Then, amid profound silence, the engineer's voice was heard.

"Citizens of the United States," he said, "The president and secretary of the Weldon Institute are again in my power. In keeping them I am only within my right. But from the passion kindled in them by the success of the "Albatross" I see that their minds are not prepared for that important revolution which the conquest of the air will one day bring, Uncle Prudent and Phil Evans, you are free!"

The president, the secretary, and the aeronaut had only to jump down.

Then Robur continued.

"Citizens of the United States, my experiment is finished; but my advice to those present is to be premature in nothing, not even in progress. It is evolution and not revolution that we should seek. In a word, we must not be before our time. I have come too soon today to withstand such contradictory and divided interests as yours. Nations are not yet fit for union.

"I go, then; and I take my secret with me. But it will not be lost to humanity. It will belong to you the day you are educated enough to profit by it and wise enough not to abuse it. Citizens of the United States--Good-by!"

And the "Albatross," beating the air with her seventy-four screws, and driven by her propellers, shot off towards the east amid a tempest of cheers.

The two colleagues, profoundly humiliated, and through them the whole Weldon Institute, did the only thing they could. They went home.

And the crowd by a sudden change of front greeted them with particularly keen sarcasms, and, at their expense, are sarcastic still.

And now, who is this Robur? Shall we ever know?

We know today. Robur is the science of the future. Perhaps the science of tomorrow. Certainly the science that will come!

Does the "Albatross" still cruise in the atmosphere in the realm that none can take from her? There is no reason to doubt it.

Will Robur, the Conqueror, appear one day as he said? Yes! He will come to declare the secret of his invention, which will greatly change the social and political conditions of the world.

As for the future of aerial locomotion, it belongs to the aeronef and not the aerostat.

It is to the "Albatross" that the conquest of the air will assuredly fall.

--End of Voyage Extraordinaire--Robur the Conqueror--