THE recent sunsets were nearly or quite as remarkable in the Rocky Mountain region as they were in Europe, and the phenomena were very similar. There was the same peculiar fire-red after-glow continuing for two hours after sunset, &c. These unusual appearances began to attract attention soon after the middle of November. They were most brilliant during the last week of November, but continued at intervals until early in January. The carefully kept meteorological record of Prof. F. H. Loud, of Colorado College, shows that the atmospheric pressure varied considerably during the latter part of November, but there was no apparent accompanying change in the after-glow. The sunrises were also quite brilliant, but less so than the sunsets. Late in November I began to observe the wide chromatic belt which surrounded the sun, and at midday usually reached from near the sun to the horizon. Somewhat similar appearances and chromatic halos are not uncommon here, and it was not until after several weeks of comparison of colours that I became convinced that the tints seen around the sun during the time of the remarkable sunsets were somewhat different from those ordinarily seen. By degrees the brick, or fire-red, and other abnormal tints of the twilight hours have given place to the ordinary prismatic colours, and a similar but less marked change could be seen in the colours observed near the sun during the daytime. These day colours were brightest when the sky was overcast with thin clouds or filmy cirri, though plainly visible when there was no cloud to be seen. The prevailing day tint is usually a peculiar dull purple, but during the time of the red after-glow the common colour was duller, more like a yellowish brick-dust.