536 Lecture on a new property of Magnetism. 



and at first stands rather obliquely across. Contact will be made, 

 and we shall see whether it goes to the axial condition or not. See 

 how regularly it is progressing to its position, and it will stand at 

 last between the two poles as the piece of paper did, and it will take 

 no position but that between the poles so long as it is surrounded by 

 water, alcohol, ether, which make it take that magnetic position. I 

 now have the opportunity of raising this jar, without disturbing the 

 apparatus in any other respect. You see the things remain unchanged, 

 except that it is now in the solution of iron, and it stands as I place 

 this piece of wood. On making contact you will soon see that, 

 although it is in that heavy fluid, it is vibrating rapidly, and will 

 stand in this position. The air will take up the diamagnetic position ; 

 it will not move from it ; that is its true position in a magnetic body ; 

 so that you see the air is a magnetic body in water, and a diamagne- 

 tic in a solution of iron. Take any one body out of the list, say flint 

 glass ; it is a diamagnetic body to those above it, but magnetic to 

 those beneath it. This is settled, you cannot make a distinction ; 

 all bodies come to one category ; they proceed by degrees j and air, 

 vacuum, and all gases, are in the middle of these. 



Having given you these brief observations, I must occupy the time 

 that remains in bringing to your attention what will be the natural 

 consequence of these beautiful actions of matter. Whilst I give you 

 inanimate and inorganic bodies, it does not seem surprising to tell 

 you these things. If I come to show you that organic matter of all 

 kinds is liable to this action, it is a different thing. Here is an apple 

 which is diamagnetic. It is magnetic, speaking in a general sense, 

 subject to magnetism, but it is really a diamagnetic body. When I 

 tell you things of this nature are subject to magnetic force, and not 

 only subject to this force, but all magnets, remember all these things 

 we are dealing with are magnetically related to the earth just as 

 much as the needle on which the mariner depends for instruction in 

 his voyage on the surface of the ocean. When you reflect that these 

 are the consequences that follow, you may perceive the strong effects 

 of this power when it can act on these substances so placed as to be 

 liable to the action of the earth. It is in this view I take up a case 

 or two. Although the apple be decayed, I have no doubt, if it con- 

 tains no iron or ferruginous body, we shall find it diamagnetic. We 



