NO. 17.] 



THE TEMPERATURE OF THE POLAR ICE. 



541 



but as they would easily stick fast there when left for some time, they were 

 often difficult to recover, and had sometimes to be dug out. ' During an operation 

 of this kind, one of the thermometers was broken. ^ I did not therefore, on 

 the whole, consider the above method satisfactory. After several experiments, 

 I adopted the following method. The bulbs of some ordinary thermometers 

 (Soderbergs sling-thermometers) used for meteorological observations were 

 enclosed in thick lumps of paraffine-wax. These thermometers were mounted 

 in suitable holes at the ends of round wooden rods (in a manner similar to 

 that of bath-thermometers in their wooden mounting). The rods were at least 

 20 cm. longer than the bore-holes in which they were 

 placed, in order to give a handle by which they could 

 easily be hauled up. The rods at several places were 

 surrounded by muffs or cuffs of reindeer-skin with thick 

 hair in order to prevent vertical circulation of air in the 

 bore-holes. One such muff was placed close above the 

 thermometer, another at the surface of the ice, and if 

 the bore-holes were deep, one or two in between. The 

 arrangement was as shown in the figure. In cold weather, 

 the reindeer-hair of these muffs might freeze fast to the 

 sides of the holes, but by a Uttle force the rods could 

 be torn loose. The observations met with most diffi- 

 culties during the warm season, when the temperature 

 of the ice was relatively high. The ice was then very 

 soft and viscous, and in a little while the holes would 

 become narrower owing to the slow viscous movement 

 of the ice, and had to be rebored at certain intervals. 

 It often happened that the rods then stuck in their 

 holes, and had to be dug out. The rods with the 

 thermometers were always left in their holes in order 

 to give the thermometers the necessary time for accom- 

 modation. For each observation the rods were hauled 



ii:;v 



As the bore-holes had to be fairly narrow, the thermometers would easilyjfreeze 

 fast, or the plastic or viscous ice would often, after a few days, close round the 

 thermometer, especially during the summer. 



I believe this was in March, 1894, but unfortunately I have not been able to find a 

 mention of the accident in my, journals. 



