SMITHSONIAN REPORT. 1956. — SMITH 



PLATE 4 



Samples of sea water used in the measurement of ocean currents are taken in special steel 

 containers known as Nansen bottles. A series of these, open at each end, is lowered on 

 a cable to the required depth. Weights are then sent down the cable which release one 

 end of each bottle so that it turns upside down, at the same time closing each end so as 

 to trap water from the required depths. Thermometers may be seen in metal tubes at- 

 tached to the side of the bottles for measuring the temperature at each depth. 



