THE THAMES. 107 



sometimes, and at Anapolis in Nova Scotia, to so mnch as 

 120 feet! Wind will also accelerate or retard both the 

 speed and height of the tides. London receives a much 

 greater tide than its due, for the tidal-wave being interrupted 

 by Ireland and England, rolls up the western coast (taking 

 a northerly direction) with such force as to swing round the 

 Shetlands and all down the eastern coast of Great Britain. 

 The direct Atlantic wave also, when split by our island, rolls 

 along the south coast from Land's-End to Dover, rushes 

 through the " Straits," and meets the backward wave which 

 has been travelling round by Scotland (as before mentioned), 



RIVEB, THAMES. 



the two then pour into the Thames and give an otherwise 

 quiet river a high and useful tide ; so that London receives 

 two tides, the southern one nearly 10 hours after Cornwall, 

 and the roundabout one not till nearly 23 hours after it 

 first reaches England. 



The waters are the great highway throughout the whole 

 world, and what an easy transit it has formed to those 

 nations sufficiently civilised to require a further knowledge 

 of the world, and thence procure for themselves luxuries 

 not obtainable at home at the same time, spreading civili- 

 sation wherever they go ! 



If the oceans, instead of forming one great concourse of 

 waters, had existed in the form of inland seas or great lakes, 

 the great chains of mountains, deserts, and uninhabited 

 tracts of earth, would, in some cases, have formed impassable 

 barriers, whilst in other parts civilisation would have been 



