Sewing machine

The sewing-machine, of the hand type, leaves a similar mark, but only on the left arm, and on the side of it farthest from the thumb, instead of being right across the broadest part, as this was.

(Adventure III, pg. 40)

The sewing machine that became popular in the 1850's both commercially and domestically.

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Image source
History

Typewriter

"Do you not find," he said, "that with your short sight it is a little trying to do so much typewriting?"
(Adventure III, pg. 35)

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- Description and history

Doorbell

Then I rang the bell, and, as I hoped, the assistant answered it. We have had some skirmishes, but we had  ever set eyes upon each other before.

(Adventure II, pg. 33)

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- Description and History

Handcuffs

"I beg that you will not touch me with your filthy hands," remarked our prisoner as the handcuffs clattered upon his wrists. "You may not be aware that I have royal blood in my veins. Have the goodness, also, when you address me always to say 'sir' and 'please.'"
(Adventure II, pg. 32)

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- History of handcuffs

Revolver

I placed my revolver, cocked, upon the top of the wooden case behind which I crouched. Holmes shot the slide across the front of his lantern and left us in pitch darkness--such an absolute darkness as I have never before experienced.

(Adventure II, pg 31)

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- Image source
- History of the revolver

Magnifying lens

Merryweather perched himself upon a crate, with a very injured expression upon his face, while Holmes fell upon his knees upon the floor and, with the lantern and a magnifying lens, began to examine [...]

(Adventure II, pg. 30)

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- Description and History

Lantern

This also was opened, and led down a flight of winding stone steps, which terminated at another formidable gate. Mr. Merryweather stopped to light a lantern, and then conducted us down a dark, [...]

(Adventure II, pg. 30)

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- Image Source
- History of lighting