| Show cheap phonograph A modification of digons phonograph is said to have been devised by a painter in milan it costs under twenty dollars and the wax cylinders are reproduced in zinc ty by the process at a cost of five cents each selling price indicating the presence of firedamp A small instrument has been devised for use in mine to indicate the presence of firedamp or in gas mains to indicate the escape of gai rhe phe invention is based upon the property certain metals have of evolving heat beat in the presence of hydrogen gas new sound recording apparatus in phonograph and similar sound recorders use Is usually made of cylinders covered with tinfoil or wax for receiving as the cylinders revolve the impression made by the scribers bers A new sound recording apparatus operates on an entirely different principle the cylinder is replaced by a flat surface which is made to oscillate and move downwards at regular intervals by special mechanism the wisest must in a thousand times be once mistaken the most foolish in a thousand times must be once right |
