Los puntos clave no están disponibles para este artículo en este momento.
Abstract Messrs. Graham Bell and Sumner Tainter have shown that, under certain conditions, intense rays of light, if allowed to fall with periodic intermittence upon thin disks of almost every hard substance, will set up disturbances in those disks corresponding to this periodicity which result in sonorous vibrations. Mr. Bell has subsequently shown that such effects are not confined to hard substances, but that they can be produced by matter in a liquid form.
W.H. Preece (Sat,) studied this question.