“How long is this to last?” asked the inspector finally. “And what is it we are watching for?”
“I have no more notion than you how long it is to last,” Holmes answered with some asperity. “If criminals would always schedule their movements like railway trains, it would certainly be more convenient for all of us. As to what it is we— Well, that’s what we are watching for!”
As he spoke the bright, yellow light in the study was obscured by somebody passing to and fro before it. The laurels among which we lay were immediately opposite the window and not more than a hundred feet from it. Presently it was thrown open with a whining of hinges, and we could dimly see the dark outline of a man’s head and shoulders looking out into the gloom. For some minutes he peered forth in furtive, stealthy fashion, as one who wishes to be assured that he is unobserved. Then he leaned forward, and in the intense silence we were aware of the soft lapping of agitated water. He seemed to be stirring up the moat with something which he held in his hand. Then suddenly he hauled something in as a fisherman lands a fish—some large, round object which obscured the light as it was dragged through the open casement.
“Now!” cried Holmes. “Now!”
We were all upon our feet, staggering after him with our stiffened limbs, while he ran swiftly across the bridge and rang violently at the bell. There was the rasping of bolts from the other side, and the amazed Ames stood in the entrance. Holmes brushed him aside without a word and, followed by all of us, rushed into the room which had been occupied by the man whom we had been watching.