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Hemmi Bamboo Slide Rule Company

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Slide Rule History as writtem by the modern-day Hemmi Company in Japan.

Hemmi Catalogue Raisonne: Description of every numbered-model slide rule made by Hemmi Slide Rule Company of Tokyo,

Hemmi Catalogue II Description of every Hemmi slide rule that did not have a model number.

Hemmi Bamboo Slide Rule Company Ltd. in Japan is the oldest and most well known Japanese manufacturing company making slide rules. Jirou Hemmi and Company was founded in 1895 and, in 1912, was granted by the Japanese Patent Office Patent No. 22129 for their laminated bamboo construction method for slide rules. As a young company wanting exposure to a larger market, They started by selling distribution licenses to three other companies: the Fredrick Post Company of Chicago, Illinois, the Hughes-Owen Company of Canada and Tamaya & Company of Tokyo, Japan. Tamaya, an already a well-established and well-known firm in Japan, began selling Hemmi Slide Rules in 1913. The Hughes-Owen Company of Canada (another old firm), began selling the Hemmi Slide Rules in Canada in 1914 and in 1931, the Fredrick Post Company, of Chicago, Illinois, began selling them in the United States. All of three of these companies were selling Hemmi-manufactured Slide Rules under their own and Hemmi's name. Sun Hemmi also supplied re-branded OEM slide rules to other North American companies like Lafayette, Lietz, and Geotec. Early examples may have had the "Made in Japan" or "Made in Occupied Japan" sanded off due to anti-Japanese sentiments after WWII. It is estimated that Hemmi produced about 15 million slide rules altogether.

Also Canadian brands of Sun Hemmi, Hughes-Owens . and Geotec .
and Phillippine branded Sun Hemmi's sold as ODELCO
.
For the USA branded versions go to

This gallery begins with the long 20" slide rules, then continues by model number, sorted by date of manufacture.


Sun Hemmi 70 Improved Rietz (50cm scales) c1944

19.09.23.02

Original owner's name, "EMERY LARSEN" scratched under right label
Sun Hemmi 70 Improved Rietz (50cm/20" scales) c1944
Made in Japan by Sun Memmi
Physical dimensions of upper stock: 570mm x 34mm
Front Scale (extended): 50cm // A [ B, CI, C] D || 20in
Back Scale: [ S, S&T, T]
Cursor (62mm wide): 3 hairlines
Back Labels: Equivalents (English). Note: two identical labels end-to-end
Note: The hemmi 70 was given to Keith Wiley by the widow across his street as she aged, gave up so many things, and moved in with her daughter. Thanks to Keith for preserving the specimen by gifting it to ISRM


Sun Hemmi 154 Electronic (20" scales) with 2 cursors

ISRM 21.02.27.01

Page 62 25.8MB PDF
1951 Hemmi Bamboo Duplex Slide Rule Instructions
Sun Hemmi 154 Electronic with 2 cursors
Made in Japan by Sun Memmi, for Expert Electrical Engineers
Front Scale: Sx, Tx, Tθ [Th, Sh, Sh, C] D, L, X
Back Scale: DF, P', P [ Q, CF, CI, Sθ°] A, D, K
Belonged to Emory Leon Chaffee (1885-1975) a scientist who worked at the Harvard University Cruft Laboratory. He wrote many papers published in the Institute of Radio Engineers from 1916-1942. Invented the Chaffee quenched spark gap radio transmitter. MIT, PhD from Harvard. Verbal Interview at Niels Bohr_Library, Oral Histories - 1964. Taught the first course on vacuum tubes.


Hemmi 154 Electronic (20" scales) with 4 cursors

REF
Hemmi 154 Electronic with 4 cursors
Made in Japan by Sun Memmi
Front Scale: Sx, Tx, Tθ [Th, Sh, Sh, C] D, L, X
Back Scale: DF, P', P [ Q, CF, CI, Sθ°] A, D, K
Archive - Herman van Herwijnen's SRC 50741


Hemmi 200 Basic (16" scales)

ISRM 14.07.02.09
Hemmi 200 Basic
Made in Japan by Sun Memmi
Front Scale: D6, D5, D4 [C6, C5, C4, C3, C2, C1] D3, D2, D1
Back Scale: DF6, DF5, DF4 [CF6, CF5, CF4, CF3, CF2, CF1] DF3, DF2, DF1
Note: The six C, D, DF and CF folded scales gives an effective scale length ( 6 x 16") of 96 inches.
Gift of Ed Millis Collection, Texas.


Hemmi 201 Basic (20" scales)

REF
Hemmi 201 Basic
Made in Japan
Front Scale: L2.4, L1..3, L2.4, L1.3 [ C4, C3, C2, C1 ] D1, D2, D3, D4
Back Scale: K4,K3,K2,K1 [CF4, CF3, CF2, CF1] DF1, DF2, DF3, DF4
Note: The four C, D and K scales gives an effective scale length of 80 inches.
Archive - Herman van Herwijnen's SRC 50441


REF Hemmi 201 Basic (20" scales)
Hemmi 201 Basic
Made in Japan
Front Scale: Front Scales: L2.4, L1..3, L2.4, L1.3 [ C4, C3, C2, C1 ] D1, D2, D3, D4
Back Scale: K4,K3,K2,K1 [CF4, CF3, CF2, CF1] DF1, DF2, DF3, DF4
Note: The four C, D and K scales gives an effective scale length of 80 inches.
Archive - Herman van Herwijnen's SRC 56731


REF Hemmi 279 Expert Mechanical Engineering (20" scales)
Hemmi 279 for Expert Mechanical Engineer
Made in Japan
Front Scale: L, K, A [ B, T Cot, S Cos, ST, C ] D, LL0, LL/0
Back Scale: LL/1, LL/2, LL/3, DF [ CF, CIF, CI, C ] D, LL3, LL2, LL1
Archive - Herman van Herwijnen's SRC 24751



Hemmi "Sun" Type 98 Maneuvering Slide Rule c1938

ISRM 14.09.25.01


Japanese Battleship YAMATO


Hemmi "Sun" Type 98 Maneuvering Slide Rule
Made in Japan by "SUN"
Background: "Type 98" denotes that it was created in AD1938 (Koki or Jimmu Era 2598), which is 1938 in western calendars. The type 98 Movement rule, is a polar coordinate measuring system and was designed to calculate tracking and range data between two moving ships (or objects) to, possibly, provide input to the Type 98 Hoiban and Shagekiban Low Angle Fire Control computer which was specially designed for the Yamato class of battleships (the Yamato and Murushi). It could also have been used as the primary calculator for the smaller guns that were not connected the the electromechanical computers on the main battery of guns. This slide rule could also have been used for Ship-to-Shore or Shore-to-Ship bombardement as well. Another feature of this slide rule is that the Maneuvering Board, with its rotating dial on the slide, can be used to determine course corrections and wind drift. Handy if the battleship Yamato or an aircraft carrier, is to launch an aircraft, it will calculate the best heading into the wind. Submarines, would also use a similar device to calculate intercept vectors. The design of this slide rule mimics the maneuvering board/tables of the Allies, designed in 1920, and is still in use today. The center of the dial is 'My' or 'Own' ship.
Scales and markings translated by Jiro Higuchi
Front Scale: Relative Coarse Angle // Speed of My Ship [ Speed of Standard Ship, Distance (Logarithmic Scale) nautical mile/Meters, ] Velocity \\ Velocity Ratio
Back Slide: Time Board, Distance by reading Hour/Nautical Mile or Minutes/Meters
Well: Velocity Ratio =>1, Angle of course alteration, Velocity Ratio =<1
Case: Naugahyde with military division "Air Armament 9/90"
Gift of Phillip Rodley, Upper Hutt, New Zealand
On Left: Another of these slide rules was discovered in a bunker, located under a mountain behind the old Taura pyrotechnic factory, which manufactered torpedos during WWII, and stored them within. The buildings are currently part of the Maritime Self-Defense Force Yokosuka Zosamu depot and Akebono Machinery Co., Ltd. The bunker with its network of tunnels is not open to the public. See Yakumo's blog (in Japanese). Google will do a decent translation.


