▁ 1 8 8 0 s ▁and ▁ 1 8 9 0 s , ▁both ▁the ▁power ▁of ▁naval ▁art illery ▁and ▁the ▁speed ▁of ▁war ships ▁had ▁further ▁increased , ▁leading ▁to ▁further ▁invest ment ▁in ▁the ▁castle ▁between ▁ 1 8 8 8 ▁and ▁ 1 8 9 3 . ▁The ▁keep ' s ▁magazine , ▁which ▁could ▁hold ▁up ▁to ▁ 2 , 2 5 0 ▁shell s , ▁was ▁rein for ced ▁with ▁concrete ▁and ▁the ▁south ▁bast ion ▁of ▁the ▁old ▁castle ▁was ▁filled ▁in ▁with ▁sh ing le ▁and ▁concrete ▁for ▁additional ▁protection . ▁New ▁ 6 - p ound er ▁( 2 . 7   kg ) ▁quick - f iring ▁guns ▁were ▁installed ▁in ▁a ▁battery ▁on ▁the ▁end ▁of ▁the ▁east ▁wing , ▁supported ▁by ▁machine ▁guns , ▁to ▁enable ▁them ▁to ▁target ▁fast ▁moving ▁vessels , ▁particularly ▁the ▁new ▁tor ped o ▁boats . ▁Further ▁emp lac ements ▁for ▁ 1 2 - p ound er ▁( 5 . 4   kg ) ▁guns ▁followed , ▁including ▁one ▁on ▁the ▁top ▁of ▁the ▁keep . ▁ ▁Thomas ▁Clar ke , ▁one ▁of ▁the ▁executed ▁leaders ▁of ▁the ▁E aster ▁R ising ▁in ▁Dublin ▁in ▁ 1 9 1 6 , ▁was ▁born ▁in ▁Hur st ▁Castle . ▁▁ 2 0 th - 2 1 st ▁centuries ▁▁ ▁By ▁the ▁First ▁World ▁War , ▁the ▁guns ▁installed ▁at ▁Hur st ▁Castle ▁in ▁the ▁ 1 8 7 0 s ▁were ▁ob sole te .