God's glory in the heavens/Total Eclipse Of The Sun

by William Leitch

Solar Spots.

VII.
TOTAL ECLIPSE OF THE SUN.

When the alarm of an eclipse is given in a Hindu village, the whole population turn out to avert the impending calamity. The black disc of the moon, encroaching upon the bright surface of the sun, is believed to be the jaws of a monster gradually eating up the latter. Tomtoms are violently sounded, the air is rent with screams of terror and shouts of vengeance; and all this uproar is made with the hope of scaring away the dragon from his dreaded purpose. For a time their efforts are in vain. The glorious sun disappears gradually in the mouth of the voracious monster; but at last increasing din seems to effect its purpose. The monster appears to pause, and, like a fish that has nearly swallowed the bait, but, on second thought, rejects it, gradually disgorges the burning morsel. When the sun is quite clear of the jaws, a shout of joy is raised, and the villagers disperse with the pleasing satisfaction that they have done the luminary a good service. This is but a type of the human mind in its untutored state, when it is unable to rise to the conception of a God whose glory lies in the orderly and regular evolution of His works of providence.

The power of predicting the time of eclipses, has divested such phenomena of their terror. The most ignorant Hindu could hardly but be ashamed of his superstition, and have his faith in his tomtom shaken, if the astronomer told him, beforehand, the precise moment when the monster would come and depart. Eclipses, more than anything else, demonstrate the perfect regularity of the motions of the heavenly bodies, and of the wisdom of Him who so exquisitely adjusted to one another, all the parts of the celestial machine. No doubt, the whole nautical almanac, with its mass of figures, is full of predictions, which manifest an order equal to that indicated by eclipses. Still, an eclipse, with its imposing phenomena, proclaims, in the most emphatic manner, the marvellous order of the heavenly host. An idea of the extreme accuracy with which the moon's position, at any moment, can be predicted, may be formed from the keen dispute at present (1860) going on in the Academy of Sciences between Leverrier and M. Delauny, in reference to the lunar theory of the latter, as compared with that of M. Hansen, the Danish astronomer, to whom is due the merit of discovering the difference of density between the nearer and more distant hemispheres of the moon. The controversy turns on the value of a constant entering into the calculation, and the difference between the two views is only a space, represented by the one three-hundredth part of the moon's apparent diameter. Yet on these few seconds of space, depends the result of an important question, on opposite sides of which the chief astronomers of our day are ranged. The Astronomical Society of London have virtually given their decision in favour of Hansen, by crowning him with their highest award of the gold medal. They have recognised his lunar tables as the complete solution of the grand nautical problem of finding the longitude at sea. The problem consisted in merely assigning, with absolute accuracy, the place of the moon in the heavens at any given time. Hitherto this was not done, as the perplexing and complicated irregularities of the moon's motion, baffled all attempts to calculate her position with the requisite accuracy. There are, even still, some outstanding errors which are to be accounted for, but they are so small, that any further approximation would practically be of no service to the mariner.

Every time the sailor takes a lunar with his sextant, he has a practical illustration of the triumphs of astronomy, in assigning the exact place of the moon at any moment in the heavens. Still, every mind must feel the more startling effect produced, when, in an eclipse of the sun, the first impact of the moon coincides with the very beat of the clock predicted by the astronomer; and predicted, too, not as an empirical deduction from previously observed regularity but as the result of the all-pervading force of gravitation, which not only produces the most bewildering inequalities, but furnishes, by its simple law, a key by which they may be all reduced to the most wonderful symmetry and order.

We have, however, on the present occasion, taken up the subject of eclipses, not so much with the view of illustrating the accuracy of astronomical calculations, as of turning the attention of our readers to the physical aspects of the total eclipse on the 18th of July 1860. No total eclipse has been witnessed in these islands for several generations. The last observed at Greenwich, was in 1715; and there was an interval of 375 years between this and the previous one. The chance of a person ever witnessing in his lifetime a total eclipse in any given spot of the earth's surface, is exceedingly small. The shadow forms only a narrow band on the earth's surface, and though that strip of darkness will cross Europe six times during the remainder of the present century, yet comparatively few places will enjoy the spectacle. It is certain that none of the present inhabitants of the British Isles will ever see a total eclipse, if they do not move beyond their own shores. But if the shadow does not come to us, we have the alternative of going to the shadow.

