Arthur James Arnot

Australian electrical engineer

• Born: August 26, 1865
• Birthplace: Hamilton, Scotland
• Died: October 15, 1946
• Place of death: Castle Hill, New South Wales, Australia

Arnot is credited with the invention of the electric drill. His invention was quickly modified by others, who built both large industrial machines and small hand tools for the average handyperson.

Primary fields: Electronics and electrical engineering; mechanical engineering

Primary invention: Electric drill

Early Life

Arthur James Arnot was born in Hamilton, Scotland, on August 26, 1865. His mother was Elizabeth Helen Macdonald Arnot, and his father was William Arnot, a commercial agent. Arthur attended Hutchisontown Grammar School and Haldane Academy in Glasgow, and in 1881 he began studies at the West of Scotland Technical College in Glasgow. He moved to London to continue his studies part-time while working for an electrical engineering company. In 1885, he became an assistant engineer at the Grosvenor Gallery power station, a privately owned generating station established by Sir Coutts Lindsay to provide electricity to light an art exhibit. The station was run by the engineer Sebastian Ziani de Ferranti, himself only twenty-three years old at the time Arnot was hired. Ferranti, a prolific inventor, made great improvements to the station’s ability to transmit high-voltage power. By 1886, he had made the station the largest and most efficient supplier of public electricity in England. Working with Ferranti on an expanding project gave Arnot an unparalleled chance to experiment and innovate, and to learn the new business of producing and supplying electricity.

Arnot left the United Kingdom for Australia in 1889, under a two-year contract to build a large alternating-current-generating plant for the newly formed Union Electric Company in Melbourne, a city in the state of Victoria. He spent nearly the rest of his career and life in Australia.

Life’s Work

Arnot designed and oversaw the building and management of Melbourne’s Spencer Street Power Station, a coal-fired station that provided power for the city and sold surplus power to other municipal distributors. In March, 1891, the city council named Arnot Melbourne’s first electrical engineer. He held the post until 1901, making occasional extended trips to England and the United States to keep up with new innovations in electrical engineering. In August, 1891, Arnot married Cornelia Ann, the daughter of one of the city councilors. At this time, the main use of municipal electricity was for lighting (electrical appliances and machines had not yet been developed). In 1891-1892, Arnot installed an array of electric streetlights in the city, replacing the gaslights that had been installed in the 1850’s. He modeled his “series arc and incandescent system” on the system already in use in London and the United States. Soon, the central business district of Melbourne was illuminated with electric lights from a central source—a first in Australia.

Electricity generation at the end of the nineteenth century was a dangerous and largely unregulated enterprise, and many entrepreneurs, with varying degrees of expertise, set up their own generating stations and sold power to their neighbors. In 1896, Arnot drafted an Electric Light and Power Act that was passed by the parliament of the state of Victoria. Under the terms of this act, people could generate power for their own use but could not supply to others without a license.

Arnot had a long and distinguished career as an engineer in Melbourne, but his most lasting achievement as an inventor came during his first year in Australia. While he was engaged in the construction of the Union Electric Company’s electrical plant, he sought a better way to dig coal and to drill foundation holes in rock. On August 20, 1889, he along with mining engineer William Blanch Brain and Frank Baker patented the world’s first electric drill, which they called “an improved electrical rock-drill, coal-digger, or earth-cutter.” Although the patent clearly names all three men (in fact, Brain’s name appears first), Arnot is usually given sole credit for the invention. Arnot also worked on refinements to the electric motor that powered his drill, and in 1891 he was granted a patent for an improved alternating-current (AC) motor. Unlike the small hand drills common in the twenty-first century, Arnot’s drill was a large industrial machine.

Known as a hardworking and creative man, Arnot was profiled as one of several “Coming Men” in a series of articles in the Australian science journal Table Talk in 1893. In 1899, he was elected a member of the Institution of Electrical Engineers in London and to the presidency of both the Victorian Institute of Electrical Engineers and the Electrical Association of New South Wales. During his time as Melbourne’s electrical engineer, it seemed that direct current (DC) was superior to alternating current, and Arnot oversaw a substantial expansion of the DC grid during his tenure. With the later development of improved AC motors, however, it became apparent that alternating current was preferable, and a large amount of money and resources were spent in rewiring. In 1899, Arnot traveled to England and the United States to gather more opinions in the contentious battle between DC and AC.

In 1901, Arnot left Melbourne for Sydney to take the position of Australasian manager for Babcock and Wilcox, a large American firm that designed, engineered, built, and managed large steam-powered electrical generating stations. Babcock and Wilcox had provided some of the boilers for the Spencer Street Power Station. In this position, Arnot helped smaller cities and private power companies throughout Australasia build and manage electrical power plants using Babcock and Wilcox designs and equipment.

On September 29, 1904, Arnot’s son Frederick Latham was born. Frederick went on to become a university lecturer in natural philosophy and later physics. Arnot joined the city council while in Sydney, and he was implicated in a corruption scandal involving the council’s contract for a steam-raising plant. It was charged that he had paid a bribe to have his company’s boilers chosen for the project. He was formally censured by Judge John Musgrave Harvey in 1928. Arnot retired from Babcock and Wilcox the next year.

During his years in Sydney, Arnot also participated in the military. He was commissioned a lieutenant in the Submarine Mining Company, Victorian Engineers, in 1894, when he was twenty-nine. The Victorian Engineers was part of a volunteer force defending the colony of Victoria. (The Commonwealth of Australia would not be established until 1901.) The Submarine Mining Company set explosives on the ocean floor and triggered them from shore. In 1915, near the beginning of World War I, Arnot joined the Australian Engineers, Australian Military Forces. At age fifty, he was unable to join his countrymen fighting with the Allies at the western front, but he could lend his expertise as an engineer. In 1916, he took command of the Sydney field companies and reinforcement camps. He retired from the military in 1925 with the rank of major.

Arnot lived quietly after his retirement from Babcock and Wilcox. He moved to Castle Hill in New South Wales, where he died on October 15, 1946.

Impact

As an engineer, Arnot played an important role in the electrification of Australia. It is one thing to power a light bulb in a laboratory, and quite another to light an entire city. Arnot’s design for the Spencer Street Power Station put Melbourne on the electrical map, and Arnot successfully managed the plant for more than a decade in which understanding of electricity and of electrical engineering grew at a rapid pace. The story of the early years of the power station includes controversies over the new field of electrification: the uses of AC and DC power, the struggles between municipal and private companies, the movement toward the standardization of amperes transmitted, and the rush to obtain coal for steam generation.

Arnot left his mark as an inventor. His need for a large and steady supply of coal for his Spencer Street Power Station led him and his colleagues Brain and Baker to use one of the new electric motors to power a drill to dig through rock more quickly than other methods. They could not have foreseen that this large industrial machine would become a common tool within forty years. From the tiny drills used in dentistry, to small handheld drills in the toolboxes of carpenters and homeowners, to large electric rock drills used in mining, the electric drill has played an important role in making work easier in the age of technology.

Bibliography

Creswell, Toby, and Samantha Trenoweth. One Thousand One Australians You Should Know. North Melbourne: Pluto Press Australia, 2006. Brief illustrated biographies of important Australians, including Arnot—in “Science, Invention, and Ideas.”

Nagyszalanczy, Sandor. Power Tools: An Electrifying Celebration and Grounded Guide. Newtown, Conn.: Taunton Press, 2001. This illustrated guide is intended for consumers. Its section on “Drills and Drivers” includes a brief history, an exploded diagram showing how the modern electric hand drill works, and an analysis of different drills and their uses.

Smil, Vaclav. Creating the Twentieth Century: Technical Innovations of 1867-1914 and Their Lasting Impact. New York: Oxford University Press, 2005. An interdisciplinary history of innovation, including the generation and distribution of electricity.