List of Illustrations 



FIGURB PAGB 



1. Energy emitted by a black body 2 



2. Freezing point and temperature of maximum density as func- 



tions of chlorinity and salinity 14 



3. Refractive index and specific conductance of sea water .... 16 



4. Protected and unprotected reversing thermometers 38 



5. The Nansen reversing water bottle 42 



6. Determination of surface currents 45 



7. The Ekman current meter 47 



8. Energy spectrum of radiation from sun and sky 54 



9. Energy spectra in different types of water 55 



10. Percentages of total energy reaching different depths in various 



types of water 57 



11. Effective back radiation from the sea surface to a clear sky . . 59 



12. Temperatures, prevailing wind directions, and frequency of fog 



over the Grand Banks of Newfoundland 65 



13. Annual evaporation from the Atlantic Ocean •. . . . 68 



14. Annual and diurnal variation in the amount of heat given off to 



the atmosphere 69 



15. Average values of surface salinity for all oceans 71 



16. Average annual ranges of surface temperature and radiation . . 77 



17. Annual variation of temperature in Monterey Bay and in the 



Kuroshio 78 



18. Annual variation of temperature off the Bay of Biscay .... 80 



19. Temperature-salinity diagram 87 



20. Results of vertical mixing of water types 88 



21. The formation of a water mass 90 



22. Rotating currents in the Baltic 94 



23,24. Isobaric surfaces and currents in stratified water. . . . 104,105 



25. Geopotential topography of the sea surface off southern Cali- 



fornia 107 



26. Temperatures and sahnities in the Straits of Florida and veloci- 



ties of current Ill 



27. Location of a curve in the pressure field 113 



28. Determination of the depth of no motion 115 



xiii 



