The description, from my notes made at the time of this fine display, is as follows:—“Last evening (October 24) the Aurora Borealis was again most beautifully seen here (Guildford). At 6 P.M. indications of the coming display were visible in the shape of a bright silver glow in the north, which contrasted strongly with the opposite dark horizon. For two hours this continued, with the addition from time to time of a crimson glow in the north-east, and of streamers of opaque-white phosphorescent cloud, shaped like horse-tails (very different from the more common transparent auroral diverging streams of light), which floated upwards and across the sky from east and west to the zenith. At about 8 o’clock the display culminated; and few observers, I should think, ever saw a more lovely sky-picture. Two patches of intense crimson light about this time massed themselves on the north-east and north-west horizon, the sky between having a bright silver glow. The crimson masses became more attenuated as they mounted upwards; and from them there suddenly ran up bars or streamers of crimson and gold light, which, as they rose, curved towards each other in the north, and, ultimately meeting, formed a glorious arch of coloured light, having at its apex an oval white luminous corona or cloud of similar character to the phosphorescent clouds previously described, but brighter. At this time the spectator appeared to be looking at the one side of a cage composed of glowing red and gold bars, which extended from the distant parts of the horizon to a point over his head. Shortly after this the Auroral display gradually faded away, and at 9 o’clock the sky was of its usual appearance, except that the ordinary tint seemed to have more of indigo, probably by contrast with the marvellous colours which had so lately shone upon it.”
T. F., describing the same Aurora from Torquay, says it showed itself at sundown, attained its maximum at 8, and lasted until 11. At 8 o’clock more than half the visible heavens was one sea of colour; the general ground greenish yellow and pale rose, with extensive shoals of deep rose in the east and west; while from the north, streaming upwards to and beyond the zenith, were tongues and brushes of rosy red, so deep that the sky between looked black. Mr. Gibbs reported that in London, at about 8 o’clock, brilliant crimson rays shot up to the zenith, and the sky seemed one mass of fire.
A facsimile of my water-colour sketch of this fine discharge is given on Plate III.
Plate III.
Mr. Barker’s (superposed) red and white Auroræ, 9th November (1870?).
On the 9th November (1870?) Mr. Barker saw at New Haven (U. S.) a most magnificent crimson Aurora. At about a quarter to 6 P.M. it consisted of a brilliant streamer shooting up from the north-western horizon. This was continued in a brilliant red, but rather nebulous, mass of light passing upwards and to the north. Its highest points were from 30° to 40° in altitude. A white Aurora, consisting of bright streamers, appeared simultaneously and extended round to the north-east. Prof. Newton informed Mr. Barker that he had observed an equally brilliant red patch of auroral light in the north-east five or ten minutes earlier.
Since the lower end of the red streamers was much lower than that of the white, it would seem as if the red were seen through the white, the red being most remote.
Spectroscopic observations of this Aurora were made. The crimson Aurora lasted less than half an hour, and then disappeared. In the white Aurora, which remained, the crimson line could not be seen.
It may be here noted that during the Aurora seen by Carl Bock in Lapland, and painted by him by its own light (described, p. 25), he had the impression of sets of vibrating rays behind each other, and in the drawing it looks as if streamers were seen behind an arc.
Plate IV.
Mr. J. R. Capron’s Aurora of February 4th, 1872.
