338 OUTLINES OF NATURAL PHILOSOPHY. 



the coast of Ireland. This wave soon after di- 

 vides itself into three ; one part passing up the 

 British Channel, another ranging along the west 

 side of Ireland and Scotland, and the third en- 

 tering the Irish Channel. The first of these flows 

 through the Channel at the rate of about 50 miles 

 an hour, so as to pass through the Straits of Do- 

 ver, and to reach the Nore about twelve at night. 

 The second, being in a more open sea, moves 

 with more rapidity ; by six it has reached the 

 north extremity of the Irish coast ; about nine it 

 has got to the Orkney Islands, and forms a ridge 

 or wave extending due north ; at twelve, the sum- 

 mit of the same wave extends from the coast of 

 Buchan eastward to the Naze of Norway ; and in 

 twelve hours more, it reaches the Nore, where it 

 meets the morning tide, that left the mouth of 

 the Channel only eight hours before. Thus these 

 two tides travel round Britain in about twenty- 

 eight hours, in which time the primitive tide has 

 gone round the whole circumference of the Earth, 

 and nearly 45 degrees more. YOUNG'S Lectures 

 on Natural Philosophy, vol. i. plate xxxviii, fig. 

 521. 



Thus 



