In individual cases, the strength can be increased by admixing {HEAD ~ graphite} with {TAIL ~ the powder}, although even this should be avoided as far as possible 
with
In individual cases , the strength can be increased by admixing { HEAD ~ graphite } with { TAIL ~ the powder } , although even this should be avoided as far as possible
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH