Hot Air, Cold Air

A new device for receiving pictures sent by radio enlarges them to nine times their original size. Last week, in Manhattan, this device was successfully demonstrated by engineers of the Radio Corp. of America. Its basis is paper so sensitized that hot air will turn it black. A blast of hot air plays through a fine jet on the paper at the receiving end. A jet of cold air controlled by radio signals transmitting the desired picture by the usual radiograph process, modulates the hot air, producing the shading in the received picture. The advantage of magnifying photographs sent by radio: when the picture ig reduced, again to normal size, its details sharpen.