230 



JOSEPH BARRELL 



Fig. 6 shows the curves for R=i. For any other value of R 

 the curves would be the same in form, but the scales of ordinates 

 and abscissas would be changed. These curves may be used 

 therefore in a general way. 



AUrachon on A by poinhs on verHcol line 

 shoujnby abscissas on the verHcal line. 

 Horizonral Verficol 

 component R componentry 



R=,25 R..50 K=1.0C 



Combined attractions of I and in upon points on the 

 horizontal line.shoiun by ordinates on the horizontal line 



Scale of distance. 



1.00 



Horizonfol Gomponent Fh 



Sum of I and M 



Diff. of 1 andm 

 Verticol component Fy 



5unri of I and [11 



Diff. of 1 and 111 



Fig. 6 Fig. 7 



Fig. 6. — Curves showing relative attraction of all points on the vertical line upon 

 a point at distance R = i. 



Fig. 7. — Combined attractions upon all points on the surface by unit masses of 

 like and unlike signs at I and III of Fig. 6. 



The table shows that if unit masses at II and III have the same 

 sign the horizontal component, Fh, for the sum of their attractions 

 at o. 25/? will be i .95, at R it will be i . 23, which is 63 per cent of 

 the value at 0.25/^. If the unit masses have unlike signs the 

 horizontal component of their difference at o. 2^R will be 0.93, at R 

 it will be 0.21, which is but 23 per cent of the value at 0.25^?. 

 The vertical component, Fv, due to the sum of the masses at 0.2 5/? 

 is 4.40; at R is 0.74. The vertical component due to the difference 

 at 0.25^? is 1.35; at jR is 0.02 and of opposite sign. It is noticed 

 that the gravity anomaly diminishes rapidly with increasing 

 horizontal distance from these two masses and passes through 

 zero. The deflection of the vertical first increases sharply and 



