THE SOUTH EQUATORIAL CUREENT. 351 



(315.) H.M.S. Challenger (August 21st— September 6th, 1873) crossed 

 the South Equatorial Current from lat. 3° 25' N., long. 15^ W., 420 miles 

 W.S.W. from Cape Palmas, to Cape San Roque; visiting on the way St. 

 Paul's Rocks and Fernando Noronha. She found the Currents much as 

 represented in the illustrative diagram, page 295, but having generally a 

 greater velocity; thus, in lat. 3° 25' N., long. 15^ W., the Current flowed 

 9 miles to W.S.W. in the twenty-four hours. Thence she steered direct 

 for St. Paul's Rocks, and in long. 17° 30' W. found the Current setting 23 

 miles to the N.W. in twenty-four hours; in long. 20" W., 20 m. W.N.W. ; 

 in 22° 30' W., 17 m. N.W. ; in 24° 30' W., 26 m. W.N.W. ; in 26° 30', 21 m! 

 W. by N.; in 29° W. (50 miles E.N.E. from St. Paul's Rocks) the high 

 velocity of 39 m. to W. by N. was found; at 70 miles S.W. of St. Paul's 

 Rocks, 29 m. W.N.W. ; midway between St. Paul's Rocks and Fernando 

 Noronha, 25 m. S.W. ; near Fernando Noronha, 21 m. West; at 60 miles 

 S.W. of Fernando Noronha, 27 m. N.W.; at 90 miles East of Cape San 

 Roque, 30 m. W.N.W. ; and on the coast of Brasil the Currents were gene- 

 rally found flowing to the N.W. and West, as far as 15° S. 



The wind at the commencement of this passage blew from the S.S.E., but 

 afterwards came more from the Eastward. At Cape San Roque its direc- 

 tion was from the S.E., varying in force from 3 to 5 (Beaufort scale, see 

 page 104). The temperature of the surface water observed in this passage 

 varied from 77° to 78°. At a depth of 10 fathoms in the Eastern and cen- 

 tral part of the region traversed, the temperature of the water was 78° 

 while near St. Paul's Rocks at this depth it was only 77°, and near Fer- 

 nando Noronha only 75°. At 50 fathoms, in the central part of the district, 

 it was 62° to 63°, and in the Western 67°. At 100 fathoms the tempera- 

 tures were from 55° to 57°, and at 1,000 fathoms 36° to 37°. The higher 

 temperature at 50 fathoms in the Western than in the Eastern part of the 

 district, seems to indicate the banking up of the warm water to the West- 

 wax d by the prevalent wind. 



(316.) On this Current the following is extracted from Mr. R. Strachan's 

 remarks in the Meteorological Report, 1872 : — 



The South Equatorial Current commences on the African coast, and 

 seems to extend at times as far as to 3° N. lat., though more commonly 

 here it is not found beyond 1° N. To the first meridian its rate is from 12 

 to 17 miles. It now extends generally to lat. 3° N., and maintains this 

 limit to long. 25° W., during a course nearly West of over 1,500 miles, at 

 rates changing from 26 to 12 miles per day. It now has a tendency to the 

 N.W., and attains lat. 6° or 7° N., and, as a general result, maintains this 

 limit until it reaches the coast of Brasil. Near the Equator the mean rate 

 is less than 24 miles per day, and this becomes lower as the latitude in- 

 creases, so that in lat. 5° N. its velocity is less than 18 miles. For nearly 

 300 miles from the coast of Brasil and Guayana the direction of the Current 

 is affected by the land. Off Brasil, the rate is from 62 to 37 miles per day; 

 off Guayana, it is from 31 to 24 miles. Having passed the 50th meridian, 

 the Northern edge merges with the Westerly Drift of the North Equatorial 

 Current, though in some months this is effected in longitudes more to tha 

 Eastward, even so far as the meridian of 25° W. 



(317.) Commander J. R. Bartlett, U.S.N. , from examinations made in 



