that the surface of the moon is, in many parts of it, thickly studded with groups and ranges of lofty volcanic hills, the appearance of which very closely resembles that of Vesuvius or of the Campi Phlegræi in the neighbourhood of Naples, or the long line of extinct volcanos in Auvergne, and on the southern side of the Cevennes in France. A picture of the one would give a not inadequate conception of the other. This then being the case with the moon, it is by no means an uncommon thing to see her black contour in her stately and half-mysterious march across the bright face of the sun, somewhat irregular and jagged; but, although the configuration of the moon's surface is now perhaps better known than that of the interior of Africa, we believe that no range of lofty hills exists on our satellite such as could produce the phenomenon of the bright beads, as described by Mr. Baily. However, be these beads what they may, and however caused, it is quite certain that this fortunate observation excited the attention of astronomers to the more careful scrutiny of solar eclipses in future. We shall only add, that on the occasion of this annular eclipse at Jedburgh the light which emanated from the thin, thread-like, luminous, uneclipsed ring of the sun was quite sufficient to obliterate, or prevent all those grand, and, it may be said, almost terrible phenomena which in due course we shall have occasion to describe as accompanying an eclipse in its totality. Mr. Baily remarks that the light resembled that which is seen when the sun shines through a morning mist, the annularity lasting for nearly four minutes and a half. The thermometer fell three or four degrees. Two minutes before the annulus was formed Venus became visible. Gunpowder could not be fired when the heat from the uneclipsed annulus was concentrated upon it by a burning lens of three inches in diameter. Notwithstanding the partial gloom, the birds continued in full song, and a cock persisted to crow with all its might. Very different, as we shall see, were the effects at our station at Gujuli in 1860. had united the closely contiguous edges of the sun and moon, did not appear. Warned by his own experience, and by the record how a century before, and on an occasion similar to the present, Roger Cotes, the friend of Newton, had complained of being "opprest by overmuch company," ,"* Mr. Baily had requested to be left alone in one of the rooms of the University of Pavia. To his infinite astonishment, while watching the disappearance of the beads, he found his voluntary solitude suddenly broken by a tremendous burst of applause proceeding from the streets below, and, on taking his eye for a moment away from the telescope, he was himself "electrified by one of the most brilliant and splendid phenomenon that can be imagined." He had expected to see round the dark moon, which now completely concealed the sun, nothing beyond something analogous to what he had seen at Jedburgh in 1836, viz., a narrow, circular band or riband of light, of no great brilliancy or extent. But he had not sufficiently estimated the effect of the still remaining light which emanated from the narrow, luminous ring of the annular eclipse at Jedburgh, in obliterating phenomena which, but for this residuary light, might have displayed themselves with far greater intensity. The unexpected phenomenon which had excited the applause in the streets of Pavia, and which the more calm astronomer confesses electrified himself in his solitude above, was nothing less than the sudden outburst of a crown of light surrounding the dark orb of the moon. Its breadth extended fully to that of one-half of the moon's diameter; the colour of the light was neither pearly, nor yellow, nor red, but of a pure white, and it seemed divided into rays. In some respects it seemed inimitable by any artificial contrivance, but it bore some resemblance to the "Aureole or "Glory," which in pictures is painted round the heads of the saints. We can fully appreciate the expression of Mr. Baily's surprise, that so obvious, sudden, and magnificent a phenomenon had not been adequately described in any previous account of a total solar eclipse. Six years elapsed before an opportunity presented itself to European astronomers for the re-examinaBut this sudden outburst of a luminous corona tion of the strange appearances observed by Mr. round the dark orb of the moon was not the only Baily; and this was afforded by the occurrence of a unexpected phenomenon which the astronomer saw, solar eclipse visible throughout the north of Italy, or at all events now noticed, for the first time.† From and over a portion of Germany. On this occasion it the dark body of the moon, or it might be from the was fortunately not annular, but total. Mr. Baily now obscure photosphere of the sun behind it, there posted himself at Pavia, and the present Astronomer darted forth into the corona three luminous protuberRoyal, Mr. Airy, selected for his place of observation ances, or tongues, as it were, of coloured flame; their the summit of the well-known Superga in the neigh-colour was red, tinged with purple, or peach blossom, bourhood of Turin. This eclipse occurred on the 8th July, 1842. or perhaps more nearly resembling that celestial tint which sometimes reposes impatiently upon the snowy tops of the Alps at sunset. Mr. Baily took with him the same instrument which had disclosed to him the beads at Jedburgh. These mysterious tongues of coloured flame exAgain he saw the same phenomenon, just at the moment when the black moon was on the point of * See Philosophical Transactions for 1715. In Motte's Abridgment of the Philosophical Tran extinguishing the light of the bright sun. The sun actions, vol. i., page 268, the curious reader may find went out, as it were, not as an exquisitely thin and that Captain Stannyan, at Berne, in 1706, observed “a beautiful crescent, but in the form of a few brilliant, blood-red streak of light" in the corona, and that Halley detached, luminous beads; on this occasion, how-beads" in the next total eclipse of 1715. See pages 272, anticipated the observation of something like "Baily's ever, the interstitial black lines, which at Jedburgh 273, of Motte's Abridgment. 