Potential along a Wire transmitting Electric Waves. 



,37 



Fig-. 4. 



upon the wire, which was explored by placing the little 

 detector near it at different points in its length. 



Since the magnitude of the effect depends on the distance 

 the detector wing is held from the long wire it was necessary 

 to regulate this accurately. To do so a small glass tube 

 about -f cms. long. T, fig. 4, with bore just great enough to 

 allow it to slide over the wire, was 

 taken, and to the outside of this was 

 fastened a bit of finely-drawn tubing, 

 m, into which the wing fitted snugly. 

 In all the experiments the wing was 

 1 cm. long. 



The glass tube was attached to a 

 piece of hard rubber (or mica), M,. 

 which, again, was cemented to the 

 top, C, of a carriage which moved 



along beside the wire. 



Thus, to examine any portion of the wire, the carriage was- 

 moved along to the required place, the distance of which 

 from the end of the wire was measured by a scale on the 

 ways on which the carriage moved. The detector was mag- 

 netized, then placed in its pocket beside the glass tube, and 

 sparks made to pass at the oscillator for a certain length of 

 time. The detector was then removed and examined by the 

 magnetometer. This process was systematically carried out, 

 beginning at the end of the wire and advancing by equal 

 spaces. 



For the linear oscillator, shown in fig. 1, c, the arrange- 

 ment was precisely the same as for the cylinders. For the 

 Hertzian oscillators, fig. 1, d, a rounded end was given to- 

 one of the plates by taking a piece of brass rod 6 mm. in 

 diameter and about 2 cms. long, rounding the ends, and then 

 making a slit in one end, which allowed it to be slipped over 

 the plate. This is shown in fig. 5. 



Fiff. 6. 



The arrangement for the spherical doublet is shown in 

 fig. 6. When the coil was in action sparks passed between 



