NO. 7.] INTRODUCTION. 9 



vatory was completed, an ice pillar was introduced into it, 1.4 metres 

 high; and on the top of the pillar a block of wood was frozen fast, and the 

 instrument screwed to it. 



As a defence against bears during the taking of observations, a weapon 

 was always at hand, generally a revolver, which was either stuck vertically 

 into a hole in the ice between the legs of the stand, perpendicularly below 

 the centre of the instrument, or lay horizontally in the same place with its 

 butt-end pointing westwards. Several observations were made with the re- 

 volver in various positions, without any proof being obtained of any decided 

 influence on the readings. When the ice observatory was taken into use, 

 the revolver was laid on the ice to the north, at a distance of 3 metres from 

 the instrument, on a level with the foot of the pillar, and, as before, with 

 the butt-end towards the west. When Lieut. SCOTT-HANSEN had a different 

 weapon with him, it lay on the ice at a distance of about 30 or 40 paces 

 from the instrument. 



