In the first decade of the century it had been generally supposed that the X ray, or cathode ray, had been developed and applied to the utmost extent of its capability.

It was used in surgery and in mechanical arts, and in many varieties of scientific operations, but no considerable advance in its line of application had been recognized for a quarter of a century.
But Roland Clewe had come to believe in the existence of a photic force, somewhat similar to the cathode ray, but of infinitely greater significance and importance to the searcher after physical truth.
Simply described, his discovery was a powerful ray produced by a new combination of electric lights, which would penetrate down into the earth, passing through all substances which it met in its way, and illuminating and disclosing everything through which it passed.
All matter likely to be found beneath the surface of the earth in that part of the country had been experimented upon by Clewe, and nothing had resisted the penetrating and illuminating influence of his ray--well called Artesian ray, for it was intended to bore into the bowels of the earth.

After making many minor trials of the force and powers of his light, Roland Clewe had undertaken the construction of a massive apparatus, by which he believed a ray could be generated which, little by little, perhaps foot by foot, would penetrate into the earth and light up everything between the farthest point it had attained and the lenses of his machine.

That is to say, he hoped to produce a long hole of light about three feet in diameter and as deep as it was possible to make it descend, in which he could see all the various strata and deposits of which the earth is composed.

How far he could send down this piercing cylinder of light he did not allow himself to consider.