Hyperbolic Match Output

Number:26

Maker:ECKEL (The Eckel Co., USA)

Model:Engineer's Log Log (Circular Slide Rule)

PHOTO

Scales Front: || LL1, LL2, LL3, LL4, C || D, DI, A, K, L || Scales are printed on cursor

Scales Back: || SH1, SH2, TH, D, ST, S, T < 45°, T > 45° || Scales are printed on cursor

Gauge Marks:

Cursor Front:

Cursor Back:

Construction: Diameter about 8".

Date:

Source: Fahey

Information: This is the only known circular slide rule with hyperbolic scales that was manufactured and sold to the public. (See Appendix regarding, "The Everitt Complex Hyperbolic Slide Rule of 1924")
An article by Bill Robinson is also available at: https://osgalleries.org/journal/displayarticle.cgi?match=21.1/V21.1P45.pdf