162 



PROCEEDINGS OF THE CHEMICAL DEPARTMENT. 



In examining this table the point which most immediately 

 attracts attention is the entire inefficacy of the Peruvian 

 guano ash. When employed alone the produce is exactly the 

 same as that from the nothing plots, and when mixed with uric 

 acid and glue the result is also identical with that obtained, 

 when those substances are used without it. Along with sulphate 

 of ammonia, however, it does produce a slight increase in the 

 produce, but it is so small as scarcely to merit notice. This 

 result is of special interest when we call to mind the opinion of 

 Liebig, that the farmers need only apply in his manures these 

 substances which are found in the ash of his crops — an opinion 

 not generally entertained by chemists, and which has been 

 recently to some extent modified by the author himself. The 

 ash of Peruvian guano contains all the constituents of the ash of 

 plants, not. certainly, in the proportions required for a grain 

 crop, and some of them in very small quantity ; but still it 

 would be expected that they should have produced some effect, 

 while none was observed. 



\Vherever nitrogenous manures are applied, however, the 

 effect is extremely marked, the produce being greatly increased, 

 and that nearly to the same extent in all cases. They cannot, 

 however, be described as quite equal, for glue stands lowest, 

 then comes uric acid ; Peruvian guano slightly exceeds it, and 

 sulphate of ammonia gives a still higher increase, but the 



