Page:Polar Exploration - Bruce - 1911.djvu/37

Rh ice, there are even in summer time wintry conditions; so much so that most of the precipitation that occurs is in the form of snow instead of rain. In midsummer, when cruising in the vicinity of the Antarctic continent, blizzards off the land cause the temperature to fall even below zero Fahrenheit, and in winter on Antarctica itself a temperature has been recorded as low as 68 degrees below zero Fahrenheit, or 100 degrees of frost. The lowest air-temperature has been recorded at Verkhoyansk in Siberia, namely, −90° F., or 122 degrees of frost. From this it will be seen that, as most of the Antarctic land lies well within the Antarctic Circle, practically all precipitation must be in the form of snow, and that little melting takes place except where the sun gets very favourable play. On black rocks the sun's heat may be absorbed, and in sheltered corries, where there may be considerable melting, resulting in the formation of small burns and tarns.

On the rocks a few lichens will grow; on softer, more crumbly, and flatter expanses a few mosses may thrive, and amongst these mosses and in the tarns a few minute forms of animal and vegetable life will flourish, which have sharp alternate spells of activity or passivity according as the temperature is above or below the freezing-point.