James David Forbes

James David Forbes (April 20th 1809 - December 31st 1868) was a Scottish physicist mainly known nowadays for its work on the conduction of heat and the flow of the glaciers.

Biography

Forbes is born with Edinburgh. Its childhood is marked by the death of his/her mother whereas it is two years old and by the life withdrawn of his father with his children who follows. Its education is mainly made up of private lessons given by controlling his/her sisters to which some courses given by the schoolmaster of the close village are added. This disparate education, even décousu, do not prevent it from reading in secrecy, its father, fearing for his health, do not want to see it overloading work, any scientific book falling to him under the hand. His/her father wants that he studies to enter to the Barreau of Scotland while even would prefer to him to take the orders in the Église Anglican.

He enters to the Université of Edinburgh in 1825, towards the end of his first year he begins an anonymous correspondence with David Brewster, he signs all his articles “Δ”. Brewster publishes several of them in the Edinburgh Philosophical Journal of the Wernerian Society . The identity of Forbes is revealed fine 1828, date on which he is elected member of the Royal Society off Edinburgh. It definitively turns to science in 1830, one year after the death of his father and having finished his studies of rights. In 1831 the Royal Society also accepts it among its members. He travels during two years on the continent and returns in Scotland to died of John Leslie of which he had followed the courses to the university of Edinburgh. He finds himself in competition with Brewster for the post of professor released by this death. The station is granted to him to a vast majority in 1833. It occupies it until in 1859 when it becomes principal United College of the Université of St Andrews.

Work

Starting from 1836 it off publishes four series of article on heat in the Transactions the Royal Society off Edinburgh . It shows the Polarization heat by the Tourmaline, transmission through a pile of plates of Mica, and the possibility of its double polarization. This work is worth the to him Médaille Rumford in 1838. In 1843 its publication One the Transparency off the Atmosphere and the Laws off Extinction off the Sun' S Rays passing through it. is worth the royal Médaille to him.

In 1840 Forbes meets Louis Agassiz with Glasgow during a conference of the British Association, this meeting pushes it to study the problem of the movement of the glaciers. He travels several times in Suisse and Savoy where he studies the Glacier S alpine. In 1843 it publishes Travels in Alps . Of 1842 with 1851 it publishes a series of sixteen Letters one Glaciers in the Edinburgh New Philosophical Journal . Its point of view on the viscous flow of the glaciers is summarized in Illustrations off the Viscous Theory off Glaciers . The idea of a semi-fluid flow of the glaciers is initially put forward by Louis Rendu, then studied more in detail by Louis Agassiz, John Tyndall and Forbes. Forbes, with Agassiz, is mainly credited with the study of the difference in rate of flow of the glaciers in the center compared to the edges.

Forbes is also interested in the Géologie, it publishes memories on the thermal springs of the the Pyrenees, on the extinct Volcan S of the Vivarais and on the geology of Cuchullin and the hills of Eildon. Beside nearly 150 scientific articles, it publishes off Travels through the Alps Savoy and Other Parts off the Pennine Chain, with Observations one the Phenomena off Glaciers (1843); Norway and its Glaciers (1853); Occasional Papers one the Theory off Glaciers (1859); has off Turn Mont Blanc and Monte Rosa (1855) as well as an article Dissertation one the Progress off Mathematical and Physical Science in the 8th edition of the Encyclopædia Britannica .

In 1846 it studies the temperature of the Ground to different depth and in different grounds close to Edinburgh what enables him to determine the thermal Conductivité Calcaire, sandstone and Sable . At the end of its career he studies the thermal conductivity of the Fer. At the beginning of its career it had pointed that the thermal conductivity of a metal is roughly proportional to its electric Conductivité. Its experiments on iron show moreover than the conductivity of iron decreases when the temperature of metal increases. It is also the first to correctly measure the absolute thermal conductivity of a substance, i.e. the quantity of heat passing a second and by unit of area through an iron plate a thickness given and whose faces are maintained at constant temperature.

References

James David Forbes - Pioneer Scottish Glaciologist , Frank Cunningham, The Geographical Newspaper, vol. 157, No 2 (Jul., 1991), pp. 224-225
Forbes' S Life and Letters , by John Campbell Shairp, PG TAIT and A. Adams-Reilly, 1873
Professor Forbes and his Biographers , by John Tyndall, 1873
Proceedings off the Royal Society off Lodon vol. 19,1871, p i-ix, obituary

Honors

Medal Rumford of the Royal Society, 1838
royal Medal, 1843
Bakerian Reading 1842 One the Transparency off the Atmosphere and the Law off Extinction off the Solar Rays in passing through it.
Bakerian Reading, 1846, Illustrations off the Viscous Theory off Glacier Motion .

External bonds

a seismometer built by Forbes.

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