206 OF MANURE. 



Nitrate of soda has lately engaged much attention, 

 and is supposed to exert its favorable action upon 

 vegetation by yielding nitrogen to those constitu- 

 ents of plants which contain it. The experiments 

 which have hitherto been instituted with this ma- 

 nure do not warrant us in concluding with positive 

 certainty that it is the nitrogen alone to which it 

 owes its efficacy, but they certainly render this a 

 plausible explanation of its virtues. Thus Mr. 

 Pusey, the late able president of the Royal Agri- 

 cultural Society, has shown, that the same effects 

 are produced by putrefied urine, soot, gas-liquor, 

 and nitrate of soda.* Now the three former act by 

 virtue of the ammonia which enters into their com- 

 position. The usual effects produced by these and 

 nitrate of soda are to increase the intensity of the 

 green coloring matter, to augment the quantity of 

 straw, but to produce a light grain. Mr. Hyettf 

 has communicated the results of an analysis of two 

 samples of w^heat grown under similar circumstances, 

 one of which had been treated with nitre, the other 

 not. The former contained 23*25 per cent, of gluten, 

 and 1.375 of albumen ; the latter only 19 per cent. 

 of gluten, and 0.62 of albumen. Here the azotized 

 matters appear to have considerably increased in 

 quantity. There is nothing opposed to the sup- 

 position that nitric acid may be decomposed by 

 plants, and its nitrogen assimilated. We find that 

 vegetables possess the power of decomposing car- 

 bonic acid, and of appropriating its carbon for their 

 own use. Now this acid is infinitely more difficult 

 to decompose than nitric acid. But there are other 

 circumstances which oppose the adoption of the view 

 that nitrate of soda acts by virtue of the nitrogen 

 which enters into its composition. Were this the 

 case, the action should be more uniform than it has 

 hitherto been found to be. On some soils the salt 

 does not possess the smallest influence; whilst on 



* Journal of the Roval Agricultural Society, Vol. II. p. 123. 

 t Ibid., Vol. II. p. 143. 



