4i 6 Dr. Priestley’s 'Experiments relating to Thlogifton , 
I had, however, been fo often favoured with valuable refults 
from merely putting things into new fituations, that I was 
encouraged to make the experiment ; but I found an unexpected 
difficulty in getting a cock that would be air-tight and fleam- 
tight under fo great a preffure as I wifhed to apply. 
I was mentioning thefe ideas to Mr. watt, in whofe neigh- 
bourhood 1 have the happinefs to be f tuated, when he men- 
tioned a fimilar idea of his, viz. that of the poffibility of the 
converfion of water, or fleam, into permanent air ; faying, 
that fome appearances in the working of his fire-engine had 
led him to ex peel this. He thought that if fleam could be 
made red-hot, fo that all its latent heat ffiould be converted 
into lenfible heat, either this or fome other change would 
probably take place in its conflitution. The idea was new to 
me, and led me to attend more particularly to my former pro- 
jects of a fimilar nature, and I began with lime-flone, wiffi- 
ing to try the effefl of giving a red heat to lime in which water 
only ffiould be previoufly combined, thinking it might poffibly 
have the fame effedt with making the water itfelf red hot. 
Accordingly, I took a quantity of well calcined lime, and mix- 
ing with it a little water, out of which all air had been carefully 
boiled, I expofed it gradually to a ftrpng heat in an earthen 
retort, fuch as I had been ufually fupplied with by Mr. Wedg- 
wood (who is as much diffiinguiffied by his love and generous 
encouragement of fcience, as he is by his improvements in his 
own curious art), not imagining that it could make any dif- 
ference whether the lime, fo prepared, ffiould receive its heat 
in an earthen retort, or in a veflel of iron or glafs. Proceed- 
ing, however, in this manner, I found that nothing came over 
in the form of Jleam , but that there was a great quantity of aii\ 
fever al hundred times more than the bulk of the water, and at 
5 ..■ K *!*that 
