In general appearance it is a cross between the Bleriot and the Antoinette, the wings being shaped more like the latter, but rounded at the rear of the tips like the Bleriot. Its chief peculiarity is in the body of the machine, which is in form very similar to a racing shell--of course with alterations to suit the requirements of the aeroplane. Its forward part is of thin mahogany, fastened upon ash ribs, with a steel plate covering the prow. The rear part of the machine is covered simply with fabric. The spread of the plane is 24 feet 7 inches, and it has an area of 170 square feet. The length of the machine, fore-and-aft, is 23 feet. Its weight is 463 pounds. It is mounted on a chassis having both wheels and skids, somewhat like that of the Farman running gear, but with two wheels instead of four. The Hanriot machine is sturdily built all the way through, and has endured without damage some serious falls and collisions which would have wrecked another machine. It is fitted either with a Darracq or a Clerget motor, and speeds at about 44 miles per hour. THE PFITZNER MONOPLANE. The Pfitzner monoplane has the distinction of being the first American machine of the single-plane type. It was designed and flown by the late Lieut. A. L. Pfitzner, and, though meeting with many mishaps, has proved itself worthy of notice by its performances, through making use of an entirely new device for lateral stability. This is the sliding wing tip, by which the wing that tends to fall from its proper level may be lengthened by 15 inches, the other wing being shortened as much at the same time. There is no longitudinal structure, as in the other monoplanes, the construction being transverse and built upon four masts set in the form of a square, 6 feet apart, about the centre. These are braced by diagonal struts, and tied with wires on the edges of the squares. They also support the guys reaching out to the tips of the wings. [Illustration: The Pfitzner monoplane from the rear, showing the sliding wing tips; dihedral angle of the wings; square body; and transverse trussed construction.] The plane proper is 31 feet in spread, to which the wing tips add 2½ feet, and is 6 feet deep, giving a total area of 200 square feet. A light framework extending 10 feet in the rear carries a tail-plane 6 feet in spread and 2 feet in depth. Both the elevator and the rudder planes are carried on a similar framework, 14 feet in front of the main plane. [Illustration: The Pfitzner monoplane, showing the structure of the body; the two conical gasoline tanks above; the propeller in the rear. Lieutenant Pfitzner at the wheel.] The wings of the main plane incline upward from the centre toward the tips, and are trussed by vertical struts and diagonal ties. The motor is placed in the rear of the plane, instead of in front, as in all other monoplanes. It is a 4-cylinder Curtiss motor, turning a 6-foot propeller at 1,200 revolutions per minute, and developing 25 horse-power.