80 THE CATTLE OF GREAT BRITAIN. 



viz., sulphate of magnesia and lime, and carbonate of lime, to 

 whicli are added bone flour — i.e., phosphate of lime — used 

 to reduce the strength and add a valuable fertiliser. The 

 gaseous products of decomposition are sulphuretted and phos- 

 phuretted hydrogen, either free or in conjunction with ammonia, 

 though, as we shall see by-and-by, the latter is, when the 

 decomposition occurs in connection with vegetable matter, pro- 

 vided for in another way. Sulphurous acid causes decomposition, 

 being in itself also destroyed, the resultant products being 

 sulphur, phosphorus, and water. Sulphurous acid further acts 

 as an anti-putrescent by its affinity for oxygen, absorbing that 

 gas and preventing other bodies combining with it. Carbolic 

 acid is the most powerful anti-putrescent known, and at once 

 arrests fermentation in a remarkable manner. Its regular and 

 frequent exhibition, not only on the floors and walls of the cow- 

 houses, but by impregnating the air by wet cloths, &c., did 

 more to keep off cattle plague contagion than any other pre- 

 ventive measure, and there is strong evidence to show it was 

 effective. The magnesia is introduced in order to form a 

 double compound of phosphorus and ammonia, highly valuable 

 as a fertiliser. 



The great point necessary for the due preservation of fold- 

 yard manure is its compression ; hence the advantage of small 

 yards, into which the sweepings of the stable, cow byres, &c., 

 are carefully spread. Now, for strong land, manure cannot be 

 in too fresh a state, and therefore it may be removed at once 

 from the yard and spread upon the land ; but on the light land, 

 and in order that the manure may acquire a uniform condition, 

 it is necessary that it first undergo a fermentative process in the 

 heap ; and during this stage loss may be incurred. A certain 

 proportion of runnings, more or less, will break away from the 

 heap ; hence it is well to make the heap upon some good 

 absorbent. The best we know of is red clay ashes, broken to 

 powder ; six inches of such a bottom is very valuable. The 

 heap must be carefully built, the sides kept as plump as 

 possible, and the top after a few days may be lightly covered 

 with soil. Some moisture is necessary to start the process, but 

 our soil prevents the washing effect of heavy rains. In a few 

 days fermentation commences, and proceeds rapidly. Some- 



