TELEGRAPHING WITHOUT WIRES.

Globe, Volume IX, Issue 1284, 1 May 1878, Page 3

TELEGRAPHING WITHOUT WIRES.

["Scientific American."] Some recent experiments by Professor Loomis, -which -will be adverted to presently, recall to our mind some of the interesting ones made years ago, serving to re-awaken interest in a matter that, although well known, had not received the attention it deserved, owing to the rapidity with which one discovery in electricity was following in the wake of another. We refer to the almost constant traversing of telegraph wires by earth currents. One of the experiments to which we refer was made by M. Bouchette on the left bank of the Rapt-de-Mad, a small stream in the Department of the Moselle. Putting to the earth the two ends of a wire 1100 feet long, he sent through it the current from a battery of two Bunsen cells. On the right bank a lino of equal length, having a galvanometer in circuit, was also put to the earth at its two ends. When the battery circuit was closed the neodle of the galvanometer was thrown violently against one of its stops ; when the current was reversed the needle flow around to the other. This showed clearly that the current which traversed the galvanometer circuit, depended entirely upon that from the battery, yet the two circuits were separated by a distance of 300 feet, including the intervening stream. The subject was taken up a little later by M. Bourbouze, who has obtained some very important results. Ho demonstrated the existence of earth currents by connecting a delicate galvanometer with the gti3 and water main of his laboratory. Ho varied his experiments by connecting the galvanometer with a body of water and with a metallic plate buried in the ground. In one of his researches it occurred to him to put one pole of a battery to the earth and to connect the other with a body of water. On pressing down his key, the galvanometer of the former circuit was at once deflected, and remained permanently so. Tho battery current was interrupted, the needle returned to Zero; tho current was rcversod, the needle swung round in the opposite direction. Tt is evident that in order to obtain good results tho earth currents must be neutralised, as they tend to increase or diminish tho deflection. This is 1 easily done. When the balance is obtained

the existence of any other current, however transient, is at onco detected. The first experiments of M. Bourbouze wero made near the Pont d'Austerlitz, Paris. One of the wires was connected with the earth and the Seine. A battery consisting of 600 cells (copper sulphate) was placed near the Pont Napoleon, one pole being to earth and the other connected with copper plates immersed in the Seine. Care having been taken to adjust the galvanometer in the former circuit, it was found that when the current was made the needle was deflected 25deg. and even 30deg. The same experiments were repeated at Pont St. Michael, near St. Denis, with like results. *

The possibility, therefore, of transmitting signals to distant points without the use of wires would seem to be conclusive ; and whatever doubts may have existed on the Bubject will be dispelled by the success that has recently attended the investigations of Professor Loomis, of Yale College. His experiments were made in the mountainous regions of West Virginia, between lofty peaks. For his purposes he used kites, a copper wire being substituted for the usual kite string. The kites were raised to a considerable height, when it was found that signals sent along one wire were transmitted by aerial currents to the second, ten miles distant. It was also discovered that continuous aerial currents exist at" this altitude capable of serving the purposes of the telegraph, except when interrupted by violent atmospheric disturbances.