Rudolph Melville Hunter (June 20, 1856 – March 19, 1935) was an American inventor, engineer, patent attorney and entrepreneur. Hunter was granted 299 US patents, over 140 of them for electric railway apparatus. He played a key role in the development of "mixed control," long the standard method of controlling the speed of electric streetcars and locomotives. Hunter later largely abandoned his work as a practical inventor and devoted himself to a futile (despite his claims of success) quest to transmute silver and other metals into gold.