444 [Assembly 



Nitric acid is found in many plants, combined with soda, lime, 

 or magnesia, particularly in the tobacco and sun flower. It 

 exerts an influence upon grain and grass crops, and a«3ds much 

 fertility to soil. Salpetre is formed by nitric acid in combination 

 with potash. In the districts Tirhoot, Chaprah, and others in 

 India, they obtain three crops, annually, by irrigating their^fields 

 with water impregnated with salpetre. Nitric acid, although it 

 does not appear to form a constituent part of any solid rocks, 

 still is found in almost all soils, particularly in hot regions, such 

 as Africa, South America and India. In parts of these countries 

 it prevails in such large quantities as to be detrimental to plants, 

 forming a crust upon the soil. This generally occurs when rain 

 seldom falls. During summers of severe and frequently recur- 

 ring thunder storms, nitric acid is abundant. This accounts, in 

 part, for the fruitful seasons we always have, when thunder storms 

 are frequent. 



The decay of vegetation forms large quantities of this acid. The 

 mammoth cave in Kentucky yields a surprising quantity of the 

 nitrate of lime. During our war with England, fifty or sixty men 

 were there kept constantly collecting it. It is for this substance 

 that the Chinese take the plaster from their walls for manure, 

 and I cannot but think that it is equal in value to that indispen- 

 sable ammonia, for all the purposes of agriculture. It enters into 

 the circulation of the roots, ascends to the highest leaf, and be- 

 comes decomposed by the sun's rays precisely as carbonic acid 

 does. Jas. F, W. Johnston mentions in one of his invaluable lec- 

 ture on agricultural chemistry, that it is uncertain whether this 

 acid is capable of being decomposed in the roots and. stems of 

 plants where it is excluded from the light. 



' All plants are known to consist of two parts, the first organic, 

 which may readily be burned in the air ; the second inorganic, 

 which remains in the shape of ashes. The first is composed of 

 hydrogen, nitrogen, oxygen and carbon, of which I have spoken ; 

 and the second of chlorine, that contains a large percentage of com- 

 mon salt, and influences the growth of plants where salt is requi- 

 site. Iodine is supposed to hasten germination in plants, but, 

 like chlorine, if used in quantities will prove poisonous. 



