ON PYROXYLIN. 
27 
Now we have shown that pyroxylin is sure to decompose with heat, that in some cases 
it detonates, and in others apparently identical it is destroyed without combustion. 
Why should it not be the same at a low temperature ? Why should we not add to the 
instances of simple decomposition those of detonation ? The analogy is so evident that 
we need not have recourse to the supposition of imperfect washing to explain the com¬ 
bustion of pyroxylin. 
The Hirtenberg pyroxylin itself exploded in the magazine at Simmering, and in the 
investigation made July 31, 1862, it was merely decided that the accident was due to 
spontaneous combustion. It has also been attributed to the ordinary powder also con¬ 
tained in the magazine, but this supposition is inadmissible, as, for several centuries, 
there has been no known instance of spontaneous combustion of gunpowder. We must 
not, of course, as was done in an Austrian paper, confound accidents during manufacture, 
carelessness of workmen, or faulty mechanism, with the explosions produced by no other 
cause than the reactions among the elements of the compound. 
Comparison of Lenk’s Pyroxylin with those of Bouchet relative to their Propulsive and 
Blasting Qualities. —It remains for us to give the results of the experiments made with 
Navet’s pendulum to compare the propelling powers of these two kinds of gun-cotton. 
Twenty-five charges were fired with Lenk’s pyroxylin, fifteen with those of Bouchet, 
three grammes for each charge, and round balls weighing each 25 grm. 50. 
Taking first the medium velocity of the balls, and then the greatest and the least, we 
have,— 
Gun-cotton, 
Hirtenberg. Bouchet. 
Medium velocity . . . 385-36 m. 394-32 m. 
Greatest „ .... 441-53 485*94 
Least „ .... 357-63 357*63 
Differences much greater than those presented by the above figures are sometimes found 
in firing from the same specimen. For instance, the pyroxylin brought from Austria by 
General Lenk was fired twice, giving:— 
On February 17th. 374*40 m. 
,, March 8th. 408-40 
From these results we may conclude that both kinds have the same ballistic force. 
In these experiments the gun w r as filled to the height of 0 05 m. It was proposed to 
ram it harder, reducing the height to 0'03 m.; but the first charge fired by this method, 
and with three grammes of General Lenk’s pyroxylin, burst the gun barrel. 
This accident has also happened in firing charges of the Bouchet pyroxylin, showing 
the resemblance between the explosive property of the French and Austrian pyroxyles. 
We will not here describe all the attempts made by the Commission of 1846 to obviate 
the inconvenience arising from the too rapid combustion of pyroxylin, but will confine 
ourselves to those made for the same purpose by General Lenk. 
He first unsuccessfully tried compressed cartridges, then some which he called long, 
cartridges, formed of paper cylinders covered with gun-cotton yarn. With these, an 
Austrian 12-pounder charged with about 484 grammes of gun-cotton gave a velocity of 
427 metres. . . . 
But this speed, though the greatest attained by the experiments in question, is less 
than that obtained in France with a similar gun, and with a charge of 2 kilogrammes of 
ordinary powder, which was about 480 metres, and which the Commission of 1846 en¬ 
deavoured to attain by using 667 grammes of pyroxylin. 
Now, it has not been proved that Lenk’s cartridges would not injure pieces of ordnance, 
were the quantity of pyroxylin increased so as to obtain the same speed as in France. 
The author of one of the Austrian reports recognizes the fact that the results obtained 
are unsatisfactory, and that the mechanical means employed to prevent the development 
of the injurious properties of the pyroxylin neutralize part of its propelling power ; and 
arrives at the conclusion that the problem will be resolved only when firearms are made 
in which the injurious effect may be disregarded. This is also our opinion ; but how to 
overcome the objection of the spontaneous explosions, which to us is the first considera¬ 
tion? . 
The result of our researches is that though the composition, method of proauction, and 
