RECENT RURAL PUBLICATIONS. 399 



example, a clover-crop, growing ou grouud which has received a heavy 

 dressing of Avood-ashes and lime, will very early in the season produce 

 such a mass of foliage as to screen the soil from the light most effectu- 

 ally, and operate as a very perfect mulch to the earth ; thus inducing 

 the prime condition for the formation of nitrates. After all, it may be 

 that Professor Ville means no more than that in this indirect manner 

 l^lauts receive nitrogen from the air. If so, we assent. 



But to return : this doctrine of predominating substances has much to 

 recommend it in the practical application of manures. Out of this 

 grows the practice of using special manures for certain crops. The law 

 governing the application of special manures, derived from the experi- 

 ments of a series of years, is laid down in this work with sufficient clear- 

 ness to enable any farmer of ordinary intelligence to apply it in practice. 



The indiscriminate use of fertihzing agents has been a source of great 

 waste both of labor and money. The first step toward a rational use of 

 manures is to determine what is already in the soil in a sufficient quantity, 

 and what is wanting. On this subject our author very justly remarks, 

 (page 43 :) " It has often been thought that chemical analysis would fur- 

 nish the i)roper indications, but we are now obliged to give up this hope. 

 The four substances to which the soil owes its fertility are there found 

 in various states — soluble and active, insoluble and inactive. As chem- 

 istry has not yet succeeded in making these necessary distinctions, its 

 testimony is not a sufficient guide for agricultural practice." He, there- 

 fore, recommends analysis by experimental culture of small lots, each 

 with a different fertilizer ; and, by noting the result, a correct conclu- 

 sion may be reached as to what elements of fertility are deficient in the 

 soil. 



While this treatise furnishes the American farmer a clear statement 

 of general principles, and submits valuable formulae for both special 

 and complete manures, yet it will require a careful discrimination to 

 apply these to the demands of American agriculture. For example, the 

 rotation of crops recommended, (page 73,) and the manures to be used 

 each year, however appropriate they may be in European farming, are 

 almost worthless to us. Any rotation Avhich gives prominence to beets, 

 colza, vetches, and horse-beans, and almost entirely ignores corn, 

 (maize,) is of but little value anywhere in the United States. A farmer, 

 however, who understands the ]ninciples upon which the system of rota- 

 tion is constructed can very readily make such changes and substitu- 

 tions as will adapt it to his own peculiar circumstances. 



The values at which the different ingredients composing the manures 

 recommended are estimated are certainly below the lowest prices in our 

 market. For example, superphosphate of lime, at IG francs per 100 

 kilograms, is $1.38 per lOU pounds, or $37.60 ])er ton, (3,000 pounds,) 

 which is but little more than 'half its market- value in gold. So, nitrate 

 of potassa is put at $5.35 per 100 pounds ; nitrate of soda at $3.03, and 

 sulphate of ammonia at $3.88 per 100 pounds. 



In estimating the cost of chemical manures, our farmers must take into 

 the account this disparity, and make their calculations accordingly. 

 But even at this low estimate the cost of fertilizers in the rotations of 

 crops recommended by Professor Yille will be apt to startle American 

 farmers. In his several, rotations for grain-crops, the annual expense 

 for manures ranges from 300 francs per hectare, down to 165 ; which, 

 in good Saxon English, is from $15.38 to $13.69 per acre. If we add to 

 this 33 per cent, for the difference in price of the articles used, the 

 amount will probably, at the present price of farm -products, deter most 

 farmers from following this leading. It will be remembered, however, 



