1. John Herschel made many contributions to the science of photography, and investigated colour blindness and the chemical power of ultraviolet rays.
31 Facts About John Herschel
1. 2.
John Herschel's Preliminary Discourse, which advocated an inductive approach to scientific experiment and theory-building, was an important contribution to the philosophy of science.
3.
John Herschel was born in Slough, Buckinghamshire, the son of Mary Baldwin and astronomer Sir William John Herschel.
4.
John Herschel studied shortly at Eton College and St John's College, Cambridge, graduating as Senior Wrangler in 1813.
5.
John Herschel left Cambridge in 1816 and started working with his father.
6.
John Herschel took up astronomy in 1816, building a reflecting telescope with a mirror 18 inches in diameter, and with a 20-foot focal length.
7.
John Herschel was one of the founders of the Royal Astronomical Society in 1820.
8.
John Herschel described nature as being governed by laws which were difficult to discern or to state mathematically, and the highest aim of natural philosophy was understanding these laws through inductive reasoning, finding a single unifying explanation for a phenomenon.
9.
John Herschel was elected as a member to the American Philosophical Society in 1854.
10.
John Herschel published a catalogue of his astronomical observations in 1864, as the General Catalogue of Nebulae and Clusters, a compilation of his own work and that of his father's, expanding on the senior John Herschel's Catalogue of Nebulae.
11.
John Herschel correctly considered astigmatism to be due to irregularity of the cornea and theorised that vision could be improved by the application of some animal jelly contained in a capsule of glass against the cornea.
12.
Discoveries of John Herschel include the galaxies NGC 7, NGC 10, NGC 25, and NGC 28.
13.
John Herschel declined an offer from the Duke of Sussex that they travel to South Africa on a Navy ship.
14.
John Herschel collaborated with Thomas Maclear, the Astronomer Royal at the Cape of Good Hope and the members of the two families became close friends.
15.
John Herschel combined his talents with those of his wife, Margaret, and between 1834 and 1838 they produced 131 botanical illustrations of fine quality, showing the Cape flora.
16.
John Herschel used a camera lucida to obtain accurate outlines of the specimens and left the details to his wife.
17.
John Herschel returned to England in 1838, was created a baronet, of Slough in the County of Buckingham, and published Results of Astronomical Observations made at the Cape of Good Hope in 1847.
18.
John Herschel made improvements in photographic processes, particularly in inventing the cyanotype process, which became known as blueprints, and variations, such as the chrysotype.
19.
John Herschel made experiments using photosensitive emulsions of vegetable juices, called phytotypes, known as anthotypes, and published his discoveries in the Philosophical Transactions of the Royal Society of London in 1842.
20.
John Herschel collaborated in the early 1840s with Henry Collen, portrait painter to Queen Victoria.
21.
John Herschel originally discovered the platinum process on the basis of the light sensitivity of platinum salts, later developed by William Willis.
22.
John Herschel was the first to apply the terms negative and positive to photography.
23.
John Herschel discovered sodium thiosulfate to be a solvent of silver halides in 1819, and informed Talbot and Daguerre of his discovery that this "hyposulphite of soda" could be used as a photographic fixer, to "fix" pictures and make them permanent, after experimentally applying it thus in early 1839.
24.
John Herschel's ground-breaking research on the subject was read at the Royal Society in London in March 1839 and January 1840.
25.
In 1823, John Herschel published his findings on the optical spectra of metal salts.
26.
John 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.
27.
John Herschel proposed a correction to the Gregorian calendar, making years that are multiples of 4000 common years rather than leap years, thus reducing the average length of the calendar year from 365.2425 days to 365.24225.
28.
John 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.
29.
Several locations are named for him: the village of Herschel in western Saskatchewan, Canada, site of the discovery of Dolichorhynchops herschelensis, a type of plesiosaur; Mount Herschel in Antarctica; the crater J Herschel on the Moon; and the settlement of Herschel, Eastern Cape and the Herschel Girls' School in Cape Town, South Africa.
30.
John Herschel married Margaret Brodie Stewart on 3 March 1829 at St Marlyebone Church in London, and was father of the following children:.
31.
John Herschel died on 11 May 1871 at age 79 at Collingwood, his home near Hawkhurst in Kent.