Robur had not yet found imitators.

The chance of encountering an aerostat gliding through the air was too remote to be regarded.

In any case it would be all the worse for the aerostat--the earthen pot and the iron pot.

The "Albatross" had nothing to fear from the collision.
But what could happen?
The aeronef might find herself like a ship on a lee shore if a mountain that could not be outflanked or passed barred the way.

These are the reefs of the air, and they have to be avoided as a ship avoids the reefs of the sea.