Lawrence Engineering Service
KEEP ISRM FREE!
1935 - Wabash, Indiana, 1938-1947 - Peru, Indiana
A 10 person shop owned by George Lee Lawrence and Vivian C. Lawrence

After a divorce became Engineering Instruments, Inc. 1947-1967 Peru, Indiana
Owned by Vivian C. (was Lawrence) Bozarth and Frank H. Bozarth

For an in-depth historical account, read David Rance's The Unique Lawrence (v3 May 2012) originally published in the Proceedings of the IM2011 hosted by the Oughtred Society.


George Lee Lawrence with third Wife Nellie Mowbray 1960



P001 Lawrence Pocket (5-B)

Lawrence Pocket (5-B) - 1964
Made in USA
Front Scale
A [ B, CI, C ] D, K
Back: Blank
Scans and Photos Contributed by Vern Estes.
This model was sold for $.40 each in the 1964 Estes Industries Model Rocketry Catalog. Vernon Estes founded the company on encouragement from G. Harry Stine, who founded the National Association of Rocketry (NAR) in 1958. Many rocketeers (including the ISRM Curator) were introduced as teenagers to slide rules through the Estes Technical Reports to calculate model rocket performance.


P173 Lawrence 6-0p Flashrule
GE & Westinghouse Lamps
Lawrence 6-0p Flashrule
GE & Westinghouse Lamps

Made in USA - (c)1946
Front Scale
ASA [ Shutter speed (5 scales), Feet ] F stop
Back: Instructions


REF Lawrence 6-Ow Flashrule Wabash Lamps
Lawrence 6-Ow Flashrule Wabash Lamps
Made in USA - Wabash, Ind. - 1935-1937
Front Scale
A [ B, C ] D
Back: Conversion Chart
Archive - Scan donated David Rance Collection Sassenheim, The Netherlands


REF Lawrence 8-A
Lawrence 8-A
Made in USA - Wabash, Ind. - 1935-1937
Front Scale
A [ B, C ] D
Back: Conversion Chart
Archive - Tom Dilatush Collection, California


Lawrence 8-B (1947)

ISRM 12.04.03.01
Lawrence 8-B
Made in USA - Wabash, Ind. - 1938-1947
Front Scale
A [ B, CI, C ] D, K
Back: Conversion Chart
Original Owner (written in well): Mary Elizabeth Exley, A-7, a relative of the donor.
Gifted to ISRM by Henry Eck, of Catonsville, Maryland.
1939 Instructions (12.5MB PDF) - Manual gifted to ISRM by Mark Hornung, Minneapolis, Minnesota, who found this in his parent's home


Lawrence 8-B (1947)

ISRM 12.04.03.01
Lawrence 8-B
Made in USA - Wabash, Ind. - 1938-1947
Front Scale
A [ B, CI, C ] D, K
Back: Conversion Chart
Belonged to Mike Konshak in 1961 when he was 14 years old
Mike, who happens to be the ISRM Curator, used this slide rule to calculate model rocket altiudes in Colorado with the National Association of Rocketry. His membership is NAR 896. and attended NARAM 2 and NARAM 3 held in Colorado Springs, Colorado. 50 years later, he was the Contest Director for NARAM 52, also held in Colorado.
Read Mike's article Slide Rules For Rocketeers (1.14MB PDF) written by Mike that was published in the Journal of the Oughtred Society. 2008 Vol 17.1.


S499 Lawrence 8-B Dumont
Lawrence 8-B Dumont
Made in USA by Lawrence for Dumont, Zanesville, Ohio
Front Scale
A [ B, CI, C ] D, K
Back: Conversion Chart


S499 Lawrence 8-B Dumont
Lawrence 8-B Dumont
Made in USA by Lawrence for Dumont, Zanesville, Ohio
Front Scale
A [ B, CI, C ] D, K
Back: Conversion Chart


S323 Lawrence 8-L Voltage Drop Motor Wiring
Lawrence 8-L Voltage Drop Motor Wiring
Made in USA - (c)1946
Front Scale
Distance to Load [ Load (Amperes), Voltage Drop % ] Cu Wire Size
Back: Motor and Wire Data


