By the time he reached the castle, the night was dark indeed. He approached it by the path along the burn, and felt his way cautiously up the steep zigzags of the hill, and past the servants' quarters, where a dog barked and gave him an uneasy minute till he found that it was tied up, and that the noise which issued from a brilliantly lighted window—which he guessed to be the servants' hall—did not cease or diminish on account of it.
There were no other lights to be seen, and he edged his way round to the front of the house, which loomed very black and mysterious against the liquid darkness of the moonless sky. A little wind had risen, and the sound of a million leaves rustling gently on the trees of the woods around was added to the distant murmur of the burn, so that the night seemed full of noises, and every bush alive and watching.
Keeping on the grass, and with every precaution of silence, Gimblet crept along till he thought he was outside the drawing-room.
It did not take him long to find the window he had left unlatched that afternoon, but it was an anxious moment till he made sure that no one had noticed it and that it was yet unfastened. If a careful housemaid had discovered it and shut it, he would have to begin housebreaking in earnest. Luckily it opened easily at his touch, and he lost no time in climbing in, though it was rather a tight squeeze through the narrow imitation Gothic mullions, and he was thankful there were no bars as in the library.
He had more than once during his career found himself obliged to enter other people's houses in this unceremonious, not to say burglarious fashion. But it was always an exciting experience; and his heart beat a trifle faster than usual as he stood motionless by the window, straining his ears for the sound of any movement on the part of the household. Nothing stirred, however, and by the help of an occasional gleam from his pocket electric torch Gimblet made his way to the door, and through the deserted house to the distant passage leading to the old tower. Once inside the library he breathed more freely, and when, after holding his breath for some minutes, he had made certain that the absolute silence of the place continued unbroken by any suspicion of noise, he felt safer still. His first act was to draw the curtains, and to fasten them together in the middle with a large safety-pin he had brought for the purpose. Then, secure from observation, he switched on his torch, placed it on the table with its back to the window, and set about what he had come to do.
As he had not failed to observe, earlier in the day, the book-lined walls of the library were broken, opposite the window, by a panelled alcove where a small table stood, beyond which, against the wall, was a very large and tall grandfather's clock of black and gold lacquer, in imitation of the Chinese designs so popular in the eighteenth century.
Among Lord Ashiel's last words, "The clock" had been uttered immediately after the detective's own name. No doubt they formed part of a message he wished to convey; and, though they might refer to any clock in or out of the house, it seemed to Gimblet worth while to begin his investigations with the one nearest at hand, and he turned his attention to it without loss of time.
Gimblet was a connoisseur of the antique, and a few minutes' examination proved to him that this was a genuine old clock, untouched by the restorer's hand, and in an excellent state of preservation. The works appeared all right as far as he could make out, but through the narrow half-moon of glass, so often inserted in the cases of old clocks for the purpose of displaying the pendulum, that article was not to be seen, and he found that it was missing from inside the case, as were also the weights, so that it was impossible to set it going. There was one odd thing about it, which the detective had already remarked: it was firmly fixed to the wall by large screws, and he thought that there must be some opening through the back into a receptacle contrived in the panelling behind it. The case was so large that he was able to get inside it, and examine inch by inch the wood of the interior, which was lacquered a plain black.
But his most careful tappings and testings could discover no hidden spring, nor, even by the help of the electric torch—which he passed all over the smooth surfaces of the walls—could he discern the slightest join or crack. Could there be a hiding place up among the wheels of the motionless works? His utmost endeavours could discover none. The clock was fully eight feet high, but with the help of a stool, which he put inside on the floor of the case, he was able to explore even the topmost corners. All to no purpose.
Presently he abandoned that field of research, replaced the stool whence he had taken it, and gave his attention to the surrounding walls. He examined each panel with the most painstaking care, but could find nothing. There was no sign of secret drawer or cupboard anywhere.