To even mention the devices by which the manufacture of cotton and woollen fabrics, of shoes, of silks, and very many other articles, has been brought from rude processes to the rapid production seen to-day at our great industrial centres, would require a volume. To America is due the sewing-machine, which in the factory and in the household has given a manifold value to labor, has cheapened time, and is assuredly one of the chief triumphs of human ingenuity. We have done our part, too, in devising deadly weapons for contending armies. The revolver, invented by Samuel Colt, made a man armed with it six times as formidable as he was before; and the breech-loader, first attempted by John Hall of Yarmouth, Massachusetts, more than seventy years ago, was generally adopted in Europe. It is said that the greater number of the military arms made in the United States for Europe are on the breech-loading system. The invention of what is called the principle of "assembling," which consists in making the various parts of a machine "in distinct pieces of fixed shape and dimensions, so that the corresponding parts are interchangeable," has brought about a revolution in the manufacture of other articles besides fire-arms. It is applied also to watches, sewing-machines, knitting-machines, and even to agricultural implements and the building of locomotive engines. [Sidenote: Labor Saving Appliances.] The kitchen, the farm, and the sitting-room have been invaded by labor-saving appliances so numerous and so deft as to make each of these domestic departments a sort of factory in itself. The spinning-wheel has been abandoned for the sewing and the knitting machine, and the hand-plough for the steam-plough, and the scythe for the mowing-machine, and the rude kitchen knife and spoon for an endless variety of contrivances, from the apple-parer, the egg-beater, and the bean-shelters, to the lemon-squeezers, knife-sharpeners, and coffee-mills. [Sidenote: Various Inventions.] It is equally vain to attempt the enumeration of the improvements in the security of movable property, the rapidly changing devices for more effective fire-alarms, the revolution in the system of fire prevention with its steam-engine and its fire-alarm telegraph, the growing efficiency of the science of aerostation, the invention of scales for weighing heavy bodies, the processes for refining the precious metals, the achieved idea of making ice by machinery, the great advance effected in the making of glass, and the vast changes which have been wrought in many respects by the perfection of india-rubber as an article of common use. [Sidenote: Surgical Progress.] [Sidenote: Printing and Engraving.]