My description of this Aurora as seen at Guildford, and as given at the time, is as follows:—“Last evening, returning from church a little before 8 P.M., the sky presented a weird and unusual aspect, which at once struck the eye. A lurid tinge upon the clouds which hung around suggested the reflection of a distant fire; while scattered among these, torn and broken masses of vapour, having a white and phosphorescent appearance, and quickly changing their forms, reminded me of a similar appearance preceding the great Aurora of 24th October, 1870. Shortly some of these shining white clouds or vapours partly arranged themselves in columns from east to west, and at the same time appeared the characteristic patches of rose-coloured light which are often seen in an auroral display. About 8 o’clock the clouds had to a certain extent broken away, and the Aurora shone out from behind heavy banks of vapour, which still rested on the eastern horizon, the north-west horizon being free from cloud and glowing brightly with red light. And now, at about 8.15, was presented a most beautiful phenomenon. While looking upwards, I saw a corona or stellar-shaped mass of white light form in the clear blue sky immediately above my head[4], not by small clouds or rays collecting, but more in the way that a cloud suddenly forms by condensation in the clear sky on a mountain top, or a crystal shoots in a transparent liquid, having too, as I thought, an almost traceable nucleus or centre, from which spear-like rays projected. From this corona in a few seconds shot forth diverging streamers of golden light, which descended to and mingled with the rosy patches of the Aurora hanging about the horizon. The spaces of sky between the streamers were of a deep purple (probably an effect of contrast). The display of the corona, though lasting a few minutes only, was equal to, if not excelling in beauty, the grand display of October 1870, before described, in which case, however, a ring or disk of white light of considerable size took the place of the stellar-shaped corona. What struck me particularly was the corona developing itself as from a centre in the clear sky, and the diverging streamers apparently shooting downwards, whereas in general the streamers are seen to shoot up from the horizon and converge overhead. The effect may have been an illusion; but, if so, it was a remarkable one. The general Aurora lasted for some time, till it was lost in a clouded sky; and, in fact, rain was descending at one time while the Aurora was quite bright. Strong wind prevailed during the night[5]. The Aurora was probably very extensive, as the evening, notwithstanding the clouds, was nearly as bright as moonlight. The peculiar clouds referred to must have preceded the Aurora in daylight, as I recollect seeing them at 6.30 as we went to church.”
They had even then a peculiarly wild, ragged, and phosphorescent appearance, and so much resembled some I had seen to accompany the Aurora of October 1870, that I predicted (as came to pass) a display later in the evening. A facsimile of my water-colour sketch of this Aurora is given on Plate IV. fig. 1, while the corona and rays are represented (with rather too hard an outline) on Plate V. fig. 2.
Description of an Aurora seen at Cardiff.
An Aurora was seen at Cardiff. A dusky red aspect of the sky towards the north, and extending itself across the zenith westward, made its appearance about half-past 5 P.M. The lights reached their greatest intensity at 6 o’clock, when the sky was suffused with a rich crimson glow, a broad band of colour reaching from N.E. to W. A corona of deep hue, having rugged sharply defined edges, stood out prominently in the zenith, apparently on a parallel plane to the earth, and having its centre almost immediately over the head of the spectator.
From this corona, elliptic in form, and in its broadest diameter about four times the size of the moon, there were thrown out brilliant silvery blue radii, extending to the N.E. and W. horizon, and presenting the appearance of a vast cupola of fire.
At half-past 6 the lights died completely out, leaving masses of cloud drifting up from the south, and a shower of rain fell. The corona was remarked upon as unusual. At Edinburgh the sky was brilliant for several hours. (The date of this Aurora is uncertain, as the account is from an undated newspaper cutting. It is supposed to be in February 1872, but could hardly have been on the 4th, as the Aurora of that date did not reach its maximum development at Edinburgh till 8 P.M.)
Mr. J. R. Capron’s Aurora, seen at Guildown, Guildford, February 4th, 1874.
About 7 P.M. my attention was drawn to a silvery brightness in the north-east. Above, and still more to the east, was a bright cloud of light, which looked dense and misty, and gave one the impression of an illuminated fog-cloud. The edges were so bright that the adjacent sky, but for the stars shining in it, might, by contrast, have been taken for a dark storm-cloud. The light-cloud expanded upwards until its apex became conical, and then moved rapidly from east, along the northern horizon, until it reached the due west, where it rested, and formed for some time a luminous spot in the sky. About the same time a long low arch of light formed along the northern horizon, having a brighter patch at each extremity; and these being higher in the sky, the arch and turned-up ends were in shape like a Tartar bow. This bow was permanent; and later on a cloud of rose-coloured light formed in the east, looking like the reflection of a distant fire. From the bow also shot up curved streamers of silver light towards the zenith, which at one time threatened to form a corona. This, however, did not happen, and the Aurora gradually faded away, until, when the moon rose about 8, a silver tinge in the east alone remained. I should also mention that fleecy horizontal clouds of misty light floated in the north above the bow across the streamers.
