DEPARTMENT OF TERRESTRIAL MAGNETISM. 289 



trades, the southwest monsoon was encountered, and this wind contin- 

 ued until our arrival at Colombo. The route extended up into the Ara- 

 bian Sea in order to cross the Carnegie's 1911 track and to relocate the 

 agonic line. "WTiile crossing this line, 6 declination determinations 

 were made in 25 hours with perhaps more than the usual accuracy, in 

 spite of the gale which was blowing. 



At midnight on June 26 the light on Minikoi Island was sighted as 

 expected. Eastward of Minikoi the monsoon was very light, so that 

 the Carnegie did not reach Colombo until the morning of June 30, 

 after being hove to off the port all night. The distance covered from 

 Cape Town to Colombo was 6,665 miles, giving a high average run of 

 163.4 miles for the trip of 40.8 days. 



The trip from Cape Town was unusual in tliat declination observations 

 were made daily in spite of the unfavorable weather conditions. Rain 

 or precipitation of some kind occurred on 29 out of 40 days. On but 

 6 days were declination observations made only once, on 29 ds.ys they 

 were made twice, on 3 days they were made three times, and on 1 day 

 they were made four times, when relocating the agonic line. The 

 chart errors in declination for the southern part of the Indian Ocean 

 averaged over 1 degree, sometimes reaching 2.5 degrees. In the north- 

 ern part they were less than 0.5 degree. 



At Colombo an extended program of intercomparisons of instruments 

 was carried out at the Department's station in the grounds of the 

 Colombo Observatory. The use of the observatory was freely offered 

 by the surveyor-general and by the director of the observatorj", IMr. 

 Bamford; the ready cooperation thus received and courtesies shown 

 by the various officials greatly facilitated our work. 



The vessel left Colombo on July 24, the course being set for a point 

 somewhat southwest of Java and thence generally southward to about 

 latitude 33° south and longitude 85° east. Thence the vessel followed 

 a track generally to the east and arrived at Fremantle on August 31. 

 For 9 days during this part of the cruise continuous calm was 

 experienced and the auxiliaiy power had to be used for a distance of 

 800 miles to get through the belt. Declination observations were 

 made at over 50 stations. 



The complete program of intercomparisons of ship's mstruments 

 was carried out at Fremantle. The land instruments aboard the 

 Carnegie were also compared with the standards at the Watheroo 

 Magnetic Observatory of the Department. 



Upon the completion of the work at Watheroo, the Carnegie left 

 Fremantle October 1, and followed a course to the south of Australia, 

 reaching latitude about 50° south and longitude about 140° east. 

 Thence the course was shaped to the northeastward for Lyttelton, 

 New Zealand, passing through Cook Strait between North Island and 

 South Island. Lyttelton was reached October 20 and on October 21 



