Plate XVI.— Fragments of iceberg hoisted 

 aboard. This ice is hard and homogene- 

 ous. Its opacity is due solely to great 

 numbers of tiny spherical air bubbles 



Plate XVII.— Swimming close to an iceberg in 58° surface water. This ice is not in the Gulf Stream, 

 but is in a great pool of Labrador current water that has been highly warmed at the surface by 

 continued vernal warming. At 10(1 feet below the surface the temperature was less than 40 F. 

 The striping on the sunlit berg wall directly behind the swimmers may be due to differential 

 melting between annual layers accumulated on the ice cap of ( ireenland. Taken from ship's boat 

 Julv 18, 1929, latitude 42° 28' N., longitude 50° 05' \V. 