Sun Hemmi Model 1 (British Export Version)

ISRM 13.04.26.05
Sun (Hemmi) Model 1 (British Export version)
Made in Japan - pre1919, cursor.
Slide stamped: C.Baker, 244 High Holborn, London
Front Scale: 10 in // A [ B, C ] D || 28cm
Back Scale: [ S, L, T ]
Well: blank
Back: Equivalents in English


Sun Hemmi Model 1 (French Export Version)

ISRM 13.04.26.05
Sun (Hemmi) Model 1 (French Export version)
Made in Japan - c1928, cursor
Front Scale: 10 in // A [ B, C ] D || 28cm
Back Scale: [ S, L, T ]
Well: blank
Back: Equivalents in French
Gift of Phillip Rodley, Upper Hutt, New Zealand


J.Hemmi "Sun" Model 1 (Export Version)

REF
J.Hemmi "Sun" Model 1 (Export version)
Made in Japan - Pre 1927, has a post 1970 cursor
Front Scale: 10 in // A [ B, C ] D || 28cm
Back Scale: [ S, L, T ]
Well: 30-55cm
Archive - Scan donated by Olivier (France)


Sun Hemmi Model 1 (Export Version)

REF
Sun Hemmi Model 1 (Export version)
Made in Japan - c1930
Front Scale: 10 in // A [ B, C ] D || 28cm
Back Scale: [ S, L, T ]
Well: 30-55cm
Archive - Scan donated by Olivier (France)


Sun Hemmi Model 1 (UK Export Version)

ISRM 23.07.14.02
Sun (Hemmi) Model 1 (UK Export version)
Made in Japan - c1928, Type A "C" cursor
Front Scale: 10 in // A [ B, C ] D || 28cm
Back Scale: [ S, L, T ]
Well: blank
Back: Equivalents in English
Gift of Paul Ross, Missouri


J.Hemmi "Sun" Model 3 Electro c1919-1929

ISRM 12.03.15.02
J.Hemmi "Sun" Model 3 Electro c1919-1929
Made in Japan - Pre 1927, Japanese Patent No. 22129 (copy of AW Faber 387)
Patents: No221129 Note: Railroad track style divisions. Thin aluminum framed cursor.
Front Scale: 27cm // LL2, A(KW) [ B(HP), C ] D, LL03 || 10 in
Back Scale: [ S, L, T ]
Well: Dynamo(Motor), Volt


J.Hemmi "Sun" Model 3 Electro c1919-1929

REF



J.Hemmi "Sun" Model 3 Electro c1919-1929
Made in Japan - Pre 1927, Japanese Patent No. 22129 (copy of AW Faber 387)
Patents: No22129, No29714
Note: Railroad track style divisions. "C" cursor.
Front Scale: 27cm // LL2, A(KW) [ B(HP), C ] D, LL03 || 10 in
Back Scale: [ S, L, T ]
Well: Dynamo(Motor), Volt
Original owner C.W. Sewell. ( b? - c1978) Engine and gearbox/transmission designer for Bentley and Lagonda before and after WWII.
Archive - Photo provided by Scott Pattinson, grandson of owner.
Scott Pattinson writes; "CW Sewell was my maternal grandfather. He worked at Lagonda / Bentley motors. He was Bentley's chief designer, although W O Bentley claimed to hold that position, Bentley trained as a locomotive engineer and gave broad brush strokes to his team in reality. C.W. Sewell was also known as Rex Sewell. C.W. Sewell was part of the team that brought their cars to the Le Mans 24 hour race - one of the "Bentley Boys". During WW2 he worked for the government designing military vehicles, notably a jeep type amphibious vehicle that could be dropped by parachute and had some land mine resilience. He has also been referred to as the gearbox (transmission for US folks) wizard at Bentley. In a weird twist to my heritage, my paternal grandfather's company built the Brooklands race track on which Bentley cars and others competed. There was criticism of the track to be poor quality, however despite what you may read about that, it was built to the spec asked for and laying asphalt on banked surfaces was not a thing back then. CW Sewell died of prostate cancer when I was about 14 so about 1978. Tough for me, there are so many things I wished to have talked to him about." Proof of provenance: The Bentley vs Bentley case which states: "The 21/2-litre Lagonda was designed by C W Sewell, with S Ivernee, who were part of W O Bentley's team."


Japanese characters in Well


Fabric covered cardboard case

J.Hemmi "Sun" Model 6 150mm Pocket (1914-1929)
ISRM 13.12.21.01
J.Hemmi "Sun" Model 6 150mm Pocket (1914-1929)
Made in Japan by Sun Hemmi, cursor
Front Scale: 5 in // A [ B, C ] D || 15cm
Back Scale: [ S, L, T ]
Well: blank
Back: Equivalents in English
Note: Acquired out of the UK


Sun Hemmi "Byoutou" 苗頭 (Gunnery) 1944

ISRM 10.09.13.01

The following information is from Atsushi Tomozawa: The name "Byou-tou" comes from two Chinese characters "byou" 苗 and "tou" 頭 on a box containing a specimen of this rule in the Hemmi Offices in Tokyo. The first character translates to sprout, bud or shoot of a young plant; the second means "head." "Shooting Heading" is not an impossible translation. "Development History of the Slide Rule" by Jihei Miyazaki states that the Byoutou rule was introduced in 1944 but does not mention what function the rule served. Another book, "History of the Slide Rule," written for the Royal Navy Military Schools in 1944 explains how to use the rule to calculate a correction angle for firing at moving ships; the corrected angle is called "corrected byoutou" or deflection Gunnery

Notes from the curator, who used to work for Dr. Chen in 1985: "I asked Dr. Di Chen, a renowned Physicist in Lasers and Optics, to comment (on right) on this slide rule that he owned since he was in college. He stated he used it for electrical engineering classes, which conflicts with the speculations described on the left column. The back label instructions reference scales C, D and CI, but the scales on this rules are numbered sequentially 1 through 18. Dr. Chen did sctratch in scales labels on the slide over 60 years agao: (16)='D', (17)='K', (18)='A' and on the stock, (8)='B". The left index of A/B or (18)/(8) starts at 0.5 rather than 1. A very puzzling arrangement." Mike.

Sun Hemmi "Byoutou" 苗頭 (Gunnery) 1944
Made in Japan - 20 scales - used in electrical engineering classes in Taiwan.
Note: 250 x 34 x 11 mm. (Same body as Hemmi 50W.)
Front Scale: V, 10cm // 1, 12, 2, 11 [ 3, 12, 4, 15, 5, 14, 6, 13 ] 7, 8 || 9, 10
Back Slide (Reversible): [ 16, 17, 18 ]
Back: There is a plastic table on the back with settings for the C and D scales and trigonometry formulas; none of which seems to relate to this slide rule.
Cursor (Reversible): to align hairlines to the top and bottom edge scales.
Owned and donated by Dr. Di Chen, Mound, Minnisota

Dr. Di Chen bought this slide rule in 1950 while in his second year at the EE department of the National Taiwan University in Taipei, Taiwan. Dr. Di Chen has over 45 years of optical data storage experience. He received his Ph.D. in Electrical Engineering at Stanford University, and taught and did research at the University of Minnesota. He joined the Honeywell Research Center where he did pioneering research in magneto-optic recording and laser beam control. He and Nelson Yew founded Optotech Inc. in 1984, and introduced the world's first high density WORM drive and media to the market. He has published over 100 papers, presentations, and reports on optical data storage. Di is currently the President of Chen and Associates, a consulting company in the field of optical data storage.

Di Chen writes: "I bought this slide rule at a stationary store in Taiwan which was frequented by college students. So it is not likely that this slide rule is aimed for military purposes. On the other hand, there are some military schools in Taipei so I really cannot rule out that this product may be useful for them.

"The most common use of this slide rule is for mulitiplication and division, as well as some trigonometric functions. I don't recall using any other functions such as scale v. As I vaguely recall, reversing the sliding center bar expands the scale, and the bottom edge is probably related to angles for trigonometric funtions. "As the main scale for the basic functions are simply logarithmatic, other scales may be log log, for calculation of powers. I also recall that the cursor must be reversed for some functions, but I do not remember which ones.

It have been over sixty years ago since I last touch this instrument, so I really cannot be sure of the operations and functions that it provided. Sorry that I cannot be of more help."



Sun Hemmi No.22

ISRM 18.05.01.01
Sun Hemmi No.22 date code EJ (1954)
Made in Japan - Oct 1954
Note: a single stator and matching bamboo slide in a metal frame. 9 inches total length.
Front Scale: [ CI, C ] D, A
Gift of Giuseppe Bianchi of Italy


Sun Hemmi No.P23 8inch Plastic Slide Rule

ISRM 14.01.03.07
Sun Hemmi No.P23 8inch Plastic Slide Rule
Made in Japan - Reg507296
Front Scale: A [ B, CI, C ] D
Note: Left Brace was missing and original owner glued a fabricated part to hold it together.
Gift Of Phillip Rodley of Upper Hutt, New Zealand


Sun Hemmi No.P23 8inch Plastic Slide Rule (Version 2)

ISRM 14.01.03.07
Sun Hemmi No.P23 8inch Plastic Slide Rule (Version 2)
Made in Japan - Reg507296
Note: Math symbols on lens
Front Scale: A [ B, CI, C ] D
Original Owner: Janice Lingle (Marked on sleeve).
Gift Of James Pennell Collection


Hemmi-Westinghouse 4 inch

P192
Hemmi-Westinghouse 4 inch
Made in Japan by Sun Hemmi for Westinghouse (U.S.)
Front Scale: 4in || A [ B, CI, D || 10cm
Back Scale: [ S, L, T ]



Hemmi 30 w/ Magnifier 10cm

P223
Hemmi 30 w/ Magnifier
Made in Occupied Japan - Note: A and B scale missing π symbol at 3.14
Front Scale: 10cm // A [ B, CI, C ] D
Back Scale: [ S, L, T ]



Hemmi 30R w/ Magnifier 4in MIOJ
20.02.09.02
Hemmi 30R w/ Magnifier
Made in Occupied Japan - Note: A and B scale missing π symbol at 3.14
Front Scale: 10cm // A [ B, CI, C ] D
Back Scale: [ S, L, T ]
Gift of Barry J. Altman of Plymouth, Minnessota.
Belonged to Barry's uncle Robert N. Altman who worked with Square D and later with FMC's military division.


Hemmi 30 10cm

REF P254
Hemmi 30
Made in Japan - Note: A and B scale missing π symbol at 3.14
Front Scale: 10cm // A [ B, CI, C ] D
Back Scale: [ S, L, T ]



Hemmi 30 10cm (1964)

ISRM 22.07.06.75
Hemmi 30 10cm scale dcOA 1964
Made in Japan
Front Scale: 10cm // A [ B, CI, C ] D
Back Scale: [ S, L, T ]
Gift of Cindy Tate, Bozeman, Montana. Victor B. Tate collection.


