35. Forbes, James David (1809-1868)
Travels through the Alps of Savoy and Other Parts of the Pennine Chain with Observations on the Phenomena of Glaciers. Edinburgh: Adam and Charles Black; London: Longman, Brown, Green, and Longmans, 1843.

A glacier table on the Mer de Glace, from James Forbes, Travels through the Alps of Savoy, 1843.

Measuring the depth of a glacial margin, from James Forbes, Travels through the Alps of Savoy, 1843.
James Forbes was professor of physics at Edinburgh University, and he met Agassiz at the Glasgow meeting of the British Association for the Advancement of Science in 1840. Intrigued by the new glacial theory, he went to Switzerland and viewed and studied the Alpine glaciers, and he became an ardent convert.
It was Forbes who first figured out how glaciers move, by a kind of viscous flow. But the significance of his book lies in the fact that it presents, in elegant visual form, virtually every aspect of the glacial theory.
Forbes did all his own sketches, and he shows us distant views of glaciers, close-up views, and views of the Alps themselves, such as the Matterhorn. He chose for his frontispiece a dramatic view of himself, perched beneath a glacier table, which is formed when an erratic block shields the ice below it from the sun.
As the surrounding area melts down, the rock is left perched on a pillar of ice. Agassiz showed us several glacier tables in his plate of the Unteraar glacier (see item 30), but they are not nearly so dramatic as this image.
