226 THE SCOTTISH MARINE STATION AND ITS WOEK. 



and expands in the ordinai'y way^ but as it merely enters the 

 reservoir, b, no reading is possible ; when, however, it is 

 inverted the mercury breaks off at A, flows down the tube, 



Fig. 5. 



Fig. 5. — Negretti and Zarabra's improved 

 Standard Deep-sea Tlierniometer ; and removed 

 from within its protecting tube. A, Constriction 

 above the bulb ; B, reservoir ; c, dilatation at the 

 end of the stem. (From the " Challenger" Nar- 

 rative.) 



Fig. 6. — The Scottish Deep-sea Thermometer 

 Frame. (From the ' EucyclopEcdia Britannica.') 



Fig. 6. 



