Chapter IV—From Cape of Good Hope to Sydney. 
THE SOUTHERN OCEAN. 
HE “ Challenger ” left her anchorage in Simons Bay on the morning of the 
17th December. The stormy latitudes we were about to enter gave but little 
hope that we should be able to carry on sounding and dredging operations 
with the regularity to which we had been accustomed. The first few days 
after our departure, however, were unusually fine, and, while the dredge 
reaped a rich harvest at the bottom of the sea, we succeeded in making an interesting series 
of observations on the great current from the Indian Ocean known as the Agulhas or Cape 
Current. We had traversed a patch of cold water of a temperature of 13 0 C. just outside 
False Bay. From that hour—10 a.m. on the 17th—the temperature of the sea-surface steadily 
increased, until, between 1 and 2 a.m. on the 19th, it suddenly rose from 19 .4 C. to 22 .2 C., 
attaining a maximum of 22°.8 C. at noon of the same day. This temperature was found to 
extend to a depth of over twenty fathoms. With the exception of a narrow streak of colder 
water, the surface-temperature continued at 22°.2 C. until 2 a.m. on the 21st, when it began 
to fall, and at midnight of the same day it was as low as 13 .9 C. The course run, between 
the hour we had entered this body of warm water on the 19th, and the time of our crossing 
its southern limit on the 21st, measured about 250 miles. Thus we had discovered at a 
distance of 200 miles to the south-east of the Cape an accumulation of warm water 250 miles 
broad, over 120 feet in depth, and of a temperature nearly io° C. higher than that of the 
surface-water in the vicinity of the Cape. This mass of warm water is no doubt due to 
the current which is known to flow in a south-westerly direction along the east coast of 
Madagascar and South Africa. 
Stormy weather, rain, and heavy seas set in on the 21st the anniversary of our 
departure from Portsmouth—and put an end to our experiments for a time. On the 24th, 
the temperature of sea and air had fallen to 6° C., while everything on board told of a ship 
bound for the wintry regions of the Antarctic. Black chimney-tops protruded their crooked 
