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.
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