VALUE OF FRESH AND MADE MANURES. 263 



composed before leading them out to the field is attended with a 

 considerable loss of fertilizing principles, and that it is therefore 

 advantageous to use them in the state in which they come from the 

 stable. To remove all doubts which might yet be entertained upon 

 the effects of unfermented manures, M. Gazzeri showed that wheat 

 could be successfully grown in land which had received an extraor- 

 dinary dose of pigeon's dung, which is regarded as one of the most 

 active of all manures ; and horse droppings, taken at the moment 

 they were passed, mixed with earth, in the proportion of one-fourth 

 of the whole bulk, had no injurious effect on the growth of the 

 cereals. To ascertain the amount of loss which fresh manures suf- 

 fered from fermentation, M. Gazzeri placed certain quantities, as- 

 certained by weight, to putrefy under flivorable circumstances ; and 

 the decomposition completed, be weighed them again. In this way, 

 he ascertained that horse-dung, in the course of four n.onths, lost 

 more than the half of the dry matter which it contained before its 

 putrefaction. Davy, indeed, had already shown that there is a loss 

 of volatile principles, during the decomposition of fresh manures, 

 that must be useful to vegetation. Davy's experiment consisted in 

 introducing manure into a retort, the extremity of which communi- 

 cated with the soil under turf, and he found that in the course of a 

 few days the grass which was thus exposed to the emanations from 

 the retort, grew with particular luxuriance. Although it appears 

 certain, then, that in conducting the preparation of manure in the 

 heap with prudence, the volatile and ammoniacal principles which 

 appear in the course of the putrefaction may be retained, it is never- 

 theless unquestionable that the employment of manure directly and 

 without previous fermentation, would most effectually prevent the 

 loss of matters that must be valuable. Thaer, Schwertz, Mr. Coke, 

 and others, have consequently admitted the advantages of the latter 

 procedure. In agreeing with them completely, which I do, it still 

 remains certain that on the greater number of farms, dung-heaps 

 must be formed as matter of necessity. Manure is only available at 

 certain determinate seasons of the year ; it cannot be carried out 

 and spread as it is produced. In Alsace it is carried out to the fields 

 on which it is to be spread whenever circumstances will permit, and 

 without regard to its more or less advanced state of decomposition. 

 The circumstances which lead to its being kept in the pit for two or 

 three months, also lead to the manure being half or more than half 

 matured before it is led out ; and this, after all, is perhaps the best 

 state in which it can be put into the ground. It is then easily incor- 

 porated with the soil, and its fertilizing principles are already in that 

 condition which enables them to act, within a limited time, with 

 greater energy than they would do were the manure employed quite 

 fresh. This is the condition in which our manures almost always 

 are at Bechelbroim wlien we carry them out : it rarely happens that 

 they have been three months on the stance before their removal. 

 Speediness of action is a point which is not without importance. 

 Fresh dung will always act more slowly than that which has reach- 

 ed a (pertain point of decomposition, and the advantage which mostl}/ 



