt, 
 a celebrated English engineer, whose merits in this branch 
 of the arts have entitled him to the gratitude of the age. 
 
APPENDIX. 363 
 
 $ 397. When the machine is to be set in operation, 
 the water in the boiler is heated by the furnace, and by 
 that means converted into steam. The four valves, L, M, 
 N, O, are then all opened, so as to admit the steam from 
 the boiler, above and below the piston, and at the same 
 time to allow its escape into the condenser, and from 
 thence through the valve of the pump Q, into the open air. 
 The object of this is to expel the air from every part of the 
 machine, in order to create a vacuum by the subsequent con- 
 densation of steam. This process is called blowing through. 
 When this is done, the valves M and O are closed, in 
 order to admit the steam only above the piston, through 
 the valve L, and to allow the escape of it from below the pis- 
 ton, through N and the eduction pipe U, into the condens- 
 er. This forces the piston down to the bottom of the barrel, 
 and imparts the first motion to the engine. The valves L 
 and N are now closed, and O and M opened. By this 
 means the steam from the boiler is, through M and S, admit- 
 ted below the piston, while the steam above the piston is 
 permitted to escape through the valve O, into the condenser. 
 The effect of this operation is the forcing up of the piston to 
 the top of the barrel. The valves M and O, being again 
 closed in their turn, and L and N opened, a fresh portion 
 of steam from the boiler forces the piston down again to 
 the bottom of the barrel ; and so does the alternate open- 
 ing and closing of the valves M, O, and N, L, respectively, 
 admit the steam below or above the piston, and produces 
 the moving up and down of the piston rod, by which means 
 the whole machinery is set in motion. 
 
 The construction of the engine is commonly such that 
 the closing and opening of the valves, as well as the work- 
 ing of the air pump Q, is effected by levers connected 
 with a piston-rod ; and a portion of the power of the engine 
 is therefore always expended in working these parts. 
 
 The pressure of the steam is averaged to be 151bs. to the 
 square inch, and is therefore proportional to the surface of 
 the piston, or the surface of a parallel section of the barrel. 
 Thus a pressure of several hundred horse power may be 
 produced if the barrel be only wide enough for this purpose. 
 
 EXAMPLE. If the horizontal diameter of the barrel were 
 3 feet, the area of a sector would, according to the rules of 
 
364 
 
 APPENDIX. 
 
 geometry,* be 1017.8784 square inches, and the pressure 
 of the steam 1 5,268 Ibs ! If the horizontal diameter of the 
 cylinder were 6 feet, then the pressure would amount to 
 61,072 Ibs. ! and so on. We see from this that we can at 
 pleasure increase or decrease the power of the engine by 
 widening or contracting the barrel and piston, provided the 
 materials are strong enough to resist the force of the steam. 
 For in proportion to the pressure of the steam, the piston 
 will be moved up and down with a greater or less force ; 
 which, therefore, ought to be regulated according to the 
 purpose for which the engine is constructed. 
 
 398. If the motion to be produced by the machine is 
 rolary, as is, for instance, the case in the construction of 
 steam-boats, then it is only necessary to connect the piston- 
 rod with one end of a lever, and the wheel which is to be 
 turned, with the other, as is represented in the adjoining 
 figure. 
 
 Fig. CXXXVII. 
 
 B 
 
 The moving up and down of the piston, sets the lever 
 A B, in motion, which in its turn moves the wheel W, in 
 
 * The area of a circle is found by multiplying the squares of the 
 radius by the number 31.1416. (See Gruad's Geometry 4 Part I) 
 
APPENDIX. 
 
 365 
 
 the same manner as a grindstone is turned by a crank 
 moved by the motion of the foot. If the motion to be 
 communicated is to act perpendicular or horizontal, then 
 this is effected by a system of levers constructed in various 
 ways, and the operation of which is easily understood by 
 the inspection of the machine. 
 
 From what we have thus far explained, the learner will 
 be able to understand how the elastic force of steam is ca- 
 pable of setting a complicated machine in motion, and 
 that this force may be increased to an almost infinite extent, 
 transcending by far the effects produced by any other agent 
 in nature. We will now proceed to explain separately 
 the construction and use of the safety-valve, and the manner 
 in which the valves L M, N O, are alternately opened and 
 closed by the operation of the machine itself; after which 
 we shall give a short description of Watt's low-pressure 
 engine, now commonly used for propelling steam-boats. 
 Fig. CXXXVIII, 
 
366 APPENDIX. 
 
 399. Fig. CXXXVIII represents separately the boil- 
 er and safety-valve of a steam engine. The valve V, as may 
 be seen from the figure, is shaped conically, and connected 
 with a lever C D, which, in D, is charged with a small weight 
 W, to keep the valve down. This weight may be moved 
 further from, or nearer to the valve, according as we wish 
 the steam in the boiler to attain a greater or less degree of 
 elasticity. When it is moved nearer the fulcrum C, it 
 will, according to the law of the lever, require less force to 
 lift it (to open the valve) than when it is removed further 
 from it. 
 
 Now, the elasticity of the steam in the low-pressure en- 
 gine being equal to about 15 Ibs. to the square inch, we 
 can easily compute the pressure which it will exercise up- 
 on the lower surface of the valve ; to counteract which it 
 will only be necessary to depress the valve with a power 
 equal to the same weight. But for this purpose we need 
 not attach any weight to the lever C D ; because the at- 
 mosphere itself has that power (Natural Philosophy, Chap. 
 V) ; the valve, therefore, without the weight, could not 
 be opened until the elasticity and consequent pressure of 
 the steam should exceed 15 pounds to the square inch. It 
 is, nevertheless, necessary to attach a small additional 
 weight (not more than two or three Ibs.) to the lever C D, 
 in order to increase the elasticity of the steam in the boil- 
 er to a degree which enables it to blow out with sufficient 
 force to prevent the admission of atmospheric air into the 
 machine. 
 
 400. We will now mention an improvement of Mr 
 Murray's, consisting in what is called a single slide, in- 
 stead of the valves for the admission and escape of steam. 
 It consists, as may be seen from the following two figures, 
 CXXXIX and CXL, in a slide S, capable of being moved 
 up and down in the direction from L to M, which is 
 
APPENDIX. 
 Fig. CXXXIX. 
 
