#
Engineering, Building, and Architecture

Not many museums collect houses. The National Museum of American History has four, as well as two outbuildings, 11 rooms, an elevator, many building components, and some architectural elements from the White House. Drafting manuals are supplemented by many prints of buildings and other architectural subjects. The breadth of the museum's collections adds some surprising objects to these holdings, such as fans, purses, handkerchiefs, T-shirts, and other objects bearing images of buildings.

The engineering artifacts document the history of civil and mechanical engineering in the United States. So far, the Museum has declined to collect dams, skyscrapers, and bridges, but these and other important engineering achievements are preserved through blueprints, drawings, models, photographs, sketches, paintings, technical reports, and field notes.

"Engineering, Building, and Architecture - Overview" showing 1251 items.

Page 5 of 126

## Involutes of Circles, Kinematic Model by Martin Schilling, series 24, model 6, number 334

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

- An involute of a circle is a curve that is produced by tracing the end of a string that is wrapped around a circle as it is unwound while being kept taut. It is the envelope of all points that are perpendicular to the tangents of a circle.

- As with the three trochoidal models, these curves were used in the shaping of gear teeth in the 18th century. Following that, it was discovered that shaping the teeth of gears using the curve formed by the involute of a circle also increases the efficiency of gearage. Surprisingly, there are many applications of noncircular gears, such as elliptical, triangular, and quadrilateral gears. (See model 1982.0795.06.)

- In this model a toothed circular gear of radius 13 mm is mounted on the baseplate and can be turned via a crank on the underside of the baseplate. A thick piece of beveled glass is mounted above the apparatus. A dark metal toothed bar 45 mm long is attached to the circular gear so that as the crank turns the circular gear, the toothed bar is forced past the circular gear and rotates round it.

- Perpendicular to the bar is a thin clip with three small colored balls. A blue ball is attached at the edge of the bar where the bar will touch the circle and traces the involute of the circle in blue on the glass. A red ball is placed 33mm in front of the toothed side of the bar and produces a “stretched” involute in red. A green ball is 45mm behind the toothed side of the bar traces another “stretched” involute in green. German title is: Erzeugung von Kreisevolventen.

- References:

- Schilling, Martin,
*Catalog Mathematischer Modelle für den höheren mathatischen Unterricht*, Halle a.s., Germany, 1911, pp 56-57. Series 24, group II, model 6.

- Online demo at Mathworld by Wolfram: http://mathworld.wolfram.com/Involute.html

- Location
- Currently not on view

- date made
- ca 1900

- maker
- Schilling, Martin

- ID Number
- 1982.0795.04

- catalog number
- 1982.0795.04

- accession number
- 1982.0795

- Data Source
- National Museum of American History, Kenneth E. Behring Center

## Cycloids, Kinematic Model by Martin Schilling, series 24, model 7, number 335

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

- The cycloid solves the 17th-century problem posed by Swiss mathematician Johann Bernoulli known as the brachistochrone problem. This problem asks for the shape of the curve of fastest decent: the path that a ball would travel the fastest along under the influence of gravity.

- The cycloids are drawn by tracing the location of a point on the radius of a circle or its extension as the circle rolls along a straight line. Cycloids are members of the family of curves known as trochoids, curves that are generated by tracing the motion of a point on the radius of a circle as it rolls along another curve. The curve generated by a point on the circumference of the rolling circle is called an epicycloid, and a ball rolling on this curve (inverted) would travel faster than on any other path (the brachistochrone problem). Points either inside or outside the rolling circle generate curves called epitrochoids. The cycloid also solves the tautochrone problem, a curve for which a ball placed anywhere on the curve will reach the bottom under gravity in the same amount of time.

- An example of the application of the cycloid as a solution of the tautochrone problem is the pendulum clock designed by Dutch physicist Christopher Huygens. As the width of the swing of the pendulum decreases over time due to friction and air resistance, the time of the swing remains constant. Also, cycloidal curves are used in the shaping of gear teeth to reduce torque and improve efficiency.

