“Gentlemen.” said he, “you ask yourselves doubtless if this apparatus, so marvelously adapted for aerial locomotion, is susceptible of receiving greater speed. It is not worth while to conquer space if we cannot devour it. I wanted the air to be a solid support to me, and it is. I saw that to struggle against the wind I must be stronger than the wind, and I am. I had no need of sails to drive me, nor oars nor wheels to push me, nor rails to give me a faster road. Air is what I wanted, that was all. Air surrounds me as it surrounds the submarine boat, and in it my propellers act like the screws of a steamer. That is how I solved the problem of aviation. That is what a balloon will never do, nor will any machine that is lighter than air.” Silence, absolute, on the part of the colleagues, which did not for a moment disconcert the engineer. He contented himself with a half-smile, and continued in his interrogative style, “Perhaps you ask if to this power of the “Albatross” to move horizontally there is added an equal power of vertical movement—in a word, if, when, we visit the higher zones of the atmosphere, we can compete with an aerostat? Well, I should not advise you to enter the “Go-Ahead” against her!” The two colleagues shrugged their shoulders. That was probably what the engineer was waiting for. Robur made a sign. The propelling screws immediately stopped, and after running for a mile the “Albatross” pulled up motionless. At a second gesture from Robur the suspensory helices revolved at a speed that can only be compared to that of a siren in acoustical experiments. Their f-r-r-r-r rose nearly an octave in the scale of sound, diminishing gradually in intensity as the air became more rarified, and the machine rose vertically, like a lark singing his song in space. “Master! Master!” shouted Frycollin. “See that it doesn’t break!” A smile of disdain was Robur’s only reply. In a few minutes the “Albatross” had attained the height of 8,700 feet, and extended the range of vision by seventy miles, the barometer having fallen 480 millimeters. Then the “Albatross” descended. The diminution of the pressure in high altitudes leads to the diminution of oxygen in the air, and consequently in the blood. This has been the cause of several serious accidents which have happened to aeronauts, and Robur saw no reason to run any risk. The “Albatross” thus returned to the height she seemed to prefer, and her propellers beginning again, drove her off to the southwest. “Now, sirs, if that is what you wanted you can reply.” Then, leaning over the rail, he remained absorbed in contemplation. When he raised his head the president and secretary of the Weldon Institute stood by his side. “Engineer Robur.” said Uncle Prudent, in vain endeavoring to control himself, “we have nothing to ask about what you seem to believe, but we wish to ask you a question which we think you would do well to answer.” “Speak.”