FOOTNOTES

Sunrise on Clavius, Tycho, Plato, etc.Sunrise on Clavius, Tycho, Plato, etc.

Clavius (11) is one of the most impressive of all the lunar formations. There probably does not exist anywhere upon the earth so wild a scene upon a corresponding scale of grandeur. Of course, its details are far beyond the reach of the instrument we are supposed to be using, and yet, even with a field-glass, or a powerful opera-glass, some of its main features are visible. It is represented in our picture of the half-moon, being the lowest and largest of the ring-like forms seen at the inner edge of the illuminated half of the disk; the rays of the rising sun touching the summits of some of the peaksin its interior have brought them into sight as a point of light, and at the same time, reaching across the gulf within, have lighted up the higher slopes of the great mountain-wall on the farther or eastern side of the crater-valley, making it resemble a semicircle of light projecting into the blackness of the still unilluminated plains around it. I should advise every reader to take advantage of any opportunity that may be presented to him to see Clavius with a powerful telescope when the sun is either rising or setting upon it. Neison has given a spirited description of the scene, as follows:

The sunrise on Clavius commences with the illumination of a few peaks on the western wall, but soon rapidly extends along the whole wall of Clavius, which then presents the appearance of a great double bay of the dark night-side of the moon penetrating so deep into the illuminated portion as to perceptibly blunt the southern horn to the naked eye. Within the dark bay some small, bright points soon appear—the summits of the great ring-plains within—followed shortly by similar light-points near the center, due to peaks on the walls of the smaller ring-plains, these light-islands gradually widening and forming delicate rings of light in the dark mass of shadow still enveloping the floor of Clavius. Far in the east then dimly appear a few scarcely perceptible points, rapidly widening into a thin bright line, the crest of the great southeastern wall of Clavius, the end being still lost far within the night-side of the moon. By the period the extreme summit of the lofty wall of Clavius on the east becomes distinct, fine streaks of light begin to extend across the dark mass of shadow on the interior of Clavius, from the light breaking through some of the passes on the west wall and illuminating the interior; and these streaks widen near the center and form illuminated spots on the floor, when both east and west it still lies deeply immersed in shadow,strongly contrasting with the now brightly illuminated crest of the lofty east wall and the great circular broad rings of light formed by the small ring-plains within Clavius. The illumination of the interior of Clavius now proceeds rapidly, and forms a magnificent spectacle: the great, brightly illuminated ring-plains on the interior, with their floors still totally immersed in shadow; the immense steep line of cliffs on the east and southeast are now brilliantly illuminated, though the entire surface at their base is still immersed in the shades of night; and the great peaks on the west towering above the floor are thrown strongly into relief against the dark shadow beyond them.

Newton (12) is the deepest of the great crateriform chasms on the moon. Some of the peaks on its walls rise twenty-four thousand feet above the interior gulf. Its shadow, and those of its gigantic neighbors—for the moon is here crowded with colossal walls, peaks, and craters—may be seen breaking the line of sunlight below Clavius, in our illustration. I have just spoken of these great lunar formations as chasms. The word describes very well the appearance which some of them present when the line separating day and night on the moon falls across them, but the reader should not be led by it into an erroneous idea of their real character. Such formations as Newton, which is one hundred and forty miles long by seventy broad, may more accurately be described as vast depressed plains, generally containing peaks and craters, which are surrounded by a ring of steep mountains, or mountain-walls, that rise by successive ridges and terraces to a stupendous height.

The double chain of great crater-plains reaching half across the center of the moon contains some of the grandest of these strange configurations of conjoined mountain, plain, and crater. The names of the principal ones can be learned from the map, and the reader will find it very interesting to watch them coming into sight about first quarter, and passing out of sight about third quarter. At such times, with a field-glass, some of them look like enormous round holes in the inner edge of the illuminated half of the moon. Theophilus(23), Cyrillus (24), and Catharina (25), are three of the finest walled plains on the moon—Theophilus, in particular, being a splendid specimen of such formations. This chain of craters may be seen rapidly coming into sunlight at the edge of the Sea of Nectar, in our picture of "Sunrise on the Sea of Serenity," etc. The Altai Mountains (26) are a line of lofty cliffs, two hundred and eighty miles in length, surmounting a high table-land.

