 It is not clear whether Mach offered this revised first law as a first step toward a theory that would replace Newton’s mechanics, deriving inertial effects from only relative motions, as Leibniz desired. But many other remarks made by Mach in his chapter criticizing absolute space point in this direction, and they have given birth to the Mach-heavy view, later to be christened “Mach’s Principle” by Albert  Einstein.[2]  The Mach-heavy viewpoint calls for a new mechanics that invokes only relative distances and (perhaps) their 1st and 2nd time derivatives, and thus is ‘generally relativistic’ in the sense sometimes read into Leibniz’s remarks about motion (see  absolute and relational space and motion: classical theories,  section 6). Mach wished to eliminate absolute time from physics too, so he would have wanted a proper relationist reduction of these derivatives also. The Barbour-Bertotti theories, discussed below, provide this.