| National Museum of American History

Hemmi, a Japanese slide rule firm established in 1895, became notable after it began in 1912 to apply celluloid to bamboo, resulting in rules that did not shrink or expand like wooden rules.

Description: Hemmi, a Japanese slide rule firm established in 1895, became notable after it began in 1912 to apply celluloid to bamboo, resulting in rules that did not shrink or expand like wooden rules. Hemmi also made rules for export, and it became the sole supplier of linear slide rules to the Frederick W. Post Company of Chicago by 1932. Post sold model 1446 between 1931 and 1949 for $1.50. The donor reported that he purchased this example in 1936 while studying at Colgate University. This date is consistent with the company logo on the case, which was in use in the 1930s, and with the lack of reference on the instrument to "Occupied Japan," as Hemmi rules were marked from 1946 to 1950. Hemmi products were not available in the United States during World War II.; This one-sided bamboo rule is coated with white celluloid only on the front. There are A and D scales on the base. The D scale is marked at each end: Quot (/) +1; Prod (/) -1. The slide has B and C scales on one side and S, L, and T scales on the other side. The indicator is glass in a metal frame. The rule's backing is clear and silver celluloid. It contains a chart with fractions converted to decimal numbers, powers of П, relationships between scales C and D, and weights of metals.; The center top of the base is marked in red: THE FREDERICK POST CO. NO. 1446. The center bottom of the base is marked in black: "SUN" (between two drawings of the sun); HEMMI; MADE IN JAPAN. The edge of the indicator is also engraved: SUN (between two drawings of the sun) HEMMI.; The rule is stored in a rectangular black Fabrikoid case which is opened by removing the right end. This end is marked in white: POSTS (/) 1446. The back of the case is marked: MADE IN JAPAN. The rule came with a stapled leaflet of instructions, 1982.0386.03.; References: Dieter von Jezierski, Slide Rules: A Journey Through Three Centuries, trans. Rodger Shepherd (Mendham, N.J.: Astragal Press, 2000), 79–82; International Slide Rule Museum, "Slide Rule Dates and Time-Lines," http://sliderulemuseum.com/SR_Dates.htm; Posts Dependable Drawing Materials, 18th ed. (Chicago: The Frederick Post Company, 1936), 174. Price lists for this catalog dated August 1937 and May 1940 show model 1446 on pages 11–12 and 27–28, respectively.
Location: Currently not on view

date made: 1931-1939

maker: SUN HEMMI JAPAN CF
distributor: Frederick Post Co.

ID Number: 1982.0386.02
accession number: 1982.0386
catalog number: 1982.0386.02

This instrument consists of a wooden cylinder covered with paper scales, wooden handles at the ends of the cylinder, and a metal sleeve lined with felt. The sleeve, which is painted maroon, holds the cylinder. A slot 1.5cm wide and a paper scale run the length of the sleeve.

Description: This instrument consists of a wooden cylinder covered with paper scales, wooden handles at the ends of the cylinder, and a metal sleeve lined with felt. The sleeve, which is painted maroon, holds the cylinder. A slot 1.5cm wide and a paper scale run the length of the sleeve. For detailed information, see MA.333636. The only difference between the instruments is that the sleeve on this example has been decoratively painted in gold. Keuffel & Esser of New York sold this model for $5.00 from 1903 to 1923.; The School of Forestry of the University of Montana in Missoula donated this example to the Smithsonian in 1983. The School of Forestry was established at the State University of Montana (later Montana State University, now the University of Montana) in 1913. By 1921, courses taught in the school of forestry included—subject to student demand—a course on the slide rule. The course covered the theory and use of the Mannheim, Stadia, Polyphase, and Log rules.; References: State University of Montana, Annual Catalogue (Missoula, 1921), 125; "The Jack Burton Collection," Journal of the Oughtred Society 2, no. 1 (1993): 15–18; Bob Otnes, "The 31st (1903) and 32nd (1906) Editions of the K&E Catalogue" Journal of the Oughtred Society 11, no. 2 (2002): 24–32; Bob Otnes, "Keuffel & Esser Slide Rules 1909" Journal of the Oughtred Society 12, no. 1 (2003): 25–32.
Location: Currently not on view

date made: 1903-1923

maker: Keuffel & Esser Co.

