Part 3 (1/2)
”What! like horse-jockeys?”
”Yes, like jockeys Only, never fear, you won't be expected to o as you are”
”Well, I can tell you, I ahed,” said Kennedy, firmly
”But, sir, it seems that the doctor's machine requires it”
”Well, his machine will have to do without it”
”Huad! that's all I want!”
”Co for us directly”
”I shan't go”
”Oh! now, you won't vex the doctor in that way!”
”Aye! that I will”
”Well!” said Joe with a laugh, ”you say that because he's not here; but when he says to your face, 'dick!' (with all respect to you, sir,) 'dick, I want to know exactly how o, I warrant it”
”No, I will NOT go!”
At this moment the doctor entered his study, where this discussion had been taking place; and, as he caether at his ease
”dick,” said the doctor, ”coh”
”But-”
”You may keep your hat on Come!” And Kennedy went
They repaired in company to the workshop of the Messrs Mitchell, where one of those so-called ”Roman” scales was in readiness It was necessary, by the way, for the doctor to know the weight of his companions, so as to fix the equilibriuet up on the platfor any resistance, said, in an undertone: ”Oh! well, that doesn't bind ”
”One hundred and fifty-three pounds,” said the doctor, noting it down on his tablets
”Am I too heavy?”
”Why, no, Mr Kennedy!” said Joe; ”and then, you know, I a, Joe, with enthusiasm, took his place on the scales, and very nearly upset theton where he is made to ape Achilles, at Hyde-Park entrance, and was superb in it, without the shi+eld
”One hundred and twenty pounds,” wrote the doctor
”Ah! ha!” said Joe, with a smile of satisfaction And why did he smile? He never could tell hiuson-and he put down one hundred and thirty-five pounds to his own account
”All three of us,” said he, ”do not weigh much more than four hundred pounds”
”But, sir,” said Joe, ”if it was necessary for your expedition, I couldso much”
”Useless, my boy!” replied the doctor ”You may eat as much as you like, and here's half-a-crown to buy you the ballast”
CHAPTER SEVENTH
Geometrical Details-Calculation of the Capacity of the Balloon-The Double Receptacle-The Covering-The Car-The Mysterious Apparatus-The Provisions and Stores-The Final Sued upon the details of his expedition It is easy to comprehend that the balloon-that h the air-was the constant object of his solicitude
At the outset, in order not to give the balloon too ponderous dias, which is fourteen and a half tias is easy, and it has given the greatest satisfaction hitherto in aerostatic experi to very accurate calculations, found that, including the articles indispensable to his journey and his apparatus, he should have to carry a weight of 4,000 pounds; therefore he had to find out ould be the ascensional force of a balloon capable of raising such a weight, and, consequently, ould be its capacity
A weight of four thousand pounds is represented by a displaceht hundred and forty-seven cubic feet; or, in other words, forty-four thousand eight hundred and forty-seven cubic feet of air weigh about four thousand pounds
By giving the balloon these cubic dias, instead of cohter and weighing therefore only two hundred and seventy-six pounds-a difference of three thousand seven hundred and twenty-four pounds in equilibriuht of the gas contained in the balloon and the weight of the surrounding atmosphere that constitutes the ascensional force of the forht hundred and forty-seven cubic feet of gas of which we speak, all introduced into the balloon, it would be entirely filled; but that would not do, because, as the balloon continued to as within would dilate, and soon burst the cover containing it Balloons, then, are usually only two-thirds filled
But the doctor, in carrying out a project known only to himself, resolved to fill his balloon only one-half; and, since he had to carry forty-four thousand eight hundred and forty-seven cubic feet of gas, to give his balloon nearly double capacity he arranged it in that elongated, oval shape which has come to be preferred The horizontal diameter was fifty feet, and the vertical diameter seventy-five feet He thus obtained a spheroid, the capacity of which amounted, in round nuuson have used two balloons, his chances of success would have been increased; for, should one burst in the air, he could, by throwing out ballast, keep hiement of two balloons would, necessarily, be very difficult, in view of the problem how to keep the pondered the ees of two balloons, without incurring their inconveniences He constructed two of different sizes, and inclosed the ser one His external balloon, which had the diiven above, contained a less one of the same shape, which was only forty-five feet in horizontal, and sixty-eight feet in vertical diameter The capacity of this interior balloon was only sixty-seven thousand cubic feet: it was to float in the fluid surrounding it A valve opened from one balloon into the other, and thus enabled the aeronaut to coeas had to be let off, so as to descend, that which was in the outer balloon would go first; and, were it completely emptied, the sht then be cast off as a useless encumbrance; and the second balloon, left free to itself, would not offer the same hold to the currents of air as a half-inflated one must needs present
Moreover, in case of an accident happening to the outside balloon, such as getting torn, for instance, the other would reht Lyons silk, coated with gutta percha This gummy, resinous substance is absolutely water-proof, and also resists acids and gas perfectly The silk was doubled, at the upper extremity of the oval, where most of the strain would co fluid for any length of tihed half a pound per nine square feet Hence the surface of the outside balloon being about eleven thousand six hundred square feet, its envelope weighed six hundred and fifty pounds The envelope of the second or inner balloon, having nine thousand two hundred square feet of surface, weighed only about five hundred and ten pounds, or say eleven hundred and sixty pounds for both
The network that supported the car washempen cord, and the two valves were the object of the most minute and careful attention, as the rudder of a shi+p would be
The car, which was of a circular form and fifteen feet in diaht covering of iron, and protected below by a systes, to deaden the shock of collision Its weight, along with that of the network, did not exceed two hundred and fifty pounds
In addition to the above, the doctor caused to be constructed two sheet-iron chests two lines in thickness These were connected by means of pipes furnished with stopcocks He joined to these a spiral, two inches in diath, the longer of which, however, enty-five feet in height and the shorter only fifteen feet
These sheet-iron chests were embedded in the car in such a way as to take up the least possible amount of space The spiral, which was not to be adjusted until so with a very strong Buntzen electric battery This apparatus had been so ingeniously coh allons of water in another receptacle
The instruments provided for the journey consisted of two barometers, two thermometers, two compasses, a sextant, two chronometers, an artificial horizon, and an altaziht of distant and inaccessible objects