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This scale rule was identified by Eliza Parke Custis Law, Martha Washington's granddaughter, as the "Box rule from the writing desk of my lamented grandmother." While Mrs. Washington may have used it for marking straight lines, laying out a grid on which to plot a needlework design, or measuring short lengths, the complexity of the scales indicate that it was likely originally part of a pocket set of drafting instruments manufactured for use by draftsmen, surveyors, and other gentleman-professionals. Mrs. Washington may have obtained this rule from one of the instrument sets owned by her husband.

See also W-220.


Rectangular boxwood scale rule with semicircular tab at one short end; the obverse of the rule is inscribed at the top with a scale of inches divided to tenths and a decimal foot scale, below which is a table of diagonal scales; the reverse of the rule is inscribed with a scale of equal parts (also known as decimal divisions of an inch) with six lines of inches divided into 15, 20, 25, 30, 35, and 40 equal parts; the top edge of the reverse is beveled.


c. 1750-1802





Overall: 4 3/4 in. x 1 3/8 in. (12.07 cm x 3.51 cm x 0.08 cm)

Credit Line

Gift of Mary Means Huber, 2004

Object Number


Colors (Beta)

Mount Vernon's object research is ongoing and information about this object is subject to change. For information on image use and reproductions, click here.
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