The elevator consists of a pair of parallel surfaces set upon hollow poles 12 feet in front of the main planes. The tail is a single surface. The stabilizing fins act in this manner: when the machine tips to one side, it has a tendency to slide down an incline of air toward the ground. The fins offer resistance to this sliding, retarding the upper plane, while the lower plane slides on and swings as a pendulum into equilibrium again. THE BREGUET BIPLANE. The Breguet biplane is conspicuous in having a biplane tail of so large an area as to merit for the machine the title “tandem biplane.” The main planes have a spread of 41 feet 8 inches, and an area of 500 square feet. The tail spreads 24 feet, and its area is about 280 square feet. The propeller is three-bladed, 8 feet in diameter, and revolves at a speed of 1,200 revolutions per minute. It is placed in front of the main plane, after the fashion of the monoplanes. The motive power is an 8-cylinder R-E-P engine, developing 55 horse-power. [Illustration: _Courtesy of N. Y. Sun._ The Seddon tandem biplane, constructed by Lieutenant Seddon of the British Navy. The area of its planes is 2,000 square feet. Compare its size with that of the monoplane in the background. It is intended to carry ten persons.] [Illustration: Wright biplane. Curtiss biplane. Comparative build and area of prominent American biplanes.] [Illustration: Voisin biplane. Breguet biplane. Comparative build and area of prominent European biplanes.] Chapter VI. FLYING MACHINES: THE MONOPLANE. The common goal--Interchanging features--The Bleriot machine--First independent flyer--Construction and controls--The “Antoinette”--Large area--Great stability--Santos-Dumont’s monoplane--Diminutive size--R-E-P monoplane--encased structure--Hanriot machine--Boat body--Sturdy build--Pfitzner machine--Lateral type--Thrusting propeller--Fairchild, Burlingame, Cromley, Chauviere, Vendome, and Moisant monoplanes. In all the ardent striving of the aviators to beat each other’s records, a surprisingly small amount of personal rivalry has been developed. Doubtless this is partly because their efforts to perform definite feats have been absorbing; but it must also be that these men, who know that they face a possible fall in every flight they make, realize that their competitors are as brave as themselves in the face of the same danger; and that they are actually accomplishing marvellous wonders even if they do no more than just escape disastrous failure. Certain it is that each, realizing the tremendous difficulties all must overcome, respects the others’ ability and attainments.