408 THE PHYSICAL GEOGRAPHY OF THE SEA. 



in groups near certain latitudes, tlie variable character of all the 

 currents of tlie sea — now fast, now slow (§ 401), now running this 

 way, then that — all of which may be taken as so many signs 

 of the tremendous throes which occur in the bosom of the ocean. 

 Sometimes the sea recedes from the shore, as if to gather strength 

 for a great rush against its barriers, as it did when it fled back 

 to join with the earthquake and overwhelm Callao in 1746, and 

 again Lisbon nine years afterward. 



757. Few persons h^ve ever taken the trouble to compute (§ 402) 

 Rains at sea and how much the fall of a siuglc iuch of rain over an 



their effect upon its . . . -■ , i ^i i 



equilibrium. extcnsivc pcgiou in the sea, or now much the change 



even of two or three degrees of temperature over a few thousand 

 square miles of its surface, tends to disturb its equilibrium, and 

 consequently to canse an aqueous palpitation that is felt from the 

 equator to the poles. Let us illustrate by an example : The sur- 

 face of the Atlantic Ocean covers an area of about twenty-five 

 millions of square miles. Kow, let us take one fifth of this area, 

 and suppose a fall of rain one inch deep to take place over it. 

 This rain would weigh three hundred and sixty thousand millions 

 of tons ; and the salt which, as water, it held in solution in the 



ably at the mouth of the viver, or upper part of the bay, Avhere the eagi-e is hardly 

 discoverable. In the Bay of Fundy, where the tides rush in with amazing velocity, 

 there is at one place a rise of seventy feet ; but there the magnificent phenomenon 

 in question does not appear to be known at all. It is not, therefore, where tides at- 

 tain their greatest rapidity, or maximum rise and fall, that this M'ave is met with, 

 but where a river and its estuary both present a peculiar configuration. 



"Drvden's definition of an eagre, appended in a note to the verse above quoted 

 from the Threnodia Avgiistalis, is, ' a tide swelling above another tide,' which he says 

 he had himself observed in the River Trent. Such, according to Chinese oral ac- 

 counts, is the character of the Tsien-Tang tides — a wave of considerable height rush- 

 es suddenly in from the bay, which is soon followed by one much larger. Other ac- 

 counts represent three successive waves riding in ; hence the name of the temple 

 mentioned, that of the Three Waves. Both here and on the Hooghly I observed 

 l)ut one wave ; my attention, however, was not particularly directed to this feature 

 of the eagre. The term should, perhaps, be more comprehensive, and express 'the 

 instantaneous rise and advance of a tidal wave ;' the Indian barbarism 'bore' should 

 be discarded altogether. 



" Avery short period elapsed between the passage of the eagre and the resumption 

 of trafiic. The vessels were soon attached to the shore again ; women and children 

 were occupied in gathering articles which the careless or unskillful had lost in the 

 aquatic melee. The streets were drenched with spray, and a considerable volume of 

 water splashed over the banks into the head of the grand canal, a few feet distant.'' 

 Vide Transactions of Chinese Branch of the Royal Asiatic Society. 



