

flIi:.Ml>TUV. 



[COMPOSITION or SOILS. 



Fat, oils, wax, Ac., are Urgnly used in the manufac- 

 ture of soap and candles by means of the process do- 

 fcnU-d in connection with stearine. This br:. 

 manufacture has . HH-I..I I of l.ito 



t" the stimulus which chemical discoveries hare 

 afforded. 



Bones and nrine are employed in the manufacture of 

 it, a substance which, a few years ago, was only 

 a chemical curiosity, but whic . resent day, is an 



absolute necessity (in tlie lucifer-iuatch) to, perhaps, 

 very emitted home in the w. . sizo, isinglass, 



patent gelatine, are each produced from skins or l-one ; 

 and r substance has become of considerable 



commcrvud importance in the manufacture of portable 

 soup*. V' . for the sake of our readers, to indi- 



cate iU possible sources iu many case*. 



Space fails us to name all the uses to which AIM 

 substances are now applied. Chemistry liri: 

 only to use up what won '1 . rwiaa bo waste, but 

 actually e.,iive;t<, in some cases, sul y as i 



: as iliri." and tv.-tl dirt, into others us valuable us , 

 gold. Indeed, it.s chiuf object, at tho present day, i 

 turn to profit tint which has been cast away as . 

 former times. Aniline, aluininuin, 

 products, afford u-< i I, and ; 



alike to the philosopher an 1 t ., ai'.-ia, t!i.it n.iiiin; 

 wax in i lo in v.iiu, or without its definite olij.-ct and use. 



\N hilst it is the province of science t m<l in- 



, the natural energy and in-tiii'-t of man tend to 



utilise ; and thus each succuedin.' >; builds its monu- 



ni'-iit on the d-'brit of that which preceded it, ouly to 



ail'ord materials for that which has to follow. 



CHAPTER XII. 

 CHEMISTRY APPLIED TO AGRICULTURE. 



\VITIU* the last few years chemistry has been extensively 

 employed m connection with agricultural pursuits. For 

 centuries, agriculture had been little else than a system 

 of conjecture and chance, in which the experience or 

 opinion of each fanner was followed, without reference 

 to principles or experiment. At the present time, on the 

 contrary, science becomes the guide of every homestead 

 the aid of chemistry is everywhere sought, and agri. 

 cultural societies and college* are the means of diasemi- 

 natin,' its t mmngst the masses. 



At first ni^tit it woiiM ,-eem that agricultural chemistry 

 is a subject so extensive, that an acquaintance with it 

 would involve almost a lifetime of research and expe- 

 rience . but such is not the case. We have simply to 

 learn the conMitiients of any plant, and we shall at once 

 perceive the nature of the soil required for its produc- 

 tion. Trie question of climate, period of sowing and 

 reaping, drainage, and similar matters, do not fall within 

 the scope of chemistry. Such are purely matters of 

 jn ijiuriit and experience, for which no science can be 

 substituted, except the knowledge acquired by repeated 

 a id kmc-ooqtinned observation. 



The chemist has to decide on the question of the com- 

 ponent parts of soils actually present, and the nature of 

 such which, whilst absent, may be supplied in the form 

 of manure. To do this, he carefully analyses the grain 

 which is to be sown, and the soil in which it is intended 

 to sow it ; and whatever the latter is deficient in, his 

 result should tend to point out, and to suggest a supply. 



Let us first examine into the most important of all kinds 

 of food, the cereals, such as wheat, rye, <tc. The ear of 

 wheat consists of seed, which is composed of gluten and 

 tarch. The latter substance is abundant in m <st plants, 

 especially in cereals, potatoes, Arc. It consists entirely 

 of carlivn, hydrogen, and oxygen,* whilst gluten has au 

 a/l'li form of nitrogen. But besides 



the Htan-h and uu-n, earthy matter of various kinds is 

 found in the seed and stem, such as silex, lime, it c. ; and 

 , whilst they act as the bone to the plant daring its 

 vi U i ...in. in the animal through the absorp- 



tion of tliiiMt MI I > unices iu the system from the vegetable 

 fd on which it subsists. It matters not whether animal 

 or v.-.e'.il.le food bo used by man, exclusively, or mixed 

 In either case he acquires the mineral matter 

 of which hu bones, teeth, ike., stand in need ; from the 

 plant directly, iu a crude state ; or from the animal, as 

 x ..n I sheep, in a form more readily adapted for as- 

 similation. Indeed, the domestic animals and plants 

 used as food are simply channels, by which the elements 

 of the soil are i m inanimate dust to the con- 



stituent* of sentient humanity. In this process, for a 

 only, inanimate nature U robbed of part of her own . 

 but this orcuni only for a brief space. Daily wo give 

 back, as excroU, portions of earthy and saline matter ; 



ftMMf*, p. 411. 



and, at last, when we return "dust to dust, ashes to 

 ashes," we repay the debt we have incurred during tho 

 brief period of our existence ; and our mortal bodies, in 

 their decay, literally and truly return to the earth from 

 which they were first made. Nothing is lost ; but, on the 

 contrary, the particles of matter undergo au incessant 

 change of combination flitting at one moment as dust 

 in the sunbeam, and anon forming the material of man, 

 made in God's own image. 



If we carefully examine the constituents of an average 

 soil, we shall find that their number is comparatively 

 few. The following is an analysis of one of tlie best 

 soils found in the grazing pastures of Devonshire and 

 Cheshire. It contains of 



Silica per cent. 



Alumina 



Carbonate of lime .... 

 e of iron 



Water and organic matter . . 



Chloride of sodium (common salt) 



702 



04 



6-0 



41 



1 



100.0 



Now the whole of the above ingredients go to form the i 

 solid matter of a plant, but only in part ; for i 

 proportion of flour, p. - of carbon and 



water, derived, not from the soil, but from the atmo- 

 sphere which surrounds the plant. 



When a seed commences to germinate it produces two 

 organs the root, or radicle, which is to inhabit the soil ; 

 and the plumule, which, rising beyond the soil into the 

 atmosphere, is to become the means by which the car- 

 bonic acid floating iu the air is to be absorbed, ami 

 carbon assimilated to the body of the plant. With this 

 part of the growth the farmer has nothing to do ; hu mil t 

 leave all to nature. With the root, however, lie l.as 

 everything to engage his attention that supplies 



the plant with the stamina which enables it to acquire a 

 living and productive form. 



Now, as soils differ in their nature, they are accordingly 

 fit for the growth of OORMpOBding plants, and every 

 plant, as is well known, will not flourish equally in every 

 soil. Clay consists chiefly of silica and alumina; and 

 when it contains about forty per cent, of sand, it allonls 

 a clay-loam. The colour of clay is caused by the j 

 of oxide of iron. If a soil contain from ten to twenty 

 per cent, of lime, it becomes a marl ; and with a 

 proportion, as in the chalky soils of Kent and Sussex, a 

 calcareous, or lime soil is afforded. 



When a soil is too close, inferior crops are pro 

 and some plants, as tho potato, will not grow, or will pro- 

 duce inferior crops. Hence, in travel! 

 ranges of country, we find jj: ity of crops. In 



Kent, Kssex, Suffolk, A-c. , wo find cereal produce pre- 

 vailing, with rotations of turnips and potatoes. In the 

 Midland Counties grass is chiefly cultivated, for grazing 



