CBUISE OF STEAMER CORWIN IN THE ARCTIC OCEAN. 



89 



July 28, 1S78, snow fell upon the hills and mountains along the coast to a depth of about a foot, 

 and extending down within 250 feet of the sea-level. This snow disappeared by noon the nest 

 day, upon which occurred an eclipse of the sun. September 7, 1880, a heavy snowfall occurred 

 on all the mountains and hills around Norton Sound, within 400 feet of the sea-level, and on the 

 17th and 18th of June, 1880, snow showers occurred at the sea-level. Nearly every winter, during 

 the last half of December or first part of January, occurs a series of southerly and easterly gales, 

 accompanied by more or less heavy rains and a temperature sometimes rising from the 40° of a 

 few days before to +46° or over. This thaw frequently lasts a week or ten days, during which 

 all the snow is melted from the ground, the sea ice is generally driven oft" shore and broken up, 

 and in the interior the smaller rivers open and are freed from ice. The most extensive thaw of 

 this character observed occurred the last of December, 1880, and first of January, 1881, when the 

 ice upon the Yukon was rendered too thin to travel upon, and many large openings appeared, 

 while the Koskoquim River rose mauy feet, exceeding the ordinary height at the spring freshet, 

 and the ice broke up and was swept away from bank to bank as in spring. These thaws are of 

 such regular occurrence at this season that the fur-traders speak of the "Christmas thaw" as a 

 settled fact, and observation justifies the belief. It is during this storm that some of the severest 

 gales of the year are usually experienced. 



DEW, FKOST, FOG, ETC. 



Clear, calm nights in spring and summer are frequently accompanied by a copious dew, the 

 grass-blades bearing large drops in the early morning. Frosts are less common, their relative 

 infrequency being due, probably, to the greater number of cloudy days during the time that frost 

 might be expected. A sudden fall of the temperature in winter, if the sky is clear, almost always 

 results in a precipitation of beautiful snow crystals of minute size. In some instances these 

 crystals become aggregated and form feathery snow-flakes of extremely loose texture. The suow 

 fog rarely occurs, however, except in perfectly calm, clear weather, with a temperature below zero. 

 At temperatures from —25° to —35° and below, it only requires a change of a few degrees to produce 

 the falling crystals. In some cases this fog consists of minute globules of ice which are barely 

 visible to the eye and are deposited upon every object presented to tliein, for this phenomenon 

 usually accompanies a slight wind when the circumstances appear unfavorable for the formation 

 of the crystals. These globules appear to still preserve the power of changing their shape even 

 at a temperature of —35° to —40°, and build up a thick coating of icy spicuke upon a feathery 

 background of frost-work upon anything presenting the slightest inequalities to the wind. The 

 spicule present their points to the wind and are often bordered with feathery frost-work. North 

 winds prevail over all others, and south winds follow in their order. 



The following list of the winds for four years preceding April 30, 1881, compiled by Mr. 

 Nelson, will give the relative frequency and the percentage of each in a series of eleven thousand 

 four hundred and sixteen observations : 



Number of calms, 633 ; total, 11.546. 



Relative frequency, .057, 100.70. 



North winds, when not caused by a return current to be mentioned hereafter, nearly always 

 produce a fall in the temperature and at the same time the sky is cleared, so that it is a well- 

 established rule, even with the natives, that a change of wind to the north will give clear weather 

 and colder, while to the south or southeast gives warmer weather with the sky obscured and 

 commonly accompanied by rain or suow, according to the season. East winds are also rain or 

 snow winds, but less marked than the south or southeast. If the wind blows from the north for a 

 time, and then change by the northeast by east to south, a rise in the temperature with more rain 

 may be expected in summer, or warmer weather with snow in winter. Should the wind change 

 S. Ex. 204 12 



