Davy — Observations on Nitrification. 247 



and of albuminoid ammonia, as determined by "Wanklyn's process, 

 varied very considerably with the time the sample of water had been 

 kept ; but neither of those gentlemen has offered (in the letter re- 

 ferred to) any explanation of the fact, further than that Professor 

 P. Muir throws out the suggestion, in the case of the increase by keep- 

 ing of the albuminoid ammonia, that possibly it might have been 

 owing to the germs which have escaped decomposition by the per- 

 manganate, undergoing a gradual decomposition in the water, and that 

 ammonia is one of the products of this process. Be this as it may, I 

 have satisfied myself that the loss of free ammonia is often due to the 

 formation of nitrites or nitrates, which are very rapidly formed under 

 different circumstances. And as regards albuminoid ammonia, the 

 very slight increase which I observed in my experiment was, I 

 thought, very easily accounted for by my having in the second deter- 

 mination carried on the process of distillation somewhat further than 

 in the first trial, and in this way the amount might be very naturally 

 increased. 



Finally, my observations that nitrification is greatly promoted by 

 warmth might, I conceive, admit of some practical application in the 

 manufacture of the nitrate of potash in the artificial nitre beds, 

 especially in those of cold countries ; and I am not aware that heat 

 has hitherto been anywhere artificially applied to hasten or promote 

 that important manufacture. 



