Art. LIX.—The Total Eclipse of the Sun of the 9th September, 1885; being a Digest of the following Communications to the Institute on the subject:—
A.—On the Total Eclipse of the Sun, 9th September, 1885. By John Meeson, B.A. Read before the Nelson Philosophical Society, 2nd November, 1885.
B.—On the Total Eclipse of the Sun, 9th, September 1885. By the Right Rev. Dr. Suter, Bishop of Nelson. Read before the Nelson Philosophical Society, 2nd November, 1885.
C.—On the Total Eclipse of 9th September, 1885, as seen at Tahoraite. By John Goodall, M.I.C.E. Read before the Hawke's Bay Philosophical Institute, 14th September, 1885.
D.—On the Total Eclipse of the Sun, 9th September, 1885. By A. S. Atkinson. Read before the Nelson Philosophical Society, 2nd November, 1885.
E.—On the Total Eclipse of the Sun, 9th September, 1885. By Dr. Hudson. Read before the Nelson Philosophical Society, 2nd November, 1885.
F.—Observations on the Solar Eclipse of 9th September, 1885. By A. Coleman. Read before the Nelson Philosophical Society, 2nd November, 1885.
Plates XIV., XV., XVI.
[Note by the Editor.—The section of the moon's shadow, as it swept over the earth's surface, was in the shape of an ellipse, 190 miles in length by 90 miles in width. The only land crossed by the shadow was that part of New Zealand lying in the vicinity of Cook Strait, so that the total phases could only be observed there; the line of centrality sweeping in the shape of a curve from a point half-way between Australia and New Zealand, where the sun was rising at the time of totality, to a point between Cape Horn and the South Pole, latitude 75° S., where the sun was setting at
the time of the eclipse. In New Zealand, the line of centrality passed through West Wanganui, Collingwood, D'Urville Island, and the Wairarapa, leaving the land on the East Coast at Castle Point. At all places along the line of centrality, the duration of the total phase was computed at 1′ 58″, the time being a few seconds longer towards the east. At Castle Point, the totality commenced at 7h. 35m. 12s. a.m., New Zealand mean time; at Wellington, at 7h. 35m. 4s.; and at Nelson, at 7h. 34m. 14s. Observations of a more or less scientific nature were taken at a number of places—Tahoraite, Wairarapa, Manawatu, Wellington, Picton, Nelson, Collingwood, etc.; and a large number of papers and communications were made to the public press, and to various scientific societies, conveying the impressions of the various observers.
From a review of the observations that were made, the following conclusions were arrived at:—
“Scarlet prominences were only moderately developed, and were clustered chiefly at the equatorial and polar regions of the sun. The best observers agree that the corona had a very irregular outline, and was most continuous and vivid close to the sun's limb, having the longest expansion reaching to nearly two diameters from the western equatorial region. This large expansion appears to have had a strongly marked spirally twisted structure, while all the other appendages consisted of radiating pyramids. No laminated structures appear to have been observed in any part of the corona.
“Most observers agree in describing an intensely brilliant flash or meteor, lasting for two seconds, at the commencement of totality on the eastern side of the sun, and exactly over the position of a large sun-spot that was just coming into view at a few degrees south of the sun's equator. This flash is described as having looked like a large electric lamp suspended at a little distance from the moon's edge. At the close of totality another flash, similarly bright, but not so large and pointed, was seen on the western limb of the sun, in a position corresponding with a large sun-spot that was within 1′ of arc of passing over the sun's edge.”*]
Mr. John Meeson, B.A., gives the following general description of the eclipse:—
“The weather was perfect, the sky almost, if not quite, cloudless, with a very light wind from the S.E.; a clear, moistureless, frosty air! My point of observation was my own garden at Woodstock, Stoke, whence, from 6.45 a.m., when the
[Footnote] * “Proc. Roy. Soc., London,” 19th November, 1885, “On the Total Solar Eclipse of September 9,” by Dr. Hector, F.R.S., dated 12th September, 1885.
sun—already partially obscured—rose from behind the north-eastern hills, until 8.30 a.m., by which time the moon had completely passed over the solar face, the view was continuous and uninterrupted. More perfect circumstances for making valuable observations cannot well be imagined; and a sight grander and more unique than the whole eclipse it is impossible to conceive. Even as the wind falls when the shades of evening close around, the very light breeze which had been blowing in the early morning gradually died away, and darkness increased. Birds ceased their twittering, all—at all events, except some paraquets, which were evidently much startled, and broke into the most noisy chattering as the sun disappeared, and flew away, it may be supposed, to their usual night haunts. Everything else became hushed; even the human voice had, or seemed to have, an unnatural sound. All nature seemed to bow its head, and stand in mute silence as the awful spectacle passed, and until the God of Day should again emerge from his temporary seclusion. The general appearance of things at the moment of totality, which was certainly not a period of complete darkness—for a soft and ‘dim, religious light’ was always present—was such as the observer can surely never forget. It was decidedly uncanny. The human face looked ghastly. The colours on mountain and field, on sea and sky, were weird, unearthly, and indescribable, such as one had never seen before. They had gradually deepened in hue as the eclipse proceeded, and just before totality the sky around the sun was of a dirty yellow, and quivering beams, of the colour of electric light, shot out from above and below the moon, giving it somewhat the appearance of a St. Andrew's cross with a circular centre.
