Where the alterations are considerable, and particularly where insertions or omissions are to be made, there usually arises a necessity for over-running. In order to do this, they must decompose, or return the lines back from the galley into the composing-stick, to be rectified accordingly.
If one or more words to be inserted in a line cannot be “got in” by changing the spaces of the line for lesser ones, part of the line must be put back into the close of the preceding one, or forward into the beginning of the subsequent one, or both, till room is obtained. If the insertion be large, several lines will need to be over-run, either backward or forward, till a break is arrived at; when, if it will not come in, a line is to be driven out.
When an omission is to be made, the contrary course must be taken. If it be but little, the compositor takes it out, and drives out the remaining matter, either by enlarging her spaces, or bestowing the beginning of the following, or the close of the preceding line therein. If it be considerable, she may be obliged to over-run several lines before it can be driven out.
As to the faults which escape the reader and compositor, they are usually noted in what is called the errata.
The type, then, being composed and corrected in the galley, she measures off enough for a page, ties it up with a cord, and proceeds to the next, till all the pages required for the sheet are completed; this being done, she carries them to the imposing or correcting stone ([see p. 33]), there to range them in order in a chase. This is called imposing.
The chase is a rectangular iron frame of dimensions which vary according to the size of the paper to be printed on. It has two cross pieces of the same metal, called a long and short cross, mortised at each end into the frame so that they may be moved if necessary.
By the different situations of these crosses, the chase is fitted for different volumes; for quartos and octavos, one traverses the middle lengthwise, the other breadthwise, so as to intersect in the centre, which is the most customary situation; for twelves and twenty-fours, the short cross is shifted nearer to one end of the chase. For folios, the long cross is left entirely out, and the short one placed in the middle; and for broadsides, or sheets printed on one side only, both crosses are set aside.
To dress the chase, or range and fix the pages in it, a set of furniture is made use of, consisting of reglets or slips of wood of different dimensions, which are only about half an inch high, so as to be lower than the letters. Some of these are placed at the top of the pages, and are called heads; others between them to form the inner margin, called gutters; others at the sides, called side-sticks; and others at the bottom, called foot-sticks.
The pages then being placed in order on the stone, the chase is put over them, the furniture applied between the pages and the chase in the positions above mentioned; and the whole is locked up by means of small pieces of wood, cut in wedge form, called quoins, which are driven with a mallet and shooting-stick to a sufficient tightness. In this condition, the work is called a forme, containing more or less pages according to the size of the volume.
Before the forme is quite locked up, it is pressed down by passing a smooth piece of wood, called the planer, over the letters, to make their surfaces stand flat and even; and, when locked up, it is tested, to see that nothing is loose.