MR MILNE ON A REMARKABLE OSCILLATION OF THE SEA. 617 



(2.) On the 13th February 1756, at all the ports in the mouth of the Thames, 

 there were for two days, great irregularities in the tides. On the 13th, the tide 

 ebbed only 2^ feet for four hours after high water, when it flowed again for a few 

 minutes. It then ebbed, but so little, that at low water there was 7 feet of water 

 at Sheerness, which was 5 feet more than usual. In the morning, during the 

 flood, it had blown very hard from the south of west. In the afternoon, during 

 the ebb, the wind had abated, and veered to the NW. To the force and change 

 of wind, the phenomenon was generally attributed. * 



(3.) On the 17th or 18th July 1761, at 6 P.M., the sea at Whitby, both in 

 the harbour and on the open sea, rose and fell four times in a quarter of an hour, 

 to the height of nearly 2 feet each time. The sea was then calm. 2 



(4). On 28th July 1761, the sea was at various places in a state of oscillation, 

 continuing for several hours alternately flowing and ebbing. At Falmouth, Fawey, 

 Plymouth, and Penzance, this oscillation was observed about 10 A.M. ; there the 

 tide rose suddenly 6 feet. At Carrick, Dungarvon, and Waterford, in Ireland, 

 it was not observed till 4 P.M., and it continued there rising and falling till 9 



P.M. 3 



It is related, that the day was calm and very hot ; but that, in the evening, 

 the horizon was cloudy, with thunder and lightning. In the account given in the 

 London Philosophical Transactions, it is stated, that near Penzance the storm of 

 thunder and lightning came on about 7 h 30' P.M. ; that it came from the NW. ; 

 and that there Avas the fiercest flash of lightning, and loudest clap of thunder, 

 ever experienced. About 8 P.M. a church there was struck, and partly de- 

 molished. 



On the following day, there was in Yorkshire, about 6 P.M., a terrible storm 

 of thunder and lightning. 



(5.) On the 18th September 1763, the sea at Weymouth suddenly rose 10 

 feet, and as suddenly went back again. * 



(6.) On the llth February 1764, the tide in the Severn suddenly ebbed and 

 flowed. 5 



(7.) On the 5th September 1767, between 7 and 8 P.M., soon after high 

 water, the water in the Liffey at Dublin suddenly sunk 2 feet, and in a moment 

 after, rose above 4 feet, and immediately thereafter rose to its proper level. Much 

 about the same hour, it being low water at Ostend, the tide suddenly rose and 



1 London Philosophical Transactions, vol. xlix. p. 530. 



2 DODDSLEY'S Annual Register, vol. iv. p. 137; Gentleman's Magazine. 



3 DODDSLEY'S Annual Register, vol. vi. p. 99. 



4 DODDSLEY'S Annual Register, vol. iv. p. 142 ; Gentleman's Magazine ; London Philosophical 

 Transactions, vol. lii. p. 508. 



5 London Philosophical Transactions, vol. iv. p. 83 ; DODDSLEY'S Annual Register, vol. vii. 

 p. 50. 



VOL. XV. PART IV. 8 D 



