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THE MILKY WAY.

HE nebulous band or zone of light known as the Milky Way or Galaxy is familiar to everyone, and on a clear moonless pois night forms a conspicuous feature of the nocturnal heavens. It has attracted the attention of astronomers and philosophers from the earliest ages of antiquity, and various theories have been advanced to account for its appearance. One of the ancient writers— Anopides-considered it to be the original pathway of the sun. Plutarch saw in it the marks of Phaeton's accident. Anaxagoras thought it was the shadow of the earth; and Aristotle that it was due to atmospheric vapours! Other equally absurd theories were entertained by the ancients, and Ovid says-in his "Metamorphoses" -"When the sky is very clear a path of very radiant white colour may be seen in the empyrean. It is called the Milky Way, and along it the immortals repair to the august dwelling-place of the Lord of Thunder"; a fable which is also referred to by Plato. The true theory, namely, that its light originates from myriads of small stars, was, however, advanced by Democritus, Manilius, and Pythagoras, and on the invention of the telescope this hypothesis was fully confirmed.

The representations of the Milky Way shown in popular atlases merely give a general idea of its appearance, and show little or no detail of the brightness and faintness of the various parts-features which are very obvious when carefully observed. A mere passing glance might lead a casual observer to suppose that the Galaxy stretched as a band of nearly uniform brightness across the face of the sky, but good eyesight, careful attention, and a clear sky will soon disclose numerous details previously unsuspected streams nd rays of varying brightness intersected by rifts of darkness, and terspersed with spots and channels of comparatively starless spaces. Heis gives, in his excellent atlas, an elaborate delineation of the ky Way as seen in northern latitudes. He divides the varying htness of the different parts into five magnitudes, the first magide being assigned to the luminous portions of the Galaxy in the

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of the little Trianon. The acacias and chest puts were still in flower, cuckoos were singing lustily, and, for a wonder, the solitude was unbroken. Almost within sight was the grotto where Marie Antoinette was sitting when they came to tell her the mob from Paris was on its way to Versailles-the day on which she bade farewell to this beloved spot for ever. . . . What a via dolorosa from here to that dark, damp cell in the Conciergerie! Her Temple of Love ill stands, but the white pillars are weather-stained and green with then, the stream that meandered past is filled up with grass and weeds, e tiny bridges are broken, the waterfalls have ceased to flow. The ty little rustic cottages of the Hameau, in the planning and bui of which she took so much innocent delight, remain, outwa unimpaired, but they are closed and desolate. One peeps through a broken pane to catch glimpses of the small staircases and passages, up and down which red-heeled shoes and dainty feet once pattered lightly. An air of damp and mildew has crept over them. But better so; better neglect than they should be kept up, as in the Empire days, for show. Marie Antoinette's Arcadia makes thus, in its weeds and desolation, a far more pathetic appeal to memory.

Oh, sweetest and most melancholy of spots! If ever ghosts walk this mortal earth they must surely haunt the Hameau in the warm hush of moonlit summer nights. Sitting there in the cheerful morning sunshine, with the banksia roses blooming yellow about the wooden balcony of the Queen's cottage overhead, I saw no ghosts. But my mind, straying back to that long gone Past, strove to evoke its brighter memories, strove to call up across the century's space that intervened the faces of dear dead men and women—the faces of Marie Antoinette and Axel de Fersen.

THE MILKY WAY.

THE

HE nebulous band or zone of light known as the Milky Way or Galaxy is familiar to everyone, and on a clear moonless night forms a conspicuous feature of the nocturnal heavens. It has attracted the attention of astronomers and philosophers from the earliest ages of antiquity, and various theories have been advanced to account for its appearance. One of the ancient writersEnopides-considered it to be the original pathway of the sun. Plutarch saw in it the marks of Phaeton's accident. Anaxagoras thought it was the shadow of the earth; and Aristotle that it was due to atmospheric vapours! Other equally absurd theories were entertained by the ancients, and Ovid says-in his "Metamorphoses" -"When the sky is very clear a path of very radiant white colour may be seen in the empyrean. It is called the Milky Way, and along it the immortals repair to the august dwelling-place of the Lord of Thunder"; a fable which is also referred to by Plato. The true theory, namely, that its light originates from myriads of small stars, was, however, advanced by Democritus, Manilius, and Pythagoras, and on the invention of the telescope this hypothesis was fully confirmed.

