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The mean pressure in Great Britain is higher by about two-tenths of an inch in summer than in winter, but the highest readings seem always to occur in winter.
CYCLONIC (NORMAL) DISTURBANCES PRECEDING HIGH PRESSURE ANTI-CYCLONIC DISTURBANCES ACCOMPANYING IT.
During the first week of January, 1882, the weather experienced in the British Isles was the normal winter weather. The atmospheric disturbances which passed over Great Britain came up as usual from the South of West, and passed away to the North of East. They were also cyclonic in form, i.e., the central area was one of low pressure, with isobars of higher pressure surrounding it, increasing as they extended outwards from the central area. The course of the wind round the area of disturbance was also the true, or normal direction, being Westerly on the Southern side, and Easterly on the Northern side of the area.
During that time, however, an anti-cyclonic system of disturbance was forming in central Europe, and travelling up in a direction from S.E. to N.W.
The central area was one of high pressure, and the isobars surrounding it represented barometric readings decreasing as they receded from the central area of high pressure. The wind also circulated round in this system of disturbance in the opposite direction to that which it takes when the central area is one of low pressure; i.e., the wind was Easterly on the Southern side, and Westerly on the Northern side of this anti-cyclonic disturbance.
By the aid of twelve diagrams (copies of the Synchronous Weather Charts of Western Europe, showing the isobaric lines, wind direction and force, etc., at six p.m., which are published daily in the Times), the isobaric lines, and corresponding wind directions on twelve days between the 9th and 23rd of January, were shown.
It was thus pointed out that on the 9th of January normal cyclonic atmospheric disturbances prevailed over Western Europe, the N.W edge of the anti-cyclone being at the same time observed impinging on the Southern portion of the cyclonic movement. At this time the centre of the anti-cyclonic movement was over the Western part of Germany.
On the 11th January, the anti-cyclonic movement was spreading to the Northward, with its central area nearly stationary. The curves of the isobaric lines were deflected on the N.E side, owing to the proximity of a cyclonic disturbance, the centre of which was over the Gulf of Bothnia, and on the Western side, owing to another cyclonic disturbance making up to the Westward of Ireland.
From the 11th to 16th January the central area of high pressure remained nearly stationary over Northern Germany, the N.E. of France, and Belgium. The curves of the isobaric lines in the west of Ireland were on some occasions slightly deflected, marking the impingement of cyclonic disturbances travelling up from the S.Wa
On the 17th, the central area of high pressure was over the North of France, and was progressing slowly Westward; and on the 18th it was over the South of England, the highest readings having been attained on this day.
From the 19th to the 22nd, the central area of high pressure remained nearly stationary, though the barometer was falling steadily.
At six p.m. on the 20th, the reading was 30.7 inches, and on the 22nd it was 30.5 inches in the area of highest pressure, which still remained stationary over the South of England.
WEATHER DURING THE CONTINUANCE OF HIGH PRESSURE.
The weather over the whole of Western Europe during
this period was very settled; the winds were light, and blowing very steadily in the anti-cyclonic direction, the whole system seeming to stand like a stationary mass, against the western side of which cyclonic systems of unsettled weather working up from the South-westward impinged occasionally, and passed away to the Northward, skirting its Northwestern edge.
The weather in England, generally speaking, during the same period was dull, damp, and foggy, but without rain.
NOTE ON OBSERVATIONS SUBSEQUENT TO THE READING OF THE PAPER.
The above remarks brought the history of this abnormal weather up to the date on which the paper was read. As similar weather continued for some weeks afterwards, making the event even more noteworthy, the subjoined notes are added.
On the 22nd January, the barometer was falling slightly, and after falling to 30.5 inches, it commenced to rise again on the 23rd, and continued to read above 30.5 inches till the 28th January; during all this time the character of the atmospheric movements being distinctly anti-cyclonic. On the 29th and 30th, a cyclonic disturbance occupied the Northern portion of Western Europe, the anti-cyclonic movement still prevailing over the Southern portion of the area of observation. There was a threatening of bad weather, though none was experienced. These changes had been accompanied by a slight fall of pressure, but on the 31st the barometer rose again, and continued high, the weather being moderate and fine until the 12th and 13th February, on which days a cyclonic disturbance, accompanied by a gale of short duration, and a temporary diminution of pressure, passed over the north of Ireland, and Scotland. On the 14th of February the barometer was again rising, and con
tinued to do so, the atmospheric movements being of a decidedly anti-cyclonic character, and the weather very moderate until the 19th February, when the barometer again attained a reading of 30.8 inches. This pressure was maintained until the 22nd, when the barometer commenced to fall steadily, and by the 27th February, the anti-cyclonic system of disturbance had been replaced by an ordinary and normal cyclonic movement, accompanied by a gale of wind, unsettled weather, and a correspondingly low barometer. This seemed to be the final break up of the abnormal weather, and was succeeded by the usual unsettled weather to be expected in winter.
It will thus be seen that from the 11th January till the 26th February, a period of more than six weeks in the depth of winter, there was in Western Europe a continuance of quite abnormally moderate weather, accompanied by a very unusually high barometer, the only break being for a couple of days, viz., 12th and 13th February. On the other hand, it has been ascertained from ships' reports that very heavy weather was experienced in the North Atlantic at various times during those six weeks, and that these disturbances extended as far to the Eastward as the West of Ireland in some instances.
The Rev. S. FLETCHER WILLIAMS read a paper on Popular Misconceptions of Darwinism."*
EIGHTH ORDINARY MEETING.
ROYAL INSTITUTION, February 6th, 1882.
EDWARD DAVIES, F.C.S., F.I.C., PRESIDENT, in the
Mr. Charles Birchall and Professor Bradley, M.A., University College, were elected Ordinary Members.
* See page 133.
The Rev. H. H. HIGGINS exhibited some specimens of Lepidoptera brought from Queensland, and presented to the Museum by Mr. Reginald Cholmondeley. One of the specimens was a large Moth, Xylocanthà Staceyi, not previously brought to this country; and said to be so violent in habits and disposition that, except when bred in confinement, the specimens of it known to collectors are mere wrecks.
Mr. E. DAVIES exhibited a new form of electrical accumulator, discovered by Mr. Henry Sutton, of Ballarat, Victoria. It consists of a copper cell filled with an acid solution of sulphate of copper. In this is immersed a plate of amalgamated lead, kept from coming in contact with the copper. On connecting the accumulator with a source of electricity, either a battery or a dynamo-electric machine, the sulphate of copper is decomposed, copper is deposited on the copper cell, and the lead plate is coated with peroxide of lead. When the liquid becomes colourless, the cell is fully charged. With a cell six inches square and two inches wide, a thin platinum wire was heated to whiteness, and finally fused. A small Rhumkorff's coil was also worked by means of the cell. The cell is much smaller than a Faure or Planté cell of the same power. It is very constant, and is freely put at the disposal of science students by the inventor.
Mr. RICHARD STEEL read a paper on "Mental Science in its Quantitative Relations.”*
NINTH ORDINARY MEETING.
ROYAL INSTITUTION, February 20th, 1882.
EDWARD DAVIES, F.C.S., F.I.C., PRESIDENT, in the Chair.
Messrs. Hugh Hunter and J. B. Hughes were elected Ordinary Members.
* See page 193.