Mr. H. Taylor informed me he saw a similar Aurora some three weeks before, in which the bright horizontal light and short white streamers were the main characters. I am not sure that the horizontal light-clouds were not actual mist-clouds illuminated by reflection of the Aurora; not so, however, I think, the first-mentioned cloud, which had more the appearance of the aura in the large end of an illuminated Geissler tube.
I examined the Aurora with a Browning direct-vision spectroscope, and found Ångström’s line quite bright, and by the side of it three faint and misty bands towards the blue end of the spectrum upon a faintly illuminated ground. I could also see at times a bright line beyond the bands towards the violet. There was not light enough to take any measurements of position of the lines.
I made a pencil sketch of this Aurora, at the time when the light-cloud had moved W. and the arc formed, and of the spectrum. These drawings are reproduced on Plate VI. figs. 1 and 1a.
Plate VI.
Mr. Herbert Ingall’s Aurora, July 18th, 1874.
An Aurora of July 18th, 1874, seen by Mr. Herbert Ingall at Champion Hill, S.E., was described by him as an extraordinary one. About 11 the sky was clear; at midnight the sky was covered by a sort of haze canopy, sometimes quite obscuring the stars, and then suddenly fading away. Mr. Ingall was shortly after remarking the sky in the S.E. and S. horizon as being more luminous than usual, when his attention was drawn to a growing brightness in the S.W., and a moment afterwards bright bluish flames “swept over the S.W. and W. horizon, as if before a high wind. They were not streamers, but bright blue flames.” They lasted about a minute and faded; but about two minutes afterwards a glowing luminosity appeared in the W.S.W., and broke into brilliant beams and streamers. The extreme rays made an angle of 90° with each other, the central ray reaching an altitude of 50°. The extreme divergence of the streamers (indicating their height above the earth’s surface), and their direction (from W.S.W. to E.N.E.) at right angles to the magnetic meridian, suggested to Mr. Ingall a disturbance of an abnormal character. The rays had an oscillatory motion for about fifteen seconds, and then disappeared, “as if a shutter had suddenly obscured the source of light.”
Mr. Ingall’s remarks were corroborated by an observer in lat. 54° 46´ 6″·2 N., long. 6h 12m 19s·75 W. The display, however, was more brilliant, and the intensity of light at midnight illuminated the whole district as with an electric light. The rays, too, bore tints differing from one another; the largest seemed to partake of the nature of the blue sky, while the smaller ones, running parallel with the horizon, were ever changing from blue to orange-red.
On June 25 (same year?), between 9 and 10 o’clock, the Rev. Chas. Gape saw at Rushall Vicarage, Scole, Norfolk, in the E.S.E., very frequent flashes or streaks of a pale blue colour darting from the earth towards the heavens like an Aurora. The day had been dull and close, with distant thunder. In the E.S.E. it was dark, but overhead and everywhere else it was clear and starry.
Mr. J. R. Capron’s White Aurora of September 11th, 1874.
On September 11, 1874, we were at Kyle Akin, in the Isle of Skye. The day had been wet and stormy, but towards evening the wind fell and the sky became clear. About 10 P.M. my attention was called to a beautiful Auroral display.
No crimson or rose tint was to be seen, but a long low-lying arc of the purest white light was formed in the north, and continued to shine with more or less brilliancy for some time. The arc appeared to be a double one, by the presence of a dark band running longitudinally through it.
