E. J. Russell and E. H. Richards 



521 



Looking over the results it will be observed that in no case does 

 the nitrogen present as complex compounds become reduced to less 

 than 50 % of the original nitrogen, and even before it falls so low the 

 rate of loss becomes very small : further, the total loss of nitrogen is 

 rarely more than 40 %,— the remaining 60 % apparently being more 

 resistant than the rest. Cow manure, bullock manure, and the mixed 

 manure at Woking, all show these relationships. 



Ar3rAffT, /Irr^/f An£R A/r^/t 



d /1o/Ym5. ^ /io/^r//j 9m/Yr//5. 



Fig. 6. Changes in nitrogen compounds in farmyard manure (cow manure) 

 stored in loose heaps in the open for varying periods. 



On the reactions taking place in the heap. 

 I. The study of similar cases. 



The changes observed in the nitrogen compounds are : 



1. Loss of ammonia, 



2. Almost always a loss of total nitrogen, 



3. Almost always a loss of complex nitrogen compounds. 



