What is the name of the engineer in 'The Adventure of the Engineer's Thumb'?

The engineer in “The Adventure of the Engineer’s Thumb” is Victor Hatherley.

Hatherley is a young London consultant hydraulic engineer whose newly established practice has little work. He accepts a confidential commission from Colonel Lysander Stark, who asks him to inspect a powerful hydraulic press at a country house near Eyford in Berkshire. Stark claims that the machine is used to compress fuller’s earth into bricks.

Hatherley quickly notices that the press is far too powerful for that purpose and suspects that its real function involves metal. When he examines it more closely, Stark and his accomplices try to kill him. Hatherley escapes through a window, but Stark cuts off his thumb with a cleaver during the pursuit.

Holmes later deduces that the machine was being used by counterfeiters to manufacture false half-crowns. Readers sometimes confuse Hatherley with other engineers or clients in the Holmes stories, but Victor Hatherley is the named narrator and central witness here. The story was first published in 1892 and is one of only two cases Watson says he personally brought to Holmes.