l72 MANURES. 



will soon become so large that it will hold the water 

 of any ordinary rain, and withstand the evaporation 

 of any drouth, if not very severe. If it inclines to 

 dry up, it is well to throw over it a few quarts of 

 plaster. Plaster is very little soluble. Five hundred 

 lbs. of water dissolve but one lb. of plaster. It 

 cannot, therefore, be lost by putting it on moist 

 manure, as some other salts might be. Indeed, it 

 should be sprinkled over all manures frequently, 

 but especially if they incline, either in consequence 

 of dry weather, or of too rapid fermentation, to be- 

 come dry. 



824. Some have supposed that the outer pen for 

 swine should be under cover. I think not. Kemem- 

 ber that rain does not hurt manure, unless it run 

 through it, carrying off its soluble salts. Every drop of 

 rain brings down ammonia and other fertilizing mat- 

 ters from the air. The falling rain washes the air of its 

 impurities. After a shower, we say, " How sweet the 

 air is." It is sweet, because it is clean. Hence, in the 

 neighborhood of cities and large villages, and every- 

 where, to a limited extent, rain falls, impregnated with 

 enriching materials. If it fall on a quantity of ma- 

 nure, whicb has sufficient depth to hold it, till evapo- 

 ration takes place, it leaves these materials in the ma- 

 nure. Hence, the more rain the better, provided it 

 go off by evaporation, and not by filtration. The eva- 

 poration should not go on to perfect dryness, for then 

 the ammonia, the carbonic acid, and other gases, are 

 Inclined to escape, and the manure is approaching that 

 state in which it may be said to be " burnt." 



