356 
ME. F. A. ABEL’S CONTRIBUTIONS TO 
instance, as regards the readiness with which it transmitted detonation. One grain 
(•065 grm.) of the fulminate, when detonated in one extremity of the tube 0*9 metre 
(35 inches) long, induced the detonation of fulminate in the other extremity ; whereas 
a similar result was only obtained with paper tubes O’ 3 metre (12 inches) long, the 
interior surfaces being composed of the comparatively rough brown paper. Again, a 
piece of brass tube, of the same description as that employed in the preceding experi- 
ments, the inner surface being dull and somewhat rough, was brightly polished inside. 
In this condition the tube transmitted detonation, developed by 1 grain (‘065 grm.) 
of silver fulminate, through a length of 36 inches (0'93 metre); whereas in the original 
condition, with the somewhat rough interior, it only transmitted the detonation deve- 
loped by 1 grain (-065 grm.) of the same batch of fulminate, with certainty, through a 
length of 19 inches (0'5 metre). 
The tubes of paper and of brass may therefore be considered to have been placed 
nearly on an equality with glass tubes of the same dimensions, as regards their power 
of transmitting detonation, by employing them with smooth interior surfaces. It may 
not be impossible that the slight superiority of the glass tubes in their power of trans- 
mitting detonation may still have been entirely due to the establishment of less friction 
between their inner surfaces and the gas-wave. 
The surfaces of the pewter tubes approached in smoothness those of the glass tubes ; 
and it will be seen (by reference to Table I.) that these tubes did not differ from each 
other considerably as regards the facility with which detonation was transmitted 
through them. Several attempts were made to impart a smooth interior to the india- 
rubber tubes by coating them with varnishes of considerable body ; no very satisfactory 
result was obtained ; but the smoothest of the varnished tubes afforded decided indica- 
tions that the transmission of detonation was favoured, though only to a comparatively 
slight extent, by the diminution in roughness of the interior. In some experiments 
one extremity of the tubes was lined with sheet copper just at the seat of the initiative 
detonation, but the results were not at all affected thereby. The conclusion appears 
warranted, that with india-rubber tubes the effect of the detonation upon the material 
composing the tube operates in a manner decidedly antagonistic to the transmission of 
detonation : one cause of this is, no doubt, the comparative readiness with which the 
sides of the tubes yield to the pressure of the gas-wave, and the consequent considerable 
lateral expenditure of force. The particles of the tube appeared themselves to be set 
in violent and irregular motion by the explosion ; the tubes were always thrown into 
contortions, and violently jerked out of position, by the initiative detonation * ; while 
with tubes of other materials only those portions were projected which were actually 
destroyed by the explosions, the tube itself remaining undisturbed. 
* In some of the experiments these tubes were strongly attached to hoards by means of strappings of wire 
placed at short intervals ; but the results were not affected thereby. 
