The Sun.
London, England, 1860-09-21 00:00:00

SIGNS OF THE WEATHER

The following communication has been forwarded
:o us for insertion by the National Lifeboat Insti-

:ution :

Public attention has frequently been called to the inva.
luable use of a barometer for indicating a coming storm.
It not unfrequently happens that a notice of a gale is given
by a barometer two or three days before it actually takes
place. It seems plain that with such powers provi-
dentially placed in our hands, the calamities now endured
by our fishermen and coasters might in many instances be
avoided. A good barometer in a public situation would warn
them in time what to expect, and they would thus be fre-
quently able to avoid the terrible consequences of storms,
so often at present proving fatal to them.

Rear-Admiral Fitzroy, F.R.S., has compiled so tho-
roughly practical a manual for the use of a barometer, that
seafaring men or fishermen may soon become perfectly
familiar with the indications of the instrument. Some time
since, as chief of the Meteorological Department of the Board
of Government, he obtained the sanction of the Board of
Trade to supply some 40 of our poorer fishing villages with
barometers, some of which have been of good service to the
fishermen.

It is, however, evident that something more is absolutely
required in order to make barometers generally available
for our fishing and seafaring population ; it is, therefore,
satisfactory to find that this important subject has been
taken up practically by the National Lifeboat Institution.
Admiral Fitzroy, who is a member of the committee,
gives the undertaking his cordial and valuable co-operation.
Tho admiral's own manual, as well as large placards con-
taining extracts from it, will be extensively circulated on the
coast, fully explaining the working of the barometer.
It is proposed to fix such barometers, wherever found
useful and practicable, in suitable positions at the society's
lifeboat houses, which are situated on most parts of the
coasts of the 'United Kingdom.
To carry out effectually this plan, the institution has for-
tunately the machinery at hand, for to each of its lifeboats
is attached a permanent coxswain, who receives a small an-
nual salary for the superintendence of the working part of
the establishment. It is proposed to instruct such of these
men as are found capable in the indications of the barome-
ter, so that they may act as so many storm warners in the
towns or villages in which they reside.
It 1:11 be readily conceived that beneficial results may
accrue to life and property among our hardy coast popula-
tion from this important step. It is notorious that at the
present day the masters of our smaller coasting fish;ng
craft hardly ever think of consulting a barometer, if indeed
they have an opportunity to do so.
It is estimated that a good barometer cannot bo fixed at
a lifeboat house under £6, so that it will require a consider-
able sum to carry out effectually the above plan of the in-
stitution.

A benevolent gentleman has presented VO to the institu-
tion to be applied specially for the purchase of barometers
for the lifeboat stations, and we cannot doubt that the pub-
lic will readily make up what may be further required.
The making of the barometers will probably be intrusted
to Messrs. Negretti and Zambra, who have supplied the
before named 40 instruments to the Board of Trade, for
various fishing stations on the northern coast, and a number
to the British Meteorological Society for the coast of Nor-
thumberland. The object of thelinstitution will be to obtain
a good instrument, ono that will not easily get out of order
in travelling, or require renovating at frequent intervals ;
in short, a barometer that having been once set up at a
lifeboat station will be a permanent instrument of instruc-
tion, and one that will not entail any future expense to the
society. In order to meet these requirements the makers
have therefore introduced the following changes in the re-
gular instruments, which we think may fairly come under
the head of important improvements. The brass or
ivory scales that barometers are generally furnished with
are here replaced by a substantial plate of porcelain,
on which the degrees and figures are legibly engraved and
permanently blackened in, so that, as far as the figures and
divisions are concerned, there will be no danger of their
becoming faded or obliterated. This is a very important
improvement, especially for an instrument that has of
necessity to be placed in an exposed situation, where the
mariner may be able to consult it any time, even in the
middle of the night, should he wish to do so.
The mercurial tube of the barometer is of large diameter,
so as to render the mercury easily visible, and show the
slightest variation, and is so constructed that tho liability
of air entering it is, we may say, entirely obviated ; for if
air by any means finds its way up the tabo of a barometer,
let the quantity be ever so small, the indications of the in-
strument are erroneous, and no longer to be relied on. To
prevent the admission of air to the vacuum above the mer-
curial column, a trap is laid at the bottom of the tube, near
the part called the cistern, so that if any air should find its
way into the tube it cannot possibly pass the trap, but is
there detained, and the instrument is no way deteriorated or
injured by its presence. These tubes are moreover "boiled."
The operation of boiling a barometer tube consists in filling
the tube with mercury, and then causing the mercury to
bell by placing the full tube over a charcoal fire; it is an
operation attended with considerable risk to the tube and
operator, and for this reason is seldom carried into practice,
and in the majority of barometers made it is altogether ne-
glected. The size of the mercurial column averages 4-10Cas
of an inch, so that altogether instruments of the greatest
efficiency will bo obtained. A great change has also been
effected in the old system of marking the scales with Fair,
Change, Bain, &c., words which in reality have :often a
tendency to mislead, and to throw discredit on barometrical
indications.
The National Lifeboat Institution has recently diffused
useful information on the treatment of the apparently
drowned, and on the management of boats in heavy surfs
and broken water, which has already been productive of
public benefit, not only on the coasts of the British Isles,
but also over other parts of the globe.
It may also be fairly anticipated that similar beneficial
results will ensue from the establishment of these barome-
ters at its lifeboat stations.

