Navier–Stokes equations

"The Navier-Stokes equation was rediscovered or rederived at least four times, by Cauchy in 1823, by Poisson in 1829, by Saint-Venant in 1837, and by Stokes in 1845. Each new discoverer either ignored or denigrated his predecessors' contribution. Each had his own way to justify the equation, although they all exploited the analogy between elasticity and viscous flow. Each judged differently the kind of motion and the nature of the system to which it applied. The comparison between the various derivations of this equation-or of the equations of motion of an elastic body brings forth important characteristics of mathematical physics in the period 1820-1850."