296 CARNEGIE INSTITUTION OF WASHINGTON. 



action. It is proposed to fill this tube with an inert gas, above the 

 mercury, and to study its behavior under various conditions of motion 

 in the laboratory, and at the levels of the laboratory and the bottom 

 and top of the Washington Monument, before making any attempt to 

 use it at sea. 



TERRESTRIAL ELECTRICITY. 



The Director's letter announcing the formation of the Section of 

 Terrestrial Electricity to begin with the current year stated that the 

 term terrestrial electricity, as there used, was intended to include (a) 

 atmospheric electricity, {h) earth currents, and (c) polar lights. In the 

 time which has elapsed since the formation of this special section, it 

 has not been possible to devote any time whatever to the last named 

 of the above subjects, and only a very hmited amount could be given 

 to subject (b). The reduction and pubhcation of the atmospheric- 

 electric observations made at Lakin, Kansas, last year, the necessary 

 provisions for the atmospheric-electric work of the Department's 

 eclipse station in Brazil, various matters concerned with plans and 

 equipment for the atmospheric-electric work aboard the Carnegie on 

 her forthcoming cruise, and the operation of the atmospheric-electric 

 observatory on the deck of the laboratory, have occupied practically 

 the entire time of the very limited personnel thus far available, viz, 

 S. J. Mauchly, chief of section; A. Thomson, C. A. Kotterman, and 

 T. C. Kiesel, occasional assistants. 



Lakin Eclipse Observations of June 8, 1918. — The first task assigned 

 to the section was the reduction and preparation for pubhcation of the 

 results of atmospheric-electric observations made at Lakin, Kansas, 

 in connection with the total solar eclipse of June 8, 1918. Because of 

 the work necessary to enable the Department to supply atmospheric- 

 electric data to the United States Signal Corps during the autunrn of 

 1918, and also on account of the subsequent overhauling and improve- 

 ment of the equipment in the deck observatory, it was impossible 

 to begin this work until January. 



Perhaps it should be stated that most of the atmospheric-electric 

 equipment available for use at Lakin was either of the laboratory type 

 or at least better suited for laboratory than field work. This caused 

 both the observational and reduction work to be much more extended 

 and laborious than would otherwise have been necessary, in order 

 that the final results should justify the expense and time of the expedi- 

 tion itself. 



The results of the Lakin atmospheric-electric observations appeared 

 in the March and June 1919 issues of Terrestrial Magnetism and 

 Atmospheric Electricity. In addition, a report on the conductivity and 

 potential-gradient observations was given by Dr. Mauchly before the 

 Philosophical Society of Washington on February 15. (See abstract, 

 pp. 307-308. 



