530 Lecture on a new property of Magnetism. 



about to proceed to an arrangement in which I shall be able to 

 show you that which is a new characteristic of this force of matter. 

 In order to get these effects, I have to be exceedingly careful of 

 my arrangement, and I ask you to be satisfied with small results, 

 small as to the amount of action, but not small as to principle. 

 I must arrange the apparatus in such a manner that I can place 

 substances between these two magnetic poles, and must employ such 

 substances as will enable you all to see it. I must so place them as 

 to afford protection from the current of air in the room, so that 

 I may leave no deception or chance of deception on your minds in 

 reference to the phenomena that take place. I must ask you to 

 spare me a few moments while I arrange the apparatus, of the neces- 

 sity of which you will have evidence as we proceed. This is a glass 

 screen to prevent the effect of a eurrent of wind. If I put a glass 

 plate on this side, and another on that, I may be able, without hiding 

 things from your observation, to get a movement visibly induced. 

 Here are the centres on which I am about to make a lever move. 

 This is a very fine needle point, and here a long lever, and the centre 

 of motion shall be that tube. I mean to place this end free from the 

 action of the air whilst I make the centre of motion between the 

 poles. I want to bring the poles to act on the substance outside. 

 If I allow this short end of the lever to go upon that end, then all 

 will be free to move. I hope this little cylinder of bismuth is suffici- 

 ent to counterpoise that end, allowing free motion and showing a 

 new action. The very circumstance I have told you, that we are 

 now engaged in examining new phenomena for the first time in pub- 

 lic, must be an excuse for the rough arrangement before you, and 

 which is only the temporary one of a first discovery. If I take a 

 screen so as to allow the ends of the lever to be seen, you perceive it 

 is free to move away, and these being moveable poles, I can bring 

 them upon the one side or the other of the bismuth, and so submit 

 it to the power of these poles. You will soon distinguish between the 

 magnetic force and the new power that moves it by every current 

 through that arrangement. You see clearly — for I allow this pole 

 to come on this side the bismuth — that when that end of the needle 

 moves to my left, this piece of bismuth must be repelled by the pole 

 on my left. It is evident, the things being crossed, that if that 



