History of the Typewriter

— 28 — after each impression, and the slide, F, is pushed in the desired distance after each line. The ink can be obtained from pads on the springs, MM. This is a pleasant little machine to construct, to amuse the children on a winter’s evening, but although not a practical thing in itself, it served to suggest a locking device for a much more ela- borate instrument which we shall find explained in full in the section dealing with wheel machines. But if Thomas’s invention seemed to anticipate the Crandall, what part did the instrument devised by Cooper, in 1856, Fig. 13 play in regard to the invention of the Hammond ? In Cooper’s machine, there was a typewheel, working on a vertical axis, with radial type, brought into position opposite a vertical sheet of paper, and then, when in this position the wheel was locked, and a hammer caused the paper to strike on to the type from behind. From the “ Cantor ” lectures, we gather that this instrument had a dial plate on the same axis as the typewheel, by the aid of which a letter was selected, and the same handle that was employed for this purpose was employed to lock the wheel and to cause the hammer to deliver its blow. But whilst these minor instruments were being developed, one of the greatest scientists of the day was directing his mind to a solution of the various problems which arose. Sir Charles Wheatstone had, many years before, in- vented and patented his dial telegraph. “ He seems,” says Mr. Jenkins in his lecture before the Society of Arts, “ to have soon recognised the convenience that a machine- written message for delivery would be, and there is evidence to show that prior to 1850, he had constructed a working typewriter, in which a small square metal plate or comb carrying the letter, was employed in conjunction with a hammer, by means of which a selected letter could be impressed on to a strip of paper. Although not pub- licly exhibited, he had one complete machine at the time of