In making experiments to determine the relative strength of the
different explosives under water, very curious and puzzling results
have been obtained. Nitro-glycerine being the simplest and most
complete in its chemical decomposition, and apparently the most
powerful in air, it was natural to suppose that it would be the same
in submarine work, but it was found by Gen. Abbot, at Willets Point,
after repeated experiments, as shown in his report of 1881, that it
was not so powerful in its effect by twenty per cent. as dynamite No.
1, although the dynamite contained twenty-five per cent. of an
absolutely inert substance. His idea was that it was too quick in its
action, and, since water is slightly compressible, a minute fraction
of time is required in the development of the full force of the
explosive. Gen. Abbot's results for intensity of action per unit of
weight of the most important substances is as follows:

Blasting gelatine........................... 142
Forcite " ........................... 133
Dynamite No. 1.............................. 100
Gun-cotton, wet............................. 87
Nitro-glycerine............................. 81
Gunpowder.............................. 20 to 50

Col. Bucknill, of the Royal Engineers, in his publication of 1888,
gives the following:

Blasting gelatine........................... 142
Forcite " ........................... 133
Dynamite No. 1.............................. 100
Gun-cotton, dry............................. 100