ARTIFICIAL MANURE. 183 



tic potash, exerts its usual action ; it may be added, 

 that possibly in the process of vegetation, when the 

 decomposing power of the living plant is exerted on 

 peat, and the silicates, caustic potash is produced, 

 and ammonia evolved. Considering peat as a source 

 of nitrogen only, it is evident that the action of al- 

 kali is of the highest practical importance. 



263. In this part of the subject of manure, prob- 

 abilities and possibilities are no longer admissable. 

 There are two facts, well established by experience, 

 relating to the action of ammonia in dung. First, it 

 has been shown (166) that dung produces nitrates. 

 Porous substances and alkali, possess the power of 

 forming nitrates ; these substances, alkali and porous 

 bodies, act like spongy platina, they induce a cata- 

 lytic power, and the consequence is, that the ele- 

 ments of the air, oxygen and nitrogen unite, and 

 form nitric acid, this combines with the alkali, and 

 consequently nitrates are produced. The other well 

 established fact, in relation to the action of ammonia 

 in dung, is the power of dissolving and converting 

 geine, which has been explained in Chap. IV. The 

 most valuable of these two properties is that of pro- 

 ducing soluble geine. The formation of nitrates 

 may be quite prevented, and ordinarily is prevented. 

 It is the alkaline action which is sought. 



