"STORM -warnings may be considered as the most immediate practical application of weather knowledge." Mr. EGBERT H. SCOTT, Director of the Meteorological Department, so commences the eighth chapter of the admirable work to which he has given the title we have placed at the head of this page, and we cannot more fitly introduce the subject than by quoting them, because they express so well a fact which it is most desirable to impress on the public, viz., that storm warnings are not the outcome of fanciful theories or of heaven-sent prophesying powers, but of knowledge—knowledge re- sulting from careful study and laboriously gathered information by many persons in many lands—knowledge of the kind which can be added to for the general good by a vast number of persons who are so placed by circumstances that, by a little trouble and care, they might continually assist in this great and useful work, but who at present fail to do so.

Mr. SCOTT'S work, while containing most interesting and valuable information for those well acquainted with the subject, also seems to aim at giving to those who have not had their attention particularly drawn to it cleai views of the principles on which the different meteorological offices act, how the information neces- sary is culled, how far it is short of what might be furnished were a more universal interest displayed, and what grounds there ' are for hoping for increased accuracy in | the warnings in the future.

I Mainly for the information of many I persons at our Life-boat stations person- ally concerned in the question, who may suffer any day for want of Storm Warn- ings, and who also have in many cases to give most useful information to the Me- teorological Office, we propose to lay before our readers a very brief synopsis of some parts of Mr. SCOTT'S work.

It will best suit our purpose to com- mence with the eighth chapter of his book, in which he has briefly traced the i rise into an acknowledged science of the study of meteorology, and as its outcome I the principle of issuing storm warnings, ] or, in other words, of prognosticating the j approach of storms. The first suggestion I of the electric telegraph as a method of | conveying intelligence of storms is due to Mr. EBDFIELD, an American, who shares with Gen. EBID the honour of having re- duced the "Law of Storms" to a science.

EEDFIELD'S paper was published in 1847.

Certain progress was made by the United States Government up to 1860, when their operations were closed for the time by the civil war.

In 1855 an organisation was created by the French Government, a great impetus I having been given to the study of the ! subject by the celebrated Balaclava storm | of November 14th, 1854, of which it was evident effectual notice might have been given had its earlier progress been noted, and warnings telegraphed to the more southern parts of Europe.

In England the idea of a general Euro- pean organisation was broached at the meeting of the British Association in 1859, and public attention was arrested by the loss of the Royal Charter a month later, from the fact that it seemed probable that had the information of the approach- ing storm (expected by many meteorologists) been telegraphed to headlands on the coast, the Royal Charter might have seen some warning and escaped.

In 1861 our Meteorological Department issued its first warnings, on principles devised by the late Admiral FitzRoy.

Since then many improvements have been effected, and vast additions have been made to our knowledge, but the leading features of FitzKRy's system characterise that in use to-day, though his plan of issuing forecasts three days in advance had to be abandoned, not being sufficiently justified by results. It is to be remarked, while on this part of the subject, that this country labours under considerable disadvantages for obtaining informa- tion of the' approach of storms to the British Islands. The majority of storms in these latitudes come from the west- ward ; in such cases the Signal Office at Washington, for instance, has the whole of America westward of it from which to receive information before the storm reaches the thriving cities and crowded harbours of the east coast, but telegrams sent from America to this country have proved of little value to us, because storms commonly change their character, or die out before they reach Europe, and our storms generally come to us from a more northerly direction. Again, while we may have had no direct warning of a gale approaching the Irish coast, the moment the tempest strikes the most westerly of our stations, all European coasts east of us know what to expect. Thus Ham- burg, for instance, which lies about south- east of our most advanced stations on the north-west of Ireland and Scotland, j has been kept so well advised by our Meteorological Department since 1867, that 72 per cent, of the warnings sent have been justified by gales following them, and in three cases only the storms have arrived before the telegrams. In fact, the stations in the British Islands which report to our office in London form a complete chain of sentinels for the North Sea and its eastern coasts in the direction of the approach of the great majority of storms, while they are too close at home to give nearly so effectual a warning to our own shores. It is manifest from this that one of our I requirements is a chain of stations away I to the west; but unfortunately there is no land in that direction till we come to Labrador, and the proposal of telegraph wires to the Azores, to the Faroe Islands, or to ships moored off in mid-Atlantic is at present, at least, impracticable.

