Induction Coils, How to Make, Use, and Repair Them. / Including Ruhmkorff, Tesla, and Medical Coils, Roentgen Radiography, Etc. Etc.

by H. S. Norrie

It has been claimed that earthed or grounded air wires are necessary, but balls or similar "capacities" are not of service on the top of the wire. A theory has been advanced that the currents do not pass from air wire tip to air wire tip, but are conducted by the varying strata of the earth. No general confirmation is obtainable, however, and the experimental reader will find a wide field for research in this direction. Marconi, on the other hand, has accomplished much with zinc cylinders under six feet high, not grounded in any respect, indeed, and he also finds it impossible to assume a proportion between distance of effect and height of air wire. The following investigations and experiments are of interest in this connection:

At a meeting of the Institution of Electrical Engineers, in December, 1898, Dr. Oliver Lodge showed that there must be a certain relative position between the receiving and transmitting circuits.

He placed on one side of a room a box, containing a battery, bell, relay, and coherer properly connected up. On the other side he had an induction coil and pair of parallel discharger rods, with a spark gap to transmit waves across the room. When the rods of the receiver and transmitter were placed parallel to each other the receiving bell was operated; when the receiving rods of the transmitter were at right angles to those of the receiver the bell either failed to work, or weakened very considerably. He also told of an experiment made to determine the influence of different methods of grounding the apparatus. He found that when the apparatus was connected by a wire laid on the ground, there was the required response at the receiving station; but when the two stations were situated each side of a lake, and the ground wires immersed in the water, the receiving instrument failed to work. It seemed to him that the conductivity and power absorption of ether wave energy by water was too great to allow of the transmission of Hertz waves. This would seem to bear out the results obtained by Marconi in dispensing with ground wires.

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INDEX.

