and the feem'mg Conversion of Water* into Air. 425 
it might be laid that I only expelled the air before contained in 
the water, though from thefe experiments it appeared to con- 
tain much more air than it had been thought capable of con- 
taining. .To obviate this objeflion, I contrived to catch all the 
water that efcaped through the pores of the retort in the fol- 
lowing manner. 
Having put the moiftened clay in an earthen tube, to which 
I had fitted a cock and a long glafs tube (by means of which I 
could colled! all the air that came from it), I put this within 
cr 1 it on time, which was doled at the end next the fire, but 
open at the other end, and fo long that I could eafily keep this 
open and quite cool while the other was in the fire-; confe- 
quently, whatever water efcaped through the pores of the 
earthen tube, it would be condenfcd in the cool part of the iron 
one. This water I carefully collected, and always found that 
the weight ol it, together with that of the air produced in the 
experiment, was nearly that of the original weight of the 
water, eft i mated by the lofs of weight in the earthen tube and 
its contents. I alio found, that the water fo collected ferved 
for the production of more air, juft as well as any other water 
whatever, fo that there had been no decompofition of the water 
in the cafe. 
In the laft procefs that I went through of this kind, the 
lofs of weight in the earthen tube, or rather of the water con- 
tained in it, was 12 dvvts. 4 grs ; the air collected was 173 
ounce mealuies, which would have weighed 4 dvvts. 3 grs. and 
the water which efcaped through the pores of the earthen tube, 
and which I colleded, was nearly 8 dwts. 3 grs. ; fo that the 
air and this w^ater together weighed 12 dwts, 14 grs. or ten 
grains more than the original water. But as I eftimated the 
weight of the water only by the fpace which it occupied in a 
K k k 2 cylin- 
