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VIII. Researches on Explosives. No. II .—Fired Gunpowder. 
By Captain Noble (late R.A.), F.R.S., F.R.A.S., F.C.S., Ac., and F. A. Abel, 
C.B., F.R.S., V.P.C.S., Ac., Ac. 
Received May 21,—Read May 29, 1879. 
Contents. 
Page 
Criticisms on the first memoir of the authors 
by the Commission appointed by the Aca¬ 
demic des Sciences . 204 
Statement of mean results of analysis of the 
gaseous and solid products of explosion of 
all the descriptions of powder experimented 
with . 206 
Complete tabular statement of results of 
analysis of products obtained at different 
densities. 207 
Discussion of M. Berthelot’s views as to the 
expression of the decomposition of gun¬ 
powder . 208 
Observations relating to the formation of 
potassium hyposulphite . 211 
Special experiments relating to this point . . 213 
Further analysis of R. L. G. powder used in 
the experiments. 217 
Composition of other gunpowders used in 
later experiments. 218 
Results furnished by these. 219 
General observations on the complete analy¬ 
tical results . 220 
Further experiments on the determination of 
heat generated by fired gunpowder . 223 
Tabulated results of heat determinations.... 227 
Results of calculation of the mean specific 
heats of the products of explosion. 228 
Volumes of permanent gases generated by 
different powders. 229 
Page 
Relation of volumes of permanent gases to 
the units of heat evolved. 230 
Pressures given by mining powder and Wal¬ 
tham Abbey powder. 231 
Actual temperatures of explosion. 232 
Relation between tension of the gases deve¬ 
loped in a gun and the volume which they 
occupy . 232 
Table of tensions of the gases (1) in a gun 
and (2) if allowed to expand without pro¬ 
duction of work . 235 
Table showing total work performed in a gun 
by Waltham Abbey powder . 236 
Application of this table. 239 
Effects of retention of the shot in the chamber 
of a gun upon the tensions developed .... 242 
Estimation of the position of the shot in a 
gun’s bore when complete combustion has 
been effected. 244 
Concluding remarks. 245 
Appended memorandum of proportions of 
elements found in each product of explo¬ 
sion, and existing in the original powder.. 246 
Abstract of experiments. 262 
Note with respect to hyposulphite. 277 
Products of explosion calculated on the suppo¬ 
sition that all hyposulphite found originally 
existed as sulphides. 278 
During the course of the experiments that we have undertaken in extending our re¬ 
searches on explosives to the investigation of the action and results of fired gun-cotton, 
we have had occasion to examine some points connected with the subject of our former 
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