It may, however, be asked. Is it worth while to go much out of one's way to enjoy the spectacle? We have seen eclipses very nearly total, and we can readily conceive one that is absolutely so. Would it, then, really reward one to travel far to behold a sight which may differ so little from what we have already seen? We can give a very decided answer to this question. No approach to totality can give the slightest conception of the effect produced, the instant that the last thread of light is extinguished. The light of the sun is so intense, that while the slightest part of the disc is visible, the darkness is by no means alarming. The eclipse of 1857, which was nearly total, gave great disappointment to many who were led to expect something very appalling. Accounts of total eclipses were previously given, and it was a natural and popular expectation, that one so nearly total would produce effects very similar. But such was not the case. The darkness was no greater than that often produced by a passing cloud, and, in the case of many, the eclipse occurred without being in the least noticed. Partial and annular eclipses are now regarded as matters of mere curiosity, and a momentary glance upwards is regarded as all that is demanded in the way of attention. It is far otherwise with the total eclipse. The gradual creeping of the moon over the disc of the sun, gives no preparation for the grand final effect when the last ray is quenched. It is felt not to be a matter of gradation, so frightfully sudden is the darkness. There is no comparison between a man nearly drowned and drowned altogether, or between a man half over a precipice and over altogether; so there is no comparison between a nearly total eclipse and one absolutely total. As it is the last straw that breaks the back of the camel, so it is the extinction of the last line of light that produces the darkness that may be felt; and the "feeling of the darkness" is hardly a metaphor, as the borders of the terrible pall thrown over the earth can be actually seen swiftly floating past in the air.

In these days, when the passion for travel is so strongly developed, people are ready to go any distance to experience a new and strong sensation. They do not scruple to traverse the Atlantic, that they may gaze on the Falls of Niagara, or shoot the rapids of the St Lawrence; but such sights are not to be compared to a total eclipse, if measured by the power of stirring strong emotion. In an eclipse, all things combine to deepen the effect; there is nothing out of keeping with the grandeur and awfulness of the spectacle. In viewing the Falls of Niagara, there is much to tone down the feelings of awe and wonder. Familiarity has destroyed man's reverence; merry, laughing, picnic parties dispel the charm. Blondin exhibits his tight-rope feats in their presence. The very birds despise their terrors, and dash heedlessly into the spray, to catch the stupefied fish as they come tumbling down the liquid arch. The descent of the rapids of the St Lawrence, however daring the exploit may at first seem, fails, from the requisite accessaries, to produce a very powerful sensation. When shooting the Long Sault, or even the Lachine, or the Cedars, there is no overpowering feeling. The Indian at the wheel, with his imperturbable matterof-fact every-day expression; the old traveller, not caring to rise from the breakfast-table to look out on the tumultuous rush of waters; the air of security around, all combine to break the spell of that wonderful feat. It is quite different in the case of the total eclipse. All nature sympathises with, and enhances your feelings of awe and mysterious apprehension. The earth, seas, and sky assume a lurid, unnatural hue. An unearthly silence is felt at the moment of totality. Every living thing catches the influence, and cowers under the great blank in the heavens. Beasts of burden lie down with their loads on the road, and refuse to move on. Swallows, in their bewilderment, dash against the walls of houses, and fall down dead. The dog drops its bone from its mouth, and does not venture to seize it again till the light returns. Chickens seek the shelter of the parent wing; and even ants halt in their tracks with their loads, and remain immovable till the shadow is past.

