| National Museum of American History

This yellowed ivory instrument has two rectangular arms with flat edges and is held together by a circular brass hinge. The lower arm is broken. The scales run from top to bottom on each arm.

Description: This yellowed ivory instrument has two rectangular arms with flat edges and is held together by a circular brass hinge. The lower arm is broken. The scales run from top to bottom on each arm. On one side, each arm has a sine scale, running from 10 to 80 degrees; a tangent scale, running from 45 to 75 degrees; and a second tangent scale, running from 10 to 45 degrees. Spanning both arms on the outer edge are three scales: log tangent, running from 3 to 45 degrees; log sine, running from 1 to 70 degrees; and logarithmic numbers, running from 1 to 10 twice. A double line separates these scales from the inner, diagonal set of scales. The top face of the instrument has a scale of equal parts that divides one foot into 100 increments and runs from 90 to 10. There is no maker's mark.; The other side has a double scale along the fold line for regular polygons, labeled POL and running from 12 to 4 sides. Each arm has a scale of equal parts, running from 1 to 10 and labeled L; a secant scale, running from 20 to 75 and labeled s; and a scale of chords, running from 10 to 60 and labeled C. The scales for dialing typically found on 18th-century English-style sectors are not present. Spanning both arms on the outer edge is a scale of inches, running from 12 to 1 and divided to tenths of an inch. Compare to MA.321755, MA.333937, and 1985.0580.06.; This sector may have been used at the New York Meteorological Observatory in Central Park, established and directed by Daniel Draper from 1868 to 1911.; References: Christopher J. Sangwin, "Edmund Gunter and the Sector," January 21, 2003, http://web.mat.bham.ac.uk/C.J.Sangwin/Sliderules/sector.pdf; Robert S. Harding and Jeffrey L. Tate, "Draper Family Collection, ca. 1826–1936," Archives Center, National Museum of American History, http://amhistory.si.edu/archives/d8121.htm.
Location: Currently not on view

date made: 19th century

ID Number: MA.335351
accession number: 304826
catalog number: 335351

This ten-inch mahogany duplex linear slide rule is coated with celluloid on the front and back only; the edges are bare. The indicator is glass with metal screws and plastic sides. On both sides, there is an A scale on the top of the base and a D scale on the bottom of the base.

Description: This ten-inch mahogany duplex linear slide rule is coated with celluloid on the front and back only; the edges are bare. The indicator is glass with metal screws and plastic sides. On both sides, there is an A scale on the top of the base and a D scale on the bottom of the base. One side of the slide has B and C scales; there are BI and CI scales on the other side.; On the front (CD) side, the bottom of the base is marked: KEUFFEL & ESSER CO. N.Y.; PAT. JUNE 5. '00 DEC. 22. '08. The slide is marked on the left side: < 4071 >. The top edge of the indicator is marked: K&E.CO.N.Y. (/) PAT.8.17.15. The back of the rule is not marked.; Keuffel & Esser of New York sold this model of slide rule from 1901 to 1917. Head of manufacturing Willie Keuffel took out patents for improving the ability to adjust duplex slide rules in 1900 and 1908. The "frameless" style of indicator found on this example was introduced in 1915, after Keuffel's patent for that improvement was granted on August 15 of that year. Assuming that the indicator is original, the rule dates from 1915–1917. It sold for $5.00. Compare this example, donated to the Smithsonian by K&E in 1961, to the earlier versions MA.318477 and MA.326613.; References: Willie L. E. Keuffel, "Slide-Rule" (U.S. Patent 651,142 issued June 5, 1900); Willie L. E. Keuffel, "Slide-Rule" (U.S. Patent 907,373 issued December 22, 1908); Willie L. E. Keuffel, "Slide-Rule Runner" (U.S. Patent 1,150,771 issued August 17, 1915); Catalogue of Keuffel & Esser Co., 35th ed. (New York, 1915), 302–303.
Location: Currently not on view

date made: 1915-1917

maker: Keuffel & Esser Co.

ID Number: MA.318475
catalog number: 318475
accession number: 235479

The scales on this 22-inch, two-sided wooden slide rule are printed on paper. The front has two scales on the left end of the base labeled B and C and two scales labeled A on the left end of the slide. These scales run half the length of the instrument.

Description: The scales on this 22-inch, two-sided wooden slide rule are printed on paper. The front has two scales on the left end of the base labeled B and C and two scales labeled A on the left end of the slide. These scales run half the length of the instrument. The B and two A scales are identical, divided logarithmically from left to right and running from 1 to 10. The C scale is divided logarithmically from right to left and runs from 10 to 1. It is labeled RECIPROCALS.; The right end of the base has two D scales, both labeled ROOTS, with two additional A scales on the right end of the slide. The A scales are divided logarithmically from left to right and run from 1 to 10. The top D scale runs from 1 to 3.16 and shows square roots of the numbers on the A scale below it. The bottom D scale runs from 3.16 to 10 and shows square roots of the numbers on the A scale above it, between 10 and 100. Written in pencil on the back of the slide and underneath the slide is the number 1096.; The back of the rule contains two scales on the base labeled F and two scales on the slide labeled E. The top F scale runs the length of the scale and is divided logarithmically from 1 to 10. The sections between 1 and 2, between 2 and 3, between 3 and 4, and between 4 and 5 are subdivided. The lower F scale is similarly divided, but starts from the center of the rule (running from the square root of 10, or 3.16, to 10 and then from 1 to the square root of 10). The E scales are identical to the adjacent F scales. Written in pencil on the back of the slide and underneath the slide is the number 1097.; The bottom of the base on both sides is marked: Patented July 2, 1901. The top edge of the rule is marked: THE ENGINEERS (/) SLIDE RULE. It is also marked: From E. M. Scofield, Bridge Engineer. (/) Sta. A, – Youngstown, – Ohio. (/) Rule sent prepaid on receipt of price. (/) Factory, – Youngstown, Ohio. The paper pasted on this edge also has the formula ex/f, a description of how to solve this formula with the instrument, and tables of equivalents. The bottom edge of the rule gives seventeen more formulas and instructions. It is marked: DIRECTIONS FOR SCALES A • B • C & D (/) FOR "Op." READ "OPPOSITE" (/) FOR "—" READ "ON SCALE" (/) FOR "Ans." READ "FIND ANSWER" (/) FOR LAST SIX PROBLEMS REVERSE SLIDE.; Edson Mason Scofield (1867–1939) developed this rule in 1891, while he worked for Edwin Thacher (inventor of the cylindrical slide rule bearing his name; see, for example, MA.312866). Thacher applied for a patent on the design in 1900 and assigned a half-interest to Scofield when the patent was issued in 1901. According to the instrument, Scofield may have distributed the rule himself. It was also sold by Eugene Dietzgen Company of Chicago from about 1901 through at least 1931. The price for model 1787 ranged from $5.00 to $7.00. By 1926, Dietzgen marked the rule with its company name. This instrument is identical to MA.325990.; John N. Welsh (1904–1999), the donor of this slide rule, was a chemical engineer who obtained his B.S. from the Carnegie Institute of Technology in 1925. He was associated with Hall Laboratories, Inc. of Pittsburgh (later CALGON) from 1939 through at least 1968. By 1972, when this slide rule was briefly placed on exhibit, Welsh was living in Florida.; References: Edwin Thacher, "Slide Rule" (U.S. Patent 677,817 issued July 2, 1901); Catalogue & Price List of Eugene Dietzgen Co., 7th ed. (Chicago, 1904), 173; Catalog of Eugene Dietzgen Co., 12th ed. (Chicago, 1926), 177; Conrad Schure, "The Scofield-Thacher Slide Rule," Journal of the Oughtred Society 3, no. 1 (1994): 20–25; Peter M. Hopp, Slide Rules: Their History, Models, and Makers (Mendham, N.J.: Astragal Press, 1999), 161; Who's Who in Engineering (New York and West Palm Beach: Lewis Historical Publishing Co., 1964), 1996.
Location: Currently not on view

date made: 1901-1926

maker: Scofield, E. M.