Hemmi 30 w/ Magnifier 10cm

REF P143
Hemmi 30 w/ Magnifier
Made in Japan
Front Scale: 10cm // A [ B, CI, C ] D
Back Scale: [ S, L, T ]



Hemmi 30 SKF 10cm (1962)

REF P139
Hemmi 30 SKF
Made in Japan - Date Code MD (Apr, 1962)- Metal Cursor
Front Scale: 10cm // A [ B, CI, C ] D
Back Scale: [ S, L, T ]



Hemmi 30 10cm (1966)
ISRM 18.07.16.03


Hemmi 30 10cm
Made in Japan - Date Code QL (Dec, 1966)- Plastic Cursor
Front Scale: 10cm // A [ B, CI, C ] D
Back Scale: [ S, L, T ]
Back: Hitachi Promo Owned by Arnold D. Strausman, gifted by his daughter Judith B. King of Miami Shoes, Florida.
Arnold Davidson Straussman (c1908-1983) was an electrical engineer who loved the elegance of math, as well as science and the arts. After graduating from Pratt Institute, NY in 1929, he was employed by the Jersey Central Power and Light Company until 1940. The majority of his career was spent with Ebasco Services headquartered in NY. Ebasco assigned him to a number of domestic and overseas projects. He won numerous awards in Ebasco's Photography Club competitions. His daughter, Judith King write: "He was an amazing man, and introduced me to astronomy and Scientific American as soon as I could read. He loved math in its pure forms, but also the practicalities of what you could design and build with it. We designed and built a simple radio together before I was out of grade school. " Note: He is listed in Amatuer Radio Stations of the United States June 30, 1920: Call sign: 2AUH (18 watts), located at 601 Asbury Ave, Asbury Park, NJ. Evidently Arnold was building radios while still in high school. This was before W and K prefixes were to call signs in the USA.


Hemmi 32 w/ Magnifier 4inch

P141
Hemmi 32 w/ Magnifier
Made in Occupied Japan
Front Scale: 4in // A [ B, CI, C ] D
Back Scale: [ S, L, T ]



Hemmi 32 w/ Magnifier 4inch (1952)

ISRM 22.03.01.81
Hemmi 32 w/ Magnifier
Made in Japan - dcCI (September, 1952)
Front Scale: 4in // A [ B, CI, C ] D
Back Scale: [ S, L, T ]
Gift of Philip E. Stanley Collection


Hemmi 34 RK

P177
Hemmi 34 RK
Made in Japan - Early Cursor
Front Scale: 14cm // A [ B, CI, C ] D, K
Back Scale: [ S, L, T ]



Hemmi 34 RK (1955)

ISRM 22.03.01.80
Hemmi 34 RK dcFI (Sep. 1955)
Made in Japan - Metal Framed cursor
Front Scale: 5in // A [ B, CI, C ] D, K
Back Scale: [ S, L, T ]
Gift of Philip E. Stanley Collection



Hemmi 35ML w/ Magnifier 4in/10cm

22.07.06.74
Hemmi 35ML w/ Magnifier 4in/10cm
Note: Previously, slide rule was a model 16. Ref: Paul Ross Front Scale: 4in || A [ B, C ] D || 10cm
Back Scale: [ S, L, T ]
Gift of Cindy Tate, Bozeman, Montana


Hemmi 34RK (rebranded as Post 1444K ) MIOJ 1945-1952
ISRM 14.01.10.03
Hemmi 34RK (rebranded as Post 1444K ) MIOJ
Made in Occupied Japan - "Made In Occupied Japan" (MIOJ) is a term used for the time period from 1945 (after World War II) through April 25, 1952; it was during this time that the Allies "occupied" Japan.
Front Scale: 5 inch // A [ B, CI, C ] D, K
Back Scale: [ S, L, T ]
Advertisement (on sleeve): Keyes Tank company, Provo, Utah.
Gift Of Bill Wehrend Collection, Palo Alto, California.


Hemmi 34 RK

P136
Hemmi 34 RK
Made in Japan - Late model Cursor
Front Scale: 14cm // A [ B, CI, C ] D, K
Back Scale: [ S, L, T ]



Hemmi P36 Metric Converter (Japanese)

REF
Hemmi P36 Metric Converter (Japanese Language)
Made in Japan - All plastic
Archive - eBay photo



Sun Hemmi P37 Commerce "Sales" logo

ISRM 22.03.01.66
Sun Hemmi P37 Commerce "Sales" logo
Made in Japan - Plastic Japanese Kanji language fonts
Front Scale: (1)%, (2)%, D [ C, CI, 180 Days ] Months 1-6, Months 7-12
Back Scale: [ 4 scales ] (Reverse slide to use)
Promo: Sales.
Gift Of Philip E. Stanley collection


Hemmi 40 Occupied Japan

S261
Sun Hemmi 40 Occupied Japan
Made in Occupied Japan - Bamboo
Front Scale: A [ B, C ] D
Back Scale: [S, L, T]
Back: Conversions



Hemmi 40RK (1969) Bamboo

ISRM 15.05.09.07
Hemmi 40RK dc T.A. Jan. 1969
Made in Japan - Bamboo stock and slide
Front Scale: A [ B, CI, C ] D
Back Scale: [S, L, T]
Gift of Dick Rose



Hemmi P40RK (1969) Plastic

ISRM 15.05.09.06
Hemmi P40RK dc T.H. dc T.H. Aug. 1969
Made in Japan - Plastic Duplex styling
Front Scale: A [ B, CI, C ] D
Back Scale: [S, L, T]
Gift of Dick Rose



Sun Hemmi 45K 8"

S060
Sun Hemmi 45K 8"
Made in Japan - Bamboo
Front Scale: K, DF [ CF, CI, C ] D, A
Back Scale: [TI, L, SI]
Back: Conversions



Sun Hemmi Model 47

ISRM 12.11.22.03
Sun Hemmi Model 47
Made in Japan - 1936 - WWII
Front Scale (with Quot., Prod. Decimal tracking aids)
27cm // A [ B, C ] D || 10in
Back Scale (S keyed to A, B):
[ S, L, T ]
Note: Same as Hemmi model 1, Hemmi changed their numbering system about 1927
Donated from the collection of Robert L. Allison of Ballard, Washington.
Cardboard case


Sun Hemmi Model 47 (Export Version)

REF
Sun Hemmi Model 47 (Export version)
Made in Japan - c1930
Front Scale: 10 in // [ CI, C ] D, A || 29cm
Back Scale: [ S, L, T ]
Well: 30-55cm
Note: Same as Hemmi model 1, Hemmi changed their numbering system about 1927
Archive - Scan donated by Olivier (France)


Sun Hemmi No. 50/1 Advanced Mannheim 1928

ISRM 22.07.06.83
Sun Hemmi No. 50/1 Advanced Mannheim 1928
Made in Japan by sun Hemmi
Front Scale: 10in // A [ B, CI, C ] D, K || 28cm
Back Scale: [ S, L, T ]
Well: 30-55cm
Gift ofCindy Tate of Bozeman, Montana. Victor B. Tate collection.


Sun Hemmi No. 50W Mannheim Variant 1 (1959)

ISRM 14.01.10.28
Sun Hemmi No. 50W Mannheim Variant 1
Made in Japan date code JD (April, 1959)
Front Scale: 27cm // A [ B, CI, C ] D, K || 10in
Back Scale: [ S, L, T ]


Sun Hemmi No. 50W Mannheim Variant 2 (1960)

ISRM 13.08.12.06
Sun Hemmi No. 50W Mannheim Variant 2
Made in Japan date code KC.N (March, 1960)
Front Scale: 10in // A [ B, CI, C ] D, K || 27cm
Back Scale: [ S, L, T ]
Original Owner: K,S.Richmond,
Gift Of Phillip Rodley, Upper Hutt, New Zealand.
Inst (21.7MB PDF)


Sun Hemmi No. 50W Mannheim Variant 3 (1960)

ISRM 14.01.10.29
Sun Hemmi No. 50W Mannheim Variant 3
Made in Japan date code KK (Nov, 1960)
Front Scale: 27cm // A [ B, CI, C ] D, K || 13-0-13cm
Back Scale: [ S, L, T ]
Gift Of Phillip Rodley, Upper Hutt, New Zealand.


Sun Hemmi 64 with early "C" Cursor

ISRM 21.03.29.01
Sun Hemmi 64 with early "C" Cursor
Made in Japan - Bamboo Rail Road Track scales early "C" cursor.
Front Scale (extended): 27cm // K, A [ B, CI, C ] D, L || 10inch
Back Scale:: [ S, S&T, T ]
Back: Conversions, gauge marks (English).
Multiple Hairlines.


Sun Hemmi 64 Occupied Japan (Modern Cursor)

ISRM 13.11.05.03
Sun Hemmi 64 Occupied Japan (Modern Cursor)
Made in Occupied Japan - Bamboo
Front Scale (extended)
27cm // K, A [ B, CI, C ] D, L || 10inch
Back: Conversions, gauge marks. (too faded to read)
Multiple Hairlines.
Gift Of Phillip Rodley and Lew Solomon of New Zealand.

Cardboard case with logo and price tag ¥1250 Yen


Sun Hemmi 64 System Rietz (1958)

ISRM 13.11.05.03
Sun Hemmi 64 System Rietz dcIG (July 1958)
Made in Japan - Bamboo
Front Scale (extended)
27cm // K, A [ B, CI, C ] D, L || 13cm-0-13cm
Back: Conversions, gauge marks.(English)
Multiple Hairlines.
Gift Of Ted Hume, San Angelo, Texas.


