second coil means for electromagnetically sensing relative proximity and up and down displacement of said projectile in {HEAD ~ terms} of currents induced by {TAIL ~ the mechanical motion} of the said projectile 
second coil means for electromagnetically sensing relative proximity and up and down displacement of said projectile in { HEAD ~ terms } of currents induced by { TAIL ~ the mechanical motion } of the said projectile
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH