Wire Transmitting Electric Waves. 



59 



The magnetic detector was the same as that used in the 

 other research. It had twenty pieces of iron, 0'014 cm in diam- 

 eter and l cm long, insulated from each other by paraffine, and 

 wound over with ninety turns of fine insulated wire. It was 

 mounted in the end of a glass tube, and all held on a small 

 sheet of hard rubber by means of wax. It is shown one-half 

 of natural size in fig. 2. 





vjf 



The magnetometer and telescope, as well as the method of 

 placing the detector behind the magnetometer, were as described 

 in the former paper. 



The manner of producing the oscillations along the wires is 

 shown (for the cylinders) in fig. 3. AB is a long straight 

 wire (O'T 111111 in diam.), ending at A in a small knob 6 mm in 

 diameter, which was separated from an end of one of the cylin- 

 ders by a piece of mica, M, usually 0'15 mm thick. By this 

 means the surgings on the cylinders were impressed 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 

 4 cms long, T, fig. 4, witli 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 l 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 car- 

 riage which moved alon^ beside the wire. 



