O Our observation of the celestial phenomena may most easily be made in the winter-time. Then the nights are long, and the vault of heaven is crowded with stars, and, unilluminated by the moon, exhibits all its splendours. In the other seasons of the year, and particularly in summer, the twilight gleam encroaches, so to speak, upon a portion of the nights, which are otherwise so brief, and precludes our vision from any exact estimate of the stars. Those demitints, those soft subdued reflections of light, scarcely permit the eye to distinguish even stars of the first and second magnitude, which shine like spots of dull gold on a background of pale silver.

The Number of the Stars.

How many are the stars?

To such a question comes the immediate answer, They are infinite in number.

But, after a little meditation, we begin to perceive that the question, apparently so simple, is, in reality, one of very great complexity. Let us endeavour to disentangle its various threads.

We must not forget that, in every scientific analysis, it is important we should, in the first place, separate two intimately united elements,—the individual who observes, and the product of the observation. The former, the "sensorial factor," is subject to every condition of space and time; the second, the "intellectual factor," tends, by its generalisations, to free itself from those very conditions which are the inseparable co-efficients of matter and movement. The individual passes; save from an outer standpoint, we know not whence he comes, nor whither he goes. The product of the observation remains; transmissible from generation to generation, it will gradually expand and increase, if it be founded upon truth; but, on the contrary, its splendour will wane, and will eventually disappear, if it be founded upon error. Eternal is this spectacle of actors and puppets succeeding one another uninterruptedly upon the same stage! As one falls, another steps forward into his place, and so the great army marches forward with unbroken ranks.

He who, "in cities pent," sees the sky only through a garret window, or in the narrow intervals between house and house, can form no accurate idea of the magnificence of the firmament. The peasant, the shepherd, or the labourer, spent with his daily work, prefers sleep to astronomical vigils; and even amongst those more favoured sons of fortune, who enjoy sufficient leisure, but few are found who feel a genuine pleasure in the study of the stars. Though they are the poetry of heaven, their music is inaudible to the majority of souls. We content ourselves with an occasional careless glance at their serene loveliness, and then turn again to the pleasures or avocations of commonplace life.

But, come; let us arouse ourselves! Let us quit the city for awhile; let us throw off all thought of its too-engrossing pursuits; let us find time to count the stars. Gentle readers, I ask you to follow me.

Ah, me! how small is the train of followers! How great my delusion in supposing that a complete phalanx of students of the celestial wonders would reply to my invitation!

We have now arrived in the open country; and here, on the summit of this gentle ascent, crowned with a clump of leafless trees, we pause. The sky glitters with a cold, keen light, which is reflected back by the snowy plains. While the eye ranges delightedly over the starry vault, the ear is struck by the distant sound of bells, which, at the midnight hour, ring in the infant year—ring in so many hopes and expected joys, and unexpected sorrows—ring out so many passing pleasures and rudely dissipated visions.

As the chime glides softly over the meadows, and along the resounding vales, and through the leafless woods, repeated by echo after echo, until its music dies away in the distance, like our recollections of the dreams of youth, we murmur to ourselves that solemn song of the poet, which so aptly blends the regrets of the past with the anticipations of the future; we exclaim—

The spectacle is majestic and impressive. Let us seek, in the first place, to ascertain our position in reference to the four points of the compass—the four cardinal points. But how is this to be done? By day it is easy enough. I have only to turn myself towards the sun when it has reached the highest point of its diurnal course, and there, in front of me, lies the south, in my rear the north, the east on my left, and on my right the west.

But is it possible to ascertain one's position during the absence of the "orb of day?"

Both possible and easy, provided the sky be clear and cloudless.

But this condition is as necessary by day as by night. How can we determine in which direction lies the south, if the sun be hidden from our gaze by an uniformly opaque atmosphere, and if objects, lit up by a diffuse light, project no shadow at any time of the day?

