Abstract
If we have two media of different dielectric constants in contiguity, and if a line of electric force crosses the boundary, then it is well known that the conditions to be fulfilled are that the tangential component of the electric.force on either side of the boundary must be continuous, and also the normal component of the electric displacement or flux must be continuous. This involves a refraction of the line of electric force in crossing the boundary. It is bent away from or towards the normal, and if K1 and K2 are the dielectric constants and θ1 an θ2 the angles the line makes with the normal, then
This is a preview of subscription content, access via your institution
Access options
Subscribe to this journal
Receive 51 print issues and online access
$199.00 per year
only $3.90 per issue
Buy this article
- Purchase on SpringerLink
- Instant access to full article PDF
Prices may be subject to local taxes which are calculated during checkout
References
See P. Epstein, Kraftliniendiagramme für die Ausbreitung der Wellen in der drahtlosen Telegraphie bei Berücksichtigung der Bodenbeschaffenheit, Jahrbuch der Drahtlosen Telegraphie, vol. iv., p. 176, 1910. Epstein has, however, only delineated the field in the air. He ought to have indicated the nature of the field just below the surface in the sea or earth, as well as to show the refraction of the lines of force at the surface.
J. Zenneck, Ueber die Fortpflanzung ebener elektromagnetische Wellen langs ebenen Leiterflache und ihre Beziehung zur drahtlosen Telegraphie, Ann. der Physik, vol. xxiii., p. 846, 1907. This paper was freely translated, with expository notes by J. A. Fleming, entitled The Function of the Earth in Radio-telegraphy. See Engineering, June 4 and if, 1909.
See G. Marconi, Proc. Roy. Soc Lond., June 12, 1902. A note on the effect of daylight upon the propagation of electromagnetic influences over long distances.
See Ann. der phys., vol. v., p. 724, 1901.
See Sir J. J. Thomson, Conduction in Gases, p. 217, who says that air exposed to ultra-violet light may be regarded as full of extremely minute drops of water.
For a description of this bridge and method of using it, see the paper by J. A. Fleming and O. B. Duke, on the power factor and conductivity of dielectrics for alternating electric currents of telephonic frequency and at various temperatures, Journ. Inst. Elec. Engineers, 1912.
Interesting observations have been made on this matter by Admiral Sir Henry Jackson, F.R.S. See Proc. Roy. Soc., Lond., vol. lxx p. 254, 1902.
See G. Marconi on methods whereby the radiation of electric waves may be mainly confined to certain directions, etc., Proc. Roy. Soc. Lond., vol. lxxvii., p. 413, 1906.
See Dr. F. Kiebitz 's Recent Experiments on Directive Wireless Telegraphy with Earthed Antennae. The Electrician, March 8, 1912, vol. lxviii., p. 868.
Rights and permissions
About this article
Cite this article
The Scientific Theory and Out-Standing Problems of Wireless Telegraphy. . Nature 90, 291–297 (1912). https://doi.org/10.1038/090291a0
Issue Date:
DOI: https://doi.org/10.1038/090291a0
