CATECHISM 
 
 OK 
 
 rrxiCULTUUAL CIL..MISTRY 
 
 G E O L O G 
 
 UC-NRLF 
 
 En'ihind, and \aUior 
 I Geulogy, ' 
 
 AN INTIJODI "TION, 
 
 JOHN PITKIN lOKTON, 
 
 or Fartniti^on, Comieclicut. 
 
 rUlM Till: 13RJI1TI[ UNUI.ISH ITDITION, 
 
 Will. N.Mi-s and AddUioils by llie AuUior, prcpai'ed expressly for 
 this Edition. 
 
 ALBANY: 
 
 KRASTUS H. PEASE. 
 
 1 8 ■; 'i . 
 
 £i 
 
THE LIBRARY 
 
 OF 
 
 THE UNIVERSITY 
 
 OF CALIFORNIA 
 
 PRESENTED BY 
 
 PROF. CHARLES A. KOFOID AND 
 
 MRS. PRUDENCE W. KOFOID 
 
 LIBRMt 
 
^^ 
 
RECOMMENDATIONS. 
 
 From Hon. Saml. Young, Secretary of State and Super- 
 iniendent of Common Schools of the State of New- 
 York ; 
 
 I have carefully examined the Catechism of Professor 
 Johnston, on Agriculture. It is the only scientific work on 
 that subject I have ever seen, which by its shortness and 
 simplicity is adapted to the capacity of children ; and 
 which, on being illustrated by cheap and simple experi- 
 ments, as he recommends, cannot fail to make a lasting 
 impression on the juvenile mind. 
 
 It gives the analysis of different plants, of animals and 
 of soils, exhibiting the organic and inorganic substances of 
 which they are composed, and teaching the important 
 truths that vegetables drrive a part of their nourishment 
 from the air and the remainder from the earth ; that diffe- 
 rent vegetables require diflerent kimis of food and in va- 
 riable quantities ; that the soil may be destitute of nutri- 
 tion for one kind of plant and not for another ; ami the 
 means are explained of supplying to an exhausted or 
 meagre soil its deficiencies. It also gives the rationale of 
 the dairy and the fattening of animals. 
 
 This little work is the basis of both agricultural art and 
 science. A knowledge of its principles is within the com- 
 prehension of every child of twelve years old ; and if its 
 truths were impressed on the minds of the young, a foun- 
 dation would be laid for a vast improvement in that most 
 important occupation which feeds and clothes the human 
 race. Instead of conjecture, and hazard, and doubt and 
 experiment, as heretofore, a knowledge of the composition 
 of soils, the food of plants and the processes of nature in the 
 culture and growth of crops, would elevate agriculture to a 
 conspicuous rank among the exact sciences. 
 
 I hope that parents will be willing to introduce this brief 
 catechism into the Common Schools of this State. 
 
 S. YOUNG. 
 Albany, 24th January, 1845. 
 
Yale College, Laboratory, ) 
 ^ew■Haven, Ct., 20th Jany. ISib. S 
 
 I have read with great pleasure and profit the condensed 
 little Agricultural Catechism of Prof. James F. W. John- 
 ston of Scotland. Like every production of his pen, it is 
 characterized by a sound, practical good sense, vphich adds 
 double value to his scientific labors, rendering them availa- 
 ble to the very class for whom they are more es; ccially de- 
 signed — practical farmers. 
 
 I learned with pleasure from Prof. Johnston, that Mr. 
 John P. Norton was about to edit, with an introduction, his 
 Agricultural Catechism. This American edition should be 
 in every village school in the land , as being within the com- 
 prehension of all intelligent children : and it cannot indeed 
 be too highly recommended to the attention of all classes of 
 teachers, as the best synopsis yet made of the valuable facts 
 and principles which have been established in the important 
 science of agriculture. 
 
 B. SILLIMAN, Jr. 
 
 I consider "J. F. W. Johnston's Catechism of Agricul- 
 tural Chemistry and Geology," to be extremely well adapt- 
 ed to the use of schools., and that it ought to be introduced 
 as a text-book into all our rural districts where farming is 
 the principal employment of the population. The time has 
 come when Agriculture is to be taught as a science as well 
 as cultivated as an art, and a little book like this sheds 
 more light on the nature of soils, the elementary principles 
 of plants, and the food necessary for their growth and ma- 
 turity, in a smallcompass, tlianany other publicalion I have 
 ever seen. The youthful mind can easily be made to com- 
 prehend the principles it teaches, and we are wanting to our 
 own and the great interests of our country, if at this time 
 we do not do all in our power to create a taste and diffuse a 
 knowledge of so important a pursuit. 
 
 J. P. BEEKMAN, 
 late Prest. o/N. Y. S. A. Society. 
 
 Kinderhook, Jan. 22, 1845, 
 
Having examined Professor Johnston's Catechism on 
 Agricultural Chemistry and Geology,! most cordially unite 
 in the recommendation of the work. Its introduction into 
 our Common Schools, will form a new era in the education 
 of our children. The time has arrived in which every pro- 
 per effort should be made to give such an education to the 
 rising generation as will prepare them rightly to appreciate, 
 as well as successfully to follow, the pursuits of agriculture, 
 for which most of them are designed. It will give me great 
 pleasure to do all in my power to disseminate this little 
 work, which I doubt not will produce the most happy effects 
 throughout our country. 
 
 BENJ, P. JOHNSON, 
 President N. ¥. State J^ricultural Society. 
 
 Rome, Jan. 23d, 1845. 
 
 The apparatus necessary to perform the experiments 
 mentioned in this Catechism, may be had complete of Mr. 
 George Dexter, Albany, for $3.50 ; or a receiver and retort 
 with stand for from $1.25 to $2.00. 
 
CATECHISM 
 
 OF 
 
 AGRICULTUrvAL CHEMISTRY 
 
 AND 
 
 GEOLOGY. 
 
 BT 
 
 JAMES F. W. JOHNSTON, M.A., FR.SS.L.&E. 
 
 Honorary Member of the Royal Agricultural Society of England, and AuUlor 
 of " Lectures on Agricultural Chemistry and Geology." 
 
 WITH 
 
 AN INTRODUCTION, 
 
 JOHN PITKIN NORTON, 
 Of Farmington, Connecticut. 
 
 FROM THE EIGHTH ENGLISH EDITION, 
 
 With Notes and Additions by the Author, prepared expressly (or 
 this Edition. 
 
 ALBANY: 
 
 ERASTUS H. PEASE. 
 
 1846. 
 
Edtered according to Act of Coni^resg, in the year 1845, by 
 
 ESASTUS H. PEA9E, 
 
 ia the Clerk's Office of the Nor±em District of New-Tork. 
 
INTKODUCTION 
 
 TO THE 
 
 AMERICAN EDITION. 
 
 
 In introducing this little work to the notice of the 
 American public, I am encouraged by the hope that 
 a conviction as to the importance of the new know- 
 ledge of which it treats, already fixed in many 
 minds, will soon become universal. Agriculture, 
 the art in which nine-tenths of the capital of civil- 
 ized nations is embarked, upon which all depend 
 for subsistence, is rising towards its proper rank as 
 a science. We look forward to the time when it 
 will be generally conducted upon fixed and scienti- 
 fic principles, dependent upon immutabb laws. 
 Obstacles may retard, but cannot permanentl)- ar- 
 rest its progress, and those who receive the light 
 that we now possess, and keep pace with our in- 
 creasing knowledge, will surelj' reap the benefit 
 which always results from the application of en- 
 lightened skill; while those who linger behind 
 must be content to grope on in blind uncertainty, as 
 our forefathers have done. 
 
 fca'i/j onoo 
 
4 INTKODCCTION. 
 
 I am, however, aware that we can scarcely expect 
 the present generation of farmers, engrossed with 
 the cares and business of life, with their prejudices 
 and habits of thought strengthened by years, gene- 
 rally to enter this new field, and to commence with 
 energy the study of what seems to them a formida- 
 ble science. But may we not with confidence hope 
 that they will cheerfully place the means of instruc- 
 tion within the reach of their children? 
 
 Scientific terms, and strict modes of reasoning, 
 are already becoming common in the daily inter- 
 course of agriculturists. In the next generation 
 this will become almost universal, and the farmer 
 who now neglects the instruction of his children in 
 elementary scientific knowledge, may with reason 
 apprehend that more skillful and better taught cul- 
 tivators, will hereafter thrust them aside, and oc- 
 cupy the places which they might have filled. 
 
 That children may be early and thoroughly 
 taught this elementary science, I have seen most 
 satisfactorily proved. At the late show of the High- 
 land and Agricultural Society, at Glasgow, five 
 bo)-s were present from the Lame School in Ire- 
 land. They were from twelve to sixteen years of 
 age, and were sons of small tenant farmers. In the 
 course of a searching public examination, they 
 evinced a knowledge of elementary chemistry, as 
 
INTRODUCTION. 5 
 
 applied to agriculture, that was truly surprising; 
 and not only were they conversant with this branch 
 of chemistry, but with practical farming also. The 
 expressions of delight and satisfaction at the close 
 of the examination, were unanimous. These boys 
 are taught, it must be noticed, without neglecting 
 their other studies, as only two or three hours a 
 week are devoted to this branch of instruction. 
 When their course of study is complete, they are 
 either competent to take charge of their own farms, 
 or to act as land stewards or agents for others. 
 
 This system of instruction is about to be more or 
 less perfectly carried out in three thousand of the 
 Irish schools, and in Scotland a great change is 
 rapidly taking place. The schoolmasters, at their 
 aunual convention a few weeks since, decided unan- 
 imously to introduce a system somewhat resembling 
 the Irish, into all the Scottish schools. The zeal, 
 both of the masters and the people of Scotland, is 
 enthusiastic. What I have witnessed of it in va- 
 rious parts of this country, has made me desirous 
 that the subject should be brought under the consi- 
 deration of my own countrymen. 
 
 It seems to me that our circumstances, at least 
 in the northeastern and northern states, are pecu- 
 liarly favorable. We have in almost every village 
 an academy, or a school higher than the common 
 
6 INTRODUCTION. 
 
 district schools, taught generally by graduates of 
 our colleges. How easy for these teachers to de- 
 vote two hours of their pupils' time in each week, 
 to the study of such a work as this Catechism I A 
 few shillings will supply all the apparatus necessa- 
 ry for the simple experiments it describes, and these 
 experiments will indelibly impress upon the youth- 
 ful mind, the nature and properties of carbon, oxy- 
 gen, nitrogen, and those other bodies which form 
 our plants, our food, ourselves, and the earth upon 
 which we live. 
 
 The district schools, also, might be made the 
 means of conveying similar information. Where 
 the community is interested, the teachers, I am con- 
 fident, will be found ready cheerfully to do their 
 part. I have met the parish and other schoolmas- 
 ters in various parts of Scotland ; they vie with 
 each other in their desire to attain and impart this 
 new knowledge. My own fellow-citizens, I am 
 sure, will not be less eager in their country's ser- 
 yice. 
 
 An attempt to recommend this Catechism by any 
 praise of mine, might seem presumptuous. The 
 wide and extensive reputation of its author — com- 
 bining in an eminent degree, theoretical with prac- 
 tical knowledge, and penetration with prudent cau- 
 tion, together with the fact that this little work, and 
 
INTKODTTCTION. 7 
 
 his Elements of Agricnltural Chemistry and Geo- 
 logy, are the text-books in all the Irish as well as 
 the Scottish schools, will be a sufficient guarantee 
 of its merit. I can therefore only express my ear- 
 nest desire that it may be the herald of agricultu- 
 ral school instruction in the United States. I trust 
 that it may be attentively perused by my country- 
 men generally, old as well as young; for I am sa- 
 tisfied that many will feel disposed, after reading 
 it, to follow the example of an Irish gentleman, 
 who thanked the author for having given him a 
 •profession. 
 
 The present edition is reprinted from the eighth 
 English edition, with manuscript alterations and 
 Additions by the author. 
 
 JOHN PITKIN NORTON, 
 
 Farmington, Conn. 
 
 Edinburgh, Nov., 1S44. 
 
TO THE SCHOOLMASTERS AND TEACHERS OF 
 GREAT BRITAIN AND IRELAND. 
 
 Gentlemen, 
 
 Having written the present little work 
 with a view to the more speedy improvement of the agri- 
 culttire of our common country, I take the liberty of dedi- 
 cating it to you. No class of men possesses in so high a 
 degree the power of promoting an object so important to 
 aU. I am anxious, therefore, to secure not only your 
 willing support, but, if possible, your cordial co-operation 
 also. 
 
 The land from which our crops are raised must be ren- 
 dered more productive, if food is to be grown at home for 
 our increasing population. But the produce can be largely 
 increased only by the application of increased knowledge 
 to the culture of the soil; — and it is the rising generation 
 now under your care, which must possess and apply this 
 knowledge. You can scarcely render a higher service to 
 your country, therefore, than by imparting, along with 
 your other instructions, the rudiments of that kind of know- 
 ledge on which its prosperity must so greatly depend. 
 Few of your pupils will then escape from your hands so 
 early as not to have already learned what may enable 
 them on some spot or other in after life, " to make two 
 blades of grass to grow where only one grew before." 
 I have the honor to be. 
 Gentlemen, 
 
 Your obedient servant, 
 
 JAMES F. W. JOHNSTON. 
 
 EoiNBtJKGH, 
 
 1st February, 1844. 
 
ADVERTISEMENT. 
 
 The Author believes that the country teacher who may 
 introduce this little Catechism into his school, will find no 
 difficulty in making his elder classes understand the differ- 
 ent subjects which are successively adverted to. It will 
 not be necessary to make them commit the very words of 
 each answer to memory. They should be taught rather 
 to make themselves masters of the matter of each, so as 
 to be able to express the sense of the answers in words of 
 their own. 
 
