THE CAPTAIN'S REPORT 



11 



ocean depth was out of order for the morning sounding at 

 8h. At lOh 30m repairs had been made and a sounding 

 gave a depth of 1445 meters as against a depth of 4000 

 meters the previous evening. At noon the depth was 

 1186 meters, so orders were given to heave the vessel 

 to for a wire sounding and bottom sample. A water bot- 

 tle, with protected and unprotected thermometers, was 

 sent down also. The wire angle was 12°, which gave a 

 depth of 1188 meters. The thermometer gave a depth of 

 1168 meters, thus giving a close agreement between all 

 three methods. The bottom sampler brought up an ex- 

 cellent sample of greyish white globigerina ooze. Thus 

 a new ridge was discovered about ten miles across and 

 3000 meters higher than the surrounding ocean bed. 

 Soundings were made at intervals of two hours during 

 the afternoon. At 15h, three miles after the vessel had 

 left the position of the ocean station, the depth was 1260 

 meters; at 16h, nine miles distant, it was 2751 meters; 

 at IBh, twenty miles distant, it was 3620 meters; and at 

 20h, thirty-two miles distant, it was 4115 meters. Thus 

 in a distance of thirty-two miles the depth changed from 

 1168 meters to 4115 meters. Ten miles was the dis- 

 tance run between the first sounding of 1445 meters (25° 

 03'.2 south, 82° 20'.0 west) and the sounding of 1260 me- 

 ters (24° 54'.0 south, 82° 13:0 west) before it began to 

 deepen. 



This ridge, named "Merriam Ridge" in honor of 

 the President of the Carnegie Institution of Washington, 

 Dr. John C. Merriam, is probably an extension to the 

 northwestward of the peaks terminating in the islands of 

 San Felix and San Ambrosio, one hundred and forty 

 miles to the southeast. Time and the limitations of ma- 

 neuvering a sailing vessel did not permit more explora- 

 tion in this region. 



The last five days of the cruise were characterized 



by unusually cloudy weather, so that the program of 

 declination observations twice daily was not possible. 

 The temperature of the surface water dropped from 21? 5 

 to 19° C, when the vessel was seventy-five miles south- 

 west of Callao, and remained at 19° C until our arrival 

 there. The drop was sudden, indicating that we had en- 

 tered the cold Humboldt or Peruvian Current which 

 flows northward as far as Ecuador. 



The vessel's position was determined by star sights 

 early in the morning of January 14 on Rigel and Arcturus, 

 seen for brief moments through rapidly moving clouds. 

 Course was then set for the north end of San Lorenzo 

 Island, off Callao, and for over fifty miles this course 

 was not changed, bringing the vessel to within one mile 

 of the desired point at 14h. The Carnegie then proceeded 

 under engine power and was anchored in Callao harbor a 

 few hours later. 



During the part of the cruise from Balboa to Callao 

 the following observations were made: 96 declination 

 measurements, 34 inclination and horizontal-intensity 

 measurements, 36 ocean and townet stations; 143 sonic 

 depths; 8 atmospheric-electric runs of twenty-four 

 hours; 44 pilot-balloon flights; 12 series of evaporation 

 measurements; 50 days of complete potential gradient 

 records; 43 biological collections; 23 bottom samples; 

 and regular continuous ncords of thermographs and 

 barographs. Observing conditions were excellent during 

 the entire time with the exception of only one or two days. 



The radio conditions were difficult during the better 

 part of the last two months. The indications were that 

 the difficulty may be in local conditions of the general 

 region traversed; whether this is a permanent condition 

 of the region or only a temporary one is an interesting 

 question. 



CALLAO, PERU TO PAPEETE, TAHITI, FEBRUARY 5 TO MARCH 13, 1929 



The Carnegie sailed from Callao Bay under her own 

 power at 15h 20m, February 5, using the engine until the 

 next morning because there was no wind. Here the reg- 

 ular observational program began with an ocean station, 

 and continued without interruption, except for a stop of 

 one day at Amanu Island, until arrival at Papeete, on 

 March 13. The weather was excellent, with good breezes 

 and no storms. The engine was not required except 

 when the trade wind was interrupted among the Tuamotu 

 Islands and during the squally weather near Tahiti. 



The magnetic work was carried out as usual by 

 Torreson, Soule, Scott, Paul, Jones, and Ault. Experi- 

 ments to determine horizontal intensity with the earth 

 inductor were continued biy Soule and Torreson. Vari- 

 ous coils were used and some encouragement was 

 given for ultimate success by the improved agreement 

 of results with those of deflector 5. 



The usual atmospheric-electric program was car- 

 ried out by Parkinson, assisted on diurnal -variation 

 days by Torreson. Twenty-three complete potential 

 gradient records were obtained and three and one-half 

 diurnal runs were mauc. Considerable time was spent 

 by Parkinson in attempts to operate the radioactive con- 

 tent collector and some progress was made. 



The oceanographic work was entirely successful as 

 carried out by Ault, Soule, Seiwell, Paul, and the deck 

 and engine-room force under Erickson and Leyer. One 

 of the new bottom samplers made at Callao gave some 



trouble by failure to close, but the difficulty was over- 

 come by Leyer. The lead weight was countersunk to al- 

 low it to fit down over the clamping spring, thus bringing 

 the center of gravity of the falling snapper nearer to the 

 jaws, to insure that they strike the bottom in an upright 

 position. Only once did the attempt to secure a sample 

 fail. At one station no attempt was made. The samples 

 themselves have shown considerable variation, the colors 

 ranging from white to gray, light brown, blue-green, 

 coffee-colored, chocolate, and black mud, sand, ooze, 

 and lava. One of the new Sigsbee reversing frames (fig. 

 29) was modified to hold two of the Richter and Wiese 

 thermometers, and was sent down on the drift wire, 20 

 meters above the snapper, at each ocean station after 

 February 27. Thus the bottom temperature and the depth 

 were secured in addition to the bottom sample. Experi- 

 ment showed that it requires 25 meters of vertical haul 

 to reverse the thermometers. 



Up to February 28 five minutes had been allowed to 

 elapse after the bottle series had reached the proper 

 depth before releasing the messenger for reversal. Ow- 

 ing to a slight discrepancy between the two temperatures 

 at the overlapping depth, it was decided to allow ten min- 

 utes to elapse hereafter, before reversal begins. The 

 temperatures undoubtedly were accurate for the protect- 

 ed thermometers, but there might be some lag in the 

 unprotected tube with its load of surface water to cool 

 off and the pressure effect to register. An improvement 



