110 



DEEP BOREHOLE SURVEYS AND PROBLEMS 



at a definite instant and drawing the same out. The 

 immersion and extraction are effected by clockwork, which 

 at the same time actuates the arrest of a magnetic needle. 

 In Fig. 60 the casing may be screwed off into two parts 

 a and h, and they are separated by a cross floor c. In the 

 upper part are the motion apparatus and the immersion 



FIT 



:^^p, 



Fig. 59. 



Fig. 60. — Meine's apparatus. 



body. The lower part is filled with an etching or coloring 

 fluid. The clockwork E stands on plate P which is sup- 

 ported on three legs d, and on the upper cover plate of the 

 clockwork a strap S carries a magnetic needle N. The 

 spring of the clockwork moves a drive of three gear wheels 

 i, ii and 12 and a toothed rack is which carries the immersion 

 body. This arrangement causes the rack either to descend 