We subjoin a synopsis of Admiral Fitzroy's Instruc-
tions on the use of Barometers. These instructions will
be printed on large placards for use on the coast, wherever
the barometers of the National Lifeboat Institution are
placed, and elsewhere :
" The barometer should be set regularly, by a duly au-
thorised person, about sunrise, noon, and sunset.
" The words on old scales of barometers should not be
so much regarded for weather indications as the rising or
falling of the mercury ; for if it stand at changeable, and
then rise towards fair, it presages a change of wind or
weather, though not so great as if the mercury had risen
higher; and, on the contrary, if the mercury stand above
fair and then fall, it presages a change, though not to so
great a degree as if it had s'-ood lower ; besides which, the
direction and force of wind are not therein noticed.
1 It Is not from the point at which the mercury may
stand that we are alone to form a judgment of the state of
the weather, bit from its rising or falling ; and from the

movements of immediately preceding days as well as

hours—keeping in mind effects of change of direction, and
dryness, or moisture, as well as alteration of force or
strength of wind.
"It should always be remembered that the sate of the
air foretells coming weather, rather than shows the weather
that is present—(an invaluable fact too often overlooked)—
that the longer the time between the signs and the change

foretold by thew, the longer such altered weather will lasi;
and, on tho contrary, the less the time between the warning
and the change, the shorter will be the continuance of such

foretold weather.

" If the barometer has been about its ordinary height,
say near 30 inches at the sea-level, and is steady or rising,
while the thermometer falls, and dampness becomes less—
north-westerly, northerly, or north• easterly wind, or less
wind, less rain or snow ma! be expected.
" On the contrary, if a fall takes place with a rising ther-
mometer and increased dampness, wind and rain may be
expected from the south-eastward, southward, or south-
westward.
"A fall with low thermometer foretells snow.

" When the barometer is rather below its ordinary
height, say down to near 29i inches (at sea-level), a rise
foretells less wind, or a change in its direction towards
the northward—or less ivot ; but when it has been very
low, about 29 inches, the first rising usually precedes or
indicates strong wind—at times heavy squalls—from the
north-westward, northward, or north• eastward; after
which violence a gradually-rising glass foretells improv-
ing weather, if the thermometer falls ; but if the warmth
continue, probably the rind will back (shift against the
sun's course), and more southerly or south-westerly wind
will follow, especially if tle barometer's rise is sudden.
" The most dangerous shifts of wind, or the heaviest
northerly gales, happen soon after the barometer first rises
from a very low point; or if the wind veers gradually at
some time afterwards.

" Indications of apprcaching changes of weather, and
the direction and force or winds are shown less by the
height of the barometer than by its falling or rising.
Nevertheless, a height of more than thirty (30.0) inches
(at the level of the sea) is indicative of fine weather and
moderate winds ; except from east or north, occasionally.
"A rapid rise of Ihe barometer indicates unsettled
weather; a slow moveseent, the contrary; as, likewise, a
steady barometer, which, when continued, and with dry-
ness, foretells very fine weather.
" A rapid and considerable fall is a sign of stormy
weather, and rain or Enow. Alternate rising and sinking
indicates unsettled andihreatening. weather. .

"The greatest depressions of the barometer are with
gales from S.E., S., or S.V. ; the greatest elevations, with
wind from N.W., N., cr N.E., or with calm.
" A sudden fall of tLe barometer, with a westerly wind,
is sometimes followed by a violent storm from N.W., or
N., or N.E.

"If wind sets in from the E. or S.E., and the gale veep
by the mouth, the barometer will constinue falling util the