Engineering, Building, and Architecture

• 

  Japanese L-Square

  Description

  In 1876 the Japanese Empire Department of Education exhibited many instruments at the Centennial International Exhibition, a World’s Fair held in Philadelphia. After the exhibition, John Eaton, the U.S. Commissioner of Education, arranged for the transfer of Japan's entire exhibit—including this object—to the Bureau of Education (then part of the Department of the Interior) for a planned museum. The museum closed in 1906, and much of the collection was transferred to the Smithsonian in 1910.

  On one side, this 18-1/2" L-shaped brass instrument is divided along the outside of its short leg into 7.5 units of 1-3/16" (3 cm). Each unit is thus roughly equivalent to the sun, a traditional Japanese unit of length that is 1/10 of a shaku, a "foot" measure. The units are subdivided into 10 parts. The fifth unit is marked with an arrangement of five dots.

  The outer edge of the long leg is divided into ten units of 1-3/4" (4.3 cm). Each unit is subdivided into tenths. From the right, the fifth and tenth units are marked with an arrangement of five dots. The other units are marked with single dots. A single dot also marks the 0.9 points. Groups of three dots mark the 3.55 and 7.05 points, and another group of three dots marks a point to the left of the divisions on the scale.

  The inner edge of the long leg is divided from left to right into five units of 1-13/16" (4.5 cm) and five sun. The larger units are marked with Japanese characters. The sun are subdivided into tenths and marked with single dots, except for the fifth unit, which is marked with five dots.

  On the other side, the outer edges of both legs are divided into sun subdivided into tenths. The midpoint of each unit is marked with three dots. The fifth, tenth, and fifteenth units from the vertex are marked with five dots. The instrument was designed for measuring lengths, drawing right angles, and determining whether two lines are perpendicular to one another.

  Other educational mathematical objects exhibited by Japan in 1876 include MA.261283, MA.261284, MA.261285, MA.261286, MA.261287, MA.261289, MA.261291, MA.261292, MA.261293, MA.261294, MA.261298, MA.261299, MA.261301, MA.261302, MA.261305, MA.261306, and MA.261313.

  References: Japan. Department of Education, An Outline History of Japanese Education: Prepared for the Philadelphia International Exhibition, 1876 (New York: D. Appleton, 1876), 121–122, 191–202; U.S. Centennial Commission, International Exhibition, 1876. Reports and Awards, ed. Francis A. Walker (Washington, D.C.: Government Printing Office, 1880), viii:143, 335; U.S. Bureau of Education, Annual Report of the Commissioner (1876), ccxi–ccxii.

  Location

  Currently not on view

  date made

  before 1876

  ID Number

  MA.261295

  accession number

  51116

  catalog number

  261295

  Data Source

  National Museum of American History

• 

  Instruction Card for Robertson-Amsler Polar Planimeter

  Description

  These salmon-colored card fragments were received with MA.333766. They give partial instructions for taking measurements with an "averaging planimeter." The reverse side of the card has a drawing of a connector for a steam engine indicator and several user testimonials.

  Location

  Currently not on view

  date made

  ca 1900

  maker

  James L. Robertson & Sons

  ID Number

  MA.302380.02

  accession number

  302380

  catalog number

  302380.01

  Data Source

  National Museum of American History

• 

  Peaucellier Inversor, Kinematic Model by Martin Schilling, series 24, model 10, number 349

  Description

  Around 1900, American mathematicians introduced ideas to their students using physical models like this one. This model is the tenth in a series of kinematic models sold by the German firm of Schilling to show a mechanical method for generating mathematical curves.

  Linkages are joined rods that move freely about pivot points. A pair of fireplace pincers is an example of a very simple linkage. Producing straight line motion was an important component of many machines. But producing true linear motion is very difficult. One area of research during the 19th century was to use linkages to produce linear motion from circular motion. In this context “inverse” is a geometric term that refers to the process of using algebra and trigonometry to convert or invert one geometric shape into another. In this case, the inverse of the circle will be a straight line. So an “inversor" is a device that finds the inverse of a geometrical object: the conversion of a circle to a straight line in the case of this model.

  In 1864 French engineer Charles Nicolas Peaucellier (1832-1913) created a seven-bar linkage which succeeded in producing pure linear motion. Since then, such seven-bar linkages are often referred to as “Peaucellier cells” or a “Peaucellier’s inversor.” His discovery was the first solution of what was referred to as the problem of parallel motion: converting rotational to linear motion using only “rods, joints and pins.”

  This linkage is constructed of seven metal armatures (two longer arms of 15 cm, four shorter arms of 5 cm) hinged so as to create a kite shape with a rhombus (diamond) shape at the top of the kite. This horizontal assembly is then attached to a central vertical axis that is rotated by turning a crank below the baseplate. Fingerholds are attached to the two primary hinge points to allow the linkage to be articulated from above. Below these fingerholds are metal points used to trace the motion of the linkage on the paper.

  The bottom (tail end) of the kite is fixed on a circle. As the dial is turned or the fingerholds are moved, the point internal to the linkage traces the circle, resulting in the point at the top of the kite tracing a straight line. The seven-bar linkage works by keeping one end of the linkage (the tail end of the kite) fixed on a circle. As the center point traces around the circle, the point at the opposite end of the linkage (the top of the kite) traces a straight line. The German title for this model is: Inversor von Peaucellier 1864.

  This model is marked Halle a.S., but this is lined through and has a Leipzig stamp. In or after 1903 Schilling moved the business from Halle to Leipzig. On top of the mounting plate is an aged paper sheet showing the name and maker of the linkage. Printed on the paper are a black circle and a red circle to show the circular path; a red curve; and, what was most likely a black linear path, but which is now worn through the paper with use.

  References:

  Johnson, Wm. Woolsey, “The Peauceller Machine and Other Linkages,” The Analyst, Vol 2, No. 2, Mar 1875, pp. 41-45.

  Roberts, David Lindsay, “Linkages, A Peculiar Fascination” in Tools of American Mathematics Teaching, 1800-2000, Kidwell, P. A. et.al., Johns Hopkins University Press, 2008, pp. 233-242.

  Schilling, Martin, Catalog Mathematischer Modelle für den höheren mathatischen Unterricht, Halle a.S., Germany, 1911, pp. 56-57. Series 24, group IV, model 10.

