548 MM. Pclouzc and Maurcy on the New Methods 



few weeks in a glass vessel (that is, in contact with sides which 

 have alkaline tendencies), gives an acid reaction. 



In darkness even this acidification is finally infallibly pro- 

 duced ; and Ave have seen specimens of gun-cotton which, after 

 being passed through alkaline solutions, and then kept in closed 

 boxes for several years, finished by corroding the paper which 

 enclosed them. 



Hence in gun-cotton submitted to the action of air and light, 

 or even kept in the dark, there is a commencement of alteration. 

 This alteration, very feeble at the beginning, may last several 

 years without increasing or presenting any inconvenience; but 

 suddenly, and without perceptible cause, it may develope and 

 cause an increase of temperature which produces a detonation. 

 When gun-cotton is seen to alter and become quite soluble by 

 a long exposure to diffused light, we cannot refuse to admit the 

 possibility of a decomposition accompanied by detonation ; for 

 detonation in the case of so unstable a substance must be very 

 near decomposition. 



It has been desired to attribute the cases of spontaneous de- 

 composition, especially in France, to the fact of the cotton not 

 having had a sufficiently long nor sufficiently energetic impreg- 

 nation with the sulphuric and nitric acids. 



We cannot admit this opinion, after having observed similar 

 effects of the action of temperatures of 100°, 80°, 60°, and 55° 

 on the Bouchet gun-cottons steeped for an hour, and on General 

 von Lenk's steeped for forty-eight hours. We are inclined, on 

 the contrary, to think that the gun-cotton prepared with large 

 quantities of very concentrated acids, and by prolonging the 

 duration of immersion, is more subject to spontaneous inflam- 

 mation. 



V. Comparison of the Lenk and Bouchet Gun-cottons as regards 

 their ballistic and bursting properties. 



We have now to make known the results of trials made with 

 the ballistic pendulum, to compare the tw r o kinds of gun-cotton 

 as regards their ballistic power. 



Twenty-five shots were fired with the Lenk cotton, fifteen 

 with the Bouchet cottons, with a charge of 3 grammes, and with 

 round balls weighing 25*50 grms. 



Taking for each set the mean velocity of the balls, then the 

 strongest, and then the weakest shot, w r e found — 



Gun-cottons. 



A 



( *i 



Lenk. Bouchet. 



m. m. 



Mean velocity . . 385-36 391-3.2 



Strongest shot . . 441*53 445'94 



Weakest shot . . 357*63 357*63 



