So he imagined that the world had four dimensions of space, not three, and imagined that electromagnetism was warps and curves in that fourth dimension. Now here's the thing: when he wrote down the equations describing warps and curves in a universe with four space dimensions, not three, he found the old equations that Einstein had already derived in three dimensions -- those were for gravity -- but he found one more equation because of the one more dimension.
Så han forestille sig, at verden havde fire rumdimensioner, ikke tre, og forestillede sig, at elektromagnetisme var forvridninger og kurver i denne fjerde dimension. Nå her er det smarte: da han nedskrev ligningerne, der beskrev forvridninger og kurver i et univers med fire rumdimensioner, ikke tre, fandt han de gamle ligninger, som Einstein allerede havde udledt i tre dimensioner -- de var om tyngdekraften -- men han fandt en ligning mere på grund af den ekstra dimension.