37 6 Mr. cavendish’s Account of 
never fhines on the thermometer itfelf, or that part of the 
wall dole to it, except in the afternoon, long after the 
time of obferving. On the whole, the lituation is not 
altogether fuch as could be wifhed, but is the belt the 
ho ule afforded. 
The thermometer within doors is intended chiefly for 
J 
correcting the heights of the barometer, and is therefore 
placed clofe to it. The room in which it is kept looks to 
the North, and has fometimes a fire in it, but not often. 
It has been too common a cuftom, both in making ex- 
periments with thermometers and in adjufting their fixed 
points, to pay no regard to the heat of that part of the 
quickfilver which is contained in the tube, though this is a 
circumftance which ought by no means to be dilr egarded ; 
for a thermometer, dipped into a liquor of the heat of boil- 
ing water, will hand at leaft 2 0 higher, if it is immerfed to 
fuch a depth that the quickfilver in the tube is heated to 
the fame degree as that in the ball, than if it is immerfed 
no lower than the freezing point, and the reft of the tube 
is not much warmer than the air. The only accurate 
method is, to take care that all parts of the quickfilver 
fhould be heated equally. For this reafon, in trying the 
heat of liquors much hotter or colder than the air, the 
thermometer ought, if poflible, to be immerfed almoft 
as far as to the top of the column of quickfilver in the 
tube. As this, however, would frequently be attended 
with great inconvenience, the obferver will often be 
obliged to content himfelf with immerfing it to a much 
lefs depth; but then, as the quickfilver in a great part of 
the 
