TELEPHONE MARVELS.

Wairarapa Age, Volume XXXII, Issue 10074, 21 June 1910, Page 4

TELEPHONE MARVELS.

Experiments by which the heart- I beats of a person in London have been < ! heard over the telephone a hundred miles away, constitute the latest chapter in the romantic story of that marvellous instrument, By means of a special combination of srethosco^e j and telephone sound-magnifier, doctors in the Isle of Wiaiht have been able to hear tha heart-beats of a lady sitting in her home in Netting HiL Gate. It is calculated that the combination of stethoscope and telephone relay magnifies the intensity of sound some twenty times or more, co that the sound of breath- j ing has been rendered so audible that it has been heard by people in the room who were not using the telephone. It is claimed that heartbeats could be heard 500 miles away, and that the faintest human voice could be heard distinctly ever such a distance as from London to Constantinople. It is a rather curious fact that the telephone relay has so far been successfully used to magnify sounds in one direction only. That is to say, it v. ill magnify the voice of a person speaking from London to Dover, but will have no effect on the voice of the person replying. The next step will be the achieving of the two-way relay, which will magnify both ends. When the inventor of this remarkable instrument, Mr Sydney J. Brown, read a '. paper on his invention beforj the Institution of Civil Engineers, he ' stated that in the course of private experiments with the combined instruments on the human body, nothing but the breathing sounds were audible, the passage of the air through the the lungs being heard as the roar of the wind through a forest of trees.