 On first going over the questions, the pupil's attention 
 may be confined to such only as the teacher may consider 
 most important or most applicable to the practice of the 
 neighborhood in which he lives. The other questions 
 will be taken up on a second perusal, and an occasional 
 general catechising upon the whole book will fi.\ the mat- 
 ters treated of more firmly in the minds of his scholars. 
 
 The teacher himself will find further information in the 
 Author's Elements and pnhlished Lectures on Agricultural 
 Chemistry and Geology; and a set of apparatus especially 
 prepared for this Catechism, may be obtained from Rich- 
 ard GriiBn & Co., of Glasgow, at a cost of thirty shillings. 
 
CATECHISM 
 
 OK 
 
 AGRICULTURAL CHEMISTRY AXD GEOLOGY. 
 
 Q. What is agriculture'! 
 
 A. Agriculture is the art of cultivating the soil. 
 Q. IF hat is the object of the farmer in cultivating the 
 soil ? 
 
 A. The object of the farmer in cultivating the soil is, 
 to raise the largest crops at the smallest cost, and with 
 the least injury to the land. 
 
 Q. What ought the farmer especially to know, in order 
 that he may attain this object ? 
 
 A. The farmer ought especially to know ihe nature of 
 the crops he raises, of the land on which they grow, and 
 of the manures which he applies to the land. 
 
 I. — OF THE NATURE OF THE CROPS HE RAISES. 
 
 Q. Of what parts do all vegetable substances consist ? 
 
 A. All vegetable substances consist ol two parts, one 
 which burns away in the fire, called the organic part, 
 and one which does not burn away, called the inorganic 
 part. 
 
 Here Ihe teacher will burn a bit of straw or wooil in the 
 candle, (fi^. 1,) anil show that one part burns away, and 
 that another very small part — the ash — doesnot burn away 
 
12 
 
 CATECHISM OF AGRICULTtTRAL 
 
 Q. Which of these livo parts is 
 the greater in quantity ? 
 A. In all veg-etable substances, 
 the organic part is very much the 
 greater. It forms from 90 to 99 
 out of every 100 lbs. of their 
 weight. 
 
 Q. Of what elementary bodies 
 does the organic part of 
 plants consist ? 
 A. The organic part of plants 
 consists of four elementary bodies, known by the names 
 of carbon, hydregen, oxygen and nitrogen. 
 Q. What is carbon. 
 
 A. Carbon is a solid substance, usually of black 
 colour, which has no taste or smell, and burns more or less 
 readily in the fire. Wood-charcoal, lamp-black, coke, 
 black-lead, and the diamond, are varieties of carbon. 
 
 The teacher will here exhibit a piece of charcoal and 
 show how it burns in the fire, or in the flame of a can- 
 iDe. He may also draw their attention to Uie remarkable 
 difference in appearance between cliarcoal and the dia- 
 mond, though essentially the same. 
 
 Q. What is hydrogen ? 
 
 A. Hydrogen is a kind of air or gas which burns in 
 the air as coal gas does, but in which a candle will not 
 burn, nor an animal live, and which, after being mixed 
 with common air, explodes when it is brought near the 
 flame of a candle. It is also the lightest of all known 
 stibstances 
 
CHEMISTRY AND GEOLOGV. 
 
 13 
 
 Here the teacher will take a beer or 
 champaign glass, (fig. 2,) will put 
 into it some pieces of zinc or iron 
 filings, and pour over them a small 
 quantity of oil of vitriol (sulphuric 
 acid) diluted with twice ils bulk 
 of water, and cover the glass for a 
 few minutes. On putting in a 
 lighted taper, an explosion will 
 take place. He will then repeat 
 the same experiment in a phial, 
 into the cork of which he has introduced a common gas 
 jef, (Bg. 3.) After a short time, when the hydrogen gas 
 produced has driven out all the common air fi-om the bot- 
 Fig. 3. tie, a light may be applied to the 
 
 jet, when the gas will take fire and 
 burn. The cork and jet may now 
 be taken out of the bottle, and a 
 lighted taper introduced into it, 
 when the taper will be extjngushed, 
 while the gas itself will take fire 
 and burn at the mouth of the bottle. 
 Lastly, if the teacher possesses a 
 small balloon, he may fill it with 
 the gas by attaching it to the mouth 
 ' the bottle, and may thus show that 
 the gas is so light that it will carry heavy bodies up with 
 it through the air. 
 Q. tVhat is oxygen ? 
 
 A. Oxygen is also a kind of air in which a candle 
 bitrns with great brilliancy, in which animals also can 
 live, and which is lieavier than hydrogen or common air. 
 It forms one-fifth of (he bulk of the air we breathe. 
 
14 
 
 CATECHISM OF AGRICTTLTURAL 
 
 The teacher will here exhibit a bottle 
 of oxygen gas, (fig. 4,) ami show 
 how rapidly and brillianlly a lighted 
 taper burns when introiluccd into it. 
 The least troublesome mode of prepar- 
 ing oxygen gas, is lo heat red oxide 
 of mercury in a small retort by 
 means of a spirit lamp, and lo col- 
 lect the metallic mercury as it dis- 
 tils over and trickles down the beak 
 of the retort This is not so very 
 a costly process as it appears to be, 
 since there is no loss of anything. A 
 pound of red oxide costs 6s. Sd., and 
 gives 14 oz. of metallic mercury, 
 worth 4s. 8d. 
 Oxygen gas may also be prepared by mixing sulphuric acid 
 (oil of vitriol,) with black oxide of manganese, in fine pow- 
 der in a retort, and applying the heat oT a lamp ; or by rub- 
 bing together in a mortar e |ual weights of oxide of copper 
 and chlorate of potash, putting the mixture into a small re- 
 tort, and applying the lamp as before. The last is the 
 quickest method of the three. 
 Fig 5 
 
 * The properties of oxygen may be 
 
 very well shown without the neces- 
 sity of collecting the gas. Thus, 
 the mixture of chlorate of potash 
 and oxide of copper above descri- 
 beil, may be put into an open tube, 
 (flg. 5.) and the flame of a lamp 
 applied for a few minutes; when a 
 bit of red hot charcoal, or a match 
 of which a spark is still red at the 
 extremity, will burn brilliantly if introduced at a. 
 
CHEMISTRY AND GEOLOGY. 
 
 15 
 
 *'g- ". Or the mixluie may be put into a com- 
 
 mon open flasU, (tig. 6,) anil heat ap- 
 plied, when a taper, or phosphorus, or 
 charcoal, or sulphur, may be inlrmluc- 
 etl at the emi of a wire, and will burn 
 brilliantly. 
 
 Q. IVhat is nitrogen ? 
 
 A. Nitrogen is also a kind of air 
 
 differing from both the other two. 
 
 Like hydrogen, a taper will not burn 
 
 nor will an aninnal live in it, but ui>- 
 
 like hydrogen, it will itself not burn, 
 
 and therefore does not take fire when hronght near ihe 
 
 flame of a candle. It is alillle lighter Ihan atmospheric 
 
 air, of which it forms four-fifths of the bulk. 
 
 Fig. 7. 
 
 The teacher will here exhibit a 
 
 bottle of this gas, and show 
 that a lighted taper is extin- 
 guished when introducei-l into 
 it. 
 The easiest mode of preparing 
 nitrogen, is by mixing togeth- 
 er a quantity of sal ammoniac 
 with half ils weight of salt- 
 petre, both in tine powder, 
 and heating them in a retort 
 ovf r a lamp. The gas which comes off is collected over 
 water, as shown on the following page, (fig. 8.) 
 
16 CATECHISM OF AGEICTJLTUKAL 
 
 Fig. 8. 
 
 Q. Do all vegetable substances contain these four ele- 
 mentary bodies ? 
 A. No, the greater number contain only three, viz: 
 carbon, hydrogen, and oxygen. 
 
 Q. Name some of the more common substances which 
 contain only these three ? 
 A. Starch, gum, sugar, the fibre of wood, oils, and 
 fats, contain only these three elements. 
 Q. Of what substances does the inorganic part of the 
 plant consist ? 
 A. The inorganic part of plants contains from eight 
 to ten ditferent substances, namely : potash, soda, lime, 
 magnesia, oxide of iron, oxide of manganese, silica, 
 chlorine, sulphuric acid, or oil of vitriol, and phospho- 
 ric acid. 
 
 Here the teacher may exhibit to his pupils, potash in the 
 form oCthe common pearl ash of the shops; soila, in that 
 of the common soda of the shops; lime and magnesia, in 
 
CHEMISTRY AND GEOLOGY. 17 
 
 the lotmsol quicklime and calcined magnesia; oxide of iron, 
 in the form of rust of iron; silica, in the form of a piece 
 of Jlint, rock crystal or quartz, (chucky stone;) abottle of 
 chlorine gas, one of sulphuric acid, (oil of vitriol,) and 
 one containing a little phosphoric acid, or burnt bones 
 in which phosphoric acid is present. By placing the86 
 substances before the eyes of (he pupils occasionally, 
 and allowing them to determine and taste them, they 
 will soon become familiar with their names, and with 
 their several qualities. 
 
 Q. What is potash ? 
 
 A. The common potash of the sliops is a white pow- 
 der, which has a peculiar taste called an alcaline taste, 
 and which becomes moist, and at last runs to a liquid 
 when exposed for a length of time to the air. It is ob- 
 tained by washing wood ashes (the ashes left by wood 
 when it is burned,) with water, and afterwards boiling 
 the liquid to dryness. 
 
 The teacher will here allow his pupils to taste the potash, 
 that they may become familiar with the meaning of the 
 word alcaline as applied to (aste. (See p. 20.) 
 Q. What is soda ? 
 
 A. The common soda of the shops is a glassy or crys- 
 tallized substance, which has also an alcaline taste, but 
 which, unlike potash, becomes dry and powdery by being 
 exposed to the air. It is manufactured from sea salt. 
 The teacher will show a crystal of the common soda of the 
 shops, and explain the meaning of the word crystallized- 
 Q. What is lime? 
 A . Lime or gMicfe-lime is a white earthy substance 
 2 
 
18 CATECHISM OF AGRICULTURAL 
 
 wliich is obtained by burning common limestone in Ihe 
 lime-kiln. It has a slightly burning taste, and becomes 
 hot and slakes when water is poured upon it. 
 
 The teacher will exhibit a piece of quicldimc, will allow 
 his pupils to tasle it, and will pour water upon it, that it 
 may fall to powiler. They will thus become familistr 
 with the word slake. 
 Q. IVhat is magnesia ? 
 
 A. Magnesia is the white powder sold in the shops 
 under the name of calcined mai;nesia. It has scarcely 
 any taste, and is extracted from sea water and from some 
 kinds of limestone rock called Magnesian limestones. 
 Q. H'hal is iron 7 
 
 A. Iron is a hard bluish gray metal, which is manu- 
 factured in large quantities incur iron- works, and is used 
 for a great variety of useful purposes. 
 
 The teacher will here explain the word metat, by show- 
 ing that such common metals as iron, copper, leail, sil- 
 ver and goUl, have a lustre, weight, anil malleability not 
 possessed by wood, stones, and other substances to which 
 the name of metals is not applied. 
 Q. ffhnt is oxide of iron ? 
 
 A. When polished iron is exposed to the air it gradu- 
 ally becomes covered with rust. This rust consists of 
 tbe metal iron, and of the gas oxygen which the iron has 
 attracted from the air, and hence it is called an oxide 
 of iron. 
 
 The teacher will explain more fully, that, when metals 
 combine with oxygen, they form new substances, to 
 Which the name of oxides is given, and illustrate this by 
 
CHEMISTRY AND GEOLOGY. 19 
 
 a reference to the red oxide of mercury, which, by the 
 heat of the lamp he had resolved or decomposed into oxy 
 gen gas and metallic mercury. (Sec. fig. 8.) 
 Q. What is oxide of manganese ? 
 
 A. Oxide of manganese is a substance very much like 
 oxide of iron, which occurs in soils and plants, usually 
 in very small quantity. 
 Q. fVhat is silica ? 
 
 A. Silica is the name given by chemists to the sub 
 stance of flint, of rock-crystal, and of sandstones. 
 Q. What is chlorine 7 
 
 A. Clilorine is a kind of air which has a greenish-yel- 
 low colour, and a strong suffocating smell. ♦ A taper 
 burns in it with a dull smoky flame. It exists in com 
 mon salt in large quantity. 
 
 The teacher will exhibit a bottle of this gas, and may ad- 
 vert to the remarkable fact that this very noxious gas 
 should form more than half the weight of the very 
 wholesome substance common salt, 100 lbs. of common 
 salt containing 60 lbs. of chlorine. This gas is readily 
 prepared by pouring muriatic acid on black oxide of 
 manganese in a retort^ and applying a gentle heat. It 
 should be collected over hoi water. 
 An easier mode of showing some of the properties of thia 
 gas, is to put a little dry chloride of lime into the bottom 
 of a tall glass, (fig. 2,) anil pour upon it strong sulphuric 
 aciil. Chlorine gas will be given off, and will gradually fill 
 the lower part of the glass, and the boys may then be made 
 to smell it, and it maybe shown, 1st. That a taper burns 
 in it with a smoky flame and is soon extinguished. 
 
 * U is two and a half tiinea heavier than 
 
20 CATECHISM OF AGRICULTURAL 
 
 2d. That it is much heavier than common air, by pour- 
 j ing it from one glass to another, or upon the flame of a 
 candle, (figs. 10 and 11.) 3d. That phosphorus takes 
 fire in it of its own accord. 4th. That it gives a red 
 color to a solution of iodide of potassium when poured 
 upon its surface, or a purple color if a little dissolved 
 starch be previously mixed with the solution of the 
 iodide. 5lh. That the color of red cabbage is discharg- 
 ed by it, (see under sulphuric acid.) It is not absolutely 
 necessary for the teacher to make all these experiments, 
 but they are very simple, and they are likely so to im- 
 press the knowledge of this gas, chlorine, upon tiie mind 
 of the pupil, that he will never forget it. 
 
