May 25, 1857.] PHYSICAL GEOGRAPHY. 415 



Consulting Mr. A. Keith Jolinston, of Edinburgh, who had 

 devoted many years to the accumulation of such data, Mr. Cleghorn 

 found that his view of the prevailing south-west wind was correct, 

 as respected all the region of the globe north of N. lat. 30° ; and 

 hence he is naturally disposed to generalize the application of facts 

 which are not only curious, but of value to the practical civil 

 engineer. 



An acquaintance with these data may, indeed, stimulate physical 

 geographers to look into the general eflects which have resulted 

 from the continuance during a very long period of the same great 

 dynamic force. In the mean time much inquiry seems to be called 

 for. Mr. Findlay, to whom we are so much indebted for a per- 

 spicuous collection of all observations on tides and currents, whilst 

 agreeing to the chief datum of Mr. Cleghorn, that the north-eastern 

 shore ought, in our latitudes, to be the deepest, and the south-west 

 shore the shallower, as due to the south-west wind governing the 

 direction of waves which frequently have their origin at a distance 

 of 1000 to 1800 miles from their effects, is not yet convinced of the 

 truth of the other portion of the inference of Mr. Cleghorn, that 

 the debris of the worn side is translated by a counter current 

 towards the south-west. He reminds me, in a letter to myself, that 

 the two circulating tidal systems, demonstrated by Dr. Whewell to 

 exist in the North Sea, seem to explain the drift of silt from the 

 extreme eastern shores of Britain to the Goodwin Sands and the 

 Flemish Banks ; whilst the debris abstracted from the south-west 

 coast finds its way to the heads of the flow-beds in Morecambe Bay 

 and the Straits of Dover, as shown by the tidal diagrams of Admiral 

 Beechey. 



As there is evidently conflicting evidence on this obscure part of 

 the subject, and as the " Flot du Fond " of M. Emy * has been much 

 disputed (M. Givry contending that wind affects the sea to no 

 greater a depth than 10 fathoms, whilst Captain M. A^'hite extends 

 that influence to 60 or 70 fathoms), we see how much additional 

 observation is required before we can definitely judge the question 

 with precision. If, by the examination of many other localities, 

 the views of Mr. Cleghorn should be sustained, the generalization 

 will be essentially serviceable in its practical application, and we 

 may then be able to define the origin and progress of many large 

 collections of drifted and alluvial matter, whether accumulated in 



* Du Mouvement des Eaux, &c. Par le Colonel A. 11, Emy. Paris, 1831. 



2l2 