ID Number: MA.333710
catalog number: 333710
accession number: 300658

The arms of this brass instrument have straight edges, but the hinge is decorated with a straight and squiggly lines.

Description: The arms of this brass instrument have straight edges, but the hinge is decorated with a straight and squiggly lines. One side has a double scale of chords that runs from 10 to 130; a double scale for "Les Solides" that runs from 1 to 60; and a double scale for the specific weights of four metals, marked with their symbols. Two holes are drilled on either side of the 80 mark on the scales of chords on the lower arm. The outer edge of the lower arm has a scale that runs from 4 to 24 and is labeled "pd des boulets" (for the weight of iron shot).; On the other side, the outer edge has a scale that runs from 4 to 24 and is labeled "Cbres des Pieces" (for the size of iron shot, given the diameter of the barrel and the weight of the shot). There are double scales of equal parts, running from 10 to 200; for architectural drawings, running from 10 to 60; and for inscribed regular polygons, from 12 sides to three sides. Compare to MA.321676 and 1985.0580.04.; According to the accession file, the donor collected this instrument in Mobile, Ala., around 1898 and sent it to the Smithsonian in 1936.
Location: Currently not on view

date made: 18th century

ID Number: MA.311165
catalog number: 311165
accession number: 141741

This desktop slide rule is in a wooden case that is significantly deteriorated on its inside. The rule has a cylindrical brass drum covered with paper printed with forty A scales. A wooden handle is fastened to each end of the drum.

Description: This desktop slide rule is in a wooden case that is significantly deteriorated on its inside. The rule has a cylindrical brass drum covered with paper printed with forty A scales. A wooden handle is fastened to each end of the drum. The drum fits in an open rotating brass frame; twenty brass slats span the frame. The right side of the paper on the drum is printed in italics: Patented by Edwin Thatcher [sic], C.E. Nov. 1st 1881. Divided by W. F. Stanley, London, 1882. Made by Keuffel & Esser Co. N.Y.; The slats are lined with cloth and covered with paper. Each slat is printed with two B and two C scales. The first A scale runs from 100 to 112; the fortieth runs from 946 to 100 to 105. The first B scale runs from 100 to 112; the fortieth runs from 946 to 100 to 105. The first C scale runs from 100 to 334; the fortieth runs from 308 to 305.; The frame is screwed to a mahogany base. A paper with instructions is glued to the top front of the base. An ivory label for Keuffel & Esser Co. is screwed to the front right corner. The top back of the base is engraved: KEUFFEL & ESSER Co (encircling N.Y.); 4012 (/) 1689; TRADE MARK (below the K&E lion logo). Another ivory K&E label is fastened inside the lid of the case. A paper K&E label pasted inside the lid is stamped in faded purple ink: No. 4013 (/) Serial 1689. Written in pencil is: Mar 22/07.; The Thacher cylindrical slide rule was sized for a desk, but its scales were equivalent to those on a conventional slide rule over 59 feet long. It had scales for multiplication, division, and squares and square roots. There were no trigonometric scales.; Keuffel & Esser sold model 4012 from 1900 to about 1950. The markings and serial number indicate this example dates to 1907. Model 4012 cost $35.00 in 1909. The U.S. Department of Agriculture transferred this example to the Smithsonian in 1964.; See also MA.312866, MA.326628, and MA.323504.; References: Wayne E. Feely, "Thacher Cylindrical Slide Rules," The Chronicle of the Early American Industries Association 50 (1997): 125–127; Catalogue of Keuffel & Esser Co., 33rd ed. (New York, 1909), 304.
Location: Currently not on view

date made: 1907

maker: Keuffel & Esser Co.

ID Number: MA.322730
accession number: 252315
maker number: 1689
catalog number: 322730

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 ten-inch wood slide rule is faced with white celluloid on both sides. The indentations on the metal end pieces face in, as was typical for Keuffel & Esser slide rules manufactured between 1901 and 1913; compare to MA.326613.

Description: This ten-inch wood slide rule is faced with white celluloid on both sides. The indentations on the metal end pieces face in, as was typical for Keuffel & Esser slide rules manufactured between 1901 and 1913; compare to MA.326613. The brass indicator is in the double chisel style (with an open interior), used from 1891 to about 1909. See also MA.318477 and 1977.0370.01. The edge of the indicator is marked: KEUFFEL & ESSER CO. (/) NEW-YORK.; The slide has two parts, which fit between the three parts of the base. On one side, the top of the base has an A scale; the top of the slide has B and C scales; the middle of the base has D and DF scales; the bottom of the slide has C and S scales; and the bottom of the base has an A scale. The bottom of the base is marked: KEUFFEL & ESSER Co NEW-YORK. On the left edge of the rule, the top and bottom of the base and the slide are all stamped: 5.; On the other side, the top of the base has an A scale; the top of the slide has BI and CI scales; the middle of the base has D and DF scales; the bottom of the slide has CIF, L, and T scales; and the bottom of the base has a D scale. On both sides, the DF scale is unlettered. The CIF scale is incorrectly lettered "CI." Unlike later slide rules, which start at pi, the folded scales on this rule (CF, CIF, and DF) start at the square root of 10 (approximately 3.16).; The bottom of the base on the back is marked in red: PAT. OCT. 6. 1891 & MAR. 21. 1899. The second patent date is in a different font and size than the first. The first patent refers to William Cox's invention of the duplex slide rule, which K&E used to launch its manufacture of American slide rules. William L. E. Keuffel, the company's head of manufacturing, received the second patent for the design of the dual slide seen in this rule.; K&E only used the dual slide on its Universal slide rule, suggesting the concept was not as useful as the company hoped. The dual slide also addressed a limitation of K&E dividing engines, which were only able to cut scales on the edges of rules. Once K&E improved its dividing engines, this solution was no longer necessary. The Universal slide rule sold as model 4090 from 1900 to 1905 and as the model 4090N from 1906 to 1911. From 1900 to 1902, it had a brass chisel indicator; from 1903 to 1905, it had a German silver chisel indicator; and from 1906 to 1911 it had a glass clam shell indicator. This example thus dates to 1900–1902. It sold for $20.00.; References: William Cox, "Engineer's Slide-Rule" (U.S. Patent 460,930 issued October 6, 1891); W. L. E. Keuffel, "Slide Rule" (U.S. Patent 621,348 issued March 21, 1899); Catalogue of Keuffel & Esser Co., 30th ed. (New York, 1900–1901), 297; Catalogue of Keuffel & Esser Co., 31st ed. (New York, 1903), 307; Bob Otnes and Bob DeCesaris, "The K&E Universal Slide Rule," Journal of the Oughtred Society 10, no. 2 (2001): 45–48; 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.
Location: Currently not on view

date made: 1900-1902

maker: Keuffel & Esser Co.

