1892 __ Longrange radio signaling
‣ Comment : William Crookes optimistically reviews the potential of longrange radio signaling, a very advanced idea when this article appeared, because at the time no one could transmit and receive the signals farther than a few hundred meters. The two main experimenters reviewed are Heinrich Hertz of Germany, and Oliver Lodge of Britain. But there is also an allusion to an earlier, unnamed individual, as Crookes notes that "some years ago I assisted at experiments where messages were transmitted from one part of a house to another without an intervening wire by almost the identical means here described". This third experimenter was later identified as British Professor David E. Hughes, who had performed the experiments beginning in 1879. Because of the distances involved, it is very likely that Hughes' transmissions were the result of radio waves. Unfortunately, he was discouraged from following up on his initial work -- thus it fell to Hertz to conclusively prove the existence of electro-magnetic radiation in 1887. This article also speculated about other areas of electrical research, including the suggestion that "Another point at which the practical electrician should aim is nothing less than the control of the weather", and wondering, with respect to England, "Shall we ever be able, not to reduce our rainfall in quantity, but to concentrate it on a smaller number of days, so as to be freed from a perennial drizzle?". (Thomas H. White, “Articles and extracts about early radio and related technologies, concentrating on the United States in the period from 1897 to 1927”)
‣ French comment : William Crookes évoque la continuité du spectre électromagnétique et la possibilité d'utiliser certains rayonnements pour transmettre des messages ("possibilities for transmitting intelligence"). Jusqu'alors, les expériences avaient pour objet de vérifier la validité des équations de Maxwell. Crookes suggère une application de la transmission sans fil à distance: « Deux amis installés dans la zone de réception de leurs appareils récepteurs, étant au préalable convenus d'une longueur d'onde particulière et ayant accordé leurs instruments respectifs pour une réception réciproque pourraient ainsi communiquer aussi longtemps et aussi souvent qu'ils le voudraient en prenant le temps de produire les longues et les brèves du code Morse ordinaire? ». (W. Crookes, "Some possibilities of Electricity" 1892, “Fortnightly Review” February 1, 1892, Commentaires de H.G.J. Aitken in "Syntony and spark" pp. 112sq. 1985)
‣ Original excerpt : « Any two friends living within the radius of sensibility of their receiving instruments, having first decided on their special wave length and attuned their respective instruments to mutual receptivity, could thus communicate as long and as often as they pleased by timing the impulses to produce long and short intervals on the ordinary Morse code. At first sight an objection to this plan would be its want of secrecy. Assuming that the correspondents were a mile apart the transmitter would send out the waves in all directions, filling a sphere a mile in radius, and it would therefore be possible for any one living within a mile of the sender to receive the communication. This could be got over in two ways. If the exact position of both sending and receiving instruments were accurately known, the rays could be concentrated with more or less exactness on the receiver. If, however, the sender and receiver were moving about, so that the lens device could not be adopted, the correspondents must attune their instruments to a definite wavelength, say, for example, 50 yards. I assume here that the progress of discovery would give instruments capable of adjustment by turning a screw or altering the length of a wire, so as to become receptive of wavelengths of any preconcerted length. Thus, when adjusted to 50 yards, the transmitter might emit, and the receiver respond to, rays varying between 45 and 55 yards, and be silent to all others. Considering that there would be the whole range of waves to choose from, varying from a few feet to several thousand miles, there would be sufficient secrecy ; for curiosity the most inveterate would surely recoil from the task of passing in review all the millions of possible wave-lengths on the remote chance of ultimately hitting on the particular wave-length employed by his friends whose correspondence he wished to tap. By "coding" the message even this remote chance of surreptitious straying could be obviated. This is no mere dream of a visionary philosopher. All the requisites needed to bring it within the grasp of daily life are well within the possibilities of discovery, and are so reasonable and so clearly in the path of researches which are now being actively prosecuted in every capital of Europe that we may any day expect to hear that they have emerged from the realms of speculation into those of sober fact. Even now, indeed, telegraphing without wires is possible within a restricted radius of a few hundred yards, and some years ago I assisted at experiments where messages were transmitted from one part of a house to another without an intervening wire by almost the identical means here described. »
‣ Source : Ledos, J-J. (1996), "1996 CENTENAIRE DE LA RADIO ?", Article publié in "CAHIERS D'HISTOIRE DE LA RADIODIFFUSION", n° 49, Juin-Août 1996.
‣ Source : Crookes, William (1892), "Some possibilities of Electricity", “Fortnightly Review” February 1, 1892, pp. 174-176.
‣ Urls : http://web.chr.free.fr/info/detail.php?SID=955866757&ID=60 (last visited ) http://earlyradiohistory.us/1892fort.htm (last visited )
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