MESSRS. EDITORS.—I have been waiting for some explanation of the cause of Prof. Morse's resignation of the office of '; Electrician to the Atlantic Telegraph Company," but nothing has yet appeared. No reason for this has yet been published, although it seetns Prof. Morse discovered that, when the cable was being paid out, before it was broken, the electric current grew feebler and feebler. This fact, although somewhat indefinitely stated, affords some data for inferring that the enterprise will prove a failure. When experiments wore made in England to send the electric current through the cable, they were stated to have been successful, but the conditions of that success did not afford data to predict tho favorable working of the cable in. the ocean. The cable experimented with was confined in a comparatively small compass, in a coil, and if a secondary current were excited in any of the conductors, it may have been conveyed so as to assist the primary current. A powerful magnetic action will be evinced in a small circuit, in which the current passes through a fine wire, many miles in length, surrounding an electro magnet; but the same will be very feeble in its effects, if sent through the fine wire of the magnet, extending lengthwise through space, instead of being wrapt in a coil. The same reasoning will apply to the cable tested in a coil at Liverpool, and when laid in the bed of the ocean. In the first case, the current should be strong ; in the second, feeble. As the capacity of a conducting wire is according to the solid section, it appears to me that the wires of the cable are too small and with the powerful battery which must be employed, they will be liable to fusion. I make these suggestions so that proper experiments may be made with the cable before the next expedition starts. Instead of being placed in a continuous coil, the cable should be laid crosswise, like the figure 8, to experiment on the influence of secondary currents ; because the cable might get crossed and twisted in the ocean and rendered useless. S. lvTew York, March, 1858.