 Q. fVhat is sulphuric iicii or oil of vitriol I 
 
 A. Sulphuric acid or oil of vitriol is a very sour burn- 
 ing, oily liquid, which is manufactured from burning 
 sulphur, (brimstone.) It exists in common gypsum, in 
 alum, and in Glauber and Epsom salts. 
 
 The teacher will here exhibit oil of vitriol, and show that 
 when a piece of straw is put into it, it is charreil or burn- 
 ed black. He will also exhibit gypsum, alum, Glauber 
 and Epsom salts, and show tliat, though the sulplimic 
 acid exists in them, they have none of its burning pro- 
 perties. He will also explain the meaning of the term 
 acid or sour. Besides being more or less sour to the 
 taste, he may show that acid substances redden vegetable 
 colors — such as decoction of red cabbage or of violets, 
 or of the substance he will buy in the shops by the name 
 of litmus; and that alcaline substances, or alcali, such as 
 hartshorn, common soda, pearl ash, or quick lime, re- 
 store the blue color. 
 
//^"^"""^^^^^ 
 
 CHEMISTRY AND GEOLOGY. 21 
 
 Q. What is phosphoric acid ? 
 
 A. Phosphoric acid is also a very sour substance, 
 which is formed by burning phosphorus in the air. It 
 exists in Urge quantity in the bones of animals. 
 
 If the teacher possess any phospho- 
 rus, he may here show how i( burns 
 with u-hite fumes in the air, and 
 may collect these white fumes — 
 which are phosphoric acid — by 
 holding over them a cold glass 
 or metal jilatc, or he may sim- 
 ply burn the phosphorus in a little clip under a tumbler, 
 (fig. 9.) 
 A still simpler way of making his pupils acquainted with 
 phosphorus and phosphoric acid, is to take a common 
 lucifer match, of the variety that kindles without explo- 
 sion, and to rub the end of it on the sand-paper so gently 
 as not to kindle it. If it be now brought near the nose 
 the smell of phosphorus will be perceived. If it be 
 again rubbed so as to lake fire, it will burn with a white 
 flame, and will for a short time give a white smoke. 
 Thin while smoke is phosphoric acid. It is a curious fact, 
 that about 200,000 lbs. of phosphorus are used In Lon- 
 don every year for the manufacture of Lucifer matches 
 alone. 
 Q. jirc all these substances to be found in the inorganic 
 part of plants ? 
 A. Yes, they are to be found in the ash of all our usu- 
 ally cultivated plants. 
 
 Q. Do all plants leave the same quantity of ash when 
 burned ? 
 A. Xo Some leave much more ash than others 
 
22 CATECHISII OF AGRICULTURAL 
 
 Thus 100 lbs. of hay may leave 9 or 10 pounds of ash, 
 while 100 lbs. of wheat leave less than 2 lbs. of ash. 
 Q. Does the mh of different plants contain all these 
 substances in the same proportion ? 
 
 A. No. They exist in different proportions in the ash 
 of different plants — the .ish of wheat, for example, con 
 tains more phosphoric acid than that of hay, while tha* 
 of hay contains more lime than the ash of wheat. 
 
 Compare Tables I. and III. pages 38 and 43. 
 
 II. OF THE ORGANIC FOOD OF PLAXTS. 
 
 Q. Do plants require food as animals dot 
 
 A. Yes, all plants require constant supplies of food iii 
 order that they may live and grow. 
 Q. Where do plants obtain their food 1 
 
 A. They obtain it partly from the air and partly from 
 the soil. 
 Q. How do they take in their food ? 
 
 A. They take it in by their leaves from the air, and 
 by their roots from the soil. 
 Q. Do plants require two distinct kinds of foodi 
 
 A. Yes, they require organic food to support their or- 
 ganic pjrt, and inorganic food to support their inorganic 
 part. 
 Q. Whence do they obtain their organic food ? 
 
 A. They obtain their organic food partly from the 
 air and partly from the soil. 
 Q. Whence do they obtain their inorganic food? 
 
 A. They obtain their inorganic food wholly from the 
 soil in which they grow. 
 
CHEMISTRY AND GEOLOGY. 
 
 23 
 
 Q. In what form do plants take in organic food from 
 the air ? 
 A- In the form chiefly of carbonic acid gas. 
 Fig. 10. Q. fVhat is carbonic acid gas 1 
 
 A. It is a kind of air which has no 
 colour, but has a peculiar smell. Burn- 
 ing bodies are extinguislied in it, and 
 animals die, and it is heavier than com 
 mon air. It causes the boiling up of so- 
 da water, and tlie frothing of beer, and 
 forms nearly half the weight of all lime- 
 stone rocks. 
 
 Here the teacher will prepare carbonic 
 aciJ gas, by pouring dilute muriatic 
 acid, (spirit of salt,) upon bits of lime- 
 stone, or of the common soila of the shops, in a tall co- 
 vered beer glass, (as in fig. 2.) He will show that a 
 burning taper is ex- 
 tinguished by this 
 gas; but that it tioes 
 not, like hyilrogen, 
 lake fire itself; — 
 that it is so heavy 
 that it may be pour- 
 ed from one glass to 
 anoiher, (fig. 10;) 
 anil that when pour- 
 ed from a large tum- 
 bler a common can- 
 dle may be put out 
 by it, (fig. ]].) 
 
 Fig. n. 
 
24 CATECHISM OF AGRICULTURAL 
 
 Q. Does carbonic acid gas form a large part of the at' 
 mospheric air ? 
 
 A. No, Ihe atmospheric air consists almost entirely 
 of a mixture of oxygen and nitrogen gases. Five gai 
 Ions of air contain about four of nitrogen and one of 
 oxygen, but in 5000 gallons there are oiJy 2 gallons ol 
 carbonic acid gas. 
 Q. Do plants drink in much carbonic acid from the air ? 
 
 A. Yes, they drink in a very large quantity. 
 Q. I/ou' can plants drink in so large a quantity of this 
 gas from the air, which contaiiis so little'! 
 
 A. They spread out their broad thin leaves in great 
 numbers through the air, and thus are able to suck in the 
 carbonic acid from a large quantity of air at the same 
 time. 
 Q. How do they suck it in ? 
 
 A. By means of a great number of very small open- 
 ings or mouths which arespreadcvery where, especially 
 over the under surface of the leaf. 
 Q. Do the leaves suck in this carbonic acid at all times ? 
 
 A. No, only during the day time. During the night 
 they give olf a quantity of carbonic acid. 
 Q. IFhat does carbonic acid consist off 
 
 A. Carbonic acid consists of carbon, or charcoal, and 
 oxygen. 
 
 6 lbs. of carbon and 16 lbs. of oxygen form 22 lbs. of car- 
 bonic aciil. 
 Q. Hoiv do you prove this ? 
 
 A. By burning charcoal in oxygen gas, when carbon- 
 ic acid gas will be formed. 
 
CHEMISTRY AND GEOLOGY. 
 
 25 
 
 The leacher will show this experiment by intioilucing a 
 piece of red hot charcoal into a bottle of oxygen gas un- 
 til the charcoal is extinguished, when, upon putting a 
 lighted taper into the bottle, he will find carbonic acid 
 has been formed, for the taper will be extinguished. 
 Q. Does the plant retain both the carbon and the oxygen 
 contained in the carbonic acid that is absorbed by 
 its leaves ? 
 A. No, it retains only the carbon, giving off the oxy- 
 gen again into the air. 
 
 Q. How do you show that the leaves give off this oxygen 
 gasl 
 A. By putting a few green leaves under a tumbler or 
 Fig. 12. gas-receiver full of water, 
 
 and selling lliem out in the 
 .sunshine, when small bub- 
 bles of oxygen gas will be 
 seen to rise from the leaves, 
 and to collect in the upper 
 part of the tumbler (fig. 12.) 
 Q. Do the leaves of plants 
 drink in any thing elst 
 from the atmosphere ? 
 A. Yes, they drink in watery vapour. 
 Q. What purpose does this vapour serve ? 
 
 A. It serves in part to moisten the leaves and stems, 
 and partly to form the substance of the jdant itself. 
 Q. In what form do plants take in carbon from the 
 soil ? 
 A. In the form of carbonic acid, humic acid, and 
 
26 CATECHISM OF AGRICULTURAL 
 
 some other substances which exist in the black vegeta 
 
 ble matter of tlie soil. 
 
 If the teacher wishes to form humic acid, he has only to 
 dissolve a little common soila in water, boil the solution 
 upon finely powilereil peat or rich dark soil, pour off 
 the solution when it has stooil to settle, and add weak 
 spirit of salt to it. Brown flocks will fall, which are 
 humic acid. This huniic acid consists of carbon and 
 water only — see the table on page twenty-eight. 
 
 Q. /'I what forms do plants derive nitrogen from the 
 soil? 
 A. In the forms of ammonia and nitric acid. 
 The properties of these two substances are described in 
 Section VI., where they are treated of in connection 
 with certain manures in which they exist. 
 
 III. — OF THE SUBSTANCE OF PLANTS. 
 
 Q. What does the substance of plants chiefly consist of 7 
 
 A. The substance of^Knts chiefly consists of woody 
 fibre, starch, and gluten. 
 Q. What is woody fibre 1 
 
 A. Woody fibre is the substance which forms the 
 greater part of all kinds of wood, straw, hay, and chaff, 
 of the shells of nuts, and of cotton, flax, hemp, &c. 
 Q. What is starch ? 
 
 A. Starch is a white powder, which forms nearly the 
 whole substance of the potatoe, and about halfthe weight 
 of oat-meal, wheaten flour, and of the flour of other 
 kinds of grain cultivated for food. 
 Q. What in gluten ? 
 
 A. Gluten is a substance like bird-Iirae, which exists. 
 
CHEMISTRy AND GEOLOGY. 
 
 27 
 
 along with starch, in ahnost all plants. It may be ob- 
 tained from wliealen flour, by making it into a dough, 
 and washing it with water, (fig. 13.) 
 
 Fig. 13. The teacher will here mix 
 
 flour with water into a 
 dough, and wash it with 
 water upon a piece of 
 thin muslin tied over the 
 mouth of a tumbler or 
 lar^e glass, and will show 
 how the milky wa'er car- 
 ries the starch through the 
 muslin, and leaves the 
 gluten beliind, and how, 
 after a time, the slarch 
 settles at the bottcim of the 
 water, in the form of a 
 white pow^ler. 
 
 Q. Which of these three substances is usually moat 
 abundant in plants ? 
 A. The woody fibre is the most abundant in the stems 
 of plant?) and the starch in their seeds. 
 Q. Is starch found in the roots of plants ? 
 
 A. Yes, it exists abundantly in the potatoe and other 
 similar roots. 
 
 Q. What do woody fibre and starch, and also gum and 
 sugar consist of! 
 A. They all con-ist of carbon and water only. 
 The teacher may suspend on the walls of his school-room 
 
 the followmg table: 
 36 lbs. of carbon and 36 lbs. of water form 72 lbs. of 
 woody fibre. 
 
88 CATECHISM OF AGRICULTURAL 
 
 36 lbs. of carbon and 45 lbs. of water form 81 lbs. of dry 
 
 starch or gum. 
 36 lbs. of carbon and 49^ lbs. of water form 85i lbs. of 
 loaf-sugar or sugar-candy; and 36 lbs. of carbon and 27 
 lbs. of water form 63 lbs. of humic acjd. 
 Q. Mo-y these substances then be formed from the kinds 
 of food which the leaves drink in from the air ? 
 A. Yes, because the leaves drink in carbonic acid and 
 water. 
 
 Q. Can you tell, then, why the leaves give off the oxygen 
 of the carbonic acid into the air! 
 A. Yes, they require only carbon and water to form 
 the woody fibre and starch, of which they consist, and 
 therefore they give ofi'the oxygen of the carbonic acid 
 because they cannot make use of it. 
 Q. If plants suck in so much carbonic odd from the 
 air, may they not at length rob the air of the whole 
 of the carbonic acid it contains ? 
 A. No, because new supplies of tliis gas are continu- 
 ally returning into the air. 
 Q. Whence do those supplies come ! 
 
 A. They come from three sources ; first, from the 
 breathing of animals, since all animals throw off a small 
 quantity of carbonic acid from their lungs every time 
 they breathe. 
 
 Second, from the burning of wood, coal, candles, &c., 
 since the carbon which wood contains, when it burns in 
 the air, forms carbonic acid gas just as carbon when 
 burned in oxygen does. 
 
 Third, from the decay of vegetables and roots in the 
 soil, since this decay is only a slow kmd of burning, by 
 
CHEMISTRY AND GEOLOGY. 29 
 
 which the carbon of plants becomes converted into car- 
 bonic acid. 
 
 Q. Do animals and plants thus appear to live for each 
 other's support ? 
 A. Yes, the animal produces carbonic acid, upon 
 which plants live, and from this carbonic acid and water 
 together, plants produce starch, &c., upon which animals 
 'ive. 
 
 Q. Woody fibre, starch, gum, and sugar consist of car- 
 bon and toater only; of what does water itself con- 
 sist ? 
 A. Water consists of oxygen and hydrogen. 
 Q. How much of each of these elements is contained in 
 water ? 
 A. Every 9 lbs. of water contain about 8 lbs. of oxy- 
 gen, and 1 lb. of hydrogen. 
 
