The Adventure of the Engineer's Thumb

An engineer, Victor Hatherley, attends Dr Watson's surgery after his thumb is chopped off, and recounts his tale to Watson and Holmes. Hatherley had been hired for 50 guineas to repair a machine he was told compressed Fuller's earth into bricks. Hatherley was told to keep the job confidential, and was transported to the job in a carriage with frosted glass, to keep the location secret. However, when they arrive, the house is on fire, and the criminals have escaped.