All this of course was not only perceived by his guardian medical attendant, but blessed with his strong approval, for nothing counteracts the taste for liquor so effectually as another hobby. But what Thomas Sylvester devoutly prayed the doctor did not see was his patient slipping out of his window in the small hours of the morning, and from the roof of an out-house just below, examining the shore through a night glass. In February and March weather this was far too uncomfortable to last long or to be repeated every night, and the shore was too far away to make it very effective. Still, he did think he noticed a glimmer once or twice, and each time his antiquarian expedition next day included certain artless enquiries which might have thrown some light on the matter had the answers been satisfactory. As a matter of fact, however, they never were, and the extraordinary appearance of interest with which the effusive gentleman listened to useless information reflected more credit on his resolution than any one will ever realise. I may add that the professional watchers in the island were not of course in the secret of Mr. Hobhouse's identity, and therefore could not report to him directly anything they might see or suspect. But if they did see or suspect anything he would very quickly be informed through another source. However Commander Whiteclett based no great hopes on the possibility of catching our wily enemy out by means of a palpable man in uniform, and Mr. H. had been instructed to act exactly as though he were alone on the job. One of his earliest expeditions was made to the site of a prehistoric building in the near vicinity of the Scollays' farm. At least there was a grassy knoll visible which Mr. H.'s expert eye at once pronounced to be worthy of very careful inspection, and in order to confirm his theories he decided to visit the farm to make enquiry as to any possible traditions regarding it. He passed round the knoll with this purpose, to discover that he was no longer meditating alone. A familiar figure confronted him, with dark staring eyes, gaping mouth, and stubby beard; my old friend Jock. For a moment there returned that feeling of stage fright. Next to the Rendalls, the Scollay household, and particularly Jock, had seen and conversed most often with the mysterious Merton. Jock was only an idiot, but where reason is lacking instinct is apt to be strong, and instinct might distinguish an old acquaintance through all my disguise. Anyhow, rightly or wrongly, I felt that this was another delicate moment. "Good-day, my good fellow. Good-day to you!" said the friendly Mr. Hobhouse. "A little better weather to-day!" The surprise of the affable gentleman at getting only a grunt in reply, his air of gradual comprehension, and then of friendly sympathy, were acted for all they were worth. And to my vast relief, Jock showed no glimmer of recognition of the young man with the revolver.