PROCEEDINGS OF THE CHEMICAL DEPARTMENT. 1 63 



difference between the lowest and the highest only amounts to 

 about 10 per cent. The best effect, therefore, is produced by 

 the ready formed ammonia, and this result is precisely what 

 might have been anticipated from the character of the season. 

 It appears, from the table of the rainfall given in a preced- 

 ing page, that after the manures were applied there was an 

 unusual drought, continuing for several weeks ; and it is clear 

 that, from the extreme dryness of the soil, those decompositions 

 by which the nitrogenous compounds yield ammonia either 

 could not take place at all, or were at least greatly retarded, 

 so that, during the whole of that period, their nitrogen was 

 comparatively inaccessible, while the sulphate of ammonia of 

 course yielded it to the plants as they required it. It was in 

 fact at this time that the difference was most apparent, those 

 plots which got the ready formed ammonia having at once taken 

 a start in advance, and the advantage they gained at that time 

 was maintained during the rest of the season. In connexion 

 with this point it is curious also to notice the very trifling 

 difference between the plots manured with uric acid and Peru- 

 vian guano. As the latter contains nearly half its nitrogen as 

 ready formed ammonia, it would have been anticipated that its 

 produce should have stood midway between the former and 

 sulphate of ammonia, whereas it is scarcely increased. This is 

 one of those anomalous results which we must expect sometimes 

 to encounter in the pursuit of agricultural experiments. 



EXPERIMENTS ON HAY, 



The field on which this experiment was made had carried a 

 crop of oats in 1864, and was sown out with one bushel each of 

 Italian and Perennial Eyegrass seeds, and 2 lbs. each of cow 

 grass, alsike, and red clovers. The crop having made con- 

 siderable progress before the manures were ready, it was con- 

 sidered advisable to have it cut before they were applied. This 

 was done on the 26th May, and the manures were sown on the 

 following day on plots 1-1 12th of an acre, and surrounded with 

 wires as in the oat experiments. The immediate effect of the 

 applications was precisely the same as that which took place in 

 the oat crop, the nitrogenous manures at once producing an 

 effect, those containing sulphate of ammonia very distinctly 

 taking precedence of the others, and this continued till the end 

 of July, when the hay was in flower, and there is every pro- 

 bability, from its appearance, that, had the crop been cut at that 

 time, the results would have been a complete counterpart of 

 those given by the oats. Mr Thomson, however, thought it 

 better to leave the crop standing, and to watch its progress from 

 week to week in order to see what changes occurred. This 

 was continued till the 11th September, by which time it was 