The Caucasus Mountains (38) are a mass of highlands and peaks, which introduce us to a series of formations resembling those of the mountainous regions of the earth. The highest peak in this range is about nineteen thousand feet. Between the Caucasus and the Apennines (44) lies a level pass, or strait, connecting the Sea of Serenity with the Sea of Showers. The Apennines are the greatest of the lunar mountain-chains, extending some four hundred and sixty miles in length, and containing one peak twenty-one thousand feet high, and many varying from twelve thousand to nearly twenty thousand. It will thus be seen that the Apennines of the earth sink into insignificance in comparison with their gigantic namesakes on the moon. As this range runs at a considerable angle to the line of sunrise, its high peaks are seen tipped with sunlight for a long distance beyond the generally illuminated edge about the time of first quarter. Even with the naked eye the sun-touched summits of the lunar Apennines may at that time be detected as a tongue of light projecting into the dark side of the moon. The Alps (41) are another mountain-mass of great elevation, whose highest peak is a good match for the Mont Blanc of the earth, after which it has been named.

Plato (42) is a very celebrated dark and level plain, surrounded by a mountain-ring, and presenting in its interior many puzzling and apparently changeable phenomena which have given rise to much speculation, but which, of course, lie far beyond the reach of opera-glasses. Plato isseen in the picture of "Sunrise on Clavius," etc., on page 133, being the second ring from the top.

If Ariosto had had a telescope, we might have suspected that it was this curious plain that he had in mind when he described that strange valley in the moon, in which was to be found everything that was lost from the earth, including lost wits; and where the redoubtable knight Astolpho, having been sent in search of the missing wit of the great Orlando, was astonished to find what he sought carefully preserved in a vial along with other similar vials belonging to many supposedly wise people of the earth, whom nobody suspected of keeping a good part of their sapience in the moon.

Copernicus (46) is the last of the lunar formations that we shall describe. It bears a general resemblance to Tycho, and is slightly greater in diameter; it is, however, not quite so deep. It has a cluster of peaks in the center, whose tops may be detected with a field-glass, as a speck of light when the rays of the morning sun, slanting across the valley, illuminate them while their environs are yet buried in night. Copernicus is the center of a system of light-streaks somewhat resembling those of Tycho, but very much shorter.

We must not dismiss the moon without a few words as to its probable condition. It was but natural, after men had seen the surface of the moon diversified with hills and valleys like another earth, that the opinion should find ready acceptance that beings not unlike ourselves might dwell upon it. Nothing could possibly have been more interesting than the realization of such a fancy by the actual discovery of the lunar inhabitants, or at least of unmistakable evidence of their existence. The moon is so near to the earth, as astronomical distances go, and the earth and the moon are so intimately connected in the companionship of their yearly journey around the sun, and their greater journey together with the sun and all his family, through the realms of space, thatwe should have looked upon the lunar inhabitants, if any had existed, as our neighbors over the way—dwelling, to be sure, upon a somewhat more restricted domain than ours, vassals of the earth in one sense, yet upon the whole very respectable and interesting people, with whom one would be glad to have a closer acquaintance. But, alas! as the powers of the telescope increased, the vision of a moon crowded with life faded, until at last the cold fact struck home that the moon is, in all probability, a frozen and dried-up globe, a mere planetary skeleton, which could no more support life than the Humboldt glacier could grow roses. And yet this opinion may go too far. There is reason for thinking that the moon is not absolutely airless, and, while it has no visible bodies of water, its soil may, after all, not be entirely arid and desiccated. There are observations which hint at visible changes in certain spots that could possibly be caused by vegetation, and there are other observations which suggest the display of electric luminosity in a rarefied atmosphere covering the moon. To declare that no possible form of life can exist under the conditions prevailing upon the lunar surface would be saying too much, for human intelligence can not set bounds to creative power. Yet, within the limits of life, such as we know them, it is probably safe to assert that the moon is a dead and deserted world. In other words, if a race of beings resembling ourselves, or resembling any of our contemporaries in terrestrial life, ever existed upon the moon, they must long since have perished. That such beings may have existed, is possible, particularly if it be true, as generally believed, that the moon once had a comparatively dense atmosphere and water upon its surface, which have now, in the process of cooling of the lunar globe, been withdrawn into its interior. It certainly does not detract from the interest with which we study the rugged and beautiful scenery of the moon to reflect that if we could visit those ancient sea-bottoms, or explore those glittering mountains, we might, perchance, find there some remains or mementos of a race that flourished, and perhaps was all gathered again to its fathers, before man appeared upon the earth.

