English Dictionary

opeidoscope

noun

An instrument, consisting of a tube with one end open and the other end covered with a thin flexible membrane with a mirror attached to its centre, used for exhibiting upon a screen, by means of rays reflected from the mirror, the vibratory motions caused by sounds that enter the tube.

I used an opeidoscope to observe the stars.

意味（1）

An instrument, consisting of a tube with one end open and the other end covered with a thin flexible membrane with a mirror attached to its centre, used for exhibiting upon a screen, by means of rays reflected from the mirror, the vibratory motions caused by sounds that enter the tube.

Among many experiments in transmitting speech I tried that of a conical point of iron fastened to the middle of an opeidoscope membrane, the point being attached to a fine wire in such a manner as not to interfere with its freedom of movement […]