3. 
mostly nitric oxyd,—and the formation of an acid, normal, basi 
or rusty pernitrate, or of a mixture of protonitrate and per- 
nitrate. 
_4.—Hydrogen may be given off continuously, while a proto- 
nitrate is formed. 
.—Hydrogen may be evolved rapidly at first and then more 
and more slowly till there comes a pause; after which the re- 
action changes and nitric oxyd is liberated abundantly, a per- | 
nitrate being the final product. : 
.—A very small portion of the acid may be decomposed so | 
as to generate nitrate of ammonia; and this can take place 
while nitric oxyd, or hydrogen, or no gas at all is given off. 
-—During a moderate action there may be an absorption of 
oxygen from the air, and consequently a greater amount of oxy- 
dation will ensue than can be accounted for by the gases extri- 
cated and the nitrate of ammonia formed. 
Pernitrate solutions made with weak acid and excess of iron 
€ proneness of ails acid to dissolve an excess of iron, 
_ Tenders it hardly possible to make directly a solution that shall 
contain an exact normal nitrate; for even if we try to use the 
Precise quantities of material which theory would indicate, the 
_ Teaction is not simple enough to allow us to predict just how EY 
- much acid will be consumed in effecting the oxydation. Yet the a 
» Ann., xxxix, 141. 1 Annalen der Ch. and Ph., Lxxxix, 10 
Serres, Vou. XL, No. 120.—Nov., 1865. : : 
