Linear Slide Rules

Between 1614 and 1622, John Napier discovered logarithms, Edmund Gunter devised a scale on which numerals could be multiplied and divided by measuring the distance between two logarithmic numbers with a pair of dividers, and William Oughtred put two such scales alongside each other, moving one on a slide so that the distance between the numbers could be read off directly. The speed with which these developments unfolded suggests the power that logarithms provided for reducing the tedium of calculation. By the 1680s, the English used slide rules in carpentry and in gauging (estimating liquid volumes)—the instruments were quite helpful for determining excise taxes on barrels of liquor.

It was not until the late eighteenth century that slide rules were commonly utilized in the manufacture of machines and machine tools, most notably by James Boulton and James Watt. Several more decades passed before slide rule use became widespread throughout Europe. French artillery officer Amedée Mannheim fostered acceptance of the rectangular or linear form of the instrument in 1851 by standardizing the general types of scales and the order in which the scales were arranged. Mannheim also developed the cursor or indicator, which made it easier to read results from two scales that were not adjacent to each other. By the 1870s, German companies made slide rules one of the first consumer products to be fashioned out of plastic (specifically, sheets of celluloid laminated to a wooden frame), and they built dividing engines that permitted mass production of the scales engraved on slide rules. In the United States in the 1890s, Keuffel & Esser of New York City pioneered first the import and then the domestic manufacture of linear slide rules. Numerous other companies entered the market in the 20th century.

Image of an advertisement for an Engineers Slide Rule
Keuffel & Esser was one of the first American firms to import linear slide rules from Europe. Catalogue and Price List of Keuffel and Esser, 13th ed. (New York, 1880), 71. NMAH Trade Literature Collection, Smithsonian Institution Libraries. AHB2013q009220

A quick tour of what you can expect to see on a slide rule starts with the C and D scales, which both represent the standard number line. To multiply two numbers, set the 1 on the C scale above the first number to be multiplied on the D scale. Look at the second number to be multiplied on the C scale; the number below it on the D scale is the answer. For example, to multiply 2 by 3, set 1 on C over 2 on D, and then look below 3 on C to see the answer 6 on D. Division is accomplished by reversing the process. To calculate 6 ÷ 3, set 3 on C over 6 on D, then look at 1 on C to see the answer 2 on D. To deal with numbers larger than 10 or smaller than 1, the user must mentally move the decimal point. Slide rule users also had to be able to estimate distances between marks on the scales, since there was no way to include all of the digits needed to solve a problem such as 3.14 X 2.7. (On linear and circular slide rules, the answer is "approximately 8.48." Web sites on the Resources page provide more detailed training in using slide rules.)

Instructions for multiplying two numbers on a slide rule frpm the Eugene Dietzgen Co.,
Instructions for multiplying two numbers on a slide rule. Eugene Dietzgen Co., Self-teaching Instruction Manual [for] Maniphase Slide Rule (Chicago, [1950s]), 4. NMAH Mathematics Collection, cat. no. 1988.0367.02. AHB2013q009216

The basic process for setting up and solving problems is the same for operations on other scales. If the numbers used in the calculation produce a result off the ends of the scales, a user employs the CI and DI scales, which put the number line in inverse, or reverse, order. If the numbers still extend past the end of the instrument, the user may try the "folded" CF and DF scales, which start numbering at π instead of at 1. The A and B scales are number lines of squares, so they are used with the C or D scales to square (or take the square root of) a number. The K scale provides cubes and cube roots. L scales represent common logarithms, S scales give sines and cosines, and T scales indicate tangents.

This eight-inch wooden Mannheim linear slide rule is coated with white celluloid and has a brass indicator in the single chisel style. It has no endpieces. The top edge is beveled and has a scale of 20 centimeters, divided to millimeters.
Description
This eight-inch wooden Mannheim linear slide rule is coated with white celluloid and has a brass indicator in the single chisel style. It has no endpieces. The top edge is beveled and has a scale of 20 centimeters, divided to millimeters. A 20-centimeter scale, divided to millimeters, is on the front edge. A third 20-centimeter scale under the slide is numbered from 22 to 41.
The top of the base has a scale divided logarithmically from 1 to 10 twice. The bottom of the base has a scale divided logarithmically from 1 to 10. These are the usual A and D scales, although they are not lettered. One side of the slide has the same two scales (the usual B and C scales, although they are not lettered). The other side of the slide has a scale of tangents that runs from 0 to 45 degrees and is lettered T; a scale of equal parts that runs from 0 to 10 and divides every two centimeters into 50 increments; and a scale of sines that runs from 70 to 0 and is lettered S. Compare to MA.318474. There is a place on the back of the instrument for a table of physical constants, but there is no table.
The top of the base is marked: TAVERNIER-GRAVET. The bottom of the base is marked: RUE MAYET 19.PARIS. It is also marked there: KEUFFEL & ESSER Co NEW-YORK & CHICAGO. The back is marked: MÉDAILLES D'OR 1878 ET 1889.
The British engineer's rule was brought to France by Edme-François Jomard in 1815, and by around 1820 Paul-Etienne Lenoir was manufacturing them in Paris. Lenoir's firm was succeeded by Gravet-Lenoir and later Tavernier-Gravet. From about 1851, Tavernier-Gravet manufactured a slide rule on the design of Amédéé Mannheim; this is such a slide rule. It was made after Tavernier-Gravet was awarded gold medals at world's fairs held in Paris in 1878 and 1889.
Before Keuffel & Esser manufactured its own rules around the turn of the 20th century, the company sold slide rules from Tavernier-Gravet and from Dennert & Pape of Germany. (Additional company history is provided with MA.318477, MA.318478, and MA.326613.) Although the scales and indicator resemble the ten-inch model 479–2 (subsequently numbered 1746N and 1746), a rule of this length (scales about 8" long) is not listed in K&E catalogs. The ten-inch version with brass indicator cost $4.50 between 1883 and 1890. In 1892 the single-chisel indicator was replaced with a double-chisel indicator.
References: Florian Cajori, A History of the Logarithmic Slide Rule and Allied Instruments (New York: Engineering News Publishing Company, 1909), 55–58, 80–81; M. Jomard, "The Slide Rule in France—1815," trans. Francis Wells, Journal of the Oughtred Society 8, no. 2 (1999): 11–16; Catalogue of Keuffel & Esser, 17th ed. (New York, 1883), 93; Catalogue of Keuffel & Esser, 20th ed. (New York, 1887), 129; Catalogue of Keuffel & Esser, (New York, 1890), 131.
