He threw it open, and as he did so there was a low, harsh murmur, growing steadily into a loud roar as a train dashed past us in the darkness. Holmes swept his light along the window-sill. It was thickly coated with soot from the passing engines, but the black surface was blurred and rubbed in places.
“You can see where they rested the body. Halloa, Watson! what is this? There can be no doubt that it is a blood mark.” He was pointing to faint discolorations along the woodwork of the window. “Here it is on the stone of the stair also. The demonstration is complete. Let us stay here until a train stops.”
We had not long to wait. The very next train roared from the tunnel as before, but slowed in the open, and then, with a creaking of brakes, pulled up immediately beneath us. It was not four feet from the window-ledge to the roof of the carriages. Holmes softly closed the window.
“So far we are justified,” said he. “What do you think of it, Watson?’
“A masterpiece. You have never risen to a greater height.”
“I cannot agree with you there. From the moment that I conceived the idea of the body being upon the roof, which surely was not a very abstruse one, all the rest was inevitable. If it were not for the grave interests involved the
