95 
the Source of the Heat excited by Friction. 
wax (= 2303.8 grains) necessary to produce the quantity of 
heat actually obtained by friction in the experiment in ques- 
tion, and in the given time, (150 minutes,) nine candles , burn- 
ing at once, would not be sufficient ; for, 9 multiplied into 245 
(the number of grains consumed by each candle in 150 mi- 
nutes) amounts to no more than 2205 grains; whereas the 
quantity of wax necessary to be burnt, in order to produce the 
given quantity of heat, was found to be 2303.8 grains. 
From the result of these computations it appears, that the 
quantity of heat produced equably, or in a continual stream, 
(if I may use that expression,) by the friction of the blunt steel 
borer against the bottom of the hollow metallic cylinder, in the 
experiment under consideration, was greater than that produced 
equably in the combustion of nine wax candles , each -J of an 
inch in diameter, all burning together, or at the same time, 
with clear bright flames. 
As the machinery used in this experiment could easily be 
carried round by the force of one horse, (though, to render the 
work lighter, two horses were actually employed in doing it,) 
these computations show further how large a quantity of heat 
might be produced, by proper mechanical contrivance, merely 
by the strength of a horse, without either fire, light, combus- 
tion, or chemical decomposition ; and, in a case of necessity, 
the heat thus produced might be used in cooking victuals. 
But no circumstances can be imagined, in which this method 
of procuring heat would not be disadvantageous ; for, more 
heat might be obtained by using the fodder necessary for the 
support of a horse, as fuel. 
As soon as the last mentioned experiment (No. 3.) was 
finished, the water in the wooden box was let off’, and the box 
