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

Powder1.0
Gun-cotton6.5
Nitro-glycerine10.0

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-glycerine3

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 gelatine3.5

For tunneling:

Dynamite No. 3, containing 30 per cent. N.G1
Dynamite No. 1, containing 75 per cent. N.G3
Explosive gelatine19

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