L. A. Bauer — Gravity Determinations at Sea. 15 



In the first place it is seen that Hecker's mean Ag for the 

 seven points here considered is larger for the 1910 figures than 

 for the 1908 ones — whether the mean is taken with or without 

 regard to sign. Next, the differences on Hayford are in every 

 instance larger quantitatively for the 1910 figures than for the 

 original ones of 1908 except for No. 5. 



Furthermore the difference, Hecker-Havford for station No. 

 2, viz., +0-207 for 1908 and +'256 for 1910, is greater than 

 any residual thus far shown upon Hayford's computed g-'s. For 

 56 pendulum stations in the United States Hayford's computed 

 values differed from the observed ones, on the average, by less 

 than , 02 cm , the maximum difference being 0*091, this occur- 

 ring at Seattle, known to be locally disturbed. Here are the 

 differences for some very disturbed pendulum stations : 



Table IV. — Some Very Disturbed Land Stations. 



Station 



Honolulu 



Mauna Kea (volcano) 



Hachinohe (Japan) 



St. Georges, Bermuda 



Janiestown, St. Helena... 



Sorvaagen, Norway 



Kala-i-Chumb, Turkestan 

 Gornergrat, Switzerland.. 

 St. Maurice, Switzerland 



Height 









above 



Latitude 



Longitude 



Oo-gc 



sea level 









m 







cm 



6 



21° 18' N 



157° 52' W| 



+ 0-053 



3981 



19 49 N 



155 29 W 



+ -184 



21 



40 31 N 



141 30 E 



+ -111 



2 



32 21 N 



64 40 W 



+ -019 



10 



15 55 S 



5 44 W\ 



+ 059 



19 



67 54 N 



13 02 Ei 



+ -147 



1345 



38 27 N 



70 46 E 



- -052 



3016 



45 59 N 



7 46 E 



+ -050 



419 



46 13 N 



7 00 E 



+ -004 



It will be noted that only in the case of two very remark- 

 able stations — the volcano Mauna Kea and Sorvaagen, Norway, 

 Hayford's computed g c differs from the observed g Q by more 

 than - ll and in both of these cases the differences are less than 

 0-2. But Hecker's revised figures of 1910 give five out of 

 seven residuals over 0-1 and two above - 2. Whether Hay- 

 ford's method fails for such deep sea stations as here considered 

 or whether we have thus afforded an indication of the absolute 

 error of Hecker's values, it is not for me to say. It is curious, 

 however, that Hecker's supposedly most correct values (those 

 for 1910) accentuate the differences on Hayford. 



Other detailed examinations made have not revealed any 

 superiority of the 1910 method of adjustment over the pre- 

 vious one. The difficulty with some of the port observations, 

 e.g., at San Francisco, was found to be chiefly due to instru- 

 mental changes (change in thermometer corrections). If the 

 port observations are omitted, as Hecker desires, then the mean 

 difference in Ag between his two computations without regard 