ID Number: MA.318478
catalog number: 318478
accession number: 235479

This 20-inch mahogany one-sided slide rule is coated with white celluloid. The top edge is beveled and has a simply divided scale 20 inches long that is divided to sixteenths of an inch. The base has A, D, and K scales.

Description: This 20-inch mahogany one-sided slide rule is coated with white celluloid. The top edge is beveled and has a simply divided scale 20 inches long that is divided to sixteenths of an inch. The base has A, D, and K scales. One side of the slide has B, CI, and C scales; S, L, and T scales are on the other side. The A and B scales are divided logarithmically from 1 to 10 twice in the usual manner. The C and D scales are divided logarithmically once from 1 to 10 in the length of the scales in the usual manner. The CI scale is divided logarithmically from 1 to 10 the length of the scale, going in the opposite direction from the other scales. The K scale is divided logarithmically three times in the length of the scale, for use in finding cubes and cube roots. The S scale gives the sines of angles from less than 40 minutes to 90 degrees. The L scale is a scale of equal parts running from 0 to 10. The T scale gives tangents of angles from somewhat less than 6 degrees to 45 degrees.; The front edge has a simply divided scale 50 centimeters long that is divided to millimeters. The indicator is of the "frameless" glass style with plastic edge pieces and metal screws. A paper table of equivalents and slide rule settings, based on U. S. Bureau of Standards Circular No. 47, is pasted to the back of the rule. See also 1981.0933.05 and 1999.0254.01. The instrument fits in a cardboard case covered with black leather that fastens with a snap.; The top of the base is marked in red: PAT. JUNE 5, 1900; KEUFFEL & ESSER CO. N.Y.; MADE IN U.S.A. The right end of the slide has the model number in red: < N4053-5 >. The left end of the other side of the slide and the scale in centimeters are marked with a serial number: 295836. The bottom edge of the indicator is marked: K&E.CO.N.Y. (/) PAT.8.17.15. The flap of the case is marked: K & E (/) POLYPHASE (/) SLIDE RULE (/) 4053–5. The snap on the case is marked: KEUFFEL & ESSER CO. (/) NEW YORK.; Keuffel & Esser sold an earlier form of this slide rule, with no beveled edge at the top, from 1913 through 1922. The new form of the instrument—with the beveled edge, the K scale on the base instead of on the bottom edge, and the centimeter scale on the bottom edge—sold from 1923 to 1953. The style of the indicator on this slide rule was in use from 1915 through 1934. Illustrations of the 4053 line of slide rules in K&E catalogs depict the patent date of June 5, 1900, from 1925 through 1934. Thus, this example likely dates to 1925–1934; the serial number suggests a date around 1930. Compare also to 1981.0922.05. For documentation, see MA.304213.05. The Interstate Commerce Commission discarded this rule as surplus material in 1963.; References: Willie L. E. Keuffel, "Slide-Rule" (U.S. Patent 651,142 issued June 5, 1900); Willie L. E. Keuffel, "Slide-Rule Runner" (U.S. Patent 1,150,771 issued August 17, 1915); Catalogue of Keuffel & Esser Co., 34th ed. (New York, 1913), 300; Catalogue of Keuffel & Esser Co., 35th ed. (New York, 1915), 300; Keuffel & Esser Co., Slide Rules & Calculating Instruments (New York, 1925), 6; Keuffel & Esser Co., Slide Rules & Calculating Instruments (New York, 1934), 6; Catalogue of Keuffel & Esser Co., 38th ed. (New York, 1936), 312; Ed Chamberlain, "Estimating K&E Slide Rule Dates," 27 December 2000, http://www.sphere.bc.ca/test/ke/320-k+e_date2.jpg.
Location: Currently not on view

date made: 1925-1934

maker: Keuffel & Esser Co.

ID Number: MA.321780
catalog number: 321780
accession number: 246883

This wooden ten-inch Mannheim slide rule is faced with white celluloid. The top edge is beveled and has a scale of inches divided to sixteenths of an inch. The bottom edge is flat and has a scale of centimeters divided to millimeters.

Description: This wooden ten-inch Mannheim slide rule is faced with white celluloid. The top edge is beveled and has a scale of inches divided to sixteenths of an inch. The bottom edge is flat and has a scale of centimeters divided to millimeters. The base has A and D scales, with B and C scales on one side of the slide and S, L, and T scales on the other side of the slide. The L scale is not lettered. The base underneath the slide is marked: EUGENE DIETZGEN CO. CHICAGO–NEW YORK (/) W. F. M. It is also marked: PAT. JUNE 28 1898. The indicator is glass in a metal frame. A paper glued to the back of the rule gives the properties of various substances and equivalents of various weights and measures. Carved into the back is: W.F.M. 1907.; The base of the rule is cut lengthwise into two sections that are joined together by invisible springs. This was intended to create more uniform resistance to the motion of the rule (even if it is fully extended) and to make it possible to straighten the parts of the rule by scraping, should it become warped. A cardboard box covered with burgundy leather is marked: The Mack Improved Slide Rule (/) NO. 1765 (/) EUGENE DIETZGEN CO. (/) CHICAGO. NEW YORK.; This rule is named for John Givan Davis Mack (1867–1924), an early member of the engineering faculty at the University of Wisconsin who taught from 1893 to 1915. On June 28, 1898, he received U.S. Patent 606388 for dividing the base of a slide rule and rejoining the pieces with springs. He assigned the patent to the Eugene Dietzgen Company of Chicago, which first sold a slide rule built on Mack's patent in 1898 and offered this version from 1902 to 1912 for $4.50.; The carved initials are those of the owner, the spectroscopist William F. Meggers (1888–1966), who was long associated with the U.S. National Bureau of Standards. He received his B.A. in physics from Ripon College in 1910, his M.A. in physics from the University of Wisconsin in 1916, and his Ph.D. in physics, mathematics, and astronomy from Johns Hopkins University in 1917. It seems likely that he acquired this rule as a student. For a less precise slide rule associated with Meggers, see 293320.2820. For later slide rule instructions distributed by Dietzgen, see 1981.0933.07.; References: Catalogue & Price List of Eugene Dietzgen Co., 7th ed. (Chicago, 1904), 171; Rodger Shepherd, "Some Distinctive Features of Dietzgen Slide Rules," Journal of the Oughtred Society 5, no. 2 (1996): 42–45; Peter M. Hopp, Slide Rules: Their History, Models, and Makers (Mendham, N.J.: Astragal Press, 1999), 159–160, 276; J. G. D. Mack Papers, University of Wisconsin Archives: U. S. Patent 606388.
Location: Currently not on view

date made: 1907

maker: Eugene Dietzgen Company

ID Number: MA.335270
catalog number: 335270
accession number: 314637

This line of position computer, or mechanical navigator, is essentially a circular slide rule for determining one's location, either from morning or afternoon sightings for longitude or from the St. Hilaire method of finding the line of position.

