As early as 1874 Mr. Elisha Gray was occupied with a system of musical telephone, which he wished to apply to manifold telegraphic transmissions, and the investigations which he made, in order to establish this system under the best possible conditions, gave him a glimpse of the possibility of transmitting articulate words by electricity. While carrying on his experiments on the telegraphic system, he arranged in fact, about the 15th January, 1876, a system of _speaking telephone_, and he deposited the specification and drawings in the American Patent Office, in the form of a _caveat_ or provisional specification. The deposit was made on the 14th February, 1876: on the very same day, Mr. Graham Bell also deposited, in the American Patent Office, a request for a patent in which he spoke of an instrument of the same kind, but with special application to simultaneous telegraphic transmissions by means of a telephonic apparatus; and the few words which could, in this specification, refer to a telephone with articulate sounds, applied to an instrument which, by Mr. Bell’s own admission, had not produced any satisfactory results. In Mr. Gray’s _caveat_, on the contrary, the application of the instrument to the electric transmission of speech alone is indicated, the description of the system is complete, and the drawings which accompany it are so exact, that a telephone made from them would work perfectly: this was proved by Mr. Gray himself, when, some time afterwards, he finished his instruments, which differed in no respect from the one described in Mr. Bell’s statement as worked by a battery. On these grounds Mr. Elisha Gray would certainly have obtained the patent, if the expiration of his _caveat_ had not been the result of an omission of form in the Patent Office, which, as we know, decides the priority of inventions in America. An action on the ground of this omission has lately been brought against Mr. Bell, in the Supreme Court of the American Patent Office, to set aside the patent granted to him. If Mr. Gray did not appeal before, it was because he was then wholly occupied with experiments on the system of harmonic telephone, applied to telegraphic communication, and he had no time to attend to the matter. However this may be, Mr. Bell did not begin to give serious attention to the speaking telephone until he had obtained his patent, and his efforts were soon crowned with success: a few months later, he exhibited his speaking telephone at Philadelphia, which has from that time attracted so much public attention, and which, when perfected in a practical point of view, reached Europe in the autumn of 1877 under the form we know.