Some context: James Watt (30 January 1736 (19 January 1736 OS) - 25 August 1819) was a Scottish inventor, mechanical engineer, and chemist who improved on Thomas Newcomen's 1712 Newcomen steam engine with his Watt steam engine in 1781, which was fundamental to the changes brought by the Industrial Revolution in both his native Great Britain and the rest of the world. While working as an instrument maker at the University of Glasgow, Watt became interested in the technology of steam engines. He realised that contemporary engine designs wasted a great deal of energy by repeatedly cooling and reheating the cylinder. Watt introduced a design enhancement, the separate condenser, which avoided this waste of energy and radically improved the power, efficiency, and cost-effectiveness of steam engines.
From an early age Watt was very interested in chemistry. In late 1786, while in Paris, he witnessed an experiment by Berthollet in which he reacted hydrochloric acid with manganese dioxide to produce chlorine. He had already found that an aqueous solution of chlorine could bleach textiles, and had published his findings, which aroused great interest among many potential rivals. When Watt returned to Britain, he began experiments along these lines with hopes of finding a commercially viable process. He discovered that a mixture of salt, manganese dioxide and sulphuric acid could produce chlorine, which Watt believed might be a cheaper method. He passed the chlorine into a weak solution of alkali, and obtained a turbid solution that appeared to have good bleaching properties. He soon communicated these results to James McGrigor, his father-in-law, who was a bleacher in Glasgow. Otherwise he tried to keep his method a secret. With McGrigor and his wife Annie, he started to scale up the process, and in March 1788, McGrigor was able to bleach 1500 yards of cloth to his satisfaction. About this time Berthollet discovered the salt and sulphuric acid process, and published it so it became public knowledge. Many others began to experiment with improving the process, which still had many shortcomings, not the least of which was the problem of transporting the liquid product. Watt's rivals soon overtook him in developing the process, and he dropped out of the race. It was not until 1799, when Charles Tennant patented a process for producing solid bleaching powder (calcium hypochlorite) that it became a commercial success. By 1794 Watt had been chosen by Thomas Beddoes to manufacture apparatus to produce, clean and store gases for use in the new Pneumatic Institution at Hotwells in Bristol. Watt continued to experiment with various gases for several years, but by 1797 the medical uses for the "factitious airs" had come to a dead end.
What did he do after that?
A:

Some context: Nielsen was born on 11 February 1926 in Regina, Saskatchewan. His mother, Mabel Elizabeth (nee Davies), was an immigrant from Wales, and his father, Ingvard Eversen Nielsen, was a Danish-born constable in the Royal Canadian Mounted Police. Nielsen had two brothers; the elder, Erik Nielsen (1924-2008), was a long-time Canadian Member of Parliament, cabinet minister, and Deputy Prime Minister of Canada from 1984 to 1986. Nielsen's half-uncle Jean Hersholt was an actor known for his portrayal of Dr. Christian in a radio series of that name, and the subsequent television series and films.
Nielsen's career began in dramatic roles on television during "Television's Golden Age", appearing in 46 live programs in 1950 alone. He said there "was very little gold, we only got $75 or $100 per show." He narrated documentaries and commercials and most of his early work as a dramatic actor was uneventful. Hal Erickson of Allmovie noted that "much of Nielsen's early work was undistinguished; he was merely a handsome leading man in an industry overstocked with handsome leading men." In 1956, he made his feature-film debut in the Michael Curtiz-directed musical film The Vagabond King. In the Seattle Post-Intelligencer, Nielsen remembered Curtiz as "a sadist, a charming sadist, but a sadist". Nielsen called this film "The Vagabond Turkey". Though the film was not a success, producer Nicholas Nayfack offered him an audition for the science-fiction film Forbidden Planet, resulting in Nielsen's taking a long contract with Metro-Goldwyn-Mayer (MGM). Forbidden Planet became an instant success, and roles in other MGM films such as Ransom! (1956), The Opposite Sex (1956) and Hot Summer Night (1957) followed. In 1957 he won the lead role opposite Debbie Reynolds in the romantic comedy Tammy and the Bachelor, which, as a Chicago Tribune critic wrote in 1998, made people consider Nielsen a dramatic actor and handsome romantic lead. However, dissatisfied with the films he was offered, calling the studios "a Tiffany, which had forgotten how to make silver", Nielsen left MGM after auditioning for Messala in the 1959 Ben-Hur. Stephen Boyd got the role. After leaving the studios, Nielsen landed the lead role in the Disney miniseries The Swamp Fox, as American Revolutionary War hero Francis Marion. In a 1988 interview, he reflected on the series, saying, "That was a great experience, because the Disney people didn't do their shows like everyone else, knocking out an episode a week. ... We only had to do an episode a month, and the budgets were extremely high for TV at that time. We had location shooting rather than cheap studio backdrops, and very authentic costumes." Eight episodes were produced and aired between 1959 and 1961. His television appearances include Justice, Alfred Hitchcock Presents, Voyage to the Bottom of the Sea, The Virginian, and The Wild Wild West. In 1961, he was the lead in a Los Angeles police drama called The New Breed. He guest-starred in a 1964 episode of Daniel Boone with Fess Parker in a minor but credited role. In 1968, he had a major role in the pilot for the police series Hawaii Five-O, and appeared in one of the seventh-season episodes. In 1969, he had the leading role as a police officer in The Bold Ones: The Protectors. In 1972, Nielsen appeared as the ship's captain in The Poseidon Adventure. He also starred in the William Girdler's 1977 action film, Project: Kill. His last dramatic role before mainly comedy roles was the 1979 Canadian disaster film City on Fire, in which he played a corrupt mayor. In 1980, he guest-starred as Sinclair on the CBS miniseries The Chisholms.
Were all of Nielsen's early films successful?
A:
Forbidden Planet became an instant success,