That slight physical changes, such as the downfall of mountain-walls or crater-cones, still occasionally occur upon the moon, is an opinion entertained by some selenographers, and apparently justified by observation. The enormous changes of temperature, from burning heat under a cloudless sun to the freezing cold of space at night with no atmospheric blanket to retain heat (which has generally been assumed to be the condition of things on the moon), would naturally exert a disintegrating effect upon the lunar rocks. But the question is now in dispute whether the surface of the moon ever rises above the freezing-point of water, even under a midday sun.

Mankind has always been a little piqued by the impossibility of seeing the other side of the moon, and all sorts of odd fancies have been indulged in regard to it. Among the most curious is the ancient belief that the souls of the good who die on earth are transported to that side of the moon which is turned away from the earth; while the souls of the wicked sojourn on this side, in full view of the scene of their evil deeds. The visible side of the moon—with its tremendous craters, its yawning chasms, its frightful contrasts of burning sunshine and Cimmerian darkness, its airless and arid plains and dried-up sea-bottoms exposed to the pitiless cold of open space, and heated, if heated at all, by scorching sunbeams as fierce as naked flame—would certainly appear to be in a proper condition to serve as a purgatory. But we have no reason to think that the other side is any better off in these respects. In fact, the glimpses that we get of it around the corners, so to speak, indicate that the whole round globe of the moon is as ragged, barren, and terrible as that portion of it which is turned to our view.

The Planets.—In attempting to view the planets with anopera-glass, too much must not be expected; and yet interesting views can sometimes be obtained. The features of their surfaces, of course, can not be detected even with a powerful field-glass, but the difference between the appearance of a large planet and that of the stars will at once strike the observer. Mercury, which, on account of its nearness to the sun and its rapid changes of place, comparatively few persons ever see, can perhaps hardly be called an interesting object for an opera-glass, and yet the beauty of the planet is greatly increased when viewed with such aid. Mercury is brilliant enough to be readily distinguishable, even while the twilight is still pretty bright; and I have had most charming views of the shy planet, glittering like a globule of shining metal through the fading curtain of a winter sunset.

Venus is, under favorable circumstances, a very interesting planet for opera-glass observations. The crescent phase can be seen with a powerful glass near inferior conjunction, and, even when the form of the planet can not be discerned, its exceeding brilliancy makes it an attractive object. The flood of light which Venus pours forth, and which is so dazzling that it baffles the best telescopes, to a greater or less extent, in any effort to descry the features of that resplendent disk, is evidently reflected from a cloud-burdened atmosphere. While these clouds render the planet surprisingly lustrous to our eyes, they must, of course, keep the globe beneath them most of the time in shadow. It is a source of keen regret that the surface of Venus can not be seen as clearly as that of Mars, for,a priori, there is rather more reason to regard Venus as possibly an inhabited world than any other of the Earth's sister planets, not excepting Mars. Still, even if we could plainly make out the presence of oceans and continents on Venus, that fact would hardly be any better indication of the possibility of life there than is furnished by the phenomena of its atmosphere. It is an interesting reflection that in admiring the brilliancy of thissplendid planet the light that produces so striking an effect upon our eyes has but a few minutes before traversed the atmosphere of a distant world, which, like our own air, may furnish the breath of life to millions of intelligent creatures, and vibrate with the music of tongues speaking languages as expressive as those of the earth.

Mars, being both more distant and smaller than Venus, does not present so splendid a scene, and yet when it is at or near opposition it is a superb object even for an opera-glass, its deep reddish-yellow color presenting a fine contrast to that of most of the stars. It can often be seen in conjunction with, or near to, the moon and stars, and the beauty of these phenomena is in some cases greatly enhanced by the use of a glass. To find Mars (and the same remark applies to the other planets), take its right ascension and declination for the required date from the Nautical Almanac, and then mark its place upon a planisphere or any good star-map. This planet is at the present time (1888) slowly drawing nearer to the earth at each opposition, and in 1892 it will be closer to us than at any time since 1877, when its two minute satellites were discovered. It will consequently grow brighter every year until then. How splendidly it shines when at its nearest approach to the earth may be inferred from the fact that in 1719 it was so brilliant as actually to cause a panic. This was doubtless owing to its peculiar redness. I well remember the almost startling appearance which the planet presented in the autumn of 1877. Mars is especially interesting because of the apparently growing belief that it may be an inhabited world, and because of certain curious markings on its surface that can only be seen under favorable conditions. The recent completion of the great Lick telescope and other large glasses, and the approach of the planet to a favorable opposition, give reason to hope that within the next few years a great deal of light will be cast upon some of the enigmatical features of Mars's surface.

