According to the meteorological folk-lore, the weather of the summer season is indicated by the foliation of the oak and ash trees. If the oak comes first into leaf, the summer will be hot and dry, if the ash has the precedence it will be wet and cold. Looking over the observations of the budding of these two trees for half a century, I find that the weather-lore adage has been pretty correct. The ash was out before the oak a full month in the years 1816, ’17, ’21, ’23, ’28, ’29, ’30, ’38, ’40, ’45, ’50, and ’59; and the summer and autumn in these years were unfavourable. Again, the oak was out before the ash several weeks in the years 1818, ’19, ’20, ’22, ’24, ’25, ’26, ’27, ’33, ’34, ’35, ’36, ’37, ’42, ’46, ’54, ’68, and ’69; the summers during these years were dry and warm, and the harvests were abundant. One can never think of this weather prognostic from nature without recalling the Swallow Song of Tennyson’s “Princess”:—
“Why lingereth she to clothe her heart with love,
Delaying, as the tender ash delays
To clothe herself, when all the woods are green?”
On a muggy morning a sudden clearness in the south “drowns the ploughman.” And yet enough blue in the sky “tae mak’ a pair o’ breeks” cheers one with the assurance of coming dry and sunny weather. The low flying of the swallows betokens rain, as well as any unseasonable dancing of midges in the evening. Sore corns on the feet, and rheumatism in the joints, are direful precursors. The leaves are all a-tremble before the approach of thunder. But throughout this volume I have given many illustrations.
But one of the largest and most important practical problems of meteorology is to ascertain the course which storms follow, and the causes by which that course is determined, so that a forecast may thereby be made, not only of the certain approach of a storm, but the particular direction and force of the storm. The method of conducting this large inquiry most effectively was devised by the French astronomer, Le Verrier—the great aspirant, with our own Couch Adams, for the discovery of the planet Neptune. He began to carry this out in 1858 by the daily publication of weather data, followed by a synchronous weather map, which showed graphically for the morning of the day of publication the atmospheric pressure and the direction and force of the wind, together with tables of temperature, rainfall, cloud, and sea disturbances from a large number of places in all parts of Europe. It is from similar maps that forecasts of storms are still framed, and suitable warnings issued; and a mass of information is being collected by telegraph from sixty stations in the British Islands, &c., of the state of the weather at eight o’clock every morning, and analysed and arranged at the Meteorological Office in London for the evening’s forecasts over the different districts of the country. A juster knowledge is being now acquired of those great atmospheric movements, and other changes, which form the groundwork of weather-forecasting.
The Meteorological Office, Westminster (entirely distinct from the Royal Meteorological Society), is administered by a Council (Chairman, Sir R. Strachey; Scottish member, Dr. Buchan), selected by the Royal Society. It employs a staff of over forty. The chief departments relate to: (1) Ocean Meteorology, including the collection, tabulation, and discussion of meteorological data from British ships, the preparation of ocean weather charts, and the issue of meteorological instruments to the Royal Navy and Mercantile Marine; (2) Weather Telegraphy, including the reception of telegrams thrice a day from selected stations for the preparation of the daily reports and weather forecasts. Representatives of newspapers, &c., receive copies of the 11 A.M. forecast based on the 8 A.M. observations; and also of the 8.30 P.M. forecasts based on the observations received earlier in the day. In summer and autumn harvest forecasts are issued by telegraph to individuals who will defray the cost. The Office also collects climatological data from a number of voluntary and some subsidised stations. The “first order” stations include Valentia, Falmouth, Kew, and Aberdeen. These have self-recording instruments of high precision, giving a continuous record of the meteorological elements.
A Government Commission which sat last year, under the Rt. Hon. Sir Herbert Maxwell, Bart., have issued a Report, recommending a number of changes in the management and constitution of the Meteorological Office; and considerable modifications are not unlikely to take place in the near future. In his evidence before that Commission, the Chairman of the Council acknowledged that the great function of meteorologists is the collection of facts; but the interpretation of those collected facts, in a scientific manner, is still in a very immature condition. Dr. Buchan, in his evidence, confessed that forecasting by the Council is purely “by rule of thumb.” It is not possible to lay down hard and fast rules for forecasting.
With regard to the storm-warning telegrams, as a rule, the earliest trustworthy indication of the approach of a dangerous storm to the coasts of the British Isles precedes the storm by only a few hours. Delays are therefore very serious.
It is admitted by the best British meteorologists that the observations of the United States are better conducted, although the best instruments in the world are set and registered at Kew, in England. The work of weather forecasts and storm warnings is carried on with the highest degree of promptitude and efficiency at the Washington Central Office. This is because the work of predictions has been hitherto the chief work of the Office: the entire time of the observers, on whose telegraphic reports the forecasts are based, is controlled by the United States Weather Bureau; and the right of precedence in the use of wires is maintained.
Professor Brückner, of Berne, has devoted a lifetime to the comparatively new treatment of climatic oscillations, based upon observations made at 321 points on the earth’s surface, distributed as follows: Europe, 198; Asia, 39; N. America, 50; Cen. and S. America, 16; Australia, 12; Africa, 6. One of his conclusions is that an average time of about thirty-five years is found to intervene between one period of excess or deficiency of warmth and the next, accompanied by the opposite relative condition of moisture.
All are familiar with the hoisting of cone-warning as indication of a coming storm. This work is exceedingly important, especially for those connected with the sea by business or pleasure. On the known approach of a cyclone of dangerous intensity, special messages are sent from the London Meteorological Office, warning the coasts likely to be affected. When the cone is hoisted with its apex downwards, it means that strong south or south-west winds are to be looked for. When the cone is hoisted with its apex upwards, it indicates that strong winds from the north or north-east are expected. Of course they are merely useful precautions; but they are universally attended to by people on the sea-coast.