534 Lecture on a new property of Magnetism. 



When I place it thus in the arrangement, you will have the action of 

 the water itself as a magnetic body. The action will be shewn not 

 so beautifully as if I were alone, philosophising in private, but I 

 trust I shall shew it you. Now I will put it in and repeat the 

 experiment, and see what becomes of the water when submitted to 

 magnetic action, whether it is indifferent, or a substance exhibiting 

 this new and beautiful diamagnetic force. I have put it in sufficiently 

 large to be seen, or if not, the paper indicator will make it evident as 

 to whether it points or not, or whether it points equatorially, that is, 

 across the current, — or axially, that is, between the poles. We have 

 not much power in water ; therefore I must be careful that I do not 

 touch it. On contact being made I see it is acting, and will not pass 

 the axial point ; it will not point as a magnet, but swing back. On 

 again making contact, you will find that it does not 'pass the axial 

 direction, but vibrates about the line across. It is coming to rest, 

 and will finally take up its position. The two ends of that cylinder 

 of water are being repelled, and sent in opposite directions. You see 

 how beautifully and perfectly the water shews the same action as 

 the bismuth and phosphorous, pointing east and west. It is only a 

 want of time that prevents me shewing you fifty other bodies exhibit- 

 ing the same kind of action. 



Now, that you may be taken from these few general observations 

 a little deeper into the mystery of these things, I must point out the 

 condition of air especially, as in my view of things the condition 

 of air, as a natural substance, is the most important part of this kind 

 of action for us to pursue. I will now take a tube of air and place it 

 between the poles of the magnet ; it does not point either in this 

 direction or that. The glass tube, if it be at all influenced, will point 

 the one way or the other, according as it is made of plate or crown 

 glass. Crown glass (containing iron) is magnetic, and plate glass is 

 diamagnetic ; but I will give an illustration. When a glass tube 

 is taken, filled with air and sealed up, and put between the two poles, 

 I cannot perceive that there is any kind of action. But you must 

 not suppose this shuts out our observation of this action. By no 

 means ; we get action, which, strange to say, I am hardly able to 

 impress upon the minds of those who are the best prepared by 

 previous study to comprehend such phenomena, and the general 



