234 British Artillery Matériel. 7 (April, 
The “ lithofra¢teur” differs from the nitroglycerine prepa- 
ration called ‘‘ dynamite”’ chiefly in containing a proportion 
of gunpowder constituents, viz., saltpetre, carbon, and sul- 
phur, mixed up with the other ingredients. From the sam- 
ples analysed it appears that this substance is crudely mixed, 
varies considerably in composition, and possesses no im- 
provement over dynamite. On the 2oth February, 1872, 
some exceedingly instructive trials of this compound were 
. made—by Professor Engels, of M. Kreb’s Cologne factory— 
at Mr. France’s Breidden Quarry, on the banks of the 
Severn, near Shrewsbury, before the W. O. Committee, 
when it appears to have most favourably endured the various 
tests, both chemical (to ascertain the fuming and explosive 
points) and mechanical (to test its safety under heavy blows 
and concussion) ; for instance, 5 lbs. of lithofracteur was 
exposed to a fierce flame and consumed without explosion. 
Cartridges of it were subjected to heavy blows, such as the 
fall of round shot upon them, when the plastic substance, 
although squeezed out, neither inflamed nor exploded. 
Similarly, it was ignited by a Bickford fuse in confinement, 
and inflamed without explosion. Naked cartridges fixed to 
buffers of a railway truck, allowed to run on an incline into 
violent collision with a stationary one, also failed to explode. 
On the other hand, the same substance when fired with a 
Bickford fuze and detonator, inthin zinc tubes 4} inches in 
diameter, either against stockades, in mines, or under water, 
exploded with inconceivable violence, the explosion in each 
case being perfect. It was stated that M. Rietschoten has 
conceived the bold proposition of cutting through a sand- 
bank of 1500 yards breadth, off Rotterdam, and so forming 
a deep channel through it by sinking tubing of that length 
charged with 10 tons of lithofra¢teur. For the defence of 
channels and entrances to our harbours nothing can be 
imagined more effective. The serious objection against it 
seems to be that, after keeping, the folds of thin paper of 
the cartridge become saturated with nitro-glycerine, absorbed 
from the material within, so that, according to Mr. Abel, in 
the application of it the hands of the operators must become 
soiled with that poisonous substance. No doubt this will 
be obviated. 
VI. For the better prevention of the erosion in the bores 
of rifled guns, various descriptions of wads have been pro- 
posed and experimented upon. The Royal Laboratory 
paper wads appear to be objectionable on account of pieces 
of them flying back in a state of ignition, which has, in the 
case of the Bolton’s wads, been already supposed to account 
