Palmer's Computing Scale, issue one
Date: dated 1843
Inventory Number: 5464
Classification: Slide Rule
Dimensions:0.4 x 28.5 x 28.5 cm (3/16 x 11 1/4 x 11 1/4 in.)
Accessories: cardboard envelope with fabric tie (from Harvard University Libraries); two additional Palmer's scales, see 5465 and 5466
DescriptionYellowed cardboard square, with maroon, gold-embossed leather edges, joined at center by a metal fastener to a yellowed cardboard disc. A flowered pattern is engraved in each of the square's four corners. A second metal fastener is attached near the top of the top disc.
Printed on the cardboard square around the circumference of the top disc is a logarithmic scale carrying values 1 to 10. A diamond is printed to the right of the 1 mark; an "A" is printed near the 7.9 mark. Eight points on the scale are additionally labeled with a star and the following text: near the 4.6 mark, "Days / 8 perct"; near the 5.2 mark, "Days / 7 perct"; near the 6.1 mark, "Days / 6 perct"; near the 7.3 mark, "Days / 5 perct"; near the 1.5 mark, "Months / 8 perct"; near the 1.7 mark, "Months / 7 perct"; near the 2 mark, "Months / 6 perct"; and near the 2.4 mark, "Months / 5 perct".
Printed around the circumference of the top disc is a second logarithmic scale, also carrying values 1 to 10. Six points on the scale are additionally labeled with the following: near the 1.3 mark, "Cont"; near the 1.4 mark, "S. Feet"; near the 1.6 mark, "Acre"; near the 3.1 mark, "C"; near the 7.1 mark, a circle; and near the 8.9 mark, a square.
Directions for using the slide rule are printed on the back of the cardboard square, surrounded by an engraved geometric border.
This instrument, together with 5465 and 5466, is stored in a grey cardboard envelope with fabric tie from Harvard College Libraries. A Harvard College Library bookplate is affixed to the inside front cover the envelope; a pocket for circulation cards is attached to the back inside cover.
Signedface, center of top disc: PALMER'S / COMPUTING SCALE ;
face, top disc, bottom center: Entered according to Act of Congress in year 1843 by Aaron Palmer in the Clerks Office of the District Court of the State of Massachusetts ;
back, top right: HARVARD COLLEGE LIBRARY / GIFT OF / ESSEX INSTITUTE / SALEM / JAN. 17, 1922
on spine of cardboard envelope: Palmer's Computing Scale
Inscribedface, pencilled in top left corner: QA / P3 ;
face, pencilled in bottom right corner: QA / P3 ;
back, pencilled in top center: [crossed out] Math 9908.43 ;
on stickers on spine (bottom center) and face (top left) of storage envelope: OVERSIZE ;
on sticker on face of storage envelope, top left: QA / 111 / P3;
pencilled inside cover of storage envelope, top left: QA / 111 / P3
FunctionEarly circular slide rule used to solve mathematics problems, including multiplication, division, the calculation of interest, and geometry problems.
This first Issue of Palmer's Computing Scale was recalled within six to eight weeks, as several gauge points were missing ("D", "B.G.", and "W.G."; compare to 1993-1-0003).
Primary SourcesPalmer, Aaron. A key to the endless, self-computing scale, showing its application to the different rules of arithmetic &c. Rochester, NY: P.S. Stoddard, 1842.
ProvenanceOriginally owned by the Essex Institute in Salem, Massachusetts, this instrument was given to Harvard College on January 17, 1922. It resided in Widener Library, then the Cabot Science Library, before being transferred to the CHSI.
Related WorksFeazel, Bobby. "Palmer's Computing Scale." Journal of the Oughtred Society 3, no. 1 (March 1994): 9-17,
Feazel, Bobby. "Palmer's Computing Scale -- Revisited." Journal of the Oughtred Society 4, no. 1 (March 1995): 5-8.