THE PHYSICAL CONDITION OF THE OCEAN. 355 



when combiued in one direction, anionnt to a very considerable fraction 

 of the principal Innar and solar tides, and consequently greatly increase 

 or diminish their effects, are in (Jreat ]5ritain so insignificant that their 

 influence is trifling; but why this should be I have never yet found any- 

 one to explain. ISTevertheless there are many very curious i)oints about 

 our tides which are i»]ainly caused by interference, or, in other words, 

 by tlie meeting of two tidal waves arriving from opiiosite directions or 

 from the rebound of the tidal waves from other coasts. This effect, 

 also, it has been so far found impossible to i^redict without observation. 

 On our southern coasts, for instance, in the western part the tide rises 

 about 15 feet, but as it travels eastward the range becomes less and 

 less until, about Poole, it reaches a minimum of G feet. Farther east 

 again it increases to Hastings, where the range is 24 feet. Yet farther 

 east it again gradually diminishes. This is due to the reflection from the 

 French coast, which brings another wave which either superposes itself 

 upon or reduces tlie effect of the main tide advancing up the English 

 Channel; but the details of such retlection are so complex that no one 

 could forecast them without more knowledge than we i)ossass. There 

 can be little doubt tliat to this cause — reflection — is mainly due the vari- 

 ations in the amount of mean range of tide which are found on many 

 coasts at different parts; and as these reflected waves may arrive from 

 great distances and be many in number, we may cease to wonder at the 

 extraordinary differences in range of tide which prevail, though it will 

 be understood that this is wholly separate from the varying heights 

 of each successive tide or of the tide at different parts of each lunation, 

 or at different times of the year, Avhich depend upon the astronomical 

 influences. 



The actual height of the tide in deep water is small, but on passing 

 into shallow water when approaching a shore, and especially when roll- 

 ing up a gulf of more or less funnel shape, it becomes increased by the 

 retardation caused by friction and by compression laterally, and hence 

 the height of the tide on a coast affected by other causes is greater than 

 in the open sea. The oceanic tide wave is supi)osed to be from 2 to 3 

 feet in heiglit, but as this has been assumed from observations made 

 at small oceanic islands where, although the magnifying influences 

 mentioned are at a miiiimnni, they still exist, we wait for precise infor- 

 mation until some means of actually measuring the tide iu deep 

 water is devised. 



The waves due to wind, though not so far-reaching in their effects as 

 the majestic march of the tide wave, are j)henomena which are more 

 apparent to the traveler on the ocean. The deep sea in a heavy gale 

 presents, perhaps, the most impressive manifestation of the powers of 

 nature which man can behold, and doubtless many of us have expe- 

 rienced feelings that may vary from awe and wonder to sheer delight, 

 according to the temperament of each individual, at for the first time 

 finding himself face to face with this magnificent sight, though I rather 



