314 
AURORAS. 
of the auroral displays, as compared with those of the 
Northern Atlantic, on the European side. I had the 
same feeling. 
Their changes seemed to be dependent upon modi- 
fications rather of intensity than form. They were 
characterized by neither active movement nor varied 
coloring. My tabular observations will be published 
elsewhere, but I subjoin a rude attempt at analysis of 
their distinctive features. 
1st. A mere illumination, apparently emerging from 
a dark cloud some five degrees above the horizon, 
more resembling a nebulous patch or a moonlight cir- 
rus than the auroral light. 
2d. Detached bands of illumination, impressed 
against the sky, like a condensed nebulosity, uncon- 
nected with any visible central arc, and distributed 
near about the line of the magnetic axis between the 
horizon and the zenith. These were sometimes strat- 
iform, converging by perspective, and reminding one 
of the auroral plates, plaques aurorales of Lottin. 
3d. A well-marked zone pr band, or sometimes sev- 
eral concentric ones, either broken or continuous, un- 
accompanied by the ordinary segments of light or 
cloud, passing through or near the zenith in a direc- 
tion which, according to the mean of some fourteen 
observations, was sixteen degrees east of the magnetic 
meridian. These bands were constantly varying, not 
by active scintillation, but by changes of intensity — 
rapid flashing augmentation, sudden subsidence, or 
complete extinction — a wavy oscillation, resembling 
wind action. 
4th. Bistre- colored clouds, assuming a segmentary 
or arch-like form, and throwing out rays of white 
light; these streaming toward the zenith, and some- 
