John Henry "Professor" Pepper (17 June 1821 – 25 March 1900) was a British scientist and inventor who toured the English-speaking world with his scientific demonstrations. He entertained the public, royalty, and fellow scientists with a wide range of technological innovations. He is primarily remembered for developing the projection technique known as Pepper's ghost, building a large-scale version of the concept by Henry Dircks, which Pepper first publicly demonstrated during an 1862 Christmas Eve theatrical production of the Charles Dickens novella, The Haunted Man and the Ghost's Bargain, causing a sensation among those in attendance at the Regent Street theatre in London.
Pepper also oversaw the introduction of evening lectures at the Royal Polytechnic Institution (University of Westminster) and wrote several important science education books, one of which is regarded as a significant step towards the understanding of continental drift. While in Australia he tried unsuccessfully to make it rain using electrical conduction and large explosions.
