Robert Davidson (18 April 1804 – 16 November 1894) was a Scottish inventor who built the first known electric four wheeled car in 1839 and in 1842 the first known electric locomotive. He was a lifelong resident of Aberdeen, northeast Scotland, where he was a prosperous chemist and dyer, amongst other ventures. Davidson was educated at Marischal College, where he studied second and third year classes from 1819-1821, including lectures from Professor Patrick Copland. He got this education in return for being a lab assistant.

In the 1820s, he set up in business close to the Aberdeen-Inverurie Canal, at first supplying yeast, before becoming involved in the manufacture and supply of chemicals.

He became interested in the new electrical technologies of the day. From 1837, he made small electric motors on his own principles.

Davidson staged an exhibition of electrical machinery at Aberdeen, Scotland, and in Edinburgh, where it was viewed on 12 February 1842 by the young James Clerk Maxwell.

Later he exhibited at the Egyptian Hall in Piccadilly in London, where he hoped to attract sponsorship for his work. Among the machines shown were his locomotive, an electrically driven lathe and printing press, and an electromagnet capable of lifting 2 tons.

Davidson made a model electric locomotive in 1837. His Galvani of 1842 was a four-wheeled machine, powered by zinc-acid batteries. It was tested on the Edinburgh-Glasgow line in September 1842 and, although found capable of carrying itself at 4 mph (6.4 km/h), it did not haul any passengers or goods. Davidson had trained as a chemist and made a successful business in the production of synthetic yeast for the baking and brewing industries. This gave him time to devote to his hobby of electromagnetism. He designed his own chemical batteries to provide power and, being a practical man, was enthusiastic about the potential of electromagnetism to drive machinery. By 1839 he had designed a printing press, a turning lathe and a four-wheeled car that all used Davidson's batteries and rudimentary electric motor. Davidson decided to demonstrate his inventions to the public and arranged an exhibition of his work, first of all in Aberdeen and subsequently in Edinburgh. He converted his car to run on a circular wooden track for the exhibition and even printed the handbills advertising the show on his electrically-driven printing press. Davidson had such faith in the opportunities that electromagnetism offered that he had his eye on a bigger and more ambitious scheme.

He approached the directors of the Edinburgh and Glasgow Railway for their support in building an electromagnetic railway locomotive. Davidson aimed to show the new railway company that electric locomotives were a practical option. He obtained the endorsement of the Royal Scottish Society for Arts in his ventures and they made him a £15 grant. He built a full size locomotive, Galvani of 1842, which was a four-wheeled machine, 16 feet (4.9 m) long and powered by Davidson's batteries. It was trialled on a section of the Edinburgh to Glasgow line in 1842 and was thus the world's first electrically powered railway locomotive. This was its only claim to fame as the locomotive only managed to achieve a speed of 4 mph (6.4 km/h) and as the batteries were not rechargeable, it was hardly practical. The directors were not sufficiently impressed to ask Davidson to take the concept further. The locomotive was reported as being destroyed whilst stored in the engine house at Perth.

He has been described as a forgotten hero and electrical visionary. He could not interest the rail companies; the technology he employed was too expensive.