Background
John Herschel was born on March 7, 1792 in Slough, United Kingdom. He was the son of Mary Baldwin and William Herschel. He was the nephew of astronomer Caroline Herschel.
1829
John Frederick William Herschel by Alfred Edward Chalon
John Herschel, detail of pencil drawing by H.W. Pickersgill
Astronomer chemist inventor mathematician experimental photographer
John Herschel was born on March 7, 1792 in Slough, United Kingdom. He was the son of Mary Baldwin and William Herschel. He was the nephew of astronomer Caroline Herschel.
John Herschel studied shortly at Eton College and St John's College, Cambridge, graduating as Senior Wrangler in 1813. It was during his time as an undergraduate that he became friends with the mathematicians Charles Babbage and George Peacock.
John Herschel left Cambridge in 1816 and started working with his father. He took up astronomy in 1816, building a reflecting telescope with a mirror 18 inches (460 mm) in diameter, and with a 20-foot (6.1 m) focal length. Between 1821 and 1823 he re-examined, with James South, the double stars catalogued by his father.
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 Herschel's Catalogue of Nebulae. A further complementary volume was published posthumously, as the General Catalogue of 10,300 Multiple and Double Stars.
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. His views were published in an article entitled Light in 1828 and the Encyclopædia Metropolitana in 1845.
John Herschel made numerous important contributions to photography. He made improvements in photographic processes, particularly in inventing the cyanotype process, which became known as blueprint and variations, such as the chrysotype. 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. John Herschel made experiments using photosensitive emulsions of vegetable juices, called phytotypes, also known as anthotypes, and published his discoveries in the Philosophical Transactions of the Royal Society of London in 1842. He collaborated in the early 1840s with Henry Collen, portrait painter to Queen Victoria. John Herschel originally discovered the platinum process on the basis of the light sensitivity of platinum salts, later developed by William Willis. He coined the term photography in 1839. He was also the first to apply the terms negative and positive to photography.
John Herschel died on 11 May 1871 at age 79 at Collingwood, his home near Hawkhurst in Kent. On his death, he was given a national funeral and buried in Westminster Abbey.
John Herschel was one of the founders of the Royal Astronomical Society in 1820. He served as President of the Royal Astronomical Society three times: 1827-1829, 1839-1841 and 1847-1849. He 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.
John Herschel married his cousin Margaret Brodie Stewart (1810-1884) on 3 March 1829 at Edinburgh.