336 Recent Changes in British Artillery Materiel. [July, 



and the further report of the committee, which has 

 not yet been published, will be looked forward to with 

 interest. 



It fs to be hoped that the Government will not overlook 

 the valuable properties of dynamite for mining purposes, 

 not only on account of the additional work done by this 

 explosive in comparison with gun-cotton, but because the 

 produces of its combustion are less injurious to the health 

 of the miners who use it. 



On the other hand, from the following abstract of the 

 report on the lithofracteur, this substance is found too 

 defective to be introduced into the service at present. 



" The committee are of opinion that the substance pro- 

 vided for their experiments, under the name of lithofracteur, 

 has imperfectly fulfilled the absolutely necessary property 

 of retaining its proportion of nitro-glycerine, under circum- 

 stances which might be met with during ordinary transport 

 or storage. 



" Nitro-glycerine readily exuded from a proportion of the 

 cartridges of the lithofracteur subjected to trial, after a 

 comparatively short exposure to a temperature not exceed- 

 ing ioo° F. ; and although such a temperature may not 

 in an English climate be sustained for any length of time, 

 either during a railway journey or in a magazine, it must 

 be borne in mind that the nitro-glycerine once exuded may 

 not be re-absorbed, but that fresh exudation would probably 

 take place on each fresh application of heat, and that this 

 tendency to leakage might be facilitated by the shaking 

 inseparable from railway transit. 



" The capacity of lithofracteur for retaining nitro-glycerine 

 is very seriously interfered with by its becoming wetted. 

 The nitro-glycerine is readily expelled from a lithofracteur 

 cartridge immersed in water. The readiness with which 

 the lithofracteur parts with its nitro-glycerine, under the 

 influence of water, is dependent probably on the presence of 

 nitrate of soda as one of its constituents, a substance 

 exceedingly soluble in water ; and in the event of a box of 

 cartridges getting wet, water would replace part of the 

 nitro-glycerine, which would thus collect as a liquid form at 

 the bottom of the box. 



" The committee regret they cannot make a more favour- 

 able report upon a substance which may possess many 

 valuable properties for industrial purposes, but they regard 

 the tendency of some of the lithofracteur submitted to them 

 to part with its nitro-glycerine, under conditions that can 

 only be regarded as ordinary, as a defect too serious to be 