- This model consists of a toothed metal disc linked to a bar that is toothed along one edge. A radius of the circle extending away from the bar has a place for a pin inside the circumference, a pin on the circumference, and a pin outside the circle. Rotating a crank below the baseplate of the model moves the circle along the edge of the bar, generating a curve above each point. The curves are indicated on the glass overlay of the mechanism. The curve generated by the point on the circumference of the circle is an epicycloid, depicted in blue on the glass; that generated by the point outside the circle is a prolate (from the Latin to elongate) cycloid, depicted in orange; and that generated by the point inside the circle is a curtate (from the Latin to shorten) cycloid, depicted in green. The German title of this model it: Erzeugung von Cycloiden (to produce cycloids).

- References:

- Schilling, Martin,
*Catalog Mathematischer Modelle für den höheren mathatischen Unterricht*, Halle a.s., Germany, 1911, pp 56-57. Series 24, group II, model 7.

- Online demo at Wofram Mathworld: http://mathworld.wolfram.com/Cycloid.html

- Location
- Currently not on view

- date made
- ca 1900

- maker
- Schilling, Martin

- ID Number
- 1982.0795.05

- catalog number
- 1982.0795.05

- accession number
- 1982.0795

- Data Source
- National Museum of American History, Kenneth E. Behring Center

## Twin Elliptical Gears, Kinematic Model by Martin Schilling, series 24, model 8, number 347

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

- Many machines need to produce a back and forth motion, such as the back and forth motion of the rods of a locomotive that drives the wheels. This back and forth motion is achieved by converting circular motion (produced by the pistons of the steam engine) to linear motion (of the rods). One way of achieving this in a smooth way is through a
*quick return*mechanism. This model uses two ellipses that are held in constant contact, producing an “elliptical gear.”

- As one ellipse rotates around the other, the distance between the fixed focus of one ellipse and the free focus of the other remains constant. This can be seen in the model by the placement of the arm. As the ellipses rotate about each other, the speed of rotation increase as the ellipses move towards a side-by-side orientation, and slows as the ellipses move towards an end-to-end alignment. Thus the velocity increases and decreases periodically as the ellipses rotate. The velocity ratio of the rotating gear is the portion of the length of the top arm over one ellipse divided by the remaining length (over the other ellipse.) Mathematically this velocity ratio varies from
*e/(1-e)*to*(1-e)/e*where*e*is the eccentricity of the (congruent) ellipses. The cyclic nature of the velocity of this motion is known as a “quick-return” mechanism, which converts rotational motion into reciprocating or oscillating motion.

- This model employs two identical elliptical metal plates (major axis 8 cm, minor axis 5 cm). Both ellipses were fixed to the baseplate at their right foci (though one ellipse is now detached) while the other foci are free. This allows the two ellipses to rotate around each other while remaining in contact. An 8 cm rigid arm connects the fixed foci of one ellipse to the free foci of the other.

- Beneath the free foci of the left ellipse is a metal point. As the (now missing) crank below the baseplate is rotated, the point traces out a circle on the paper covering of the baseplate. Using the thumb hold at the midpoint of the arm, the two ellipses can be made to rotate around each other. A small ball-type joint at the ends of the major axis of each ellipse allows the two ellipses to join together when they are aligned end-to-end. The German title of the model is: Gleichläufiges Zwillingskubelgetriebe mit seinen Polbahnen (same shape transmitted by twin cranks with their poles).

- References:

- Cundy, H. M., Rollett, A. P.,
*Mathematical Models*, Oxford University Press, 1961, pp. 230-233.

- Schilling, Martin,
*Catalog Mathematischer Modelle für den höheren mathatischen Unterricht*, Halle a.s., Germany, 1911, pp. 56-57. Series 24, group III, model 8.

