4io Dr. Priestley’s Experiments relating to Phlogijlon , 
ffream of nitrous vapour into a large phial previoufly filled 
with inflammable air. In this manner nitrous air is inilantly 
formed, and in great quantities ; but as this nitrous vapour is 
produced by the rapid iolution of bifmuth in 1 pi l it of nitre, 
which at the fame time produces a quantity of nitrous air, the 
experiment is not quite unexceptionable. I therefore attempted 
the fame thing in the following manner. 
Taking a quantity of what I have called a nitrated calx of 
lead, which I firft produced by uniting nitrous vapour to mi- 
nium (in confequence of which, from being a red and pow- 
dery fubfhmce, it became white, compact, and brittle), I placed 
it upon a (land, in a receiver filled with inflammable air, and 
throwing the focus of the lens upon it, there was a diminution 
of the inflammable air, which amounted to about two-thirds 
of the whole, and during this time lead was revived from the 
calx. After tins there was no more diminution of the air, or 
revival of the calx : and then examining what remained of 
the air, I found it to be all ffrongly nitrous : and, from the cir- 
cumfbmces in which it was produced, it muff have been formed 
from the nitrous vapour contained in the calx, and the in- 
flammable air in the receiver. In order to afeertain the purity 
of this nitrous air, I mixed it with an equal quantity of com- 
mon air, and found that they occupied the fpace of 1,32 mea- 
fures. Frefh nitrous air, made in the ufual way, and mixed 
with common air in the fame proportion, occupied the fpace of 
1,26. This difference arofe not from any impurity in the ni- 
trous air, but from the mixture of the dephlogifiicated air, 
which is alfo expelled from this calx by heat. 
Liver of fulphur was procured by throwing the focus of the 
lens upon vitriolated tartar in inflammable air, and it appeared 
to be perfe&ly well formed. 
Laflly, 
