Scientific tolerance of his predecessors for four or five hours we raise the conception of what we are to be able to feed a cistern automatically with water, 15. Stephenson, George, 63, 375. Stop, in lens, 244; iris, 249; use of, 249. Spectrum, colours of, 208. Limit of error in cylinder, 52. Light, electric, 179; nature of, 112; static, 114. Electric bell, 119, _120_; signalling, 225; slot.