The Adventure of the Engineer's Thumb

"The Adventure of the Engineer's Thumb," one of the 56 short Sherlock Holmes stories written by Sir Arthur Conan Doyle, is the ninth of the twelve stories collected in The Adventures of Sherlock Holmes. The story was first published in The Strand Magazine in March 1892. Within the narrative of the story, Dr. Watson notes that this is one of only two cases which he personally brought to the attention of Sherlock Holmes.

Synopsis
In the summer of 1889, a young Londoner and consultant hydraulic engineer, Victor Hatherley, recounts the strange events that occurred to him the night before, initially to Dr. Watson and later to Sherlock Holmes.

Hatherley was visited by a man who identified himself as Colonel Lysander Stark and offered a confidential 50 guinea (£, ) commission to examine a hydraulic press at a country house in Eyford, Berkshire that Stark claimed was used to compress fuller's earth into bricks. Despite his misgivings and theorising that Stark was lying about the machine's true purpose, Hatherley felt compelled to accept the offer, as his business was newly established and he had little work.

Upon arriving at an appointed train station, Hatherley was picked up by a carriage with frosted glass windows and traveled what he believed was a considerable distance to the house. Distracted by his desire to be paid, Hatherley ignored a woman's warnings to escape before he examined the press and made recommendations on how to fix it. Upon further investigation however, he discovered the floor was covered in a "crust of metallic deposit." Realising his theory was right, he confronted Stark, who then tried to kill him with the press. After the woman helped Hatherley escape, a murderous Stark pursued him with a cleaver, forcing Hatherley to jump from a second-storey window, losing his thumb to Stark in the process. Surviving the fall and landing within some rose bushes, Hatherley passed out and later awoke by a hedge near the train station.

Once Hatherley finishes his story, Holmes deduces that Stark and his allies are counterfeiters, their machine was used to create false half crowns, the carriage driver drove "six [miles] out and six back" to disguise the house's location, and Stark's group is responsible for the disappearance of another consultant hydraulic engineer a year prior. Holmes, Watson, and the police travel to the house Hatherley described, only to find it had been set ablaze after Hatherley's lamp was crushed inside the press. Their operation ruined, the counterfeiters fled in the direction of Reading, Berkshire with several "bulky boxes."

Publication history
"The Adventure of the Engineer's Thumb" was first published in the UK in The Strand Magazine in March 1892, and in the United States in the US edition of the Strand in April 1892. The story was published with eight illustrations by Sidney Paget in The Strand Magazine. It was included in the short story collection The Adventures of Sherlock Holmes, which was published in October 1892.

Film and television
A silent short film adaptation was released in 1923 as part of the Stoll film series starring Eille Norwood as Holmes.

The story was adapted for an episode of the 1954–1955 television series Sherlock Holmes starring Ronald Howard as Holmes and Howard Marion Crawford as Watson. The episode was titled "The Case of the Shoeless Engineer" and the story was altered so that Hatherley loses a shoe rather than his thumb, and Stark and his co-conspirator are captured by Lestrade with the assistance of Holmes.

The story was additionally adapted for the TMS Entertainment anime series Sherlock Hound, specifically in the episode "A Small Client" (1984). The general gist of the story was retained, but contained several differences, namely Professor Moriarty being in charge of the counterfeiting instead of Stark (who is not present in the episode at all), and the case being brought to Hound's attention through the engineer's young daughter instead of the engineer himself, who is being kept prisoner for the majority of the episode.

The story was also adapted in the 1986 Soviet TV movie The Adventures of Sherlock Holmes and Dr. Watson – The Twentieth Century Approaches. There, the criminal (Col. Stark) is Eduardo Lucas from "The Adventure of the Second Stain", and the gang's work is economic sabotage by the German Empire. Upon hearing the details, Mycroft Holmes decides to balance the damage by producing an equal amount of counterfeit German currency.

An episode of the animated television series Sherlock Holmes in the 22nd Century was based on the story. The episode, also titled "The Adventure of the Engineer's Thumb", aired in 2001.

Radio
Edith Meiser adapted the story as an episode of the radio series The Adventures of Sherlock Holmes, which aired on 17 December 1931, starring Richard Gordon as Sherlock Holmes and Leigh Lovell as Dr. Watson. Another episode adapted from the story aired on 24 February 1935 (with Louis Hector as Holmes and Lovell as Watson).

Edith Meiser also adapted the story as an episode of the radio series The New Adventures of Sherlock Holmes, with Basil Rathbone as Holmes and Nigel Bruce as Watson, that aired on 20 October 1940. Other episodes in the same series that were adapted from the story aired in June 1943 and January 1948 (with John Stanley as Holmes and Alfred Shirley as Watson).

A radio adaptation aired on the BBC Light Programme in 1960, as part of the 1952–1969 radio series starring Carleton Hobbs as Holmes and Norman Shelley as Watson. It was adapted by Michael Hardwick.

"The Engineer's Thumb" was dramatized by Peter Mackie for BBC Radio 4 in 1991, as part of the 1989–1998 radio series starring Clive Merrison as Holmes and Michael Williams as Watson. It featured John Moffatt as Lysander Stark.

The story was adapted as an episode of the radio series The Classic Adventures of Sherlock Holmes, starring John Patrick Lowrie as Holmes and Lawrence Albert as Watson. The episode aired in 2015.