Dec. 1857. THE AURORA. 63 



Evaporation goes on through ice from the water under- 

 neath it. The interior of each snow-hut is coated with 

 crystals, although the ice upon which the huts are built is four 

 feet thick : but when no longer in contact with, that is, 

 floating upon, the water, I cannot discover any evaporation 

 from ice. For instance, a canvas screen on deck which 

 became wet by the sudden thaw last month still remains 

 frozen stiff. 



14///.— Of late there has been much damp upon the lower 

 deck. This has now been remedied by enclosing the hatchway 

 within a commodious snow-porch ; and, instead of the steam 

 and vapour of the inhabited deck being condensed into 

 moisture about the hatchway as heretofore, it now meets 

 the downward rush of cold air in the porch, and is there 

 converted into minute particles of snow; this porch also 

 diminishes the escape of heat. 



19///.— Position, 74 5' N., 66° 27' W. 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 respectively no, 140, and 180 miles distant 

 from us. 



Frequent auroras during the last two days. Yesterday 

 morning it was visible until eclipsed by the day-dawn at 10 

 o'clock. Although we could no longer see it, I do not 

 think it ceased ; very thin clouds occupied its place, through 

 which, as through the aurora, stars appeared scarcely dimmed 

 in lustre. I do not imagine that the aurora is ever visible 

 in a perfectly clear atmosphere. I often observe it just 

 silvering or rendering luminous the upper edge of low 

 fog or cloud banks, and with a few vertical rays feebly 

 vibrating. 



