During the summer of 1932 Professor Tilden invented a device for measuring the speed of automobiles. The Enoscope, as it was called, was introduced in several states. It consisted of a black L-shaped box with two open sides and a mirror attached across the interior angle. The operator set the scope on a fixed tripod at a measured distance to the spot the car would first pass. When the blip of the moving vehicle registered on the mirror the operator would start his stopwatch. When the car reached the operator’s position he would stop his watch. The elapsed time compared to charted time/distance relation­ships would indicate the miles per hour.