  We comment on the work of Tai L Chow, Eur. J. Phys. 18, 467 (1997). By
considering the Lagrangians which are uniquely defined only to within an
additive total time derivative of a function of co-ordinates and time the
author has tried to show that the gauge transformations which relate these
Lagrangians are canonical transformations. He has obtained the right conclusion
only by using wrong canonical equations and the entire exercise has hence
become erroneous and inconclusive. By using the definition of canonical
transformation through Poisson brackets we prove that the above gauge
transformations are canonical transformations.