 367 
 
368 APPENDIX. 
 
 effected by means of the levers M N O, and an excentric, 
 which is moved by the turning of the wheel, as is repre- 
 sented in Fig. CXLI, page 369. The construction 
 of the machine is such that when the slide is in the 
 position represented in Fig. CXXXIX, the steam from 
 the boiler is admitted through the steam pipe P, into the 
 pipe q r, and thence through the opening u, into the lower 
 part t y of the barrel. The piston will, in this case, be 
 forced up to the extremity of the barrel, while the steam 
 from above the piston is discharged through a b d n o e, into 
 the condenser C. The next turn of the wheel places the 
 slide S, in the position represented in Fig. CXL. The 
 steam from the boiler is now prevented from entering the 
 pipe q r, connected with the lower extremity of the barrel ; 
 but it has free access through / d ) into the pipe a 6, which 
 conducts it to the upper extremity of the barrel. This 
 will have a tendency to force the piston down, provided 
 the steam from below the piston can find its way into the 
 condenser. But this is actually provided for by the pipe 
 t u r q, which is now open in n, and admits of the steam 
 passing through o e, into the condenser.* 
 
 We see from these figures how the motion of the piston 
 rod itself, acting on the levers and the wheel, may serve 
 to open and close the valves, and how, by a proper ar- 
 rangement of the different parts of the engine, one may be 
 made to act upon the other, so that the very power which 
 sets the engine in motion, is in its turn, governed by the 
 motion of which it is the cause. 
 
 401. The next figure shows the construction of the 
 different parts of the engine, and the manner in which 
 they are all worked by the simple motion of the piston rod . 
 After what has gone before, the learner will find no difficulty 
 in understanding the various arrangements of the machine. 
 
 * The two last figures, as well as Fig. CXLI, are copies of Mr 
 Claxton's models of the steam engine. The apparatus itself appears 
 to be remarkably simple, and eminently calculated to give a clear 
 and distinct idea of the essential parts of this important machine. Mr 
 Claxton is one of the most skilful mechanics in Boston, and has con- 
 structed a variety of physical and chemical apparatus, well answering 
 the purposes of illustration in schools. 
 
APPENDIX. 
 
 309 
 
 Fig. CXLT represents the connexion between the 
 different parts of the engine we have just described. 
 
 B represents the boiler. 
 
 C represents the safety valve. 
 
 F, E are what mechanics call steam and water gauges 
 respectively. They consist of hollow tubes provided with 
 stop-cocks. The gauge F, as may be seen from the figure, 
 has its lower end immersed in the water : but the gauge E, 
 does not communicate with the surface of the liquid. 
 When the stop-cock of the gauge E is opened, nothing but 
 steam must rush forth, otherwise it is a sign that there is 
 too much water in the boiler ; but when the stop-cock of 
 the gauge F is opened, no steam must pass, else it is a 
 sign that the water is too high. 
 
 M represents the cylinder or barrel. 
 
370 APPENDIX. 
 
 N O the piston and piston-rod, 
 
 P represents the steam-pipe, conducting the steam from 
 the boiler alternately above and below the piston, 
 
 S represents Murray's single slide, by the motion of 
 which the steam is alternately admitted and discharged 
 from the barrel, 
 
 K represents the condenser, enclosed in the water well, 
 
 A represents the beam or lever, moved up and down by 
 the piston rod, 
 
 Q, represents the air-pump, worked by the beam or 
 lever, 
 
 H the wheel, and 
 
 G represents the governor. This is opened or closed 
 by the centrifugal force produced by the revolution of the 
 fly wheel (see Natural Philosophy, Chap. 1), and is con- 
 nected with a kind of valve in the steam pipe, so that when 
 it opens widest, that is, when the wheel turns fastest, it 
 partly closes the communication between the boiler and the 
 barrel, by which means a smaller quantity of steam passes 
 into the cylinder, and causes the engine to work more 
 slowly. The object of the governor, or regulator is, there- 
 fore, none other than to introduce greater regularity into 
 the working of the machine by regulating the quantity of 
 steam passing into the barrel. 
 
 Finally, R represents the crank rod, which gives motion 
 to the wheel. 
 
 The remainder of the construction, as represented in the 
 engraving, is sufficiently plain from inspection, and from 
 the previous explanation of its parts. 
 
 402. Before we conclude, it behooves us to say a 
 few words on the difference between low pressure and high 
 pressure engines. 
 
 The high pressure engine is one which has neither con- 
 denser nor air-pump, but in which the steam from above 
 or below the piston is immediately discharged into the at- 
 mosphere. No vacuum, therefore, is created in the barrel, 
 and the atmosphere having always access to that surface 
 of the piston which is opposite to the steam, exercises on 
 that side a pressure of 15 Ibs. on the square inch. This 
 pressure of atmospheric air must be overcome by the 
 
APPENDIX. 37| 
 
 steam, in addition to the power which it needs for setting 
 the machinery in motion ; and it will, therefore, require a 
 much greater elasticity of steam to set a high pressure en- 
 gine in motion, than is needed for a low pressure engine. 
 For while. a steam pressure of 15 Ibs. on the square inch 
 is amply sufficient for all the operations of a low press- 
 ure engine (with condenser and air-pump), a pressure of 
 steam, equal, at least, to 15 Ibs. on the square inch is re- 
 quired in the high pressure engine, merely to counter- 
 act the pressure of the atmosphere ; and the machine, 
 therefore, can only work with the surplus of power which 
 it has over the atmosphere. The principal advantage of a 
 low pressure engine consists, therefore, in the complete ex- 
 clusion of atmospheric air, which is effected by the conden- 
 ser and the air-pump. But the high pressure engine occu- 
 pies less space, and when its boiler and barrel are sufficient- 
 ly strong, can exercise a powerful pressure with very little 
 steam. Besides this, the water with which it is necessary 
 to surround the condenser of the low pressure engine can- 
 not always be readily procured ; or the room in which the 
 machine is to work does not admit of its presence. In all 
 these cases high pressure engines are employed in prefer- 
 ence to low pressure engines ; and it is on this account, 
 principally, that they are exclusively used in the construc- 
 tion of locomotives. 
 
 QUESTIONS ON THE STEAM ENGINE. 
 
 [^ 394.] What is a machine called in which the 
 elasticity of steam is the moving force ? 
 
 [ 395.] By what power is the piston moved up, in 
 the atmospheric engine ? By what power is it forced 
 down again, when a vacuum is created under the piston ? 
 What does this kind of engine require after each stroke of 
 the piston ? 
 
