Agricultural Chemistry. 
429 
stand Baron Liebig's doctrine ; we quote from a few of these, 
some of whom have also given their opinion as to the truth of 
that doctrine. 
Professor F. G. Schulze, of Jena, thus defines Baron Liebig's 
theory (we quote from p. 204 of the ' Patent Office Report ' for 
1848 ; Washington, 1849) :— 
" The stable manure which agriculturists furnish, essentially aids vegetable 
life, only by what it contains of alkalies, lime, silica, and other mineral ele- 
ments, not by what it contains of cavbon, hydrogen, oxygen, and nitrogen, 
for these substances plants can obtain from the air, as an inexhaustible source. 
As now in stable manures, the mineral elements bear the proportion of some 
two to seven per cent, of the whole mass, so the agriculturist, who yearly 
brings on his fields 100,000 cwt. of stable manure, canies out 93,000 to 
98,000 cwt. in vain. It would be far more simple and less costly to give 
the plants only mineral manures, and to leave them to acquire their organic 
means of nutriment from the air." 
" In the burning of plants, the organic, not the inorganic portions, are dissi- 
pated. Hence the agriculturist can burn bis crops, namely, his straw, and 
yet continue his fields in the strength hitherto possessed, if he only carries on 
the ashes acquired by such burning. But if circumstances do not permit him 
to manure the plants with such ashes, yet can the same object be attained, if 
by the aid of chemistry he will examine into the ash constituents of his 
harvest, and carry the mineral substances corresponding to his analysis upon 
his field." 
Dr. Weissenborn, of Weimar, in an article entitled ' Observa- 
tions on Liebig's Patent Manure ; with a Comparative View of 
the Theories of Thaer and Liebig,' thus expresses himself in 
regard to Baron Liebig's principles : — 
" The great rule of the new system of manuring is the following : — Let the 
fields not be manured with stable-dung, nor with any sort of dung whatever 
that contains organic (vegetable or animal) substances, along with its inorganic 
(mineral) principles. This mineral manure the farmer has to procure, either 
by incinerating all the vegetable substances that he has reaped, and which he 
cannot profitably sell or consume on his farm, especially by burning the straw ; 
or by applying to a chemist, with a view of having both the soil to be ma- 
nured and the ashes of the plant to be cultivated duly analysed, and of getting 
prepared conformably to the result of such analyses an artificial manure 
(mineral manure, manure of ashes), containing the very mineral food that the 
plant wants, and that is not already contained in the ground." 
" The advantages of the new system of manuring are represented to be the 
following : — 
" 1. The farmer saves almost the whole of the expenditure for transporting 
maniu'c to the fields, as the weight of the mineral manure he wants is only 
2'6 per cent, of that of the stable-dung hitherto used. 
" 2. On fields manured after the new system, the vegetation cannot mate- 
rially suffer from want of rain. 
" 3. The straw may be sold ; and most of the live stock, that scarcely ever 
yields a net revenue, may be dispensed with. 
" 4. The rotation of crops is rendered unnecessary, and any sort of crop may 
be raised on the .same field without intermission. 
" This theory of Professor Liebig is refuted by the following principal facts 
— &c., &c. — Farmer's Magazine, vol. xv., 1847, p. 3C9, 
VOL. XVI. 2 F 
