FIG. LIST OF ILLUSTRATIONS. 1. Circuit of Discharge of a Leyden Jar, 2 Curves showing Aperiodic Discharges, 3. Curves showing Damped Sinonical Vibrations, 4. Braun's Closed Oscillation Circuit, 5. The Hertz Oscillator, 6. Marconi Transmitter, 7. Rod Conductor for Electrical Vibrations, 8. Braun's Direct Coupling, . 9. Braun's Indirect Coupling, 10. Secondary System with Symmetrical Attachments, 11. Correct Relative Position of Coupled Systems, PAGE 4 8 9 10 11 12 15 15 17 18 12. Incorrect Relative Position of Coupled Systems, 18 13. Symmetry Wire supplemented by Metal Plate, . 18 14. Arrangement of Coherer,. 20 15. Arrangement of Receiving Instrument, with Coherer, Relay, Morse, 30. Measuring the Frequency of the Primary Condenser Circuit, 31. Measuring the Individual Oscillation of the Secondary System, 32. Slaby's Measuring Rod, 33. Mounting a Complete Station, 34. A Baltic Station, . 54 56 57 57 59 60 61 64 65 42. Discharger (Multiplex Spark-gap), 41. Morse Key, with Automatic Minimum Current Cut-out, 43. Multiplex Discharger for Fixed Stations, 44. Excitation Circuit in Coupled Senders (type for use on board ship), 45. Excitation Circuit (for portable stations), 46. Method of Mounting the Sender in Portable Stations, 71 72 72 73 74 75 62. Receiving Apparatus, 55. Receiver with Schloemilch Detector and Morse Register, 58. Marconi Detector,. 59. Lodge-Muirhead Coherer, 60. Specimen of Script with a Lodge-Muirhead Coherer, 61. Receiving Apparatus, 63. Light Receiving Apparatus for Portable Stations, 83 84 85 85 88 89 90 91 92 92 64. Receiving Apparatus for use on board Ship, 93 65. Receiving Transformer for Close Coupling, 94 66. The Mounting in the Receiver for Close Coupling, 95 67. Receiving Oscillation Circuits with Loose Coupling, 96 68. Mounting for Multiplex Telegraphy as used at the Baltic Stations, 69. Wireless Telegraph Station, 73. Portable Wireless Telegraphy Station (power waggon),. 105 74. Portable Wireless Telegraphy (apparatus waggon), 75. Portable Wireless Telegraphy Station on the March, OF THE UNIVERSITY OF CALIFORNIA WIRELESS TELEGRAPHY. CHAPTER I. INTRODUCTION. THE historical development of wireless telegraphy may be summarised briefly. Every physicist knows that the scientific foundations were already most widely laid. Michael Faraday's original and ingenious ideas of interpreting the action of forces at a distance broke the ice, and, transplanted into the brain of a Clerk Maxwell, generated that undying masterpiece, the electromagnetic theory of light. Rays of light, radiant heat, and rays of electrical energy, must be thoroughly identical in character, differing merely in the dimensions of their wave lengths: they must all be based upon electromagnetic oscillations in the all-penetrating universal ether, in which they spread at the same enormous velocity of 186,000 miles per second. Equally ingenious with the theory was the longdelayed proof advanced by Heinrich Hertz with his renowned investigations into the propagation of electrical energy. Besides, the laws of oscillating discharges for the generation of periodic electromagnetic vibrations were known through the labours of Helmholtz, William Thomson (Lord Kelvin), and Gustav Kirchhoff, and had been verified in all their details by that rarely-endowed experimenter Feddersen. The experimental conditions with which they worked, however, were not adapted for action at a distance, this being first accomplished by the special form of Hertz's arrangements. The uniform subjection of all radiant phenomena to the same laws then became clearly apparent, and we learned how to guide the mechanism of the ether at pleasure and to detect the results of its action at distant stations. Signalling, by means of electrical waves, through the free universal ether was made possible, and wireless telegraphy was born. If it be |