He kept stepping back and forwards, doing a little dance, and eventually lay stomach down on the window-sill.
After that he got down to some important and mysterious work.
He covered the microscope with a bell glass.
Then he melted a piece of sealing-wax in the bluish flame of the Bun-sen burner, sealed the edge of the glass to the table and made a thumb print on the blobs of wax.
Finally he turned off the gas and went out, locking the laboratory door firmly behind him.
There was semi-darkness in the Institute corridors.
The Professor reached Pankrat's door and knocked for a long time to no effect.