Sun Hemmi 64T
Sun Hemmi 64T
Made in Japan - Bamboo. Note additional scales from other Hemmi 64s
Front Scale (extended)
27cm // K, A [ B, BI, CI, C ] D, DI, , L || 10inch
Back Scale: [T2 Cot2, , T1 Cot1, , S&T, S Cos, ]
Back: Conversions, gauge marks
Multiple Hairlines.
Archive - Herman van Herwijnen's SRC 24401


Sun Hemmi 65

ISRM 17.05.02.31
Sun Hemmi 65 (c1932-1968)
Note: Also shown in Hemmi gallery
Made in Japan - for Lutz, Ferrando Y Cia, S.A., Buenos Aires.
Note:Bamboo. Note Nestler Eqivalents Label And a Ricoh Cursor
Front Scale (extended)
27cm // K, A [ B, BI, CI, C ] D, L || 10inch
Back Scale: [ S, S&T, T ]
Back: Back: Nestler Equivalents slip in Portugese


Sun Hemmi 66 Rietz "C" cursor (c1932)

ISRM 22.03.01.64
Sun Hemmi 66 Rietz "C" cursor (c1932)
Made in Japan - Bamboo - No Date Codes
Front Scale (extended)
15cm // K, A [ B, CI, C ] D, L || 6in (finely divided)
Back Scale: [S, S&T, T]
Back: Missing Conversions insert
Multiple 3-Hairlines lens.
Promo: SKF ball bearings logo on sleeve.


Sun Hemmi 66 Rietz

REF
Sun Hemmi 66 Rietz
Made in Japan - Bamboo - Date Codes: LG HD
Front Scale (extended)
15cm // K, A [ B, CI, C ] D, L || 8cm-0-8cm
Back Scale: [S, S&T, T]
Back: Conversions, gauge marks
Multiple Hairlines.
Scan donated by the Owner, Dr. H. John Krijnen, (1946- ) Netherlands, a retired Anesthesiologist and pain specialist who studied at Leiden University. He bought and used slide rules like this one in his practice to calculate dosages of various drugs. He has published two books on the Great War and maintains an interest in slide rules, photography, markmanship and painting.


Sun Hemmi 74 System Rietz - Kanthal Promotional

S243
Sun Hemmi 74 System Rietz - Kanthal Promotional
Made in Japan - Bamboo - has brass stock spacer
Front Scale (extended)
14cm // K, A [ B, CI, C ] D, L
Back Scales: [ S, S&T, T ]
Multiple Hairlines.


Sun Hemmi 80/1 Electro

S410
Sun Hemmi 80/1 Electro
Made in Japan - Bamboo
Front Scale (extended)
27cm // K, A [ B, CI, C ] D, L || 10inch
Back Scale: Conversions, gauge marks
Well Scale: Dynamo/Motor (Efficiency), Volt (Drop)
Note: the aluminum knife edge on the slide and the backing have
been corroded away. This was found in Beijing, China.

Archive - No longer in collection


Sun Hemmi 80/3 Electro

REF
Sun Hemmi 80/1 Electro
Made in Japan - Bamboo
Front Scale (extended)
27cm // K, A [ B, CI, C ] D, L || 10inch
Back Scale: [ S, L, T ]
Back : Label Missing
Well Scale: Dynamo/Motor (Efficiency), Volt (Drop)
Scan provided by Olivier Cassou Collection, France


Sun Hemmi No. 80K Electro with Dual Cursors

ISRM 13.04.26.04
Sun Hemmi No. 80K Electro with Dual Cursors
Made in Japan - Bamboo date code FL (Dec 1955)
Front Scale (extended)
10inch // Dynamo/Motor, Volt, Amp/KW (A) [ PS (B), CI, C ] D, LL2, LL3 || K
Back Scale: [ S, L, T
Back: Conversions, gauge marks
Well: Blank
Note: The left cursor is used for metric HP horsepower, the right cursor used for British/US HP
Gift of Phillip Rodley, Upper Hutt, New Zealand



J.Hemmi "Sun" Model 81 Electro with Decimal Keeper
ISRM 12.06.23.02
J.Hemmi "Sun" Model 81 Electro with Decimal Keeper
Made in Japan -
Stock Patents:Patent 22129 (1912), British patent 107562 (1917), Brevete S.G.D.G.
Cursor Patent 58115 (1912). Cursor marked "Hemmi" so was installed 1928 or later. This was Hemmi's top-of-the-line cursor and was available from 1925 to WWII
Note: This is signed by "J.Hemmi". After 1928, the slide rules were just signed "Hemmi"
Front Scale: 27cm // LL2, A(KW) [ B(HP), CI, C ] D, LL03 || 10 in
Back Scale: [ S, L, T ]
Well: Dynamo(Motor), Volt
Gift of Jiro Higuchi, Kamakura, Japan
This slide rule was owned by Jiro's father who was an electrical engineer. "Jiro" means "second son" in Japanese. Jiro worked in a career at Daicel Chemical Industries, Ltd As a vice-president, he worked with many American companies that were developing writable optical disk media.


J.Hemmi "Sun" Model 82 (1932-1937)
ISRM 21.11.24.01

Note: This is signed by "J.Hemmi". After 1928, the slide rules were just signed "Hemmi"
J.Hemmi "Sun" Model 82 150mm Pocket (1914-1929)
Made in Japan by J. Hemmi, Railroad Track scales, metal framed cursor
On lower edge of stock: Patent No. 22129 (1912). British Patent 107562 (1917),. Brevete S.G.D.G. Made in Japan.
Front Scale: 5 in // A [ B, C ] D || 15cm
Back Scale: [ S, L, T ]
Well: 16cm - 30cm
Back: Equivalents in English
Gift Of Graham L. Jones of Cambridge, UK
Graham L. Jones studied agricultural sciences and economics at university, followed by 2 years of compulsory National Service in the Army. He was fortunate to be commisioned and after 2 years he transferred to the Army Reserve and served as a troop commander in a volunterr BD Regiment in the Royal Engineers. His career spanned 34 years with the Agricul;tural Development and Advisory Service. Toward the end of his career he was appointed to the British Embassies in Denmark and Norway as First Secretary Agriculture and Fisheries for 4 years. He retired in 1983


Sun Hemmi No. 130 System Darmstadt

ISRM 13.08.12.04
Sun Hemmi No. 130 System Darmstadt
Made in Japan - Bamboo, Simplex design
Note 'Railroad Track' style divisions
Front Scale (extended)
27cm // K, A [ B, BI, CI, C ] D, DI, , L || 10inch
Back Scale: [T2 Cot2, , T1 Cot1, , S&T, S Cos, ]
Back: Conversions, gauge marks
Multiple Hairlines.
Gift of Phillip Rodley, Upper Hutt, New Zealand
Cardboard Case


Hemmi 130W Advanced Darmstadt (c1970)

REF
Hemmi 130W Advanced Darmstadt
Made in Japan by Hemmi.
Front Scale: 10in // T Cot, K, A [ B, BI, CI, C ] D, P, S Cos || 27cm
Back Scale: [ L, LL0, LL1, LL2, LL3 ]
Back: Equivalents
Scan provided by Olivier Cassou Collection, France


Hemmi No 135 Pocket Darmstadt (1959-1971)

REF
Hemmi 135 Pocket Darmstadt
Made in Japan by Hemmi.
Front Scale (extended)
T Cot, K, A [ B, CI, C ] D, P, S Cos
Back Scale: [ L, LL1, LL2, LL3 ]
Back: Equivalents
Scan provided by Olivier Cassou Collection, France


Hemmi No 136 Pocket System Darmstadt (1959)
ISRM 22.03.01.12
Hemmi 136 Pocket System Darmstadt dcJFA (June_1959)
Made in Japan by Hemmi.
Front Scale (extended)
15cm // T, K, A [ B, CI, C ] Sin(D), Cos || Cos Cot , Tg Cot
Back Scale: [ LL1, LL2, LL3 ]
Back: Equivalents(English)
Gift Of Philip E. Stanley Collection


Hemmi 143 Commerce

REF
Hemmi 143 Commerce
Made in Japan by Hemmi.
Front Scale: A, N [ M, £, s/d, C ] D, G (Conversions)
Back Scale: P1 %, P2 %, DF [ CF, CIF, CI, C ] D, LL, %
Archive - Herman van Herwijnen's SRC 56771


Hemmi 149 Pocket Duplex Log Log (1961)

ISRM 22.03.01.65
Hemmi 149 Pocket Duplex Log Log dcLH Aug. 1961
Made in Japan by Hemmi.
Front Scale: L, K, A [ B, TI Cot, SI Cos, C ] D, LL0, LL/0
Back Scale: LL/1, LL/2, LL/3, DF [ CF, CIF, CI, C ] D, LL3, LL2, LL1
Gift Of Philip E. Stanley


Hemmi 149A

REF
Hemmi 149A
Made in Japan by Hemmi.
Front Scale: L, K, A [ B, TI Cot, SI Cos, C ] D, LL0, LL/0
Back Scale: LL/1, LL/2, LL/3, DF [ CF, CIF, CI, C ] D, LL3, LL2, LL1
Archive - Herman van Herwijnen's SRC 24661


Sun Hemmi 153 (early)

ISRM 12.04.23.02
Sun Hemmi 153 (early) - For Electrical Engineer
Made in Japan - No Date code
Note: Scale labels use Times Romans font.
Front Scale: L, K, A [ B, CI, C ] D, T, Gθ
Back Scale: θ, Rθ, P(sin) [ Q(cos), Q', C ] LL3, LL2, LL1
Donated By Jim Jeffery, California
Note: This is pre WW-II version as there is no model number on the stock and the label fonts are different than later versions (look at the 'I' in CI on the other Hemmi 153's). Also the Q' scale on this model is red, the others are black.