“Generally speaking, during the sun's complete obscuration, the sky was of a mauve colour, except round about the luminary itself, where the intense brilliance of the silvery protuberances or the golden glory of the coronal rays diffused tints of dirty red and grey. The sea became black, the mountains across the bay iron-grey, while the sky above the latter assumed shades of dirty, ghastly yellow. A few patches of fleecy clouds hanging low over the sea took on the appearance of black cumulus heaps, and afterwards, on the emergence of the sun, donned garbs of varied colours. The lunar orb, during totality, stood out boldly, and round its limbs was a fine fringe of intense light, which glistened like diamonds; upon its surface a slight reflected light was clearly seen. After the eventful period of a minute and a few seconds had passed, there appeared, at the point of the moon's disc opposite to that which first obscured the sun—at the point, that is, where arose, as we shall afterwards see, the longest streamers of the corona and the highest prominences,—a growing effulgence of light, which rapidly intensified as we watched. The prominence seemed to swell and
bubble and boil like a spring of molten silver. This appearance was produced by the blending together of the large prominences and the sun's reappearing disc; and not for several seconds, perhaps, did the latter assert itself, assume its true shape, and, by its superior luminosity, cast the protuberance into obscurity, and substitute its ordinary beams for the temporary or temporarily-perceptible coronal rays. During the obscuration, stars were plainly seen by those whose attention was not already bespoken by something more unusual. I saw Jupiter very distinctly. The rushing of wind, as from all points of the compass, remarked upon by one of our local newspapers, I certainly did not experience. The fall of temperature along the belt of totality, instead of causing wind thitherwards, would rather operate to produce motion of the air in precisely the opposite direction. But, as already observed, there was really no wind at all, but over everything the stillness as of death.”
The Bishop of Nelson describes the eclipse as observed from a hill near Nelson:—
“The sensible progress of the eclipse at first seemed slow, but at the critical and crucial moment it appeared cruelly rapid. The body of the moon crept on over the left or western limb of the sun, and while it was about half over, there was a very sensible diminution in the light. It began to be a cold and silvery light, and the absence of yellow light seemed more and more marked, till the not unfamiliar lunar crescent-shape was assumed by the sun; and this stage was the period of quite a peculiar phenomenon in the appearance of the hills below the sun. Each one of the many rough furrows of valleys, divided by ridges of bush, became dark and black in shade; but each ridge was distinctly marked by a yellowish-green light, so remarkable as to form the subject of notice by me to the by-standers, who all acquiesced in the recognition of the decided and noticeable peculiarity of the appearance. It was most marked, and fortunately so much so as to be capable of reproduction. Possibly there may be a somewhat similar appearance under the crescent moon.
“As totality came near, and one's attention was confined almost exclusively to the sun, it seemed to me that the crescent was divided into one or two elongated portions of light, and then, subsequently, that these elongated portions were divided up into what reminded me of the cogs of a wheel, or rather the little blocks of different metal that are planted in the rim of the compensating balance of a good watch or chronometer. I suppose this appearance to be that described as “Bailey's beads.” They appeared to me to exist for only a very short time indeed, but they were distinct cogs of light, over little more than a third of the edge of the sun, on the eastern or lower side.
“It then appeared to me as if the sun, or dark body of moon,
were encircled with a brilliant ring at the time when, to use a common phrase, the sun “went out.”
“This corona, or ring of light, had time just to print its impression on the eye when two appearances made themselves manifest: First, the body of the moon started into rotundity— or, if I may use the word, globosity—from two … into three, from being a black disc, into a faintly but decidedly luminous globe, the effect, we are told, of earthshine on its surface. Earthshine in its effects is decidedly less evident than moonshine. (The second appearance is dealt with under the heading ‘Prominences.’)
“The darkness was not exactly that of night. As to the degree of light, it seemed to be paralleled by the amount of light diffused about when the moon is nearly half full; but the light that remained on this occasion was not that of the blue silvery moonlight, but of a neutral character, and the darkness seemed to have a palpability, if so it can be called. At the latter part of totality I turned to pick up the binocular, which I had discarded for the plain smoked glass guard, and was surprised then at the actuality of the darkness. I turned round, and caught sight of what made me look again, and I experienced a sensation to which I can only apply the epithet appalling.
“The glorious sign in the heavens shone forth on a yellowish-grey sky, which shaded off on the distant horizon to brilliant yellow and orange; but in mid-air, to the north-west, rode in the air a bank of clouds, over which the conical shadow was passing. Light was visible on both sides of the band of the total shadow, and all objects within that range and near the darkness seemed to come up quite close to one; distance seemed annihilated. I felt as if this bank of clouds was quite close upon me. It was composed of towering cloud masses, standing out in stereoscopic solidity, blotched (as a painting) with rounded masses of purple, blue-black, and grey, and at the edges having bands of burnt sienna; under the clouds was the bright light I have mentioned.”