ID Number: 1983.0472.01
catalog number: 1983.0472.01
accession number: 1983.0472

This ten-inch white plastic one-sided linear slide rule has a clear plastic indicator that goes all the way around the instrument. The posts holding the rule together are also white. The base has K, A, D, and L scales, with B, T, S, CI, and C scales on the slide.

Description: This ten-inch white plastic one-sided linear slide rule has a clear plastic indicator that goes all the way around the instrument. The posts holding the rule together are also white. The base has K, A, D, and L scales, with B, T, S, CI, and C scales on the slide. The left end of the slide is marked: PICKETT (/) NO. 120. The right end of the slide is engraved with the Pickett triangular logo used between 1958 and 1962. The bottom right corner of the base is marked: MADE IN U.S.A.; The rule fits in a black imitation leather stitched sheath. Pickett advertised this "trig trainer" slide rule in the September 17, 1961, issue of the Chicago Daily Tribune. In later years, Pickett added the model name "Microline" to the model number. The company intended that students would learn fundamental operations with these rules and then graduate to its more complex aluminum rules. Compare the five-inch student rule, 1991.0445.02, and the ten-inch Microline duplex rule, 1989.0325.07.; Mechanical engineer Edward L. Heller (1912–2007) donated this example to the Smithsonian. From 1956 to 1959, he worked as a nuclear project engineer for H. K. Ferguson Co. He was a technical manager for General Dynamics Corporation from 1959 to 1967. He married in 1946 and raised two children. Since the slide rule was probably purchased about 1960, Heller may have expected that his children would use it.; References: American Men and Women of Science, 12th ed. (New York: J. Cattell Press, 1972), iii:2620; International Slide Rule Museum, "Pickett All-Metal Slide Rules," http://sliderulemuseum.com/SR_Dates.htm#Pickett.
Location: Currently not on view

date made: 1958-1962

maker: Pickett & Eckel, Incorporated

ID Number: 1984.1068.03
accession number: 1984.1068
catalog number: 1984.1068.03

This inexpensive five-inch white plastic rule has A and D scales on the front of the base; B, CI, and C scales on the front of the slide; and S, L, and T scales on the back of the base. The indicator is clear plastic. Underneath the slide is a table of equivalents and settings.

Description: This inexpensive five-inch white plastic rule has A and D scales on the front of the base; B, CI, and C scales on the front of the slide; and S, L, and T scales on the back of the base. The indicator is clear plastic. Underneath the slide is a table of equivalents and settings. The front of the slide also has a scale of six inches, divided to sixteenths of an inch, and a scale of 15.3 centimeters, divided to millimeters. The back of the slide has a table of decimal equivalents from 1/64 to 63/64. A brown imitation leather sheath is marked: POCKET SLIDE RULE MADE IN U.S.A. No. 27. For instructions, see 1988.0807.06. The postal code on the instructions indicates a date between 1943 and 1963. According to this sheet, the C-Thru Ruler Company of Hartford, Conn., made this rule. This firm, established in 1939 by teacher Jennie Zachs and acquired by Acme United Corporation in 2012, continues to make transparent drafting tools and drawing instruments.; References: Brian Dowling, "Acme United Acquires Bloomfield's C-Thru Ruler," Hartford Courant, June 11, 2012; "About Us," C-Thru Ruler Company, http://www.cthruruler.com/.
Location: Currently not on view

date made: 1943-1963

maker: C-Thru Ruler Company

ID Number: 1988.0807.02
accession number: 1988.0807
catalog number: 1988.0807.02

This aluminum slide rule is coated in "Eye Saver" yellow, as denoted by the model number. It is held together with aluminum braces; the indicator is nylon (also denoted by the model number) with three metal screws.

