ff rage ▁which ▁she ▁was ▁helping ▁to ▁organ ise . ▁In ▁ 1 9 1 8 , ▁her ▁library ▁was ▁given ▁to ▁the ▁National ▁Union ▁of ▁Women ' s ▁Su ff rage ▁Soci eties ▁( NU W SS ) ▁although ▁B entin ck ▁still ▁took ▁a ▁strong ▁interest . ▁The ▁library ▁is ▁considered ▁her ▁most ▁important ▁legacy . ▁The ▁N U W SS ▁gave ▁the ▁library ▁to ▁the ▁Women ' s ▁( Service ) ▁Library ▁in ▁ 1 9 3 1 . ▁Her ▁collection ▁is ▁considered ▁to ▁be ▁the ▁core ▁of ▁what ▁is ▁now ▁the ▁important ▁Women ' s ▁Library . ▁ ▁Personal ▁life ▁In ▁ 1 8 8 5 , ▁she ▁married ▁an ▁arist ocrat ▁named ▁Frederick ▁Cav end ish - B entin ck ▁( 1 8 5 6 – 1 9 4 8 ). ▁Frederick , ▁a ▁son ▁of ▁the ▁R t . ▁Hon . ▁George ▁Cav end ish - B entin ck , ▁inherited ▁his ▁father ' s ▁deb ts ▁when ▁he ▁died . ▁ ▁His ▁older ▁brother ▁was ▁William ▁George ▁Cav end ish - B entin ck , ▁British ▁Member ▁of ▁Parliament ▁who ▁married ▁the ▁American ▁he ir ess , ▁Elizabeth ▁Living ston ▁( who ▁had ▁two ▁girls ▁but ▁no ▁boys ). ▁T ogether , ▁Ruth ▁and ▁Frederick ▁were ▁the ▁parents ▁of ▁four ▁surv iving ▁children , ▁including : ▁▁ ▁Ferdinand ▁Cav end ish - B entin ck , ▁ 8 th ▁Duke ▁of ▁Port land ▁( 1 8 8 8 – 1 9 8 0 ), ▁who ▁served