96 CKUISE OF STEAMER CORWIN IN THE ARCTIC OCEAN. 



in spring the greatest number occur when the air is filled with ice crystals. Halos occur rather 

 commonly from the frequent formation of haze. In one instance, while. reading the anemometer, 

 during a white fog, Mr. Nelson says, " J saw on the side from the sun my shadow faintly traced 

 upon vapor, and surrounding it a perfect and bright white halo." Imperfect halos of this kind 

 were several times observed. 



TWILIGHT. 



In autumn and during the first part of winter, and again towards the end of winter and in 

 spring, occur beautifully-colored twilights, the shades of which are only equaled by the gorgeous 

 richness of tints whose fleeting touches change the clouds into a beautiful mass of colors as the 

 sun sets or rises. 



MIRAGE AND HEAT BATS. 



During the fine weather from the last of February until into July most of the clear days are 

 accompanied by more or less mirage, which is generally strongest on cool, clear days in March 

 and on fine, warm days in May and June. The coast hills, 30 to 75 miles away, are lifted up and 

 contorted into the most fantastic shapes, which constantly assume new forms with Protean ra- 

 pidity until the whole landscape appears but a form of air. The least change in one's altitude pro- 

 duces a disproportionate change in the scene. Tall pinnacled hills, apparently hundreds of feet 

 high, are made to melt away and totally disappear under the horizon by the observer descending 

 about 15 feet from the first point of view ; and the changes in outline are equally abrupt and sur- 

 prising. During the entire year, upon pleasant days, the air is constantly vibrating more or less 

 appreciably to the eye, but during the clear, intensely cold days in the last two thirds of winter 

 these vibrations are so energetic that everything on or near the surface of the ground becomes, at 

 a distance of about 2 miles, blended in an indistinct, tremulous blur. 



GENERAL NOTES. 



CHANGE OF SEASONS. 



As in most other places in high latitudes there is no long gradation from season to season, but 

 in place thereof are two well-marked periods — a long winter of about seven months extending 

 from in October until well into May, with a five-month summer. The winter has by far the 

 best weather, as there are long periods of beautifully clear days, which are welcomed in spite 

 of Hie usually accompanying intense cold. The summer is rendered very disagreeable by the 

 large number of cold, misty rains and the low, overhanging clouds which appear to shut down 

 all about like a leaden cover. 



TIDES. 



The ordinary tides are small and give a rise and fall of only about 2 to 3 feet, but the 

 winds from either north or south produce a striking variation. A long continued and heavy 

 gale from the south raises the water of Norton Sound at least 10 feet above ordinary tide-mark 

 and floods large stretches of the low coast to the southward. Some of the heaviest of these 

 gales occur during winter, and it is not rarely that the sea, covered with heavy ice, sweeps over 

 the low coast lands between the Yukon and Kuskokvim Rivers for miles, and native villages 

 have been thus destroyed, and many of their inhabitants, within a few years. As the tide falls 

 the ice, from 3 to 4 feet thick, is left stranded over the low laud. A light south wind is 

 sufficient to raise the tide from a few inches to several feet above the ordinary. North winds 

 affect the tides in proportion to their strength, exactly in the reverse of the south wind, and 

 when in fall long-continued and strong gales from this direction occur the shallow bays are 

 laid bare, dark reefs exposed, and a general fall of about 8 feet occurs in the water. It is to 



