66 



THE OPAL SEA 



Effect of 

 blue sky. 



coast or on the ship's side, there will be rush- 

 ing crests of green-and-white foam. This is 

 equally true of the Gulf Stream, which beats 

 up into a deep green in storm for all the indigo 

 of it under sunlight. 



It would seem then that while the sun-and- 

 sky color of sea water is blue, its local color 

 as seen under neutral light is pale green or 

 graj'^-green. Many minor illustrations rise up 

 readily enough to confirm such a belief. The 

 stories told by the sponge-fishers and pearl- 

 divers are all of green water below the surface ; 

 at Venice the reflection of the gondola in the 

 canals is not blue or black but green; and sail- 

 ing into the Bay of Naples on a clear day, the 

 water appears intensely blue while the same 

 water seen in the tanks of the Naples Aquarium 

 is green. 



Possibly the salt particle is responsible for 



gives 



Local color 

 of tea water 

 is green. 



Salmily 

 avil its 

 effect. 



the great bulk of local sea coloring. It 

 us blue when the light is reflected, green when 

 it is transmitted, grays, purples, and mauves 

 when it is broken. The salt particle — salinity 

 — also gives body and quality to the color. The 

 waters of the polar regions, continually fresh- 

 ened by snow and ice, are much lighter in hue 

 than those under the equatorial sun, rendered 

 densely saline by the unceasing evaporation of 



