The phonograph lay under the very eyes of Science, and yet she did not see it. The logograph had traced all the curves of speech with ink on paper; and it only remained to impress them on a solid surface in such a manner as to regulate the vibrations of an artificial tympanum or drum. Yet no professor of acoustics thought of this, and it was left to Edison, a telegraphic inventor, to show them what was lying at their feet. Mere knowledge, uncombined in the imagination, does not bear fruit in new inventions. It is from the union of different facts that a new idea springs. A scholar is apt to be content with the acquisition of knowledge, which remains passive in his mind. An inventor seizes upon fresh facts, and combines them with the old, which thereby become nascent. Through accident or premeditation he is able by uniting scattered thoughts to add a novel instrument to a domain of science with which he has little acquaintance. Nay, the lessons of experience and the scruples of intimate knowledge sometimes deter a master from attempting what the tyro, with the audacity of genius and the hardihood of ignorance, achieves. Theorists have been known to pronounce against a promising invention which has afterwards been carried to success, and it is not improbable that if Edison had been an authority in acoustics he would never have invented the phonograph. It happened in this wise. During the spring of 1877, he was trying a device for making a telegraph message, received on one line, automatically repeat itself along another line. This he did by embossing the Morse signals on the travelling paper instead of merely inking them, and then causing the paper to pass under the point of a stylus, which, by rising and falling in the indentations, opened and closed a sending key included in the circuit of the second line. In this way the received message transmitted itself further, without the aid of a telegraphist. Edison was running the cylinder which carried the embossed paper at a high speed one day, partly, as we are told, for amusement, and partly to test the rate at which a clerk could read a message. As the speed was raised, the paper gave out a humming rhythmic sound in passing under the stylus. The separate signals of the message could no longer be distinguished by the ear, and the instrument seemed to be speaking in a language of its own, resembling 'human talk heard indistinctly.' Immediately it flashed on the inventor that if he could emboss the waves of speech upon the paper the words would be returned to him. To conceive was to execute, and it was but the work of an hour to provide a vibrating diaphragm or tympanum fitted with an indenting stylus, and adapt it to the apparatus. Paraffined paper was selected to receive the indentations, and substituted for the Morse paper on the cylinder of the machine. On speaking to the tympanum, as the cylinder was revolved, a record of the vibrations was indented on