1893.] 



Electrical Interference Phenomena. 85 



with the barometric maximum in 10 districts, and follows it by 

 about one month in 9, and by about two months in 4, districts; the 

 other cases generally admitting of some explanation. 



3. In several insular seismic districts, and especially in Japan and 

 N"ew Zealand, the amplitude of the annual period is very small; and, 

 if many of the earthquakes of these districts originate beneath the 

 sea, this should be the case; for, in the course of a year, as the 

 barometric pressure changes, the sea will have time to take up its 

 equilibrium position, and thus the total pressure on the sea-bottom 

 will be unaltered. 



V. " Electrical Interference Phenomena somewhat Analogous 

 to Newton's Rings, but exhibited by Waves passing along 

 Wires of which a part differs from the rest." By EDWIN 

 H. BARTON, B.Sc., ''1851 Exhibition" Science Scholar. 

 Communicated by Professor A. W. RiiCKER, M.A., F.R.S. 

 Received May 25, 1893. 



1. In 1891 Mr. V. Bjerknes* showed how to measure the wave- 

 length and primary damping of the electrical oscillations in a 

 Hertzian primary conductor by the use of a special electrometer and 

 long parallel wires along which induced oscillations were propagated. 

 This form of Hertzian secondary conductor, in which the wires are 

 far too long to be in resonance with the primary oscillator, may, 

 hereafter in this paper, be referred to as " the long secondary " or 

 simply " the secondary." 



2. During the following session Herr von Geitlerf found that, if 

 the wires at any part of the long secondary were either 



(1) Replaced by others thicker or thinner than the normal wires, 

 or 



(2) Arranged nearer together or further apart than the normal 

 distances, 



then in any of these cases, a partial reflection of the electrical waves 

 occurred at such place of change in the wires. 



Herr von Greitler then made further observations of what occurred 

 when a condenser was attached at a single point of each wire, but did 

 not quantitatively examine the effect produced on the waves by a 

 finite length of the secondary being different from the rest. 



* ' Wiedemann's Annalen,' vol. 44, pp. 513 526, 1891, " Ueber den Zeitlichen 

 Verlauf der Schwingungen im primaren Hertz'sclien Leiter," yon V. Bjerknes aus 

 Christiania. 



t ' Wiedemann's Annalen,' vol. 49, pp. 184 195, 1893, " Ueber Keflezion elec- 

 trisclier Dralitwellen," von J. Eitter von Geitler. 



