"Leaf-shaped Flint Dagger." — The Encyclopedia Britannica, 1910

Dagger

"Leaf-shaped Flint Dagger." — The Encyclopedia Britannica, 1910

Flint arrow heads. A Neolithic age implement. Not drawn to scale.

Neolithic Implements Flint Arrowheads

Flint arrow heads. A Neolithic age implement. Not drawn to scale.

A flint knife, Neolithic age implement. Not drawn to scale.

Neolithic Implements Flint Knife

A flint knife, Neolithic age implement. Not drawn to scale.

"A double convex lens of crown-glass may be combined with a plano-convex lens of flint-glass so as to overcome the dispersive effect for some of the colors without overcoming the converging effect." -Avery 1895

Achromatic Lens

"A double convex lens of crown-glass may be combined with a plano-convex lens of flint-glass so as to…

"Five kinds of glass are made: flint glass, or crystal; crown glass, broad sheet glass, bottle, or green glass, and plate glass." —The Popular Cyclopedia, 1888

Glass manufacturing

"Five kinds of glass are made: flint glass, or crystal; crown glass, broad sheet glass, bottle, or green…

A revolutionary flint-lock pistol with a short, thick barrel. Requires reloaded after each shot.

Revoltionary Flint-Lock Pistol

A revolutionary flint-lock pistol with a short, thick barrel. Requires reloaded after each shot.

"Implements of the Stone Age. 1, saw-edged flint knife; 2, crescent-shaped flint knife; 3, stone ax; 4, flint flake-knife; 5, harpoon-head of flint; 6, flint knife."-Whitney, 1902

Stone Age Tools

"Implements of the Stone Age. 1, saw-edged flint knife; 2, crescent-shaped flint knife; 3, stone ax;…

"Professor Swan's Designs.—Among several ingenious arrangements and new forms of agents proposed by Professor Swan is the mode of sending rays from prisms through interstices left between other prisms placed in front, and also a form of agent which he termed the triesoptric prism, in which the rays would undergo two refractions and three reflexions. a are the front and b the triesoptric prisms. The two upper and lower prisms a are constructed of flint glass of high refractive power. It will be observed from the drawing that this ingenious arrangement is nevertheless open to objection, for cones of light of 30 degrees in front and of 65 degrees at the back are lost through the interstices." —The Encyclopedia Britannica, 1910

Swans Designs

"Professor Swan's Designs.—Among several ingenious arrangements and new forms of agents proposed…