DEPARTMENT OF TERRESTRIAL MAGNETISM. 305 



BUILDING WORK AT WASHINGTON. 



Various mutters in connection with the final equipment of the 

 non-magnetic Experiment Building, remaining undone last year, were 

 completed. These included design and installation of non-magnetic 

 shades and supports, installation of lead sash-weights, installation of 

 screens, and miscelLineous matters. The steam and water pipes in 

 the tunnel between the main laboratory and the experiment Building 

 were covered with asbestos pipe-covering. The necessary extension of 

 the switchboard in the main laboratory for the Experiment Building 

 was completed. Two views of the Experiment Building are shown here- 

 with. 



The main laboratory, Standardizing Magnetic Observatory, and the 

 two frame auxiliary observatories have been repainted and repairs 

 were made as necessary. A new 60-volt storage-battery was assembled 

 in the batterj^-room. Repaii's were made on the macadamized road- 

 ways on the site, as they had been badly damaged by the unusually 

 severe vreather of the past vrinter. Some additional grading was done 

 about the Experiment Building and site, drains for storm-water were 

 provided, and a rough roadway to the east side of the site from the 

 rear of the foundry was made. 



Messrs. S. W. ]Malvin and T. S. Perry looked after the care of the 

 grounds and did most of the improvement work about the site, while 

 Mr. P. E. Brooke was caretaker and night watchman. 



DIVISION OF EXPERIMENTAL WORK.i 



Near the end of 1919, the prospects of occupying soon the Experi- 

 ment Building, for work on the construction and equipment of which 

 the di\'ision continues under great obligations to Mr. Fleming, became 

 such that it was necessary to abandon for the time other work which 

 had been started and to devote all the attention possible to the experi- 

 ments on the relations between magnetization and rotation, and to the 

 sine galvanometer, the superintendence of the construction of which 

 devolved upon the chief of the division in December. 



The Experiment Building was partially occupied in March 1920 

 and a magnetic surve}-- (all elements) was made with the assistance of 

 Messrs. Wallis and Sterling. The results of this survey showed that 

 the desired uniformity of magnetic field within the building had been 

 amply secured. The construction of piers and the mounting of the 

 apparatus then began, and a great deal of progress has been made with 

 the help of Mr. Kotterman and Mr. Huff, whose services became avail- 

 able for instrumental work a little later. (See views of Experiment 

 Building herewith). 



Experiments on magnetization by rotation. — These are in progress and 

 are made by the two general methods described by the writer in the 



'From the report of the chief of the division, S. J. Barnett. 



