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Heap's topophone.

Invented by Lieutenant Colonel David Porter Heap of the United States Lighthouse Service, the Topophone (from the Greek 'topos' = place and 'phone' = sound) is designed to assist the ear in determining the direction from which a sound originates. Two curved metal funnels in opposition with each other at the end of a long wooden rod. Small openings at the ends of the funnels and 3.5 inch wide openings at the receptor portion of the funnels. The rod can be folded and there is a suspension ring that allows the user to wear the device and one that protrudes when the device is folded to hold in place.

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