CHAPTER XIII
The Mystery of a Minus Weight
It was the doctor himself who gave the name Space Fever (now sogenerally adopted) to the peculiar malady from which he suffered in thatlong period when weight was very slight or nothing at all. A littlereflection on the physiological bearings of the conditions we werepassing through, will serve to explain the illness.
For the period of a month, owing to the impossibility of effort, therewas scarcely any wasting of our bodily tissues, and very little need foroxydization of the blood. The limbs, which the heart really workshardest to serve, did scarcely any labour and needed very little blood.But the heart had its stubborn habits the same as the other muscles. Itis a high-pressure engine, and there is no way of slowing it downmaterially. It kept up its vigorous pumping and driving just as if thegreat muscles of the limbs had wasted and needed building up, and justas if it had the task of forcing the blood through those parts of thebody usually compressed by its weight or strained by the effort ofcarrying it. The result was much the same as if your heart now shouldsuddenly begin to beat much too fast, the blood was heated into a stateof fever, which naturally increased as we lost weight, culminated at thedead-line and began decreasing as soon as we commenced having a weighttoward Mars. It was only my fortunate invention of a method of exercise,and my religious adherence to it, which saved me from a similar attack.
But many things happened before the doctor recovered consciousness. TheMoon had re-appeared on the other side of the Earth-spot, the lightabout us had grown less dazzling than sunlight on Earth, and thetemperature had fallen to four degrees. It was perhaps two days afterpassing the dead-line that, as I was gazing carefully out of the forwardwindow, I saw far to the right of us a large circular patch of faintlyredder light in the general curtain of white. Its size quite startledme, for it was rather larger than a full moon, and I had expected Marsto re-appear as a very bright star before we could distinguish any discwith the naked eye. This misapprehension probably arose from the factthat I had thought the dead-line about half way between the two planets,which upon reflection I saw to be impossible, as it must be much nearerthe smaller planet.
The outline of the planet was not clearly visible yet, but I could nothave missed seeing that red glow long before, had it been more directlyin front of us. Evidently we were steering much ahead of the planet,which indicated that we were arriving before opposition. I immediatelychanged our course so as to go more nearly toward it, but yet to keep alittle ahead. Then I hastily brought the telescope back to the forwardcompartment, which was now the bottom of the projectile. The lenseseasily pierced the curtain of light that seemed to be hung in front ofthe new planet, and I could distinguish the outline of the greatlymagnified orb very clearly.
Judging from appearances, it could not be farther from us than twice thedistance of the Moon from the Earth. I resorted to the scales at once,and found that weight was beginning slowly to return, for I weighed alittle less than an ounce. From a rule the doctor had explained to me, Icalculated that this indicated a distance from the planet of about fourhundred thousand miles, if it really was Mars. But I had some doubtsabout its really being that planet; for a clear white, irregular-shapedspot upon it, which I had noticed as soon as the telescope was focussed,did not appear to move at all, as it should have done had it been upon arotating planet. Upon closer observation, I detected a dull, greenishspot, just coming upon the lower edge. But when I looked again a brightwhite and perfectly circular spot had appeared in the same place andcovered it up. But this new white spot travelled much more rapidly, andsoon uncovered the greenish spot, which seemed to move in the same path,but much more slowly. This was something I could not understand. Thewhite circle was too bright and regular to be a cloud, yet if they wereboth on the surface how could one travel faster over the same path?
Very soon the white circle passed entirely across the greater orb, andthen I was surprised to see it detach itself from the planet and remainfor a few moments as a separate small orb in the sky! Could this beanother freak of refraction? But before I could determine, the littleorb disappeared behind the greater disc and was gone. The greenish spot,which I judged to be truly on the surface and caused by an ocean orgreat sea, was about three times as long in crossing the disc. I nextturned my attention to the immovable and irregular white spot, anddiscovered that its edges seemed to be revolving slowly around itscentre. Then it occurred to me that this spot must be located at one ofthe poles and be caused by polar ice and snows. The doctor had expectedsuch on Mars, and I no longer doubted that this was our objectiveplanet.
It was like a great holiday for me when the doctor regainedconsciousness. Almost as soon as his fever abated he was well enough toperform his customary duties. His illness had not made him appreciablyweak, because as yet scarcely any effort was required to move about. Hewas quite as anxious to hear all my experiences as I was eager torelate them. I gave him a full account of my struggle passing thedead-line, of my discovery of Mars, and the various spots I had noted.
"From the time it took the greenish spot to cross, I should judge aMartian day to be about fifty hours long," I said.
"Then you _must_ have been very lonely," he replied. "For a Martian dayis just forty-one minutes longer than an Earthly day, unless a greatnumber of our scientists have continually made the same mistake inobserving him."