Description: This line of position computer, or mechanical navigator, is essentially a circular slide rule for determining one's location, either from morning or afternoon sightings for longitude or from the St. Hilaire method of finding the line of position. It has a circular black steel base, a green felt cushioning ring, an engraved brass disc, and a yellowed and warped celluloid disc. The metal and plastic arm that extends over the celluloid disc has a brass thumbscrew at the outer edge. The celluloid disc and arm can rotate together or independently.; The brass disc is calibrated logarithmically in several concentric rings: from 80 to 0 degrees by minute in both directions (altitudes, adjusted by latitude and declination), from 0 to 500 by 1 (numbers), from 100/10/1 to 600/60/6 (logarithms), from 0 to 12 hours (hour angles), from 0 to 70 degrees by 1 X 2 (declinations), from I to XII by I (hour angles), and from 0 to 180 degrees (altitudes and azimuths).; The computer is housed in a square wooden case (lock broken and handle missing) with doors that open from the top. It appears to be impossible to remove the computer from the case. Two copies of an instructional flyer are stored separately (MA.320413.1). These describe the computer as built in two sizes, for military aircraft and for battleships. It is not clear, though, whether the computer was able to place a ship close enough to its actual position (within 0.5 to 9.6 miles, according to the examples in the flyer) to be of use for military purposes around the time of World War I. The scarcity of surviving examples suggests the government and general public had little interest in the instrument. Indeed, aviators preferred inspection tables over slide rules for navigation.; The instrument is engraved near the center: LINE OF POSITION COMPUTER (/) DESIGNED BY (/) CHAS. LANE POOR (/) NEW YORK, U.S.A. (/) PATENT APPLIED FOR.; This computer was sold by the nautical instrument firm founded in 1850 by T. S. & J. D. Negus of New York City. It was invented between 1914 and 1918 (the date of his patent application) by Charles Lane Poor (1866–1951), who earned a Ph.D. under Simon Newcomb at The Johns Hopkins University in 1892. Poor taught at Johns Hopkins until 1899, when he took over his father’s print works in New Jersey. From 1903 to 1944, Poor was professor of celestial mechanics at Columbia University. He was a critic of Einstein’s theory of relativity and an avid yachtsman.; References: Charles Lane Poor, "Navigation Instrument" (U.S. Patent 1,308,748 issued July 1, 1919); Charles Lane Poor, Simplified Navigation for Ships and Aircraft (New York: The Century Co., 1918); Richard Berendzen and Richard Hart, "Poor, Charles Lane," Dictionary of Scientific Biography xi:83–84; National Cyclopaedia of American Biography xxxviii:614; Ronald van Riet, "Position Line Slide Rules: Bygrave and Höhenrechenschieber," https://sites.google.com/site/sliderulesite/position-line-slide-rules.
Location: Currently not on view

date made: 1914-1918

maker: Negus, T. S. & J. D.

ID Number: MA.320413
catalog number: 320413
accession number: 242377

This is an eight-inch, four-sided boxwood slide rule used for measuring and taxing barrels of liquid. On one end of the rule, the slides on each side have been labeled with the four Roman numerals, I, II, III, and IV.

Description: This is an eight-inch, four-sided boxwood slide rule used for measuring and taxing barrels of liquid. On one end of the rule, the slides on each side have been labeled with the four Roman numerals, I, II, III, and IV. On side I, the base has logarithmic scales that run from 1 to 8 and from 8 to 100. It is labeled Seg S^t (Segments Standing) at the top left and SS at the bottom right. The slide has two identical C scales, logarithmically divided from 1 to 9. This side was used to estimate the volume of a barrel that was standing vertically and partially filled. The back of the slide lists calculating factors used in computing taxes on various liquors. For instance, the duty on one barrel of vinegar was equivalent to the duty on 7.56 barrels of small beer.; On side II, the base has logarithmic scales that run from 0 to 4 and from 4 to 100. The bottom right corner is labeled SL (Segments Lying) for estimating the volume of a partially filled barrel lying on its side. The slide has two identical B scales, logarithmically divided from 1 to 10. The point 231 is marked W, showing the number of cubic inches in a wine gallon, and pi (314) is marked with a C. The back of the slide has a table of gauge points for converting between volumes in cubic inches and numbers of gallons for substances in square or circular containers.; On side III, the base has an A scale, logarithmically divided from 1 to 10, and an MD (Malt Depth) scale that runs logarithmically in the opposite direction from somewhat less than 3 to 20. Point 2150 on the A scale is marked MB, for the number of cubic inches in a malt bushel, and point 282 is marked A, for the number of cubic inches in an ale gallon. The slide has two identical B scales, logarithmically divided from 1 to 9. The back of the slide has a scale of inches, a scale labeled Spheroid, and a scale labeled 2^d Variety. These scales are for determining the diameters of two different shapes of barrels. Underneath the slide is marked: LEWIS & BRIGGS : Makers. N^o. 52. BOW. LANE. Cheapside. LONDON.; On side IV, the base has a D scale, logarithmically divided from 1 to 3.2 and from 3.2 to 10. Point 17.15 is marked WG, for the diameter in inches of a cylinder that contains one gallon of wine when filled to a depth of one inch. Point 18.95 is marked AG for the diameter of a cylinder containing one gallon of ale. Point 46.3 is marked MS, for the side of a square vessel that contains a solid bushel per inch of depth, and point 52.32 is marked MR, for the side of a square vessel that contains a malt bushel per inch of depth.; The slide has two identical C scales, logarithmically divided from 1 to 10. The back of the slide has a table of divisors for converting between volumes in cubic inches and numbers of gallons for substances in square or circular containers. The numbers in this table are squares of the gauge points in the table on the back of the slide on side II. Underneath the slide is marked: Will^m. Wright : April. 30. 1795.; According to Gloria Clifton, the firm of Lewis & Briggs operated in London from at least 1795 to 1799. The Smithsonian acquired this object in 1961.; References: Colin Barnes, "The Customs and Excise Gauging Slide Rule," Journal of the Oughtred Society 4, no. 2 (1995): 53–57; Ron Manley, "Gauging," http://www.sliderules.info/a-to-z/gauging.htm; Gloria Clifton, Directory of British Scientific Instrument Makers (London: National Maritime Museum, 1995), 167.
Location: Currently not on view

date made: 1795

maker: Lewis & Briggs

ID Number: MA.319510
catalog number: 319510
accession number: 239015

The arms of this small brass instrument have straight ends. One side has a double scale of chords that runs from 10 to 90. The outer edge on one arm has a scale that runs from 4 to 24 and is labeled poids des boulets.

