  Planck's constant was introduced as a fundamental scale in the early history
of quantum mechanics. We find a modern approach where Planck's constant is
absent: it is unobservable except as a constant of human convention. Despite
long reference to experiment, review shows that Planck's constant cannot be
obtained from the data of Ryberg, Davisson and Germer, Compton, or that used by
Planck himself. In the new approach Planck's constant is tied to macroscopic
conventions of Newtonian origin, which are dispensable. The precision of other
fundamental constants is substantially improved by eliminating Planck's
constant. The electron mass is determined about 67 times more precisely, and
the unit of electric charge determined 139 times more precisely. Improvement in
the experimental value of the fine structure constant allows new types of
experiment to be compared towards finding "new physics." The long-standing goal
of eliminating reliance on the artifact known as the International Prototype
Kilogram can be accomplished to assist progress in fundamental physics.
