Albree Trulog Duplex Circular Logarithm Table

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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
date made
after 1945
Albree, G. Norman
place made
United States: Massachusetts, Boston
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
ID Number
catalog number
accession number
Credit Line
Gift of G. Norman Albree
Rule, Calculating
Chart, Logarithmic
See more items in
Medicine and Science: Mathematics
Science & Mathematics
Slide Rules
Data Source
National Museum of American History