In general, we may note some of the peculiarities of _La Demoiselle_. The spread of the plane is 18 feet from tip to tip, and it is 20 feet over all from bow to stern. In height, it is about 4 feet 2 inches when the propeller blades are in a horizontal position. The total weight of the machine is 265 lbs., of which the engine weighs about 66 lbs. The area of the plane is 115 square feet, so that the total weight supported by each square foot with Santos-Dumont (weighing 110 lbs.) on board is a trifle over 3 lbs. The frame of the body of the monoplane is largely of bamboo, the three main poles being 2 inches in diameter at the front, and tapering to about 1 inch at the rear. They are jointed with brass sockets just back of the plane, for convenience of taking apart for transportation. Two of these poles extend from the axle of the wheels backward and slightly upward to the rudder-post. The third extends from the middle of the plane between the wings, backward and downward to the rudder-post. In cross-section the three form a triangle with the apex at the top. These bamboo poles are braced about every 2 feet with struts of steel tubing of oval section, and the panels so formed are tied by diagonals of piano wire fitted with turn-buckles to draw them taut. [Illustration: Side view of the Santos-Dumont monoplane. _MP_, main plane with radiator, _R_, hung underneath; _RP_, rudder plane worked by wires _HC_, attached to lever _L_; _VC_, vertical control wires; _WT_, tube through which run the warping wires worked by lever _K_, in a pocket of the pilot’s coat; _B_, _B_, bamboo poles of frame; _S_, _S_, brass, or aluminum sockets; _D_, _D_, struts of bicycle tubing; _G_, gasoline; _RG_, reserve gasoline; _M_, motor; _P_, propeller; _Q_, _Q_, outer rib of plane, showing camber; _N_, skid.] In the Santos-Dumont machine a 2-cylinder, opposed Darracq motor of 30 horse-power was used. It is of the water-cooled type, the cooling radiator being a gridiron of very thin ⅛-inch copper tubing, and hung up on the under side of the plane on either side of the engine. The cylinders have a bore of about 4⅛ inches, and a stroke of about 4¾ inches. The propeller is 2-bladed, 6½ feet across, and is run at 1,400 revolutions per minute, at which speed it exerts a pull of 242 lbs. Each wing of the main plane is built upon 2 transverse spars extending outward from the upper bamboo pole, starting at a slight angle upward and bending downward nearly to the horizontal as they approach the outer extremities. These spars are of ash, 2 inches wide, and tapering in thickness from 1⅛ inches at the central bamboo to about ⅞ inch at the tips of the wings. They are bent into shape by immersion in hot water, and straining them around blocks nailed to the floor of the workshop, in the form shown at QQ, p. 177. [Illustration: