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28 MARINE REVIEW AND MARINE RECORD. ADVANCES IN WIRELESS TELEGRAPHY. In an address before the National Geographic Society in Washington last week Lieut. Col. Reber of the signal corps of the army gave a general survey of what has, so far, been accom- plished in wireless telegraphy. : "Tn 1809," said Col. Reber, "the chief. signal officer of the army instituted a series of experiments with a view of develop- ing a system of wireless telegraphy for military purposes. In September of that year signals were successfully exchanged. between Fire islaud and Fire island lightship, a distarce of 10 miles, which now appears very short, but marked the first suc- cessful transmission in this country. The system was so per- fected' by June of 1000 that two stations were installed in San Francisco harbor. These stations have worked uninterruptedly since their erection. At that time it was expected that similar stations could be installed at various suitable points in the Phil- ippine islands, but: the constant pressure for every available ofacer and man of the signal corps for other 'duties compelled the suspension of work on these lines. - "The difficulty of maintaining the cable between Fort St. Michael and Nome City, owing to its being constantly broken by the movement of the ice pack, and a desire to ascertain the progress in commercial development of wireless telegraphy, led the chief signal officer last spring to issue proposals to all manu- facturers of wireless apparatus for two separate installations in Alaska, one over water between Nome City and Fort St. Michael, a distance of 110 miles, and the other over land between Fort Gibbon and Bates City, about 90 miles. Queen & Co., repre- senting the Fessenden system, received the contract for the wafér line, and the American Marconi Co. that for the land system. ~ Delays of an unforeseen character retarded the com- pletion of the work until after the closed season set in, and the 'successful operation of these two systems cannot be assured until the open season of the coming year. = » "During the combined maneuvers of the army and navy along the coast of Rhode Island and Connecticut during. the early part of September, a number of wireless stations were erected by the corps, and two scout boats were equipped with apparatus of the De Forest, Marconi, and Fessenden systems. The use of wireless telelgraphy in those maneuvers demon- strated its great value as an adjunct in the protection of our coast against.surprise by an enemy's: fleet. "The navy, also, has for some time past been investigating the possibilityof varicus commercial systems before adopting any particulaf one. as a standard. It has installed one experi- mental Station at the navy yard in Washington, and another at the naval academy in Annapolis, some 38 miles away in an air line. The conditions of the intervening country make this dis: tance equivalent to working over about 150 miles of salt water. The Slaby-Afgo, Braun-Ducretet, and Rochefort systems have already been.-tried, and it is probable that other systems; such as the De Forrést, Lodge-Muirhood, and others will be experi- mented with in the near future. In spite of the claims made by some of its advocates secrecy, except by the use of a code, is impossible. It is, moreover, possible seriously to interfere with, if not entirely to prevent, the successful exchange of messages by creating intense disturbances in the ether through the dissi- pation of large quantities of energv. Syntonic working so far has not led to secrecy, but has increased the distance at which signals can be received. "The experience of the last two years has clearly shown that the proper sphere of wireless telegraphy is communication between shore and ship, and between ships at sea. Neither the cable systems nor the land lines will be supplanted by wireless telegraphy. No results over land have been obtained than can at present warrant its acceptance as a commercial means of transmission. While messages over land have been successfully exchanged up to distances of 50 and 60 miles when the atmos- pheric, local, the thermal conditions were favorable, that un- interrupted communication which is essential to commercial success has- not as yet been achieved. - "The experience of the Poldhu station of the Marconi com- pany in communicating with the Philadelphia and the Carlos Alberto has 'proved that messages transmitted by a powerful sending station can be received at a great distance under favor- able conditions, but what these conditions are is still a matter of uncertainty. During the experiments between the Carlos Al- berto and Poldhu their messages were read by Mr. Maskelyne, who had an experimental station at Parthournow, some 18 miles away, although the station. at Poldhu was endeavoring to dis- TS gitise its messages to the Carlos Alberto by superimposing upon it-a:series of dots. pues aw 6k and Table Head;-"Nova: 'Scotia. scientific interest. His sticcess can be expected, as the distance o¥el* Which" cémmitmication' is' tried is, among other things, a fditetion of the"energy radiated. If sufficient energy is radiated, under proper conditions," interchange of messages ought to' siié-- ceed. The reliabilitv of this method of communication and its pfébable speed'-will 'liave to be demonstrated before it becomes a*eommerciat possibility: As more ships and shore stations for wo "The: achievement of . Mr.