Observers' Field Reports 197 



A. Sterling, on Magnetic Work in Chile, Bolivia, Brazil, and the Guianas, February 



1917 to July 1918. 



According to instructions of September 16, 1916, from the Director, I was detached 

 from the party under Mr. D. M. Wise, after 4 months of instruction and practice, to 

 undertake independent work. My instrumental equipment consisted of universal mag- 

 netometer No. 21, a pocket chronometer and three watches, observing tent, and the 

 usual accessories. The universal magnetometer was originally supplied with needles 1 

 and 3 of magnetometer No. 19, and 5 and 6 of magnetometer No. 20. Needles 1 of 19 

 and 5 of 20 became so unreliable that they were replaced in June 1917 at La Paz by 1 

 and 2 of magnetometer No. 21. 



I left Mr. Wise at Mollendo, Peru, February 5, 1917, and arrived the following 

 day at Arica, the most northerly port of any considerable size in Chile. After reoccupying 

 the C. I. W. station at Arica, I proceeded by sea to Iquique, arriving February 10. 

 Plans were changed slightly now to take advantage of the continuous railroad connection 

 from Iquique south to the more thickly populated part of Chile. This was especially 

 desirable, in view of the fact that so many vessels had been taken off the west coast 

 for war purposes, while the German vessels were tied up, leaving steamer service con- 

 siderably below normal. From Iquique I continued by train and by steamer to Coronel, 

 Chile, occupying 15 stations en route of which 4 were reoccupations of former stations; 

 2 stations were reoccupied at Coronel, the relocation of one being close and the other 

 exact. 



From Coronel I traveled to Uyuni, Bolivia, making reoccupations en route of my 

 own stations at Santiago and Antofagasta for additional longitude data, as well as 

 additional magnetic data. My ascent from Antofagasta, at sea-level, to Uyuni, 12,000 

 feet, was too rapid, and I suffered an attack of soroche, or mountain sickness, so severe 

 that I gave up the proposed trip to Tupiza and proceeded to La Paz, arriving May 28. 

 Correspondence and computing were brought to date here, a station was occupied, 

 control observations were made for replacing two dip needles, and plans were completed 

 for entering another phase of my trip travel in the jungle. 



On July 4 I went by automobile to Achacache, on the shore of Lake Titicaca, and 

 from there to Sorata on mule-back. After occupying a station at Sorata, and adding 

 to my supplies and camping equipment, I started over the divide on July 17 with a 

 train of 7 mules, 2 of which were saddled for riding. Two Indians drove the mules, and 

 a Bolivian boy, Luis F. Manzaneda, acted as helper and guide, and translated the 

 language of the Aymara Indians into Spanish. The trail was so rough that it was much 

 easier and faster to walk and let the saddle mule stay with the pack train. The descent 

 from the divide, at 16,500 feet, into the jungle, was rapid, and the snow was only a day's 

 travel from orange, lemon, and banana trees. 



We arrived July 25 at Guanay, on the headwaters of the Beni River, an affluent of 

 the Madeira, which in turn flows into the Amazon, and were obliged to remain there a 

 week while the Indians, who otherwise would have guided our raft, stopped to help 

 in the building of a church. After attending the dedication ceremonies, we left Guanay 

 on a well-designed, well-constructed, and well-manned native raft, called a callapo. 

 From Guanay to Rurrenabaque, the head of steam-launch navigation during the wet 

 season, is the most dangerous part of the river. We arrived August 4, a national holiday, 

 when observations were postponed on account of the celebration. 



After further plans were made at Rurrenabaque, I left August 20 on another callapo 

 with 3 Indians, having been delayed several days, first by their celebrations, then by 

 their refusing to start on Friday, and finally by losing a raft and having to construct 

 a new one. A Spaniard, Luis Arroyo, took Manzaneda's place as cook and general 

 helper. The population of Rurrenabaque came to the river and bade us farewell, saluting 



