Projections of a Line

Projections of a line inclined to a plane.

Projections of a Line

Projections of a line inclined to both the horizontal and vertical planes will not show its true length,…

Projections of a Line

Projections of a line's true length by revolving horizontal projection.

Projections of a Line

Projections of a line's true length by revolving vertical projection.

Construction of Logarithmic Spiral

Illustration showing how a rolling logarithmic spiral can be constructed by taking successive values…

Rolling of Logarithmic Spirals

Illustration showing the rolling of two logarithmic spirals of equal obliquity.

Marcasite

"Orthorhombic. Crystals commonly tabular parallel to basal plane, showing also short prisms and low…

Plane Mirror

"Suppose the mirror, a b, to be placed on the side of a room, and a lamp to be set in antoher room,…

Plane Mirror

"Suppose the arrow a to be the object reflected b the mirror d c; the incident rays a, flowing from…

Plane Mirror

"If an object is placed before a plane mirror, a virtual image appears behind the mirror. Each point…

Plane Mirror

"A plane mirror reflects from a flat surface, like a common looking glass." —Quackenbos 1859

Multiple Images in a Plane Mirror

"By placing two plane mirrors facing each other, we may produce an indefinite series of images of an…

Object in Plane Mirror

"The construction for the image produced by a plane mirror depends upon the fact that the image of the…

Plane Inclined Mirrors

"The incident rays, a and b, being parallel before they reach the reflectors, are thrown off at unequal…

Early Design Monoplane

An airplane with a single wing

Moulding Plane

"The moulding plane." — Encyclopedia Britannica, 1893

Rolling of Non-cylindrical Surfaces

Illustration showing that the rolling of non-cylindrical surfaces. "If the angular velocity ratio of…

Frustum Of A Nonagonal Pyramid

Illustration of a hollow nonagonal pyramid that has been cut by a plane parallel to the base. The top…

Finding the North Star

"Two stars in the Big Dipper opposite the handle indicate the direction toward the North Star, which,…

Octagonal Pyramid Cut By Plane

Illustration of a right octagonal pyramid, with hidden edges shown, that has been cut by a plane parallel…

Octagonal Pyramid Cut By Plane

Illustration of a right octagonal pyramid that has been cut by a plane parallel to the base. The lower…

Frustum Of A Octagonal Pyramid

Illustration of a hollow octagonal pyramid that has been cut by a plane parallel to the base. The top…

Twinned octahedron

"A contact twin, since the two individuals lie simply in contact with each other upon a certain plane."…

Orthographic Pyramid Projection

An orthographic projection of a pyramid from three dimensional space into two dimensional space

Cone Intersected by a Plane to Form a Parabola

Diagram of a cone intersected by plane J to form a parabola. Also pictured is a circle formed by the…

Construction of a Parabola

Diagram showing how to construct a parabola when given the directrix (d), the focus (F) and the eccentricity…

Parallel Planes

To draw a plane through a given point parallel to a given plane.

Frustum Of A Pentagonal Pyramid

Illustration of a right pentagonal pyramid that has been cut by a plane parallel to the base. The top…

Frustum Of A Pentagonal Pyramid

Illustration of a hollow pentagonal pyramid that has been cut by a plane parallel to the base. The top…

Frustum Of A Pentagonal Pyramid

Illustration of a right pentagonal pyramid, with a height much larger than the edge lengths of the base,…

Frustum Of A Pentagonal Pyramid

Illustration of a right pentagonal pyramid, with a height smaller than the edge lengths of the base,…

Frustum Of A Pentagonal Pyramid

Illustration of a hollow pentagonal pyramid that has been cut by a plane parallel to the base. The top…

Frustum Of A Skewed Pentagonal Pyramid

Illustration of a skewed pentagonal pyramid that has been cut by a plane parallel to the base. The top…

Perpendicular Planes

Two planes lie perpendicular to one another. A line perpendicular to plane 1 and a line perpendicular…

Front View Pusher Aeroplane Plan

A pusher aeroplane plan illustrating the proper ribbing and wiring for the plane. The wires are used…

Propeller Aeroplane Side Plan

A propeller airplane plan illustrating the proper location of the skeleton and placement of the wires…

Propeller Aeroplane Top Plan

A top view plan of a propeller aeroplane, or airplane. The plan shows the proper ribs and skeleton for…

Propeller Aeroplane Top Plan

A side view plan of a propeller aeroplane for two people. The plan illustrates the the proper location…

Pusher Aeroplane Plan

A plan for pusher aeroplane, or airplanes. The propeller of the pusher plane is located behind the cockpit…

Plane

Illustration showing a how in "analytic geometry it is customary to specify the position of a plane…

Plane Tool

A plane is a tool for shaping wood. Planes are used to flatten, reduce the thickness of, and impart…

Inclined Plane

An inclined plane used to multiply work done.

Plane Determined by 2 Intersecting Lines

Illustration of a plane determined by 2 intersecting lines

Line Projected Upon Plane

Illustration of a straight line projected upon a plane.

Locus Point to a Plane

"The locus of a point in space equidistant from the extremities of a straight line is the plane perpendicular…

Oblique Lines Drawn to a Plane

Oblique lines drawn from a point to a plane.

Plane Determined by 2 Parallel Lines

Illustration of a plane determined by 2 parallel lines

Line Perpendicular to Plane

If a straight line is perpendicular to each of two other straight lines in a plane at their point of…

Line Perpendicular to Plane

Straight line AB is perpendicular to the lines in plane MN at point B.

Line Perpendicular to Plane

Straight line AB is perpendicular to the lines in plane MN at point B. "If from the foot of a perpendicular…

Lines Perpendicular to Plane

Two straight lines, AB and CD, perpendicular to the same plane (MN) are parallel.

Pyramid Cut By Plane

Diagram used to prove the theorem: "If a pyramid is cut by a plane parallel to the base, the edges are…

Plane Rotated About a Straight Line

Illustration of a plane rotated about a straight line.

Sphere Cut By Plane

Diagram used to prove the theorem: "Every section of a sphere by a lane is a circle."

Sphere Tangent to Plane

Diagram used to prove the theorem: "A plane perpendicular to a radius at its extremity is tangent to…

Symmetry plane

"A crystal has a center of symmetry if an imaginary line is passed from some point on its surface through…

3 Intersecting Planes

Illustration of three intersecting planes. "The intersections of two parallel planes by a third plane…

3 Intersecting Planes

Illustration of three intersecting planes. "The straight line perpendicular to one of two parallel lanes…

3 Parallel Planes

"If two straight lines are cut by three parallel planes, the corresponding segments are proportional."

Angles In Parallel Planes

"If two angles not in the same plane have their sides respectively parallel and lying in the same direction,…