Location
Currently not on view
date made
1889-1892
maker
Tavernier-Gravet
ID Number
MA.318473
accession number
235479
catalog number
318473
This 20-inch duplex mahogany slide rule is completely coated with white celluloid and held together with the L-shaped metal end pieces Keuffel & Esser adopted in 1913. The indicator is of the frameless glass type K&E first used in 1915.
Description
This 20-inch duplex mahogany slide rule is completely coated with white celluloid and held together with the L-shaped metal end pieces Keuffel & Esser adopted in 1913. The indicator is of the frameless glass type K&E first used in 1915. The edges are metal, not plastic, and one edge is marked: PAT. APPL'D FOR. On one side, the base has A and D scales, with B, S, and C scales on the slide. The left end of the slide is marked with the model number: < 4087 T >. The left edge of each piece of the rule is stamped with the number 18. The bottom of the base is marked: KEUFFEL & ESSER CO. N.Y.; PAT. JUNE 5, '00 DEC. 22, '08. For information on these patents, see MA.322761 and MA.318475.
On the other side, the base has A, D, and L scales, with BI, T, and CI scales on the slide. The trigonometric scales are divided into degress and minutes. The rule fits into a cardboard box covered with black leather and marked: KEUFFEL & ESSER Co. (/) DUPLEX (/) REG. U.S. PAT. OFF. (/) SLIDE RULE. Introduced in 1909, the 4087 T was discontinued after 1915. K&E only used this combination of scales on this model from 1913 to 1915. It sold for $18.00. The Interstate Commerce Commission transferred this example to the Smithsonian in 1962.
References: Willie L. E. Keuffel, "Slide-Rule" (U.S. Patent 651,142 issued June 5, 1900), "Slide-Rule" (U.S. Patent 907,373 issued December 22, 1908), and "Slide-Rule Runner" (U.S. Patent 1,150,771 issued August 17, 1915); Catalogue of Keuffel & Esser Co., 33th ed. (New York, 1909), 312; Catalogue of Keuffel & Esser Co., 34th ed. (New York, 1913), 303; Catalogue of Keuffel & Esser Co., 35th ed. (New York, 1915), 303.
Location
Currently not on view
date made
1913-1915
maker
Keuffel & Esser Co.
ID Number
MA.321782
catalog number
321782
accession number
246883
This wooden instrument is faced on both sides with white celluloid that is attached with brass screws instead of glue.
Description
This wooden instrument is faced on both sides with white celluloid that is attached with brass screws instead of glue. On one side are 20-inch scales: cosine and sine scales on the upper part of the base, two identical logarithmic scales (in three cycles) labeled TIME SCALE on the slide, and a tangent scale on the lower part of the base. The slide is in two pieces, so the second Time Scale may be removed and adjusted relative to the first Time Scale with the aid of a brass thumbscrew.
Three glass indicators are in three-sided brass frames, two on the upper part of the base and one on the lower part of the base. The top of the base is marked: J. HICKS (/) LONDON. It is also marked: PILOT BALLOON SLIDE RULE MO (O is superimposed on M) 505. MO is an abbreviation for Meteorological Office, and 505 may be a serial number. An inventory sticker on the back reads: DEPARTMENT OF AGRICULTURE (/) US. The inventory number has been cut away. The instrument fits in a wooden case covered with black leather and lined on one side with purple satin.
In the 20th century, the Meteorological Office of Great Britain used pilot balloon slide rules to convert azimuth and elevation readings (taken with theodolites during the ascent of a pilot balloon) into data on wind velocity and direction. James Joseph Hicks (1825–1916), who began supplying instruments to the Office in 1869, made the first pilot balloon slide rule in 1915 from a design by Francis John Welsh Whipple, the Superintendent of Instruments.
After Hicks died, W. F. Stanley & Co. took over manufacture of this rule, called the Mark I, but retained the Hicks name. Additional labels were placed on the scales, such as "Azimuth." By 1927, A. G. Thornton Ltd. and other firms were making the Mark II, which had one slide and four indicators. Production of the Mark I may have continued until 1938.
The U.S. Weather Bureau was a part of the U.S. Department of Agriculture until 1940, when it was transferred to the U.S. Department of Commerce. This instrument apparently was not adopted by American meteorologists, since the Bureau used the Keuffel & Esser polyphase duplex slide rule to convert observations. For examples of that type of slide rule, see MA.318476, MA.321778, and 1981.0933.03. For an American theodolite used to observe pilot balloons, see PH.308184.
References: Martin Brenner, "Pilot Balloon Slide Rules," http://www.csulb.edu/~mbrenner/slide.htm; Malcolm Walker, History of the Meteorological Office (Cambridge: Cambridge University Press, 2012), 220; W. R. Gregg et al., Instructions for Aerological Observers, U.S. Department of Agriculture, Weather Bureau (Washington, D.C.: Government Printing Office, 1921), 78; Deborah J. Warner, "Altitude and Azimuth Instrument," National Museum of American History Physical Sciences Collection: Surveying and Geodesy , http://americanhistory.si.edu/collections/surveying/object.cfm?recordnumber=747475.
Location
Currently not on view
date made
1915-1927
inventor
Hicks, J. J.
maker
Stanley, William Ford
ID Number
MA.315905
catalog number
315905
accession number
222974
This ten-inch mahogany duplex slide rule is coated all around with white celluloid and held together with L-shaped metal end pieces. The front of the base has LL0, A, T, S2, and S1 scales, with B, K, and CI scales on the slide.
Description
This ten-inch mahogany duplex slide rule is coated all around with white celluloid and held together with L-shaped metal end pieces. The front of the base has LL0, A, T, S2, and S1 scales, with B, K, and CI scales on the slide. The LL0 scale is a log log scale of decimal quantities. The A and B scales are identical, divided logarithmically from 1 to 10 twice in the length of the scale in the usual manner. The K scale is also divided logarithmically, but three times in the length of the scale, for use in finding cubes and cube roots. The CI scale is divided logarithmically from 1 to 10 the length of the scale, going in the opposite direction from the A and K scales. The T scale is a scale of tangents and cotangents, doubly numbered with angles given in degrees and minutes. The S1 and S2 scales are scales of sines and cosines, doubly numbered. The top of the base is marked in red: KEUFFEL & ESSER CO.N.Y.; PAT. APRIL 1.'24 OTHER PAT. PENDING; MADE IN U.S.A. The left end of the slide and the front of the rule are marked with a serial number: 448333.