Description: This aluminum slide rule is coated in "Eye Saver" yellow, as denoted by the model number. It is held together with aluminum braces; the indicator is nylon (also denoted by the model number) with three metal screws. The front of the rule has A, D, and L scales, with B, CI, and C scales on the slide. The scales are about ten inches long. The slide and the top of the rule are both marked: MODEL N901-ES (/) SIMPLEX (/) MATH RULE. The other end of the slide bears the Pickett logo and the mark: MADE IN U.S.A.; The back of the rule has X and D* scales, with Y and C* scales on the slide. The top of the rule is marked: PICKETT, INC.; MODEL N901-ES; SIMPLEX MATH RULE. The bottom of the rule is marked: COPYRIGHT 1965; PICKETT, INC. SANTA BARBARA. CALIF.; MADE IN U.S.A.; The rule fits in a black leather sheath. The sheath was received in a green, white, and black cardboard box. One end of the box is marked: PickETT (/) 901-ES (/) ELEMENTARY MATH. It also is marked: about this rule: (/) 10 scales are keyed to (/) new math. Aids under- (/) standing of addition, (/) subtraction, multiplica- (/) tion, division and Base 10 (/) relationships. Grade 3 up. The inside of the box top flips up for display. The box slides into a green, white, and black cardboard cover. The top and sides of the box cover are each marked: PickETT; ALL METAL (/) SLIDE (/) RULE.; The box also contains a yellow paper slide rule guarantee and registration card. The object's serial number is A1216143. A 48-page instruction manual by Maurice L. Hartung is stored separately (1995.0126.02.01).; The X and Y scales were used for addition and subtraction and were unique to Pickett. Donor Lawrence J. Kamm conjectured that Hartung, a mathematics professor at the University of Chicago, recommended they be added to this product. According to Kamm, Hartung encouraged company cofounder Ross Pickett to market its slide rules only to schoolchildren. In order to provide scientists and engineers with access to rules such as the Decimal Keeper (1995.0126.01), Kamm opened a mail-order business that distributed Pickett's products.; References: Peter M. Hopp, Slide Rules: Their History, Models, and Makers (Mendham, N.J.: The Astragal Press, 1999), 209–210; Maurice L. Hartung, Complete, Semi-Programmed Teaching Instructions for the Use of Elementary Simplex Math Slide Rule (Santa Barbara, Calif.: Pickett, Inc., 1965); accession file; International Slide Rule Museum, "Pickett," http://sliderulemuseum.com/Pickett.htm.
Location: Currently not on view

date made: after 1965
date received: 1995

maker: Pickett & Eckel, Incorporated

ID Number: 1995.0126.02
accession number: 1995.0126
catalog number: 1995.0126.02

This white plastic circular slide rule is on a rectangular base that has a 4-inch ruler on the left side and a 10-cm ruler on the right. A black plastic tape attached along the top edge reads: MATLACK.

