Mar 072021

Today is the birthday (1792) of John Herschel, the son of Mary Baldwin and astronomer William Herschel  and nephew of astronomer Caroline Herschel. He studied briefly at Eton College (down the road from Slough where he was born), and at St John’s College, Cambridge where he graduated as Senior Wrangler (top mathematics undergraduate) in 1813. It was during his time as an undergraduate that he became friends with the mathematicians Charles Babbage and George Peacock. He left Cambridge in 1816 and started working with his father, 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. He was one of the founders of the Royal Astronomical Society in 1820. For his work with his father, he was presented with the Gold Medal of the Royal Astronomical Society in 1826 (which he won again in 1836), and with the Lalande Medal of the French Academy of Sciences in 1825, while in 1821 the Royal Society bestowed upon him the Copley Medal for his mathematical contributions to their Transactions. Herschel was made a Knight of the Royal Guelphic Order in 1831.

Herschel’s A preliminary discourse on the study of natural philosophy, published early in 1831 as part of Dionysius Lardner’s Cabinet cyclopædia, set out methods of scientific investigation with an orderly relationship between observation and theorizing. He 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. This became an authoritative statement with wide influence on science, particularly at the University of Cambridge where it inspired the student Charles Darwin with “a burning zeal” to contribute to this work.

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.

Herschel and his wife traveled to South Africa in 1833 to catalogue the stars, nebulae, and other objects of the southern skies. This was to be a completion as well as extension of the survey of the northern heavens undertaken initially by his father William Herschel. He arrived in Cape Town on 15 January 1834 and set up a private 21 ft (6.4 m) telescope at Feldhausen at Claremont, a suburb of Cape Town. Amongst his other observations during this time was the return of Comet Halley. Herschel collaborated with Thomas Maclear, the Astronomer Royal at the Cape of Good Hope and the members of the two families became close friends. During this time, he also witnessed the Great Eruption of Eta Carinae (December 1837).

In addition to his astronomical work, however, this voyage also gave Herschel an escape from the pressures under which he found himself in London, where he was one of the most sought-after of all scientists. While in southern Africa, he engaged in a broad variety of scientific pursuits free from a sense of strong obligations to a larger scientific community. It was, he later recalled, probably the happiest time in his life.

In an extraordinary departure from astronomy, 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. Herschel used a camera lucida to obtain accurate outlines of the specimens and gave over the artistic details to his wife. Even though their portfolio had been intended as a personal record, and despite the lack of floral dissections in the paintings, their accurate rendition makes them more valuable than many contemporary collections.

Herschel, at the same time, read widely. Intrigued by the ideas of gradual formation of landscapes set out in Charles Lyell’s Principles of Geology, he wrote to Lyell on 20 February 1836 praising the book as a work that would bring “a complete revolution in [its] subject, by altering entirely the point of view in which it must thenceforward be contemplated” and opening a way for bold speculation on “that mystery of mysteries, the replacement of extinct species by others.” Herschel himself thought catastrophic extinction and renewal “an inadequate conception of the Creator” and by analogy with other intermediate causes, “the origination of fresh species, could it ever come under our cognizance, would be found to be a natural in contradistinction to a miraculous process.

Taking a gradualist view of development and referring to evolutionary descent from a proto-language, Herschel commented:

Words are to the Anthropologist what rolled pebbles are to the Geologist – battered relics of past ages often containing within them indelible records capable of intelligent interpretation – and when we see what amount of change 2000 years has been able to produce in the languages of Greece & Italy or 1000 in those of Germany France & Spain we naturally begin to ask how long a period must have lapsed since the Chinese, the Hebrew, the Delaware & the Malesass [Malagasy] had a point in common with the German & Italian & each other – Time! Time! Time! – we must not impugn the Scripture Chronology, but we must interpret it in accordance with whatever shall appear on fair enquiry to be the truth for there cannot be two truths. And really there is scope enough: for the lives of the Patriarchs may as reasonably be extended to 5000 or 50000 years apiece as the days of Creation to as many thousand millions of years.

The document was circulated, and Charles Babbage incorporated extracts in his ninth and unofficial Bridgewater Treatise, which postulated laws set up by a divine programmer. When HMS Beagle called at Cape Town, Captain Robert FitzRoy and the budding naturalist Charles Darwin visited Herschel on 3 June 1836. Later on, Darwin would be influenced by Herschel’s writings in developing his theory advanced in The Origin of Species. In the opening lines of that work, Darwin writes that his intent is “to throw some light on the origin of species – that mystery of mysteries, as it has been called by one of our greatest philosophers,” referring to Herschel. However, Herschel ultimately rejected the theory of natural selection.

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. In this publication he proposed the names still used today for the seven then-known satellites of Saturn: Mimas, Enceladus, Tethys, Dione, Rhea, Titan, and Iapetus. In the same year, Herschel received his second Copley Medal from the Royal Society for this work. A few years later, in 1852, he proposed the names still used today for the four then-known satellites of Uranus: Ariel, Umbriel, Titania, and Oberon . A stone obelisk, erected in 1842 and now in the grounds of The Grove Primary School, marks the site where his 20-ft reflector once stood.

Herschel made numerous important contributions to photography. He made improvements in photographic processes, particularly in inventing the cyanotype process, which became known as blueprints, 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. 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. Herschel originally discovered the platinum process on the basis of the light sensitivity of platinum salts, later developed by William Willis. Herschel coined the term photography in 1839. Herschel was also the first to apply the terms negative and positive to photography. 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” (“hypo”) could be used as a photographic fixer, to “fix” pictures and make them permanent, after experimentally applying it in this way in early 1839.

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.

Slough, home of William Herschel’s observatory and John’s birthplace, is not, nor ever has been, the epicenter of English cuisine.  But . . . the Horlicks factory used to be a well-known landmark as seen from the railway passing through Slough, although I am given to understand that it is under demolition at this point.  Shame.  Horlicks was my bedtime hot drink through much of my boyhood.  If you can still get it, a cup of Horlicks might make a Slough-themed recipe for today.  Or . . . you might try one of the recipes found on their website:

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