 It consists merely of an elastic membrane, such as thoroughly flexible soft sheet-rubber, tightly stretched over the mouth of a receiver of any form, into which receiver the voice is introduced by a wide-mouthed tube of convenient shape.In some cases the receiver may be dispensed with, and the membrane be stretched across the open end of the tube itself.This process would later be linked to the independent invention of research begun by Ernst Chladni, who used powder rather than liquid to facilitate the visual patterns.Watts Hughes work not only was demonstrated at a scientific meeting of the Royal Society, her scientific paper in 1891 led her to publish a 47-page book that extensively detailed how she made sound visible.