explosives, the following ranges:

Meters.
Blasting powder 2.6
No. 1 dynamite 31.4
Forcite of 75 per cent. N.G. 43.6
Blasting gelatine 45.0

Roux and Sarran obtained by experiments in bursting small bomb shells
the following comparative strengths of ranges:

Powder 1.0
Gun-cotton 6.5
Nitro-glycerine 10.0

In actual blasting work the results vary altogether with the nature of
the material encountered, and with the result that is desired to be
accomplished, viz., throwing out, shattering, or mere displacement.

Chalon gives for quarrying:

Powder 1
Dynamite No. 2, containing 50 per cent. nitro-glycerine 3

For open blasting:

Dynamite No. 3, containing 30 per cent. N.G. 1.0
Dynamite No. 1, containing 75 per cent. N.G. 2.5
Blasting gelatine 3.5

For tunneling:

Dynamite No. 3, containing 30 per cent. N.G. 1
Dynamite No. 1, containing 75 per cent. N.G. 3
Explosive gelatine 19

Finally Berthelot's theoretical calculations give a specific pressure
of--

Powder 1
Dynamite 13
Gun-cotton 14
Nitro-glycerine 16
Blasting gelatine 17

It will be observed that the practical results vary largely from the
theoretical values, but they seem to indicate that gun-cotton and No.
1 dynamite are very nearly equal to each other, and that in the
nitro-glycerine compounds, except where gun-cotton is added, the force
appears to be nearly in proportion to the nitro-glycerine contained.
From the foregoing it seems fair to estimate roughly the values of
bursting charges of shells as follows:

Powder 1
Gun-cotton and dynamite 6 to 10
Nitro-glycerine 13 to 15
Blasting gelatine 15 to 17

Attention has been turned in Europe for more than thirty years toward
firing high explosives in shells; but it is only within very late
years that results have been reached which are claimed as
satisfactory, and it is exceedingly difficult to obtain reliable
accounts even of these. Dynamite was fired in Sweden in 1867 in small
quantities, and a few years later it was fired in France. But two
difficulties soon presented themselves. If t