 [ 396.] Explain Fig. CXXXVI. What is the use 
 
372 APPENDIX. 
 
 of the safety valve ? What that of the stuffing-box 1 What 
 is the use of the steam-pipe ? What that of the valves re- 
 presented in the figure 1 What office has the eduction pipe ? 
 In what consists the use of the condenser ? How must the 
 condenser constantly be kept for this purpose ? What is 
 the use of the cold water well ? What is the use of the 
 pump ? What would soon take place if this pump ceased 
 to work 1 
 
 [Sj 397.] What is the first step taken in order to set the 
 engine to work ? What is the process you have just de- 
 scribed, called ? What rs the next step in order to move the 
 piston down again ? By what means is the piston after- 
 wards raised again to the top of the barrel ? 
 
 What is the average pressure of steam on the square 
 inch in the low pressure engine ? By what means may we, 
 at pleasure, increase or diminish the power of this engine ? 
 
 [$} 398.] By what means does the motion of the piston 
 rod communicate motion to the other parts of the machine ? 
 Explain Fig. CXXXVII. 
 
 [ 399.] Explain Fig. CXXXVIII. How must the 
 safety valve be shaped ? What is the pressure of the 
 steam on the lower surface of the valve 1 What is the ave- 
 rage pressure of the atmosphere on the exterior surface 
 of the valve equal to 1 For what purpose is an additional 
 weight attached to the lever 1 
 
 [& 400.] Explain Murray's single slide, represented in 
 Figs. CXXXIX and CXL. 
 
 [ 401.] Explain the different parts of the steam en- 
 gine, as represented in Fig. CXLI ? 
 What does B represent ? 
 What, C D 1 
 
 What is the use of the steam and water gauges ? 
 Where is the barrel represented ? 
 Where, the piston-rod ? 
 Which is the steam pipe ? 
 Where is the single slide ? 
 Where is the condenser represented ? 
 What is the object of the governor or regulator ? 
 
APPENDIX. 373 
 
 402.] In what respect does the construction of the 
 high pressure engine differ from that of the low pressure 
 engine ? Does the' high pressure engine require more or 
 less elasticity of steam, to be set in motion, than the low 
 pressure engine ? Why ? In what, therefore, consists the 
 principal advantage of the low pressure engine '? What, 
 on the contrary, are the advantages of the high pressure 
 engines ? What sort of engines are used for locomotives ? 
 
374 
 
 APPENDIX. 
 
 TABLE II. 
 
 SCALE OF CHEMICAL EQUIVALENTS (OR ATOMIC WEIGHTS), 
 In which hydrogen gas is taken for unity, after Berzelius. 
 
 Oxygen, 
 
 8 
 
 Gold, 
 
 66 
 
 Hydrogen, 
 
 1 
 
 Platinum, 
 
 48 
 
 Chlorine, 
 
 35.4 
 
 Palladium, 
 
 56 
 
 Nitrogen, 
 
 14 
 
 Rhodium, 
 
 120 
 
 Carbon, 
 
 6 
 
 Iridium, 
 
 (?) 
 
 Sulphur, 
 
 16 
 
 Osmium, 
 
 (?) 
 
 Silenium, 
 
 40 
 
 Nickel, 
 
 29.5 
 
 Phosphorus, 
 
 16 
 
 Iron, 
 
 28 
 
 Boron, 
 
 16(?) 
 
 Lead/ 
 
 104 
 
 Iodine, 
 
 125 
 
 Tin, 
 
 59 
 
 Bromine, 
 
 (?) 
 
 Copper, 
 
 32 
 
 Silicon, 
 
 7.4 
 
 Zinc, (?) 
 
 32.2 
 
 Fluorine, 
 
 18.6 
 
 Bismuth, 
 
 71 
 
 Potassium, 
 
 39.2 
 
 Cobalt, 
 
 29.5 
 
 Sodium, 
 
 23.3 
 
 Antimony, 
 
 64.5 
 
 Lithium, 
 
 8 
 
 Arsenic, 
 
 37.6 
 
 Calcium, 
 
 20.5 
 
 Manganese, 
 
 28 
 
 Barium, 
 
 68.6 
 
 Tellurium, 
 
 32.2 
 
 Strontium, 
 
 44 
 
 Titanium, 
 
 31 
 
 Magnesium, 
 
 12 
 
 Cerium, 
 
 46 
 
 Glucinum, 
 
 18 
 
 Uranium, 
 
 217 
 
 Yttrium, 
 
 32 
 
 Columbium, 
 
 184 
 
 Allumium, 
 
 9 
 
 Tungsten, 
 
 96 
 
 Zirconium, 
 
 22.4 
 
 Cadmium, 
 
 56 
 
 Thorium, 
 
 (?) 
 
 Chromium, 
 
 28 
 
 Mercury, 
 
 101 
 
 Molybdenum, 
 
 48 
 
 Silver, 
 
 108 
 
 Vanadium, 
 
 (?) 
 
INDEX. 
 
 A. 
 
 Acid, iodic, - 
 
 157 
 
 
 
 lactic, 
 
 337 
 
 Acetate of Lead, - 
 
 317 
 
 malic, - 
 
 313 
 
 Acetates, 
 Acetous fermentation, 
 
 S17 
 
 352 
 
 manganesic, 
 molybdic, 
 
 224 
 228 
 
 Acids, definition of, - 
 General remarks on, 
 
 38 
 247 
 
 molybdous, - 
 mucous, 
 
 228 
 337 
 
 Acid, acetic, 
 
 316 
 
 muriatic, 
 
 106 
 
 animal, - 
 
 336 
 
 nitric, 
 
 99 
 
 antimonious, 
 
 221 
 
 nitrous, 
 
 93 
 
 arsenic, 
 
 223 
 
 nitro-muriatic, - 
 
 202 
 
 arsenious, 
 
 223 
 
 olific, 
 
 336 
 
 benzoic 
 
 315 
 
 oxalic, - 
 
 314 
 
 bitumous, - 
 
 315 
 
 pectic, 
 
 314 
 
 boletic, - 
 
 316 
 
 phosphoric, 
 
 152 
 
 boracic, 
 
 155 
 
 phosphorous, 
 
 151 
 
 bromic, - 
 
 159 
 
 prussic, - 
 
 136 
 
 camphoric, - 
 
 307 
 
 saccholactic, 
 
 337 
 
 carbonic, 
 
 127 
 
 silenic, - 
 
 149 
 
 chloric, 
 
 105 
 
 succinic, 
 
 316 
 
 chromic, 
 
 228 
 
 sulphuric, ^ . 
 
