act v., scene I. Romeo and Juliet, act iii., scene 5. Cardinal Wolsey in prospect of his disgrace, says:— "I shall fall Like a bright exhalation in the evening, And no man see me more."- They are conceived to be drawn from the sky by music : To hear the sea-maid's music." -Midsummer Night's Dream, act ii., scene 2. At the destruction of Troy, as it were the mirror of their brightness, "The skies were sorry, And little stars shot from their fixed places, When their glass fell wherein they viewed their faces." See also Henry IV., act i., scene I; Venus and Adonis, stanza 138. "This shower Makes me more amazed Than I had seen the vaulty top of heaven Figured quite o'er with burning meteors."-Act v. sc. 2. In the first part of Henry IV., Glendower says: "At my nativity, The front of heaven was full of fiery shapes, Of burning cressets. The heavens were all on fire."-Act iii., scene 1. In King Richard II.:— "Meteors fright the fixed stars of heaven: The pale-faced moon looks bloody on the earth."—Act ii., scene 4. Locrine speaks of Mighty Jove, the supreme king of heaven, That guides the concourse of the meteors, And rules the motion of the azure sky."-Act iv., scene 1. The last passage to be produced from Shakespeare is from Love's Labour Lost, where Biron speaks thus disparagingly of astronomers : "These earthly godfathers of heaven's lights, That give a name to every fixed star, Than those that walk, and wot not what they are." He may be forgiven this, however, in consideration of the splendid eulogy on women, which he afterwards delivered-a subject on which he was more at home. True it is, nevertheless, that we could have dispensed with some of the work of these modern " godfathers"; and our globes and star-maps would be none the worse for ceasing to exhibit so many memorials of their officiousness and bad taste. "SPOTS IN THE SUN." To the Editor of the Times. Sir,-Among the astronomical observations upon record which have not as yet received a satisfactory explanation are those relating to spots upon the sun's disc, which have traversed it much more rapidly than the ordinary solar spots. In several cases these quickly-moving spots are described * I.e. Lights. as round, black, and sharply defined, like the planet Mercury, in transit, and hence the suspicion has arisen that one or more planetary bodies are revolving round the sun within the orbit of Mercury. M. Le Verrier, from theoretical considerations founded upon an unexplained motion in the line of apsides of this planet's orbit, has inferred the existence of a zone of asteroidal bodies within it. I have lately examined these observations with the immediate object of ascertaining whether it were possible to obtain a clue, however rough, that might lead to a rediscovery-on the supposition that an unknown planet exists at no great distance from the sun. In more than one instance the observations appear to refer rather to a comet than to a planetary body, and the bright comet of 1819 would seem to have been remarked in its passage over the sun's disc at the end of June by Canon Stark at Augsberg, and probably by Pastorff, near Dresden (though his observation is confused). But, on the other hand, it appears highly improbable that a comet projected upon the sun's disc would present the round, welldefined figure which several observers have noted, and particularly so that it would appear black like the planet Mercury when passing over the sun. It is incredible that so many persons can have been deceived as to the rapid motion of these suspicious objects, and the only conclusion that we can arrive at, unless the observations are altogether rejected (quite an inadmissible proceeding), appears to be that we have not yet brought into harness all the inferior planets that exist. In the course of my enquiry I have only met with one instance wherein there appears any ground for a prediction which might possibly lead to the recovery of the object to which the observations relate. Small, black, circular, well-defined bodies are reported to have been upon the sun's disc, by Dr. Lescarbault, at Orgeres, in France, on March 26, 1859, and by Mr. Lummis, at Manchester, on March 20, 1862, and it is a suspicious circumstance that the elements as regards the place of the node, or point of intersection of the orbit with the ecliptic, and its inclination thereto, as worked out by M. Valz, of Marseilles, from the data I deduced from a diagram forwarded to me by Mr. Lummis, are strikingly similar to those founded by M. Le Verrier upon the observations, such as they were, of Dr. Lescarbault. It is true if the place of the node and inclination were precisely as given by this astronomer, the object which was seen upon the sun's disc on the 26th of March could not have been projected upon it as early as the 20th of March. But, considering the exceedingly rough nature of the observations upon which he had to rely, perhaps no stress need be placed upon the circumstance. Now the period of revolution assigned by M. Le Verrier from the observations of 1859 was 19.70 days. Taking this as an approximate value of the true period, I find, if we suppose 57 revolutions to have been performed between the observations of Dr. Lescarbault and Mr. Lummis, there would result a period of 19.81 days. On comparing this value with the previous observations in March and in October, when the same object might have transited the sun at the opposite node, it is found to lead to October 9, 1819, as one of the dates when the hypothetical planet should have been in conjunction with the sun. And on this very day Canon Stark has recorded the following notable observation :-" At this time there appeared a black, well-defined. nuclear spot, quite circular in form, and