Description: This white plastic circular slide rule is on a rectangular base that has a 4-inch ruler on the left side and a 10-cm ruler on the right. A black plastic tape attached along the top edge reads: MATLACK. The top of the base is marked: CONCISE (/) SCIENCE TABLES (/) AND CIRCULAR SLIDE RULE. The slide rule has a D scale along the outer rim. A rotating disc fastened with a metal grommet has C, CI, L, A, S, T, and K scales. There is a clear plastic rotating indicator, which is labeled in red with the letters for the scales. The bottom of the base is marked: BY SAMA & ETANI.; The back of the instrument has a chart for converting temperatures from Celsius to Fahrenheit and a periodic table of the chemical elements. The bottom right corner of the back is marked: © 1968 CONCISE INTERNATIONAL CO. LTD. The left edge is marked: DESIGNED BY SAMA & ETANI, INC., GROTON, MASSACHUSETTS 01450, U.S.A. (/) MADE IN JAPAN BY CONCISE MODEL 600.; A rectangular plastic card fits inside a slot in the base. The card provides various conversion tables for energy, power, the Greek alphabet, velocity, volume, mass, force, length, and area. This side of the card is printed so that the card can be pushed out halfway from either side of the base, and the printed tables will appear right-side-up. The back of the card has tables for gas constant values and pressure, along with lists of mathematical formulas and chemical and physical data. One edge of the card is marked: ©1968 CONCISE INTERNATIONAL CO., LTD. INSERT - ST.; The instrument fits in a rectangular black plastic case. There is no instruction manual, but the instrument likely was originally accompanied by a copy of: Sama & Etani, Reference Tables and Circular Slide Rule (Groton, Mass., 1969), http://sliderulemuseum.com/Manuals/M219_refC36_Concise_SamaEtani_ReferenceTables.pdf.; The donor, Glenn Matlack, purchased this slide rule in the fall of 1968 for his junior high school general science course at Tower Hill School in Wilmington, Del. Sama & Etani designed and distributed several slide rules made by Concise. For other slide rules by Concise and the company history, see 1985.0636.02, 1996.0141.01, and 2003.0012.01.; Reference: Accession file.
Location: Currently not on view

date made: 1968

maker: Concise

ID Number: 2006.0173.01
accession number: 2006.0173
catalog number: 2006.0173.01

In 1881, Edwin Thacher, a "computing engineer" for the Keystone Bridge Company in Pittsburgh, Pennsylvania, received a patent for an improvement in slide rules. Thacher, a graduate of Rennselaer Polytechnic Institute, spent much of his career designing railway bridges.

Description: In 1881, Edwin Thacher, a "computing engineer" for the Keystone Bridge Company in Pittsburgh, Pennsylvania, received a patent for an improvement in slide rules. Thacher, a graduate of Rennselaer Polytechnic Institute, spent much of his career designing railway bridges. To assist in his calculations, he designed a cylindrical slide rule. Thacher's rule, though it fit on a desk, was equivalent to a conventional slide rule over 59 feet long. The rule had scales for multiplication and division and another scale, with divisions twice as large, for use in finding squares and square roots. There were no trigonometric scales.; To produce his "calculating instrument," Thacher turned to the London firm of W. F. Stanley. The company even designed a special dividing engine for preparing the scales for the instrument. These were printed on paper sheets, which were pasted to the drum and the slats. In this example, the paper is also printed in italics on the right side: Patented by Edwin Thatcher [sic], C.E. Nov. 1st 1881. Divided by W. F. Stanley, London, 1882. Made by Keuffel & Esser Co. N.Y. Wayne Feely has suggested that K&E began manufacturing (as opposed to simply distributing) Thacher cylindrical slide rules in 1887, indicating 1887 is the earliest date for this example of the instrument.; The drum is rotated with wooden handles. The cylinder of slats is held in place with a brass frame, which is affixed to a wooden base. A paper of DIRECTIONS AND RULES FOR OPERATING is glued to the front of the base. A small silver metal tag affixed to the front right of the base is engraved: KEUFFEL & ESSER CO. (/) NEW-YORK (/) 589. A metal extension on the front, screwed to both sides of the frame, bears a fixed holder and thumbscrew that once held a magnifying glass.; A paper K&E label on the inside lid of the instrument's mahogany case is marked in ink: 1741/589 (/) Thacher's (/) Calculating (/) Instr. The inside of the lid and the bottom of the base are both painted: M59. The back of the base is missing a chip 5 cm in length. The left and right sides of the case both bear labels marked in ink: INSTRUMENT (/) CALCULATING (/) THATCHER. A diagonal line is drawn through the second T in "Thatcher" on the right side.; Keuffel & Esser Company of New York sold versions of the Thacher cylindrical slide rule from at least 1883 until about 1950. There were two models, one with a magnifying glass (K&E model 1741, K&E model 4013 after 1900), and one without (K&E model 1740, later K&E 4012). This is a model 1741. In 1892, the model 1741 sold for $40.00. The Physics Department of the United States Military Academy transferred this example to the Smithsonian in 1958.; References: Edwin Thacher, "Slide-Rule" (U.S. Patent 249,117 issued November 1, 1881); Wayne E. Feely, "Thacher Cylindrical Slide Rules," The Chronicle of the Early American Industries Association 50 (1997): 125–127; Peggy Aldrich Kidwell, Amy Ackerberg-Hastings, and David Lindsay Roberts, Tools of American Mathematics Teaching, 1800–2000 (Baltimore: The Johns Hopkins University Press, 2008), 113–114; Wilfred Scott Downs, ed., "Nickel, Frank F.," Who's Who in Engineering, (New York, 1931), iii:957; Catalogue of Keuffel & Esser (New York, 1892), 131. This was the first K&E catalog to list the model 1741.
Location: Currently not on view

