THE EVOLUTION OF ELECTRIC AND 

 MAGNETIC PHYSICS. 



BY ARTHUR E. KENXELLY. 



THE subject for your consideration this evening is one of 

 the most interesting and important of all the topics which 

 have attracted the attention of the modern scientific thinker. 



In the earliest recorded observations of electric force it 

 appears to have been regarded as a phase or mode of vital- 

 ity. Thales of Miletus, the Greek mathematician whose 

 home was on the woody Asiatic shore of the -^Egean Sea, 

 twenty-five hundred years ago, noticing that amber after 

 being rubbed attracted or repelled light objects, such as 

 down or lint, is said to have attributed the property to some 

 condition of life resident in the substance. 



The centuries that have intervened have smiled upon so 

 superstitious a belief, but perhaps when futurity shall judge, 

 the thought, under a different interpretation, may not seem 

 so far astray; for to us of to-day vitality is stiirincompre- 

 hensible, and the very nature of electricity is enveloped in 

 mystery ; yet we know that whatever nerve force may be, 

 it "must at least be closely associated with electric force. 

 Nerve-fibers strangely resemble insulated wires ; electricity 

 can stimulate them into an involuntary performance of 

 their functions, while not a muscle contracts without elec- 

 trical manifestations, if care only be taken to observe them. 

 Even light, it would seem, falling on the retina, excites elec- 

 trical disturbances through the optic nerve, and it is possible, 

 if it is not at present demonstrated, that electricity may be 

 the active principle in the processes of animal vitality. The 

 relation between electricity and vitality may be so close as 

 to amount to identity. 



For twenty-two centuries after this first announcement, 

 electricity, one ever-present phase of the universal activity, 

 remained not absolutely unnoticed, but unknown. In the 

 saying of the Greeks, " There were brave men before Aga- 

 memnon," but not even the violence of thunder nor the 

 vivid lightning-flash can announce the facts of an all-envel- 

 oping environment to human intelligence of the highest 

 order we can boast until the progress of evolution shall 