Endeavour to group together the stars which more particularly strike your gaze; and be careful, in these groupings, to define every fantastic figure which is suggested by your vivid imagination. Undoubtedly, our earliest ancestors, the "world's gray forefathers," proceeded in this manner, in their anxiety to lay hold of some definite guiding-marks in yonder ocean of sparkling atoms. And to study a science by its history is to follow up its successive development.

The Great and the Little Bear.

Observe yonder very remarkable group of seven stars; nearly all are of the same splendour, and they are so arranged as to figure an antique chariot, provided with a somewhat curved axle pole.

Observe it carefully. And not far from this group you will detect another, by no means so conspicuous, but exactly resembling it in form. This second chariot is turned in an inverse direction, and the stars composing it, with three exceptions, are much less brilliant.

Here, then, are two groups of stars, clearly distinguished by their configuration—two constellations, for such is the scientific name given to all the stellar groups.

It has been the fortune of the first of these two groups to strike the eye of the most indifferent observer from the remotest antiquity; and its likeness to a quadriga early procured it the name of a car or chariot. For those Christians who pleased themselves in studding the sky with Biblical personages, it is David's Chariot. This species of apotheosis was borrowed from the Pagans. They placed in the skies their divinities, their demigods, their heroes, and the principal facts and stories of their mythology. For the Greeks and Romans the "Chariot of David" was the female of the Bear, an ursa, or ???t??. Whence came this transfiguration? Listen to the fanciful old myth.

Callisto was the most beautiful of the daughters of the King Lycaon. Jupiter, who may appropriately be styled the "Don Juan" or "Lovelace" of the heathen Olympus, fell in love with her; and she bore him a son, named Arcas, who gave his name to Arcadia, that land of song and fable, groves and streams, where Lycaon exercised his sovereign sway. Juno, the queen of heaven, and wife of the so-called king of gods and men, transported by her jealous rage, changed Callisto into a she-bear; who, one day, would have been unwittingly slain by Arcas, if Jupiter, opportunely appearing on the scene, had not metamorphosed the hunter into another animal, Ursa Minor, or the Little Bear. According to this myth, the Little Bear will be but a transformation of the former, who was the Great Bear, or, before all and above all, the Bear.

It is somewhat surprising, according to certain writers, that Homer should refer to only one of these constellations:—

But the learned commentators who have censured the poet for making no distinction between Ursa Major and Ursa Minor, probably never looked at the starry vault with an attentive eye; otherwise, like all the world, they might have convinced themselves that the seven stars, septem triones (whence the word "septentrion"), forming the beautiful constellation, which, undoubtedly, long before Homer's time, was known as "The Bear" or "The Celestial Chariot," were all that could be seen. With a single exception, these stars are of the second magnitude—that is to say, they, so far as regards their brilliancy, rank next to the most brilliant stars of the firmament. The least conspicuous star in the group—one of the third magnitude—occupies the base of the pole of the Celestial Chariot, or of the Bear's tail; it is the fourth star counting from the extremity of the tail. On celestial charts, it is particularised by the fourth letter of the Greek alphabet, d (delta).

Observe, in passing, that the first of these charts, wherein the stars of a constellation were indicated by Greek characters, appeared in 1603, at Augsburg, under the title of "Uranometria." Its author, Jean Bayer, an amateur astronomer, who died in 1660, conceived the idea of designating by the first letters of the Greek alphabet—a, , ?, d, and so on—the most noticeable stars. The animals bearing the names of the constellations are drawn in this map with very considerable care; but it requires, let us hasten to add, much imagination and good-will to recognise, in the form of a stellar group, the animal shown in the drawing.

Thus far Ursa Major. The four stars of the quadriga, or chariot, have been employed to form the dorso-lumbar region of the animal; the three others define its tail; and, finally, twenty-four little stars, some of which are hardly visible to the naked eye, compose the head and paws of the celestial "plantigrade."

