The capillary is circular in cross section, this being obtained by drilling or extrusion of {HEAD ~ a cylindrical bar} made of {TAIL ~ dielectric material} 
made of
The capillary is circular in cross section , this being obtained by drilling or extrusion of { HEAD ~ a cylindrical bar } made of { TAIL ~ dielectric material }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL