IN the early spring of 1899 I built another air-ship, which the Paris public at once called "The Santos-Dumont No. 2." It had the same length and, at first sight, the same form as the "No. 1"; but its greater diameter brought its volume up to 200 cubic metres—over 7000 cubic feet—and gave me 20 kilogrammes (44 lbs.) more ascensional force. I had taken account of the insufficiency of the air pump that had all but killed me, and had added a little aluminium ventilator to make sure of permanency in the form of the balloon.

This ventilator was a rotary fan, worked by the motor, to send air into the little interior air balloon, which was sewed inside to the bottom of the great balloon like a kind of closed pocket. In Fig. 5 G is the great balloon filled with hydrogen gas, A the interior air balloon, VV the automatic gas valves, AV the latter's air valve, and TV the