and the feemmg Conversion of Water into Air, 4 1 r 
Laftly, to produc t fulphur r I threw the focus of the lens oil 
a quantity of oil of vitriol, contained in an hollow earthen 
vefiel, and evaporated it to drynefs in a receiver filled with in- 
flammable air, in confequence of which the infide of the re- 
ceiver acquired a whitifh incruftation, which when warmed, 
had a ftrong fmell of fulphur ; and repeating the procefs in the 
fame receiver, I was able, this fecond time, to lerape off 
enough of the matter to put on a piece of hot iron, and to 
produce the genuine blue flame, as well as the peculiar fmell of 
fulphur. 
I fhall conclude thefe obfervations on phlogifton with two 
articles one of which feems to contradict an effablifhed maxim- 
among chemifts ; and the other a former opinion of my own. 
It is generally faid, that charcoal is indeftruftible, except bv 
a red heat in. contact with air. But I find that it is perfeCtlv 
deftruCtible, or decompofed, in vacuo , and by the heat of a 
burning lens almoft wholly converted into inflammable air; fo 
that nothing remains befides an exceedingly fmall quantity of 
white allies, which are leldom vifible, except when, in very 
fmall particles, they happen to crofs the fun-beam, as they flv 
about within the receiver. It would be impoflible to collect or 
weigh them ; but, according to appearance, the allies thus pro- 
duced from many pounds of wood could not be fuppofed to 
weigh a grain. The great weight of allies produced by burn- 
ing wood in the open air arifes from what is attracted by them 
from the air. The air which I get in this manner is wholly 
inflammable, without the leaft particle of fixed air in it. But, in 
order to this, the charcoal mult be perfectly well made, or with 
l'uch a heat as would expel all the fixed air which the wood 
contains; and it muff be continued till it yield inflammable air 
only, which, in an earthen retort, is loon produced. 
Wood, 
