Albree Trulog Duplex Circular Logarithm Table

This is Norman Albree's pilot model for a two-sided circular logarithmic chart. The side labeled A has a double logarithmic scale arranged in a spiral of seven turns. Its outer edge is marked from 1 to 3.15. The inner edge is marked from .0 to .5. The side labeled B also has a spiral double logarithmic scale, marked from .315 to 1 on the outer edge and from .5 to 1 on the inner edge. A clear plastic cursor folds over the edge of the instrument and is pivoted at the center on both sides.
The A side is marked inside the fourth spiral: 19©45, and at the center: TRULOG DUPLEX. The B side is marked inside the fourth spiral: 19©45 (/) G. N. Albree, and at the center: G. NORMAN ALBREE. The instrument was received with a hand-sewn brown leather pouch. George Norman Albree, the inventor and donor, was an aeronautical engineer. See also MA*335484 and MA*335486.
Currently not on view
Object Name
slide rule
date made
after 1945
Albree, G. Norman
Physical Description
paper (part material)
plastic (cursor material)
wood (overall material)
metal (part material)
overall: 1.5 cm x 26.2 cm x 24.5 cm; 19/32 in x 10 5/16 in x 9 21/32 in
place made
United States: Massachusetts, Boston
ID Number
catalog number
accession number
Rule, Calculating
Chart, Logarithmic
Science & Mathematics
Slide Rules
See more items in
Medicine and Science: Mathematics
Slide Rules
Data Source
National Museum of American History, Kenneth E. Behring Center
Credit Line
Gift of G. Norman Albree
Additional Media

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