QUÆRENS: What an extraordinary discovery for an analytical mind like yours, dear Lumen! By what means did you satisfy yourself that your conclusions were correct?
LUMEN: While I was gradually arriving at the conviction of which I have told you, the old men around me on the mountain continued their conversation. Suddenly the oldest of them, a veritable Nestor whose aspect commanded both admiration and respect, called out, in a loud and mournful voice "On your knees, my brethren; let us pray for forbearance to the universal God.
That world, that nation, that city continues to revel in blood. A fresh head, that of a king this time, is about to fall." His companions seemed to understand, for they knelt down on the mountain, and prostrated their white faces to the ground. For myself, I had not yet succeeded in distinguishing men in the streets and squares of Paris, and not being able to verify the observations of these old men, I remained standing, but I pursued my examination of the scene before me carefully. "Stranger," said the old man to me, "do you blame the action of your brothers since you do not join your prayers to theirs?" "Senator," I replied, "I neither approve nor blame what I do not comprehend. Having only just arrived on this mountain, I do not know the cause of your righteous indignation." I then drew near the old man, and while his companions were rising and entering into conversation in groups, I asked him to describe the situation to me.
The French Terror visible in Capella.
He informed me that the order of spirits inhabiting this world are gifted by intuition with the power of seeing and apprehending events in the neighbouring worlds, and that they each possess a sort of magnetic relation with the stars and systems around them. These neighbour-worlds, or stars, are twelve or fifteen in number. Outside that limit the perceptions become confused. They have therefore a vague but distinct knowledge of the state of humanity in the planets of our Sun, and of the relative elevation in the intellectual and moral order of their inhabitants. Moreover, when a great disturbance takes place, either in the physical or the moral realm, they feel a sort of inner agitation, like that of a musical chord which vibrates in unison with another chord at a distance.
Old men in Capella watch the doings on the Earth.
For a year (a year of this world is equal to ten of our years) they had felt themselves drawn by special attraction towards the terrestrial planet, and had observed with unusual interest and anxiety the march of events in that world. They had beheld the end of a reign and the dawn of glorious liberty, the conquest of the rights of man and the assertion of the great principles of human dignity. Then they had seen the cause sacred to liberty placed in peril by those who should have been the first to defend it, and brute force substituted for reason and justice.
I saw that he was describing the great Revolution of 1789, and the fall of the old political world before the new régime. Very mournfully they had followed the events of the Reign of Terror and the tyranny of that bloody time. They trembled for the future of the Earth, and felt doubtful of the progress of a humanity which, when emancipated, so soon lost the treasure it had just acquired. I took care not to let the senator know that I had just arrived from the Earth myself, and that I had lived there seventy-two years. I do not know whether he was aware of this, but I was so much surprised by this vision before me that it completely absorbed my mind and I did not think of myself.
At last my sight was fully developed, and I perceived the spectacle in all its details. I could distinguish, in the midst of the Place de la Concorde, a scaffold, surrounded by a formidable array of war, drums, cannon, and a motley crowd armed with pikes. A cart, led by a man in red, bore the remains of Louis XVI. in the direction of the Faubourg St. Honoré. An intoxicated mob lifted their fists to heaven. Some horsemen, sabre in hand, mournfully followed. Towards the Champs-Élysées there were ditches into which the curious stumbled. But the agitation was concentrated in this region. It did not extend into the town, which appeared dead and deserted; the terror had thrown it into a state of lethargy.
Lumen witnesses the scenes of the French Revolution.
I was not present during the events of 1793, since that was the year of my birth, and I felt an inexpressible interest in being thus a witness of these scenes of which I had read in history. I have often discussed and debated the vote of the Convention, but I confess to you I see no excuse of state in the execution of such men as Lavoisier, the creator of chemistry, Bailly, the historian of astronomy, André Chenier, the sweet poet, or the condemnation of Condorcet, the philosopher. These have roused my indignation much more than the punishment of Louis XVI. I was intensely interested at being thus a witness of this vanished epoch. But you may imagine how much greater was my surprise, and how much more I was astonished, that I beheld in 1864 events actually present before me which had taken place at the end of the last century.
QUÆRENS: In truth, it seems to me that this feeling of its impossibility ought to have awakened doubt in you. Visions are essentially illusory. We cannot admit their reality even though we see them.
