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 Cnscades 

 of the Columbia. After leaving Wallah-Wallah we had one or two showers of rain, but none of 

 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 1st, 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 ra}^s of li^ht, commonly called &quot;needles,&quot; 

 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 diminished 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 thrown up, resembling in every respect those observed within. 



During the continuance of this arch the &quot;needles&quot; 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 liglu, exceedingly brilliant, shot up from the horizon to the zenith, distinctly marked and sepa 

 rated irom 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 phantasm ic character to the scenes 

 entirely inappreciable to one not a witness of it. 



