Abbildungen der Seite
PDF
EPUB

THE BAROMETER FAITHFUL AND CORRECT,

219

Extraordinary observations on this storm were made at Greenwich every quarter of an hour, for two whole days, and the barometer carefully noted ; bad we a similar production from the north and from the south, we should have the most beautiful and surprising illustration of all the three barometers acting in the most perfect accordance as to time, and each and all answering to the minutest quantity, and the wind being as obedient to the slightest variations of pressure, or resistance, as the most delicate mechanism we know. The zeal of future meteorologists will, I hope, supply this demonstration. The value of the Greenwich observations is impaired by the negligence of others, and the magnificent patronage was not seconded by any co-operation, and, from the apathy and indifference of the public, were discontinued.

The Rev. C. Clouston, in his letter of 4th February, 1843, accompanying the delineation he most kindly favoured me with, says, “ You will observe we had not the storm that was so destructive in England on 13th and 14th. The barometer was uncommonly low, and the sky threatened a storm.” Now here is an important fact. The barometer at Orkney was 28.56 to 28:51, and a light air from eastward, and nothing whatever accompanied the low barometer at Orkney, and consequently the barometer might be deemed useless and in fault, whereas, in England, the barometer being 28:46, a violent storm prevailed. Here is a very strong case and accusation against the barometer, and no abstract reasoning could clear it up. The circumstantial evidence

220 GALE AT GREENWICH---QUIESCENCE AT ORKNEY.

is so very strong and perfectly true. But, behold, the beauty and the power of comparative meteorology, and the whole truth and not a part. Everything appears contradictory, but look at the delineation. The Orkney barometer was higher by one-tenth of an inch than the Greenwich one; the powerful and strong wind at Greenwich, of 25 lbs. pressure on the square foot, could not blow into the Orkney area, because it was met by a greater and resisting force, although small in amount, yet quite sufficient to turn the scale and give the preponderance to the pressure from the northward. Orkney, as it were, laid in the very trough of the depression, but just on the verge or boundary of the northern pressure, and the extreme point of the southern depression. It lay, therefore, peaceful and quiet, nearly in the centre of the balance, or equilibrium, of two opposing currents; and it is worthy of particular notice how delicately and gently the barometer was raised, both at Orkney and London, by the gradual advance of the northern current, whose fierce impetuosity was checked by the gradually retreating power of the great S.W. current, which kept the northern one at bay, and only allowed it to advance by gentle steps. I cannot possibly conceive a finer illustration of the atmospheric actions, nor any more perfect demonstration of the correctness and infallibility of the barometer. It is impossible for it to err ; but our interpretations, alas ! how lax; and how wide a departure from the truth of nature do they exhibit.

The extreme depression of the barometer at London

ORKNEY OBSERVATIONS IN PHILOSOPHICAL MAGAZINE. 221

and Orkney at the same time, and yet with such different results and states of the weather, and their simultaneous and rapid rise of nine-tenths of an inch in twenty-four hours, running up side by side of each other, and mounting up so far above the depression of the previous days, are strikingly exhibited in the delineation, and which might be overlooked in the mere mass of figures as so elaborately given in the “ Philosophical Magazine,” March, 1843, conducted by Sir David Brewster, Richard Taylor, etc. To that work the public are amazingly indebted for the continued publication of the meteorological observations from Chiswick and Orkney, and from them I have derived the most valuable facts. And those who may wish to avail themselves of the Orkney observations will find them contributed to that work by the Reverend C. Clouston, whose zeal and fidelity I cannot sufficiently appreciate.

It would neither be safe nor prudent for me to have overstepped the bounds by giving more illustrations, else a large body of facts might be elucidated by a more extensive system of delineation.

But I am depressed by the expense, which, although small and moderate, is yet relatively great. For the little one I have prefixed, for its elegant manipulation I am indebted to the ability and talent of Messrs. Day and Son, Lithographers, Lincoln's Inn Fields, and am obliged for their undertaking so small an affair. If no one else admires it, I do, as a neat display of a most useful art.

Without a combination and union with the Orkney

222 THE BAROMETER THE BALANCE OF THE FIRMAMENT.

delineation, it would be difficult to convey precise ideas of the actions of the barometer and its wonderful indications. It is the key of most of the atmospheric states, and almost unlocks the vestibule of the firmament. The more it is contemplated the more it is appreciated, and it is the great teacher of meteorology; it is the foundation and basis thereof; it is a noble instrument, because it is the model of perfection and of truth; an unerring balance which weighs the atmospheric column of whatever height it may be, whether forty-eight or fifty miles, more or less. Although its weight is 14.7 lbs., or upwards of one hundred thousand grains, yet the mercurial column of 30 inches poises it, and turns to a grain difference in the weight of the superincumbent massbecause the mercurial column is not a cubic inch, and but a slender thread.

REMARKS ON THE STORM OF JANUARY 14, 1843.

( By Mr. Glaisher, Greenwich Observations,page 266.) The most remarkable meteorological phenomenon that has happened since the establishment of the magnetical and meteorological department of the Observatory is, beyond question, the extraordinarily low reading of the barometer during this storm. The commencement of the storm was almost simultaneous over England, Scotland, and the eastern coast of Ireland, and the remarkable depression of the barometer was general over a great part of Europe. On the morning of the 13th, the readings of the barometer

GLAISHER ON THE STORM OF JAN. 14, 1843.

223

began to decrease rapidly, and the wind began to blow. About 8 A.M. two vivid flashes of lightning and long peals of thunder, at an interval of 20 seconds. During the thunder the fifth-ball electrometer was not affected, and the gold leaf of the dry-pile electrometer was inclined slightly to the magnetic pile, but the needle of the galvanometer oscillated from 30° to the division 35° towards A. At 8h. 45m. A.M., the reading of the barometer had sunk below 28-3, and the rapid decrease of per

hour was checked. It, however, continued decreasing, and at 23 minutes past noon the minimum reading took place, being 28.096, a reading lower than has been registered at the Observatory since 1821, December 24th, at 5 A.M., when its reading was 27.89 as registered in the “ Greenwich Observations."

[ocr errors]

the reading was

1783
1809
1821
1824
1843

March 6th
December 17th
December 24th
November 23rd
January 13th

38.22 28.20 27.89 28.37 28.09

All the lowest readings, except that of 1821, occurred at or about noon. The barometer was very minutely observed, and in the gusts the oscillations of the mercury amounted to .05. The wind was strongest at the minimum reading, and the heaviest gusts preceded the minimum. The loss of life and property was great.

From Lloyd's books it appears 180 vessels were wrecked, 453 persons lost, and a total loss of property of £825,000. The wind was S.W., and in most places

a

« ZurückWeiter »