DEPARTMENT OF TERRESTRIAL MAGNETISM. 319 



Cruise of the Carnegie from Lyttelton, New Zealand, to South Georgia, December G, 1915, 

 to January 12, 1916. J. P. Ault. Terr. Mag., vol. 21, 2&-27 (Mar. 1916). 

 Washington. 



Cruise of the Carnegie from South Georgia to Lyttelton, New Zealand, January 14 to April 1, 

 1916. J. P. Ault. Terr. Mag., vol. 21, 103-106 (June 1916). Washington. 



Magnetic decUnations and chart corrections observed on the Carnegie from Lyttelton, 

 New Zealand, to South Georgia, and thence to Lj^ttelton and Pago Pago, Decem- 

 ber 1915-June 1916. J. P. Ault. Terr. Mag., vol. 21, 109-116 (Sept. 1916). 

 Washington. 



These four papers by J. P. Ault, in command of the Carnegie, pertain to 

 observations made aboard the vessel, 1915-16, and to experiences encountered 

 on a circumnavigation voyage in the sub-Antarctic regions, December 6, 1915, 

 to April 1, 1916. (See pages 297-314.) 



Status of magnetic surveys in South America by the Carnegie Institution of Washington. 

 L. A. Bauer. (Abstract of paper presented before Section II, Second Pan- 

 American Scientific Congress at Washington, December 28, 1915; printed by the 

 Congress.) 



In response to the invitation received through the secretary-general of the 

 Second JPan American Congress, the author presented before Section II of 

 the Congress a summary of the work of the chief magnetic surveys conducted 

 in South America, chiefly during 1908 to 1915, by the Department of Terres- 

 trial Magnetism of the Carnegie Institution of Washington. Ten separate 

 expeditions have been sent out, the stations at which the magnetic observa- 

 tions were made numbering 493. About 10 per cent of this number are 

 repeat stations; that is, stations at which observations have been made in 

 various years, either by others or by the Department of Terrestrial Mag- 

 netism. Thus, magnetic data for determining both the distribution of the 

 magnetic elements, and their changes from time to time are obtained. 



Every country in South America is represented in the list of stations, 

 though the number of stations in the different countries varies considerably. 

 Thanks to the very cordial cooperation being received from every organiza- 

 tion in South America engaged in securing magnetic data, it has been j^ossible 

 to cany out effectively the published plan. This plan is not to duplicate 

 but to supplement the work being done well by other organizations, so as to 

 complete in the most expeditious manner possible the task of a general mag- 

 netic survey of the Earth. 



The magnetic stations of the Carnegie Institution of Washington are 

 densest in countries of South America not possessing a magnetic service. 

 In the two countries, Argentina and Brazil, which are actively carrjdng on 

 magnetic surveys, the Institution's work could be restricted in extent. 



A special point, however, has been made of obtaining, at various times, 

 comparisons of the Institution's magnetic standards with those of the other 

 countries. In this way it has become possible to reduce all the recent mag- 

 netic data in South America to the same set of standards, with a degree of 

 accuracy sufficient for both theoretical and practical purposes. 



Some of the Institution's magnetic expeditions have been geographic 

 achievements as well as contributions to the advancement of knowledge of 

 the Earth's magnetism. In addition to the three magnetic elements (the 

 magnetic declination, the magnetic inclination, and the intensity of the mag- 

 netic force), the parties obtain the geographic position of their stations with 

 an accuracy commensurate wdth the purpose, as well as general geographic 

 information. 



