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she disappeared with the dog in the dining-room.

I did not follow her; I stood by the parlor window, and thought over the last few hours.

How terrible!

A light step in the dining-room, the clattering of plates; "Come, Rube," said Gretchen, gently, "come!"

After a while she came up to my side and took me by the hand.

"Forgive me, Rudolph!" "For what, Gretchen?"

"The dog-Rube, our Rube! I know it has pained you for years, that I-" I stroked her soft hair. "Never mind, Gretchen, all is forgotten at-this moment!"

At that very instant he squeezed himself through the narrow opening of the door, and trotted up to me.

"Good old fellow, how shall we ever thank you!"

He stood before us, wagging his tail, and looked from one to the other as if to say: "Why make so much fuss, you

silly people? I only did my duty as a good dog!"

And thus we sat long and silently at the bedside of the child; Rube lay in my lap as in the old days.

The joyous and blessed Christmas Eve descended over the earth, and spoke to us of love and peace. Our hands were closely locked in true Christian thankfulness. Aye, love and peace over the wide world, love and peace in the narrow world of our house.

Mark you their blessed influence? When have we looked into each other's eyes so lovingly, my Gretchen and I? No shadow, no grudge, between us.

You, too, my little black friend-you, too, share in this peace. In cold and hunger you will never again sit on the threshold, and cast on me the touching, imploring gaze of a dumb, ill-treated brute-never again!

Softly ticks the clock, softly rustle the fir-tree's golden streamers; and softly breathes our darling child. Abide with us ever more, love and peace.

MARS AS A WORLD.

During the early months of last year many astronomers directed their "optictubes" to the ruddy disc of Mars, which was then conspicuously visible in the midnight sky. The planet did not approach the earth so closely as it sometimes does in its periodical visitations, but it was high above the horizon, and therefore well situated for observation. Startling discoveries were scarcely expected, though eager eyes were strained in the effort to distinguish new and true markings on the Martian face. But it is, perhaps, just as well that no very novel characteristics were observed; for the absence of new information enables fuller consideration to be given to

the facts already available. The present thus seems an appropriate time to make a general survey of the planet's features, and to describe some explanations of them which have recently attracted the attention of astronomers.

The first duty of a man of science is to observe accurately and with discrimination; the next, to interpret his contributions to knowledge. It is, however, much easier to develop keenness of perception than it is to find the cause of the phenomena presented. A good telescope, a clear atmosphere, and an acute observer will add more to astronomical knowledge in an hour than can be explained in a lifetime; so facts

accumulate far more rapidly than they can be read. Especially is this the case in celestial matters. For a long time the general features of the planet Mars have been known. A comparatively small telescope shows that more than half the surface is made up of extensive regions of a reddish-yellow tint, while the remainder consists of darker bluegreen patches and two white "caps" around the poles. Arguing from analogy with the earth, the light and dark markings which constitute nine-tenths of the area of Mars are held to represent land and water. But which is land and which is water cannot yet be definitely determined, though the general opinion is that the darker portions of the surface represent Martian oceans and the lighter areas land.

THE POLAR REGIONS.

The nature of the polar caps is known with a high degree of probability. As the summer advances in the northern hemisphere of Mars, the white polar region is seen to decrease slowly until it becomes so small as to be invisible to the largest telescopes. This dwindling has not merely been observed once or twice, but dozens of times. And not only does the north polar cap shrink continuously as the summer sun shines more strongly upon the boreal hemisphere, but a similar, and just as striking a diminution takes place round the south pole of the planet when the summer season is advancing in the southern hemisphere of Mars. Day by day, and month by month, the polar caps have been measured, and their decrease of size has been proved to take place concurrently with the progress of winter to summer on Mars. No characteristic of the planet is known with anything like the same certainty, and none admit of simpler explanation. The polar caps are evidently regions of ice and snow, in every respect similar

to our arctic and antarctic seas. During the winter in either the northern or the southern hemisphere the frozen polar sea extends its limits; but its growth is checked in spring-time, and as the summer comes on, as the sun climbs higher and higher in the Martian sky, the sunbeams gain daily in strength and directness and the ice and snow disappear before them.

