1594 JOHN NAPIER invented the logarithms to simplify multiplication
     and division arithmetic. (See also Chapter »Napier's Bones«!)
1620 EDMUND GUNTER used this concept and made logarithmic scales.
     Calculation was performed with the aid of a pair of dividers.
1622 WILLIAM OUGHTRED invented the »Slide Rule« as two linear or
     two circular sliding scales.
1650 EDMUND WINGATE and SETH PARTRIDGE improved the tool to our
     known shape with upper and lower stator and slider in between.
1850 AMEDEE MANNHEIM made a slide rule with a cursor and a useful
     combination of scales: X and X-square pairs on front side;
     sine and tangent scales on the back side of the slider - But
     the slider has to be turned to use these scales on front!
1902 MAX RIETZ modified and enhanced the »System Mannheim« with a
     X-cubic scale and mantissa scale on front and gaps with index
     lines on the back side: Now the slider could be read on the
     back side without turning the slider in the slide rule. 1925
     he added a reciprocal-X scale and scales for small angles.
1934 ALWIN WALTHER in the Technische Hochschule Darmstadt modified
     and enhanced the »System Rietz« for the needs of engineers: A
     Pythagorean scale on front was added. The mantissa scale was
     transfered to the rear long side and the sine and tangent
     scales to the front long side. The back side of the slider was
     now free for the exponential scales. This »System Darmstadt«
     became the base model for all the following improvements...
1936 PHILIP DALTON filed a patent for a FLIGHT COMPUTER: A circular
     slide rule to calculate "True Air Speed", "Altitude Correction",
     "Fuel Consumption", ... In cooperation with the US Army AirForces
     it became the famous  »E-6B«  to calculate also the "Wind Drift".
     "Dalton's Dead Reckoning Computer"  was used in WWII also by the
     US Navy, the British Royal Airforce, and (copied) by the Japanese
     and Germans.  The »E-6B« ( and its modifications ) are still in
     use today in pilot schools and by privat pilots.

     ... mainly based on the book of Dieter v.Jezierski »Slide Rules«


Clifford Stoll, Astronomer and "Computer Guru", famous for his NewYork-
Bestseller »Cuckoo'sEgg«  ( A good read: He discovered and helped the
authorities to break up a ring of hackers during the early days of the
internet - Other books are »Silicon SnakeOil« and »HighTech Heretic« )
founded ACME KLEIN-BOTTLE in 1998. For more details see his enjoyable


The »FESTUS MFG.CO.« was started in 1938 by Paul Jones in a lumber yard
in Festus, Missouri. Later the company was renamed »ACU-RULE MFG.CO.«
and moved to St. Louis. In 1945 the company produced wooden Trig slide
rules and the 1st manual was written by P.Jones himself. Later he hired
Prof.R.Middlemiss to write a new Trig-Mannheim manual. In 1946 Log-Log
slide rules were produced with metal core. In 1954 the company moved to
Mt.Olive, Illinois and VINYL (produced by BAKELITE) became the primary
material for slide rules.  For more details see the »FESTUS-HomePage«
by George E. Keane:

STERLING PLASTICS in Mountainside N.J. was founded in 1938 for the
manufacture of drafting instruments.  In 1961 plastic slide rules
were added and STERLING became well known for its very economical
models with its logo »(SP)«. To expand their successful low-cost slide
rule line, they bought ACU-RULE MFG.CO. in 1968. STERLING continued
using the »ACU-MATH« logo for their higher quality slide rules.

ARISTO, Hamburg-Altona / Germany

In 1862 the company was founded by J.C.Dennert and 1863, when M.Pape
became Partner, the company's name was changed to »DENNERT & PAPE«.
Theodolytes, drafting instruments and planimeters were produced. The
first slide rule was made 1872. In 1888 the company got a patent for
an »Unchangeable Ruler«, a celluloid veneer on mahogany. This set a
new standard for slide rule design. 1936 the new material »ASTRALON«
(PVC polymer) was used instead and the company's name was changed to
»ARISTO«. In WWII the production was signed with »gwr« . After WWII
»ARISTO« set new standards with their model lines »SCHOLAR« for
students and »STUDIO« for engineers.

ARISTO's Year Code  ( Pressed on Rear or Side )
1939 - 1959   3 or 4 figures for year and lot;
===========   »G« for production in Geretsried.

    eg.:      »G6013« = Geretsried, 1960, lot 13

1959 - 1978   3 or 4 numeric or alpha codes for factory and year
===========   and 1..3 figures for its lot.