LUMEN: Yes, my friend, it was as you say, impossible! Now can you understand my experience in seeing with my own eyes this paradox realised? The common saying is, "One cannot believe one's own eyes.'' That was just my position. It was impossible to deny what I saw, and equally impossible to admit it.
QUÆRENS: But was it not a conception of your own mind, a creation of your imagination, or perhaps a reminiscence of your memory? Are you sure it was a reality, not a strange reflection from your memory?
LUMEN: That was my first idea; but it was so obvious that I saw before me the Paris of '93, and the events of January 21, that I could no longer be in any doubt about it. Besides, this explanation was anticipated by the fact that the old men of the mountain had preceded me in observing these phenomena, and they had seen, and analysed, and conversed on them as actual facts without knowing anything of the history of our world, and were quite unaware of my knowledge of that history. Further, we had before our eyes a present fact, not a past event.
Not a paradox.
QUÆRENS: But, on the other hand, if the past can be thus merged into the present, if reality and vision can be allied in this way, if persons long since dead can be seen again acting on the scene of life, if new structures and metamorphoses in a city like Paris can disappear and give place to the aspect of the city as it was formerly--in short, if the present can vanish and the past be re-created, what certainty can we have of anything? What becomes of the science of observation? What becomes of deductions and theories? On what solid foundation can we base our knowledge? If these things are true, ought we not henceforth to doubt everything, or else to believe everything?
LUMEN: Yes, my friend, these considerations and many others occupied my mind and tormented me, but they did not do away with the reality which I was observing.
When I had assured myself that we had present before our eyes the events of the year 1793, it immediately occurred to me that science, instead of conflicting with these facts, ought to furnish an explanation of them, for two truths can never be opposed to one another. I investigated the physical laws, and I discovered the solution of the mystery.
QUÆRENS: What! the facts were real?
LUMEN: They were not only real, but comprehensible and capable of demonstration. You shall have an astronomical explanation of them. In the first place, I examined the position of the Earth in the constellation of the Altar as I have told you; I took the bearings of my position relatively to the Polar star and to the Zodiac. I remarked that the constellations were not very different from those we see from the Earth, and that except in the case of a few particular stars, their positions were evidently the same. Orion still reigned in the ultra-equatorial region, the Great Bear pursuing his circular course still pointing to the north. In comparing the apparent movements, and co-ordinating them scientifically, I calculated that the point where I saw the group of the Sun, the Earth, and the planets, marked the 17th hour of right ascension, that is to say, about the 256th degree, or nearly so. I had no instrument to take exact measurements.
Explanation of the apparant paradox.
I observed, in the second place, that it was on the 44th degree from the South Pole. I made these observations to ascertain the star on which I then was, and I was led to conclude that I was on a star situated on the 76th degree of right ascension, and the 46th degree of north declination. On the other hand, I knew from the words of the old man that the star on which we were was not far from our Sun, since he considered it to be one of the neighbouring stars. From these data I had no difficulty in recalling the star that stands in the position I had determined. One only answered to it, that of the first magnitude, Alpha in the constellation of Auriga, named also Capella, or the Goat.
Lumen acertains the place where he was in space.
There was no doubt about this. Thus I was certain that I was on one of the planetary worlds of the sun Capella. From thence our Sun looks like a simple star, and appears in perspective to be in the constellation of the Altar, just opposite that of Auriga, as seen from the Earth.
Then I tried to remember what was the parallax of this star. I recalled that a friend of mine, a Russian astronomer, had made a calculation, which had been confirmed, of this parallax. It was proved to be 0,"046.--When I had thus solved the mystery my heart beat with joy. Every geometrician knows that parallax indicates mathematically the distance in units of the magnitude employed in the calculation. I sought then to recall exactly the distance which separated this star from the Earth, in order to prove the accuracy of the calculation. I only needed to find out what number corresponded to 0,"046. 
Expressed in millions of leagues, this number is 170,392,000, and so, from the star on which I was, the Earth was distant 170 billions 392 thousand millions of leagues. The principle was thus established, and the problem was three parts solved. Now, here is the main point, to which I call your special attention, for you will find in it an explanation of the most marvellous realities.
Light, you know, does not cross instantaneously from one place to another, but in successive waves. If you throw a stone into a pool of tranquil water, a series of undulations form around the point where the stone fell. In the same way, sound undulates in the air when passing from one point to another, and thus, also, light travels in space--it is transmitted in successive undulations. The light of a star takes a certain time to reach the Earth, and this time naturally depends on the distance which separates the star from the Earth.
