With the Bruce System
Second, the measurement in inches will help bibliographers examining
more recent books, especially American ones. Calculations in inches have
been carried to four places to the right of the decimal point. Such precise
information will serve those dealing with books from the nineteenth century
which have been set in type measured by the so-called Bruce System of
Geometrical Progression, which is calculated to at least four decimal points
(De Vinne, pp. 147-149). Although a rather curious system today, it was
the rational approach of George Bruce's "based on the theory that bodies
of type should increase by arithmetical progression—that small pica
should be made as much larger than long primer as bourgeois was larger
than brevier" (Updike, p. 33). His system, however, was not widely
adopted outside of his own foundry.