Magnetic compass with pendulum clinometer, sights, and map distance meter that resembles the geological compass with clinometer sold by F. W. Breithaupt und Sohn of Kassel, Germany. According to the donor, this compass belonged to her father, Peter Moses. He served in the U.S. Army in Germany during World War II, and presumably acquired this instrument at that time.
The DKM2 is a double-circle theodolite with an optical micrometer. Heinrich Wild developed the form for Kern in the 1930s. Like the T2 manufactured by Wild in Heerbrugg, the DKM2 is a lightweight instrument with a steel frame. The horizontal and vertical circles are glass, and read directly to single seconds. The telescope is equipped with stadia wires, and so can be used for tachymetry. An auxiliary eyepiece lying alongside the telescope allows the user to read either circle without moving away from the station. Here, however, the two scales are read through the optical micrometer with reference to a centrally located index, giving the arithmetic mean of two diametrically opposed points on the circle. In 1955, an instrument of this sort, with tripod, cost $1,221. This example is marked "Kern AARAU SUISSE SWITZERLAND No 37845 DKM2." It was purchased in 1963, and given to the Smithsonian in 1997.
Ref: Kern & Co., Ltd, Double Circle Theodolites (about 1959).
Aluminum resonance bar suspended over a square wood resonator suitable for acoustic demonstrations. This was made by Carl J. Ulrich (1873-1955), a German immigrant who moved to Minneapolis in 1924, taught physics at Roosevelt High School, and made science teaching apparatus.
This sextant was made for emergency use during World War II. The body is plastic. The scale is graduated every degree from -5° to +140° and read by vernier to 3 minutes of arc. The box is marked "U.S. MARITIME COMMISSION / CRUVER MFG. CO." The Cruver Manufacturing Co., in Chicago, began making novelty objects of plastic in the early 1900s. The U.S. Maritime Commission (fl. 1936 to 1950) was responsible for further developing and maintaining a merchant marine for the promotion of American commerce and defense.
Ref: W. J. Eckert, Lifeboat Sextant. Instructions for Use in Finding Latitude and Longitude Together with Simple Sailing Instructions (U.S. Naval Observatory, 1944).
This type of sextant was introduced during World War II. The limb is graduated to single degrees. A drum micrometer, the teeth of which mesh with teeth cut into the edge of the limb, reads to 1 minute and, with vernier, to 6 seconds of arc. The inscriptions read "David White Co. Milwaukee, Wis." and "U.S. NAVY, BU. NAV. MARK II"
Ref: Benjamin Dutton, Navigation and Nautical Astronomy (Annapolis, Md., 1948), pp. 347-355.
Photograph of a ½ Moon glued to a glass plate. A handwritten paper label reads “July 11th 1873 1 ½ am [']s fog.” This was taken by Henry Draper (1837-1882), an American physician who did important early work in astrophotography, much of it in the observatory he established on his father’s estate at Hastings-on-Hudson, New York.
Ref: George Frederick Barker, Biographical Memoir of Henry Draper (1888).
Glass positive photograph of a total solar eclipse. The inscription on the original envelope read "Lick Observatory, University of California, Total Solar Eclipse of 1898 Jan 22 Exposure 2s. taken at Jeur, India by the Crocker Expedition."
Range finder with a "STADIMETER U.S. NAVY BUREAU OF ORDNANCE MARK III MOD. 1 NO. 409 / 1918 INSPEC. CHD MADE BY KEUFFEL & ESSER CO. NEW YORK" inscriptions. Unlike the other examples in the collection, this one has a telescopic sight. It was made during World War I. The form was developed in the 1890s by the innovative American naval officer, Bradley Allen Fiske (1854-1942).
Ref: Instructions for the Use and Care of the Fiske Ship-Telegraphs and Stadimeter (Published by Authority of the Bureau of Ordnance, Navy Department, 1896).
Paolo E. Coletta, Admiral Bradley A. Fiske and the American Navy (Lawrence: University of Kansas Press, 1979), pp. 38-40.
This simple surveying instrument offered minimal precision at an affordable price. Its horizontal circle is graduated to single degrees. William Rutter, a farmer and builder in Prince George's County, Md., acquired it in the 1920s.
Aluminum resonance bar suspended over a cylindrical aluminum resonator suitable for acoustic demonstrations. This was made by Carl J. Ulrich (1873-1955), a German immigrant who moved to Minneapolis in 1924, taught physics at Roosevelt High School, and made science teaching apparatus.
6.5" x 8.5" glass plate positive image of the moon taken at the Yerkes Observatory. A paper label reads "Mare Serenitatis and Mare Tranquilitatis. Photo with the 40-inch visual telescope, Yerkes Obs'y, with color screen and isochromatic plate. August 3rd 1901 G.W. Ritchey."
A spherometer is used primarily to measure the curvature of objects such as lenses and curved mirrors. This rather large example belonged to Bowdoin College. It has no markings but most likely was purchased from an educational instrument maker in the 19th century. It is accompanied by an optical flat used to zero the device. It has both a vertical scale and horizontal scale on the disc. To improve accuracy, a magnifying lever is mounted on the top of the micrometer disc. The two small arms would have pointed to a secondary scale that arched over the top of the device but is now missing.
Bausch & Lomb began making refractometers when World War I limited the import of European instruments coming into the United States. The inscription on this Abbé-type refractometer reads "Bausch & Lomb Optical Company Rochester N.Y. Ser. No. 77381 USA Pat. No. 2,080,841." The referenced patent, issued to Harold Straat in 1937 and assigned to Bausch & Lomb, described a new prism system and box for refractometers.
Ref: Richard A. Paselk, “The Evolution of the Abbé Refractometer,” Bulletin of the Scientific Instrument Society 62 (1999): 19-22.