THE weather in the British Islands forces itself so much on our attention, and is naturally such a constant topic of dis- cussion, that papers on the subject, especially when written by any one having access to the records of the Royal Meteorological Society, must, or certainly ought to. be of considerable interest. In the Quarterly Journal of this useful Society (Vol. XXVIII., No. 126, July 1902) may be found an article which should specially appeal to the readers of the Life-boat Journal. It is entitled, " The Prevalence of Gales on the Coast of the British Islands during the 30 Years, 1871-1900," and is written by Mr. Frederick J. Brodie, F.R.Met.Soc.

A perusal of this instructive article will well repay those interested in the subject—a subject which in the nature of things can never become hackneyed.

Most people lay some claim to be weather-wise, more particularly concern- ing the neighbourhood in which they live, and they read the well-known signs which indicate changes of weather— such as, some hill has a cloud cap on it, some coast line is particularly clear, strange - shaped clouds appear in a particular quarter, or a hundred and one other such phenomena—and dilate on them with an omniscient air; but they seldom care to go beyond these visual signs, and do not trouble much to inquire into the causes which produce these effects. Perhaps this is not to be wondered at, for the scientific study of meteorology is of comparatively recent date, and there is not always either the literature or the necessary instruments available for carrying out such inquiries.

Most people content themselves with looking in the newspaper at the forecast of the weather for the particular place they are in, and heaping abuse on the Meteorological Office if the forecast does not justify itself to the letter. Probably there is only a very small percentage of the population which really understands the interesting weather-charts issued daily by the Meteorological Society; the article referred to will, if read, consider- ably enlighten those who do not.

The present Meteorological Society dates back only to the year 1867, when the Council took over the Meteorological Department of the Board of Trade, which had been established in 1854.

Before that there apparently was no organised attempt made to deal with the subject in a manner worthy of the nation. Papers such as the one referred to above cannot fail to impress on the reader the value of the Society. Such a mass of tabulated detail from which conclusions are drawn speak for them- selves of the care and method in which the work is carried out. The writer tells us that— Prior to 1876 the record of gales com- prised, firstly, extracts from the automatic records of the various anemometers in con- nection with the Meteorological Office: secondly, the data supplied by the Telegraphic Reporting Stations; and thirdly, those furnished by a number of voluntary observers.

In 1876 these details were supplemented by information extracted from the logs of several Lighthouses and Lightships, the documents by a gale force 8 (Beaufort scale), or with a nominal velocity of 40 miles an hour, and he has included in his list those gales " in which such forces and velocities were general over at least a limited portion of the United Kingdom," and rejected those which were reported only in a few isolated places. Force 10 (Beaufort scale), velocity 60 miles an hour, has been taken as a " severe gale," and of such local occurrences as whirlwinds and tornadoes no notice has been made.

Among the general results it will be seen that in this country there is an average (over the 30 years) of 48-5 gales per year, of which 10-6 are severe or partially so.

'Fig. 1.—Total Number of Gales in each Year, 1871-1900.

being kindly lent for the purpose by the authorities of the Trinity House, the Scottish Meteorological Society, the Board of Irish Lights, and the Mersey Docks and Harbour Board. After the year 1889 the information from the latter sources was largely increased, while the reports from voluntary observers were no longer used. Owing to these changes and additions there has been throughout the period a gradual improvement in the value of the information employed, but for the bulk of the time.the stations of various kinds have been so well distributed that it has been quite impossible for a gale of any consequence to spring up on our coasts without a record of it appearing in the annual list.

And what is the definition of a gale ? Mr. Brodie explains that the Meteoro- logical Office has always considered a storm warning to be justified if followed Mr. Brodie shows in the diagram (Fig. 1) the total number of gales in each year, the continuous curve signifying the gales of all kinds, and the dotted curve the severe gales. The average number for 30 years is shown by the horizontal dotted line.

It is interesting to compare the two curves, from which it will be seen that in a year in which there are a great number of gales it by no means follows that the number of severe gales is proportionately great.