Mr. SCOTT describes the present practice of Storm Warnings as a moderate advance on M. Le Terrier's plan proposed in 1860.

In a letter to Sir George Airy in that year, he says: "The ultimate result of the organisation which we are establishing should be to announce a storm as soon as it appears at any point in Europe, to follow it on its course by means of the telegraph, and to give timely notice of it to the coasts which it may reach." Bear- ing in mind what has been said as to the course of the majority of storms, it will be seen by a reference to the map of the coasts of Western Europe, attached hereto, and on which are indicated the principal meteorological stations in telegraphic com- munication with each other, at what a dieadvantage this country stands in re- spect of receiving warnings from the west, and what a valuable outpost it is to the rest of Europe. There are- certain conditions, however, by which at least meteorologists themselves are placed on their guard, and on which, to a limited ex- tent, they are able to act, as though they had certain information of the approach of the invader, and by the aid of the great stores of information of the ways and doings of storms now amassed make not only shrewd forecasts, but feel themselves justified in issuing warnings to the coasts; a course adopted, however, with extreme caution, for to use Mr. SCOTT'S words: " These circumstances, and other premo- nitions of a similar nature, are not of very frequent occurrence, and in general it is not until the storm is quite close at hand, and the barometer has begun to fall briskly at the outposts, that we feel our- selves justified in issuing a definite •warning." Such interesting and useful information is given at this point, as to these premo- nitions, that we endeavour, to give the substance of it.

Easterly winds on the northern side of westerly winds are a nearly sure sign of the approach of southerly winds, the precursors of a cyclonic area, and perhaps of a storm, which will probably affect the whole kingdom. If, for instance, a belt of country—say Scotland—reports an easterly wind sweeping over it, while England and the Channel feels the wind at West, south winds, and then a storm, will be pretty certain to be close at hand; while the ap- pearance of easterly winds on the southern side of westerly winds is not followed by any disturbance of a cyclonic character.

Of course there is a certain process of sound reasoning which arrives at this rule apart from mere accumulation of facts, but we cannot enter on that here.

" A rapid and unexpected rise of the barometer is often the precursor of a coming depression, so that whenever we see a sudden rise we may expect an equally sudden fall, and must be on the look out for the slightest tendency to give way." But it is alsp to be remembered, that the actual fall of the mercury on our own coasts must always be taken in connection with the change at dis- tant stations. Thus, in a remarkable storm, which occurred on the 29th No- vember,/ 1874, the warning was issued the day previously, not merely because of the fall of the barometer at our western stations, but because, at the same time, an increase in the rise of the barometer was occurring at Rochfort, while in the south of France the readings were seven-tenths of an inch higher than in the south of Ireland, and this showed that " pressure was banking up to the southward, and gradients were becoming steeper along the Channel coasts." But if the barometer falls simultaneously at our south-western stations and in the south of France, we have less to fear from westerly winds; while a rise of pressure over France, when it is already relatively high, leads to the expectation of a blow from the westward in this country; and so by a similar pro- cess of reasoning and observation, to a certain extent, we can anticipate bad weather from other quarters.

It will be of some interest if we reproduce the exact description of the particular storm in question.

Mr. SCOTT says:— " The earliest unmistakable signs of its ap- proach (fig. 1) were at 8 A.M., November 28, when Fig. 1.—November 2S, 1874.

8 A.M. Approaching depression.

a rapid fall of the barometer at Valencia, with the southerly wind, and the course of the isobar of 29-3 inches, show that there must be an area of lower readings at sea, outside the coast.

" Over the greater part of England the direc- tion of the wind is south-easterly ; a very general phenomenon on the approach of a serious storm, owing apparently to the in-draught of air to- wards the region of diminished pressure.

