The Story of Wireless TelegraphyD. Appleton, 1904 - 207 страници |
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Страница 16
... resistance than when it is in the dark . In other words , it is a better conductor in the light than in the dark . The discovery appears to have been first made by one of Mr. Willoughby Smith's assistants ; although Siemens lighted on ...
... resistance than when it is in the dark . In other words , it is a better conductor in the light than in the dark . The discovery appears to have been first made by one of Mr. Willoughby Smith's assistants ; although Siemens lighted on ...
Страница 17
... resistance of the selenium , and the therewith associated change in the strength of the current in the telephone , could be at once detected . By shutting off the light rays at short regular inter- vals , signals could thus be ...
... resistance of the selenium , and the therewith associated change in the strength of the current in the telephone , could be at once detected . By shutting off the light rays at short regular inter- vals , signals could thus be ...
Страница 28
... resistance than the water or earth -obviously the nearer the battery the greater the chance of collecting them . I do not antici- pate the distance of twenty miles is at all too much ( with the means we can use to compen- sate it ) to ...
... resistance than the water or earth -obviously the nearer the battery the greater the chance of collecting them . I do not antici- pate the distance of twenty miles is at all too much ( with the means we can use to compen- sate it ) to ...
Страница 37
... resistances through C E and D F will be so much less than that through the water between C and D , that more of the current will WATER Z FIG . 4 . pass across the water , through the opposite wires , and recross at F , than take the ...
... resistances through C E and D F will be so much less than that through the water between C and D , that more of the current will WATER Z FIG . 4 . pass across the water , through the opposite wires , and recross at F , than take the ...
Страница 50
... on surface lines not at the same potential could be found ; and by means of a telephone of low resistance , Morse signals PROFESSOR TROWBRIDGE . 51 sent from Nova Scotia to Florida 50 THE STORY OF WIRELESS TELEGRAPHY .
... on surface lines not at the same potential could be found ; and by means of a telephone of low resistance , Morse signals PROFESSOR TROWBRIDGE . 51 sent from Nova Scotia to Florida 50 THE STORY OF WIRELESS TELEGRAPHY .
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aerial telegraphy arrangement battery boat cable Canada capacity Carlo Alberta coherer communication condenser conducted conductor connected copper wire detector diameter discharge discovery distance Dolbear earth earth-plates effect elec electromagnetic waves England exciter experiments feet fessor Flat Holm galvanometer graphy Hertz Hertzian waves induction coil instrument interrupter invention inventor investigations kilometers King of Italy Lavernock Point length Leyden jar lighthouse magnetic Mahlon Loomis Marconi mast means ments mercury meters method microphone miles Morse key obtained Orling-Armstrong oscillations parallel patent Poldhu poles possible Preece Preece's primary circuit Professor Braun receiving apparatus relay resistance sending station sensitive sent ship shore shown in Fig signals Sir Oliver Lodge Sir William spark-gap sparks Story successful surface syntony tance telephone terminal tion trans transmission tricity Trowbridge tube vertical conductor vertical wire vessels Willoughby Smith Wimereux wireless message wireless tele wireless telegraphy yards
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Страница 191 - Other Worlds than Ours ; The Plurality of Worlds Studied under the Light of Recent Scientific Researches.
Страница 102 - Here, then, is revealed the bewildering possibility of telegraphy without wires, posts, cables, or any of our present costly appliances. Granted a few reasonable postulates, the whole thing comes well within the realms of possible fulfilment.
Страница 196 - SHORT HISTORY OF NATURAL SCIENCE ; and of the Progress of Discovery from the Time of the Greeks to the Present Time.
Страница 103 - ... which will easily pass through buildings and fogs, to those long waves whose lengths are measured by tens, hundreds, and thousands of miles; secondly, more delicate receivers which will respond to wavelengths between certain defined limits and be silent to all others; thirdly, means of darting the sheaf of rays in any desired direction, whether by lenses or reflectors, by the help of which the sensitiveness of the receiver (apparently the most difficult of the problems to be solved) would not...
Страница 194 - Such an honest and thorough treatment of the subject in all its bearings that it will carry weight and be accepted as an authority in tracing the process by which the scientific method has come to be supreme in modern thought and life.
Страница 102 - Here is unfolded to us a new and astonishing world — one which it is hard to conceive should contain no possibilities of transmitting and receiving intelligence. Rays of light will not pierce through a wall, nor, as we know only too well, through a London fog. But the electrical vibrations of a yard or more in wave-length of which I have spoken will easily pierce such mediums, which to them will be transparent.
Страница 99 - ... handy they will run along it, and may be felt a long way off. If no wire exists they will spread out like sound from a bell, or light from a spark, and their intensity will decrease according to the inverse square of the distance. Maxwell and his followers well knew that there would be such waves ; they knew the rate at which they would go, they knew that they would go slower in glass and water than in air, they knew that they would curl round sharp edges, that they would be partly absorbed but...
Страница 111 - I was so discouraged at being unable to convince them of the truth of these aerial electric waves that I actually refused to write a paper on the subject until I was better prepared to demonstrate the existence of these waves ; and I continued my experiments for some years, in hopes of arriving at a perfect scientific demonstration of the existence of aerial electric waves produced by a spark from the extra currents in coils, or from frictional electricity, or from secondary coils.
Страница 192 - FGS The Story of the Mind. By Prof. J. MARK BALDWIN. The Story of Photography. By ALFRED T. STORY.
Страница 194 - ... constitutes in many ways the most instructive review that has ever been written of the evolution of human knowledge in its conflict with dogmatic belief. . . . As a contribution to the literature of liberal thought, the book is one the importance of which can not be easily overrated." — Boston Beacon. " The most valuable contribution that has yet been made to the history of the conflicts between the theologists and the scientists.