7.11 Specialty Slide Rules

While the majority of slide rules consisted of logarithmic scales for performing general calculations, many were designed for specific computations for very specific tasks. Just as a modern computer program might be used to perform a repeated calculation rather than typing in a series of similar computations again and again on an electronic calculator, special slide rules were developed for repeated calculations such as those found in the fields of electricity and electronics, chemistry, surveying, and so forth. Below is a list of slide rules that may be considered specialty rules in that they have scales specifically designed for use in a particular application or for a particular profession. Approximately 13% of the slide rules in the collection are specialty rules.

Maker Model Year Type Size Note
noID Comparative Rule
1880 L 9.00 nice boxwood Comparative Rule for alcohol taxation, likely from a Sikes’ hydrometer set; one side does comparative values; other side does reducing calc
Dring & Fage Inland Revenue Rule 1883-1902 L 12.00 Marked with address 145 Strand, London; used for alcohol excise tax purposes; 24 inch total length
E.S.A. London Harrow Mark Reducer 1898-1925 L 11.00 Educational Supply Association, incorp. 1898; rule was designed in 1875 by W.D. Bushell for the Harrow School, England, to reduce and calculate examination scores; 2 decades on stock, 3 decades on slide, 36 inch total length
Kolesch 2713 Stadia 1905-1911 L 10.00 stadia rule, 360deg, D.R.Patent No. 173660, likely made by Nestler; advertised in 1907 How to use Slide Rules; suede leather case; owner Everett Gowty, Perry, OK
K&E 4133 1913-1922 L 8.00 Roylance Electrical Slide Rule, mahogany, early release; prod mark 255; used and in poor condition; missing original 3-hairline cursor
K&E 4100 1915-1922 L 10.00 Stadia rule, early model, for use in surveying; instructions on back; all-glass cursor; prod marks 268 on end
Faber-Castell 379 1923 L 5.00 Electro rule; nice condition; pearwood; Made in Bavaria and date marks 3 and 12 on back; V and Eff scales in well; W gauge on C
Nestler 33 Chemiker 1924-1933 L 10.00 Early Chemical Rule, Albert Nestler A.G. LAHRi/B D.R. Patent Germany; Pickworth Data Slip on back; wide 1-line cursor
P.A.S. Co.  Engraving Rule
1928 L 5.50 Engraving Proportion Scale; sold by Art Brown & Bro. Inc. NewYork; similar to Hyde Optical Slide Rule at ISRM
Hemmi 80/3
1935 L 10.00 Electro; tables on back and text on box in French
Novotni Weight Calculator
1935 L 4.00 Novotni, but not marked as such; 13 inch o/a length; By-Products Steel Corporation; Commercial Trust Building, Philadelphia, Pa.
Lawrence 10-C 1935-1938 L 5.00 Lawrence Engravers / Photographers Proportion Calculator; Wabash, IN
K&E N4100 1938 L 10.00 Stadia rule, for use in surveying; instructions on back; metal rimmed cursor
noID Engraving Rule
1940 L 12.00 18 inch proportions rule, perhaps used in printing, engraving; maker? American Blueprint? (similar construction to U.S. Military Rule); A/B scales range from 1 to 30, 12 inches from 1 to 10
Baetzmann Spring Calculator 1941 L 2.00 Spring Load Calculations slide rule; large format 1 in x 2.5 in x 0.75 in; two slides on front, one on back; owner (maker?) R. K. Baetzmann, 1941
Felsenthal AN 5837-1 1943 C 8.00 Altitude Correction Computer; B/W main spiral scale, with fluorescent markings; WWII
Felsenthal D-4 1944 C 12.00 Time Distance Computer Type D-4; WWII device; Property of U.S. Army Air Forces; fluorescent numbers on black background
K&E N4133 1944 L 8.00 Roylance Electrical Slide Rule, mahogany; 3-hairline cursor; scale set #3; original case and box
K&E 4139 1946 L 10.00 Cooke Radio Slide Rule; Case: Polyphase Duplex DeciTrig 4071-3S
Lawrence 10-D
1946 L 3.75 Lawrence Lumber Calculator; Peru, IN
Lawrence 10-N
1946 L 6.50 Lawrence Printer’s Proportion Rule; Peru, IN
American Blueprint Military 1948-1957 L 10.00 US Military slide rule, for field artillery problems
Felsenthal FAA-95 1950-1955 C 8.00 MB-1 Computer, Air Navigation, True Airspeed and Altitude; true altitude correction spiral on back
J.B. Carroll Associated Spring M110 1952 L 10.00 early version, made for Associated Spring; no cursor
Blundell Rules Limited Radiac No. 1 1952-1956 C 2.00 radiation exposure calculator; log log scales; reversible land/sea discs; instructions on back
Pickett N1040-ES 1954 L 10.00 Fisher Control Valve Sizing Rule; made for Fisher Governor Co, Marshalltown, Iowa
Kahl Scientific Culbertson Slide Rule 1955 C 24.00 Temperature, Depth, Salinity calcs; Designed by Margaret Culbertson for the U.S. Navy Electronics Lab; full instructions
Hemmi 257 1956 L 10.00 Chemical Engineering; owner Frank Banks of CA
Pickett N1010-ES Trig Demonstration
1958 L 40.00 Demonstration rule; originally used in Michigan high school; 1/2 in x 9 1/2 in x 48 in
Pickett 14 1958-1962 L 10.00 U.S. military rule; well-worn leather case
Pickett N-515-T 1958-62 L 10.00 Electronics model; leather case, strap – great condition; Cleveland Institute of Electronics
Pickett N-515-T 1958-62 L 10.00 Electronic; basically new-in-box; leather case, strap – great condition; Cleveland Institute of Electronics
Concise 380
1959-1966 C 2.00 Radio Computer, with instruction sheet; Concise Co., Ltd. 
Felsenthal Dial-A-Con 1968 C 9.00 Flight computer, Type E6B, with instruction manual (by A. Fuchs), and vinyl case
Aristo 0958 1970 L 10.00 Geodat 400g stadia rule; instructions (German), clip-on supports; 5-hairline cursor; box and 1364 insert
C-Thru PS-79
1970 C 16.00 Proportional Scale, from the estate of Johnny Craig, noted comic book artist