230 
CAPTAIN NOBLE AND MR. F. A. ABEL ON FIRED GUNPOWDER, 
It is of high importance to observe that the volume of the permanent gases gene¬ 
rated is in every case in inverse ratio to the units of heat evolved. Thus, if Tables 
Y. and VII. be compared, and if from Table V. we arrange the powders in descending 
order of units of heat, we have the order exhibited in Table VIII. ; and if from 
Table VII. we place the powders in ascending order of volumes of gas produced, we 
find that we have precisely the same arrangement. 
Table VIII.—Showing the arrangement of the six powders when placed either 
according to the amount of heat generated in a descending, or according to the 
quantity of gas evolved in an ascending, scale. 
Nature of powder. 
Units of heat, 
per gramme 
exploded. 
Cubic cents, of 
gas per gramme 
exploded. 
Spanish pellet powder 
767-3 
234-2 
Curtis and Harvey’s No. 6 powder 
764 - 4 
241-0 
W. A. F. G. powder 
738-3 
263-1 
W. A. R. L. G. powder . . 
725*7 
274-2 
W. A. pebble powder 
721-4 
278-3 
Mining powder . . 
516-8 
360-3 
The results given in this table are very striking. If we take the two natures 
which commence and close the list, it will be observed that on the one hand the heat 
generated by the Spanish powder is about 50 per cent, higher than that generated by 
the mining powder, and that on the other hand the quantity of permanent gases 
evolved by the mining powder is about 50 per cent, greater than that given off by 
the Spanish. 
Thus it appears that the great inferiority of heat developed by the mining as 
compared with the Spanish powder is compensated, or at least approximately so, by 
the great superiority in volume of permanent gases produced. A similar relation 
is observed in respect to the other powders, and it may indeed be noted that the 
products of the figures given in columns 2 and 3 in Table VIII. do not differ greatly 
from a constant value; thus pointing towards the conclusion that the pressures at 
any given density and the capacity for performing work of the various powders are 
not very materially different. 
This fact lias been entirely verified for the whole of the Waltham Abbey powders, 
and in a less degree for the three other powders also. 
Thus at the points where the Spanish, mining, and Curtis and Harvey’s No. 6 
powders have been compared with the standard pressure curves determined from 
and pressure specified, is equivalent to tlie assertion that the permanent gases occupy 278 - 3 times the space 
which the powder occupied in its unexploded state, the gravimetric density of the powder being assumed 
to be unity. 
