1799: ] 
duced toa dark coloured femitran{parent 
glafs, adhering pretty clofely to the tube. 
i was.able, however, to feparate them ; 
and [ am confident that the calx did not 
weigh more than the metal had done, 
whereas, computing from the proportion 
of 85 parts of oxygen to 15 of hydrogen 
(into which it is faid that water is reiol- 
vable)it will be found that it ought to have 
gained about 100 grains. Since then this 
great proportion of oxygen is not found, 
either in the calx, or in the water (for 
this alfo ITexamined) where will the an- 
tiphlogiftians fay that we are to look for 
it? For fince the water, they fay, is de- 
compofed to furnifh the inflammable air, 
it muft be fomewhere. 
3- Thave alforepeated the experiment of 
the revival of red precipitate in inflamma- 
ble air over mercury ; obferving particu- 
larly that there was neither fixed air, nor 
any ienfible quantity of wat:r produced, 
though much inflammable air difappeared. 
This air, therefore, mutt have entered 
nito the mercury that was revived, and 
did not unite with any thing that was ex- 
pelled from the precipitate. 
A. It is faid by the antiphlogiftians, 
that {pirit of nitre never becomes coloured 
by imbibing any thing, but always in 
confequence of giving out oxygen. [ 
think, however, that the contrary is 
proved by its decompofing nitrous air. 
But the fame effect is produced, though 
not in fo remarkable a manner, by means 
of inflammable air. I puta quantity of 
dephlogifticated fpirit of nitre into a phial 
with a ground glais ftopper with inflam- 
mable air on its furface; and in another 
fimilar phial atmofpherical air was con- 
fined with it. Both of thefe phials I 
covered with water in inverted glats jars, 
to prevent their having any communica- 
tion with the atmofphere. After long ex- 
pofure in thefe circumftances, that which 
had the common air on its furface never 
acquired any colour, or only a very little, 
from the effect of light tranfmitted through 
two glaffes with water between them; but 
that on the furface of which the inflam- 
mable air was incumbent, acquired colour 
very foon. I alfo found, onrepeating the 
experiment, that a part of the inflammable 
air had been imbibed by the acid. To 
make this experiment, a phial filled with 
the acid muft be introduced into a jar of 
inflammable air, and part of it being 
poured out, the ftopper muft be put into it 
in that fituation. Other precautions 
muft be ufed which a little experience will 
teach. 
5. Icannot help thinking that many 
@{ my experiments prove the generation of 
Dr. Priefiley on the Doétrine of Phlogifton. 
355 
both fixed air and phlogifticated air, from 
the iame elements, viz. dephlogifticated 
and inflammable air, or philogifton ; 
whereas the antiphlogittians fay that fixed 
air can only be produced by the union of 
carbone, or charcoal, with pure air; and 
that phlogifticated air is a fimple fub- 
fiance, called by them azote. I fhall, 
however, mention a few more obfervations 
which I think fupport what I have ad- 
vanced on this fubject. 
Having made much ufe of a mixture of 
iron hlings and fulphur, for the purpofe 
of phlogitticating air, I have always had 
a large quantity which had been long 
expoifed to the atmolphere, from which it 
is allowed that it attracts nothing befides 
dephlogilticated air. Of this mixture, 
then quite dry and brown, 34 ounces ex- 
poled to heat in an earthen tube gave 120 
ounce meafurcs of air, of which about 
one tenth was fixed air, and the reft almoft 
wholly phlogitticated. Both thefe kinds 
of air, theretere, muft cenfift of dephlo- 
gifticated air from the atmofphere, and 
fomething contained in. the iron or ful- 
phur, both of which are maintained to be 
fimple fubftances. There remained a black 
powder ftrongly attracted by the magnet. 
6. In general, iron filings and fulphur 
immerfed in mercury or water, or piaced— 
ina vacuum, yicld inflammable air ; but in 
fome cafes (though I do not know the 
reafon of the difference) this mixture has 
yielded phlogifticated air. Having placed 
a pot containing this mixture in a vacuum, 
T found, after fomedays, that it had yielded 
2% ounce meafures of air; and examining 
it I tound it to be completely phlogiiti-. 
cated. then put the fame mixture under | 
water, and placing it near the fire, it gave 
an ounce mzafure more, all phlogi.ticated. 
At another time, two ounce meafures of 
air was yielded by a mixture of this kind, 
and being examined long after it was 
formed, it was found to be wholly phlo- 
gilticated. It might, however, have been 
inflammable air which had undergone that 
change. 
7- Froma quantity of calx of lead, 
part grey and part yellow, ina glafs tube, 
I got about its bulk of almoit pure fixed 
au; and the refiduum extineuiihed a 
candle. Where could be the carbone in 
this cafe ? 
8. A folution of copper in volatile 
alkali, gave phlogifticated air with the 
marine acid; and it will not be eafy to 
fay where this azote exifted betore the 
procels. 
g. It is generally thought thet the 
fixed air contained in fallen time has been 
aitracted from the atmofphere, in which 
is 
