Page:Popular Science Monthly Volume 90.djvu/369

 Popular Science Monthly

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��Helping the Deaf to Hear with a New Electrical Ear

ANEW instrument to help the hearing of the deaf is so constructed that buzzing and grating sounds are entirely sifted out. The sounds received are actually increased in volume so that practically every partially deaf person can hear with its aid. The clearing of the tone is accom plished by carrying the sound- waves through the receiving mechanism in much the same way that a stream of water is sprayed out by the presence of a button in the middle of the nozzle. Hence the sound does not bound out of the instru- ment, but is carried around and thrown back on the diaphram of the microphone, after all rumblings have been lost in the steel passages correspond ing to the auditory^ canals of the normal ear.

The magnifying of the sound depends on the drum-head or sounding board which is buried in the heart of the instrument. The sound, after entering, is carried around through the sound chambers. It strikes on the curved surface of the drum-head, from which it is deflected through a perforated screen to the diaphram of the microphone. The drum-head is made in varying degrees of curvature, and of different materials and thicknesses.

The makers of the instrument have also prepared a testing system, not unlike an optician's test case, by which a physician can determine exactly, not only the proper curvature and thickness of the drum-head, but also the material of which it should be made. This varies from brass to lead, with silver, rubber and glass in the list. It has been found that the material gives the quality which is vital in getting just the pitch which will affect what sense of hearing is left. It is claimed that by careful fitting, as to form and material, in the drum-head, the deaf person can be made to hear nearly all words and sounds in their natural tone.

The new instrument is the product of the in-

��AIR 5PACE

���SOUND ENTERS

Above: The electrical ear, showing how the magnifying of the sound is accomplished by the drum-head

The transmitter is easily concealed in the clothes and the ear disk is reduced to a very small diameter

ventors who perfected the wire-tapping telephone in- strument which figured so prominently in the news a few months ago, and they have adapted to the perfection of the new ear-phone the same principles which made the "listening in" inaudible. Heretofore, electrical manipulation and tuning have been the only means of increas- ing the efificiency of the microphone, but with the new ear-phone, this electrical adjustment is aided in its work by the ingenious mechanical developments of the drum-head and the open spaces inside the instrument.

The disk that goes to the ear is reduced to a diameter of an inch and one half, and the transmitter, three inches in diam- eter, is easily concealed in the clothing.

��A New Pipe Which Is Sanitary and Nicotine-Proof

PIPE smokers are ever on the alert for a pipe which is nicotine-proof. The dis- advantage with pipes which claim to live up to this feature is that they cannot be

��cleaned readilv

��CENTER HOLE BURNS EVENLY EASY TO CLEAN

NO MOISTURE PASSES HERE PATH OF SMOKE aEAR THE CLEAN WELL

���The internal construction of the pipe, showing the cleaning well and the path the smoke takes

��They clog up with small particles of tobacco.

The pipe illustrated can be cleaned whenever the smoker wishes. Fur- thermore, nicotine can not be drawn through the stem, since the stem is disconnected, allowing all moisture to drip into an easily cleaned well.

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