- Location
- Currently not on view

- date made
- ca 1900

- maker
- Schilling, Martin

- ID Number
- 1982.0795.06

- catalog number
- 1982.0795.06

- accession number
- 1982.0795

- Data Source
- National Museum of American History, Kenneth E. Behring Center

## Twin Hyperbolic Gears, Kinematic Model by Martin Schilling, series 24, model 9, number 348

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

- This model is an example of a Watt’s linkage. Linkages are joined rods that move freely about pivot points used to produce a certain type of motion. 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 and one area of research during the 19th century was to use linkages to produce linear motion from circular motion. Scottsman James Watt (1736-1819), devised linkages to create linear motion for use in early steam engines. A Watt’s linkage is a three-bar linkage in which two bars of equal length rotate to produce congruent circles. The ends of these two radii are joined by a longer crossbar. As the radii counter-rotate, the midpoint of the crossbar traces out a Watt’s Curve.

- Watt’s Curve is related to the lemniscate, or a figure-eight-shaped curve. However, Watt’s Curve resembles a figure eight that has been compressed vertically so that the two lobes appear as circles that are flattened where they meet. As the midpoint of the crossbar traces the region of the lemniscate where the curve crosses itself, the motion is approximately linear.

- This model consists of two identical components (“bowties”), each comprised of two rounded hyperbolic metal plates (13 cm base, 5.5 cm altitude) joined by an armature of 9 cm. One bowtie is mounted on top of and offset by 7 cm from the bottom bowtie. An armature attaches the vertex of one plate to the vertex of its corresponding plate below. A crank below the baseplate connects to one arm. When the crank is rotated, the two connecting arms rotate in opposing circular paths, causing the top bowties to follow a roughly figure eight path. As each arm rotates through 180 degrees, the bowties align first to the left, then to the right. The German title is of this model it: Gegenläufiges Zwillingskubelgetriebe mit seinen Polbahnen.

- References:

- Guillet, George,
*Kinematics of Machines*, John Wiley & Sons, N.Y., 1930, pp. 217, 218.

*Watt’s Curve*, Mathworld, http://mathworld.wolfram.com/WattsCurve.html

- Schilling, Martin,
*Catalog Mathematischer Modelle für den höheren mathatischen Unterricht*, Halle a.s., Germany, 1911, pp 56-57. Series 24, group III, model 9.

- Location
- Currently not on view

- date made
- ca 1900

- maker
- Schilling, Martin

- ID Number
- 1982.0795.07

- catalog number
- 1982.0795.07

- accession number
- 1982.0795

- Data Source
- National Museum of American History, Kenneth E. Behring Center

## Hart Inversor, Kinematic Model by Martin Schilling, series 24, model 11, number 350

- Description
- Around 1900, American mathematicians introduced ideas to their students using physical models like this one. This model is the eleventh 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 and 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.

- The Hart’s Inversor, also known as Hart’s Cell or Hart’s Linkage, is a contraparallelogram of four pin-connected links. It is similar to the Peaucellier Inversor, but is a four-bar linkage as opposed to a seven-bar linkage. It was invented and published by Harry Hart (1848-1920) in 1874.

- This model is made from four metal armatures, two measuring 9.5 cm, two 16.5 cm, in an “hourglass” configuration (the two longer arms crossing to form the waist of the hourglass) with two congruent triangles meeting at a common vertex.

- When the top and bottom arms are parallel to the top and bottom of the baseplate, the triangles are isosceles. The top arm is fixed to the base slightly to the right of its midpoint. Below this fixed point, a fifth arm is attached to a crank below the baseplate and attached to the underside of the upper cross arm slightly above the midpoint. This attachment can be rotated in a circle either by turning the crank or by using the polished fingerhold on the top of the cross arm.

- A pin below the fingerhold (now inserted into a piece of cork to avoid tearing the paper covering of the baseplate) traces part of a circle as seen in the image. This causes a fingerhold and pin (also in a piece of cork) on the second cross arm, slightly below its midpoint, to move laterally right and left across the baseplate in a straight-line motion. As the attachment is rotated, the triangles become progressively more scalene.

- In addition, this linkage has the following linearity property. When the linkage is in its original (isosceles) configuration, mark four points on each of the four arms such that the four points lie on a vertical line. Fix the top point and allow the second point (below the top point) to trace a circle. This causes the third point to trace a straight line, and all four points will remain colinear regardless of the configuration of the linkage.

- The German title of this model is: Inversor von Hart. The name plate on the model gives a date of 1874 for this model, most likely indicating the date of Hart’s discovery.

- References:

- Schilling, Martin,
*Catalog Mathematischer Modelle für den höheren mathatischen Unterrich*t, Halle a.s., Germany, 1911, pp 56-57. Series 24, group IV, model 11.

- Online demonstrations for this model can be found at www.cut-the-knot.org

- Location
- Currently not on view

- date made
- ca 1900

- maker
- Schilling, Martin

- ID Number
- 1982.0795.08

- catalog number
- 1982.0795.08

- accession number
- 1982.0795

- Data Source
- National Museum of American History, Kenneth E. Behring Center

## Sylvester-Kempe Inversor, Kinematic Model by Martin Schilling, series 24, model 12, number 351

- Description
- Around 1900, American mathematicians introduced ideas to their students using physical models like this one. This model is the twelfth 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 and 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.

- A generalization of Hart’s Inversor, the Sylvester-Kempe Inversor is also known as a Quadruplane inversor and creates linear motion from circular motion. English mathematicians James Sylvester (1814-1897) and Alfred Kempe (1849-1922) developed the geometric theory behind these linkages in the 1870s. Kempe proved that every algebraic curve can be generated by a linkage using a Watt’s curve, after Scottish engineer James Watt (1736-1819).

- Unlike the other Schilling linkages in the collection, this one is not made of armatures. It consists of linked triangular metal plates (two large and two small). The smallest triangle is attached to the baseplate at a stationary pivot point. The triangles are linked together at the vertices to form a chain of triangles (small-large-small-large). As with the other linkages, this model has an armature that is attached to a small hand crank on the underside of the baseplate and attached to the vertex of one of the larger triangles that allows the linkage to rotate. It can also be moved by using one of two fingerholds attached to the top of two of the triangles at a vertex.

- As the linkage is rotated, a pin where the armature attaches to the large triangle traces out a circle, visible in the image. At the same time, a pin under the fingerhold on the opposite large triangle traces a straight line from left to right across the baseplate, also seen in the image. The German title of this model is: Inversor von Sylvester und Kempe. The nameplate on the model gives a date of 1875 for this model, most likely the date of discovery by Sylvester and Kempe.

- Reference:

- Schilling, Martin,
*Catalog Mathematischer Modelle für den höheren mathatischen Unterricht*, Halle a.s., Germany, 1911, pp. 56-57. Series 24, group IV, model 12.

- Location
- Currently not on view

- date made
- ca 1900

- maker
- Schilling, Martin

- ID Number
- 1982.0795.09

- catalog number
- 1982.0795.09

- accession number
- 1982.0795

- Data Source
- National Museum of American History, Kenneth E. Behring Center

## Amsler Type 2 Polar Planimeter

- Description
- This German silver instrument has a 6-1/2" arm with tracer point and 6-1/2" pole arm. The arm lengths are fixed. The tracer arm and pole arm are connected by a hinge and form a circle around the white plastic measuring wheel, vernier, and registering dial when the instrument is closed. The pole weight is missing. The top of the tracer arm is marked in script: J. Amsler. A serial number is marked underneath the tracer arm and the weight: 67925.

- A wooden case is covered with black leather. The corner of a label attached to the bottom of the case is missing. The remaining part reads: SA ROSENHAIN (/) S. Bento, 60 – S. Paulo (/) [illegible] 2. 260$. The symbol has two vertical lines to denote the Brazilian real. The distributor was probably Casa Rosenhain, an importer operated by a German firm, Schmidt & Company, and located adjacent to the Rua São Bento park in São Paulo in the early 20th century. The donor, Sebastian J. Tralongo (1928–2007), served in the U.S. Navy during World War II and then worked for the Vitro Corporation in Rockville, Md., for 35 years. He patented a device for signaling from deeply submerged submarines and assigned the rights to Vitro. He did not report how he came to own a planimeter sold in Brazil.

