application, and but little light was thrown upon the results which
might be anticipated from a large mine at a greater distance, whose
radius of explosive effect would embrace a larger portion of the ship,
and especially if the ship were nearly over the torpedo. The local
effect of a detonation is different from the transmitted shock.
Experiments in England have shown that 500 pounds of gun-cotton at
forty feet below any ship will sink her, and at a horizontal distance
of 100 feet, damage to the interior pipes and machinery is to be
expected.

The fact that the high explosives are so much heavier than gunpowder
has an important bearing on the size of the containing case. Their sp.
gr. is as follows:

Nitro-glycerine............................ 1.6
Blasting gelatine.......................... 1.45
Forcite " .......................... 1.51
Dynamite No. 1............................. 1.6
Wet gun-cotton............................. 1.32
Dry " ............................. 1.06
Gunpowder.................................. 0.9

Their relative efficiency under water per cubic foot, according to
Bucknill, is as follows:

Blasting gelatine.......................... 1.38
Forcite " .......................... 1.27
Dynamite No. 1............................. 1.00
Dry gun-cotton............................. 0.66
Wet " ............................. 0.66