M. YILLE'S EXPERIMENTS. 13 



" These facts, proved in pure sand by means of fertilizers chemically 

 prepared, were next repeated in the soil of a field on the imperial farm 

 at Vincennes, at the expense of the emperor. * * * 



" During the past four years, curious visitors, drawn to the farm by 

 the report of M. Ville's experiments, have been shown a series of square 

 plots, manured and sown in conformity with rules laid down to test their 

 efficacy. Upon some of these plots the seed has never been varied ; the 

 same soil has been planted four times in succession with wheat, colza, 

 pease and beet-root ; giving them, at the commencement, a supply of the 

 normal manure, and adding annually what M. Ville terms the dominant 

 ingredient — that is to say, the special manure of the series. Upon the 

 other plots the seed alternated during the quarternary period at the 

 expense of the normal manure, by changing the dominant according to 

 the nature of each plant introduced into the rotation ; and under these 

 conditions the crops have reached to results of irrefutable eloquence. 



" By adding, according to M. Ville's system, nitrogenous matter, phos- 

 phate of lime and potassa — thac is to say, a normal or complete manure 

 to calcined seed, the seed — wheat being equal to 1 — the crop is i-epre- 

 sented by 23. 



" Upon withdrawing the nitrogenous matter from this mixture of the 

 four elements, the crop fell to 8.83. 



" Upon withdrawing the potassa, and retaining all the others, the crop 

 only attained to the figure 6.57. 



" When the phosphate of lime was omitted, the crop was reduced to 

 0.77 ; vegetation ceased, and the plant died. 



" Lastly, upon abstracting the lime, then the crop, the maximum of 

 which was represented by 23, was only 21.62. 



" From the above facts we draw these conclusions : that if the four 

 elements of a perfect manure, above named, act only in the capacity of 

 regulators of cultivation, the maximurfi effect they can produce implies 

 the presence of all four. In other words, the function of each element 

 depends upon the presence of the other three. When a single one is 

 suppressed, the mixture at once loses three-fourths of its value. 



" It is to be remarked, that the suppression of the nitrogenous matter, 

 which causes the yield of wheat to fall from 23 to 8.33, exercises only a 

 very moderate influence upon the crop, when the plant under cultivation 

 is leguminous. But it will be quite otherwise if, in such cases, we 

 remove the potassa. 



" If we extend the experiment to other crops, and successively suppress 

 from the mixture one of the four ageirts of production, we arrive at the 

 knowledge of the element Avhich is most essential to each particular 

 crop, and also which is most active in comparison with the other two. 

 For wheat, and the cereals generally, the element of fertility par excel' 



