282 CARNEGIE INSTITUTION OF WASHINGTON. 



Those taking chief part in the investigational work of terrestrial 

 magnetism at Washington were: L. A. Bauer, S. J. Barnett, W. J. 

 Peters, J. A. Fleming, J. P. Ault, H. W. Fisk, C. R. Duvall, C. C. Ennis, 

 and H. B. Hedriek. 



For further accounts of above work, see abstracts, pages 302-3 16. 



MAGNETISM IN GENERAL, 



By December 1919, it is hoped that the non-magnetic building, known 

 as the experiment building and erected under Mr. Fleming's charge 

 on the Department's site at Washington, will be ready for use in special 

 experimental work pertaining to fundamental problems in magnetism. 

 For details of construction, see pages 301 and 302. 



The following chief problems, besides those elsewhere mentioned, 

 have engaged Dr. Barnett's attention during the year: 



(a) The investigation of certain aspects of crystal magnetization. 



(b) Continuation of the experiments on magnet-photography, referred 



to in the annual reports of 1917 and 1918. 



(c) Continuation of the experiments on magnetization produced by 



rotation and rotation produced by magnetization. (The com- 

 pletion of the Experiment Building will furnish exceptional 

 facilities for these important experiments.) 



(d) Method of determining the acceleration of gravity at sea with the 



requisite accuracy. 



Dr. Barnett also gave a course of 26 lectures on theories of magnetism 

 at the Laboratory between September 1918 to June 1919, which course 

 was attended by members of the Department, U. S. Bureau of Stand- 

 ards, and U. S. Patent Office. For further accounts of work done by 

 him, see page 294 and abstracts pages 304-306. 



TERRESTRIAL ELECTRICITY. 



In view of the growing importance of investigations in atmospheric 

 electricity, earth-currents, and polar lights, a Section of Terrestrial 

 Electricity, under the immediate charge of Dr. S. J. Mauchly and as a 

 part of the work of the Division of Experimental Work, was formed at 

 the beginning of the year. The following chief investigations engaged 

 the attention of the section: 



(a) Improved continuous registrations of the electric potential-gradient 



and electric conductivity of the atmosphere in the deck-house on 



the roof of the Laboratory at Washington, 

 (fe) Reduction and discussion of the atmospheric-electric observations 



at Lakin, Kansas, in connection with the total solar eclipse of 



June 8, 1918. (See abstract, p. 307.) 



(c) Methods, instructions, reduction, and discussion of the atmospheric- 



electric observations made by Mr. Wise's party at Sobral, 

 Brazil, in connection with the total solar eclipse of May 29, 1919. 



(d) Improvements in methods and instruments for the atmospheric- 



electric work on the Carnegie. 



(e) Further critical studies of earth-current observations. 