With regard to the value of the observations, the writer states, " A period of 30 years is far too short to yield any reliable evidence as to the existence of periodicity in the matter of stormy weather. Assuming that the features (in the diagram) are permanent and not merely accidental, there may perhaps be said to be some indication of a storm cycle recurring every 15 to 17 years." And "if there is any significance at all in these features we should now be entering upon a period of comparatively calm weather." It is certain]/ to be hoped that there is some significance in these features ! A similar diagram is used to show the mean monthly prevalence of gales (Fig. 2). This cannot fail to interest great falling-off in the number of gales, but in March the tendency for stormy weather increases in a somewhat remarkable way, the average number of gales in that month being 5'9, as against only 5'5 in February. After March the conditions rapidly improve, the curve of monthly values showing a brisk drop in April, and a more gradual fall to the summer minimum. The curve giving the monthly prevalence of severe or partially severe gales is very similar to the curve of gales of all kinds. Severe gales are most numerous in January, but the decline which takes place in February is arrested in March, the number in these two months being precisely similar. Between the months of April and August severe gales are rare, and in Gales of all kinds shewn thus •——i Severe & Partially Severe Gales sh&wnthus •' •• Fig. 2.—Mean Monthly Prevalence of Gales.

those who reside on our coasts; so very much must depend on the particular sort of weather to be expected in the various months.

From an examination of Fig. 2 we see, without any surprise, that June and July are the quietest months, the average number of gales in the former month being rather smaller than in the latter. With the advance of August the tendency for stormy weather rapidly increases, the curve showing a brisk rise until October, and a somewhat less rapid rise towards the end of the year. The stormiest month of all is January, with an average of 7-4 gales, 2 of which are general, and 2 severe or partially severe. In February there is a July they may be said to be non-existent.

The stormiest month in the entire 30-year period was January 1890. The total number of gales of all kinds in that month was, it is true, slightly smaller than in January 1894, in March 1897, or in the Novembers of 1882 and 1888. Of the 12 gales which occurred, however, in January 1890 no fewer than 7 were general, and of these 3 were severe and 3 partially severe. In addition to these, there was 1 partially severe gale in the West and North only, and 1 in the West and South, so that out of the total of 12 gales no fewer than 8 were either severe or partially so.

It is also pointed out that the average number of gales in the winter half-year (October to March) and in the summer half (April to September) is 37 • 6 and 10'6 respectively. Then as to the four seasons, it appears that the average number of gales is as follows :— Summer (June to August) ... 3 Spring (March to May) .... 10 Autumn (September to November) 15 Winter (December to February) . 20 Following these interesting details, the writer of the paper goes into the subject of " the Prevalence of Gales by Five-Day Means," " the Daily Prevalence of Gales,"' illustrated by diagrams, also "Long Periods of Quiet Weather," "Direction of Wind in Gales," " Velocity of Wind in Gales and Barometric Gradients in Severe Gales." With regard to this latter subject some very valuable information is given, which is of material aid in understand- ing the meteorological charts, and the position and distance of the isobars shown on them; in fact, so interesting is the subject that it is best to quote Mr. Brodie's remarks in extenso:— Barometric Gradients in Severe Gales.

The strength of the wind depends, as is well known, upon the steepness of the baro- metric gradient, or in other words, of the slope that is supposed to exist in the atmosphere between a place in which) the barometer is relatively high and a place in which it is at the same time relatively low.

The relation between these two elements varies, however, to such an extent that it is quite impossible to say that, with a given gradient, the wind will necessarily blow with a given degree of strength. Much depends, it is certain, upon the direction in which the gradient lies, the wind being usually much stronger with an easterly than with a westerly gradient of the same degree of steep- ness. Something may also be attributed to the conformation of the country over which the wind has to pass, a steep gradient over a hilly surface being usually accompanied by a lighter wind than exists with a similar gradient over a plain, where the flow of air has little to impede it. Prom an examination of more than 300 cases I am inclined to say that it is quite possible for a severe gale to blow with any gradient exceeding 0'25 in. per 100 geographical miles.