 Q. Is it not a very extraordinary thing that liquid ica- 
 ter, which puts out all fire, should consist oj two 
 gases, one of which (^hydrogen,) burns readily, 
 while in the other (^oxygen,') bodies burn with great 
 brilliancy ? 
 A. Yes, it is very wonderful; but there are many oth- 
 er substances the composition of which is almost equally 
 extraordinary. 
 Q. Can you name any such substances ? 
 
 A. Yes, it is almost equally extraordinary that white 
 starch should consist of black charcoal and water only, 
 — and that sugar and gum should consist of the same 
 elements as starch and woody fibre. 
 Q. Of what elements, i/ien, do all these substances con- 
 
30 CATECHISM OF AGRIC0LTUEAL 
 
 A. They all consist of carbon, hydrogen and oxygen. 
 
 The teacher may lake this opportunity of explaining more 
 particularly the woril elements, contrasting the nature of 
 the elementary boities, hydrogen, oxygen, carbon, and 
 nitrogen, tvhich cannot be separated or split up into mort 
 than one kind of viatter, with such compound bodies as 
 carbonic acid, water, starch, and oxide of mercury, 
 which can be separated into more than one. 
 
 Q. Of what does gluten cmisist ? 
 
 A. Gluten consists of all the four elements— carbon, 
 hydroa^en, oxygen, and nitrogen — ^united together. 
 Q Does the plant derive from the air all the elements 
 of which gluten consist si 
 
 A. No, it may obtain carbon, hydrogen, and oxygen, 
 as we have seen, from the air, but the nitrogen it obtains 
 almost solely from the soil. 
 
 IV.^OF THE SOIL. ON WHICH PLANTS GKOW. 
 
 Q. TVhat does the soil consist of! 
 
 A. The soil consists of an organic or combustible, 
 and of an inorganic or incombustible pait. 
 Q. How do you show this ? 
 
 A. By heating a portion of soil to redness on a bit of 
 sheet iron, or on the end of a knife, either in Ihe fire or 
 over a lamp. The soil will first turn black, showing the 
 presence of carbonaceous matter, and will afterwards as- 
 sume A grey brown or reddish color as this black orga- 
 nic matter burns away. 
 
CHEMISTRY AND GEOLOGY. 3l 
 
 Fig. 14. The teacher will show 
 
 this experiment, 
 anil will explain 
 (he meaning of 
 the new wonlcor 
 bonace&us^ 
 Q Whence is tha 
 organic part of 
 the soil derivedi 
 A. It is derived from the roots and stems of decayed 
 plants, and from the dung and resnains of animals and 
 insects of various kinds. 
 
 Q. Does this organic part form a large proportion of 
 the soil ? 
 A. Of peaty soils it forms sometimes three-fourths of 
 the whole weight; but of rich and fertile soils it does 
 not usually form more than from a twentieth to a tenth 
 of the whole weight. 
 
 Q. Can a soil bear good crops which does not contain 
 a considerable proportion of organic matter? 
 A. Not in our climate. A rich soil generally con- 
 tains at least one-twentieth of its weight (5 percent.) of 
 organic matter. 
 
 Q. Does the organic matter increase or diminish in tht 
 soil, according to the way in which it is cultivated f 
 A. Yes, it diminishes when the land is frequently 
 ploughed and cropped, or badly manured ; and it in- 
 creases when the land is planted, when it i.-s laid down to 
 permanent pasture, or when large doses of farm-yard 
 manure or of peat compost are given to it. 
 
32 CATECHISM OF AGKICXTLTUEAL 
 
 Q. fVhat purpose does this organic matter serve in the 
 soill 
 A. It supplies the organic food which plants draw 
 from the soil through their roots. 
 
 Q. Do plants draw much of their organic food from 
 the soil ? 
 A. The quantity they draw from the soil varies with 
 the kind of plant, with the kind of soil, and with the sea- 
 son; but it is always considerable, and is necessary to 
 the liealthy growth of the plant. 
 
 Q. Jf plants always draw this organic matter from the 
 soil, will the soil not become gradually poorer and 
 less productive 1 
 A. It will, if badly managed and constantly cropped. 
 Q. Then how can you keep up the supply 1 
 
 A. By ploughing in green crops, — by growing clo- 
 vers and other i)lants which leave long roots in the soil, — 
 by restoring all the hay and straw to the land in the 
 form of manure, — or by laying down to pasture. 
 
 The teacher may illuslrate this answer beneficially, by re- 
 ferring to the practice in his own or the neighboring 
 towns, and pointing out its advantages or defects. 
 
 Q. IVhence is the inorganic part of the soil derivedf 
 
 A. The inorganic part of the soil is derived from the 
 crumbling down of the solid rocks. 
 
 The teacher will satisfy his pupils — by drawing their at- 
 tention to the decaying walls of buililings, to the heaps 
 of what is called rotten rock, (decomposed trap or whin- 
 stone) — of limestone, gravel, &c. which are found at the 
 foot of the hills — that rocks really do crumble down in 
 the air. 
 
CHEMISTRY AND GEOLOGY. 33 
 
 Q. Of what do these rocks principally consist ? 
 
 A. They consist of more or less hardened sandstones, 
 limestones and clays. 
 
 The teachers may exhibit as specimens of 
 
 Sandstone — red and white, or other freestones; 
 Limestone — chalk and blue or other limestones; 
 Clays — roofing slate, and the shale or shiver of the coal 
 beds. 
 
 Q. Do soils consist principally of the same substances^ 
 
 A. Yes, soils consists principally of sand, clay and 
 lime. 
 
 Q. ^010 would you name a soil which contained one of 
 these substances in large quantity ? 
 
 A. If it contained very much sand, I would call it a 
 sandy soil; if much clay, a more or less stiff clay soil; 
 if much lime, a calcareous soil. 
 
 The teacher will explain the new word calcareous. 
 Q. But if the soil contained two or more of them in 
 large proportions how xcould you name it ? 
 
 A. A mixture of sand and clay with a little lime, I 
 would call a loam; if much lime was present, I would 
 call it a calcareous loam; and if it were a clay with 
 much lime, I would call it a calcareous clay. 
 Q. TVhat do you understand by light and heavy lands ? 
 
 A. Light lands are such as contain a large proportion 
 of sand or gravel; heavy lands, such as contain much 
 clay. 
 
 The teacher may illustrate this, by referring to the dififer- 
 ent kinds of land which occur in the neighborhood. 
 
 3 
 
34 CATECHISM OF AGRICULTURAL 
 
 Q. JVhich of these two kinds of land is most easily and 
 cheaply caltivated ? 
 
 A. The liglit lands, called oflen also barley or turnip 
 soils. 
 Q. lyiiy are these lands called barley or turnip soils'! 
 
 A. Because they have been found to be peculiarly 
 fitted for the growth of barley and of turni]), and other 
 green crops, 
 
 Q. Do heavy or light lands usually stand most in need 
 of draining"! 
 
 A. The heavy clay lands retain water most, and 
 should therefore be generally drained first. 
 Q. Do light lands not require draining 1 
 
 A. Yes, though dry at tlie surface, such soils are of- 
 ten wet beneath, and would pay well for draining. 
 
 The teacher may illustrate this, by referring his pupils to 
 what they may see on the sea beach, or on the banks of 
 e river, where the surface of the sand may be dry and 
 drifted by the wind, while it is quite wet a few inches 
 below. 
 
 Q. 7b what depth would you drain your lands. 
 
 A. If I could get a fall I woidd never have my drains 
 sballower than 30 inches. 
 Q. JVhy loould you put them so deep ? 
 
 A. Because the deeper tlie dry soil is made, the deep- 
 er the roots can go in search ol fond. 
 Q. Can you give me any other reason ? 
 
 A. Yes, when my drains are so deep I can go down 
 20 or 22 inches with my subsoil plough, wjtliout any 
 risk of injuring them. 
 
CHEMISTRY AND GEOLOGY. 35 
 
 Q. Does draining serve any other purpose besides that 
 of carrying off the water from the land? 
 A. Yes, it lets in the air to the subsoil, and allows the 
 rain water to sink down and wash out of it any thing 
 wliich may be hurtful to the roots of plants. 
 Q. Do such hurtful substaiices often collect in the sub- 
 soil? 
 A. Yes, very often, and crops which look well at first, 
 often droop or fail altogether when their roots get down 
 to the hurtful matter. 
 
 The teacher may illiislrale this answer by referring fo the 
 
 layers of iron-ochre, or part, which in many districts 
 
 are met with in the subsoil,- — and to such curious facts 
 
 as that observeil in the East of Fife, where the beans 
 
 and oats, which look well up to April or May, often 
 
 blacken and fail in June or July, when the roots get 
 
 down to the ochrey subsoil. It is the local saying when 
 
 this hai'pens — that the beans or oats have gone to Auchter- 
 
 muchty — a fair being helil there about the time when the 
 
 beans usually fail. 
 
 Q. Why are many of the heaviest clays in the country 
 
 laid down to permanent pasture ? 
 
 A. Because the expense of ploughing and working 
 
 these soils is so ^reat, that the value of the grain reaped 
 
 from them is not sufficient to pay the farmer for his 
 
 trouble. 
 
 Q. Hon could these heavy clay lands be rendered lighter 
 and more cheap to work ? 
 A. By draining, subsoil ploughing, and by the addi- 
 tion of lime or marl when it is required. 
 
 The teacher will here explain to his pupils the diSerence 
 
36 CATECHISM OF AGEICULTURAL 
 
 between common ploughing, which merely turns over the 
 surface soil, — subsoil ploughing, which only stirs and 
 loosens the subsoil, — and trench ploughing or trenching, 
 which brings the subsoil to the surface. 
 
 Q. JVould the land after this treatment also give greatei 
 crops of grain 1 
 A. Yes, not only would it be more cheaply worked, 
 
 but it would yield a greater number of bushels of wheat 
 
 per acre than before. 
 
 Q. Would this increase be s^ifficient to pay the cost of 
 draining ? 
 A. Yes, the cost of draining clay lands is generally 
 
 paid back in three, or, at the utmost, in five years, and 
 
 the crops still continue greater than before. 
 
 V. — OF THE IXOKGANIC FOOD OF PLANTS. 
 
 Q. What are the purposes served by the inorgan ic part 
 of the soil ? 
 A. The inorganic or earthy part of the soil serves two 
 purposes : first, it serves as a medium in which the roots 
 can fix themselves, so as to keep the plant in an upright 
 position; and Seconal, it supplies the plant with inorganic 
 food. 
 
 Q. The inorganic part of the soil consists chiefly of 
 sand, clay and lime; does it contain no other sub- 
 stances ? 
 A. Yes, it contains small quantities of eight or nine 
 other substances. 
 Q. Name these substances. 
 
 A. Potash, soda, magnesia, oxide of iron, oxide of 
 
CHEMISTRY AND GEOLOGY. 37 
 
 tniinganese, sulphuric acid, phosplioric acid, and chlo- 
 rine. 
 
 Q. Are not these the same substances tvhich exist in the 
 ash or inorganic part of plants ? 
 A. Yes, the same substances exactly — only they form 
 a much larger proportion of the soil than they generally 
 do of plants. 
 
 Q. Do you understand then where plants obtain all the 
 inorganic matters they contain ? 
 A. Yes, they obtain them from the soil only. 
 Q. fyhy can they not obtain them from the air ? 
 
 A. Because potash, soda, magnesia, &c. do not exist 
 in the air. 
 Q. How does this earthy matter enter into the plant 1 
 
 A. It enters by the roots. 
 Q. In what state ? 
 
 A. In a state of solution. The rain and spring wa- 
 ters dissolve them and carry them into the roots. 
 
 Here the teacher will explain the meaning of the new 
 words dissolve and solution — showing how salt anil sugar 
 melt away or dissoh'e in water, (orming cleSLV solutions of 
 salt or sugar, in which these subslances can be recog- 
 nized only by the sense of taste — but from which they 
 may again be obtained vnchangedj by boiling otf the 
 water. 
 Q. Do all soils contaiii every one of the inorganic sub- 
 stances, potash, soda, lime, Sfc, which you have 
 mentio7ied ? 
 A. All fertile or productive soils do. 
 Q. fVhij must a fertile soil contain them aW! 
 
3S 
 
 CATECHISM OF AGEICULTUKAL 
 
 A. Because plants require them all for their healthy 
 
 growth. 
 
 Q. Do plants require them all in equal proportion ? 
 A. No. Plants must have a certain small quantity of 
 
 each of Ihem, but they require more of some substances 
 
 than of others 
 
 The teacher may illustrate this question by directing the 
 attention of his pupils (o the following table, which he 
 shouKl cause to be copied upon a large piece of cotton 
 or paper, or a black-board, and hung upon the wall of 
 his school-room. He can thus readily point out, that, 
 while 1,000 lbs. of red-clover hay leave in all 75 lbs. of 
 ash when burned, there are present in this ash 2S lbs. of 
 liine, but only 20 lbs. of potash, and less than 4 lbs. of 
 magnesia, — and so on with the ash of the other kinds 
 of hay mentioned in the table. 
 
 I. — Quantity and composition of the ash left by 1,000 
 
 lbs. of hay from 
 
 
 Ryegrass 
 
 CLOVtR. 
 
 Lucerne. 
 
 Red. 
 
 White. 
 
 Potash, 
 
 Soila, 
 
 9 
 
 4 
 
 7 
 
 I 
 trace 
 2S 
 
 ^ 
 
 trace 
 
 20 
 
 5} 
 28 
 
 3 
 trace 
 
 4 
 
 ^i 
 
 31 
 6 
 
 1; 
 
 is" 
 H 
 
 5 
 2 
 
 13i 
 6 
 
 48 
 
 i 
 
 13 
 3 
 
 Lime, 
 
 Magnesia 
 
 Oxide of iron, 
 
 Silica, 
 
 Sulphuric acid,. . . 
 Phosphoric acid, . 
 