Jupiter and his Moons.Jupiter and his Moons. (Seen with a Field-glass; seven diameters.)

Jupiter, although much more distant than Mars, is ordinarily a far more conspicuous phenomenon in the sky on account of his vast bulk. His interest to observers with an opera-glass depends mainly upon his four moons, which, as they circle about him, present a miniature of the solar system. With a strong opera-glass one or two of Jupiter's little family of moons may occasionally be caught sight of as excessively minute dots of light half-hidden in the glare of the planet. If you succeed under favorable circumstances in seeing one of these moons with your glass, you will be all the more astonished to learn that there are several apparently well-authenticated instances of one of the moons of Jupiter having been seen with the naked eye.

With a field-glass, however, you will have no difficulty in seeing all of the moons when they are properly situated. If you miss one or more of them, you may know that it is either between you and the planet, or behind the planet, or buried in the planet's shadow, or else so close to the planet as to be concealed by its radiance.

It will be best for the observer to take out of the Nautical Almanac the "configurations of Jupiter's satellites" for the evenings on which he intends to make his observations, recollecting that the position of the whole system, as there given, is reversed, or presented as seen with an astronomical telescope, which inverts objects looked at, as an opera-glass does not. In order to bring the satellites into the positions in which he will see them, our observer has only to turn the page in the Nautical Almanac showing their configurations upside down.

Of course, since the motions of the satellites, particularly of the inner ones, are very rapid, their positions are continually changing, and their configurations are different every night. If the observer has any doubt about his identification of them, or thinks they may be little stars, he has only to carefully note their position and then look at them again the next evening. He may even notice their motion in the course of a single evening, if he begins early and follows them for three or four hours. It is impossible to describe the peculiar attractions of the scene presented by the great planet and his four little moons on a serene evening to an observer armed with a powerful glass. Probably much of the impressiveness of the spectacle is owing to the knowledge that those little points of light, shining now in a row and now in a cluster, are actually, at every instant, under the government of their giant neighbor and master, and that as we look upon them, obediently making their circuits about him, never venturing beyond a certain distance away, we behold a type of that gravitational mastery to which our own little planet is subject as it revolves around its still greater ruler, the sun, to whose control even Jupiter in his turn must submit.

The beautiful planet Saturn requires for the observation of its rings magnifying powers far beyond those of the instruments with which our readers are supposed to be armed. It would be well, however, for the observer to trace its slow motion among the stars with the aid of the Nautical Almanac, and he should be able with a good field-glass to see, under favorable circumstances, the largest of its eight moons, Titan. This is equal in brilliancy to an 8.5 magnitude star. Its position with respect to Saturn on any given date can be learned from the Ephemeris.

It may appear somewhat presumptuous to place Uranus, a planet which it required the telescope and the eye of a Herschel to discover, in a list of objects for the opera-glass. But it must not be forgotten that Uranus was seen certainly several, and probably many, times before Herschel's discovery, being simply mistaken, on account of the slowness of its motion, for a fixed star. When near opposition, Uranus looks as bright as a sixth-magnitude star, and can be easily detected with the naked eye when its position is known. With an opera-glass (and still more readily with a field-glass) this distant planet can be watched as it moves deliberately onward in its gigantic orbit. Its passage by neighboring stars is an exceedingly interesting phenomenon, and it is in this way that you may recognize the planet.

On the evening of May 29, 1888, I knew, from the co-ordinates given in the Nautical Almanac, that Uranus was to be found a short distance east of Mars, which was then only a few degrees from the well-known star Gamma Virginis. Accordingly, I turned my opera-glass upon Mars, and at once saw a star in the expected position, which I knew was Uranus. But there were other small stars in the field, and, supposing I had not been certain which was Uranus, how could I have recognized it? The answer is plain: simply by watching for a night or two to see which star moved. That star would, of course, be Uranus. The accompanying cuts will show the motions of Mars and Uranus with respect to neighboring stars at that time, and will serve as an example of the method ofdistinguishing a planet from the fixed stars by its change of place. In the first cut we have the two planets and three neighboring stars as they appeared on May 29th. These stars were best seen with a field-glass, although an opera-glass readily showed them.

