▁latitude ▁of ▁the ▁North ▁P ole . ▁A ▁w ides p read ▁manual ▁in ▁the ▁ 1 8 th ▁century ▁was ▁N avig atio ▁Britannica ▁by ▁John ▁Bar row , ▁published ▁in ▁ 1 7 5 0 ▁by ▁March ▁& ▁Page ▁and ▁still ▁being ▁advert ised ▁in ▁ 1 7 8 7 . ▁ ▁Isaac ▁Newton ▁invent ed ▁a ▁reflect ing ▁quadr ant ▁around ▁ 1 6 9 9 . ▁▁ ▁He ▁wrote ▁a ▁detailed ▁description ▁of ▁the ▁instrument ▁for ▁Ed mond ▁Hal ley , ▁which ▁was ▁published ▁in ▁ 1 7 4 2 . ▁Due ▁to ▁this ▁time ▁lap se , ▁credit ▁for ▁the ▁in vention ▁has ▁often ▁been ▁given ▁instead ▁to ▁John ▁Had ley ▁and ▁Thomas ▁God f rey . ▁The ▁oct ant ▁eventually ▁replaced ▁earlier ▁cross - st aff s ▁and ▁Davis ▁quadr ants , ▁ ▁and ▁had ▁the ▁immediate ▁effect ▁of ▁making ▁latitude ▁calculations ▁much ▁more ▁accurate . ▁ ▁A ▁highly ▁important ▁break through ▁for ▁the ▁accurate ▁determ ination ▁of ▁longitude ▁came ▁with ▁the ▁in vention ▁of ▁the ▁marine ▁chron ometer . ▁The ▁ 1 7 1 4 ▁longitude ▁prize ▁offer ▁for ▁a ▁method ▁of ▁determ ining ▁longitude ▁at ▁sea , ▁was ▁won ▁by ▁John ▁Harrison , ▁a ▁York shire ▁car p enter . ▁He ▁submitted ▁a ▁project ▁in ▁ 1 7 3 0 , ▁and ▁in ▁ 1 7 3 5 ▁completed ▁a ▁clock ▁based ▁on ▁a ▁pair ▁of ▁counter - osc ill ating ▁weight ed ▁be ams ▁connected ▁by ▁spr ings ▁whose ▁motion ▁was ▁not ▁influenced ▁by