430 APPENDICES 



some little practice, however, the observer will find an ordinary pocket- 

 compass quite good enough for all his requirements. 



In the combined compass and clinometer here illustrated a pendulum 

 hangs perpendicularly from the central point which carries the needle, 

 and indicates the number of degrees the straight-edge or base, attached 

 to the side, deviates from the horizontal. In the illustration the base 

 being level, the pendulum points to zero. One advantage of this little 

 instrument is that the straight-edge can be applied either to the upper 

 or under side of a bed. Or if we are taking the angle of dip from a little 

 distance, and holding the instrument between the eye and the angle to be 

 measured, it is obviously immaterial whether the straight-edge occupies 

 the position shown in the illustration or is inverted. 



