124 DIAMAGNETIC CURRENTS EXCITE HEAT. 



To show the force of the diamagnetic attraction, 

 experimenters commonly twist the string tightly, 

 to produce a swiftly-revolving motion, whereby 

 the suspended body is caused to rotate rapidly, 

 and is then instantaneously stopped, when it is 

 brought into a position intermediate between the 

 two poles, with the flat sides facing each pole. In 

 accordance with the law of attraction between 

 similarly-directed currents, this phenomenon ap- 

 pears to be due to the inductive excitation of 

 currents about the sides of the coins, correspond- 

 ing with those excited about the poles of the elec- 

 tro-magnet. 



To test the result of whirling bodies by force 

 between the poles of electro-magnets after being 

 thus arrested, an intelligent experimenter fixed 

 the rotated body on a spindle turned by a driving- 

 band from a pulley. He discovered that it became 

 electrically excited, like the pieces of iron rotated 

 between the poles of horse-shoe magnets, in mag- 

 neto-electric machines ; which excite the vibratory 

 movements of the electric ether, recognized as 

 electric light and heat. 



Another experimenter placed some fusible metal 

 (composed of lead, tin, and bismuth, which melts 

 at 212 of Fahr.) within a brass tube, and sub- 

 jected it to rotation between the poles of an electro- 

 magnet. Without friction, or contact, the rotated 

 brass case and its contents speedily became so 

 much excited by this rotation opposite to the 



