Electricity 



classical researches set forth in his "Heat as a 

 Mode of Motion," ascertaining the singular 

 power to absorb terrestrial heat which makes the 

 aqueous vapours of the atmosphere act as an 

 indispensable blanket to the earth. 



And how vastly has electricity, whether in the 

 workshop or laboratory, enlarged our conceptions 

 of the forces that thrill space, of the substances, 

 seemingly so simple, that surround us sub- 

 stances that propound questions of structure 

 and behaviour that silence the acutest investiga- 

 tor. "You ask me," said a great physicist, "if 

 I have a theory of the universe ? Why, I haven't 

 even a theory of magnetism! " 



The conventional phrase "conducting a cur- 

 rent" is now understood to be mere figure of 

 speech; it is thought that a wire does little else 

 than give direction to electric energy. Pulsa- 

 tions of high tension have been proved to be 

 mainly superficial in their journeys, so that they 

 are best conveyed (or convoyed) by conductors 

 of tubular form. And what is it that moves when 

 we speak of conduction ? It seems to be now 

 the molecule of atomic chemistry, and anon the 

 same ether that undulates with light or radiant 

 heat. Indeed, the conquest of electricity means 

 so much because it impresses the molecule and 

 the ether into service as its vehicles of communi- 

 cation. Instead of the old-time masses of metal, 

 or bands of leather, which moved stiffly through 

 ranges comparatively short, there is to-day em- 

 ployed a medium which may traverse 186,400 

 143 



