Figure 11 shows a model of a foundry crane, much admired for its accuracy of design and finish. It was made by George Chase, of seasoned maple with iron and brass connections. A swinging jib is pivoted at the top to a brass plate screwed to the cross-piece of the frame, and turns on a steel pin fitted to a plate on the base. A carriage travels along the jib, being kept at the required distance by a cord passing over a wheel at the end of the jib. A cord attached to the carriage passes over a pulley connected with the weight, and also over the wheel of the carriage, to the wheel directing it to the axle, which is turned by a cog-wheel and pinion taken from an old clock. The carrier of the elevator shown in Figure 12 is hoisted by a cord passing over a small iron pulley fixed to the cross-beam of the grooved posts, and thence to the spool, or axle turned by a crank. A clock-spring attached to a square wooden rosette is shown by Figure 13. Figure 14 represents a pump improvised by John B. Cartwright from an old mincing-machine. A handle turns a series of spur-wheels, which in turn give a rapid motion to a twelve-inch walking-beam. To one end of this walking-beam is attached a piston-rod, with a soft rubber disk working in a brass cylinder five inches long and three and a half inches in diameter. Iron fittings, including two brass valves, one on each side, connect with the cylinder; an air-chamber is formed with a fitting and cap. The suction caused by the upward motion of the piston will draw water from a pail or cup through a rubber tube connected with the end fitting of the right-hand valve, then through the valve to the cylinder; the downward motion of the piston causes the water to pass through the left-hand valve to the receiving vessel, and the air-chamber tends to make the flow regular. Parts of the machine were painted blue and striped with gold bronze. [Illustration: SIMPLE MECHANICAL APPARATUS MADE BY BOYS UNDER FOURTEEN YEARS OF AGE.--DRAWN BY J. ABDON DONNEGAN. Fig. 8 A DUMB WAITER Fig. 9. GUILLOTINE Fig. 10. A DERRICK Fig. 11. FOUNDRY CRANE Fig. 12. BRICK & MORTAR ELEVATOR Fig. 13. CLOCK SPRING Fig. 14. FORCE PUMP Fig. 15. SIMPLE SUN MAGIC LANTERN OR HELIOSTAT. Fig. 15.A. Fig. 16. ARC ELECTRIC LAMP] By the removal of one pane of glass from a window facing south, the apparatus shown in Figure 15 may be used, like a magic lantern, to project transparencies, in a darkened room. A pine board, fourteen inches square and one inch in thickness, has an opening in the middle to receive a wooden frame seven inches square, holding a six-inch cosmorama lens, having a focus of eighteen inches. A three-inch plano-convex lens having a focus of nine inches, mounted in a wooden frame, slides along a slit or opening in a board hinged to the inner side of the board which is cleated to the window.