Q2 THE OCEAN 



There can be no doubt that these very low 

 deep-sea temperatures have their origin very 

 largely in the Southern or Antarctic Ocean, 

 the ice-cold waters of which are slowly 

 propagated northwards, the rate of propaga- 

 tion being so slight as to be regarded rather 

 as a slow creep than as a distinctly recog- 

 nisable movement of the water. At the same 

 time it is evident that the increase of tem- 

 perature from the bottom of the ocean to the 

 surface is due to the descent of the denser 

 waters of the surface carrying downwards 

 their higher temperature and salinity even 

 to the bottom. 



Temperature Conditions in the Black Sea. — 

 By way of contrast with the temperature 

 conditions in the open ocean it is interesting 

 to glance at the state of matters in an enclosed 

 sea, like the Black Sea, which is the receptacle 

 for a large body of dense water introduced 

 from the Mediterranean into its deeper parts, 

 where it lies in an almost stagnant condition, 

 covered by a superficial layer of comparatively 

 fresh water. Vertical circulation is limited 

 to the superficial layer, and this leads to pecu- 

 liar physical conditions, and to the almost total 

 absence of life in the deeper water, where there 

 is an abundant formation of sulphuretted 

 hydrogen. 



In July, 1890, the temperature at the 