Mr. John Goodall, M. Inst. C. E., observed the eclipse at Tahoraite, in the Forty-mile Bush. The following extracts are taken from his paper:—
“I went to Tahoraite on the afternoon of the 8th; the weather was not promising; there were repeated showers of rain, hail, and sleet up to two o'clock in the morning, ever, with any great hopes of being able to use it. By 6 a.m. but by five o'clock there was a fine clear frost, and scarcely a cloud in the sky, with every prospect of successful observations of the eclipse. I mounted my telescope, a 4 ½-inch refractor, and attached a direct vision spectroscope to it—not, how-all was ready, and the telescope pointed to the eastern horizon, which was perfectly clear. Towards the south there was a
heavy bank of clouds rising, looking dangerous enough to mar the event of the day. A stray cloud creeps near to the path of the sun, becomes illuminated, changing colour rapidly, ending with the silver lining, and the sun appears above the dark, ragged line of the tops of the distant New Zealand bush, perfectly clear of clouds; as it rises, three bands of clouds cross its face. This ominous indication soon disappears, and the sun is in its full splendour, revealing to the telescope two large groups of sun spots and faculæ in its eastern and western limbs. A peculiar ruddy tint now appears over the sun, caused probably by cosmic dust or earth vapour. As the sun rises to about 10° this ruddy tint disappears, and we patiently await the first contact of the moon, the first indication of which is a roughening of the sun's edge, and an appearance of dark pellets on the rim at contact. This is soon obscured by the sharp edge of the moon, the circular dent of which, in the sun's face, becomes clear, and the eclipse has fairly started. Gradually the moon creeps in along the path of the sun spots, the march of which becomes obliterated; and when it has obscured the sun by about one-fourth, the visible edge of the moon is tinged with an orange-yellow tint. This extends to about two minutes of space, and was observable until the sun was more than three-quarters obscured. The changing shape of the sun, as it was gradually obscured by the moon, was particularly interesting; and as it acquired the crescent shape, light began to diminish, and the atmosphere got very cold. The horns of the crescent sun were strongly tinged with deep orange; and when the crescent became very fine, it appeared to me at one time that a portion of it was obscured before the time, which must have been caused by an irregularity in the moon's edge. The eventful moment approaches: there is just a thin strip of the sun now visible, which scintillates like the stars, and the light is like that from the electric arc, of a bluish tint, and all shadows are sharp; there is a weird appearance over everything.…Suddenly the shape of the moon begins to show beyond the visible edge on the sun, and soon the whole of the moon is visible—a blacker circle in a black background. Instantly the corona appears as an encircling light, opposite to where the sun yet shines, fully ten seconds before totality; when of a sudden, as if the moon, gradually toiling on, made one last effort, it took one great leap and obliterated the sun, as if for ever; it was, indeed, awe-inspiring, and it is impossible to describe the feeling of the moment. Immediately the sun disappeared, there was a beautiful transformation scene. It appeared as if the sun's place was occupied by a beautiful black jet ornament, set with scarlet points, and fringed with strings of pearls.…Twenty minutes after the total eclipse, the sun was obscured by clouds.”
Mr. Meeson says, concerning the temperature:—“To get the variations in temperature during the continuation of the eclipse, I made use of two self-registering thermometers, which I inspected every quarter of an hour. One of these was fixed in its usual place, 6 feet above the ground, well in the shade, and protected from the wind; the other hung on the outside of a conservatory, 2 feet above the ground, and fully exposed to the sun. The following table gives the successive changes which took place:—
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|Time||¼ to 7 a.m.||7||7.15′||7.30′||7.45′||8||8.15′||8.30′|
“From this table it will be seen that my thermometers did not register such a great fall in the temperature as some observers report. In the shade there was a fall of four degrees, sufficient to carry the indicator below freezing point; and in the thermometer exposed to the sun, which more readily responded to the thermal changes, the fall was a clear six degrees. The coldest point of time seems to have been 8 o'clock, and not at the moment of totality—just as the coldest time during night is not at midnight, but two or three hours after, and the hottest part of the day not at noon, but about 2 p.m. If the early morning of 9th September had not been somewhat colder than usual—as a matter of fact the temperature then descended to 28°F.—perhaps the fall during the eclipse would have been more perceptible than it actually was; there was certainly a sudden fall at the moment of totality, for, though it was a minute of much excitement, everybody became sensible of the difference of temperature. The descent, however, recorded by the sunshine thermometer was, as we should have expected, greater and more sudden than that recorded by the instrument in the shade. I am quite prepared to believe that the actual fall during and immediately after totality was, as some observers say, even greater than that which I have recorded; but I find, in confirmation of my figures, that in Wellington the fall recorded was 5½°, and that the loss of temperature there was not recovered till nearly 9 a.m.”
The Bishop of Nelson states that the thermometer stood at 38° immediately before sunrise, and that during the eclipse it went down to 31°, the whole ground being covered with hoarfrost immediately after totality. The reduction of temperature was very evident, as also the getting up of a strong south cold wind.
The temperatures observed by Mr. T. W. Kirk, in Wellington, on behalf of the Government Observatory, are embodied
in the accompanying diagram, showing the curves of dry and wet bulb standards, recorded at every five minutes' interval from 6.30 to 8.45 o'clock.
Mr. Meeson's paper contains the following remarks:—“As to the so-called red protuberances, I saw distinctly prominences, but they, one and all, seemed to me intensely white or pearly in colour—such as those described by Professor Airy in the eclipse of 1851—rather than red.