Sun Hemmi 153 (Pre WWII)

ISRM 14.10.09.05
Sun Hemmi 153 (Pre WWII) - For Electrical Engineer
Made in Japan - No Date code. Note logo on cursor, pre-"Occupied Japan"
Front Scale: L, K, A [ B, CI, C ] D, T, Gθ
Back Scale: θ, Rθ, P(sin) [ Q(cos), Q', C ] LL3, LL2, LL1
Gift Of Edward Wright, Odenton, Maryland.
Hemmi 153 and Special Scales Instructions


Sun Hemmi 153 Occupied Japan

ISRM 12.06.18.03

Sun Hemmi 153 Occupied Japan - For Electrical Engineer
Made in Japan - Purchased in Nagasaki, 1949
Front Scale: L, K, A [ B, CI, C ] D, T, Gθ
Back Scale: θ, Rθ, P(sin) [ Q(cos), Q', C ] LL3, LL2, LL1
Note: Engraved with "Occupied Japan", no other date code. Japan was occupied by the U.S. Armed Forces September 1945 and the treaty to un-occupy was September 1951, becoming effective April 1952.
This slide rule was put on eBay by RAdm Rhoad's grandson. It was purchased and Donated By Rod Vance of Australia, Friend of the Museum.
This slide rule was purchased by Rear Admiral Forrest (Dusty) Rhoads while on assignment in Nagasaki, Japan in 1949. Prior to WW-II he owned a Dietzgen 1740 which can be seen in the Dietzgen Gallery.

Forrest Alexis Rhoads (1898-1965) was a career naval officer in the United States Navy and his career spanned from an Apprentice Seaman to Rear Admiral and he served in both WWI and WWII. The pictures show him in rank from apprentice Seaman (on left, 1916 on the USS South Dakota), Seaman 1st Class (on left, c1920), Captain (1947), Rear Admiral (on right, 1949) and his final promotion at the National Memorial Cemetary in Honolulu, Hawaii (1965). See an expanded biography at ancestry.com.


Sun Hemmi 153 For Electrical Engineer

ISRM 12.06.24.09

During his time at Harvard, when he used this slide rule, Bill was in the "Folksingers 'Round Harvard Square" with Joan Baez, when she was 18, along with Ted Alevizos. At graduation, Bill traveled to Palo Alto, California to continue studies at Stanford. Joan Baez continued her singing career by traveling to the 1959 Newport Folksong Festival.
Sun Hemmi 153 For Electrical Engineer
Made in Japan. Note arrangement of Model number and Logo. No date code.
Front Scale: L, K, A [ B, CI, C ] D, T, Gθ
Back Scale: θ, Rθ, P(sin) [ Q(cos), Q', C ] LL3, LL2, LL1
Originally belonged to William (Bill) Barry Woods III, used at Harvard, Cambridge, Mass.

Bill Wood is a Distinguished Professor Emeritus at the University Of Colorado, Boulder. His specialty is in Molecular, Cellular & Developmental Biology. The son of a scientist, Dr. William Barry Wood Jr.(1910-1971), Bill received his A.B. in Chemistry at Harvard, his father and grandfather's alma mater, in 1959. Bill then received his Phd in BioChemistry at Stanford in 1963.In 2014, William B. Wood received the Arthur Kornberg and Paul Berg Lifetime Achievement Award, Stanford University Medical School.


Sun Hemmi 153 (1961)

ISRM 12.06.24.09
Sun Hemmi 153 - For Electrical Engineer
Made in Japan - Date code LI (Sep 1961)
Front Scale: L, K, A [ B, CI, C ] D, T, Gθ
Back Scale: θ, Rθ, P(sin) [ Q(cos), Q', C ] LL3, LL2, LL1
Donated by Anonymous collector and daughter.
The collector, who prefers to remain anonymous, obtained a B.S. degree in Physics from Taiwan's National Tsing Hua University in 1971. His love for computation has encouraged him to build a collection of slide rules, HP and TI calculators, as well as abaci, many displayed at ISRM.


Hemmi 250 Basic Trig (1953)

ISRM 21.08.07.05
Sun Hemmi 250 Basic Trig
Made in Japan - Date Code DE (May 1953)
Note: Alternat DF scale labeling and cursor bar.
Front Scale: K, A [ B, TI2 Cot, TI1 Cot, SI Cos ] D, DI
Back Scale: DF [ CF, CIF, CI, C ] D, L
Gifted by William Lisowski of Pennsylvania


Hemmi 250 Basic Trig (1962)

ISRM 18.04.06.130
Sun Hemmi 250 Basic Trig
Made in Japan - Date Code MH (August 1962)
Front Scale: K, A [ B, TI2 Cot, TI1 Cot, SI Cos ] D, DI
Back Scale: DF [ CF, CIF, CI, C ] D, L
Original Owner: Jane Warner (marked on sleeve flap)
Gifted by Leroy Hausler Collection



Hemmi 251 for Mechanical Engineer (1951)

S325
Sun Hemmi 251 - For Mechanical Engineer
Made in Japan - Date Code BC (March 1951)
Front Scale: K, A [ B, T Cot, S Cos, ST, C ] D, LL3, LL2, LL1
Back Scale: L, DF [ CF, CIF, CI, C ] D, DI



Sun Hemmi 251 for Mechanical Engineer MIOJ (1953)

ISRM 15.02.28.01
Sun Hemmi 251 for Mechanical Engineer MIOJ
Made in Occupied Japan - Date Code DC (March 1953)
Front Scale: K, A [ B, T Cot, S Cos, ST, C ] D, LL3, LL2, LL1
Back Scale: L, DF [ CF, CIF, CI, C ] D, DI
Note: MIOJ marking were from August 1945 until April 28, 1952


Sun Hemmi 251 for Mechanical Engineer (1960)

ISRM 15.11.03.01


Sun Hemmi 251 - For Mechanical Engineer
Made in Japan - Date code KJ (Oct 1960)
Front Scale: K, A [ B, T Cot, S Cos, ST, C ] D, DI
Back Scale: L, DF [ CF, CIF, CI, C ] D, LL3, LL2, LL1
Note different scale set ( DI,LL3, LL2, LL1) and logo position than the 1951 version above.
Donated By Randy Rash in memory of his father Charles (Chuck) Elmer Rash (1918-1989) of Portland, Oregon.
Randy writes about his father: "I have all his flight logs and am still staggered by all the different aircraft he flew during his career. The majority involve seaplanes during World War 2 used for submarine hunting and later after the Korean War he flew helicopters. Also with the express purpose of sub hunting. He started in the Navy as a rear gunner/radio man in the Douglas Dauntless and similar aircraft. He was what I believe was considered a "Mustang Officer". He started out as enlisted and later gained officer status after becoming a pilot. One interesting thing was he spent some time teaching Air Force pilots to land on aircraft carriers using the North American T-28 Trojan."
There are two other slide rules used by Chuck Rash, and more pictures, shown in the Pickett, Circular and Aerospace galleries.


Hemmi 255 Expert Electrical Engineer

ISRM 21.02.02.01
Sun Hemmi 255 - For Expert Electrical Engineer
Made in Japan by Sun Hemmi - Date code ID Apr1958
Front Scale: Sh1, Sh2, Th, A [ B, TI2, TI1, S1, C ] D, χ, θ
Back Scale: L, K, DF [ CF, CIF, CI, C ] D, LL3, LL2, LL1
Original Owner: Gjovig (etched on brace)


Hemmi 255

S071
Sun Hemmi 255 - For Expert Electrical Engineer
Made in Japan - Date code EF- Had US Gov't on it
Front Scale: Sh1, Sh2, Th, A [ B, TI2, TI1, S1, C ] D, LL3, LL2, LL1
Back Scale: L, K, DF [ CF, CIF, CI, C ] D, χ, θ
Original Owner/Location: K.Fooshee/USA



Hemmi 255D Expert Electrical Engineer (1966)

ISRM 22.04.09.02
Sun Hemmi 255D - For Expert Electrical Engineer
Made in Japan - Date code QB 1966 - rearranged scales
Front Scale: Sh1, Sh2, Th, A [ B, TI2 Cot2, TI1 Cot1, SI Cos, C ] D, DI, χ, θ
Back Scale: L, K, DF [ CF, CIF, CI, C ] D, LL3, LL2, LL1
Gifted by Phillip Rodley of Upper Hutt, New Zealand.



Hemmi 256 - For Radio Communications (1953)

ISRM 14.01.09.01

Sun Hemmi 256 - Radio Communications
Made in Japan - for the Electronic Engineer - Date code DG (1953)
Front Scale: A, L [ C, S1, T1 ] D, λ, F
Back Scale: L, db, Neper, DF[ CF, CIF, CI, C ] D, LL3, LL2, LL1
Original Owner: Arthur McCusker.
Gifted by his step-daughter, Jodie Adams, and grandson, Jason Adams, of Boise, Idaho.
Arthur Eugene McCusker (1931-2013) used this slide rule (and the Hemmi 2634 in the gallery, most likely purchased while in Japan) during his 30 year career in the U.S. Navy. He entered the Navy as a Seaman Recruit in 1950 and retired in 1980 as a Commander. He served during the Korean and Vietnam conflicts. After his military retirement Arthur was employed for 10 more years by San Diego defense contractors working on electronic warfare systems. He lived in Las Vegas, then relocated to Boise, Idaho where he became very active in his Parish.


