Miscellaneous Intelligence. 435 



equal in 1842 and 1846. During the interval that elapsed between 

 transits of these similar phases in 1842 and 1846, the same number of 

 southwesterly waves passed overthe area — and from the whole it ap- 

 pears highly probable that we have not only ascertained another return 

 of the great symmetrical wave, (the sixth,) but have also detected the 

 return of at least three of the individual waves contributing to its pro- 

 duction. 3rd. The very precipitous fall of the barometer character- 

 izing the posterior slopes of the northwesterly systems, as developed 

 by the discussion of the observations of 1842, is fully confirmed : in 

 connexion with this, the decrease of oscillation from the northwest 

 towards the southeast is also strikingly developed, as on former oc- 

 casions. 



The author, in alluding to the area over which these observations 

 extend, remarked that the British Isles present a far too limited area for 

 the purposes of examining thoroughly these atmospheric movements ; 

 he observed that in the more extensive examination which the move- 

 ments of November, 1842, are now undergoing, there are four stations 

 at which the barometric changes are of an opposite character during 

 the first eight days of November,— namely, Christiania and St. Peters- 

 burgh in the north, and Paris and Geneva in the south. The curves at 

 St. Petersburgh and Geneva present the most decided opposition ; rising 

 at the one while falling at the other. The turning point in each case 

 occurred on the 5th. These opposite movements he conceived to be 

 occasioned by the opposite slopes of two waves passing from the south- 

 west > and that the half breadth of each wave extended at least from 

 Geneva to St. Petersburgh. Such being the extensive character of the 

 waves in question, in order to judge them in their totality it will be 

 absolutely necessary to enlarge the area of observation. The centre 

 of Europe is well dotted over with barometers, from which accurate 

 results may be obtained ; but even the British Isles, in connexion with 

 that portion of Europe now under observation, form but a small part of 

 the vast space over which the waves themselves extend. St. Peters- 

 burgh is an important northern station, from which we have most excel- 

 lent observations : but we require them also from Iceland, the northern 

 parts of Norway, Sweden and Lapland, and also from Archangel in 

 one direction, and from the southern parts of France, from Spain, I or- 

 tugal and the northern parts of Africa in the other; also from the Med- 

 iterranean they would be highly important. Observations stretching 

 from the most western point of Africa to the extreme north of Europe 

 would go far to determine the longitudinal directions of the north- 

 westerly systems of waves. In reporting the general progress of the 

 inquiry, Mr. Birt stated that we are now in possession of the materials 

 for examining the great symmetrical wave, not only in particular years 

 as 1842, 1845, and 1846, but also over the central parts of Lurope and 

 the dominion of the Russian empire, as far as Sitka, on the northwest 

 coast of America. He has combined observations extending from the 

 west coasts of Ireland and the Orkneys on the one hand, to at. eters- 

 burgh and Geneva on the other ; and he apprehends that the whole of 

 the barometric movements over this area, which occurred during the 

 first eight days of November, 1842, are fully explained by the transits 

 of two largeVaves on two sets of parallel beds of oppositely directed 