 
 53 lbs. 
 
 74] lbs 
 
 89i lbs 
 
 94^ lbs 
 
CHEMISTRY AND GEOLOGY. 39 
 
 This table will suggest to the teacher many inslructive 
 questions — which his pupils will readily untlcrslanil and 
 answer, when they have the table hanging before them. 
 
 Q. Are those substances which are present in the plant 
 
 in such minute quantities, really necessary to ita 
 
 growth ? 
 
 A. They appear to be all equally necessary — just as 
 
 the few ounces of nails or glue are as necessary to the 
 
 joiner in making- a box, as the many pounds of wood 
 
 which the box contains. 
 
 Q. Suppose a soil to be entirely destitute of one of 
 these substances, what would happen"! 
 A. Good crops would not grow upon it. 
 Q. Suppose it to contain a large supply of all the others, 
 but only a small supply of some one of these sub- 
 stances, what would happen 1 
 A. Those plants would grow well upon it which re- 
 quire only a small quantity of that one substance, — but 
 those which require a large quantity of it would be 
 stunted and unhealthy. 
 Q. Give me an example. 
 
 A. If the land contained little lime, it might grow a 
 good crop of rye-grass, and yet not be able to grow a 
 good crop of lucerne. 
 
 By refei ring to the above table, the teacher may exercise 
 the uiuleislaniling ol his pupils by asking for other ex- 
 amples of a similar kind, which the intelligent boy 
 will readily give by considering the numbers on the ta- 
 ble. Thus he may say, lucerne requires more phospho- 
 
40 CATECHISM OF AGKICTJLTT7EAL 
 
 ric acid than rye- grass does; therefore if there be little 
 phosphoric acid in the soil, lucerne will not grow so 
 well upon it as rye-grass would do, and so on. 
 Other tables of a similar kind also the teacher may make 
 use of, which he will find in the author's " Elements/' 
 and especially in his "Lectures on Agricultural Chemiitry 
 and Geology." 
 
 Q. Suppose a soil to be destitute of a considerable num- 
 ber of these different inorganic substances, — what 
 icould happen ? 
 A. It would refuse to grow good crops of any kind 
 whatever. It would be naturally barren. 
 Q. Are any soils known to exiit which are naturally 
 barren or naturally fertile. 
 A. Yes; some large tracts of country which have 
 never been cultivated by man, are known to he naturally 
 fertile, and others naturally barren. 
 Q. ffjw is the natural difference between such soils ex- 
 plained .' 
 A. In the fertile soils all those inorganic substances 
 exist, which our cultivated crops require ; in the barren 
 soils some of these substances are wholly wanting. 
 
 This answer the te.icher will illustrate by a reference tn 
 the following table, which he will also hang up on the 
 wall of his school-room. It will do mnch good, indeed, 
 to have this and the preceding table suspended as pernva- 
 nent fixtures in the room. The youngest child will soon 
 become familiar in this way with all the names, — so dif- 
 ficult for grown-up farmers to recollect. 
 
CHEMISTRY AND GEOLOGY. 
 
 41 
 
 II. — Composition of soils of different degrees of fertility 
 
 Organic matter, 
 
 Silica (in tlie sand anil clay,) 
 
 Alumina (in the clay,) 
 
 Lime, 
 
 Magnesia, 
 
 Oxide of iron, 
 
 Oxide of manganese, 
 
 Potash, 
 
 Soda, ) . • « ,. 
 
 „,, '. > chiefly as com. salt. 
 Chlorine ) ^ 
 
 Sulphuric acid, 
 
 Phosphoric aciil, 
 
 Carbonic acid, (combined with 
 
 the lime and magnesia,) 
 
 Loss, 
 
 Fertile, Fertile, 
 without with 
 Manure. Manure, 
 
 97 
 
 648 
 
 57 
 
 59 
 
 81 
 
 61 
 
 1 
 
 2 
 
 <4 
 
 ^2 
 
 1000 
 
 50 
 833 
 51 
 18 
 8 
 30 
 3 
 trace 
 
 1000 
 
 40 
 
 778 
 
 91 
 
 4 
 
 1000 
 
 The soil, of which the composition is given in the first 
 column, had produced crops for 60 years without ma- 
 nure, — and still contained a sensible quantity of all tlie 
 substances required by plants. That in the second column 
 produced good crops when regularly manured, — it teas 
 in want of three or four substances only, u'hich were given 
 to it by tite manure. The third was hopelessly barren, — 
 it was in want of many substances which ordinary manur- 
 ing could not supply. 
 
 Q. May a soil be barren though it contains all the sufr- 
 stances which plants require ? 
 A. Yes, if it contain a very large proportion of some 
 
42 CATECHISM OF AGRICnLTURAI, 
 
 one, such as oxide of iron, which in great quantity is in- 
 jurious to the soil. 
 Q. How would you improve a soil oj this kind? 
 
 A. I would thorough-drain and subsoil it, that the 
 rains might sink through it and wash out the injurious 
 matter, and I would lime it if it required lime. 
 Q. May a soil which is naturally fertile be rendered 
 barren by continued cropping ? 
 
 A. Yes, if the same kind of cropping be carried on for 
 a long time, the land will gradually become less and less 
 productive. 
 Q. Give me an example. 
 
 A. If the same field be cropped year after year with 
 wheat or oats, it will at last become unable to grow either 
 of these crops. 
 Q. Why is this 1 
 
 A Because these crops draw certain substances from 
 (he soil in great abundance, — and after a number of 
 years the soil cannot furnish these substances in suffi- 
 cient quantity. 
 
 Q. What substances does grain especially draw from 
 the soil ? 
 
 A. The seed of our grain crops especially exhausts 
 the soil o{ phosphoric acid, and o{ magnesia. 
 
 The teacher will illustrate this by a reference to the fol- 
 lowing table, repi-csentinj the composition of the ash of 
 the several kinds o( grain usually grown in this country 
 — exclusive of the straw. 
 
CHEMISTRY AND GEOLOGY 
 
 43 
 
 III. Composition of the ash of wheat, oats, barley and 
 rye. 
 
 
 Wheat. 
 
 Oats. 
 
 Barley. 
 
 Rye. 
 
 Potash ami soila, . . . 
 Lime, 
 
 37.72 
 1.93 
 9.60 
 1.36 
 ? 
 
 49.32 
 0.17 
 
 19.12 
 10.41 
 9.98 
 5.08 
 1.2.i 
 46.26 
 
 ""s'.oY 
 
 20.70 
 
 3.36 
 10.0.5 
 
 1.93 
 
 ? 
 40.63 
 
 0.26 
 21.99 
 
 37.21 
 2.92 
 
 10.13 
 0.82 
 ? 
 
 47.29 
 1.46 
 0.17 
 
 
 Oxide of iion, 
 
 Oxiile of manganese, 
 Phosphoric aciil,.. . 
 
 Sulphuric aciil 
 
 Silica, 
 
 
 
 100. 
 
 98.87 
 
 9S.92 
 
 100. 
 
 The teacher will point especially to tae large quantity of 
 phosphoric acid in the above table, and will explain, 
 that, as the grain takes out more of L\^ than of any other 
 substance from the soil, numerous successive crops of 
 grain must exhausi .t of this more than of any other sub- 
 stance. 
 
 Q. How iDOuld you remedy such special exhaustion ? 
 
 A. By returning to the soil (lie particular substances 
 my crops had tnken out. 
 
 Q. Hoio would you return the phosphoric acid for in- 
 stance ? 
 
 A. I would apply bone dust, or g-uano, or some other 
 manure in which phosphoric acid abounds. 
 Q. But with any kind of cropping may not a fertile soil 
 be at length made unproductive ? 
 
 A. Yes, if the crops are carried off' the land, and what 
 they draw from the soil is not again restored to it. 
 Q. Hoiv is this explained ! 
 
44 CATECHISM OF AGRICULTUKAL 
 
 A. Every crop takes away from the soil a certain 
 quantity of those substances which all plants require. 
 If you are always taking out of a purse it will at last be- 
 come empty. 
 Q. Then you liken exhausted land to an empty purse ? 
 
 A. Yes, the farmer takes his money out of the land, 
 and if he is always taking out and putting nothing in, it 
 must at last become empty or exhausted. 
 Q. £ut ij he puis something into the soil now and then, 
 he may continue to crop without exhausting it ? 
 
 A. Yes, if he put in the proper substances, in the pro- 
 per quantities, and at the proper time, he may keep 
 up the fertility of his land — perhaps forever. 
 Q. How much of every thing must the farmer pal into 
 his land to keep it in its present condition ? 
 
 A. He must put it in at least as much as he takes out. 
 Q. 7b make his land belter, how much must he put in ? 
 
 A. He must put in more- than he takes out. 
 Q. But if he is to put into tite land as much or more 
 than he takes out, where is his profit to come from? 
 
 A. His profit consists in this, that he takes off the land 
 what he can SiU for much money, and he puts in what 
 he can buy for comparatively little money. 
 Q. Hoiv do you mean ? 
 
 A. I mean that if I sell my oats and hay, I get a 
 
 much higher price for them than 1 afterwards give when 
 
 I buy tliem back again in the form of horse dung. 
 
 Q. Then the farmer can really afford to pat as much 
 
 upon his land as he takes off, and yet have a profit ? 
 
 A He can. He puts in what is cheap, and takes oCF 
 what is dear. 
 
CHEMISTRY AND GEOLOGY. 45 
 
 The teacher may avail himself of this occasion to point 
 out how beaulifully anil bountifully the eaith anil Iho 
 plant are maile to work into the hands of the practical 
 farmer, by converting into valuable produce what he 
 lays on in the form of a worthless refuse — and how they 
 always do most for the skilful, the prudent, and the in- 
 dustrious. 
 
 Q. JVIiat do you call the substances which the skilful 
 farmer thus puts into his land ? 
 A. Tlicy are called manures, — and when putting them 
 in, tlie farmer is said to manure his soil. 
 
 VI. — OF THE MANURING OF THE SOIL.. 
 
 Q. JVhat is a manure ? 
 
 A. Any thing lliat furnishes food to plants may be 
 called a manure. 
 Q. How many principal kinds of manure are there ? 
 
 A. There are three principal kinds,- — vegetable ma- 
 nures, animal manures, and mineral manures. 
 Q. What do you mean by vegetable manures ? 
 
 A. By vegetable manures, I mean those parts of 
 plants which are usually buried in the soil for the pur- 
 pose of making it more productive. 
 Q. Name the most important of the vegetable ma- 
 nures. 
 
 A. Grass, clover, straw, hay, potato-tops, rape-dust, 
 &c. 
 Q. Is green grass ever used for manuring the soil ? 
 
 A. Yes, the soil is manured with green grass, when 
 grass land is ploughed up. 
 
46 CATECHISM OF AGRICULTURAL 
 
 Q. fVould you bury the sods deep if you were ploughing 
 up grass land ? 
 
 A. No, I would keep the sods so near the surface that 
 the roots of the young grain could feed upon the de- 
 caying grass. 
 
 Q. jire any other plants ploughed in green for the pur- 
 pose of manuring the soil ? 
 
 A- Yes, clover, buck %¥heat, rape, rye, and in some 
 places even young turnips are ploughed in green to en- 
 rich the soil. 
 
 Q. Into what kind of soils would you plough in a green 
 crop ? 
 
 A. Into light and sandy soils, and into such as contain 
 very little vegetable matter. 
 Q. Is not sea weed or sea- ware a very valuMc manure ? 
 
 A. Yes, wherever sea-weed can be obtained in large 
 quantity, it is found to enrich the soil very much. 
 Q. How is it employed 1 
 
 A. It is either spread over the land and allowed to rot 
 and sink in, or it is made into a compost, or it is put in- 
 to the potato drills in the fresh state. 
 Q. When used in this last way does it give large crops 
 oj potatoes ? 
 
 A. Yes, on the east and west coasts of Scotland it is 
 said to give large crops of potatoes, but of inferior 
 quality. 
 
 Q. How would you prefer to make a compost of sea- 
 weed ? 
 
 A. I would mix the sea-weed vfith earth and with 
 
CHEMISTEY AND GEOLOGY. 47 
 
 shell-sand or marl, if they were to be had, and turn it 
 over once or twice before using it. 
 
 Q. Are there any common f;reen vegetables that art 
 ploughed in with advantage I 
 A. Yes, potato-tops dug in, or turnip-tops, when the 
 roots are pulled, make the next year's grain better. 
 Potato or lurnip lops ploughed in make the succeeding 
 barley or wheat crop so much belter, that, about Edin- 
 burgh, the turnip tops are reckoned equal to 8 tons of 
 farm-yard manure, or £2 an acre. It is said, however, 
 that the clover which succeeds the grain is worse when 
 (he tons have been ploughed in, — that it is sicklVj and 
 sometimes fails altogether. 
 Q. Hoxv can you get the largest quantity of green ma- 
 nure in the form of potato-tops ? 
 A. By pulling off the blossoms, the tops are kept in 
 a green state till the potatoes are dug up, and thus give 
 much green manure. 
 
 Q. In what form is hay usually employed as a manured 
 A. Hay is usually given to the stock, and afterwards 
 put upon the land in the shape of their dung. 
 Q. In what form is straw used as a manure ? 
 
 A. Straw in some places is given to the cattle — in 
 other places it is partly given to the cattle and partly 
 trodden among the litter — wUile in places again, where 
 few cattle are kept, it is sometimes rotted with water 
 and a little cow dung, and put on the land in a half-fer- 
 mented state. 
 
 Q. In what state of fermentation would you prefer put- 
 ting your straw into the land ? 
 A. That would depend upon the kind of land. 
 