REF Lawrence 8-L Voltage Drop Motor Wiring
Lawrence 8-L Voltage Drop Motor Wiring
Made in USA - (c)1946 with Model Name Text
Front Scale
Distance to Load [ Load (Amperes), Voltage Drop % ] Cu Wire Size
Back: Motor and Wire Data
Archive - Scan donated David Rance Collection Sassenheim, The Netherlands


REF Lawrence 9-K Music Transposer
Lawrence 9-K Music Transposer
Made in USA - by Lawrence, Peru, Ind.- Copyright 1946
Front Scale:
Semitone Count, Chromatic Notation
[ Chords: Major, Minor, Augmented, Diminished ]
Chromatic Notation/Subscript, Piano Key
Back of Slide: Not shown
Back: Not shown
Well: Not shown
Archive - Scan donated David Rance Collection Sassenheim, The Netherlands


REF Lawrence Music Note Transposing
Lawrence Music Transposing
Made in USA - by Lawrence, Peru, Ind.- Copyright 1948 by Thomas
Front Scale:
Position for Harmony, Position for Transposing
[ Interval, Music Notes]
Music Notes (Diminished), Music Notes
Back of Slide: Not shown
Archive - Scan donated David Rance Collection Sassenheim, The Netherlands


S322 L.E. Waddington Musicians Rule
L.E. Waddington Musicians Rule
Made in USA - by Lawrence, Peru, Ind.- 1947
Front Scale:
Semitone Count, Chromatic Notation
[ Chords: Major, Minor, Augmented, Diminished ]
Chromatic Notation/Subscript, Piano Key
Back of Slide: Interval Ratios, Harmonic Series, Octaves
Back: Subscript Notation, Instrument tables
Well: Reference Frequency


ISRM Lawrence 10-B
Lawrence 10-B - c1942
Made in USA - Peru, Ind.
Front Scale
A [ B, CI, C ] D, K
Back: Conversion Chart
Note: Front side painted, Back screened on bare wood.
Donated by Henry (Hank) Beloit, Kingston, Ontario, Canada
See Hank's picture and bio with his personal slide rules in the Aristo 0970 Multilog and 870 (pocket) Multilog in the Aristo Gallery and the Faber-Castell 989 Complex Slide Rule in the Faber-Castell Gallery.


S386 Lawrence 10-B
Lawrence 10-B - c1942
Made in USA - Peru, Ind.- Note: 8-B graphics on back
Front Scale
A [ B, CI, C ] D, K
Back: Conversion Chart
Note: Both sides painted, then screened.


S029 Lawrence 10-B
Lawrence 10-B - Glass Magnifying Cursor c1940
Made in USA - Peru, Ind.
Front Scale
A [ B, CI, C ] D, K
Back: Conversion Chart
Note: This glass magnifying cursor is very rare and was later replaced by an injection molded plastic magnifier. The molding machines were not transferred to Engineering Services after the 1947 Divorce settlement.


ISRM Lawrence 10-B Magnifying Cursor
Lawrence 10-B - Plastic Magnifying Cursor c1942
Made in USA - Peru, Ind.
Front Scale
A [ B, CI, C ] D, K
Back: Conversion Chart (Black Ink on Wood)


Lawrence 10-B Magnifying Cursor

ISRM 11.03.23.01
Lawrence 10-B - Plastic Magnifying Cursor c1944
Made in USA - Peru, Ind.
Front Scale
A [ B, CI, C ] D, K
Back: Conversion Chart (Blue Ink on White Lacquer)
Note: Back is painted white before equivalents silkscreen was applied
Donated by David Sweetman


Lawrence 10-C Engraver's and Photographer's Proportional Calculator

ISRM 13.06.10.01
Lawrence 10-C Engraver's and Photographer's Proportional Calculator
Made in USA - Wabash, Ind. - circa 1946
Front Scale
Original Size) [ Copy Size, % Size ] % Area
Gifted by Judy Gorin of St. Louis, Missouri, daughter of Charles Meyerson
Charles B. Meyerson worked for Einson & Freeman Advertising Agency in Long Island City, NY from 1950-1953. He used the proportion calculator/slide rule for print ads/photos in newspapers, magazines and pamphlets they developed. Mr. Meyerson was a docent at the St. Louis Zoo for over 15 years and a member of the 1904 St. Louis World's Fair Society. He died in St. Louis in 2009.