Occasional streamers of equally pure white light ran upwards from either end of the bow. The moon was only a day old, but the landscape was lighted up as if by the full moon; and the effect of Kyle Akin lighthouse, the numerous surrounding islands, and the still sea between was a true thing of beauty. The display itself formed a great contrast to the more brilliant but restless forms of Auroræ generally seen. I particularly noticed a somewhat misty and foggy look about the brilliant arc, giving it almost a solid appearance. The space of sky between the horizon and the lower edge of the arc was of a deep indigo colour, probably the effect of contrast. I had a strong impression that the bow was near to the earth, and was almost convinced that the eastern end and some fleecy clouds in which it was involved were between myself and the peaks of some distant mountains.
I have not seen any other account of this Aurora, of which I was able at the time to obtain a sketch. This is reproduced on Plate VII. It was a lovely sight, and wonderfully unlike the cloud-accompanied and crimson Auroræ which I had seen in the South.
It is noticed in Parry’s ‘Third Voyage’ that the lower edge of the auroral arch is generally well defined and unbroken, and the sky beneath it so exactly like a dark cloud (to him often of a brownish colour), that nothing could convince to the contrary, if the stars, shining through with undiminished lustre, did not discover the deception.
I saw no trace of brown colour. The segment below the arch resting on the horizon was of a deep indigo colour.
Plate VII.
Dr. Allnatt’s Aurora, June 9th, 1876.
Dr. Allnatt, writing to the ‘Times’ from Abergele, North Wales, near the coast of the Irish Channel, reported an Aurora on the night of the 9th June, 1876. After a cool and gusty day, with a strong N.E. wind and a disturbed sea, there appeared at 11 P.M. in the N. horizon a broad band of vivid auroral light, homogeneous, motionless, and without streamers. About midnight a long attenuated streak of black cirro-stratus stretched parallel with the horizon, and divided the Aurora into nearly symmetrical sections. On the preceding day the sky was covered with dark masses of electric cloud of weird and fantastic forms. The season had been singularly unproductive of high electric manifestations, which Dr. Allnatt thought might be attributable to the comparative absence of spots on the solar disk. [It may here be noted how conspicuous the years 1877 and 1878 have been for absence of Sun-spots and of Auroræ.]
Plate VIII.
Herr Carl Bock’s Lapland Aurora, 3rd October, 1877.
In January 1878 I had the pleasure to meet, at the Westminster Aquarium, Herr Carl Bock, the Norwegian naturalist, who accompanied four Laplanders, two men and two women, with sledges, tents, &c., on their visit to this country. The Laplanders (as mentioned elsewhere) did not confirm the accounts of noises said to have been observed by Greenlanders and others during the Aurora. Carl Bock mentioned to me that the displays he saw in Lapland were most brilliant, but generally of the yellow type (the Laplanders called the Aurora “yellow lights”). He saw only one red Aurora. He kindly lent me a picture (probably in its way unique), an oil-painting of an Aurora Borealis, entirely sketched by the light of the Aurora itself.
The painting is remarkable for the tender green of the sky, an effect probably due to a mixture of the ordinary sky colour with the yellow light of the Aurora. This picture was taken at Porsanger Fjord, in lat. 71° 50´, on 3rd October, 1877. It lasted from 9 P.M. till about 11 P.M. The rays kept continually moving, and certain of them seemed in perspective and behind the others. It will be noticed that the inner edge of the arc is fringed with rays, contrary to the sharp and definite margin which is usually presented. Probably two Auroræ or auroral forms were seen—a quiescent arc in front, and a set of moving streamers beyond. Two larger and brighter patches of light are seen at each extremity of the arc, as in the case of the Aurora seen by me at Guildown, February 4th, 1874, which, indeed, the display much resembles. A reduced facsimile of Herr Bock’s excellent picture is given on Plate VIII.
Herr Bock also acquainted me that on the following day he saw an Aurora in which the lines of light, instead of being vertical, were longitudinal, and were continually swept along in several currents. They were not so strong as in the former case.
