Page:Popular Science Monthly Volume 43.djvu/742

722 industries, in a general building, it has a temple of its own, which is filled with the manifold applications of this strange and subtile agent to the arts and conveniences of life. And even this is inadequate to the demands it has made upon the space of the exposition, for what may rightly be considered two of the main exhibits—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 summing 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 exposition, 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 Columbian 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 instruments, 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 elsewhere, 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 inspection much better than by mere description this most important 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