RESTRICTED 



6.2 Measureraent of temperature and chemical constituents 



The distribution of temperature and chemical constituents 

 has provided information on diffusion rates, lateral mixing, 

 and cxorrents. Heversing thermometers and Nansen bottles vere 

 used to measxire the temper at \ire and collect a water sample at 

 any desired depth. The Nansen bottle is a tubular instrument 

 with a valve at each end. The bottle is lowered v/ith the valves 

 open so that the water passes ireeiy through the bottle. A 

 "messenger*' sent do\vn the v;i:'e trips a mechanism wnich releases 

 the upper end of the bottle so that it turns upside aov/n, clos- 

 ing the valves ana entrapping a water sample. The thermometer 

 mounted on the side of the i^ansen bottle is designed so that 

 turning it upside down breaJiis the thread of merciiry, and the 

 thermometer records the temperature at the time of reversal. 



The salinity of the v/ater samples v/as determined by the 

 Knudsen method based on a chloride titration with silver nitrate, 

 The Winkler method was used for oxygen analyses, and the Atkins- 

 Deniges method for phosphate. 



6.3 Tides and sv;ell 



Tides vrere measiired by two standard tide gauges. One v/as 

 located in shoal water in the eastern part of the lagoon near 

 Bikini Island, the other on the outer reef. Portable 24-hour 

 gauges were also used occasionally in various places, b'v/ell 

 was computed from an instrument which measured short period 

 pressure fluctuations on the bottom in shoal water. 



) 



