316 
THE AURORA. 
In the auroras seen by tfie American Expedition, a 
distinct scintillation was rare ; and I observed a pris- 
matic tinting in only a single instance. The move- 
ments of the auroral bands were so wave-like that 
they were at once suggestive of wind-action, although 
no correspondence was noted between them and the 
direction of the lower atmospheric currents. This ef- 
fect, which I had repeated occasion to observe, height- 
ened the resemblance of our Arctic aurora to illumin- 
ated cirro-stratus, and, I confess, always impressed me 
with its want of altitude. 
Let me condense from my Journal and Meteorolog- 
ical Record a description of the aurora, as we some- 
times saw it. 
The 2d of February came to us with sunshine, the 
atmosphere in yellow light, and full of minute spicu- 
Ise; our thermometers at 32°, my spirit standard at 
34°, and Grreen's mercurial at 38°. Drawing the fin- 
ger through the mercury of our artificial horizon gave 
the sensation of scalding water. The evaporation and 
increased dryness were very perceptible : a brass cli- 
nometer, which was coated with hoar-frost, became 
perfectly clean on exposure to the solar ray. The 
haze disappeared from the southern horizon, and the 
sky became strikingly clear. As late as half past eight 
A.M., I saw the North Star in the zenith, the tail of 
the Bear, and stars of the third and fourth magnitude. 
By nine every one had gone, leaving Arcturus and 
Capella in possession of the field. 
Between the hours of six and eight P.M., we had 
an interesting display of the aurora. It was of a lu- 
minous white, not much more marked than any of 
the isolated nebulae seen through a telescope, which 
it indeed resembled. This white light stretched in 
