▁wrote ▁a ▁number ▁of ▁articles ▁and ▁books ▁on ▁maps ▁of ▁expl or ers ▁including ▁Captain ▁James ▁Cook ' s ▁maps ▁of ▁New found land , ▁including ▁The ▁Marine ▁Sur ve ys ▁of ▁Captain ▁James ▁Cook ▁in ▁North ▁America ▁ 1 7 5 8 - 1 7 6 8 , ▁and ▁the ▁English ▁translation ▁and ▁comment ary ▁to ▁the ▁fac sim ile ▁edition ▁of ▁Antonio ▁P ig af etta ' s ▁narr ative ▁account ▁of ▁the ▁first ▁circ umn avigation ▁by ▁Mag ellan ▁( 1 5 1 9 - 1 5 2 2 ), ▁Y ale ▁University ▁Press , ▁ 1 9 6 9 . ▁ ▁Professional ▁activities ▁Sk el ton ▁served ▁as ▁the ▁Honor ary ▁Secretary ▁of ▁the ▁H ak lu yt ▁Society ▁from ▁ 1 9 4 6 ▁to ▁ 1 9 6 6 . ▁He ▁was ▁the ▁General ▁Editor ▁of ▁Im ago ▁M und i , ▁the ▁major ▁journal ▁in ▁the ▁field ▁of ▁the ▁history ▁of ▁cart ography , ▁from ▁ 1 9 5 7 ▁to ▁ 1 9 7 0 . ▁This ▁was ▁a ▁collaboration ▁with ▁R . ▁V . ▁To ole y . ▁He ▁was ▁Chair ▁of ▁the ▁Working ▁Group ▁on ▁Early ▁Maps ▁of ▁the ▁International ▁Ge ographical ▁Union ▁from ▁ 1 9 6 1 . ▁He ▁was ▁also ▁a ▁member ▁of ▁the ▁Ac adémie ▁Intern ationale ▁d ' H istoire ▁des ▁Sciences ▁and ▁of ▁various ▁other ▁soci eties ▁concerned ▁with ▁history , ▁ge ography , ▁arch ae ology , ▁bibli ography ▁and ▁arch ives . ▁During ▁a ▁s