Agricultural Chemistry. 
461 
iiwmiroil with bones and sulplmric 
acid, and nearly 10 tons more than its 
average produce, or viore than double 
of this last, which was 8J tons." 
of the laud manured with bones and 
sulphuric acid, and only 1 ton \(icwt. 
more than its average produce, which 
was 8:J tons. But, gyimim without 
rape-cake yave 7 tons t) cwt. less than 
the highest by superphosphate of lime 
in the same year; and 2 tons 11 art. 
less than the average produce of the 
latter I 
Baron Liebig's numerical comment on this " still more incom- 
prehensible " result is therefore simply reversed. But let us now 
see how far his comparison was legitimate, even supposing his 
numbers had not been erroneous. The real fact was, then, that 
gypsum used alone, though even after apatite (phosphate of lime) 
in great excess in the previous year, gave only 5 tons 14 cwt. of 
produce. Tliis, as the result of purely mineral manure, was 
that which, in fairness, should have been compared with the 
" 12 " or ratlier 13 tons 2f cwt. yielded by the phosphate of 
lime and sulphuric acid in the same season. Again, 7 tons 
10 cwt. was the produce of 10 cwt. of rape-cahe, u-ken used alone ; 
and when to this latter amount Is added, that portion of the 5 tons 
14 cwt. by gypsum alone, which may be supposed not to be due 
to the previous dressing of finely powdered apatite, there is cer- 
tainly nothing anomalous in the fact, that the gypsum and rape- 
cake together, gave 10 tons 1 cwt. of turnips. 
It is, then, after such comparisons as those which we have 
pointed out, and on an incorrect statement as to our conclusions, 
that Baron Llebig says of our results, " In what incomprehen- 
sible contradiction do they stand to the opinions of Mr. Lawes !" 
And he adds — 
" It Is out of the question, after the facts just related, to assume that the 
excess of phosphoric acid was necessary, and Avas the cause of the increase. 
Is it then the sulphuric acid, the lime, or both together (gypsum), or is it 
the organic matter in the stable manure and in the rape-cake ?"—Frinciphs, 
p. 129. 
To this we answer — that, icherc the superphosphate of lime ivas 
used, " It is out of the question after the facts just related," to 
doubt, that the action of " the excess of phosphoric acid," or of 
the phosphate of lime, " was the cause of the increase ", in that 
particidar case ! — or, that where the farm-yard manure or rape- 
cake was used, "the organic matter thus supplied," together with 
the mineral constituents they contained, played an Important part 
in providing the actual substance of the Increased crop. 
What, then, Is the result of our examination of Baron Llelug's 
criticism on our experiments and conclusions regarding the growth 
of turnips? It is seen — that his statement of our general conclu- 
sion is incori-ect ; that his allegation as to the amount of phosphate 
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