PHYSICAL OCEANOGRAPHY 



305 



same oceanographical region. In July 19 10 observations were Comparison of 

 made bv the " Michael Sars" at Stations 60 to 6s in the vicinity " ^^^^l^,"^v." ',' 



r 1 ./j—-i 11 M r- • ^ r T o in. t i "^ ^"^^ "Michael 



ot the " Challenger Station 65 ot June 1873. Now, the temper- Sars" 

 atures of the great depths beyond 1000 fathoms prove to be oSvSont 

 identical in these two years, showing that the thermometers 

 worked properly, but in the upper layers it was much colder in 

 1 9 10 than it was thirty-seven years before, the difference in 



Fig. 210.— Comparison of the Temperatures taken by the "Challenger" 



IN 1873 AND BY THE " MiCHAEL SaRS " IN I9IO. 



some cases amounting to about 5' C. at a depth of 700-800 

 metres (400 fathoms). Fig. 210 shows the temperature-observa- 

 tions at the "Challenger" Station 65 and the "Michael Sars" 

 Station 65, between the surface and a depth of 1000 fathoms. 



Observations were taken at the " Michael Sars" Station 51 

 in June 1910, in the vicinity of the "Challenger" Station 354 

 in May 1876. Fig. 211 shows the conditions at these two 

 stations, which varied only to a slight extent ; at certain depths 



X 



