

SALTS OF AMMONIA AND THE NITRATES. 199 



to do with their nearly equal action than the ammonia, soda, or 

 magnesia with which it was combined. 



c That the nitrogen in the nitrate of soda was not in a con- 

 dition to contribute to the growth of the crop. 



But we should be wrong to draw conclusions in regard to 

 any of these points. Suspicions of this kind are only useful 

 when they lead to renewed and more careful experiments. 



2. Again to oats, the second year's crop of this grain on the 

 same field, Mr M'Lintock, near Glasgow, in 1842, applied the 

 following top-dressings on the 13th of May : 



Grain. Straw. Chaff. Hay crop in 



No application gave . 35 bush. 92 stones 304 Ib. 201 stones 



Sulphate of ammonia, 1 cwt. 45j ... 120 ... 260... 195 



Muriate of ammonia, 104 Ib. 50 ... 140 ... 320 ... 204^ ... 



Nitrate of ammonia, 96 ... 57 ... 161 ... 448... 197^ ... 



Nitrate of potash, 90 ... 60^ ... 176 ... 320 ... 171 



Nitrate of soda, 90... 44 ... 128 ... 352 ... 224* ... 



These results suggest conclusions somewhat different from 

 those of Mr Main. Here the nitrate of potash gave the largest 

 crop, though it was applied in smaller quantity than the sal- 

 ammoniac. The nitrate of ammonia came next, and the sulphate 

 of ammonia produced about an equal effect with the nitrate of 

 soda, in the quantities in which they were in this case applied. 

 There is nothing in these results to lead us to suppose that 

 nitrogen, in the form of nitric acid, is not equally efficacious 

 with nitrogen in the form of ammonia. For while the nitrate 

 of potash beat all the salts' of ammonia, that of soda was as 

 efficacious as the sulphate of ammonia, and, alone of all the 

 applications, caused an increase in the after-crop of hay. 



3. On grass cut for hay, at Barochan, on three separate fields 

 in 1844, the following comparative results were obtained : f 



No application gave . 41 J cwt. 22 J cwt. 27^ cwt. 



Muriate of ammonia, 2 cwt. 72 ... 48^ ... 38 ... 



Sulphate of ammonia, 2 cwt. 76 J ... 40 ... 40 ... 



Nitrate of potash, 2 cwt. 89 ... 57 ... 48 ... 



Nitrate of soda, 2 cwt. . 81 J ... 5l ... 66 ... 



* Transactions of the Highland Society, January 1849, p. 449. 

 f Transactions of the Highland Society, July 1847, p. 21 et seq. 



