_The Linotype._--The most revolutionary and perhaps the most important development in the printing art of this century has been the linotype machine. The laborious, painstaking, and expensive feature of printing has always been the setting and redistribution of the types, since each little piece had to be separately selected and placed in the composing stick, and the line afterwards “justified,” which means an apportionment of the space between the words so as to make each line of type about the same length in the column. The same separate handling of each piece was again involved in restoring the type to the case. Machines for thus setting and distributing the type had been devised, but the operation was so involved, and required so nearly the discretion of the thinking mind, that all automatic machinery proved too complicated and impracticable. In 1886, however, a machine was placed in the office of the _New York Tribune_ whose performances astonished and alarmed the old-time compositor. It rendered it unnecessary to handle the type, or even to have any separate type at all. It was the Mergenthaler Linotype machine, which automatically formed its own type by casting a whole line of it at a time. The first machine was invented in 1884, and patented in 1885, but it was subsequently reorganized and greatly improved in Pats. No. 425,140, April 8, 1890; Nos. 436,531 and 436,532, Sept. 16, 1890, and No. 438,354, Oct. 14, 1890. It is shown in the accompanying illustration (Fig. 130). By manipulating the keyboard, which resembles that of a typewriter, each lettered key is made to bring down from an inclined elevated magazine a little brass plate of the shape shown in Fig. 131, and which plate is called a matrix, because it bears on its edge at _x_ a mould of the type letter. There is a matrix plate for every letter and character used. These little matrices are spaced by wedges, as seen in Fig. 132, and are assembled, as in Fig. 133, along the side of a mould wheel having a slot in it which forms a channel between the aligned type-moulds or matrices on one side and the discharge mouth of a melting pot, in which molten type metal is maintained in a fluid state by a subjacent gas-burner. In the melting pot there is a cylinder and plunger, and when the plunger descends, it forces the molten metal up through the discharge spout into the slot of the mould wheel, and against the letter mould _x_ of each one of the composed or aligned matrices. The wheel is then turned with the matrices, and the metal in its slot is afterwards discharged in the form of a linotype slug, seen in Fig. 134, which is a metal plate bearing on its edge a completely moulded line of type ready for setting up in the form for printing. The jagged notches in the tops of the matrices (Fig. 131) are for co-operation with a distributer bar (not easily explained) for restoring the matrices to their appropriate magazines after being used.