APPENDIX. 291 



very different times ; and that the high water of the northern zone 

 will have passed that meridian about three hours before the equato- 

 torial wave. Impulses derived from them might succeed one 

 another at an intermediate point, such as the Sandwich Islands. 

 Besides which, there is the tide of their own zone to be considered ; 

 in consequence of which alone it might be high water at about 6 : 

 thus these islands are so situated as to receive at least three tides — 

 one primary and two derivative — whose respective times of high water 

 are 1, 6, and 10, a succession which may well be supposed to neu- 

 tralise any ebb, and maintain the water thereabout above its natural 

 level, independent of tide. 



About the Strait of Magalhaens, and along the eastern coast of 

 Patagonia, there are very high tides ; apparently complicated, but 

 perhaps less so than is usually beheved. 



A powerful tide arrives at the Falklands, and at the east end of 

 Staten Land, at about 9 ; which is opposed by another powerful 

 tide arriving from the west. The union of these two accumulates 

 the water between Tierra del Fuego and the Falldands, and on the 

 east coast of Patagonia. 



Within the Strait of Magalhaens, westward of the Second Nar- 

 row, it is high water at about 4.40, and the tide rises six feet : 

 but eastward of the First Narrow it is high at 1.30, and the tide rises 

 forty feet. 



Now, as in one case the sea only rises three feet, and in the other 

 twenty, above its mean level, every one would expect to find a rush 

 of water through the Narrows, from the high sea to the low, and 

 such is the fact. From ten to four the water runs westward with 

 great velocity, and from four till ten it rushes eastward. During the 

 first interval, from ten to four, the eastern body of water, between 

 Tierra del Fuego and the Falldands, is above the mean level ; and 

 during the latter interval, from four till ten, it is below the mean 

 level — that which it would have if there were no tides. 



From 50° S. to near Blanco Bay in 40° S. the tide-wave certainly 

 travels along the coast to the north ; but this is a derivative from the 

 meeting of tides above-mentioned, combined with the primary tides 

 on the coast traversed. In this way principally may we account 

 for a high tide in one place on this coast, and a low one on another 

 (similarly situated, though differing in latitude) ; and, again, a high 

 tide at another place. During the twenty-four hours that the deri- 



