486 

of the North of England, is engaged in founding at Newcastle- 
upon-Tyne, 
The Executive Committee fully recognises the importance of 
Biology. The professorial chair, which was called at the public 
meeting that of Geology and Mineralogy, will be called, according 
to a subsequent decision of the committee, the Chair of Geology, 
Biology, and Mineralogy. It is true that this designation leaves 
it uncertain whether Biology is co-ordinated with Geology, and 
has its claim to be a distinct science allowed, or is subordinated 
and intended to be treated only as a component part of Geology. 
In the former case, it may be said, the Chair will be too capacious 
for one man to fill; in the latter, the rights of biology are but 
inadequately acknowledged. 
The answer to this is, that the programme of teaching is 
necessarily, at the present stage of affairs, initiatory. It will, 
no doubt, when the work of the Institution has commenced, and 
the scale of operations which everything seems to foreshadow has 
been in some measure realised, receive such expansions and 
modifications as are suitable to the relative value of the sciences, 
and the actual wants of the students. J. WAITE 
University College, Durham, April 17 
The Aurora Borealis 
A VERY bright display of aurora was visible here last night, 
illuminating the greater part of the heavens at intervals with a 
fitful light. At oh. 45m., when I first noticed it, broad cirrus-like 
brushes of white light stretched in parallel bands across the 
zenith, from below Corona in the north-east, across Cor Caroli, 
nearly overhead, to about the altitude, and 15° or 20° south of 
Venus, then shining dimly through clouds in the western sky. 
My view of the aurora was afterwards confined to an east win- 
dow ; but froma short examination of a clear part of the sky 
towards south-west, it appeared to be almost as bright, at 
first, in the opposite direction as in the quarter between north 
and east, where I had, from that time onwards, an uninter- 
rupted view of its progress. The streamers were white, 
and irregular in form, rising from no distinct arch, or definite 
base in any quarter, but they occasionally met and formed 
a bright corona overhead. A rose-tint pervaded some of 
them, in the north-east, at toh. 30m., and presented itself in dif- 
ferent parts of the sky until about 11h., when the phenomenon 
faded, and a faint glow only remained visible in the north. At 
about 11h. 40m., while streamers reappeared, forming a bright 
corona overhead, whose arcs and beams appeared to grow more 
densely luminous until 12h. 15m. It then showed a well-defined 
central nucleus, with rays of great brightness proceeding from it, 
about three-sevenths of the distance from 7 Ursee Majoris to 
Arcturus, white streamers rising to meet it all round, with the 
appearance of a cupola ordome. While I watched some of the 
brighter stars through its dense light-cloud, it rapidly assumed a 
vivid fiery red colour, and a similar bright appearance breaking 
out at the same moment at the base of a north-east streamer, the 
fiery glow reflected among the clouds in that direction perfectly 
resembled a distant conflagration. A wide expanse of brilliant 
orange and crimson-red light soon joined these two regions, of 
greatest intensity together in one splendid blaze of ruddy colours. 
This brilliant outburst faded away at 12h. 25m., the streamers 
disappearing, until 12h. 40m., when they again met overhead, 
and formed a corona with a sharply-defined nucleus, about 3° 
west of the star y Bootis. The light of the white streamers 
flickered considerably, as if waves of varying brightness were 
driven rapidly over the whole phenomenon by the wind. Until 
after two o'clock, when the moon rose, and their light was 
weakened although not extinguished, a constant succession of 
bright steamers occupied the north-east sky between the horizon 
and the zenith ; towards these I directed the slit of a Browning’s 
Student’s Spectroscope, in order to determine, if possible, the 
position of some of the auroral lines. A single greenish line 
only was so faintly visible in the spectroscope that all attempts 
to view it simultaneously with the cross-wires of the instrument 
proved unsuccessful. A simple form of pointer, substituted for 
the use of the wires in the dark field of the telescope enabled 
me, however, to identify its position with considerable accuracy. 
A circular card, of the figure shown in the sketch, was slipped 
into the forward end of the eye-piece until it reached the dia- 
phragm upon which the cross wires are stretched. It was so 
disposed that the angular pointer in the middle of the card 
exactly filled up the lower angle of the cross-wires ; andits sharp 
NATURE 



[April 20, 1871 . 

point coincides almost exactly with the place of their intersection. 
In a field of view almost dark it was possible to see the summit 
of the card-pointer with considerable distinctness; and if a 
great and imposing phenomenon may be compared with an 
object so diminutive, the appearance of its dark peak, sur- 
mounted by the narrow, flickering line: of light, resembled in 
the dim field of view the cone of a volcano, projecting in a thin 

jet from its apex frequent eruptions of varying height and bright- 
ness. By obtaining a reading of the soda-line seen in the flame ofa 
salted spirit lamp, and referred to the pointer in the same manner, 
I obtained as a result of three observations of theauroral line, differ- 
ing less than two minutes on the graduated position-circle of the 
spectroscope, a place in the spectrum twenty-four minutes more 
refrangible than Fraunhofer’s line D. Many observations of the 
dark lines of the solar spectrum, compared with their positions in 
Kirchhoff’s maps, having assured me that a minute of arc on this 
spectroscope corresponds between Fraunhofer’s lines D and 4, 
with 10°44 divisions of Kirchhoff’s scale, the resulting difference 
of refrangibility between the green auroral line and Fraunhofer’s 
line D is 250°6 divisions of Kirchhoff’s scale ; and its absolute 
position, assuming for that of D to be 1005 Kirchhoff, was within 
IO or 20 units on either side of a place at about Kirchhoff 1255. 
A bright line in the spectrum of the aurora was observed by M. 
O. Struve at Pulkowa, in April 1868, whose position he ascer- 
tained to be within 10 or 15 units of the scale at Kirchhoff 
1259, a place apparently identical with that of the bright line 
which was principally visible in last night’s aurora. The faint 
and uncertain brightness of its appearance, while confining my 
attention principally to its observation, prevented me from search- 
ing in other parts of the spectrum for accompanying bright lines 
Within a space of about 400 Kirchhoff on each side of that 
which was recorded, I could, however, perceive no traces of any 
co-existing lines. The position of the bright lines which are 
most conspicuous in different auroras is, perhaps, a subject of 
interesting inquiry in connection with the yet unascertained laws 
which govern their appearance, and with the varying characters 
and peculiarities of their phases. A remarkable circumstance 
connected with the appearance of the single line observed on 
this occasion, was the flickering and frequent changes with which 
it rose and fell in brightness, apparently even more rapidly than 
the swiftly travelling waves, or pulsations of light, that repeatedly 
passed over the streamers, near the northern horizon, towards 
which the spectroscope was directed. 
A. S, HERSCHEL 
Andersonian University, Glasgow, April 10 
THERE was a brilliant display of aurora borealis visible from 
this place on Sunday the gth inst. I first noticed it about 
10.45 P.M.; there was then aconsiderable luminosity in the N. W. 
with a magnificent red glow and streamers springing from the 
W. extending to within 20° of the eastern horizon, also radiation 
from other parts in the N. and N.W., but less brilliant. At 
about 10.55 P.M., a bright streamer made its appearance near 
the zenith crossing the red at right angles, and standing out 
clearly upon it. The aurora had nearly faded away at II. 10. 
When it was at its brightest through a direct-vision spectroscope 
with the slit rather wide and directed tothe N. W., where there was 
scarcely any colour, the red and green bands usually seen under 
such circumstances were clearly defined, more particularly the 
red band. I then directed the spectroscope to the W., at a part 
where the red light was most intense, to my surprise the red band 
was scarcely to be discerned, and looked blurred, and spread out 
