  In a paper in Arch. Rational Mech. 214 (2014), Wen-An Yong has described the
dynamics of a compressible fluid with Maxwell delayed viscosity as a symmetric
hyperbolic system of balance laws, and shown that the solutions of this system
tend to solutions of the Navier-Stokes equations. The purpose of the present
note is to present a Galilei invariant version of Yong's model and communicate
observations on its shock waves.
