Quarters

Quartos, octavos, and twelves forms are imposed in quarters. They are called Quarters, not from their equal divisions, but because they are imposed and locked up apart. Thus half the short cross in a twelves form is called a Quarter, though it be indeed but one sixth part of the form. — M. When both the crosses are in a chase, it is divided into four parts; for some sizes, such as twelves and eighteens, they are unequal; yet still each division is called a Quarter, whether it contain more or less than the proportionate number of pages.