97 
and the Mode of its Communication. 
with warm clothing, I found, by taking the mean of the results 
of several experiments, that it required 55-§ minutes to cool 
through the same interval. 
On measuring the instrument with care, I found its dimen- 
sions to be as follows. 
Inches. 
Diameter of the body of the instrument - =4.03 
Length of the body - - - = 3.96 
Diameter of the neck of the instrument - =0.8 
Length of the neck - - - - =4. 
The superficies of the different parts of the instrument are 
therefore as follows. 
Superficies of the vertical sides of the body ( = 4.03x3.14159 
x 3.96) = 50.136 inches. 
Superficies of the flat circular bottom of the instrument, 
( = 4.03 x 3.14159 x^p)— 1 2.755 inches ; deducting nothing 
for that part which is covered by the end of the tube, which 
serves as a support for the instrument. 
Superficies of the flat circular top of the instrument, (after 
deducting 0.502 of a superficial inch, for the circular hole in its 
centre, made to receive the lower end of the cylindrical neck,) 
= 12.253 inches.. 
Superficies of the cylindrical neck of the instrument (= 0.8 
x 3.14159 x 4) = 10.051 inches. 
Supposing now, that the heat passes with equal velocity through 
the surface of all the different parts of the instrument, when the 
instrument is naked, we can determine the quantity of heat 
which escaped through the ends and neck of the instrument, in 
the experiments in which those parts of the instrument were 
covered with warm clothing. 
mdccciv. O 
