Off on a Comet! a Journey through Planetary Space

by Jules Verne

  CHAPTER VII. GALLIA WEIGHED

  A quarter of an hour later, the visitors to the _Hansa_ had reassembledin the common hall of Nina's Hive.

  "Now, gentlemen, we can proceed," said the professor. "May I requestthat this table may be cleared?"

  Ben Zoof removed the various articles that were lying on the table, andthe coins which had just been borrowed from the Jew were placed upon itin three piles, according to their value.

  The professor commenced. "Since none of you gentlemen, at the timeof the shock, took the precaution to save either a meter measure ora kilogramme weight from the earth, and since both these articles arenecessary for the calculation on which we are engaged, I have beenobliged to devise means of my own to replace them."

  This exordium delivered, he paused and seemed to watch its effectupon his audience, who, however, were too well acquainted with theprofessor's temper to make any attempt to exonerate themselves from therebuke of carelessness, and submitted silently to the implied reproach.

  "I have taken pains," he continued, "to satisfy myself that thesecoins are in proper condition for my purpose. I find them unworn andunchipped; indeed, they are almost new. They have been hoarded insteadof circulated; accordingly, they are fit to be utilized for my purposeof obtaining the precise length of a terrestrial meter."

  Ben Zoof looked on in perplexity, regarding the lecturer with much thesame curiosity as he would have watched the performances of a travelingmountebank at a fair in Montmartre; but Servadac and his two friends hadalready divined the professor's meaning. They knew that French coinageis all decimal, the franc being the standard of which the other coins,whether gold, silver, or copper, are multiples or measures; they knew,too, that the caliber or diameter of each piece of money is rigorouslydetermined by law, and that the diameters of the silver coinsrepresenting five francs, two francs, and fifty centimes measurethirty-seven, twenty-seven, and eighteen millimeters respectively; andthey accordingly guessed that Professor Rosette had conceived the planof placing such a number of these coins in juxtaposition that thelength of their united diameters should measure exactly the thousandmillimeters that make up the terrestrial meter.

  The measurement thus obtained was by means of a pair of compassesdivided accurately into ten equal portions, or decimeters, each ofcourse 3.93 inches long. A lath was then cut of this exact length andgiven to the engineer of the _Dobryna_, who was directed to cut out ofthe solid rock the cubic decimeter required by the professor.

  The next business was to obtain the precise weight of a kilogramme. Thiswas by no means a difficult matter. Not only the diameters, but also theweights, of the French coins are rigidly determined by law, and as thesilver five-franc pieces always weigh exactly twenty-five grammes,the united weight of forty of these coins is known to amount to onekilogramme.

  "Oh!" cried Ben Zoof; "to be able to do all this I see you must be richas well as learned."

  With a good-natured laugh at the orderly's remark, the meeting adjournedfor a few hours. By the appointed time the engineer had finished histask, and with all due care had prepared a cubic decimeter of thematerial of the comet.

  "Now, gentlemen," said Professor Rosette, "we are in a position tocomplete our calculation; we can now arrive at Gallia's attraction,density, and mass."

  Everyone gave him his complete attention.

  "Before I proceed," he resumed, "I must recall to your minds Newton'sgeneral law, 'that the attraction of two bodies is directly proportionalto the product of their masses, and inversely proportional to the squareof their distances.'"

  "Yes," said Servadac; "we remember that."

  "Well, then," continued the professor, "keep it in mind for afew minutes now. Look here! In this bag are forty five-francpieces--altogether they weigh exactly a kilogramme; by which I mean thatif we were on the earth, and I were to hang the bag on the hook of thesteelyard, the indicator on the dial would register one kilogramme. Thisis clear enough, I suppose?"

  As he spoke the professor designedly kept his eyes fixed upon Ben Zoof.He was avowedly following the example of Arago, who was accustomedalways in lecturing to watch the countenance of the least intelligentof his audience, and when he felt that he had made his meaning clear tohim, he concluded that he must have succeeded with all the rest. Inthis case, however, it was technical ignorance, rather than any lackof intelligence, that justified the selection of the orderly for thisspecial attention.

  Satisfied with his scrutiny of Ben Zoof's face, the professor went on."And now, gentlemen, we have to see what these coins weigh here uponGallia."

  He suspended the money bag to the hook; the needle oscillated, andstopped. "Read it off!" he said.

  The weight registered was one hundred and thirty-three grammes.

  "There, gentlemen, one hundred and thirty-three grammes! Less thanone-seventh of a kilogramme! You see, consequently, that the force ofgravity here on Gallia is not one-seventh of what it is upon the earth!"

  "Interesting!" cried Servadac, "most interesting! But let us go on andcompute the mass."

  "No, captain, the density first," said Rosette.

  "Certainly," said the lieutenant; "for, as we already know the volume,we can determine the mass as soon as we have ascertained the density."

