OF A NORTH-WEST PASSAGE. 
307 
much more brilliant, its general position and character remaining, however, 1820. 
nearly as before. It still appeared chiefly to the southward of the zenith, 
the arch-like appearance continuing with increased splendour, and accom- 
panied for about a quarter of an hour by a beautifully waving light, of the 
rapidity and magnificence of which it is impossible to convey any adequate idea. 
The motion of this light reminded one of the contortions of a snake, except 
that its velocity was often so great that the eye could with difficulty follow 
it. The most intense part was of a pale greenish colour ; the rest nearly 
white. The arch, which before had been stationary, at one time shifted its 
position, by appearing, as it were, to turn up its legs so as to form a part of 
a circle seen in perspective in the south, parallel to the horizon. The lumi- 
nous patch, or cloud, in the E.N.E. increased also very much in brightness at 
the same time, emitting more vivid coruscations, but continuing, as before, quite 
distinct from the rest of the phenomenon. This Aurora, when brightest, gave 
nearly as much light as that of a full moon. There could not be the smallest 
doubt that it dimmed, and even sometimes altogether obscured, the stars over 
which it passed. We particularly remarked, that wherever there was a broad 
stream of its light stationary for some time in any part of the heavens, it pro- 
duced exactly the effect of a curtain ; for we could only distinguish stars of 
the first and second magnitudes through it, while those of inferior brilliancy 
were visible in great numbers by the side of it. In this, as in several pre- 
vious instances, the Aurora appeared very near us, though it was evidently 
higher than some clouds which were passing, as might readily be distin- 
guished by the latter intercepting a part of its light. The electrometer was tried 
during the most brilliant part of the phenomenon; but neither on this or on any 
other occasion, in crossing the Atlantic, did the gold leaf give any indication 
of electricity ; nor was the magnetic needle in the slightest degree affected. 
The arch-like appearance above described was not bisected by the magnetic 
meridian, but by the magnetic N.E. and $.W. At a quarter before eleven the 
light became less brilliant, and spread mflfe to the northward, and then gra- 
dually disappeared before midnight. 
On the 11th, being in lat. 61° IT, longitude 31° 12', some water brought Wed. ] 1. 
up from a depth of three hundred and twenty fathoms, in Dr. Marcet’s bottle, 
was at the temperature of 44°|;, the surface water being at 47°|, and the 
air 48°. 
At seven P.M., on the 13th, the wind being squally from the N.N.W., Frid. 13. 
the Aurora Borealis began to display itself in a bright luminous patch in 
2 R 2 
