1889.] Conductors in the Neighbourhood of a Wire. 11 



A 





Fit]. 1. 



P 



M 



Ji 



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► F 



f* 



W 





A 



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The method used is shown in fig. 1. AI3, CD is the action of 

 a vibrator (shown in elevation in fig. 2) of the same shape and size 

 as the one used by Hertz in the experiments described in Wiede- 

 mann's ' Annalen,' vol. 34, p. 553, AB, CD being squares of tin-plate, 

 40 cm. square. BE, EF wires, each 30 cm. long, terminating in 

 the brightly polished balls E and F, these balls being separated by 

 an air space of 3 or 4 mm. The terminals of the induction coil are 

 fastened to BE, CF respectively. L, N are pieces of tin-plate placed 

 in front of AB and CD, having insulated wires about 25 metres long 

 fastened to them, the ends M and being covered with sealing-wax. 



The resonator (fig. 3) is, as in Hertz's experiments, a ring of wire 

 about 70 cm. in diameter, terminating in two balls, the distance 

 between which can be accurately adjusted by means of a screw. The 

 way in which the resonator was used was different from Hertz's 

 method. Two wires of equal length covered with gutta-percha and 



