Agricultural chemistry / [George Cox].

  • Cox, George
Date:
1844
Catalogue details

Licence: Public Domain Mark

Credit: Agricultural chemistry / [George Cox]. Source: Wellcome Collection.

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    indeed it varies according to circumstances, but any one may satisfy himself that there it does exist. The small quantity of air usually employed for an analysis, contains so inappreciable a quantity, that it is impos- sible to prove its presence by the usual tests; but by collecting rain water as it hills, especially after long continued dry weather, we possess ourselves of all that which was diffused previously over a large area, because ammonia is so soluble in water, that it is sure to be taken up by it. Liebig’s experiments in the Giessen laboratory have placed the presence of am- monia in rain water beyond doubt. He distilled some hundreds of pounds weight of fresh fallen rain water in a copper still, and on evaporating the first two or three pounds, after adding a very little muriatic acid, a distinct chrystallization of sal ammoniac was obtained. The chrystals had always a brown or yellow colour. It is likewise always present in snow water : chrystals of sal ammoniac were obtained by evaporating in a vessel containing muriatic acid, several pounds weight of snow gathered from the ground in March, when the snow had a depth of ten inches. Ammonia was set free from these chrystals by the addition of hydrate of lime, and the inferior layers of snow contained a de- cidedly greater quantity than those upon the surface. “ The employment of animal manure in the cultivation of grain, and the vegetables which serve for fodder for cattle, is the most convincing proof that the nitrogen of vegetables is derived from ammonia. The quantity of gluten in wheat, rye, and barley, is very variable, and these kinds of grain, even when ripe, also contain this compound of nitrogen in very different proportions. Proust found French wheat to contain 12.5 per cent, of gluten; Vogel found that i)
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