PUBLIC attention has frequently been called to the invaluable 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, placed providentially 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 could thus be frequently 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 thoroughly 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 Government, he obtained the sanction of the BOARD OF TRADE to supply some forty of our poorer fishing villages with barometers, some of which have been of great service to the fishermen.

His Grace the DUKE OF NORTHUMBERLAND, K.G., has also, jointly with the Meteorological Society, recently provided barometers for some of the principal fishing-stations on the Northumberland coast, under the superintendence of JAMES GLAISHER, Esq., F.R.S., of the Royal Observatory, Greenwich.

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 LIFE-BOAT INSTITUTION.

Admiral FITZROY, who is a Member of its Committee, and Mr. GLAISHER, have promised to give the undertaking their cordial and valuable co-operation. Admiral FlTZ-ROY's own Manual, as well as large placards containing extracts from it, will be extensively circulated on the coast, fully explaining the working of the barometer.

It is proposed to fix such instruments, 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, fortunately, the machinery at hand, for to each of its life-boats is attached a permanent coxswain, who receives a small annual salary for his superintendence of the working part of the lifeboat establishment. It is proposed to instruct such of these men as are found capable, in the indications of the barometer, so that they may act as so many stormwarners in the towns or villages in which they reside.

It will be readily conceived what beneficial results may accrue to life and property among our hardy sea-coast population from this important step. It is notorious that at the present day the masters of our smaller coasting and fishing craft hardly ever think of consulting a barometer, if indeed they have opportunity to do so.

It is estimated that a good barometer cannot be fixed at a life-boat house under 61., so that it will require a considerable sum to carry out effectually the above plan of the INSTITUTION.

A benevolent gentleman has presented to the Institution 50L, to be applied specially to the purchase of barometers for its life-boat stations; and we cannot doubt that the public 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 beforenamed 40 instruments to the BOARD OF TRADE, for various fishing stations on the northern coast, and also a number to the British Meteorological Society, for the coast of Northumberland. The object of the Institution will be to obtain a good instrument, and one 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 life-boat station, will be a permanent instrument of instruction, 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 regular 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 divisions and figures 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 position, where the mariner may be able to consult it at 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 the liability of air entering it, is, we may say, entirely obviated: for if air by any means find its way up the tube of a barometer, let the quantity be ever so minute, the indications of the instrument are erroneous, and no longer to be relied on. To prevent the admission of air to the vacuum above the mercurial 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 in no way deteriorated or injured by its presence. These tubes are, moreover, "boiled." The size of the mercurial column averages four-tenths of an inch: so that, altogether, instruments of the greatest efficiency will be obtained. A great change has also been effected in the old system of marking the scales with Fair, Change, Rain, &c.—words which in reality have often a tendency to mislead, and to throw discredit on'barometrical indications.

The plan to be adopted in the life-boat barometer is shown in the accompanying engraving. This has been arranged systematically.

The NATIONAL LIFE-BOAT 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 barometers at its lifeboat stations.

We subjoin a synopsis of Admiral FITZROY'S Instructions on the use of Barometers.

These instructions will be printed on large placards for use on the coast, wherever the barometers of the NATIONAL LIFE-BOAT INSTITUTION are placed, and elsewhere:— " The barometer should be set regularly by a duly-authorized 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 stood lower: besides which, the direction and force of wind are not therein noticed.

" 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, but 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 state 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 them, the longer such altered weather will last; and, on the 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 thirty inches at the sea-level, and is steady or rising, while the thermometer falls, and dampness becomes less,—north-westerly, northerly, or northeasterly wind, or less wind, less rain or snow may be expected.

" On the contrary, if a fall takes place with a rising thermometer and increased dampness, wind and rain may be expected from the south-eastward, southward, or southwestward.

" A fall with low thermometer foretells snow.

" When the barometer is rather below its ordinary height, say down to near twentynine inches and a half (at sea-level), a rise foretells less wind, or a change in its direction towards the northward—or less wet; but when it has been very low, about twentynine 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 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, especially if the 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 approaching changes of weather, and the direction and force of 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 the barometer indicates unsettled weather; a slow movement, the contrary; as, likewise, a steady barometer, which, when continued, and with dryness, foretells very fine weather.