date made: 1890s

maker: Stanley, William Ford; Keuffel & Esser Co.

ID Number: MA.315663
accession number: 217544
catalog number: 315663

This instrument consists of a wooden cylinder covered with paper scales, wooden handles at the ends of the cylinder, and a metal sleeve lined with felt. The sleeve, which is painted maroon, holds the cylinder.

Description: This instrument consists of a wooden cylinder covered with paper scales, wooden handles at the ends of the cylinder, and a metal sleeve lined with felt. The sleeve, which is painted maroon, holds the cylinder. Running the length of the sleeve are a slot 1.5 cm wide and a paper scale.; The instrument is marked on the paper covering the cylinder: “WEBB’S STADIA SLIDE RULE”, (/) DESIGNED BY WALTER LORING WEBB, C. E. (/) MANUFACTURED BY KEUFFEL & ESSER CO., N.Y. It also is marked there: DIRECTIONS. SLIDE THE CYLINDER UNTIL ONE END OF THE CYLINDER IS SET AT THE DISTANCE MARK ON THE SCALE AND SO THAT THE GIVEN ANGLE OF ELEVATION ALSO COMES TO SOME PART OF THE SCALE. THE REQUIRED QUANTITY IS 1/10 (1/100 or 1/1000, AS SHOWN BY THE MARK ON CYLINDER) OF THE SCALE READING AT THAT ANGLE MARK.; The stadia slide rule was used in topographical surveying to determine the elevation and geographical position of points and objects. Initially, a chain and compass or transit had been used to determine geographical position, with a level employed to obtain relative elevations. Greater efficiency in these measurements was then found by using a plane-table.; In about 1864, the U.S. Lake Survey adopted a third system, first used in Italy about 1820. A stadia rod was placed at the point of interest and sighted through the telescope of a transit. The distance to this point was found by observing the portion of the graduated rod shown between certain cross-hairs of the telescope. To find the elevation of the point, one examined the vertical angle on the vertical circle of the transit when the telescope was aimed at a point on the stadia rod that was the same height off the ground as the telescope. A stadia slide rule was then used for data reduction.; Keuffel & Esser of New York introduced a 20-inch linear stadia slide rule in 1895. It sold under various model numbers (1749, 4101, N-4101) until 1952. In 1897, the firm introduced a 50-inch linear stadia slide rule designed by Branch H. Colby of St. Louis. Colby's stadia slide rule (model number 1749-3, later 4125) sold until 1903. Textbook authors such as John Butler Johnson endorsed the rule, but it was awkward to carry in the field.; Walter Loring Webb (1863–1941), a civil engineer who graduated from Cornell University and taught there and at the University of Pennsylvania, proposed a rule that had parallel scales arranged on a cylinder, reducing the length of the instrument to about 16 inches. K&E sold Webb's stadia slide rule for $5.00 from 1903 to 1923.; One end of the sleeve is painted: 1803. This may be an inventory number from the University of Missouri's Department of Civil Engineering, which donated the instrument in 1972. The university began teaching civil engineering in 1859, and its School of Engineering was renamed the College of Engineering in 1877.; See also 1983.0472.01. For circular stadia slide rules, see MA.336425, 1987.0221.01, and 2002.0282.01.; References: John Butler Johnson, The Theory and Practice of Surveying, 16th ed. (New York: John Wiley & Sons, 1908), 237ff; Walter Loring Webb, Railroad Construction: Theory and Practice, 7th ed. (New York: John Wiley & Sons, 1922), 22–23; Wayne E. Feely, "K & E Slide Rules," The Chronicle of the Early American Industries Association 49, no. 5 (1996): 50–52; Catalogue and Price List of Keuffel & Esser Co., 31st ed. (New York, 1903), 308; Mark C. Meade, "A History of the College of Engineering at the University of Missouri – Columbia," Archives of the University of Missouri, http://muarchives.missouri.edu/c-rg9-eng.html.
Location: Currently not on view