“Perhaps my sense of colour was temporarily impaired by the unwonted and unearthly hues which prevailed on everything at the time. I could persuade myself, perhaps, that one or two of the smaller prominences, situated on the eastward of D. in the chart, were of a faint rose-colour, but not red. Whatever their colour, and whatever their real nature—mountains, clouds, or flames—they were exceedingly beautiful and wonderful; but, as they can be, and are now, studied at any time when the sun can be seen, whether he be eclipsed or not—or rather, perhaps, as the sun can be by modern astronomical contrivances so artificially eclipsed that the prominences are rendered visible—it is very improbable that any observations of ours as to them can have any scientific value. The differences in our impressions as to the relative size and place of the prominences, arise probably from the fact that our observations were not made precisely at the same second of time. At the commencement of totality the largest prominences visible were those on the lower eastern or right limb; and towards the close they were those on the upper western, or left limb. During the passage of the moon across the sun's face, the prominences near where the sun was last visible diminished in size, while those directly opposite considerably increased. In astronomical books these prominences
are said to be heaps, jets, or flames. Those which we saw were heaps, I think, and they were less serrated and fantastic in shape than some of us perhaps expected. Decidedly the largest prominences, towards the close of the total obscuration, appeared over the moon's left upper limb, at an angle of about 30° from the perpendicular, directly below the point where I observed the longest and most vivid coronal ray. Its apparent height above the limb of the moon could not have been less than 70,000 miles, for it reached to nearly 1½th of the moon's apparent or angular diameter, which I take to have been about the same as that of the sun—
Say 2½'—the sun's being 32′ 36.41″, or 850,000 miles in actual diameter,
the moon's 31′ 26″ " 2,153 " " "
How much this protuberance, or, indeed, any of the others, was foreshortened, of course it is impossible to say. The real height was perhaps in every case considerably above the apparent.
“Of two prominences I wish specially to speak. They do not seem to have been generally observed, but were clearly seen by other members of my household beside myself. One of them was also observed from the Hospital, by Dr. Boor. They were like tiny clouds, of a heapy character, and differed entirely from the other prominences, inasmuch as they were of a dun, or dark-smoke, nearly black colour. Their positions were, one at an angle of about 40° from the perpendicular towards the east, and the other at about 10° below the horizontal line on the lower western limb. Their position and relative size were recorded at the moment of observation. They were entirely different in appearance from the silvery or white, or rose-coloured prominences; and were no optical illusion, for I was so surprised to see them that I looked at them again and again with the binocular or coloured glass, and with the naked eye alternately. While I observed them, they seemed to undergo no change. What were they? Gold-schmidt noticed similar little grey clouds in the eclipse of 1860, (Proctor's “Sun,” p. 262,) but these were in part isolated, and floated, so to speak, outside the solar limb at some distance, and were also observed subsequently to develope into rose-coloured protuberances. Perhaps ours did the same, but the transformation was not observed by me. Someone says, ‘Were they planets?’ No; their size and irregularity of shape, apart from other reasons, would prevent us from entertaining that supposition. Were they faculæ projecting above the sun's disc, such as that seen by Mr. Dawes? (Proctor's “Sun,” p. 180.) Were they such dark curves as Herr Grosch, of the Santiago Observatory, saw upon the moon's limb, in the total eclipse of 1867; sharp curves, resembling in appearance lines drawn with lead-pencil on white paper? (Proctor's “Sun,” p. 346.) Were they mountains in the moon? If they were, lunar heights tower far higher than even those fabulous ones of Captain Lawson in New Guinea.
Professor Balfour Stewart, in one of the Manchester Science Lectures, says that the prominences sometimes assume the appearance of a cloud, instead of a fire or a fiery tree. If so, there need be no further difficulty. Our two little dusky patches have a place among recognized phenomena.”
The Bishop of Nelson says:—“The intensification of brightness at certain points in the above mentioned ring of light (see General Description above), the chromosphere or ring, amounted to luminous protuberances, which to my eye, and I can only answer for that, had the appearance of molten mountains of liquid silver, increasing with every beating second in intensity of whiteness, combined with the idea also of light or luminousness. Light seemed to flow out of them in liquid streams. It was condensed, not dispersed light; to speak in popular language, it seemed as if it were light coming out in liquid streams: lava streams of silver, ever and anon coming out of the three craters of light. I saw no red flames, though, honestly, I tried to see them; I had one momentary glance of redness, but that was at an earlier stage.…It seemed to me as if I witnessed once more what I witnessed in the north of England, at Bolton, in Lancashire, in the pouring out of the cauldron of molten steel in the Bessemer process, in which I believe oxygen plays so important and striking a part.”