Hemmi 256 - For Radio Communications (1953)

ISRM 17.08.24.01

Sun Hemmi 256 - Radio Communications
Made in Japan - for Electronic Engineers - Date code LC (march 1961)
Front Scale: A, L [ C, S1, T1 ] D, λ, F
Back Scale: L, db, Neper, DF[ CF, CIF, CI, C ] D, LL3, LL2, LL1
Original Owner: Dustin E. Morris of Tempe, Arizona
Gifted by his wife, Nancy Morris, of Tempe, Arizona. who gifted the Dustin Morris Collection to ISRM.

Dustin E. Morris (1939-2017) Dustin, shown in this photo, holdin his father's slide rule next to a Navy ship model. His father was a Naval engineer, so he started out young using a slide rule. He enlisted in the Coast Guard after high school where he started his career in electronics. Dusty worked for Motorola in the Phoenix area for 33 years. He went to ASU in the evenings until he earned his engineering degree. Dusty was a ham radio operator W7ITM who enjoyed building his own equipment. He was an active member of the Motorola Amateur Radio Club of Arizona (MARCA) He presented "Home Brew SWR Bridge" during his last year at age 78. Of the mmany slide rules donated to ISRM, by his wife, Nancy, this is one he used quite often in his Amatuer radio hobby. You can see his other personal slide rule, A Pickett N800-ES Log Log and others from his collection in the ISRM galleries.


Hemmi 257 for Chemical Engineer

ISRM 12.06.23.01

Sun Hemmi 257 - For Chemical Engineer
Made in Japan by Sun Hemmi
Front Scale: L, A, DF [ CF, CIF, CI, C ] D, LL3, LL2, LL1
Back Scale: Ch(A~M), Ch(N~Z), M1 Xw [ M2 X, Temp(F,C,K)°, F(t) ] Kg/cm2, P mmHg Atm, P inHgVac Lb/in2 Gage , tω °C

Jiro Higuchi Signature
Owned and donated donated by Jiro Higuchi, Kamakura, Japan
Jiro used this as an chemical engineering student and later when working in a career at Daicel Chemical Industries, Ltd As a vice-president, he worked with many American companies that were developing writable optical disk media.

Brief 257
Instructions
Brian C.
Cunningham
Collection
Jiro Higuchi was a past business associate, and a good friend of Mike Konshak, the ISRM curator, who has visited his home in Japan. Jiro shares this humorous story about sorobans (Japanese abacus) vs slide rules: "Here was a funny story. My brother in law is a wholesaler of eggs in Tsukiji which is very famous market to deal fresh fish in Tokyo. At the end of year it was very busy because many people came to buy foods for the New Year' days. One day, around forty five years ago (about 1972), I helped him to sell eggs at the shop. Usually the eggs are sold piece by piece, but at the market it was sold by kilo. That means the weight of each 10 eggs is different and the price must be calculated each time. They used soroban for the calculation, but I was not able to use soroban for multiplication. Then I brought my slide rule and used it, it was very fast, but many people did not trust my result. Probably I would be the first person to use a slide rule at the Tsukiji market."


REF Hemmi 257L
Sun Hemmi 257L - For Chemical Engineer
Made in Japan by Sun Hemmi
Note: Back scales on lower slide and stator slightly different than the 257
Front Scale: L, K, A, DF [ CF, CIF, CI, C ] D, LL3, LL2, LL1
Back Scale: Ch(A-M), Ch(N-Z), M1 Xw [ M2 X, T (°F,°C,°K), LM a/b, LM a:b ] mm hg atm., Kg/cm2, in.Hg.Vac. lb/in2 gage, tω °C
Archive - Peter Owen Collection


Hemmi 258 (Post 1460 Versalog) 1951

ISRM 09.01.12.30
Hemmi 258 (Post 1460 Versalog)
Made in Japan by Hemmi - Date code BA - March 1951
Front Scale: LL/1, LL/2, LL/3 [ T/T, SecT/ST, Cos/S, C ] D, LL3, LL2, LL1
Back Scale: LL0, LL/0, K, DF [ CF, CIF, CI, C ] D, R1, R2, L
Note: Cos label printed in Black. This is the first and only version where Hemmi 258 appears on a Post Versalog
Donated by David Hecht, New York


Hemmi 259 Mechanical Engineer (1953)

ISRM 14.10.11.02.X (Deaccessioned 8/23)
Sun Hemmi 259 - For Expert Mechanical Engineer dcDK (Nov 1953)
Made in Japan - 26 scales
Front Scale: L, K, A [ B, T Cot, S Cos , ST Cos, C ] D, LL0, LL/0
Back Scale: LL/1, LL/2, LL/3, DF [ CF, CIF, CI, C ] D, LL3, LL2, LL1


Hemmi 259 Mechanical Engineer (1954)

ISRM 19.05.04.06
Sun Hemmi 259 - For Expert Mechanical Engineer dcDK (March 1954)
Made in Japan - 26 scales - Note the Revision 2 scale set differences.
Front Scale: L, K, DF [ CF, CIF, CI, C ] D, LL0, LL/0
Back Scale: LL/1, LL/2, LL/3, A [ B, T Cot, S Cos , ST Cos, C ] D, LL3, LL2, LL1
Gift of the Terry Whitsel Collection, Loveland, Colorado


Hemmi 259-D Expert Mechanical Engineer dc-MB (1962)

REF S358
Sun Hemmi 259 For Expert Mechanical Engineer
Made in Japan - date code MB (Feb 1962)
Note: Added "DI" scale.
Front Scale: L, K, A [ B, T Cot, S Cos , ST Cos, C ] D, DI, LL0, LL/0
Back Scale: LL/1, LL/2, LL/3, DF [ CF, CIF, CI, C ] D, LL3, LL2, LL1
Original Owner: George Ingram, Houston, Texas. U.S.A. Graduate of Texas A&M University. George received this as a gift from his parents who ordered it with his name engraved on it through Edmund Scientific. He used this for performing Fast Fourier Transforms Calculations in the 1960's and 1970's by hand. As of 2011 he is a Computer Scientist in Columbia, Missouri.


Hemmi 259D Expert Mechanical Engineer (1969)

ISRM 22.05.06.18
Sun Hemmi 259D - For Expert Mechanical Engineer
Made in Japan - date code TC (March 1969)
Front Scale: L, K, A [ B, T Cot, S Cos , ST Cos, C ] D, DI, LL0, LL/0
Back Scale: LL/1, LL/2, LL/3, DF [ CF, CIF, CI, C ] D, LL3, LL2, LL1
Gift Of Nancy Ulrich. Husband Ted Ulrich's Collection


Hemmi 259D-S Expert Mechanical Engineer (New Scale Set)

REF
Sun Hemmi 259D-S - For Expert Mechanical Engineer (New Scale Set) 1970
Made in Japan - date code UJ (Oct 1970)
Front Scale: LL0, LL/0, A [ B, T Cot, S Cos , ST Cos, C ] D, √1, √2, L
Back Scale: LL/1, LL/2, LL/3, DF [ CF, CIF, CI, C ] D, LL3, LL2, LL1
Archive - Scan provided by Trevor Dewey


Sun Hemmi 260 Advanced Engineer (1968)

ISRM 20.03.16.01
Sun Hemmi 260 Advanced Engineer dcSC May 1963
Made in Japan
Front Scale: LL/0, LL0, K, A [ B, T Cot, S Cos, ST, C ] D, DI, P, L
Back Scale: LL/1, LL/2, LL/3, DF [ CF, CIF, CI, C ] D, LL3, LL2, LL1
Gift of Catherine Young of Oak View, California,
Belonging to Catherine's grandfather, James Whittier Morrill who was an army chaplain and most likely bought the slide rule in Japan on one of his tours or traveling after retirement. Manual is in Japanese. The U.S. Senate Congressional Record shows he was promoted to Captain in 1953. (O66184).


Sun Hemmi P261 (1973)

ISRM 09.01.12.31
Sun Hemmi P261 dcXE
Made in Japan - date code XE (May 1973)
Front Scale: T Cot, ST ST, K, A [ B, BI, CI, C ] D, L, P, S Cos,
Back Scale: LL01, LL02, LL03, DF [ CF, CIF, CI, C ] D, LL3, LL2, LL1
Donated by David Hecht, Alexandria, VA


Sun Hemmi P262 (1973)

ISRM 09.01.12.32
Sun Hemmi P262 dcXG
Made in Japan - date code XG ( July 1973)
Front Scale: K, A R1, R2 [ T2 Cot2, T1 Cot1, ST ST, S Cos, C ] D, L, LL00, LL0
Back Scale: LL01, LL02, LL03, DF [ CF, CIF, CI, C ] D, LL3, LL2, LL1
Donated by David Hecht, Alexandria, VA


Hemmi 264 Log Log Decitrig (1968)

ISRM 21.03.22.01
Hemmi 264 Log Log Decitrig dcSI
Made in Japan - date code SI ( Sep 1968)
Front Scale: K, A [ B, TI2 Cot2, TI1 Cot1, SI Cos] D, L, LL1
Back Scale: LL3, LL2, DF [ CF, CIF, CI, C ] D, L, LL1


Hemmi 266 Electronics (May 1966)

ISRM 21.02.22.01
Sun Hemmi 266 Electronics - For Electronic/Radio Engineer
Made in Japan by Sun Hemmi dcQE May 1966
Front Scale: LL3-, LL2-, LL2 A [ B, BI, CI, L ] D, dB/L, S Cos, T Cot
Back Scale: XL, Xc, T1 [ T2, L, Xc, R, Tc, F, fm, y1, P, y2, Q, Cf, C, C, Cz ] L, Z, fo, λ

Note: Leather sleeve embossed as TAMAYA.


