POLAR YEAR EXPEDITION STAGG 111 



instrumental equipment and foodstuffs, had gone ahead of us, but 

 we caught up on it at Fort Smith at the lower end of the rapids 

 along which it had been transported by a portage road. From 

 Smith we continued north down the Slave River and across the 

 Great Slave Lake till we were some 1,000 miles north of Edmonton. 

 In the early years of this century the site of the trading post at 

 Fort Rae had been moved 25 kilometers farther north into the 

 Marian Lake extension of the Great Slave Lake. The added facili- 

 ties offered by staying near the trading post made us choose the 

 new Rae for our main base. During the period of our stay, however, 

 a site almost identical with that of the 1882-83 expedition was used 

 as a subsidiary station in communication with the main base for 

 photography of »urora and also in the two summers of our stay for 

 comparison observations in terrestrial magnetism. 



We were fortunate in finding the north arm of the lake free 

 from ice at an unusually early date and so arrived at the scene of 

 our Polar Year activities by mid-June. 



Every minute of our time before August 1, 1932, the official date 

 when all the Polar Year stations were due to start their activities, 

 was occupied with the building of huts, setting up of instruments, 

 and getting them into proper working order. By arrangement with 

 the Hudson's Bay Co. we were saved the building of dwelling 

 and main observatory huts, but our magnetic work demanded two 

 huts of special type, one for the continuously recording magneto- 

 graphs and another for the control observations. Both of these had 

 to be free of magnetic material, and, though our standard magneto- 

 graphs could be completely self-compensated for temperature 

 changes, we though it best to erect them in a chamber with as small 

 a daily range of temperature as possible for double safety. 



A custom among the Dog Rib Indians in that part of Canada 

 of deserting any dwelling-place where a member of a family has 

 died, gave us a log shack which, when denuded of the large quantity 

 of iron nails used by the former owners for supporting the " wall- 

 paper ", formed a very serviceable outer shell for a multiple-walled, 

 thermally insulated chamber we built within. The outer walls of 

 this hut were subsequently mudded and heavy turf was banked up 

 around them, so that by the time the autumn snows had made still 

 another covering the insulation of the magnetograph chamber 

 within was very satisfactory. In this chamber we erected three com- 

 plete sets of magnetographs, each set recording photographically, 

 continuously and independently the variations in the three compo- 

 nents of the earth's magnetic field. One set, the standard, was of 

 the very recent pattern designed by Dr. la Cour, Copenhagen; the 

 second set, acting as a subsidiary and run at low sensitivity, was 

 loaned by Greenwich Observatory ; and the third, also of the Copen- 