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Mr. A. S. Atkinson states as follows:—“The only ‘red prominences’ I saw were a row of six or seven small ones, extending from about the vertical point towards the east, looking to the naked eye of about the same size and shape, and at about the same distance apart. Larger ones were seen by others, and, I believe, appear in three places in the photographs. The tallest of these red prominences, measured very roughly on the photograph, seems to be about 1/12th the diameter of the sun: if really so, it would represent a height of some 70,000 miles, while the long white cone I have mentioned (see Corona) was probably not less than 500,000 miles. Mr. J. R. Akersten obtained for me two small photographs during totality: one immediately after it began, with an exposure of something less than a second, the other a few seconds later with about double the exposure. A third plate was in the camera, and all but ready, when the sun reappeared; it was taken just after the reappearance, but two of the red prominences are still shown. It will also be noticed that in this photograph there is a rather well-marked ray, tangential to the reappearing sun, though not to the central point of the bright limb; or, say, not parallel to the line joining the two cusps; indeed, the latter line, if produced to the westward, would almost meet the ray as it is, without the latter being produced at all. There are also two short divergent rays of ordinary sunlight. There are also two short divergent rays from the eastern cusp, and a shorter and fainter one from the western
The tangential ray, measured from end to end through the glare, is apparently equal to two diameters; the longest of the shorter ones to little more than a quarter of a diameter. They are, I presume, rays of ordinary sunlight. If I might hazard a guess as to the cause of those from the cusps, I would ask whether they might not be owing to the irregularities of the moon's limb at those points, similar rays elsewhere along the limb being lost in the glare? It will also be seen that there is apparently a well marked halo round the emerging sun, which shows very strongly in the unenlarged original views. Whether this is merely the work of the camera, or is connected with the ‘sun-cloud’ now always surrounding the sun, or what else the cause may be, I am quite unable to say. I certainly did not see any such halo, but then I was closely watching the sun myself.” (For a very similar halo in a photograph of the full moon, see “Nature,” vol. xxi., p. 33.)
Mr. Goodall says: “While I was sketching, a flame seemed to burst out of the side of the moon in the opposite direction to where the sun was last observed, remain unaltered for a few seconds, then the corona gradually faded, and a flood of light was shed all round, and the grandest sight I ever witnessed came to an end. The scarlet setting, or the prominences, were very plainly visible through the telescope.”
Dr. Hudson states: “Of prominences I saw two, marked a, and I thought I saw a flat low one in the position marked v. I did not see the prominence marked c, which, as it has been so universally observed, must have been a distinct and real one. The prominences appeared like burnished silver, with a slight coppery tinge.”
With regard to this phenomenon, Mr. Meeson writes:—
“The general outline of the corona, towards the latter part of the period of totality, was, as it appeared to me, pretty much as represented in the accompanying chart, though there must have been other leading features which I had not time to observe. Generally its shape was irregular, and there was little or no four-cornered appearance. If there was any symmetry at all, it was as regards the place of the longest streamers (x and y), which were exactly on opposite sides, and at those parts of the sun's rim which were respectively the first and last to disappear behind the moon. Some of these streamers, particularly those from the upper western limb, and at an angle of about 30° from the perpendicular, could not have been less in length than 1½ times the moon's or sun's apparent diameter, i.e., not less than 1,275,000 miles. The greatest effulgence of light was in the neighbourhood of the longest
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streamers, and particularly round about the highest part of the upper limb. The least was in the lower western and upper eastern limbs—in the former of which the breadth was not more than ¼th of the moon's diameter, and in the latter, certainly as small as 1/12th, if not smaller. Although, for the most part, the streamers seemed to radiate as from a common centre—that is, the centre of the sun or moon—yet this was not universally the case; for some (particularly the ray marked z) seemed to proceed as from another centre, and interlaced with the more normal gleams. If these observations of mine—which have been compared and checked with similar notes and sketches made by other members of my family, whom I instructed beforehand, as well as I could, what to look for, and how to record—do not tally exactly with any bonâ fide photographic pictures of the eclipse which have been obtained in Nelson, two things must be remembered: One is, that the photograph is apt to give only the inner corona—the sierra, or leucosphere, as it is called—which is comparatively well-marked, and of stronger light; while the outer corona, or chromatosphere—perhaps on account of its more delicate light, or because there is inadequate exposure, or for some other reason—is very likely to be not at all represented. The other point to be remembered is, that the corona, or at all events the outer corona, varied in appearance at different periods of time during totality, for the rays visibly increased in length and altered in shape during observation. I read in Proctor's ‘Sun’ (page 314) that ‘the sharpness of outline in photographs of the corona is due to peculiarities in the process of development, special care being needed to prevent over-development of the negative.’ The corona in our eclipse was certainly not very sharply defined, for it was very difficult to say where the faint coronal tints ended and the abnormal hues of the sky began. If, as well as meteoric bodies and the sun's atmosphere, electric action plays a part in the formation of the golden glory which we are discussing, it might perhaps be expected that the appearance of that wonderful light would vary from moment to moment, even as in the case of the Aurora. Upon the whole, the picture which I present seems to agree pretty well with what others, with whom I have compared notes, observed. I noticed no rotatory motion of the beams, such as, I believe, has been sometimes previously observed, nor any flickering or quivering, except as before stated, just before and after totality. Proctor says of the eclipse of 1724, observed in France, that at the beginning of totality Maraldi perceived ‘that the corona was wider on the side towards which the moon was advancing than on the opposite side, but that at the close of totality the case was reversed.’ This exactly describes what I saw. The most vivid and brightest parts of the corona and the greatest prominences were decidedly
where the moon first touched the sun at the commencement of the eclipse, and at the point directly opposite thereto—that is, where the moon first emerged from before the sun's face. Proctor's generalisation, again, as to the relative development of the outer and inner corona, was certainly confirmed on this occasion. He says:—
“‘1. Where any great gap or rift appears in the outer or radiated part of the corona, there a depression is seen in the inner and brighter portion.
