RESEARCH BUILDINGS OF DEPARTMENT OF TERRESTRIAL MAGNETISM. 



By L. A. Bauer and J. A. Fleming. 

 INTRODUCTORY REMARKS. 



The Department of Terrestrial Magnetism, from its establishment on April 1, 1904, 

 until the latter part of February 1914, was housed in rented quarters at Washington, D. C, 

 for the greater time in the Ontario Apartment House, located in the northwest suburban 

 section of the city. With the rapid development of the work of the Department and the 

 requisite increase in the personnel, and because of the estabhshment, in January 1908, of a 

 shop for the construction of new and improved instruments, additional quarters had to be 

 rented from time to time until, in 1913, 16 rooms were required. During this period it 

 was necessary to carry on the observational and experimental researches, such as the test- 

 ing and intercomparisons of instruments, determination of instrumental constants, experi- 

 mental investigations concerning causes of changes in constants, improvements in instru- 

 ments and methods, etc., under more or less unfavorable conditions, in two non-magnetic 

 huts on a small piece of ground overlooking the Zoological Park, about 300 feet west of the 

 Ontario Apartment House. Owing to the rapid growth of the city to the northwest, street 

 improvements and building operations near the observing huts began in 1910 to threaten 

 seriously the satisfactory continuance of the observational and experimental work. The 

 construction work in the instrument shop was also seriously hampered because of crowded 

 quarters, somewhat unsatisfactory lighting, and the necessarilj' temporary installation of 

 machinery in a large building primarily intended for residential purposes. By this time 

 also the progress made by the Department had brought it to a point where the successful 

 and complete solution of the problems of the Earth's magnetism, and allied subjects, called 

 for a combination of laboratory experimental work with the purely observational work. 



Because of the lack of the necessary laboratory facilities, the work hitherto conducted 

 in the subjects of terrestrial magnetism and terrestrial electricity has been chiefly observa- 

 tional. Thus we have magnetic or electric surveys, which imply the determination of the 

 magnetic and electric elements at suitablj' distributed points over the Earth, with the view 

 of obtaining, as accurately as possible, a knowledge of the Earth's general magnetic or elec- 

 tric condition. Furthermore, at a considerably smaller number of points, there are obser- 

 vatories which register the vai'iations to which the magnetic and electric elements are 

 subject, together with tune and with varying planetary and solar conditions. There are 

 thus in progress magnetic and electric surveys, and in operation magnetic and electric 

 observatories; but no laboratory had as yet been established for the specific purpose of 

 broad, cosmophysical research along both theoretical and experimental lines. The great 

 need of the same happy combination of observational and laboratory facilities which had 

 already proved successful in other sciences, as in astrophysics for example, thus became 

 manifest. Besides the further miprovement and refinement of the instrumental appliances 

 for the observational work, there are manifold problems of fundamental importance open 

 to such a laboratorj^, if properlj' manned and equipped. 



The necessity for permanent quarters was further emphasized by the need of better 

 facilities for the office work and for the work of the investigational staff, as also of fireproof 

 archives for the storage of the accumulated field records and compilations of observational 

 data. 



With these aims in \dew, the Trustees of the Carnegie Institution of Washington made 

 special allotments during 1913 and 1914, amounting to $127,200, to provide the requisite 

 permanent facilities for the investigational work at Washington of the Department of 



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