442 
Af/ricultural Chemistry. 
To this we answer in the negative. And, let us see, how Baron 
Liebig seeks to show, that our experiments contradict the equiva- 
lent assertions — " that the mineral constituents of wheat cannot by 
themselves increase the fertility of land," and " that the produce 
in giain and straw is rather proportional to the supply of am- 
monia." 
We have before explained (see Diagram I.), that plot 10 
of our experimental wheat-field was manured in 1844 with a 
mixture of silicate of potass and superphosphate of lime, and in 
every subsequent year one portion of it (10a) received a very 
liberal amount of ammonia salts only : the result being a very 
considerable increase of produce compared with the unmanured 
plot. This increase, according to Baron Liebig, is due to 
the — 
" constituents of the soil, plus 560 lbs. of superphosi^ate of lime, i)kis 220 
lbs. of soluble silicate of potass, plus 1960 lbs. of ammoiiiacal salts ;" 
And he goes on to say — 
" it follows that the increase of produce was by no means the effect of the 
ammonia alone, as Mr. Lawes will have it, but that the active mineral con- 
stituents of the soil just meutioued have had their full share in producing 
this effect. 
" What, then, are the circumstances in which theory leads us to anticipate 
such an increase of produce ? 
" The answer will be found in my work, p. 134." 
We give the sentence as it really does occur at page 134 of the 
fourth edition of Baron Liebig's work, the portions between 
brackets, thus [ ], being omitted by Baron Liebig in his quo- 
tation {Principles, p. 109) : — 
" The cereals require the alkalies and silicates liberated by the lime, and 
rendered fit for assimilation by plants. If there be present decaying matter 
yielding to the plants carbonic acid, their development may be favoured by 
this means ; but this is not necessary. For if we furnish to the soil ammonia, 
and to the cereals the phosphates essential to their growth, [i/i the event of 
their being deficient,] we furnish all the conditions necessary for a rich crop, 
[as the atmosphere forms an incxhaustihle mafjmine of curhouic acid,j " 
The object of this sentence in Baron Liebig's work, was 
simply to explain that the beneficial action of burnt lime upon 
soils depended upon its liberating in the soil, the " alkalies and 
silicates " which the cereals require, and that, as the amount of 
humus must thereby be lessened, it was obvious that, in the 
event of other constituents not being deficient, the plants were 
enabled to rely upon the atmosphere as an inexhaustible magazine 
of carbonic acid. Whether or not Baron Liebig's 'Theory,' as 
amply developed in entire chapters of the same work, as well as 
in other writings, is properly represented by this individual and 
mutilated sentence, the reader will judge for himself, from the 
evidence we have adduced as to what that theory really was. 
