in its direction towards the
Northward,--or less wet; but when the mercury[12] has been low, say near
29 inches--the first rising usually precedes, and foretells, strong
wind--(at times heavy squalls)--from the North-westward--Northward--or
North-eastward--_after_ which violence a rising glass foretells
improving weather--if the thermometer falls. But, if the warmth
continue, probably the wind will back (shift against the sun's course),
and more Southerly, or South-westerly wind will follow. "Backing" is a
bad sign, with any wind.

The most dangerous shifts of wind, and the heaviest Northerly[13] gales
happen after the mercury first rises from a very low point.

Indications of approaching changes of weather, and the direction and
force of winds are shown less by the height of mercury in the tube, than
by its falling or rising. Nevertheless, a height of about 30 inches (at
the level of the sea) with a continuance of it, is indicative of fine
weather and moderate winds.

The barometer is said to be _falling_ when the mercury in the tube is
sinking, at which time its upper surface is _sometimes_ concave or
hollow. The barometer is _rising_ when the mercurial column is
lengthening; its upper surface being then, as in _general_, convex or
rounded.[14]

A rapid rise of the barometer indicates unsettled weather. A slow rise,
or steadiness, with dryness, shows fair weather.

A considerable and rapid fall is a sign of stormy weather and rain.
Alternate rising and sinking show very unsettled weather.

The greatest depressions of the barometer are with gales from the S.E.,
Southward, or S.W.; the greatest elevations, with winds from the N.W.,
Northward, or N.E., or when calm.

Although the barometer generally falls with a Southerly, and rises with
a Northerly wind, the contrary _sometimes_ occurs; in which cases the
Southerly wind is dry and the weather fine; or the Northerly wind is wet
and violent.[15]

When the barometer sinks considerably, high wind, rain, or snow will
follow: the wind will be from the Northward if the thermometer is low
(for the season)--from the Southward if the thermometer is high.

Sudden falls of the barometer, with a Westerly wind, are sometimes
followed by violent storms from N.W. or North.

If a gale sets in from the Eastward or S.E., and the wind veers by the
South, the barometer will continue falling until the wind becomes S.W.,
when a comparative lull may occur; after which the gale will