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HIRKELAND. THE NORWEGIAN AURORA POLARIS EXPEDITION, I 902 1903. 



Fig. 14. Observation-Huts at Oyrafjord Station. 



Wooden pillars of this kind, buried in this 

 manner, and exposed to fairly constant 

 humidity, and, as in this case, beyond the 

 reach of the frost, have proved quite satis- 

 factory. The instruments must be placed 

 directly upon the end-grain. 



P, PI , and PI I are the pillars for the 

 registering apparatus, PHI, PIY, and PV, 

 those for the magnetometers. //, D, and 

 V are the variometers for respectively hori- 

 zontal intensity, declination, and vertical in- 

 tensity, R is the registering apparatus and 

 L the lamp reflector. 



The drawing on the right of the plan 



shows how the magnets were placed in the instruments, in what direction the north pole of the magnets 

 pointed, and the size and shape of the magnets. The scale is about one/fifth of the actual size. 



The Observatory for Absolute Determinations. 



This was very well and practically made. 



The drawing gives a plan and elevation, and 



shows how the whole was arranged. It "will 



be seen that the house was partially buried 



in the sand. The part above the ground was 



almost entirely of glass. A square hole was 



dug in the ground, and into the corners and 



sides of this were driven 12 posts, upon which 



rested a frame, a similar frame connecting 



their lower ends upon the earth beneath the 



floor. The floor rested upon the latter frame, 



and from it, and up to the surface of the 



ground, were nailed boards, which thus formed the walls of the underground portion. Above the ground, 



grooves were cut up the sides of the posts, into which were fitted glazed window-frames. The windows 



were kept in their place by bolts. In the 

 drawing, one of these is marked K. The roof 

 was formed of three window-frames, which 

 were wedged into the beams of the roof in the 

 same way as the side windows. The roof 

 windows were kept in their place by two 

 overlapping clamped beams, one end of which 

 was attached by hinges, h, It 1 , the other end 

 being held fast by the clamps /, 7 1 , which 

 could be unhooked, and thereby allow the 

 beams to be raised, and one or all of the win- 

 dows to be removed. The side windows could 

 be removed in a similar manner. Thus the 

 Fig. 16. View from Dyrafjord Station; by moonlight. great advantage of this observatory was that 



Fig. 15. View from Dyrafjord Station; by moonlight. 



