426 
Agricultural Chemistry. 
That — " It is not clifBcult to refute tlie opinions of another, if 
we ascribe to him assertions which he has never made " ? 
And that — " It never occurred to me to assert that the land of 
Great Britain was deficient in the substances which are found 
toj^cther in the ashes of tlie crops raised on it," &c. ? 
Or, need we further ask — Where is the Oxford version* of the 
" Mineral Theory," — namely, that " it throws upon the air, or 
ujwn the ingredients of tlie manitres which are organic in their 
origin, the task of furnishing nitrogen to the plant " — where is 
there any trace of this version of the " Mineral Theory " in 
the overwhelming amount of Baron Liebig's own definitions of 
his peculiar doctrines which we have been quoting? 
Secondly. We will now show how Baron Liebig's so-called 
" Mineral Theory " has been understood by other writers than 
ourselves, not only in England, but in Germany, France, and 
America. 
Dr. Muspratt, formerly a pupil of Professor Liebig at Giessen, 
now Professor of Chemistry at Liverpool, and a son of the 
gentleman of that name who undei-took the manufacture of 
Baron Liebig's manures in this country, commenting on a lecture 
by Mr. Karkeek, in which he had detailed the results of some 
experiments with Baron Liebig's manures, says : — 
"lb has long since been established that when the inor£i;anic ingredients 
are all present, and in sufficient quantity, the carbon and nitrogen the plants 
can assume f rom the air without the interference of the farmer, if the land be 
in that physical condition whicli is requisite fur the assimilation of the ammonia 
and carbonic acid present in the atmosj^hcre." — Mark Lane Express, March 
1, 1847. 
Mr. Karkeek, in the course of his reply to Dr. Muspratt, thus 
indicates what he understands is the doctrine of which Dr. 
Muspratt was the representative : — 
" Taking, then, these three experiments as they stand, and well knowing 
that the Trewithen meadow had been very highly manured for a long time, 
while the contrary was the case in the other two instances, I consider that I 
was not much out of the way in stating my opinion that the failure of Liebig's 
manure was the consequence of a want of sufficient quantity of azotised and 
(it should have been reported) carbonised matters in the soil ; and whatever 
Dr. Muspratt may think to the contrary, notwithstanding I have such high 
authority to contend with, yet from the practice whicli I have had in observing 
the effects of various kinds of artificial manures during the past five years, I 
am quite satisfied that the inorganic elements are of very little value as a 
manure for i)lants without a corresponding supply of the organic. Indeed I 
am of ojiinion that plants have neither the power of assimilating the inoi'ganic 
elements in the soil, nor the organic substances from the atmosphere in such a 
degree as to enable the farmer to grow twenty tons of swedes to the acre, unless 
they are also supplied with a proper quantity of carbonaceous and azotised 
substances at the same time." — Mark Lane Express, March 22, 1847. 
* See Saturday Review of Nov. 10 and Dec. 1, 1855, ct seq. 
