You know the principle of these motors? One may say that there is gasoline in a receptacle. Air passing through it comes out mixed with gasoline gas, ready to explode. You give a whirl to a crank, and the thing begins working automatically. The piston goes down, sucking combined gas and air into the cylinder. Then the piston comes back and compresses it. At that moment an electric spark is struck. An explosion follows instantly; and the piston goes down, producing work. Then it goes up, throwing out the product of combustion. Thus with the two cylinders there was one explosion for every turn of the shaft.
Wishing to have my mind clear on the question I took my tricycle, just as it was after I had left the Paris-Amsterdam race, and, accompanied by a capable companion, I steered it to a lonely part of the Bois de Boulogne. There in the forest I chose a great tree with low-hanging limbs. From two of them we suspended the motor tricycle by three ropes.
When we had well established the suspension my companion aided me to climb up and seat myself on the tricycle saddle. I was as in a swing. In a moment I would start the motor and learn something of my future success or failure.
Would the vibration of the explosive engine shake me back and forth, strain at the ropes until it had unequalised their tension, and then break them one by one? Would it jar the interior air balloon's pump and derange the big balloon's valves? Would it continually jerk and pull at the silk hems and the thin rods which were to hold my basket to the balloon? Free from the steadying influence of the solid ground, would the jumping motor jar itself until it broke? And, breaking, might it not explode?
All this and more had been predicted by the professional aeronauts, and I had as yet no proof outside of reasoning that they might not be right on this or that topic.
I started the motor. I felt no particular vibration, and I was certainly not being shaken. I increased the speed, and felt _less_ vibration! There could be no doubt about it--there was less vibration in this light-weight tricycle hanging in the air than I had regularly felt while travelling on the ground. It was my first triumph in the air!
I will say frankly that as I rose in the air on my first trip I had no fear of fire. What I feared was that the balloon might burst by reason of its interior pressure. I still fear it.