ICE-CAVERN. 725 



further end it narrowed to a mere gallery, 

 where the roof was pierced by a circular win- 

 dow, quite symmetrical in shape, through 

 which one looked up to the blue sky and 

 drifting clouds. There must be strange ef- 

 fects in this ice-cavern, when the sun is high 

 and sends a shaft of light through its one 

 window to illuminate the interior. 



This first excursion was a mere reconnais- 

 sance. An approximate idea of the dimen- 

 sions of the glacier, and some details of its 

 structure, were obtained on a second visit the 

 following day. The anchorage for the night 

 was in Playa Parda Cove, one of the most 

 beautiful of the many beautiful harbors of 

 the Magellan Strait. It is entered by a deep, 

 narrow slit, cut into the mountains on the 

 northern side of the Strait, and widening at 

 its farther end into a kind of pocket or basin, 

 hemmed in between rocky walls bordered by 

 forests, and overhung by snow and ice-fields. 

 The next morning at half-past three o'clock, 

 just as moonlight was fading before the dawn, 

 and the mountains were touched with the 

 coming day, the reveille was sounded for 

 those who were to return to Glacier Bay. 

 This time Agassiz divided his force so that 

 they could act independently of each other, 



