Machinery is the active means by which the immediate transposition of the crude material into the finished article is accomplished. And in a building where the ceaseless belt moves with the rapidly revolving pulley may be seen the many forms of machinery which the active brain of the ingenious mechanic has devised to cheapen labor and increase production. The change of the cotton fiber into cloth, or the passage of the silken thread into the finished handkerchief; the revolving cylinder on which the virgin sheet of white paper becomes the printed purveyor of news; or the many and varied appliances by which the piece of leather is fashioned into a covering for the foot; or again the means by which the strip of steel is made into a pin or needle, are among the interesting things that may be seen in Machinery Hall. Conspicuous among the many interesting wonders of science that were shown at the Centennial, in 1876, were the few, insignificant, blue, flickering, and unstable lights that ushered into existence a new era in the history of electricity. In Atlanta, in Nashville, and in Omaha a building was necessary to hold the appliances and products of the latest of our sciences. Telephones no longer impress us by their newness, and the appliances of electricity to heating and lighting are now household necessities. To those who treasured the memory of the beauty of the lighted Court of Honor at the White City in Chicago there was given a greater joy when the entire grounds of the beautiful Centennial City in Nashville were illuminated with more than seventeen thousand incandescent lamps. Daylight had faded into darkness only to emerge into an electric day of brilliancy unsurpassed. Thus was told the story of the progress of the science which as a result of the studies of Franklin, Henry, Morse, and Graham Bell may well be regarded as the American science. A parting word must be given to the amusement features. How the Streets of Cairo, now so hackneyed, linger in one's memory! The Enchanted Swing was one of the novel features of the Midwinter Fair in San Francisco, and of weird interest was the Night and Morning in Nashville. The Mexican and Japanese villages were excellent features in Atlanta, and so was the Chinese village in Nashville, although the "Old Plantation" was more popular. Panoramas such as that of the Battle of Gettysburg, or pyrotechnic spectacular shows such as The Storming of Wei-Hai-Wei, are of value. The musical features must not be forgotten, even if popular fancy leans toward Dixie, for the occasional "Gems from the Operas" help to leaven the mass. At Nashville the military drills by the national and State troops were of considerable interest, and much had been hoped for in Omaha in this respect, but the war prevented.