It seemed to be the only part of the house that held a semblance of mystery — unless the basement, which was reached through a door in the kitchen, might hold some unknown secret.

Harry’s observations were confined chiefly to the men with whom he was associated.

He had already formed a definite impression of Professor Whitburn. He had talked with the old man several times, and classed him as a genius who preferred to work undisturbed.

But the other three were difficult to analyze. Harry was with them during meals, and he did his best to formulate opinions regarding them.

None of them impressed Harry. They all seemed undesirable: Marsh, less than the others. The stoop-shouldered man had an expressionless face, but he did not appear to be a troublemaker.

Stokes, whose twisted features made one unconsciously prejudiced against him, seemed to possess a native cleverness. At the same time, he had traits of agreeability that showed themselves on rare occasions.

Crawford, with his heavy, unkempt beard, was more repulsive in daylight than at night; and Harry made no effort whatever to become friendly with him.

These men reminded Harry of volcanoes — hard, unyielding and rugged. He wondered what they would be like if aroused to action.

He believed that any one of them could burst forth with a dangerous eruption. In fact, he realized that he had classed them as he would enemies. Marsh — a man who would fight, but who could be outwitted. Stokes — a dangerous foe, who could combine power with cleverness. Crawford — a fellow who could plot, battle, and use any means to gain his ends.

These mental observations had convinced Harry that the warning of the girl should not be forgotten. Danger lay here on Death Island.