4 Professor D. E. Hughes [Feb. 29, 



slightest mechanical tremor allows molecular rotation, and conse- 

 quent loss or change of polarity ; but if I put a slight strain on this 

 bar, so as to fasten each molecule, they cannot turn with the same 

 freedom as before, and they now retain their symmetrical polarity like 

 tempered steel, even when violently hammered. {Experiment shown.) 

 We can only arrive at one conclusion from this experiment, viz. 

 that the retention of apparent magnetism is simply due to a frictional 

 resistance to rotation ; and whenever this frictional resistance is 

 reduced, as when we take off a mechanical strain, or by making the 

 bar red hot, the molecules then rotate with an almost inconceivable 

 freedom from frictional resistance. 



Conduction. 



You notice that if I place this small magnet at several inches* 

 distance from the needle, it turns in accordance with the pole pre- 

 sented. How is the influence transmitted from the magnet to the 

 needle? It is through the atmosphere and the ether, which is the 

 intervening medium. I have made a long series of researches on the 

 subject, involving new experimental methods, the results of which are 

 not yet published. One result, however, I may mention. We know 

 that iron cannot be magnetised beyond a certain maximum, which 

 we call its saturation point. It has a well-defined curve of rise to 

 saturation, agreeing completely with a curve of force produced by 

 the rotation of a bar magnet, the force of which was observed from 

 a fixed point. I have completely demonstrated by means of my 

 magnetic balance (shown in the Library') that our atmosphere, as well 

 as Crooke's vacuum, has its saturating point exactly similar in every 

 respect to that of iron : it has the same form through every degree. 

 We cannot reduce nor augment the saturating point of ether; it is 

 invariable, and equals the finest iron. We may, however, easily 

 reduce that of iron by introducing frictional resistance to the free 

 motion of its molecules. 



From consideration of the ether having its saturating point, I am 

 forced to the conclusion that it could only be explained by a similar 

 rotation of its atoms as demonstrable in iron. 



Eeflection would teach us that there cannot be two laws of mag- 

 netism, such as one of vibrations in the ether and rotations in iron. 

 We cannot have two correct theories of heat, light, or magnetism ; 

 the mode of motion in the case of magnetism being rotation, and not 

 vibration. 



Let us observe this saturation point of the atmosphere compared 

 with iron. I pass a strong current of electricity in this coil. The 

 coil is quite hot, so we are very near its saturation. I now place this 

 coil at a certain distance from the needle (8 inches) ; we have now a 

 deflection of 45° on the needle. I now introduce this iron core, exactly 

 fitting the interior previously filled by the ether and atmosphere. Its 

 force is much greater, so I gradually remove this coil to a distance, 



