4 20 Mr. de Luc 
of that increase of moisture was, the diminution of its mo- 
dule by that of heat. 
In respect of air, its quantity was so diminished, as to per- 
mit a column of quicksilver of 26 inches to rise in the long 
gage. 
The pump was again worked, and time given for the in- 
struments to settle. 
7,25' 28,7 — 96,5 47,75 
The original temperature was now restored ; and as air had 
been much diminished by the first operation, fire, thus much 
more free in this, escaped the action of the pump. Mois- 
ture also was restored nearly to its original degree, though 
very little air remained in the receiver. 
The pump was worked by intervals. 
10,5' 28,5 0,70 95,66 47,75 
The quantity of air was now so little, that it cannot be 
supposed to have had any share in the effect of the steam ; 
however moisture remained sensibly the same by the same 
temperature. 
Worked again the pump to the best vacuum. 
10,10 28,7 0,53 94,5 48,8 
The pressure on the short gage was now, according to Mr. 
Nairne’s experiments, almost wholly produced by steam ; 
yet moisture preserved its own distinct modifications : here it 
is diminished, notwithstanding the maximum of evaporation, 
because of the increase of heat. 
The pump was worked at different times, for extract- 
ing some air that was disengaging itself from the large wet 
cloth. 
