oring , ▁they ▁real ised ▁that ▁they ▁had ▁found ▁a ▁new ▁route ▁into ▁Pool ▁Chamber , ▁by pass ing ▁the ▁deep ▁water ▁of ▁the ▁original ▁entrance . ▁ ▁During ▁the ▁ 1 9 0 8 ▁expl or ations , ▁the ▁York shire ▁R amb lers ▁conducted ▁tests ▁to ▁as certain ▁the ▁hydro log ical ▁connections ▁between ▁c aves . ▁They ▁performed ▁a ▁d ye ▁trac ing ▁experiment ▁with ▁flu ores ce in , ▁establish ing ▁a ▁direct ▁hydro log ical ▁connection ▁from ▁the ▁Ag hin ra wn ▁River ▁sink ▁at ▁Mon ast ir ▁cl iff , ▁via ▁Upper ▁C rad le ▁H ole ▁C ave ▁( s itu ated ▁on ▁the ▁south ▁side ▁of ▁C rad le ▁H ole ), ▁to ▁the ▁Cl ad agh ▁Glen ▁res urg ence . ▁While ▁surve ying ▁Lower ▁C rad le ▁H ole ▁C ave , ▁one ▁ca ver ▁sent ▁a ▁floating ▁cand le ▁down stream ▁along ▁the ▁river , ▁until ▁it ▁flo ated ▁under ▁a ▁low ▁ce iling ▁out ▁of ▁sight ▁at ▁the ▁end ▁of ▁the ▁known ▁passage . ▁On ▁plot ting ▁the ▁survey ed ▁passage ▁on ▁a ▁map ▁alongside ▁Mar ble ▁Arch ▁C ave , ▁it ▁was ▁apparent ▁that ▁only ▁ ▁separated ▁the ▁end ▁of ▁this ▁passage ▁from ▁the ▁up stream ▁end ▁of ▁the ▁Grand ▁Gallery , ▁and ▁it ▁was ▁post ulated ▁that ▁a ▁connection ▁between ▁the ▁two ▁might ▁be ▁for ged . ▁▁ 1 9 3 5 – 1 9 3 8 : ▁Sk reen ▁Hill ▁and ▁connections ▁No ▁further ▁expl oration ▁was ▁made