“‘2. Where the inner portion of the corona is depressed, there the coloured prominences are wanting, and the sierra is very shallow.’
“I think, if you will consider this carefully, you will agree with me, that what we saw confirms the generalisations here given. The colour of the corona, I should say, was that of very brilliant electric light, with, however, a faint but decided tinge of gold.”
The Bishop of Nelson gives the following account of the corona, as seen by him:—
“No sooner had the luminous body of the moon established itself on the eyes, and the luminous ring or chromosphere with its protuberances—which seemed to my eye to be at points corresponding to 4 or 5 o'clock, 2 o'clock, and 11 o'clock on the face of the sun, treated as an imaginary clock face—there came the next grand spectacle, almost instantaneously, yet with a slight deliberation (worthy as of regal stateliness), with nothing of the scenic or startling transformation slide or scene about it: from the luni-solar disc as a centre, and from the chromosphere, shot forth the glory of the corona from all points—well-likened to a Brunswick star, and, if I may be pardoned for such a matter of fact association and illustration, reminding me of some of those feats of armour decoration which may be seen in the corridor of the White Tower of London, where stars of every order are formed of rays made up of the sheen of bayonets or ramrods, polished and burnished almost as white as snow. There was a tendency to a square shape impressed on the whole, with the exception of what was about the line of the moon's equator, the bright rays extending to quite a distance of 1 ¾ times the sun's diameter on that side, and not nearly so much on the opposite side.…On some occasions of total eclipses this corona has been said to be too bright to be gazed at by the unshaded eye, but it was scarcely so on this occasion; one could look at it without pain. It seemed to have a somewhat vibratory movement, coruscations of light playing on the rays of the luminous stars. I saw through the binocular glass certain faint leaf-like bands of light, but too faint and too momentary to make any
record of them. I also saw, before totality, bright rays crossing like St. Andrew's cross.”
Dr. James Hudson remarks, with regard to the corona: “I can only speak certainly of the long projection, which I estimated at the time to extend three-fourths of the moon's diameter from the surface of the disc. This long projection appeared to me to be bifurcated at its extremity.”
V.—The Bands or Rats of Light, immediately before and
Mr. Meeson says, “This was a wonderful and unexpected phenomenon. While sun-gazing, perhaps a minute or two before totality, one of my party called out, ‘Look! look at the waves of light behind us!’ I turned, and was surprised to see a most beautiful effect, how produced, I cannot tell. It was as if streamers of light shot out from the quarter of the heavens where the eclipse was taking place, like the slender spokes of an enormous wheel of light, neither the nave nor the tire of which could be seen. All the time, too, the ‘wheel’ seemed to be rotating towards the west. The bands, as they stretched and quivered across the Waimea Plains, far as the eye could see, appeared to be about six or nine inches broad, and about the same space apart. Their direction was undoubtedly from north-east to south-west, and their colour was that of ordinary sunlight, only considerably subdued. During totality they disappeared, but on the sun's reappearance they were again visible, and riveted attention. Surely, thought I, the old fable is right, after all. There is a chariot of the sun! Phœbus, the son of Latona, guides it, and these bands are the light from his glorious wheels, as he drives majestically through the heavens. Yet, why visible now, and now only? And how is it that they do not seem to have attracted attention before now, when eclipses have occurred? You all saw what I am referring to. What were those quivering, mysterious, illimitable rays? Were they atmospheric, meteoric, spectroscopic, lunar, or coronal in origin?
“I could almost fancy that they were in the direction of the strongest coronal light, and might be produced by the coronal rays, which, before now, have been said to actually rotate. (Proctor's ‘Sun,’ p. 338.) The coincidence in point of time of the appearance of the two things is worth noting, as is also the coincidence of disappearance. But then it must be remembered that during totality, when the corona was most vivid, the bands of light were either absent altogether or exceedingly faint; at least that is my impression, though I cannot be positive about the fact, for at the time of total eclipse, my whole attention was
absorbed by the passing moon, and the coruscations of light about its limbs. Unfortunately man has not, like insects, compound eyes, enabling him to see at the same time both what is behind and what is before. If the ordinary beams of the corona did not produce the bands of light, did the exceptional quivering rays, which appeared just before and after totality, above and below the sun, and referred to early in this paper, do so? Or were the prominences or protuberances the cause of these mysterious bands? I mean, was their appearance in some way spectro-scopic, as well as spectral?
“We must remember that, for spectroscopic effect, we had virtually an isolated and thin pencil of light from the sun, and possibly from the prominences only, immediately before and after totality, and, furthermore, that the sun - prominence spectrum consists of bright lines; and perhaps something in-vening between the sun and the earth—atmosphere, meteoric bodies, vapour—operated as a prism to produce refraction (just as rain does to produce the rainbow), or as a fine grating to produce diffraction. I think that the dark colour between the bands of light was the same as the general colour of things at the time; in other words, not that the bands of light were alternated with dark bands, but that they were simply light bands on a dark surface. Otherwise, the dark bands might suggest the innumerable dark lines of the spectrum, rendered visible in some mysterious way by the exceptional circumstances, with intervening bands only approximately and relatively light, but really of various colours, or in some way divested of colour. But then the dark lines of the spectrum, though innumerable, are very irregularly disposed; whereas the dark lines which we saw, if they were dark lines at all, were very evenly and regularly distributed, and alternated invariably with light bands, and the light and dark seemed to be exactly of the same breadth. My knowledge of the spectrum and its laws is very small, too small to permit of my doing more than suggest questions, which perhaps may very easily be disposed of.