Description: The arms of this small brass instrument have straight ends. One side has a double scale of chords that runs from 10 to 90. The outer edge on one arm has a scale that runs from 4 to 24 and is labeled poids des boulets. The inner edge of both arms has a double scale for the specific weights of four metals, marked with their symbols. The sector is marked: Butterfield (/) AParis. The hinge is decorated with a flower.; On the other side, the outer edge of one arm has a scale that runs from 4 to 24 and is labeled Calibre des pieces. Both arms have double scales of equal parts, running from 10 to 120, and for inscribed regular polygons, from 12 sides to three sides. Compare to MA.321677 and 1985.0580.04.; Michael Butterfield (1635–1724) was an English instrument maker who worked in France from around 1677 until his death. He was best known for his distinctive sundials.; References: Maya Hambly, Drawing Instruments, 1580–1980 (London: Sotheby's Publications, 1988), 24, 134–135; Adler Planetarium, Webster Signature Database, http://historydb.adlerplanetarium.org/signatures/; Henri Michel, Scientific Instruments in Art and History, trans. R. E. W. Maddison and Francis R. Maddison (Barrie and Rockliff, 1967), 206.
Location: Currently not on view

date made: ca 1700

maker: Butterfield, Michael

ID Number: MA.321676
catalog number: 321676
accession number: 245711

This large brass instrument has two rectangular arms with flat ends and an undecorated hinge.

Description: This large brass instrument has two rectangular arms with flat ends and an undecorated hinge. On one side and from the top down, each arm has a sine scale, running from 10 to 90 degrees; a tangent scale, running from 45 to 75 degrees; and a second tangent scale, running from 10 to 45 degrees. The top arm has a scale labeled "Rum." that runs from 1 to 8, and the lower arm has a scale labeled "Lon." that runs from 60 to 10. Spanning both arms on the outer edge are four scales: log tangents, running from 1 to 45 degrees; log sines, running from 1 to 90 degrees; log versed sines, running from 165 to 10 degrees; and logarithmic, labeled "Num." and running from 1 to 10 twice. The front is marked: Tho^s. Harris & Son (/) British Museum London.; The other side has a double scale along the fold line for regular polygons, from 12 to 4 sides. Each arm has a "line of lines" scale, running from 1 to 10; a secant scale, running from 10 to 75; and a scale of chords, running from 10 to 60. The upper arm has a scale of equal parts, running from 90 to 10, and scales for the inclined meridian, chords, and sines, each running from 10 to 90. The lower arm has scales for tangents, running from 10 to 45; latitude, running from 10 to 90; hours, running from I to VI; and chords, running from 0 to 180. Spanning both arms along the outer edge is a scale of inches, running from 24 to 1 and divided to twentieths of an inch.; The London telescope maker Thomas Harris (about 1750–1827) took his son, William, as a partner in 1806. By 1817, the firm was located on Great Russell Street, across from the entrance to the British Museum, and presented itself as "opticians to the Royal Family." In 1846, the workshop moved to High Holburn Street; it remained in business until the 20th century.; References: Gloria Clifton, Directory of British Scientific Instrument Makers 1550–1851 (London: National Maritime Museum, 1995), 125–126; Adler Planetarium, Webster Signature Database, http://historydb.adlerplanetarium.org/signatures/.
Location: Currently not on view

date made: 1806-1846

maker: Thomas Harris & Son

ID Number: MA.316747
catalog number: 316747
accession number: 227807

In 1614 Scottish mathematician John Napier announced his discovery of logarithms.

Description: In 1614 Scottish mathematician John Napier announced his discovery of logarithms. Within eight years, Edmund Gunter, an English clergyman who was interested in mathematics, had devised a scale on which logarithms could be multiplied and divided, by measuring the distance between two logarithmic numbers with a pair of dividers. Shortly thereafter, instrument makers were manufacturing wooden rules with standard (or "natural") scales typically used in navigation on one side and Gunter's logarithmic (or "artificial") scales on the other side.; This instrument, a precursor of the slide rule, became known as Gunter's scale. Since it was made of one piece of wood, the expansion and shrinking that happened at sea did not impede its operation. Thus, Gunter's scale remained popular with ship's navigators until the end of the 19th century, when new materials were available for the manufacture of slide rules. Surveyors, mechanics, craftsmen, and retailers also used Gunter's scales to make logarithmic and trigonometric calculations.; This 2' boxwood rule is identical to 319077 and 333945. The top of one side has a scale of inches, divided to tenths of an inch and numbered by ones from 23 to 1. On the left are 10" and 9" (divided to 1/2") plotting scales with diagonal scales at each end. In the middle are scales for rhumbs, chords, sines, tangents, and semitangents. On the right are scales for leagues, rhumbs, miles of longitude, and chords. Brass pins at the zero and 60° marks reduce wear from the points of dividers, which were used to transfer measurements between the scale and the user's drawing.; The other side has logarithmic scales: sines of rhumbs, tangents of rhumbs, line of numbers, sines of degrees, versines of degrees, and tangent of degrees. At the bottom edge are a meridional line and a scale of equal parts that divides 23" into 17 sections. The sections are numbered by tens from 60 to 10 and from 100 to 0.; On the side with the scale of inches, the rule is marked in the lower right corner: MERRIFIELD & C^O (/) NEW-YORK. Merrifield & Co. sold Gunter's scales in Boston and New York in the early 19th century.; References: Adler Planetarium, Webster Signature Database, http://historydb.adlerplanetarium.org/signatures/; Otto van Poelje, "Gunter Rules in Navigation," Journal of the Oughtred Society 13, no. 1 (2004): 11–22; George Curtis, A Treatise on Gunter's Scale, and the Sliding Rule (Whitehall, N.Y., 1824); Florian Cajori, "On the History of Gunter's Scale and the Slide Rule During the Seventeenth Century," University of California Publications in Mathematics 1, no. 9 (February 17, 1920): 187–209.
Location: Currently not on view

date made: ca 1825

retailer: Merrifield & Co.
maker: Merrifield & Co.

ID Number: MA.318174
catalog number: 318174
accession number: 232132

This green hardcover instruction manual, lifetime guarantee certificate, and leaflet on "How to Take Care of Your Slide Rule" were received with MA.333923. The citation information for the manual is: Michael P.

Description: This green hardcover instruction manual, lifetime guarantee certificate, and leaflet on "How to Take Care of Your Slide Rule" were received with MA.333923. The citation information for the manual is: Michael P. Smyth, Analon Engineering – Science Analysis Slide Rule Instruction Manual (New York: Keuffel & Esser, 1967). A scan is found at "Keuffel & Esser, Specialty Slide Rules," International Slide Rule Museum, http://sliderulemuseum.com/KE_Specialty.htm. Smyth taught electrical engineering at the University of Pennsylvania. The manual describes the Analon slide rule; defines dimensions, units, and dimensional analysis; suggests applications; and provides practice problems.; The certificate has model number S22-4. The model number for the leaflet about caring for a K&E slide rule is S14-5. The leaflet is small (4 X 3 inches) and was copyrighted in 1944, 1949, 1958, and 1962. Users were to clean the slide rule only with a moistened cloth. Instructions are provided for adjusting and aligning the slide rule.
Location: Currently not on view

date made: 1967

author: Smyth, Michael P.
publisher: Keuffel & Esser Co.

ID Number: MA.304347.02
accession number: 304347
catalog number: 304347.02

This sixteen-inch one-sided wooden slide rule has scales labeled A and D on the base. There are scales labeled B and C on one side of the slide, with S, L, and T scales on the other side.

