193, 194, 196, 197, is useful, not only as a straight-edge and try-square, but also for a number of graduations and tables which are stamped on it.

There are various forms, but the one in most common use consists of a blade or "body" 24"x2" and a "tongue," 16"x1-1/2", at right angles to each other.

Sargent's trade number for this form is 100.

It includes graduations in hundredths, thirty-seconds, sixteenths, twelfths, tenths, and eighths of an inch, also a brace-measure, an eight-square measure, and the Essex board-measure.

Another style, instead of an Essex board-measure, and the hundredths graduation has a rafter-table.