In a way he was the assistant of the man who worked the Burly.

It was his duty to replace the drills in the Burly, putting in longer ones as the hole got deeper and deeper.

From time to time he rapped the drill with a pole-pick when it stuck fast or fitchered.
Once it even occurred to him that there was a resemblance between his present work and the profession he had been forced to abandon.

In the Burly drill he saw a queer counterpart of his old-time dental engine; and what were the drills and chucks but enormous hoe excavators, hard bits, and burrs?
It was the same work he had so often performed in his "Parlors," only magnified, made monstrous, distorted, and grotesqued, the caricature of dentistry.
He passed his nights thus in the midst of the play of crude and simple forces--the powerful attacks of the Burly drills; the great exertions of bared, bent backs overlaid with muscle; the brusque, resistless expansion of dynamite; and the silent, vast, Titanic force, mysterious and slow, that cracked the timbers supporting the roof of the tunnel, and that gradually flattened the lagging till it was thin as paper.
The life pleased the dentist beyond words.

The still, colossal mountains took him back again like a returning prodigal, and vaguely, without knowing why, he yielded to their influence--their immensity, their enormous power, crude and blind, reflecting themselves in his own nature, huge, strong, brutal in its simplicity.