  The professor took up the cube of rock. "You know what this is," he wenton to say. "You know, gentlemen, that this block is a cube hewn fromthe substance of which everywhere, all throughout your voyage ofcircumnavigation, you found Gallia to be composed--a substance to whichyour geological attainments did not suffice to assign a name."

  "Our curiosity will be gratified," said Servadac, "if you will enlightenour ignorance."

  But Rosette did not take the slightest notice of the interruption.

  "A substance it is which no doubt constitutes the sole material ofthe comet, extending from its surface to its innermost depths. Theprobability is that it would be so; your experience confirms thatprobability: you have found no trace of any other substance. Of thisrock here is a solid decimeter; let us get at its weight, and we shallhave the key which will unlock the problem of the whole weight ofGallia. We have demonstrated that the force of attraction here is onlyone-seventh of what it is upon the earth, and shall consequently have tomultiply the apparent weight of our cube by seven, in order to ascertainits proper weight. Do you understand me, goggle-eyes?"

  This was addressed to Ben Zoof, who was staring hard at him. "No!" saidBen Zoof.

  "I thought not; it is of no use waiting for your puzzle-brains to makeit out. I must talk to those who can understand."

  The professor took the cube, and, on attaching it to the hook of thesteelyard, found that its apparent weight was one kilogramme and fourhundred and thirty grammes.

  "Here it is, gentlemen; one kilogramme, four hundred and thirty grammes.Multiply that by seven; the product is, as nearly as possible, tenkilogrammes. What, therefore, is our conclusion? Why, that the densityof Gallia is just about double the density of the earth, which we knowis only five kilogrammes to a cubic decimeter. Had it not been forthis greater density, the attraction of Gallia would only have beenone-fifteenth instead of one-seventh of the terrestrial attraction."

  The professor could not refrain from exhibiting his gratification that,however inferior in volume, in density, at least, his comet had theadvantage over the earth.

  Nothing further now remained than to apply the investigations thusfinished to the determining of the mass or weight. This was a matter oflittle labor.

  "Let me see," said the captain; "what is the force of gravity upon thevarious planets?"

  "You can't mean, Servadac, that you have forgotten that? But you alwayswere a disappointing pupil."

  The captain could not help himself: he was forced to confess that hismemory had failed him.

  "Well, then," said the professor, "I must remind you. Taking theattraction on the earth as 1, that on Mercury is 1.15, on Venus itis 0.92, on Mars 0.5, and on Jupiter 2.45; on the moon the attraction is 0.16,whilst on the surface
of the sun a terrestrial kilogramme would weigh 28kilogrammes."

  "Therefore, if a man upon the surface of the sun were to fall down, hewould have considerable difficulty in getting up again. A cannon ball,too, would only fly a few yards," said Lieutenant Procope.

  "A jolly battle-field for cowards!" exclaimed Ben Zoof.

  "Not so jolly, Ben Zoof, as you fancy," said his master; "the cowardswould be too heavy to run away."

  Ben Zoof ventured the remark that, as the smallness of Gallia secured toits inhabitants such an increase of strength and agility, he was almostsorry that it had not been a little smaller still.

  "Though it could not anyhow have been very much smaller," he added,looking slyly at the professor.

  "Idiot!" exclaimed Rosette. "Your head is too light already; a puff ofwind would blow it away."

  "I must take care of my head, then, and hold it on," replied theirrepressible orderly.

  Unable to get the last word, the professor was about to retire, whenServadac detained him.

  "Permit me to ask you one more question," he said. "Can you tell me whatis the nature of the soil of Gallia?"

  "Yes, I can answer that. And in this matter I do not think yourimpertinent orderly will venture to put Montmartre into the comparison.This soil is of a substance not unknown upon the earth." And speakingvery slowly, the professor said: "It contains 70 per cent. of tellurium,and 30 per cent. of gold."

  Servadac uttered an exclamation of surprise.

  "And the sum of the specific gravities of these two substances is 10,precisely the number that represents Gallia's density."

  "A comet of gold!" ejaculated the captain.

  "Yes; a realization of what the illustrious Maupertuis has alreadydeemed probable," replied the astronomer.

  "If Gallia, then, should ever become attached to the earth, might it notbring about an important revolution in all monetary affairs?" inquiredthe count.

  "No doubt about it!" said Rosette, with manifest satisfaction. "It wouldsupply the world with about 246,000 trillions of francs."

  "It would make gold about as cheap as dirt, I suppose," said Servadac.

  The last observation, however, was entirely lost upon the professor, whohad left the hall with an air almost majestic, and was already on hisway to the observatory.

  "And what, I wonder, is the use of all these big figures?" said Ben Zoofto his master, when next day they were alone together.

  "That's just the charm of them, my good fellow," was the captain's coolreply, "that they are of no use whatever."