THE EXPLORATION OF THE SEA 



[part I 



n 



Fig. 3. A. The Negretti and Zambra deep-sea reversing thermometer. The 

 messenger is lowered down the line, strikes the catch C which then lifts 

 the rod jR from a depression in the thermometer case. The latter then turns 

 over or reverses, breaking the mercury thread in the thermometer. B. The 

 most recent deep-sea reversing thermometer (Richter's pattern). C. A Kiel 

 hydrometer 



