ClipArt ETC
Illustration of two intersecting spheres. "The intersection of two spherical surfaces is the circumference of a circle whose plane is perpendicular to the line joining the centres of the surfaces and whose centre is in that line."

Intersecting Spheres

Illustration of two intersecting spheres. "The intersection of two spherical surfaces is the circumference…

Diagram used to prove the theorem: "A spherical angle is measured by the arc of a great circle described from its vertex as a ole and included between its sides (produced if necessary)."

Measure of a Spherical Angle

Diagram used to prove the theorem: "A spherical angle is measured by the arc of a great circle described…

An illustration of a flanged spherical segment with a diameter of 10 inches. Illustration could be used to find the area.

Flanged Spherical Segment

An illustration of a flanged spherical segment with a diameter of 10 inches. Illustration could be used…

Diagram used to prove the theorem: "The volume of a spherical segment is equal to the sum of two cylinders and a sphere, the altitudes of the cylinders being one half the altitude of the segment, and their bases the upper and lower bases of the segment, respectively, and the diameter of the sphere being the altitude of the segment."

Volume of Spherical Segment

Diagram used to prove the theorem: "The volume of a spherical segment is equal to the sum of two cylinders…

Diagram used to prove the theorem: "In a spherical triangle, the greater side is opposite the greater angle, and conversely."

Side Comparison of Spherical Triangle

Diagram used to prove the theorem: "In a spherical triangle, the greater side is opposite the greater…

Diagram showing 2 superimposed symmetrical spherical triangles.

Superimposed Symmetrical Spherical Triangles

Diagram showing 2 superimposed symmetrical spherical triangles.

Diagram showing 2 symmetrical spherical triangles.

Symmetrical Spherical Triangles

Diagram showing 2 symmetrical spherical triangles.

"An instrument for measuring the radii of spheres; a sphere-measurer. It is of especial service to opticians in determining focal lengths, etc. of lenses. The common form consists of a vertical screwc, with a large graduated head a, a, turning in a socket supported by three legs whose hard steel points are exactly equidistant. The fixed scale b at the side, together with the graduated screwhead, makes it possible to measure with great accuracy the distance between the extremity of the screw and the plane passing through the ends of the three supports, when, for example, all the points are in contact with the surface of the sphere." —Whitney, 1889

Spherometer

"An instrument for measuring the radii of spheres; a sphere-measurer. It is of especial service to opticians…

Illustration of an isosceles spherical triangle.

Isosceles Spherical Triangle

Illustration of an isosceles spherical triangle.

Illustration of an isosceles spherical triangle.

Isosceles Spherical Triangle

Illustration of an isosceles spherical triangle.

Diagram showing a spherical triangle.

Spherical Triangle

Diagram showing a spherical triangle.

Diagram showing a spherical triangle constructed by the intersection of polar arcs.

Spherical Triangle

Diagram showing a spherical triangle constructed by the intersection of polar arcs.

Diagram showing a spherical triangle constructed by the intersection of polar arcs.

Spherical Triangle

Diagram showing a spherical triangle constructed by the intersection of polar arcs.

Diagram showing a spherical triangle constructed by the intersection of polar arcs.

Spherical Triangle

Diagram showing a spherical triangle constructed by the intersection of polar arcs.

Illustration of polar and spherical triangles.

Polar and Spherical Triangles

Illustration of polar and spherical triangles.

Illustration of polar triangles.

Polar Triangles in Sphere

Illustration of polar triangles.

Illustration of symmetrical spherical triangles.

Symmetric Spherical Triangles

Illustration of symmetrical spherical triangles.

Illustration of symmetrical spherical triangles.

Symmetric Spherical Triangles

Illustration of symmetrical spherical triangles.

Illustration of symmetrical spherical triangles.

Symmetric Spherical Triangles

Illustration of symmetrical spherical triangles.

Diagram showing a 2 symmetrical spherical triangles.

Two Symmetrical Spherical Triangles

Diagram showing a 2 symmetrical spherical triangles.