148 REPORT—1846. 
wards, the opposite to subsidence would take place; the depth of trough 
would decrease™ ~~ -~____—_ , and the oscillations to the south-east 
would also decrease. Such phenomena appear to be presented by the ob- 
servations from the 5th to the 10th of November 1842. 
November 10, 1842. 
Crest No. 2. 
S.W. N.E. 
Crest No. 3. 
N.W. SE, 
Max. London...... 29°64 
Shields... 9958 (Near crest No.8 
Belfast ...... 29°57 
Plymouth.... 29°48 
Bristol soi as 29°46 pe posterior slope, No. 3. 
ark co42 3024" 29°20 
Orkneys .... 29°39 
Christiania .. 29°24 
Slope-—Line of greatest diminution of pressure on posterior slope of 
Crest Now2. Londen to Cork (5. psi eeccd seats ne. oS "44. 
Altitude of anterior slope, Crest No. 3. Christiania to London.. *40. 
Altitude of posterior slope, Crest No. 3. Cork to Belfast........ "37. 
Currents.—Wind on N.E. side of Crest No. 3, N.W. 
se. DW 9% 5 3, S.E. 
* posterior slope of Crest No. 2, S.W. 
oS anterior slope of Crest No. 4, N.E. 
Trough succeeding Crest No. 2 now transits Christiania. 
The direction of the crest No. 3 is nearly identical with that of No. 1, 
which passed Great Britain and Ireland on the Ist. This appears to suggest 
that they were either successive crests of the same system of waves, or were 
succeeding waves produced by the same disturbing causes. The altitude of 
crest No.3 is about half an inch less than that of crest No.1; but between 
the transits of the two crests a wave from the N.W. with a deep posterior 
trough has passed the area, which has probably depressed crest No.3. The 
interval between the crests Nos. 1 and 3 is equal to nine days. 
It was noticed in the remarks on the 9th, that the great difference in the 
oscillation at the Orkneys and Paris most probably resulted from the sub- 
sidence of the crest as it progressed. The crest No.3 came from the S.W., 
so that a line from Plymouth to Christiania would cut it more or less trans- 
versely ; the ranges however are nearly the same at both stations. The crest 
which traversed England on the Ist arrived at Christiania on the 4th; at this 
time the barometer had commenced rising at Plymouth from the anterior 
slope of crest No. 2, and it continued rising until the 7th, when the crest 
passed. At Christiania the barometer had fallen from the posterior slope of 
crest No.2. It appears from a careful comparison and consideration of the 
barometric movements at Plymouth and Christiania, that crest No. 2 passed 
Christiania about a day earlier than it did Plymouth, that is, the longitudinal 
direction of the crest was such as to cause it to pass over Christiania while 
Plymouth was still under the anterior slope of the wave, the sections passing 
over Christiania and Plymouth being separate and distinct. The character 
of the passing wave is well-determined at both stations, the posterior slope 
\ Under anterior slope, No. 3. 
exhibiting a rapid and deep fall, which took place alike at Christiania and 7 
Plymouth. 
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