ON ATMOSPHERIC WAVES. 277 



(B 1) has been most satisfactorily traced, but the distance from Scilly to 

 Longstone Avas not long enough to exhibit the span and altitude*. 



Explanation of the Sections of Waves, Figs. 1, 2 and a, Plate XLIV. 



Fig- 1- — The curves in this figure are intended to exhibit the variations of 

 pressure from Scilly to Longstone ; the extent and form of the line selected 

 is shown below. The three blue curves, abc, give the approximate atmo- 

 spheric/or»i, the barometer descending. The three red curves, def the varia- 

 tions of form during the passage of wave B 1, and the curves ff h the form of 

 the posterior slope of the larger wave on which B 1 was superposed. See 

 note to (24.), Remarks on Atmospheric Waves. 



Fig. 2.— The curves in this figure represent the form of the atmosphere be- 

 tween Geneva and Brussels. They are projected from the reduced altitudes at 

 Geneva and Brussels, and altitudes taken from the models at two points, 01 and 

 02 ; 01 between Geneva and Brussels, and 02 in the same line beyond Brussels. 



Fig. 3.— The curves in this figure represent the form of the atmosphere 

 in a line from Brussels by Birmingham to Dublin, with two intermediate sta- 

 tions, as in fig. 2. 



Additional Remarks. 



iW 7^^^}^^^^^ °^ ^^^- d'scussion of the barometric observations of the 9th 

 and 10th of November 1842, has been to obtain, as nearly as possible, a clear 

 apprehension of the distribution of atmospheric pressure with its variations 

 over the area mcluded by the stations furnishing observations, previous to 

 undertaking an examination of the great symmetrical wave which traversed 

 Europe from the 11th to the 25th of the month. In the course of the exa- 

 mination, the sections for the epoch November 9.3 are the most complete- 

 and as but few of them have been given, it may be interesting to subjoin the 

 results obtained from an examination of the remaining sections, especially 

 as they are particularly illustrative of the wave A 1, which has already been 

 alluded to as traversing Europe on those days. 



^ MmiidJ*''Genfva ^"^^ ' ^'^^' ^*'"°'*''"^' ^"''""' ^«'"y' P^"«' Heligoland, 

 (2.) In this area, Longstone, Scilly and Brussels form a triangle inclosine 

 England. Longstone to Brussels will give a section of the distribution of 

 pressure on the eastern coasts of England ; Longstone to Scilly, the distribution 

 on the v^estern, and Scilly to Brussels on the southern ; Longstone, Birming- 

 Ham and St. Catherine's Point, the distribution nearly from north to south f! 

 Plo\ Vrv"'^?,^!'*^" ""l ^^^^^ sections, as given in the first sheet of sections, 

 riate al. v., vfi\X show that the most precipitous slope occurred on the eastern 

 shores of our island, and that this is characterized by a bulge (or most probably 

 a superposed wave) in the neighbourhood of Haisboro on a normal wave or a 

 permanent slope. The same result is obtained across the island from obser- 

 vations entirely distmct, as at Birmingham and St. Catherine's Point, and the 

 two sections are essentially similar, especially in the precipitous manner in 



inductdTe^fcom^f^thf ''''^°"-°^ *^' circumstances of the passages of these waves has 

 •09oTnch See r?n% V T'^^'^'T' *^f '^^ 'P'^'^ ""^ ^ ^ ^^^ 341 miles and its altitude 

 + i?^"- =*f (20.), Remarks on Atmospheric \¥aves. 



sections'in Plate xlv! ^°^''°'^ ^""^ ^'"^ '"^^''^^ '"^ ^^^'^ ^L"- '" °^^«^t° i^^^t'^te the 



