200 



DEEP BOREHOLE SURVEYS AND PROBLEMS 



Anderson's Apparatus. — We have had no personal oppor- 

 tunity of examining this method, the full details of which 



Fig. 13S. — Compass and clinometer. 



are not accessible. However, it is known to be another 

 application of the orientated drill-stem method, the survey 



Fig. 139. — Clinometer and coutact drum. 



principle being that of the multiple-photograph method 

 wherein one or more pendulums are photographed for 

 each position. It has been widely and successfully 



