forces or mechanical principles can only be known in their relation to one another, and can only exist in their relation to one another. But, says Einstein, this relation between the mechanical forces is constant, and may be expressed by a mathematical formula: which mathematical formula may be used to equate all mechanical forces of the universe.

I hope that is not scientifically all wrong. It is what I understand of the Einstein theory. What I doubt is the equation formula. It seems to me, also, that the velocity of light through space is the deus ex machina in Einstein’s physics. Somebody will some day put salt on the tail of light as it travels through space, and then its simple velocity will split up into something complex, and the Relativity formula will fall to bits. — But I am a confirmed outsider, so I’ll hold my tongue.