|The 1899 flashlight was a fiber tube with brass end caps and bulls-eye glass lens at one end.|
There is a trivial but interesting example in the fiction of Robert Barr. He was a friend of Conan Doyle in spite of the fact that he once wrote two parodies of Sherlock Holmes. Look up Sherlaw Kombs on Google.
In the passage below Barr feels it necessary to describe the workings of an electric torch so one assumes that most of his readers would be unfamiliar with such new-fangled gadgets.
It was perhaps half-past ten or eleven o'clock when I began my investigations. I had taken the precaution to provide myself with half a dozen so-called electric torches before I left London. These give illumination for twenty or thirty hours steadily, and much longer if the flash is used only now and then.
The torch is a thick tube, perhaps a foot and a half long, with a bull's-eye of glass at one end. By pressing a spring the electric rays project like the illumination of an engine's headlight. A release of the spring causes instant darkness. I have found this invention useful in that it concentrates the light on any particular spot desired, leaving all the surroundings in gloom, so that the mind is not distracted, even unconsciously, by the eye beholding more than is necessary at the moment. One pours a white light over any particular substance as water is poured from the nozzle of a hose.
The invention of the dry cell and miniature incandescent electric light bulbs made the first battery-powered flashlights possible around 1899.