• A
• Acid, Chromic, [189].
• " Sulphuric, [212].
• Air pump, Geissler, [142].
• " " Simple, [141].
• " " Sprengel, [143].
• " blast, [76].
• " wire, [262].
• Amalgamation, [180].
• Assembly of coil, [22].
• Attraction, Window, 154, [163].
• Automobile coil, [40].
• Automatic burners, [170].
• Automatic burners, Adjustment, [176].
• B
• Ballistic galvanometer, [99].
• Barium platino cyanide, [238].
• Base for coil, [30].
• Bath coil, [61].
• Battery, Bichromate, [180].
• " Champion, [179].
• " Daniell, [191].
• " Dun, [187].
• " Edison-Lalande, [195].
• " Fuller, [184].
• " Gas-lighting, [179].
• " Gethins, [193].
• " Gordon, [194].
• " Gravity, [191].
• " Grenet, [180].
• " Harrison, [219].
• " Monarch, [179].
• " Morisot, [188].
• " Novelty, [182].
• " Open circuit, [178].
• " Polarization, [179].
• " Samson, [179].
• " solutions, [185], [188], [189].
• " Standard dry, [196].
• " Storage, [200].
• " Storage, to charge, [208].
• " Storage, to make, [101].
• " Storage, to seal, [215].
• " U. S. storage, [218].
• Beeswax, [95].
• Brush, Electric, [128].
• C
• Capacity of condenser, [100].
• Carbons for battery, [182].
• Cements, [97].
• Charging condenser, [110].
• Chromic acid, [189].
• Closed magnetic circuit, [6].
• Coherer, Aluminium, [251].
• " Branly, [254].
• " Carbon, [256].
• " Steel ball, [258].
• Coil, Failure to work, [49].
• " for gas engine, [37].
• " general remarks, [42].
• " in series, [32].
• " Medical, [51].
• " Oil immersed, [33].
• " Output of, [46].
• " Primary, [7].
• " Resistance, [40].
• " Secondary, [10].
• " Table of dimensions, [50].
• " Tesla, [35].
• " Testing, [44].
• " To select, [46].
• " Winding, [20].
• Condensers, Aluminium, [115].
• " Adjustable, [117].
• " Charging, [110].
• " capacity, 100, [119].
• " Discharge of, [225].
• " Glass, [101].
• " Mica, [108].
• " Oil, [116].
• " Paper, 105, [107].
• " Rolled up, [115].
• " Series, [108].
• Cone vibrator, [88].
• Contact breaker, [26].
• " " Adjustable medical, [85].
• " " Adjustable cone, [88].
• " " Dessauer, [80].
• " " Electrolytic, [77].
• " " Highspeed, [69].
• " " in vacuo, [81].
• " " Polechanging, [73].
• " " Queen, [83].
• " " Queen, large form, [84].
• " " Steel ribbon, [80].
• Contacts, Care of, [90].
• Core, [4].
• " Iron filing, [46].
• Crookes tube, [241].
• D
• Dessauer contact breaker, [80].
• Dielectric, [104].
• Discharger, [26].
• Dry cell, [196].
• Dun cell, [187].
• E
• Eddy currents, [6].
• Edison-Lalande cell, [195].
• Electric sand, [189].
• Electrode, [190].
• Electrolyte, [213].
• Electrolytic interrupter, [77].
• Ends for coil, [25].
• Extra current, [3].
• F
• Farad, [100].
• Fluoroscope, [239].
• Fluorescence, [137].
• Foucault currents, [6].
• Frauenhofer lines, [135].
• Frontispiece, Notes on, [42], [47].
• G
• Galvanometer, [99].
• Gas burners, [170].
• " engine coil, [39].
• " from water, [44].
• " lighting, [164].
• Gassiot star, [153].
• Geissler tube, [159].
• Glass, To pierce, [130].
• Gordon battery, [194].
• H
• Harrison cell, [219].
• Hertz resonator, [226].
• Hydrometer, [211].
• Hysteresis, [6].
• I
• Induction, [1].
• " Self, [8].
• Insulations, [97].
• L
• Leyden jars, [99].
• Lighting gas, [164].
• M
• Magnetic circuit, Closed, [6].
• Medical coils, [51].
• " " Care of, [62].
• Mercury contact breaker, [71].
• Mica condenser, [61].
• N
• Noise of contact breaker, [63].
• O
• Oil, Capacity of, [119].
• " Coil immersion, [33].
• " for oscillator, [260].
• " Linseed, [93].
• " Resin, [96].
• " Spark through, [95].
• Oscillator, [258].
• " Clarkes, [259].
• " Triple, [259].
• Output of coil, [46].
• P
• Paper condenser, [107].
• Paraffin, [94].
• Phosphorus tube, [239].
• Photography, X-Ray, [245].
• Pocket coil, [89].
• Polarity tests, [45].
• Pole, [190].
• Polechanging switch, [32].
• Polechanging contact breaker, [73].
• Primary coil, [7].
• Q
• Queen contact breaker, [83].
• " Crookes tube, [241].
• R
• Radiography, [245].
• Reel ends, [25].
• Resistance coils, [40].
• Resonance, Electric, [226].
• Resonator, Hertz, [226].
• Rheotome, [2].
• Roentgen Ray apparatus, [236].
• Rotating wheel, [154].
• S
• Series, Coils in, [32].
• Selection of coil, [46].
• Shellac, [96].
• Signs, Battery, [190].
• Soda, Bichromate of, [183].
• Spark, Electric, [120].
• " Choice of, [47].
• Spectroscope, [132].
• Spectrum, Solar, [132].
• Standard dry cell, [196].
• Sulphating, [215].
• Switch, Polechanging, [32].
• T
• Table of cost, [191].
• Tesla coil, [35].
• " " disruptive, [36].
• Testing polarity, [46].
• Transformer, [5].
• Tube, Insulating, [9].
• U
• U. S. storage cell, [218].
• V
• Vacuum, Adjusting, [242].
• " Choice of, [243].
• " Contact breaker, [81].
• " To procure, [141].
• " pumps, [140].
• W
• Water, Decomposition of, [44].
• Wax, [95].
• Wehnelt interrupter, [77].
• Wheel, Rotating, [154].
• Winder, Coil, [16].
• Winding coils, [20].
• " Secondary, 10, [14].
• " Sectional, [11].
• Wire for secondary coil, [24].
• " " primary coil, [9].
• Wires, Air, [262].
• Wireless telegraphy, [248].
• Wireless telegraphy circuit, [250].
• X
• X-Ray apparatus, [236].
• " Remarks, [243].
• " photographs, [246].

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BIBLIOGRAPHY

GENERAL REFERENCE

Electricity, Its Theory, Sources and Applications, by John T. Sprague. 3rd edition.