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. 8 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 : j 



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 little force the rods could -_-. 



be torn loose. The observations met with most diffi- H 



culties during the warm season, when the temperature I." 



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



soft and viscous, and in a little while the holes would r_~. 



become narrower owing to the slow viscous movement 3. 



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- 7, 



modation. For each observation the rods were hauled 



1 As the bore-holes had to be fairly narrow, the thermometers would easilyi'freeze 

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

 thermometer, especially during the summer. 



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

 mention of the accident in my journals. 



