I studied the wind blowing along the ridge yesterday and came to the conclusion that a comparatively thin shaft of air was moving along the ridge from Erebus. On either side of the ridge it seemed to pour down from the ridge itself – there was practically no wind on the sea ice off Pram Point, and to the westward of Hut Point the frost smoke was drifting to the N.W. The temperature ranges about zero. It seems to be almost certain that the perpetual wind is due to the open winter. Meanwhile the sea refuses to freeze over.
Wright pointed out the very critical point which zero temperature represents in the freezing of salt water, being the freezing temperature of concentrated brine – a very few degrees above or below zero would make all the difference to the rate of increase of the ice thickness.
Yesterday the ice was 8 inches in places east of Cape Armitage and 6 inches in our Bay: it was said to be fast to the south of the Glacier Tongue well beyond Turtleback Island and to the north out of the Islands, except for a strip of water immediately north of the Tongue.
We are good for another week in pretty well every commodity and shall then have to reduce luxuries. But we have plenty of seal meat, blubber and biscuit, and can therefore remain for a much longer period if needs be. Meanwhile the days are growing shorter and the weather colder.
|“Dr Simpson’s Laboratory”|