318 CARNEGIE INSTITUTION OF WASHINGTON. 



These comparisons have given additional data for the correlation of 

 magnetic observations made by the various magnetic services. 



Special observations for 5 magnetometers were made at Washington 

 under Mr. Fleming's supervision, to detennine with greater accuracy 

 the moments of inertia of magnets with their suspension arrangements, 

 2 to 4 inertia bars being used for each instrument. The results show 

 desired improvement. To obtain satisfactory values it was found 

 necessary to make not less than 12 determinations of the moment of 

 inertia with each inertia bar. In general the results of these investiga- 

 tions indicate that, when magnets and stiriiips are carefully protected 

 against oxidation and wear, as is the case of the Department's instru- 

 ments, there is little or no change in the moments of inertia during 

 field-work. The one notable exception was magnetometer 19, for 

 which the observations indicate clearly a time-linear decrease between 

 June 1912 and February 1916, of about 0.3 per cent in the moment of 

 inertia. The linear change with time is confirmed by the excellent 

 agreement in the corrections on International Magnetic Standard, 

 determined on different dates at Washington, preceding and following 

 the field-work, when corrections for the change were appUed. 



The investigations of possible changes in the values of the distribu- 

 tion coefficients for different instruments were continued. In general, 

 although the accidental errors of determination are large, the indica- 

 tions are that the coefficients may be considered practically constant 

 while the instruments are in active use, certainly for periods as long 

 as 2 or 3 years. It is found that, in spite of utmost care used in mak- 

 ing magnets, the coefficients do not agree with theoretical values 

 derived from the formula? involving the relative dimensions of long 

 and short magnets. The various underlying causes for the discrepan- 

 cies are under investigation. 



ABSTRACTS OF PUBLICATIONS AND CONTRIBUTIONS TO 

 SCIENTIFIC SOCIETIES. 



List of publications of the Department of Terrestrial Magnetism of the Carnegie Institution 

 of Washington. July 1, 1916. 8°, pp. 16. 



This is the first complete list of publications and contributions to scientific 

 societies by members and associates of the Department of Terrestrial Mag- 

 netism, from the year (1904) of the establishment of the Department to July 

 1, 1916. It is divided into three parts: (A) Papers and Contributions to 

 Scientific Societies 1904-1916, 176 titles; (B) Annual Reports of the Director 

 of the Department of Terrestrial Magnetism, 1904-1915, 12 titles; and (C) 

 Major Publications, 1912-1916, 3 titles. It is proposed to issue a second 

 edition early in 1917, in order to make the Ust complete to the end of 1916. 

 Cross-references and brief explanatory remarks are added to the various 

 titles, whenever necessaiy, for facilitating the use of the list. 



Magnetic declinations and chart corrections obtained by the Carnegie from Dutch Harbor, 

 Alaska, to Lyttelton, New Zeland, August-November 1915. J. P. Ault. Terr. 

 Mag., vol. 21, 15-18 (Mar. 1916). Washington. 



