The American Printer: A Manual of Typography / Containing practical directions for managing all departments of a printing office, as well as complete instructions for apprentices; with several useful tables, numerous schemes for imposing forms in every variety, hints to authors, etc.

by Thomas MacKellar

] or four middle spaces; three to an em, [

] or three thick spaces; and two to an em, [

] or two en quadrates, which may with propriety be reckoned among the number of spaces. Besides these, there is what is called the hair-space, which is cast extremely thin, and is found useful in justifying lines and assisting uniformity in spacing.

TWO-LINE LETTERS

Are equal in depth to two lines of the type in which they are to be used, and of proportionate width. They form the almost only proper type for principal lines in title-pages, and are used at the beginning of chapters and newspaper advertisements.

QUADRATES.

An em quadrate [■] is a short blank type, in thickness equal to the square of the letter of the fount to which it belongs; an en quadrate [▮] is half that size.