Algol

“ And this is really the explanation of the strange changes in the brightness of Algol, for such a dark body as we are imagining does in reality exist. It is a large dark body, very nearly as large as Algol himself, and if, as we may conjecture, it is a mighty planet, we have the extraordinary example of a planet and its sun being nearly the same size. ”

“ It hardly needs to be said that the dark body in question, if it exists, must be of enormous size, bearing no such insignificant proportion to the size of Algol as the earth does to the sun, but being rather the rival in bulk of its shining brother—a blind companion, an extinguished sun. ”

“ It is worth making the attempt, because, as we have already said, Algol is the first star among "yonder hundred million spheres" of which the dimensions are approximately known. First we are to think of Algol itself. It is indeed a vast object, a glowing globe, a veritable sun, much larger than our own. The diameter of the sun would have to be increased by almost 200,000 miles to make it as great as that of Algol. But we may exhibit the relative proportions of the two bodies in a somewhat different manner. Imagine two globes, each as large as our sun ”

“ The scale on which it varies in brightness is very [Pg 309] great, for it changes from the second to the ninth magnitude. For the other leading type of variable star, Algol, of which mention has already been made, is the best instance. The shortness of the period in which the changes of brightness in such stars go their round, is the chief characteristic of this latter class. The period of Algol is a little under three days. This star when at its brightest is of about the second magnitude, and when least bright is reduced to below the third magnitude ”

“ The revolution of Algol seems to approach the nearest to a fact in favor of a star being the centre of a revolving system; and from the first, as we have said, the periodical change, and the sudden darkening and brightening of this luminary, suggested the supposition of an opaque body revolving about it. But this body cannot be a planet. The planets which revolve about our Sun are not, any of them, nor all of them together, large enough to produce a perceptible obscuration of his light, to a spectator outside the system. But in Algol, the phenomena are very different from this. ”

“ In accordance with the eclipse theory to account for the variations of light in Algol, it has been proved that this star is accompanied by a great dark satellite as large as our sun, which at regular intervals passes between us and Algol, cutting off a portion of its light. Algol is said to be one million miles in diameter, while the diameter of the satellite is given as eight hundred thousand miles. The distance between these enormous bodies is three million miles. ”

“ In this way it has been discovered that an Algol star is revolving round an invisible companion, for it alternately approaches and recedes, and these movements correspond with its light-changes. It is, in fact, a spectroscopic binary which happens to have an orbit whose plane lies just in our line of sight, so that at every revolution one star passes behind the other. ”

“ As the first illustration of the extraordinary results that are now being obtained by the application of the new process, I take the case of the celebrated variable Algol. This star is a well-known object to all star-gazers; it lies in the constellation of Perseus, and its vagaries attracted notice in early times. In ages when the stars were worshipped as divinities it is not unreasonable to suppose that a star whose light varied in any extraordinary manner should naturally be viewed with some degree of suspicion as contrasted with stars that dispense their beams with uniformity. ”

“ According to it, Algol possesses a companion as large as the sun, but invisible, both because of its proximity to that star and because it yields no light, and revolving in a plane horizontal to our line of sight. The period of revolution is identical with the period of Algol's cycle of variation, and the diminution of light is caused by the interposition of the dark body as it sweeps along that part of its orbit lying between our point of view and the disk of Algol. ”

“ The diameter of Algol is believed to be about 1,125,000 miles, that of the dark body about 840,000 miles, and the mean distance from center to center 3,230,000 miles. The density of both the light and the dark star is slight compared with that of the sun, so that their combined mass is only two thirds as great as the sun's. ”

“ Since the companion of Algol is often spoken of as a dark body, it were well here to point out that [Pg 310] we have no evidence at all that it is entirely devoid of light. We have already found, in dealing with spectroscopic binaries, that when one of the component stars is below a certain magnitude [33] its spectrum will not be seen; so one is left in the glorious uncertainty as to whether the body in question is absolutely dark, or darkish, or faint, or indeed only just out of range of the spectroscope. ”

“ At this distance Algol, as observed from the planet, will fill half the sky, and the heat he gives out must be something stupendous. Also the effects of gravitation must be queer indeed, acting on two such huge bodies so close together. If any beings live in such a strange world, the pull which draws them to their mighty sun must be very nearly equal to the pull which holds them to their own globe ”

“ There are known at present twenty-two variables of the Algol type, that is, stars having each a dark companion very close to it which obscures it either wholly or partially during every revolution. In these cases the density of the systems can be approximately determined, and they are found to be, on the average, only one-fifth that of water, or one-eighth that of our sun. But as many of them are as large as our sun, or even considerably larger, it is evident that they must be wholly gaseous, and, even if very hot, of a less complex constitution than our luminary. ”

“ We have, indeed, a suspicion of at least one, though perhaps it partakes rather of a planetary nature, namely, that "dark" body which continually eclipses Algol, and so causes the temporary diminution of its light. ”

“ Of course, no optical instrument whatever is needed to enable one to see these changes of Algol for it is plainly visible to the naked eye throughout, but it will be found interesting to watch the star with an opera-glass. Its periodic time from minimum to minimum is two days, twenty hours, and forty-nine minutes, lacking a few seconds. Any one can calculate future minima for himself by adding the periodic time above given to the time of any observed minimum. ”

“ Algiers has a special atmosphere all its own. It lacks those little graces which we identify as thoroughly French, in spite of the fact that the city itself has become so largely Frenchified; and it lacks to a very great extent—from almost every view-point—that Oriental flavour which one finds at Cairo and Tunis. But for all that, Algiers is the most wonderful exotic and conventional blend of things Arab and European on top of earth.
The environs of Algiers are rugged and full of character, opening out here and there into charming distant vistas, and wide panoramas of land and sea and sky. ”

