156 



Adams — Electromagnetic Effects of 



responds to 500 revolutions of the axle. 



netic force which would 

 be produced by the motion 

 of a sphere charged to the 

 highest possible potential. 

 In many respects this seems 

 the most natural method of 

 procedure, and was adopted 

 in this experiment. The 

 * description of the appara- 

 tus employed follows. 



A hollow brass shaft, 

 AA (figs. 1 and 2), is sep- 

 arated into two portions 

 by the hard wood bar B. 

 The shaft turns in fiber 

 bearings, and the pulley and 

 belt at D, fig. 2, communi- 

 cate power from the coun- 

 tershaft FF. | The spheres 

 which carry the electric 

 charges are spun out of 

 sheet copper into hemi- 

 spheres, soldered together. 

 There are two sets of 

 spheres, 16 in each set. 

 Brass rods pass through 

 the hollow spheres, and are 

 soldered to them. These 

 brass rods are screwed into 

 collars carried on the axle. 

 The two sets of spheres 

 are thus insulated from 

 each other by the hard 

 wood bar, 8 cm in length. 

 The electricity is commu- 

 nicated to the two por- 

 tions of the axle by the cop- 

 per brushes CC, fig. 2, and 

 the spheres, beiug in con- 

 tact with the axle, thus be- 

 come charged themselves. 



The speed-counter E, fig. 

 2, is directly attached to one 

 end of the axle. The gear- 

 ing is so proportioned that 

 one revolution of the 

 crown-gear and dial I, cor- 