 143 
 
 citric, 
 
 313 
 
 sulphurous, - 
 
 142 
 
 cyanic, 
 
 135 
 
 tartaric, - 
 
 312 
 
 cyanous, , ; -^. 
 
 135 
 
 tungstic, 
 
 226 
 
 fluoric, - 
 
 307 
 
 vegetable, 
 
 312 
 
 fulminic, 
 
 289 
 
 Acidifying principle, 
 
 248 
 
 formic, - 
 
 337 
 
 Action, chemical, 
 
 4 
 
 gallic, 
 hydriotic, 
 
 314 
 157 
 
 Affinity, - 
 elective, 
 
 4 
 
 7 
 
 hydro-bromic, 
 
 159 
 
 double elective, - 
 
 9 
 
 hydro-bromous, 
 
 159 
 
 predisposing, 
 
 9 
 
 hydro-cyanic, 
 
 136 
 
 Agate, 
 
 160 
 
 hydro-fluoric, - 
 
 162 
 
 Air, atmospheric, 
 
 88 
 
 hydro-phosphoric, - 
 
 152 
 
 Alabaster, 
 
 275 
 
 hydro-sulphuric, 
 
 144 
 
 Alcohol, 
 
 309 
 
 liypo-nitrous, 
 
 97 
 
 Alembic, 
 
 21 
 
376 
 
 INDEX. 
 
 Alizarine, - 319 
 
 Albumen, vegetable, - 321 
 
 animal, - 331 
 
 Alkalies, - - 180 
 
 Alkaline metals, 179 
 
 Alkali, vegetable, - 183 
 
 volatile, 102 
 
 Alloys of metals, - - 177 
 
 Aloes, - 308 
 
 Alumium, - - 193 
 
 Alumine, sulphate of, - 279 
 
 Alum, - - 279 
 Amalgams, - - 177,196 
 Amathyst, 194, 161 
 
 Amatto, 319 
 
 Amber, 308 
 
 Ammonia, - 101 
 
 liquid, - 101 
 
 nitrate of, - 263 
 
 carbonate of, 280 
 
 phosphate of, - 285 
 
 muriate of, - 268 
 
 Analysis, chemical, 2 
 
 Animal chemistry, - 329 
 
 substances, - 330 
 
 acids, - 336 
 
 charcoal, - 124 
 
 jelly, - 331 
 
 gluten (fibrin) - 341 
 
 mucus, 335 
 
 oils and fat, - 335 
 
 albumen, - 331 
 
 coverings, - 343 
 
 Antimony, - 220 
 per-oxide, deutox- 
 ide, and protoxide 
 
 of, - - 221 
 
 Proto- chloride of 222 
 
 Anthracite coal, - 123 
 
 Apparatus, chemical, - 17 
 for dividing bodies, 17 
 for separating li- 
 quids from solids, 18 
 for the liquefaction 
 
 of solids, - 20 
 for evaporation 
 and crystaliza- 
 
 tion, - 21 
 
 for distillation, 21 
 for heating animal 
 
 substances - 23 
 
 Apparatus for compressing 
 bodies or extract- 
 ing liquids from 
 solids, 27 
 
 for collecting gas- 
 es, - - 30 
 for various chem- 
 ical purposes, 31 
 A phlogistic lamp, - 205 
 Aqua fortis, - 99 
 regia, - - 109 
 Aqueous fusion, 254 
 Arsenic, - 
 
 A rseniuretted hydrogen, 223 
 Arsenites, - 287 
 
 Arsenite of potash, - 288 
 
 of cobalt, - 288 
 
 Asafetida, - - 308 
 
 Attraction, chemical, - 2 
 Azote, - - 87 
 
 B 
 
 Balance, common, - 33 
 per cent, 
 
 portable, - 33 
 Baldwin's phosphorus - 263 
 Balloon, - 67 
 Barium, - - 188 
 protoxide of baryta, 188 
 Bases, 38 
 from the mineral king- 
 dom, - 252 
 organic, 252 
 Basic salts, - - 253 
 Bell glass, - - 30 
 Bile, <*.w 338 
 Bismuth, '""' 219 
 oxide of, - 220 
 chloride of, - 220 
 Bitter salt, - - 275 
 Black and brown coal, 123 
 Black oxide of manganese, 224 
 Blood, 332 
 Blow-pipe, - 25 
 oxy-hydrogen, 70 
 with condensed oxy- 
 
 fn and hydrogen, 72 
 277 
 
 Boiling of liquids, - 80 
 
 Bone black, - - 124 
 
INDEX. 
 
 377 
 
 Bones, 
 
 341 
 
 Chemical affinity, - 
 
 2 
 
 Borax, - 
 
 155 
 
 apparatus, - 
 
 17 
 
 Boron, - * 
 
 155 
 
 analysis, 
 
 2 
 
 Brass, ... 
 
 217 
 
 combination, 
 
 2 
 
 Brain, substance of, - 
 Bristles, - 
 
 340 
 344 
 
 composition of bodies 
 equivalents, 
 
 ,36 
 14 
 
 Bromine, 
 
 158 
 
 ingredients, 
 
 13 
 
 Butter, - 
 
 334 
 
 proportions, - 
 
 10 
 
 of antimony, 
 
 222 
 
 separation, - j 
 
 3 
 
 
 
 Chlorates, 
 
 266 
 
 C. 
 
