Subsequently this bold inventor built Eole No. 2, which, by special permission of the War Department, he tested on a prepared track, 2,400 feet long, on the Satory Camp. Over this course he ran his machine several times, and on one occasion flew 300 feet; but on alighting broke one of the wings.

Ader, now having spent one and a half million francs on his experiments, placed the Eole on exhibition in order to raise money for their continuation. In this venture also he was successful, being presently subventioned by the French War Department to build an aëroplane for its use. His subsequent labors are concisely set forth in Automobilia and Flight for February, 1909, as follows:

“Under these new conditions the workshop in the Rue Pajou was abandoned for larger premises in the Rue Jasmin, where the construction of the Avion was commenced in May, 1892, all persons engaged with the construction being under a military vow of secrecy. The motor was built first, and tested before a commission composed of army officers and some of the leading technicians of France. It was found to develop 30 horse power for a total weight of 32 kilogrammes; and even now, though seventeen years old, is regarded as a chef d’œuvre. In the spring of 1897 the Avion was ready to make flights. Like its predecessors it was modeled on the form of a bat; but, although the wings could not be flapped, they could be folded, and could be advanced or retarded horizontally.

“Everything appearing satisfactory, Ader informed the military commission that he was ready to undergo tests; the committee met at the workshops in the Rue Jasmin on August 18, 1897; were pleased with the machine, and ordered flights to be made immediately at Satory. It was not, however, until October 12th that a flight was attempted on the carefully guarded military ground, and in the presence of General Mesnier. The apparatus covered a distance of 1,600 yards, and although it did not fly, for this distance it is certain that on several occasions it completely left the ground. Ader declared that according to whether the wings were carried forward or to the rear, it was the front or the rear wheels only which left the ground. The pressure in the generator at this moment varied between 3 and 4 atmospheres. On increasing it to 6 or 7 atmospheres none of the wheels touched.

“Satisfied with the results of the test, General Mesnier called the commission together for further trials on the following day, October 14, 1897. Unfortunately it was a rough, squally morning, that would have prevented many a modern aviator from bringing a machine into the open. But as the officers had been brought together specially for this purpose, a flight was attempted.

“‘After several revolutions of the propellers, and a few yards covered at a moderate speed, we were off at a high rate of travel,’ wrote Ader, who was at the wheel on this memorable occasion. ‘The pressure was about 7 atmospheres. Almost immediately the vibrations of the rear wheel ceased, and, directly after, those of the front wheels were no longer felt, showing that we had entirely left the ground. Unfortunately the wind had increased in strength, and I had some difficulty in keeping to the line that had been marked out. I increased the pressure to 9 atmospheres, and immediately the speed increased considerably, the vibrations ceased again, showing that we had once more left the ground. Under the influence of the wind the aëroplane had a constant tendency to drift to the right, away from the circular track that had been marked for it. Finally, with the wind broadside on, the machine was in a rather dangerous position, for it was being still more rapidly driven out of its course. I increased the pressure still more and put the rudder hard over to the left, with the result that for a few seconds the machine worked back towards the track and still maintained itself in the air. But it was impossible to struggle against the wind, and finding that the machine was being carried towards some artillery sheds, and somewhat unnerved by the speed at which the ground appeared to be rushing past, I stopped the engine; there was a shock, and I was on the ground.’

“Ader was uninjured, but his machine was rather badly smashed. It had certainly flown, but with such difficulty in the face of the wind that the army commission was evidently little inclined to report favorably upon it. Several weeks passed without any communication being received from the War Department; then it became apparent to Ader that the Government had no longer faith in his invention. This was proved early in the following year by an official communication to the effect that no further funds could be allotted to this work. Discouraged at the abandonment after forty years’ labor and the expenditure of about two million francs, Ader commenced the destruction of his machines. The earlier ones were destroyed, but the Avion, the one which had appeared before the army commission, was saved and sent to the Museum of the Arts et Métiers in Paris.”

The last aëroplane, or Avion, weighed 1,100 pounds, spread 270 square feet, and was driven by a 40-horse-power steam engine actuating twin screws projecting before the bird-shaped flyer. The engine weighed but 7 pounds per horse power—quite a remarkable achievement for that day.

In following the votaries of passive flight, as represented by Lilienthal and his school, we have overlooked the great dynamic aëroplane of Mr. Maxim, one of the most prominent aëroplane builders of that active period. Having in 1889 made elaborate experiments on the atmospheric resistance of sustaining surfaces, and on the thrust of screw propellers, he proceeded to build the gigantic aëroplane shown in [Plate XVIII], the greatest flyer thus far known to history. It was a twin-screw multiplane mounted on a platform forty feet long by eight feet wide, and having four wheels running along a track eight feet wide and half a mile long. Above the rails of this track were guard rails to prevent the flyer from rising more than three inches during the tests. The whole machine weighed 3.5 tons, spread 5,500 square feet of surface, and, at a speed of 40 miles an hour, lifted more than a ton, in addition to the weight of the three men and 600 pounds of water. Its propelling plant comprised a naphtha tubular boiler, and a compound steam engine of 350 horse power actuating twin screws 17 feet 10 inches in diameter which gave a thrust approximating 2,000 pounds. These screws were made of American yellow pine, covered with canvas and painted, then smoothly sandpapered to reduce the friction; for Maxim, like certain French aviators, erroneously imagined that a polished surface has less air friction than a dead even surface. The framework was composed of seamless steel tubing stayed with steel wire. The aëroplane was to be steered right and left by a rudder, and up and down by horizontal planes, one fore, another aft, and its lateral stability was to be secured by side planes set at a dihedral angle. A meritorious feature for that day were the superposed arched surfaces whose framing was smoothly covered below and above by skillfully stretched fabric, causing the air to flow evenly without wasteful eddies.

PLATE XVIII.

MAXIM’S AËROPLANE.

(Courtesy W. J. Hammer.)