History of the Typewriter

— 153 — sufficiently strong to withstand any ordinary amount of wear and tear. The inking is effected by means of a ribbon one inch (or rather fifteen-sixteenths of an inch) wide, and this ribbon passes from the front spool right over the typewheel, down between the latter and the paper, which, however, it is prevented from smearing by means of a shield, and winds automatically on to the second wheel. There is not an automatic return, but the ribbon may be reversed readily by touching a small lever. Fig. 119 The typewheel consists of a hollow drum of steel, which is threaded on to a suitable shafting, and does not only revolve but also slides from right to left as may be required. This wheel weighs only one-fifth of an ounce, and of course since all letters move together, there is no risk of any letter ever getting out of true and correct alignment. The rotation of the wheel is performed by means of the shaft, which turns on a strong coned pivot at either end, and means are provided for taking up any wear in this direction, although as a matter of fact, it is claimed that wear in this respect, although in theory possible, never in fact takes place in practice. In the centre of the wheel is a slot or groove, and into this slot enters a guiding arm, which carries the wheel to the right or left as may be required. When a key is depressed, the wheel moves until it is stopped, by means of a check pin, which is set up by the movement of the lever, and it is locked against any side play by means of the corrugations at each end of the wheel. The characters appear on the wheel in nine straight lines, three lines being employed for each “ case ” (i.e., lower, upper, and figures) and the depression of the shift-keys automatically rotates the wheel one-third of a revolution either way. Hence in