Once a Week (magazine)/Series 1/Volume 8/Meteorology—its present condition
METEOROLOGY—ITS PRESENT CONDITION.
In these days of new theories we must not be astonished at the rise of new sciences. One or two of them, at least, are yearly born of hypothesis and experience. Social Science is still a babe in arms; Ethnology, Comparative Philology, and several more are hardly released from the nursery. Meteorology, however, is growing like a young giant. Many writers have dabbled in it from Aristotle to Lord Bacon; but from its very nature, composed as it is of numerous observations, time and opportunities of comparison were needed before it could be elevated to more than a piece of empiricism. Hear, however, Admiral FitzRoy’s cheering language. It is contained in the last Blue Book issued by the Meteorological Department of the Board of Trade, which we purpose to examine in this article. Speaking of the air currents of these latitudes, he says:
“Knowing these circumstances, and having accurate statical observations of these various currents at selected outlying stations—showing pressure (or tension), temperature, and relative dryness, with the direction and estimated horizontal force of wind at each place simultaneously, the dynamical consequences are already measured approximately on geometrical principles; and, judging by the past, there appears to be reasonable ground for expectation that soon meteorological dynamics will be subjected to mathematical analysis and accurate formulas.” This means, simply, that meteorology will soon rank among the exact sciences. The climate of any place in the world, even if no observations have been as yet taken there, can even now be approximately defined.
Many domestic philosophers of the past and present century have amused themselves in the spirit of White of Selbourne, by registering rainfall; but their statistics seldom had more than a local interest. Observations, however, are now taken officially at several home and colonial ports. All Her Majesty’s ships are required to register a large number of practical facts bearing on the weather. Not less than 5500 months of good meteorological observations have been collected from about 800 merchant vessels, and thus a large library of log-books and other statistical documents is now in existence at the Admiralty. The subtle agencies over which meteorology reigns have been tracked and seized upon with the utmost perseverance. The amount of fog is measured by the lighthouse-keepers round our shores. The direction of the wind is registered in many places by self-acting anemometers, and a few easy calculations show its force. The amount of dew is daily collected at our great observatories; the degrees of heat and cold carefully ascertained; the quantity of ozone in the atmosphere determined; electricity and magnetism duly taken into account. These statistics are the food of our youthful science. It grows apace when they are administered by such nursing fathers as Dové, Humboldt, and Herschel. Even Titans, however, must not be crammed, or unfortunate results will follow; and Meteorology has already been almost killed by kindness. The quantity of observations which have been made without any definite object in view, and with a vague hope that eventually they would be found useful, almost exceed the power of its digestive organs.
Meteorology, however, is most interesting considered as an applied science. In proportion as it is practical (or “fruitful,” to use the Baconian metaphor), it commands popular favour. The Meteorological Department of the Board of Trade has been most useful in promoting this desirable result. Seven years ago Mr. Cardwell experimentally organised it, and in the history of these few years lie the chief claims of meteorology—at all events on public grounds, to be practical. But it is in Admiral FitzRoy that the mythical personage, “the Clerk of the Weather,” has at length found “a local habitation and a name.” He arranges and works that system of “weather-forecasts,” as he calls them, which is so useful to mariners. Even plain men by glancing at the published weather reports, consulting their thermometers and barometers, and keeping an eye on the aspect of the heavens, may now with a little practice easily foretell the weather at least a day in advance, with every probability of being right. In many cases, however, violent storms can be predicted several days in advance. Here is a wide field for conjecture. The “Report” above mentioned relates that at a recent meeting of the shareholders of the Plymouth Docks, a deficiency in revenue was accounted for by the absence of vessels requiring the use of the graving docks for the purpose of repairing the damage done by storms. This may reasonably be attributed, in part, to their benefiting by the storm-signals. So as meteorology grows, we may speculate on hail and lightning risks being so much at a discount with farmers that they will not care to insure. Nay, those familiar articles, umbrellas and goloshes, may thus gradually lose their occupation, and even macintoshes have to retire into private life.
