William Herschel , THE INVENTOR OF PLANET URANUS , FIRST GLASS PHOTO MADE ON 1839 SEPT 9

William Herschel ,

THE INVENTOR OF PLANET URANUS , FIRST GLASS PHOTO MADE ON 1839 SEPT 9

Sir John Frederick William Herschel, 1st Baronet KH FRS (7 March 1792 – 11 May 1871)[1] was an English polymath, mathematician, astronomer, chemist, inventor, and experimental photographer, who also did valuable botanical work.[1] He was the son of Mary Baldwin and astronomer William Herschel, nephew of astronomer Caroline Herschel and the father of twelve children.[1]

Herschel originated the use of the Julian day system in astronomy. He named seven moons of Saturn and four moons of Uranus. He made many contributions to the science of photography, and investigated colour blindness and the chemical power of ultraviolet rays; his Preliminary Discourse (1831), which advocated an inductive approach to scientific experiment and theory building, was an important contribution to the philosophy of science.[2

Photography[edit]

Herschel's first glass-plate photograph, dated 9 September 1839, showing the 40-foot telescope[16]
Herschel made numerous important contributions to photography. He made improvements in photographic processes, particularly in inventing the cyanotype[17] process and variations (such as the chrysotype), the precursors of the modern blueprint process. In 1839, he made a photograph on glass, which still exists, and experimented with some color reproduction, noting that rays of different parts of the spectrum tended to impart their own color to a photographic paper. Herschel made experiments using photosensitive emulsions of vegetable juices, called phytotypes and published his discoveries in the Philosophical Transactions of the Royal Society of London in 1842.[18] He collaborated in the early 1840s with Henry Collen, portrait painter to Queen Victoria. Herschel originally discovered the platinum process on the basis of the light sensitivity of platinum salts, later developed by William Willis.[19]

Herschel coined the term photography in 1839.[20] He may however have been preceded by Brazilian Hércules Florence, who used the French equivalent, photographie, to describe his own experiments in private notes in 1834,[21] although as Florence was not in communication with the European scientific community, Herschel has historically been credited with coining and popularising the term.[22] Herschel was also the first to apply the terms negative and positive to photography.[1]

He discovered sodium thiosulfate to be a solvent of silver halides in 1819,[23] and informed Talbot and Daguerre of his discovery that this "hyposulphite of soda" ("hypo") could be used as a photographic fixer, to "fix" pictures and make them permanent, after experimentally applying it thus in early 1839. His ground-breaking research on the subject was read at the Royal Society in London in March 1839 and January 1840.

General[edit]

Tombs of John Herschel and Charles Darwin. Westminster Abbey.

Description of a machine for resolving by inspection certain important forms, 1832
Herschel wrote many papers and articles, including entries on meteorology, physical geography and the telescope for the eighth edition of the Encyclopædia Britannica.[1] He also translated the Iliad of Homer.

Further information: English translations of Homer § Herschel
He invented the actinometer in 1825 to measure the direct heating power of the sun's rays,[24] and his work with the instrument is of great importance in the early history of photochemistry.

He 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.[25] 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).[26]

Hershel was elected a Foreign Honorary Member of the American Academy of Arts and Sciences in 1832,[27] 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.[28]

The village of Herschel in western Saskatchewan (Canada), 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 name, about which John Herschel’s father (Sir William Herschel) and his aunt (Caroline Herschel) are two other notable members of this family.[29]
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