AURORA BOREALIS. 
what different from those which are seen 
here. On February 17, 1773, in south la- 
titude 58°, “ a beautiful phenomenon (he 
says) was observed during the preceding 
night, which appeared again this and several 
following nights. It consisted of long co- 
lumns of a clear white light, shooting up 
from the horizon to the eastward, almost 
to the zenith, and gradually spreading on 
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 (au- 
rora borealis) of our hemisphere, yet dif- 
fered from them in being always of a whit- 
ish 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.’’ 
The periods of the appearance of these 
northern lights are very inconstant. In 
some years they occur very frequently, and 
in others they are more rare; and it has 
been observed that they are more common 
about the time of the equinoxes than at 
other seasons of the year. Dr. Halley (see 
Philos. Trans. No. 347, p. 406,) has col- 
lected together several observations, which 
forma kind of history of this phenomenon. 
After having particularly described the va- 
rious circumstances which attended that ob- 
served by himself and many others in 
March, 1716, and which was singularly 
brilliant, he proceeds with informing us, 
that the first account of similar phenomena 
recorded in the English annals, is that of 
the appearance which was noticed January 
30, 1560, and called “ burning spears,” by 
the author of a book intitled “ A Descrip- 
tion of Meteors,” by W. F. D. D. reprinted 
at London, in 1654. The next appearance 
of a like kind, recorded by Stow, occurred 
on October 7, 1564. In 1574, as Camden 
and Stow inform us, an aurora borealis was 
seen for two successive nights, viz. 14th and 
15th of November, with appearances simi- 
lar to those observed in 1716, and which 
are now commonly noticed. The same 
phenomenon was twice seen in Brabant, in 
1575, viz. on the 13th of February and the 
28th of September ; and the circumstances 
attending it were described by Cornelius 
Gemma, who compares them to spears, for- 
tified cities, and armies fighting in the air. 
In the year 1580, M. Mastline observed 
these phasmata, as he calls them, at Bak- 
liang, in the county of Wirtemberg, in Ger- 
many, no less than seven times in the'space 
of twelve months; and again at several 
different times, in 1581. On September 
2nd, 1621, the same phenomenon was seen 
Over all France; and it was particularly 
described by Gassendus, in his “ Physics,” 
who gave it the name of “ aurora borealis.” 
Another was seen all over Germany in 
November 1623, and was described by 
Kepler. Since that time, for more than 
eighty year’s, we have uo account of any 
such phenomenon, either at home or abroad. 
In 1707, Mr. Neve observed one of small 
continuance in Ireland; and in the same 
year, a similar appearance was seen by 
Romer, at Copenhagen ; and during an in- 
terval of eighteen months, in the years 1707 
and 1708, this sort of light had been seen 
no less than five times. Hence it should 
seem, says Dr. Halley, that the air, or 
earth, or both, are not at all times disposed 
to produce this phenomenon, though it is 
possible it may happen in the day time, in 
bright moon shine, or in cloudy weather, 
and so pass unobserved. Dr. Halley fur- 
ther observes, that the aurora borealis of 
1716, which he described, was visible from 
the west of Ireland to the confines of Russia, 
and to the east of Poland ; extending at 
least near 30° of longitude, and from about 
the 50th degree of north latitude, over al- 
most all the north of Europe ; and in ail 
places at the same time, it exhibited ap- 
pearances similar to those which he ob- 
served at London. He regrets, however, 
that lie was unable to determine its height 
for want of contemporary observations at 
different places. 
Father Boscovich has determined the 
height of an aurora borealis, observed on 
the 16th of December 1737, by the Mar- 
quis of Poleni, to have been 825 miles ; and 
Mr. Bergman, from a mean of thirty com- 
putations, makes the average height of the 
aurora borealis to be 72 Swedish, or (sup- 
posing a Swedish mile to be about 6| En- 
glish miles) 468 English miles. Euler sup- 
poses the height to be several thousands of 
miles; and Mairan also assigns to these 
phenomena a very elevated region, the far 
greater number of them being, according 
to him, about 200 leagues above the sur- 
face of the earth. Dr. Biagden, speaking 
of the height of some fiery meteors (Phil. 
Trans, vol. lxxiv. p. 227), says, that “ the 
aurora borealis appears to occupy as high, 
if not a higher region, above the surface of 
the earth, as may be judged from the very 
distant countries to which it has been visi- 