" The next chart, for 6 P.M. on the same day (fig. 2), shows the central isobar (of 29-0 inches) Fig. 2.—November 28, 1874.

6 P.M. Depression advancing.

over the south of Ireland, while the S.E. winds over England have veered to S.W., and the isobars, previously running nearly north and south, show a marked curvature. Even in Nor- way pressure has given way, the isobar of 29-8 inches having taken the place of that of 29-9 inches.

" During the night the storm made rapid pro- gress, and at 8 A.M. on the 29th (fig. 3) we have the Fig. 3.—November 29, 1874.

8 A.M. Centre over Wales.

centre of the storm lying near Holyhead, and the influence of the depression extending over the whole of western Europe." If now we compare Figs. 1 and 2, we see that the curve of 29 • 5 inches passed along the west coast of France at 8 A.M.

on the 28th, while at 6 P.M. there had been a rise of a tenth of an inch at | Kochefort. At the same time the reading | at Valencia had fallen 0 • 3 inch, and ac- ! cordingly the total difference between these two stations had increased about 0'4 inch.

Another important sign is the gradual in-draught of the air towards what will be the centre of the coming revolving tempest.

For instance, previous to the arrival of a cyclone on the west coast of Ireland, the wind is frequently south-east along the west coast of France, at a time when, as yet, the barometer gives no indications.

Disturbances of the sea, " ground- swells" and the like, are unreliable, although, as most of us know, set great store by on the part of old fishermen.

The fact is that unusual disturbances of the sea on our coasts are caused by storms blowing far off at sea, but only when the direction of the wind impels waves to- wards us; but it may well happen—does happen frequently—that though the centre of the storm is marching steadily towards us, the particular side of the cyclone nearest to us is bio wing "the waves from us, hence the full blast of the storm may reach us without any premonition on the part of the sea. In other cases the wind blows the disturbed sea before it, and gives warning; again, it commonly hap- pens that a great storm in the distance drives a heavy swell towards our shores, while nothing of the wind itself' ever reaches us.

Temperature of the air, on the other hand, is an invaluable aid, though the variations of the thermometer have not yet been subjected to strict rules in the manner the barometer has; but it is known that great variations of tempera- ture at adjacent stations are an indication of serious disturbance. On the 13th November, 1875, for instance, at 8 A.M., the thermometer at Stilly stood at 57°, and at Wick, in the north of Scotland, at 21°. On the following day, the 14th, heavy gale, accompanied by a high tide and extensive inundations on the south coast, and the banks of the Thames, caused great destruction.

There are other signs and other pro- cesses of reasoning; but enough has been said in this place to indicate, how- soever roughly, the kind of aid brought into play by the meteorologist, inde- pendently of, or even in the absence of, direct information of the approach of the j storm.

The first chapter of "Weather Charts and Storm Warnings" is devoted to a clear and elaborate explanation of the meanings of the different signs and ex- pressions of the daily Weather Report officially issued, and which, of course, we have no space to copy here. But one remark is well worthy of the attention of seafaring and coast people, in the habit of remarking and reporting on the weather.

The office in London, in lack of finding suitable reporters, is commonly obliged to employ persons employed in indoor oc- cupations to report to it. " It is obvious," says Mr. SCOTT, "that such a weather report as can be given by a clerk who simply runs out to look at the sky, just before filling up his despatch, cannot be of as much value as that of a man who has been in the open air watching the weather for an hour or so, or even for the better part of the day." Here is a case in which our sea-coast population, from among their numbers, could surely give the necessary aid if their attention was called to the necessity. Another defect felt is the infrequency of the reports, our office only being able to afford to pay for one telegram daily from most of its sta- tions, while that of Washington, for in- stance, receives three daily from each ' station. This is a matter of funds, and depends on the Government. i On Sunday, again, information is neither j received, nor warnings sent, the branch ' telegraph offices being closed for most of j the day. We are glad to learn, however, that since the beginning of December a Sunday service of weather telegrams and of warnings has been organised. It is simply a financial question as to whether or not this can be continued after the end of March next. Here again all depends on the Government.

