Attempt at a theory of the friction of fluids
According to Jacobi, a treatise with the title "Tentamen theoriae de frictione solidorum" was read to the Berlin Academy on December 2, 1751. According to St. Petersburg Academy records, it was presented to that Academy on June 17, 1754.
This is an example of Euler's full grasp of the needs that a physical theory must fill. Among other things, he presents many experiments one may perform to measure the friction coefficient, as well as to test results. He finds that the friction of water in channels and that of solid bodies follow similar laws. Euler presents all of his manipulations in great detail and provides many numerical examples. He also gives a formula for the expression for the loss of head as a result of a wall of friction, under the assumption that it is proportional to the average pressure. (Based on Clifford Truesdell's introduction to Opera Omnia Series II, Volume 12.)
Original Source Citation
Novi Commentarii academiae scientiarum Petropolitanae, Volume 6, pp. 338-388.
Opera Omnia Citation
Series 2, Volume 12, pp.169-214.