The Aurora. 
377 
1880.] 
variety of appearances which the Aurora may assume, that 
the different accounts differ greatly. One observer is struck 
by the steady pale gleam of the arch of light ; another by 
the ruddy streamers spread out fan-wise; a third by the 
drifting coruscations which seem to sweep at a prodigious 
rate across the sky. What wonder if the accounts are occa- 
sionally tinged with details derived unconsciously from the 
observer’s imagination, though set down in all sincerity as 
objective facts. Mr. Capron has impartially given all these 
marvellous details supplied by different observers ; and with- 
out pretending to sift their claims, or to reject, or criticise 
in any general manner, he lets each record stand upon its 
own merits. This method of treating the >ubject, while 
possessing many obvious advantages, has the one disadvan- 
tage of perplexing the reader, and compelling him to refer 
continually from the points in one set of observations to 
those in another. For many purposes the work would have 
been more valuable had something more been done towards 
guiding the reader towards a harmonious conception of the 
facts. But from the very nature of things this must be 
extremely difficult, and we should indeed be sorry to lose 
some of the precious details of isolated observations, which 
would run a risk of being shorn away in any such process 
of condensation. Isolated or exceptional facts, when really 
well established as facts, furnish indeed the most significant 
clues towards further phenomena : they are the finger-posts 
of scientific discovery. From amongst them we will select 
a few samples : — 
On the 3rd of October, 1877, Herr Carl Bock witnessed 
an Aurora in Lapland sufficiently brilliant to enable him to 
sketch it in oil colours. A reduced facsimile of this painting 
is given opposite p. 25 of Mr. Capron’s book. A significant 
point in Herr Bock’s observation was that the auroral arch 
appeared to consist of two Aurorae, one behind the other, a 
quiescent arc in front, and a set of moving streamers behind. 
Capt. McClintock makes the important observation that 
when Aurorae are present the atmosphere is never quite 
clear, there being usually a bank of low fog or cloud below 
the auroral streamers. 
Prof. Lemstrom, in 1868, when accompanying the Swedish 
Polar Expedition, observed an auroral streak to burst forth 
suddenly during a fall of snow. The same author made 
some remarkable observations on the appearance of luminous 
beams around the tops of mountains, which the spectroscope 
proved to be of the same nature as the true Aurora. 
Another precious and pregnant indication is to be found 
