Television was not invented by any one person. Nor did it spring into being overnight. It evolved gradually, over a long period, from the ideas of many people-each one building on the work of their predecessors. The process began in 1873, when it was accidentally discovered that the electrical resistance of' the element selenium varied in proportion to the intensity of the light shining on it. 'Scientists quickly recognized that this provided, away of 'transforming light variations' into electri6al" signals. Almost immediately a number of schemes were proposed for sending pictures by wire ( it was, of course, before radio).

One of the earliest of these schemes was patterned on the human eye Suggested by G. R. Carey in 1875, it envisioned a mosaic of selenium cells on which the picture to' be transmitted would be focused by a lens system. At the receiving end there would be a similarly arranged mosaic made up of electric lights. Each selenium cell would be connected by an individual wire to the similarly placed light in the receiving mosaic. Light falling on the selenium cell would cause the associated electric light to shine in proportion. Thus the mosaic of lights would reproduce the original picture. Had the necessary amplifiers and the right kind of lights been available, this system would have worked. But it also would have required an impractical number of connecting wires. Carey recognized this and in a second scheme proposed to "scan" the cells-transmitting the signal from each cell to its associated light, in turn over 3 single wire. If this were done fast enough the retentive image to be seen as a complete picture.