PRESENT THEORY AND PRACTICE OF MINERAL MANURES. 437 
A document published by the Central Society of Agriculture of Bel- 
gium describes a piece of land of a sugar plantation in the Commune 
of Visé (Province of Liege) which had become so beet-sick that neither 
manure nor rotations could produce any root fit for manufacture. This 
piece was divided into two portions, on one of which Viile’s chemical beet 
manure was used, and on the other a strong supply of good farm manure 
wasapplied. During the early growth the difference was so apparent 
as to astonish the workmen. At the harvest 39,520 kilograms of uniform 
excellent roots were taken off the Ville portion, while from the barn- 
manured piece only 18,200 kilograms of inferior, stunted rocts were 
obtained. It would be easy to multiply the recital of results made 
in different parts of France, all showing the real value of these mineral 
manures. 
To obtain the utmost value of each mineral in the manure, Ville 
modifies his formulas. Thus, in a four-year shift, comprising the rota- 
tion of beets, wheat, clover, and wheat, he prefers to employ each year 
the following manures: 
First year, beet root: Acid phosphate of lime 400 kilograms; nitrate of potassa, 200 
kilograms ; nitrate of soda, 400 kilograms; sulphate of lime, 300 kilograms. 
Second year, wheat: Sulphate of ammonia, 300 kilograms. 
Third year, clover: Acid phosphate of lime, 400 kilograms; nitrate of potassa, 200 
kilograms; sulphate of lime, 400 kilograms. 
Fourth year, wheat: Sulphate of ammonia, 300 kilograms. 
The whole cost of these manures in France is 770 frances, equal to a 
yearly outlay of 192 francs 50 centimes. We watch with intense inter- 
est the working out of this agricultural problem in France, as it involves 
two very important considerations, namely: Ist. The use of chemical sub- 
stances as manures, given in exact weights and in variety suitable for 
rotations; 2d. Of the sole dependence upon these to the neglect, either 
partial or total, of the use of barn manure, and of a sapply of vegetable 
matter in the soil. 
Two questions force themselves upon the consideration of those who 
look on this Trench experiment, viz: 1st. Can land be treated indefi- 
nitely to raise crops by the use of chemical manures alone? 2d. Is it 
advantageous, in a financial or economic point of view, to employ 
chemical manures? The first question is one which no argument can 
decide ; it is one to be settled by repeated experiments. If solved in the 
affirmative, it is a very important step in advance in practical agricul- 
ture. The second question can be decided much sooner. There are, 
already, warning voices raised from different localities in France that, 
with the present prices of chemical substances, these mineral manures 
cannot compete with those of the farm-yard. In that country ammoni- 
acal salts cost 2 francs the kilogram; insoluble organic matter, 1 frane; 
insoluble phosphate, 25 centimes; soluble phosphate, 75 centimes; 
potassa, 60 centimes; pure lime, 14 centime; and Peruvian guano 33 
centimes the kilogram. Whenever chemical manures exceed the pre- 
ceding rates to any extent, they will cease to be remuneratively 
employed. A little time will settle this question, also. Meanwhile, the 
well-known fact of soil exhaustion is apparent, and we should take to 
heart the following language of Liebig: 
The visible, gradual deterioration of the arable soils of most civilized countries can- 
not but command the serious attention of all men who take an interest in the public 
welfare. It is of the utmost importance that we do not deceive ourselves respecting 
the danger indicated by these signs as threatening the future of populations. An ini- 
pending evil is not evaded by denying its existence, or shutting our eyes to the signs of 
its approach. It is our duty to examine and appreciate the signs. If the source of the 
evil is once detected, the first step is thereby taken to remove it forever. 