Description: This sixteen-inch one-sided wooden slide rule has scales labeled A and D on the base. There are scales labeled B and C on one side of the slide, with S, L, and T scales on the other side. The A and B scales are divided logarithmically from 1 to 10 twice; the C and D scales are divided logarithmically from 1 to 10 once. The S scale runs from 0 to 80 degrees, and the T scale from 0 to 45 degrees. The L scale is divided logarithmically from 0 to 10. A scale of 40 centimeters is divided to millimeters on the front edge. A scale of 16 inches divided to 1/16-inch is on the other, beveled edge. The scales are all on white celluloid. A table of numerical ratios and equivalences is attached to the back of the rule. A frameless glass indicator was received with the instrument and noted during cataloguing around 1965, but it is no longer present.; The top of the base is marked in red: PAT. JUNE 5, 1900; KEUFFEL & ESSER CO. N.Y.; MADE IN U.S.A. The right end of the slide is marked in red: < 4045 >. The left end of the back of the slide and the left end of the centimeter scale on the base are both marked with a serial number: 46538. The file for the instrument records that the indicator was marked with a patent date of 8.17.15. Compare to MA.322761 and 1987.0634.01.; Keuffel & Esser first advertised the model 4045 Mannheim slide rule in 1906 and stopped selling it between 1936 and 1939. The date on the indicator suggests that this example was made after mid-1915. If the accession file is correct, the rule was given to the Smithsonian by the U.S. Army Signal Corps in 1923. However, the presence of a serial number and the lettering of the A, B, C, and D scales suggest a somewhat later date. (K&E began to assign serial numbers in 1923, and a serial number of 46538 indicates a date around 1925.) Additionally, the accession file records that the slide rule had the Signal Corps type number ML–40. According to the 1920 Storage Catalogue for the Corps, an ML–40 slide rule was a ten-inch polyphase duplex slide rule, graduated on both sides with a frameless glass indicator, specifically "Keuffel & Esser Co.'s No. 4088-3, or equal." Thus, it is possible that this example is not the slide rule received with the 1923 accession. There are no known discrepancies in the files for MA.318480 and MA.321778, the K&E model 4088-3 slide rules acquired by the Smithsonian before 1965, though.; References: Wayne E. Feely, "K & E Slide Rules," The Chronicle of the Early American Industries Association 49, no. 5 (June 1996): 50–52, on 51; Ed Chamberlain, "Estimating K&E Slide Rule Dates," 27 December 2000, http://www.sphere.bc.ca/test/ke/320-k+e_date2.jpg; Signal Corps, Storage Catalogue (Washington, D.C.: Government Printing Office, 1920), 29, 575.
Location: Currently not on view

date made: ca 1925

maker: Keuffel & Esser Co.

ID Number: MA.308201
accession number: 70852
catalog number: 308201

This ivory instrument has two rectangular arms with flat edges and a circular brass hinge. The scales run from top to bottom on each arm, unlike the paired double scales on Italian and French sectors.

Description: This ivory instrument has two rectangular arms with flat edges and a circular brass hinge. The scales run from top to bottom on each arm, unlike the paired double scales on Italian and French sectors. On one side, each arm has a sine scale, running from 10 to 90 degrees; a tangent scale, running from 45 to 75 degrees; and a second tangent scale, running from 10 to 45 degrees. Spanning both arms on the outer edge are three scales: log sine, running from 2 to 70 degrees; log tangent, running from 1 to 45 degrees; and logarithmic, running from 1 to 10 twice and then from 10 to 20. The top face of the instrument has a scale of equal parts that runs from 100 to 10. The front is marked: *Gilkerson* (/) Tower-Hill-London.; The other side has a double scale along the fold line for regular polygons, labeled POL and running from 12 to 4 sides. Each arm has a scale of equal parts, running from 1 to 10 and labeled L; a secant scale, running from 20 to 75 and labeled s; and a scale of chords, running from 10 to 60 and labeled C. The upper arm has scales labeled Im and Ch that each run from 10 to 90. The lower arm has scales labeled La, running from 10 to 70; and H, running from I to VI. These four scales (inclinations of meridians, chords, latitudes, and hours) are associated with making sundials. Spanning both arms on the outer edge is a scale of inches, running from 11 to 1 and divided to tenths of an inch.; James Gilkerson was in business in Tower Hill, London, from 1809 to 1825. Donor Ada B. Richey reported that her husband's ancestor, Lt. Col. Alexander Matheson (b. 1788), was the original owner of this drawing instrument. He settled in Perth, Canada, after serving in the British army during the War of 1812.; References: Gloria Clifton, Directory of British Scientific Instrument Makers 1550–1851 (London: National Maritime Museum, 1995), 113; J. F. Heather, Mathematical Instruments: Their Construction, Adjustment, Testing, and Use, rev. ed. (London: Crosby Lockwood and Co., 1870), i:42–52; Samuel Sturmy, "The Art of Dialling," The Mariner's Magazine (London, 1669).
Location: Currently not on view

date made: 1809-1825

maker: Gilkerson, James

ID Number: MA.321756
accession number: 243754
catalog number: 321756

The brass core of this cylindrical slide rule is covered with paper marked with forty A scales. The core fits in an open rotating frame that holds twenty metal slats; each slat is lined with cloth, covered with paper, and marked with two B and two C scales.

Description: The brass core of this cylindrical slide rule is covered with paper marked with forty A scales. The core fits in an open rotating frame that holds twenty metal slats; each slat is lined with cloth, covered with paper, and marked with two B and two C scales. Wooden knobs on each end of the core rotate the instrument. The frame is attached to a mahogany base.; The first A scale runs from 100 to 112; the fortieth runs from 946 to 100 to 105. The first B scale runs from 100 to 112, the last from 946 to 100 to 105. The first C scale runs from 100 to 334, the last from 308 to 305. The paper covering the core is also printed in italics on the right side: Made by Keuffel & Esser Co., New York; Patented by Edwin Thatcher [sic], C.E. Nov. 1st., 1881.; A paper of instructions and rules for operating THACHER'S CALCULATING INSTRUMENT is glued to the top front of the base. The top back of the base is stamped: KEUFFEL & ESSER CO. (encircling N.Y.); 4012 (/) 4917; TRADEMARK (below the K&E logo of a lion).; The instrument is stored in a mahogany rectangular case. A square off-white label inside the lid is printed: KEUFFEL & ESSER CO. (/) NEW YORK HOBOKEN, N.J. (/) CHICAGO ST. LOUIS SAN FRANCISCO MONTREAL (/) DRAWING MATERIALS, SURVEYING INSTRUMENTS (/) MEASURING TAPES (/) No. 4012 (/) SERIAL 4917.; Keuffel & Esser sold versions of the Thacher cylindrical slide rule from about 1883 until about 1950. There were two models, one with a magnifying glass (K&E model 1741 before 1900, K&E model 4013 after) and one without (K&E model 1740 before 1900, K&E model 4012 after). This is a model 4012; the serial number suggests it was manufactured around 1920. Model 4012 sold for $35.00 in 1916, $60.00 in 1922, and $70.00 in 1927.; The National Bureau of Standards (now the National Institute of Standards and Technology) declared this object excess property and transferred it to the Smithsonian in 1965. In 1968, the Department of Commerce borrowed the slide rule to exhibit in the U.S. Pavilion at HemisFair, an international exposition held in San Antonio, Tex. According to the accession file, a staffer replaced four missing screws on the base before returning the rule.; See also MA.312866; MA.323504; and MA.322730.; References: Wayne E. Feely, "Thacher Cylindrical Slide Rules," The Chronicle of the Early American Industries Association 50 (1997): 125–127; Keuffel & Esser Co., Slide Rules and Calculating Instruments (New York, 1916), 22; Keuffel & Esser Co., Slide Rules and Calculating Instruments (New York, 1922), 21; Keuffel & Esser Co., Slide Rules and Calculating Instruments (New York, 1927), 20.
Location: Currently not on view

date made: ca 1920

maker: Keuffel & Esser Co.