    Factory:        Character or Figure = Factory
                        H          2      Hamburg
                        G          3      Geretsried
                        W          4      Woergl

    Year Coding:    A R I S T O F L E X
                    0 1 2 3 4 5 6 7 8 9

    eg.:      »HFL5« = Hamburg, 1967, lot 5

              As the material was changed from ASTRALON to TERLURAN,
              a T was added in front of the lot.

    eg.:      »2LST4« = Hamburg, 1973, (TERLURAN) lot 4

AWF, Berlin / Germany

The  "AWF"  stands for  "Ausschuss fuer wirtschaftliche Fertigung"
(~ "Commission for Effizient Production" ). It was founded in 1918
"... to encourage team-work and the creation of the basis for the
communication of the latest knowledge and experience relating to
production efficiency." The commission worked on a multitude of
practical problems and solutions. The "Committee for Calculating
Technology" ( = ART = Arbeitsgemeinschaft fuer Rechentechnik )
was responsible for slide rules.

   ( Based on a text from ... )

Charles Bruning (1866-1931) was an immigrand from Denmark.
In 1897 he set up a blueprinting company in Manhattan.
Around 1920 he purchased American Blue Print Company of
Chicago, and the firm became the "Charles Bruning Company".
The company's 1921 catalog lists 11 slide rules. By 1952
most slide rules sold by Bruning were all-metal slide rules
manufactured by Pickett & Eckel. In 1963 the Charles Bruning
Company merged with the Addressograph-Multigraph Corporation.

CONCISE CO, LTD., Tokyo / Japan

CONCISE CO., LTD. was established in 1949 as a manufacturer of
circular slide rules. Since than additionally they made drawing
and measuring tools, traveling goods and stationery as quality
products until today...

DIETZGEN, Chicago / USA 

The firm was found 1885 from the German immigrand EUGEN DIETZGEN. 
Besides slide rules they produced and imported drawing materials
and surveying instruments. After 1910 there was a cooperation with
German's Faber(-Castell) until the end of the slide rule era. 1943
a cooperation with K&E started with the »MANIPHASE« models.

DIWA, Gentofte / Denmark 

DIWA was founded 1924 for making measuring devices and became a
well-regarded maker of slide rules especially in the Scandinavian

ECOBRA, Nuernberg / Germany 

The firm was founded in 1893 under the name EICHMUELLER & CO. to
make drafting compasses. Eugen Dietzgen was major (American) customer.
His partner Joseph Dietzgen acquired the factory in 1909 after the
death of Eichmueller. In 1922 the name was changed to BAYERISCHE
REISSZEUGFABRIK. The company made slide rules just before WWII under
the brand name ECOBRA, derived from  Eichmueller & CO.-Bayerische
Reisszeugfabrik AG.  And here again Eugen Dietzgen was the main
customer. The slide rules were made of aluminum alloy and after 1950
in an improved version. The metal was sprayed with white enamel, the
scales were printed and finally a coat of lacquer was applied.

FABER-CASTELL, Stein bei Nuernberg / Germany

In 1861 Baron Lothar v.Faber founded the famous pencil factory in
Stein and a factory for drafting equipment in Geroldsgruen. In 1892
their first slide rule with the »Mannheim« scale on boxwood came
on the market. In 1935 F-C marketed first successfully A.Walther's
»System Darmstadt«. Before WWII, F-C was the first company to offer
a slide rule with an ADDIATOR on its back side. After 1952, with
new production techniques, inexpensive, but high quality slide rules
were made for students (eg. »Duplex D-Stab« 52/82 with a T2-scale!).
With F-C's famous model »NOVO-DUPLEX« an old idea was adopted: An
»extended« root scale was folded at the square root of 10. It let a
10" slide rule have the precision of a 20" - or a pocket-sized 5"
have the precision of a 10" slide rule.

GILSON SLIDE RULE CO., Stuart, Florida / USA
   ( Based on a text from  WWW.SLIDERULEMUSEUM.COM ... )

Clair A. Gilson founded the company in 1915, in Niles, Michigan.
His 1st circular slide rule was printed paper glued to a 4" diameter
steel disk.  He purchased the Richardson's Rule Works around 1919
presumably to obtain the printing process for scales used on the
Richardson Rules. The family relocated to a small island near Stuart,
Florida, after 1927. The founder's son, Richard A. Gilson, computed
the scales for the Gilson Atlas while still a teenager. The company
was sold in 1960 to Daniel W. Fagen. Clair died that same year.

GRAPHOPLEX, Paris / France

GRAPHOPLEX was a major slide rule maker in France, based in Paris.
Their SRs were made of plastic and have a very attractive design.

