To have an unconcealed entrance in the centre of that unprotected, open plain would be foreign to savage nature; while to imagine that such a tunnel as this, from which a vast amount of earth had been borne upon the backs of workmen, could extend below the full extent of that valley, was beyond conception.
Besides, the air was light and pure, as sweet to inhale as if it blew directly upon me from the open sky; itself proof positive that some opening could not be far distant.
Thus questioning, I groped slowly forward.

To one accustomed to living in the open there is something peculiarly oppressive in being cooped within the confines of such narrow entries, and being compelled to reflect upon the immense mass of rock and earth resting above, and prevented from crushing him down into everlasting silence only by insignificant props of wood, whose melancholy groaning in the darkness bore evidence of the vast weight they upheld.

There was nothing for me but to struggle onward, although I do not claim that it was without quaking heart, or many a start at odd noises echoing and re-echoing along that grim gallery.

It is comparatively easy to be courageous where the peril is of a nature to which we have long accustomed ourselves, but many a trained nerve gives way before little ventures amid the unknown.

I am told that soldiers coming to these colonies--veterans who had faced unflinchingly the flames of battle--will tremble and shrink like frightened girls at the slightest sign of a storm at sea; and there was once a famous war-chief of the Shawnees, who had fought fiercely with tomahawk and knife, yet who fell dead at the first crash of a field gun, although the piece was uncharged with ball.