44 REPORT—1848. 
of 1 and 2 intersect in the neighbourhood of Geneva; if so, we have for 
determining the semi-am plitude of crest No. 2, the following data: — 
Semi-amplitude....The anterior trough being at Geneva. 
The crest at Belfast .......... 792 miles. 
Nov. 6. While the anterior slope of crest No. 2 is most strikingly deve- 
loped over Western Europe, extending from Belfast to Geneva, the posterior 
slope of the Scandinavian wave, which now transits St. Petersburgh, is also 
developed from that station to Alten; and between these slopes, and crossing 
them more or less at right angles, we have crest No. 1 still between 
Christiania and Alten, so that we have a considerable elevation of the baro- 
‘meter in Great Britain and Ireland, the extremity of the Scandinavian pe- 
ninsula, and at St. Petersburgh. On each side this ridge of pressure the 
‘barometer exhibits lower readings; at Geneva, 29°86; at Alten, 29°69; both 
-at the level of the sea. 
The area of greatest pressure has much the same direction as on the 5th, 
‘with this exception, the north-eastern extremity makes a greater progress 
‘towards the south-east than the south-western. This is precisely a conse- 
‘quence of the waves being situated as the observations indicate. The area 
‘of greatest pressure does not result from a single wave-crest, but is due to 
:at least three contemporaneous crests in Northern and Central Europe, two 
‘of these having the same direction, but one being in advance of the other, and 
‘the third crossing these nearly at right angles. As the advanced north-west 
‘wave passes off towards the south-east the pressure diminishes in the north- 
‘east, thus giving rise to the unequal motion of the two extremities of the 
‘area of greatest pressure. 
Noy. 7. The barometric movements over western Central Europe are very 
‘small; in Northern Europe they are greater. In the first area, Western 
‘Central Europe, the crest No. 2 is transiting; this crest thins off towards 
‘Northern Europe, and the Scandinavian wave considerably influences the 
‘barometer in this the northern area. Barometric falls in Northern Europe, 
including the Orkneys :— 
Phe Orineyat ig.ct5.«) siete ejeis, Wes Gee co -ojcanaee COR 
GRA, ABE aati AMG ats vias oto eins Haiole naw ema 
Sb.y Petersburgh sfeja,0 Sater seiner Gierqge iss woe aretny, SeO 
Baraat ca i siatoienh ol 'oslel ie aw ew wae oie 
While the barometric falls at St. Petersburgh and the Orkneys appear to 
‘have resulted from two different causes, two distinct posterior slopes, the 
‘fall at Alten appears to have been compounded of these two slopes, viz. 
‘that of the Scandinavian wave and that of crest No. 2. The area is thus 
‘divided into two sub-areas, Alten, Christiania and the Orkneys falling from 
crest No. 2, and St. Petersburgh from crest No. 1 and the Scandinavian wave. — 
During the operation of the causes just alluded to, by which the pressure — 
thas been diminished at Christiania and St. Petersburgh, these stations are — 
brought more to a level with Geneva from the approach of crest No. 3. At 
-Alten the barometer has been falling principally from the posterior slope of the — 
Scandinavian wave; a trough now transits Alten, but from the opposite 
‘curves at this station and Lougan it does not appear to be the posterior — 
‘trough of the Scandinavian wave, which most probably transited on the 9th; _ 
‘it is most likely to be a secondary trough, or rather minimum, produced by — 
the approach of crest No. 1, which probably transited this station on the 8th. — 
The following table exhibits the distribution of the crests and troughs on — 
‘this day :-- 
= 
