Page:Popular Science Monthly Volume 89.djvu/721

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from the Guns

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��Protecting the Ears of Great

SI'KCIALISTS toll us that the noises of concussions, trains, fog horns, gun re- ports, the clash of machinery and other harsh or prolonged sounds wear a \v a \" the energ>' of the nervous sys- tem, shock by shock, causing deafness, fatigue and debility. An ear-protector, then, de- signed to modify the sound vibrations before they can be communicated to the organs of the internal ear, would seem to be a very necessary thing in some walks of life.

One which has been placed on the market recently is made of transparent material and has two soft rubber disks. One of these disks is small and thin and fits into the canal of the ear adjusting itself to any size ear. The other disk is larger and thicker and covers the orifice of the canal, preventing the protector from going in too far.

The device is a guard, not a stopper, and does not interfere with the natural circulation of air in the canal of the car. The atmospheric pressure is kept normal and sounds of moderate force enter the ear without change. Only those sounds

��Popular Scietice Montldy Shock


����The type of ear-protectoi ;

by the British Admiralty for use in

��n adopted the Navy

��which are of sufficient strength or of such charact?r as to produce shock are modihi'fl. The protector is also useful in keeping the ears free from dust and for excluding wind and water.

There are sewr- al of the ear-pro- tectors and shock absorbers on the market. The de- mand for them has been increast>d by the war, so many of the sol- diers having been deafened from the noise of explo- sions and burst- ing shells. Wher- ever there is a special demand for any article there are always special elTorts to improve on the existing models so that a person may take his choice of almost any number of kinds. The type which has been adopted recently by the British Admiralty for use in the Xav},- is shown in the photograph at the bottom of the page. The neat little box holds a pair of shock-absorbers and fits into the vest pocket as easily as a pill-box. The principle involved is the same as in the first illustration. There are two sound- stops, one in front and the other in back of a sensitive diaphragm. These effec- tually prevent any violent shock from passing on to the inner ear. The stops and the diaphragm are held in place by washers. The device can neither go in too far nor drop out of the cars accidentally.

It has been found that soldiers using these ear-protectors are stronger physicalh" and less inclined to suffer from digestive disorders on account of the better condition of the nervous system. Residents of rural districts visiting in one of our modern cities, and e\-en the long- suffering city-dweller accustomed to the noise might also value the

��The device is a guard, not a stopper, and does not interfere with the cir- culation of air in the canal of the ear


�� �