132 Observations on Liebig's " Organic Chemistry J" 



spread out on the ground, when, bemg more volatile than the 

 other salts of ammonia, it is apt to escape into the air, unless 

 washed into the soil, where it may be united to other acids if pre- 

 sent, or taken up by the roots, but he thinks it most likely to be 

 volatilised. The other salts of ammonia are taken up by the roots. 

 When the carbonate of ammonia is lost, he says, the loss is 

 equal to nearly one half of the urine employed ; and he proposes 

 various methods to fix it : as strewing a field with gypsum, and 

 then with the urine, which will convert the carbonate into the 

 sulphate of ammonia. It may be done more easily, he says, by 

 mixing the urine with gypsum, chloride of calcium, sulphuric 

 acid, muriatic acid (spirit of salt), or superphosphate of lime, 

 all cheap substances, which would convert the volatile carbonate 

 of ammonia into more fixed salts. If a basin of muriatic acid 

 is put in contact with the fumes of ammonia from a necessary, 

 it is converted, he says, into crystals of muriate of ammonia 

 (sal ammoniac). The ammonia which escapes in stables is 

 converted into nitric acid, when in contact with the lime of 

 the mortar, which dissolves the lime, and forms soluble nitrates. 

 If the floors of our stables and necessaries were strewed with 

 gypsum, they would lose their offensive smell, by the volatile 

 carbonate of ammonia, which gives the smell, being converted 

 into sulphate of ammonia, a valuable manure. The uric acid con- 

 tains, next to urea, most nitrogen ; it is soluble in water, and can 

 thus be absorbed by the roots, and its nitrogen formed into ox- 

 alate, hydrocyanate, or carbonate, of ammonia. In respect to 

 the quantity of nitrogen, he says that 100 parts of the urine of 

 a healthy man are equal to 1,300 parts of the fresh dung of a 

 horse, and 600 parts of a cow's dung. 



The powerful effects of urine as a manure are well known 

 in Flanders; and are considered invaluable by the Chinese, the 

 oldest agricultural people. Their laws attach so much value to 

 human excrements as to forbid their being thrown away, and 

 reservoirs are placed in every house to collect them with the 

 greatest care; very little value is there attached to the excre- 

 ment of animals. The Chinese were before us in dyeing and 

 painting, and in manufactories of porcelain and silk; but by the 

 aid of chemistry, he says, we have now been enabled to surpass 

 them. How infinitely inferior still is the agriculture of Europe 

 to that of China ! They are the most admirable gardeners 

 and trainers of plants in the world ; and know how to prepare 

 and apply the best-adapted manures. With us, he says, thick 

 books are written, and we do not know yet what manure 

 is ; no experiments being instituted. Calculating the urine of 

 a man at Ijlb. daily, and the fasces at j lb., and that both 

 yield 3 per cent of nitrogen, about 16^ lb. of nitrogen would be 

 furnished annually, which would be sufficient for 800 lb. of 



