JOU 



AJL 



NATURAL PHILOSOPHY, CHElMISTRY, 



THE ARTS. 



JULY, 1806. 



ARTICLE I. 



Letter from a Correspondent, enquiring the Cause tohy a Swell 

 of the Sea is sometimes observed to precede a Storm from 

 the same quarter. With some observations by the Editor. 



To Mr. NICHOLSON. 



SIR, 



Hehton, Cornti^aU, 

 June 4, 1806. 



AT frequently happens on this coast that a heavy swell of the ^n heavy swell 

 . . , J . , , .. , often arrives on 



sea arrives from the westward, without any perceptible cause, tije Cornish 



Avhich is followed by a gale of wind or storm from the same coast, which is 

 1 r 1 T 1 1 11 ,. followed by a 



quarter many hours afterwards. I have observed the same fact storm. 



©n other coasts ; and I believe the phenomenon is very general- 

 ly known and admitted. It is not difficult to form a notion, 

 that an expanded surfa(ie of water, undulating in a certain di- 

 rection, may communicate a progressive motion to the air 

 above it ; but in all the theories relating to winds and waves, 

 it has constantly, as far as my knowledge extends, been assert- 

 ed that the waves are caused by the winds, and not the winds 

 hy the waves. We are also told by writers on meteorology, 

 Vol. XIV.— July, 1806. B b that 



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