Robur remained impassible, and continued: "There is no progress for your aerostats, my citizen balloonists; progress is for flying machines. The bird flies, and he is not a balloon, he is a piece of mechanism!"

"Yes, he flies!" exclaimed the fiery Bat T. Fynn; "but he flies against all the laws of mechanics."

"Indeed!" said Robur, shrugging his shoulders, and resuming, "Since we have begun the study of the flight of large and small birds one simple idea has prevailed--to imitate nature, which never makes mistakes. Between the albatross, which gives hardly ten beats of the wing per minute, between the pelican, which gives seventy --"

"Seventy-one," said the voice of a scoffer.

"And the bee, which gives one hundred and ninety-two per second --"

"One hundred and ninety-three!" said the facetious individual.

"And, the common house fly, which gives three hundred and thirty --"

"And a half!"

"And the mosquito, which gives millions --"

"No, milliards!"

But Robur, the interrupted, interrupted not his demonstration. "Between these different rates --" he continued.

"There is a difference," said a voice.

"There is a possibility of finding a practical solution. When De Lucy showed that the stag beetle, an insect weighing only two grammes, could lift a weight of four hundred grammes, or two hundred times its own weight, the problem of aviation was solved. Besides, it has been shown that the wing surface decreases in proportion to the increase of the size and weight of the animal. Hence we can look forward to such contrivances --"

"Which would never fly!" said secretary Phil Evans.

"Which have flown, and which will fly," said Robur, without being in the least disconcerted, "and which we can call streophores, helicopters, orthopters--or, in imitation of the word 'nef,' which comes from 'navis,' call them from 'avis,' 'efs,'--by means of which man will become the master of space. The helix --"

"Ah, the helix!" replied Phil Evans. "But the bird has no helix; that we know!"

"So," said Robur; "but Penaud has shown that in reality the bird makes a helix, and its flight is helicopteral. And the motor of the future is the screw --"

"From such a maladee Saint Helix keep us free!" sung out one of the members, who had accidentally hit upon the air from Herold's "Zampa."

And they all took up the chorus: "From such a maladee Saint Helix keep us free!" with such intonations and variations as would have made the French composer groan in his grave.

As the last notes died away in a frightful discord Uncle Prudent took advantage of the momentary calm to say, "Stranger, up to now, we let you speak without interruption." It seemed that for the president of the Weldon Institute shouts, yells, and catcalls were not interruptions, but only an exchange of arguments.

"But I may remind you, all the same, that the theory of aviation is condemned beforehand, and rejected by the majority of American and foreign engineers. It is a system which was the cause of the death of the Flying Saracen at Constantinople, of the monk Volador at Lisbon, of De Leturn in 1852, of De Groof in 1864, besides the victims I forget since the mythological Icarus --"

"A system," replied Robur, "no more to be condemned than that whose martyrology contains the names of Pilâtre de Rozier at Calais, of Blanchard at Paris, of Donaldson and Grimwood in Lake Michigan, of Sivel and of Crocé-Spinelli, and others whom it takes good care, to forget."

This was a counter-thrust with a vengeance.

"Besides," continued Robur, "With your balloons as good as you can make them you will never obtain any speed worth mentioning. It would take you ten years to go round the world--and a flying machine could do it in a week!"

Here arose a new tempest of protests and denials which lasted for three long minutes. And then Phil Evans look up the word.

"Mr. Aviator," he said "you who talk so much of the benefits of aviation, have you ever aviated?"

"I have."

"And made the conquest of the air?"

"Not unlikely."

"Hooray for Robur the Conqueror!" shouted an ironical voice.