Elements of Agricultural Chemistry (1815)
Sir Humphrey Davy

Inert peaty matter is a substance of the same kind. It remains for years exposed to water and air without undergoing change; and in this state yields little or no nourishment to plants.

Woody fibre will not ferment unless some substances are mixed with it which act the same part as the mucilage, sugar, and extractive or albuminous matters, with which it is usually associated in herbs and succulent vegetables. Lord Meadowbank has judiciously recommended a mixture of common farm. yard dung for the purpose of bringing peats into fermentation; any putrescible or fermentable substance will answer the end; and the more a substance heats, and the more readily it ferments, the better will it be fitted for the purpose.

Lord Meadowbank states, that one part of dung is sufficient to bring three or four parts of peat into a state in which it is fitted to be applied to land; but of course the quantity must vary according to the nature of the dung and of the peat. In cases in which some living vegetables are mixed with the peat, the fermentation will be more readily effected.

Tanners spent bark, shavings of wood and saw dust, will probably require as much dung to bring them into fermentation as the worst kind of peat.

Woody fibre may be likewise prepared so as to become a manure by the action of lime. This subject I shall discuss in the next Lecture, as it follows naturally another series of facts, relating to the effects of lime in the soil.

It is evident from the analysis of woody fibre by M. M. Gay Lussac and Thenard, (which shews that it consists principally of the elements of water and, carbon, the carbon being in larger quantities than in the other vegetable compounds) that any process which tends to abstract carbonaceous matter from it, must bring it nearer in composition to the soluble principles; and this is done in fermentation by the absorption of oxygene and production of carbonic acid; and a similar effect, it will be shewn, is produced by lime.

Wood-ashes imperfectly formed, that is wood-ashes containing much charcoal, are said to have been used with success as a manure. A part of their effects may be owing to the slow and gradual consumption of the charcoal, which seems capable, under other circumstances than those of actual combustion, of absorbing oxygene so as to become carbonic acid.