482 
NATURE 
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| April 24, 18 
of cirrostratus cloud, had considerable resemblance to auroral 
beams faintly visible in the twilight ; a considerable extension of 
the twilight-glow towards the north- west also suggested the very 
possible character of their light. Towards nine o'clock Mars 
rose redly through a considerable haze in the east, and Venus, 
in full splendour, appeared setting among slight clouds in the 
west ; the planet Jupiter, and all stars above a slight distance 
from the horizon, were altogether unobscured by clouds. A 
pretty bright white auroral arch, divided into low streamers, was 
at this time first distinctly formed, its lower edge being well 
marked by their bases, and the brightest streamers being clus- 
tered in two knots of the arch, in the middle of Cassiopeia, and 
of Lyra, the first immediately under Polaris, and the other close 
to the north-east horizon ; the western prolongation of the arch 
was faint and diffuse, shining from behind and among the clouds 
around the planet Venus. ‘Tall but faint streamers rose from it, 
none of which were conspicuous, excepting a pretty well defined 
one rising at gh 5™ from the strongly luminous light-cloud in 
Lyra, nearly to the tail-stars of Ursa Major. This beam 
grew sharper, and in the following minute it passed across 
o Herculis, and e« Urs Majoris, but it shortly disappeared. 
Between gh 8™ and 9! 12™ the two principal light-clouds in Cas- 
siopeia and Lyra increased in strength, assuming with the con- 
tiguous part of the arch a perfect resemblance to the heavy 
fringe of a curtain gathered or folded upon itself at those points, 
and particularly in the group of streamers under a Lyra. At g? 
12™ another luminous patch marked the western end of the arch 
between Venus and Capella, growing brighter, and from it a 
bunch of rose-coloured streamers sprang upwards between Auriga 
and Geminias far as the forefoot of Ursa Major. At 9215™, the 
bright cloud-mass marking the eastern horizon-point of the arch 
under a Lyrz also acquired great strength, throwing up a 
torch-like, fire-coloured streamer of moderate height “and 
great brightness, terminating the arch abruptly in that direc- 
tion. It rose from the horizon across o, x to 7, p, Herculis. 
A fainter arch underneath the former one was visible at this | 
time, but less well-defined, and streamers rising from both 
arches, and mingling together, soon quite overspread the 
northern sky; a bunch of these streamers of rich crimson 
colour appeared at 92 18™, extending for a short time across 
o, 8, and other neighbouring stars of Ursa Major, and fading 
gradually away, disappeared almost as quickly as it came. The 
number and sharpness as well as the height of the streamers 
rising from both the arches were now very great, and the light 
from all the surrounding streamers was so strong that I could 
read my watch and correct notes in my note-book at this time. 
A fourth bunch of red streamers rose from the arch at its 
extreme west end at 95 23™ from the neighbourhood of a Orionis 
to the stars y, v, in the feet of Gemini. This was the last 
strikingly red streamer seen during the display ; its spectrum, 
like that of the white beams, which I examined with a small 
pocket spectroscope, appeared to consist only of the usual 
bright greenish line, which was very vivid in every phase of the | 
aurora. 
At gh 25™, the whole northern half of the sky was covered 
with streamers, and arches, gradually forming a corona over- | 
head, and increasing rapidly to great intensity and brightness. 
The boundary of the light from east to west was a definite line 
passing through, or very little south of the corona, whose centre | 
was 3° or 4° east from the. stars vy, x in Ursa Major. North- | 
wards from the boundary line the aurora consisted of six or | 
seven parallel arches (of which only the lowest two had _ before 
been visible), more or less distinctly succeeding each other | 
be'ween the zenith and the horizon. Both the arches and 
streamers were stationary, and presented no sensible tendency to 
motion, however slow, while they were visible. At this time the 
brightening streamers began to flicker in their light. Waves 
of light, rising from the north, succeeded each other rapidly, 
and appeared to flow swiftly over them towards the zenith. 
