238 



On Agricultural Chemistry. > 



more philosophical relation to each other all over the world than 

 at present. The system of cultivation in England may be con- 

 sidered as tending to such a result more nearly than that of most 

 other countries, and if the principles which it involves were 

 properly understood and carried out, we might become inde- 

 pendent of foreign supplies^, even if our population were much 

 greater than it is now. I have before stated that the ammonia in 

 a manure is employed by grain-plants to determine carbonaceous 

 products : the same principle is apparent in the economy of 

 animals. Dr. R. D. Thomson, in his experiments, found that 

 the cow which received the largest amount of nitrogen in its 

 food produced the greatest weight of butter ; and the general 

 experience of agriculturists ascribes the most fattening properties 

 to those substances which contain the greatest proportion of 

 nitrogen. Although ammoniacal manures favour the elaboration 

 of carbonaceous matters in grain, we might expect to find a dif- 

 ferent result in examining the seeds of the leguminous plants. 

 The peculiarity of these plants is to produce a seed containing 

 a highly nitrogenous element, called legumen. In our own 

 experiments we find grain in the driest state contains one and 

 two, but rarely three per cent, of nitrogen. We find in the dry 

 substance of clover-seed as much as 7 per cent., and in beans and 

 peas 5 per cent. The proportion of nitrogen in the seeds of 

 these plants would, therefore, probably increase, within certain 

 limits, under the influence of ammoniacal supply. The following 

 results obtained by Dr. Gilbert seem to favour this view : — 





Per centage of 



Nitrogen 

 in Dry Matter. 





Exp. 1. 



Exp. 2. 





4- 77 



5- 11 



4- 78 



5- 09 



In the seeds of cruciferous plants, turnips and rape for ex- 

 ample, a non-nitrogenous product, oil, seems to abound, and we 

 might expect that ammoniacal manures would tend to enhance its 

 production in such plants, in like manner as that of starch is 

 increased in the seeds of the gramineous family. Turnip-seed is 

 - not, however, cultivated in England with a view to its oily pro- 

 ducts, and I have only investigated the effect of ammoniacal 

 supply upon the leaf and bulb of the plant. 



In reference to the circumstances under which the formation 

 of the special product of plants seem to be increased, a few re- 

 marks upon the cultivation of sugar-cane may not be out of place. 



