| 
} 
: 
S. P. Sadtler on Fischer's Salt. 191 
and then deposited steadily though slowly. After a number 
of hours not the slightest’ bubble of air was to be seen. The 
absence of all chance of oxydation here, either from air or 
tion of gas exceedingly rapid. Before drawing any conclusions 
from this, howetei t e ne of acetic acid on KN ®,, out of 
access of air, was to be studied. Gmelin* states that, when 
treated with acid out of access of air, nitric oxyd is evolved 
while the liquid takes up N®, and N,0; This evolution was 
found to take place readily over the mercury and the gas 
answered to the test of ferrous sulphate and was colored red 
on admission of air, like the gas evolved in the formation of 
the salt. The question now is whether the liberated © is taken 
Up in the formation of the salt to oxydize the €o®, to convert 
the excess of nitrite into nitrate. “The question cannot be 
€finitely settled, until we have some delicate test for a small 
quantity of nitrate in the presence of a large quantity of 
nitrite. But there is one thing which I as sign cant. 
rdmann made one of his preparations of the “acid salt,” b 
filtering the mixture of neutral solutions into pure acetic 
Now the greater the excess of acid, the quicker would be the 
Conversion of nitrite into nitrate, and we should look for a very 
Small amount of the double nitrite salt. Yet it formed as 
readily, and analysis proved it to possess the same constitution 
4s the other preparations. The inference from this is, that the 
* Cay. Soc. ed. vol. ii, p. 382. 
