Kettle

Then suddenly another sound became audible--a very gentle, soothing sound, like that of a small jet of steam escaping continually from a kettle.
(Adventure VIII, pg. 116)

Early kettles would have been made of iron and by the 19th century copper was a common material. In the mid 1900s alluminum and stainless steel kettles started to be manufactured.

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Bell pull

"Indeed, it seemed unnecessary to put so nice a bell-pull there. You will excuse me for a few minutes while I satisfy myself as to this floor."

(Adventure VIII, pg. 111)

The bell pull is one element of a complex interior mechanical network which typically in Victorian times involved a range of bell pulls in different rooms; moreover, these bell connections link to a central bank of bells in a room where servants would await commands.

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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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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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Gasogene

"With hardly a word spoken, but with a kindly eye, he waved me to an armchair, threw across his case of cigars, and indicated a spirit case and a gasogene in the corner." 
(Aventure I, A SCANDAL IN BOHEMIA pg. 3)

The gasogene is a late Victorian device used to carbonate water. It consists of two linked glass globes: the lower contained water or other drink to be made sparkling, the upper a mixture of tartaric acid and sodium bicarbonate that reacts to producing carbon dioxide. The produced gas pushes the liquid in the lower container up a tube and out of the device. The globes are surrounded by a wicker or wire protective mesh, as they have a tendency to explode.