The Backus pin-setter is almost human in its operation. The old way was to hire boys to set up the pins on the spots and return the ball via the return chute. The pin-setter relieves the boy of the major and most time-consuming part of this work. A frame holding the machine is set up over the spots. It is placed so high that it does not interfere with either the flying pins or the rolling balls. As the pins are knocked off into the gutters, or the pit, the pin boy picks them up and lays them flat on their sides into the pockets at the top of the machine. When a “frame” is rolled those pins standing on the alley remain there and the machine is lowered by a balance weight controlled by a lever. As it descends the pins are automatically set on end, and when they rest on the spots on the alley the machine releases them and springs up to its original position. Wooden balls for bowling were never satisfactory. They wore out too easily and never retained perfect rotundity. Fortunes were spent in experimenting with other materials until at last the famous “mineralite” ball was perfected. Its composition is a trade secret, but its chief ingredient is rubber. First the composition is rolled into sheets. These are then molded and later vulcanized, being subject to terrific pressure. The balls are then smoothed and polished. As it is impossible to make a perfectly round ball and have the weight equally distributed, the ball can not roll true; an ingenious device overcomes the difficulty. The ball is set in a basin of mercury, where it floats. Naturally, the heavier side of the ball swings to the bottom. On the top, diametrically opposite to the center of weight, a chalk mark is placed on the ball and it is then lifted out of the mercury. Diametrically opposite to the chalk mark a small hole is punched into the ball to indicate the weightiest point. Directly beneath this is stamped the trademark of the firm. Having ascertained the proper distance apart the finger holes are to be bored, the ball is weighed to determine the excess of its proposed weight when finished. The holes are then machine bored at the respective points, sufficiently deep to reduce the weight to exact specifications. * * * * * How are Artificial Precious Stones Made? The art of manufacturing gems synthetically, that is, by the combination of chemical elements present in the real stone, has reached a high degree of success. The diamond, which is an allotropic form of carbon, has hitherto resisted attempts to reproduce it of sufficient size to have a commercial value. By dissolving carbon in molten iron and suddenly cooling the molten mass by a stream of water, whereupon the outer part contracts with great force and compresses the interior so that the carbon separates out, Moissan, the French chemist, succeeded in isolating small crystals, none, however, as large as one-twenty-fifth of an inch in diameter.