406 



Special Reports 



rotation may be precisely oriented in the magnetic meridional plane for each observation. 

 The C.I.W. instrument used was the inductor attachment of magnetometer-inductor 

 C.I.W. No. 26. The correction on International Magnetic Standard" for C.I.W. No. 26 

 was O'.l, dip of the north-seeking end of the needle below the horizon being reckoned 

 as positive. 



On January 4, observations were discontinued because of a severe magnetic storm. 

 The first observations with C.I.W. No. 26 on the morning of January 5 were erratic, 

 probably because of slight looseness of the coil in its bearings, and have been omitted, 

 therefore, in Table 2D. 



Table 2D. Results of Inclination Comparisons at the Cheltenham Observatory, 1917. 



1 It is assumed that the station-differences are negligible. 



Series III, 1918. 



This series results indirectly through the comparison during March 12 to 16, 1918, 

 of Cooke magnetometer No. 40, property of the United States Coast and Geodetic 

 Survey, with C.I.W. standard magnetometer No. 3 at Washington, D. C, and its 

 comparison during February 13 to 27, 1918, with C. & G. S. standard magnetometer 

 No. 20 at the Cheltenham Observatory. At Cheltenham the mean from 12 direct 

 comparisons in declination on February 18 and 25 was: 

 (a) Cheltenham -C. & G. S. No. 40= -0'.2I. 



See Res. Dcp. Terr. Mag., Vol. II, pp. 270-273. 