“If these suppositions be unentertainable, was the phenomenon atmospheric in origin? Evaporation in the hot sunshine can often, as is well known, be seen most distinctly, the moisture, as it ascends from the ground, being rendered clearly visible by its quivering motion to the height of several feet. It can also be seen in long and strong streaks through a mass of distant clouds in certain conditions of weather. There was a rapid change of temperature about the time of totality, but it was towards a lower point, not towards a higher, and the lost degrees were not recovered till nearly half-past eight o'clock, as has been already explained. The quivering motion of evaporation occurs during exceptional heat, when the ground is, through recent rains, moist. The circumstances do not seem to be at all
parallel, nor, indeed, are the phenomena, for the matter of that; for our bands of light were broad, well-marked, and, I think, only slightly quivering, very different from the tiny, tremulous, hair-like threads of moisture seen during extensive evaporation. If these bands, then, were atmospheric in origin, how were they produced?
“I read (Proctor's, ‘Sun,’ p. 362) that General Meyer saw, from White Top Mountain, in Virginia, during the total eclipse of 1860, something similar, except that the bands were of various colours, and do not seem to have moved. He says: ‘It was as if bands of broad ribbon of every conceivable hue had been stretched in parallel lines half round the universe.’
“If there had been such a thing as a lunar atmosphere, it might have been conceivable that the bands were in some way owing to the pencil of rays from the sun, just before and after totality, passing through that atmosphere on its way to the earth. But we are assured that there is no atmosphere worth speaking of in the moon; if one exist at all, it is of exceeding rarity. However, even a very thin, ethereal atmosphere, particularly if in the places where the rays intersected it, full of foreign matter of any kind, liquid, solid, or gaseous, would possibly occasion the spectral appearance, of the cause or causes of which we are in doubt.
“It has been seriously suggested by some of our members, that the bands perhaps represent successive jerks forward, made by the moon in its passage across the sun! Now, we must be well aware that there can scarcely be anything of the nature of a jerk or leap in the orbital motions of the heavenly bodies, as the forces producing those motions are steady, continuous, ever-pressing, eternal. Is it possible, however, that we can apply the atomic theory to motion, as well as matter? Of course, the movement of the heavenly bodies, inconceivably rapid as it is, is, at our distance (except in the case of meteors, shooting-stars, etc.) imperceptible, unless we look for a difference of position at consecutive points of time. But so is the movement of a man or a horse at a considerable distance, when going really at a very quick pace; as we approach nearer, however, we see that the movement which, further off, appeared so easy, even, and regular, really consists of a series of jerks forward. Just as, too, in the case of a railway train. If we had power of vision quick and keen enough to analyse the easy motion along the lines, we should see, I imagine, that it consisted of a series of jerks, each of which would represent the result of a contest between the power of steam and the resistance of friction. Now, apply this kind of reasoning to the motion of a celestial body, a star or planet, in its orbit. We know that, in accordance with the parallelogram of forces, that motion is in the direction of a diagonal between two lines, the one of which represents in length
and direction the centrifugal force, the other the centripetal. How, however, does the heavenly body comply with these forces, or, rather, acquire the direction of their resultant, except by a series of steps, so to speak, down or up a ladder—i.e., by alternately giving way to one force and then to the other, each movement representing an atom of time as well as an atom of space? Granted that the atom of motion thus conceived of had real existence, the effect in light and shade, considering the magnifying effect of the great distance, might be possibly such bands of light as those we saw on the morning of the 9th September.
“This, however, you must understand, is only an attempt—and a bad one—to put another's crude suggestion into something like philosophical form. My own opinion is that the bands of light, in some way, were produced by the coronal rays, perhaps aided by something exceptional intervening in the space between them and the surface of the earth. But then, the non-appearance of the bands during totality seems a difficulty. I shall be very curious to hear what interpretation the astronomers in the old world put upon this phenomenon: and, by the way, I have not noticed that the observers in Wellington District observed it at all, though I can scarcely believe but that they did. If it were confined to the Nelson Provincial District, that surely would be a strong argument for thinking that the bands were simply produced by some local and temporary peculiarity in our atmosphere.
“Just one personal word in conclusion. I make no pretension whatever to astronomical knowledge or acumen. Carlyle is quoted as having said somewhere: ‘Why did not somebody teach me the constellations, and make me at home in the starry heavens, which are always overhead, and which I don't half know to this day?’ That was my feeling the other morning. With a hand trained for telescopic and other instrumental work, and an eye trained for the observation of heavenly objects, and a mind stored with astronomical principles and facts, the chance we have just had of observing and recording wonderful, rare, and mysterious phenomena was one which could have been used to grand advantage. Such a chance will probably never again fall to the lot of any of us.”
The Bishop of Nelson states in his paper: “I am told by those at Collingwood that on the snow-covered hills above the Aorere there were broad belts of colour of all shades, and that the lighthouse and the Spit looked from Collingwood as if they were close at hand, within walking distance.”