 
 Chlorate of potash, 
 
 266 
 
 
 
 of soda, 
 
 268 
 
 Cadmium, 
 Calcium, - 
 
 227 
 
 187 
 
 hydro of ammonia, 
 Chlorides, 
 
 268 
 270 
 
 oxide of, 
 
 187 
 
 Chloride of calcium, 
 
 188 
 
 Calomel, - 
 
 198 
 
 of cobalt, 
 
 273 
 
 Camwood, 
 
 319 
 
 of copper, 217, 
 
 272 
 
 Camphor, 
 
 307 
 
 of gold, 
 
 271 
 
 Caoutchouc, - 
 
 308 
 
 of lead, - 214, 
 
 272 
 
 Carbon, - 
 
 122 
 
 of lime, 
 
 269 
 
 with chlorine, - 
 Carbonic oxide, - 
 
 138 
 125 
 
 of magnesium, - 
 of mercury, 
 
 191 
 
 198 
 
 with sulphur, - 
 
 139 
 
 of nitrogen, 
 
 109 
 
 Sulphuretof 
 
 140 
 
 of platinum, - 
 
 271 
 
 Carbonates, 
 
 280 
 
 of potassium, 
 
 184 
 
 Carbonate of ammonia, - 
 
 280 
 
 of silver, 
 
 201 
 
 of potash, - 
 
 281 
 
 of sodium, 
 
 185 
 
 of soda, 
 
 281 
 
 of strontium, 
 
 189 
 
 of magnesia, 
 
 282 
 
 of thorium, 
 
 195 
 
 of lime, 
 
 282 
 
 of tin - 216, 
 
 272 
 
 of baryta, 
 
 283 
 
 Chlorine, 
 
 103 
 
 of lead, 
 
 283 
 
 combination of, - 
 
 104" 
 
 ofiron, 
 
 284 
 
 protoxide of, - 
 
 104 
 
 of copper, - 
 
 284 
 
 per-oxide of, 
 
 105 
 
 Carburet?, 
 
 176 
 
 Chromates, 
 
 286 
 
 Carbureted hydrogen, 
 
 133 
 
 Chromate of potash, 
 
 287 
 
 sub, 
 
 130 
 
 of lead, - - 
 
 287 
 
 Cartilage, 
 
 341 
 
 of mercury, 
 
 287 
 
 Cam el ion, * *- 
 
 161 
 
 Chromium, 
 
 227 
 
 Caustic lunar, - 
 
 264 
 
 Chrysopras, 
 
 161 
 
 lye, 
 
 184 
 
 Chyle, 
 
 339 
 
 Cerium, 
 
 225 
 
 Cinnaber, 
 
 199 
 
 Chalcedon, 
 
 161 
 
 Claws, - * 
 
 343 
 
 Chalk, - 
 
 283 
 
 Coal gas, - ' - : ' 
 
 134 
 
 dampness, - 
 
 1.26 
 
 Cobalt, 
 
 220 
 
 Charcoal, vegetable, - 
 animal, - 
 
 123 
 124 
 
 Cocoa butter, 
 Cohesive attraction, - 
 
 307 
 6 
 
 Cheese, 
 
 334 
 
 Coloring matters, 
 
 319 
 
 Chemistry, definition of, - 
 
 2 
 
 Combinations in fixed pro- 
 
 
 Chemical action, 
 
 4 
 
 portions, '""M 
 
 11 
 
 32* 
 
 
 
378 
 
 INDEX. 
 
 Combinations, chemical, - 
 
 2 
 
 Element, - 
 
 4 
 
 Combustion, theory of, 
 
 52 
 
 Elements, nomenclature of, 
 
 c7 
 
 in oxygen, 
 
 53 
 
 Emerald, 
 
 194 
 
 Columbium, - 
 
 225 
 
 Epsom salts, 
 
 275 
 
 Common Resin, 
 
 308 
 
 Equivalents, - 
 
 14 
 
 Salt, - 
 
 186 
 
 Essential oils, 
 
 306 
 
 Complex affinity, - 
 
 9 
 
 Ether, 
 
 310 
 
 Congreve Rockets, 
 
 268 
 
 sulphuric, - 
 
 311 
 
 Copal, - 
 
 308 
 
 Etching on glass, 
 
 163 
 
 Copper, 
 
 216 
 
 Eudiometry, 
 
 90 
 
 combinations of, - 
 
 217 
 
 Eudiometer, Achard's, 
 
 90 
 
 proto-chloride of, 
 
 218 
 
 by detonating ox- 
 
 
 per-chloride of, - 
 
 218 
 
 ygen and hy- 
 
 
 Copperas, 
 
 144 
 
 drogen gas, 
 
 91 
 
 Corrosive sublimate, 
 
 198 
 
 Gay Lussac's, 
 
 92 
 
 Cream, 
 
 334 
 
 Evaporation, 
 
 -1 
 
 of tartar, - 
 
 312 
 
 apparatus for, 
 
 21 
 
 Cruor of the blood, 
 
 332 
 
 Extinguishing of fire, 
 
 58 
 
 Cryophorus, 
 
 82 
 
 Extract, vegetable, 
 
 320 
 
 Crystalography, 
 
 254 
 
 
 
 Crystal mountain, 
 
 313 
 
 F. 
 
 
 Cyanites, 
 
 288 
 
 
 
 Cyanuret of mercury, 
 Cyanogen, 
 
 135 
 134 
 
 Fats, animal, 
 Feathers, 
 
 335 
 344 
 
 with oxygen, 
 
 135 
 
 Fermentation, 
 
 352 
 
 with hydrogen, 
 
 135 
 
 acetous, 
 putrid, 
 
 353 
 355 
 
 D. 
 
 
 vinous, - 
 
 352 
 
 
 
 Fermentous principle, 
 
 320 
 
 Diamond, 
 
 122 
 
 Fernambucco wood, - 
 
 319 
 
 Decrepitation, 
 
 254 
 
 Fibrin, 
 
 341 
 
 Decomposition, 
 
 3 
 
 Fibre, woody, 
 
 304 
 
 spontaneous, 
 
 352 
 
 Fire-damp, 
 
 130 
 
 Definite proportions, - 
 
 11 
 
 Fixed air, 
 
 126 
 
 volumes, - 
 
 76 
 
 Fixed. oils, 
 
 307 
 
 Desoxidation, - 
 Deliquescence, - 
 
 59 
 254 
 
 vegetable alkalies, 
 proportions and ratios, 
 
 302 
 11 
 
 Difference between organic 
 
 
 Flint, - ;;;i*. 
 
 161 
 
 and inorganic matter, 
 
 300 
 
 Fluorine, 
 
 162 
 
 Distillation of water, 
 
 83 
 
 other combinations of, 163 
 
 Dragons' blood, 
 
 308 
 
 Flowers of sulphur, 
 
 141 
 
 Dregs, - 6 ^-..'. :-,',; 
 
 320 
 
 zinc, 
 
 219 
 
 
 
 Fluoride of calcium, 
 
 162 
 
 E. 
 
 
 Fluorides, 
 
 176 
 
 
 
 Fluor, 
 
 160 
 
 Earthy metals, 
 
 190 
 
 Flux, - '*'-, 
 
 179 
 
 Efflorescence, 
 
 254 
 
 Frost bearer, , ~~j?\ 
 
 82 
 
 Elective affinity, - 
 
 7 
 
 Fulminates, - 
 
 288 
 
 double, 
 
 9 
 
 Fulminating powder, 
 
 261 
 
 Electricity, galvanic, 
 
 250 
 
 Furnace, 
 
 23 
 
 Electro-chemical theory, 
 
 14 Fustic, - 
 
 319 
 
INDEX 
 
 379 
 
 G. 
 
 Horn lead, - - 214 
 
 
 silver, - - 201 
 
 Galena, - -. 214 
 
 Horns, - - 344 
 
 Galvanic electricity, - 40 
 
 Hydrates, - - 249 
 
 Gamboge, - 308 
 
 lydrate of potash, - 183 
 
 Gas, Oxygen, 
 hydrogen, 
 
 lydro-chlorate of ammonia, 268 
 Jydro-acids, - . - 249 
 
 carbonic acid, - 127 
 
 lydrogen, - 59 
 
 muriatic acid, "- 106 
 light, 
 
 lydrogen, properties of, 
 mode of obtaining, 64 
 
 olifiant, - - 133 
 
 carbureted, - 133 
 
 nitrogen, - - 87 
 
 sulphureted, 147 
 
 Gases, combina'n by volume, 76 
 
 sub-carbureted, 130 
 
 Gastric juice, 
 
 combination with 
 
 Gelatine, 
 
 oxygen, - 73 
 
 Germination of seeds, - 351 
 
 deutoxide of 8G 
 
 Gilding, - 196 
 
 mixture with oxy- 
 
 Glass makers' soap, 
 
 gen, *Jg 67 
 
 Glass, - 
 
 gun, - 
 
 Glimmer, - 
 
 application of 66 
 
 Glucina, - 192 
 
 -ivrfrous state, 
 
 Glucinum, 
 
 rlypo-nitrous aoid, - 97 
 
 Glue, animal, - 
 
 
 Gluten, - - 321 
 
 I. 
 
 Gold, - 
 
 
 combinations of 
 
 Ice, 77 
 
 Granite, 
 Graphit, - - 123 
 
 Immediate ingredients of an- 
 unals, - 329 
 
 Gravitation of integrant mole- 
 
 of vegetables, 302 
 
 cules, - - 259 
 
 Ink, indelible or marking, 265 
 
 Green vitriol, - 278 
 Gum, - 
 
 sympathetic, 
 writing, 
 
 ammonia, 
 
 India rubber, - 
 
 elastic, - 308 
 
 Indigo, - 
 
 Gun metal, 
 
 Inflammable air, - 13j 
 
 powder, 
 
 gas, - 
 
 properties Of, 
 Gypsum, - - 272 
 
 Ingredients, 
 Ingredients of the animal 
 body, - 320 
 
 H. 
 
 Hair, - - - 344 
 
 Hare's blow pipe, 
 Hartshorn, 
 spirits of, - 
 
 Inorganized bodies} 
 Inorganic elements of plants, 3 
 Instantaneous light matches, 267 
 Integrant moleciMes, - 257 
 Iodide of quicksilver, - 
 Iodine, properties of, - 156 
 
 Heat, 
 
 with carbon, - 
 
 effects of, 
 promoting chemical affin- 
 
 with hydrogen, - 157 
 with oxygen, - 
 
 ity j 
 
 Iridium, - - - 207 
 
 Heavy spar, - 
 
 Iron, - - - 208 
 
 Hoofs, - ' 34 
 
 
380 
 
 INDEX. 
 
 Iron, combination of, 
 with carbon, 
 meteoric, 
 protoxide of, 
 per-oxide of, - 
 proto-chloride of, 
 per-chloride of, 
 sulphuret of, 
 
 Juice of grapes, 
 
 Kelp, - 
 Kings' water, 
 
 K. 
 
 L. 
 
 208 
 211 
 208 
 208 
 209 
 210 
 210 
 211 
 302 
 
 156 
 
 202 
 
 Lamp, - 24 
 furnace, 25 
 safety, - - 131 
 Lac lake, - - 319 
 Lard, - - -337 
 Lead, - - - 212 
 combination with oxy- 
 gen, - 213 
 chloride of, - ' 214 
 Lees, - - - 320 
 Lehigh coal, - - 123 
 Levity of hydrogen gas, - 63 
 Life and death of animals, 800 
 Lime, - - 187 
 stone, - 283 
 Ligaments, - - 343 
 Light, carbureted hydrogen, 130 
 Liquid ammonia, - - 101 
 sulphuric acid, - 144 
 muriatic acid, - 108 
 nitric acid, - 99 
 Liquids employed in the pro- 
 cess of digestion, 338 
 Litmus, - - - 319 
 Litharge, - 214 
 Lithium, - - 186 
 Lithia, 187 
 Loaf sugar, '. - 306 
 Lunar caustic, 264 
 Lutes, - ;".. - ..V - 35 
 Lye, caustic, - ;. '. . 184 
 
 M. 
 
 Malates, 
 
 313 
 
 Magnesia, - 191 
 
 Magnesium, - 190 
 
 Marble, - - - 283 
 
 Marrow, - - 342 
 
 Manganese, - - 224 
 
 oxide of, - 224 
 
 chloride of, - 224 
 
 Massicot, - 214 
 
 Membranes, - - 342 
 
 Mercurial ore, 195 
 
 Mercury, - - 195 
 
 properties of, 195 
 
 combination with 
 
 oxygen, - 196 
 
 protoxide of, 197 
 
 per-oxide of, - 197 
 
 with chlorine, 197 
 
 with sulphur, - 199 
 
 Metals, classification of, 179 
 
 alloys of, - - 177 
 
 preliminary remarks 
 
 on, - 175 
 general properties of, 174 
 reduction of, - 178 
 refining, - 177 
 nomenclature of, - 175 
 combining with oxy- 
 gen, - 175 
 other combinations of, 176 
 soldering of, - 177 
 Meteoric iron, - - 209 
 Microcosmic salt, - - 285 
 Milk, 333 
 sugar of, - - 335 
 Mineralizers, - 178 
 Mixtures of nitrogen and oxy- 
 gen, - 9 
 of hydrogen and oxy- 
 gen, - 67 
 Molasses, - - - 306 
 Molybdenum, 228 
 Mucus, animal, - - 335 
 Muscles, - 342 
 Muriates, - - 279 
 Myrrh, - 308 
 
 N. 
 
