go STRATIFICATION OF PART i. 



stratified column showed a tendency to rotate as a 

 whole round it. According to the theory of Ampere, 

 the polarity of a magnet is owing to a superficial current 

 of electricity perpetually circulating in a direction per- 

 pendicular to its axis ; and he also showed that currents 

 of electricity flowing in the same direction attract one 

 another, while currents flowing in opposite directions 

 repel each other. Hence, since the currents of electri- 

 city in the magnet and tube were flowing in the same 

 direction on one side of the magnet, and in opposite 

 directions on the other side, the stratified column was 

 attracted at one end and repelled at the other, so as to 

 take the form c/) , in consequence of its tendency to rotate 

 as a whole round the pole of the magnet. 



When narrow bands of tin foil wrapped round the 

 glass tube near the platinum wires were put in commu- 

 nication with the poles of the induction battery, brilliant 

 stratifications filled the whole tube between the tin 

 coatings every time the electric circuit was broken or 

 renewed ; and when the tube was placed horizontally on 

 the pole of a magnet, the stratifications no longer showed 

 a tendency to rotate as a whole, they were divided into 

 two parts tending to rotate in opposite directions ; when 

 the tube was placed between the poles of a powerful 

 electro-magnet, one half of the stratifications were 

 repelled and the other half attracted. When the tube 

 was placed on the north pole, the divided stratifications 

 arranged themselves on each side of the tube, changing 

 their respective positions when placed on the south 

 pole, but in every case each half was- concave in opposite 

 directions. 



Fig. 2 (p. 81) represents the form which the induced 

 stratified discharges assume when the vacuum tube is 

 placed on or between the poles of a powerful electro- 

 magnet the tin foil coatings C + C being attached by 

 wires to the terminals of an induction coil. 



