NARRATIVE OF THE CRUISE. 193 



found running N.E. T3 miles per hour. On the 21st, at Station 102, the dingey was 

 anchored by the lead line, and the surface current was found running N.W. 1*25 miles 

 per hour. These results confirm the existence of the current as ascertained by difference 

 between D.R. and observations. From Porto Praya to the parallel of 12° 30' N. a S.W. 

 current was experienced ; from thence to the parallel of 4° 40' N. the current was easterly, 

 trending sometimes north, and sometimes south, by east. The total drift experienced 

 between the parallels of 12° 30' and 4° 40' was 146 miles in a N. 88° E. direction (true), 

 or at an average rate of three quarters of a mile per hour. Southward of the parallel of 

 4° 40' N. the current was westerly. The temperature of the easterly or Guinea Current 

 was 79° or l° - 5 higher than the Ecpiatorial or westerly Current. 



In the equatorial section from the position in lat. 3° 8' N., long. 14° 49' W. to St. 

 Paul's Rocks, seven soundings, four serial temperature soundings, and three trawlings 

 were obtained (see Sheet 12). 



The surface water maintained an average temperature of 78°. 



The bottom temperature at depths exceeding 1800 fathoms varied 0°"8 or from 36° to 

 36°"8, the mean being 36°"4. 



The serial temperature soundings showed a rapid cooling of the water near the sur- 

 face, for the isotherm of 60° was at an average depth of 70 fathoms. Below 70 fathoms 

 the temperature fell more slowly, the isotherm of 50° occupying an average depth of 

 150 fathoms, varying from 130 to 180 fathoms, and that of 40° being at an average 

 depth of 520 fathoms, varying from 430 to 550 fathoms (see Diagram 4). 



On the 23rd August, at Station 104, the cutter was anchored by the trawl, and the 

 surface current found to run west (true) 1*2 miles per hour. On the 25th August, at 

 Station 106, the cutter was again anchored by the trawl, and at 10.30 a.m. the surface 

 current was running west (true) 2 miles per hour, but in the afternoon its velocity had 

 decreased to 1 mile per hour. The current drag at 10 a.m. at 75 fathoms showed 

 no current, at 50 fathoms a current of half a mile per hour, and at 15 fathoms three 

 quarters of a mile per hour, all to the west, thus showing how very superficial the 

 Equatorial Current is. On the 26th August, at Station 107, the cutter was again anchored 

 by the trawl, and the surface current found to be running west (true) 1*5 miles per hour, 

 and it continued to run at that rate throughout the day instead of slacking in the afternoon 

 as on the 25th. 



The following anemometer observations were taken when, the ship being stationary 

 for sounding or dredging purposes, a favourable opportunity presented itself for ascer- 

 taining the velocity of the trade wind : — 



(XARH. CHALL. EXP. — VOL. I. 1884.) 25 