ID Number: MA.326628
accession number: 261654
maker number: 4917
catalog number: 326628

These two 2' boxwood rules are identical to each other and to MA.319077 and MA.318174. The top of one side has a scale of inches, divided to tenths of an inch and numbered by ones from 23 to 1.

Description: These two 2' boxwood rules are identical to each other and to MA.319077 and MA.318174. The top of one side has a scale of inches, divided to tenths of an inch and numbered by ones from 23 to 1. On the left are 10" and 9" (divided to 1/2") plotting scales with diagonal scales at each end. In the middle are scales for rhumbs, chords, sines, tangents, and semi-tangents. On the right are scales for leagues, rhumbs, miles of longitude, and chords. Brass pins at the zero and 60° marks reduce wear from the points of dividers, which were used to transfer measurements between the scale and the user's drawing.; The other side has logarithmic scales: sines of rhumbs, tangents of rhumbs, line of numbers, sines of degrees, versines of degrees, and tangent of degrees. At the bottom edge are a meridional line and a scale of equal parts that divides 23" into 17 sections. The sections are numbered by tens from 60 to 10 and from 100 to 0.; The first rule is marked on the first side in the lower right corner: BELCHER BRO^S. & C^o. NEW – YORK. Thomas Belcher began making rules in New York in 1821 and was joined by his brother, William, in 1825. Around 1831 another brother, Charles, joined the firm, and the company's name was changed from T. & W. Belcher to Belcher Brothers. Around 1843 manufacturing of rules moved to New Jersey and the firm went by the name Belcher & Bros. Around 1853 some of the men's sons joined the firm, and the name was changed to Belcher Bros. & Co. The first rule dates to this period. The company had become the largest American manufacturer of rules, but it was surpassed by Stanley in the second half of the 19th century. Belcher stopped manufacturing rules around 1877.; The second rule is unmarked. Key points around the scales are marked with suns, unlike the asterisks on the first rule; the abbreviations for the scale labels are different; and the bottom edge is beveled at a sharper angle than the bottom edge of the first rule. These differences indicate that the second rule was manufactured by a different firm. This rule also has pencil marks on the top and bottom edges.; References: Otto van Poelje, "Gunter Rules in Navigation," Journal of the Oughtred Society 13, no. 1 (2004): 11–22; Belcher Bros. & Co.'s Price List of Boxwood & Ivory Rules (New York, 1860; reprint, Fitzwilliam, N.H.: Ken Roberts Publishing Co., 1982); Philip A. Cannon II, "The Makers and Markers of Gauges, Rules, Squares, and Tapes," http://www.pactu.com/makers.htm.
Location: Currently not on view

date made: ca 1853–1877

maker: Belcher Brothers

ID Number: MA.333945
accession number: 296611
catalog number: 333945

This sixteen-inch instrument has a wooden core coated with white celluloid. There are A and D scales on the base, with B and C scales on one side of the slide; the scales are not labeled with letters.

Description: This sixteen-inch instrument has a wooden core coated with white celluloid. There are A and D scales on the base, with B and C scales on one side of the slide; the scales are not labeled with letters. The reverse of the slide has S, T, and L scales, which are labeled with these letters. The top edge is beveled and has a scale of inches, divided to sixteenths of an inch. The front edge has a scale of centimeters, divided to millimeters. A table of numerical ratios and equivalences is pasted to the back of the rule. A glass "frameless" indicator has plastic edges.; The base is marked in red: KEUFFEL & ESSER CO. N.Y.; PAT. JUNE 5, 1900. K&E head of manufacturing Willie L. E. Keuffel received this patent for a method of adjusting a slide rule, accomplished with four screws on the back of the instrument. The left end of the slide is marked in red: < 4045 >. K&E first advertised model 4045 in 1906. The edge of the indicator is marked: K&E.CO.N.Y. (/) PAT.8.17.15. Keuffel also took out this patent, for the design of the frameless indicator. Since the plastic on the indicator is the same color as the rule and thus probably original to the instrument, this example was likely made after 1915. The indicator was changed again in 1936, and K&E no longer made this model by 1939.; The rule is in a cardboard box faced with dark brown leather. The box is marked: KEUFFEL & ESSER Co. (/) MANNHEIM (/) SLIDE RULE. The instrument was found in a Smithsonian storage court and catalogued in 1963. The indicator was broken in 2005 and is now stored in a separate bag. Compare this example to 1987.0634.01 and MA.308201.; References: Willie L. E. Keuffel, "Slide-Rule" (U.S. Patent 651,142 issued June 5, 1900); Willie L. E. Keuffel, "Slide-Rule Runner" (U.S. Patent 1,150,771 issued August 17, 1915); Wayne E. Feely, "K & E Slide Rules," The Chronicle of the Early American Industries Association 49, no. 5 (June 1996): 50–52; Clark McCoy, "Collection of Pages from K&E Catalogs for the 4041 Family," http://www.mccoys-kecatalogs.com/KEModels/ke4041family.htm; Catalogue of Keuffel & Esser Co., 32th ed. (New York, 1906), 322; Catalogue of Keuffel & Esser Co., 35th ed. (New York, 1915), 299; Catalogue of Keuffel & Esser Co., 38th ed. (New York, 1936), 311.
Location: Currently not on view

date made: 1915-1936

maker: Keuffel & Esser Co.

ID Number: MA.322761
accession number: 251560
catalog number: 322761

This five-inch, one-sided cardboard linear slide rule has a metal cursor in the double-chisel style. (Compare to MA.318477 and 1977.0370.01.) There are A and D scales on the base and B and C scales on the slide. The A and B scales are divided logarithmically from 1 to 10 twice.

