ARTIFICIAL MANURE. 211 



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; alkali and porous substances 

 act like spongy platina, they induce a catalytic power, 

 and the consequence is, that the elements of the air, oxygen 

 and nitrogen, unite and form nitric acid, this combines with 

 tiie alkali, and consequently nitrates are produced. The 

 other well-established fact, in relation to the action of am- 

 monia 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 producing soluble 

 geine. The formation of nitrates may be quite, and ordina- 

 rily is prevented. It is the alkaline action which is sought. 



264. By the addition of alkali to peat, it is put into the 

 state which ammonia gives to dung. The question then 

 arises, How much alkali is to be added to swamp muck or 

 peat, to convert that into cow-dung 1 Recurring to the doc- 

 trine of chemical proportions, whose value to the farmer is 

 thus made evident, it will be remembered that the equiva- 

 lent of pure potash and soda, that is, that portion of one 

 which can take the place of the other, is as 2 to 3 ; that is, 

 2 parts of pure soda are equal to 3 of pure potash. If either 

 of these is compared with ammonia, it will be found that one 

 part of pure ammonia is nearly equal to two of soda. When 

 these substances are met with in commerce, it is in the state 

 of salts, as carbonate of ammonia of the shops, white ash, 

 or soda ash, or potash and pearlash. The equivalent of these 

 is deduced from determining the pure alkali of each, and 

 adding the equivalent of carbonic acid. It is found that, 



59 lbs. of pure carbonate of ammonia are equal to 



54 lbs. " soda, or to 



70 lbs. " potash. 



