and also at other times, but the temperature change was so slight 

 that it barely showed on the slide. 



D. Transparency 



Transparency observations using a 30-cm. white Secchi Disc were 

 made using artificial light. Later on, rust from the sheet metal 

 lining of the icehole fouled the water to an extent where readings 

 were not considered reliable and they were discontinued. There was 

 no opportunity to make correlations with transparency observed in 

 open water under natural sunlight, so the results obtained are largely 

 relative in value. 



E. Current and Biological Observations 



Current observations were made with a standard Ekman meter which 

 was lowered on the regular winch wire. Much of the time two winches 

 were in operation, one of which could be used to lower a fish trap 

 while the other was employed in oceanographic work. Fish traps were 

 kept down over night and collected besides fish, various crustaceans 

 and other bottom invertebrates. A bottom tangle also was used at 

 times. 



F. Bottom Samples 



A 35-pound Phleger corer was tried a number of times at the ice- 

 hole but with very little success, the very hard bottom permitting 

 little or no penetration. The performance of a small Orange-peel 

 sampler was also disappointing. Finally, an 80-pound Peterson bot- 

 tom sampler, similar to ones used by the senior author on Wisconsin 

 lakes during the 1920* s, was tried and proved very successful in 

 obtaining large amounts of bottom sediment. Bottom samples were 

 placed in quart Mason jars and kept wet; a little formalin was added 

 to preserve any soft bodied forms. The larger bottom organisms were 

 picked out from the sediment and given to the Stanford University 

 biologists. 



G. Meteorology 



Meteorological conditions at the icehole were often at great 

 variance with those reported by the Navy Meteorological Station at 

 NAF McMurdo. Lack of instruments at the icehole precluded mainte- 

 nance of a separate weather record except for air temperatures, 

 visual observations, and general weather conditions. During the 

 latter part of the winter a grasshopper automatic weather trans- 

 mitter was installed for several weeks and a barometer was located 

 inside the hut. The day the grasshopper was put down it was -58 F. 



22 



