From the electro-static reactions, so strongly produced on the submarine cables, in consequence of electric transmissions, it might be supposed that it would not be easy to hold telephonic correspondence through this kind of conductor, and, to ascertain the fact, an experiment was made on the cable between Guernsey and Dartmouth, a distance of sixty miles. Articulate speech, only a little indistinct, was, however, perfectly transmitted. Other experiments, made by Messrs. Preece and Wilmot, on an artificial submarine cable, placed in conditions analogous to those of the Atlantic cable, showed that a telephonic correspondence might be kept up at a distance of a hundred miles, although the effects of induction were apparent. At the distance of 150 miles, it was somewhat difficult to hear, and the sounds were very faint, as if some one were speaking through a thick partition. The sound diminished rapidly until the distance of 200 miles was reached, and after that it became perfectly indistinct, although singing could still be heard. It was even possible to hear through the whole length of the cable, that is, for 3,000 miles, but Mr. Preece believed this to be due to the induction of the condenser on itself: he holds, however, that singing may be heard at a much greater distance than speech, owing to the more regular succession of electric waves. Mr. Preece also made experiments on the subterranean telegraphs between Manchester and Liverpool, a distance of 30 miles, and found no difficulty in exchanging correspondence; and it was the same with the cable from Dublin to Holyhead, a distance of 67 miles. This cable had seven conducting wires, and when the telephone was connected with one of them, the sound was repeated through all the others, but in a fainter degree. When the currents of the telegraphic instruments passed through the wires, the induction was apparent, but not so great as to prevent telephonic communication. ESTABLISHMENT OF A TELEPHONIC STATION. Although the telephonic system of telegraphy is very simple, yet certain accessory arrangements are indispensable for its use. Thus, for example, an alarum call is necessary, in order to know when the exchange of correspondence is to take place, and information that the call has been heard is likewise necessary. An electric bell is therefore an indispensable addition to the telephone, and since the same circuit may be employed for both systems, if a commutator is used, it was necessary to find a mode of making the commutator act automatically, so as to maintain the simple action of the system which constitutes its principal merit. _MM. Pollard and Garnier’s System._--With this object, MM. Pollard and Garnier devised a very successful arrangement last March, which employs the weight of the instrument to act upon the commutator.