Stories / The Adventures of Sherlock Holmes · 1892
The Adventure of the Engineer's Thumb
A hydraulic engineer loses a thumb and nearly his life in a press used for coining; carriage distances betray the house that burned.
✅ Public domain — read, share, and adapt freely.
⚠️ Spoilers below. The analysis discusses the solution, including who did it and how it's found out.
Summary & analysis
Watson brings Holmes a patient and a case in one: Victor Hatherley, hydraulic engineer, thumb severed by a cleaver, hired at midnight for fifty guineas to inspect a fuller's-earth press in secrecy — a fee too large for the work by exactly the amount of its danger.
Hatherley's own narrative is the middle: the muffled drive of unknowable length, the press-room's metallic crust, his diagnosis of the machine — and the moment the ceiling begins to descend on him after he shows too much curiosity. The escape through a window costs him the thumb.
Holmes resolves the geography with a compass drawn on a map: a horse driven an hour out and an hour back means home is near the station, not far — six directions collapse to one, but the coiners fire their own house and vanish. The counterfeiters escape; the reasoning does not.
Deeper reading
A victim's tale
Unusually, this story is told largely as the client\'s own narrative of terror — a hydraulic engineer lured to a lonely house, nearly crushed in a coining press, escaping with the loss of his thumb. Holmes has little to deduce and less to prevent; the criminals escape entirely. It is one of the canon\'s few cases the detective effectively loses, redeemed by the vividness of the ordeal.
Distance as the only clue
The single piece of real detection is geometric: a horse driven an hour out and an hour back cannot be far from the station, so six possible directions collapse to one. It is a neat demonstration of turning a measurement — here, duration — into a location, even when everything else about the case ends in smoke.
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Techniques on display
Deduction & inference
Chaining evidence into conclusions on a living board.
In this story: Fuller's earth is the cover story that cannot pay the wages offered; Holmes prices the lie — secrecy premiums reveal what the machine really presses.
Chronology
Laying events end to end until contradictions die.
In this story: Twelve miles out plus twelve back at a fresh horse's pace, but only Eyford scale — the journey was circular, and duration measured deception rather than distance.
Practise what this story preaches: every technique above links to a tool or game built on the same method. The best way to learn the canon is to reason along with it.