The back of the base has L, LL1, DF, D, LL3, and LL2 scales, with CF, CIF, and C scales on the slide. The right end of the slide is marked in red: < 4090-3 >. A glass indicator has white plastic edges held together with metal screws. One edge is marked: KEUFFEL & ESSER CO.N.Y. The other is marked: PATENTED AUG.17.15. (/) OTHER PAT. PENDING.
Keuffel & Esser advertised model 4090-3 from 1933 to 1936. However, the combination of scales on this example was only issued in 1933, when the rule sold for $10.00. The serial number is consistent with this date. In 1937, model 4090-3 was replaced by model 4080-3.
References: Adolf W. Keuffel, "Log Log Duplex Slide Rule" (U.S. Patent 1,488,686 issued April 1, 1924); K&E Slide Rules and Calculating Instruments (New York, 1933), 10–11; Catalogue of Keuffel & Esser Co., 38th ed. (New York, 1936), 316–317; Dieter von Jezierski, Slide Rules: A Journey Through Three Centuries, trans. Rodger Shepherd (Mendham, N.J.: Astragal Press, 2000), 71–75; Clark McCoy, ed., "Collection of Pages from K&E Catalogs for the 4090-3 & 4091-3 Family of Slide Rules," http://www.mccoys-kecatalogs.com/KEModels/ke4091-3family.htm.
Location
Currently not on view
date made
1933
maker
Keuffel & Esser Co.
ID Number
MA.318479
accession number
235479
catalog number
318479
This five-inch solid Xylonite (celluloid) slide rule is one of several "Ever-There" pocket slide rules made by Keuffel & Esser. This line was noted for its light weight and small size.
Description
This five-inch solid Xylonite (celluloid) slide rule is one of several "Ever-There" pocket slide rules made by Keuffel & Esser. This line was noted for its light weight and small size. There are A, D, and K scales on the base, with B, CI, and C scales on one side of the slide and S, L, and T scales on the other side of the slide. The glass indicator has a metal frame, plastic edges, and metal screws. The top of the base is marked: KEUFFEL & ESSER CO. N.Y.; PAT. 1,875,927; MADE IN U.S.A. The right end of the slide is marked: < 4097C >.
The back of the slide rule has a scale of 5 inches divided to sixteenths of an inch and a scale of 13 centimeters divided to millimeters. The left ends of the back of the rule and of the back of the slide are marked with a serial number: 38642. The rule fits in a leather sheath marked: K&ECO.
After Adolf Keuffel applied for a patent on what became the Ever-There product line on October 29, 1930, K&E introduced this version of slide rule as model 4098 in 1931. It was renamed model 4097C in 1936 and was discontinued around 1951. With a case, it cost $4.15 in 1936 and $5.75 in 1949. By 1959, it was replaced by model 4153-1. Compare to 1981.0933.05 and 1981.0922.08. An instruction booklet, received separately, is 1981.0933.09.
This example was given to the museum by Myron R. Smith (1911–2007), an electronics engineer who used it in a long career at Collins Radio in Cedar Rapids, Ia., then at Honeywell in Minneapolis, and then at Honeywell in Seattle. Smith used the rule to solve problems relating to the testing of broadcast equipment, the design of electronic temperature controls, the design of power transformers, and corporate management.
References: Adolf W. Keuffel, "Slide Rule" (U.S. Patent 1,875,927 issued September 6, 1932); Bob Otnes, "Adolf Keuffel and the Later K&E Slide Rules," Journal of the Oughtred Society 8, no. 1 (1999): 37–38; K&E Slide Rules and Calculating Instruments (New York, 1931), 17; Catalogue of Keuffel & Esser Co., 38th ed. (New York, 1936), 324; K&E Price List Applying to the 41st Edition Catalog (New York, 1949), 32; K&E Price List Applying to the 41st Edition Catalog (New York, 1951), 35; K&E Price List Applying to the 42nd Edition Catalog (New York, 1959), 73; accession file.
Location
Currently not on view
date made
1936-1949
maker
Keuffel & Esser Co.
ID Number
1989.0325.06
accession number
1989.0325
catalog number
1989.0325.06
This ten-inch double-sided mahogany rule is fully covered with white celluloid. On one side, there are L, LL1, DF, D, LL3, and LL2 scales on the base and CF, CIF, CI, and C scales on the slide. The top of the base is marked in red: KEUFFEL & ESSER CO. N.Y.; PATS.
Description
This ten-inch double-sided mahogany rule is fully covered with white celluloid. On one side, there are L, LL1, DF, D, LL3, and LL2 scales on the base and CF, CIF, CI, and C scales on the slide. The top of the base is marked in red: KEUFFEL & ESSER CO. N.Y.; PATS. RE.20,984 1,930,852 2,168,056 2,170,144 PAT. PEND.; MADE IN U.S.A. The right end of the slide is marked with the model number: < 4080-3 >. On the other side, there are LL0, LL00, A, D, DI, and K scales on the base and B, T, ST, and S scales on the slide. The left end of the slide and the front left corner of the base are marked with a serial number: 728903. The indicator is glass with plastic edges held together with metal screws. A piece is missing from the top edge; if it were whole, it would read: KEUFFEL & ESSER CO. N.Y. The bottom edge is marked: PATENT 2,086,502.
In images of the object, the slide is upside down.
The rule fits into a sewn orange leather case. The flap is marked: K & E (/) LOG LOG DUPLEX (/) TRADE TRIG MARK (/) 4080-3S. The S refers to the sewed leather case. A paper table of equivalences was once attached to the case, but most of it has been torn away. The remaining portions resemble the charts on K&E simplex slide rules, such as 1984.1068.01. The back of the case has a metal ring, presumably to fit around a belt loop, and is marked: R. L. HUFFMAN.