HEMMI, Tokyo / Japan

HEMMI was found in 1895 and became one of the top slide rule makers.
They where famous for using veneered bamboo: Resistant, light weight
and slides easily. In 1917 the trademark of HEMMI became the logo
»SUN« between "Sunrise" and "Sunset".

HEMMI's Year Code  ( Pressed on Rear or Side )
HEMMI introduced a year code, starts with  1950 = »A« ... 
and the month code starts with  January = »A« ...

    eg.:     »BF« = June 1951

50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75
A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z

 A     B      C      D     E     F     G    H      I     J     K     L

HOEHLER, Hohenneuendorf / (East-) Germany

The HOEHLER logo »HH« is printed on the table on its back side ...

   ( under construction )

... Later the same slide rules are produced by Praezisions Mechanik
Oranienburg with the logo »PMO«.

HUGHES-OWENS, ___ / Canada

   ( under construction )

IWA, Denkendorf / Esslingen / Germany

"IWA"  stands for  "Ingenieurbuero fuer wirtschaftliches Arbeiten"
(~ "Engineer's Office for Efficiency"). The company, founded 1926 by
Franz Riehle, became a leading source of special purpose slide rules
in Europe. IWA's predecessor in this field was the AWF company.

KEUFFEL & ESSER, Hoboken, New Jersey / USA

In 1867, as a mail-order house for art and drafting supplies, the
firm was founded by William J.D.Keuffel and Herman Esser. 1900 »K&E«
build a factory in Hoboken and started to produce its own celluloid
veneered mahogany slide rules. Dividing machines were imported from
D&P/Germany. In 1891 »K&E« got a patent for a »Duplex«, a two-sided
slide rule with a two-sided cursor.
It is common knowledge that »K&E« was the 1st company to make double-
sided slide rules. But, they were actually produced by Dennert & Pape,
ARISTO in Germany.

KLAWUN, Hannover / Germany

in Berlin-Charlottenburg; after WWII moved to Hannover ...

  ( see also under BUSINESS SRs ... )


  ... Under Construction ...

LAWRENCE, Peru, Indiana / USA

The  » Lawrence Slide Rule Company «  was founded in 1930 from
George L. Lawrence in Chicago. In 1938 the company  moved to Peru,
Indiana. In 1943 injection molded plastic cursors replaced the glass
magnifiers. The 1947 divorce gave the company to wife Vivian. She
married Frank C. Bozarth in 1948 and continued to make slide rules
until the end in 1967, as the factory burned down.

LOEBKER, Dresden / Germany

In 1932 P.Loebker founded the company  » LOEBKER & CO. «  in Dresden.  
After bankruptcy in 1947 the company was taken over from the employee
Horst Meissner and renamed  » MEISSNER KG « ...

LOGAREX, Ceske Budejovice / Czechoslovakia

The company was founded before WWII as a factory and shop for drawing
instruments. From 1948 to 1950 they belonged to L&C HARDTMUTH, which
made the »Koh-I-Noor« Pencils. After becoming a state run business,
LOGAREX made slide rules mainly for the Eastern Block.

   ( Based on a text from ... )

Around 1892 the Lutz Company began to manufacture drawing
instruments and artists materials in Guttenberg, N.J. After
WWII the firm imported SRs made in Japan by Ricoh/Relay.

MANTISSA, Dresden / (East-)Germany

The GDR run company VEB MANTISSA, founded 1972(..76) in Dresden, was
the fusion of two other slide rule companies:  MEISSNER KG, founded
1947 (after WWII; former LOEBKER, founded 1932) in Dresden and REISS,
founded 1882 in Bad Liebenwerder.  The logo  »M«  of »Meissner«
continued. All slide rules were made in good quality of plastic

MEISSNER, Dresden / (East-)Germany

   see MANTISSA ...

NESTLER, Lahr in Baden / Germany

In 1878 Albert Nestler (& T.Beck) founded a company to make drawing
and surveyor instruments and became a world competitor. Their first
slide rule was a »Mannheim«. In 1903 NESTLER marketed first success-
fully »System Rietz«. It was made of celluloid veneer on mahogany.
Their »PRAEZISION« model of 1912 had an »extended« root scale,
folded at the square root of 10. This gave a 10" slide rule the
precision of a 20". Later in 1962 their top-model »MULTIMATH-DUPLEX«,
also featured this idea.
(and FABER-CASTELL used it for their famous »NOVO-DUPLEX« too!)

NORMA, Kempten / Germany

In 1959 Sigurd Boehm founded NORMA-MECHANIK in Altusried im Algaeu
to make »Rechen-Scheiben« (= Circular Slide Rules ). In 1995 the
company moved to Kempten. For the currency conversion in Europe,
their (VISA sized) »EURO-Calculator« came 1999 on the market...

