01 n. An instrument, consisting of a tube having one end open and the other end covered with a thin flexible membrance to the center of which is …
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1.
An instrument, consisting of a tube having one end open and the other end covered with a thin flexible membrance to the center of which is attached a small mirror. It is used for exhibiting upon a screen, by means of rays reflected from the mirror, the vibratory motions caused by sounds produced at the open end of the tube, as by speaking or singing into it.(Physics)