- This instrument is in the design invented by Jacob Amsler (1823–1912) and made by the workshop he founded in Switzerland. The material, rounded hinge, and presence of a registering dial indicate this is a Type 2 of the six versions manufactured by Amsler.(Around 1910 Amsler's firm added a registering dial to the Type 1, but began to make that version from brass instead of German silver.) The serial number and the signature, which the firm began to use after Amsler's death, indicate that this planimeter is significantly younger than MA*318485. Unlike that instrument, the arms on this object are equal in length. Planimeter expert Joachim Fischer dated this object to about 1925. For more information on Amsler, see 1987.0107.10.

- References: "Enemy Trading List Issued by the War Trade Board,"
*Official [U.S.] Bulletin*1, no. 176 (December 5, 1917): 11; "Tralongo, Sebastian James 'Subby',"*Hartford Courant*, May 26, 2007; Sebastian J. Tralongo, "Submarine Signal Device" (U.S. Patent 2,989,024 issued June 20, 1961); "Vitro Corp. – Company Profile," http://www.referenceforbusiness.com/history2/25/Vitro-Corp.html; Crosby Steam Gage & Valve Co. Catalogue (Boston, 1888), 104–109; Joachim Fischer to Peggy A. Kidwell, October 19, 1992, Mathematics Collection files, National Museum of American History.

- Location
- Currently not on view

- date made
- ca 1925

- maker
- Amsler, Jacob

- ID Number
- 1984.1071.01

- accession number
- 1984.1071

- catalog number
- 1984.1071.01

- Data Source
- National Museum of American History, Kenneth E. Behring Center

## Keuffel & Esser 4220 Amsler Style Polar Planimeter

- Description
- This tarnished German silver instrument has two arms pivoted at one end. One arm has a tracer point and index marks for four ratios: 1 square D. (centimeters or meters, perhaps), 15 square inches, 10 square inches, and 10 square chains. A screw assembly adjusts the length of the tracer arm. A support for the tracer point prevents it from tearing the paper. Two numbers are stamped underneath the arm: 31, which appears to overstamp the number 33, and 690.

- The other arm is jointed. A cylindrical weight may be placed in the end of that arm. Underneath the weight is marked: 35. The jointed part of the arm is marked: KEUFFEL & ESSER C
__o__N.Y. Underneath the arm is stamped: 31. A carriage at the pivot holds a white plastic measuring wheel with vernier and a horizontal metal registering dial.

- A mahogany case has dark blue velvet lining the supports. A leather pouch holds the weight. A paper chart for adjusting the tracer arm is held in the lid by black plastic edges and brass screws. The columns are labeled: Proportion, Adjustement [
*sic*] on tracer-arm, and Value of unit of the Vernier. "Sq. units" is handwritten above the first entry in the Proportion column (1:1,000). The vernier entry for proportion 1:4,000 has been changed from 100 to 160 square meters.

- Keuffel & Esser sold this planimeter as model 1102 from 1892 to 1901 and as model 4220 from 1901 to 1936. It sold for $28.00 in 1909 and for $45.50 in 1936. The serial number, 690, and lack of rectangular support for the joint in the weighted arm suggest that this example was made later than 1981.0348.01. Wesleyan University donated this planimeter to the Museum in 1984–1985 with a large collection of plaster and string mathematical models purchased in 1895 from the Darmstadt, Germany, firm of L. Brill.

- References:
*Catalogue of Keuffel & Esser*, 33rd ed. (New York, 1909), 319;*Catalogue of Keuffel & Esser*, 38th ed. (New York, 1936), 336; Clark McCoy, "Collection of Pages from K&E Catalogs for the 4220 Family of Polar Planimeters," http://www.mccoys-kecatalogs.com/PlanimeterModels/ke4220family.htm.

- Location
- Currently not on view

- date made
- 1901-1936

- distributor
- Keuffel & Esser Co.