date made: 1903-1923

maker: Keuffel & Esser Co.

ID Number: MA.333636
accession number: 300659
catalog number: 333636

Aeronautical engineer George Norman Albree (1888–1986) designed airplane components and slide rules. This is an example of his Duplex slide rule, which he intended to be used by grade school children.

Description: Aeronautical engineer George Norman Albree (1888–1986) designed airplane components and slide rules. This is an example of his Duplex slide rule, which he intended to be used by grade school children. It is printed on both sides of a cardboard circle and consists of a logarithmic spiral scale for numbers from 10,000 to 32,100 on the front or "A" side and numbers from 31,170 to 100,000 on the back or "B" side. A rotating clear plastic indicator wraps around both sides.; On both sides, the center of the spiral is marked: ALBREE TRULOG DUPLEX (/) MODEL 18. Inside the fifth ring of the spiral on the front, the instrument is marked: ©1945 (/) G. NORMAN ALBREE (/) BOSTON MASS. The instrument arrived with a plain square paper case, an instruction manual, and a green paper bag. The cover of the manual reads: MANUAL (/) of the (/) TRULOG DUPLEX (/) Precision Pocket Calculator (/) Multiply - Divide - Raise to Any Power - Extract Any Root. The booklet was copyrighted in 1948. The bag is marked: THE (/) TRULOG DUPLEX (/) With Right Hand Instruction System.; Albree renewed the copyrights for the Albree Trulog Duplex (R560370) and Albree Trulog Spiral (R560371) in 1973. See also MA.335486 and MA.335487.; References: Timothy Hughes, "The George Norman Albree Papers," New England Ancestors 5, no. 3 (2004): 46, http://www.americanancestors.org/PageDetail.aspx?recordId=134553447; Library of Congress, Catalog of Copyright Entries, Part 4, n.s. 40 (1945 index): 287; Catalog of Copyright Entries: Books: Part 1A, 3rd ser. 2, no. 1 (1948): 313; Library of Congress Copyright Office, Renewal Registrations: Works of Art (July-December 1973): 476; Henry W. Syer and Donovan A. Johnson, "Aids to Teaching," Mathematics Teacher 43, no. 5 (1950): 215–221, on 220; accession file.
Location: Currently not on view

date made: after 1948

maker: Albree, G. Norman

ID Number: MA.335484
catalog number: 335484
accession number: 321674

The slide rule is a device to assist in multiplication, division and other mathematical operations. Invented in the 1600s, it became popular in American science and engineering in the 1890s.

Description: The slide rule is a device to assist in multiplication, division and other mathematical operations. Invented in the 1600s, it became popular in American science and engineering in the 1890s. By the 1930s, slide rule use was taught in high schools.; From 1962 until 1972, Harvard University faculty cooperated with others in developing a humanistically oriented high school physics course that might attract more students to the subject. Staff developed not only textbooks, handbooks, transparencies and film loops but this extremely simple and inexpensive plastic slide rule.; The instrument has two circular logarithmic scales for multiplication and division (most elementary slide rules also had scales for taking squares and square roots). There also are linear scales of inches and centimeters.; A stylized bubble chamber image, the logo of Project Physics, appears over the rule. The slide rule was designed so that "Harvard Project Physics" showed just over the shirt pocket of a boy carrying it. This design may reflect the fact that there were no female undergraduates at Harvard College at the time. Not long after this slide rule was made, inexpensive pocket calculators displaced the slide rule.
Location: Currently not on view

date made: ca 1965

ID Number: 1988.0539.01
accession number: 1988.0539
catalog number: 1988.0539.01

In the early twentieth century, a growing proportion of American children attended public schools. However, some continued to prefer private academies.