  Mathematics and interactive Java applet can be found at http://www.cut-the-knot.org/pythagoras/invert.html\

  Location

  Currently not on view

  date made

  ca 1900

  maker

  Schilling, Martin

  ID Number

  MA.304722.21

  catalog number

  304722.21

  accession number

  304722

  Data Source

  National Museum of American History

• 

  Protractor Retailed by Benjamin Pike & Son

  Description

  This brass circular protractor was manufactured in the mid-19th century and made available for sale by the New York City firm headed by Benjamin Pike (1777–1863). Pike, a dealer of optical, mathematical, and philosophical instruments whose firm serviced the entire United States, partnered at various times with his sons, Benjamin Jr., Daniel, and Gardner. The business was called “Benjamin Pike & Son,” as is marked on the vernier limb of this protractor, between 1831 and 1841 and between 1843 and 1850.

  This protractor likely would have been of interest to surveyors and engineers. The object is divided by single degrees. It bears two sets of markings by tens in the clockwise direction: from 0° to 90° to 0° to 90° to 0°, and from 10° to 360°. Brass arms extend into the center to divide the protractor into quadrants. The arms are not placed at the 0° and 90° points, as one might expect, but rather at the 50/50, 40/140, 50/230, and 40/320 markings. There are rounded, beveled notches at the 90/90 and 90/270 markings. A round hole (5/8" diameter) is at the center. Crosshairs would typically have been placed in this hole to mark the origin point for measuring angles, but no crosshairs are present. Instead, a brass piece fills about one-third of the hole.

  An arm pivoted from the center carries a vernier, which allows the user to read off angles to 10 minutes of arc. The vernier is marked by 30s from 60 to 0 to 60. The vernier arm is marked: Benj-n Pike & Son New York. The arm extends beyond the vernier. A brass strip, fastened on top of the arm, contains a sharp metal pin that pokes through a hole near the end of the arm. The pin was used to prick, or mark, angle points.

  This protractor has some notable differences from the circular protractor depicted in Pike catalogs of 1848 and 1856: its outer edge is smooth instead of appearing to bear gear teeth; it has one vernier arm instead of two; and it has two sets of markings instead of one.

  References: Deborah J. Warner, “Browse by Maker: Pike,” National Museum of American History Physical Sciences Collection: Surveying and Geodesy, http://americanhistory.si.edu/collections/surveying/maker.cfm?makerid=22; Benjamin Pike Jr., Pike’s Illustrated Descriptive Catalogue of Optical, Mathematical, and Philosophical Instruments (New York, 1848), 43–45; Benjamin Pike Jr., Pike’s Illustrated Descriptive Catalogue of Optical, Mathematical, and Philosophical Instruments (New York, 1856), 43–45; facsimile with historical introduction by Deborah J. Warner (Dracut, Mass., and San Francisco, 1984).

  Location

  Currently not on view

  date made

  1831-1850

  maker

  Pike, Jr., Benjamin

  ID Number

  MA.304826.059

  accession number

  304826

  catalog number

  304826.059

  Data Source

  National Museum of American History

• 

  Keuffel & Esser 1740 Thacher Cylindrical Slide Rule

  Description

  In 1881, Edwin Thacher, a "computing engineer" for the Keystone Bridge Company in Pittsburgh, Pennsylvania, received a patent for an improvement in slide rules. Thacher was a graduate of Rennselaer Polytechnic Institute who spent much of his career designing railway bridges. To assist in his calculations, he designed a cylindrical slide rule. Thacher's rule, though it fit on a desk, was equivalent to a conventional slide rule over 59 feet long. It had scales for multiplication and division and another scale, with divisions twice as large, for use in finding squares and square roots. But it had no trigonometric scales.

  To produce his "calculating instrument," Thacher turned to the London firm of W. F. Stanley. The company even designed a special dividing engine for preparing the scales for the instrument. These were printed on paper sheets, which were pasted to the drum and the slats. In this example, the paper is also printed in italics on the right side: Patented by Edwin Thatcher [sic], C.E. Nov. 1st 1881. Divided by W. F. Stanley, London, 1882.

  The drum is rotated with wooden handles. The cylinder of slats is held in place with a brass frame, which is affixed to a wooden base. A paper of DIRECTIONS AND RULES FOR OPERATING is lacquered to the front of the base. The rear of the base bears a small silver metal label engraved: Keuffel & Esser (/) New York. F. F. NICKEL is painted underneath the base.

  Keuffel & Esser Company of New York sold versions of the Thacher cylindrical slide rule from at least 1883 until about 1950. There were two models, one with a magnifying glass (K&E model 1741, later K&E model 4013), and one without (K&E model 1740, later K&E 4012). This is a model 1740. The front right corner of the instrument's metal frame is engraved with the number 107. A paper K&E label on the inside lid of the instrument's mahogany case is marked in ink: 1740/661 (/) Thachers (/) Calculating (/)Instr. The top front of the bottom of the case is also carved with 661. In 1887, the model 1740 sold for $30.00.

  Frank Ferdinand Nickel purchased this example around 1883 and donated it to the Smithsonian in 1945, through his son, Henry W. Nickel. The elder Nickel was born in Hanau, Germany, in 1857. He came to the United States around 1883 and worked as a mechanical engineer in New York, Ohio, Pennsylvania, and New Jersey. He also taught at Columbia University in the 1910s. He wrote Direct-Acting Steam Pumps (New York: McGraw-Hill, 1915).

  See also 1987.0107.08 and 1987.0808.01.

  References: Edwin Thacher, "Slide-Rule" (U.S. Patent 249,117 issued November 1, 1881); "Thacher's Calculating Instrument or Cylindrical Slide Rule," Engineering News 16 (18 December 1886): 410; Wayne E. Feely, "Thacher Cylindrical Slide Rules," The Chronicle of the Early American Industries Association 50 (1997): 125–127; Wilfred Scott Downs, ed., "Nickel, Frank F.," Who's Who in Engineering, vol. 3 (New York, 1931), 957; Catalogue of Keuffel & Esser (New York, 1887), 128. This was the first K&E catalog to list the model 1740.

