358 



ON THE METEOKOLOGY OF IRELAND. 



from the S. E. ; and at 3 A. M. on the 19th it appears to have 

 attained its maximum. At 6 A. M. the wind again abated ; and at 

 7 A. M. there was a calm. The minimum pressure took place at this 

 time, and amounted to 28170 inches. At 9 A. M. the wind rose 

 again from the N. N. W., but not with such force as before ; and 

 in the afternoon there was a strong gale again.* 



From these facts it is evident, that the centre of the vortex 

 passed nearly over Markree at 7 A. M., and over Armagh at ll h 30 m 

 A. M. At Donaghadee, which is nearly in the prolongation of the 

 line connecting the two former places, the wind ceased at 1 P. M., 

 and recommenced at 5 p. M. ; so that the vortex passed nearly cen- 

 trally over this station at about 3 p. M. From these data we learn 

 that the cyclone moved from W. S. W. to E. N. E. ; and that the 

 velocity of the progressive movement was then about 12 miles per 

 hour. 



The dimensions of the vortex may likewise be collected from 

 the same data. The interval between the commencement of the 

 storm, and the passage of the centre, at Armagh, was 16| hours ; 

 and, the velocity being 12 miles an hour, the radius of the vortex 



* The following are the extra observations at Markree above referred to. The 

 numbers in the column headed " Barometer," are the excesses above 28 inches : 



Date. 



Nov. 18. 



Nov. 20, 



