Here was something to go upon. Beyond doubt that gas had been used lately. Prout made a careful examination of the burners, sniffing and blowing at all of them. He found out one thing, only the burners in the hall and the bedroom where the murdered man had been found had been used for a long time. In a bedroom at the top of the house was a paraffin lamp with quite a new wick in it. With a stump of pencil Prout made a rapid calculation on the wall-paper..