The Rev. II. Lloyd on the Meteorology of Ireland. 4G9 



28-689, when lowest. Tlie lowest pressure increased from that point in the 

 south-easterly direction, being 28'972 at Dunmore. 



At Markree the wind shifted from S. S. E. to S. S. W. at the time of 

 greatest depression. The same phenomenon took place at Armagh and Portrush, 

 although not with such precision ; the change of direction at the former station 

 being from S. S. E. to S., and at the latter from S. E. to S. No similar change 

 occurred at the southern stations. 



It should be observed, that the foregoing phenomena are not necessarily to 

 be ascribed to the transit of a rectilinear wave. They are all consistent with 

 the effects of a cyclone, coming from the S. or S. W., the track of its centre 

 lying to the west of the island. 



June 21, 22. — The changes of the direction and of the pressure of the wind, 

 on this day, are manifestly the effects of a cyclonic movement, the centre of 

 the vortex sweeping round the north coast of Ireland, in a somewhat curvi- 

 linear path, from west to east. It has not been included in the former series, 

 the force of the wind having been below the limit thei'e adopted. At 9 A. m. 

 of the 21st, the centre of the vortex was off the north-west coast, to the west of 

 Killybegs. At 9 p. m. of the same day, it had arrived to the north of Port- 

 rush ; and at 9 a. m. of tlie 22ud, it was to the north-east of Donaghadee. 



The veering of the wind was, on the average, about 90"; its duration was 

 very different at the different stations, being shortest for those near the path of 

 the centre of the vortex, and longest for those remote. The wind, which was 

 very light throughout, fell about the time of veering at most of the stations. 



The descent and subsequent rise of the barometer were regular, and 

 the minimum well-defined. The time of least pressure coincided at all the sta- 

 tions, very nearly, with the middle of the time of veering of the wind ; it was 

 earliest on the western coast, and latest on the eastern, the epoch of its occur- 

 rence being between 12 and 1 p. m. at Markree and Cahirciveen, and between 

 5 p. M. and 6 p. m. at Dublin and Courtown. The barometric depression was 

 small, the mean pressure at the epoch of minimum being 29'74. 



Humidity of the Am. 

 The following Tables give the results of the psychrometrical observations. 

 Table xxvi. contains the monthly means of the temperatures of evaporation at 



3p2 



