Chapter Page 



7. UNDERWATER PHOTOGRAPHY 



General remarks , 72 



Instructions for operating the single-shot bottom contact camera 72 



8. OBTAINING BIOLOGICAL SPECIMENS 



General remarks 78 



The half-meter plankton net 78 



Clarke-Bumpus quantitative plankton sampler 79 



The midwater trawl 82 



Preservation of biological specimens 85 



9. CURRENT MEASUREMENTS 



General remarks 87 



Instructions for operating the Geomagnetic Electrokinetograph (GEK) 87 



Instructions for operating the Ekman current meter 92 



Instructions for operating the Price current meter 94 



Instructions for operating the Roberts radio current meter 95 



10. SEA AND SWELL OBSERVATIONS 



General remarks 102 



Definitions of oceanographic terms 102 



Instructions for operating the electric wave staff 104 



Analysis of wave traces 



11. METEOROLOGICAL OBSERVATIONS 



General remarks 110 



Types of observations 110 



Instructions for operating the recording pyrheliometer 111 



12. WATER TRANSPARENCY AND LIGHT ABSORPTION MEASUREMENTS 



General remarks 114 



Transparency measurements with the Secchi disk 114 



Determining water color with the Forel scale 114 



13. SHIPBOARD CHEMISTRY 



General remarks 115 



General laboratory equipment 115 



General laboratory techniques and precautions 117 



Determination of chlorinity and salinity of sea water 120 



Determination of dissolved oxygen content of sea water 130 



14. INSTRUCTIONS FOR RECORDING OCEANOGRAPHIC OBSERVATIONS, 



MEASUREMENTS, AND SAMPLES ON LOG SHEETS 



General remarks 138 



Oceanographic log sheet A, station and thermometer data 139 



Oceanographic log sheet B, bathythermograph observations 143 



Oceanographic log sheet C, dissolved oxygen determination 144 



Oceanographic log sheet D, chlorinity and salinity determination 146 



Oceanographic log sheet E, station summary 147 



Oceanographic log sheet GEK 1, electromagnetic current observations 151 



Oceanographic log sheet GEK 2, electromagnetic current computations 152 



Oceanographic log sheet L, inshore survey station sheet 153 



Oceanographic log sheet M, bottom sediment data 155 



Shipboard wave observation log 156 



Ship and aircraft ice log 156 



BIBLIOGRAPHY 159 



APPENDIX 



A. Malfunctional behavior and its correction in deep sea reversing thermometers 



with notes on the operation of the Richter and Wiese reversible thermometer 



and the elimination of disturbances 161 



B. A method for determining pressure coefficients of unprotected reversing ther- 



mometers at sea 171 



H. O. 607 