Mr. SCOTT commences his chapter on winds with remarks on that one which, according to the popular adagp, is " good neither for man nor beast." We are reminded that, however dis- agreeable we may find the east wind in this country, this is not a universal law; for if we travel on the same parallel of latitude eastward to the Sea of Ochotsk, or westward to Labrador, we find in those regions the cold, bitter wind comes from the north-west, and the warmest from the south-east, the extreme coldness of the wind in either case being caused by its passage over large tracts of country bar- ren, dry, and frozen, where the mean tem- perature is lowest. Thus our cold east wind in winter flows over Northern Rus- sia, that of Labrador comes from the north- west and the vast frozen regions of the Hudson's Bay territory, and so on. Wind is cold and dry coming from a cold region, warm and moist from a warm one.

It has been commonly said of late years that all cold winds flow from the Poles to the Equator, and become the Trade winds as they approach the tropics, while warm winds flow from the Equator to the Poles, and become the Anti-trades; and although a body of air can hardly be proved to flow the whole way from the Equator to the Poles, or the reverse, it is a fact that over extensive areas " the wind does main- tain a constant direction for a consider- able period of time." The phenomena of the trade winds and monsoons are well known; but also over large tracts of Eu- rope and the North Atlantic in these lati- tudes the wind sometimes blows from the east or the west for weeks together, and these great channels or streams of wind flow in opposite directions side by side. " The dis- turbances which cause our storms appear to occur along the debatable regions be- tween two such currents, and when the currents change their beds, or the lines of demarcation between them alter their posi- tions, the storms and disturbances move with them." We have thus the idea presented to us of two great streams passing east and west, with the border line between them from time to time altering its latitude: further, we are informed that the direction and velocity of the air are regulated by the distribution of atmospherical pressure at the surface of the earth, and that pressure is indicated by the barometer. A principle •which lies at the foundation of modern weather knowledge is here enunciated.

It is called Buys Ballot's law:—• Stand with your lack to the wind, and the barometer will lie lower on your left hand than on your right.

In the southern hemisphere the words left and right must be transposed. This law is the extension to all cases of wind motion of the law of storms first announced by REDFIELD and REID for the hurricanes of the West Indies and elsewhere.

The best idea we can gain for practical purposes, regarding the winds which pass over the British Islands, is to suppose that "the air over the Atlantic Ocean, north of 40°, is constantly flowing from west to east like a gigantic river. If such a river be flowing rapidly, we often see on its surface small waves, each with its own eddies and circulations, which are carried on with the stream. If we could look at the upper surface of the atmosphere we should see much the same sort of con- ditions, except that what corresponds to the hollow of the wave would be a patch of defective pressure, while that which corresponds to the crest of the wave would be an area of excessive pressure." Air is a gas, and is more mobile there- fore than water, so that, wherever there is pressure from the atmosphere being piled up, there is an effort to resume perfect equilibrium; that effort causes winds and storms. Pressure or weight of air affects the barometer as we have seen, and here we have the connection between the barometer and the tempest.

Probably the most interesting chapter in the book is that on gradients. The word is borrowed from the engineers, who, in mea- suring an incline, use that word; if a slope rises regularly, for instance, 1 foot in height for every 60 in length, it is called a gra- dient of 1 in 60. The meteorologists take a gradient referred to a unit of the baro- metrical scale and miles of horizontal dis- tance. The gradients of our office are ex- pressed in hundreths of an inch of mercury —for every 60 nautical miles of distance.