As for Ursa Minor, it is impossible to distinguish it immediately when you are unaccustomed to surveying or examining the celestial vault. To detect its position, you require to be forewarned of it; to know, in the first place, that there exists in the vicinity of the Bear an exactly similar stellar group. The point of the tail—a in Ursa Minor—alone possesses a splendour comparable to that of the principal stars in Ursa Major. But how construct a figure with one star? The four other stars, two of which mark the anterior part of the animal's body, and two others the tail, properly so called, are only of the third magnitude: they are marked , ?, d, e. Finally, the stars which define the posterior portion, marked ? and ? on Bayer's chart, are only of the fourth magnitude--in other words, are scarcely visible. The eye, to detect them, must be wholly free from any gleam of light.

Many generations passed before they succeeded in discovering what a single individual solved during his brief career. All Homer's contemporaries, and, prior to these, tens of millions of mortals, had contemplated the sky, and yet none of them had detected the difference between Ursa Major and Ursa Minor. The distinction, therefore, is of a comparatively recent date; probably does not date back earlier than the sixth century before the Christian era.

Let us recall ourselves, now, to the question propounded. The first impression produced by the aspect of the sky during a beautiful winter night is, we repeat, that the number of the stars is infinite. This wholly spontaneous thought, which, to some extent, imposes itself on the mind long before the reason attempts any calculation, is, strange to say, both false and true.

But how can a thought be both false and true? Nothing is easier than to explain the seeming contradiction. We shall return to it hereafter, after we have indulged in some indispensable digressions.

Orion.

One of the finest and loftiest flights of Longfellow's imagination is to be found in his poem on the occultation of Orion. He has seldom, if ever, sounded a more vigorous strain. After alluding to that music of the spheres which Pythagoras dreamed of, and which Shakespeare has described in a passage of great beauty, he continues:—

The most ancient observer who wished, with his own eyes, to assure himself whether the number of the stars was infinite, must have quickly perceived that, in spite of an apparent impossibility, it is no difficult task to complete their enumeration. To execute this operation conveniently, however, we must invent a process; and of all processes, the simplest, and that which first occurs to the mind, is to group the stars by configurations which, to a certain degree, are mnemo-technical. Such, in our belief, is the true origin—a point so often and laboriously discussed—of the asterisms or constellations. Their fanciful, mythological, or poetical embellishments, are of later date.

The census or enumeration of the stars, which we suppose to have commenced during our winter nights, must at first have been limited to the most characteristic groups, composed of the most brilliant points. In this scientific labour the first rank would necessarily be occupied by Arctos (or Ursa Major) and Orion. Why? Because these two constellations attract and rivet everybody's gaze.

Orion is situated on the side opposite to the Great Bear. It is the most beautiful constellation in our western sky. You may easily recognise it by three stars, very close together, which are inscribed, as it were, in the centre of a great trapezium of four stars, two of which are of the first magnitude. Beneath the three first stars, called the Three Kings, or Orion's Belt, is visible a small stellar group of the fourth and fifth magnitude, near which, with a good average glass, may be distinguished the largest and most remarkable of the nebulÆ.

Here we find the mythologists—those theologians of the Greco-Roman polytheism—at disagreement. According to an ancient legend, immortalised by Homer—

The giant, in the lower world, is still animated by a burning passion for the chase—

According to later traditions, the giant Orion, son of Tura and Neptune, was endowed by his father with the faculty of walking upon the sea as well as upon earth. He abandoned himself to the fierce joys of the chase in the wooded isle of Crete, to whose shades he had accompanied Diana and Latona. Swollen with pride, he defied to combat all the monsters of the universe, and was slain by a scorpion which the earth had engendered under his feet. But, through the intercession of Diana, a place was given to him in the firmament opposite Scorpio.

Diurnal Movement.

Let us put aside these dreams of the world's youth, and return to the reality.

Nature, transformed by the ancients into a multiple divinity, never fails to overwhelm with surprise the observer who interrogates her with simplicity and without any preconcerted system. And it was thus that he who first undertook to enumerate the stars, by the help of the constellations, made at once the greatest and most unexpected discovery. What, in fact, was not his astonishment on seeing the gradual displacement of objects which, at the first glance, appeared immovable!

