In the meantime the crowd had increased from a few hundred to thousands. Police appeared. The corridors were cleared of all but a few. Among these were Hallowell and Jack Warford; the former as a reporter, the latter as the reporter's companion. Doctor Knox and Professor Eldridge arrived shortly. After a time Darrow reappeared, sauntering quite calmly from the pall of darkness, as though emerging from behind a velvet curtain.

CHAPTER XII

THE UNKNOWN

It will now become necessary to glance in passing at the personal characteristics of Professor Eldridge. This man was in about his fortieth year, tall, spare, keenly intellectual in countenance, cold, possessed of an absolute reliance on the powers of science, beyond which his mental processes did not stray. His manner was distinguished by a stiff unbending formality; his expression by a glacial coldness of steel-gray eyes and a straight-line compression of thin lips; his dress by a precise and unvarying formalism, and his speech by a curious polysyllabic stiffness.

This latter idiosyncrasy would, in another, have seemed either priggish or facetiously intended. With Professor Eldridge it was merely a natural method of speech. Thus, arriving once at the stroke of the dinner hour, he replied to compliments on his punctuality by remarking:

"I have always considered punctuality a virtue when one is invited to partake of gratuitous nourishment."

Withal, his scientific attainments were not only undoubted, but so considerable as to have won for him against many odds the reputation of a great scientist. His specialty, if such it might be called, was scientific diagnosis. The exactness of scientific laws was so admirably duplicated by the exactitudes of his mind that he seemed able, by a bloodless and mechanical sympathy, to penetrate to the most obscure causes of the strangest events. It might be added that practically his only social ties were those with the Warfords, and that the only woman with whom he ever entered into conversation was Helen.

At sight of him Percy Darrow's lounging gait became accentuated to exaggeration.

"Hello, Prof!" he drawled. "On the job, I see. Good morning, Doctor," he greeted Knox. "What do you make of it?"

"I make of it that the Atlas Building will shortly be without tenants," replied the doctor; "me, for one."