An illustration of four various axes: "1, Horseman's hammer of about the time of Edward IV; 2, Martel-de-fer,…

Conjugate diameters perpendicular to each other are called, axes, and the points where they cut the…

"...take any three edges formed by the intersection of three faces of a crystal. These axes are called…

"Science has succeeded in classifying the thousands of known crystals in six systems, to each of which…

Diagram showing how to construct an ellipse when given the two foci and the length of the major axis…

An illustration of 2 ellipses that have the equal vertical axes, but different horizontal axes. The…

An illustration of 2 ellipses that have the equal vertical axes, but different horizontal axes. The…

An illustration of 3 concentric ellipses that are tangent at the end points of the vertical axes. The…

An illustration of 3 concentric ellipses that are tangent at the end points of the vertical axes, which…

An illustration of 3 concentric ellipses that are tangent at the end points of the vertical axes. The…

An illustration of 4 concentric ellipses that are tangent at the end points of the vertical axes. The…

An illustration of 4 concentric ellipses that are tangent at the end points of the vertical axes. The…

An illustration of 4 concentric ellipses that are tangent at the end points of the vertical axes, which…

An illustration of 5 concentric ellipses that are tangent at the end points of the vertical axes. The…

An illustration of 5 concentric ellipses that are tangent at the end points of the vertical axes, which…

An illustration of 6 concentric ellipses that are tangent at the end points of the vertical axes. The…

An illustration of 6 concentric ellipses that are tangent at the end points of the vertical axes, which…

"Science has succeeded in classifying the thousands of known crystals in six systems, to each of which…

"Science has succeeded in classifying the thousands of known crystals in six systems, to each of which…

Diagram showing how to construct a hyperbola when given the two foci and the length of the major axis…

"Prisims with edges parallel to neither of the axes OX and OY...are usually called hemi-pyramids." -The…

Illustration used to show how to draw an egg-shaped oval when given the diameters.

"Crystal faces are described according to their relations to the crystallographic axes. A series of…

"Crystal faces are described according to their relations to the crystallographic axes. A series of…

"The symmetry of the Pyritohedral class is as follows: The three crystal axes of binary symmetry; the…

Stone and horn ax and hammer. A Neolithic age implement. Not drawn to scale.

"The symmetry of this class is as follows: The three crystallographic axes are axes of binary symmetry;…

"Umbel is formed when the secondary axes originate from the same point on the stem, and rise to nearly…