272 Mr. W. Brown on the Oscillations of the Barometer. 



Names of Places. 



Orkneys .. 

 Glasgow .. 



Belfast 



Armagh .. 



Shields 



Cork 



Bristol 



Plymouth 

 London .. 



Paris 



Christiania 



+•16 

 +•13 

 +•20 

 + 15 

 +•10 

 +•33 

 +•09 

 +•14 

 +•10 

 +•06 

 +•06 



+•07 



+•09 

 •00 



+•07 



+•10 

 + 13 



+ 11 

 + 15 



+•14 

 + 12 



+•11 

 -•10 



5. 



-•01 

 +•03 

 +•12 

 +•07 

 -•01 

 +•17 

 +•02 

 +•05 

 +•06 

 -11 

 -04 



-02 



-•06 

 -•01 



-07 



6. 



-02 



-•04 



+ •06 



•00 



-•02 



+•04 



+•08 



+•10 



•00 



+•02 

 •00 



-04 

 -•02 



-•06 



-02 



•00 



+ 01 



+•02 

 -•11 



The first very conspicuous atmospheric phenomenon is an 

 elevation of the barometer, which at Orkney reached the 

 highest point at the p.m. observation of the 4th, and advanced 

 towards south. Its maximum was in the north and north-west, 

 affording an excellent illustration of § 7 ; for on the 4th, the 

 day on which the principal rise took place, we find the col- 

 lision of the currents on the western and south-western side 

 of the chart : thus at the Irish ports and the Scilly islands the 

 wind was south-east, whilst in England and Scotland and at 

 Paris it was north-east. Hence at the Orkneys the barometer 

 stood at 30*54 and at Belfast 30*57, these places being situated 

 in the line of the meeting currents ; whilst at London, which, 

 so far as the observations go, was in the line of the north-east 

 current moving freely, the barometer reached an elevation of 

 only 30*19 ; the advance of the north wind and of the eleva- 

 tion of the barometer likewise accorded with each other, both 

 being from north to south. 



The observations of the 1st are particularly illustrative of 

 § 5 and § 8 ; in them the opposition of the southern current is 

 seen only in the extreme south, where it is blowing with some 

 strength, causing a fall of the barometer in the south, where 

 the north wind is blowing immediately in front of the south 

 wind (§ 5), and a slight rise in the north by the arrival of the 

 air removed from the south (§ 8). It might be thought that 

 the setting out of the currents in somewhat different directions 

 from the western part of England might give rise to this fall, 

 but it is evidently not so, because it decreases towards the lo- 

 cality where the current takes the easterly deflection. The 

 deflection of the southern current is also worthy of remark. 

 At the Scilly islands the south wind meeting a north-east 

 blows from the south-east, but at Paris meeting a north-west 

 it is south-west or west-south-west (§ 11). The cause of the 

 north wind being north-west in the north and eastern parts, 

 appears to be owing to a deficit of pressure in the east (the 

 barometer at Christiania being '39 inch below that at the 