  Location

  Currently not on view

  date made

  ca 1883

  maker

  Stanley, William Ford

  Keuffel & Esser Co.

  ID Number

  MA.312866

  accession number

  169701

  catalog number

  312866

  Data Source

  National Museum of American History

• 

  Keuffel & Esser 4015 Fuller's Spiral Cylindrical Slide Rule

  Description

  This rule consists of an outer wooden cylinder that both slides up and down and rotates. Two brass rings lined with felt are inside this cylinder. The cylinder is covered with paper marked with a single spiral logarithmic scale graduated into 7,250 parts and having a length, according to the maker, of 500 inches (nearly 42 feet). This length permitted computations up to four or five significant digits.

  Inside the outer cylinder is a longer wooden cylinder, covered with paper marked with decimal, conversion, and sine tables. A solid mahogany handle is at one end. A brass index is screwed to the top of the handle. A second, longer brass index is screwed to the mahogany base and marked with a scale of equal parts used in finding logarithms. A third, removable, nickel-plated brass cylinder is inside the instrument and attached to the base. There is no case.

  The tables on the middle cylinder include: decimal equivalents of feet and inches in feet; decimal equivalents of quarter weights and pounds in hundredweights; decimal equivalents of ounces and pounds in fractions of a pound; decimal equivalents of pounds, shillings, and pence in fractions of a pound; decimal equivalents of pence in shillings; days of the year as a fraction of the year; decimal equivalents of subunits of an acre; properties of various metals and woods; decimal equivalents of minutes of a degree in degrees; the Birmingham wire gauge; various conversion factors (mostly for weights and measures); and natural sines.

  The outer, sliding cylinder is marked near the top: FULLERS SPIRAL SLIDE RULE. Near the bottom is marked: ENTD. STATS. HALL; STANLEY, Maker, LONDON. The bottom is stamped: 1389. The top of the long brass index is engraved: 1389 (/) 1901. According to Wayne Feely, these numbers indicate the instrument has serial number 1389 and was made by Stanley in 1901. A white celluloid tag affixed to the handle reads: KEUFFEL & ESSER CO. (/) ST. LOUIS. CHICAGO. (/) NEW YORK. (/) U.S.A. In the 1901 Keuffel & Esser catalog, Fuller's Spiral Slide Rule is listed as Model 4015 and priced at $30.00.

  See also 311958, 1998.0046.01, and 316575.

  References: Wayne E. Feely, "The Fuller Spiral Scale Slide Rule," Chronicle of the Early American Industries Association 50, no. 3 (1997): 93–98; Catalogue of Keuffel & Esser (New York, 1901), 290; James J. Fenton, "Fuller's Calculating Slide-Rule," Transactions and Proceedings of the Royal Society of Victoria 22 (1886): 57–61; Dieter von Jezierski, Slide Rules: A Journey Through Three Centuries, trans. Rodger Shepherd (Mendham, N.J.: Astragal Press, 2000), 42–43; George Fuller, Instructions for the Use of the Fuller Calculator (London: W. F. Stanley & Co., Ltd., [about 1950]), http://www.mccoys-kecatalogs.com/KEManuals/4015/4015.htm. An 1879 first edition of the instructions manual was received with the instrument and is stored in the accession file.

  Location

  Currently not on view

  date made

  1901

  inventor

  Fuller, George

  retailer

  Keuffel & Esser Co.

  maker

  Stanley, William Ford

  ID Number

  MA.313751

  catalog number

  313751

  maker number

  1380/1901

  accession number

  179682

  Data Source

  National Museum of American History

• 

  Keuffel & Esser 1742 Fuller's Spiral Cylindrical Slide Rule

  Description

  This rule consists of an outer wooden cylinder that both slides up and down and rotates. Two brass rings lined with felt are inside this cylinder. The cylinder is covered with paper marked with a single spiral logarithmic scale graduated into 7,250 parts and having a length, according to the maker, of 500 inches (nearly 42 feet). Inside the outer cylinder is a longer wooden cylinder, covered with paper marked with decimal, conversion, and sine tables, and half-lined with felt. A solid mahogany handle is at one end. A brass index is screwed to the top of the handle. A second, longer brass index is screwed to the mahogany base and marked with a scale of equal parts used in finding logarithms. A third and removable brass cylinder is inside the instrument and attached to the base.

  The tables on the middle cylinder include: decimal equivalents of feet and inches in feet; decimal equivalents of quarter weights and pounds in hundredweights; decimal equivalents of ounces and pounds in fractions of a pound; decimal equivalents of pounds, shillings, and pence in fractions of a pound; decimal equivalents of pence in shillings; days of the year as a fraction of the year; decimal equivalents of subunits of an acre; properties of various metals and woods; decimal equivalents of minutes of a degree in degrees; the Birmingham wire gauge; various conversion factors (mostly for weights and measures); and natural sines.

  The outer, sliding cylinder is marked near the top: FULLERS SPIRAL SLIDE RULE. Near the bottom is marked: ENTD. STATS. HALL; STANLEY, Maker, LONDON. The bottom of the outer cylinder and the top of the long brass index are stamped: 858. According to Wayne Feely, the serial number 858 dates this instrument to 1895 or 1896.

  The rule is in a rectangular mahogany case marked in script on the top: Calculator. A paper Keuffel & Esser label on the inside lid of the instrument's mahogany case is marked in ink: 1742 (/) Fuller's (/) Spiral (/) Slide Rule. Fuller's Spiral Slide Rule was first listed in Keuffel & Esser's 1895 catalog and sold for $28.00.

  George Fuller, professor of civil engineering at Queen's University in Belfast, Ireland, patented this instrument in 1878. The Stanley firm made about 14,000 Fuller's spiral slide rules over nearly one hundred years, with K&E distributing a large share of the instruments sold in the United States. The Naval Engineering Division of the U.S. Coast Guard transferred this example to the Smithsonian in 1959. The Coast Guard engineers provided brief instructions:

  "To calculate (5 X 6 X 4)/3 turn the outer cylinder until the first factor (5) is opposite the fixed pointer, set the slot in the movable indicator to read (0), turn the outer cylinder until the second factor (6) appears opposite the movable indicator. (The result will be found on the outer cylinder opposite the first indicator.) To multiply by the third factor (4), set the slot in the movable indicator to (0), turn the outer cylinder until the movable indicator indicates the third factor (4); (the result will be found opposite the fixed indicator.) To divide by (3) set the movable indicator to (3), turn outer cylinder until the slot in the movable indicator is (0) on the outer cylinder and the result will be found opposite the fixed pointer."

