456 



Special Reports 



Table 16G. Results of Comparisons at the Samoa Obsei-vatory, 1904 to 1911. 



No. 



Date 



Ele- 

 ment 



Values obtained 1 



I. M. S. 



Samoa 



No. 



seta 



I. M. S.- 

 Samoa 



Weight 



Place of 

 comparison 



6 



7 



8 



9 



10 



11 



12 

 13 

 14 

 15 

 16 

 17 

 18 



Oct., 1904 



Dec, 1905 



Dec, 1906 



Sept., 1907 



May 3, 1906... 

 Mar. 5, 1907. . . 

 Mar. 6,7, 1907. 

 May 5, 6, 1911. 



D 



D 



D 

 D 

 D 

 D 

 D 



+9 

 +9 

 +9 

 +9 



36.4 

 34.0 

 34.5 

 45.2 



+9 

 +9 

 +9 

 +9 



37.8 

 39.9 



40.4 

 50.3 



10 



-1.4= 

 -5.9 

 -5.9 

 -5.1 



2.0 



1.0 

 0.5 

 0.5 



Weighted mean value of (I. M. S. Samoa). 



-2.8 



4.0 



1904-1909 



Nov. 20, 1904. . 

 May 3, 1906. . . 

 Mar. 5, 1907. . . 

 Mar. 6, 7, 1907. 

 May 5, 6, 1911. 



H 

 H 

 H 

 H 

 H 

 H 



20079 

 35694 

 35683 

 35698 

 35535" 



20078 

 35683 

 35682 



35539 



+ 0.00008// 

 +0.00005//' 

 +0.00031//! 

 +0.00003H 

 +0.00017// 

 + 0.00017// 



2.0 

 1.5 

 0.5 

 0.5 

 1.0 

 0.5 



Weighted mean value of (I. M. S. Samoa). 



+0.00014// 



6.0 



1904 (?) 



May 3, 4, 8, 1906 



May 3, 4, 1906 



May 3, 4, 1906 



Dec 8, 9, 10, 13, 1906. 



Mar. 5, 6,7, 1907 



Mar. 5, 6, 7, 1907 



? 



2M 

 5 

 4 

 4 



+ 

 + 1 



+ 1 

 

 4 1 

 + 3.2 

 4 3.2 



2.0 

 0.5 

 1.0 

 1.0 

 1.0 



0.5 



Potsdam 



Samoa, N 



Potsdam 

 Samoa, N 

 Samoa, W 

 Samoa, // 

 Samoa, N 



Potsdam & Samoa 

 Cheltenham 

 Samoa, A' 

 Samoa, W 

 Samoa, Ha 

 Samoa, N 



Potsdam 

 Samoa, N 

 Samoa, E 

 Samoa, JV a 

 Samoa, JV 

 /Samoa, // 

 [Samoa, W 



Weighted mean value of (I. M. S. Samoa). 



+0.7 



6.0 



' All values for Samoa apply for iV or are referred to that station by the station-differences indicated in Table 16H ; 

 all Observatory values are based on the adopted Samoa standards, viz, Tesdorpf magnetometer No. 2025 for declination and 

 horizontal intensity and Schulze earth-inductor No. 2 for inclination. 



- Cf. Res. Dep. Terr. Mag., Vol. II, p. 257. 



3 Small weight account suspected local disturbances because of construction work. 



' Rain and mosquitoes greatly disturbed all observational work on May 5 and 6, 1911. 



See Res. Dep. Terr. Mag., Vol. II, p. 252. 



Rejecting an apparently erroneous value 354847 determined at ll k 25 m on May 6, 1911. 



material used in one of the piers (see Vol. II, pp. 256-257, and present volume, p. 453) 

 only a general summary of these results is given in Table 16G. Since in most of these 

 earlier series it was not always possible to have magnet systems of the several instru- 

 ments at the same height above corresponding piers, small weights are given the results 

 in Table 16G when combining them with others. 



With reference to the various stations used, and to adopted values of station-differ- 

 ences, Dr. Angenheister in the report accompanying his letter of February 27, 1917, 

 utilizing all comparison data through May 1915, says: 



"During 1905 and 1906 all observations were taken on the single stone pier in the old al iso- 

 late observatory. In the beginning of 1907 the old absolute house was replaced in the same loca- 

 tion by a new house. In tearing down the old house an iron chisel was found in the roof between 

 the sheathing and the roofing felt, just above the pier; this made observed values of negative incli- 

 nation 3'.5 too small. (Correction has been applied accordingly to results obtained in 1905 and 

 1906.) There are 4 piers in the new absolute observatory, viz, N, SE, SW, and SE corner-pier. 

 The galvanometer for inductor observations is mounted on the SE curner-pier. Inclination is 

 observed on SE, oscillations for horizontal intensity are observed on SW, and deflections for hori- 

 zontal intensity and declination are observed on pier N. The main pier, N, occupies the same 

 place and has the same height as that of the old pier in the old absolute observatory. Its upper 

 half since 1907 is made with lava-free, white sand; the old pier was made of sea sand containing 

 lava. All results should be referred to .V. The differences (NSW) = +3.5y, for horizontal 



