PROCEEDINGS OF THE CHEMICAL DEPARTMENT. 159 



determined by analysis, the first point required was to calculate 

 the quantity of guano which must be used in order to supply to 

 the soil nitrogen equal to 50 lbs. of ammonia. It amounted in 

 this case to 338 lbs., and contained 115 lbs. of ash. Mixtures 

 of guano ash, with uric acid, gelatine, and sulphate of ammonia, 

 in such proportions as to yield in all cases the same amount of 

 nitrogen as the Peruvian guano, were then made, so that there 

 were thus obtained so many manures, identical in all respects, 

 except in the form in which nitrogen existed in them. These 

 mixtures were further contrasted with guano ash, uric acid, 

 sulphate of ammonia, and gelatine applied alone. 



The plots extended in every case to 1-1 12th of an acre, 

 a quantity which presents great convenience in practice, and 

 has proved well suited to the purpose. They were carefully 

 measured off, and pins being fixed in the corners, galvanized 

 iron wires were stretched between them, so as distinctly to mark 

 off and separate each. Numerous nothing plots were inter- 

 spersed between those to which the manures were applied. 



EXPERIMENTS ON OATS. 



These experiments were made by applying the manures as 

 a top-dressing, and this was done on the 25th of May, when 

 the land was in excellent condition. The rainfall during the 

 month of May amounted to rather more than 3 inches, but the 

 month of June was remarkably dry — only 1-100 inch having 

 fallen during the first four weeks, as may be more particularly 

 seen from the subjoined table of the rainfall during the con- 

 tinuance of the experiments : — 



Table I. Showing the amount of rain which fell on the experi- 

 mental field during the months of June, July, August, and 

 September, 1865 : — 



Month. Week ending . Inches. 



June 7 . . 0-29 



14 .. 0-01 



21 .. 000 



, 28 .. .. 0-80 



July, 5 049 



12 .. .. 0-75 



19 . . . . 0-92 



26 .. .. 006 



August, . . . . 2 . . 0"37 



,, 9 .. .. 0-06 



„ 16 1-61 



„ 23 .. .. 0-55 



„ 30 ... .. 2-28 



September, . . . . 6 . . . . 1.02 



..13 .. .. 0.35 



Total, . . 9.56 



In the course of a few clays, all the plots to which manures 

 containing nitrogen had been applied showed a very conspicuous 



