DEPARTMENT OF TERRESTRIAL MAGNETISM. 319 



the ship's magnetic instruments and those of the Honoluki magnetic 

 observatory, operated by the United States Coast and Geodetic Survey, 

 by which a correlation with other magnetic observatories and standards 

 will be effected. Every facility for carrying out these comparisons at 

 the observatory was rendered by the observer-in-charge, Mr. W. W. 

 Merrymon. On June 29 and July 3 the Carnegie was swung off Pearl 

 Harbor in about the same locality as that of the Galilee's swing of 1907. 

 The results confirm the large differences which had been indicated by the 

 Galilee swing, between the values of the magnetic elements at the place 

 of swing and at the observatory, and they also give a means of sup- 

 plying an additional determination of the constant A of the deviation- 

 formula for the Galilee at Honolulu. The place of swing can not be 

 surrounded by land stations and hence can not be controlled by land 

 observations. This shows another advantage of a non-magnetic vessel 

 over a vessel with deviations when used in a magnetic survey of the 

 oceans. After all the labor of planning, observing, and swinging ship, 

 and the tedious computations of the deviation-parameters for a vessel 

 having deviations, we are confronted with the fact that hardly one of 

 the few values of A which can be observed during a cruise is wholly 

 above the suspicion of being affected by local disturbance. We can 

 only hope that the effect is neutraUzed in the mean of a number of 

 observations at the different ports available. 



On July 20 the Carnegie reached Dutch Harbor, having sighted the 

 Bogosloff Islands. The report on the sighting of these islands reads: 



"The Bogosloff Islands were seen at a distance of 3 miles at 2 a. m., July 20. 

 There are two islands at present, the eastern one terminating in two high twin 

 peaks ending in sharp points at the top, the western one with one high moun- 

 tain having a broad top." 



On August 5 the vessel started on the long passage of about 8,000 

 miles to Port Lyttelton, New Zealand, where she arrived on Novem- 

 ber 2, 1915. 



The cruise of the Carnegie from Port Lyttelton will be eastward 

 between the fifty-fifth and sixtieth parallels of south latitude. Condi- 

 tions permitting, stops will be made at South Georgia and Kerguelen 

 Islands, and the vessel will eventually return to Port Lyttelton early 

 in 1916, thus completing a circumnavigation of the globe in these 

 southerly regions. The tracks of the Erebus and Terror will frequently 

 be crossed, or followed some distances, during this cruise. Cross- 

 ings will also be made of the tracks of the Discovery and the Gauss. 

 These tracks for the most part lie in regions where the secular changes 

 of the Earth's magnetism, because of the paucity of the data, are not 

 well determined. 



When the Carnegie arrived at Dutch Harbor she had already covered 

 about 10,030 nautical miles of her present cruise in 70 days of sail- 

 ing, at an average of about 143 miles per day. During these 70 days 

 101 values of the magnetic declination and 56 each of dip and intensity 



