Therefore I resolved to build an elongated balloon just large enough to raise, along with my own 50 kilogrammes (110 lbs.) of weight, as much more as might be necessary for the basket and rigging, motor, fuel, and absolutely indispensable ballast. In reality I was building an air-ship to fit my little tricycle motor.
I looked for the workshop of some small mechanic near my residence in the centre of residential Paris where I could have my plans executed under my own eyes and could apply my own hands to the task. I found such an one in the Rue du Colisée. There I first worked out a tandem of two cylinders of a tricycle motor—that is, their prolongation, one after the other, to work the same connecting-rod while fed by a single carburator.
To bring everything down to a minimum weight, I cut out from every part of the motor whatever was not strictly necessary to solidity. In this way I realised something that was interesting in those days—a 3½" horse-power motor that weighed 30 kilogrammes (66 lbs.).
I soon had an opportunity to test my tandem motor. The great series of automobile road-races, which seems to have had its climax in Paris-Madrid in 1903, was raising the power of these wonderful engines by leaps and bounds year after year. Paris-Bordeaux in 1895 was won with a 4 horse-power machine at an average speed of 25 kilometres (15½" miles) per hour. In 1896 Paris-Marseilles-and-return was accomplished at the rate of 30 kilometres (18½" miles) per hour. Now, in 1897, it was Paris-Amsterdam. Although not entered for the race it occurred to me to try my tandem motor attached to its original tricycle. I started, and to my contentment found that I could keep well up with the pace. Indeed, I might have won a good place in the finish—my vehicle was the most powerful of the lot in proportion to its weight, and the average speed of the winner was only 40 kilometres (25 miles) per hour—had I not begun to fear that the jarring of my motor in so strenuous an effort might in the long run derange it, and I imagined I had more important work for it to do.
For that matter, my automobiling experience has stood me in good stead with my air-ships. The petroleum motor is still a delicate and capricious thing, and there are sounds in its spitting rumble that are intelligible only to the long-experienced ear. Should the time come in some future flight of mine when the motor of my air-ship threatens danger I am convinced that my ear will hear, and I shall heed, the warning. This almost instinctive faculty I owe only to experience. Having broken up the tricycle for the sake of its motor I purchased at about this time an up-to-date 6 horse-power Panhard, with which I went from Paris to Nice in 54 hours—night and day, without stop—and had I not taken up dirigible ballooning I must have become a road-racing automobile enthusiast, continually exchanging one type for another, continually in search of greater speed, keeping pace with the progress of the industry, as so many others do, to the glory of French mechanics and the new Parisian sporting spirit.
But my air-ships stopped me. While experimenting I was tied down to Paris. I could take no long trips, and the petroleum automobile, with its wonderful facility for finding fuel in every hamlet, lost its greatest use in my eyes. In 1898 I happened to see what was to me an unknown make of light American electric buggy. It appealed alike to my eye, my needs, and my reason, and I bought it. I have never had cause to regret the purchase. It serves me for running about Paris, and it goes lightly, noiselessly, and without odour.
I had already handed the plan of my balloon envelope to the constructors. It was that of a cylindrical balloon terminating fore and aft in cones, 25 metres (82½" feet) long, with a diameter of 3·5 metres (11½" feet) and a gas capacity of 180 cubic metres (6354 cubic feet). My calculations had left me only 30 kilogrammes (66 lbs.) for both the balloon material and its varnish. Therefore I gave up the usual network and chemise, or outer cover; indeed, I considered this second envelope, holding the balloon proper within it, to be not only superfluous but harmful, if not dangerous. Instead I attached the suspension cords of my basket directly to the balloon envelope by means of small wooden rods introduced into long horizontal hems sewed on both sides to its stuff for a great part of the balloon's length. Again, in order not to pass my 30 kilogrammes (66 lbs.), including varnish, I was obliged to have recourse to my Japanese silk, which had proved so staunch in the "Brazil."
After glancing at this order for the balloon envelope M. Lachambre at first refused it plumply. He would not make himself a party to such rashness. But when I recalled to his memory how he had said the same thing with respect to the "Brazil," and went on to assure him that, if necessary, I would cut and sew the balloon with my own hands, he gave way to me and undertook the job. He would cut and sew and varnish the balloon according to my plans.
The balloon envelope being thus put under way I prepared my basket, motor, propeller, rudder, and machinery. When they were completed I made many trials with them, suspending the whole system by a cord from the rafters of the workshop, starting the motor, and measuring the force of the forward swing caused by the propeller working on the atmosphere behind it. Holding back this forward movement by means of a horizontal rope attached to a dynamometer, I found that the traction power developed by the motor in my propeller with two arms, each measuring one metre across, was as high as 11·4 kilogrammes (25 lbs.). This was a figure that promised good speed to a cylindrical balloon of my dimensions, whose length was equal to nearly seven times its diameter. With 1200 turns to the minute the propeller, which was attached directly to the motor shaft, might easily, if all went well, give the air-ship a speed of not less than 8 metres (26½" feet) per second.
