518 Proceedings. 



remain in full activity ; the combination is not statical, but dynamic, and if 

 stable is so only because the forces are momentarily in equilibrium. 



magnetism 

 difficulty 



the idea which, when propounded by Faraday some thirty years ago, seemed 

 so difficult and perplexing to most minds. 



"When the operator in the telegraph office presses the knob of his break 

 circuit key, perhaps 100 or more times in a minute, what happens by which 

 the signal is conveyed perhaps many hundreds of miles off? Why, that every 

 molecule in that prodigiously long wire swings to the touch, and reverses its 

 vibrations as often as the circuit is completed and broken. While the notion 

 was yet fresh in men's minds that a mass of matter, as a stone or a piece of 

 metal, was quite inert, its parts in a condition of stable equilibrium, the 

 conception of such free molecular motion as would allow each particle to change 

 its positive for its negative pole every time the direction of the current 

 through it was reversed, seemed indeed incredible. Again, crystallization 

 was held, in the older books, to imply necessarily that the crystalline matter 

 had passed into that condition from a liquid condition, because in that 

 condition only could it then be conceived that motion or action among the 

 molecules could take place ; and the very practical fact that iron that had 

 certainly once been fibrous in structure had become crystalline while actually 



as a railway axle, or in some position subject to great strains and 

 vibrations, seemed to involve inexplicable difficulties. But now that the idea 

 of statical equilibrium is well nigh obsolete, that the dynamic theory of heat 



in use, 



recocnised 



ever vibrating in obedience to unvarying laws, but with ever-varying 

 velocity, and in waves of constantly changing amplitudes and rapidity, and 

 with force before which all the power which man can wield is absolutely 



in a word, that all nature is alive and not dead — then, though 



msi 



the wonder is increased, the power of conceiving it is vastly expanded, and 

 phenomena which appeared incredible and inconceivable when isolated 

 become comparatively simple and luminous when they form part of an 

 universal and connected system. It would be quite out of place for me to go 

 into the details of the experiments of Dr. Joule, and the many others who 

 have followed him, in determining the mechanical co-efficient of heat, or to 

 expatiate further on the larger doctrine of the Conservation of Energy, in 

 which it plays an important part. Such subjects would serve admirably for 

 many of our members who, like myself, amuse their leisure with the literature 

 of science. There are, I have no doubt, very many amongst us far better 

 acquainted with the progress of modern science than I am, and I hope that 

 by their help we shall at least show «n U™* «„ t~> . • **_ _._,.._.._ .___ 



