150. . REPORT—1846. 
The progressive motion of the two posterior slopes is very discernible. 
Crest No. 3 has passed the Orkneys and arrived at Christiania seven days 
after crest No. 1 passed that station. We found an interval between the 
crests as they passed the central parts of England of nine days. Most pro- 
bably a discussion of observations at shorter intervals and more numerous 
stations, especially to the north-east of Christiania, would explain the dis- 
crepancy. The difference in level is very much greater than that which cha- 
racterized the transits of the crests over the centre of England, but in the 
interval between the crests passing England and Sweden, the deep trough of 
crest No. 2 has advanced, which must very considerably have depressed the 
crest at Christiania, as compared with the English stations ; indeed so great 
was the depressing influence of the wave, crest No. 2, that no rise is recorded 
as crest No. 3 passed Plymouth. 
Crest No. 2 is situated considerably to the south-east of Paris, so that its 
progress is not perceptible on the area; but that of its posterior slope is very 
clear. On the 9th, the deep posterior trough of this wave passed the Orkneys 
with a depression of 28°80 ; (bearing in mind thet its direction was S.W.—N.E.) 
another section passed Christiania on the 10th, 29°24; and a third passed 
Plymouth on the 11th, 29°12. 
Symmetrical Wave.—On this day the great symmetrical wave commenced 
at London; the position of this station was nearly similar under both slopes, 
November 12, 1842. 
Crest No. 3. 
N.W.———_———-S..E.. 
Crest No. 5. 
N.W.—— S.E. 
Christiania ...... 29:20 
Orkneys .......- 29:10 >Under posterior slope, No. 3. 
Mint. a Shields.)-ee sere 29:07 
Trough. 
Belfast: ee rehet 29:21 
Cork, .: 29°31 
Sa 5 age es Under anterior slope, No. 5. 
Panis: awisen sae 29°43 
Max. Plymouth ...... 29°46 
Slopes.—Lines of greatest diminution of pressure. — 
On posterior slope of Crest No. 3. Christiania to Shields.. 13 
On anterior slope of Crest No. 5. Plymouth to Shields.... +39 
Currents.—Wind on S.W. side of trough, N.W. 
A few stations exhibit a S.W. wind on the posterior slope of Crest No. 2. 
The receding posterior slope of crest No 3, the intervening trough, and 
the approaching anterior slope of crest No. 5, are brought fully into view 
this day ; the wind also is in close accordance with the transit of these waves. 
The wave (crest No.3) appears to be much smaller than that of No. 1; the 
interval between the crests, as passing the centre of England, was found to 
be nine days; the epoch of the passage of the intervening trough occurred 
on November 7 ; interval between the troughs five days, taking the last in- 
terval as the amplitude in time of the wave; it is clearly much smaller than 
the preceding. 
Symmetrical Wave-——London is situated under and rising from the ante- — 
rior slope of wave No. 5. 
