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.
Early life and education Hunter's father, Robert, was a physician specializing in respiratory disorders. Canadian by birth, he married Sarah Barton, also Canadian, in 1846. Rudolph was born in New York City, the fifth of the couple's eight children who survived infancy.
Robert Hunter, an inventor in his own right, was granted seven US patents for marine propulsion systems (including one for a mechanical toy fish). The last of those patents (No. 150,956), issued in May 1874, was for an innovative design that he had introduced in a canal boat in 1872. Lured by a $100,000 prize, he entered the boat in a New York State-sponsored contest to design a viable steam propulsion system for use on the state's canals. Hunter's design featured two stern-mounted, vertically oriented paddlewheels that rotated in opposite directions, in order to control wake. The pitch of the wheels' blades could be adjusted to steer the boat without the use of a rudder or to move it in reverse without reversing the engine. Unfortunately, the system proved impracticable, and the boat failed to complete its trial runs.
From childhood Rudolph was strongly encouraged to invent,Hunter Testimony, p. 70; Interference Case No. 13,298, Sprague v. Hunter v. Van Depoele; Interference Case Files, 1836-1905; Records of the Patent Office, Record Group 241; National Archives at College Park, MD. and one of his early inventions appears to have been inspired by his father's canal-boat work. In 1878, at age 22, he sketched a rudderless submarine equipped with two side-mounted screw propellers. The propellers could be pivoted to point backward, forward, up or down, thereby moving the vessel in any direction. He refined the design and in the 1880s tried to sell it to the US Navy and foreign governments.Hunter, Rudolph M. (c. 1883). Hunter's submarine vessel and fish torpedo. Philadelphia?: Self-published?. [promotional brochure received by the US Navy Department Library in 1883] He failed to find a buyer, however, and he did not patent the design.
Hunter attended schools in England, France and Canada before embarking, at age 15, on his career path. In 1871 he started work as a draftsman for Frank Millward, in Cincinnati, Ohio. Millward did engineering and patent work, and Hunter, while in his employ, diligently studied engineering. In 1874 Hunter took his newfound engineering skills to Olive Foundry & Machine Shops, in Ironton, Ohio, where he designed and built machinery. By 1876 he had moved to Chicago, Illinois, in part to seek proper care (most likely from his father, who had moved there from Cincinnati) for respiratory troubles. Later that year he moved to Philadelphia, where he resumed his formal education.Hunter Testimony, pp. 69-74; IC 13,298, Sprague v. Hunter v. Van Depoele; ICF 1836-1905; RG 241; NACP. Hunter, in testimony presented in this patent interference case, detailed his early work experiences and the means by which he became a skilled engineer. He studied mechanical engineering at the Polytechnic College of the State of Pennsylvania, earning a bachelor's degree in 1878. He settled permanently in Philadelphia and in October 1879 married Emilie Phillips, daughter of a Pittsburgh, Pennsylvania, physician.
Career
By late 1878 Hunter had established an office in Philadelphia to offer his services as a consulting engineer and patent attorney. In June 1879 he secured his first patent (No. 216,519), for a "process and apparatus" for making illuminating gas. He eventually held 299 US patents, 279 of them issued by 1902. He also secured seven Canadian and six British patents, all for inventions on which he also held a US patent. His inventions ranged from mechanical toys to industrial machinery, but most were for electrical devices and systems. Throughout his career as an inventor, he continued to work as a patent attorney, representing himself in numerous patent interference cases, in addition to serving outside clients.
Electric railways Hunter's primary focus, early in his career, was on the development of electric railways. From 1881 to 1886 he struggled to secure financing to patent and commercialize his many inventions in the field. But with the formation of Electric Car Company of America (originally named Hunter Electric Co.), in 1887, he finally had the resources to build and market electric street-railway systems.Hunter Testimony, pp. 26-29, 64-68; IC 13,298, Sprague v. Hunter v. Van Depoele; ICF 1836-1905; RG 241; NACP. Electric Car's prospects quickly dimmed, however, largely due to the success of other inventors and to the efforts of major electrical firms to develop their own street-railway businesses. In 1888 Frank J. Sprague completed the Richmond Union Passenger Railway, widely considered the first successful large-scale electric street-railway system. Sprague had close ties to Thomas Edison's organization, and in April 1889 his company became part of the newly incorporated Edison General Electric Co. Over a year earlier, Thomson-Houston Electric Co. had bought out Sprague's chief rival, Charles Van Depoele, and in August 1889 Thomson-Houston bought partial rights to Electric Car's patents, the bulk of which were Hunter's. Edison General and Thomson-Houston were locked in fierce competition, one aspect of which was costly and time-consuming patent litigation. By early 1892 both companies were eager to end the rivalry, and in April they did so, by merging. One of the merger's key benefits was to consolidate control of the Sprague, Van Depoele, and Electric Car patents (and many other patents) in the resulting corporate giant, General Electric Co.