1 Jood Words, Sept. 1, 1507.] A JOURNEY IN THE SERVICE OF SCIENCE. tended into the corona through a space estimated at about one-twentieth of the moon's diameter; hence, if they belong to the sun they must have had one dimension of at least from thirty to fifty thousand miles! If they belong to the moon this magnitude would be reduced to perhaps eighty, or it may be, a hundred miles; we speak purposely in a loose approximation. We shall see in the sequel that modern astronomy has settled where they are, but not what they are; yet we are not without a reasonable hope that through observation made during a total eclipse, which will occur in less than thirteen months hence, perseverance, and science in her rapid progress, will disclose to us something definite regarding the natural history of even these unearthly fires so mystic and so remote. But of this also we shall speak much At present we more definitely in the sequel. shall only add that the light from the corona was sufficiently intense to render a candle, which Mr. Baily had lighted for the purpose of reading his chronometer, unnecessary. And now for how long does the reader imagine was the continuance of these wonderful revelations? In the brief space of two minutes and a half, they had come and they had gone; suddenly they came, and as 'suddenly they vanishedvanished from the sight "like an exhalation" or as a vision in a dream :-but not from memory. While Mr. Baily was thus engaged in making these observations at his room in the University of Pavia, the present Astronomer Royal, Professor Airy, was similarly occupied on the summit of the Superga. The Superga is the culminating point of an insulated knot of hills, rising some 800 feet above the valley of the Po, situated about five miles from Turin, and commanding a most lovely and extensive view over the plains of Piedmont. Mr. Airy appears to have selected it, among other reasons, under the hope that he might catch a glimpse of the rapid fight of the shadow of the eclipse over a widely extended and visible track of country. In this he was disappointed; for the day was gloomy, and it requires a bright and unclouded sky to see the mighty rush of that unearthly shadow speeding from height to height, or sweeping over the level fields, at the rate of some thirty miles per minute, up to the very feet of the observer, and then wrapping him and all things round him in a sudden and startling gloom. Upon the Superga were many spectators; but the Professor-thanks to the good feeling of his neighbours-was not like his great predecessor, Cotes, at Cambridge, opprest with overmuch company." At Mr. Airy's station, the darkness both before and during the totality seemed to have considerably exceeded that experienced by Mr. Baily at Pavia; indeed, the amount of darkness during an eclipse appears to be modified to a great extent by the meteorological circumstances of the atmosphere at the time. About two minutes before the commencement of the totality, the candle which stood lighted at Mr. Airy's side seemed to burn with an unnatural brilliancy. "A large cloud over our heads, whose appearance had not been particularly remarked, became, if pos- Mr. Airy saw nothing whatever of the "beads," Akin to the appearance of the proximity of the Such are the phenomena observed by these two Upon the return of the Astronomer Royal and Mr. Baily to London, it was natural that a very lively interest should be excited among men of science, and indeed among intelligent persons in * Transactions of the Astronomical Society, 1842. general, by the remarkable, not to say striking nature of the phenomena which they had described. The re-observation of the bead-like appearances by Mr. Baily, their non-observance by the Astronomer Royal, the unexpected dimensions and brightness of the corona, and beyond all, the record of the coloured flames or prominences, became the subjects of animated discussion among learned men. Notwithstanding the philosophy of Comte, at that time coming into fashion, that men act wisely and usefully when they confine their attention solely to what they see, and how and when they see it, it came from an irrepressible impulse of the mind, setting at nought and confuting this hard philosophy, that intelligent men began, and could not help beginning, to speculate earnestly and widely upon the causes of these strange and newly observed phenomena. Does the beautiful light of the corona arise from the reflection of the sun's light by a transparent atmosphere surrounding the sun's photosphere? If so, how enormous must be its extent, seeing that the light has been traced to a distance from the sun exceeding the half of its own diameter! And then, what are these mysterious coloured prominences like tongues of fire? Are they really flames? Are they solid ? Are they enormous masses of solar cloud floating in the lower portions of a solar atmosphere, and illuminated and coloured like terrestrial clouds at sunset? Or is it possible that they are appendages of the moon? And lastly, what are these luminous bead-like entities into which the last thread of solar light breaks up, just when the black moon is completing its