Signor Marconi, by means of his system of wireless telegraphy, has at length succeeded in transmitting the equivalent of the letter “s” from Europe to America. A glance at the work of the young inventor, however, will show that his success is not yet insured. His system--indeed, we might say all systems--of wireless telegraphy depends upon the properties of luminiferous ether--that mysterious medium that is supposed to exist in every known substance. The discharge of an electric spark produces in this ether a bubble-like wave which radiates in all directions. It is upon the reception and recording, at Newfoundland, of this wave, produced at England, that the success of Marconi’s experiment depends. Even to the ordinary mind, such a proposition presents innumerable difficulties. One of the most apparent would be the confusion arising from two sets of signals operated in the same locality. But just as we can throw all the rays of a search-light in one direction, Marconi reflects these waves of ether toward his receiving station. Perhaps one of the real drawbacks of this system would be the expense of maintaining a current of sufficient voltage to signal long distances. Nevertheless, we feel confident that, whether it be from the brain of Marconi or Tesla, or the united efforts of Orling and Armstrong, wireless telegraphy is insured to the future. The Great Tunnel We all remember with what wonder the public viewed the construction of the great suspension bridge between New York and Brooklyn. Remarkable as was that feat of engineering, a far more difficult one is now under way. It is proposed to run a continuous tunnel under the North river, New York City, and the East river, connecting the Pennsylvania Railroad in New Jersey with the Long Island Railroad at Brooklyn. It is to be eight miles long. Its chief purpose is to give trains, especially those from the West, a direct and unimpeded entrance to New York City. Beginning in the neighborhood of West Hoboken, the tunnel will penetrate the hard ridge of the Palisades, and continue with a downward incline until, under the North, or Hudson, river, it will reach a depth of one hundred feet. At Thirty-third street, in New York City, it will rise to within twenty-five feet of the surface, and at this level cross beneath Manhattan Island, where, at some central point, a large station will be erected. Proceeding, east, the tunnel will again take a dip to pass the East river, and come to light on the Brooklyn side in the neighborhood of the present terminal of the Long Island Railroad. The work of construction will begin early in the summer of 1902, and will require a period of three or four years. Its estimated cost is not less than $40,000,000. Isthmian Canal An important question which has arisen recently is the location of the future Isthmian canal. Shall it cross at Nicaragua or Panama? The House of Representatives, on January 9th, 1902, chose the former, the best reasons being: