The pickaxes hardly made any impression on the rock, but its disaggregation was effected with really remarkable facility by means of the fulgurator.
A few grains of this explosive shattered the rocky mass and reduced it to almost impalpable powder that one's breath could disperse as easily as vapor.

The explosion produced an excavation measuring fully a cubic yard.

It was accompanied by a sharp detonation that may be compared to the report of a cannon.
The first charge used, although a very small one, a mere pinch, blew the men in every direction, and two of them were seriously injured.
Engineer Serko himself was projected several yards, and sustained some rather severe contusions.
Here is how this substance, whose bursting force surpasses anything hitherto conceived, is employed.
A small hole about an inch and a half in length is pierced obliquely in the rock.

A few grains of the explosive are then inserted, but no wad is used.
Then Thomas Roch steps forward.

In his hand is a little glass phial containing a bluish, oily liquid that congeals almost as soon as it comes in contact with the air.