^ CATECHISM OF AGKICULTURAL 
 
 Q. Suppose 1/ow had to manure light land for a green 
 crop ? 
 
 A. Then I would like to have my straw pretty well 
 fermented and mixed with the droppings of a good ma- 
 ny cattle. 
 
 Q. £ut suppose you, icere manuring heavy clay land 
 during the naked fallow before a crop of iL>heat ? 
 
 A. I would then rather have my straw more loose and 
 unfermented. It would help to keep my land open. 
 
 This general nile may not apply to all even of our heavy 
 clay lands. Even stiff clays vary in quality, anil circum- 
 stances may render inexpedient in some localities what, 
 as a general practiccj is the best that can be recommen- 
 ded. 
 Q. What are rape-cake and rape-dust ? 
 
 A. Rape-cake is the refuse that remains when rape- 
 seed is crushed in the mill to squeeze out the oil. When 
 Ihe cake is crushed it is called rape-dust. 
 Q. Now is rape-dust applied as a manure ? 
 
 A. It is applied to turnips or potatoes either in place 
 of the whole or of a part only of the common farm- 
 yard dung — and it is in many parts of the country ap- 
 plied with great profit as a top-dressing to the young 
 wheat in spring. 
 Q. What are the most important animal manures 1 
 
 A. The blood, flesh, bones, hair, wool, and the dung 
 and urine of animals, and the refuse of fish. 
 Q. In li hat form is blood usually employed as a vianure t 
 
 A. In this country it is usually mixed up with other 
 refuse in the dunghills of the butchers. In other coun- 
 
CHEMISTRY AND GEOLOGY. 49 
 
 tries it is dried and applied as a top-dressing, or drilled 
 in with the seed. It is one of the most powerful ma- 
 nures. 
 Q.. How is flesh employed as a manure 1 
 
 A. The ilesh of dead horses, cows, and dogs buried 
 in soil or saw dust, with a little marl, makes a most en- 
 riching compost. 
 
 Q. In what form are bones usually employed as a ma- 
 nure ? 
 
 A. Bones are crushed in mills, and then sifted into 
 the various sizes of inch bones, half-inch bones, and 
 dust. 
 Q. In which of these forms do they act most quickly! 
 
 A. They act most quickly in tlie form of dust, but 
 tliey do not act for so long a time. 
 Q. To what crops are they most usually applied ? 
 
 A. Bones are most profitably employed on light or on 
 well-drained lands, instead of the whole or of a part of 
 the farm-yard manure. When employed without farm- 
 yard manure, they are often mixed with wood ashes, 
 and drilled in with Ihe turnip seed. 
 
 Q. Would you raise all your turnip crops with bones 
 alone ? 
 
 A. No, if I raised one crop of turnips from bone* 
 alone, I would raise the next crop on the same field witk 
 farm-yard manure alone — if I could get it. 
 Q. ^re bones ever applied to grass lands ? 
 
 A. Yes, to grass lands that have long been pastured 
 by growing stock, or for dairy purposes, as in Cheshire, 
 they have been applied with great profit. Even when 
 
60 CATECHISM OF AGRICULTURAL 
 
 the grass lands are wet, the bones have produced re- 
 markable benefits. 
 Q. What do hones consist of! 
 
 A. Bones consist of glue or gelatine, which maybe 
 partly extracted by boiling them in water — and of bone- 
 earth, which remains behind when bones are burned. 
 
 Here the teacher may burn a small splinter of bone in the 
 flame of a lamp or canille, anil show that though the 
 organic part (the gelatine) burns away, the inorganic 
 part or bone-earth (phosphate of time) remains behind. 
 Q. Is the glae ot gelatine of bones a good manure ? 
 
 A. Yes, it is a powerful manure. It assists very 
 much in pushing; forward the youn.: turnip plant, when 
 this crop is raised by the aid of bones. 
 Q. What docs bone-earth o^ phosphate of lime consist of! 
 
 A. It consists of phosphoric acid and lime. 
 Q. Does this earth of bones act as a manure 1 
 
 A. Yes, because all plants contain, and therefore re- 
 quire for their healthy growth a certain quantity of lime 
 and phosphoric acid (see above, Table I. p. 38, and III. 
 p. 43.) 
 Q, Why do old dairy pastures especially require bones ? 
 
 A. Because milk and cheese contain bone-earth, and 
 
 . if these be carried away and sold off the farm, the land 
 
 is robbed by degrees of this bone-earth, more tlian of 
 
 »ny other substance. Only those grasses can then grow 
 
 which require little bone-earth. 
 
 Every ten gallons of milk contain about half a pound of 
 bone-earth. A cow, therefore, which gives twenty 
 quarts a-day, takes about two pounds of bone-earth from 
 
CHEMISTRY AND GEOLOGY. 51 
 
 the soil every week. To return these two pounjs to the 
 soil three pounds of bone-dust are required. 
 Q. jlnd what effect follmes from adding the bones 1 
 
 A. The bones supply the bone-earth of which the 
 land had been robbed. New grasses then spring up 
 which contain much bone-earth, and these, when eaten 
 by the cow, produce milk in greater abundance and 
 richer in cheese. 
 Q. ^re bones applied in any other form ? 
 
 A. Yes, they are sometimes dissolved in sulphuric 
 acid (oil of vitriol.) 
 Q. How do you dissolve bones in sulphuric acid ? 
 
 A. About equal weights of bone-dust and of acid are 
 taken. Tlie acid is diluted with three times its bulk of 
 water and poured upon the bones, and the mi.xture is 
 stirred occasionally for two or three days. 
 
 The teacher may show how this is done, and explain that 
 the liquid oblained may either be further diluted with 
 thirty times its bulk of water and applied with a water- 
 cart, or may be dried up with powdered charcoal, peat, 
 saw-dust, or soil, and drilled in as bones usually are. 
 The relative proportions of bones anil acid may also be 
 varied. 
 Q. What is the advantage of thus dissolving the bones ? 
 A. One of the chief advantages is, that the substan- 
 ces of which the bones consist are very miniitely divi- 
 ded. They can thus enter more readily into the roots 
 of plants, and a smaller quantity produces an equal effect 
 upon the crop. 
 Q. Is hair much used as a manure ? 
 
 A. No, hair is generally too expensive to be used as 
 
52 CATECHISM OF AGRICULTURAL 
 
 a manure. But in China, where the people's heads are 
 all shaved, the shavings are collected lor manure, and 
 the sweepings of our hair-cutters' rooms might be also 
 employed with profit. 
 Q. In what form is wool used us a manured 
 
 A. In the form of woollen rags. Mixed with earth, 
 woollen rags make an excellent compost. They are 
 much used for manuring the hop grounds. 
 
 The teacher may here ilesciibe the hop plant, and explain 
 the purpose for which it is grown and employed by the 
 brewers. 
 
 Q. What kinds of animal dung are most commonly 
 employed as manures ? 
 
 A. Night-soil, horse dung, cow dung, slieep's dung, 
 pigs' dung, and birds' dung. 
 Q. IVhich of these is the most valuable ? 
 
 A. In general, night-soil and birds' dung are Ihe most 
 valuable; next, horse dung; after that, pigs' dung, and 
 lastly, cow dung. 
 Q. H'hy is night-soil so valuable ? 
 
 A. Because men generally live upon a mixture of 
 animal and vegetable food, which renders Ihe dung 
 richer. 
 
 Q. Why is the solid part of horse dung richer or hotter 
 than cow dung ? 
 
 A. Because the horse void -^ little urine compared with 
 the cow. 
 Q. IFhat IS the principal objection lousing pigs' dungi 
 
 A. The disagreeable smell and taste it is said to give 
 to the crops raised from it. 
 
CHEMISTRY AND GEOLOGY. 53 
 
 Q. fVhat is the best way of using pig's dung 1 
 
 A. The best way is to make it into a compost, or to 
 mix it with the dung of other animals. 
 Q. Wliy is cow dung colder and less liable to fermeiU 
 than most other kinds of dwng ? 
 
 A. Because the large quantity of urine voided by the 
 cow, carries off a great proportion of that which would 
 otherwise tause it to ferment. 
 
 Q. In what respect does the mixed dung of animals dif- 
 fer from the food on which they live ? 
 
 A. It differs principally in containing a less propor- 
 tion of carbtin, and a greater proportion of nitrogen than 
 the food they have eaten. 
 Q. How comes it to contain less carbon ? 
 
 A. Because animals throw off a large quantity of the 
 carbon by their breathing. 
 
 Q. In what form does the carbon of the food come off 
 from the lungs during breathing ? 
 
 A. In the form of carbonic acid gas, (see figs. 9 
 and 10.) 
 
 Q. //oi« much carbon does a man give off in this form 
 from his lungs in a day. 
 
 A. A full grown man gives off about half a pound in 
 a day, and a cow or a horse eight or ten times as much. 
 Q. Does all the nitrogen of the food remain in the 
 mixed dung and urine of animals ? 
 
 A. Yes, nearly all the nitrogen remains — mixed with 
 a smaller quantity of carbon than was in the food. 
 Q. Is this larger proportion of nitrogen the cause of 
 the greater activity of the dung of animals ? 
 
 A. Yes, it is one of the principal causes. 
 
54 CATECHISM OF AGRICULTURAL 
 
 Q. What form does this nitrogen assume during the 
 fermentation of animal manures ? 
 
 A. It assumes, foi the most part, the form of am- 
 monia. 
 Q. ff^hat is ammonia'? 
 
 A. Ammonia is a kind of air which has an exceed- 
 ingly strong smell, — the common hartshorn of the shops 
 is merely water impregnated with this gas. 
 
 Here the teacher may exhibit a bottle of tiartshorn or of 
 smelling salts, (carbonate of ammonia.) and nial^e his pu- 
 pils acquainted with ttie smell of ammonia. 
 Q. Under what circumstances is aminonia produced 
 naturally ? 
 
 A. It is produced in fermenting compost or manure 
 heaps, and in fermenting urine, and ii is the cause of the 
 smell perceived in hot stables. 
 Q. How can you detect the presence of this ammonial 
 
 A. By dipping a rod or feather in vinegar, and holding 
 it over the dung heap or in the stable, when, if ammonia 
 is present in the air, white fumes will become visible. 
 
 Here the teacher will show this experiment, by dipping: a 
 glass rod or feather into vinegar, or into muriatic acid, 
 and holding it over the mouth of his hartshorn bottle, 
 when white fumes will become visible, showing that 
 ammonia is escaping in the form of gas 
 
 Q. What does ammonia consist of? 
 
 A. Ammonia consists of the two gases, nitrogen and 
 hydrogen. 
 
 14 lbs. of nitrogen and 3 lbs. of hydrogen, make 17 lbs. of 
 ammonia. 
 
CHEMISTRY AND GEOLOGY. 55 
 
 Q. How does this ammonia enter into the roots of plants, 
 when it is formed in the manure 7 
 A. It is dissolved in the soil by water, and is then 
 sucked in by the roots. 
 
 Q. What substances are formed in plants by the aid of 
 this aninumia ? 
 A. The glulen and other substances containing nitro 
 gen are formed by the aid of this ammonia. 
 Q. Is this ammonia, then, a very important ingredient 
 in the manures 1 
 A. Yes, because nitrogen, in some shape or other, is 
 absolutely necessary to the growth of plants. 
 Q. In which part of the manure, — the solid or the liquid 
 part, — is this ammonia produced in greatest abun 
 dance ? 
 A. It is produced in the greatest abundance in the li- 
 quid part, especially of cow dung. 
 
 Q. Is it 7iot of great importance, therefore, to preserve 
 this liquid part ? 
 A. Yes, it is of the greatest possible importance, 
 though it is too often allowed to run to waste. 
 Q. How would you collect the liquid manure of your 
 farm-yard ? 
 A. I would make a large tank or cistern in or close by 
 my farm-yard, in which I would collect it. 
 Q. How would you use this liquid manure ? 
 
 A. I would pump it back occasionally upon my dunj^ 
 heaps, so as to promote their fermentation; or I would 
 pour it upon ray compost heaps. 
 Q PFould you not employ it alone as a manure ? 
 
 A. Yes, during the spring and summer I would dilute 
 
66 CATECHISM OF AGRICULTURAL 
 
 it with once or twice its bulk of water, and after it had 
 fermented for some time, I would put it on my grass 
 land, on my young clover, or on any other young crops, 
 with a water cart. 
 
 Q. Is there ajiy other liquid containing ammonia which 
 might be einphiyed in a similar wayl 
 
 A. Yes, the amaioniacal liquor of the gas works, di- 
 luted with four or five times its bulk of water, should be 
 coliecled and employed in the same way as the liquid 
 manure of the farm yard. 
 Q. Does birds' dang form a very valuable manure 1 
 
 A. Yes, pigeons' dung especially, is a very rich ma- 
 nure; and the dung of sea-fowl has lately been intro- 
 duced into this country, with great advantage, under the 
 name of guano. 
 Q. To what crops can guano be profitably applied ? 
 
 A. It may be profitably employed as a top-dressing 
 to the young corn crops, or it may be used instead of 
 the whole or of a part of the farm-yard dung, for the 
 turnip and potato crops. 
 
 Q. In using it for the turnip or potato crop, ought it to 
 be allowed to come in contact with the seed ? 
 
 A. No, it is better either to cover it, or to mix it with 
 a quantity of earth, so as to prevent the seed from touch- 
 ing it. 
 Q. Is it proper to mix guano with quicklime. 
 
 A. No, because the quicklime sets free the ammonia 
 contained in the guano, and causes it to escape into the 
 air. 
 
 Here the teacher may mix a little slaked lime with a 
 
CHEMISTRY AND GEOLOGY. 67 
 
 spoonful of guano in a wine-glass, anil let his pupils 
 smell the ammonia which will come oif. Or he may 
 hold over it a rotl or feather ttipped in vinegar, and show 
 the white fumes. If he have no guano, he may use a 
 little sa/-aOTnio;iiac or a little sulphate of ammania instead; 
 and may explain that quiclc-hmc will, in the same way, 
 drive ofif ammonia contained in liquid manure and in 
 horse or farm-yard dung, if it be mixed with any of 
 these. 
 