- maker
- Keuffel & Esser Co.

- ID Number
- 1985.0112.218

- catalog number
- 1985.0112.218

- accession number
- 1985.0112

- Data Source
- National Museum of American History, Kenneth E. Behring Center

## Amsler Type 3 Polar Planimeter

- Description
- This brass instrument has a 6" pole arm, an adjustable 9" tracer arm, and white plastic measuring wheel, vernier, and registering dial. The tracer arm is marked for the positions: 21,070; 21,097; 21,320; 22,884. Underneath the pole arm is marked: 19. Underneath the tracer arm is marked a serial number: N
__o__46952. An unvarnished wooden case also holds a cylindrical pole weight, a metal test plate (presumably not original to the instrument), and a brass test plate marked: 83.2 [square] cm.

- In 1854 Jacob Amsler, a Swiss teacher and mathematician, devised a planimeter that did not need the cones or wheel-and-disc constructions of earlier instruments, such as 1983.0474.02 and 1986.0633.01. His smaller and simpler device also used polar coordinates rather than the Cartesian coordinate system. The workshop he established in Schaffhausen, Switzerland, ultimately manufactured nine forms of polar planimeters.

- This example is a Type 3. The date is based on the serial number, compared to serial numbers on other Amsler planimeters in the collection. For instructions, see 1986.0316.09; 1999.0250.02 is an English translation of this leaflet. In 1907 the Crosby Steam Gage & Valve Co. of Boston sold the Amsler Type 3 planimeter for $30.00.

- 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; Michael S. Mahoney, "Amsler (later Amsler-Laffon), Jakob," in*Dictionary of Scientific Biography*, ed. Charles Coulston Gillispie (New York: Scribner, 1970),

- Location
- Currently not on view

- date made
- 1910s

- maker
- Amsler, Jacob

- ID Number
- 1986.0316.05

- accession number
- 1986.0316

- catalog number
- 1986.0316.05

- Data Source
- National Museum of American History, Kenneth E. Behring Center

## Wichmann 1192 Compensating Polar Planimeter

- Description
- This German silver and bronzed brass instrument has an 8" fixed-length pole arm with attached cylindrical weight. The arm is marked in script: Wichmann. An adjustable 9-1/2" tracer arm has a support for the tracer point and is evenly divided by tenths numbered from 5 to 36. The interval for each whole number is 5 mm long. A carriage on the tracer arm has a vernier for the scale on the tracer arm and white plastic measuring wheel, vernier, and registering dial. The carriage is marked with a serial number: 17728. A rectangular German silver test plate is marked for 2, 4, and 6 cm.

- A wooden case is covered with black leather and lined with green felt. The top of the case is marked: 1192 Gebr. Wichmann. A loose screw is inside the case. Gebrüder Wichmann (Wichmann Brothers) has sold scientific instruments and office equipment in Berlin since 1873. According to Joachim Fischer, planimeters sold by Wichmann before the 1920s were made by Coradi. Around that time, Wichmann purchased the company founded by Robert Reiss, which thenceforth supplied many of the planimeters sold by Wichmann. It is likely that this example is a Coradi instrument. For a slide rule sold by Wichmann, see MA*293320.2820.

- References: Joachim Fischer to Peggy A. Kidwell, October 19, 1992, Mathematics Collection files, National Museum of American History; A. Brachner, "German Nineteenth-Century Scientific Instrument Makers," in
*Nineteenth-Century Scientific Instruments and Their Makers*, ed. P. R. de Clercq (Amsterdam: Rodopi B. V., 1985), 152; G. Coradi,*Catalog d'orientation, No. 37*(Zurich, n.d.), 3, in accession file 2011.0043.

- Location
- Currently not on view

- date made
- ca 1930

- maker
- Gebr. Wichmann

- ID Number
- 1986.0316.06

- catalog number
- 1986.0316.06

- accession number
- 1986.0316

- Data Source
- National Museum of American History, Kenneth E. Behring Center

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