SCIENCE-GOSSIP. 



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together are like a gigantic evaporating dish. As 

 the superficial layers of water are first heated, the 

 process of evaporation causes those layers to hold 

 proportionately more salt, and by the greater 

 density thus produced they sink, carrying heat 

 with them. In addition the sun's rays penetrate 

 to the bottom of these shallows and can conse- 

 quently carry heat directly. 



The local currents of water in the deeper parts 

 of the lagoon are very remarkable, and fishermen 



again rises as that stream is approached. The 

 fall is very remarkable towards the east, but not 

 so much towards the south as the equatorial seas 

 are reached. The local heated Bermudian waters 

 overflow, as it were, the surrounding ocean ; and 

 currents are said to proceed chiefly in the direc- 

 tions north, north-east and north-west. Near the 

 islands they are very swift at times, but are largely 

 influenced in force and direction by the winds and 

 tidal wave. 



Bermuda Islands, Banks and Deep Soundings. 



say that a surface current carries the lead in one 

 direction, while a few fathoms deeper it is carried 

 the opposite way. Apart from any tidal action, the 

 sun must have a powerful effect in disturbing the 

 equilibrium and inducing currents, as previously 

 explained. Whilst swimming one can feel the 

 changes of temperature even in traversing a short 

 distance. 



When carefully examined, the charts of the 

 voyage of the " Challenger " show around Ber- 

 muda an indistinct zone of heated water. The 

 temperature falls towards the Gulf Stream, but 



Vapour-laden, hot, southerly winds prevail in 

 summer, promoting comparatively littleevaporation. 

 In the winter time northern winds are frequent. As 

 may be expected, these are cold and comparatively 

 dry. They sweep over the islands, rapidly ex- 

 tracting heat, which accounts for the low winter 

 temperature of the water. 



We can now understand the cause of this 

 excessive variation of temperature in the shallows. 

 The hot sun pours down in summer time and heats 

 the water to the bottom. The warm damp winds 

 extract but little heat. These circumstances give 

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