" A rapid and considerable fall is a sign of stormy weather, and rain or snow. Alternate rising and sinking indicates unsettled and threatening weather.

" The greatest depressions of the barometer are with gales from S.E., S., or S. W.; the greatest elevations, with wind from N.W., N., or N.E., or with calm.

" A sudden fall of the 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 veers by the south, the barometer will continue falling until the wind is near a marked change, when a lull may occur; after which the gale will soon be renewed, perhaps suddenly and violently, and the veering of the wind towards the N.W., N., or N.E., will be indicated by a rising of the barometer, with a fall of the thermometer.

" After very warm and calm weather, a storm or squall, with rain, may follow; likewise at any time when the atmosphere is heated much above the usual temperature of the season.

" Not only the barometer and thermometer, but appearances of the sky and clouds should be vigilantly watched.

" SIGNS OF WEATHER.

" Whether clear or cloudy, a rosy sky at sunset presages fine weather; a red sky in the morning bad weather or much wind, perhaps rain; a gray sky in the morning, fine weather; a high dawn, wind; a low dawn, fair weather.* " Soft-looking or delicate clonds foretell fine weather, with moderate or light breezes; hard-edged, oily-looking clouds, wind. A dark, gloomy, blue sky is windy; but a light, bright blue sky indicates fine weather.

Generally the softer the clouds look, the less wind (but perhaps more rain) may be expected; and the harder, more "greasy," rolled, tutted, or ragged, the stronger the coming wind will prove. Also, a bright yellow sky at sunset presages wind; a pale yellow, wet; and thus, by the prevalence of red, yellow, or gray tints, the coming weather may be foretold, if aided by instruments, almost exactly. Small, inky-looking clouds foretell rain; light scud clouds driving across heavy masses show wind and rain ; but if alone, may indicate wind only.

" High upper clouds crossing the sun, moon, or stars in a direction different from that of the lower clouds, or the wind then felt below, foretell a change of wind.

" After fine clear weather, the first signs in the sky of a coming change are usually light streaks, curls, wisps, or mottled patches of * A high dawn is the break of day seen above clouds, instead of the horizon.

white distant clouds, which increase, and are followed by an overcasting of murky vapour that grows into cloudiness. This appearance, more or less oily or watery, as wind or rain will prevail, is an infallible sign.

" Light, delicate, quiet tints or colours, with soft, undefined forms of clouds, indicate or accompany fine weather; but gaudy or unusual hues, with hard, definitely-outlined clouds foretell rain, and probably strong wind.

" When sea-birds fly out early and far to seaward, moderate wind and fair weather may be expected. When they hang about the land, or over it, sometimes flying inland, expect a strong wind, with stormy weather.

As many creatures besides birds are affected by the approach of rain or wind, such indications should not be slighted by an observer who wishes to foresee weather.

" Remarkable clearness of atmosphere near the horizon; distant objects, such as hills, unusually visible; or raised (by refraction), and what is called ' a good hearing day,' may be mentioned among signs of wind, if not wet, to be expected.

" More than usual twinkling of the stars, indistinctness or apparent multiplication of the moon's horns, halos, ' wind dogs' (fragments or pieces of rainbows, sometimes called ' wind-galls'), seen on detached clouds, and the rainbow, are more or less significant of increasing wind, if not approaching rain, with or without wind.

" Lastly, the dryness or dampness of the air, and its temperature (for the season) should always be considered, with other indications of change, or continuance of wind and weather.

" On barometer-scales, the following contractions may be useful:— RISE FOR N. E.LY.

NW.-N.-E.

DRY OR LESS WIND.

EXCEPT WET FROM N.ED.

FALL FOR S.W.1Y.

SE.-S.-W.

WET OR MORE WIND.

EXCEPT.

WET FROM N.ED.

When the wind shifts against the sun, Trust it not, for back it will run.

First rise after very low Indicates a stronger blow.

Long foretold, long last; Short notice, soon past.".