I have said that, as it was originally proportioned, the balloon of this smallest of possible dirigibles permitted me to take up less than 30 kilogrammes (66 lbs.) of ballast. As now enlarged its lifting power is greater; but when account is taken of my own weight and the weight of keel, motor, screw, and machinery, the whole system becomes neither lighter nor heavier than the surrounding atmosphere when I have loaded it with 60 kilogrammes (132 lbs.) of ballast; and it is just in this connection that it will be easiest to explain why I have called this little air-ship very practical. On Monday, 29th June 1903, I landed with it on the grounds of the Aéro Club at St Cloud in the midst of six inflated spherical balloons. After a short call I started off again.
"Can we not give you some gas?" politely asked my fellow-clubmen.
[Illustration: "No. 9." SHOWING RELATIVE SIZE]
"You saw me coming all the way from Neuilly," I replied; "did I throw out any ballast?"
"You threw out no ballast," they admitted.
As a matter of scientific curiosity I may relate that I did not either lose or sacrifice a cubic foot of gas or a single pound of ballast that whole afternoon--nor has that experience been at all exceptional in the very practical little "No. 9" or even in its predecessors. It will be remembered that on the day succeeding the winning of the Deutsch prize my chief mechanician found that the balloon of my "No. 6" would take no gas because none had been lost.
After leaving my fellow-clubmen at St Cloud that afternoon I made a typically practical trip. To go from Neuilly St James to the Aéro Club's grounds I had already passed the Seine. Now, crossing it again, I made the café-restaurant of "The Cascade," where I stopped for refreshments. It was by this time 5 P.M. Not wishing to return yet to my station I crossed the Seine for a third time and went in a straight course as close to the great fort of Mount Valerien as delicacy permitted. Then, returning, I traversed the river once again and came to earth in my own grounds at Neuilly.
During the whole trip my greatest altitude was 105 metres (346 feet). Taking into consideration that my guide rope hangs 40 metres (132 feet) below me, and that the tops of the Bois trees extend up some 20 metres (70 feet) from the ground, this extreme altitude left me but 40 metres (140 feet) of clear space for vertical manoeuvring.