The publication of a modern daily newspaper with its many special editions would be well nigh impossible if we still had to depend upon hand setting of type. Tens of thousands of type characters are required to make up a single newspaper page, and although skilled hand compositors work with extreme rapidity it would take a large corps of men to set type for even a small newspaper in the short time available. Speed is of prime importance in newspaper work and the task of handling thousands of little pieces of type metal and arranging them correctly into words and sentences was long recognized as a serious handicap, but the problem of doing this work by machine was by no means simple one and baffled inventors for years. One of the principal difficulties lay in the size and shape of the type and another was that of justifying the lines, that is, providing just the right width of spaces between words to fill out the lines completely so that they would all be of equal length, giving a straight instead of a ragged margin to the column. After that came the problem of redistributing the type.
The first really successful composing machine was the invention of Ottmar Mergenthaler in 1888. Mergenthaler overcame the difficulties that had balked other inventors by attacking the problem from a radically new angle. Instead of setting precast type, his machine cast its own type from a set of matrices. By operating a keyboard, the matrices were assembled in a line which was justified automatically after the line was composed and then the whole line of type was cast in a single slug. Hence his machine earned the name “linotype.” Then the matrices were returned automatically distributed to the proper channels of the matrix magazine ready to be used over again for succeeding slugs.
[Illustration: FIG. 72--A LINOTYPE MATRIX]
A picture of a linotype matrix is shown in Figure 72. It is a plate of brass formed with ears _A_ at the four corners. The type mold is shown at _B_ and of course the thickness of the matrix varies with the width of the type letter it is designed to cast. In the top of the matrix there is a V-shaped slot _C_ formed with teeth which are designed to engage grooves in a V-shaped bar over the matrix magazine. The teeth on the matrices are variously cut away and serve as keys to the different channels of the magazine. There is a different combination of teeth for each letter of the alphabet and all matrices of the same letter have the same combination of teeth. The teeth on the distributing bar are also cut away according to various combinations. After the line has been cast the matrices are all raised by their ears and fed one by one upon the distributing bar. Each matrix moves along until it arrives over the channel it is designed to enter when it comes to a gap in the teeth of the bar that are supporting it and drops into the magazine. Although there are but seven teeth on each side of the V-shaped bar, there are more than enough combinations possible to provide a characteristic one for every key of the keyboard. A matrix always has at least one pair of teeth in engagement with the bar until it reaches the gap that lets it fall into its own special channel of the magazine. The number of matrices of each character varies with the normal frequency of use of that letter. For instance, the letter _e_ is very commonly used, and there must be many more _e_ matrices than _z_ matrices, but in any case the number need not be very large because the process of casting a line and redistributing the type does not take very long and the matrices are soon back in the magazine ready to be used over again. The casting and distributing operations are entirely automatic and while they are in process the compositor is setting a new line.