498 CURRENTS AND WHALING. 



island of St. Helena, little or no current is ever experienced. This is 

 rendered certain by the fact that vessels, which in striving to reach 

 it, have fallen to leeward, find no difficulty in beating up. The 

 following directions for reaching the island are found both in Hors- 

 burgh and Purdy. 



" Before the use of chronometers and lunar observations, navigators 

 were directed, in running for St. Helena, to fall into its parallel fifty 

 or sixty leagues eastward of it, to lie by in the night, and steer west 

 in the day till they made the land : this practice is no longer requi- 

 site, for most of the East India ships, homeward-bound, steer now a 

 direct course from the Cape to St. Helena, and make the island by 

 day or night; as they generally know the longitude within a few 

 miles of the truth, there can be little danger of missing it, although 

 this is barely possible, the body and leeward part of the island being 

 frequently enveloped in fog clouds, particularly in the night. Should 

 a ship, in such case, fall a little to leeward, she will seldom find any 

 difficulty in working up to the anchorage, unless she sail indifferently 

 upon a wind, for the current seldom runs strong to leeward near this 

 island : this, however, may happen when the trade blows strong, 

 with squalls, for a few days, which is sometimes experienced about 

 the full and change of the moon : but this lee-current is generally of 

 short continuance. In time of war, when any of the enemy's cruisers 

 visit St. Helena, they keep to the eastward and southeastward of it, 

 at the distance of fifteen, twenty, and twenty-five leagues. Single 

 ships, which sail well, would avoid these cruisers, were they to make 

 the island bearing from north-northeast to east and southeast, and 

 afterwards make short tacks under the lee of it till they reach the 

 anchorage. I have seen store-ships from England make the island, 

 bearing east-southeast, directly to windward of them, at the distance 

 of fifteen or eighteen leagues; they sailed indifferently, but reached 

 the anchorage the third day after making the island." 



The deep-sea temperature near St. Helena proved that the influ- 

 ence even of a submarine polar current was not experienced there. 



It would therefore appear that the South Atlantic is the seat of a 

 system of currents, analogous, but simpler in form, than those of the 

 North. 



Off Cape Horn, we encountered the Great South Polar Stream, 

 whose strength has had such influence on the progress of vessels, and 

 been the cause of so much disaster to the early circumnavigators. 

 This stream spreads far to the eastward, and Cape Horn divides it 