But it is on public grounds that applied meteorology is immeasurably more important. Saving of life and property at sea is far more to be thought of than saving a man from a wet coat. The possibility of giving telegraphic notice of storms formed part of the deliberations of the British Association at Aberdeen in September, 1859. The subject was brought home to every one’s thoughts in the next month by the loss of the Royal Charter. Accordingly the Board of Trade commenced telegraphic communication in September, 1860, and on February 5, 1861, the first cautionary or storm signals were made. The first published “forecasts” of weather were tried in August, 1861, and in another half-year the present system of forecasts two days in advance was established, and the full tables on which they depend sent regularly to several of the newspapers.
Such is a brief account of the rise of applied meteorology. Too much must not be expected of it at present. The storm warnings it gives are essentially tentative. They are general, and require correction by local instruments and observation of the skies. Even the satisfaction of knowing there is no bad weather impending is valuable as a negative gain. Remembering, too, that these storm warnings are only cautionary, that no sea-faring man is bound to go by them, but has time thus given him to make all snug for bad weather if he chooses to go out in spite of them, we think that these drum and cone signals seaside visitors must be familiar with, cannot but be valuable to our great marine commerce. As a matter of fact it is gratifying to hear that out of fifty-six circulars of inquiries respecting the system which Admiral FitzRoy addressed to the chief ports of the United Kingdom, seven expressed no decided opinion, forty-six were favourable, and only three decidedly averse to it.
All weather-wisdom depends upon the principle that Nature never gives false signals, that her laws are invariably true; we cannot interpret them, or we interpret them wrongly. Averages, statistics, observation, instruments, &c., are all helps to a surer interpretation. In proportion as our knowledge of Nature increases, and our instruments are better understood, so will meteorology extend her sway. Thus it has been proposed to give storm warnings to ships in the offing by means of coloured lights. This would go far to stop those calamities on a lee-shore which swell our wreck chart. Again, most of the British storms are cyclones: a zone of storm revolves round a comparatively smooth centre, and the whole storm passes on with a definite track,—generally in Great Britain from S.W. to N.E. Thus, while the Royal Charter, though a steamer, was smitten with the full fury of the great storm of October 25 and 26, 1859, a sailing vessel, differently handled a few miles off, rode it out in safety; while no further off than the west coast of Ireland fine weather and light winds prevailed. Now, Sir J. Herschel states that the most important meteorological information that could be given, would be telegraphic information of such a cyclone’s advance; and with the requisite lighthouse machinery, &c., this could be given.
It must not be forgotten, however, that the present system is expensive to the country. Salaries, printing, and telegraphy cost the Meteorological Department of the Board of Trade 2800l. in 1860; in 1861 it rose to 3700l.; while this financial year 1862-3 is estimated at 4600l. Significant figures are these that our Titan has not done growing.
In conclusion, we will add from the Report a few data to assist Paterfamilias in “forecasting” weather for his household. He must be scientific now; poor man, he is not even allowed that old fashioned belief of change in the weather at the moon’s quartering. Remorseless science assures him it is “a mere illusory deduction from coincidences, many of which must occur within a day or two of limits bounding only one week.” We may tell him, however, by way of consolation, that science has quite come round to his opinion that meteors are a sign of foul weather. By remembering a few simple rules, and inspecting the published reports, everyone may be his own weather prophet. A man who possesses a barometer and a thermometer, and knows how to read them, can beat all prophets out of the field. Change of weather is gradual, and great storms or changes are usually shown by falls of the barometer exceeding an inch, and by differences of temperature exceeding fifteen degrees. The more rapidly such changes occur, the more risk is there of severe weather. The normal height of the barometer in these latitudes is 29.24 to 30.00, though 27.45 has been registered in the Orkneys. A tenth of an inch an hour is a fall indicating a storm or very heavy rain.
The thermometer is also valuable for foretelling wind and weather. Shaded, and in the open air, when much higher than the following averages between eight and nine o’clock, a.m., it indicates southerly or westerly wind; when considerably lower the reverse. The table is calculated for Greenwich, but, allowing for differences of mean temperature, can of course be used elsewhere for weather prognostication.
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January
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37° |
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February
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39° |
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March
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31° |
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April
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46° |
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May
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53° |
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June
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59° |
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July
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62° |
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August
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61° |
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September
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57° |
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October
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50° |
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November
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43° |
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December
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39° |
M.