384 BULLETIN OF THE BUSSEY INSTITUTION. 
waste may be obtained occasionally at a low price, for the waste is 
good for nothing except to be used as manure. But, from the nature 
of the case, the saltpetre waste is liable to vary greatly in quality ; and, 
since its value depends almost wholly upon the nitric acid and the 
potash that are contained in it, the farmer should be careful to have the 
proportion of these ingredients determined by the analysis of a fair 
sample of the material each and every time that he wishes to purchase 
any of it. When the quantity of waste to be disposed of is as large as 
the lot from which the foregoing sample was drawn, the cost of an analysis 
would be small in comparison with the value of the material, and would 
hardly be felt at all if several farmers were to combine to buy the 
whole of the waste with the view of dividing it and the costs of pro- 
curing it, among them. As an example of the varying character of 
saltpetre waste an analysis reported by Professor Johnson,* of New 
Haven, in 1868, may be cited. Johnson’s sample was found to contain 
9.630, of potash and 2.90% of nitric acid [or nitrogen 1.04%] and 
moisture 11.52%, while its price was $35 per ton. 
It is of interest to note that the proportions of the saline constituents 
in Johnson’s sample were unlike those of the sample analyzed in the 
Bussey laboratory. ‘Thus while Johnson could report as a probable 
arrangement of the bases and acids the statement given below under 
C; the small amount of sulphuric acid in my sample precluded such 
an arrangement, and, suggests the statement (taken from analysis A) 
which is given under D. In a word, Johnson’s sample contained a 
large proportion of sulphates, and my sample contained a large 
amount of chlorides. 
C. D. 
Sulphate of potash . . . . . 11.39% 4.10% 
Sulphate of soda . . . . . . 22.52 — 
Chloride of sodium . . . . . 388.75 about 45.00 
Nitrate of potash... ... ». 7.48 13.62 
Chloride of potassium ....—- ., 28.63 
MOISHITO eos gee nly Wee eee eR 4.94 
It is not unlikely that the saltpetre waste, D, resulted from a process 
of manufacture different from that used in the case of C. Perhaps the 
latter came from the simple recrystallization of East Indian saltpetre ; 
while D may have been formed in some one of the processes by which 
nitrate of soda is converted to nitrate of potash by treatment with a 
* Report Connecticut Board of Agriculture, 1868, p. 217. 
