370 ON THE METEOROLOGY OF IRELAND. 



than on the eastern coast, the numbers denoting the relative fre- 

 quency being nearly as 5 to 1. The frequency of storms is nearly 

 the same in the northern and southern portions of the island. 



2. The direction of the wind, in all the cases enumerated, was 

 between S. and W. In about half of these cases the wind blew, 

 throughout, from the same point ; in half it veered from 4 to G 

 points of the compass, the veering being in the direction produced 

 by a cyclone moving from S. W. to N. E., and having the path of 

 its centre to the north of the island. 



3. The axis of the gale is in some cases transferred parallel to 

 itself, to the eastward. Remarkable instances of this movement 

 occur in the gales of January 12, 13, and December 20. 



4. The least barometric pressure occurs, in almost every instance, 

 in the north-western quarter of the island.* 



5. The locality of the highest wind sometimes coincides with that 

 of least pressure, and sometimes does not. In the latter case, the 

 axis of least pressure is generally to the westward of the axis of the 

 storm. 



6. On either side of the axis of a storm, the wind appears to 

 blow towards that line. A remarkable instance of this phenomenon 

 occurred in the storm of January l.f 



We are now in a position to consider the question, whether all 

 storms are cyclonic ? and if not, what proportion do rotatory storms 

 bear to the whole ? Of the greater storms which have occurred 

 since the commencement of these observations, the rotatory charac- 

 ter of five those of October 6, 1850, November 18, January 15, 

 1851, March 18, and September 29 has been completely established. 

 We have seen in this section, that the same character may be pre- 

 dicated, with great probability, of five more ; while there remain five 

 in which the wind has blown, throughout, in the same direction. 

 In fifteen months, accordingly, there have occurred fifteen storms, 

 of which two-thirds were cyclonic. As respects the remaining one- 

 third, the phenomena are characterized, not only by the absence of 

 any veering of the wind, but also by the fact, that the pressures 



* In one case only, the locality of least pressure shifted from the north-western to 

 the north-eastern extremity of the island. This is consistent with the supposition, that, 

 the storm in question was a cyclone, whose centre had a progressive motion eastward. 



t The conclusions numbered 3, 5, 6, have already been drawn by Mr. Espy, from 

 an examination of the storms in the United States in the early months of the votr 

 18-13. Fir at Report on Metioro'.ogy. 



