In the first two volumes of this book I dealt with those aspects of physics in which the fine structure of matter could be ignored.
I discussed gravitation, for instance, since any sphere
possessing the mass of the earth would exhibit the gravitational effect
of the earth regardless of the type of matter of which it was
composed. Furthermore, the question of the ultimate structure of the
finest particles of matter need not be considered in working out the
laws governing the gravitational interaction of bodies.