  See also MA.311958, 1998.0046.01, and MA.313751.

  References: William Ford Stanley, Surveying and Leveling Instruments, 3rd ed. (London, 1901), 542–543; Wayne E. Feely, "The Fuller Spiral Scale Slide Rule," Chronicle of the Early American Industries Association 50, no. 3 (1997): 93–98; Catalogue of Keuffel & Esser (New York, 1895), 190.

  Location

  Currently not on view

  date made

  1895-1896

  maker

  Keuffel & Esser Co.

  Stanley, William Ford

  ID Number

  MA.316575

  accession number

  225751

  catalog number

  316575

  Data Source

  National Museum of American History

• 

  Dancing Leg Calipers

  Description

  Calipers are used to measure round objects, both around the outside (machine parts, rifle shot) and from the inside (a rifle barrel). They were often included in cases of drawing instruments in the 18th and 19th centuries and shaped like the human body, mainly for the enjoyment of the machinist or draftsman. This pair is missing its set screw and has been welded into a fixed position. It has no identifying marks.

  Reference: Maya Hambly, Drawing Instruments: 1580–1980 (London: Sotheby's Publications, 1988), 73, 88.

  Location

  Currently not on view

  date made

  19th century

  ID Number

  MA.316932

  accession number

  219305

  catalog number

  316932

  Data Source

  National Museum of American History

• 

  Amsler Type 2 Polar Planimeter Sold by Crosby Steam Gage & Valve

  Description

  This German silver instrument has a 4" arm with tracer point and 6" pole arm with short cylindrical weight. The arm lengths are fixed. The tracer arm and pole arm are connected by a hinge and form a circle around the measuring wheel, vernier, and registering dial when the instrument is closed. The top of the pole arm is marked in script: Crosby Steam Gage & Valve Co. Boston. The top of the weight is marked: 16378 (/) 10 [square] in. A serial number is marked underneath the tracer arm and the weight: 10259.

  A wooden case is covered with black leather and lined with purple velvet. The top of the case is marked: CROSBY STEAM GAGE & VALVE C^o (/) BOSTON.

  To measure the areas of diagrams produced by its steam engine indicators, Crosby imported and sold Amsler polar planimeters of types 1, 2, and 3. The presence of a registering dial and the screw thread on the post extending from the measuring wheel indicates that this example is a type 2. Planimeter expert Joachim Fischer dated this object to about 1882. Charles W. Batchelor (1845–1910), the father of the donor, used it in his work as one of Thomas A. Edison's chief assistants. For instance, between 1884 and 1888, he managed the Edison Machine Works, where a planimeter may have been especially useful. From 1888 to at least 1907, Crosby sold the Amsler type 2 in a case for $25.00. For information on Amsler and his invention, see 1987.0107.10. Compare to 1989.0305.01.

  References: Crosby Steam Gage & Valve Co. Catalogue (Boston, 1888), 104–109; Crosby Steam Gage & Valve Co. Catalogue (Boston, 1900), 170–176; Crosby Steam Gage & Valve Co. Catalogue (Boston, 1907), 203–210; Crosby Steam Gage & Valve Company, Practical Instructions Relating to the Construction and Use of the Steam Engine Indicator (Boston, 1911), 43–46, 83–86; Craig Bliss, The Crosby Steam Gage & Valve Co., http://www.crosby-steam.com/index.htm.

  Location

  Currently not on view

  date made

  1880s

  distributor

  Crosby Steam Gage & Valve Company

  maker

  Amsler, Jacob

  ID Number

  MA.318485

  catalog number

  318485

  accession number

  233749

  Data Source

  National Museum of American History

• 

  Straight Edge Signed I. R. C. Co.

  Description

  This undivided black hard-rubber rule is beveled along both long edges. It is marked: I. R. C. CO. (/) GOODYEAR. Scratched on the back of the rule is: Brereton. IRC, or Inoue Rubber Company, was established in Japan in 1926 to make bicycle tires and tubes. The reference to Goodyear is likely to the manufacturing process pioneered by Charles Goodyear and not to the Goodyear Tire & Rubber Company. Brereton was presumably the original owner of the instrument, which was acquired by the Museum in 1961. Compare to MA.327306.

  Reference: IRC Tire, "About Us," http://www.irc-tire.com/en/bc/company/

  Location

  Currently not on view

  date made

  1926–1961

  ID Number

  MA.319738

  accession number

  239019

  catalog number

  319738

  Data Source

  National Museum of American History

• 

  Coradi Precision Disc Polar Planimeter

  Description

  This polar planimeter has a German silver tracer arm that is evenly divided to half-millimeters and numbered from 8 to 66. (One unit is equivalent to 5mm.) The tracer point is bronzed brass and steel and has a support. The length of the tracer arm may be adjusted by thumbscrews on a bronzed brass carriage. A hinged horizontal extension from the carriage holds a white plastic vernier, measuring wheel, and registering dial. The wheel rests on a black-coated aluminum disc faced with white paper. The wheel and disc both rotate when the tracer point is moved. The disc regulates the motion of the wheel, so that it is not affected by folds or other uneven points in the paper with the diagram to be traced.

  A bronzed brass holder for the disc is marked: G. Coradi. Zürich. Switzerland (/) No 4012. The holder rests in the middle of a round brass weight that is 6" in diameter. An oblong German silver testing rule is marked for 0", 1", 2", and 3". It is also marked: G. Coradi Zürich. An oblong brass testing rule is marked for inches and for 0, 50, and 100mm. It is also marked: G. Coradi Zürich.

  A wooden case covered with black morocco leather is lined with purple velvet. A printed paper chart is pasted inside the case. The chart has columns for Scales, Position of the vernier on the tracer bar, Value of the unit of the vernier on the measuring roller, and Constant. The values in the Position and Constant columns are handwritten in the same hand that indicates the Coradi firm manufactured this planimeter with serial number 4,012 on March 25, 1916.

