GRAVITATIONAL METHODS 



357 



(e) Finite rectangular prism with vertical and horizontal faces parallel to 

 the axes, bounded by x = Xx and Xo, y = y\ and — yi (^2), z = z^ and Z2. 



jr r- fi V-rr + y- + £^1^ + V y.ri^ + y- ^ Z'^ - y 



Uxz = G-O" loge ^ . =^ 



L V-i'i" + 3'" + ^■r — y V-t'i^ + 3'^ + -^2^ + y 



"+3'1 



+ l0ge 



\/a-2^ + y^ + ^1^ — y \/a'2^ + y- + ^2^ + y 



V-*'2" + 3'^ + s-r + y v^" + y- + ^2^ — y 



B 



Fig. 207. — Relations of blocks and slabs to coordinate axes. Origin coincides with the center of 

 the torsion balance. (Barton, A.I.M.E. Geophysical Prospecting, 1929.) 