REF Lawrence 10-C Engraver's and Photographer's Proportional Calculator
Lawrence 10-C Engraver's and Photographer's Proportional Calculator
Made in USA - Wabash, Ind. - circa 1946
Front Scale
Original Size) [ Copy Size, % Size ] % Area
Back Adv: Philips & Jacobs Chemicals
Archive - Scan provided by Barry Mcallister


REF Lawrence 10-D Lumber Calculator (1935)
Lawrence 10-D Lumber Calculator
Made in USA - Wabash, Indiana - 1935
Thickness [ Width, Length ] Board Feet
Back: Not Shown
Archive - Scan donated David Rance Collection Sassenheim, The Netherlands


REF Lawrence 10-D Lumber Calculator (1946)
Lawrence 10-D Lumber Calculator
Made in USA - Peru, Indiana - Copyright 1946
Thickness [ Width, Length ] Board Feet
Back: Not Shown
Archive - Scan donated David Rance Collection Sassenheim, The Netherlands


REF Lawrence 10-F Pricing And Inventory Rule
Lawrence 10-F Pricing And Inventory Rule
Made in USA - Wabash, Indiana - Copyright 1946
Discount, Mark Up [ Cost: Gross, Dozen, Each ] Selling Price, Inventory (Number in Stock)
Back: Not Shown
Archive - Scan donated David Rance Collection Sassenheim, The Netherlands


REF Lawrence 10-G Cutting Speed Calculator
Lawrence 10-G Cutting Speed Calculator Copyright 1946
Made in USA - Peru, Ind.
Front Scale
Cutting Speed (fpm) [ Diameter: Inch, Millimeters, Drill Size ] Spindle Speed (rpm)
Back Adv: Gargoyle Lubricants
Archive - not in collection.


REF Lawrence 10-G Cutting Speed Calculator
Lawrence 10-G Cutting Speed Calculator Copyright 1946
Made in USA - Peru, Ind.
Front Scale
Cutting Speed (fpm) [ Diameter: Inch, Millimeters, Drill Size ] Spindle Speed (rpm)
Back Adv: Donald Robertson & Company, Chicago, Illinois
Archive - Jim Cerney Collection.


REF Lawrence 10-N Printers Proportional Ruler
Lawrence 10-N Printers Proportional Ruler
Made in USA - Peru, Ind - Copyright 1946
Front Scale
Inches [ Inches, Picas ] Picas
Back: Not Shown
Archive - Scan donated David Rance Collection Sassenheim, The Netherlands


REF Lawrence 10-1 Model Builders Slide Rule
Lawrence 10-1 Model Builders Slide Rule
Made in USA - Peru, Ind - Copyright 1947
Prototype (Scale/Foot) [ Model: English, Rairoad Gauge, Metric , Prototype (Scale/Foot) ] Model: English, Metric ,
Back: Not Shown
Archive - Scan donated David Rance Collection Sassenheim, The Netherlands


REF Lawrence - Dupont 011
Lawrence - Dupont 011
Made in USA for Dupont Chemicals
Note: Same as Dietzgen 1767P National
Front Scale
A [ B, CI, C ] D, K
Back Scale
[ S, L, T ] Back: Conversion Chart
Archive - Scan donated by David Rance collection, Sassenheim, The Netherlands


REF Lawrence - Copyfitter 12-H
Lawrence - Copyfitter 12-H
Made in USA by Lawrence - Copyright 1946 by Owen T. Taylor, Dayton 7, Ohio
Front Scale
Measure Length of Picas [ Number of Lines, Length in Points, C.P.P. ] Characters, type size
Archive - Scan donated by David Rance collection. Sassenheim, The Netherlands


REF Lawrence - Copyfitter 12-H (Taylor Publishing)
Lawrence - Copyfitter 12-H
Made in USA for Taylor Publishing Co., Centerville, Ohio. Copyright 1946
Front Scale
Measure Length of Picas [ Number of Lines, Length in Points, C.P.P. ] Characters, type size
Archive - Scan donated by David Rance collection. Sassenheim, The Netherlands


