Flexure. The capacity to bend and yield, and return to its original position.

Flexible, That which will yield; springy.

Fore and Aft. Lengthwise, as from stem to stern of a ship.

Formation. The shape or arrangement of an article or thing.

Formulated. Put into some eonerete form, or so arranged that it may be understood.

Frictionless. Being without a grinding or retarding aotion.

Fulcrumed. A resting place for a lever.

Function. The duty or sphere of action in a person, or object.

Glider. An aeroplane, without power, adapted to be operated by an aviator.

Governing. An element which is designed to control a machine in a regular manner.