786 THE POPULAR SCIENCE MONTHLY. 



end of the plateau, we have no means of knowing definitely. Present 

 relative elevations can not be relied upon as safe evidence. It is prob- 

 able, however, that it was not far from the close of the rise, as other- 

 wise the bed of the canon, under the crest of the plateau, rising more 

 rapidly than at any other point, would be the highest poirt, and the 

 divide would be there instead of being several miles farther east. 



Altogether, this phenomenon affords a very interesting study for 

 the structural geologist and the geographer. 



RECENT WONDERS OF ELECTRICITY* 



By W. E. PEEECE, F. E. S. 

 II. 



LAST week, when we had the pleasure of meeting, I endeavored to 

 disabuse your minds of any such idea as that electricity was a 

 fluid, or, in fact, any kind of matter. I pointed out to you that every 

 electric phenomenon really was a form of that curious, mysterious 

 agency that exists throughout nature, that produces all the work done 

 on the face of the earth, that probably is at the root of life itself, called 

 energy. Nevertheless, we can speak of electricity as though it were a 

 distinct entity ; precisely in the same way that we speak of sound, of 

 light, and of heat. We know that sound and heat are not sensible to 

 the touch, or taste, or sight ; so electricity is of the same character, 

 and is invisible and insensible in every shape or form. Moreover, we 

 can not either create or produce energy ; there is only a certain fixed 

 quantity of energy in the universe, and all that we can do is simply to 

 transform it into its different shapes, such as I illustrated to you last 

 week. All physical phenomena, without a single exception, may be 

 traced to the mere transformation of this energy. I showed you on 

 the last occasion how, by simply winding a wire round a mass of iron, 

 and sending a current of electricity through the wire, we could produce 

 that form of energy called electro-magnetism. To-night I have to 

 speak of one or two other forms in which this energy does its work 

 forms in which, when electricity is transferred through matter, it does 

 work in some shape or another. The operation of the electric current, 

 when passed through chemical compounds in solution or liquid, is to 

 tear asunder the constituents of the compound, and to arrange them 

 on different sides. A simple means of illustrating this is a glass jar, 

 like the one before you, containing water and two glass tubes, each 

 fitted with a stop-cock. When an electric current is passed through 



* Lecture delivered before the Society of Arts, January 4, 1882, and reprinted from 

 the journal of the society. 