 Native metals, . 178 
 
 Nerves, substance of, - 340 
 
 Neutralization, - 6 
 
INDEX 
 
 381 
 
 Neutral animal substances, 83 
 unsalifiable vegetable 
 
 substances, 30 
 
 Neutral salts, - 25 
 
 Nickel, - - 20 
 
 oxide of, 20 
 
 Nitrates, - - - 25 
 
 Nitrate of potash, - 26 
 
 of sod a, - 26 
 
 of ammonia, - 26 
 
 of lime, - - 26; 
 
 of lead, 26i 
 
 of copper, - - 266 
 
 of mercury, - 26 
 
 of silver, - - 26 
 
 Nitre, properties of, - 26( 
 
 Nitrogen, - 
 
 combination with 
 
 oxygen, - 92 
 
 mixture of, - 88 
 
 protoxide of, - 91 
 
 deutoxide of, 95 
 
 with hydrogen, - 10 
 
 Nomenclature of elements, 37 
 
 of acids, 
 
 of oxides, 51 
 
 of salts, 253 
 
 Non-metallic elements, 122 
 
 Nooth's apparatus, - - 129 
 
 O. 
 
 Oil of almonds, - 307 
 
 of vitriol, - - 143 
 
 olive, - 307 
 
 Olefiant gas, - - 133 
 
 application of, 133 
 
 Organic chemistry, - 300 
 
 Organized bodies, - 300 
 
 Organs, ' - - 301 
 
 Ores, - - 178 
 
 Osmazome, - 340 
 
 Osmium, - 207 
 
 Oxalates, - - 314 
 
 Oxides, definition of, - 38 
 
 nomenclature of, - 51 
 
 Oxidation, - 175 
 
 Oxygen, properties of, - 50 
 
 mode of obtaining, 50 
 
 combination of, 51 
 
 combustion of, - 53 
 
 Oxygenation of bodies, - 61 
 
 Oxygenized water, - 86 
 
 P. 
 
 Palladium, - - 206 
 
 Pearlash, - . 133 
 
 Phenomena attending acetous 
 
 fermentation, 355 
 attending vinous 
 
 fermentation, 353 
 attending putre- 
 faction, 4$> 355 
 Phlogiston of the ancients, 52 
 Phosphates, . 284 
 
 Phosphate of ammonia, 285 
 
 of soda, - 285 
 
 of lime, - 286 
 
 Phosphorus, - 149 
 
 properties of, 150 
 with oxygen, 151 
 with hydrogen, 152 
 other combina- 
 tions of, - 154 
 Phosphureted hydrogen, 153 
 Plants, nature of, - 48 - 300 
 Plaster stone, - 275 
 
 of Paris, - 275 
 
 Platinum, - 204 
 
 sponge, - - 205 
 
 lumbago, - 123 
 
 D neumatic tub, - 30 
 
 Potash, - 183 
 
 hydrate of, - 183 
 
 3 otassium, - 180 
 
 mode of obtaining, 181 
 properties of,y^ 182 
 combinations with 
 
 oxygen, - 183 
 
 chloride of, - 184 
 
 Mmitive form of crystals, 255 
 >oducts of vegetables, 302 
 
 'roportions, & - 11 
 
 ^rocess of nutrition necessa- 
 ry to life, - 351 
 'rocess of putrefaction, 3J>5 
 
 'russian blue, 318 
 
 russicacid, - 136, 318 
 
 umice, - - 161 
 
 utrefaction with free access 
 
 of air, - 356 
 
382 
 
 INDEX. 
 
 Putrefaction with little or no 
 
 
 Saturation, - - 8 
 
 accessof air, 
 
 357 
 
 Scale of equivalents, - 374 
 
 Putrid fermentation of vege- 
 tables, 
 
 355 
 
 Scales, - - -343 
 Secondary form of crystals, 255 
 
 Pyrites, 
 
 211 
 
 Selenites, - 275 
 
 
 
 Selenium, 149 
 
 Q. 
 
 
 Selieneted hydrogen, 149 
 
 
 
 Serum, - - 332 
 
 Quar'z, ... 
 
 161 
 
 Sheet iron tinning, - 178 
 
 Quaternary combinations, 
 
 247 
 
 Silicious earth, - - 161 
 
 Quicksilver, - 
 
 195 
 
 Silicides, - 176 
 
 
 
 Silicon, - - - 159 
 
 R. 
 
 
 Silex, - - 160 
 
 
 
 Silk, - - 344 
 
 Raw sugar, 
 
 306 
 
 Silver, 
 
 Realgar, - 
 
 224 
 
 combinations of, - 200 
 
 Receiver, 
 
 22 
 
 oxide of, - 201 
 
 Red oxide of copper, 
 
 217 
 
 sulphuretof, - 
 
 Reduction of metals, - 
 
 178 
 
 Silvering of looking-glasses, 196 
 
 Refining of sugar, 
 Remote ingredients of plants. 
 
 306 
 302 
 
 Simple bodies, - - 37 
 Skin, - - 343 
 
 Resins, - 
 
 303 
 
 Slaking lime, - - 187 
 
 Respiration, - 
 
 330 
 
 Smalts, - - 220 
 
 Rete mucosum, - 
 
 343 
 
 Smelting ores, - - 179 
 
 Retort, 
 
 22 
 
 Soap, - - 307 
 
 Rhubarb, S 
 
 319 
 
 Soda, - - - 185 
 
 Rhodium, 
 
 207 
 
 Sodium, 185 
 
 Rock or mountain crystal, 
 
 161 
 
 with oxygen, - 185 
 
 Roll-brimstone, 
 
 142 
 
 protoxide and per-ox- 
 
 Roasting of metals, . - 
 
 179 
 
 ide of, - 185 
 
 Rotten stone, - 
 
 161 
 
 chloride of, - 186 
 
 Rust of iron, 
 
 176 
 
 Solution, - 8 
 
 
 
 Spar, - - - 162 
 
 S. 
 
 
 Specific gravity, mode of de- 
 
 
 * * - 
 
 termining, - 34 
 
 Safety lamp, 
 
 131 
 
 Speculum metal, - 217 
 
 Safflower, 
 
 319 
 
 Spermaceti, - - 336 
 
 Saffron, 
 
 319 
 
 Spirit of hartshorn, - 101 
 
 Sal-ammoniac, 
 
 101 
 
 Spiritus cornu cervi, - 331 
 
 Salifiable bases, 
 
 252 
 
 Spirituous liquors, - 309 
 
 vegetable bases, 
 Saliva, ... 
 