Polar expeditions on the earth are attended with no little danger; the polar exploration of Mars can be accomplished without loss of life or risk of frost-bite, and with a greater probability that new knowledge will be acquired. Astronomers are the explorers in this case, and by their telescopes they have been able to find out much more concerning the southern frozen sea of Mars, which, at its nearest, is thirty million miles away, than is known of our own Antarctic regions. In 1894, when the planet was exceptionally well situated for observation, the appearance and changes in the south polar cap were made the subject of investigation by Mr. Percival Lowell, whose volume on "Mars" has given pleasure to many, and will frequently be referred to in the course of this article.

THE MELTING OF THE SNOWS.

Two months before the longest day in the southern hemisphere of Mars the polar cap was seen at Mr. Lowell's observatory as an unbroken waste of white more than two thousand miles across. Hundreds of square miles of this Martian ice and snow disappeared daily, melted by the sun's rays, and, as it melted, a dark band appeared surrounding it on all sides. The obvious conclusion is that this dark blue ring was water produced by the melting of the polar snow, which interpretation is supported by the fact that as the white cap dwindled the band kept pace with it, and persistently bordered the disap

pearing crown. Moreover, it was the color of water, and the light coming from it was of precisely the same character as that reflected from water surfaces on the earth. From these facts, then, astronomers are led to believeand the belief amounts almost to a certainty-that water exists on Mars, both in the solid form as snow and ice and in the liquid condition.

Dr. Nansen found the basin of the Arctic Sea much deeper than had been anticipated; but the rapid and total extinction of the polar cap and sea on Mars points exactly to an opposite condition of things. Apparently only a small thickness of snow covers the polar land in winter, and the water formed when this melts is very shallow. The actual depth of the polar basin cannot, however, be decided, for, so far as telescopic observations go, the same appearances would be presented whether the snow and water were a yard or a mile deep.

The absence of a great oceanic depression at the polar regions of Mars seems to be typical of the whole of the planet. On the earth, if all the land were rolled out flat, so as to make an even surface, the top of the surface would be about two thousand feet above sea-level, while the ocean basin, if similarly smoothed, would be about two miles below sea-level. On Mars, however, the difference of level between the average land surface and sea bottom is probably extremely slight, so that a comparatively small volume of water is able to submerge a large area. The course of events which follow the melting of the polar cap indicate that such is the case. We are at present so well off for water that the melting of polar snow and ice in the summer makes no appreciable difference to the sea-level. But on Mars the unlocking of the frozen seas is of as much importance as the annual inundation of the Nile is to the Fellaheen of Egypt.

THE CANALS.

Mr. Lowell's observations show that the polar sea which has its source in the melted snow plays deus ex machina to all the subsequent seasonal changes on the surface of the planet. The wonderful "canals" or "channels" which were discovered in 1877, but the reality of which was doubted for nearly ten years, and is not yet beyond suspicion in the minds of hypercritical astronomers, seem to be dependent upon the melting of the polar snow for the water to fill them. So soon as the change from snow to water is thoroughly under way the canals begin to show themselves, and the first to become visible are those nearer the polar sea-those, in fact, which would be first reached by the wave of water moving into warmer latitudes on Mars. Eventually the orange-red areas of the planet-the regions regarded as continents-are seen to be traversed by canals, which cross the desert-like ground in every direction, as fine, straight, dark lines starting from bays and running to definite centres like the paths in an ornamental garden run towards the flowerbeds.

What the canals on Mars exactly are it is difficult to say. The narrowest of them cannot be much less than thirty miles wide, and the average width is about fifty miles, and one measures 3,500 miles. It must be borne in mind, however, that though these lines appear perfectly straight, they may not be absolutely so, for the finest telescope in the world could not reveal a deviation of less than fifteen miles to the right or left of the general canal course. The best instruments are thus only coarse analyzers of optical feattures, and astronomers cannot be sure that what is seen by their aid represents the ultimate character of the view. This fact has given a basis to the suggestion that possibly the canals

wind to and fro after the manner of terrestrial rivers, the details being too minute to be separately discerned; but no evidence can be brought forward either for or against this view.

