Fleming J.A. | Akateeminen Kirjakauppa

HERTZIAN WAVE WIRELESS TELEGRAPHY - 1903 - immense public intkrest which has been aroused of late years in the subject of telegraphy without connecting wires T has un-doubtedly been stimulated by the achievements of Mr. Marconi in effecting communication over great distances by means of Hertzian waves. The periodicals and daily journais, which are the chief avenues through which information reaches the public, whilst eager to describe in a sensational manner these wonderful applications of electrical principles, have done little to convey an intelligible explanation of them. Hence it appeared probable that a service would be rendered by an endeavour to present an account of the present condition of electric wave telegraphy in a manner acceptable to those unversed in the advanced technicalities of the subject, but acquainted at least with the elements of electrical science. It is the purpose of these articles to attempt this task. We shall, however, limit the discussion to an account of the scientific principles underlying the operation of this particular form of wireless tele, mphy, omitting, as far as possible, references to mere questions of priority and development. The practical problem of electric wave wireless telegraphy, which has been variously called Hertzian wave telegraphy, Marconi telegraphy, or spakk telegraphy Fmhntelegraphie, is that of the pro-I duction of an effect called an electris wave or train of electric waves, which can be sent out from one place, controlled, detected at another place, and interpreted into an alphabetic code. Up to the present time, the chief part of that intercommunication has been effected by means of the Morse code, in which a group of long andshort signs form the letter or symbol. Some attempts have been made with more or less, success to work printing telegraphs and even writing or This series of articles is based on the Cantor Lectures delivered before the Society of Arts, London, in March, 1903. The lectures were attended by many of the leading British scientific men and electrical engineers, and attracted wide attention as the most complete and authoritative statement hitherto made of wireless telegraphy. In writing the articles for the Popular Science Monthly, the author has omitted advanced technicalities in order that the substance may be suitable for the general reader.-EDITOR. drawing telegraphs by Hertzian waves, but have not passed beyond the experimental stage, whilst rireless telephony by this means is still A., .....--- a dream of the future. -, P - - - - Ye We shall, in the first place, consider the transmitting arrangements and, incidentally, the nature of the effect or wave transmitted in the second place, the receiving appliances and, finally, discuss the problem of the isolation or secrecy of the intelligence conveyed between any two places. The transmitter used in Hertzian wave telegraphy consists essentially of a device for producing electric waves of a type which mill travel over the surface of the land or sea tvithout speedy dissipation, and the important element in this arrangement is the radiator, by which these waves are sent out. It vilbl e an advantage to begin by explaining the electrical action of the radiator, and then proceed to discuss the details of the transmitting appliances...