as large as Mercury. This spot was no more to be seen at 4.37 p.m., and I found no trace of it later on the 9th, nor on the 12th, when the sun came out again." The exact time of this observation is not mentioned, but appears likely to have been about noon, one of Stark's usual hours for examining the solar disc. Hence I deduce a corrected period of 19812 days. If such a planetary body exists, on the supposition that it was remarked upon the sun in 1819, 1859, and 1862, this period would probably not be much in error ; and if we suppose the orbit to be circular or nearly so, with the approximate knowledge we have of the place of the node and inclination of the orbit, we may venture upon a prediction of the times of the greatest elongations from the sun eastward and westward, and the positions of the hypothetical body at the times. I have before me places so calculated for the times of the greatest elongations during the next few months, upon which it is proposed to institute a search at this Observatory, using the same means by which we, succeeded in bringing out the first comet of 1847 near its perihelion, at noon-day, and less than three degrees from the sun's limb. I refrain, however, from giving publicity to these predictions, in the fear of causing a number of observers to lose much time in searching for a body, which may have no existence except in my own imagination. I will, nevertheless, suggest that on the 24th of March next a very close watch must be kept upon the sun's disc. With the period I have inferred a conjunction with the sun would occur about 10 a.m. on that day, but it will be desirable to extend the period of observation through the whole 24 hours, and on this account the aid of observers on distant meridians will be important. If the hypothetical body is not found upon the sun's disc at that time, it will be, I think, a sufficient proof that my surmises are incorrect. In the circumstances I have here described consists the only clue I have been able to discover to a possible recovery of one of these supposed planetary bodies. It is obvious that the object seen upon the sun in March cannot, with its apparent inclination of orbit, be identical with that seen near Midsummer, 1847, in the metropolis by Mr. Scott, the Chamberlain of London, and at Whitby by Mr. Wray, the eminent optician, nor yet that remarked by M. Coumbary at Constantinople in May, 1865. I am, Sir, your obedient servant, Mr. Bishop's Observatory, Twickenham : J. R. HIND. October 18. NOTES ON THE WONDERS AND BEAUTIES OF THE STARRY HEAVENS. By C. GROVER, Assistant to John Browning, Esq., F.R.A.S. No. 5.-THE ANNULAR NEBULA IN LYRA. About 6° south of Vega, and a little to the left when on the meridian, are two tolerably bright stars rather more than 2° asunder. The preceding and more elevated star is 6, the following one is y; and, though both are marked third magnitude on the maps of the S.D.U.K., ẞ is a well-known variable, and y is strongly suspected of the same peculiarity. Of this we may have more to say hereafter; for the present we only refer to them as pointers to an object well-worthy to take rank as one of the most noteworthy of the celestial wonders. A little south of the line joining these two stars, and nearer 3 than y, a small telescope enables us to discover a minute roundish nebula. I have thus seen it tolerably welldefined and very like a planetary nebula in a 2-inch achromatic. With a 4-inch silvered glass speculum the elliptical figure and central opening are distinctly visible, with a 6-inch speculum it gains in beauty and interest, the faint illumination of the interior and the irregularities of the outer margin are just perceptible. Even with this small aperture Notes on the Wonders and Beauties of the Heavens. 259 the light is evidently mottled and distinctly different from the milky nebulosity of the great nebulæ in Andromeda and Orion. In the 12inch speculum many details of great interest become visible. The faint nebulosity of the interior is seen to be crossed by four brighter streaks lying in the direction of the longer axis; three of these are about equal in distinctness, but the second streak from the preceding internal edge of the ring is obviously the brightest. When best seen, these details always leave the impression on my mind of being more remote than the ring itself, and this idea is supported by the fact that four or five faint filaments or streams of light are seen extending from both ends of the ellipse as if they were continuations of those within its interior, thus leading to the supposition that the bright ring which is alone visible in small instruments, is seen projected a still more remote, stratified nebulosity; and this opinion is strengthened by the fact that although there are several irregularities about the exterior of the ring's minor axis, they are very faint and unimportant compared with those which appear to traverse the interior and extend beyond either end. The ring itself when seen with a low power and large aperture exhibits a surprising degree of brilliancy; indeed, when the power is insufficient to reveal the figure of a nebula, it might easily be confounded with some of the tolerably bright stars which appear with it in the same low power field, and with moderate powers its brightness is such, especially about the extremities of the minor axis of the ellipse, as to give a false impression of resolution. Indeed, it has been announced as resolved into stars by several observers of considerable eminence in observational astronomy. These observations, however, are in direct contradiction to the evidence of the spectroscope, which in the hands of an observer worthy of equal confidence, has distinctly shown this object