Profiles of the air-bubble distribution in ice were made at Site 2. Figures 13 

 and 14 show the distribution of air bubbles for various samples of ice. The East- 

 man Kodak photo-copyer was used again to photograph the ice samples for air- 

 bubble content. A low-power microscope was used to photograph the smaller air 

 bubbles, with the ice samples placed under a grid graduated in 0.5 mm. 



The longitudinal wave velocity of a sea-ice rod was measured by the resonant- 

 rod method. The radius of the rod, obtained by coring, was small in comparison 

 to its length. The rod was allowed to reach a temperature equilibrium over a 

 period of two or three days. A Hewlett-Packard audio signal generator, model 

 205 AG, was used to drive a balanced armature which, in turn, was coupled to a 

 2-inch-diameter plate attached to one end of the ice rod. An earphone was attached 

 to the other end of the rod to detect the waves generated. The signal from the 

 earphone was fed into a Ballantine vacuum-tube voltmeter. 











SNOW 



ICE INTERFACE 



i 







3 







10 



S 

 20 ~ 



40 O 

 



" % 

 60 S 



70 i 



80 

 87.5 







5 '• 























.... 





V 



\ 



















%. 







ICE-WA 



-^ 





f 

 TER INTERFACE 





X 



\ 





^ 

















...J 





---. 



^ 











""■■•.. 



'"■■■■■. 



■"■"■■•■■„„„ 



*"■"■•...,„,„ 



*** 



-**,, 



1 



'B 1 



4 3/ 



8 1 



/2 5 



/8 



3 



4 7 



8 1 



DIAMETER OF BUBBLE (MM) 



Figure 13. Air-bubble size distribution for ice samples of X-V-axis orientation, site No. 2. 



16 



