At the turn of the century, Robert Proctor first employed a measure
of twenty-lines of type to avoid the difficulty of the apparent size.
McKerrow preferred ten-line measurements but A. W. Pollard resisted this
change. Ten-line measurements make sense; they would save some time
counting lines and the division by ten would be easier. John Tarr, in his
1946/47 Library article "The Measurement of Type" (5th ser.
1: 248-249) offered a useful table of 49 to 220 millimeters with the
corresponding values in inches, pica points, and old bodies. Unfortunately,
his sixty-one calculations, either by
calculating machine, slide rule, or longhand, contain sixteen significant
rounding errors and one serious typographic mistake. No one has published
a correlated table since then.
In 1949, Bowers codified the work of the preceding bibliographers,
thereby encouraging successive generations to use the twenty-line
measurement. Nevertheless, one cannot easily convert from the
measurement of the printed image to the exact specification of point size.
Interested bibliographers have still needed to consult a variety of sources.
For the first time, this article draws together the work of many different
bibliographers, including the following.
