Peering into the shaft we could make out the floor of a tunnel some thirty feet down.

To judge by its effects, this shell had been of a different type from any others whose work we had witnessed.

Apparently it had been devised to excavate holes rather than to explode, and when we asked questions about it we speedily ascertained that our guide did not care to discuss the gun which had inflicted this particular bit of damage.
"It is not permitted to speak of this matter," he said in explanation of his attitude.

"It is a military secret, this invention.

We call it a mine gun." Every man to his taste.