314 CARNEGIE INSTITUTION OF WASHINGTON. 



rents passing perpendicularly through the Earth's surface. Students 

 of terrestrial magnetism regard this as one of the outstanding questions 

 of the present time, the definite solution of which has an important 

 bearing on theories of some of the Earth's magnetic and electric 

 phenomena. A preliminary investigation on the basis of the most 

 complete data available appears to lead to some positive results and 

 to indicate that possibly 2 to 3 per cent of the Earth's total magnetic 

 field is caused by a system of vertical currents of the kind described 

 (see p. 348). In the planning of the various cruises of the Galilee and 

 of the Carnegie, special consideration was given to obtaining compre- 

 hensive tests of this interesting question in various parts of the Earth. 

 Some further results of these preparatory studies were previously 

 mentioned under "Introductory Remarks." For fuller accounts of 

 these studies see pages 332-333 and 347-351. 



MAGNETISM IN GENERAL. 



Improvements in appliances and methods have resulted in obtaining 

 greater precision in the experiments on magnetization by rotation con- 

 ducted by Dr. S. J. Barnett in the Department's non-magnetic experi- 

 ment building, the completion of which was reported upon last year. 

 The results of the two independent methods (the method of electro- 

 magnetic induction and the magnetometer method) have been brought 

 into better agreement than they were before. Dr. Barnett states 

 (see p. 341) that the present results confirm the result first obtained by 

 the method of electromagnetic induction, namely: Either negative 

 magnetons with a value of the ratio of angular momentum to mag- 

 netic moment, different from that ordinarily accepted for electron 

 rings, are responsible for magnetism, or else positive electrons or 

 magnetons are also involved. The experiments are being continued. 

 It has not yet been possible to go further with the experiments on 

 rotation by magnetization. 



For further details reference may be made to Dr. Barnett's report on 

 pages 340-341 and to the abstracts of his papers and communications 

 to scientific societies on pages 345-346. 



TERRESTRIAL ELECTRICITY. 



The section of Terrestrial Electricity has continued under the charge 

 of Dr. S. J. Mauchly, whose report on pages 333-335 may be consulted 

 as to details. 



The principal activities of the section may be summarized as follows : 

 Reduction of atmospheric-electric observations made aboard the 

 Carnegie and at Washington in the temporary observatory on the deck 

 of the main laboratory of the Department ; studies and improvements 

 of observational methods ; designs of instruments for the atmospheric- 

 electric work at the Department's observatories and for the MacMillan 

 Baffin Land Expedition; study of methods and equipment for polar- 