Description: In the early twentieth century, a growing proportion of American children attended public schools. However, some continued to prefer private academies. For example, the Thurston Prep School, founded in Shadyside, Pennsylvania, in 1887, was devoted to teacher training for young women. A similar school in Shadyside – which also had young boys as students – was established in 1902 and soon named the Winchester School. Financial difficulties at the time of the Depression led to a merger of the two schools in 1935 – male students were then limited to kindergarten and first grade, and the curriculum resembled public elementary schools and high schools. Winchester Thurston moved to new premises in 1967, and at about that time purchased this teaching slide rule. The instrument was donated to the Smithsonian by the school through the good offices of Frances Glockler Hein (1923-2012). Mrs. Hein, as she was known to students, was born in California, raised in Minneapolis, and attended the University of Iowa. In late 1943 she graduated from iowa with a B.A. in mathematics. The next year she married a slightly older University of Iowa student, Richard E. Hein, who then was studying chemistry at Iowa State University and working on the Manhattan Project. They soon had four sons. By 1964, the boys were sufficiently grown for her to take a position at Winchester Thurston, where she taught mathematics for over twenty years.; In 1967, Winchester Thurston moved to a new campus. At about that time, the school acquired this 79-inch demonstration slide rule. It is made of painted wood, with a plastic cursor that has a wooden frame. In the early seventeenth century, the Scottish mathematician John Napier had discovered functions known as logarithms which make it possible to reduce problems of multiplication, division, and taking the roots of numbers to additions and subtractions. On a slide rule, the logarithms of numbers are represented as lengths. To multiply, one length is set on the base, and another added to it using the slide. The sum of the logarithms, which gives the product, is read off using the cursor. This slide rule also has scales for finding the squares, cubes, square roots, and cube roots of numbers.; Slide rules had first became popular in the United States in the 1890s, especially among engineers and scientists. Use of the device was taught in high schools and universities using oversized instruments like this. During the 1960s, the United States placed new emphasis on teaching mathematics and science. By the late 1970s, slide rules would be almost entirely displaced by handheld electronic calculators.; References:; Yearbooks and student newspapers of the University of Iowa.; Registrar's Office, University of Iowa.; Online obituary of Frances G. Hein at tributes.com.; Winchester Thurston School, Thistle Talk Commemorative Edition, vol. 39 #1, Summer, 2010.
Location: Currently not on view

Date made: 1967

fabricator: Keuffel & Esser Co.

ID Number: 1987.0137.01
accession number: 1987.0137
catalog number: 1987.0137.01

Aluminum	Chromium	Metal	Sterling Silver
Bamboo	Ivory	Paper	Wood
Boxwood	Magnesium	Plastic	Yew
Brass	Mahogany

Index by Material

Hemmi Simplex Slide Rule Retailed by Post (1446)

Keuffel & Esser 4105 Webb's Stadia Cylindrical Slide Rule

Pickett 120-T Student Simplex Slide Rule

C-Thru Pocket Slide Rule

Pickett N901-ES Simplex Slide Rule

Concise 600 Science Tables and Circular Slide Rule

Keuffel & Esser 1741 Thacher Cylindrical Slide Rule

Keuffel & Esser 4105 Webb's Stadia Cylindrical Slide Rule

Albree Trulog Duplex Circular Logarithm Table

Harvard Project Physics Circular Slide Rule

Keuffel & Esser 68-1944 Demonstration Slide Rule