"When we arrive, we shall be able to determine the point exactly if ourwatches commence running again," I answered. "But I think I know onereason why I have misjudged the time. Ever since you have been ill Ihave slept very little. I have hardly felt the need of rest since I lostmy weight. I have been growing more and more wakeful, and I rarely sleepmore than an hour at a time. That seems quite sufficient to refresh me."
"As we regain our weight we shall feel the need of sleep again," hesaid. "But on Mars we may need but one-third as much as we had on Earth,unless we exert ourselves proportionately more."
Then I told him about the circular spot which had seemed to slip off theupper edge of Mars, and asked his explanation of it.
"That must have been Phobos, one of the moons of Mars," he said.
"One of his moons!" I exclaimed; "I didn't know he had _any_."
"You are an American, and say that!" he answered in surprise. "It is oneof the astronomical glories of your people that they discovered the twomoons of Mars, during the favourable opposition of 1877."
"This is the first case I remember where we have left it to a foreignerto tell us how great we have been!" I laughed.
"These two moons of Mars also furnish a most interesting example of howfiction may forestall and pre-figure actual scientific discovery. Dr.Swift made Gulliver, in his wonderful travels, discover two moons ofMars, revolving at a speed which he must have thought ridiculously fast.Many years afterward the American telescopes really found two moons, butactually revolving more rapidly than Dr. Swift had dared to boast! Ifyour white circle was really Phobos, you have seen the freak amongsatellites. She is the smallest, swiftest moon ever discovered, andtravels so much more swiftly than the revolution of her primary that sheappears to go opposite to everything else in the Martian sky, risingwhere the Sun sets and crossing the heavens from west to east!"
"What I saw did travel in the same direction as the rotation of theplanet, and much more rapidly," I exclaimed.
"Then it was Phobos without a doubt, and she is due to appear again inthe west in three hours and fifty minutes after she sets in the east. Wemust watch closely, for I wish to land upon her and make a flying tripall around Mars with her. Do you realize what a glorious view we shallhave of the great planet, sailing around him on this satellite in aperiod of a little over seven and a half hours, and at a distance ofonly about four thousand miles? There will be no night, for if one sideof the little moon is heavier than the other, the heavier side willalways be turned toward Mars. Therefore, when the Sun does not shine onPhobos, Mars will do so, and keep her continually illuminated, exceptfor the brief period of the r
egular eclipse during each revolution. Andone-fourth of the entire heavens, as seen from Phobos, will be filledwith the glowing orb of Mars! The great planet will exhibit to us at anear range all the configurations of his surface, his oceans and hisclouds. We will survey and photograph him to our hearts' content."
The doctor was justly enthusiastic on this subject, and I felt that sucha landing would, in some measure, compensate for my disappointment innot being able to visit the Moon.
As I watched carefully, the satellite finally came into view, but verymuch more distant from Mars than before. Also, it moved very slowly now,and seemed to grow larger as it approached the disc. I pointed it out tothe doctor, and remarked that it was acting quite differently. Just asit entered upon the orb of Mars, another moon, somewhat smaller, mountedhurriedly from the under side of the planet and began hastily ploughingher way over the ruddy disc.
"That last one is the one I saw before, that is my Phobos!" I criedexcitedly.
"Then the other slow one is Deimos, the outer moon. She appears thelarger to us now, because her greater distance from Mars makes hernearer to us, but she appears to the Martians as the smaller. We mustobserve closely, and we may discover some new and lesser satelliteswhich Earthly telescopes have never found."
"Time enough for that when we land on Mars," I answered. "If we get inpast these two without being hit, I shall be satisfied. You dare notventure in front of that Phobos, and I don't see how you can everovertake her if you approach from behind."
"That reminds me to slacken speed, for we must be getting very near," hesaid. "Please weigh yourself every few minutes and note your increasingweight. You should weigh seventy-two pounds on Mars, and eight pounds atthe distance of Phobos."
He immediately reversed currents, and when I reported that I weighedalmost a pound, it frightened him, and he turned in the full power ofthe negative currents to overcome our momentum. And it proved that therepelling power of Mars at the distance of 15,000 miles, which thisindicated, was not at all strong against the great velocity we had beendaily acquiring. I hung upon the scales every few minutes, and reporteda steadily increasing weight up to three pounds.
"That shows a distance of eight thousand miles," he figured. "Almostexactly in the orbit of Deimos, but she has safely passed, and will notreturn for thirty hours. We must turn the rudder hard over to the right,and sail around the planet in a circle until Phobos overtakes us; then,if we approach her travelling in the same direction at almost the samerate of speed, her gravitational attraction will pick us up and draw ussafely ashore."