To this very natural astonishment soon succeeded, we doubt not, a desire to analyse the phenomenon. The most beautiful constellations of the firmament, Ursa and Orion, will have their points of repery on the star-gemmed sphere. An attentive study, eagerly pursued through a certain lapse of time, would teach him that Orion rises and sets like the sun and the moon, while the Bear, remaining perpetually above the horizon, neither rises nor sets. Stimulated by curiosity, the observer would afterwards assure himself that the whole of the celestial vault revolved upon an axis, while the stars divided into groups; remain fixed, fixed in this sense, that they constantly maintain among themselves the same relations of distance. The idea of a solid sphere, to which the stars were attached like golden nails, then came quite naturally to the human mind. Such, undoubtedly, was the origin of the discovery of diurnal movement; of that general movement which carries all the stars from west to east, to bring them back to the same points in the course of one complete day.

To hear our professors of astronomy invariably repeating, that "the spectator of the starry vault may see, every moment, new stars rising above the horizon,—may see them mount the sky,—halt in their upward march when they have attained a certain elevation,—afterwards re-descend, and pass below the horizon;"—to hear, we say, these words incessantly reproduced, one would think that a cursory glance at the sky would suffice to reveal the general movement, and that what is within the ken of the first comer, should not be called a discovery.

But we see in this another of those illusions which blind contemporaries as to the time-long efforts of their predecessors to discover the very results which long ago became our common patrimony. Unquestionably, if you have eyes, you cannot fail to see the apparent movement of the earth and moon; but from thence to the relation of the whole celestial sphere is a wide interval. How many men are there who possess, on the one hand, sufficient patience to fix their gaze only for a couple of hours on the same point of the starry firmament; and, on the other, sufficient intelligence to estimate the relation of this point to a fixed point of the horizon, and to measure, by the thought, the interval separating these two points? Let each one ask himself.

Determination of the Cardinal Points.

However it may be, the discovery of the rotation of the celestial system must have been rapidly brought to perfection as it was transmitted from one generation to another. It must soon have been recognised that this sphere is inclined in such a manner that one of its poles—the poles of the world, which, in reality, are simply the prolonged extremities of the axis of terrestrial rotation—is always above the horizon, while the other remains below. And this phenomenon would lead to the geometrical conception of an axis of rotation of the celestial sphere. Thus we may explain, with perfect ease, why the Bear and the neighbouring constellations should describe perfect circles, and the other and more distant constellations only arcs of circles, of a greater or lesser diameter; finally, without even looking at the sky, we can understand that some stars there are which show themselves on the horizon, only to disappear immediately, and others which remain completely invisible to the inhabitants of our climates. By a singularly fortunate coincidence, the pole, that geometrical point around which revolve those circumpolar constellations that are continually above our horizon, is occupied by a star "well known to fame," and hence, on the faith of its renown, supposed by many people to be a star of peculiar brilliancy.[5] It is named the Polar Star (a in Ursa Minor), and is between the second and third magnitude.

Now if, with arms extended, we so place ourselves that our back shall be turned to Polaris, we shall have opposite to us the point of the arc occupied by the sun at noon; on our left the east, and on our right the west. It is thus we may easily learn our position in the absence of the orb of day.

The discovery of this simple mode of guidance was, nevertheless, an epoch in history. From thence the mariner grew bold enough to quit the coast, which he had hitherto hugged with timorous prudence, and venture out into the open sea. Thenceforth, the darkness disappeared; new countries were revealed to one another, and nations, which from time immemorial had remained apart, were brought into frequent communication.

It was with eyes fixed upon the Bear, which alone does not bathe itself in the waters of Ocean, that Ulysses set out from Calypso's enchanted island.

According to Homer, who reflects in his immortal work the condition of scientific knowledge among his contemporaries, the ocean was a great broad river, surrounding the earth with circumfluent volume, and in its waves the stars were bathed or extinguished in the evening, to be rekindled in the morning on the opposite side.

By saying that the Bear alone does not bathe in the waters of Ocean[6]—

the poet plainly shows that Ursa Minor, and the other circumpolar constellations, were unknown in his time.

