290 EXPERIMENTS ON POTATOES WITH DIFFERENT MANURES. 



It will thus be seen that the soil was not remarkably rich, but 

 contained a fair proportion of ammonia, potash, and phosphoric 

 acid, and also a moderate supply of plant food in a soluble con- 

 dition, such as is most necessary for the growth of crops. It 

 will be unnecessary to give a detailed analysis of the manures 

 employed, for although all the substances present were estimated, 

 yet, by reason of the very small quantities of many of them 

 present, they could have no influence on the results ; therefore 

 the amount of the principal constituents only will be found in 



the following tables 



Phosphates. 



The sample of kainit was found to contain 27*21 per cent, of 

 sulphate of potash ( = 14-7 K2O) ; the sample of " potashes" pre- 

 pared from crude tartar contained 5 9 "77 per cent, of potash 

 (52-05 per cent, being present combined in the form of carbonate 

 of potash) ; the sulphate of ammonia, a fine white sample, con- 

 tained 96*44 per cent, of pure sulphate. 