Mars and Uranus, May 29, 1888.Mars and Uranus, May 29, 1888.

Mars and Uranus, June 1, 1888.Mars and Uranus, June 1, 1888.

Mars and Uranus, June 6, 1888.Mars and Uranus, June 6, 1888.

On June 1st the relative positions of the planets and stars were as shown in the second cut. A glance suffices to show that not only Mars but Uranus also has shifted its position with respect to the three immovable stars. This change of place alone would have sufficed to indicate the identity of Uranus. To make sure, the inexperienced observer had only to continue his observations a few nights longer.

On June 6th Mars and Uranus were in conjunction, and their position, as well as that of the same set of three stars, is shown in the third cut. It will be seen that while Mars had changed its place very much more than Uranus, yet that the latter planet had now moved so far from its original position on May 29th, that there could be no possibility that the merest tyro in star-gazing would fail to notice the change. Whenever the observer sees an object which he suspects to be a planet, he can satisfy himself of its identity by making a series of little sketches like the above, showing the position of the suspected object on successive evenings, with respect to neighboring stars. The same plan suffices to identify the larger planets, in the case of which no glass is necessary. The observer can simply make a careful estimate by the naked eye of the supposed planet's distance and bearing from large stars near it, and compare them with similar observations made on subsequent evenings.

The Sun.—That spots upon the sun may be seen with no greater optical aid than that of an opera-glass is perhaps well known to many of my readers, for during the past ten years public attention has been drawn to sun-spots in an especial manner, on account of their supposed connection with meteorology, and in that time there have been many spots upon the solar disk which could not only be seen with an opera-glass, but even with the unassisted eye. At present (1888) we are near a minimum period of sun-spots, and the number to be seen even with a telescope is comparatively very small, yet only a few days before this page was written there was a spot on the sun large enough to be conspicuous with the aid of a field-glass. During the time of a spot-maximum the sun is occasionally a wonderful object, no matter how small the power of the instrument used in viewing it may be. Strings of spots of every variety of shape sometimes extend completely across the disk. Our illustration shows the appearance of the sun, as drawn by the author on the 1st of September, 1883. Every one of the spots and spot-groups there represented could be seen with a good field-glass, and nearly all of them with an opera-glass.

The Sun, September 1, 1883.The Sun, September 1, 1883.

As in all such cases, our interest in the phenomena increases in proportion to our understanding of their significance and their true scale of magnitude. In glancing from side to side of the sun's disk, the eye ranges over a distance of more than 860,000 miles—not a mere ideal distance, or an expanse of empty space, but a distance filled by an actual and, so to speak, tangible body, whose diameter is of that stupendous magnitude. One sees at a glance, then, the enormous scale on which these spots are formed. The earth placed beside them would be but a speck, and yet they are mere pits in the surface of the sun, filled perhaps with partially cooled metallic vapors, which have been cast up from the interior, and are settling back again. It is worth anybody's while to get a glimpse at a sun-spot if he can, for, although he may see it merely as a black dot on the shining disk, yet it represents the play of physical forces whose might and power are there exercised on a scale really beyond human comprehension. The imagination of Milton or Dante would have beheld the mouth of hell yawning in a sun-spot.

In order to view the sun it is, of course, necessary to contrive some protection for the eyes. This may be constructed by taking two strips of glass four or five inches long and an inch wide, and smoking one of them until you can without discomfort look at the sun through it. Then place the two strips together, with the smoked surface inside—taking care to separate them slightly by pieces of cardboard placed between the ends—and fasten the edges together with strips of paper gummed on. Then, by means of a rubber band, fasten the dark glass thus prepared over the eye-end of your opera-glass in such a way that both of the lenses are completely covered by it. It will require a little practice to enable you to get the sun into the field of view and keep it there, and for this purpose you should assume a posture—sitting, if possible—which will enable you to hold the glass very steady. Then point the glass nearly in the direction of the sun, and move it slowly about until the disk comes insight. It is best to carefully focus your instrument on some distant object before trying to look at the sun with it.