K&E used this combination of scales on this model from 1939 to 1947. The serial number on this example is consistent with a date earlier in this time frame. In 1947, it sold for $18.00. Included in the acquisition is a manual by William E. Breckenridge, The Log Log Duplex Slide Rule (1939). Compare this rule to 2007.0181.01.
Robert L. Huffman owned this instrument. It seems likely that he used it as a college student. He received a Bachelor of Mechanical Engineering degree from the University of Minnesota in 1941. Huffman went on to work for Automatic Electric Company of Chicago and then, from 1945, for General Telephone Laboratories.
References: Alfred W. Keuffel, "Slide Rule" (U.S. Patent RE20,984 reissued Janaury 24, 1939); Alfred W. Keuffel, "Slide Rule" (U.S. Patent 1,930,852 issued October 17, 1933); Adolf W. Keuffel, "Runner for Slide Rules" (U.S. Patent 2,086,502 issued July 6, 1937); Carl M. Bernegau, "Slide Rule" (U.S. Patent 2,168,056 issued August 1, 1939); Lyman M. Kells, Willis F. Kern, and James R. Bland, "Slide Rule" (U.S. Patent 2,170,144 issued August 22, 1939); Clark McCoy, "Collection of Pages from K&E Catalogs for the 4081-3 Family of Slide Rules: 4080-3 & 4081-3 Family Groups," http://www.mccoys-kecatalogs.com/KEModels/ke4081-3family.htm; The Automatic Electric Technical Journal 1, no. 2 (July 1948): front matter.
Location
Currently not on view
date made
1939-1947
maker
Keuffel & Esser Co.
ID Number
1992.0437.01
catalog number
1992.0437.01
accession number
1992.0437
This ten-inch two-sided slide rule is made from wood coated with white celluloid and held together with metal end pieces. There are L, LL1, DF, D, LL3, and LL2 scales on one side of the base, with CF, CIF, CI, and C scales on the slide.
Description
This ten-inch two-sided slide rule is made from wood coated with white celluloid and held together with metal end pieces. There are L, LL1, DF, D, LL3, and LL2 scales on one side of the base, with CF, CIF, CI, and C scales on the slide. The top of the base is marked in red: KEUFFEL & ESSER CO. N.Y.; PATS. RE.20,984 1,930,852 2,168,056 2,170,144 PAT. PEND.; MADE IN U.S.A. The right end of the slide is marked with the model number: < 4081-3 >. On the other side, there are LL0, LL00, A, D, DI, and K scales on the base and B, T, ST, and S scales on the slide. The left end of the slide and the front left corner of the base are marked with a serial number: 207806. A glass indicator with plastic edges is held together with metal screws. The top edge of the indicator is marked: PATENT 2,086,502. The bottom edge of the indicator is marked: KEUFFEL & ESSER CO. N.Y.
The instrument fits in a cardboard case covered with black leather. Also in the case is a metal straight edge. The case is marked on the top of the flap: LOG LOG DUPLEX (/) TRADE TRIG MARK. The front of the flap is marked: 4080-3 (/) K + E. Stenciled on the case is: T. M. ROBB. Written on the inside of the flap is: THOMAS ROBB (/) SPAIN, AIR CREW.
This combination of scales was used from 1939 to 1947. The serial number on this example is consistent with a date later in this time frame. In 1947, this model sold with the leather case for $19.75. For later examples of model 4081-3, see MA.318482 and MA.334387. On the patents listed on this instrument, see 1992.0437.01 and 1999.0254.01.
Reference: "K + E Slide Rules and Calculating Instruments Price List," July 1, 1947, http://www.mccoys-kecatalogs.com/KECatalogs/1947/1947kecatprice01.htm.; Dieter von Jezierski, Slide Rules: A Journey Through Three Centuries, trans. Rodger Shepherd (Mendham, N.J.: Astragal Press, 2000), 71–75.
Location
Currently not on view
date made
1939-1947
maker
Keuffel & Esser Co.
ID Number
1990.0687.01
accession number
1990.0687
catalog number
1990.0687.01
This ten-inch mahogany duplex slide rule is coated with white celluloid. There are LL02, LL03, DF, D, LL3, and LL2 scales on one side of the base, with CF, CIF, CI, and C scales on the slide. The right side of the slide is marked in red: © (/) K + E.
Description
This ten-inch mahogany duplex slide rule is coated with white celluloid. There are LL02, LL03, DF, D, LL3, and LL2 scales on one side of the base, with CF, CIF, CI, and C scales on the slide. The right side of the slide is marked in red: © (/) K + E. On the other side of the base, there are LL01, L, K, A, D, DI, and LL1 scales, with B, T, ST, and S scales on the slide. The left end of the slide is marked: 410923. The left end of the top and the bottom of the base are both marked: 923. The indicator is glass, with white plastic edges held together with metal screws. Keuffel & Esser used this arrangement of scales from 1954 to 1962.
The top edge of the rule is marked: PATS. PEND. MADE IN U.S.A. 4080-3 LOG LOG DUPLEX TRIG ® COPYRIGHT 1947 BY KEUFFEL & ESSER CO. PATS. 2,500,460 2,168,056 2,170,144 2,285,722 2,422,649. These patents were issued between 1939 and 1950. They dealt with the arrangement of scales on a slide rule, in particular so that the user could solve multistep problems without having to write down intermediate settings, and with the placement of a legend to make placing the decimal point easier.
The rule fits into an orange leather case lined with chamois, which is marked on the flap: K + E. The case fits inside a green cardboard box, which has been completely wrapped in masking tape. See 2007.0181.01.01 for documentation received in the box. A label on the end of the box is marked: K + E (/) 68 1215 (/) LOG LOG DUPLEX DECITRIG (/) SLIDE RULE (/) WITH LEATHER CASE. The label is also marked: OLD (/) 4081-3S. The S indicates the sewn leather case. K&E's model 4081 differed from the 4080 in that the trigonometric scales were given in degrees and decimals of a degree instead of in degrees and minutes. In 1962, the model numbers were changed and given the prefix "68," and the ST scale was changed to an SRT scale. The 4080 with a sewn leather case would have been model 68-1318 in the new system. Thus, the rule was made before 1962 and the box was made after 1962. The serial number on the rule is consistent with a manufacturing date in the late 1950s.