Rev. T. W. Webb’s Aurora.
The Rev. T. W. Webb has described to me in a letter an Aurora very like that seen by Carl Bock in Lapland, and apparently the prevailing type in those regions. An arc similar to that figured by Carl Bock appeared in the N.W., and seemed to resolve itself into two sets of streamers moving in opposite directions (or the one set might be fixed and the other moving), like the edges of two great revolving toothed wheels. This lasted but for a few seconds; but during that interval the tints were varied and brilliant, including blue and green.
The English Arctic Expedition 1875-76, under Capt. Sir George Nares.
In anticipation of the starting of this Expedition, some instructions for the use of the officers in connexion with the hoped for display of brilliant Auroræ were prepared:—as to general features of the Auroræ, by Professor Stokes; as to Polarization, by Dr. William Spottiswoode; and as to Spectrum work, by Mr. Norman Lockyer and myself. As these instructions were somewhat elaborate, and will apply to all Auroral displays, I have supplied a copy of them in Appendix B. They were unfortunately not brought into requisition, for want of the Auroræ themselves. Capt. Sir George Nares has reported to the Admiralty, under date 5th December, 1877, as follows:—“Although the auroral glow was observed on several occasions between 25 October, 1875, and 26 February, 1876, true Auroræ were seldom observed; and the displays were so faint, and lasted so short a time, and the spectrum observations led to such poor results, that no special report has been considered necessary. Although the citron-line was observed occasionally, on only two displays of the Aurora was it well defined, and then for so short a time that no measure could be obtained.” (For Sir George Nares’s further Report see Appendix C, containing extracts from blue-book, ‘Results derived from the Arctic Expedition, 1875-6.’)
Aurora Australis.
In an article on Auroræ in high Southern latitudes (Phil. Trans. No. 461, and vol. liv. No. 53), we find that Mr. Forster, who as naturalist accompanied Capt. Cook on his second voyage round the world, says:—“On February 17th, 1773, in south latitude 58°, a beautiful phenomenon was observed during the preceding night, which appeared again this, and several following nights. It consisted of long columns of a clear white light shooting up from the horizon to the eastward almost to the zenith, and gradually spreading over the whole southern part of the sky. These columns were sometimes bent sideways at their upper extremities; and though in most respects similar to the northern lights of our hemisphere, yet differed from them in being always of a whitish colour, whereas ours assume various tints, especially those of a fiery and purple hue. The sky was generally clear when they appeared, and the air sharp and cold, the thermometer standing at the freezing point.” This account agrees very closely in particulars with Capt. Maclear’s notice of Aurora Australis [after referred to], and especially in the marked absence of red Auroræ.
The height of the barometer does not appear to be mentioned, the temperature being apparently much the same as in the more recent cases.
In a letter dated from H.M.S. ‘Challenger,’ North Atlantic, April 10th, 1876, Capt. Maclear was good enough to communicate to me some particulars of an Aurora Australis seen 3rd March 1874, in lat. 54° S., long. 108° E. The letter is mainly descriptive of the spectrum (which will be described in connexion with the general question of the spectrum of the Aurora). It states that the red line was looked for in vain, and that the light appeared of a pale yellow, and had none of the rosy tint seen in the northern displays.
Capt. Maclear has since contributed to ‘Nature,’ of 1st November 1877, a description of four Auroræ seen from the ‘Challenger’ in high southern latitudes (including the one communicated to me). He speaks of the opportunity of observing as not frequent, either from the rarity of the phenomena, or because the dense masses of cloud prevalent in those regions prevented their being seen except when exceptionally bright. There were four appearances described:—
(1.) At 1.30 on the morning of February 9th, 1874, preceded by a watery sunset, lat. 57° S. and long. 75° E., bar. 29·0 in., ther. 35°; brilliant streaks to the westward. Day broke afterwards with high cirrus clouds and clear horizon.
