392 METEOROLOGY OF THE CASCADES. 
morning had passed, was much the most agreeable we experienced, although it was late in the 
season, and the latitude nearly 49°.. This continued, with slight exceptions, during our descent 
of the valley of Colville river, and during the first of our stay at Fort Colville. The mornings, 
however, were, with scarcely an exception, cold and raw; ice formed in the buckets, and heavy 
frosts were visible. 
The lowest temperature indicated by the thermometer, during the march, was on the 23d of 
October—8° half an hour before sunrise, 10° at sunrise. During the preceding day the ther- 
mometer read below 32°. The frost on that day was the heaviest I have ever seen; it re- 
mained distinctly visible until nearly noon. Snow fell on the night of the 23d and morning of the 
24th to the depth of six inches, the only snow observed throughout the march. It was succeeded 
by a rain and thaw, which removed every vestige of it in a few days. ‘The valley back of Col- 
ville is well sett ed, and the inhabitants assured me that it was unusual to have snow so early. 
Severe frost attended us from this time, with few exceptions, until our arrival at the Cascades 
of the Columbia. After leaving Wallah-Wallah we had one or two showers of rain, but none ot 
long continuance until the expedition reached the Cascades. I learned from the Indians, and old 
residents of the upper portion of the Territory, that but little rain falls above latitude 46°. 
Thunder and lightning, a phenomenon of rare occurrence in this climate, were observed only 
two or three times. It is worthy of remark that the Indians assert thunder and lightning to have 
been introduced by the whites. 
Aurora Borealis was faintly observed on two occasions—on September Ist, and during the night 
of the 27th of the same month. I extract from my journal the notes made on the latter date. 
September 27, 1853.—Aurora Borealis was observed, commencing about 7 p. m., in the north 
horizon. The phenomenon first exhibited was that of rays of light, commonly called ‘“ needles,” 
shooting up, distances varying from 8° to 15°, alternately brightening and darkening. This 
appearance gradually extended towards the east, until it was exhibited throughout the horizon 
from north to north by east. The light gradually din.inished in brightness, and when nearly 
blended with the general color of the horizon, (purple gray) it took the form of an arch, with a 
rise of about 7° and span of 40°. This arch gradually dilated in length and height until it 
became almost 90° in length and from 15° to 18° high. 
During the earlier part of the time the arch was visible, the horizon enclosed within it was 
perfectly dark, and the aurora increased in brilliancy, until it became beautifully distinct and 
finely marked. 
As the arch gradually assumed its greatest size, the same phenomenon first observed became 
again visible, and within the arch strong flashes of light, some needle-like in shape, others 
broader and less fine, but gradually converging to a point until they reached their greatest altitude ; 
then falling until they became nearly indistinct, and again reviving in their original brilliancy. 
This commenced in the eastern point of the arch, or was just observed there, and extended 
itself over the whole enclosed horizon. Outside of the arch, at its northern extremity, bright 
flashes of light were thown up, resembling in every respect those observed within. 
During the continuance of this arch the “needles” of light did not attain a greater height than 
12°. About 11 p. m. the arch had disappeared, and given place to an appearance of similar 
nature to the first observed, but on a much grander and more beautiful scale. Narrow streams 
of lighi, exceedingly brilliant, shot up from the horizon to the zenith, distinctly marked and sepa- 
rated rom each other by dark shadows intervening. 
This light had a waving, tremulous motion; the shadows, moving with the light, gave an 
appearance of panoramic views passing from left to right. This last phenomenon was one of 
exquisite beauty. The moving of the light, its alternate darkening and again becoming brilliant, 
and the flashes, shooting far up into the heavens, gave a phantasmic character to the scenes 
entirely inappreciable to one not a witness of it. 