If the knowledge of these constellations was from the beginning so useful and so necessary to navigation, the constellation nearest to the pole could not, at first, have served as a guide to any but a people essentially maritime. And here we find the Phoenicians, or Tyrians, in the foremost rank.

After reminding us that Ursa Major was also called Helice, or "the spiral," as in the famous passage in the "Argonauta" of Apollonius Rhodius,—

and Ursa Minor, Cynosura,—that is, the dog's tail,—Manilius,[7] a Latin poet, who wrote at the beginning of the Christian era, goes on to say:—

"At one of the extremities of the world's axis are two constellations, well known to the hapless mariner: they are his guides when the bait of gain impels him across the ocean. Helice is the larger, and describes the larger circle: it is recognised by its seven stars, which rival one another in splendour; and by this it is that the Greeks steer their barks. The smaller, Cynosura, describes a lesser circle: it is inferior both in size and lustre; but, according to the witness of the Tyrians, is of greater importance. For the Phoenicians no safer guide exists when they seek to approach a coast invisible from the high seas."

The testimony of Manilius is confirmed by that of Aratus and Strabo. The pseudo-Eratosthenes, in his book on the constellations, refers to Ursa Minor under the name of F??????, the "Phoenician." It appears, then, to be established that the Phoenicians were the first to group a constellation of the same general outline as Helice, the Little Bear, or Ursa Minor. But that, as we have already explained, the two constellations do not lie in the same direction, every one may see:

Certain it is that the Phoenicians, as experienced seamen, would guide their course by the constellation lying nearest to the pole. But was this constellation the same which we now-a-days call Ursa Minor? It is quite allowable for us to put such a question, because everybody knows that, owing to the movement of the terrestrial axis around the poles of the ecliptic, the axis of the world (the terrestrial axis prolonged) is displaced to an extent which becomes perfectly appreciable at the end of a certain time.[9] We may calculate, therefore, that the pole, now situated, as we have already said, near the star Polaris (a in Ursa Minor), was formerly at some distance from it. So, at the epoch of the greatest prosperity of the Phoenician people, or about three thousand years ago, the north pole would nearly correspond with a star in Draco, now 24° 52' distant.

[This constellation is shown in fig. 2, between Ursa Major and Ursa Minor; the a in Draco is a star surrounded by a circle, like the Polar Star, a in Ursa Minor.]

That the constellation of Draco was well known to the ancients, we may gather from a passage in the "Phenomena" of Aratus, a work partly translated by Cicero:—

"The Dragon, like the sinuous course of a river, uncoils his long scaly body, and surrounds with undulating folds the two constellations of Ursa Major and Ursa Minor."

Bringing together these different facts for the sake of comparison, we arrive at the conclusion that the Polar Star, by whose scintillating light the early mariners steered their tiny keels, was not the Polaris of to-day—a in Ursa Minor—but a in the constellation of the Dragon.

The Arabs, those navigators of the Waterless Sea (as they poetically designate the desert of Sahara), have bestowed particular appellations on several stars; but they guide themselves rather by their radiance than by their position. Thus, such stars as a Draco, a Cepheus, a Cygnus, which have occupied, and, in the course of centuries, will again occupy the place of Polaris, have received no special denomination; while the stars of Ursa Major, a and (occupying the posterior angles of the chariot), are called Dubke and Merak;[10] ?, d, e, ?, ?, which follow in due succession—PhegÆa, or Phad, Megrez, Alioth, Mizar, and AckaÏr, or Benetnasch. Certain stars in the same constellation, which are barely visible, have also received distinctive names: such is Alcor, a star between the fifth and sixth magnitude, in the tail of Ursa Major, between Mizar and Benetnasch. This star, it is true, had a special use: it served the Arabs as the test of a good eyesight.

