thermometer only falls a degree centigrade for every seventy meters
of elevation the temperature was not insupportable. And so, in
chatting and thinking and waiting for the engineer, Uncle Prudent and
Phil Evans walked about beneath the forest of screws, whose gyratory
movement gave their arms the appearance of semi-diaphanous disks.

The State of Illinois was left by its northern frontier in less than
two hours and a half; and they crossed the Father of Waters, the
Mississippi, whose double-decked steam-boats seemed no bigger than
canoes. Then the "Albatross" flew over Iowa after having sighted Iowa
City about eleven o'clock in the morning.

A few chains of hills, "bluffs" as they are called, curved across the
face of the country trending from the south to the northwest, whose
moderate height necessitated no rise in the course of the aeronef.
Soon the bluffs gave place to the large plains of western Iowa and
Nebraska--immense prairies extending all the way to the foot of the
Rocky Mountains. Here and there were many rios, affluents or minor
affluents of the Missouri. On their banks were towns and villages,
growing more scattered as the "Albatross" sped farther west.

Nothing particular happened during this day. Uncle Prudent and Phil
Evans were left entirely to themselves. They hardly noticed Frycollin
sprawling at full length in the bow, keeping his eyes shut so that he
could see nothing. And they were not attacked by vertigo, as might
have been expected. There was no guiding mark, and there was nothing
to cause the vertigo, as there would have been on the top of a lofty
building. The abyss has no attractive power when it is gazed at from
the car of a balloon or deck of an aeronef. It is not an abyss that
opens beneath the aeronaut, but an horizon that rises round him on