to have a gaseous constitution. Notwithstanding this, I was strongly inclined, from its exceptional brightness and mottled appearance in the smaller instruments I had previously employed, to believe in its stellar composition, and I had great hopes that the power of the 124-inch speculum would reveal the "star dust" described by other observers. I have therefore on several occasions, scrutinised the nebula when the absence of the moon, a clear sky, and its position on or near the meridian, allowed it to be seen to great advantage, at such times being steadily kept in view by the equable movement of the equatorial clock, it presented a superb spectacle. But with the utmost care and attention, and the application of considerable magnifying powers, I could never detect the least indications of a stellar composition, it simply appeared as nebulous as ever. I do not percieve with this aperture any appearance of the fluctuation of light or twinkling appearance which has been described by some observers, and which would seem to be caused by insufficient optical power, as I have sometimes noticed an unsteady appearance when using a small speculum; an analagous phenomenon is perceived when observing a star so minute as to be only just within the power of the aperture in use, which will appear fluctuating or seen by glimpses. With this every observer is familiar. A small star follows the nebula on an angle of 96°, and at a distance of rather more than the breadth of the ring as determined by Sir J. Herschel, he gives it eleventh magnitude, but it appears to me, as it does to several observers, much smaller. I find it but just steadily visible in a 6-inch speculum. This star, which is shown in most of the copies of Sir John's drawing to be found in every recent astronomical work, has been suggested as a convenient fixed point from which to obtain a set of micrometrical measures of the internal and external dimensions and positions of the centre of the nebula, so as to afford a ready means of detecting any changes of form, size, or position, which might hereafter take place. This very desirable information is not, however, so easy to be obtained, many serious practical obstacles standing in the way of its accomplishment. For instance, the small instruments which give the best outline of the nebula scarcely show the star, and with larger apertures the star is of course well seen, but the outline of the nebula becomes more and more irregular with increasing powers, and again the illumination of the field necessary to render the micrometer webs visible seriously interferes with the distinct perception of so delicate an object. There are four other much smaller stars nearer the nebula than the one just mentioned, one of these lies at a rather less distance from the opposite edge of the ring, two others forming a neat pair are very near its northern margin, and another about as near the southern edge; these very delicate objects are visible with a power of 300 on the 124-inch speculum. The Annular Nebula in Lyra is by far the largest and most conspicuous representative of this not very numerous class of objects. Two other examples, figured by Sir John Herschel in his "Cape Observations," are well worthy of notice as exhibiting the different appearances we might expect in such objects, arising either from increased distance smaller dimensions, or inferior optical power. One of these is situated is R. A., 17h. 19m., and 23° 37' south declination, and is therefore a little north of the centre of a line joining the two fifth-magnitude stars 44 and 50 in Ophiuchus. It is described as "exactly round, pretty faint, 12" in diameter, well terminated, very little cottony at the edge, with a decided darkness in the middle, few stars in the field, a beautiful specimen of the planetary annular class of nebulæ." Any observer who has seen the nebula in Lyra with a small telescope, will at once perceive that, as regards the general appearance, this is an exact description of that object. The other example has R. A., 17h. 10m., and south declination, 38° 18', and therefore only barely rises above our horizon; it is described as 66 a delicate, extremely faint, but perfectly well-defined annulus, 15' 20" diameter, the field crowded with stars, two of which are on the nebula." These stars are shown in the figure at the opposite sides of the minor axis, and therefore coincide with the brightest parts of the ring of the nebula in Lyra. "The interior, indeed, appears to be devoid of any illumination, but the object is so faint that a nebulosity filling in the centre and bearing no greater proportion in respect of density to the ring, than in the case of 57 M., could not be perceived." It is worthy of remark, as showing how little many book illustrations resemble the objects intended, that in "Guillemin's Heavens," 2nd edition, page 335, both these objects are engraved, the former with a perfectly black centre, and the latter with an interior distinctly nebulous, in direct contradiction to the figures and descriptions of Sir John Herschel. In the "Cape Observations," he remarks, "it is not impossible that the real constitution of these bodies may be that of hollow spherical or elliptical shells, of which the borders appear brighter than the interior by reason of the greater thickness of the luminous matter, or starry stratum, traversed by the visual ray." The tenuity of the ring, as well as the feebleness of the central illumination, will of course in our hypothesis be proportioned to the thinness of the shell; and the law of the degradation of its light will be determined by the ratio of the radii of its inner and outer surfaces, as well as by the law of density of the strata of which it consists. |