PLATES (Cont'd) 



Page 



XXVII. Bulldozing Away the Snow Accumulation with Low Ground 

 Pressure D-8 Tractor and 16-foot Blade. Royal Society 

 Range Across McMurdo Sound in Background . 26 



XXVIII. East Side of Icehole Hut Showing Snow Accumulation 



Partially Removed. Mt. Discovery in Left Background 26 



XXIX. Dissolved Oxygen Titration Apparatus in the Stanford 



University Biological Laboratory at NAF McMurdo 29 



XXX. Ice Break-up 10 March 1961. Icehole Hut in Foreground. 

 Hut Point in Background with Lower Slopes of Observation 

 Hill to the Right 31 



TABLES 



1. Seasonal Variation of Water Temperature at Depth at the 



Icehole 33 



2. Water Temperature, Means and Ranges at the Icehole 37 



3. Seasonal Variation of Salinity at Depth at the Icehole .... 43 



4. Seasonal Variation of Density at Depth at the Icehole 51 



5. Seasonal Variation of Sound Velocity at Depth at the 



Icehole 53 



6. Seasonal Variation of Dissolved Oxygen at Depth at the 



Icehole 57 



7. Seasonal Variation of Percent Saturation of Dissolved 



Oxygen at Depth at the Icehole 61 



8. Percentage Saturation of Dissolved Oxygen in McMurdo 



Sound and Other Areas in the Ross Sea 63 



9. Current Observed at the Icehole 65 



10. Astronomical Data, 1960 79 



