forth, back and forth, with the speed and motion of swallows.

So this was the meaning of the giant reciprocal engine! Instead of
the screw propeller which characterized earth's aircraft, these
vessels employed the true bird principle, combining it with the
simple methods of primitive sailing craft.

As soon as the ship stopped its wind-driven rush and began to employ
its wings, the speed straightway slackened; and the ships began to
descend. About the same time the figures of several people appeared
on what might be called the bridge; and assuming that these people
were as large as the man whom Smith had seen enter the engine-room--a
chap of average height--then that ship, in proportion, was all of a
mile long!

But Smith's awe was not shared by his agent, who turned
indifferently away and looked about the sky as though in search of
other sights. In doing so, he leaned over the deck's railing; and
Smith saw the sheer sides of the giant ship, extending fore and aft
almost indefinitely; while far overhead billowed vast clouds of
white cloth. The vessel was now under sail.

About a mile higher up, and almost that distance to one side, the
agent's eyes made out two tiny specks. He watched them closely for a
moment as they pitched and tossed queerly about; then darted into
the engine-room, secured a pair of binoculars of an old, squat
pattern, and swiftly focused upon the nearer of the two.

Smith instantly sensed a disaster. The object was a small air-craft,
of a sort entirely strange to the engineer; yet he knew that it was