How bright and happy the world looked from the open windows of the smoke-colored Art Palace. As they passed one of those windows, the White City some miles distant, gleamed afar over the blue lake like a radiant vision. Constantinople from the Golden Horn was not as celestial and beautiful. “White, Judge Bonney,” said old Ephraim. “Yes, my friend, it is built of Staff.” “Judge Bonney, what _is_ Staff?” “Staff is a mixture of plaster—often called plaster of Paris—and a small per cent of cement, into which are introduced frequent fibres of hemp, jute, or Sisal grass, to give it toughness, so that it may be bent, sawn, nailed, or bored, at will.” “How is it cast?” “It is cast in moulds. The plaster and cement are first wet up to the consistency of thick treacle, a layer of which is spread on the well-lubricated mould. Then follows a layer of the long, tough fibres; over this is poured another coating of the liquid plaster, covering in the fibre and filling the mould to the required depth.” “Are there many moulds?” “Yes, there are a thousand or more of different patterns and sizes, from those for casting plain staff-board for walls, to those for the most complex, beautiful, or fantastic ornamentation.” “Are statues ever made of it?” “Yes, both statues and statuary groups. The moulds are first fashioned in clay, then coated with staff.” “How long does it take to make it ready for use?” “Oh, in the course of half an hour the composition hardens sufficiently to be handled and taken away to the buildings in process of construction.” “How long will it last?” “If kept painted, it will withstand the weather for a number of years. If it cracks or crumbles off, it can readily be repaired with a brush or trowel, from a tub of the liquid mixture. It is fireproof, and, to a great degree, waterproof.” “They say, Judge Bonney, that there is a sidewalk there that goes all by itself. Is that so? Tell us all about it.” “The Multiple Speed Sidewalk is also called the Travelling Sidewalk, or the Locomotive Sidewalk. It is a mechanical device for facilitating travel on the long pier—nearly one half a mile long and two hundred and fifty feet wide—near the Peristyle, thus enabling the tourist to make the trip over the pier in ease and comfort, refreshed by the lake breeze. The sidewalk, which traverses the entire length of the pier on one side, returns on the other, making a loop at each end. It is on low wheels. There are two parallel sections, or platforms, one moving at a rate of three miles an hour, about ordinary walking speed, and the other at six miles an hour, an easy driving rate. One may ride on either section.” [Illustration: MICHIGAN AVENUE.] The Judge led the trio back to his room. It was crowded with people seeking information.