402 MASSACHUSETTS AGRICULTURE. 



CHEMISTRY OF AGRICULTURE. 



From an Address before the Housatonic Society. 



BY GEO. E. "WARING, JR. 



Let US suppose that we wish to examine the composition of 

 vegetable matter. We will take as a type of this, a cord of 

 wood, which, if burned, entirely disappears, with the exception 

 of a small quantity of ashes. Now in this simple combustion 

 we have the clue to the analysis of plants, for we thus make 

 the grand division between the two classes of matter of which 

 plants are composed, one of which remains on the hearth as 

 ashes, and which was derived from the soil, and another which 

 escapes into the atmosphere from which it was originally ob- 

 tained by the plant. This is apparently lost ; but in nature's 

 economy loss is unknown. To-day's decay is to-morrow's in- 

 crease, and the volatile portions of the wood sent into the air by 

 combustion, float there subject to the demands of the meanest 

 weed. This air-born part of our crops is composed of four 

 different kinds of matter, — Carbon, Oxygen, Hydrogen and 

 Nitrogen, — by the various combinations of which all combustible 

 matter, having a vegetable origin, is formed. Wood, sugar, 

 wax, starch, gum, resin, etc., all being composed of the first 

 three of these, combined in varied proportions, and a class of 

 highly nutritious matter, of which the gluten of wheat is a 

 type, being formed of the whole four. To examine minutely 

 each of these substances, and to investigate their various 

 changes in the plant, would be highly interesting, but is 

 impossible in our short interview. That we may see how they 

 behave in their many ramifications, we will follow carbon in its 

 various changes. 



If we take carbon (or charcoal), and burn it, it unites with 

 the oxygen of the air and becomes carbonic acid, which is the 



