The Deluc crater.
The Copley Medal.
https://www.amazon.com/Account-New-Hygrometer-M-J-Luc/dp/1379541565/?tag=2022091-20
1773
https://www.amazon.com/Barometrical-observations-Hartz-Andrew-Society/dp/1140913999/?tag=2022091-20
1777
https://www.amazon.com/Pyrometry-Areometry-Physical-Measures-General/dp/3337382142/?tag=2022091-20
1778
https://www.amazon.com/Elementary-Treatise-Geology-Determining-Fundamental-ebook/dp/B07H2YS9G7/?tag=2022091-20
1809
https://www.amazon.com/Geological-travels-France-Switzerland-Germany/dp/B0030T2LMI/?tag=2022091-20
1813
geologist meteorologist physicist scientist
Jean-André Deluc was born on February 8, 1727, in Geneva, Republic of Geneva (now Switzerland). His father was Jacques-François Deluc, the main author of publications which refuted Mandeville as well as other writers of rationalism. His mother was Françoise Huaut.
As a student of Georges-Louis Le Sage, Deluc received an excellent education, particularly in mathematics and natural science.
Deluc took up commerce, which he combined with political activities. In 1768 he went to Paris on a successful embassy to the duke of Choiseul and in 1770 was nominated to the Council of Two Hundred. His travels widened Deluc's knowledge of landscape, but most of his early writings on natural science were based on numerous excursions to the Alps and the Jura. As was then fashionable, he gradually amassed, with the help of his brother, Guillaume Antoine, a collection of minerals and of flora and fauna. Later his nephew, Jean André Deluc, expanded this collection and took on his uncle’s role of voluminous discourser on geological topics, trying, for example, to dissuade Buckland and Murchison from accepting any theory regarding glacial action.
Deluc's commercial affairs failed in 1773 and he left Geneva, returning only once, for a few days. However, his decision to migrate to England afforded him greater opportunity for carrying out scientific research and writing, which he did for another forty-four years. In London, soon after his arrival, he was appointed reader to Queen Charlotte, a post with an income adequate to allow him ample leisure. During this period of his life Deluc undertook several tours on the Continent and lived for six years (1798-1804) in Germany, where he was a nonparticipant honorary professor of philosophy and geology at Gottingen University.
Deluc's meteorological researches were of more lasting value but were also hyperbolized by his contemporaries. He is said to have "discovered many facts of considerable importance" relating to atmospheric heat and moisture, but most of his observations had already been developed further by others. For instance, Deluc noticed the disappearance of some heat during the thawing of ice at a time when Joseph Black had already progressed to a hypothesis of latent heat. Deluc, however, probably can claim to be the originator of the theory, later proved more clearly by John Dalton, that the amount of water vapor contained in any space is independent of the density of the air or any other gaseous substance in which it is diffused.
Deluc's early meteorological interest was mainly in measuring heights by barometer, for which he published improved rules based on many experiments with hygrometers, thermometers, and barometers, and particularly on the fall in the boiling point of water with diminishing atmospheric pressure and increasing altitude. He devised a hygrometer similar to a mercury thermometer but with an ivory bulb that expanded when moistened and thus caused the mercury to descend. Humboldt compared the merits of this with Saussure's hair hygrometer: the latter proved better for measuring altitude on mountains and the former for use at sea level, but Deluc's hygrometer worked so slowly that its readings could seldom be combined with those of other instruments.
In 1809 he sent a long article to the Royal Society discussing the mode of action of the galvanic pile and showing that "in Volta’s pile, the chemical effects can be separated from the electrical." This, as a biographer in Philosophical Magazine wrote, "led that ingenious philosopher to construct a new meteorological instrument, very desirable for acquiring a knowledge of atmospherical phaenomena, and which he called the Electric column." The ideas expressed differed so much from those prevalent in London that the council of the Royal Society "deemed it inexpedient to admit them into the Transactions,"and the article was also published in Nicholson’s Journal. This "electric column" (or electroscope) consisted of numerous disks of zinc foil and of paper silvered on one side only, piled horizontally in order of zinc, silver, and paper within a glass tube and firmly screwed together. When the uppermost silver was connected by a wire with the lowest zinc disk, an electric current passed along the wire. Today, however, it is hard to see the importance to meteorology and physics of this electric column, which was later improved by Giuseppe Zamboni. It is claimed as a "very valuable discovery" by Deluc’s admirers but its principles, at least, had already been stated clearly by Volta on the Continent and probably also during his visit to England.
He died at Windsor, Berkshire, England, in 1817, after nearly 70 years of research.
Deluc was a religious man, and apart from his being involved with scientific studies, the latter years of Deluc’s life was dedicated to theological matters. He had a controversial view of geologist James Hutton, which expressed how although Deluc had never argued Hutton was an atheist; he had accused the man of his failure to properly counter atheism.
Deluc believed that the six days of the Creation were six epochs that preceded the present state of the globe, which began when cavities in the interior of the earth collapsed and lowered the sea level, thereby exposing the continents. To Deluc mountains were the remnants left upstanding when the adjacent areas had collapsed catastrophically, and the large boulders known today as glacial erratics had been blown out when great interior caverns filled with some expansible fluid had collapsed.
In 1790-1791 and later, in many letters, Deluc opposed Hutton’s ideas on present erosion, asserting, for example, that soil is not eroded because if it were there would be none left. In his Elementary Treatise on Geology (1809) he claimed rather bombastically that he could now demonstrate "the conformity of geological monuments with the sublime account of that series of the operations which took place during the Six days, or periods of time, recorded by the inspired penman." This discursive volume contains, inter alia, four of his earlier letters refuting the ideas of Hutton and Playfair. In his later geological writings Deluc occasionally proffers an astute minor observation but rarely, if ever, is the originator of a new idea.
He strenuously opposed the new chemical theory associated with Lavoisier and attempted to show in two memoirs on that theory, prefixed to his Introduction a la physique terrestre par les fluides expansibles, that meteorological phenomena strongly militate against it and in general that the hypothesis of the composition of water (the fundamental point in the theory) has maintained itself only by numerous other hypotheses which are in contradiction with known facts.
Deluc was a fellow of the Royal Society, correspondent member of the Paris Academy of Sciences, and member of several other scientific associations.
Deluc's favorite fields were geology, meteorology, and natural philosophy or theology, as one might expect of a Calvinistic Genevan who made many scientific excursions to the Alps. By nature an inveterate discourse he would write in a moderate tone on anything, including, for example, the history of the solar system before the birth of the sun. His great aim was to reconcile Genesis and geology; and his orthodoxy, versatility, prolixity, productivity, high social standing, and facility in languages earned him an exalted contemporary position.
Georges Cuvier ranked him among the first geologists of his age, whereas Zittel affirms that although Deluc was "held in high respect and favour during his lifetime, his papers have no permanent place in literature."
Georges-Louis Le Sage was a Swiss physicist and is most known for his theory of gravitation, for his invention of an electric telegraph and his anticipation of the kinetic theory of gases.