A further proof that the Arabs founded their stellar nomenclature almost exclusively upon the lustre and colour of the stars, is obvious in the names which they gave to the stars forming the constellation of Orion. (See Fig. 2.) Thus, a and , two stars of the first magnitude, occupying the right or eastern shoulder, and the left or western foot of the giant-hunter, are called respectively, Betelguese and Rigel; the star ?, named Bellatrix, in the left shoulder, is of the second magnitude, like the stars d, e, ?, which represent Orion's Belt, and bear the names of "the Three Kings" and "St James's Staff." Now the star ? marking the right knee or inferior eastern angle of the brilliant trapezium, is only of the third magnitude; therefore, it has received no special designation.

The colour by which some stars are distinguished could not have failed to be remarked by those observers who first began to enumerate, or take census of, the celestial bodies. Thus Sirius, the most refulgent of the stars of heaven, situated in Canis Major, is of a bluish-white, like Rigel; and Arcturus, situated on the prolongation of the tail of Ursa Major, is reddish-yellow, like Betelguese.

Sirius, or the Dog-star, rose heliacally at the hottest time of the year, and hence the Greeks were accustomed to ascribe all the diseases of the season to its influence. It was—

To sum up: the figurative grouping of the stars, the variety of their luminous magnificence, their position towards Polaris, the determination of that position by the longitudinal circles passing through the axis of the world, and twisted perpendicularly to this axis by the circles parallel to the Equator,—such is the aggregate of the elements which must, at a very early period, have presided over the enumeration of those sparkling points, each of which is the centre of a system.

Finally, are there any stars which the eye cannot perceive? Such a question would never have been propounded to the ancients. And why? Because no reasoning would have drawn from them an admission that it was possible by artificial means to enlarge the range of our eyesight. They would have deemed it madness to pretend to improve and develope what is not of human creation; the visual apparatus, as it is bestowed on us by nature, they supposed to be the most perfect instrument which man could imagine. And, in truth, nothing could fairly be objected to this way of looking at things.

The 48 constellations (21 northern, 12 zodiacal, and 15 austral) indicated by PtolemÆus, contain a total of 1026 stars, whose relative positions had been determined by Hipparchus. To undertake an enumeration of the stars, and to transmit the result to posterity, appeared to Pliny an audacity before which even a god would have recoiled (Hipparchus—ausus, rem etiam Deo improbam, annumerare posteris stellas).[11]

Yet numerous doubts had already risen in the mind of Hipparchus as to the accuracy of the number recognised. In the first place, the ancients undoubtedly knew, as we do, that the visual faculty is not the same in all individuals; that there are some who, in the same celestial space, see more stars than others. Many persons can discern up to stars of the seventh magnitude, while with others the sight fails far within that limit. The ancients must also have known, as we do, that, for the enumeration to be complete, the sky must be observed from all the points of the terrestrial surface on which man is planted. Even in our own days the catalogues of the southern heavens are far from being perfect. Finally, more than two thousand years before the time of Galileo, Democritus had already enunciated the opinion that the Milky Way was a mass of innumerable stars. All these signs should have been accepted as warnings against premature affirmations.

The invention of telescopes suddenly enlarged the question, and it became necessary to establish a line of demarcation between the number of stars visible to the naked eye and the number visible through the agency of the telescope. Argelander, the author of the "Uranometria," has found that the stars visible to the naked eye, over the entire surface of the heavens, range from 5000 to 5800. Otto Struve, employing Herschel's method of computation, has estimated at upwards of twenty millions (20,374,034) the number of stars visible with the Herschel 20-feet telescope.

But, in presence of all the nebulÆ resolvable into stellar masses, and before the development of the artificial range of our sight,—in presence, finally, of that hopeless perspective which the more we discover the more we perceive how much there remains to discover,—are we not forcibly carried back to our point of departure?

Ought not the imagination which, at the first glance, led us to believe the number of stars to be infinite,—ought it not to draw us nearer to the truth?

How should the imagination reveal to us, without difficulty, what the intellect, assisted by the senses, can only discover after ages of assiduous exertion?

These questions, it seems to us, are worthy of our studious consideration.

We subjoin a table of the constellations in both hemispheres, with the number of stars in each, for the convenience of our younger readers.