78 SNOW HUTS. Chap. Y. 



knowledge is almost indispensable. Upon a 

 calm day the temperature of tlie external air 

 being — 33°, within a snow hut the thermometer 

 stood 17° higher, this important difference being 

 due to the transmission of heat through the ice 

 from the sea beneath. 



Evaporation goes on through ice from the 

 water underneath it. The interior of each snow 

 hut is coated with crystals, and the ice upon 

 which the huts are built is four feet thick, but 

 when no longer in contact with water I cannot 

 discover any evaporation from ice. For in- 

 stance, a canvas screen on deck which be- 

 came wet by the sudden thaw last month still 

 remains frozen stiff. 



14<A. — Of late there has been much damp 

 upon the lower deck. This has now been re- 

 medied by enclosing the hatchway within a 

 commodious snow-porch, which serves as a con- 

 denser for the steam and vapour from the in- 

 habited deck below. 



Idth. — Light N.W. winds, with occasional 

 mists ; the temperature is comparatively mild : 

 -12° to -25°. 



It is now the time of spring-tides ; they 

 cause numerous cracks in the ice, but why so, 

 at such a great distance from the land, I cannot 

 explain. The three nearest points of land are 