As there is some danger of the shade-glass being cracked by the heat, especially if the object-glasses of the instrument are pretty large, it would be well to get the strips of glass for the shade large enough to cover the object-end of the instrument instead of the eye-end. At a little expense an optician will furnish you with strips of glass of complementary tints, which, when fastened together, give a very pleasing view of the sun without discoloring the disk. Dark red with dark blue or green answer very well; but the color must be very deep. The same arrangement, of course, will serve for viewing an eclipse of the sun.

A word, finally, about the messenger which brings to us all the knowledge we possess of the contents and marvels of space—light. Without the all-pervading luminiferous ether, narrow indeed would be our acquaintance with the physical creation. This is a sympathetic bond by which we may conceive that intelligent creatures throughout the universe are united. Light tells us of the existence of suns and systems so remote that the mind shrinks from the attempt to conceive their distance; and light bears back again to them a similar message in the feeble glimmering of our own sun. And can any one believe that there are no eyes out yonder to receive, and no intelligence to interpret that message?

Sir Humphry Davy has beautifully expressed a similar thought in one of his philosophical romances:

In Jupiter you would see creatures similar to those in Saturn, but with different powers of locomotion; in Mars and Venus you would find races of created forms more analogous to those belonging to the Earth; but in every part of the planetary system you would find one character peculiar to all intelligent natures, a sense of receiving impressions from light by various organs of vision, and toward this result you can not but perceive that all the arrangements and motions of the planetary bodies, their satellites and atmospheres, are subservient. The spiritual natures, therefore, thatpass from system to system in progression toward power and knowledge preserve at least this one invariable character, and their intellectual life may be said to depend more or less upon the influence of light.[G]

Light is a result, and an expression, of the energy of cosmical life. The universe lives while light exists. But when the throbbing energies of all the suns are exhausted, and space is filled with universal gloom, the light of intelligence must vanish too.

One can not read the wonderful messages of light—one can not study the sun, the moon, and the stars in any manner—without perceiving that the physical universe is enormously greater than he had thought, and that the creation, of which the Earth is an infinitesimal part, is almost infinitely more magnificent in actual magnitude than the imaginary domain which men of old times pictured as the dwelling-place of the all-controlling gods; without feeling that he has risen to a higher plane, and that his intellectual life has taken a nobler aim and a broader scope.

FOOTNOTES[A]Let the reader remember that the distance between the two stars in the brim of the bowl of the Dipper is about ten degrees, and he will have a measuring-stick that he can apply in estimating other distances in the heavens.[B]A similar calculation of the internal appearances of the Hercules cluster, which I made, was published in 1887 in the "New York Sun."[C]The Henry Brothers have continued the photographic work described above, and their later achievements are even more interesting and wonderful. They have found that there are many nebulous masses involved in the group of the Pleiades, and have photographed them. One of the most amazing phenomena in their great photograph of the Pleiades is a long wisp or streak of nebulous matter, along which eight or nine stars are strung in a manner which irresistibly suggests an intimate connection between the stars and the nebula. This recalls the recent (August, 1888) discovery made by Prof. Holden, with the great Lick telescope, concerning the structure of the celebrated ring nebula in Lyra, which, it appears, is composed of concentric ovals of stars and nebulous stuff, so arranged that we must believe they are intimately associated in a most wonderful community.[D]The following extract from a letter by Bessel to Humboldt, written in 1844 (see "Cosmos," vol. iii, p. 186), is interesting, in view of the discoveries made since then: "At all events I continue in the belief that Procyon and Sirius are true double stars, consisting of a visible and an invisible star. No reason exists for considering luminosity an essential property of these bodies. The fact that numberless stars are visible is evidently no proof against the existence of an equally incalculable number of invisible ones. The physical difficulty of a change in the proper motion is satisfactorily set aside by the hypothesis of dark stars."[E]I should, perhaps, qualify the statement in the text slightly in favor of a lunar lady to whom Mr. Henry M. Parkhurst first called my attention. About nine days after new moon a rather pretty and decidedly feminine face appears on the western half of the disk. It is formed by the mountains and table-lands embraced by the Sea of Serenity, the Sea of Tranquillity, the Sea of Vapors, etc., and is best seen with the aid of an opera-glass of low power. The face is readily distinguishable on Rutherfurd's celebrated photograph of the full moon. It is necessary for this purpose to turn the photograph upside down, since it is a telescopic picture, and consequently reversed. The crater Tycho forms a breastpin for the lady, and Menelaus glitters like a diamond ornament in her hair, while the range of the Apennines resembles a sort of coronet resting on her forehead. This same woman in the moon, it appears, was described by Dr. James Thompson years ago, and, for aught I know, she may be the Diana to whom Herrick sang:"Queen and huntress chaste and fair,Seated in thy silver chair,Now the Sun is laid to sleep,State in wonted manner keep.Hesperus entreats thy light,Goddess excellently bright."[F]There are other uses to which such eye-glasses may be put by sky-gazers. I habitually carry a pair for studying clouds. It is wonderful how much the effect of great cloud-masses is heightened by them, especially when seen in a bright light. Delicate curls and striæ of cirrus, which escape the uncovered eye in the glare of sunlight, can be readily detected and studied by the use of neutral-tinted eye-glasses or spectacles.[G]See "Consolations in Travel, or, the Last Days of a Philosopher"; Dialogue I.

