94 Experiment Station Report. 



Nova Scotia Plaster (Oypsum.) 



(Collected of D. A. Horton, Northampton, Mass.) 



Per cent. 

 Moisture, at 100° C, . . . . . . lo.79 



Calcium oxide, 

 Magnesium oxide, 

 Sulphuric acid, 

 Insoluble matter, 

 Carbonic acid, 



34.29 



0.36 



47.14 



1.42 



Not determined. 



This gypsum contained a few per cent, of calcium and magnesium 

 cai'bonates, which not unfrequently are associated with it. 



" Orchilla " Guano. 



(Collected of D. A. Horton, Northampton, Mass.) 



Per cent. 



Moisture, at 100° C, 11.05 



Magnesium oxide, 4.13 



Calcium oxide, 38.24 



Phosphoric acid, 21.69 



Insoluble matter, 0.17 



The " Orchilla" guano belongs to a class of natural phos- 

 phates which are noted for their deficiency in organic and 

 nitrogenous matter, as well as for their large percentage of 

 carbonate of lime. The above described sample contained 

 47.39 per cent, of bone phosphate, and 22.39 per cent, of 

 carbonate of lime. The presence of so large a percentage of 

 the latter compound renders this material, from an econo- 

 mical standpoint, unsuitable for the manufacturers of super- 

 phosphate of lime. The natural pnlverent condition of the 

 ommercial article has favored its introduction into agricul- 

 tural practice. Very satisfactory results are reported from 

 its application in case of moist pastures and meadows, and 

 of turfy soils. Upon a dry soil and in a dry season its 

 action can be but slow. The safest way to secure an eco- 

 nomical return seems to be a direct introduction in the daily 

 product of stable manure, on account of the beneficial action 

 of the fermenting animal excretions on the disintegration of 

 the guano, and thus an increased solubility of its bone phos- 

 phate. Four cents per pound for phosphoric acid might be 

 considered a safe investment. At that rate of valuation the 

 above article would be worth $18 per ton of two thousand 

 pounds. 



