CORE ORIENTATION 75 



the cores on the surface. To the upper portion of the core 

 box a screwed to the boring rods h is secured a plate holding 

 a pipe c, which leaves a space between it and the walls of 

 the core box for rinsing water. In the center of c are oscil- 

 lating needles d and e supported on their respective gimbals 

 or universal suspensions / and g. Gimbals g are weighted 

 on one side by weight h, causing e to incline. Above d 

 and below e are cork pistons i moved by springs j toward 

 the needle points of d and e. The cork disc i is held by rod 

 k allowing d to oscillate freely and carries an arm lever / 

 rotatable about the long axis of the apparatus, the lower 

 end of this lever holding another arm m by means of rod c 

 to actuate the lower cork plunger i. 



Under the top plunger i is a gunlock trigger-releasing 

 device actuated by rod n operating springs j which press 

 the cork pistons i against the points of pendulum needles d 

 and e. Needle d is used for indicating the dip of the bore- 

 hole and e for the lateral deviation due to the action of 

 weight h. To facilitate this the cork discs i are faced with 

 paper scales on which the needle points prick holes. As 

 electric cables can not be introduced into 

 the hole during boring, the positions of 

 the indicating needles are fixed by a 

 messenger weight dropped in releasing the 

 above device from n. The movement 

 relative to the meridian is taken with 

 respect to a mark made on the core 

 box. 



In core boring the needles are fixed before wrenching 

 off the core; then the core is extracted and the core box 

 arranged on the surface in such a manner that it is slightly 

 inclined and a definite mark arranged on the meridian. 

 The cork pistons i are withdrawn and the needles released, 

 taking up a position in accordance with the inclination 

 of the core box. After the needles come to rest pistons i 

 are again released, and the new position of the needles, in 

 which the scale of the apparatus coincides with the merid- 

 ian, is recorded. Thus, as shown in 40a, we get the points 



