35 



can save, are just the most expensive of those which he pur- 

 chases, so that it becomes a most important point for him to 

 consider the ways and means by which this saving of those ele- 

 ments can be effected. This is the art of composting. 



Nothing in this world is easy ; and all things to be well done, 

 must be done with accurate knowledge and careful judgment. 

 The art of composting is no exception to this, and in order to 

 compost intelligently, the planter must know something about 

 the chemistry of organic and inorganic substances, and the laws 

 by which he must work. As, owing to the great differentiation 

 of knowledge, we cannot expect all planters to acquire this 

 knowledge, it becomes the duty of the chemist to interrogate 

 nature, study her laws, and then impart to him the result. 



All plants or portions of therrf when they die, and are left 

 exposed to air and moisture, undergo decomposition, that is the 

 highly complex arrangement of their atoms is broken up, and 

 more simple forms are assumed. 



This decomposition may take place in two ways: First, by 

 eremacausis, or slow decay, which is an oxidizing process ; 

 second, by putrefaction or fermentation, which is a reducing 

 process the only difference between putrefaction and fermenta- 

 tion being that in the former offensive odors are emitted, and in 

 the latter, none. 



Eremacausis requires an excess of free oxygen, and therefore, 

 takes place in bodies freely exposed to the air, while putrefac- 

 tion, though it seems to require oxygen to commence, only 

 proceeds in the absence of oxygen, or at least when that 

 element is present only in small quantity. Thus, if we take a 

 substance undergoing slow decay, and exclude the atmosphere, 



Eutrefaction sets in ; and vice versa, if we take a body in putre- 

 ictive decomposition, and expose it freely to the air, the rapid 

 decomposition ceases, and slow oxidation ensues. 



The final results of these two methods of decomposition 

 differ considerably, and are of especial importance, in this 

 inquiry. 



In eremacausis, or slow decay, the carbon and oxygen unite 

 to form carbonic acid; the hydrogen and oxygen to form water, 

 while nearly all the nitrogen escapes as free gas, a small por- 

 tion only forming nitric acid; while in putrefaction a portion 

 only of the carbon unites to form carbonic acid, some of it 

 escaping in combination with hydrogen as marsh gas, some as 

 carbonic oxide, while a large portion remains as humus. The 

 hydrogen also, though mostly combining as water, yet also 

 forms marsh gas, and remains as one of the elements of humus; 

 while all the nitrogen unites with hydrogen to form ammonia. 



Thus it appears that the object of the planter should be to 

 arrange his materials so as to produce putrefaction, and at the 

 same time to retain those valuable products which may escape 

 as gas or in solution in drainage water. 



