He was engaged in a dangerous business, and the consequences would be serious if the military authorities found him out; but this was not the worst he feared. They might be baffled; but Staffer had hinted that his employers were not satisfied, and it was a dangerous thing to disappoint them. Their rewards were liberal, but their servants must perform their task. Williamson shivered as he remembered what he had heard about the fate of one or two who had not succeeded in this.
Cowering behind the bank, while the cold wind whistled past, he carefully thought out the situation. He saw that he had to face one of two dangers. Either he had by some carelessness excited suspicion, and was being watched, or he was distrusted by his friends. In the latter case, flight to America was the only means of escape, because he knew enough to make his employers uneasy, and if they failed in one plan to put him out of the way, they would try another. He would certainly not be left free to save himself by telling what he knew. But if he had only the British authorities to fear, there was less cause for alarm. They could be thrown off the track; indeed, this must be done, for he dare not now abandon the work he had undertaken.
Williamson was getting very cold, and a searching drizzle had begun to fall; but he scarcely noticed it as he sat weighing the arguments for and against each supposition. Eventually, he decided that he must blame some incautiousness of his own, and he began to wonder whose suspicions he had aroused. Whitney had a motorcycle, and its tires would leave just such a mark as he had noticed; but this did not prove much, because the make was in common use. The American was shrewd and was a friend of Andrew's; but while both were antagonistic Williamson thought they opposed him only on Dick's account. Well, he had promised to leave Dick alone. That ought to satisfy them; and if he were very careful he would be able to elude any other enemies.
Feeling that his scare had been needless, he set off for Dumfries; although he had not yet reached an explanation of the motorcycle tracks.
CHAPTER XX
THE WHAMMEL BOAT
Thin fog drifted down the Firth when, with Whitney's help, Andrew pulled the dinghy up the bank and then stopped to look about. It was nine o'clock in the evening when they left the Rowan at anchor in the channel a hundred yards away, and he knew the tide was beginning to flow, which meant that he had an hour and a half in which to reach and return from the wreck. Everything was obscured to the east, but to the west the sky was clear, and a thin, bright moon shone in a patch of dusky blue. The sand felt harder than usual, for the night air was frosty, but the melancholy calling of the wild fowl told that the salt ooze in the gutters was still unfrozen. There was no other sound except the ripple of the current across the shoals.
"I suppose we'll let up for a bit if we see nobody to-night," Whitney suggested.
"Yes," said Andrew; "the tide's getting late."
Whitney nodded agreement. They had sailed from the burnfoot three days before, and after standing out to sea on the ebb, had returned to the outer end of the channel in the dark as soon as they could stem the slackening stream. Then, landing in the dinghy, they hung about the wreck until the advancing tide drove them back. They had done this for two nights, without seeing anything suspicious, and they could now abandon the search, because as the time of high-water approached six o'clock the tides did not run out far enough to enable anybody to reach the wreck from land.