If the difference of gradient is very great between two stations, there is reason to expect, in some shape or another, an im- mediate effort to recover the equilibrium: the steeper the gradient the more violent the wind that will ensue; as an instance of his meaning, Mr. SCOTT says, " The dis- tance from Perizance to Brest is 118 miles, a gradient of 7 represents a total differ- ence of barometers at the two stations of 0'13 inch, so that whenever a westerly gale is blowing at the entrance of the Channel, bearing in mind Buys Ballot's law, we may expect the barometer at Pen- zance to be at least 0 • 13 inch lower than at Brest; but the lower barometer will be shown at Brest when the wind is from the east. The steeper the gradient the stronger the wind. Instances are given of known storms illustrative of this principle; and, furthermore, it is asserted that no serious storm was ever felt in the United King- dom with less than an absolute difference between two stations of •£ inch of mer- cury.

Fig. 4, which is a reproduction of Fig. 3 on a large scale, " gives a good example of an area of low pressure, or a ' depression/ or a cyclonic disturbance, for the terms are used almost indiscriminately, developed as fully as it is usual to find them in western Europe.

"The direction and force of the wind are given by arrows, or by a circle if there is a calm.

" The direction is of course shown by the direction in which the arrow is flying.

" The force is indicated by differences in the symbols employed.

" Thus it will be seen that there is a FEBBUABY 1, 1877.] THE LIFE-BOAT.

very heavy gale at Kochefort from W.N.W., a heavy gale at Scarbro' from S.E., a fresh breeze at Aberdeen from E., a light breeze at Brussels from S.S.E., and a calm at Toulon.

" The lowest reading (28 • 55 inches) is at Holyhead; the highest (30 • 00 inches) at Corunna.

" The innermost isobar (28 • 6) embraces almost the whole of Wales. That for 28 • 8 is oval in shape, and covers nearly all shall find that they show a circulation round the centre of depression.

"In fact, the wind sweeps round the i central area of depression, against watch hands, and this is the invariable law in all cases of cyclonic disturbances in the Northern Hemisphere. The wind moves in a direction opposite to that of the hands of a watch, and its course is nearly parallel to the isobars." No very precise relation has yet been to- Fig. i.—3fm. 29, 8 A.M.

England, and the east and-north of Ire- land. That for 29-0 takes in a little of France and Belgium, and the greater part of Scotland.

" The isobar of 29 • 2 envelopes the whole of Scotland, but is not carried out over the Atlantic beyond the Orkneys on one side and the coast of Brittany on the other, and it is only dotted in, as being merely inferred, in the absence of obser- vations over the Bay of Biscay.

" If we now turn to the wind arrows we established between the steepness of the gradient, and the force of the wind; but a gradient 0 • 07 inch of the barometer per 60 miles " indicates the probability of as much wind as an ordinary yachtsman would like to meet." One of the expressions in common use, and appearing in the daily weather re- ports, is isobar, it is derived from two Greek words, meaning equal weight. An isobar is a line passing through those places where the barometrical pressure is equal.

The readings of barometers from differ- ent stations being different, a chart is constructed as soon as the telegrams are received, and lines drawn through the various places where the barometers read alike; the result is a series of curves ex- tending round one another with a common centre; that centre may show the highest barometer or the lowest, but the circles which environ it show the barometer in- creasing or decreasing in height in regular succession, though with the more or less steep gradients of which we have already spoken. If the centre shows the lowest barometer, the least atmospheric pres- sure is there, and we have before us evi- dence of a cyclonic system in the course of being set up; and if the centre read- ings are high, while the barometer reads lower as the circles widen, we have an anticyclonie. The cyclone generally means storm in a greater or less degree, and the anticyclone means lighter winds and fair weather. In the centre of either system it is calm.

While on the subject of barometers, we notice that the old notion that it was possible to place opposite certain heights of the barometer certain types of weather may be considered obsolete, and though it may often happen with a high barometer the weather is fine, and with a low baro- meter the reverse is experienced, they have no necessarily correlative bearing on each other. It is true that there is more chance of a strong wind when the baro- meter is low than when it is high, but this arises from the circumstance that " cyclonic areas are usually much smaller than anticyclonic, so that when the barometer is low there is a greater proba- bility of a steep gradient, from adjacent higher readings in the neighbourhood causing high winds, than when the baro- meter is high." But it sometimes happens that the barometer will remain below 29 inches, opposite which we find the words " stormy" printed, for two or more days, and yet no gale follows; the mere height of the barometer, therefore, or the words regarding the weather printed on the scale, taken by themselves, are of no value, as indications of the coming weather at the station where the observations are made.

