Experiments upon Heat . 295 
ehoaks, in the inftruments N r. and N° 2. or with the 
branches of the fteel fpring in N" 3. and from thence commu- 
nicated to the bulb, muft have been exceedingly {mail; yet I 
was defirous to prevent even that, and every other pollible 
error or inaccuracy, however fmall, that might arife* 
Does humidity augment the conducting power of air ? 
To determine this queftion I made the following experir 
ments, the weather being clear and fine, the mercury in the 
barometer handing at 27 inches 8 lines, the thermometer at 
1 9 0 , and the hygrometer at 44 0 *. 
(Exp. N° 17.) 
\ Thermometer N° 4. 
Surrounded by air dry to the 
44th degree of the quill hy- 
grometer of the Manheim 
Academy. 
Taken out of freezing water , 
and plunged into boiling water. 
(Exp. N° i 8.) 
The fame thermometer (N° 4.) 
Surrounded by air rendered 
as moijl as poffible by wetting 
the infide of the cylinder and 
globe with water. 
Taken out of freezing water, 
and plunged into boiling water • 
Time elapfed. Heat acquired. 
Time elapfed. 
Heat acquired. 
— — 
8o° 
o° 
M. S. 
0 
S. 
9 
O 34 
IO 
0 6 
ID 
O 39 
20 
0 4 
20 
O 44 
3 ° 
0 5 
' 3 ° 
° 5 1 
40 
0 9 
40 
1 6 
5 ° 
018 
J° 
1 35 
60 
0 26 
60 
2 40 
7 ° 
0 43 
70 
notobferved. 80 
7 45 
80 
8 9 
= total time of 
1 5 1 = 
total time of 
heating from 
0 '* 
0 
1 
0 
4 -> 
O 
heating from o' 
5 to 70° 
From, 