 311 
 338 
 
 Sponge, platinum, - -205 
 Soldering of metals, - 177 
 
 Saltpetre, uses of, 
 
 261 
 
 Sorb or service tree, - 313 
 
 Salts, definition of, 
 
 249 
 
 Sour salts, - 253 
 
 of hartshorn, - 
 
 280 
 
 Steam, - 84 
 
 common: table, 
 
 186 
 
 principal properties of, 84 
 
 smelling, 
 
 280 
 
 engine, - 360 
 
 Sanders' wood, - 
 
 309 
 
 Steel, - - - 211 
 
 Sand, 
 
 161 
 
 Strontia, - - 189 
 
 Sandarach, 
 
 308 
 
 water, - - 189 
 
 Sapphire, 
 
 194 
 
 Strontium. - - 189 
 
INDEX. 
 
 383 
 
 Succinates, 
 
 316 
 
 Tendons, - . 342 
 
 Sugar, - 
 
 305 
 
 Thoria, - - . 195 
 
 manufactory of, . - 
 
 306 
 
 Thorium, - 195 
 
 of lead, - 
 
 317 
 
 chloride of ( - 195 
 
 of milk, 
 Sulphates, 
 Sulphate' of potash, 
 
 333 
 273 
 274 
 
 Thornberry, black, & 319 
 Tin, - - l . 214 
 salt, - 272 
 
 of soda, 
 
 274 
 
 with oxygen, 215 
 
 of lime, -' 
 of magnesia, 
 
 275 
 275 
 
 chloride of, - 216 
 Titanium, - - 225 
 
 of mercury, 
 
 276 
 
 Tombac, - 217 
 
 of silver, 
 
 277 
 
 Topaz, - - -194 
 
 of copper, 
 
 277 
 
 Tripoli, - ; . 161 
 
 of iron, 
 
 278 
 
 Tungsten, - - 226 
 
 of baryta, 
 
 278 
 
 Turf, . 123 
 
 of ammonia, 
 
 278 
 
 Tumeric, - 319 
 
 ofalumine, 
 
 279 
 
 Turpentine, - 308 
 
 Sulphides, 
 
 176 
 
 - 
 
 Sulphur, 
 
 141 
 
 U. 
 
 properties of, - 
 combinations of, - 
 with oxygen, - 
 Sulphuret of silver, 
 
 nf IpaH 
 
 142 
 142 
 142 
 
 201 
 914. 
 
 Ultimate principles of plants, 303 
 of animals, 330 
 Undetermined vegetable sub- 
 stances, t - 318 
 
 Ol lead, 
 
 of iron, - 
 
 201,4 
 
 211 
 
 Unsaleable vegetable sub- 
 
 of palladium, 
 of arsenic, 
 of tin, 
 
 207 
 224 
 216 
 
 stances, - 303 
 Uranium, - - 226 
 oxide of, \- 226 
 
 of antimony, 
 
 222 
 
 
 of copper, - 
 
 218 
 
 
 
 of carbon, 
 
 139 
 
 Vanadium, 228 
 
 of strontium, 
 of mercury, 
 
 189 
 199 
 
 Vapor, refrigerating influ- 
 ence of, V^ 
 
 Sulphureted hydrogen, - 
 Sulphuric acid, mode of pre- 
 
 148 
 
 Vegetable chemistry, - 300 
 acids, - 303,312 
 
 paring, 
 
 145 
 
 alkali, - - 183 
 
 Synthesis, 
 
 2 
 
 extract, 
 composition of, 303 
 
 IA. ^0R* 01 o 
 
 T. 
 
 
 salt, e 
 
 
 
 substances of an 
 
 Table salt, 
 
 186 
 
 undetermined na- 
 
 Tallow, 
 
 335 
 
 ture, 
 
 Tan, 
 
 314 
 
 Venice-sumac, f - 319 
 
 Tartar, 
 
 313 
 
 Vermilion, - J 199 
 
 cream of, - 
 
 312 
 
 Vinous fermentation, 352 
 
 Tartrate of potash, * 
 
 313 
 
 phenomena accompa- 
 
 Teeth, 
 
 341 
 
 nying, 
 
 enamel of 
 Tellurium, 
 Temperature changed by 
 chemical action, - 
 
 342 
 225 
 
 4 
 
 Virgin quicksilver, 195 
 Vital principle, 301 
 Vitriol, oil of, C 
 green, 278, 144 
 
384 
 
 INDEX. 
 
 
 
 
 
 Vitriol, blue, - , .*- , ' 
 
 277 
 
 White oxide of phosphorus, 
 
 151 
 
 Volatile alkali, 
 
 102 
 
 Woad, - 
 
 319 
 
 Volumes of gases, 
 
 76 
 
 Wollaston's theory, - 
 
 258 
 
 
 
 Wolfram, - 
 
 226 
 
 W. 
 
 
 Wool, - 
 
 344 
 
 
 
 Woolf s apparatus, 
 
 107 
 
 Water, - 
 
 73 
 
 
 
 composition of, - 
 
 75 
 
 Y. 
 
 
 properties of, 
 
 76 
 
 
 
 of erystalization, 
 
 254 
 
 Yttrium, - 
 
 193 
 
 expansion in freezing, 
 boiling of, 
 
 77 
 81 
 
 oxide of, 
 Ytterby, - 
 
 193 
 193 
 
 baryta, 
 
 188 
 
 f- 
 
 
 strontia, 
 
 189 
 
 Z. 
 
 
 oxygenized, 
 rain, pump, and river, 
 Jpurity of, - 
 gilding, 
 Watery animal substances, 
 unsaJifiable vegetable 
 /substances, 
 
 86 
 78 
 85 
 196 
 330 
 
 306 
 
 Zaffre, 
 Zinc, - 
 oxide of, 
 flowers of, 
 carbonate of, - 
 chloride of, 
 
 319 
 218 
 219 
 219 
 219 
 219 
 
 Wax, - 
 
 309 
 
 Zircon, 
 
 194 
 
 Weld 
 
 319 
 
 Zirconia, 
 
 194 
 
 Whale oil, - 
 
 336 
 
 Zirconium, 
 
 194 
 
 Wheat, - X - 
 
 321 
 
 
 

 
 
 
^ 
 

 
 
 

 
 
 Ik. 
 
 
.