THE HEART OF THE ANTARCTIC 



Large Crystals in Creyasses 



Similar crystals to those referred to elsewhere by 

 Mawson, seYeral inches in diameter, were found in the 

 shafts sunk in the lakes. These were thin triangular 

 plates, growing from the wall, to which they were attached, 

 sometimes by a side, sometimes by an angle. They were 

 regularly striated in lines parallel to one side. Some were 

 twinned, two series of stride meeting in the centre of a 

 symmetrical plate. Designs were built up by the growth 

 of new crystals from the free edges of others, or even from 

 angles. 



Ice-flowers occurred on fresh- water ice at Clear Lake 

 and Blue Lake. They were on the ice rapidly and tran- 

 quilly formed in the trenches sunk for the obserYation of 

 temperature. They were much smaller than those on the 

 sea-ice, being only half an inch or less in diameter. 



In the height of summer the combined action of the 

 sun and air on compacted snow-drifts caused deep erosion 

 of the snow. A kind of stratification resulted which 

 appeared to haYC no relation to any original stratification 

 of the snow. Thin flat layers of ice were formed, separated 

 by caYities. These dipped at a gentle angle to the south, 

 that is to say, their edges were directed towards the sun 

 at the time of day when it is highest. These ice plates 

 were so fragile that they coUapsed in multitudes as we 

 walked OYcr the drifts, and a shght breeze whirled 

 quantities of them along, often rolling on their edges. 



Temperatures of Lake-ice 



During the winter a series of shafts were cut through 

 the ice of most of the lakes, in order to obserYC the tem- 

 perature at different depths. The first trenches at Clear 

 Lake were the work of the whole scientific staff. After 



362' 



