224 
CAPTAIN NOBLE AND MR. F. A. ABEL ON FIRED GUNPOWDER. 
In fact, one of the principal objects of our experiments was to determine this very 
point, and we therefore considered it necessary, at all events in the first instance, to 
determine the heat generated when gunpowder is fired hi considerable quantities and 
under high tensions. 
To do this, vessels of great strength, consequently of great weight, and therefore 
not well suited for calorimetric observations, were necessary. 
It will presently be seen, however, that the difference between the determinations 
made by us and those of the other experimenters alluded to by General Morin and 
M. Berthelot are due, not to error in our determinations, but to essential and striking 
differences in the decomposition of different descriptions of powder. 
The conclusion of the whole of our analyses (of which a complete table is given 
at p. 207 of this memoir) has shown that, with certain slight exceptions, to which we 
have elsewhere adverted, the products of combustion are not seriously affected either 
by differences in the quantity or the gravimetric density of the charge exploded. It 
would appear indeed as if there were occasionally quite as great differences in the 
transformation which takes place between charges exploded as nearly as possible under 
the same circumstances and others exploded under widely different conditions. 
We were therefore enabled in the experiments which we are about to describe to 
make use of the following apparatus, 