The velocity of light.
Sound travels 340 metres in a second. A cannon shot is heard immediately by those who fire it, a second later by persons who are at a distance of 340 metres, in three seconds by those who are a kilometre off, twelve seconds after the shot at four kilometres. It takes two minutes to reach those who are ten times farther off, and those who live at a distance of a hundred kilometres hear this human thunder in five minutes. Light travels with much greater swiftness, but it is not transmitted instantaneously, as the ancients supposed. It travels at the rate of 300,000 kilometres per second, and if it could revolve, might encircle the Earth eight times in a second. Light occupies one second and a quarter to come from the Moon to the Earth, eight minutes and thirteen seconds to come from the Sun, forty-two minutes to come from Jupiter, two hours to come from Uranus, and four hours to come from Neptune.
Therefore, we see the heavenly bodies not as they are at the moment we observe them, but as they were when the luminous ray which reaches us left them. If a volcano were to burst forth in eruption on one of the worlds I have named, we should not see the flames in the Moon till a second and a quarter had elapsed, if in Jupiter not till forty-two minutes, in Uranus two hours after, and we should not see it in Neptune till four hours after the eruption. The distances are incomparably more vast outside our planetary system, and the light is still longer in reaching us. Thus, a luminous ray coming from the star nearest to us, Alpha, in Centaurus, takes four years in coming. A ray from Sirius is nearly ten years in crossing the abyss which separates us from that sun. The star Capella, being the distance above mentioned from the Earth, it is easy to calculate, at the rate of 300,000 kilometres the second, what time is needed to cross this distance.
How the heavenly bodies are seen.
The calculation amounts to seventy-one years, eight months, and twenty-four days. The luminous ray, therefore, which came from Capella to the Earth, traversed space without interruption seventy-one years, eight months, and twenty-four days before it was visible on the Earth. In like manner, the ray of light which leaves the Earth can only arrive at Capella in the same period of time.
Time occupied in the transmission of light.
QUÆRENS: If the luminous ray which comes from that star takes nearly seventy-two years to reach us, it follows that we see the star as it was nearly seventy-two years ago?
LUMEN: You are quite right, and this is the fact that I want you take note of specially.
QUÆRENS: In other words, the ray of light is like a courier who brings despatches from a distant country, and having been nearly seventy-two years on the way, his news is of events that occurred at the time of his departure seventy-two years ago.
A belated courier.
LUMEN: You have divined the mystery. Your illustration shows me that you have lifted the veil which shrouded it. In order to be still more exact, the light represents a courier who brings, not written news, but photographs, or, strictly speaking, the real aspect of the country from whence he came. We see this living picture such as it appeared, in all its aspects, at the moment when the luminous rays shot forth from the distant orb. Nothing is more simple, nothing more indubitable. When we examine the surface of a star with a telescope we see, not the actual surface as it was at the time of our observation, but such as it was when the light was emitted from that surface.
QUÆRENS: This being so, if a star, the light of which takes ten years to reach us, were to be annihilated to-day, we should continue to see it for ten years, since its last ray would not reach us before ten years had elapsed.
LUMEN: It is precisely so. In short, the rays of light that proceed from the stars do not reach us instantaneously, but occupy a certain time in crossing the distance which separates us from them, and show us those stars not as they are now, but such as they were at the moment in which those rays set out to transmit the aspect of the stars to us. Thus we behold a wondrous transformation of the past into the present.
In the star we observe we see the past, which has already disappeared, while to the observer it is the present, the actual. Strictly speaking, the past of the star is positively the present of the observer. As the aspect of the worlds change from year to year, almost from day to day, one can imagine these aspects emerging into space and advancing into the infinite, and thus revealing their phases in the sight of far-distant spectators. Each aspect or appearance is followed by another, and so on in endless sequence. Thus a series of undulations bears from afar the past history of the worlds which the observer sees in its various phases as they successively reach him. The events which we see in the stars at present are already past, and that which is actually happening there we cannot as yet see. Realise to yourself, my friend, this presentation of an actual fact, for it is of importance to you to comprehend the precession of the waves of light and to understand the essential nature of this undoubted truth. The appearance of things, borne to us by light, shows us those things not as they are at present, but as they were in that period of the past which preceded the interval of time needed for the light to traverse the distance which separates us from those events.
We see the past, not the present, aspect of the stars.
