PROCEEDINGS OF THE CHEMICAL DEPARTMENT. 165 



The results obtained in this case are somewhat different from 

 those observed in the oats. Guano Ash, which there proved 

 useless, has here produced a perceptible effect, having raised the 

 produce from 42 (the average of the nothing plots) to 52| cwt. 

 This appears to be due to the irregular growth of the clover ; 

 for towards the end of August it was observed that the propor- 

 tion of clover on the Peruvian guano plots, and on the sulphate 

 of ammonia, glue, and uric acid plots, to which guano ash had 

 been added, was decidedly less than the normal amount ; on 

 those plots where the nitrogenous manures were used without 

 the guano ash the clover had almost entirely disappeared, while 

 it was increased to a very marked extent where guano ash alone 

 was applied. It is difficult to explain how this should be, but 

 there can be no doubt that the effect of the ash must be attri- 

 buted to this ; for, as far as the eye could judge, it had no effect 

 whatever upon the ryegrass. With this exception, the results 

 are similar to those of the oats, the ready formed ammonia tak- 

 ing the highest place, though the difference between it and the 

 others is but small. Sulphate of ammonia and guano ash stands 

 highest, and is followed by Peruvian guano, glue and ash, and 

 uric acid and ash, in the order now stated, and the yield of the 

 first exceeds that of the second by about 2 per cent, the second* 

 surpasses the third by nearly f per cent., and there is about the 

 same difference between the third and the fourth. These varia- 

 tions are very trifling, and undoubtedly find their explanation in 

 the dryness of the season, and the imperfect decomposition of 

 the nitrogenous compounds, occasioned by want of moisture, 

 and it seems probable that they would not have been observed 

 in an ordinary year, but that all would have produced the same 

 effect. 



The conclusions to be drawn from these experiments are very 

 obvious. They completely bear out those of the last season, and 

 prove incontestably that uric acid acts as a manure, and is 

 scarcely if at all inferior to the ready formed ammonia. In last 

 year's experiments the effect produced on turnips by sulphate of 

 ammonia was somewhat superior to that of uric acid, and I 

 attributed this to the late period at which the turnips were sown, 

 and the dryness of the season, which was quite exceptional. 

 Unfortunately the same meteorological peculiarities have mani- 

 fested themselves this year, and the effect on the action of the 

 manures has been of a similar character. The difference between 

 them, however, is far from considerable ; and it is worthy of 

 notice that the effect of the dry season is not confined to the 

 uric acid, but shows itself quite as distinctly with gelatine, re- 

 garding the value of which as a manure no doubt can exist. 



The entire absence of manurial effect from the application of 

 the mineral constituents of Peruvian guano, as applied to the 



