These experiments demonstrated most conclusively that as much as 133 lbs. could be sustained and carried by the expenditure of one horse-power, and that a screw was a fairly efficient air propeller. They also demonstrated that a well made aeroplane, placed at an angle of 1 in 14, would lift practically fourteen times the thrust required to drive it through the air, and that the skin friction on a smooth and well finished aeroplane or screw was so small as not to be considered. A large number of aeroplanes were experimented with, and it was found that those which were slightly concave on the underneath side and convex on the top, both edges being very sharp and the surface very smooth and regular, were the most efficient; also that with small screw propellers, two blades having slightly increasing pitch were the most efficient. * * * * * Since writing the foregoing, great progress has been made with flying machines, and great disasters have happened to airships or balloons. Count Zeppelin’s gigantic airship encountered a squall or thunder shower, and the work of years, which had cost over £100,000, was reduced to scrap metal in a few minutes. Similar disasters have happened to other balloons. The British Dirigible No. 2 has not attempted a long flight, but the Wright Brothers, Farman, and De la Grange have all met with a certain degree of success. A few months ago, the remarkable feats of the Wright Brothers in the States were discredited in Europe. It was claimed that “the accounts were not authentic,” “too good to be true,” etc., but recent events have shown that the Wright Brothers are able to outdo anything that was reported in the American Press. On many occasions they have remained in the air for more than an hour, and have travelled at the rate of 30 to 40 miles an hour; in fact, the remarkable success of the Wright Brothers has placed the true flying machine in a new category. It can no longer be ranked with the philosopher’s stone or with perpetual motion. Success is assured, and great and startling events may take place within the next few years. [Illustration: Fig. 92.--Count Zeppelin’s aluminium-covered airship coming out of its shed on Lake Constance.] [Illustration: Fig. 93.--Count Zeppelin’s airship in full flight.] [Illustration: Fig. 94.--The new British war balloon “Dirigible” No 2.] [Illustration: Fig. 95.--The Wright aeroplane in full flight.] GENERAL INDEX. PAGE