Also, first solved Einstein's equation for the metric of a charged point mass. His closed-form solution, rediscovered by several other physicists within the next few years, is now called the Reissner–Nordström metric. Harold Horton Sheldon, invented a precision photoelectric color-scope measurement instrument, more accurate than the human eye Fred Waller, invented Cinerama, the Waller Gunnery Trainer, and patented the water ski