In a few moments Ayrault returned with pencils, a pair of compasses, and paper.

"Let us see, in the first place," said Deepwaters, "how long the journey will take. Since a stone falls 16.09 feet the first second, and 64+ feet the next, it is easy to calculate at what rate your speed would increase with the repulsion twice that of the ordinary traction. But I think this would be too slow. It will be best to treble or quadruple the apergetic charge, which can easily be done, in which case your speed will exceed the muzzle-velocity of a projectile from a long-range gun, in a few seconds. As the earth's repulsion decreases, the attraction of mars and Jupiter will increase, and, there being no resistance, your gait will become more and more rapid till it is necessary to reverse the charge to avoid being dashed to pieces or being consumed like a falling star by the friction in passing through Jupiter's atmosphere. You can be on the safe side by checking your speed in advance. You must, of course, be careful to avoid collisions with meteors and asteroids but if you do, they will be of use to you, for by attracting or repelling them you can change your course to suit yourself, and also theirs in inverse ratio to their masses. Jupiter's moons will be like head and stern lines in enabling you to choose the part of the surface on which you wish to land. With apergy it is as essential to have some heavy body on which to work, within range, as to have water about a ship's propellers. Whether, when apergy is developed, gravitation is temporarily annulled, or reversed like the late attraction of a magnet when the current is changed, or whether it is merely overpowered, in which case your motion will be the resultant of the two, is an unsettled and not very important point; for, though we know but little more of the nature of electricity than was known a hundred years ago, this does not prevent our producing and using it."

"Jupiter, when in opposition," he continued, "is about 380,000,000 miles from us, and it takes light, which travels at the rate of 190,000 miles a second, just thirty-four minutes to reach the earth from Jupiter. If we suppose the average speed of your ship to be one- five-hundredth as great, it will take you just eleven days, nineteen hours and twenty minutes to make the journey. You will have a fine view of Mars and the asteroids, and when 1,169,000 miles from Jupiter, will cross the orbit of Callisto, the fifth moon in distance from the giant planet. That will be your best point to steer by."

"I think," said Ayrault, "as that will be the first member of Jupiter's system we pass, and as it will guide us into port, it would be a good name for our ship, and you must christen her if we have her launched."

"No, no," said Deepwaters, "Miss Preston must do that; but we certainly should have a launch, for you might have to land in the water, and you must be sure the ship is tight."

"Talking of tight ships," said Bearwarden, passing a decanter of claret to Stillman, "may remind us that it is time to splice the 'main brace.' There's a bottle of whisky and some water just behind you," he added to Deepwaters, "while three minutes after I ring this bell," he said, pressing a button and jerking a handle marked '8,' "the champagne cocktails will be on the desk."

"I see you know his ways," said Stillman to Bearwarden, drooping his eyes in Deepwaters's direction.

"Oh, yes, I've been here before," replied Deepwaters. "You see, we navy men have to hustle now-a-days, and can't pass our time in a high-backed chair, talking platitudes."

At this moment there was a slight rumbling, and eight champagne cocktails, with the froth still on, and straws on a separate plate, shot in and landed on a corner of the desk.

"Help yourselves, gentlemen," said Bearwarden, placing them on a table; "I hope we shall find them cold."

"Do you know," said Deepwaters to Ayrault, while rapidly making his cocktail disappear, "the Callisto's cost with its outfit will be very great, especially if you use glucinum, which, though the ideal metal for the purpose, comes pretty high? I suggest that you apply to Congress for an appropriation. This experiment comes under the 'Promotion of Science Act,' and any bill for it would certainly pass."

"No, indeed," replied Ayrault; "the Callisto trip will be a privilege and glory I would not miss, and building her will be a part of it. I shall put in everything conducive to success, but will come to the Government only for advice."

"I will send a letter to all our ambassadors and consuls," said Stillman, "to telegraph the department anything they may know or learn that will be of use in adjusting the batteries, controlling the machine, or anything else, and will turn over to you in a succinct form all information that may be relevant, for without such sorting you would be overwhelmed."