Parsons, Sir Charles Algernon (1854–1931), engineer and scientist, was born 13 June 1854 in London, youngest among eleven children of William Parsons (qv), 3rd earl of Rosse, of Parsonstown (Birr), King's Co. (Offaly) and Mary Parsons (née Field), a Yorkshire heiress. Only four sons survived to adulthood. Charles was strongly influenced by his father, who encouraged him to use the workshops at the Birr Castle observatory, and he was tutored at home by some of the assistant astronomers before entering TCD (1871). He transferred to St John's College, Cambridge, and on graduation (1877) as eleventh wrangler in a class of thirty-six studying mathematics, he took the unusual step, for the son of an earl, of becoming a premium apprentice at the Elswick Engine and Ordnance Works (more usually, the ‘Elswick Works’) of Sir W. G. Armstrong at Newcastle upon Tyne. In the period following this he developed a unique high-speed steam engine, and a torpedo which was powered by a gas turbine. He joined Clarke Chapman at Gateshead as a partner in 1884. In a matter of months he filed patents for the world's first effective steam turbine. These embodied many novelties, but the key feature was an electricity generator rated at 6 kW and designed to run, directly coupled, at the astonishing speed of 18,000 rpm.
He was not satisfied that his partners' efforts to promote turbine development were sufficiently aggressive, and in 1889 he left to establish his own company at Heaton near Newcastle upon Tyne. The price of this impetuous action was the loss of access to his original patents. He quickly established alternative designs and by 1892 he had built a turbo-alternator with an output of 100 kW for the Cambridge Electricity Company; exhausting to a condenser, it had a steam consumption comparable with the best steam engines. Even his 1884 patents envisaged applying turbines to marine propulsion, but it was 1893 before he could embark on the design of a suitable demonstration boat of 40 tons. By using careful tests on models he perfected the hull shape and predicted the power requirements. At this time he recovered his 1884 patents and even won the very rare prize of an extension for five years, which was a measure of the perceived national importance of his invention.
A syndicate was formed to raise the capital necessary to build his turbine-powered vessel Turbinia. At the Spithead naval review in 1897 she sped among the ships of the world's navies at 34.5 knots. In 1905 the Royal Navy decided to adopt turbines for its future warships. This example was followed by navies worldwide, from the USA to Japan. Builders of mercantile vessels followed quickly and the turbines of the Cunard liner Mauretania (1907), each developing 26,000 kW, were the largest in existence at the time. The Mauretania held the Blue Riband for the speediest Atlantic crossing until 1929, a fact that kept Parsons's name before the public.
The firm of C. A. Parsons (1889), which built turbines for use on land, was privately owned, but the Parsons Marine Steam Turbine Co. (1897) was a public company. Parsons also earned income from over 300 patents through the Parsons Foreign Patents Co. (1899). He readily licensed others to use his patents but he avoided costly litigation, the ruin of many inventors. He inherited an interest in optical instruments from his father. In 1890 he developed a cost-effective method for manufacturing searchlight mirrors, using sheets of plate glass and an iron mould heated in a gas furnace. During the first world war he supplied most of the national requirements. In 1921 he acquired the optical instrument manufacturers Ross Ltd and the Derby Crown Glass Company, makers of optical quality glass. In 1925 the firm of Howard Grubb, which made large astronomical telescopes, was rescued from insolvency by Parsons. He believed that it was of national importance to maintain the industrial capacity to make optical equipment. Not all of his projects were commercially profitable, as for example his acoustic amplifier, dubbed the ‘Auxetophone', or his attempts at synthesising diamonds, which absorbed much time and effort. In the development of his many inventions he displayed great tenacity in the face of reverses and always employed a meticulously scientific approach.
The supply of power on a large scale was revolutionised by the steam turbine. During the twenty years following the building of his first turbo-generator Parsons remained at the forefront of promoting, building, and selling ever larger and more efficient turbines. He was not only a scientific engineer and inventor, but also a successful manufacturer and businessman. Modest and retiring in manner, his chief weakness lay in a lack of skill in managing interpersonal relationships, though this was compensated to a large extent by his integrity and loyalty. He sought out the ablest men to run his businesses, among them several Fellows of the Royal Society. He was elected FRS himself in 1898, and was knighted in 1911. In 1927 for his outstanding contributions to society he became the first engineer to be awarded the Order of Merit. He was honoured by many universities and institutions in Europe and America.
He married (1883) Katharine Bethell, a Yorkshire woman, and had one daughter and a son who died on active service in 1918. He kept a residence in London and in Northumbria. He died on 11 February 1931 while on a cruise to the Caribbean. He was buried at Kirkwhelpington near his Northumbrian home. His estate was valued at £1,214,355 gross. A portrait painted by Maurice Codner hangs in the Institution of Mechanical Engineers, London; there is also a portrait by Sir William Orpen (qv) in the Laing Art Gallery, Newcastle upon Tyne, and a portrait by Walter Stoneman in the National Portrait Gallery, London.