  Gottlieb Coradi (1847–1929) began to make wheel and disc polar planimeters in the early 1880s. The Interstate Commerce Commission transferred this instrument to the Smithsonian in 1962. There is no record of where the ICC purchased the planimeter, but American firms such as Keuffel & Esser (1906–1936 as model 4251) and Dietzgen (by 1926, as model 1808) distributed Coradi's precision disc planimeter. K&E sold it for $95.00 in 1906, for $85.00 in 1909 and, by special order, for $215.00 in 1936. Dietzgen charged $127.00 in 1926. ID number 1977.0112.02 is an instruction manual.

  References: Clark McCoy, "Collection of Pages from K&E Catalogs for the 4251 Family of Precision Polar Disc Planimeters," http://www.mccoys-kecatalogs.com/PlanimeterModels/ke4251family.htm; Catalogue of Keuffel & Esser, 32nd ed. (New York, 1906), 336; Catalogue of Keuffel & Esser, 33rd ed. (New York, 1909), 324; Catalogue of Keuffel & Esser, 38th ed. (New York, 1936), 343; Catalogue & Price List of Eugene Dietzgen Co., 12th ed. (Chicago, 1926), 183.

  Location

  Currently not on view

  date made

  1916

  maker

  Coradi, Gottlieb

  ID Number

  MA.321745

  catalog number

  321745

  accession number

  246883

  Data Source

  National Museum of American History

• 

  Coradi Compensating Polar Planimeter Sold by Keuffel & Esser (Model 4240)

  Description

  This instrument has two arms. The first arm is 9" long. Made of German silver, it has a brass and steel tracer point. The arm is evenly divided into tenths and numbered from 5 to 38. It fits into a brass carriage, painted black, which also holds a white plastic measuring wheel, vernier, and registering dial. Screws on the carriage adjust the length of the tracer arm. The carriage is marked: No 22241.

  An 8" brass (painted black) pole arm fits into a hole in the carriage. A cylindrical brass weight is attached to the other end. The arm is marked: G. Coradi, Zürich Switzerland Keuffel & Esser Co New York. An oblong steel testing plate is marked for 0", 1", 2", and 3". It is also marked: G. Coradi Zürich.

  A wooden case covered with black leather is lined with purple velvet. A printed paper chart is pasted inside the case. The chart has columns for Scales, Position of the vernier on the tracer bar, Value of the unit of the vernier on the measuring roller, and Constant. The values in the Position and Constant columns are handwritten in the same hand that indicates the Coradi firm manufactured this planimeter with serial number 22,241 on July 15, 1914. Keuffel & Esser stamped the chart with its model number, 4240.

  Gottlieb Coradi (1847–1929) began to make wheel and disc polar planimeters in the early 1880s. In 1894 he made the pole arm higher than the tracer arm and connected the arms with a ball joint. This "compensating" planimeter could trace in both the clockwise and counterclockwise directions, preventing errors introduced by planimeters made in the Amsler style. In 1901 K&E began selling Coradi's compensating planimeter for $36.00. In 1936 the firm began offering the planimeter under the company's Paragon brand name and charged $49.00. K&E stopped selling the instrument in 1939. The Interstate Commerce Commission transferred this example to the Smithsonian in 1963. ID number 1977.0112.02 is an instruction manual.

  References: Peggy Aldrich Kidwell, "Planimeter," in Instruments of Science: An Historical Encyclopedia, ed. Robert Bud and Deborah Jean Warner (London: Garland Publishing, 1998), 467–469; "The Lang-Coradi Planimeter," in Olaus Henrici, "On Planimeters," in Report of the Sixty-fourth Meeting of the British Association for the Advancement of Science (London, 1894), 496–523, on 515; Clark McCoy, "Collection of Pages from K&E Catalogs for the 4240 Family of Polar Planimeters," http://www.mccoys-kecatalogs.com/PlanimeterModels/ke4240family.htm; Catalogue of Keuffel & Esser, 33rd ed. (New York, 1909), 323; Catalogue of Keuffel & Esser, 38th ed. (New York, 1936), 256.

  Location

  Currently not on view

  date made

  1914

  distributor

  Keuffel & Esser Co.

  maker

  Coradi, Gottlieb

  ID Number

  MA.321777

  catalog number

  321777

  accession number

  246883

  Data Source

  National Museum of American History

• 

  Keuffel & Esser 4012 Thacher Cylindrical Slide Rule

  Description

  The brass core of this cylindrical slide rule is covered by 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 and 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.

  The paper of instructions and rules for operating THACHER'S CALCULATING INSTRUMENT, normally glued to the top front of the base, is coming loose and is torn on this example. A large chip is also missing from the left handle. The top back of the base is stamped: KEUFFEL & ESSER CO. (encircling N.Y.); 4012 (/) 4218; TRADEMARK (below the K&E logo of a lion).

  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 1915. The marking on the core also no longer references W. F. Stanley, the English firm that originally manufactured the instrument for sale by K&E. Stanley continued to provide the engine-divided scales after K&E began making the rest of the instrument in 1887. K&E took over printing the scales in the 1910s. Model 4012 sold for $35.00 in 1916, $60.00 in 1922, and $70.00 in 1927.

  Compare markings on the core to MA.322730. See also MA.312866 and MA.326628.

  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 1915

  maker

  Keuffel & Esser Co.

  ID Number

  MA.323504

  accession number

  251559

  maker number

  4218

  catalog number

  323504

  Data Source

  National Museum of American History

• 

  Improved Willis Planimeter

  Description

  The Willis planimeter is an adaptation of the standard polar planimeter that allows the user to determine mean effective pressure directly from the diagram made by a steam engine pressure indicator. The German silver instrument has two pivoted tracer arms. The length of one of these may be adjusted. This adjustable arm is graduated along one edge to 32nds of an inch from 2" to 8-1/2". The rectangular pivot attaches on the right side to a frame of three metal rods. The front rod is plain. The middle rod is made of a dark or tarnished metal and carries a brass wheel that slides on a carriage of two small double wheels. The third rod holds a wooden triangular ruler with six scales on white celluloid. These scales divide the inch into 100, 50, 60, 30, 80, and 40 parts. The ruler is marked: U. S. ST'D.

