210 Dr. Rigby's Observations on Waterspouts. 



their common focus, lines drawn from this focus to their points 

 of contact with the variable line drawn as above, contain a 

 constant angle." 



Rowlestown, Swords, Co. Dublin, 

 June 27, 1844. 



XXXVI. Observations on Waterspouts. 

 By Edward Rigby, M.D., F.L.S. 



To the Editors of the Philosophical Magazine and Journal. 

 Gentlemen, 

 TOURING my passage from Ostend to London, on the 

 ■*^ morning of the 20th of July, at about an hour before 

 sunrise, I had an opportunity of witnessing a meteorological 

 phaenomenon, viz. a waterspout, which is rarely met with in 

 these latitudes. The vessel lay on her usual course (about 

 W.N.W.), Ostend being about fifteen miles in an opposite 

 direction, the wind, a slight breeze, being dead ahead. 



A dense mass of clouds had been forming in the north-east- 

 ern portion of the horizon, and from the rapid manner in which 

 it increased, and from its course not corresponding with that 

 of the wind as we then had it, 1 was induced to observe to the 

 officer on deck that a thunder-storm was approaching. A 

 smart flash immediately afterwards confirmed my suspicions; 

 and as the northern extremity of the dark bank of heavy clouds 

 gradually lifted from the horizon, and its place was occupied 

 by a streak of dull red misty light, it was evident that torrents 

 of rain were pouring down from its middle and southern por- 

 tions. 



When at about the distance of 1|^ or 2 miles from us the 

 mate directed my attention to a funnel-shaped pillar of cloud, 

 which depended from the mass above apparently to within a 

 short distance from the surface of the sea, and was peculiarly 

 conspicuous from crossing the streak of dusky red light to 

 which I have just alluded. Its form was much contorted, and 

 varied in its direction every moment, not so much from the 

 whole mass moving continuously, as from its seeming suddenly 

 to disappear at one spot, and instantly to assume a different 

 form and direction close by. A dense haze, like smoke, rose 

 from the surface of the water in an oblique direction towards 

 the depending portion of the cloud, but the distance was too 

 great and the deck of the steamer too low to enable me to as- 

 certain whether the water was in the state of whirling foam at 

 this part as has usually been described. After continuing for 

 about a minute, its connexion with the water below appeared 

 to cease, and the depending portion of cloud diminished con- 



