410 Philosophy of Manures. 



ammonia to have the offensive smell of perspiration, as stated. 

 But he found only -^^%q of a grain in the pound of rain water, 

 rather more than one twelfth ; whereas Dr. Liebig made it one 

 fourth of a grain. Perhaps some difference may arise from rain 

 falling more frequently where the analysis of the reviewer was 

 made. This would yield only Tlilb. of ammonia to the acre. 

 He found, also, he says, his analysis would give 64-1^ lb. of 

 common salt : it must surely have been from rain collected near 

 the sea. The reviewer states it as his opinion, that animals fed 

 on substances destitute comparatively of nitrogen, as oil-cake, 

 which contains little nitrogen and an excess of hydrogen, will 

 produce fat, and not beef or muscle, the fibrin, albumen, and 

 osmazome of which contain much nitrogen. Substances con- 

 taining nitrogen will also yield most muscular tissue, he says, 

 especially if steady and continued exertion be used. That sub- 

 stances yielding nitrogen should be productive of substances 

 containing nitrogen is certainly fair inductive reasoning ; yet, 

 as I said before, I have seen" persons fed on potatoes, con- 

 taining little nitrogen, who were very muscular : they had, how- 

 ever, plenty of exercise in the open air. Some authors are of 

 opinion that nitrogen is inhaled. From Dr. Liebig's statement 

 of its being found, in an uncombined state, around the living 

 organs, it appears also to act as a stimulant. The reviewer next 

 notices Dr. Liebig's opinion, "that sulphate of lime is valuable 

 as fixing the volatile salts of ammonia;" but says this is value- 

 less, as the particles of soil are capable of retaining \ per cent 

 of ammonia, which would yield nitrogen for fifty years to the 

 heaviest crops of wheat : there can be no need, he says, for fixing 

 it. The sulphate of lime acts only, he says, as forming a con- 

 stituent of the plant. Independently, he says, of the nitrogen 

 contained in the soil, the 30 tons of manure will yield 268j lb., 

 or only If lb. less than the whole four crops of turnips, barley, 

 hay, and oats require. 



On the subject of alkalies, the statement of the definite quan- 

 tities required for each plant, he says, is new and valuable. He 

 is of opinion, however, that every soil contains these in sufficient 

 quantity. As to sandy soil not producing wheat for want of 

 alkalies, he says an acre of wheat will not consume above 50 lb. 

 of potash ; while an acre of turnips, which agrees with sandy 

 soil, will consume 92j lb. The whole four-shift rotation of 

 wheat, barley, hay, and oats consumes 1,091 lb. of saline matter; 

 while the 30 tons of manure given with the turnips, he says, 

 yields 7,324- lb. of saline matter, or 1,556 lb. per annum more 

 than needed. The reviewer proposes to resume the subject 

 ao-ain ; and, when men of such talent and opportunities for 

 investigation thus devote themselves to such subjects, we are 

 certainly warranted in expecting much valuable insight to be 



