Specimen Observations on the Galilee 



57 



From the dip-circle observations given on pages 51-54, four values of the incUnation 

 were obtained. The results in detail, showing the various corrections applied, are given 

 in Table 5. 



Table 5. — Values of the Magnetic Inclination on April 14, 1908, P. M. 

 (Latitude, 5° 41' S; longitude, 99° 55' W.) 



Instrument and method 



D. C. 189, needle 5, regular dip 



D. C. 189, needle 6, regular dip 



D. C. 189, needle 3, deflected dip, long distance. . . 

 D. C. 189, needle 3, deflected dip, short distance . . 



Obs'd 

 Incl'n 



-0.24 

 -0.58 

 -0.28 

 +0.02 



Instr'l 

 Corr'n 



+0.05 

 +0.05 

 -0.14 

 -0.12 



Weighted means. 



Reduced 

 Incl'n 



-0.19 

 -0.53 

 -0.42 

 -0.10 



-0.33 



Deviation 

 Corr'n 



+0.25 

 +0.25 

 +0.25 

 +0.25 



+0.25 



Corr'd 

 Incl'n 



+0.06 

 -0,28 

 -0.17 

 +0.15 



-0.08 



Weight 



The quantities in the column "Instrumental correction" were derived from Table 16, 

 page 69. The deviation-correction + 0?25 is computed on page 92. Next, the 

 weighted mean was taken, giving to each of the values by needle 3 a weight of 1, and to 

 the values by 5 and 6 a weight of 2 each. The resulting value of the inclination is — 0?08, 

 or 0° 05' S, thus showing that the point of observation (latitude, 5° 41' S; longitude, 

 99° 55' W) was at the time practically on the magnetic equator. 



Summary of Results of Observations Made on Course, April 14, 1908. 

 Summarizing, we have the results given in Table 6. 



'Course, WSW; roll, 30°; sea M; weather, be. 



'Course, W for inclination and intensity observations. For the declination observations it was necessary to change the 

 course to WSW in order that the Sun would not be obscured by masts or rigging. Roll, 20° during dechnation observations, 

 and 30° while inclination and intensities were being observed; sea, M; weather, be. 



'This is the combining weight for use when taking the weighted mean of individual values. It is not to be confused 

 with the "weight" which appears in the Table of Results (p. 104). The latter is intended to give an approximate measure 

 of the reliability of a result according to conditions encountered. Thus, to the results on April 14, 1908 a weight of 2 was 

 assigned in the table (see explanation, p. 95). 



'Sea dip-circle 189, needle 5, regular dip. 



'Sea dip-circle 189, needle 6, regular dip. 



•Sea dip-circle 189, needle 3, deflected dip, long distance. 



'Sea dip-circle 189, needle 3, deflected dip, short distance. 



•Sea deflector 2. 



'Sea dip-circle 189, deflection observations, needles 3 and 4, short and long distance. 



'°Sea dip-circle 189, loaded-dip observations, needle 4. 



