200 KUHLMANN'S EXPERIMENTS. 



On these grass fields the nitrates were more successful than 

 the salts of ammonia, and in only one of the cases did the muriate 

 exhibit a more favourable influence than the sulphate of am- 

 monia. 



4. Again on grass, M. Kuhlmann made two comparative 

 series of experiments, the first with sulphate of ammonia, and 

 the nitrates of soda and lime ; the second with muriate of am- 

 monia and the nitrate of soda. These results were as follows, 

 per hectare : 



a The same plots were top-dressed with equal quantities of 

 the salts in 1844 and 1846, being left without top-dressing in 

 1845. 



1844. 1845. 1846. 



Total 

 increase. 



No application gave . . 3820 kilos. 4486 kilos. 3330 kilos. 



Sulphate of ammonia, 250 kilos. 5564 ... 4170 ... 5193 ... 3291 kilos. 



Nitrate of soda, 250 ... 5690 ... 4390 ... 5383 ... 3827 ... 



Nitrate of lime, 250 ... 5397 ... 4420 ... 4023 ... 2204 ... 



b In his second experiment, equal applications of muriate of 

 ammonia and nitrate of soda were made in 1845 and 1846, to 

 the same plots of the same old grass field, with the following 

 results, per hectare : 



1845. 1846. 



Total 

 increase. 



No application gave . . 7744 kilos. 3519 kilos. 



Muriate of ammonia, 200 kilos. 9388 ... 5576 ... 3700 kilos. 



Nitrate of soda, 200 ... 9543 ... 4523 ... 2803 ... 



In the former experiment the increase upon the two years 

 was greater from the application of the nitrate of soda, than 

 from that of the sulphate of ammonia. In the second, though 

 the nitrate produced a large increase, it was surpassed by that 

 which was caused by the addition of the muriate of ammonia. 



The experiments brought together in this section present the 

 only data we as yet possess from which we can hope to extract 

 an answer to the question, Whether or not the sensible effect of 

 the salts of ammonia and of the nitrates is in direct proportion 

 to the quantity of nitrogen they respectively contain ? I shall 

 examine them in reference to this point in the following section. 