Mr. Atkinson writes: “As the sun was just disappearing, the most striking phenomenon I witnessed, looking straight at it, was a strongly-marked ‘pulsation’ in its light; those who were looking away from it saw waves of shadow passing rather rapidly along the ground, just after as well as just before totality. This,
also, I supposed was from the unsteadiness of the air; but to me it seemed certainly not the least striking part of the great spectacle to see the sun flickering, as it were, before it went down.”
Dr. J. Hudson says on this subject: “About five minutes before totality I was standing with my back to the sun, looking on the ground in front of me, when I saw fine films floating over the surface of the ground. I rubbed my eyes, thinking there must be water in them, and looked again; there were the films plainer than before. Soon they began to take more definite shape, and appeared as long bands of light and shade, moving rapidly across the field of vision from E.S.E. to W.N.W. I thought for a moment, were they the shadows of clouds of mist? I looked up, but the whole atmosphere was perfectly clear, besides there was no wind; I held up my hand to feel, and it was then what I should call a dead calm. However, there were the long lines of light and shadow travelling rapidly in a westerly direction, and more and more distinct did they appear until the moment of totality, when they completely disappeared, to reappear again when totality was over. I cannot say what direction they travelled in after totality.”
Mr. A. Coleman, in his “Observations on the Solar Eclipse,” says:—
“The phenomenon which most struck me, and to which I believe I paid the most attention, was the peculiar vibratory shadows which passed across the earth's surface during the eclipse. Scientific observers have no doubt recorded and fully accounted for this striking phenomenon, but never having read of such, nor having seen any explanation for them, I venture to offer one, which, however, may neither be original nor correct. A curious property of light, discovered by Grimaldi in 1665, later on independently by Newton, but more thoroughly investigated by Fremel, was that termed the inflection or diffraction of light. When a divergent ray of light admitted into an apartment was just intercepted by an opaque spherical body of a suitable size and at a suitable distance, surrounding the shadow cast upon a screen were seen concentric rays of coloured light, ‘the fringes’ of Grimaldi, whilst in the shadow itself were to be seen alternate light and dark bands of light.
“In investigating this latter phenomenon, Dr. Young saw that they were capable of a satisfactory explanation upon his admirable and comprehensive undulatory theory. To use his own words, ‘the fringes within the shadow were produced by the interference of the rays bent into the shadow by one side of the body (intercepting) by the rays bent into the shadow by the other side.’
“In the present instance the moon's disc formed the obstructing body, causing the light and dark bands in its
shadow on the earth's surface, and their flickering movements were due to the moon's movement altering continuously the distance of the undulations from either side of the moon, and with them the positions of the shadows.”
Observing at Tahoraite, Mr. A. McKay, of the Geological Department, remarked the flickering of different shades of light at the surface of the ground, and on looking up obliquely towards the sun, saw most distinctly undulating vibrations in the air like those produced by ascending currents. From his position he had a favourable opportunity of observing during totality the return of the light in the rear of the shadow on the Ruahine Ranges, 6,000 feet in altitude, and about 6 miles to the westward, and he distinctly saw the light advancing as banded streamers.
Note.—The Ven. Archdeacon Stock has called the Editor's attention to the following extract from the London Athenæum, August 2nd, 1851, p. 821, which evidently points to a similar phenomenon having been observed on the occasion of a previous total eclipse:—
“Great Solar Eclipse.—In observing the solar eclipse here yesterday, during the intervals that the showery and cloudy state of the weather permitted, I noted the following fact, which I am not aware has been before observed, and which may be interesting as in a great degree explanatory of some of the most remarkable phenomena attending total eclipses. The rays passing close to and over the moon's body were much agitated. This I at first was inclined to ascribe to the vapoury state of the atmosphere, but soon noticed that could not have been the cause, as the light from the sun's external limits was calm, and gave a most distinct marginal line, while that portion of the sun's face which was bounded by the convex and dark outline of the satellite and that outline seemed to be dancing together. In case of any mistake, I caused two friends successively to examine the appearance, and they both reported it to be distinctly such as described. The instrument used was a Newtonian reflector, of 6 inches diameter, with a magnifying power on of about 180.—I am, &c.—P. McFarlane.—Comrie, Perthshire, July 29, 1851.”
Explanation of Plates XIV.–XVI.
|Fig. 1.||Combined from several.||Eye sketch, Wellington (Petone).|
|2.||Mr. Gell||Photograph print, Wellington.|
|3.||Mr. Holmes||" " "|
|4.||"||" " "|
|5.||"||" " "|
|6.||Mr. Parsons||Telescopic sketch (high power), Wellington.|
|7.||Mr. Higginson||" "(low power),"|
|8.||Mr. W. B. Hudson||" "" Karori.|
|9.||Mr. T. W. Kirk||Eye sketch, Wellington.|
|12.||Mr. Goodbehere||Photograph print, Taonui.|
|13.||Mr. Goodal||Eye sketch, Tahoraite.|
|14.||Mr. Harding||" Danevirke.|
|15.||Mr. McKay||" "|
|17.||Mr. Seymour||Telescopic sketch, Picton.|
|18.||Mr. Tyree||Photograph print, Nelson.|
|19.||Bishop of Nelson||Eye sketch, Nelson.|
|20.||Mr. Meeson||" "|
|21.||Mr. Innes Jones||" "|