With such accessaries as the above, it cannot be wondered at that, in the case of man, however impassive his nature may be, a total eclipse never fails to produce feelings of mysterious awe. The most learned savant, as well as the most unsophisticated peasant, confesses to such feelings. It is, however, when men are massed together, that the finest opportunity is afforded for watching the psychical effects of an eclipse. Such an opportunity was enjoyed by the French astronomers, when observing the total eclipse of 1842 at Perpignan. The observers were stationed on the ramparts with their instruments; the soldiers were drawn up in a square on one hand, and, on the other, the inhabitants were grouped on the glacis, so that the station commanded the full view of twenty thousand upturned faces. The astronomers did not fail to watch the phases of feeling in the crowd, as well as those of the eclipse. The moment that the people, with smoked glasses to their eyes, marked the first indentation in the sun's disc, they raised a deafening shout of applause, much in the way in which they would salute a military hero, or a popular actor. The moon gradually crept over the sun, and, for a considerable time, there was nothing observable but the ordinary loquacity of a French crowd. As the eclipse drew towards totality, the murmur of twenty thousand voices rapidly increased—each telling his neighbour of the strange feelings coming over him. Suddenly, the last filament of the sun's disc was covered, and, at that moment, a deep prolonged moan, as from one man, arose from that vast crowd. It was like the stifled groan of the multitude witnessing a public execution, at the moment that the axe or the drop falls. The moan, however, did not mark the climax of high-strained feeling. The dead silence that ensued was the culminating point. Not a whisper was heard, not an attitude was changed, as with the rigidity of a statue each man stood and gazed upwards. So unearthly was the silence, that the beat of the chronometers was heard with painful distinctness. The heart of the universe seemed to cease its throbbings. Nature had fallen into a state of syncope. For two and a half minutes this dreadful pause continued. At the end of this period a thread of light burst forth; the tension was at once relieved, and one loud burst of joy rent the heavens. The people could not restrain their transports of happiness, now that the dread, undefinable woe had passed over. They did not care now to look at the final phase of the eclipse, as the darkness wore off; they had beheld the crowning spectacle; they would not weaken the impression by looking at the partial obscuration, and, soon, the whole crowd melted away—leaving the astronomers to continue their observations alone.

We have seen how the eclipse told upon a French crowd, noted for its impressible and demonstrative character. But there were also numerous illustrations of its power over individuals. Take one as a specimen:—A young boy, on the same occasion, was herding a few sheep in a lonely heath, under a cloudless sky; he felt a strange darkness coming over the face of nature, and at the moment of totality, he fled towards home, sobbing piteously. Before he reached the door, the sun burst forth, and in the transport of his joy, he clapped his hands, exclaiming, "Beautiful sun! beautiful sun!"

We have viewed the total eclipse merely as a spectacle of surpassing grandeur; but it is one, too, of the greatest scientific interest, as throwing unexpected light on the physical constitution of the sun—

"Who could have thought such darkness lay conceal'd
Within thy beams, sun! or who could find.
Whilst fly, and leaf, and insect stood reveal'd,
That to such countless orbs thou mad'st us blind!
Why should we then shun death with anxious strife?
If light can thus deceive, wherefore not life?"

If night can give us a surprise by revealing countless worlds, the eclipse can also surprise by revealing a new glory of the sun. When the totality is complete, a corona bursts out around the black circle, like the glory that surrounds the heads of saints in the pictures of the old masters. This corona has usually been observed to consist of two zones or concentric strata. The innermost is the brighter of the two, and the light is nearly uniform. The outer and fainter zone is diversified with radiating beams. In consequence of the light of the corona, the darkness is by no means so great as that of night. The degree of obscuration is best measured by the number of stars visible. In all the authentic accounts of total eclipses, none but the brighter stars have been seen.

The most remarkable and baffling phenomenon, is the rose-coloured prominences seen in the innermost and brighter zone. They affect curious shapes; one, seen in the eclipse of 1851, has been designated the boomerang, another, the balloon. Some have been compared to the teeth of circular saws, others to the flames issuing from the top of a burning house, and driven aside by the wind.

