Images(2)

Rule, Slide

Object number2018.27.4 a,b

Manufacturer Keuffel and Esser Company

Datec. 1968

MediumWood; Metal; Plastic; Leather

Credit LineGift of Jay Apt

DescriptionSlide rule with leather case.DimensionsHeight x Width x Depth (a): 2.5 × 12.75 × 0.375 in. (6.4 × 32.4 × 1 cm)
Height x Width x Depth (b): 13.375 × 3.125 × 1.125 in. (34 × 7.9 × 2.9 cm)
Inscriptions(b) Handwritten text in black ink inside flap "APT".
Marks(a)
Maker's marks at right end: on both sides "10 / DECI-LON" and on one side "K+E".

Black text on right end on one side "U.S. PAT'S 2,422,649 / 2,500,460 2,534,695".

Black text at left end on one side "© 1947, 1961 BY / KEUFFEL & ESSER CO."

(b)
Gold text on front of flap "K+E" and front of case "10 / DECI-LON".
Historical NotesSlide rule and case purchased in 1967 and used by Jay Apt at Harvard University. This 2-sided slide rule was used by Jay Apt for multiplication, division, logarithmic problems such as chemical reaction rates and radioactive decay and trigonometric problems. He later acquired HP-35, HP-45, and HP-67 electronic calculators but kept this K&E slide rule in his NASA office and later in his home office.Label TextSlide rule with case used at Harvard by Jay Apt, c. 1968.

Previous owner Dr. Jerome Apt III

Related institution Harvard University

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