 Q. Is it better to use gaano alone, or in place of one- 
 half only of the usual farm-yard manure ? 
 A. It is better husbandry to use it in raising turnips 
 
 and potatoes, mixed witli one-half manure. 
 
 Q. fVhy is it better husbandry ? 
 
 A. Because the guano used alone, does not supply to 
 
 the land a sufficient quantity of organic matter to main- 
 lain it in the most productive state. 
 
 Q. HoiB much guano would you apply per acre ? 
 
 A. About two cwls. per acre as a top-dressing for the 
 
 corn crops, and two or three cwts., when used instead 
 
 of half the dung, for potatoes and turnips. 
 
 Q. What kind offish refuse is usually employed as a 
 manure? 
 A. In the curing stations the guttings and cleanings 
 
 of the herring and pilchard, and the heads of the cod are 
 
 extensively employed as a manure. 
 
 Q. How is this refuse best used ? 
 
 A. The best way is to make it into a compost with 
 
 earth and a quantity of marl, if any of the latter is at 
 
 hand, and to turn it over once or twice before using. 
 
 Q. Name the most important mineral manures'! 
 
58 CATECHISM OF AGRICtJLTUKAL 
 
 A. The most important mineral manures, are nitrate 
 of soda, sulphate of soda, common salt, gypsum, kelp, 
 wood ashes and lime. 
 Q. What is nitrate of soda ? 
 
 A- Nitrate of soda is a white salt-like (saline) sub- 
 stance, which is found in the earth in some parl^ of Pe- 
 ru, and is often applied with great advantage as a top- 
 dressing to grass lands and to young corn. 
 Q. What does nitrate of soda consist oft 
 
 A. It consists of nitric acid and soda. 
 
 54 lbs. of nitric acid, and 31 lbs. of soda, form 85 lbs. of 
 nitrate of soda. 
 
 The teacher may lake this opportunity of verbally explain 
 ing the kinil of (erms by which chemists denote combi 
 nations of the nitric, sulphuric, phosphoric, and carbonii 
 acids with potash, soda, lime, and magnesia, — that when 
 carbonic acid combines with any of these substances it 
 forms a carbonate, phosphoric acid a phosphafc, sulphu- 
 ric acid a sulpha<c, nitric acid a nilrafc. Hence, that 
 phosphate of lime denotes a combination of phosphoric 
 acid with lime, sulphate of soda, a combination of sul- 
 phuric acid with soda, and so on. 
 
 Q. What is intric addl 
 
 A. Nitric acid is a very sour corrosive liquid, called 
 also aquafortis. It consists of the two gases, nitrogen 
 and oxygen. 
 
 14 lbs. of nitrogen and 40 lbs. of oxygen form 54 lbs. of 
 nitric acid. 
 Q. Upon what does the beneficial action of nitrate of 
 soda upon plants depend ? 
 
CHEMISTRY AND GEOLOGY. 59 
 
 A. Upon its supplying nitrogen and soda to the grow- 
 ing crops. 
 Q. What quantify would you lay upon an acre ? 
 
 A. From 1 cwt. to Ij cwt. to an acre. 
 Q. What is sulphate of soda? 
 
 A. Sulphate of soda is the substance commonly called 
 glauber salts, and consists of sulphuric acid {oil of vit- 
 riol,') and soda. It sometimes produces good effects 
 when applied as a top-dressing to grass lands, to turnips, 
 and to young potato plants. 
 
 40 lbs. of sulphuric acid with 31 lbs. of soda, form 71 lbs. 
 of dry sulphate of soda. 
 Q. How is common salt applied ? 
 
 A. Common salt may either be applied as a top dress 
 ing, or it may be mixed with the farm yard or other 
 manure, or with the water used in slaking quicklime. 
 Q. In what places is salt most likely to be beneficial ? 
 
 A. In places that are remote from the sea, or are shel 
 tered by high hills from the winds that pass over the sea. 
 Q. How do you account for this? 
 
 A. Because the winds bring with them a portion of 
 the sea spray, and sprinkle it over the soil to a distance 
 of many miles from the sea shore. 
 Q. ffliat is gypsum ? (plaster ?) 
 
 A. Gypsum is a white substance, composed of sul 
 phuric acid and lime; it forms an e.xcellent lop dres- 
 sing for red clover, and also for the pea and bean crop. 
 
 40 lbs. of sulphuric acid and 28 1-2 lbs. of lime form 
 68 1-2 lbs. of burned gypsum. 
 
 40 lbs. of acid, 28i lbs. of lime, 18 lbs. of water, form 
 
60 CATECHISM OF AGRICULTURAL 
 
 86| lbs. of unburnetl gypsum. Native or unbiirneil gyp- 
 sum loses about 21 per cent of waler when healed to 
 dull redness, becoming burned gypsum. 
 Q. Under what circumstances ouglU tliese sail-like or 
 saline substances to be applied ? 
 A. They ought to be applied in calm weather, in or- 
 der (hat they may be equally spread, — and soon after or 
 before rain, that they may be dissolved. 
 Q. jfre mixtures of these substances sometimes more 
 beneficial than any of them applied singly ? 
 A. Yes, a mixture of nitrate and sulphate of soda 
 usually produces a much more beneficial eflfect upon 
 potatoes than either of them alone, and the same is often 
 the case with a mixture of common salt and pypsuni 
 when applied to the bean crop. 
 
 The teacher will find some useful particulars upon this 
 point in the author's Elements of Agricultural Chemistry 
 and Geology, (fourth Edition, page 194), which he may- 
 consult with advantage, with the view of explaining the 
 subject more fully to his pupils, when he shall think it 
 proper to do so. 
 Q. What is kelp ? 
 
 A. Kelp is the ash that is left when sea-weed is burned 
 in large quantities. 
 Q. Can it be employed usefully as a manure ? 
 
 A. Yes, as a top dressing to grass lands and to young 
 grain — or even mixed with the manure for the turnip 
 and potato crop it may be employed with much advan- 
 tage. 
 
 Q. Has it been generally employed as a manure in Scot- 
 land! 
 
CHEMISTRY AND GEOLOGY. 61 
 
 A. Not hilherto, but there is reason to believe that, 
 if fairly tried, it might be jirofitably employed to a large 
 extent. 
 
 Q. Are woud ashes (^or the ashes of burned mood) a 
 valuable manure ? 
 
 A. Yes, sipplied to grass lands wood ash destroys 
 moss, and increases their luxuriance: upon young grain 
 and potatoes it produces a similar effect, and is profita- 
 bly mixed with bones, rape-dust, guano, and other ma- 
 nures which are employed for the turnip crop. 
 Q. What does limestone consist of! 
 
 A. Limestone consists of lime (juicfc-lime) in com- 
 bination with carbonic acid. 
 
 28 lbs. of lime and 22 lbs. of carbonic acid make SO Ibi. 
 of limestone. 
 
 The teacher may here revert (o the properties of carbonic 
 aciii, and examine his pupils upon what they had previ, 
 ously learned upon this subject. 
 Q. JVhat name is given to limestone by chemists ? 
 
 A. It is called by chemists carbonate of lime. 
 Q. jire there not many varieties of limestone ? 
 
 A. Yes, — some soft, such as chalk, — some hard, such 
 as our common limestones, — some of a yellow color, 
 like the magnesian limestones, which contain mag- 
 nesia, — some pure white, like the statuary marble, — 
 some black, like the Derbyshire black marble, and so on. 
 
 Here it wouhl be advantageous if the teacher could exhibit 
 some of these or of other varieties of limestone. 
 Q. JVhat is marl ? 
 
 A. Marl is the same thing as limestone, namely, car- 
 
62 CATECHISM OF AGRICULTCRAL 
 
 bonate of lime, only it is often in the state of a fine 
 powder, and often also mixed with earthy matter. 
 Q. IVhat is shell sand 1 
 
 A. Shell sand or broken sea-shells is also the same 
 tiung, almost exactly, as common limestone. 
 Q. Can these marls and shell sands be applied with ad- 
 vantage to the land ? 
 
 A. Yes, either as a top-dressing to grass lands, and 
 especially to sour, coarse, and mossy grass, — or they 
 may be ploughed or harrrowed in upon arable fields, — 
 and especially they may be applied with advantage and 
 in large quantity to peaty soils. 
 Q. Can they not be used also in making composts 7 
 
 A. Yes, mixed with earth and vegetable matter, or 
 with animal matter, such as fish refuse, whale blubber, 
 &c., and even with farm-yard dung, they will often pro- 
 duce very good effects. 
 
 Q. How would you ascertain the presence of lime in a 
 soil or in a substance supposed to be a marl ? 
 
 A. By putting a little of it into a glass and pouring 
 upon it either vinegar or weak spirit of salt (murialic 
 acid.) If any bubbling up (effervescence) appeared, I 
 should say that lime was piesent. 
 Q. To what would this bubbling up be owing .' 
 
 A. It would be owing to the escape of carbonic acid 
 from the carbonate of lime which the soil or marl conr 
 tained. 
 
 Here the teacher may perform this experiment by pour- 
 ing weak acid upon marl or powilereil chalk in a wine 
 glasSj and showing the bubbling up. He may further 
 
CHEMISTRY AND GEOLOGY. 
 
 63 
 
 convince his pupils that the gas given off is really car- 
 bonic aciJ, by introducing a lighted taper into the glass 
 when it will be extinguished. (See fig. 2.) 
 Q. fFhat takes place when limestone {carbunate of lime) 
 is bamcd in the kiln ? 
 A. The carbonic acid is driven ofl' from tlie IIm&- 
 slone by the heat, and the lime alone remains. 
 Q. jyhat is the lime called iri this state ? 
 
 A. It is called burned lime, quick-lime, caustic lime, 
 hot lime, lime shells, &c. 
 
 Q. What weight of quick-lime or lime-shells is obtaintd 
 from a ton of limestone 7 
 
 A. A ton of limestone yields about 11 J cwts. of quick- 
 lime. 
 
 Q. fVhat takes place when water is poured upon quick- 
 lime ? 
 A. The quick-lime drinks in the water, becomes 
 very liot. shells up, and 
 gradually falls to pow- 
 der. 
 
 The teacher may ex- 
 hibit this effect of 
 water upon lime, 
 and may satisfy his 
 pupils that the heat 
 produced is great, by showing that it will sometimes sel 
 fire to gunpowder placed upon a dry portion of the lime, 
 or will heat a cold, baked pie, when put in Ihe middls 
 of it. He may also explain to them that it is the heal 
 thus given off which occasionally sets lire to the sod wiUt 
 
€4 C-1TECHT5JI or ACXKClTnAI. 
 
 vkich bea{is of Une-ifaidls arc 
 
 Q. rr&^ is tkia ptmriag ofw^er «pM iuK, w a to 
 
 A. h b asoallj called siakn^ the loBe. aDid ^Ome 
 isealkd daked or ^firfrrd lime. 
 Q. J)aa the qmfHimf iacraua ni ma^ miat tf-'r~i f 
 
 A. Tes: eae taa of pne qoickliaae beeooKS SSots, 
 •TrfdxdliBe. 
 
 f^ed to {&E atr ? 
 A. Tes, it xbeocfas water 6«b the air, aad gndaDf 
 hUs to powder. 
 
 Q. /)tes ^ci£ae Aiajkai(sfa0r&)cBjtta5'eiae,^raaa 
 tiemrl 
 A. Tes, it griilaillT driaks ia caiboEic acid frosfte 
 Br, and recons at le^& to ike stafe of nrfriitfr 
 
 Tbe teaeiur b^ hoe nP-'' i 
 
 flhas a&soc^ eacteaie aca< L.' . 
 Helii ■ ifi I- iaeoa tariil;- 
 Bootible filia of wkiee c^ 
 
 tarma on ks iiiafii i T>'< 
 teil farcke pocpose : 
 eaaboaTe aeM esiss 
 
 apoa qaiefcl - 
 
 ^■i>!k>wf2j 
 
 u it jiiTj- - 
 A. Yes .. _-. 
 
CHEWIETBY AMI CEOLOCT. M 
 
 C4XiU be g<o( bj any other me»ni, and can ibus l/» ^t.'jt* 
 tboroa^il}' mixtd wUb (b« w/iJ. 
 
 Q. ffAot i( t/ unuUly calUd xeken it hat thut rditnui 
 to the state of a carUm-iite 1 
 
 A. ]l u uKuail/ called mild lime, \a dittiag^udi it 
 from the quick or cauctic Ime. 
 
 Q. Doe$ qu.v:k-Umt act in a different leey upon Hut 
 land JTvm mild km* f 
 
 A. It acu very luucb ia ti>e lanie way, but mora 
 ««ii<.kly. 
 ^ Houi do tKey both act ? 
 
 A. Tbey act by supplying: (be lin»e »Li'.b all planto 
 require ai part of ibeir food, — by cottibiiujug «iil> acid* 
 in ibe toil, xi at lo remore the tourtkete of Ibc UmJ, — 
 aod by C4>0Terting tbe vegetable tiiaUer iulo the food ol 
 pUolf. 
 
 Q. Would you burn lime de^f, or vxnUd you kuf -.1 ntar 
 tht tMrJact 1 
 
 A- I would alarayf keep it oear tbe tmiiuot, ae it bu 
 k natml teodeticy to sink. 
 
 Q. TV tehof fon^ tocmU yov ofply qtick-Hau rallurr iKam 
 miUUmel 
 
 A. I would apply qtack-fime to pealy soils, to heai7 
 day Kiilt, to arable laadf wbich are very Kour, and 19 
 Rjcb »t cODlaiii a ;^reat deal of vegetable matler. 
 Q. fVili tke aame tjwmtity of limu ff*4mcf tin aaaM •* 
 a greater effect livon dratrud than vftrri v>tt land 1 
 
 A. Tbe nnte <}tianlilT will prodoce a gT<«t*r eflaci 
 ■poD draawd or MtanBy dry fand, tiMw upon wet UnA 
 5 
 
66 CATECHISM OF AGRICtTLTtJRAL 
 
 Q. Would you apply lime in large doses at long inter- 
 vals, or in small doses at shorter intervals ? 
 A. 11 I applied a large dose of lime at (lie beginnings 
 of my lease, I would apply smaller doses at the end of 
 each rotation, or at the end of every second rotation, to 
 keep up the quantity of lime in the land. 
 
 The teacher may tiere explain the meaning of the ne\r 
 word rotation, and may illu^itrate it by reference to the 
 course of cropping in his own or neighboring districts ; 
 and if he make himself master of the theory of rota- 
 tions (see the Author's Licturts on Agricultural ChemiS' 
 try and Geology, page 717,) he may give his pupils 
 correct notions upon this subject, which they will seldom 
 forget in after life. 
 Q. Why does liiiie require to be repeated ? 
 
 A. Cliicfly for three reasons: ^rs^, because the crops 
 cat up and carry off a portion of the lime; second, be- 
 cause a poition of it sinks into the subsoil; and thirdly, 
 because the rains are always washing a portion of it out 
 of the land. 
 
 VII. — OF THE COMPOSITION OF THE CROPS 
 WHICH THE FAR31ER REAPS. 
 
 Q, Of what substances do the difftrent kinds of grain 
 
 usually consist ? 
 . A. They consist chiefly of three substances, starch, 
 gluten, and oil or fat. 
 
 Q. IVhat proportion of each of these usually exists in 
 wheat 7 
 A. 103 lbs. of wheat flour contain about 50 lbs. of 
 ctarch, 10 lbs. of gluten, and 2 or 3 lbs. of oil. 
 
CHEMISTRY AND GEOLOGY. 67 
 
 Q. In what proportion do they exist in oats ? 
 
 A. 100 lbs. of oats contain about 60 lbs. of starch, 18 
 lbs. of gluten, and 6 lbs. of oil. 
 Q. JVhat do potatoes and turnips principally consist oft 
 
 A. Tlieir principal constituent is water. 
 Q. Hoii muchioateris contained in 100 /6s. of potatoes'! 
 
 A- 100 lbs. of potatoes, contain about 75 lbs. of wa- 
 ter. 
 Q. ffow much water is contained in 100 Ihs. of turnips ? 
 
 A. 100 lbs. of turnips contain about 88 lbs. of water. 
 Q. IVhat quantity of starch do potatoes contain ? 
 
 A. 100 lbs. of potatoes contain from Ij to 20 lbs. of 
 starch. 
 
 Q. jfre the^e proportions of starch, gluten, Sfc. always 
 the same in the same grain or root ? 
 
 A. No. Some varieties of wheat contain more glu- 
 ten than others, some varieties of oats more oil than oth- 
 ers, and some varieties of potatoes more starch than 
 others. 
 
 Q. Have the soil and climate any influence upon the 
 proportions of these ingredients ? 
 
 A. Yes, the wheat of warm climates is said to contain 
 more gluten, and the potatoes and barley grown upon 
 liglit or well drained land, more starch. 
 Q. When grain or potatoes are burned, do they leavi 
 any inorganic matter or ash ? 
 
 A. Yes, they all leave a small quantity of ash when 
 burned. 
 Q. Of what does this ash consist ? 
 
 A. It consists of the phosphates of potash, soda, lime 
 
63 CATECHISM OF AGEICULTURAL 
 
 and magnesia, of common salt, and other saline sub- 
 stances. 
 
 The teacher may here explain more fully the composition 
 of this ash, by referring to his table, (III.) which exhi 
 bits the composition of the ash of (lifTereiit kinds of grain, 
 anit explaining that the ash both of corn am! of the ordi. 
 nary root crops, contains a certain quantity of all the 
 substances there mentioned, but that phosphoric acid, in 
 combination with potash, soda, magnesia and lime are 
 its Tnost important ingredients.* 
 
 VIII. — USES OP THE CROPS IN FEEDING. 
 
 Q. JVhat natural purposes are vegetables intended to 
 serve! 
 A. They are chiefly intended for the food of animals. 
 Q. fVhat substances must an animal derive from its 
 food, that it may be maintained in a healthy stale ? 
 A. It must obtain starch, gluten, oil or fat, and saline 
 or inorganic matter. 
 Q. Do you recollect what starch co/isists of! 
 
 A. Starch consists of carbon and water. 
 Q. Ihr what purpose does an animal require starch in 
 itsjood ! 
 A. It requires starch to supply the carbon which it 
 throws off from its lungs during respiration. 
 
 The teacher may here explain that gum and sugar, which 
 
 * It will be perceived that there is inserted no account of the composition 
 of Indian com ; this is because there has been as yet, no complete anajyss 
 of it. It is my intention, in Prof, Johnston's Laboratory, and under his di- 
 rection, soon to commence an extended examination of tliia grain, .so im- 
 portant to our country.— J. P. Nobtom. 
 
CHEMISTEY AND GEOLOGY. 69 
 
 «l»o consist of carbon anj water only, (p. 27,) serve Iha 
 same purpose when eaten as (he starch of our food (loe«, 
 and that wliat is here said for simplicity of starch only, 
 is true also of the sugar and gum contained in the vege- 
 table substances we eat. 
 Q. Do you recollect how much carbon a man throws off 
 from his lungs in a day ? 
 A. Yes, he throws off from six to eight ounces in a 
 day. 
 
 Q. fVhat quantity of starch must he eat, in order to 
 supply the quantity of carbon given off from his 
 lungs in a day ? 
 A. He will require to eat nearly a pound of starch in 
 a day. 
 
 10 oz. of starch contain about 4^ of carbon, (p. 27.) 
 Q. In what form is the carbon given off from the lungs 
 of animals ? 
 A. It is given off in the form of carbonic acid gas. 
 Q. iVhat becomes of the carbonic acid gas thus given offt 
 A. It is diffused through the air, and afterwards ab- 
 sorbed again by plants, in order that new quantities of 
 starch may be produced from it. 
 
 The teacher may here appropriately draw the especial at- 
 tention of his pnpils to the beautiful cycle of natural ope- 
 rations here described. Even children may be made to 
 see the beauty and bounty of the processes by which the 
 same carbon is again and again transformed by the plant 
 into starch, and by the animal into carbonic acid — as well 
 as the purpose for which these changes are made to take 
 place — namely, (o keep up the warmth of the animal 
 body. 
 
70 CATECHISM OF AGHICTTLTUBAL 
 
 Q. Fbr what purpose does an animal require glutm, in 
 its food ? 
 
 A. An animal requires gluten for the pnrpose of re- 
 pairing the daily waste of the muscles or lean part of 
 its body. 
 Q. Are the muscles of an animal really subject to waste ? 
 
 A. Yes, nearly all the parts of the body suffer a cer- 
 tain waste every day. 
 Q. JVhat becomes of the part that thus wastes away 7 
 
 A. It is carried through the body, and forms part of 
 (he dung and urine of the animal. 
 
 Q. IJow can the gluten repair the waste of the musclet 
 or lean part of the animal? 
 
 A. Because the gluten of plants is exactly the same 
 thing as the muscles of animals. 
 Q. Why does the animal require oil or fat in its food ? 
 
 A. To supply the natural waste of fatty matter which 
 takes place. 
 Q. Does it serve any other purpose ? 
 
 A. Yes, when more is given than is necessary to sup 
 ply the waste it may make the animal fat. 
 Q. Is food that contains much oil, then, the best for fat 
 tening ? 
 
 A. Yes, of two samples of food that which contains 
 the most oil will fatten most quickly. 
 Q. Is this one reason why oil-cake is so good for fat- 
 tening stock ? 
 
 A. Yes, it is one reason. 
 Q. Jlliy must the food of animals contain phosphate of 
 lime and other inorganic matter 7 
 
CHEMISTRY AND GEOLOGT. 71 
 
 A. To supply the daily waste of the bones, of the 
 , ilts in Ihe blood, &c. 
 
 Q. Do not the gluten and the saline mutter serve a fur- 
 ther purpose when the animal is growing ? 
 A. Yes, when the animal is gfrowing; they not only sup- 
 ply the daily waste, but are daily adding to the weight 
 of the animal's body. 
 
 Q. TVill a growing atiimal on this account reqv.ire a 
 larger supply of these kinds of food ? 
 A. Yes, a growing animal of the same size will re- 
 quire more of these kinds of food than a full-grown ani- 
 mal. 
 
 Q. Suppose an equal quantity of food given to a grow- 
 ing and to a full-grown animal, which of them mil 
 give the richer dung ? 
 A. The full-grown animal will give the richer dung. 
 Q. Why so ? 
 
 A. Because the growing animal extracts and retains 
 more of the substance of the food. 
 Q. Why does it do this .' 
 
 A. Because it has both to supply the natural waste of 
 its own body, and to add to its size, wliile the full-grown 
 animal has only to supply the waste. 
 Q. Why is the dung (f fattening slock richer than that 
 of growing stock ? 
 A. Because fattening stock extract and retain only 
 the oil and starch of their food, and reject the remain- 
 der. 
 
 Q. I/ow would you convert a ton of oats or turnips into 
 the largest quantity of beef or mutton ? 
 
72 CATECHISM OF AGRICULTURAL 
 
 A. I would keep my callle or sheep in a warmer 
 sheltered place, — where they might have wholesome air, 
 and but little light. 
 
 Q. If you wanted merely to fatten a fullgrown beast, 
 what would you do ? 
 A. I would keep it warm, disturb it little, and give 
 it oil-cake or oats, with a good supply of turnips. 
 
 The degree of warmth ami confinement under which ani- 
 mals will thrive ilepenils much upon the breed. The 
 hardy and wild West Highlander would pineavay in the 
 warm and confined sheds in which the Teeswaler ox 
 thrives best, — and Ihe black-faced sheep would lose flesh 
 and become unheallhy where the delicate Leicester 
 would thrive and fallen. 
 Q. If you wished only to convert a large quantity of 
 hay, straw, or turnips into manure, what would 
 you do ? 
 A. I would put my stock into a cool and less sheltered 
 place, and 1 would make Ihem take a good deal of ex- 
 ercise; 
 
 Q. If you roished to make a cow give you the largest 
 possible quantity of milk, how would you f'.ed herl 
 A. I would give her rich juicy grass, turnips, brew- 
 er's grains, mashes, or other food containing much wa- 
 ter, — and I would supply her with drink when she would 
 take it. 
 
 Q. But to obtain mi'.k of the best possible quality, would 
 you do so ? 
 A. No. I would then give her as much dry food, — 
 oats, beans, bran and clover hay, — as she would eat 
 
CHEMISTRY AND GEOLOGY. 73 
 
 Q. If you rvanted milk particularly rich in butter, 
 what would you give ? 
 A. I would give ber the same kind of food as I would 
 to a fattening animal, — oil-cake, oats, bailey, Indian 
 corn meal, and some turnips. 
 
 Q. Hut if you were going to make cheese of your milk, 
 would you give the same kind of food J 
 A. I would then prefer beans, peas, vetches, and clo- 
 ver, or clover hay, all of which make the milk richer in 
 curd. 
 
 Q. j/s a general rule in fattening off milk cows or pigs, 
 would you give the food siveet or sour J 
 A. To pigs I would give it slightly sour, to fattening 
 cows and bullocks I would give it fresh and sweet. 
 
 In some of the great London dairies — as that of the Messrs. 
 LaycDcU at Islington — the brewers' grains are trodden 
 while hot into deep pits lined with brick, and covered 
 over with a layer of earth so as to exclude the air. Treat- 
 ed in this way, they are said to become more saccharine 
 and nutritive, anil are considered none the worse for be- 
 ing several years old. 
 
 Q. fVhy would you give it sour to pigs ? 
 
 A. Because it has been found that much more pork is 
 obtained from green vegetables, or from bean meal or 
 boiled potatoes, when mixed with water and left to sour, 
 than when given fresh and sweet. 
 
 Q. Is there any thing else you would do to make your 
 stockfeeding more profitable 1 
 
74 CATECHISM OF AGRICULTURAL 
 
 A. Yes, I would keep my cow houses well ventilated, 
 but warm, and my sheep and pigs clean; and I would 
 feed them at regular intervalsj and at least three times a 
 day. 
 
 While on this part of the subject, the teacher may draw 
 the attention of his pupils to the beautiful chemical coa- 
 necliun which exists between the vegetable and animal 
 kingiloms, anil especially to the marked adaptation of 
 the living vegetable to the wants of the living anima], 
 which is exhibited in the fact, that the animal finils ready 
 formed in the ripened plant, all the most important sub- 
 stances of which its own body iscomposeil. The gluten 
 is identical wiih the fibre of its muscles, the oil similar 
 in character with the fat of its body, while the bone 
 earth of the plant supplies materials for the bones of the 
 animal, and the starch and sugar atford the carbon which 
 is necessary for the purposes of respiration. Finally, he 
 may also point oul, that, when the vegetable fooii has 
 discharged its office in the animal boily, it returns to the 
 earth in the form of dung — only to enter into the roots 
 of new plants, and thus to produce new supplies of sus- 
 tenance fur oiher races of animals. The en'ire economy 
 of vegetable and animal life, and all the changes expe- 
 rienceil by dead matter, are parts of one system — ex- 
 press, as it were, but one idea, the offspring of ONX 
 MIND. 
 
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