We do not see any of the stars such as they are, but such as they were when the luminous rays that reach us left them.
It is not the actual condition of the heavens that is visible, but their past history. Moreover, there are distant stars which have been extinct for ten thousand years, but which we can see still, because the rays of light from them had set out before they were extinguished. Some of the double stars, the nature and movements of which we seek with care and toil, ceased to exist long before astronomers began to make observations. If the visible heavens were to be annihilated to-day we should still see stars to-morrow, even next year, and for a hundred years, a thousand years, and even for fifty and a hundred thousand years, or more, with the exception only of the nearest stars, which would disappear successively as the time needed for their luminous rays to reach us expired. Alpha of Centaur would go out first, in four years, Sirius in ten years, and so on.
The planet Earth as seen from afar.
Now, my friend, you can easily apply a scientific theory in explanation of these strange facts of which I was witness. If from the Earth one sees the star Capella, not as it is at the moment of observation, but as it was seventy-two years before, in the same way from Capella one would see the Earth as it was seventy-two years earlier, for light takes the same time to traverse the distance either way.
QUÆRENS: Master, I have followed your explanation attentively. But, I ask you, does the Earth shine like a star? Surely she is not luminous?
LUMEN: She reflects in space the light of the Sun; the greater the distance the more our planet resembles a star. All the light that radiates from the Sun on its surface is condensed into a disc that becomes smaller and smaller. Seen from the Moon our Earth appears fourteen times more luminous than the full Moon, because she is fourteen times larger than the Moon. Seen from the planet Venus the Earth appears as bright as Jupiter appears to us. From the planet Mars the Earth is the morning and the evening star, presenting phases like those of Venus to us.
The other planets seen from afar.
Thus, although our Earth is not luminous herself, she shines afar like the Moon and the planets, by the light that she receives from the Sun, and reflects into space.
Now the events taking place on Neptune, if seen from the Earth, would have a delay of four hours; in like manner the view of life on the Earth could only reach Neptune in the same time; nearly seventy-two years, therefore, separate Capella and the Earth.
QUÆRENS: Although these views are new and strange to me, I now understand perfectly how, since the light was nearly seventy-two years in traversing the abyss which separates the Earth from Capella, you beheld not the Earth as it was in October 1864, the date of your death, but as it appeared in January 1793. And I comprehend quite as clearly that what you saw was neither a phenomenon of memory, nor a supernatural experience, but an actual, positive, and incontestable fact, and that in very truth what had long passed away on the Earth was only then present to an observer at that distance. But permit me to ask you an incidental question. In coming from the Earth to Capella did you cross that distance even more quickly than light?
LUMEN: Have I not already anticipated your question in telling you that I crossed this distance with the swiftness of thought. On the very day of my death I found myself on this star, which I had admired and loved so much all my life on the terrestrial globe.
Thought swifter than light.
QUÆRENS: Ah, Master, although everything is thus explained, your vision is not the less wonderful. Truly it is an astonishing phenomenon that of seeing thus at once the past in the present in this extraordinary manner. Not less marvellous is the thought of seeing the stars, not such as they are when one makes the observation, nor as they have been simultaneously, but as they have been at different epochs according to their distances, and the time that the light of each has taken in coming to the Earth!
LUMEN: I venture to say that the natural astonishment that you feel in contemplating this truth is only the prelude to the things which I have now to unfold to you. Undoubtedly, it appears at first sight very extraordinary, that by removing to a distance in space, one can become a witness of long past events, and remount as it were the stream of time. But this is not more strange than what I have yet to communicate to you, and which will appear to you still more imaginary if you can listen a little longer to the narrative of that day which followed my death.
QUÆRENS: Go on, I beg of you, I am eager to hear you.
 Every one knows that the farther an object is, the smaller it appears. An object which is seen under an angle of one second, is at a distance of 206,265 times its own diameter, whatever it may be; because as there are 1,296,000 seconds in the circumference, the ratio between the circumference and its diameter being 3,14159 x 2, it follows that this object is at a distance equal to 206,265 times its own diameter. As Capella sees the semi-diameter of the terrestrial orbit only under an angle 22 times smaller, its distance is 22 times greater. Capella is therefore at a distance of 4,484,000 times the radius of the terrestrial orbit. Future micrometrical measurements may modify these results concerning the parallax of this star, but they cannot change the principle upon which the conception of this world is grounded.