Page:Sim pall-mall-magazine 1904-01 32 129.pdf/21

 15 say the least. As it was, I had a bad shaking up.

I have been so often and so sincerely warned against what is taken for granted to be the principal and patent danger of operating explosive engines under masses of inflammable gases, that I may be pardoned for stopping a moment to disclaim undue or thoughtless rashness.

Photo by P. Raffaels.

Very naturally, from the first, the question of physical danger to myself called for consideration. I was the interested party; and I tried to view the question from all points. Well, the outcome of these meditations was to make me fear fire very little, while doubting other possibilities against which no one ever dreamed of warning me!

I remember that while working on this the first of all my air-ships—in a little carpenter's-shop of the Rue du Colisée, I used to wonder how the vibrations of the petroleum motor would affect the system when it should get into the air.

In those days we did not have the noiseless automobiles, free from great vibration, of the present. Nowadays even the colossal 80-and 90-horse-power motors of the latest racing types can be started and stopped as gently as those great steel hammers in iron foundries, whose engineers make a trick of cracking the top of an egg with them without breaking the rest of the shell.

My tandem-motor of two cylinders working the same connecting-rod and fed by a single carburator produced 3$$\frac{1}{2},$$ horse-power—at that time a considerable force for its weight; and I had no idea how it would act off terra firma. I had seen motors "jump" along the highway. What would mine do in its little basket that weighed almost nothing, and suspended from a balloon that weighed less than nothing?

You know the principle of these motors? One may say that there is gasoline in a receptacle. Hot 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, driving 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 force. Then it goes up, throwing