CHAPTER XI. 



Experiments with the nitrates of potash, soda, lime, and magnesia. Composi- 

 tion of the nitrates of potash, soda, lime, and magnesia their properties and 

 their functions in the soil and in the plant. Sensible effects produced by the 

 application of the nitrates of potash and soda. Results of past experiments 

 with the nitrates of potash, soda, and lime. Results of experiments with 

 nitrate of soda applied in different proportions to the same crop. Suggestions 

 for new experiments with the nitrates of potash, soda, lime, and magnesia. 



1. Composition of the nitrates of potash, soda, lime, and 

 magnesia their properties and their functions in the soil and 

 in the plant. 



1. COMPOSITION of the nitrates of potash, soda, lime, and 

 magnesia. 



a The nitrate of potash ) . , - f potash, . . 46 6 

 or saltpetre / c< )f | nitric acid, . 53*4 



100 



b The nitrate of soda } . , - ( soda, ... 36'7 



-,. > consists of < ... ., _ ft 



or cubic petre I nitric acid, . 63*3 



100 



Both salts, however, as they occur in commerce, are mixed 

 with a variable proportion of impurity. Saltpetre contains 

 about 5 per cent of chloride of potassium or of common salt, and 

 nitrate of soda from 5 to 12, or even 20 per cent of common 

 salt. The proportion of common salt in the latter may be 

 roughly estimated by throwing a little of it on a red-hot plate, 

 when, if it contain common salt, it will. decrepitate or crackle; 

 if not, it will quietly melt. 



c The nitrates of lime and magnesia, when perfectly dry, 

 consist respectively of 



