Chap. 8] 



MAGNETIC METHOD 



387 



For vertical magnetization, the constant C = kL^, where h is the breadth 

 of the magnetized plate, and k the susceptibihty. As in eq. (8-52c), the 

 remanent magnetization Sr may again be substituted for kZq , where it is 

 appreciably greater than the induced magnetization. The vertical in- 

 tensity directly above a two-dimensional plate is AZniax. = 2C/d. The 



4-3 *2 */ -1 =7 ^J -* ~S -f 



Fig. 8-47d. Anomalies of dipping magnet of 90° dip (after Nippoldt). 



following interpretation and depth 

 rules follow from eq. (8-55) : (a) The 

 maximum of vertical intensity and 

 the zero of horizontal intensity 

 anomaly occur directly above the 

 plate; (6) the anomalous vectors in- 

 tersect in the depth of the mag- 

 netized line (in the x'-d plane); 

 (c) the distance of the point where 

 AZ = lAZniax. from the point is 

 equal to the depth; (d) the AH curve 

 intersects the AZ curve at a dis- 

 tance equal to the depth (where 

 AZ = ^AZmax. and where the angle of the anomalous vectors is 45°). 



5. The vertical line doublet corresponds to a vertical magnetized plate of 

 limited depth extent whose lower end is effective. By adding the anoma- 

 lies due to two magnetized lines, 



Fig. 8-48. Magnetized line. 

 (< = 6 in text) 



AH = 2Cx 



Lp2 PlJ 



and 



AZ = 2C 



Lpi PiJ 



(8-56) 



