84 



NEW ENGLAND FARMER. 



March 



catechism 



— OF — 



AGRICULTURAL CHEMISTRY AND GEOLOGY. 



by james f. w. johnston, m. a. 



[continued.] 



Q. Woody fibre, starch, gum, and sugar consist 

 of carbon and water only ; of what does water it- 

 self consist ? 



A. Water consists of oxygen and hydrogen. 



Q. Hovi much of each of these elements is con- 

 tained in icaier ? 



A. Every 9 lbs. of water contain about 8 lbs. 

 of oxygen, and 1 lb. of hydrogen. 



Q. Is it not a very extraordinary thing that 

 liquid water, which pids out all fire, should consist 

 of two gases, one of which (hydrogen) bums read- 

 ily, while in the other (oxygen) bodies burn with 

 great brilliancy ? 



A. Yes, it is very wonderful ; but there are 

 many other 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 con- 

 sist of the same elements as starch and woody 

 fibre. 



Q,. Of what elements, then, do these substances 

 consist ? 



A. They all consist of carbon, hydrogen and 

 oxygen. 



Q. Of what does gluten consist ? 



A. Gluten consists of all the four elements — 

 carbon, hydrogen, oxygen and nitrogen — united 

 together. 



Q. Does the plant derive from the air all the el-' 

 ements of which gluten consists? 



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 Grow. 



Q. What does the soil consist of '? 



A. The soil consists of an organic or combus- 

 tible, and of an inorganic or incombustible part. 



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 the fire or over a lamp. The soil will 

 first turn black, showing the presence of carbona- 

 ceous matter, and will afterwards assume a grey- 

 brown or reddish color as this black organic mat- 

 ter burns away. 



Q. Whence is the organic part of the soil de- 

 rived ? 



A. It is derived from the roots and stems of 

 decayed plants, and from the dung and remains 

 of animals and insects of*various kinds. 



Q. Does this organic part form a large propor- 

 tion of the soil ? 



A. Of peaty soils it fo v ms sometimes three- 

 fourths of the whole weight; but of rich and fer- 

 tile 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 docs not 

 contain a considerable proportion of organic mat- 

 ter? 



A. Not in our climate. A rich soil generally 

 contains at least one-twentieth of its weight (J 

 ppr font ^ of r*i"ffapif> rnMfp»\ 



Q. Does the organic matter increase or dimin- 

 ish in the soil, according to the way in which it is 

 cultivated ? 



A. Yes, it diminishes when the land is fre- 

 quently plowed and cropped, or badly manured ; 

 and it increases when the land is planted, when 

 it is laid down to permanent pasture, or when 

 large doses of farm-yard manure or of peat com- 

 post are given to it. 



Q. What purpose does this organic matter serve 

 in the soil ? 



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 quantiy they draw from the soil varies 

 with the kind of plant, with the kind of soil, and 

 with the season ; but it is always considerable, 

 and is necessary to the healthy growth of the 

 plant. 



Q. If plants ahcays draw this organic matter 

 from the soil, will the soil not become gradually 

 poorer and less productive') 



A. It will, if badly managed and constantly 

 cropped. 



Q. Then how can you keep up the supply" 



A. By plowing in green crops, — by growing 

 clovers and other plants which leave long roots in 

 the soils, — by restoring all the hay and straw to 

 the land in the form of manure, — or by laying 

 down to pasture. 



Q. Whence is the inorganic part of the soil de- 

 rived ? 



A. The inorganic part of the soil is derived 

 from the crumbling of the solid rocks. 



Q. Of what do these rocks principally consist 1 ? 



A. They consist of more or less hardened 

 sandstones, limestones and clays. 



Q. Do soils consist principally of the same sub- 

 stances ? 



A. Yes, soils consist principally of sand, clay 

 and lime. 



Q. How would you name a soil which contained 

 one of these substances in large quantity 1 ) 



A. If it contained very much sand, I would 

 cf.ll it a sandy soil ; if much clay, a more or less 

 stiff clay soil ; if much lime, a calcareous soil. 



Q. Bid if the soil contained two or more of 

 them in large proportions how tvonld yon name iff 



A. A mixture of sand and clay with a little 

 lime, I would call a loam ; if much lime was pres- 

 ent, I would call it a calcareous loam ; and if it 

 were a clay wiih much lime, I would call it a cal- 

 careous clay. 



A Useful Hint to Horse-Keepers. — A gen- 

 tleman who has tried the plan successfully for 

 five years, communicates the annexed method of 

 preventing horses from chafing under the c liar. 

 He says he gets a piece of leather, and has what 

 he terms a false collar made, which is simply a 

 piece of leather cut in such a shape as to lie 

 snugly between the shoulders of the horse and the 

 collar. This feeds off all the friction, as the col- 

 lar slips and moves on the leather, and not on the 

 shoulders of the horse. Chafing is caused by the 

 friction, hence you see the thing is entirely plausi- 

 ble. Some put pads or sheepskins under the col- 

 lar, but these do as much harm as good, for they 

 augment the heat. A single piece of leather, like 