Hemmi 269 - Civil

REF
Sun Hemmi 269 - For Civil Engineer
Made in Japan
Front Scale: L, F, K, A [ B, K', CI, C ] D, LL3, LL2, LL1
Back Scale: CL, SL, M, TL [ R, ST COS-COT, , T COT, , S COS, , C ] D, DI, , SIN COS (1), SIN COS (2)
Archive - Herman van Herwijnen's SRC


Sun Hemmi P280 LogLog dcVF (1971)

ISRM 15.05.12.10
Sun Hemmi P280 LogLog dcVF (1971)
Made in Japan by Hemmi.
Front Scale: T Cot, K, A [ B, CI, C ] D, L, S Cos, ST ST
Back Scale: [ LL1, LL2, LL3 ]
Donated by Colin Barnes, United Kingdom


Sun Hemmi P281 (1970)

ISRM 14.02.10.03

Sun Hemmi P281 - date code UC (March 1970)
Made in Japan by Sun Hemmi
Front Scale: T Cot, K, A [ B, CI, C ] D, L, S Cos, ST ST
Back Scale: Blank.
Original Owner: Mary Northcote, England. Label on back of stock.
Gift of Jane Northcote, London, England, Mary Northcote's older sister.
Mary Northcote (1958-) musician. Mary used this slide rule for her Zoology degree at Oxford in the 1970s and 80s.

P280 and P281 Instructions 4.31MB PDF



Sun Hemmi P283 (c1973)

ISRM 09.01.12.34
Sun Hemmi P283
Made in Japan - c1973
Front Scale: K, A, DF [ CF, CI, C ] D, L, T Cot, S Cos
Back Scale: [ LL1, LL2, LL3 ]
Donated by David Hecht, Alexandria, VA


Hemmi P452 - Business, System H. Kroon

ISRM 09.01.12.35
Hemmi P452 - Business, System H. Kroon
Made in Japan - date code UC (Mar 1970)
Front Scale: LL1, LL2, LL3, CR DF [T CF, CIF, % CI, T C] R D, L, in, cm
Back Scale: ST, 3n-2 K, 2n-1 A [B, BI, CI, C] D, P, S, T
Donated by David Hecht, Alexandria, VA


Hemmi 2634 (Made in Occupied Japan)
ISRM 14.01.09.02
Hemmi 2634 - For General Engineer
Made in Occupied Japan
Front Scale: 5in // K, DF [ CF, CI, C ] D, A
Back Scale: [ TI1, TI2, L, SI1 ]
Original Owner: Arthur McCusker. Bio provided by his step-daughter, Jodie Adams, and grandson, Jason Adams, of Boise, Idaho.
Arthur Eugene McCusker (1931-2013) used this slide rule (and the Hemmi 256 in the gallery, most likely purchased while in Japan) during his 30 year career in the U.S. Navy. He entered the Navy as a Seaman Recruit in 1950 and retired in 1980 as a Commander. He served during the Korean and Vietnam conflicts. After his military retirement Arthur was employed for 10 more years by San Diego defense contractors working on electronic warfare systems. He lived in Las Vegas, then relocated to Boise, Idaho where he became very active in his Parish.


Sun Hemmi 2664 WWII era

ISRM 21.10.12.01
Sun Hemmi 2664 WWII Wartime era 1940-1945
Made in Occupied Japan - Celluloid laminated Bamboo construction, metal joint.
Note: Obround rear window ports for trig scales.
Note: Replaced damaged cursor from 50W, 80 or 300).
Front Scale: 27cm // K, DF [ CF, CI, C ] D, A+L || 10in
Back Scale: [ TI2, TI1,SI2, SI1 ]
Note: A+L scale is left half of A scale joined to right half of L scale.
Back: Conversion Chart missing (most likely it was in Japanese.)




Sun Hemmi No. 2664

ISRM 13.08.12.05
Sun Hemmi 2664
Made in Occupied Japan (MOIJ) - Celluloid laminated Bamboo construction, metal joint.
Front Scale: 10inch // K, DF [ CF, CI, C ] D, A \\ 27cm
Back Scale: [ TI2, TI1, L, SI1 ]
Back: Conversion Chart (English)
Gift of Phillip Rodley, Upper Hutt, New Zealand


Hemmi 2664S - For General Business

ISRM 14.01.03.04
Sun Hemmi 2664S - For General Business
Made in Japan - Celluloid laminated Bamboo construction, metal joint.
Front Scale: 10inch // K, DF [ CF, CIF, CI, C ] D, A \\ 27cm
Back Scale: [ TI2 Cot, TI1 Cot, L, S Cos]
Back: Conversion Chart, Weights of metals (English)
Original owner: M.W. Baker,(marked on cardboard sleeve), New Zealand?
Gift of Phillip Rodley, Upper Hutt, New Zealand


Foxboro Flow And Valve Rule (Hemmi)

ISRM 11.11.11.01
Foxboro Flow And Valve Rule (Hemmi)
Made in Japan
Front Scale: Flow Calculation
Flow Nozzle d/D, Quadrant Edge d/D, r/D, Flange d/D [ D, Gas T, p, G; Steam p; Liquid T, P, G ] Flow (Gas/Steam/Liquid), V
Back Scale: Control Valve, Reynolds Number
Liquid G, Re [ Fsh, D, Gas G, P, Flow (Gas/Steam/Liquid), psi ] Cv, Gas P2, Steam P2, V
Donated By Carlee Heit, Houston Texas, in Memory of her husband Ray Heit
See other Foxboro Valve Sizing Calculators in the MiscUSA gallery.


Hemmi P3526 - Basic Slide Rule

REF
Sun Hemmi P3526
Made in Japan - Plastic Slide Rule. 250 x40 x 3mm
Front Scale: S, K, A [ B, CI, C ] D, L, T
Back: Blank
Original owner: Found in Aukland, New Zealand
Scan by Paul Ross, Slide Rule Trading Co. Given to Paul by Phillip Rodley, Upper Hutt, New Zealand

Hughes-Owens/Geotec


Hughes-Owens 1762 MIOJ Pocket Manneheim
ISRM 18.07.11.09
Hughes-Owens 1762 MIOJ Pocket Manneheim c1947-1949
Made in Occupied Japan by Sun Hemmi for The Hughes-Owens Co. Limited.
Front Scale: A [ B, CI, C ] D
Back Scale: [ S, L, T ]
Back: Equivalents
Gifted by Phil Stanley of Worcster, Massachussettes


Hugh-Owens 1766 Electronic

ISRM 09.01.12.36
Hugh-Owens 1766 - Electronic
Made in Japan by Sun Hemmi
Front Scale: K, A [ B, CI, C ] D, T
Back Scale: θ, Rθ, P(sin) [ Q(cos), Q', C ] LL3, LL2, LL1
Donated by David Hecht, Alexandria, VA


S314 Hugh-Owens 1768 Mannhiem
Hugh-Owens 1768
Made in Japan by Hemmi for Canadian Distributor H-O
Front Scale: A [ B, C ] D
Back Scale: [ S, L, T ]



Hugh-Owens 1768C Mannhiem

ISRM 09.01.12.37
Hugh-Owens 1768C - date code PA (Jan 1965)
Made in Japan by Hemmi for Canadian Distributor H-O
Front Scale: A [ B, CI, C ] D, K
Back Scale: [ S, L, T ]
Donated by David Hecht, Alexandria, VA


Hugh-Owens 1768C Mannhiem

ISRM 09.01.12.37
Hugh-Owens 1768C - date code OL (Dec 1964)
Made in Japan by Hemmi for Canadian Distributor H-O
Front Scale: A [ B, CI, C ] D, K
Back Scale: [ S, L, T ]
Gift Of Nathalie Doiron, belonged to father Henri Doiron, Quebec, Canada
Henri Doiron (1933-2005) was born in Amherst Nova Scotia, Canada. He graduated from the University of New Brunswick in Fredericton in 1955 with a degree in biology, From 1959 to 1988 he taught mathematics, biology, chemistry and physics in Ontario high schools. This slide rule has a date code of 1964, so he may have used it alojng with his students.


Hughes-Owens 1771

ISRM 12.11.20.01
Hughes-Owens 1771
Made in Japan by Hemmi and rebranded by Hughes-Owens Co. Limited. - Date code JB - Feb 1959
Front Scale: 10in // A [ B, CI, C ] D, K || 27cm
Back Scale: [ S, L, T ]
Donated by Ron Dies,Vancouver, British Columbia, Canada
Ron Dies purchased and used this slide rule (see also his DIWA 851/4 pocket slide rule in the Nordic gallery) when he was studying architecture from 1956-1962 at the University of Manitoba in Winnipeg. He used these slide rules until electronic slide rules became more useful in his career. He is currently owner of Ron Dies Architecture in Vancouver and is near retirement.


