In the mode we have described, this telegraphic system only admits of audible transmissions, and consequently cannot register messages. To supply this defect, it has been suggested to make the receiving vibrators react on registers, so arranging the latter that their electric organ may present such magnetic inertia, that, when it is influenced by the vibrations of sound, its effect may be maintained throughout the time of vibration. Experiments show that a Morse receiver, worked by the current of a local battery, will be enough for this purpose; so that if the musical vibrator is made to react as a relay, that is, on a contact in connection with the local battery and the receiver, the dots and dashes may be obtained on it which are the constituent elements of the Morse code. On these principles, and considering that the musical spaces separating the different notes of the scale are such as may be easily distinguished by the resonator, seven simultaneous transmissions may be obtained on the same wire; but experience shows that it is necessary to be content with a much smaller number. Yet this number may easily be doubled by applying the mode of transmission in an opposite direction to the system. Mr. Bell states that the idea of applying the telephone to multiple electric transmissions occurred simultaneously to M. Paul Lacour of Copenhagen, to Mr. Elisha Gray of Chicago, to Mr. Varley of London, and to Mr. Edison of New York; but there is some confusion here, for we have already seen, from reference to the patents, that Mr. Varley’s system dates from 1870, that of M. Paul Lacour from September 1874, that of Mr. Elisha Gray from February 1875, and those of Messrs. Bell and Edison were still later. Yet it appears from Mr. Gray’s specification that he was the first to conceive and execute instruments of the kind. In fact, in a specification drawn up on August 6, 1874, he distinctly put forward the system we have described, and which is the basis of those of which we have still to speak. This specification was only an addition to two others made out in April and June 1874. Mr. Varley’s system has only an indirect relation to the one we have described. It appears from what Mr. Bell said on the subject in a paper addressed to the Society of Telegraphic Engineers in London, that he himself only attaches a secondary interest to this invention.