History of the Typewriter

— 40 — a second frame, K, which may be termed the line-wheel, moves horizontally from right to left. The movement of the latter makes the lines, and of the former, the pages of writing. The movement of the line-frame is given by two steel spur rods, Q, revolving in vertical bearings, the left one being impelled by a spring, R, which is wound up at the completion of each line by depressing the large ivory knob seen on the right side of the keyboard. The motion of the rods is communicated to the line-frame by a small brass rack, S. Both rods turn with line-frame during the progress of the writing. Their regular movement is controlled by an escapement wheel and pallets attached to the right spur-rod, the latter being connected by a link, F, with an arm projecting vertically from the oscillating bar, A, which operates the striking hammer. The same key stroke which moves the hammer produces an oscillation of the pallets, and allows the paper to move the distance of a letter and space. The oscillation of the pallets may be effected by a partial movement of the keys, so that the paper can be moved without moving the striking hammer, when it is required to make a space instead of a letter. “ By this means the inventor got rid of the space bar or key used in all previous and subsequent machines of this class, every key serving as a space key. The carbonized paper and writing paper are held in a clamp, resting loosely in an angular projection of the line-frame, whence they are easily and quickly removed for a fresh sheet of paper. It only remains to show how the paper is brought back to its starting point for a new line. To make the proper interval between the lines, the page-frame is provided with a rack, T, moved by a pawl of peculiar form and construction, it leaving the teeth always free, so that the frame may, at any stage of the writing, be moved in any direction. The pawl is operated by the depression of the large ivory knob seen on the right side of the keyboard, with which it is connected by a lever and vertical link rod. A page being completed, a new sheet of paper is placed in the clamp, and the page-frame is pushed back to the bottom of the grooves. The depression of the aforesaid knob restores the lost power of the line-frame and the type- wheel springs.” Pratt’s machine was by far the most complete and practicable machine which had appeared up to that date, and it is owing to its appearance, and the newspaper articles and discussions which it provoked, that we owe the type- writer of to-day.