▁built ▁across ▁the ▁water ▁on ▁the ▁Is le ▁of ▁W ight ▁to ▁provide ▁supporting ▁fire . ▁The ▁old ▁inn ▁was ▁first ▁re used ▁as ▁the ▁g arrison ▁can teen ▁and ▁then ▁demol ished . ▁ ▁The ▁ 1 8 5 2 , ▁the ▁Is le ▁of ▁W ight ▁Electric ▁Company ▁laid ▁a ▁spe cially - arm oured ▁te legraph ▁cable ▁to ▁link ▁the ▁castle ▁with ▁Key h aven ▁on ▁the ▁main land ▁and ▁S con ce ▁Point ▁on ▁the ▁island ; ▁two ▁years ▁later , ▁the ▁Electric ▁Te legraph ▁Company ▁linked ▁the ▁castle ▁to ▁South am pton . ▁Hur st ▁used ▁flags ▁to ▁pass ▁on ▁te legraph ic ▁messages ▁to ▁and ▁from ▁sh ipping ▁entering ▁the ▁Sol ent . ▁▁ 1 8 5 9 – 9 9 ▁▁ ▁Rap id ▁adv ances ▁in ▁military ▁technology ▁made ▁the ▁new ▁def ences ▁ob sole te ▁before ▁the ▁end ▁of ▁the ▁de cade . ▁The ▁introduction ▁of ▁rif led ▁b ree ch - loading ▁guns , ▁capable ▁of ▁firing ▁explos ive ▁shell s , ▁and ▁the ▁construction ▁of ▁arm our - pl ated ▁war ships ▁left ▁Hur st ' s ▁guns ▁and ▁fort ifications ▁in ade qu ate . ▁F ears ▁grew ▁in ▁ 1 8 5 9 ▁that ▁France ▁might ▁in va de ▁England , ▁potentially ▁in ▁a ▁surprise ▁attack . ▁A ▁ 1 8 5 9 ▁Royal ▁Commission ▁recommended ▁that ▁Hur st , ▁as ▁one ▁of ▁the ▁key ▁for ts ▁protect ing ▁Port sm outh , ▁should ▁be ▁upgrad ed ▁as ▁a ▁matter ▁of