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Found 3,273 Resources

contra angle

National Museum of American History

Case, Computer, Preset Bomb Dropping Angles, Bombs, Felsenthal

National Air and Space Museum
Light olive cloth rectangular case for two slides.

Measuring Angles of Microscopic Crystals with the Goniometer

Smithsonian Institution Archives
Also known as MNH-11010A

See also Record Unit 95, Box 8, Folder 36.

William F. Foshag (1894-1956), working in the lab, is using a two-circle goniometer to determine the angular relations between the faces of a crystal.

angle attachment

National Museum of American History

Geometric Model by A. Harry Wheeler, Supplementary Trihedral Angles

National Museum of American History
This model consistw of six pieces of wire, each bent at the center into a ninety degree angle. The edges of the wires are held together in pairs. One leg of each wire is covered with red tubing and the other with gold tubing - the bends all meet at a central vertex. The trihedral angle bounded by the red sides is the supplement of the trihedral angle bounded by the gold sides. A paper tag with the model reads: 351.

Compare MA.304723.135 and MA.304723.136.

Geometric Model by A. Harry Wheeler, Supplementary Trihedral Angles

National Museum of American History
Three planes that meet at the center of a sphere form what is called a trihedral (three-sided) angle. Each plane intersects the sphere in a great circle. Segments of these three circles form a spherical triangle on the sphere. In this cut and folded tan paper model, Wheeler labels the vertices of this triangle ABC. Consider a point (not named by Wheeler – call it X) inside the bounds of the trihedral angle and drop perpendiculars to the three sides of the trihedral angle through it. Wheeler calls the points of intersection D, E, and F. The trihedral angle centered at X is the supplement of the original trihedral angle. Reference: D. A. Low, Practical Geometry and Graphics, New York: Longmans, Green and Co., 1912, pp. 233-235.

handpiece, right angle

National Museum of American History

handpiece, right angle

National Museum of American History

handpiece, right angle

National Museum of American History

Geometric Model by A. Harry Wheeler, Supplementary Trihedral Angles

National Museum of American History
This model consistw of six pieces of wire, each bent at the center into a ninety degree angle. The edges of the wires are held together in pairs, with all the bends meeting at the center. All the wires have tan string wound them. . One leg of each wire also is wound with gold string. The trihedral angle bounded by the plain string sides is the supplement of the trihedral angle bounded by the sides with gold thread as well.

Compare MA.304723.135 and MA.304723.136.

Sketch of a horse's head from two different angles

Archives of American Art
Drawing : 1 sheet : graphite ; 28 x 19 cm.

Geometric Model by A. Harry Wheeler, Supplementary Trihedral Angles

National Museum of American History
One adjustable tan paper spherical triangle is within a second one, both being on the same sphere. A pattern for this model indicates that it is a model for supplementary trihedral angles. The pattern is dated August 6, 1945, hence the date assigned to the model.

See 1979.3002.056.

Geometric Model by A. Harry Wheeler, Symmetrical Trihedral Angles

National Museum of American History
This a tan paper model shows two triangles facing opposite directions. The opposite trihedral angles are symmetrical.

A tag on the model reads: STA*. Another mark reads: Pat 1, 192, 483.

For related documentation, see 1979.3002.056.

Geometric Model by A. Harry Wheeler, Two Supplemetary Trihedral Angles

National Museum of American History
This wire model has three pieces bent into an L-shape and linked at the bends. The ends of the wires are also bent to hold strings. A paper tag with the model reads: 353.

Geometric Model by A. Harry Wheeler, Two Trihedral Angles

National Museum of American History
In this plastic model, a transparent tetrahedron has isosceles triangles for side faces. Inside it is a white triangle with one edge on the base and two on other faces. A paper tag on the model reads: 2TRIA. Another tag reads: A. Harry Wheeler. George Wentworth used two such figures in a theorem defining two equal trihedral angles in terms of the face angles on the faces surrounding the trihedral angle. For a related pattern, dated February 2, 1945, see 1979.0102.109. Compare 1979.0102.206 and 1979.0102.207. Reference: George A. Wentworth (with David Eugene Smith), Plane and Solid Geometry, Boston: Ginn and Company, 1913, pp. 312-313.

Geometrical Model of A. Harry Wheeler, Supplementary Trihedral Angles

National Museum of American History
This tan cut and folded paper model shows two adjustable triangles facing opposite directions. The opposite trihedral angles are symmetrical.

A paper tag on the model reads: STRIA (2). Another tag reads: Pat (/) 1192483.

Part of thetab on lower triangle is torn off.

handpiece, right angle

National Museum of American History

handpiece, contra angle

National Museum of American History

Variable Angle Prism

National Museum of American History
This container has brass sides and glass ends, and is supported on a brass stand. When filled with different liquids, it shows that they refract light in different ways. When the glass ends are set to different angles, it shows that the angle of deviation increases with the refracting angle of the prism. The “J. Duboscq / à Paris” inscription is that of the optical instrument maker, Jules Duboscq (1816-1886).

Variable Angle Prism

National Museum of American History
This container with brass sides and glass ends, supported on a brass stand, shows that different liquids refract light in different ways. When the glass ends are set to different angles, it shows that the angle of deviation increases with the refracting angle of the prism. This was purchased for the U.S. Military Academy in 1829. The “Cauchoix à Paris” inscription refers to the instrument maker, Robert-Aglae Cauchoix (1776-1845).

gauge block, angle

National Museum of American History

gauge block, angle

National Museum of American History

gauge block, angle

National Museum of American History
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