...there is no absolute scale of size in nature, and the small may be as important, or more so than the great.

Waves from moving sources: Adagio. Andante. Allegro moderato.

Theory is the essence of facts. Without theory scientific knowledge would be only worthy of the madhouse.

Electric and magnetic forces. May they live for ever, and never be forgot, if only to remind us that the science of electromagnetics, in spite of the abstract nature of its theory, involving quantities whose nature is entirely unknown at the present, is really and truly founded on the observations of real Newtonian forces, electric and magnetic respectively.

If it is love that makes the world go round, it is self-induction that makes electromagnetic waves go round the world.

...there is no absolute scale of size in nature, and the small may be as important, or more so than the great.

It is shocking that young people should be addling their brains over mere logical subtleties in Euclid's Elements, trying to understand the proof of one obvious fact in terms of something equally .. obvious.