From Cape of Good Hope to Melbourne. 95 



which, from a line drawn between the Cape of Good Hope 

 and Cape Hangklip, gradually shelves up from a depth of 50 

 fathoms. A prevailing south or south-east wind brings the branch 

 of the Agulhas Current which flows over the Agulhas Bank into 

 False Bay, raising the temperature of the water in Simons Bay 

 6° or 7° C. (11° to 13° F.). This difference was observed not 

 only at the surface but at the depth of 9 fathoms, in which the 

 " Challenger " was anchored, and the change would be accom- 

 plished in the short space of six hours. 



The peninsula, from Table Mountain to the Vasco de 

 Gama Hill, must at one time have been an island about thirty 

 miles long and five miles broad, now joined to the mainland of 

 Africa through the slow silting up of the strait which formerly 

 flowed between Table Bay and False Bay. 



Eastward of the Crozet Islands, the temperature of the 

 Southern Ocean decreases rapidly. The isotherm of 5° C, which 

 at Station 146 is at 50 fathoms, rises to the surface at Station 

 147. The temperature at 100 fathoms, which at the latter 

 station is 2°.9 C, falls to i°.8 C. at Station 150, and to o°.o C. 

 at Station 152. On the morning of the nth February, and in 

 about lat. 60° 40' S., long. 80° 20' E., the "Challenger"' sighted 

 the first iceberg. At 4 a.m. it presented the appearance of a 

 silvery mass dimly visible towards the east-south-east, and 

 was found, by angular measurement, to be over 700 yards 

 long, and to rise vertically on all sides to a height of more than 

 200 feet above the surface of the water. From that date to the 

 end of the month, the narrow horizon commanded from the 

 ship's deck offered the imposing spectacle of a sea studded with 

 icebergs of every size and shape, though generally assuming the 

 form of huge slabs, whose snow-white surface reflected every 

 hue of day — from the delicate silvery-grey of dawn to the 

 golden and crimson tints of sunset, and from the inky dark- 

 ness of their recesses when in the shadow of a cloud, to the 