(2.) At 9.30 P.M., February 21, 1874, lat. 64° S., long. 89° E., bar. 28·8 in., ther. 31°; one bright curved streamer. The Aurora preceded a fine morning with cumulo-stratus clouds, extending from Jupiter (which appeared to be near the focus) through Orion and almost as far beyond. Under this a black cloud, with stars visible through it. Real cumuli hid great part of the remainder of the sky, but there were two vertical flashing rays which moved slowly to the right (west). Generally the Aurora was still bright.
(3.) At midnight, March 3rd, 1874, lat. 53° 30´ S., long. 109° E., bar. 29·1, ther. 36°, after some days’ stormy weather, a brilliant sunset, followed by a fine morning. Soon after 8 P.M. the sky began to clear and the moon shone out. Noticing the light to the southward to be particularly bright, Capt. Maclear applied the spectroscope, and found the distinguishing auroral line.
About midnight the sky was almost clear, but south were two or three brilliant light clouds, colour very white-yellow, shape cumulo-stratus. From about west to near south extended a long feathery light of the same colour, parallel with the horizon, and between south and west there appeared occasionally brilliant small clouds. The upper edges seemed hairy, and gave one the idea of a bright light behind a cloud. The forms changed, but no particular order was noticed.
(Here follows a description of the spectrum, and the mode in which a delineation by the lines was obtained.)
(4.) At 8 P.M., March 6th, 1874. This was a slight Aurora, seen to the southward; after this the clouds changed to high cirrus. Capt. Maclear suggests whether a low barometer has any thing to do with the absence of red in the spectrum, the normal state of the barometer being an inch lower in those regions than in more temperate latitudes.
Edin. Encyc. vol. iii. article “Aurora.” Dr. Kirwan observed that the barometer commonly falls after the Aurora. Mr. Winn, in the seventy-third volume of the Phil. Trans., makes the same remark, and says that in twenty-three instances, without fail, a strong gale from the south or south-west followed the appearance of an Aurora. If the Aurora were bright, the gale came on within twenty-four hours, but was of no long continuance; if the light was faint and dull, the gale was less violent, longer in coming, and longer in duration.
The pale yellow-coloured glow referred to by Capt. Maclear is, in my experience, rare in the Aurora Borealis. It is probably the “æqualiter et sine eruptionibus aut radiis fulvi,” described by Seneca (antè, p. 1), and may probably belong to more southern climes.
We shall see too, by-and-by, that these Auroræ Australes as to spectrum extend more into the violet than the Aurora Borealis. The yellow, as complementary to violet, is likely thus to make (in the absence of the red) its appearance.
It is, however, somewhat singular that Carl Bock found almost exclusively yellow Auroræ in Lapland.
In Proctor’s ‘Borderland of Science,’ article “The Antarctic Regions,” we find quoted a passage from a letter by Capt. Howes, of the ‘Southern Cross,’ in which a graphic description is given of a Southern Aurora:—
“At about half-past one on the 2nd of last September the rare phenomenon of the Aurora Australis manifested itself in a most magnificent manner. Our ship was off Cape Horn, in a violent gale, plunging furiously into a heavy sea, flooding her decks, and sometimes burying her whole bows beneath the waves. The heavens were as black as death, not a star was to be seen, when the brilliant spectacle first appeared.
“I cannot describe the awful grandeur of the scene; the heavens gradually changed from murky blackness till they became like vivid fire, reflecting a lurid glowing brilliancy over every thing. The ocean appeared like a sea of vermilion lashed into fury by the storm, the waves dashing furiously over our side, ever and anon rushed to leeward in crimson torrents. Our whole ship—sails, spars, and all—seemed to partake of the same ruddy hues. They were as if lighted up by some terrible conflagration. Taking all together—the howling, shrieking storm, the noble ship plunging fearlessly beneath the crimson-crested ways, the furious squalls of hail, snow, and sleet, drifting over the vessel, and falling to leeward in ruddy showers, the mysterious balls of electric fire resting on our mast-heads, yard-arms, &c., and, above all, the awful sublimity of the heavens, through which coruscations of auroral light would shoot in spiral streaks, and with meteoric brilliancy,—there was presented a scene of grandeur surpassing the wildest dreams of fancy.”
