page_title: John Herschel
section_title: Other aspects of Herschel's career
hierarchical_section_title: John Herschel / Other aspects of Herschel's career
caption_attribution_description: English: John Herschel (1815-1879), photographed by Julia Margaret Cameron in April 1867. Image: 31.8 x 24.9 cm (12 1/2 x 9 13/16 in.) Mount: 39.9 x 32.9 cm (15 11/16 x 12 15/16 in.)
context_page_description: Sir John Frederick William Herschel, 1st Baronet KH FRS was an English polymath, mathematician, astronomer, chemist, inventor, experimental photographer who invented the blueprint, and did botanical work.
  Herschel originated the use of the Julian day system in astronomy. He named seven moons of Saturn and four moons of Uranus – the seventh planet, discovered by his father Sir William Herschel. He made many contributions to the science of photography, and investigated colour blindness and the chemical power of ultraviolet rays. His Preliminary Discourse, which advocated an inductive approach to scientific experiment and theory-building, was an important contribution to the philosophy of science.
context_section_description: Herschel wrote many papers and articles, including entries on meteorology, physical geography and the telescope for the eighth edition of the Encyclopædia Britannica. He also translated the Iliad of Homer.
  In 1823, Herschel published his findings on the optical spectra of metal salts.
  Herschel invented the actinometer in 1825 to measure the direct heating power of the sun's rays, and his work with the instrument is of great importance in the early history of photochemistry.
  Herschel proposed a correction to the Gregorian calendar, making years that are multiples of 4000 not leap years, thus reducing the average length of the calendar year from 365.2425 days to 365.24225. Although this is closer to the mean tropical year of 365.24219 days, his proposal has never been adopted because the Gregorian calendar is based on the mean time between vernal equinoxes (currently 365.242374 days).
  Herschel was elected a Foreign Honorary Member of the American Academy of Arts and Sciences in 1832, and in 1836, a foreign member of the Royal Swedish Academy of Sciences.
  In 1835, the New York Sun newspaper wrote a series of satiric articles that came to be known as the Great Moon Hoax, with statements falsely attributed to Herschel about his supposed discoveries of animals living on the Moon, including batlike winged humanoids.
  The village of Herschel in western Saskatchewan Canada (site of the discovery of  Dolichorhynchops herschelensis, a type of short-necked plesiosaur,) Mount Herschel Antarctica, the crater J. Herschel on the Moon, and the Herschel Girls' School in Cape Town South Africa, are all named after him.
  While it is commonly accepted that Herschel Island, in the Arctic Ocean, part of the Yukon Territory, was named after him, the entries in the expedition journal of Sir John Franklin state that the latter wished to honour the Herschel family, of which John Herschel's father, Sir William Herschel, and his aunt, Caroline Herschel, are as notable as John.
caption: 1867 photograph by Julia Margaret Cameron
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