obstruct

It is true that a shutter had half closed outside and obstructed the view, but none the less it was certainly at the window that Holmes was fixing his concentrated attention.

Some few minutes had elapsed, and the stranger began to show manifest signs of impatience, when a slight noise was heard outside the aperture in the roof, and almost immediately a dark shadow seemed to obstruct the flood of light that had entered it, and the figure of a man was clearly seen gazing with eager scrutiny on the immense space beneath him; then, as his eye caught sight of him in the mantle, he grasped a floating mass of thickly matted boughs, and glided down by their help to within three or four feet of the ground, and then leaped lightly on his feet.