Comparisons of Magnetic Standards, 1905-14 



263 



'All values are referred to station A,,,: Am = f'm +397. 

 -These are the vahies obtained with C I. W. No. 3 standardized. 

 25, 30, and 40 cms. were used for each instrument. 



The three deflection distances 



The next series of comparisons will serve further to show the accuracy attainable in 

 such work with field instruments. Magnetometer C. I. W. No. 15 of the tj^pe 1 (6) , described 

 and illustrated in ^'olume I, pp. 2-7, and Plate 3, Fig. 2, was designed and constructed in 

 1910 by the Department of Terrestrial Magnetism for the Meteorological Ser\'ice of Canada, 

 the present owner of the instrument. After all the constants had been caref ullj- determined, 

 by the Department of Terrestrial Magnetism, the magnetometer was compared at Washing- 

 ton with C. I. W. No. 3. This magnetometer (C. I. W. No. 15) has figured in the com- 

 parisons at the Agincourt Observatory (see Table 1 B, series V, p. 215). 



It will be seen that the //-results with C. I. W. No. 15 are given separately for the 

 3 deflection distances, r = 20 cms., r = 25 cms., and r = 28 cms. 



Table 27 C. Results of Declination Comparisons between C. I. W. MagnelometeTs Nos. 3 and 15 at Washington. 



'.Ml values are referred to station Am; .4m = C'ni+19'.S. 



^These are the values obtained with C. I. W. No. 3 standardized. 