  Two clasps on the left side of the rectangular pivot secure the frame. That side is marked: —IMPROVED — (/) WILLIS PLANIMETER (/) MANF'D BY (/) JAMES L. ROBERTSON & SONS (/) NEW YORK, U.S.A. The right side of the pivot is marked: PAT'D SEPT. 22, 1896 (/) OCT. 6, 1896 (/) 838. A wooden case covered with black leather is lined with purple satin and velvet. The inside of the lid is marked: Improved Willis Planimeter, (/) PATENTED SEPTEMBER 22, 1896. (/) " OCTOBER 6, 1896. (/) MANUFACTURED BY (/) JAMES L. ROBERTSON & SONS, (/) New York, U. S. A.

  For an attachment to this instrument, see MA.323704. Compare to 1994.0356.01 and MA.324247. Although this instrument (serial number 838) was presumably manufactured soon after 1994.0356.01 (serial number 749), note the differences in the construction of the measuring wheel on the frame attachment. Charles F. Engman (d. 1927) of New York City used this instrument. He was a marine engineer with the Clyde Line for several years and patented a device for automatically oiling engines. Around 1900, he joined the U.S. Navy. He served as chief engineer on a number of colliers, cargo ships that carried coal, until the end of World War I.

  References: Edward J. Willis, "Planimeter" (U.S. Patent 529,008 issued November 13, 1894; reissued as 11,568 September 22, 1896), "Planimeter" (U.S. Patent 542,511 issued July 9, 1895), and "Planimeter" (U.S. Patent 672,581 issued April 23, 1901); Alpheus C. Lippincott, "Planimeter" (U.S. Patent 569,107 issued October 6, 1896); Charles F. Engman, "Lubricator" (U.S. Patent 596,863 issued January 4, 1898); catalog of James L. Robertson & Sons (New York, [1899]), 29–31; Hyman A. Schwartz, "The Willis Planimeter," Rittenhouse 7, no. 2 (1993): 60–64.

  Location

  Currently not on view

  date made

  1896-1901

  maker

  James L. Robertson & Sons

  ID Number

  MA.323703

  accession number

  252501

  catalog number

  323703

  Data Source

  National Museum of American History

• 

  Horsepower Attachment for Improved Willis Planimeter

  Description

  In 1895 Edward J. Willis of Richmond, Va., modified the design of the planimeter he patented in 1894, adding the frame found on 1994.0356.01, MA.324247, and MA.323703. He also devised an attachment that would allow users to directly read the horsepower produced by a steam engine, instead of having to calculate it from the mean effective pressure given by his planimeter. Between 1899 and 1905, James L. Robertson & Sons started to sell the attachment and a set of tables for making readings, charging $20.00 in addition to the $18.00 price for the Improved Willis Planimeter.

  Charles F. Engman, who owned this horsepower attachment, purchased his planimeter (MA.323703) before 1901. It is likely he bought the attachment at the same time. The German silver instrument has two rectangular scales, held together at one end with a thumbscrew. Each of the scales is 13" long. On one side, they are divided into 200 units, for the 200 maximum revolutions per minute of slow-speed engines. On the other, they are divided into 750 units, for the maximum 750 rpm of high-speed engines. One of the scales is marked at one end on the high-speed side with a serial number: 111.

  Two slides with adjustable thumbscrews are placed on the scales. Points on the slides grip the paper. Corks are placed over the points to protect the case when the instrument is stored. A tracer arm is 13" long and may replace the tracer arm on a Willis planimeter. The planimeter is then used on top of the attachment, with the measuring wheel on one scale and the tracer point on the other.

  A wooden case covered with black leather is lined with purple satin and velvet. The inside of the lid is marked: HORSE POWER ATTACHMENT (/) FOR THE (/) Improved Willis Planimeter. (/) PATENTED JULY 9th, 1895. (/) Manufactured by JAMES L. ROBERTSON & SONS, (/) NEW YORK, U. S. A.

  References: Edward J. Willis, "Planimeter" (U.S. Patent 529,008 issued November 13, 1894; reissued as 11,568 September 22, 1896) and "Planimeter" (U.S. Patent 542,511 issued July 9, 1895); catalog of James L. Robertson & Sons (New York, [1899]), 29–31; James L. Robertson & Sons, Steam-Engine Indicators and Their Attachments (New York, 1905), 23; Hawkins' Indicator Catechism (New York: Theo. Audel & Co., 1903), 135–139; Hyman A. Schwartz, "The Willis Planimeter," Rittenhouse 7, no. 2 (1993): 60–64.

  Location

  Currently not on view

  date made

  1899-1901

  maker

  James L. Robertson & Sons

  ID Number

  MA.323704

  catalog number

  323704

  accession number

  252501

  Data Source

  National Museum of American History

• 

  Coffin Planimeter Arm Signed by Ashcroft Manufacturing Company, No. 830

  Description

  This German silver instrument is a curved bar with a short arm, on which a short cylindrical weight is placed, and a longer arm, to which a tracer point is screwed. The middle of the bar has a thin cross-rod, on which a measuring wheel rotates against a wedge-shaped vernier. The wheel is numbered from 0 to 14, with each unit divided into five parts. The bar is marked: THE ASHCROFT MFG. CO. (/) — SOLE MANUFACTURERS. — (/) COFFIN'S PAT. JUNE 6. 1882. The underside of the bar is marked: No. 830. The serial number suggests this object predates 1987.0107.03. Compare also to MA.323708 and MA.323706.

  A wooden case covered with dark brown leather is lined with purple silk and velvet. The top of the case is marked: MADE BY (/) THE ASHCROFT MANF'G CO. (/) NEW YORK & BRIDGEPORT.

  John Coffin of Syracuse, N.Y., applied for a patent on this variation on a planimeter in July 1881. He designed his "averageometer" to calculate areas in diagrams of work performed by steam engines. The Ashcroft Manufacturing Company of New York City and Bridgeport, Conn., was the first of several American firms to make the device.

  Ashcroft, best known for making pressure gauges for steam engines, often sold the arm for Coffin's planimeter separately from its base, as in this example. In 1910, Frederick C. Blanchard, Ernest B. Crocker, and Philip G. Darling, who all probably worked for Ashcroft, patented an improvement to Coffin's planimeter so that it could be clamped in place. The planimeters made by Ashcroft after 1910 utilized this improvement, so this example was made between 1882 and 1910.

