E331 -- De motu fluidorum a diverso caloris gradu oriundo

(On the motion of fluids arising from different degrees of heat)

(based on Clifford A. Truesdell's introduction to Opera Omnia Series II, Volume 12)
In this paper, Euler corrects and works out the ideas that he first suggested in E225. It contains the first correct physical explanation of convection currents as the result of the slight compressibility of a heavy fluid; it also has the first attempt at a mathematical treatment. Further, it strongly suggests the theory of line integrals and Kelvin diaphragms. Euler also provides a counterexample, a furncae, for the "now common cry that the theorist should keep abreast of the latest experimental discoveries." Among the ideas that Euler considers in this paper are the following: He also considers the situation of a vessel with enough water in it with one part hotter and argues that in this case, the water in the lower portion of the vessel will "continually rise from the cold part to the hot, and contrariwise, in the higher portion will be carried down from the hot part toward the cold." Euler spends the remainder of the paper analyzing this type of flow in tubes.


According to C. G. J. Jacobi, a treatise with this title was read to the Berlin Academy on January 19, 1764.

According to the records, it was presented to the Petersburg Academy on August 23, 1764.

Publication: Documents Available:

Return to the Euler Archive