REF Lawrence 12-J Pro-Rater
Lawrence 12-J Pro-Rater
Made in USA by Lawrence - Copyright 1946 by Owen T. Taylor, Dayton 7, Ohio
Front Scale
Dates (Months/Days)[ Days, Days. ] Premium
Back: Table of day factors for a year
Archive - Scan donated by David Rance collection. Sassenheim, The Netherlands


S030 Lawrence 250-BT
Lawrence 250-BT  
Made in USA - Peru, Ind. c1942
Front Scale
A [ B, CI, C ] D, K
Back Slider
[ S, L, T ] Back: Conversion Chart


REF Lawrence Code Maker Slide Rules Comparison
Lawrence Code Maker Slide Rules Comparison
Made in USA by Lawrence Engineering Services - Peru, Ind. c1939
Front Scale
Alphabet [ Alphabet, Alphabet Inverted, Numbers ] Numbers
Scans Donated by Kenneth Lewis Collection

Cover of Box ----- Open Box ----- Instruction Manual
Lawrence Secret Code Outfit came with two slide rules, for you and your friend, and set of instructions (copyright 1939) written by W. St John Maloney which includes Vigenere table. The box is 8 15/16" Long, 3" Wide, 1/2" Thick


REF Lawrence - Miller Motor Company
Air And Hydraulic - Boosters And Accumulators
Lawrence - Miller Motor Company
Air And Hydraulic - Boosters And Accumulators

Made in USA by Lawrence - A Model 10-B with two added scales
Front Scale
DIA, A [ B, CI, C ] D, K, GAL
Back: Not Shown
Archive - Scan donated by David Rance collection. Sassenheim, The Netherlands


REF Lawrence - Low Pressure Gas Line
Flow Capacity Slide Rule, B.F. Grizzle
Lawrence - Low Pressure Gas Line
Flow Capacity Slide Rule, B.F. Grizzle

Made in USA by Lawrence for B.F. Grizzle, Copyright 1941
Front Scale
Length of Line, Specific Gravity [ Pressure drop (Inches), Pressure drop (ounces), Cubic Feet/Hr (B, A,)] Nominal Pipe Diameter (A, B)
Back: Not Shown
Archive - Scan donated by David Rance collection. Sassenheim, The Netherlands


REF Lawrence - Water Line Capacity Slide Rule, B.F. Grizzle
Lawrence - Water Line Capacity Slide Rule, B.F. Grizzle
Made in USA by Lawrence for B.F. Grizzle, P.O. Box 126,Terre Haute, Indiana, Copyright 1944
Front Scale
B (Inlet Gaauge Pressure), A (Outlet Gauge Pressure)[ A1 (Outlet Gauge Pressure), C (Pressure Ext.), Q (Cu. Ft per Day), L (Length in Miles)] D (Inside Diameter -inches), Spec. Gravity, Pressure Base, E, F (Pressure Extension), H (% line Looped)
Back: Not Shown
Archive - Scan donated by David Rance collection. Sassenheim, The Netherlands


REF Lawrence - Water Line Capacity Slide Rule, B.F. Grizzle
Lawrence - Water Line Capacity Slide Rule, B.F. Grizzle
Made in USA by Lawrence for B.F. Grizzle, Copyright 1944
Front Scale
Inside Pipe Diameter [ Length of Line, Flow Rate CuFt/Hr, Gallons/24Hr] Coefficient of Roughness, Loss of Head, Pressure drop]
Back: Not Shown
Archive - Scan donated by David Rance collection. Sassenheim, The Netherlands


REF Lawrence - Concrete Quantity Calculator (Prototype)
Lawrence - Concrete Quantity Calculator (Prototype)
Made in USA by Lawrence - Paper Scales, possibly a prototype/low volume rule
Front Scale
Thickness (A) [ Width or Height (B), Length (C) ] Volume (D)(cubic feet/cubic yards)
Back: Not Shown
Archive - Scan donated by David Rance collection. Sassenheim, The Netherlands


REF Lawrence - Antenna Slide Rule (RSC - Confidential)
Lawrence - Antenna Slide Rule (RSC - Confidential)
Made in USA by Lawrence for Radiation Laboratory, M.I.T., Cambridge, Massachusettes
Front Scale
Full Widths, Side Lobes [ Angle, Gain, Wavelenth ] Diameter
Back: Not Shown
Note: RSC = The Radiation Safety Committee
Archive - Scan donated by David Rance collection. Sassenheim, The Netherlands


