and the feemtng Converfan of IV a ter into Air. 42l 
got in the eaithen retort, and not much worie than that of the 
atmofphere. 
Another circumflance I obfervcd was, that if the outfide of 
the veflel which contained the water or fleam, through which 
it paiTed, when the rCquifite heat was applied to it,° was not 
dry, or perhaps 1'urrounded with good air (for in thole circum- 
fhances the following experiment differs from the preceding 
ones) the experiment did not Succeed. 
When I put the ball of an ear them retort, filled with moifl 
clay, into an iron digefler, and applied heat to it, I get only a 
very little fixed air, which was probably compofed of a Small 
quantity of air beginning to be produced from the materials 
and inflammable air from the veflel. All that come over be- 
Sides was fleam, and at lafl inflammable air, from the veflel 
itfelf. 
Being now able to procure air by means of water in this 
mofl Ample method, viz. by water only in the earthen retort, 
I had an opportunity of ascertaining, with great eale and exaCl- 
neSs, Several circumflances relating to the procefs, and of ob- 
viating, as 1 thought, Some objections to the concluflon that I 
had drawn from it. Among other things I fully fatisAed my- 
felf that the earth of the retort contributed nothing at all to 
this production of air, but the water only : for having ufed the 
fame retort till 1 had got from it nearly an ounce weight of air, 
or 800 ounce meafures, I found that it had not loft l'o much as 
a Single grain in weight. After the flrfl procefs it weighed juft 
three grains more than it did at flrfl, and it continued to weigh 
the Aime till after the lafl procefs. This Small addition of 
weight might eaAly have come from a little of the water hav- 
ing been imbibed by the neck of the retort, where the heat of 
the Are could not reach it. When all the procefles were over, 
I kept 
