METHODS OF WORK. 15 



In ''mushing," the best progress is marie in relatively cool weather, at a tem- 

 perature 10° or 12° below zero. As the atmosphere warms under the midday sun, 

 the dogs, especialh 7 the natives, pant and become tired or lazy, and can not be 

 urged. On a long trip, under reasonable conditions, 25 miles is a good average 

 day's drive. In one instance, where the trail was good, 46 miles were covered 

 by the Survey party in a single da}'. The mail carriers on the lower Yukon are 

 known in exceptional instances to have made as high as 60 miles, the record for 

 the Yukon country. 



Camping. — During the last two years, sled journeys on the upper Yukon have 

 been rendered less arduous by the so-called road houses, which are located at points 

 a fair day's drive apart, and which consist usually of a log cabin and a dog kennel. 

 Though the accommodations are of the crudest order, these places facilitate progress 

 by affording the weary traveler much-needed shelter and rest, and by lessening the 

 amount of outfit and supplies he is compelled to transport on a long journey. The 

 rates charged by these road houses average about 11.50 a meal. 



Where there are no road houses, as was the case beyond Fort Yukon, the traveler 

 at the end of the day's drive selects his camp spot for the night, and, unless provided 

 with tent and stove, digs a hole through three or four feet of snow to the 

 ground for a fireplace. As a shovel is rarely carried, the snow is scooped out with 

 an axe and snowshoes. In sleeping on the snow and ice, spruce boughs, where 

 available, form a desirable mattress. A light-weight tent, provided with broad 

 bottom flaps and a closable entrance, besides affording protection from storm and 

 cold, is useful in keeping the dogs from lying on one's bedding or person, as they are 

 wont to do on a cold night. A light-weight sheet-iron stove, suited for cooking 

 inside the tent, is very desirable, but not indispensable, as an outdoor fire is usually 

 required to cook the dog feed. 



Chronologic summary of operations. — After doing some triangulation and topo- 

 graphic work in the KoyUkuk Valley, principally between the Arctic Circle and the 

 sixty-seventh parallel, the party waited at Bergman for the disappearance of the 

 snow and ice — the "break-up," as it is called; for the sheet of soft snow or slush, 

 several feet in thickness, which everywhere overspreads the country during the thaw 

 period of spring renders travel of every kind at that time impossible. Owing to the 

 heavy snowfall of the previous winter and the lateness of the spring, the break-up 

 period of 1901 was of unusual length, extending from the middle of May to June 6, 

 about twenty-five days. During this time some astronomic observations and other 

 investigations of a local nature were made. 



Except its arching feature, the breaking up of the ice on the Koyukuk, as 

 observed by the writer at Bergman, differed but little from that seen on most 

 of the large rivers in northern United States. As the stream beneath the ice 

 became swollen and distended its ever-increasing hydrostatic pressure gradually 



