THE TIDES 153 



these movements are quite sluggish, for the cooler 

 water of the Arabian Sea, flowing in to supply the 

 deficiency caused by the evaporation, is met at the 

 bottom, its natural place, by the heavy extra-salt 

 water, and the result is a constant struggle between 

 the two, resulting in these two seas being the saltest 

 in the world, as might be expected, seeing how 

 much condensation takes place, leaving all the salt 

 behind, and that no rain falls to redress the balance. 



An interesting question in the consideration of 

 the rising of the great tidal waves naturally presents 

 itself do these swellings of ocean in their path round 

 the world never come in contact with each other, with 

 the effect of neutralizing their forces ? This question 

 has been carefully studied by acute investigators, and 

 some very surprising results have been recorded. On 

 the Irish coast, almost opposite to the Bristol Channel, 

 where nearly, if not quite, the greatest vicissitudes of 

 tide in Britain are experienced, there is an utter 

 absence of rise and fall. The ebb and flow are felt 

 along the coast, but the meeting of the tidal waves 

 here produces an equilibrium, and on the shore the 

 waters remain level. There is another area in the 

 North Sea where the tidal waves meet and balance 

 one another so nearly that only an oscillation of a 

 couple of feet occurs. But the way in which the lines 

 of coming and going tide curve and recurve in this 

 part of the sea are so many and so confused that only 

 the brain of a man entirely at home with the higher 

 mathematics could keep the run of them. Another 

 curious result of the meeting of tidal waves is found 

 in some ports, notably in the roadstead of Havre, 

 where the period of "slack water," as seamen term 



