veru, in particular, near Newnham, and l60 miles from 

 Lundy, the head of the flood at spring-tides rises in 

 height like a wall, near nine feet high. Thu$ it pours on 

 for many miles, usually oversetting any vessels that lie in 

 its way. This head tide they call the Boar; it flows 

 here only two, and ebbs ten hours. 



But how shall we account for the ebbing and flowing 

 of Lay-well, near Tor bay 1 This ebbs and flows many 

 times in an hour. It usually performs its flux and re- 

 flux in a minutes' time. But it stands two or three mi- 

 nutes after the ebb : so that in the whole, it ebbs and 

 flows about sixteen times in an hour. 



14. Currents in the sea are either natural and gene- 

 ral, arising from the daily rotation of the earth on its 

 axis, or particular, or accidentally caused by the waters 

 being driven against promontories, or into gulphs and 

 straits, where wanting room to spread, they are driven 

 back, and so disturb the ordinary flux of the sea. 



The currents are so violent near the line, where the 

 motion of the earth is the greatest, that they carry ves- 

 sels swiftly from Africa to America, but prevent tkeir 

 returning the same way. So that they run as far as the 

 fortieth degree, to find a passage into Europe. 



In the straits of Gibraltar, which are about twenty 

 miles broad, the current almost always runs eastward* 

 And so it usually does in St. George's Channel. But 

 the. most violent sea is in the straits of Magellon, which 

 is owing to two contrary currents, which meet HI those 

 straits. 



Sometimes there is an under-current, contrary to that s 

 above. So it is in the Baltic sound. One of the king's 

 frigates being there, they went with their pinnace in the 

 mid-stream, and were carried violently by the current. 

 Soon after they sunk a basket with a large cannon-bul- 

 let to a certain depth of water. This checked the moti- 

 on of the boat. And when they sunk it lower the boat 

 was driven a head against the wind as well as the upper 

 current. And the lower the basket was let down, the 