  References: John Coffin, "Averageometer, or Instrument for Measuring the Average Breadth of Irregular Planes" (U.S. Patent 258,993 issued June 6, 1882); F. C. Blanchard, E. B. Crocker, and P. G. Darling, "Planimeter" (U.S. Patent 961,836 issued June 21, 1910); David R. Green, "Coffin Planimeters," June 16, 2008, http://www.planimetervault.com/coffin.html; N. Hawkins, Hawkins' Indicator Catechism (New York: Theo. Audel & Co., 1903), 140–142.

  Location

  Currently not on view

  date made

  1882-1910

  maker

  Ashcroft Mfg. Co.

  ID Number

  MA.323705

  catalog number

  323705

  accession number

  252307

  Data Source

  National Museum of American History

• 

  Bushnell-Coffin Planimeter Sold by American Schaeffer & Budenberg Corporation

  Description

  On August 18, 1902, Levi T. Snow of New Haven, Conn., filed a U.S. patent application for improvements to the planimeter invented in 1882 by John Coffin for measuring the area under curves drawn by the gauge on a steam engine. (See MA.323708, MA.323705, and 1987.0107.03.) For instance, Snow added a tube containing a set of scales for the pressures under which the diagrams were made. He assigned the patent to the John S. Bushnell Company of New York City, which manufactured and sold the instrument as "Bushnell's Improved Planimeter" and the "Bushnell-Coffin Planimeter."

  This Bushnell-Coffin planimeter consists of an aluminum base with four black rubber feet. Two aluminum rods are screwed to the base, with a movable indicator on one rod and a sliding tube marked with six sets of scales for pressures on the other rod. A rectangular support for the planimeter arm is bolted to the base at the left end of the rods. The serial number 303 is stamped next to this support.

  A smaller rectangular aluminum base slides between two bars on the right side of the larger base. Both bases have clamps for holding paper diagrams. The aluminum planimeter arm is a single curved bar. One end of the arm and a short cylindrical weight fit into a hole on the movable indicator. The other end of the arm has a tracer point that moves over the diagram held on the bases. A single bar near the weighted end of the arm has a brass vernier and a brass measuring wheel, which is numbered from 0 to 14, with each unit divided into five parts.

  A wooden case covered with black leather is lined with blue velvet. The top of the case is marked: Bushnell – Coffin Planimeter. The left end of the case is marked: A–5. The right side of the case is marked: M.E. LAB. (/) COFFIN. A flap inside the lid holds the smaller base and flips up, perhaps to store extra paper. A ribbon on the flap has an oval logo marked: AMERICAN * SCHAFFER & BUDENBERG. Inside the oval are a picture of a steam engine gauge and the words: BROOKLYN, N.Y.

  By 1916, the John S. Bushnell Company was making the Bushnell-Coffin Planimeter and the American Steam Gauge & Valve Manufacturing Company was selling it for $55.00. In 1923, American Steam Gauge, the Hohmann-Nelson Company, and the American division of the Schäffer & Budenberg Manufacturing Company merged to form American Schaeffer & Budenberg Corporation. The firm may have been purchased by Manning, Maxwell, and Moore in the late 1930s. The mechanical engineering laboratory of New York University owned this instrument.

  References: Levi T. Snow, "Planimeter" (U.S. Patent 718,166 issued January 13, 1903); David R. Green, "Coffin Planimeters," June 16, 2008, http://www.planimetervault.com/coffin.html; "The Bushnell Improved Coffin Planimeter," The Engineer's List 11, no. 11 (November 1902): 37–38; American Steam Gauge & Valve Manufacturing Co., Catalog No. 65 (Boston, 1916), 810; advertisement for the Bushnell-Coffin Planimeter, Power 49, no. 25 (June 24, 1919): 105; Barry Lee David, The Antique American Steam Gauge: A Collector's Guide (Mendham, N.J.: Astragal Press, 2003).

  Location

  Currently not on view

  date made

  1923-ca 1937

  maker

  John S. Bushnell Company

  ID Number

  MA.323706

  catalog number

  323706

  accession number

  252307

  Data Source

  National Museum of American History

• 

  Coradi Polar Planimeter

  Description

  This instrument has two arms. The German silver tracer arm has a support for the tracer point and is evenly divided by tenths numbered from 10 to 37. Ten units are equivalent to 5mm. The tracer arm fits within a carriage of brass, painted black, that also holds a white plastic measuring wheel and vernier and a metal registering dial. The pole arm is made of brass painted black and is attached to the carriage. The end of the pole arm fits into a rectangular metal weight faced with brass painted black. The weight is marked: G. Coradi Zürich (/) N^o 759. The bottom of the weight is covered with paper. A cylindrical brass weight fits into a hole on top of the pole arm. The testing rule is missing.

  A wooden case covered with black leather is lined with purple velvet. A paper printed chart glued inside the lid has columns in German for Scales, Position of the vernier on the tracer bar, Value of the unit of the vernier on the measuring roller, and Constant. The values are handwritten. The date on the chart indicates the Coradi firm made serial number 759 on December 28, 1888.

  Gottlieb Coradi (1847–1929) established a workshop in Zurich in 1880 and began making wheel and disc polar planimeters in the Amsler style soon thereafter. In 1894, he modified the design into the "compensating" polar planimeter; see MA.321777. Union College donated this instrument in 1964.

  Reference: "People: Gottlieb Coradi," Waywiser, Harvard University Department of the History of Science, http://dssmhi1.fas.harvard.edu/emuseumdev/code/eMuseum.asp?lang=EN.

  Location

  Currently not on view

  date made

  1888

  maker

  Coradi, Gottlieb

  ID Number

  MA.323707

  catalog number

  323707

  accession number

  252804

  Data Source

  National Museum of American History

• 

  Prototype for Planimeter Invented by John Coffin

  Description

  This German silver L-shaped bar has a pivoting rectangular piece underneath the end of its short leg. A small cylindrical handle and a tracer point are at the end of the long leg. A measuring wheel at the vertex is numbered from 0 to 10 to 0. The divisions are engine-divided and thus finely made.

