14 



Mr. 11. H. Scott on the Connexion 



[June 17, 



In order to trace out this remarkable succession of occurrences, it was 

 resolved to examine all the cases in which the polar and equatorial cur- 

 rents made their appearance at the surface of the ground within the area 

 of the British Islands, and to record the phases of weather which ensued. 

 As these currents flow in opposite directions, it is evident that they must 

 move in chanuels approximative^ parallel to each other, so that there are 

 only two cases to be examined. 



I. The polar current flows in a latitude higher than the equatorial 

 current. 



II. The polar current flows in a latitude lower than the equatorial 

 current. 



The daily weather reports for a period of 27 months have been ex- 

 amined, and the result has been that 27 instances of case I. and 30 of 

 case II. have been discovered. 



These instances are all enumerated in two tables, which are herewith 

 submitted*. 



In accordance with the relation between the motion of the wind and the 

 distribution of atmospherical pressure which has been laid clown by Prof. 

 Buys Ballot, viz. that barometrical readings are lower on the left-hand 

 side of a current of air than on the right, we should expect to find that in 

 case I. there would be a relative barometrical minimum, and in case II. a 

 relative barometrical maximum between the currents. This supposition is 

 found to be abundantly confirmed by the observations. 



As regards the weather subsequently experienced, Mr. Meldrum states 

 that when the two currents, the N.W. monsoon and S.E. trade, are noticed 

 simultaneously over the Indian Ocean, the channel of the latter lying on 

 the southern edge of that of the former, i.e. in a latitude higher than it, 

 the barometer between them is low and falling. Ultimately the reduction 

 of pressure becomes greater at one point than at the others, and a centre 

 of barometrical depression is formed, resulting eventually in a cyclone. 



In the instances which form the subject of the present paper, we have 

 not been able to trace the actual genesis of a storm within the limits of 

 our area of observation. Most of our storms come on us from the Atlantic, 

 and are apparently not formed, in the immediate district from which our 

 reports are derived. The result of the investigation appears, however, to 

 show that whereas the conditions of case I. are indicative of considerable 

 atmospherical disturbance, those of case II. seem to show that winds will 

 probably be light for some days. 



Case I. The polar current flows in a latitude higher than the equatorial 

 current. 



In other words, easterly winds prevail in the north, westerly in the 

 south. Northerly and southerly winds are nearly entirely absent. 



Twenty- seven instances have been noticed of these conditions, and they 



* The Tables are necessarily so condensed that they would hardly be intelligible if 

 printed with the paper. 



