460 The Rev. H. Lloyd on the Meteorology of Ireland. 



Sept. 30, 9 p. M. — General southerly current. Centre of vortex to the west 

 of the island ; least pressure on west coast. Greatest velocity of wind (on 

 west coast) — 45 feet per second. 



Oct. 1, 9 A. M. — Centre of vortex over the island, between Kilrush and 

 Courtown. Absolute minimum of pressure (= 28-838) equally distant from 

 Dublin, Courtown, and Dunmore. Northern stations beginning to be afiected 

 by vortex. Greatest velocity of wind (north-east) = 50 feet per second. 



Oct. 1, 9 p.m. — Centre north of Portrush. Absolute minimum of pressure 

 (= 28-853) at Portrush ; increase of pressure = 0-09 inch. At Donaghadee a 

 sudden shift of tlio wind from S. S. E. to W. took place at 4"- 30'"- p. m. 



Oct. 4, 5. — Distinct cyclone moving from "W". S.W. to E. N. E., and passing 

 over (or near) the northern extremity of the island. (Plate x. Figs. 4, 5, 6.) 

 Mean velocity of wind = 35 feet per second. General electrical disturbance. 



Oct. 4, 9 A. M. — General current from S.W. ; centre of vortex north-west of 

 island. Greatest velocity of wind (on west coast) = 45 feet per second. 



Oct. 4 9 P. M. — Centre close to northern extremity of the island. Abso- 

 lute minimum of pressure (=29-182) at Portrush; increase of pressure = O'll 

 inch. Greatest velocity of wind (north-west) = 55 feet per second. 



Oct. 5, 9 A. M.^Centre north of the island; least pressure at Portrush. 

 Greatest velocity of wind (north) = 60 feet per second. 



From the facts above stated, we may draw the following general con- 

 clusions : — 



1. The occurrence of cyclonic movements in the atmosphere is not infre- 

 quent in Ireland, and may be traced even in the case of moderate winds. 



2. The rotatory movement is invariably in the same direction, namely, that 

 opposite to the diurnal movement of the sun in azimuth. 



3. This rotation is always accompanied by a considerable disturbance of 

 barometric equilibrium, which is greater in proportion to the velocity of the 

 rotatory movement, the pressure being a minimum at the centre of the vortex, 

 and increasing regularly with the distance from that point. 



4. The place of greatest velocity appears to have no very definite relation 

 to that of the centre of the vortex, sometimes nearly coinciding with it, and 



