7 22 THE POPULAR SCIENCE MONTHLY. 



industries, in a general building, it has a temple of its own, which 

 is filled with the manifold applications of this strange and sub- 

 tile agent to the arts and conveniences of life. And even this is 

 inadequate to the demands it has made upon the space of the ex- 

 position, for what may rightly be considered two of the main ex- 

 hibits the great alternating lighting plant and the direct-current 

 plant of the intramural railway are without the inclosure of the 

 Electricity Building, the one in Machinery Hall and the other in a 

 structure by itself. 



Complete and varied as the Columbian electricity exhibit is, it 

 is not primarily an exhibition of novelties. It is rather a sum- 

 ming up of our progress to date a slice taken from the far larger 

 exhibit which everywhere surrounds us and is helping to do the 

 daily work of the world in shop and factory and mine, on our 

 streets and in our homes. Much of that to be seen is already 

 familiar, but it is not on that account devoid of either interest or 

 instruction. In the actual industrial world the processes and 

 appliances of an art are scattered and not easily accessible, and it 

 can only be studied piecemeal and with difficulty. A great expo- 

 sition, on the other hand, gives an opportunity for studying an 

 art in its entirety, and thus enables an observer to gain a clear 

 conception both of the attained progress and the direction of 

 future development. This opportunity is afforded by the Colum- 

 bian in a marked degree. Illustrative examples are to be found 

 in it of all the more notable steps of progress, and many of the 

 exhibits are remarkably full and complete. 



The visitor will find, for instance, an opportunity to study the 

 telephone from its earlier form up to the present standard instru- 

 ments, and to inspect and perhaps understand for the first time 

 the central station system, by means of which he is daily put into 

 communication with other subscribers. He will see in actual 

 working what he will have but little opportunity to see else- 

 where, and which, to judge by the crowds which throng about it, 

 appeals strongly to the curiosity and interest of the average 

 visitor the delicate siphon recorder of Sir William Thomson, by 

 which all the cable messages of the world are received. And he 

 may perhaps wonder that any one should be able to interpret into 

 intelligible signals the curious zigzag scrawl which the siphon 

 leaves upon the moving band of paper. He will also see a set of 

 quadruplex instruments and be able to understand by actual in- 

 spection much better than by mere description this most impor- 

 tant of telegraphic appliances. He will also be able to see in the 

 Western Union exhibit the original receiving instrument of Morse, 

 made of a triangle of wood hinged at its apex to an artist's canvas 

 frame, and carrying at the center of its lower side a pencil, with 

 which a zigzag tracing can be made upon a moving band of paper 





