his Thermometer with the common mercutial ones. 3.65 
filver by this heat, that is, by an increafe of the heat from 50° 
to 212°, or a period containing 162° of FAHRENHEIT, was” 
juit 8° of the gage or intermediate thermometer M; whence 
one of thefe degrees, according to this experiment, containg 
joft 20°: of Faurenuert’s. The operation was many times 
‘repeated, and the refult was always precifely the fame. | 
For the boiling heat of mercury, it was neceflary to A al 
ina different manner; not to convey the heat from the mer- 
cury to the inftrument, but to convey it equally to them both 
from another body. _ I made a {mall veflel for holding the mer- 
cury in the gage itfelf, feen at K fig. 4. and more diftin€tly in 
fig. 5. which is a tranfverfe feCtion of the gage through this 
veflel. The plate CD, which forms the bottom of the canal, 
ferves alfo for the bottom of the veflel, which is fituated clofe 
to the fide of the canal, and as near as could be to that part of 
it, in which both the filver piece, and the divifions required) 
for this particular experiment, are contained. By this arrange- 
ment it 1s pretumed, that all the parts concerned in 1 the meee 
tion will receive very nearly an equal heat. 
The gage, with fome mercury in the veffel, was laid upon a 
fmooth and level bed of fand, on the bottom of) am iron muffle 
kept open at one end; the fire increafed very gradually till the. 
mercury boiled, and then continued fteady, fo as juft to keep 
it boiling, for a confiderable time. The boiling heat of mercury 
was thus found to be 27°4 of the intermediate thermometer, 
which anfwering to an interval of 550° of FaHRENHEIT, 
makes one degree of this equal to juft 20° of his; a refult cor- 
refponding even beyond my expectations with that which 
boiling water had given. 
Thete ftandard heats of FAHRENHEIT’S shiecaocinene are ob- 
tained with little difficulty on a common fire; but it is far 
otherwife 

