14 C. A. Chant — Variation of Potential along the 



series, and the quarter-wave-length deduced from the curve 

 approximately the same as that obtained in the dispositions A, 

 B, C. 



As has been already remarked, the curves are very clearly 

 defined. The successive sets of readings agree remarkably well, 

 but yet it was impossible to get a second mimimum at a distance 

 of three-quarters of a wave-length from the end. This is not 

 what was looked for with this transmitter. One would expect 

 .the condenser circuit, with its persistent oscillations, to keep up 

 perfect standing waves in a wire in resonance with it, but with 

 no length used was this satisfactorily exhibited. 



The waves radiated from the wire, no matter what its length, 

 have the frequency of the condenser circuit, and also, to a 

 smaller degree, that of the fundamental of the wire. Over- 

 tones are scarcely noticeable. 



From my experiments it must be concluded that the earth 

 connection does not injuriously affect the form oi the oscillation 

 about the antenna ; indeed, the curves obtained with disposition 

 B are rather more uniform than those with the others. The 

 earth connection, however, assuredly has influence in other 

 ways. I believe all systems of wireless telegraphy except the 

 Braun'and the Lodge-Muirhead* join both transmitter and 

 receiver to earth ; and, according to Jackson, f severing the 

 earth connection reduced the signalling distance by 85 per 

 cent. The action of the earth must be that of guiding the 

 waves, thus allowing them to pass over obstacles such as the 

 bulging-out of the earth's surface. The explanation given by 

 Taylor;}: seems the most satisfactory. 



This explanation is very similar to that suggested by Lecher,§ 

 and to that, by Heaviside.| More recently Kopsel^T has put 

 forward the view that in Marconi's long-distance transmission 

 the earthing wire and earth capacity form a system in partial 

 if not in entire resonance with the antenna. There may have 

 been some such effect in the transatlantic experiments, but 

 such can hardly be the case in the numerous experiments by 

 other workers who find ground connection necessary to success. 



*See Nature, vol. lxviii, p. 247, July 16, 1903; N. Y. Electrical World 

 and Engineer, vol. xlii, p. 173, Aug. 1903. 



fH. B. Jackson, Proc. E. S., lxx, p. 254, 1902. 



% J. E. Taylor, Lond. Electrical Review, May, 1899. See also L. de Forest, 

 N. Y. Electrical World and Engineer, May 17, 1902 ; Prasch, Die drahtlose 

 Telegrapliie (Stuttgart, 1900), p. 65. 



(See, however, a communication on Theories in Wireless Telegraphy in N. 

 Y. El. W. & E., Oct. 31, 1903, by R. A. Fessenden.— Note added on correct- 

 ing proof.) 



SB. Lecher, Phys. Zeitschrift, iii, p. 13, 1902 ; iv, p. 320, 1903. 



I Heaviside, Electromagnetic Theory, i, § 60 ; ii, § 393. See preface to 

 vol. ii. 



TT A. Kopsel, Dingler's Polytechnisches Journal, June, 1903 ; abstracted in 

 N. Y. Electrical World and Engineer, Aug. 29, 1903. 



