520 



was limited to the roofs of the houses, the hail having fallen 

 perpendicularly. The amount of the rain and melted hail re- 

 gistered there was 1*7 inches in 35 minutes. 



" Further information is wanting also to enable us to de- 

 termine exactly the progressive movement of the centre of the 

 vortex. We are informed by the newspapers that a storm 

 similar to that which visited Dublin, although not so severe, 

 took place at Mullingar, about an hour and a half previously. 

 If this be the same storm, the direction of the progressive 

 movement must have been nearly from west to east, and its 

 velocity about thirty miles an hour. This direction accords 

 with that given by the observed limits of the storm on the 

 northern and southern sides of the city ; but it seems to have 

 been modified, at the surface of the earth, by the lower cur- 

 rent. The velocity of the rotatory movement was, of course, 

 vastly greater than that of the progressive ; but we have no 

 direct measure of its amount. 



" The damage done in Dublin has been principally in the 

 destruction of glass caused by the hail ; but many chimneys 

 have been thrown down, and many roofs dismantled, by the 

 gale. The estimated amount of the loss sustained, as ascer- 

 tained by the Metropolitan Police, is £27,800. Many houses 

 were struck by the lightning ; but, happily, there was no loss 

 of life from that cause. 



" There seemed to have been a disturbance of electrical 

 equilibrium, accompanied by rain, in many remote parts of 

 Ireland on the same day." 



Mr. Hogan communicated the following additional facts 

 relative to the same phenomenon : 



" In tracing the history of the remarkable hurricane of 

 the 18th inst., we must distinguish between the direction of 

 the wind where it was raging, and the prevailing current of 

 air by which it was borne along from place to place. The 