The foregoing picture presents a singular contrast to the yellow-white Auroræ described as seen in high southern latitudes by Capt. Maclear, and is interesting as a southern Aurora of a red or ruddy tint. Looking, however, at the extreme rarity of red Auroræ in those latitudes, and the description of “mysterious balls of electric fire resting on our mast-heads, yard-arms, &c.” (a phenomenon not often noticed in connexion with the Aurora), it suggests itself that the case in question may have been an instance not of a true Aurora, but of an electric display, with conditions approaching those experienced by travellers who have found themselves in mountainous districts surrounded by storm-clouds charged with electricity[6].
Prof. Piazzi Smyth’s Typical Auroræ.
Prof. Piazzi Smyth was kind enough lately to send me the fourteenth volume of the ‘Astronomical Observations made at the Royal Observatory, Edinburgh, during the years 1870-1877.’ This volume, amongst its other interesting matter, affords some valuable information on the subject of the Aurora Borealis. The Aurora plates are five in number, three comprising some well-executed chromo-lithographs of typical Auroræ, from sketches made by Prof. Smyth, the other two plates being of the Aurora spectrum. The Auroræ delineated are thus described:—
Plate 5. (August 6, 1871.) An example of a mild quiescent kind of auroral arc, with dark cavernous substratum. (August 21, 1871.) An example of a bright large active arc darting out rays.
Plate 6. (September 7, 1871.) An auroral arc, with streamers and dark clouds, and maintaining a bright appearance though in proximity to the moon. (May 8, 1871.) A double-arched auroral arc (the arches are longitudinally arranged).
Plate 7. (April 28, 1871.) A multiple-arched arc of Aurora with moonlight. (October 25, 1870.) A case of grandest coloured Auroræ, or Aurora superb and almost universal.
All the foregoing drawings are very vivid and striking, and form a most interesting set of typical forms of Auroræ.
According to my own experience, the Aurora with arches arranged longitudinally, thus, , is the rarest of all the forms. I have not met with it myself, nor do I recollect an illustration of one other than Prof. Smyth’s.
CHAPTER IV.
PHENOMENA SIMULATING AURORÆ.
Auroric Lights (Kinahan).
Mr. G. Henry Kinahan writes to ‘Nature,’ from Ovoca, under date January 27th, 1877, and speaks of two distinct kinds of light so classed—one brilliant and transparent, of a white yellowish-blue or yellowish-red colour, while the other is semi-opaque and of a bloody red colour, the latter being considered in Ireland a forerunner of bad weather. The first kind generally appears as intermittent pencils of light that suddenly appear and disappear.
Usually they proceed or radiate from some point near the north of the horizon; but Mr. Kinahan has frequently seen them break from a point in the heavens, not stationary, but jumping about within certain limits. Sometimes these lights occur as suddenly flashing clouds of light of a white colour, but at other times of blue and reddish yellow.
If this class of lights is watched into daylight, they appear somewhat like faint rays of a rising sun. One morning, while travelling in West Galway in the twilight, they were very brilliant, and quite frightened Mr. Kinahan’s car-driver, who thought the sun was going to rise in the north instead of the east. The second, or bloody red light, usually occurs in clouds floating in one direction up into the heavens, but often diffused over a portion of the sky. Mr. Kinahan has never seen them coming from the east, and on only a few occasions from the south, but generally from the west, north-west, or north.
If both kinds of light appear at the same time, the second while passing over the first dims it. If the second class is watched into daylight, they appear as dirty misty clouds that suddenly form and disappear without the spectator being able to say where they come from or where they go to, or as a hazy mist over a portion of the sky, that suddenly appears and disappears, or as misty rays proceeding from a point in the horizon. Generally, when these clouds occur, there is a bank of black clouds to the westward.
