544 



JOSEPH BAKRELL 



than the real horizontally extended bodies in order to produce the 

 same deflections as those observed. 



The question arises then as to the real form and mass of the 

 bodies interpreted here as spheres. The supplemental data at hand 

 yield evidence only in regard to No. 2. This, however, is the great- 

 est of the six outstanding masses in this series. The supplemental 

 data consist of observations on gravity anomalies at three localities 

 whose distances from the epicenter of No. 2 are as follows: 



Relations of Gravity Anomalies to the Epicenter of Mass No. 2 



a, 47 km. S. E. +0.031 



b, 163 km. E. —0.009 



c, 250 km. N.N.W. —0.029 



Now the curves for Fv and also for the Fy component of Fh show 

 with increasing distance from the epicenter a rapid fall from the 

 maximum value. These effects of the gravitative force due to out- 

 standing masses are consequently markedly local and the nature 

 of the mass No. 2 must have a distribution such as to account for 

 the anomaly of -f-0.031 at 47 km. from the epicenter. The inter- 

 pretation must not give a form which will exert marked influence 

 upon those points distant 163 and 250 km. The dominating influ- 

 ence of mass No. 2 on the value of Fv appears therefore to be con- 

 fined to distances within 125 or 150 km. of the epicenter. But the 

 two limiting spheres of mass 2 . 5M and 2 . 9M respectively give the 

 relations shown in the first two lines of Table XXIX. 



TABLE XXIX 



Interpretation of Mass No. 2 



The interpretation of the deflections as due to spheres gives a 

 gravity anomaly at the epicenter of the sphere between four and 

 six times larger than the largest yet observed in the .United States. 



