MODERN VIEWS WITH RESPECT TO ELECTRIC CURRENTS 667 



force in the luminiferous ether drawing the bar upward by their con- 

 tractile force. This contractile force is no small quantity, as it may 

 amount, in some cases, to one or even two hundred pounds to the square 

 inch, and thus rivals the greatest pressure which we use in our steam 

 engines. 



Thus the luminiferous ether is, to-day, a much more important factor 

 in science than the air we breathe. We are constantly surrounded by 

 the two, and the presence of the air is manifest to us all; we feel it, he 

 hear by its aid, and we even see it, under favorable circumstances, and 

 the velocity of its motion as well as the amount of moisture it carries is a 

 constant topic of conversation with mankind at large. The luminifer- 

 ous ether, on the other hand, eludes all our senses and it is only with 

 imagination, the eye of the mind, that its presence can be perceived. 

 By its aid in conveying the vibrations we call light, we are enabled to see 

 the world around us, and by its other motions which cause magnetism, 

 the mariner steers his ship through the darkest night when the heavenly 

 bodies are hid from view. "When we speak in a telephone, the vibra- 

 tions of the voice are carried forward to the distant point by waves in 

 the luminiferous ether, there again to be resolved into the sound waves 

 of the air. When we use the electric light to illuminate our streets, it 

 is the luminiferous ether which conveys the energy along the wires as 

 well as transmits it to our eye after it has assumed the form of light. 

 We step upon an electric street car and feel it driven forward with the 

 power of many horses, and again it is the luminiferous ether, whose im- 

 mense force we have brought under our control and made to serve our 

 purpose. No longer a feeble, uncertain sort of medium, but a mighty 

 power, extending throughout all space and binding the whole universe 

 together, so that it becomes a living unit in which no one portion can be 

 changed without ultimately involving every other portion. 



To this, ladies and gentlemen, we have been led by the study of elec- 

 trical phenomena, and the ideas which I have set forth constitute the 

 most modern views held by physicists with respect to electric currents. 



