Read it through once

Whilst he was speaking we were startled by a knock at the hall door, the double postman’s knock of the telegraph boy. We all moved out to the hall with one impulse, and Van Helsing, holding up his hand to us to keep silence, stepped to the door and opened it. The boy handed in a despatch. The Professor closed the door again, and, after looking at the direction, opened it and read aloud.