{HEAD ~ A method} of determining the level of {TAIL ~ a material surface} in a confined space, from a position above said surface, using an ultrasound transducer positioned above said surface, said method including the steps of: 
{ HEAD ~ A method } of determining the level of { TAIL ~ a material surface } in a confined space , from a position above said surface , using an ultrasound transducer positioned above said surface , said method including the steps of :
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH