1921 deaths

Colonel John Herschel (29 October 1837 – 31 May 1921) was an English military engineer, surveyor and astronomer. He was the son of Sir John Herschel, 1st Baronet, and grandson of William Herschel.

Léon Ernest Moreaux (10 March 1852 in Féron – 11 November 1921 in Rennes) was a French sports shooter and Olympian who competed in pistol and rifle shooting in the late 19th century and early 20th century.Having taken up the sport of shooting earlier in the 19th century, at the age of 38 he prepared himself for competition in the 1900 Olympic Games, which were held in Paris in his home country. He participated in shooting at the 1900 Summer Olympics and won the silver medal in the 25 metre firearm and in the Military Revolver Teams 50m for France and won another silver medal. He also competed in a number of other shooting competitions including the Free Rifle standing and kneeling competitions, where he finished 17th place in each, and in the Free Rifle (prone) competition where he narrowly missed the bronze medal, finishing fourth. He also competed in the Free Pistol event where he finished in 7th place, and in the trap shooting competition where he finished 16th place out of 31.
1906 was Moreaux's most successful year in sport shooting. In shooting at the 1906 Intercalated Games he entered in ten different categories, winning a total of five Olympic medals including his first gold medals. He won two gold medals in the 20m duelling pistol and in the 200 metre army rifle, a silver medal in the 25 metres firearm, and two bronze medals in the Free Rifle Free Position and the Free Rifle Team. Moreaux competed in the Military Rifle event and finished fourth, in the Military revolver event and finished fifth, and in the Duelling Pistol (au commandment), finishing in sixth place. He also competed in the Military revolver (gras) event but finished in 16th place and in the Free Pistol (50m) event, finishing in 19th position.
Moreaux entered the 1908 Olympic Games at the age of 46 and competed in the Free Team Rifle competition for France, but narrowly missed bronze, finishing in fourth position. At this point in his career, only four years away from age 50, he only competed in two other events – in the Free Pistol, finishing 17th, and in the Free Rifle Combined event, where he finished in 39th place.
After the 1908 Olympics, Moreaux retired from professional competition. He won 8 Olympic medals during his shooting career, second to only Switzerland's Konrad Stäheli (9) among his contemporaries and still among the top ten in Olympic shooting history.

Johanna Elisabeth Repelius, known as Betsy (31 January 1848 in Amsterdam – 23 January 1921 in Amsterdam) was a Dutch painter and watercolorist who specialized in simple, one-figure, genre scenes.

Julius Richard Petri (31 May 1852 – 20 December 1921) was a German microbiologist who is generally credited with inventing the device known as the Petri dish, which is named after him, while working as assistant to bacteriologist Robert Koch.

Gustav Killian (2 June 1860 – 24 February 1921) was a German laryngologist and founder of the bronchoscopy.

Marie Georges Humbert (7 January 1859 Paris, France – 22 January 1921 Paris, France) was a French mathematician who worked on Kummer surfaces and the Appell–Humbert theorem and introduced Humbert surfaces. His son was the mathematician Pierre Humbert. He won the Poncelet Prize of the Académie des Sciences in 1891.
He studied at the École Polytechnique. He was the brother-in-law of Charles Mangin.

Alfred Grandidier (20 December 1836 – 13 September 1921) was a French naturalist and explorer.
From a very wealthy family, at the age of 20, he and his brother, Ernest Grandidier (1833–1912), undertook a voyage around the world. At first they were led by the astronomer and physicist Pierre Jules César Janssen (1824–1907), but when Janssen fell sick and had to return to France after about six months, the brothers continued the journey.
They visited South America in 1858 and 1859 and in particular the Andes, Peru, Chile, Bolivia, Argentina and Brazil. During this voyage they gathered a significant collection of specimens which were analyzed, in 1860, by Ernest.
The two brothers parted ways after this. Ernest Grandidier went to China and collected a vast number of specimens which are now in the Louvre and the Guimet museum. Alfred travelled to India, reaching it in 1863. He had intended to explore the high plateau of Tibet, but was prevented by a severe attack of fever.
Grandidier travelled to Zanzibar to recuperate, remaining some time and making important collections and publishing an account of his findings. He then visited the island of Réunion and in 1865 made his first visit to Madagascar. He became devoted to the study of the island, revisiting in 1866 and 1868. He finally returned permanently to France in 1870. During his explorations he crossed the island three times, travelling 3000 kilometers in the interior and 2500 along the coast. He made observations which resulted in the production of a map of the island used in future expeditions.

After returning to France he began to work on his great work, L'Histoire physique, naturelle et politique de Madagascar. This work was undertaken in cooperation with others such as Alphonse Milne-Edwards and Leon Vaillant. This work ran to 40 volumes, the final volumes published posthumously by his son Guillaume Grandidier. He described about 50 new species of reptiles and amphibians.Alfred Grandidier's work drew the attention of the French government to Madagascar, which it would annex at the end of 1890.
He was elected to the French Academy of Sciences in 1885 and was the president of the French Geographical Society from 1901 to 1905. The Royal Geographical Society awarded him their Founder's Medal in 1906.

Charles-Émile François-Franck (7 May 1849, Paris – 8 September 1921, Paris) was a French physiologist.
From 1871 he served as a hospital intern in Bordeaux, later returning to Paris, where he worked as an assistant to Étienne-Jules Marey in the laboratory of pathophysiology at the Collège de France. In 1885 he was named director of the laboratory, and in 1890, attained the title of professor. Among his assistants at the Collège de France was neuropathologist Gustave Roussy. In 1887 he was elected as a member of the Académie Nationale de Médecine.His research included studies of vasomotor regulation, pulmonary blood flow and investigations involving the cerebral localization of function. He was a pioneer of sympathectomy (interruption of the sympathetic nervous system for relieving pain) and remembered for his usage of cinematography to accurately record body movements.

Jules Carpentier (30 August 1851 – 30 June 1921) was a French engineer and inventor.
Jules Carpentier was a student at the French École polytechnique.
He bought the Ruhmkorff workshops in Paris when Heinrich Daniel Ruhmkorff died and made it a successful business for building electrical and magnetical devices. From 1890, he started to build photographic and cinematographic cameras. He is the designer of the submarine periscope, and worked at the adjustment of trichromic process of colour photography.
He patented the "Cinématographe", which serves as a film projector and developer in the late 1890s, and built devices from the Lumière Brothers.
Another of his patents, filed in England, was a primary reference of Theodor Scheimpflug, who disclaimed inventing the falsely eponymous Scheimpflug principle.He died in 1921 in a car accident in Joigny, France.

Émile Bourquelot (21 June 1851 – 26 January 1921) was a French chemist, and professor of pharmacy at the University of Paris. He was born in Jandun (Ardennes, France), to a farmer, and was the eldest of three sons. Bourquelot became the Chief Pharmacist at the Laënnec Hospital in 1887, where he established a laboratory to conduct his research into carbohydrate chemistry. Bourquelot and other French pharmacists pioneered the study of plant glycosides, molecules in which a sugar is bound to a non-carbohydrate part. They developed methods to stabilize these compounds in solution, and detect them enzymatically. He died at the age of 70 on 26 January 1921 of pneumonia.
The French Academy of Sciences awarded him the Prix Montagne for 1897.