This enables the magnet to produce a maximum force on molecules that are furthest from the magnet axis with {HEAD ~ proportionally smaller forces} produced approaching {TAIL ~ the axis}, effecting first collimation and then focusing to a small circular area those molecules having magnetic moments aligned in the proper manner with the magnetic field 
produced approaching
This enables the magnet to produce a maximum force on molecules that are furthest from the magnet axis with { HEAD ~ proportionally smaller forces } produced approaching { TAIL ~ the axis } , effecting first collimation and then focusing to a small circular area those molecules having magnetic moments aligned in the proper manner with the magnetic field
OTH OTH OTH 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 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