A MULTI-CHANNEL TELEVISION APPAR.ATUS 41 



larly, the amplifiers at the receiving end were the actual set used in the 

 three-color television apparatus previously described.^ 



At the receiving end, the three sets of signals were supplied to the 

 three electrodes of a special neon lamp N, shown in Fig. 5, which is 

 pro\-ided with a hydrogen valve to enable it to respond to the higher 

 frequencies. Condensing lenses L5 and Lo image the three electrodes 



Fig. 3— Sending end of three-channel television apparatus, showing sending prism 

 disc and photoelectric cells. 



at the eye, where another lens L- is placed at the eye to focus the face 

 of the disc D^. By this system, nine electrode images are formed, of 

 which three are superposed at the eye, and successive scanning holes are 

 seen illuminated by each electrode in turn. This viewing arrangement, 

 by which the image is visible to only a single eye, is adequate for an 

 experimental investigation of the multi-channel method, but some other 

 scheme would of course be needed if the method were developed into a 

 practical form. Of several schemes, mention will be made here only 

 5 Journal oj the Optical Society, February, 1930, p. 11. 



