214: ARTIP^ICIAL M.iKURE. 



used with such signal success by O. M. Whipple, Esq., of 

 Lowell. On the principles which have been developed, 

 when saltpetre is used, the whole alkali is let loose by the 

 action of the growing plant. The experience of Mr. Whipple 

 is a guide to the quantity of alkali which may be safely 

 used. He has used fronn 50 to 150 lbs. saltpetre per acre. 

 The real alkali in saltpetre may be called ^ of its weight ; or 

 the real alkali used has been from 25 to 75 lbs. = 36| lbs. 

 and 109| lbs. pure carbonate, or, in round numbers, an aver- 

 age of commercial 1st and 2d quality, of 49 to 147 lbs. per 

 acre, giving an average of 99 lbs., nearly, which is nearly 1 

 per cent, of the weight of a cord of green peat, which agrees 

 with the estimate (268). If, then, this is mixed with the 

 usual proportion of geine, which the dung used contains, 

 equally good effects per acre ought to be produced. 



270. There are other practical facts which may help to a 

 solution of the question. How much alkali is to be added to 

 a cord of peat 1 According to the experience of the late 

 Mr. Phinney, of Lexington, an authority which may not be 

 questioi^ed, a cord of green dung converts twice its bulk of 

 peat into a manure, of equal value to itself — that is, a cord 

 of clear stable-dung, composted with two of peat, forms a 

 manure of equal value to three cords of green dung. In- 

 deed, the permanent effects of this compost, according to Mr. 

 Phinney, exceed those of stable-dung. Equal bulks are here 

 about equal weights. On these facts, 2 lbs. of ammonia in 

 100 of cow-dung, should convert 200 lbs. of fresh dug peat 

 into good cow-dung. The equivalents of these, as has been 

 shown (265), are 2 lbs. of soda ash, or 3 lbs. of potash. 

 Allowing the gaseous ammonia to be here retained by the 

 peat, and consequently all effective, it is divided equally 

 among the 300 lbs. of dung and peat, in proportion of lOf 

 oz. of soda ash, or 1 lb. of potash to 100 lbs. of fresh peat. 



