### Ancient Mariner

From Coleridge's The Rime of the Ancient Mariner. An old mariner tells his tales to a young man who…

### Reindeer age articles, Bone points and needles

Bone points and bone needles. Crafted during the Reindeer age.

### Cathedral

A cathedral with pointed towers.

### 1/8 Cent

The board of trade sign for 1/8 cent.

### Center of Gravity

"The part of the body in which the centre of gravity is situated, may be found, in some cases, by balancing…

### Circle With Center o and Radius r with point P

Circle modeling the earth. O is the center of the earth, r the radius of the earth, and h the height…

### Circle With Two Tangents Drawn From an External Point

Illustration of a circle which illustrates that the tangents to a circle drawn from an external point…

### Construction of a Circle When Given Two Points and a Radius

Illustration used to construct a circle when given two points that it passes through and a radius.

### Construction of Perpendicular From a Given Point on a Straight Line

Illustration of the construction of a perpendicular to a line when given a point O on the straight line.

### Construction of Perpendicular From a Given Point on a Straight Line

Illustration of the construction of a perpendicular to a line when given a point B on the straight line.

### Coordinate Axis With Angles, Lines, and Perpendiculars Drawn

Coordinate axis with angle XOP equal to theta, Θ, and angle XOQ=180 - Θ. From any point in the terminal…

### Coordinate Axis With Perpendiculars Drawn To Form Similar Right Triangles From Positive and Negative Theta, Θ

Angle XOP=Θ and angle XOQ=- Θ. From a point in the terminal side of each a perpendicular line is drawn…

### Coordinate Axis With Perpendiculars Drawn To Form Similar Right Triangles

Angle XOP=Θ and angle XOQ=90+Θ. From a point in the terminal side of each a perpendicular line is…

### Curve in Pavement of Road

Illustration of blueprint used by highway engineers to widen the pavement on the inside of the curve…

### Dedekind Property 1

Illustration 1 of the Dedekind axiom.

### Dedekind Property 2

Illustration 2 of the Dedekind axiom.

### Dedekind Property 3

Illustration 3 of the Dedekind axiom.

### Dedekind Property 4

Illustration 4 of the Dedekind axiom.

### Point Distance

To determine the distance between two points A, B given by their projections.

### Double Arrow, Black and White

The Double Arrow sign may be used to advise road users that traffic is permitted to pass on either side…

### Double Arrow, Color

The Double Arrow sign may be used to advise road users that traffic is permitted to pass on either side…

### Double Arrow, Outline

The Double Arrow sign may be used to advise road users that traffic is permitted to pass on either side…

### Double Arrow, Silhouette

The Double Arrow sign may be used to advise road users that traffic is permitted to pass on either side…

### Driving a Car

People driving in a car arrive at their destination and read the sign.

### Ordinate and Major Axis of Ellipse

Illustration of half of an ellipse. The square of the ordinate of a point in an ellipse is to the product…

### Flashcard of a Point

A flashcard featuring an illustration of a Point

### Girl Pointing

A girl standing with her arm in front of her, pointing at something.

### Hand signal

"To add 50 yards describe a short horizontal line with forefinger." — Moss, 1914

### Auxiliary Circle and Hyperbola

Illustration of a hyperbola and its auxiliary circle. "Any ordinate of a hyperbola is to the tangent…

### Foci Distance of Hyperbola

Illustration of a hyperbola with distances to foci drawn. "The difference of the distances of any point…

### Line Bisecting Angle Between Focal Radii in Hyperbola

Illustration of a hyperbola with a line bisecting the focal radii. "If through a point P of an hyperbola…

### Point on a Hyperbola

Illustration of a point on a hyperbola. "If d denotes the abscissa (x-coordinate) of a point of an hyperbola,…

### Tangent to Hyperbola

Illustration showing how to draw a tangent to an hyperbola from a given point P on the convex side of…

### Joab's Artifice

Joab's Artifice, from Hans Holbein's series of engravings known as his Bible Cuts.

### Sagittate Leaf

A leaf shaped like a triangle.

### Lemniscate

A Lemniscate is, in general, a curve generated by a point moving so that the product of its distances…

### Lincoln Cathedral

"Sectional compartment of the Nave of Lincoln Cathedral." — Encyclopedia Britanica, 1893

### Lincoln Cathedral

"Sectional compartment of the Choir of Lincoln Cathedral." — Encyclopedia Britanica, 1893

### Line Projection

To find the projections of a line which joins two points, A, B given by their projections.

### Straight Line With Points Divided Into Equal Parts

An illustration of a straight line with 5 points dividing it into 4 equal parts. Multiple of a given…

### Straight Line With Point

An illustration of a straight line with a point.

### Intersecting Straight Lines

Illustration of two lines intersecting at a point. This can be used to show vertical angles.

### Lines Drawn From the Same Point in a Perpendicular to a Given line, Cutting Off Segments

Illustration showing two straight lines drawn from the same point in a perpendicular to a given line,…

### Lines Drawn to Another Line to Form Triangle

Illustration of two straight lines drawn from a point in a perpendicular to a given line, cutting off…

### Man Sitting & Child Standing Near Lake

An illustration of a man sitting on the shore of a lake and a child standing behind him pointing into…

### Pantograph

An instrument for making a reduced, enlarged, or exact copy of a plane figure

### Point on Parabola

Illustration of a parabola showing point P is equidistant to the focus and the directrix.

### Point on Parabola

Illustration of a parabola. "If a line PT is drawn from any point P of the curve, bisecting the angle…

### Tangent to a Parabola

Illustration of a tangent line drawn from an external point to a parabola.

### Parallel Planes

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

### Perpendicular Planes

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

### Potent Counter-Potent Shield

"Potent counter-potent, sometimes called varry cuppy, differs from potent in that the potents of the…

### Radical Center of 3 Circles

Given any three circles, the common chords meet at one point.

### Retina

"Diagrammatic section through the eyeball. xx, optic axis; k, nodal point." —Martin, 1917

### Retina

"Diagram illustrating the points at which incident rays meet the retina. xx, optic axis; k, first nodal…