LOSS OF NITIJOOKN DlIMNir !• I'Kl )I \( ; i.>r.:» 



at Rotliamsteil in IS7A with n'uj^s, ihc aiiiinals l.rin^ ciiirmrd in 

 a frame resting upon a sloping' zinc hottoni. Tlicy were \vatclic(| 

 (lay and night diu-ing the experinu'Ulal period, .md ih.- vnidinu'- 

 were collected as soon as passed, and analvsiMl ai ic^nlar 

 intervals for dry matter, ash, and nitrot^cn. The results wen-, 

 however, not satisfactory ; there was a considci-al.Ii' iK.ition <.r 

 the nitrogen of the food unaccounted for in eitlicr tljc increase 

 of weight or in the excrements. The results seenjed to show 

 that the loss was probably due to the difhcuhies of j»roj)er 

 collection and analysis of the excreta, so that the experiment 

 was repeated with greater precautions in 1862. This time the 

 losses of nitrogen were much reduced, and when allow aiiet' wa> 

 made for the many unavoidable sources of error, tlie results 

 supported the idea that the whole of the nitrogen of the food 

 not stored up as increase passed over into tlu^ maiun-e. ( )tliei- 

 experiments were made with sheep; but again it was impossible 

 to avoid some mechanical losses, and to eliminate the une(M-tainty 

 due to lack of exact knowdedge of the composition of the 

 animal at the beginning and close of the experiment. 



Later experiments on the Continent have indeed set the 

 point at rest, and shown that there is ncj decomposition of 

 nitrogenous matter of the food into nitrogen gas during the 

 vital processes, but that the whole of the digested nitrogen 

 which is not utilised for increase, milk, etc., is voided in the 

 urine. 



The practical question which greatly occupied the attention 

 of Lawes and Gill)ert was that of tlie manure value (.f the 

 many purchased cattle foods commonly used in ihi> country, 

 and particularly the compensation t(j be paid to an ouiLroini: 

 tenant for their consumption in the latter years of his tenancy, 

 liefore he could be supposed to have ol)tained a return from 

 them in the shape of the crop. Lawes and (Jill)ert fiierefon- 

 prepared a table showing the composition of most of the cattle 

 foods commonly in use, and calculated wiiat proportion of the 

 nitrogen, phosphoric acid, and pc^tash present would under 

 normal conditions be retained bv fattening stock consunn'n.u' tin- 



