Hyperbolic Match Output
Model:Duplex Slide Rule No. 153 (For Electrical Engineer)
Scales Front: || L, K, A || B, CI, C || D, T, GΘ || Note: This is the first slide rule sold with Gudermannian hyperbolic scales.
Scales Back: || Θ, R Θ, P || Q, Q', C || LL3, LL2, LL1 ||
Gauge Marks: π, 2π, and marks c, p', p", and pΘ are on front scales C and D. On back scales on far right of P is SIN, and on far right of Q is COS; e is on LL2 and LL3.
Construction: 25cm.; Plastic face on laminated wood ; Cursor is framed. Adjustable metal brackets.
Date: 1933 - 1967
Source: Herman's Archive
Information: A variation of this rule exists with identical scales but no number; except the Q' scale is in red. Also, variations of the regular rule exist where the far right number on the Gq scale ends in either 4 or 6, all else on the rules seems the same.A variation exists with identical scales all black. A variation exists with no number, but with identical scales all black. A variation exists with no number, but with U.S. Patent number 1459857 on it. A VIRTUAL Hemmi 153 has been put on the Internet under code: http://tinyuri.com/kufjjx. A variation exists in 1938 with stator screws on the back of the slide rule .Was not shipped to U.S.A. during 1942-45. A VIRTUAL Hemmi 153 has been put on the Internet by Mark Armbrust.