EF. W. Hilgard—Soil Analyses and their Utility. 439 
As regards the analysis itself, I premise that I have always 
found even the most ‘chemically pure” reagents so y 
necessary to reject, as arule, even the purest, after keeping it 
for a few weeks in a glass bottle. The same is true, an 
uniform strength, and precipitating all riche muah precipitates 
Vv ‘ 
As regards Dr. Peter’s failure to determine the amounts of 
soluble silex, nitric acid, ammonia, chlorine, and the degree of 
oxidation of the iron, I agree that the former is desirable, not 
becomes manifest ; as might, indeed, have been foreseen. — 
As regards nitric id the consideration suggested by Prof. 
Johnson himself, viz, that its quantity must be exceedingl 
Variable, within short peri in one and the same so 
Seems to me a sufficient dispensation from the laborious 
etermination. 2 
The same holds good, in a measure, for ammonia. Its quan- 
