In the same case is a plain model, roughly executed, representing the frame-work of the hull of a Western steamboat. Beneath the keel is a false bottom, provided with bellows and air-bags. The ticket upon it bears the memorandum, “Model of sinking and raising boats by bellows below. A. Lincoln, May 30, 1849.” By means of this arrangement, Mr. Lincoln hoped to solve the difficulty of passing boats over sand-bars in the Western rivers. The success of his scheme would have made him independently wealthy, but it failed, and, twelve years later, he became President of the United States. During the interval, the model lay forgotten in the Patent Office, but, after his inauguration, Mr. Lincoln got one of the _employés_ to find it for him. After his death, it was placed in the Washington case. The opposite case contains another memento of him—the hat worn by him on the night of his assassination. In a couple of cases, filled with machinery for making shoes, we see a number of handsome silk robes and Japanese articles, of various kinds, presented to Presidents Buchanan and Lincoln, by the Tycoon of Japan. The remainder of the hall is filled with models of machines for making leather harness and trunks, models of gas and kerosene oil apparatuses, liquor distilleries, machines for making confectionery, and for trying out lard and fat. Also, methods of curing fish and meat, and embalming the dead. A splendid model of a steel revolving tower, for harbor defence, stands near the door, and is one of the most conspicuous ornaments of the room. The other halls are devoted exclusively to models of patented machinery, and other inventions. The cases above and below are well filled; models of bridges span the spaces between the other cases, and those of the larger machines are laid on the floor of the hall. Models of improved arms, clocks, telegraphs, burglar and fire alarms, musical instruments, light-houses, street cars, lamps, stoves, ranges, furnaces, peat and fuel-machines, brick and tile-machines, sewing-machines, power-looms, paper-making machinery, knitting-machines, machines for making cloth, hats, spool cotton, for working up hemp, harbor cleaners, patent hooks-and-eyes, buttons, umbrella and cane-handles, fluting-machines, trusses, medical instruments of gutta percha, corsets, ambulances and other military establishments, arrangements for excluding the dust and smoke from railroad cars, railroad and steamboat machinery, agricultural and domestic machinery of all kinds, and hundreds of other inventions, line these three immense halls. Among the most remarkable is a machine to force a hen to lay eggs, and a silver worm hook, invented to fish worms out of the human stomach.