Narrative of the surveying voyages of his majesty's ships Adventure and Beagle (vol.1): between the years 1826 and 1836 : describing their examination of the southern shores of South America, and the Beagles's circumnavigation of the globe

46{) BAROMETER OFF CAPE HORN. northward, causing a fall of the mercury from 29"90 to 29'56. On the day of full moon the column rose, and we had a beautiful morning, during which the high mountains of Staten Island were quite unclouded, as were also those of Tierra del Fuego. At noon, however, a fresh gale from the S.W. set in, and enveloped the land with a dense mist. No sooner had the wind changed, than the mercury rose to 29'95, but fell again the next morning ; and with the descent the wind veered round to N.W., and blew strongly with thick cloudy weather and rain, which continued until the following noon, when the wind veered to S.W., the barometer at 29"54<, having slightly risen but after the change it fell, and continued to descend gradually until midnight, when we had a fresh gale from W.S.W. When this wind set in, the mercury rose, and continued to rise, as the wind veered Avithout decreasing in strength to S.S.W., until it reached S9"95, when it fell again and the weather moderated, but without any change of wind. During the descent of the mercury, the sky with us was dull and over- cast, with squalls of wind and rain, but on shore it seemed to be very fine sunshiny weather. The colinnn now fell to 2923, and dui'ing its descent the weather remained the same, dull and showery ; but as soon as the mercury became stationary, a fresh breeze set in from the southward, with fine weather. After this to new moon the weather was very unsettled, the wind veering between South and W.S.W. ; the barometer rising as it veered to the former, and falling as it became more westerly ; but on no occasion did it pi-ecede the change. The mean height of the barometer is about 29'5. The mercury stands lowest with N.W. winds, and highest with S.E. With the wind at N.W. or northerly the mercury is low if it falls to 29 inches or 28-80, a S.W. gale may be expected, but it will not commence until the column has ceased to de- scend. It frequently, however, falls without being followed by this change. In the month of June, at Port Famine, the barometer fell to 28-17, and afterwards gradually rose to 30-5,