The examination in question has comprised a careful measurement of the steepest gradient existing during each of the severe and partially severe gales of the 30-year period. For this purpose I have used the daily weather charts prepared in the Meteorological Office. These charts are drawn only thrice daily, viz., for 8 A.M., 2 P.M., and 6 P.M., and it is therefore highly probable that in some cases a steeper gradient may have existed during a gale than anything shown at those fixed hours. With regard to one storm this was certainly the case. In order to obtain a representation of the distribution of pressure existing at the time when the barometer in these islands fell to the lowest point on record, I drew specially a weather chart for 9 P.M., and incidentally succeeded in finding a gradient steeper than anything yielded by the maps drawn for the usual hours of observation. The case in question occurred at 9 P.M. on January 26th, 1884, when the barometric gradient over the South-west of Scotland, the North Channel, and the extreme North of Ireland amounted to no less than 0'7 inch per 100 geographical miles.

Gases in which the barometric gradient was as steep as 0-6 inch per 100 miles occurred on the following dates and in the following localities:— 1874. October 21st, 8 A.M. Scotland and the adjacent parts of the North Sea.

1880. November 26th, 8 A.M. West and North of Ireland.

1881. October 14th, 2 P.M. South of Scotland and the extreme North of England.

1886. December 8th, 8 A.M. West of Ireland.

1890. January 19th, 8 A.M. North of Ireland.

1893. December 8th, 8 A.M. and 2 P.M.

Scotland and the North of Ireland.

1894. December 22nd, 8 A.M. Extreme North of England.

1900. December 20th, 6 P.M. West of Ireland.

These oases occurred without exception during the prevalence of general and severe gales and over some part of our Western and Northern coasts. Numerous instances in which the barometric gradient was as steep as 0-5 inch per 100 miles were observed in the same districts, but I have not found more than three cases in which such a gradient existed over the south-eastern portions of the kingdom or their immediate neighbourhood.

One of these occurred during the violent easterly gale and snowstorm of January 18th, 1881, and was measured over the midland and a portion of our southern counties; this was apparently the steepest easterly gradient experienced during the whole 30 years.

Another case occurred on December 8th at 8 A.M., when a gradient of 0-5 inch per 100 miles existed over a considerable portion of England and Ireland. The third instance was observed at 6 P.M. on December 26th of the same year, when a deep cyclonic system moved eastwards along the Channel and occasioned heavy snowstorms in the South of England; the very steep gradient of 0-5 inch was measured in this case over the eastern parts of the Channel and the north-east of France.

The steepest gradient observed in any of the summer months, June to August, was one of 0'35 inch per 100 miles, which'occurred at 6 P.M. on August 3rd, 1900, over the western and central parts of England. During the progress of this storm the wind attained a mean hourly velocity (true) of 50 miles at Fleetwood, of 45 miles at Kingstown, and of 44 miles at Holyhead, the force by Beaufort's scale being estimated by several observers as 10. In four other cases a gradient of 0-3 inch per 100 miles was observed in connection with summer gales, one of the most important instances occurring over the North of Scotland on June 25th, 1890. In this case a mean hourly velocity of 54 miles was reached at Swanbister in the Orkneys, and an estimated force of 11 at Wick, the gale (which blew from the westward) being attended by serious damage to the fishing fleets and considerable loss of life.

After touching on "The Movements of Important Storm Systems," " Rate of Movement," and "Regions traversed by the Centres of Important Storm Systems," Mr. Brodie concludes his article by giving a short description of some of the notable gales in the period under discussion, which includes such well-known storms (especially remem- bered by those who have to do with Life - boats) as the following :— January 18th, 1881; October 14th, 1881 ; January 26th-27th, 1884 ; December 8th-9th, 1886; November 17th, 1893 ; December 8th, 1893 ; and December 22nd, 1894.