GRAND HAVEN.
Jerrold soon demonstrated the fact that the Eagle was a much faster craft than the Hawk. As already stated, there was scarcely any wind, so the Eagle had practically no adverse air current to contend against. Pointing the air ship east by south, Jerrold tuned up the engine, and the speed they made was marvelous. They could form a tolerable idea of the swiftness of their flight by watching the surface of the earth, some five hundred feet below them.
"She's certainly a swifter craft than the Hawk," remarked Ferral.
"I will improve the Hawk for you," said Jerrold, "so she will be just as swift as the Eagle."
"Oof ve efer ged der Hawk pack, vich ve don'd know," struck in Carl.
"We must get her back," averred Matt.
"The biggest trouble with air ships equipped with gasoline," continued Jerrold, "is the fact that the slightest change in the temperature affects the buoyancy. Even a cloud over the sun will cause the gas to contract, and the difference in heat thrown off by the sun at morning and noon will expand the gas and also disturb the equilibrium. Now I have an improvement that remedies that. It consists of a smaller bag inside the gas bag, filled with a vapor of my own invention. When the buoyancy of the outer bag decreases, that of the inner bag increases, and vice versa. That gives us a unit of buoyancy which is always the same, and leaves the propeller free to carry us in any direction."
"Greadt!" cried Carl. "I don'd ondershtand vat you vas gedding ad, aber I bed it vas somet'ing fine. Ach!" and he looked downward, "here ve go ofer der lake. I hope dere iss some ships all along der vay, so dot oof anyt'ing habbens ve can trop down ondo vone oof dem."
"Don't worry about our dropping into the water, Carl," smiled Jerrold, "for there is absolutely no danger of that."
In an hour the Eagle was out of sight of land. The sails of one or two schooners could be seen far away on the horizon, but they were too far off to be considered "company."