334 



DR ALEXANDER BUCHAN ON 



depths from the Mediterranean Sea. A striking contrast in salinity is seen in the two 

 portions of the North and South Atlantic respectively. Thus, while in the North 

 Atlantic the salinities at the surface, 100 fathoms, and 200 fathoms are 1'0273, 1*0271, 

 and 1*0269, in the South Atlantic they are 1*0272, 1*0266, and 1*0260 ; so that through 

 this depth the salinity is reduced three times more in the South Atlantic as compared 

 with the North Atlantic. On the other hand, in the Gulf of Guinea the salinity is at 

 the surface and at all depths less than in the North and the South Atlantic areas, owing 

 to the heavy rainfall in this part of the ocean and lands adjoining and the east flowing 

 current in this part of the equatorial region of the Atlantic. 



In the Pacific by far the greatest salinity at the surface and, as in the above cases, 

 through all depths to the bottom is to the east of Australia, whither the surface currents 

 are propelled by the trade winds. It may be noted that the distribution of salinity in 

 this region of the Pacific from 200 fathoms to the bottom is all but identical w T ith that of 

 the region in the South Atlantic. The area of lowest salinity is the region lying between 

 Japan and the Sandwich Islands, which is further characterised as the region of lowest 

 salinity of all the oceans exclusive of the higher latitudes. And this lower salinity is 

 also carried down through all depths to the bottom of the ocean, as shown by the six 

 Maps of Salinities. 



The following are the salinities and specific gravities in three regions in the higher 

 latitudes : — 



Salinities. 









Southern Ocean. 



Arctic Ocean. 





Lat. 30° to 55° S. 

 Long. 53° to 133° W. 



Lat. 40° to 65° S. 

 Long. 80° to HO" E. 



North of 



Wyville-Thomson 



Ridge. 



Surface, .... 



1-0255 



1-0255 



1-0258 



100 fathoms, 







253 



254 



258 



200 







253 



255 



259 



300 „ 







253 



255 



257 



400 „ 







253 



255 



259 



800 







255 



... 





1500 







254 



255 



258 



Specific Gravities. 





Surface, .... 



1-0263 



1-0270 



1-0274 



100 fathoms, 







266 



271 



277 



200 „ 







267 



273 



278 



300 „ 







270 



273 





IOC „ 







271 



274 



281 



800 







275 





281 



1500 







277 



277 



281 



2000 







278 



278 