The donor, Marvin Coolidge, reported that he purchased this rule in the fall of 1963 for use in a one-year slide rule course during college. He subsequently enlisted in the U.S. Air Force, where he was trained in electronics repair, a field that did not require use of this slide rule.
References: Carl M. Bernegau, "Slide Rule" (U.S. Patent 2,168,056 issued August 1, 1939); Lyman M. Kells, Willis F. Kern, and James R. Bland, "Slide Rule" (U.S. Patent 2,170,144 issued August 22, 1939); Lyman M. Kells, Willis F. Kern, and James R. Bland, "Slide Rule" (U.S. Patent 2,285,722 issued June 9, 1942); James R. Bland, "Slide Rule" (U.S. Patent 2,422,649 issued June 17, 1947); Herschel Hunt, "Slide Rule" (U.S. Patent 2,500,460 issued March 14, 1950); K + E Catalog, 42nd ed. (New York: Keuffel & Esser Co., 1954), 279; Keuffel & Esser Co., Slide Rules, Catalog 8 (Hoboken, N.J., 1962), 8-17; Clark McCoy, "Collection of Pages from K&E Catalogs for the 4081-3 Family of Slide Rules: 4080-3 & 4081-3 Family Groups," http://www.mccoys-kecatalogs.com/KEModels/ke4081-3family.htm; Walter Shawlee II, Ted Hume, and Paul Ross, "Keuffel & Esser Co. Slide Rules," Sphere Research Corporation, http://www.sphere.bc.ca/test/ke-sliderule.html.
Location
Currently not on view
date made
1954-1962
maker
Keuffel & Esser Co.
ID Number
2007.0181.01
accession number
2007.0181
catalog number
2007.0181.01
Some engineers continued to use slide rules even when they lost their sight. This is such an instrument; it may have been adapted from Keuffel & Esser's original product by the American Foundation for the Blind.
Description
Some engineers continued to use slide rules even when they lost their sight. This is such an instrument; it may have been adapted from Keuffel & Esser's original product by the American Foundation for the Blind. The ten-inch duplex rule is made from mahogany coated with white celluloid and held together with metal end pieces. It has an oversized plastic indicator with plastic edges and is held together with plastic dowels. Instead of a hairline there is a piece of wire held taut between 2 plastic pegs on the open frame of the indicator. One side of the base has LL02, LL03 and DF scales at the top and D, LL3, and LL2 scales at the bottom. The other side has LL01, L, K, A, D, DI, and LL1 scales. The slide has CF, CIF, CI, and C scales on one side and B, T, SRT, and S scales on the other. Some divisions on the A scale and both D scales on the base and the T, S, and C scales on the slide are marked with raised metal dots. Some of these dots indicate numbers in Braille.
On one side, the right end of the slide is marked in red: © (/) K + E. On the other side, the left end of the slide is marked with a serial number: 397208. The left end of the top and the bottom of the base are both marked: 208. The top edge of the rule is marked: PATS. PEND. MADE IN U.S.A. 4081-3 LOG LOG DUPLEX DECITRIG ® COPYRIGHT 1947 BY KEUFFEL & ESSER CO. PATS. 2,500,460 2,168,056 2,170,144 2,285,722 2,422,649. Keuffel & Esser used this arrangement of scales on model 4081-3 from 1955 to 1962; the serial number suggests this example was made around 1958. See MA.318482 and 1990.0687.01 for nonadapted examples of model 4081-3. The instrument is in a very dark green leather sleeve fitted to the oversized indicator.
This slide rule belonged to Moritz Otto Shollmier (1931–1972), the late husband of the donor. He was a mechanical engineer who graduated from the School of Engineering at the University of Arkansas in 1956. He lost his sight in 1961 as a result of the effects of diabetes and used this instrument for several years to design heating and air conditioning projects. He was also an avid ham radio operator.
References:
Ed Chamberlain, "Estimating K&E Slide Rule Dates," 27 December 2000, http://www.sphere.bc.ca/test/ke/320-k+e_date2.jpg.
Accession file.
Gordon Anthony, "The K&E Braille Slide Rule," Journal of the Oughtred Society 2, no. 1 (1993): 19–20.
"Keuffel & Esser Braille Slide Rule," 2006.011.001
MIT Museum, http://webmuseum.mit.edu/detail.php?t=exhibitions&type=exh&f=&s=32&record=7.
"In Memory of WA5EFL Moritz Shollmier," http://www.geocities.com/CapeCanaveral/Hangar/4073/wa5efl.html (accessed October 24, 2001).
Location
Currently not on view
date made
1955-1961
maker
Keuffel & Esser Co.
ID Number
MA.334387
catalog number
334387
accession number
313987
This ten-inch mahogany duplex linear slide rule is almost completely coated with white celluloid. The frameless glass indicator has plastic edges. On one side, the base has K and A scales at the top and D and DI scales at the bottom. The slide has B, T, SRT, and S scales.
Description
This ten-inch mahogany duplex linear slide rule is almost completely coated with white celluloid. The frameless glass indicator has plastic edges. On one side, the base has K and A scales at the top and D and DI scales at the bottom. The slide has B, T, SRT, and S scales. Divisions of angles are indicated in decimal fractions. The left side of the slide is marked with the serial number 330508, with the number 508 printed on the left side of both parts of the base.
The other side of the rule has a DF scale on the top of the base and D and L scales on the bottom of the base. The slide has CF, CIF, CI, and C scales. The top of the base is marked in red: KEUFFEL & ESSER CO.; PATS. 2,500,460 2,168,056 2,170,144 PAT PEND.; MADE IN U.S.A. The right side of the slide is marked with the K&E logo, a copyright sign, and the model number, 4071-3. The instrument fits in an orange leather case with the K&E logo on the flap. Inside the flap is written in ink: H. R. L. (/) JULY '62.
Keuffel & Esser Company of New York sold this model from 1939 to 1967. The combination of scales on this example was sold beginning in 1955, and the model was renumbered in 1962 to 68-1502. Thus, the rule was probably manufactured between 1955 and 1962. The serial number is consistent with this dating.
The donor, Alfred E. Brown, was a research chemist for Celanese Corporation, which partnered with K&E in the 1960s to produce a special version of the 68-1555 slide rule (see 1993.0357.01). However, it is not known how this rule came into Brown's possession.