°~Marceoni in obtaining signals': - aeréss-'the- Atlantic last year .gives additional interest to" his: fottheoming endeavor to exchange "messages between Poldhu_ The results will be of great [Dec. 25, wireless work are employed,-the question- of supervision of the various wireless stations in order to prevent interference be- comes of paramcunt importance to all governments and to the commercial _world.: Unless strict governmental supervision is established, competing companies may destroy the service of one ancther, and in time of war the system of communication De- tween vessels of the navy and the shore may be greatly impeded. "Mr. Maskelyne, in the London Electrician of Nov. 7 has succinctly stated the case as follows. 'No. doubt it is most in- teresting to. know that by using great power great distances may be covered. But what then! Can it be seriously proposed to erect 'thunder factories' all over the world, in order to carry on long-distance signalling? Surely not.. That would destroy the chief utility of wireless telegraphy, namely, signalling be- tween ship.and shore... A gigantic 'station,' such as Poldhu, is calculated: to.upset everv other on land or sea within a radius of 100 miles. Some day there will bea vessel in distress off Corn- wall using her wireless installation to call for help, and, because Poldhu happens to be dispensing the mixture as before, that vessel will be unable to communicate. Then there will have to be legislation suppressing those enormous installations. -- Kaiser Wilhelm,--with his usual foresight, appears to have realized the situation.. The proposed: conference is something for which the time is* absolutely 'ripe. 'It is time that the matter should be publicly thrashed out. that so-called wireless telegraphy is, properly speaking, not teleg- raphy at all. -It is merely a means of signalling, invaluable in its own special field, but which can be employed when time, place and circumstance permit.' oe "Germany and France have already taken steps to control wireless installations within their own territorial limits, and a movement is now on foot to present the entire subject to an in- ternational conference to establish a system of general regula- tion and control. » Sopa! : "Hertz's brilliant experimental proof of Maxwell's theory in 1888 made wireless telegraphy a possibility. Branly, in 1890, developed the coherer as a detector of Hertzian waves. in 1894, succeeded in exchanging signals, using a Hertz radiator and a Branly coherer. In 1895 Prof. Popoff first used the verti- cal wire in connection with a coherer and an earthed connection. This combination was not used by him, however, for wireless telegraphy, but for the purpose of graphically plotting differ- ences of atmospheric potential. Marconi, in 1896, received his first English patents after he had successfully transmitted mes- sages, using a Hertz radiator 'as a trensmitter and a vertical wire with an earthed coherer at the receiving station. But he did not until a year afterward appreciate the value of the vertical wire, when his attempts to extend the range of transmission of his ap- paratus failed for want of suitable length. In 1879 Prof. Hughes, the discoverer of the microphene ascertained that the dig¢charge Above all it is time the public realized Lodge, ° from a Leyden jar would cause the loose contact in a microphone to cohere; but at the time he was convinced that this was an effect due to magnetic induction, and not to the action of Hert- zian waves, and it was not until Blondel, in 1808, used the micro- phone as a wave-detector in wireless working. The progress in wireless telegraphy since that date is so recent that more than allusion is unnecessary. "When the vertical wire or antenna is charged by the in- duction coil to such a potential that the air insulation of the spark gap breaks down, electrical oscillations of high frequency are set up in the svstem formed by the vertical wire and the earthed terminal. These oscillations produce Hertz waves which are radiated outward from the vertical conductor. 'The antenna may be regarded as one-half of the familiar Hertz oscillator and the radiated waves as traveling over the surface of a conducting plate such as the surface of the earth or the sea. If this plate were perfectly conducting--sea water is practically so--the field of force would be similar to that of the dumbbell radiator, but cut in half by the conducting surface in the plane of symmetry. There is an intrinsic similarity in nearly all of the systems used, their differences being more those of detail in applying the theory as viewed by the various inventors. The use of wireless telegraphy has passed the experimental stage, and is now in i period of development similar to that which prevailed in the field of telephony some ten years ago. With increased knowledge of local, atmospheric. and thermal conditions that can be gained. only by practical, experience, greater certainty of uninterrupted communication will result." Maj. Arthur Murray and Capts. C. J. Bailey and G. F. Lan- ders of the artillery corps of the army have made a special. re- port to the war department in regard to the recent official trials of the submarine torpedo boats Adder and Moccasin in Little Peconic bay, which they were invited to witness, The report says that these trials are thought to be sufficient to show that this type of submarine boat has passed the experimental stage and -such boats hereafter must be taken into account as a practi-. cal arid useful element of seacoast defense. _ Active: preparations are in progress for launching the cruiser Va. Galveston at'the works of the William R. Trigg Co., Richmond,