PICKETT & ECKEL, Santa Barbara, California / USA

In 1943 »PICKETT & ECKEL« was founded in Chicago, Illinois. In 1949,
after Eckel left, the name was changed to »PICKETT«. They moved to
Alhambra, and in 1964 to Santa Barbara, California. In the beginning
their duplex slide rules were made of gray magnesium alloy, but they
tended to become oxidized and powdery on the edges. Finally it was
replaced by the splendid working aluminum. Their models N3 and N4
with 32 scales belong to the most »loaded« slide rules ever made.
Around 1950 P&E promoted slide rules with a yellow body, because
its better contrast for the human eye. These yellow ones got »-ES«
extensions (for »Eye Saver«); traditional white ones got extensions
»-T«. P&E was the leading maker of light metal slide rules. Famous
became their »N600-ES« pocket slide rule, because it accompanied
the astronauts on board of five Apollo moon flights...
At the end of the era also yellow plastic slide rules were produced.

POST, Chicago / USA

In 1890 Frederick Post founded a firm to make drafting, engineering
and surveying supplies in Chicago. The »POST« brand name appeared
on all slide rules eventhough they were made by top German companies
(eg. ARISTO, FABER, NESTLER). From 1932 HEMMI / Japan manufactured
the »POST« slide rules until the end of the era in 1970.

REISS, Bad Liebenwerda / (East-)Germany

In 1882 the firm was founded by Robert Reiss as a mail-order house
for office and drawing supplies. Later REISS developed into a well-
known maker of precision instruments (eg. theodolites, planimeters,
drafting machines) and the largest manufacturer in the region. In
1912 their first »REISS« slide rule came on the market. Models with
»extended« root-scales (»STELLFIX«) were made in 1920. This gave
a 10" slide rule the precision of a 20". After WWII the company
became a GDR-run business and exported slide rules to the eastern
and western world. REISS was well known for their beautiful light
metal slide rules (eg. »PROGRESS«, Mod.3223). Plastic (»DECELITH«
= »ASTRALON«) was used later (eg. »DUPLEX«, Mod.3227 - With 30
scales it belongs to the most »loaded« slide rules).
( see also MANTISSA ... )


The SCIENTIFIC INSTRUMENTS Company of Berkeley, California / USA used
Japanese manufacturers ( Relay / Rocoh, Concise ) to produce »SIC«-SRs.

   see also Examples of SIC Slide Rules under CIRCULARs
       &  ELECTRO  Hyper/Vector-LogLog

SKALA / Poland

Start 1948, as a collective of small workshops, SKALA produced drafting
tools. 1956-1976 production of slide rules for the "Eastern Block".


   see ACU-MATH ...


Etienne Lenoir and his son Paul E.M. Lenoir were well known makers of
surveying instruments in Paris. Among other distinctions, they provided
instruments for Napoleon's army in Egypt, and Paul took part in that
campaign (1798). In 1814 Etienne Lenoir was named "Engineer to the King"
(Louis XVIII).  After his death ( he survived his son ) the firm's name
became GRAVET-LENOIR and later TAVERNIER-GRAVET.  In 1851 A.Mannheim's
prototype scale arrangement was first produced by TAVERNIER-GRAVET.

UNIS, Berville_Paris / France 

U N I S  means "Union Nationale Inter Syndicale", which was a protective
name invented in 1916 by a french chamber of commerce.  Goal was to unify
different french products under one logo with a standard of quality ...
May be to counter the famous "Made in Germany" ?  In this collection is
also an  ADDIATOR  made by UNIS under licence.

UTO, Vonge / Denmark
   ( Based on a text from  WWW.SLIDERULEMUSEUM.COM ... )

A maker of promotional slide rules used for advertising, UTO slide
rules are still made to this days.  "The UTO SR's made now are silk
screen printed on hard white PVC sheets, 7 - 9 bodies on a sheet, and
machined to final shape. The cursors are injection molded of acrylic.
The grooves for sliding the cursor are positioned to prevent the
cursor to touch the SR surface. The printing ink bonds chemically to
the PVC surface."  Courtesy of John Kvint, of UTO.

WICHMANN, Berlin / Germany

The WICHMANN company was founded in 1872 in Berlin and became a famous
mail-order house for drafting instruments. Like POST, the WICHMANN let
their instruments make from high quality special manufacturers. E.g. the
slide rule »1417« in this collection is made by NESTLER  and the »1870«
is made by AWF. 

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© C.HAMANN          05/29/17