Paris of Water and of Depblogificated Air. 3 
In order to examine whether this phlogiiton was furnithed by 
the earths, fome dephlogifticated nitrous acid was diftilled 
. from minium till no more acid or air came over. More of the 
fame acid was added to the minium as foon as it was cold, and 
the diftillation repeated, which produced the fame appearance 
of red fumes and dephlogifticated air. This cperation was re- 
peated a third time on the fame minium, without any fenfible 
variation in the phenomena. The procefs fhould have been 
ftill farther repeated, but the retort broke about the end of the 
third diftillation, The quantity of minium ufed was 120 
grains, and the quantity of nitrous acid added each time was 
240 grains, of fuch ftrength that it could diffolve half its 
weight of mercury, by means of heat. : 
It appears from this experiment, that unlefs minium be fuppofed 
to confift principally of phlogifion, the fource of the phlogifion, thus 
obtained, was either the nitrous acid itfelf, or the water with 
which it was diluted; or elfe that it came through the retort with 
the light, for the retort wasin this cafe red-hot before any air was 
produced; yet this latter conclufion does not appear very fatif- 
factory, when it is confidered, that in the procefs wherein the 
earth made ufe of was magnefia, the retort was not red-hot, or 
very obicurely fo, in any part of the procefs; and by no means 
luminous, when the yellow and red fumes firft made their 
appearance. 
g. As the principal point in view was to determine whether 
any part of the acid entered into the compofition of the air, I 
refolved to employ fome fubftance which would part with the 
acid in a moderate heat, and alfo give larger quantities of 
air than had been obtained in the former procefles. Mer- 
cury was thought a proper fubftance for this purpofe. 240 
parains of mercury were put into a glafs retort with 480 grains 
Viny. 2 of 