Description: This five-inch, one-sided cardboard linear slide rule has a metal cursor in the double-chisel style. (Compare to MA.318477 and 1977.0370.01.) There are A and D scales on the base and B and C scales on the slide. The A and B scales are divided logarithmically from 1 to 10 twice. The C and D scales are divided logarithmically from 1 to 10 once. A figure holding a club is shown in the lower left corner. A dark brown case of coated paper is included.; The figure on the slide rule was used by Gebr. Wichmann (Wichmann Brothers) in Berlin, a company founded in 1873. In materials, size, and scales, this instrument closely resembles model 466, shown in the 1910 catalog. However, the illustration in the catalog indicates that the maker's name, place of manufacture, model number, and price are printed on the front of the rule. This instrument does not have these marks, so it may have been made before 1910. The No. 466 slide rule sold for 0.75 marks and was one of the least expensive slide rules listed in the catalog. (Only model 469, with a C scale that began at pi, sold for the same price.); This instrument is signed on the back: W. F. Meggers. William F. Meggers (1888–1966) was a spectroscopist long associated with the U.S. National Bureau of Standards. He received his B.A. in physics from Ripon College in 1910, his M.A. in physics from the University of Wisconsin in 1916, and his Ph.D. in physics, mathematics, and astronomy from Johns Hopkins University in 1917. If he used this rule, it seems likely that he acquired it as a student. For a slide rule apparently acquired by Meggers in 1907 that was considerably more precise and more costly, see MA.335270.; References: Gebr. Wichmann, Anleitung zum Gebrauch des Rechenstabes (Berlin, 1910), 21; "Dr. Meggers Dies at 78," The NBS Standard 11, no. 9 (December 1966): 2–3.
Location: Currently not on view

date made: before 1910

maker: Gebr. Wichmann

ID Number: MA.293320.2820
accession number: 293320
catalog number: 293320.2820

This one-sided, ten-inch wooden rule has a layer of yellowed white celluloid on the front side. It has unlettered A and D scales on the base and B and C scales on one side of the slide. The other side of the slide has S, L, and T scales. The indicator is glass in a metal frame.

Description: This one-sided, ten-inch wooden rule has a layer of yellowed white celluloid on the front side. It has unlettered A and D scales on the base and B and C scales on one side of the slide. The other side of the slide has S, L, and T scales. The indicator is glass in a metal frame. The top edge is beveled and has a 25-centimeter scale, divided to millimeters. A second scale, 26 centimeters in length, is on the front edge. Underneath the slide is a third centimeter scale, numbered from 27 to 51.; The bottom of the base is marked in gold: A. W. FABER. Tables of equivalent measures and lists of constants (in German) are printed on paper glued to the back of the instrument. The rule is in a cardboard case covered with black leather, which is in excellent condition. The case is marked: Rechenstab (/) von (/) A. W. Faber. The back of the case is signed illegibly in pencil.; A. W. Faber began manufacturing wooden slide rules in 1882 and added celluloid facings in 1887. From about 1888 to 1900, the rules were often marked not only "A. W. FABER" but "Made in Germany." The metal indicator with a glass window was introduced in 1889. Although there is no model number on this rule, in the 1910s this combination of scales and indicator was sold as model 360. See MA.304722.02 for a later version of this rule, which mentions an 1899 patent and has a digit registering indicator introduced in 1905.; Reference: Dieter von Jezierski, Slide Rules: A Journey Through Three Centuries, trans. Rodger Shepherd (Mendham, N.J.: Astragal Press, 2000), 54, 90; Trevor Catlow, "Suggestions for Dating pre-1920 Faber Castell Slide Rules," Journal of the Oughtred Society 18, no. 2 (2009): 46–53; "Time Line for A. W. Faber and Faber-Castell," http://sliderulemuseum.com/SR_Dates.htm#Faber.
Location: Currently not on view

date made: about 1890

maker: Faber, A. W.

ID Number: MA.314793
catalog number: 314793
accession number: 210147

From the late 18th to the mid-19th centuries, British engineers began to use slide rules. This ivory and silver instrument is a four-fold engineer's rule that unfolds to a length of 24 inches.

Description: From the late 18th to the mid-19th centuries, British engineers began to use slide rules. This ivory and silver instrument is a four-fold engineer's rule that unfolds to a length of 24 inches. On half of one side is a slide rule with A and D scales on the base and B and C scales on the slide. The A and D scales seem to run continuously, although the slide only moves on the second six inches of the rule.; The words IRON and ROPE appear several times along the edge of the A scale. Along the edge of the D scale is marked: DESCRIPTION SQUARE CYL[I]ND[ER] GLOBE SQUARE CYL[I]ND[ER] WEIGHT STRAIN WORK INCLIN[E] POLYGON SIDE GOVERNORS H[ORSE]P[OWER] ENGIN[E]S STE[A]M TEM[PERATURE]. When the rule is folded, these markings correspond to the tables on the other half of the instrument.; The other half of this side has a table of gauge points for the A scale. Instructions printed on the rule suggest that calculations on the slide rule were intended to be made with calipers. Additional tables and instructions for working with ropes and chains are on this half, which is marked: IMPROVED & ARRANG[E]D (/) BY R^T HAWTHORN (/) CIVIL ENGINEER (/) NEWCASTLE TYNE.; The other side has a scale of 24 inches divided to eighths of an inch along the edge. The metal joint has a protractor divided in increments of 5 degrees and marked by tens from 0 to 180. When the instrument is folded around the joint, there are tables for the extreme strain possible in bars and beams of various substances and for equivalent measures. The joint is marked: G. R. STEPHENSON (/) ENGINEER (/) Adam Pensom.; In 1832 civil engineer Robert Hawthorn (1796–1867) designed a new form of slide rule for manufacturing locomotives and other engines. In 1859 dealers sold the rule for 5 shillings and 6 pence. The names on the joint may refer to the British civil engineer George Robert Stephenson (1819–1905), nephew to the engineer George Stephenson (1781–1848), who sought mechanical advice from Hawthorn's father, and to Adam Pensom (b. 1824), who was a retired gas engineer living in London, according to the 1881 British census. The Smithsonian acquired this object in 1973.; References: Robert Hawthorn, Instructions for the Use of the Mechanics' Sliding Rule (Newcastle-upon-Tyne, 1841), available online at http://www.physics.uq.edu.au/physics_museum/hawthorne/; "Mr. Robert Hawthorn," Minutes of the Proceedings of the Institution of Civil Engineers 27 (1867–1868): 590–592; advertisement by John Archbutt, The Mechanics' Magazine, n.s., 1, no. 10 (March 4, 1859): 486; Peter M. Hopp, Joint Slide Rules (Jeremy Mills Publishing: Lindley, Huddersfield, West Yorkshire, 2009).
Location: Currently not on view

date made: after 1832

maker: Hawthorn, Robert

ID Number: MA.306697.01
accession number: 306697
catalog number: 306697.01

This flyer, printed in blue ink on white paper, is titled: Simplify any Calculation with an Otis King. The text identifies potential users and describes the functions of this cylindrical slide rule.

Description: This flyer, printed in blue ink on white paper, is titled: Simplify any Calculation with an Otis King. The text identifies potential users and describes the functions of this cylindrical slide rule. The back of the flyer lists six sample problems the Otis King Pocket Calculator could solve. It is stamped with the address of an English dealer of scientific instruments: H. T. POCKETT. (/) 25. NELSON ROAD. (/) GREENWICH. S.E.10. The price is listed as 47s. 6d. postpaid.; The flyer arrived with 1987.0788.01 and probably dates to the same period, from about 1960 to 1962. See also 1987.0788.06.
Location: Currently not on view

date made: ca 1960-1962

maker: Carbic Limited

ID Number: 1987.0788.07
accession number: 1987.0788
catalog number: 1987.0788.07

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