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Eophone Company of New York.
1897 "At sea, in time of fog, the difficulty of locating sounds has been a serious matter, but now bids fair to be surmounted by the adoption of the ingenious instrument which has been named the eophone by its deviser. This instrument consists essentially of a vane A, which is mounted on a vertical rod and is exposed to the open air in as unsheltered a position as possible. On either side of this vane is a sound receiver, from which a tube leads to one of the ears of an observer located in a room below. Each convex surface of the vane A acts as a reflector to its own receiver and as a screen to the other one. The rod carrying this vane can be rotated by means of the handwheel, and in use the observer turns the vane round till the sound investigated is heard in one ear only. The motion is then reversed till the sound is heard in the other ear only, when the direction from which the said sound proceeds will be about midway between these two positions. By turning the wheel backwards and forwards, a position can rapidly be found in which the sounds received by the two ears are of equal intensity, in which case the axis of the vane points in the direction of the sound source."