The most important inquiry that suggests itself is, "Does this corona belong to the sun, the moon, or the earth?" This point has been keenly disputed; but the general belief is that it is an appendage of the sun. Father Secchi, to whose discoveries in regard to the nature of the moon's surface allusion has been made above, is disposed still to refer the phenomenon to the moon, and to explain it by means of his discoveries. It is a much more pro

Plate III

TOTAL ECLIPSE OF THE SUN

bable supposition that the corona is the atmosphere of the sun extending beyond its luminous disc, and that the red flames are substances floating in that atmosphere. In ordinary circumstances, the photosphere of the sun, or luminous envelope, is so overpowering, that the corona and the prominences are invisible. When, however, the eye is protected by the moon covering the luminous disc, they are at once revealed. No plausible theory has yet been given to explain the nature of the red flames. Some have attempted to trace a coincidence between the position of the flames and that of the dark spots of the sun; and it has been conjectured from this, that these dark spots are funnels in the luminous envelope, through which inflammable gases rise, and are burned in the region of the corona or atmosphere, where they appear as red flames. Others hold that the prominences are only the crests of the waves, or faculæ of the photosphere. The truth is, that we have almost no ground whatever, as yet, on which to base a theory. It was thought that during the last eclipse of 1851 several points would be set at rest; but the evidence was very conflicting, arising very much from the flurried state of feeling caused by the startling character of the phenomena, and their very brief duration. European astronomers are looking forward to the eclipse of the present year (1860) with eagerness, as it is confidently expected that it will be conclusively settled whether the corona and red prominences really belong to the sun or the moon; and, for this purpose, attention will be directed to two points in the phenomena—first, whether the corona retains its symmetry, or continues concentric with the black circle of the moon during the totality j and, secondly, whether, during the same period, the red flames change their position on the circumference of the moon. If there be a want of symmetry, and if the flames change their place, the evidence is conclusive that the appendage belongs to the sun.

Another point of interest will be the search for the newly-discovered planet Vulcan. It is expected that it will be readily found, from our knowlege of its approximate place.

To make amends for the imperfection of the testimony of the human eye in such unusual circumstances, it is intended to employ an artificial substitute, which wall record the impression with due calmness and fidelity. This is to be done by applying a sensitive photographic surface to the telescope, instead of the human retina. In other words, photographic pictures of the eclipse are to be taken, and under Mr De La Kue's superintendence, we may expect all that skill and experience can effect We are persuaded that many, beside professed astronomers, will seize this opportunity of beholding the grandest spectacle in nature. And why should they not? It is not a matter specially belonging to the astronomer. It involves no profound calculations, nor demands any delicate astronomical methods. It is simply a physical phenomenon, which any intelligent observer can appreciate as much as the astronomer. Indeed, the astronomer with all his imposing instruments, has, as yet, contributed little more than any one might have done with the use of his naked eye. Any one who goes merely for the enjoyment of the spectacle, should discard all scientific pretensions, and abjure the use of instruments. The time of observation is so brief, that the attention would be distracted and the enjoyment destroyed by attempting to employ any optical appliances.

The most accessible part of the eclipse's track is in the north-west of Spain. The centre of the shadow first touches the coast about Santander, and crosses the peninsula nearly along the valley of the Ebro. The French astronomers have selected the lofty mountain of Moncayo, as being in the very centre of the shadow, and enjoying a climate that precludes all fear of disappointment. There is, however, no need to climb a mountain to enjoy the spectacle to advantage. The mere amateur will have much more scope for observation in the neighbourhood of a populous town. Perhaps the best for this purpose is Vittoria. The traveller reaches Bayonne from Paris by railway the whole distance, and the distance from Bayonne to Vittoria across the Cantabrian Pyrenees is only about twenty-five miles, the journey being performed by diligence. The eclipse is also total at Pampeluna, Burgos, Santander, Bilbao, Eeynosa, all in the same region. The Spanish Government have promised every facility to travellers, and, notwithstanding the Carlist insurrection in the district, there is little fear of political discomfort. Mr Brassey with his army of navvies is busy as the pioneers of civilisation, in the valley of the Ebro. He and Mr Vignoles, the engineer of the railway in progress, have generously offered any aid in their power to travellers. It is understood that the Admiralty are ready to put a steamship at the disposal of such' observers as wish to go by sea, and to land at Santander. The rare opportunity is thus afforded of combining a visit to one of the most interesting regions of the earth's surface, with the sight of the grandest spectacle the heavens can present.