202 MR ALEX. BUCHAN ON THE STORMS OF WIND WHICH OCCURRED 



centre. It takes a direction nearly intermediate, approaching, however, more 

 nearly the direction and course of the circular curves than of the radii to the 

 centre. To this general rule none of the eleven storms any day offered an ex- 

 ception. When the centre of the storm was in a situation where observations 

 were made all round it, the following were the general directions as observed :— 



At p 



aces S. of the centre of least pressure, the wind was generally S.W 

 S.E. „ „ „ S. 



E. 



N.E. 



N. 

 N.W. 



W. 



s.w. 



S.E. 

 E. 



N.E. 



N. 



N.W. 



W. 



The greater the force of the wind at any place, the more nearly did it approxi- 

 mate to the directions here indicated. On those occasions when no observa- 

 tions were obtained from one or more of the sides of the storm, such observations 

 as were obtained followed the same rule. Hence the atmosphere on every occa- 

 sion rotated round the centre of the storm ; and it should be kept in mind that 

 this is no theoretical statement, but the result of observations faithfully put down 

 on maps. 



It will follow from this, that as the storms advanced to the eastward the general 

 veering of the wind at places lying north of the central path of the storm would 

 be from the N.E. by N. to W. ; and at places to the south of the centre, from the 

 N.E. by E. and S. to N.W. 



On referring to the chart of the 2d November (Plate XVI.), it will be seen 

 that the violence of the wind was greatest in the north of France, and south of 

 England and Ireland, where there were great differences in the pressure, as shown 

 by the crowding together of the isobarometric lines. On the other hand, it will 

 be seen that the wind was nowhere blowing a gale in North Britain, where the 

 pressure varied little for a great distance all round, as shown by the distance 

 between the isobarometric lines, even though the pressure there was absolutely 

 low. Again, on the 11th November (Plate XVIIL), the isobarometric lines were 

 far apart in Storm V. in the north, and the wind was nowhere strong within that 

 disturbed area ; whereas the lines were much crowded in Storm VI. round Ply- 

 mouth, and the wind was blowing strongly all round. This blowing of the wind 

 from a high to a low barometer, and with a force generally proportioned to the 

 differences of the pressure, would appear from these storms to be the most im- 

 portant law concerned in regulating the movement of the wind. As the wind 

 approached the centre of least pressure, its violence gradually abated, till, on reach- 

 ing the centre, a lull or calm prevailed. 



Calms and light winds also prevailed along the ridge of highest barometer, or 

 the region where the pressure was greatest, and on receding from which, on each 





