An illustration of Penaud's artificial flying bird. "a b c d, a', b' c' d', lactic wings which twist and untwist when made to vibrate; a b, a' b', Anterior margins of wings; c d, c' d', Posterior margins of wings; c, c' Inner portions of wings attached to central of model by elastic bands at e' f, India-rubber in a state of torsion, which provides the motive power, by causing the crank situated between the vertical wing supports (g) to rotate; as the crank revolves the wing are made to vibrate by means of two rods which extend between the crank and the roots of the wings; h, tail of artificial bird." -Britannica, 1910

Penaud's Artificial Flying Bird

An illustration of Penaud's artificial flying bird. "a b c d, a', b' c' d', lactic wings which twist…

An illustration of a elastic aerial screw with twisted blades. "X, End of driving shaft; v,w, Sockets in which the roots of the blades of the screw rotate, the degree of rotation being limited by steel springs (z, s); ab, ef, Tapering elastic rods forming anterior or thick margins of blades of screw; d c, h g, Posterior or thin elastic margins of blades of screw. The arrows m, n, o, p, q, r, indicate the direction of travel." -Britannica, 1910

Elastic Aerial Screw with Twisted Blades Resembling Wings

An illustration of a elastic aerial screw with twisted blades. "X, End of driving shaft; v,w, Sockets…

An illustration of an "elastic spiral wing, which twists and untwists during its action, to for a mobile helix or screw. This wing is made to vibrate by a direct piston action, and b a slight adjustment can be propelled vertically, horizontally or at any degree of obliquity." -Britannica, 1910

Elastic Spiral Wing

An illustration of an "elastic spiral wing, which twists and untwists during its action, to for a mobile…

An illustration of a double elastic spiral wing.

Double Elastic Spiral Wing

An illustration of a double elastic spiral wing.

An illustration of elastic spiral wings of the gull. "a b, Anterior margin of the left wing; c d, Posterior margin of the ditto; d g, Primary or rowing feathers of left wing; g a, Secondary feathers ditto; x, root of right wing with ball-and-socket joint; l, Elbow joint; m, Wrist joint; n o, Hand and finger joints." -Britannica, 1910

Elastic Spiral Wings of the Gull

An illustration of elastic spiral wings of the gull. "a b, Anterior margin of the left wing; c d, Posterior…

This is a toy pistol which simulates an actual pistol.

Toy Pistol

This is a toy pistol which simulates an actual pistol.