Hyperbolic Match Output
Model:Duplex Slide Rule No. 154 (For Advanced Electrical Engineer)
Scales Front: || DF, P' , P || Q, CF, CI, SΘ0 || A, D, K ||
Scales Back: || Sx, Tx, TΘ0, TΘ0 || Th, Sh, Sh, C || D, L, Χ ||
Gauge Marks: π and mark c are on back scales C and D. NOTE: Rule has two cursors. Early version has scale letters etched on cursor glasses.
Construction: 50cm.; Plastic face on laminated wood ; Cursor is framed. Adjustable metal brackets.
Date: 1929 - 1967
Source: Herman's Archive
Information: A variation exists with no Hemmi number, but with U.S. Patent number 1459857 on it. Another variation exists with no Hemmi number, but the number 1-5708 on it to the right of the Sx scale. In 1932, Tamaya and Co., Tokyo, a Company that sold Hemmi slide rules, had a Hemmi No. 154 that was sold as Tamaya model No. 4499. Was not shipped to U.S.A. during 1942-45