and
Kepler's laws of planetary motion.|233x233px Somerville conducted experiments to explore the relationship between light and magnetism. Her first paper, "The magnetic properties of the violet rays of the solar spectrum", was published in the
Proceedings of the Royal Society in 1826. Although her conclusions were faulty, the topic was of popular interest at the time and the paper brought her to notice in scientific circles. Sir
David Brewster, inventor of the
kaleidoscope, wrote in 1829 that Mary Somerville was "certainly the most extraordinary woman in Europe – a mathematician of the very first rank with all the gentleness of a woman".
Lord Brougham asked Somerville to translate the
Mécanique Céleste of
Pierre-Simon Laplace for the
Society for the Diffusion of Useful Knowledge. Laplace had, in five exhaustive volumes, summed up the current state of gravitational mathematics.
Mécanique Céleste was acclaimed as the greatest intellectual achievement since the
Principia. Somerville produced not just a translation, but also an expanded version of the first two volumes. She wrote a standalone exposition of the mathematics behind the workings of the
Solar System, of which she said "I translated Laplace's work from algebra into common language". It was published in 1831, under the title of
The Mechanism of the Heavens, and it immediately made her famous. Until the 1880s
Mechanism was set as a textbook for undergraduates at the University of Cambridge. The book was praised by
George Peacock, Professor of the
University of Cambridge, thus many of the 750 copies printed were bought in Cambridge. Reviews were favourable and Somerville received letters of congratulation from "many men of science". She was elected honorary member of the
Royal Irish Academy, the
Bristol Philosophical Institution, and the
Société de Physique et d'Histoire Naturelle de Genève in 1834. The British Crown granted her a civil pension of £200 a year in recognition of her eminence in science and literature. Somerville was passionate about astronomy and believed it to be the most extensive example of the connection of the physical sciences in that it combined the sciences of number and quantity, of rest and motion. In Somerville's time, the value of scientific publications depended on the currency of the information, therefore frequent editions had to be produced. Her subsequent books reflect the time that she could be free in her domestic life as her children became more independent. They also reflect the need to earn money, as the Somervilles suffered through a number of financial crises that peaked in 1835. She publicly and plausibly maintained that she wrote only for pleasure. Privately, she paid considerable attention to the profitability of her books. Through personal connections she could secure
John Murray as the publisher of her first book,
Mechanism, and he remained her publisher throughout her long career. Murray later commented that despite having made little profit he was very pleased to have had the honour of publishing the works of such an extraordinary person. Her second book,
On the Connexion of the Physical Sciences, sold 15,000 copies and established her reputation in elite science.She was among those who discussed a hypothetical planet perturbing
Uranus. In the 6th edition of
Connexion (1842), she wrote, "If after the lapse of years the tables formed from a combination of numerous observations should be still inadequate to represent the motions of Uranus, the discrepancies may reveal the existence, nay, even the mass and orbit of a body placed for ever beyond the sphere of vision". Predictions were fulfilled in 1846 with the discovery of
Neptune revolving at a distance of 3,000,000,000 miles from the Sun. "The mass of Neptune, the size and position of his orbit in space, and his periodic time, were determined from his disturbing action on Uranus before the planet itself had been seen."
Connexion ran to 10 editions, more than 9,000 copies and was its publisher's most successful science book until
The Origin of Species by
Charles Darwin.
Geographical Distribution of Plants from
Alexander Keith Johnston's 1848
The Physical Atlas. Her book
Physical Geography was published in 1848 and was the first English textbook on the subject. It remained in use until the early 20th century. Somerville followed, as she said, "the noble example of
Baron Humboldt, the patriarch of physical geography", and she took an extended view of geography that included the Earth, its animal, "vegetable inhabitants", as well as "the past and present condition of man, the origin, manners, and languages of existing nations, and the monuments of those that have been".
radiolarian.
Physical Geography starts with describing the overall structure of planet Earth, along with a brief allusion to the location of the Earth within the
Solar System. Subsequently, the book focuses on terrestrial topics, such as the most basic features of land and water, and formations such as mountains, volcanoes, oceans, rivers and lakes. Somerville goes on to discuss the elements that govern temperature, such as light, electricity, storms, the aurora and magnetism. Eventually the book turns to vegetation, birds and mammals, and their geographical distribution in the Arctic, Europe, Asia, Africa, America and the Antarctic. Somerville ends the book with a discussion of "the distribution, condition, and future prospects of the human race". She emphasises the reciprocal dependencies in physical geography and the relationship between human beings and nature. In line with
Victorian thinking, Somerville asserts the superiority of human beings, but maintains the interdependencies and interconnectedness of creation.
Physical Geography sold more copies than any of her other books and earned Humboldt's admiration. After receiving a copy of the book he wrote to her: "You alone could provide your literature with an original cosmological work". Her fourth book,
Molecular and Microscopic Science, took 10 years to write, finally published in 1869. She soon had doubts about devoting herself to popularising science, instead of concentrating on mathematics alone. Of the book she said: "In writing this book I made a great mistake, and repent it - Mathematics are the natural bent of my mind. If I had devoted myself exclusively to that study, I might probably have written something useful, as a new era had begun in that science." Regardless, the book was another success. It gave an up-to-date description of the latest discoveries revealed through the
microscope and was published in two volumes and three parts. In the first part Somerville explained the latest thinking on
atoms and
molecules, the second covered plant life, while the third explored animal life. The book included 180 illustrations, which caused her publisher great expense. Although Mary Somerville did not exhibit work at the Great Exhibition of 1851, her scientific writings were widely read during the period and contributed to the Victorian public’s growing engagement with astronomy, physics, and the physical sciences. Historians of Victorian science note that the Exhibition’s emphasis on scientific instruments, education, and the popularisation of scientific knowledge reflected themes central to Somerville’s work, particularly her books
On the Connexion of the Physical Sciences (1834) and
Physical Geography (1848). She was elected to the American Geographical and Statistical Society in 1857 and the Italian Geographical Society in 1870, and was made a member of the
American Philosophical Society. ==Death==