Mars was already an enormous orb ahead of us, and many of his features,such as oceans, ice-caps, and continents, could easily be distinguished;but we paid little attention to them, being occupied with making a safelanding on Phobos, and expecting to make a systematic study of him fromthere.
"We must not attempt a landing on the outer side of the satellite," thedoctor reflected, "for we should have no way of getting around to theinner side to make our observations. We must go within her orbit, andthen as she comes past allow her attraction to draw us gently towardher."
We had quickly overtaken and passed Deimos, far within her orbit. I waskeeping a close watch for Phobos out of the rear window as we circledabout Mars at a distance which we calculated, from my weight on thescales, must be within the path of the satellite. We were circling inthe same direction that the great planet was rotating, and yet we passedby things on his surface, which proved that we were travelling fasterthan his rotation. The doctor noticed, with his telescope, a brilliantsnow-capped peak of a great mountain towering up from a small island.The contrast of the snow peak, with the darkish green waters all aroundit, was the most pronounced thing visible on the great planet, and hedecided this must be the white spot detached from the polar ice whichour astronomers have frequently observed at about twenty-five degreessouth latitude, and to which they have given the name Hall's Island.
"I am afraid we have not appreciated the speed at which we have beentravelling," remarked the doctor. "Phobos is very slow in overtakingus;" and he was just beginning to slacken speed still more, when hesuddenly cried out,--
"Here she is ahead of us now! We have overtaken her, instead of waitingfor her to catch us!"
And, true enough, we were gradually approaching a small brownish mass,feebly illuminated on its outer half by the sun, and more faintly stillon its inner half by reflected light from Mars.
And how shall I describe that queer little toy-world which we weregradually overtaking? Imagine, if you can, a little island, less than athird the size of the Isle of Wight, tossed a few thousand miles intospace, and circling there rapidly to avoid falling back upon the greatersphere. Imagine that flying island devoid of soil, of trees orvegetation, of water or air, of everything but barren, uncrumbled,homogeneous rock, and you have some idea of the unadorned desolation ofPhobos, into which we were slowly sailing, or falling. There was noteven the slightest trace of sand or scraps of rock, such as time musthave abraded from even the hardest surfaces, but the reason for thissoon became apparent.
The doctor feared steering directly against her as we approached, lestwe should land with a crash. We had already reached her and weretravelling along her inner side. Although we were very near her, sheseemed to have very little attraction for us. Then he turned very muchcloser, but as soon as the influence of the rudder was released, weseemed to leave her instead of falling upon her as we expected. We werestill travelling faster than she was, and had we steered directlyagainst her, we would have crashed and bumped against her protuberances.Still there seemed to be no other way to make a landing. In order toestimate the amount of such a shock, the doctor calculated, from thebest information he had of her size and a guess at her density, that shewould attract the projectile and its entire load with a force of onlytwo pounds. That was not enough to cause any very great shock, and hedecided to take chances at once, before we had entirely passed her. Heturned the rudder hard over toward the satellite, and we came againsther with scarcely any crash, but with a bumping and grating thatcontinued until the rudder was eased back. Then, to our great surprise,we did not remain on the surface, but rose from it and sailed inwardtowards Mars.
"Something wrong here!" exclaimed the doctor. "She has no attraction forus."
"Well, how do you explain this?" I asked. "You say the whole projectileweighs only two pounds toward Phobos, when, just a short time ago, Iweighed nearly eight pounds myself on the scales."
"True enough!" he cried; "the gravity of Mars must be dominant." Hebegan figuring rapidly, and then exclaimed: "We weigh one hundred andthirty pounds toward Mars, and only two pounds toward the satellite.Small wonder that we could not make a landing, with Mars pulling us awaysixty-five times harder than Phobos attracted us! But this is verystrange! I remember no mention of this in any of the astronomicalwritings, and it is as easily calculable on Earth as it is here.Moreover, this must cause everything that is loose upon Phobos to fallupon Mars. The great planet is tugging at everything the satellite haswith a force sixty-five times stronger than her own!"
"Now, I am afraid those figures won't do, Doctor," I put in. "For, ifwhat you say is true, what prevents the whole satellite from tumblinginto Mars at once?"
"She would do so were it not for centrifugal force. The speed with whichshe whirls around the planet must just balance the force with which heattracts her, and thus she is kept in her orbit. But stones and loosethings on this side of her centre are attracted more strongly by Marsthan they are repelled by the whirling, so they must all have fallen tothe planet. That is why the surface was perfectly barren. If Phobosalways keeps the same side turned toward Mars, there may be rocks andsoil on the outer side, and we could land there with a positive current;but we could not see the great planet, as I had hoped."
"I have had quite enough of this moon-chasing," I said; "let us be offfor the large game at once!" and the doctor agreeing, we turned directlytoward Mars.
BOOK II
Other Worl
d Life