REF Lawrence - Gamma-Ray Slide Rule
Lawrence - Gamma-Ray Slide Rule
Made in USA by Lawrence for ?
Front Scale
Exposure Time [ Thickness of Steel, Alloy Section, Film to Source Distance ]Milligrams of Radium, Equivalent Steel Thickness
Back: Not Shown
Archive - Scan donated by David Rance collection. Sassenheim, The Netherlands


REF Lawrence - Cutter Speed Calculator
Lawrence - Cutter Speed Calculator
Made in USA by Lawrence for Madison Manufacturing Co. Muskegon, Michigan Copyright 1947
Front Scale
Cutting Speed FPM [ Cutter Diameter, Madison Bar Diameter ] R.P.M.
Back: Not Shown
Archive - Scan donated by David Rance collection. Sassenheim, The Netherlands


REF Lawrence - "K" Factor Calculator
Lawrence - "K" Factor Calculator
Made in USA by Lawrence for Tokheim Corp. Fort Wayne, Indiana Copyright 1948
Front Scale
Degree Days [ Gallons ] "K" Factor
Back: Not Shown
Archive - Scan donated by David Rance collection. Sassenheim, The Netherlands


REF Lawrence - Liquid Propane Gas Calculator
Lawrence - Liquid Propane Gas Calculator
Made in USA by Lawrence for Tenbrook Enterprises. Kokomo, Indiana Copyright 1948
Front Scale
Gallons Corrected [ Gallons Delivered ] Propane Temperature
Back: Not Shown
Archive - Scan donated by David Rance collection. Sassenheim, The Netherlands


REF Lawrence - Traffic Managers Slide Rule
Lawrence - Traffic Managers Slide Rule
Made in USA by Lawrence - Copyright 1939 by M.T. Brockman
Front Scale
Class Rate [ Percent Class, Weight ] Rate and Charge
Back: Not Shown
Archive - Scan donated by David Rance collection. Sassenheim, The Netherlands


REF Lawrence - Poker Meter
Lawrence - Poker Meter
Made in USA by Lawrence - Copyright 1939 by M.T. Brockman
Front Scale
% Card Stud [ Recommended Plays ] 5 Card Draw
Back: Not Shown
Archive - Scan donated by David Rance collection. Sassenheim, The Netherlands

Lawrence Engineering Services OEM slide rules
Rebranded versisons. Also shown in other ISRM Galleries



REF Lawrence 8-B Anco Products
Lawrence 8-B_Anco Products
Made in USA by Lawrence for Anco Products Co.,
Painted wood body - Black text on top
Front Scale
A [ B, CI, C ] D, K
Back: Not Shown
Scan Donated by David Rance, The Netherlands


S495 Lawrence 505 U.S. Navy
Lawrence 505 U.S. Navy c1942
Made in USA - Peru, Ind. (Lawrence 10-B)
Painted wood body - Black text on top
Front Scale
A [ B, CI, C ] D, K
Back Slider
[ S, L, T ] Back: Conversion Chart


REF Lawrence 505 U.S. Navy
Lawrence 505 U.S. Navy c1942
Made in USA - Peru, Ind. (Lawrence 10-B)
Painted wood body - Red text on top
Front Scale
A [ B, CI, C ] D, K
Back Slider
[ S, L, T ] Back: Conversion Chart
Scan Donated by David Rance, The Netherlands


REF Charvoz-Roos SR-31
Charvoz-Roos SR-31 c1942
Made by Lawrence - c1942 (Same as 10-B) for Charvos Roos
Material: Painted Scales on Wood Stock
Front Scale:
A [ B, CI, C ] D, K
Back: Not Shown
Scan Donated by David Rance, The Netherlands


REF Lietz No.2974N
Lietz No.2974N c1942
Made by Lawrence - c1942 (Same as 10-B) for the A. Lietz Co. San Francisco, California.
Material: Painted Scales on Wood Stock
Front Scale:
A [ B, CI, C ] D, K
Back: Not Shown
Scan Donated by David Rance, The Netherlands


REF NOBEMA 10-B
NOBEMA 10-B c1942
Made by Lawrence - c1942 (Same as 10-B) for NOBEMA Products Co., USA
Material: Painted Scales on Wood Stock
Front Scale:
A [ B, CI, C ] D, K
Back: Not Shown
Scan Donated by David Rance, The Netherlands


S308 Dietzgen 1767P National - Early Cursor
Dietzgen 1767P National - Early Cursor
Made in USA by Lawrence Eng. Srv. c.1942 - See Lawrence 250-BT
Front Scale
A [ B, CI, C ] D, K
Back Scale
10in [ S, L, T ] 25cm, Conversion Chart (label)


S394 Dietzgen 1767P National
Dietzgen 1767P National - c1942
Made in USA - Same as Post 1446-D and Lawrence 250-BT
Front Scale
A [ B, CI, C ] D, K
Back Scale: [ S, L, T ]
Back: Early Conversion Chart (label)


S502 Post 1446-D Student circaWWII
Post 1446-D Student - cWWII
Missing Cursor, same as Lawrence 250-BT and Dietzgen 1767P
Made in USA by lawrence Engineering
Front Scale
A [ B, CI, C ] D, K
Back Scale
[ S, L, T ]
Back: Conversion Chart
Note: Because the transitional delivery of the 1446 during WWII from other OEM's tham Hemmi had the 'K' scale, once the war was over and shipping from Japan began again, the 'K' scale was added to the post-WWII Post 1446.


Engineering Instruments, Inc. 1947-1967 Peru, Indiana

1958 Sales brochure


REF Pocket Slide Rule with Lakeside Draft-A-Plan Kit
Pocket Slide Rule with Lakeside Draft-A-Plan Kit
Made in USA by Engineering Instruments, 1962
Front Scale
A [ B, CI, C ] D, K
Scan by ISRM
Slide rule owned by Richard (Rick) Krol, Decona, Colorado. Draft-A-Plan was a beginning drafting kit which had a small table, T-square, 30-60 and 45 degree triangles and this slide rule. Rick used this in 5th grade (11 years old) which inspired him toward a career in engineering. He works at Sun Microsystems.


ISRM Engineering Instruments Book Version
Engineering Instruments Book Version
Made in USA - Peru, Indiana
Front Scale
A [ B, CI, C ] D, K
Back: Conversion Chart
This model was included with the book Mathematics Made Simple


ISRM Engineering Instruments - No Model number (Lawrence 10-B)
Engineering Instruments - No Model number (Lawrence 10-B) - c1947
Made in USA - Peru, Ind.
Front Scale
A [ B, CI, C ] D, K
Back: Conversion Chart
Note: Front side painted, Back screened on bare wood.
Donated by Henry (Hank) Beloit, Kingston, Ontario, Canada
See Hank's picture and bio with his personal slide rules in the Aristo 0970 Multilog and 870 (pocket) Multilog in the Aristo Gallery and the Faber-Castell 989 Complex Slide Rule in the Faber-Castell Gallery.


ISRM Engineering Instruments 10-N, Printers Proportional Rule
Engineering Instruments 10-N, Printers Proportional Rule
Made in USA by Engineering Instruments, Peru, Ind. - 1947
Front Scale
Inches [ Inches, Pica ] Pica
(Note: Inches here are logarithmic, not linear)
Back: Blank, (a cursor was not required for this slide rule)
Owned by Alfred Wilcox who operated a two-person advertising agency in Breinigsville, PA until 1976. Donated by Ruth Moyer of Reston, VA, who's mother, Gladys Moyer, was employed by Alfred, as the other person in the shop.


P185 Engineering Instruments Codemaker
Engineering Instruments Codemaker
Made in USA by Engineering Instruments, Peru, Ind.
Front Scale
Alphabet [ Alphabet, Alphabet Inverted, Numbers ] Numbers
Back: Blank


REF C.V. Ore S-M Slide Rule
C.V. Ore S-M Slide Rule Ad, Popular Science, May, 1956 pg261, found by George Keane, Festus, Missouri.
C.V. Ore S-M Slide Rule - Copyright 1955
Made in USA by Eng. Inst.  for C.V. Ore, Harvey, Illinois
Front Scale (10 inch long stock)
DS [ CI, C ] D, DM
Back: Blank
Archive - David McFarland collection
See the Acu-Rule/Acu-Math gallery for a later plastic version.
Mr. C. V. Ore of Harvey, Illinois describes his slide rule, which sold for $1.50 in 1956, as follows: "The S-M Slide Rule is a simplified, multi-purpose calculating instrument designed especially for the beginner. It contains the basic scales of professional slide rules ( C, D, CI ) as used by engineers for 80 to 90 percent of their work. And in addition to the basic scales the S-M Slide Rule has two special purpose scales for teaching the beginner the mechanics of the slide rule and to aid him in reading conventional C, D, and CI scales."


