18 Land Magnetic Observations, 1914-20 



Table 4. Inclination Corrections on Adopted International Magnetic Standard for the Period 1914-1920 Concluded. 



Instrument 



Type 1 



Inclination 



Corrections for needle 



Tabular 

 designation 



Correc- 

 tion for 

 compass 



Remarks 



Casella circle 4655 



(a) 



+ 71 to +87 



No. IX 

 + 0'.5 



Earth inductor 2 . 

 Earth inductor 3 . 



Earth inductor 4 . 



Earth inductor 5. 



Earth inductor 6A 



Earth inductor 7. 



Earth inductor 48' 



Magnetometer in- 

 ductor 24 



Magnetometer in- 

 ductor 25 



4(c) 



4(c) 



All values 

 All values 



All values 



All values 



All values 

 All values 

 All values 

 All values 



All values 



Magnetometer in- 

 ductor 26 



Magnetometer in- 

 ductor 27 



Magnetometer in- 

 ductor 28 



4(c) 



4(c) 

 4(c) 



All valuoa 



All values 

 All values 



O'.O 

 -0'.6 



+ 0'.3 



O'.O 



-0'.5 



-O'.l 



O'.O 



-0'.3 



O'.O 



-O'.l 



-O'.l 

 -0'.2 



No. 2X 

 -0'.6 



4655.(127) 

 (See remarks) 



-I'.li 



EI 2 

 EI 3 



EI 4 



EI 5 



EI 6A 

 EI 7 

 EI 48 

 EI 24 



EI 25 



EI 26 



EI 27 



EI 28 



Property of United States Coast 

 and Geodetic Survey. Used 

 during June to Oct. 1914 in 

 Canada and Labrador. Cor- 

 rection for needle 7 deflected 

 by needle 8 of circle 201 in 

 total-intensity work for dips 

 + 76 to + 77 was-l'.l; log- 

 arithm of total-intensity con- 

 stant 3 for needle-pair 7 and 8 

 of 201 was 9.56407. 



Used since July 1916 in Australia. 



Used since June 1914 on cruises of 

 Carnegie. 



Used since 1913 at Mauritius Ob- 

 servatory. Marine type, made 

 by Department of Terrestrial 

 Magnetism, adapted for land 



Used during Sept. 1916 to Sept. 

 1917 and since Feb. 1919 in 

 South America, and during 

 May to June 1918 in United 

 States. 



Property of Captain Roald 

 Amundsen. 



Used since Oct. 1919 on cruise of 

 Carnegie. 



Standard instrument of the De- 

 partment since 1907. 



Used during Jan. 1914 to Feb. 

 1915 in Australia, during July 

 1917 to July 1918 in China, and 

 during May to July 1919 in 

 Africa. 



Used for land work on cruises of 

 Carnegie during June 1914 to 

 June 1918 (including extended 

 field work in South America 

 during May to Nov. 1917) and 

 since Sept. 1919, and during 

 June to July 1919 in United 

 States. 



Used during June 1915, Sept. to 

 Nov. 1917, May to June 1918 

 in United States, and during 

 July 1915 to March 1916 in 

 Europe. 



No field use. 



Used during Jan. to Aug. 1917, 

 and March to Aug. 1919 in 

 South America. 



1 For explanation of types, see p. 6. 



'- Compass attachment of circle 201 was used with circle 4655 during June to October, 1914. 



' After the breaking of pivot of needlo 8 of circle 201 on October 8, 1914, only deflection observations were possible; the logarithm of the 

 total-intensity deflected-dip constant used for the few stations following was 9.45415 at 20 C, using the effect of temperature coefficient on the 

 logarithm as an increase of 0.00010 for a decrease of 1 C. 



i Wild-Eschcnhagen type, as made by Toepfer and Son, with Department modifications. 



8 Marine type, made by the Department of Terrestrial Magnetism. 



* Wild-Eschenhagcn type, as made by Schulze. 



' Designated by maker's number; this instrument is serial number 1 of the Department. 



