CORE ORIENTATION 69 



rod e is borne by two rectangular shoulders through the 

 internal housing by means of stuffing boxes or friction 

 sockets in the base plate. These lugs are double armed 

 and are connected by a right-angled rod k connected to 

 a lever v through the arm w to the magnet needle. The 

 upper lever is so arranged that when descending the rod e 

 moves its inner arm downward and the outer one upward. 

 In this way k is in tension, pulling, and the forked end of 

 lever w presses down a plate m which touches a leather 

 based rod n. As soon as m is let down the spring jp presses 

 against it and prevents it retreating. The leather ring o 

 now lies on three teeth in the head of the needle and thus 

 holds it fast in its natural north position. 



In order to detect the presence of a magnetically dis- 

 turbed region the precaution is taken of placing another 

 needle about 30 in. below the first one and operated 

 simultaneously with it. From their difference of directions 

 the presence of a magnetic disturbance can be recognized 

 and so a true orientation can be made. 



Heine's stratameter is a simple, sure and easily manip- 

 ulated apparatus well fitted for its task. It is insensitive 

 to water penetration. Thus sand and the like can not enter 

 to hinder the action of the finer parts, and, moreover, these 

 parts are easily accessible for inspection and cleaning. 

 It is very convenient to operate, since it does not interfere 

 with the ordinary working processes of the borehole. The 

 apparatus is inserted in the rods once and for all, it being 

 only necessary to drop in the ball and observe the rinsing 

 pump gage when a reading is required; then the core is 

 wrenched off and the whole raised to the surface. It 

 fits the tools and no extra objectionable extractions are 

 needed. Any doubts in the results obtained are due 

 to the same causes as discussed for Gothan's method. 



Of the apparatuses in this class Gothan's apparatus is 

 the greatest time waster and Heine's device one of the 

 greatest time savers. The chief factors operating against 

 Heine's apparatus are 



1. Shocks may cause the arresting pin to function. 



