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



Table III. 



Method of Direct Excitation. 



Distance, in cms., of minima from free end of wire. 



Length 



of 



antenna. 



cms. 



200 

 300 

 400 

 500 

 600 



700 



800 



900 



1000 



A. With cylin- 

 der capacity. 



(60), 153 

 100 



120, 360 

 106, 280, 455 

 100, 290, (435), 



(545) 

 110, 300, (580) 



100, (300), (518), 



(650) 

 90, 310, 495 



(160). None 



B. With earth 

 connection. 



None 



None 



(120), (205). None 



(120), 215 



None 



100, 300, 500. 



None 

 (120). None 



(200). None 



(100), (220), (700?) 



C. With 

 equal wire. 



None 



None 



105. None 



(125), 198 



None 



(120). None 



None 



None 



(100). None 



D. Inductance 

 spool and earth. 



(60), 160 

 (90). None 

 80, 230, 380 

 (120), (200), (320) 

 None 



(58), (170), (280) r 

 (420). None 

 None 



(140), (320), (740). 



None 

 (100), (220). None 



though the curves show other oscillations superposed. With 

 disposition A this strong fundamental is absent, and the minima 

 present are undoubtedly due to the oscillations impressed on 

 the wire by the condenser circuit. All through this series will 

 be seen^ minimum occurring at approximately 100 cms from the 

 free end of the wire, and in many cases one or two other 

 minima spaced at approximately 200 cm: apart. The same 

 minima appear in disposition B with wire 700 cms long, and C 

 with wire 400 cms . 



The mean value of the wave-length is 4:04: cms , calculated as 

 follows : 



A. 



B. 



C. 













A 



Wire 











~2 



300 



2 



X 



100 



— 



200 oms 



400 



2 



X 



120 



= 



240 cms 





360 



— 



120 



zh 



24Qcms 



500 



2 



X 



106 



= 



212 cms 





280 



— 



106 



zz: 



jfj^cms 





455 



— 



280 



zz: 



I75 cms 



600 



2 



X 



100 



zz: 



200 cm8 





290 



— 



100 



— 



190 cms 



700 



2 



X 



110 



zz: 



99Qcms 





300 



— 



110 



= 



190 cms 



800 



2 



X 



100 



zz: 



200 cms 



900 



o 



X 



90 



ZZ: 



180 cms 





310 



— 



90 



= 



220 cm8 





495 



— 



310 



zz: 



185 oms 



700 



2 



X 



100 



= 



2 on™ s 





300 



— 



100 



zz: 



200 cms 





500 



— 



300 



zz: 



200 cm8 



400 



2 



X 



105 



= 



210 cms 



Mean 



202 ( 