[A]Let the reader remember that the distance between the two stars in the brim of the bowl of the Dipper is about ten degrees, and he will have a measuring-stick that he can apply in estimating other distances in the heavens.

[B]A similar calculation of the internal appearances of the Hercules cluster, which I made, was published in 1887 in the "New York Sun."

[C]The Henry Brothers have continued the photographic work described above, and their later achievements are even more interesting and wonderful. They have found that there are many nebulous masses involved in the group of the Pleiades, and have photographed them. One of the most amazing phenomena in their great photograph of the Pleiades is a long wisp or streak of nebulous matter, along which eight or nine stars are strung in a manner which irresistibly suggests an intimate connection between the stars and the nebula. This recalls the recent (August, 1888) discovery made by Prof. Holden, with the great Lick telescope, concerning the structure of the celebrated ring nebula in Lyra, which, it appears, is composed of concentric ovals of stars and nebulous stuff, so arranged that we must believe they are intimately associated in a most wonderful community.

[D]The following extract from a letter by Bessel to Humboldt, written in 1844 (see "Cosmos," vol. iii, p. 186), is interesting, in view of the discoveries made since then: "At all events I continue in the belief that Procyon and Sirius are true double stars, consisting of a visible and an invisible star. No reason exists for considering luminosity an essential property of these bodies. The fact that numberless stars are visible is evidently no proof against the existence of an equally incalculable number of invisible ones. The physical difficulty of a change in the proper motion is satisfactorily set aside by the hypothesis of dark stars."

[E]I should, perhaps, qualify the statement in the text slightly in favor of a lunar lady to whom Mr. Henry M. Parkhurst first called my attention. About nine days after new moon a rather pretty and decidedly feminine face appears on the western half of the disk. It is formed by the mountains and table-lands embraced by the Sea of Serenity, the Sea of Tranquillity, the Sea of Vapors, etc., and is best seen with the aid of an opera-glass of low power. The face is readily distinguishable on Rutherfurd's celebrated photograph of the full moon. It is necessary for this purpose to turn the photograph upside down, since it is a telescopic picture, and consequently reversed. The crater Tycho forms a breastpin for the lady, and Menelaus glitters like a diamond ornament in her hair, while the range of the Apennines resembles a sort of coronet resting on her forehead. This same woman in the moon, it appears, was described by Dr. James Thompson years ago, and, for aught I know, she may be the Diana to whom Herrick sang:"Queen and huntress chaste and fair,Seated in thy silver chair,Now the Sun is laid to sleep,State in wonted manner keep.Hesperus entreats thy light,Goddess excellently bright."

"Queen and huntress chaste and fair,Seated in thy silver chair,Now the Sun is laid to sleep,State in wonted manner keep.Hesperus entreats thy light,Goddess excellently bright."

[F]There are other uses to which such eye-glasses may be put by sky-gazers. I habitually carry a pair for studying clouds. It is wonderful how much the effect of great cloud-masses is heightened by them, especially when seen in a bright light. Delicate curls and striæ of cirrus, which escape the uncovered eye in the glare of sunlight, can be readily detected and studied by the use of neutral-tinted eye-glasses or spectacles.

[G]See "Consolations in Travel, or, the Last Days of a Philosopher"; Dialogue I.

Back to Index Next