160 MANURE. 



ammonia be partly or wholly saturated with carbonic acid. 

 Even the excess of that acid does not prevent — it ought 

 rather to increase — the good effects of this compound. 

 Taking, therefore, carbonate of ammonia, which is more 

 readily decomposed than even the muriate, let its effects be 

 compared with that of sulphate, each salt being used in such 

 quantity that the amount of nitrogen shall be equal. 



Jacquemart, carefully conducting this comparative experi- 

 ment, in France, mixed the solution of carbonate of ammo- 

 nia with charcoal or peat, so as to bring it into a dry state, 

 like the sulphate. The salts were sowed with wheat in tbe 

 fall, on the same field, and under circumstances apparently 

 the same. The field had been cleared of bushes, grubbed 

 up, and, after two crops, was limed and marled. Now this 

 liming and marling, though alike in all parts, had a special 

 effect on the sulphate of ammonia ; it imbibed it, and gradu- 

 ally evolved carbonate of ammonia. Hence, in the first 

 year, the sulphate yielded less than portions of the same 

 field un manured. 



But the year following, the experiment was repeated, and 

 the salts, as before used, were again sown with wheat on the 

 same places in which each had been before applied. The 

 sulphate was therefore in a state to act with more efficiency, 

 but still the lime interfered. 



The product was 71 with the sulphate to 70 unmanured. 

 The product, with carbonate and peat, compared with that 

 with sulphate, was as 94 to 71, or as 1 to 0.74. In Kuhl- 

 mann's trials, uninfluenced by lime, it was as 1 to 0.88. Let 

 it be remembered that Kuhlmann used muriate of ammonia, 

 a salt not so easily decomposed as carbonate. To show the 

 influence of lime on sulphate of ammonia, a solution of that 

 salt in the same quantity as before used, was absorbed to 

 dryness by chalk, and sowed with oats. 



