His inventive faculties now getting full play, he took out over fifty patents in connection with improvements in telegraphy, including the duplex, quadruplex, and sextuplex system; the carbon telephone transmitter; microtasimeter; aerophone, for amplifying sound; the megaphone, for magnifying sound. Thence also emanated his phonograph, a form of telephone, and various practical adaptations of the electric light. His kinetoscope (1894) is a development of the Zoetrope, in which the continuous picture is obtained from a swift succession of instantaneous photographs (taken 46 or more in a second), and printed on a strip of celluloid. Of late he has devoted himself to improving metallurgic methods. He has taken out some 500 patents, and founded many companies at home and in Europe. Following up some of his telegraphic inventions, he had developed a machine which, by reason of the indentations made on paper, would transfer a message in Morse characters from one circuit to another automatically, through the agency of a tracing-point connected with a circuit-closing device. Upon revolving with rapidity the cylinder that carried the indented or embossed paper Mr Edison found that the indentations could be reproduced with immense rapidity through the vibration of the tracing-point. He at once saw that he could vibrate a diaphragm by the sound-waves of the voice, and, by means of a stylus attached to the diaphragm, make them record themselves upon an impressible substance placed on the revolving cylinder. The record being made thus, the diaphragm would, when the stylus again traversed the cylinder, be thrown into the same vibrations as before, and the actual reproduction of human speech, or any other sound, would be the result. The invention thought out in this manner was at once tried, with paraffined paper as the receiving material, and afterwards with tinfoil, the experiment proving a remarkable success, despite the crudity of the apparatus. In 1878 Mr Edison made a number of phonographs, which were exhibited in America and Europe, and attracted universal attention. The records were made in these on soft tinfoil sheets fastened around metal cylinders. For a while Mr Edison was compelled to suspend work on this invention, but soon returned to it and worked out the machine as it exists practically to-day. It occupies about the same space as a hand sewing-machine. A light tube of wax to slide on and off the cylinder is substituted for the tinfoil, which had been wrapped round it, and the indenting stylus is replaced by a minute engraving point. Under the varying pressure of the sound-waves, this point or knife cuts into the tube almost imperceptibly, the wax chiselled away wreathing off in very fine spirals before the edge of the little blade, as the cylinder travels under it. Each cylinder will receive about a thousand words. In the improved machine Mr Edison at first employed two diaphragms in