There is one subject we must briefly allude to, which is fully gone into in one of the earlier chapters of the work we are quoting from—the veering and lacking of the wind. The wind is commonly said to veer when it changes from left to right with the sun, blowing first at S.E., for instance, then at S.W., then at N.W. If it changes in the reverse direction, e.g. from S.W. to S.E., it is said to back. Whether a wind backs or veers depends on the motion of the systems of circulation to which the wind belongs. The wind veers when the area of depression, or centre of the cyclone, passes (on its course from W. to E.) north of the observer, but it backs if that centre passes to the south of him; and here, again, the barometer, acting before the actual change of wind, affords hints as to the probable new direction of the storm.

Probably one of the most interesting topics in connection with this subject is the motion of storms. On this point all meteorologists are not agreed—that is to say, there is a certain variation in theory as to what the causes of motion are.

Certain facts, however, are admitted on all sides. Storms do pass onward over the earth's surface at the same time that the wind is whirling round their centres, and this much appears to have been recognised in America so early as 1747.

The direction of this " march of the storm" varies in different parts of the world. On the east coast of the United States it is from S.W. to N.E.; the West Indian hurricanes travel from E.S.E.

to W.N.W.; in the Indian Ocean the hurricanes travel first from E.N.E. to W.S.W., but both the West Indian and Indian Ocean hurricanes eventually turn off at a sharp angle and advance to the E. In the British Islands the path of the storm may be in any direction, but as a general rule it is from W. to E.; from E. to W. is very rare indeed. The rate of FEBRUARY 1, 1877.] THE LIFE-BOAT.

advance of a storm is of the highest im- portance to ascertain as soon as possible, but this can only be ascertained by tele- graphic reports from stations it has actually reached. All storms vary in rate, and the speed at which they advance on a given course is no criterion of the rate at which the air whirls round their centres. Some cyclones which have advanced the most slowly have been among the fiercest. The ordinary rate of travelling of a West Indian hurricane is from 10 to 15 or 20 miles a day at first, and subse- quently it moves forward faster. But in the British Islands, storms have travelled at the rate of 50 to 70 miles an hour; and this, again, adds to the diffi- culties of our Meteorological Department in sending timely warning. The course of the storm is sometimes affected in a very marked manner by the contour of the country it approaches. Sometimes a storm which has advanced on a steady course across the greater part of the Atlantic, on striking the high-cliffed coast of Kerry, has put about, as it were, and after standing out to sea, stood away N.

till finding the opening of Donegal Bay, has crossed Ireland from Ballyshannon to Dundalk, and off into the Irish Sea, where it sometimes rests awhile before passing on to the E. Professor JOHN PURSER gives as a simile the course of smoke-rings, which we may observe, when drifting before a current of air, turned out of their course by their approach to some projec- tion with which they do not actually come in contact.

When a chart of a large area is ex- amined it is found that the cyclones have frequently a tendency to tra'vel round the anticyclones, and although this motion is not easy to follow out over small areas, it is "from this mutual action of the areas of high and low pressure on each other that we gain some notion of the coasts which are likely to be visited by a storm, of the direction which that storm will take, and of the quarter whence the wind in that storm will blow the hardest." One of the later chapters of Mr. SCOTT'S book gives us a short account of the different theories advocated by certain leading meteorologists of different nations as to the " origin and motion of storms," which we recommend to the perusal of those who are able to procure the book itself; want of space prevents our follow- ing the subject farther; our effort in this paper has been to widen if possible the interest in, and to incite to the intelligent study of, a science of daily increasing importance, and we have selected from Mr. SCOTT'S work certain leading passages which we think cannot be uninteresting to those of our readers who have not the leisure to study solid works.