The representations of the Milky Way shown in popular atlases erely give a general idea of its appearance, and show little or no tail of the brightness and faintness of the various parts-features ich are very obvious when carefully observed. A mere passing nce might lead a casual observer to suppose that the Galaxy etched as a band of nearly uniform brightness across the face of sky, but good eyesight, careful attention, and a clear sky will n disclose numerous details previously unsuspected: streams rays of varying brightness intersected by rifts cf darkness, and rspersed with spots and channels of comparatively starless spaces. Heis gives, in his excellent atlas, an elaborate delineation of the Way as seen in northern latitudes. He divides the varying tness of the different parts into five magnitudes, the first magJe being assigned to the luminous portions of the Galaxy in the

constellation of the Swan and in "Sobieski's Shield," and the fourth and fifth magnitudes to the very faint nebulous light which he shows filling in the vacuities (drawn on other star maps), and bordering the Milky Way on both sides throughout nearly the whole of its course. This method of division into magnitudes is of course, to a great extent, an arbitrary one, and the lines of demarcation between the assumed magnitudes are not so sharply defined in the sky as shown in Heis' maps. There is also reason to think that Heis did not pay so much attention to the Milky Way as he did to his star magnitudes. Still, his drawing serves to give a fair representation of the general effect visible to a keen-sighted and careful observer, as Heis undoubtedly

was.

Heis' drawing of the Milky Way extends to about thirty degrees of South declination-about the limit visible in these latitudes. Below that limit we have an excellent drawing of the southern portion of the Galaxy by Sir John Herschel (which will be found in his valuable "Cape Observations "), and a very elaborate representation made at Cordova in the Argentine Republic, given in the charts of Dr. Gould's "Uranometria Argentina."

Another carefully drawn representation of the Milky Way will be found in Houzeau's atlas. This, as the independent work of one observer for both hemispheres, has a certain value, although his drawing is somewhat diagrammatic and deficient in detail. The method of delineation adopted by Houzeau was to trace the lines of equal brightness (or "isophotes" as he terms them) of the various portions of the Milky Way. These somewhat resemble, he says, the "contour lines" on terrestrial maps, and are filled in with a blue tint, the washes of colour being placed one over the other, so that "Plus il y a de courbes, plus l'espace renfermé dans la dernière est brillant." As in Heis's drawing, Houzeau shows five gradations of brightness, and these he determined by comparing the brilliancy of different portions of the Milky Way with neighbouring stars of the magnitudes 6-7, 6, 5–6, 5, and 4–5. In making this comparison he was guided by the appearance or disappearance of the luminous patches of Milky Way light in the twilight or moonlight simultaneously with the stars of comparison. It seems doubtful, however, whether this method is susceptible of any great accuracy, the comparison of a bright point, like a star, with a nebulosity extending over a considerable area of the sky, being evidently a matter of much difficulty and considerable uncertainty. The visibility of the star and the adjoining nebulosity might not, in all cases, be equally affected by varying atmospheric conditions, and the gradations of

light in the different portions of the Galaxy are so gradual, numerous, and complicated that most of the smaller details would unavoidably be lost in such a rapid survey of the heavens as that undertaken by Houzeau, who estimated the magnitudes of all the stars visible to the naked eye-in addition to his drawing of the Milky Way-in the short period of thirteen months. The drawing being, however, the work of a single observer, and so accomplished an astronomer as the late M. Houzeau, and moreover executed from observations made in a favourably situated station like Jamaica, possesses a value to which it might not otherwise be entitled.

The extension of the Milky Way zone, as drawn by Houzeau, is considerably less than that shown by Heis, much of the faint bounding nebulosity drawn by the latter astronomer being wanting in Houzeau's delineation. According to a computation made by Herr J. Plassmann the area covered by Milky Way light in Houzeau's drawing is about one-tenth of the whole star sphere, a considerably smaller area than the extension shown by Gould and Heis.

The best representation we now have of the northern portion of the Galaxy is a drawing recently completed by Dr. Otto Boeddicker. This beautiful picture of the Milky Way, as seen with the naked eye in these latitudes, is exquisitely drawn, and evidently the work of an admirable observer and accomplished draftsman. At first sight it might perhaps seem open to one objection, and that is the almost evanescent faintness of some of the less luminous portions of the Galactic zone. But this could not have been avoided without giving to the brighter parts a greater prominence than a faithful representation of Nature would reasonably permit. It must be remembered that even the brightest portions of the Milky Way are merely brilliant by contrast with the dark background of the heavens, and that even faint moonlight or slight haze is sufficient to totally obliterate its more delicate details. Even partial success in the delineation of so excessively difficult an object as the Galaxy would be in the highest degree creditable, and it will, I think, be admitted by those who have seen the original drawings that Dr. Boeddicker's success has been even greater than we might have expected from so excellent an astronomer. An eloquent writer in the Saturday Review says his maps "are in many respects a completely new disclosure. Features barely suspected before come out in them as evident and persistent; every previous representation appears by comparison structureless. There is something of organic regularity in the manner of divergence of innumerable branches from a knotted and gnarled trunk; nor can the protrusion of cloudy feelers towards outlying nebula and clusters