obscuration of the sun? Are they the strugglings of the last of the sun's rays through interstices between some line of lunar mountains on the moon's edge? Are they entities at all, or is it possible that the telescope is at fault? These and other like questions formed, for many months, the staple of discussion not alone among astronomers, but they deeply interested other intelligent men who took pleasure in advancing or in watching the advance of physical knowledge. detailed lucidly and beautifully in Sir John Herschel's delightful volume, "Familiar Lectures on Scientific Subjects:" GOOD WORDS having had the honour of1 presenting most of them in their original and uncollected form to the readers of this periodical. It soon became known that on July 28, 1851-nine years, that is, after the Italian observations-there would be a total eclipse of the sun, visible throughout a considerable extent of Europe; and short as its duration must necessarily be, nevertheless lasting for a time sufficient for skilful observations. Maps of the path of the shadow of the moon were prepared, and a long and carefully adjusted string of questions was printed by order of the British Association, from which amateur observers and others would find abundant information and instruction how to proceed, and what phenomena were worthy of especial note. Sweden was fixed upon as containing the most accessible and advantageous localities for carrying on the observations, and various parties were organised, i comprising many of the ablest and most experienced of English observers. Among them we may mention the following names in alphabetical order :-Messrs. Adams, Airy, Carrington, Dawes, Hind, Lassell, | Robinson of Armagh, and Piazzi Smyth; an array o astronomical names more than sufficient to inspire all necessary confidence. To these we may properly add the well-known names of Mr. H. Fox Talbot, and of Mr., now Professor, Liveing, whose philoso sophical pursuits were directed rather toward physical than astronomical science. The Astronomer Royal on this occasion was accompanied by two assistants, Mr. Dunkin, of the Royal Observatory, and Mr. Humphreys. In order that the circumstances of the eclipse might be seen as much as possible under different points of view, Mr. Airy remained himself near the path of the centre of the moon's shadow, at Göttenburg; while his two coadjutors were despatched nearly to the two extreme edges of the shadow. Another reason for the separation was the advisability of making some preparation against the contingency of bad weather in any one locality. As the dark moon advanced over the face of the sun, Mr. Airy, who was provided with a telescope of 3 inches aperture, observed that the outline of the moon's disc was extremely jagged by mountainous elevations, and yet he says, "I saw the moon's serrated limb advance up to the sun's, and saw the With such knowledge as philosophers possessed in 1842, it was not then possible to give a definite and certain reply to many, or perhaps even to any of these questions; but then the discussion of them served to indicate the proper form of future observations; and as competent men quietly mused upon the strange sights which had been seen in Italy and at Jedburgh, the practical questions and cross-light of the sun glimmering through the hollows questions which probably it would be most advantageous to put to the sun and to the moon, on the occasion of the next total eclipse, began gradually to take a philosophical and definite form. And not only so, but there arose also another collateral advantage: the minds of practical observers became more intently set upon scrutinizing the body of the uneclipsed sun itself, the ultimate result in our day being an accession to our knowledge far beyond what in 1842 entered into the conceptions or the hopes of men. And should the reader desire to know what these accessions to our physical knowledge are, he will find many of them between the mountain peaks, and saw these glimmering spots extinguished one after another in extremely rapid succession, but without any of the appearances which Mr. Baily has described." With regard to the amount of darkness during the totality, Mr. Airy's account is that the chronometer face could not be read without the immediate proximity of a lantern; that a friend of his had great difficulty in finding the way to descend from an adjoining rock, and that he found it no easy matter to write the smallest memorandum even with the aid of the lantern. Moreover, in order to avoid confusion Good Words, Sept. 1, 1967.1 A JOURNEY IN THE SERVICE OF SCIENCE. and loss of time, when the time is so short, he recom- With reference to the corona, it was far broader Of coloured prominences there were several; one With respect to the visibility of the rushing motion Some cries of the birds were recognised by persons It is a circumstance both curious and noteworthy that Mr. Dunkin, who was observing near the edge of the moon's shadow, and in unfavourable atmospheric circumstances, saw the moon's edge advance over the sun without any serrated marks indicative of mountains, and yet the phenomena of "Baily's beads" were observed by him in all their brilliance. He says, "The only thing I can compare them with is a necklace of diamonds." There is one description of the motion of the shadow of the moon over the country, given by Captain Biddulph, R.A., which will probably be read with much pleasure, and with it we shall conclude for the present all further reference to this exciting phenomenon. "A * The direction of the passage of the moon's shadow was from N.W. to S.E. A gap in the clouds became first a blue purple, and Before we dismiss the