{TAIL ~ a force measurement device} for obtaining a measurement indicative of {HEAD ~ the frictional force} resisting movement of the sample as it is moved in said first direction 
{ TAIL ~ a force measurement device } for obtaining a measurement indicative of { HEAD ~ the frictional force } resisting movement of the sample as it is moved in said first direction
TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH