ON ATMOSPHERIC WAVES. 41. 
. It may probably assist our conception of the transit of this wave if the po- 
tion of the crest for each day is particularized as under :— 
Noy. 3. Crest passing Alten. This crest evidently possessed considerable 
breadth, for we find only a diminution of 0°317 inch pressure from Alten to 
‘St. Petersburgh, 740 miles; from St. Petersburgh to Lougan, 860 miles, the 
dip is very much greater, 1°134 inch above three times. 
_ Nov. 4. Crest between Alten and St. Petersburgh. In consequence of the 
broad crest these stations are nearly on a level, the dip from St. Petersburgh 
to Lougan still very considerable, 0°748 inch. A 
Nov. 5. St. Petersburgh, the highest point ; the crest not yet arrived ; dip 
from St. Petersburgh to Alten, 0°089 inch ; from St. Petersburgh to Lougan, 
-0°820 inch. chan : 
Nov. 6. The crest rapidly approaching St. Petersburgh, which it transits 
most probably this day ; the anterior slope still presents considerable steep- 
“ness; dip from St. Petersburgh to Lougan, 0-784 inch; Alten is only 0°518 
inch above Lougan. va 
_ Nov. 7. The crest has now clearly passed St. Petersburgh ; this station is 
slightly raised above Lougan, but the dip to Alten has become considerable, 
0°517 inch. i 
_ Nov. 8. The direction of the dip is reversed, being from Lougan to Alten 
increasing. - 
_ These phenomena are rendered very apparent to the eye in the diagram, 
fig. 2. bis 
§ "The great Scandinavian wave presents very distinctly at Alten the well- 
known characteristic of the north-westerly system of waves, namely, that of 
‘a considerable and precipitous fall as the posterior slope passes; this fall is 
only interrupted by the crest of wave No, 2 on the 5th. 
y Fig. 2. 
1842, Nov. Noy. 1842, 
31 inch 31 inch. 
99 inch, - - - «tee 29 inch. ' 
’ Alten. St. Petersburgh. Lougan. 
istribution of pressure on the line from Alten to Lougan, from Nov. 3, the epoch of the 
sit of the Scandinavian wave at Alten; to Nov. 9, the epoch of the transit of the crest 
ougan. Barometric altitudes half the natural scale. 
In addition to the determination of this large Scandinavian wave, with its 
ents and phases, the additional observations at Alten, Geneva and Lougan, 
ist us considerably in more distinctly defining and limiting the waves already 
ght to light by former discussions. The breadth of the anterior slope of 
est No. 1 (Report, 1846, p. 142) is found to extend beyond Christiania, but 
so far as Alten, and the rise from Christiania to Alten, of *36 inch on the 
of November, clearly indicates the posterior slope of a wave preceding 
t No.1. The anterior slope of crest No. 1 is also more distinctly 
nifested by the observations at St. Petersburgh and Geneva than by 
ose at Belfast and Christiania, the depression of St. Petersburgh below 
