The difficulties of casting the linotype slug proved a serious handicap in the earlier days of the linotype. The product of the machine could not compare in quality with precast hand-set individual type, although it served very well for newspapers; but the machine is now so far perfected that it is widely used for magazine and book composition. However before this stage of perfection was reached the demand for a machine that could do a higher grade of work led to the invention of another machine known as the “monotype.” The monotype consists actually of two machines, one of which is operated by a compositor and the other operated entirely automatically by the product of the first machine. The compositor operates a keyboard and thereby cuts perforations in a long strip of paper. These perforations are arranged in characteristic groups one for each key. The perforated paper is then run through the second machine and in accordance with the various perforations the separate types are cast and assembled into justified lines. Air flowing through the perforations operates a pneumatic mechanism which brings the proper molds into position and casts the separate types. The method of justifying the lines is very interesting. As in the linotype the operator merely touches a space key at the end of each word, but at the end of the line the mechanism automatically estimates the spaces to be filled and divides this by the number of spaces so that a characteristic group of perforations is punched when the compositor shifts to the next line. In the casting machine the paper ribbon runs through backward and the space group of perforations is encountered before the line is cast. This automatically adjusts the mechanism to cast spaces of the requisite size to fill out the line exactly. WRITING BY MACHINE In one sense we have taken up the various machines employed in printing in reverse order. Of course the first machine used is the typewriter, after which comes the composing machine, and finally the press.