326 BOARD OF AGRICULTURE. 



Sample No. I. was collected from a Boston dealer, and 

 No. II. from a farmer in Mansfield, Massachusetts ; both 

 proved, according to the above-stated analyses, to be of a very 

 good kind. A good average quality of Chili saltpetre con- 

 tains 95 per cent, of pure nitrate of soda, and sold during 

 the past year for from 4| to 4 cents per pound. The price 

 of nitrogen in the form of Chili saltpetre has been about 25 

 cents per pound during the past year. The reputation of the 

 Chili saltpetre as an efficient source of nitrogen for top-dress- 

 ing, or for late spring application, in case of soils rich in 

 phosphates, is steadily gaining ground. It acts, as a general 

 rule, best in dry seasons, which is partly ascribable to the fact 

 that it increases the hydroscopic qualities of the soil. 



Dried Blood. 



Moisture, 15.89 



Nitrogen, 7.80 



(Equal to 9.5 per cent, of ammonia.) 



The sample tested had apparently suffered from an excessive 

 heat during the process of drying. A carefully dried pure 

 blood contains from 14 to 15 per cent, of nitrogen. One 

 hundred parts of good blood, varying from 1.045 to 1.075 

 specific gravity, furnish about 20 parts of dry mass. 



Dry blood is a superior source of nitrogen for fertilizing 

 purposes, and therefore is frequently used as a concentrated 

 stock for *the manufacture of our common nitrogenous or 

 ammoniated superphosphates. 



There are two grades of dry blood in our markets, contain- 

 ing respectively from 10 to 12 per cent, and 6.5 to 8.5 per 

 cent, of nitrogen. 



The differences in moisture of various articles may also be 

 sufficiently large to affect seriously their relative commercial 

 value. The price of dried blood may thus differ per ton from 

 $20 to $40 without being necessarily too high or too low in 

 either case. 



Consumers do well to buy always with a special reference to 

 the percentage of nitrogen of the article offered for sale ; the 

 latter sells at from 21 to 22 cents per pound. 



The manufacture of dry blood for fertilizing purposes is 



