POCKET TELEPHONES.

Pukekohe & Waiuku Times, Volume 4, Issue 96, 15 October 1915, Page 4 (Supplement)

POCKET TELEPHONES.

It is possible that with the aid of an entirely new device, invented by a Dutch scientist, the telephone connection of the future will be merely a tiny hole in the wall, not larger than the diameter of a pencil in size, while the receiver and transmitter will be carried in one's pocket ; for in the new invention they are not larger than a watch. The thermaphone, as its inventor has named it, is much more sensitive than the usual telephone receiver, so that messages can be heard very much more clearly. A crosscontinent telephone message, with perfect relays, can be heard as easily with a thermaphone as though the speaker were in the next room. Moreover, it is much more silent. No one can hear the message except the person receiving it. The transmitter is so sensitive, also, that there is no need to speak loudly. The lower the voice the more clearly can it be heard. This would enable several telephones to be in use at the same time in a business office without creating a babel of sound. The principle of the thermaphone is simple. The magnet and diaphragm of the present telephone are replaced by a loop of exceedingly fine platinum wire within in 6mall aluminium cover pierced with minute holes. Currents passing through the wire cause changes in temperature, alternating from heat to cold with great rapidity. The consequent expansions and contractions of the surrounding air become evident as sound. There is littleto get out of order, and the cost of manufacture is less than half a crown. The thermaphone is also good for the receiving of wireless messages, and with one of these in his pocket, or, rather, in his ear, a man might walk along the street and hear constantly some" of the more powerful wireless messages from stations in the neighbourhood.