P190 Dick Tracy Secret Code Maker
Dick Tracy Secret Code Maker
Made in USA by Engineering Instruments, Peru, Ind.
Front Scale
Alphabet [ Alphabet, Alphabet Inverted, Numbers ] Numbers
Back: Blank
Came with Magnifying Glass
Instructions 2.18MB PDF


S265 Gene Loewy 10-B
Gene Loewy 10-B (Circa 1954)
Made in USA by Eng. Inst.  for Gene Loewy, New York, NY
Front Scale
A [ B, CI, C ] D, K
Back: Conversion Chart


REF Engineering Instruments - American Log Log 77A
Engineering Instruments - American Log Log 77A
Type Duplex Log Log Decimal Trig - pre 1968
Made in USA by Acumath for Engineering Instruments, Peru, Indiana
Front Scale
LL01, K, A [ B, T, ST, S ] D, L, LL1
Back Scale
LL02, LL03, DF [ CF, CIF, CI, C ] D, LL3, LL2
Scan found by David Rance, The Netherlands


S031 Engineering Instr. 250-BT
Engineering Instruments 250-BT 
Made in USA - Peru, IN. 
Front Scale
A [ B, CI, C ] D, K
Back Slider
[ S, L, T ] Back: Conversion Chart


Engineering Instruments 250-BT

ISRM 14.01.10.17
Engineering Instruments 250-BT- New all plastic cursor
Made in USA by Engineering Instruments, Inc., Peru, Ind.
Front Scale
A [ B, CI, C ] D, K
Back Slider
[ S, L, T ] Back: Conversion Chart
Gift of the Bill Wehrend Collection, Palo Alto, California.


S195 Engineering Instruments 250-V
Engineering Instruments 250-V
Made in USA - Peru, Ind. 
K&E 4058 cursor and sleeve (was Eng. Inst. an OEM to K&E?)
Plastic laminate over wood body
Front Scale
A [ B, CI, C ] D, K
Back Slider
[ S, L, T ] Back: Conversion Chart


Engineering Instr. 250-V

ISRM 11.03.23.03
Engineering Instruments 250-V
Made in USA - Peru, Ind. - Plastic Cursor
Plastic laminate over wood body
Front Scale
A [ B, CI, C ] D, K
Back Slider
[ S, L, T ] Back: Conversion Chart
Donated by David Sweetman


S528 Miller Motor - Air and Hydraulic Calculator
Miller Motor - Air and Hydraulic Calculator - Copyright 1950
Made in USA by Eng. Inst. for Miller Motor Co. Melrose Park, IL
Front Scale
DIA, A [ B, CI, C ] D, GAL
Back: Conversion Chart


Brief history

1901 - George Lee lawrence born in Chicago, IL.
Pre 1935 - Lawrence Slide Rule Company - George Lee Lawrence makes Photographic Slide rules in Chicago.
1935 - Lawrence Engineering Services was set up in Wabash, Indiana
1938 - Moved to nearby Peru, Indiana (10 man shop run by Ed Snyder)
c1940 - A glass magnifier was developed
c1942 - OEM supplier to Post (model 1446D) during WWII, when Japanese importation was halted. c1943 - Injection molded plastic cursor replaces fragile glass magnifier
1947 - A divorce settlement gives company to wife Vivian, briefly called Lawrence Engineering Company
c1948 - Vivian marries Frank C. Bozarth, forms Engineering Instruments, Inc. in Peru, Indiana
c1960 - Engineering Services OEM's the 77A plastic American Log Log (Acu-math 1500)
1967 - Company building burns down, Engineering Instruments ceases to exist.
1976 - George Lee Lawrence dies

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