Hughes-Owens 1777

ISRM 09.01.12.38
Hughes-Owens 1777 dcHK (Same as Post 1460 Versalog)
Made in Japan by Hemmi - Date code HK - Nov 1957
Front Scale: LL/1, LL/2, LL/3 [ T/T, SecT/ST, Cos/S, C ] D, LL3, LL2, LL1
Back Scale: LL0, LL/0, K, DF [ CF, CIF, CI, C ] D, R1, R2, L
Note: Cos label printed in Black
Original Owner: F. Schmidt
Donated by David Hecht, Alexandria, VA


Hughes-Owens 1777

ISRM 09.01.12.38



Photos from 1946 and 1969.
Hughes-Owens 1777 dcJF (Same as Post 1460 Versalog)
Made in Japan by Hemmi - Date code JF - June 1959
Front Scale: LL/1, LL/2, LL/3 [ T/T, SecT/ST, Cos/S, C ] D, LL3, LL2, LL1
Back Scale: LL0, LL/0, K, DF [ CF, CIF, CI, C ] D, R1, R2, L
Note: Cos label printed in Black
Original Owner: Mel L. Frost (Name on sleeve and book protector).
Gifted by his children, Les Frost and Marian Nurse of Kanata, Ontario, Canada
Merle Leslie (Mel) Frost (1923 - 2010).joined the Royal Canadian Air Force during the Second World War and trained as part of the British Commonwealth Air Training Plan as a Rigger/Fitter. He was then posted to Linton-on-Ouse in Yorkshire England where he was a member of 426 Thunderbird Squadron as a member of the ground crew on "L" Love one of the Halifax bombers operating out of the base. He met and married his wife, Jeannie Ferrell, in England, and was posted back to Canada at the war's end. He continued to serve after the war and was posted to a number of bases in Prince Edward Island, Manitoba, Zweibrucken Germany, and several bases in Ontario. Mel was also head of aircraft maintenance in Yemen during a United Nations mission keeping Canadian Caribou twin-engine STOL aircraft flying in desert conditions. While posted at Trenton Ontario, Canada's main Transport Command base where he was once again part of 426 Squadron between 1956 and 1966. While there he was a Sergeant, Flight Sergeant, and Flying Officer responsible for the maintenance and loading of the various aircraft in the fleet at that time. It was during this time that he purchased and used this slide rule in his supervisory role on the hangar line. He loaned it to his son for a time when Les was in high school.


Hughes-Owens 341-3010 (1968)

ISRM 09.01.12.39
Hughes-Owens 341-3010 dcSH (Same as Post 1460 Versalog)
Made in Japan by Hemmi - Date code SH - Aug 1968
Front Scale: LL/1, LL/2, LL/3 [ T/T, SecT/ST, Cos/S, C ] D, LL3, LL2, LL1
Back Scale: LL0, LL/0, K, DF [ CF, CIF, CI, C ] D, R1, R2, L
Note: Cos label printed in Green
Original Owner: F. Schmidt (inside window)
Donated by David Hecht, Alexandria, VA


Geotec 341-3012 Versalog II

ISRM 18.04.06.127
Geotec 341-3012 Versalog II (Same as Post 1460 Versalog II)
Made in Japan by Hemmi - Date code: WF (June 1972)
Front Scale: L, LL/1, LL/2, LL/3 [ T/T, SecT/SRT, Cos/S, C ] D, LL3, LL2, LL1
Back Scale: LL/0, K, A, DF [ CF, CIF, CI, C ] D, R1, R2, LL0,
Note: Addition of A scale.
Original Owner: Wisniewski, #3-9842-149 St. (on flap)
Gifted by the Leroy Hausler Collection


Hughes-Owens 341-3120 Versatrig

ISRM 09.01.12.40
Hughes-Owens 341-3120 Versatrig
Made in Japan by Hemmi (same as Post 1450 Versatrig)
Front Scale: L, A [ T T, SecT ST, Cos S, C ] D, DI
Back Scale: K, DF [ CF, CIF, CI, C ] D, R1, R2
Donated by David Hecht, Alexandria, VA


P142 Hughes-Owens 341-3405 w/ Magnifier
Hughes-Owens  341-3405 w/ Magnifier
Made in Japan - Late Era for Canada
Front Scale: 4in // A [ B, CI, C ] D
Back Scale: [ S, L, T ]



S291 Hughes-Owens 341-3526 Student
Hughes-Owens 341-3526 Student
Made in Japan by Hemmi. Same as H-O 1768C
Front Scale: A [ B, CI, C ] D, K
Back Scale: [ S, L, T ]


P209 Hemmi Geotec 341-3425
Hemmi Geotec 341-3425,  dc ID April, 1958
Made in Japan by Hemmi for Canada firm H-O, later Geotec
Front Scale: 5in// A [ B, CI, C ] D, K
Back Scale: [ S, L, T ]


Geotec 341-3690 Versalog II

ISRM 18.07.11.02
Geotec 341-3690 Versalog II (Same scales as Post 1460 Versalog II)
Made in Japan by Hemmi
Front Scale: L, LL/1, LL/2, LL/3 [ T/T, SecT/SRT, Cos/S, C ] D, LL3, LL2, LL1
Back Scale: LL/0, K, A, DF [ CF, CIF, CI, C ] D, R1, R2, LL0,
Note: Addition of A scale.
Gifted by Phil Stanley of Worcster, Massachussettes
Philip Stanley retired from engineering to become a full-time dealer in and appraiser of antique scientific instruments and tools as The Analytical Engine. He has written two books on antique measuring instruments, and numerous articles on instruments and technology, and has given several talks on these subjects. Phil appeared on the Antiques Road Show on PBS, as an appraiser, in 2012, 2013, 2014.


P138 Hughes-Owens B-35
Hemmi Hughes-Owens B-35
Made in Japan by Hemmi for Canada firm H-O
Front Scale: 5in // K, DF [ CF, CI, C ] D, A
Back Adv: Compliments of Hughes-Owens

ODELCO
De Leon Import and Export Corporation, 128 Kalayaan Avenue 3/F, Odelco Building, Quezon City, Philippines
In 1948 Oscar Dee Leon (1917-1994) (photo upper left) founded ODELCO which became the Pacific Rim distributor for Hemmi slide rules. Hemmi designed the Odelco logo and imprinted it on rules shipped to them. Oscar De Leon established the ODELCO housing subdivision around 1965, which is a community in Quezon City, and the school was named for him. In 1952, De Leon Import & Export Corporation started its business in distributing office and school equipment manufactured in the United States, Japan and Germany. The company is still thriving (Modern logo shown) selling geophysical and hydrological equipment. Oscar de Leon, Jr, (photo lower left) became the president of ODELCO in 1977. His son, the grandson of the founder, Oscar Ramoncito De Leon IV, manages the day-to-day operations as VP and COO of the company. Odelco Hemmi slide rule page. Odelco Early Hemmi slide rule page


Odelco (Hemmi 32) Mannheim 10cm w/Magnifier

ISRM 22.09.13.38
Odelco (Hemmi 32) Mannheim 10cm w/Magnifier c1972
Made in Japan for Odelco, Phillipines.
Note: All plastic magnifier, not metal-framed.
Front Scale: 10cm // A [ B, CI, C ] D
Back Scale: [ S, L, T ]
Gift of Joann Lynn of Washington, DC., in memory of her husband Joel J. Lynn (1943-2022)


P081 Hemmi 149A (Odelco)
P081 Hemmi 149A
Made in Japan by Hemmi for Odelco in the Philippines.
Front Scale: L, K, A [ B, TI, SI, C ] D, LL0, LL/0
Back Scale: LL/1, LL/2, LL/3, DF [ CF, CIF, CI, C ] D, LL3, LL2, LL1
Odelco Logo


Hemmi 257-L (Odelco)

REF
Sun Hemmi 257 (Odelco) - For Chemical Engineer
Made in Japan by Sun Hemmi for Odelco in the Philippines.
Front Scale: L, K, A, DF [ CF, CIF, CI, C ] D, LL3, LL2, LL1
Back Scale: Ch(A-M), Ch(N-Z), M1(Xw) [ M2(X), Temp(F,C,K)°, LM ] mmHg, Kg/cm2, inHgVac, tω
Archive - Herman van Herwijnen's SRC


Hemmi 259-D (Odelco) Expert Mechanical Engineer (1973)

ISRM 12.06.24.04
Sun Hemmi 259-D - For Expert Mechanical Engineer
Made in Japan for Odelco - date code XI (Sep 1973)
Front Scale: L, K, A [ B, T, S, ST, C ] D, DI, LL0, LL/0
Back Scale: LL/1, LL/2, LL/3, DF [ CF, CIF, CI, C ] D, LL3, LL2, LL1
Donated by Anonymous collector and daughter.
The collector, who prefers to remain anonymous, obtained a B.S. degree in Physics from Taiwan's National Tsing Hua University in 1971. His love for computation has encouraged him to build a collection of slide rules, HP and TI calculators, as well as abaci, many displayed at ISRM.


Click For more Hemmi
OEM Slide Rules

1926 Hemmi Catalog
4.09MB pdf

Pre-1940 Hemmi Slide Rule
Manufacturing Process

1958 Hemmi Catalog
1.13MB pdf

Many Hemmi and Post slide rules have date codes stamped into the body of the stock.
Two letters [Year][Month].

For those that don't, go to the Hemmi Catalogue Raisonne

and Slide Rule Dates and Timelines pages

Year Codes

A B C D E F G H I J K L M
1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962
N O P Q R S T U V W X Y Z
1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975
Month Codes
A B C D E F G H I J K L
Jan. Feb. Mar. Apr. May June July Aug. Sep. Oct. Nov. Dec.

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International Slide Rule Museum