i879-J 
The Science of Agriculture. 
357 
poses, or for growing forage plants, and reserving the other 
for cereal crops, which was equal to asserting that in order 
to grow cereals there must be meadow land, cattle, and 
manure. Instead, however, of growing meat in order to 
have corn, he must grow corn for profit’s sake in the first 
place, and afterwards for straw, cattle-feeding, and manure. 
The objedt of the farmer, then, should be not to produce 
manure, but to manure his land more abundantly than for- 
merly. No matter what may be the material he employs, 
whether it be farmyard or chemical manures, used either 
together or separately, he must somehow or other give back 
to the soil a larger amount of fertilising material than that 
lost by the growth of the crops. In the cultivation of the 
soil increase of produdtion depends less on the worker and 
on the quality of the tools which he employs than upon 
the quantity of fertilising materials which he has at his 
disposal. According to M. Ville the only way to do this is 
to employ chemical manures, and to prove his assertion, to 
show that with chemical manures large crops may be quickly 
obtained from the most barren lands, he refers among others 
to an experiment carried out by M. Ponsard, President of 
the Agricultural Committee of Omey in Champagne, on a 
piece of waste land in one of the most, barren districts of a 
proverbially barren portion of that province. M. Ponsard 
manured one half of the ground with about 32 tons of farm- 
yard manure per acre, and the other with about half a ton 
of chemical manure per acre. With the farm manure he 
obtained 14 bushels of wheat, whereas with chemical manure 
the land yielded about 30 bushels, there being a loss of £19 
in the former case and a gain of £ij in the latter. 
Similar experiments have been made with beet-root, pota- 
toes, sugar-cane, &c., and in each case the results have been 
in favour of the chemical manure. In fa (ft, by varying the 
quantity of the ingredients entering into the composition of 
chemical manure, so as to suit the requirements of each 
class of plants, the work of vegetation may be regulated 
almost like a machine, the usefulness of which is in propor- 
tion to the fuel it consumes. The first point is to discover 
the degree of richness of the natural soil, and then to ascer- 
tain the dominant constituent of each plant. Plants are 
divided into three categories — first, those in which nitro- 
genous matter is the dominant constituent, such as cereals, 
hemp, colza, beet-root, and general garden stuff. The 
second group, in which calcic phosphate preponderates, 
comprises maize, sugar-cane, Jerusalem artichokes, turnips, 
and sorghum. The third group includes leguminous plants, 
