Parts of Water and of Dephlosifticated Air. 343 
latter circumftance’ is effentially neceflary to be attended to. 
An ounce of the cryftals of mineral alkali were diffolved in 
nitrous acid, and.the mixture brought to an exact faturation by 
the teft of litmus; 30 ounce meafures of air were diftilled from 
it, which, during the latter part of the procefs, was accom- 
panied with flightly yellow fumes; the receiving water was 
found to be acid, and the refiduum alkaline. he refiduum 
being diffolved in the receiving water, the folution was neu- 
tral, or very nearly fo, by every teft; for in this cafe litmus. 
might be ufed, asthe acid was very flightly phlogifticated. On 
adding a few drops of a very dilute nitrous acid, the tefts 
fhewed the liquor to be acid. 
12. Encouraged by the fuccefs of this experiment, I took 
an ounce= 480 grains of pure common nitre, and put it into a 
flint-glafs retort, coated, which was placed in a furnace. It 
began to give air about the time it became red-hot, and during © 
the latter part of the procefs this air was accompanied with 
yellowifh fumes.’ I ftopped the procefs when it had produced, 
$0 ounce meafures of air. The receiving water, and parti- 
cularly the air, had a ftrong but peculiar {mell of nitrous acid. 
The air was well wafhed with the receiving water, but was 
not freed from the fmell. The receiving water, which was 
50 ounces, was flightly acid, and the refiduum alkaline. I 
diffolved the latter in the former, and found the mixture alka- 
line. 10 grains of weak nitrous acid were added to. it, which 
faturated it, and105 grains of this fpirit of nitre was found to 
contain the acid of 60 grains of nitre; therefore the Io grains 
contained the acid of 5,7 grains of nitre, which, by Mr. Kir- 
WAN’s experiments is equal to two grains of real nitrous acid. 
We have, therefore, 34 grains weight of dephlogifucated air 
produced, and only two grains of real acid miffing ;, and it is not 
certala, 
