▁It ▁was ▁originally ▁required ▁that ▁membership ▁of ▁the ▁Se an ad ▁be ▁limited ▁to ▁those ▁who ▁were ▁over ▁ 3 5 ▁who ▁would ▁serve ▁ 1 2 - year ▁terms . ▁The ▁Constitution ▁( Am end ment ▁No . ▁ 8 ) ▁Act , ▁passed ▁on ▁ 2 5 ▁October ▁ 1 9 2 8 , ▁reduced ▁the ▁minimum ▁age ▁of ▁el ig ibility ▁for ▁Se an ad ▁members ▁to ▁ 3 0 ▁and ▁the ▁Constitution ▁( Am end ment ▁No . ▁ 7 ) ▁Act , ▁passed ▁on ▁ 3 0 ▁October ▁ 1 9 2 8 , ▁reduced ▁the ▁term ▁of ▁office ▁of ▁sen ators ▁to ▁ 9 ▁years . ▁ ▁Today ▁inc arn ations ▁of ▁the ▁modern ▁Se an ad ▁are ▁given ▁a ▁new ▁number ▁after ▁each ▁sen atorial ▁election . ▁Thus , ▁the ▁current ▁Se an ad ▁elected ▁in ▁ 2 0 0 7 ▁is ▁known ▁as ▁the ▁' Tw enty - third ▁Se an ad '. ▁This ▁was ▁not ▁the ▁custom ▁during ▁the ▁Irish ▁Free ▁State ▁because ▁the ▁Se an ad ▁was ▁elected ▁in ▁stages ▁and ▁therefore ▁considered ▁to ▁be ▁in ▁permanent ▁session . ▁However , ▁as ▁a ▁gesture ▁of ▁continu ity ▁with ▁its ▁prede cess or , ▁the ▁first ▁Se an ad ▁elected ▁after ▁ 1 9 3 7 ▁is ▁number ed ▁as ▁the ▁' Second ▁Se an ad '. ▁The ▁Se an ad , ▁despite ▁the ▁occurrence ▁of ▁three ▁sen atorial ▁elections ▁before ▁its ▁abol ition , ▁is ▁considered ▁to ▁have ▁been ▁a ▁single ▁Se an