References: Clark McCoy, "Collection of Pages from K&E Catalogs for the 4071-3 Family of Slide Rules," http://www.mccoys-kecatalogs.com/KEModels/ke4071family.htm; Carl M. Bernegau, "Slide Rule" (U.S. Patent 2,168,056 issued August 1, 1939); Lyman M. Kells, Willis F. Kern, and James R. Bland, "Slide Rule" (U.S. Patent 2,170,144 issued August 22, 1939); Herschel Hunt, "Slide Rule" (U.S. Patent 2,500,460 issued March 14, 1950); Walter Shawlee II, Ted Hume, and Paul Ross, "Keuffel & Esser Co. Slide Rules," Sphere Research Corporation, http://www.sphere.bc.ca/test/ke-sliderule.html; "Alfred E. Brown Chemist," The Washington Post, March 19, 2004, http://www.washingtonpost.com/wp-dyn/articles/A9676-2004Mar19_2.html.
Location
Currently not on view
date made
1955-1962
date received
1993
maker
Keuffel & Esser Co.
ID Number
1993.0482.01
accession number
1993.0482
catalog number
1993.0482.01
This ten-inch mahogany duplex slide rule is coated with white celluloid. There are LL02, LL03, DF, D, LL3, and LL2 scales on one side of the base, with CF, CIF, CI, and C scales on the slide. The right side of the slide is marked in red: © (/) K + E.
Description
This ten-inch mahogany duplex slide rule is coated with white celluloid. There are LL02, LL03, DF, D, LL3, and LL2 scales on one side of the base, with CF, CIF, CI, and C scales on the slide. The right side of the slide is marked in red: © (/) K + E. On the other side of the base, there are LL01, L, K, A, D, DI, and LL1 scales, with B, T, SRT, and S scales on the slide. The left end of the slide is marked: 320858. The left end of the top and the bottom of the base are both marked: 858. The indicator is glass, with white plastic edges held together with metal screws. Keuffel & Esser used this arrangement of scales on this model from 1955 to 1962; the serial number suggests this example was made around 1957.
The top edge of the rule is marked: PATS. PEND. MADE IN U.S.A. 4081-3 LOG LOG DUPLEX DECITRIG ® COPYRIGHT 1947 BY KEUFFEL & ESSER CO. PATS. 2,500,460 2,168,056 2,170,144 2,285,722 2,422,649. These patents were issued between 1939 and 1950. They dealt with the arrangement of scales on a slide rule, in particular so that the user could solve multistep problems without having to write down intermediate settings, and with the placement of a legend to make placing the decimal point easier.
The Keuffel & Esser Company of New York donated this slide rule to the Smithsonian in 1961. In 1959, model 4081-3 sold for $22.50. Model 4081-3, the Log Log Duplex Decitrig, differs from model 4080-3, the Log Log Duplex Trig, in that the degrees on the trigonometric scales are divided into decimals instead of into minutes. Compare to 1992.0437.01 and 2007.0181.01.
References: Carl M. Bernegau, "Slide Rule" (U.S. Patent 2,168,056 issued August 1, 1939); Lyman M. Kells, Willis F. Kern, and James R. Bland, "Slide Rule" (U.S. Patent 2,170,144 issued August 22, 1939); Lyman M. Kells, Willis F. Kern, and James R. Bland, "Slide Rule" (U.S. Patent 2,285,722 issued June 9, 1942); James R. Bland, "Slide Rule" (U.S. Patent 2,422,649 issued June 17, 1947); Herschel Hunt, "Slide Rule" (U.S. Patent 2,500,460 issued March 14, 1950); Clark McCoy, "Collection of Pages from K&E Catalogs for the 4081-3 Family of Slide Rules: 4080-3 & 4081-3 Family Groups," http://www.mccoys-kecatalogs.com/KEModels/ke4081-3family.htm; Ed Chamberlain, "Estimating K&E Slide Rule Dates," 27 December 2000, http://www.sphere.bc.ca/test/ke/320-k+e_date2.jpg; K + E Price List, Applying to the 42nd Edition Catalog (Hoboken, N.J., 1959), 73.
Location
Currently not on view
date made
1955-1962
maker
Keuffel & Esser Co.
ID Number
MA.318482
catalog number
318482
accession number
235479
This 20-inch mahogany slide rule is coated with white celluloid on both sides and held together with metal end pieces. A glass indicator has plastic edges held together with metal screws. .
Description
This 20-inch mahogany slide rule is coated with white celluloid on both sides and held together with metal end pieces. A glass indicator has plastic edges held together with metal screws. . There are LL02, LL03, DF, D, LL3, and LL2 scales on one side of the base, with CF, CIF, CI, and C scales on the slide. The right end of the slide is marked in red: © (/) K + E. On the other side of the base, there are LL01, L, K, A, D, DI, and LL1 scales, with B, T, SRT, and S scales on the slide. The left end of the slide is marked: 450243. The left end of the top and the bottom of the base are both marked: 243. Keuffel & Esser used this arrangement of scales on this model from 1955 to 1962; the serial number suggests this example was made around 1958.
The top edge of the rule is marked: PATS. PEND. MADE IN U.S.A. 4081-5 LOG LOG DUPLEX DECITRIG ® COPYRIGHT 1947 BY KEUFFEL & ESSER CO. PATS. 2,500,460 2,168,056 2,170,144 2,285,722 2,422,649. These patents were issued between 1939 and 1950. They dealt with the arrangement of scales on a slide rule, in particular so that the user could solve multistep problems without having to write down intermediate settings, and with the placement of a legend to make placing the decimal point easier.
The rule slides into an orange leather case lined with chamois. The flap is marked: K + E. Inside the flap is written: PHIL (/) KRUPEN. In 1959, model 4081-5 sold with a leather case for $50.50. Compare to ten-inch versions of model 4081, MA.318482 and MA.334387.
This slide rule was given to the Smithsonian in 1986 by the physicist Philip Krupen (1915–2001). Krupen received his BS from Brooklyn College in 1935, worked on the development of the proximity fuze during and after World War II, earned an MS in physics from The George Washington University, and spent a total of 38 years working for the U.S. government before his retirement in 1973.