Mr. Kinahan then speaks of the season as having been prolific in auroric light, as there had been few nights since the 1st October then last (1876) in which they did not appear. On many occasions they were late in the night, being very common and brilliant during the dark days of December, a few hours before dawn (about 5 o’clock). Each time there was a fine day they appeared also, and the weather broke again.
Mr. Jno. Allan Broun refers to this graphic account of Mr. Kinahan’s, and concludes there must have been some mistake as to the nature of these “auroric lights,” as the Aurora Borealis is very rarely seen at 5 A.M. in this country. In the years 1844 and 1845, during which the Aurora was sought for at Makerstown every hour of the night, it was observed in 77 nights on an average of nearly three hours each night; but it was seen only twice so early, and that with a bright or brilliant Aurora, which remained during five hours on the first occasion, and from 6 P.M. to 6 A.M. on the second. Parts of the phenomenon seen by Mr. Kinahan, Mr. Broun also could not say he had ever seen; and if Mr. Kinahan’s observations could have been confirmed it would have been most important, especially as made so frequently at the epoch of minimum. The description is in many respects a sufficiently recognizable one of auroral discharges; but the frequent appearance in early morning is certainly unusual, and few if any Auroræ seem to have been recorded as appearing elsewhere in Great Britain during the time which Mr. Kinahan refers to as so prolific (see, however, Dr. Allnatt’s, antè, p. 24). In fact, the season in question was one of marked infrequency (see English Arctic Expedition Report, antè, p. 26). Mr. Buchan furnished Mr. Broun with a note of Auroræ seen in the stations of the Scottish Meteorological Society during the year 1876, and they were 42 in number, 26 in the first half, and 16 in the second half of the year. The greater part were seen in the most northerly stations, including the Orkney, Shetland, and Faroe Islands, and only 9 south of the Forth.
Luminous Arch.
In the ‘Annals of Philosophy,’ vol. iv. p. 362, there is a minute description of a luminous arch which appeared in the sky on the night of Sunday, September 11th, 1814, and was seen in the west of England opposite the Irish Sea, the west part of the south of Scotland, and part of the west of Ireland. It was described as a part of either a body of dense greyish-white light, or a mass of luminous matter in the shape of an arch. Its height above the horizontal line was estimated at not more than 9 nor less than 6 miles.
Its direction when first seen was N. 80° E., and S. 80° W. It moved to the southward. It was assumed to differ from the Aurora Borealis in wanting coruscations, and in its having a much paler light.
CHAPTER V.
SOME QUALITIES OF THE AURORA.
Noises attending Auroræ.
In the Edinb. Encyc., Gmelin is stated, in continuation of his description of an Arctic Aurora, to add:—“For however fine the illumination may be, it is attended, as I have heard from the relation of many persons, with such a hissing, cracking, and rushing noise through the air, as if the largest fireworks were playing off.” To describe what they then heard, the natives are said to use the expression, “Spolochi chodjat”—that is, The raging host is passing. The hunter’s dogs, too, are also described as so much frightened when the Auroræ overtake the hunters, that they will not move, but lie obstinately on the ground till the noise has passed. This account of noises seems to be confirmed by other testimony. They are stated to have been heard at Hudson’s Bay and in Sweden; and Musschenbroek mentions that the Greenland whale-fishers assured him they had frequently heard the noise of the Aurora Borealis, but adds that “no person in Holland had ever experienced this phenomenon.” Mr. Cavallo declares he “has repeatedly heard a crackling sound proceeding from the Aurora Borealis” (Elements of Nat. or Exper. Phil. vol. iii. p. 449). Mr. Nairne mentions that in Northampton, when the northern lights were very bright, he is confident he perceived a hissing or whizzing sound. Mr. Belknap of Dover, New Hampshire, North America, testifies to a similar fact (American Trans. vol. ii. p. 196).