Won't the- 'Scientific American give its opinion of the practicability-ofaspeakragte- legraph 1 How far caHla good pair of bi: make themselves heard ' through a- tube of: half inch diameter (or an inch if' it would be better 1) The advantages of such a telegraph are too numerous to mentionwhat' are the difficulties 1Savannah Journal. We know of no difculties in the way of the speaking telegraph, except the expense ,of the lines; they cannot be erected' so cheaply astelegraph wires, nor can tl.ey 'be operated so rapidly. The' eJl;treme distance 'through which twq individuals can comniupicate through a tube, we do not know, nor do we believe experiments have ever been' n:iade on a scale sufficient to test the question.' For short distances- through public' buildings they operate, well, and are in general use, but for public use they are far inferior to the electric telegraph. ' Gutta percha tubes would be the best and cheapest to use for long distances. We lire of opinion,, however, that the accous- tic telegraph is not so much employed as it might be, especially on shipboard, in prisons, hospitals, asylums, 'c.