He saw a cab pull up on the other side; it discharged two passengers, who argued about who should have the privilege of paying the driver.
The cab pulled away; and the man watching it from the sedan never detected the blotch of blackness that flitted into the back seat just before the driver closed the door.
The taxi driver did not see it either. In fact, he was stupefied, a short while later, when a head appeared from the interior of the cab, and he was given an address by a passenger whose presence he had not suspected.
The cabman was somewhat in a quandary about how to regulate the meter; for he did not know when his passenger had arrived. But the man in back settled that matter, by handing him more than sufficient payment.
The sedan pulled away not long after the cab. It wended its way uptown, again, and stopped for nearly an hour in front of Prince Zuvor’s house. Then one of the occupants alighted, and walked along the street, while the other drove away.
The man who was on foot was an observant fellow; but he did not see the peculiar shadow that had suddenly detached itself from the house that he had been watching.
He stopped at a restaurant, and his companion joined him. The other had put the car in a garage. The two men sat and talked.
They scarcely observed a quiet, black-clad individual, who sat in a corner, eating alone.
Leaving the restaurant, the men walked along a street, and their shadows moved with them, by the curb.
Had they looked behind, they would have seen a third shadow, not far in the rear; a strange, uncanny shadow — one that apparently had no right to exist; for no human being was visible beside it.
The men reached a house, and entered. When they had gone in, the shadow that had kept pace with them suddenly disappeared. It melted into the shadow of the house, and its presence was no longer evident.
Those who followed had, in turn, been followed.
They had been traced by The Shadow!
CHAPTER XIX
THE GHOSTS OF DEATH ISLAND
THE first three days at Death Island had been uneventful ones for Harry Vincent. His strange introduction to the men who lived there had been followed by very prosaic reality.
He was lodged in an upstairs room on the second floor; and it appeared to be a typical room of the house.
The downstairs portion of the building was quite ordinary — with the exception of Professor Whitburn’s study, which was simply the working room of a very eccentric man.
Harry had quickly become accustomed to the routine of the place. He had met the other member of the group — Marsh — and had found him to be quite as unusual as Crawford and Stokes. In fact, Marsh was more unusual.
He was a pale, gawky fellow, more than six feet tall, who walked with a pronounced stoop, as though accustomed to ceilings that were too low for him.
Each man seemed to have certain duties to perform, which were his own particular business. There must be some tasks that they shared in common, for occasionally Harry saw two together; but usually they were alone.
Crawford handled the cooking, and the men helped themselves to the food. Professor Whitburn seemed to eat very little, and Crawford attended to his meager wants.
Harry’s work proved to be the accumulation of knowledge. Professor Whitburn had supplied him with numerous textbooks on engineering, and had marked certain passages which he proposed that Harry should read.
The motor boat was seldom used. Sometimes Crawford operated it; sometimes Stokes. One or the other went to get supplies or mail. The former appeared to be Crawford’s job; the latter was the duty of Stokes.
Wandering about the island, between his studies, Harry found it to be of small acreage, and thickly wooded; yet precisely the sort of island one might expect to find in a Connecticut lake.
There was no chance to obtain the radio equipment that he had in his car. Harry decided to wait, and save the radio as a later advantage, if he should happen to need it.
In the daytime, Death Island was quiet and pleasant; but, strangely enough, it was avoided by the loud-crying birds that seemed to be plentiful on the main land. Outside of the men who had accepted this isle as their residence, Professor Whitburn’s cat seemed to be the only living thing on Death Island.
This fact was hardly significant; yet it fitted in with the ominous name of the place.
Harry had noticed that the house was equipped with a towerlike third floor. There was a bolted door on the second story that appeared to be an entrance to the tower.
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.
There were three men who could be dangerous if they chose. Yet they all seemed governed by the dynamic mind of Professor Whitburn. They discussed nothing among themselves. Each went to headquarters for instructions.
Now another day was drawing to its close. Harry sat in the plainly furnished living room, and let his mind wander from the books before him. It was after six o’clock. Dinner would soon be ready.
Marsh entered. He did not speak to Harry. He went across the room, and pushed aside a sliding panel in the wall. He revealed a radio set — something which Harry had not known was here.
Marsh adjusted the dials, and listened for a few minutes to a New England station. Then, as though he had refreshed his mind sufficiently with entertainment, he turned off the switch, and closed the panel.
Dinner was ready shortly after that. During the meal, Marsh made a few remarks, addressed chiefly to Stokes, who grunted brief replies. When the men had finished eating, it was dark outside. The night was cloudy, and a wind was gathering.
Harry went back to his books. He concentrated a while; then his mind turned from his work, and he found it very boring, alone in the living room, which was dim, except in the one corner where he sat. He noted that it was nearly nine o’clock; and he sensed an immediate opportunity.
Here was his chance to tune in on Station WNX. Now that he knew of the existence of the radio set, he might receive a message.
THE idea was a good one. Harry opened the sliding panel, and obtained WNX just as a program was ending. The theme song of the nine-o’clock program came softly over the air. Harry kept the sound as low as possible.