226 CAPTAIN NOBLE AND MR. F. A. ABEL ON FIRED GUNPOWDER. 
With the small explosion-vessel the results obtained (experiments 146 to 166) were 
as follows, the numbers given below indicating the gramme units of heat evolved by 
the combustion of 1 gramme of each description of powder employed :— 
Nature of powder. 
Gramme-units of heat evolved. 
I. 
II. 
III. 
IV. 
Means. 
Pebble. 
711-9 
734-1 
694'4 
710-0 
712-6 
R, L. G. 
725-1 
718-4 
707-5 
, , 
717-0 
F. G. 
706"5 
738-9 
731-7 
725-7 
Curtis and Harvey's No. G . 
784-0 
755'7 
744-9 
732-9 
i 0-4? 3 
Mining. 
512-7 
505"5 
507"9 
508" 7 
Spanish. 
762-5 
771-4 
753-4 
762-4 
With the larger explosion-vessel the results of experiments 171 to 179 and 181 
to 192 gave 
Nature of powder. 
Gramme-units of heat evolved. 
I. 
II. 
ITT. 
Means. 
Pebble . . . 
728-5 
714-7 
703-4 
715"5 
R. L. G. 
713-4 
724-7 
717-7 
718-6 
F. G. 
7311 
722-1 
730-7 
728-0 
Curtis and Harvey’s No. 6 . 
751-3 
765-3 
750-6 
756-1 
Mining. 
520-0 
507-0 
499-6 
508-9 
Spanish. 
771-3 
761-8 
754'0 
762-3 
From the whole of these experiments, and giving to the second series, as probably 
the more accurate, twice the weight of the first series, we arrive at the conclusion that 
the heat generated by the combustion of the powders as actually used is as follows :— 
1 gramme of pebble powder generates 714'5 gramme-units 
1 
33 
,, R. L. G. „ 
33 
718-1 
1 
33 
„ F. G. „ 
33 
727-2 
1 
33 
,, C. and H. No. 6 
33 
755-5 
1 
33 
„ mining „ 
3 3 
508-8 
1 
33 
,, Spanish ,, 
33 
762-3 
From an examination of the whole of the above results it is obvious: Firstly, that 
the heat generated by the combustion of gunpowder is subject to very wide varia¬ 
tions, dependent upon the particular nature* of the powder employed (the Spanish 
* Both physical and chemical. 
