1884.] on the Theory of Magnetism. 7 



change, although in reality the mere contact produced a commence- 

 ment of reversal. Let us vibrate them whilst together, allowing the 

 molecules greater freedom to act as they feel inclined ; and now on 

 separating we see that one strip has exactly the opposite polarity 

 to the other, both extremely strong, but the sum of which, when 

 placed together, is zero, or neutrality. {Experiment shown.) 



Let us take two extremely soft strips placed together, and mag- 

 netised whilst together. On withdrawal of the inducing force, the 

 rods are quite neutral. (Experiment shoicn.^ 



We now separate these strips, and find that one is violently 

 polarised in one direction, whilst the other is equally strong in the 

 reversed ; the sum of both being again zero. 



We might suppose that the reaction is due to having separate 

 bars. I will now demonstrate that this is not the case by magnetising 

 this large j-inch bar with a magnetising force just sufficient to render 

 the rod completely neutral when held vertically or under the earth's 

 magnetic influence. [Experiment shoion.) 



You notice that it is absolutely neutral, all parts as well as the 

 ends showing not the slightest trace of polarisation. I reverse this 

 bar, and you perceive that it is now intensely polarised. This is due 

 to the fact that the earth's influence uncovers or reverses the 

 outside molecules, and consequently they are now of the same polarity 

 as its interior. Upon reversing this rod, the magnetism again dis- 

 appears, and re-appears if turned as previously. We have thus a 

 rod which appears intensely magnetic when one of its ends is lower- 

 most, whilst if that same end is turned upwards all traces of mag- 

 netism disap23ear. These and several other demonstrations which I 

 shall now show you (proving the enormous influence which thickness 

 of a bar has in the production of neutrality or its retention of mag- 

 netism) are simple lecture demonstrations. For the complete proof of 

 my discovery of neutral curves I must refer you to my forthcoming 

 paper upon this subject. {Experiments shown proving the great influence 

 of a thickness of a har upon its retentive and neutral powers.) 



Inertia. 



I have remarked in my researches that the molecules have true 

 inertia, that they resist being put in motion, and if put in motion will 

 vanquish an opposing resistance by their simple momentum. To 

 illustrate this, I take this large J-inch bar, magnetise it so that 

 its south pole is at the lowest end. We know that the earth's 

 influence is to make the lower end north. I now gently strike it with 

 a wooden mallet, and the rod immediately falls to zero. I continue 

 these blows, but the rod obstinately refuses to pass the neutral line to 

 become north, the reason being in so doing it would have to change 

 the whole internal reversed curve that I have discovered. It requires 

 now extremely violent and repeated blows from the mallet to make it 

 obey the earth's influence. 



