The enumeration already given by no means exhausts the uses of the wonderful product evolved and perfected by centuries of study and toil. Widespread as is its use in the various departments of chemistry, and in all the graphic arts, it fills an equally wide field of usefulness in the mechanic arts, where it has become a staple. ♦Paper car-wheels♦ One of its most curious uses in this field is in the manufacture of car-wheels. The material is calendered rye-straw board, or thick paper, and the credit of the invention belongs to Richard N. Allen, a locomotive engineer. The paper is sent to the car-wheel shops in circular sheets measuring from twenty-two to forty inches in diameter, and over each of these is spread an even coating of flour paste. The sheets are then placed one above the other until a dozen are pasted together, when all are subjected to a hydraulic pressure of five hundred tons or more. After two hours’ pressure, these twelve-sheet blocks of paper are kept for a whole week in a drying-room heated to a temperature of 120° Fahrenheit, after which a number are pasted together, pressed, and dried for a second week; a third combining of layers is then made, followed by a month’s drying, until there is obtained a solid block, containing from one hundred and twenty to one hundred and sixty thicknesses or sheets of the original paper. The thickness is only from four and one-half to five and one-half inches, and in weight, density, and solidity the block resembles more the finest grained, heaviest metal than it does the original paper product. It may be called car-wheel paper. To complete the wheel, there are required a steel tire, a cast-iron hub, wrought-iron plates to protect the paper on either side, and two circles of bolts, one set passing through the flange of the tire, the other through the flange of the hub, and both sets through the paper. The paper blocks are turned on a lathe, which also reams out the center-hole for the hub; two coats of paint are applied to keep out moisture; the cast-iron hub is pressed through by hydraulic pressure; the other parts are forced into place, and the paper center is forced into the steel tire by like hydraulic power; and there, a product of human ingenuity, is a paper car-wheel, which never is injured by vibrations, and is safer and longer-lived, though costing more, than any other car-wheel made. ♦Paper lumber♦