The newest biplane of the Aerial Experiment Association follows in general contour its successful precursor, the “Silver Dart,” with which J. A. D. McCurdy made many records. The “Baddeck No. 2” is of the biplane type, and both the planes are arched toward each other. They have a spread of 40 feet, and are 7 feet in depth at the centre, rounding to 5 feet at the ends, where the wing tips, 5 feet by 5 feet, are hinged. The elevator is also of the biplane type, two surfaces each 12 feet long and 28 inches wide, set 30 inches apart. This is mounted 15 feet in front of the main planes. The tail is mounted 11 feet in the rear of the main planes, and is the same size and of the same form as the elevator. The controls are operated by the same devices as in the Curtiss machine. The propeller is 7 feet 8 inches in diameter, and is turned by a six-cylinder automobile engine of 40 horse-power running at 1,400 revolutions per minute. The propeller is geared down to run at 850 revolutions per minute. The motor is placed low down on the lower plane, but the propeller shaft is raised to a position as nearly as possible that of the centre of resistance of the machine. The speed attained is 40 miles per hour. [Illustration: The McCurdy biplane, “Baddeck No. 2.”] A unique feature of the mechanism is the radiator, which is built of 30 flattened tubes 7 feet 6 inches long, and 3 inches wide, and very thin. They are curved from front to rear like the main planes, and give sufficient lift to sustain their own weight and that of the water carried for cooling the cylinders. The running gear is of three wheels placed as in the Curtiss machine. The “Baddeck No. 2” has made many satisfactory flights with one passenger besides the pilot. THE HERRING BIPLANE. At the Boston Aircraft Exhibition in February, 1910, the Herring biplane attracted much attention, not only because of its superiority of mechanical finish, but also on account of its six triangular stabilizing fins set upright on the upper plane. Subsequent trials proved that this machine was quite out of the ordinary in action. It rose into the air after a run of but 85 feet, and at a speed of only 22 miles per hour, and made a 40-degree turn at a tipping angle of 20 degrees. As measured by the inventor, the machine rose in the air with the pilot (weighing 190 lbs.), with a thrust of 140 lbs., and required only a thrust of from 80 to 85 lbs. to keep it flying. The spread of the planes is 28 feet, and they are 4 feet in depth, with a total supporting surface of 220 feet. A 25 horse-power Curtiss motor turns a 4-bladed propeller of 6 feet diameter and 5-foot pitch (designed by Mr. Herring) at the rate of 1,200 revolutions per minute. [Illustration: The L. A. W. (League of American Wheelmen) biplane at the Boston Aircraft Exhibition, February, 1910. Note the peculiar curve of the divided planes. The motor is of the rotating type, of 50 horse-power.]