References: Carl M. Bernegau, "Slide Rule" (U.S. Patent 2,168,056 issued August 1, 1939); Lyman M. Kells, Willis F. Kern, and James R. Bland, "Slide Rule" (U.S. Patent 2,170,144 issued August 22, 1939); Lyman M. Kells, Willis F. Kern, and James R. Bland, "Slide Rule" (U.S. Patent 2,285,722 issued June 9, 1942); James R. Bland, "Slide Rule" (U.S. Patent 2,422,649 issued June 17, 1947); Herschel Hunt, "Slide Rule" (U.S. Patent 2,500,460 issued March 14, 1950); Clark McCoy, "Collection of Pages from K&E Catalogs for the 4081-3 Family of Slide Rules: 4080-3 & 4081-3 Family Groups," http://www.mccoys-kecatalogs.com/KEModels/ke4081-3family.htm; Ed Chamberlain, "Estimating K&E Slide Rule Dates," 27 December 2000, http://www.sphere.bc.ca/test/ke/320-k+e_date2.jpg; K + E Price List, Applying to the 42nd Edition Catalog (Hoboken, N.J., 1959), 73; Dieter von Jezierski, Slide Rules: A Journey Through Three Centuries, trans. Rodger Shepherd (Mendham, N.J.: Astragal Press, 2000), 71–75; "Philip Krupen," The Washington Post, February 23, 2001, B07.
Location
Currently not on view
date made
1955-1962
date received
1986
maker
Keuffel & Esser Co.
ID Number
1986.0790.03
accession number
1986.0790
catalog number
1986.0790.03
This ten-inch aluminum linear slide rule is coated with white plastic (the "traditional" color). It has a nylon indicator and is held together with stamped aluminum squared posts. The front of the base has K, A, D, and DI scales, with B, ST, T, S, and C scales on the slide.
Description
This ten-inch aluminum linear slide rule is coated with white plastic (the "traditional" color). It has a nylon indicator and is held together with stamped aluminum squared posts. The front of the base has K, A, D, and DI scales, with B, ST, T, S, and C scales on the slide. The left end of the slide is marked: MODEL (/) N1010-T (/) TRIG. The right end of the slide bears the style of Pickett logo used between 1958 and 1962. The number 74 appears above the logo.
The back of the base has DF, D, DI, and L scales, with CF, CIF, CI, and C scales on the slide. The left end of the slide is marked: COPYRIGHT 1959 © (/) PATENT APPLIED FOR. The right end of the slide is marked: PICKETT & ECKEL, INC. (/) 272.
The slide rule fits into a clear plastic bag and then into an orange-brown leather case lined in clear plastic. The triangular Pickett logo is embossed below the slot for the case's flap, and there is a metal ring on the back of the case for attaching to a belt. The slide rule arrived in a white, black, red, and yellow cardboard box. The 1958-1962 Pickett logo is superimposed on a model of the atom on the box. The top and bottom of the box are marked with several of the instrument's selling points: lifetime accuracy, all metal permanence; select a handy pocket size rule too (/) matched for your convenience by Pickett; micro divided scales; world's most accurate; safety liner case; completely guaranteed; complete instruction manual; slider tension springs.
Inside the box are four pieces of paper: a welcome note from company president John W. Pickett, marked Form 247; care instructions for the rule, marked Form 543; a guarantee, which indicates this instrument has serial number 252372; and a promotional flyer on Pickett's "eye-saver" yellow color, marked Form 225-A. See 1993.0559.01.01 for an instruction manual received in the box. One end of the box is marked: Pickett SLIDE RULE (/) all metal • guaranteed (/) A PRODUCT OF AMERICAN ENGINEERING AND MANUFACTURING. The other end of the box has a product label, which notes the Model N-1010-T Trig Slide Rule has the: Approved Scale Arrangement for basic work in all fields (Schools, Business, Industry) where Log Log scales are not needed.
The logo, nylon indicator with flat lens, straight style of posts, and company addresses in Chicago and Alhambra, Calif., are all consistent with a date around 1960. However, according to the donor, the slide rule was given to him by his parents as a Christmas gift in 1944.
References: Alan Boardman, "Recollections of a Pickett Industries Employee," Journal of the Oughtred Society 16, no. 2 (2007): 8; Walter Shawlee, "Pickett Slide Rules," http://www.sphere.bc.ca/test/pickett.html; Dieter von Jezierski, Slide Rules: A Journey Through Three Centuries, trans. Rodger Shepherd (Mendham, N.J.: Astragal Press, 2000), 75–76.
Location
Currently not on view
date made
ca 1960
maker
Pickett & Eckel, Incorporated
ID Number
1993.0559.01
accession number
1993.0559
catalog number
1993.0559.01
This five-inch "eye saver" yellow aluminum linear slide rule has a nylon indicator and is held together with stamped aluminum contoured posts. The front of the base has LL1, A, D, DI, and K scales, with B, ST, T, S, and C scales on the slide.
Description
This five-inch "eye saver" yellow aluminum linear slide rule has a nylon indicator and is held together with stamped aluminum contoured posts. The front of the base has LL1, A, D, DI, and K scales, with B, ST, T, S, and C scales on the slide. The left end of the slide is marked: MODEL (/) N600-ES (/) LOG LOG (/) SPEED RULE. The right end of the slide bears the form of the Pickett logo that was used between 1958 and 1962. The number 81 is printed above the logo, and MADE IN U.S.A. is printed below it.
The back of the base has LL2, DF, D, and LL3 scales, with CF, Ln, L, CI, and C scales on the front of the slide. The left end of the slide is marked: PICKETT (/) ALL METAL (/) SLIDE RULES. The right end of the slide is marked: PICKETT & ECKEL, (/) INC. (/) CHICAGO, ILL. (/) ©1962. The instrument fits in a red-orange leather case with a clip to slide over a pocket or belt. A leather strip above the clip is stamped in gold with the Pickett triangular logo and PAT. PEND. Raising the strip pulls the rule out of the case.
On January 26, 1959, John W. Pickett applied for a design patent for a slide rule case that resembles the case for this object. The patent was granted on April 5, 1960. It seems likely that the date of this rule is relatively close to the copyright date of 1962. Pickett was the son of company founder Ross C. Pickett and served as president of the firm from 1957 to 1967. For early company history, see 1979.0601.02. The company began manufacturing aluminum slide rules in Alhambra, Calif., in the early 1950s, while retaining offices in Chicago, and changed from glass to nylon indicators in 1958. In 1964, the firm moved to Santa Barbara, Calif., and changed its name from Pickett & Eckel, Inc., to Pickett Industries. In the mid-1970s, Pickett moved to Nogales, Mexico, ceased making slide rules, and was gradually subsumed into Chartpak, Inc., a maker of art supplies and office products now located in Leeds, Mass.
Its compact size and large number of scales made this model popular with engineers who had excellent vision. The Pickett 600-ES was carried on the first five Apollo flights. See the National Air and Space Museum's inventory number A19840160000.
References: John W. Pickett, "Slide Rule Case" (U.S. Patent D187,632 issued April 5, 1960); International Slide Rule Museum, "Pickett All-Metal Slide Rules," http://sliderulemuseum.com/SR_Dates.htm#Pickett; Michael Freudiger, et al., "Mathematics on the Moon: The 'Apollo' Pickett," Journal of the Oughtred Society 10, no. 2 (2001): 15–18; Eric Marcotte, "Pickett Slide Rules," http://www.sliderule.ca/pickett.htm.
Location
Currently not on view
date made
ca 1962
maker
Pickett & Eckel, Incorporated
ID Number
1998.0119.02
catalog number
1998.0119.02
accession number
1998.0119
This ten-inch aluminum linear slide rule has a yellow ("eye saver") coating and a nylon indicator. The front of the base has L, DF, D, and DI scales, with B, ST, T, S, and C scales on the slide. The left end of the slide is marked: MODEL (/) N1010-ES (/) TRIG.
Description
This ten-inch aluminum linear slide rule has a yellow ("eye saver") coating and a nylon indicator. The front of the base has L, DF, D, and DI scales, with B, ST, T, S, and C scales on the slide. The left end of the slide is marked: MODEL (/) N1010-ES (/) TRIG. The right end of the slide has the style of Pickett logo used between 1958 and 1962, with MADE IN U.S.A. printed below the logo.
The back of the base has K, A, D, and DI scales, with CF, CIF, CI, and C scales on the slide. The left end of the slide is marked: COPYRIGHT 1959© (/) PATENT APPLIED FOR. The right end of the slide is marked: PICKETT INC. (/) Santa Barbara, Calif. Compare to 1993.0559.01.
A black leather case is lined in pink plastic. The triangular Pickett logo stamped in gold below the slot for the case's flap is wearing away. The back of the case has a metal ring for attaching to a belt. Inside the flap is the name and address of David D. Goldberg, who was apparently the first owner of the instrument. It then passed to Janis Popowicz, who donated the rule to the Smithsonian while she was technician in the Division of Mathematics from September 1977 to April 1978. She used it as a high school physics student.
As is the case for many Pickett slide rules (e.g., 1991.0445.02), the dating for this instrument is ambiguous. The copyright date, logo, shape of the posts, and location of the grooves (on the slide instead of on the base) are all consistent with a date between 1958 and 1962. However, Pickett & Eckel only moved to Santa Barbara, Calif., and took the new name of Pickett Industries in 1964. The logo changed in 1962 and again in 1964. See the company history with 1998.0119.02.
References: Rodger Shepherd, "Pickett Metal Slide Rules," Journal of the Oughtred Society 1, no. 1 (1992): 5–8; James A. Coontz, "You Think You Have Moving Day Problem?" Los Angeles Times, January 16, 1964, B8; Michael P. O'Leary, "Pickett from a Manufacturing Perspective," Journal of the Oughtred Society 10, no. 1 (2001): 13–14; Maurice L. Hartung, A Teaching Guide for Slide Rule Instruction (Chicago: Pickett & Eckel, Inc., 1960), http://www.sphere.bc.ca/test/pickett/pickett_training.pdf.
Location
Currently not on view
date made
ca 1962
maker
Pickett Industries
ID Number
1977.1113.01
catalog number
336446
accession number
1977.1113
This ten-inch duplex slide rule is made from mahogany coated with white celluloid and is held together with metal end pieces. The indicator is glass with plastic edges held together with metal screws.
Description
This ten-inch duplex slide rule is made from mahogany coated with white celluloid and is held together with metal end pieces. The indicator is glass with plastic edges held together with metal screws. One side of the base has LLO1, L, K, A, D, DI, and LL1 scales, with B, T, SRT, and S scales on the slide. The left end of both parts of the base is marked: 092, and the left end of the slide is marked: 991092. The other side of the base has LLO2, LLO3, DF, D, LL3, and LL2 scales, with CF, CIF, CI, and C scales on the slide. The right side of the slide is marked: © (/) K+E. This form of the K&E logo dates to 1949.
The top edge of the rule is marked: PATS. PEND.; MADE IN U.S.A; 68 1210 LOG LOG DUPLEX DECITRIG ®; COPYRIGHT 1947 BY KEUFFEL & ESSER CO.; PATS. 2,500,460 2,168,056 2,170,144 2,285,722 2,422,649. The rule has a green leather case marked on the flap: K+E. Inside the flap is written in ink: Howard (/) Ebenstein; Pratt (/) Institute (/) 1965. Howard Ebenstein acquired this slide rule as a student in mechnical engineering at Pratt Institute in New York City. He went on to a career in public service with the the Department of the Navy, Peace Corps, and the District of Columbia Energy Office.
Keuffel & Esser of New York converted its model numbers to the 68 series in 1962. It advertised the model 68–1210 in its 1962, 1966, 1967, and 1972 catalogs. In 1962, the rule came with a case with a belt loop and a hardcover manual. By 1967, there was an option to purchase the rule with a case without a belt loop and a softcover manual. Thus, this example was probably produced closer to 1965 than to 1962. The serial number is also consistent with this date. For earlier versions of this slide rule, sold as the model 4081, see MA.318482, MA.334387, 1990.0687.01, and 1986.0790.03. For instructions, see 1987.0085.02.
References: Clark McCoy, ed., "K&E Catalogs and Price Lists for Slide Rules," http://www.mccoys-kecatalogs.com/KEmain.htm; Wayne E. Feely, "K & E Slide Rules," The Chronicle of the Early American Industries Association 49, no. 5 (June 1996): 50–52.
Location
Currently not on view
date made
1965
maker
Keuffel & Esser Co.
ID Number
1987.0085.01
accession number
1987.0085
catalog number
1987.0085.01

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