844 Report of the Committee 
quickfllver in the tube is cooler than that in the ball, and 
fubtraCted when it is warmer : for example, let the ob- 
ferved heat of the fluid be 47 5 0 , let the thermometer be 
immerfed in the fluid as far as to the degree of 25 0 , or 
to that part of the tube which fhould be marked 25 0 if 
the divifions were continued long enough ; then is the 
number of degrees in that part of the tube which is not 
immerfed in the fluid 45 o ; and let the heat of the quick- 
lilver in that part of the tube be fuppofed ioo°; and 
confequently, the difference of heat of the quickfilver in 
that part of the tube from that in the ball 375 ; then in 
the left-hand perpendicular column feek the number 
450, and in the upper horizontal line the number 375; 
the correfponding number in the table, or the correction, 
is 1 5 0 , and therefore the true heat of the fluid is 49 o°. 
This correction may be had very eafily without the 
help of the table, only by multiplying the number of 
degrees not immerfed in the fluid by the fuppofed dif- 
ference of heat, dividing the produCt by 10000, and 
diminifhing the quotient by one-eighth part of the 
whole. 
In the following pages we have thrown together the 
practical rules, which we would recommend to be ob- 
ferved in adjufting the fixed points of thermometers. 
4 Rules 
