30 SEVENTH REPORT—1837. 
in some instances, over stars of the first magnitude, whose lustre was 
but little diminished by their light. 
On this occasion I noticed a phenomenon which I had some years 
before observed in a most striking form: namely, the dark Aurora 
cloud breaking through the light above it. Having, on the former 
occasion to which I have just alluded, omitted to note the month and 
year, at the time I noted the successive appearances of the Aurora, I 
cannot now refer to the date. I first observed the Aurora at 74 30, 
in the form ofa faint arch, about 25° in height, its middle point bear- 
ing nearly magnetic north. This arch continued for nearly two 
hours, becoming gradually brighter. It was succeeded by three 
arches, formed one within another, and having, 10° below them, a dark 
arch. These again were, in about an hour from their first appearance, 
succeeded by a single well-defined arch, in the same position, and 
having below it a remarkably well-defined dark arch. This shortly 
afterwards appeared to break through the luminous band, dark streams 
rushing upwards, and breaking up the arch in every part: these dark 
streams were almost immediately succeeded by brilliant coruscations. 
Subsequently, both the dark arch and luminous band were re-formed. 
Captain Back has since observed a similar phenomenon, in a still 
more striking form, while in his winter quarters at Fort Reliance. 
I have on other occasions, during the present summer, observed 
clear indications of Aurora, though not of a decided character; but 
these are sufficient to show that this phenomenon occurs at all seasons 
of the year, and to render it probable that it is principally the shorter 
duration of the nights from the vernal to the autumnal equinox which 
renders it less frequently visible during this period than in the winter 
half of the year. I have here only noticed the occurrence of the 
Aurora during the summer ; but all must be aware how frequently, 
and with what brilliancy, it has presented itself in the south of Eng- 
land during the last twelve months; indeed, I consider, that in no 
case has a period of a month elapsed without a striking exhibition of 
it. In the month of February there occurred one, the most extraor- 
dinary that, I believe, is on record in these latitudes. 
To what are we to attribute this frequent occurrence, during the 
present and a few previous years, of a phenomenon which had for a 
considerable time before been comparatively rare?* This is an im- 
portant question in meteorology, to which, in the present state of 
science, only conjecture can be offered in reply; and this must con- 
tinue to be the case, until the phenomenon itself, with all its attendant 
circumstances, shall have been more carefully observed than hitherto, 
My own avocations are of a nature to preclude me from making such 
observations ; but I entertain a confident hope, that there will not be 
wanting members of the British Association both willing and able to 
devote their time and attention to this highly interesting inquiry. 
* May 30, 1838. 1 may now remark that, as far as my own observation and any 
information I have obtained go, the Aurora Borealis has been of very rare occurrence, 
in the south of England, during the last winter and the present spring, particularly as 
compared with the preceding year. This is the more remarkable when taken in con- 
junction with the severity and long continuance of the cold weather,—S, H. C. 