account of this eclipse as: west, or the right hand, thus concealing that part of the prominence which was nearest to the sun, and then as the moon advanced to the left, or the east, it would uncover more and more of it, thus increasing its apparent altitude or length until the moment when the root of the prominence and the sun itself began to be disclosed; then all would soon be obliterated by the excess of light. It cannot be said that the observations of this eclipse of 1851 brought any large accessions to our positive knowledge either in a physical or an astronomical point of view; nevertheless, the experience gained even from imperfect results was at the time considered to be, and ultimately was proved to be, of the utmost importance in guiding future proceedings on similar occasions. For instance, the want of absolute measures made at the time, left Mr. Adams in some doubt as to whether the increase of the height of the coloured prominence mentioned in the last paragraph was precisely such as was due to the rate of the moon's motion over the sun's disc, and consequently there remained the same amount of doubt as to the certainty of the locality of the prominence itself. Here, then, was an indication of the necessity of contriving some means for exact measurements on a future occasion. Again, Mr. Fox Talbot, who observed this eclipse in Germany, threw out a suggestion that the origin of these rose-coloured flames, as possibly they might eventually be shown to be, was to be sought in some inflammable vapours proceeding from spots in the sun, as they are conventionally called, but which spots are in fact certain funnel-shaped holes or rents in the solar photosphere itself. This remark indicated the necessity of a careful scrutiny of the sun's body both before and after the eclipse. Lastly, a daguerreotype of the eclipse had been taken by Dr. Busch at Königsberg, which, imperfect as it was, held out the promise that records from the unimpassioned autographs of the sun itself might be more leisurely and calmly examined, than any instrumental observations of the phenomena themselves made by the human eye at a time when the mind of the observer could scarcely fail to be prejudiced, or excited and off its balance. Again the charmed cycle of about nine years was fast passing away, and the attention of astronomers was drawn to another total eclipse, visible on the 18th of July, 1860, not in Italy, as in 1842, nor in Norway, as in 1851, but on this occasion embracing for a longer or shorter duration almost the entire north of Spain. Under the auspices of the Astronomer Royal an expedition was in due time organised, comprising a considerable number both of amateur and professional observers. After the experience gained on the two former occasions it was reasonable to hope that the locality of the rose-coloured prominences would at length be finally established, and that some better information would be obtained relative to the origin of the beautiful radiations of the corona. With this view certain improvements were introduced into the form of the micrometer, or measuring instrument, and in particular a happy suggestion of Sir John Herschel's was adopted, whereby the sun's entire disc could be observed without the necessity of contracting, as heretofore had been necessary, the aperture of the telescope. Beyond all, great advances had been made in the art of photography as applied to autographic pictures of celestial objects, and especially in this country by Mr. Warren de la Rue, who by a rare combination of chemical, mechanical, and astronomical skill, had obtained photographic picture of the sun and the moon, possessing not only unrivalled beauty, but, what was of more consequence, an amount of accuracy which would bear comparison with result obtained by the most refined instrumental measurements. It was in fact proposed to attempt to photograph the corona and its appendages during the totality itself. At the instance of Mr. Airy, the Admiralty of that day devoted their noble troop-ship the Himalaya to the purposes of the expedition. Nothing was omitte which was deemed likely to conduce to the successful prosecution of the observations required. A code of instructions was drawn up, maps of the path of the moon's shadow were engraved on a large scale, and all the anticipated circumstances of the eclipse were described with a copious and precise detail. Among other arrangements, Mr. Hind, the superintendent of the Nautical Almanack, furnished a pictorial chart c the positions, in relation to the sun, of such planetand stars as it was presumed would become visible during the obscuration of the eclipse. The main object of the construction of this chart was to afford the means of detecting certain intra-Mercurial planets the existence of which had been suggested by M Leverrier, and especially a planet "Vulcan" which that eminent astronomer maintained had been observed in its transit over the sun's disc by M. Lescarbault. Beyond all other circumstances which promised favourably for the successful observation of thi eclipse was the existence of a railway, in process of construction from Bilbao to Tudela, across the shadow of the eclipse. It was rightly considered that such works in a country where roads were few, and accommodation and the means of transit scarce, would prove a circumstance of the utmost importance; indeed, but for the existence of this railway, and beyond all, but for the untiring zeal and unbounded liberality and intelligence of the engineer, E. Vignolles, Esq. F.R.S., the whole expedition must have been thrown into almost inextricable difficulties. (To be continued.) C. PRITCHARD. *Cape Observations. Appendix. |