The sale of Electric Car's patent rights, though it may have dashed any grand hopes Hunter had for the company, made him a wealthy man. In a December 1894 letter to Franklin Institute secretary William H. Wahl, Hunter intimated that the deal had netted him more than $600,000 (more than $15,000,000 in 2018 dollars).Rudolph M. Hunter to William H. Wahl, December 15, 1894. Franklin Institute Awards Case Files, files 1836-1837 (combined). Franklin Institute. Philadelphia. That figure is unverified and may be exaggerated, but there is little doubt that Thomson-Houston considered his patents valuable. In an 1891 publication, the company listed the 82 "most important" electric railway patents under its control. A surprising 27 of them, more than for any other inventor, were Hunter's. And it is clear that his financial situation and lifestyle improved dramatically at about the time of the sale. In December 1889, after years of living in rented quarters, he moved into a castle-like mansion he built in West Philadelphia.Hunter Testimony, pp. 50, 68; Interference Case No. 15,832, Hopkinson v. Hunter; Interference Case Files, 1836-1905; Records of the Patent Office, Record Group 241; National Archives at College Park, MD. By 1893 he had crowned the structure with a rooftop street-railway line, which he used, he told The Philadelphia Press, to test and apply new designs.
In 1894, hoping to gain recognition for his electric railway work, Hunter entered an annual competition conducted by the Franklin Institute's Committee on Science and the Arts. In a June 26 letter to Wahl, he audaciously claimed to have invented the "modern electric railway" virtually in its entirety.Rudolph M. Hunter to William H. Wahl, June 26, 1894. Franklin Institute Awards Case Files, files 1836-1837 (combined). Franklin Institute. Philadelphia. On his official entry forms, submitted a few days earlier, he was more realistic, claiming credit mainly for two of the electric street-railway's key elements: the "trolley system" (specifically, a viable underrunning trolley assembly) and the "series-multiple controller" (a speed- and torque-control switch, better known as the "series-parallel controller").Rudolph M. Hunter entry forms, June 21, 1894. Franklin Institute Awards Case Files, files 1836-1837 (combined). Franklin Institute. Philadelphia.
A report on Hunter's entry concluded that other inventors had received at least partial credit for the underrunning trolley and that it was up to "the courts," not the Committee on Science and the Arts, to determine priority of invention.Subcommittee report to the Committee on Science and the Arts, November 28, 1894. Franklin Institute Awards Case Files, files 1836-1837 (combined). Franklin Institute. Philadelphia. The committee declined, therefore, to give him an award. Hunter was outraged, though the committee's decision clearly was justified. Nearly two years earlier, the US Patent Office had granted priority of invention to Van Depoele, who had prevailed against both Sprague and Hunter in a landmark interference case.Decision of the examiner of interferences, December 15, 1892; IC 13,298, Sprague v. Hunter v. Van Depoele; ICF 1836-1905; RG 241; NACP. Van Depoele's patent (No. 495,443), issued posthumously and assigned to Thomson-Houston, was extremely valuable and, not surprisingly, hotly contested in the courts. In a string of infringement suits brought by Thomson-Houston on GE's behalf, the courts repeatedly affirmed the patent's validity, thereby giving GE a virtual monopoly on the practical underrunning trolley.The first and probably most significant of those suits was Thomson-Houston Electric Co. v. Winchester Avenue Railway Co. et al. (73 O.G., 2155). United States Patent Office (1896). Decisions of the commissioner of patents and of the United States courts in patent and trade-mark and copyright cases. 1895. Washington, DC: Government Printing Office. pp. 788–806. Winchester was a licensee of codefendant Westinghouse Electric and Manufacturing Co., so the case essentially pitted GE against its most formidable rival, Westinghouse.
The series-parallel controller had also been the subject of an interference battle. Hunter held a US patent (No. 385,055), issued in June 1888, for the device, but a British patent (Great Britain No. 2989 of 1881) had been granted to electrical engineer John Hopkinson over six years earlier. Hopkinson applied for a US patent in 1892, triggering an interference case. Hunter presented evidence that he had conceived his controller before Hopkinson's formal (for purposes of the case) date of invention, but Hopkinson nonetheless was granted priority of invention. Hunter, the examiner of interferences explained, had failed to show sufficient diligence in reducing his device to practice, prior to Hopkinson's date of invention.Decision of the examiner of interferences, April 19, 1895; IC 15,832, Hopkinson v. Hunter; ICF 1836-1905; RG 241; NACP. Hopkinson's British patent expired, however, before the case was resolved. That made him ineligible for a US patent (which, if issued, would have expired concurrently with his British patent), and Hunter's patent therefore remained in force.Hopkinson v. Hunter (74 O.G., 653). United States Patent Office (1897). Decisions of the commissioner of patents and of the United States courts in patent and trade-mark and copyright cases. 1896. Washington, DC: Government Printing Office. pp. 1-5.