



FIGURE 1(a). A TYPICAL OZALID COPY BT PROFILE. NOTE THE SIZE 

 AND SCALE OF THE GRAPH. 



FIGURE 1(b). HYSTERESIS IN A BT PROFILE, CAUSED BY SENSOR 

 MECHANICAL INERTIA. NOTE CORRESPONDENCE 

 BETWEEN "HUMPS AND BUMPS" RECORDED DURING 

 SENSOR DESCENT AND ASCENT. 



