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cl, 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, hut 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 AV.S.W.
When this wind set in, the mercury rose, and continued to
rise, as the wind veered without deereasing iu strength to
S.S.W., until it reached 29"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 overcast,
with squalls of wind and rain, but on shore it seemed to
be very fine sunshiny weather.
The column now fell to 29'23, and during 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 precede the change.
The mean height of the barometer is about 29'S.
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 he expected,
but it will not commence until the column has ceased to descend.
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,
which was followed by cold weather, in which the thermometer
stood at 12°.
The following Table shews the mean temperature and pressure
as registered at the Observatory at Port Famine in the
Strait.
1828. Temperature, I^ressure.
February ......................... .IM 29-40
March .............................. 49-4 29-64
A p r il.................................. 41-2 29-57
May .................................. 35-5 29-30
June .................................. 32-9 29-28
July .................................. 33-0 29-57
A u g ;u s t............................ .33-2 29-28
The difficulties that present themselves to Navigators in
passing round Cape Horn, as well from adverse winds as the
severe gales and heavy sea to which they are exposed, are so great,
that the Strait of Magalhaens has naturally been looked to as
a route by which they may be avoided. Hitherto no chart has
existed in which much confidence could be placed ; but by the
present survey, the navigation through it, independent of wind
and weather, has been rendered much easier; since a correct
delineation of its shores, and plans of the anchorages, have
been made; and in the preceding pages, sufficient descriptions
of them have been given to assure the navigator of his place,
and furnish him with advice as to his proceedings. The local
difficulties therefore have been removed; but there remain much
more serious ones, which I should not recommend a large, or
even any but a very active and fast-sailing square-rigged
vessel to encounter, unless detention be not an object of importance.
For a square-rigged vessel bound through the Strait, the
following- directions will be useful;—
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