Experiment? upon Heat* 
perature of the water, I plunged it into boiling water, and 
obferved the times of the afeent of the mercury in 
the thermo- 
meter. They were as follows : 
Time 
Heat 
elapfed. 
acquired. 
Heat at the moment o£ being plunged into 
\ 
18 0 R. 
the boiling water, 
J 
> 
M. S. 
c • 
After having remained in the boiling water 
0 45 
27 
1 0 
34-rV 
2 10 
44t 9 o- 
2 40 
4»A 
4 0 
5 6 xV 
5 0 
^O-rV 
From the refult of thefe experiments It appears evidently, 
that the Torricellian vacuum, which affords fo ready a paflage 
to the electric fluid, fo far from being a good conduftor of heat r 
is a much worfe one than common air, which of itfelf is- 
reckoned among the worft : for in the laft experiment, when 
the bulb of the thermometer was furrounded with air, and the,, 
inftrument was plunged into baiting water, the mercury rofe 
from 18 0 to 27 0 in 45 feconds ; but in the former experiment, 
when it was furrounded by a Torricellian vacuum, it required 
to remain in the boiling water 1 minute 30 feconds = 90 feconds, 
to acquire that degree of heat. I11 the vacuum it required 5 
minutes to rife to 48 V-o ; but in air it rofe to that height in 
2 minutes 40 feconds; and the proportion of the times in. 
the other obfervations. is nearly the fame, as.will appear by the 
following table,.. 
The 