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The network of lines upon the surface of Mars has been seen by many astronomers, and many have attempted to interpret them, most of the explanations being plausible, but none convincing. If we consider the land surface of Mars to be of a softer nature than the crust of the earth-to be, in fact, similar in constitution to our own desert regions, which it closely resembles in color, the flow of water produced by the rapid melting of the polar snows would soon wear a way through it. A narrow canal cut in the dry season would become filled in the wet season and the overflowing water would make a much wider channel for itself. Each annual flood might thus flow into wider limits, and in the course of time a broad canal would appear. This suggestion is put forward because, judging from the tremendous labor involved in the construction of even a small canal earth, it seems impossible that furrows from thirty to a hundred miles wide could be cut along the surface of Mars. But that is because things are considered too much from the terrestrial point of view, the practicability of engineering projects on Mars being estimated in the light of engineering experience on the earth. It may be as easy for Martian engineers to plough a canal thirty miles wide on the surface of the planet as it is to wear away the soft banks of rivers on the earth by playing upon them with jets of water under hydraulic pressure. On the Mississippi enormous portions of the crumbling bank have been scoured out in this way so as to confine the river to a certain channel. The labor involved in the construction of a canal on Mars would probably be little more than that employed in regulating the flow of the

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A very attractive explanation of the appearance of the canals upon Mars as the snow cap dies away has been put forward by Mr. Lowell. He holds that what are regarded as canals are not canals at all, but strips of fertilized land bordering a thread of water too small to be perceptible. It has already been stated that Mars appears to be badly off for water, so that the inhabitants, if there be any, are dependent upon the melting of the polar snows for practically their whole supply. In this case crops could only be cultivated along strips of land bordering the channel through which the water is made to flow. Mr. Lowell suggests that to be able to live at all, the Martians have had to develop an elaborate system of irrigation, and only on these irrigated bands does vegetation flourish, the great regions of reddish-ochre tint being dreary wastes of desert land, from which all organic life has long been driven.

The scarcity of water on Mars is a natural consequence of the planet's great age and small size. Mars is not a fiery youth in the planetary family, but is well advanced in years, and relatively much older than the earth. He is smaller, too, for seven planets of his size would be required to build up one globe as large as the earth. As a consequence, his duration of life, from the time when he was hurled into the blue a nebulous mass until he rolls

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through space as dead as the moon, is less than that of the earth; for the smaller the planet, the quicker must it cool down, and when the internal heat is gone, life, as we know it, becomes impossible. In all probability a planet dries up with advancing years, the water sinking from the surface to the interior, leaving the ocean floors as dry as they now are upon our satellite. Water is also used up by chemical combination with various substances, common instances of this kind being afforded by plaster of Paris and cement. Mars has apparently not yet lost all its water, but the supply seems to be very limited, and the problem of husbanding what is available, and of utilizing it for the purposes of irrigation, must be to the Martians of paramount importance. Even at the present time the water question has to be very seriously considered upon the earth; but, as our globe grows old, it will become the chief material concern of the surviving remnant of humanity, as Mr. Lowell shows it now is on Mars.

OASES IN MARTIAN DESERTS.

A remarkable feature of the canals on Mars (we still designate them by that word, spite the probability that it does not express their real character) is that they proceed to what seems centres in the middle of the continental area. These dark areas, together with the canals that lead to them, are the only markings on the land surface, and Mr. Lowell regards them as great oases. The majority of the spots are from one hundred and twenty to one hundred and fifty miles across, but one of them is more than five hundred miles long and three hundred miles broad. spots, like the canals, become more conspicuous as summer advances, the suggested explanation being that they are areas of verdure, which, under the waxing warmth of the sun's rays, deep

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en in tint and increase in luxuriance. Their evident connection with the system of dark lines seen upon the planet, their regularity of form, their seasonal darkening, and their distribution over continental regions, give support to the view that they are oases in the midst of Martian deserts, and that the canals have been constructed for the express purpose of irrigating them. Upon these meadows and along the strips of land converging to them, apparently live whatever forms of life Mars is capable of sustaining.

DOUBLE CANALS.

These interpretations of markings on Mars are very attractive, and they explain satisfactorily the phenomena seen; but one remarkable characteristic -the doubling of the canals-remains unintelligible. There is no doubt whatever that under good observing conditions, and at certain seasons of the Martian year, canals which had previously been seen as single dark lines appear double. Side by side, like the twin lines of a railroad, the two canals run together for hundreds and, sometimes, for thousands of miles, the distance between them being from about fifty to two hundred miles. All the canals are not seen double at the optical delusion (if might be suspected. become duplicated at but seasonable changes appear to govern the twining of all of them. Following up the idea that the so-called canals are strips of cultivated land, Mr. Lowell suggests that the doubling is caused by changes in the character of the vegetation. It is not difficult to conceive of crops ripening first near the narrow streak of water which fertilizes them, and afterwards on the outer edges of the cultivated belt; and, if vegetation on Mars is light-colored at one period of its growth, and dark-col

same time, or an nothing worse) Different canals different times,

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