“ Algiers is such a city of contrasts, of dark memories and present prosperity, of Christian slavery and Christian rule, brilliant sun and tropical rain, of wide modern streets and networks of narrow alleys, with the slow dignity of movement of the old race and the rapid vivacity of their new rulers, that it makes all the difference in the world in what spirit and at what moment you arrive. At times the city is all sunshine, “a diamond in an emerald frame,” as the Arabs call it; at others only a dim outline is visible blotted out by the tropical rain. ”

“ His first impressions of Algiers, rising out of the Mediterranean like a white bubble in a sea of sapphire, will be the best he will have of this once Turkish city, now a vast commercial town and only a little less noisy than Marseilles. The sight of the Arab quarter, piling itself up in a pyramid of white and blue roofs above the European houses, with the fresh gardens of Mustapha away to the left and the Turkish forts in the foreground, is a vision of delight. ”

“ The woman returned to Ogul without having found the basilisk. Zadig was introduced to this mighty lord and spoke to him in the following terms: “May immortal health descend from heaven to bless all thy days! I am a physician; at the first report of thy indisposition I flew to thy castle and have now brought thee a basilisk stewed in rose water. Not that I pretend to marry thee. All I ask is the liberty of a Babylonian slave, who hath been in thy possession for a few days; and, if I should not be so happy as to cure thee, magnificent Lord Ogul, I consent to remain a slave in her place.” ”

“ A plentiful spring of water gushes out of a rock close by, and tumbles down the hill on its way to the sea; so that nothing is wanting20 to the enjoyment of an inhabitant of the south. The house stands under Mustapha Superieur and affords a magnificent view over the sea and the bay of Algiers. On this spot some dozen Turks and Arabs dream away the greater part of their lives. The owner of the café is an old Turk who formerly served among the mamelukes of the Dey. He passed some years of his life a prisoner in Spain, where, besides corrupt and broken Spanish, he learned to drink and swear. ”

“ If the weather is fine it is strongly recommended that one stay until the sunset, as the spectacle of the sun disappearing behind the hills of Algiers, making of it a great brazier of flame, compensates one for the drive back in the dusk. But really to appreciate Laperouse it must be visited on a summer day. The heavy atmosphere of Algiers is left behind, and one finds oneself in a sea of light and freshness. The water lazily laps the cliffs and ripples up on the golden sand. ”

“ His women are mere beasts of burden, absolutely at the mercy of their lord. A whole world of progress lies between the Frenchman who works his fingers to the bone to give his daughter a dower, and the Arab who sells his to the highest bidder. And in love as in life the Arab is often a nomad, as the desert towns bear witness. But as he stalks haughtily through the streets of Algiers, he is an attractive and interesting figure. ”

“ How much more real Algiers was than the rock on the Rigi where we sat, or the lake beneath, or the mountains beyond. Algiers is very real, though I have never seen it, and my friend is my friend for ever, though I have lost his card and forgotten his name. ”

“ You may see here, as often you may see in Cairo and the cities of the East, a tradesman 156seated in his little shop poring over an Arab text. In Algeria generally the standard of education among the natives is very low; only a small fraction of one per cent can read and write. The religion of the Tlemçen Arabs is naturally of a somewhat higher type than that of those who, knowing nothing of the law and the prophets, are content with the observance of fast days and a cult of saints mixed with all sorts of survivals of fetishism. ”

“ The fortifications of Algiers were barriers which separated the growing civilization of Europe from the barbarian nether world, and they{256} fell only with the coming of the French in the second quarter of the nineteenth century. Such is the story of the entering wedge of progressive civilization in Algeria.
Algiers’ veiled women are one of the city’s chief and most curious sights for the stranger within her walls. On Friday, the jour des morts of the Arab women, they go to the cemetery to weep or to make gay, according as the mood is on. ”

“ Hemmed in between the Atlas Mountains and the Great Sahara, it forms the real Algerian hinterland, a region vastly different in people, manners, and customs from either the desert or the littoral. Here, in this fertile borderland, where the red tarbooshes and baggy trousers of the French outposts are the sole signs of civilisation, is the home of the Ouled-Naïls, that curious race, neither Arab, Berber, nor Moor, the beauty of whose dusky, daring daughters is a staple topic of conversation in every harem and native coffee-house between the Pyramids and the Pillars of Hercules. ”

“ Then for a change, just by crossing a road, there is a real oasis of ordinary palms, making a delicious shade for the little tables of two bright cafés; and from this spot, at the water’s very edge, is a peep of old Algiers, the “white city,” the harbour and the boats glowing in the soft afternoon light, and reflected in the calm opalescent water. ”

“ Their women are not veiled, and occupy a much more independent position than is usual in Mohammedan countries. Their men, to be seen in the streets of Algiers, may frequently be distinguished from the Arabs by their fair complexions, blue eyes and reddish hair. They have no inclination to a nomad life, and are naturally industrious, freely offering their labour to the French colonists. They would seem to present a more likely field for the spread of social progress according to European ideas than does the lazy indifference of the Arab; but in their case, too, religion is a bar. ”

“ Far to the west, beyond Oran, and close to the frontiers of Morocco, lies a hill city, once the seat of empire and of learning, but now sunk to the condition of a provincial town. Yet Tlemçen has occupied so high a position in the Mohammedan world, and the reputation of its existing monuments is so widespread, that the enterprising traveller will desire to visit it. The distance from Algiers is great, some 800 miles there and back, and as there is little of interest on the road, a journey by motor-car is not inviting. ”