14P Count Rumford's Enquiry concerning the Nature of Heat , 
to do, by comparing the results of those experiments, with the 
results of some other experiments of a similar nature. 
In the experiment No. 28, a cylindrical vessel of thin sheet 
brass, 4 inches in diameter, and 4 inches in height, covered with 
gold-beater's skin painted black with Indian ink, being filled 
with hot water, and exposed to cool in the air of a large quiet 
room, cooled from the point of 50 degrees to that of 40 degrees 
above the temperature of the air of the room, in 23^ minutes. 
The quantity of surface by which this vessel was exposed to 
the cold air, was = 74.5581 superficial inches, exclusive of its 
neck, which was well covered up with fur. 
The quantity of surface which was exposed to the air, in the 
foregoing experiments with the conical vessels, or the area of 
the bottom of each of the vessels, was (4 x 3*14,159) = 12.42% 
superficial inches. 
As the diameters and heights of the conical and cylindrical 
vessels were equal, the contents of the former must have been 
to the contents of the latter as 1 to 3 ; and the quantities of heat 
which they lost in cooling were as their contents. 
If now the cylindrical vessel lost a quantity of heat = 3, in 
minutes, it would have disposed of a quantity = 1, (equal 
to that which the conical vessel lost,) in one-third part of that 
time, or in 7 minutes and 50 seconds. 
But the quantity of surface exposed to the air in the experi- 
ment with the cylindrical vessel, was to that so exposed in the 
experiment with the conical vessel, as 74.5581 to 12.4263, or 
as 6 to 1. 
Now, as the time in which any given quantity of heat can pass 
out of any closed vessel, into, or through, any cold fluid medium 
by which the vessel is surrounded, must be inversely as the 