  The instrument fits into a crudely made wooden case. The lid of the case has two German silver tracks, two German silver clamps for holding paper, and a German silver pivoting arm that may be used to secure one of the clamps. The rectangular piece on the instrument slides into one of the tracks so that the tracer point can be moved along a curve drawn on paper in the holders. The measuring wheel thus found the area under the curve, which was produced by a steam engine indicator.

  John Coffin of Syracuse, N.Y., applied for a patent on this variation of a planimeter in July 1881. Although several companies subsequently manufactured forms of Coffin's planimeter, this example resembles none of the production models identified by collector David R. Green or depicted by N. Hawkins or James Ambrose Moyer. However, this instrument is very similar to Coffin's patent drawings. This similarity, the crude construction of the case, and the absence of maker signatures and identifying marks suggest that this version of Coffin's planimeter was not made in large quantities. Perhaps it was even a patent model, since Coffin did submit one with his application. The Museum owns patent models from as late as 1910, and this object came to the Smithsonian some time before it was found in the collections in 1964. According to Janssen, no list was made of the 15,000 models received in 1926, although all of the 1,000 models collected in 1908 were recorded and accessioned. There is no Patent Office tag on this instrument.

  Coffin announced in his patent specification that he would soon move to Chicago, and there is no record of his activities after 1882. Compare this object to 1987.0107.03, MA.323705, and MA.323706.

  References: John Coffin, "Averageometer, or Instrument for Measuring the Average Breadth of Irregular Planes" (U.S. Patent 258,993 issued June 6, 1882); N. Hawkins, Hawkins' Indicator Catechism (New York: Theo. Audel & Co., 1903), 140–142; James Ambrose Moyer, Power Plant Testing (New York: McGraw-Hill, 1911), 73–78; David R. Green, "Coffin Planimeters," The Planimeter Vault, June 16, 2008, http://www.planimetervault.com/coffin.html; Barbara Suit Janssen, Patent Models Index: Guide to the Collections of the National Museum of American History (Washington, D.C.: Smithsonian Institution Scholarly Press, 2010), i:viii–ix, 150.

  Location

  Currently not on view

  date made

  1881

  maker

  Coffin, John

  ID Number

  MA.323708

  catalog number

  323708

  accession number

  252312

  Data Source

  National Museum of American History

• 

  Improved Willis Planimeter

  Description

  This metal instrument (possibly of nickel-plated brass) has two pivoted arms with needle points. One is about 9" long, and the other is about 6-1/2" long. The longer arm is used for tracing and is graduated to 32nds of an inch from 2" to 8-1/2". A screw on top of the rectangular pivot joining the arms allows the longer arm to be set at different lengths. The pivot is marked on the left side: —IMPROVED — (/) WILLIS PLANIMETER (/) MANF'D BY (/) JAMES L. ROBERTSON & SONS (/) NEW YORK U.S.A. There are two clasps on the left side. The right side of the pivot is marked: PAT'D SEPT. 22, 1896 (/) OCT. 6, 1896 (/) APRIL 23, 1901 (/) 8390.

  A metal frame has three bars, and the first bar is unadorned. The second bar is made of a dark-colored metal. A dark-colored metal wheel slides along the bar in a carriage made of four small wheels. The third bar holds a wooden triangular ruler with six scales on white celluloid. These scales divide the inch into 100, 50, 60, 30, 80, and 40 parts. The ruler is marked: J. L. ROBERTSON & SONS, N.Y. The frame fits into three holes on the right side of the pivot that joins the arms. A second triangular scale in the case divides the inch into 70, 20, 16, 12, 10, and 8 parts. It is also marked: J. L. ROBERTSON & SONS, N.Y.

  A wooden case is covered with black leather and lined with purple satin and velvet. The inside of the lid is marked: Improved Willis Planimeter, (/) PATENTED SEPTEMBER 22, 1896. (/) " OCTOBER 6, 1896. (/) " APRIL 23, 1901 (/) MANUFACTURED BY (/) JAMES L. ROBERTSON & SONS, (/) INC. (/) New York, U. S. A. Three blue thumbtacks are inside the case.

  Edward Jones Willis (1866–1941), a steam and electrical engineer from Richmond, Va., patented a cross-shaped planimeter in 1894 and had a modified version of the patent reissued in 1896. This is the first patent mentioned on the instrument. Willis's 1895 patent for a planimeter with a frame similar to the frame on this example and a horsepower attachment is not mentioned on the instrument; see MA.323704. Alpheus C. Lippincott of New York City received the second patent mentioned on this instrument, for a different form of cross-shaped planimeter.

  James L. Robertson & Sons manufactured steam engine indicators. Since planimeters were used to measure the area under curves drawn by these indicators, it was common for firms that made indicators to also produce planimeters. Indeed, Robertson sold both the Improved Willis Planimeter and the Lippincott Planimeter, so it is probable that the company mentioned Lippincott's patent on this planimeter by mistake.

  In 1901 Willis patented the form of wheel mount found on this instrument, which Robertson manufactured and sold as the Improved Willis Planimeter. Its price was $18.00 in 1905. The company apparently ceased operations in the 1910s. The serial number (8390) and patent references on this instrument indicate that it postdates 1994.0356.01 and MA.323703. Willis made further design changes in the 1920s; see 1983.0173.01. Lincoln F. Spencer, a stationary engineer in Massachusetts, used this instrument in the early 20th century.

  References: Edward J. Willis, "Planimeter" (U.S. Patent 529,008 issued November 13, 1894; reissued as 11,568 September 22, 1896), "Planimeter" (U.S. Patent 542,511 issued July 9, 1895), and "Planimeter" (U.S. Patent 672,581 issued April 23, 1901); Alpheus C. Lippincott, "Planimeter" (U.S. Patent 569,107 issued October 6, 1896); James L. Robertson & Sons, Steam-Engine Indicators and Their Attachments (New York, 1905), 21–22; Hyman A. Schwartz, "The Willis Planimeter," Rittenhouse 7, no. 2 (1993): 60–64.

  Location

  Currently not on view

  date made

  1901-ca 1910

  maker

  James L. Robertson & Sons

  ID Number

  MA.324247

  accession number

  253403

  catalog number

  324247

  Data Source

  National Museum of American History

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