Arch after arch was visible as the waves passed over them, and 
fitful gleams among the auroral masses overhead shot to and fro 
there, like flashes of summer lightning. The rays and wisps of 
the corona, and bel's, or fagments of the aurora overhead 
were rendered especially luminous by these discharges. Farther | 
from the zenith, in the north, the waves rose smoothly and / 
steadily, with a m tion that was indeed very swilt, but it wis 
yet quite distinc ly discerni le, and more easily distinguishable 
there, than in their passage overhead. The arches, or belts of 
the stream rs appeared to he lighted up instantaneous!y, as they 
were reached, Although their inter-mixture in the north made | 
it very difficult to decide this clearly, yet the upward progress 
of the waves there was very evident, while no such ascending 
movements could be distinguished in the east and west quarters 
of the sky. The belts and arches stretching towards those parts 
of the horizon, through the zenith, and past, or through the 
corona, forming the termination of the aurora towards the south, 
were constantiy lighted up by momentary flashes, extending 
almost simultaneously along their whole lengths. The brightness 
of the flashes in those parts of the aurora which included the 
corona, and arches or lateral branches extending from it towards 
the magnetic east and west points is easily accounted for by the 
belts and clusters of streamers in those positions being seen ‘*on 
edge,” or ‘‘end on,” extremely foreshortened by perspective, so 
that the increase of light along their whole heights appeared to 
be concentrated, when the waves overtook them, to a single 
flash. The motion of the waves must be extremely swift, as 
they scarcely occupied more than a second in passing from an 
altitude of about 45° to the zenith. Supposing that (as the best 
observations of them have frequently agreed in showing) the 
heights of auroral arches, and of the bases of auroral streamers, 
are usually about 100 miles above the earth’s surface, the velocity 
of propagation of these waves of electrical disturbance from 
north to south cannot have been much less than 100 miles per 
second. Such a prodigious velocity cannot possibly be ascribed 
to waves in the upper atmosphere driven by winds among its 
rarified strata, to which the sweeping motion of the light waves ~ 
apparently wafted by gusts among the streamers otherwise bore a 
very singular resemblance. 
At 98 34™ some of the strongest waves passing across the 
corona lighted up a faint white arch in the south, extending 
from Arcturus across the northern part of Virgo to the head of 
Leo, several degrees in width. At 9237™, when the wave 
disturbance, after continuing in full activity for about ten 
munutes, ceased as rapidly as it began, this arch and the corona 
still remained faintly visible; but together with all the other 
arches and streamers of any altitude lately lighted up by the 
waves, they soon vanished, and the whole appearance of the 
sky at gh 40™ was about the same as when the aurora was first 
seen, At gh 43™, however, the northern sky was again 
crowded in every part with thin white streamers scattered in- 
discriminately over it, like groves of slender fir-trees on a hill- 
side, among which one very sharp and bright ray shone for a 
few seconds, springing from the horizon to a considerable alti- 
tude in the west, where it passed across ¢ Tauri. At 9! 
50™ a streamer, starting from a base of intense whiteness near 
the same place, and tinged at the top with a pinkish hue, as- 
cended across the stars mw, v, as far as the star « in Gemini, 
another very similar streamer almost simultaneous with it, also 
extended from between Gemini and Auriga to near the forefoot or 
Ursa Major ; afew spots of very intense white light were at the 
same time visible here and there among the low clouds near the 
north-west horizon. At 9 55™ all conspicuous streamers 
had disappeared, leaving only a general glow, among the 
brighter parts of which the wave disturbance began again, and 
with less intensity than before, but with the same regularly as- 
cending motions ; the undulations succeeded each other without 
intermission until rob 5™; they then ceased, and the famt 
| appearances of the aurora which were visible after this time 
were, so far as I could observe them, until half-past eleven 
o’clock, of a very insignificant and inconspicuous character. 
The times in this description are from a comparison of my 
watch with the clock in the Carlisle railway station, and its 
hand and the figures on its dial being always distinctly visible 
by the light of the aurora, they have probably been recorded 
rightly 10 the nearest mnute. Altnough the dates of the April 
meteoric shower usually occurring on the nights of the 19th 
—21st of April are near at hand, I saw but one small shooting- 
star during the hour of the auroral exhipvition. It had a short 
course in one of the brightest parts of an auroral cloud, and in 
its light and the aspect of its nucleus it did not appear to be 
affected in any way remarkably by its passage near or under- 
neath the beams of the aurora. A, S. HERSCHEL 
Carlisle, April 18 ene 
April Meteors 
DuRING the evenings of April 19 (94 to 114) and 2oth (8 
45™ to 114 15™) 20 shooting “stars were observed here. The 
sky was cloudless on both nights, and on the 18ta and rgth 
bright displays «f aurorze were noticed. Of the 20 meteors 12 
were well obseryed, and their tracks accurately marked ; 8 of 
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