21 S Reports on Special Researches 



Table 2B. Results of Dediimlion Comparisons at the Algiers Observatory, November-December 1912. 



Local mean time. 



Date 



Declination obtained' 



C. I. W. -Algiers 



From To C. I. W. Ech. I 



I 

 Bru. I Bru. II Ech. I i Bru. I Bru. II 



Remarks 



Dec. 



1912 



Nov. 30 



30 



30 



30 



5 



5 



6 



6 



6 



6 



9 



9 



h m 



10 44 



11 07 

 11 36 

 11 55 



9 39 

 9 59 



13 51 



14 02 

 14 18 

 14 29 



14 21 



15 06 



h m 



10 53 



11 16 



11 45 



12 04 

 9 48 



10 08 

 14 00 

 14 11 

 14 27 

 14 38 



14 55 



15 15 



-11 41.4 

 41.9 

 42.4 

 42.1 

 38.7 

 39.3 

 39.1 

 38.6 

 38.8 

 38.3 

 39.0 

 38.7 



-11 39.4 



-2.0 



40.8 



-11 38.8 

 40.1 



38.8 

 38.3 



-11 40.0 

 40.3 



-1.9 

 ' -2.1 



-1.3 



+0.1 



+0.8 



.37.7 

 38.0 



39.1 

 39.0 



+0.1 

 +0.3 



Hence mean values; C. I. W. Alsiers (Echa.ssoux I). 

 C. I. W. Algiers (Brunner I). . . 

 C. I. W. Algiers (Brunner II). . 



+0.3 



-0.3 

 -0.3 



-1.0 



-1.1 

 -0.3 



C. I. W. at M; 

 Brunner at O. 



C. I. W. at M; 



Echas.soux at O. 



p. I. W. at O: 

 Brunner at M. 



p. I. \V. at O: 



Echassoux at M. 



-1.4 



'All values are referred to .station O; = M 3'.6. 

 Table 2C. Rrsulls of Horizontal-Intensity Comparisons at the Algiers Observatory, November-December 1912. 



'All are referred to station 0;0 = M for comparisons with Echassoux magnetometer, whereas for Brunner magnetometer 

 = Af +24.6y. The cause for this discrepancy in the station-difference as shown by the two different magnetometers is not 

 at present known. Owing to the fact that, in each set of compari.sons, the observers exchanged stations, any error in the 

 assumed station-difference is eliminated in the final result for the correction of the Echassoux or of the Brunner magnetometer 

 on the C. I. W. standard. 



By comparison with the January results, it will be seen that the //-correction of the 

 Echassoux magnetometer (Magnet I) on the C. I. W. standard has been changed, since the 

 remagnetization of the magnets, from 39.87 to +8.57, or from 0.00156// to +0.00033//. 

 The correction for the Biimner magnetometer on the C. I. W. standard, as judged by the 

 limited number of results, is practically the same for both magnets; taking the mean of the 

 two, we have (C.I. W. Brunner, Magnets I and II) = +0.37. The constant for the Brun- 

 ner instrument was determined relative to the standard at Val Joyeux from observations 

 made there on December 6, 1911 ; however, as no corrections were applied to the Observatory 



