▁fragments ▁that ▁fly ▁in ▁all ▁directions . ▁The ▁use ▁of ▁high ▁explos ives ▁with ▁a ▁fragment ing ▁case ▁impro ves ▁efficiency ▁as ▁well ▁as ▁prop elling ▁a ▁larger ▁number ▁of ▁fragments ▁at ▁a ▁higher ▁velocity ▁over ▁a ▁much ▁wider ▁area ▁( 4 0 - 6 0 ▁times ▁the ▁diameter ▁of ▁the ▁shell ), ▁giving ▁high - expl os ive ▁shell s ▁a ▁vast ly ▁superior ▁battle field ▁le th ality ▁that ▁was ▁largely ▁impossible ▁before ▁the ▁Indust rial ▁Era . ▁World ▁War ▁I ▁was ▁the ▁first ▁major ▁conflict ▁in ▁which ▁HE ▁shell s ▁were ▁the ▁dominant ▁form ▁of ▁art illery ; ▁the ▁failure ▁to ▁adapt ▁inf antry ▁tact ics ▁to ▁the ▁massive ▁increase ▁in ▁le th ality ▁they ▁produced ▁was ▁a ▁major ▁element ▁in ▁producing ▁the ▁gh ast ly ▁sub ter rane an ▁st alem ate ▁conditions ▁of ▁tren ch ▁war fare , ▁in ▁which ▁neither ▁side ▁could ▁risk ▁movement ▁above ▁ground ▁without ▁the ▁guarantee ▁of ▁instant ▁cas ual ties ▁from ▁the ▁constant , ▁ind isc rim inate ▁ha il ▁of ▁HE ▁shell ▁fragments . ▁ ▁One ▁easy ▁comparison ▁between ▁fragment ing ▁HE ▁and ▁sh rap nel ▁shell s ▁would ▁be ▁to ▁imagine ▁a ▁shell ▁of ▁each ▁type ▁standing ▁station ary ▁and ▁base - first ▁on ▁the ▁ground ; ▁a ▁high - expl os ive ▁shell ▁would ▁be ▁equally ▁le th al ▁if ▁det on ated ▁in ▁this ▁state ▁vs . ▁det on ating ▁on ▁impact ▁after ▁being ▁fired , ▁whereas ▁a ▁sh rap nel ▁shell ▁would ▁in effect ually ▁fire ▁its ▁contents