ical ▁reflection , ▁magnetic ▁rot ational ▁forces , ▁or ▁inter ference ▁fr ing es . ▁He ▁contributed ▁extensive ▁notes ▁to ▁J C ▁Max well ’ s ▁treat ise ▁on ▁elect romagnet ism , ▁facil it ating ▁its ▁reading ▁in ▁France . ▁▁ ▁Pot ier ▁was ▁a ▁member ▁of ▁many ▁comm itte es ▁at ▁the ▁famous ▁ 1 8 8 1 ▁Universal ▁Ex position ▁in ▁Paris , ▁including ▁the ▁one ▁that ▁set ▁the ▁standards ▁for ▁units ▁in ▁electric ity . ▁The ▁French ▁Physics ▁Society ▁appointed ▁Pot ier ▁as ▁president ▁in ▁ 1 8 8 4 ; ▁the ▁International ▁Elect r icians ▁Society ▁did ▁the ▁same ▁in ▁ 1 8 9 5 . ▁In ▁ 1 8 9 1 ▁he ▁was ▁accepted ▁into ▁the ▁French ▁Academy ▁of ▁Science . ▁ ▁Speed ▁of ▁light ▁Following ▁Thomas ▁Young ’ s ▁ideas , ▁light ▁was ▁regarded ▁in ▁the ▁ 1 9 th ▁century ▁to ▁move ▁as ▁v ibr ations ▁( und ulations ) ▁in ▁a ▁subst ance ▁called ▁the ▁L umin ifer ous ▁a ether , ▁contrary ▁to ▁Newton ’ s ▁ideas ▁that ▁light ▁itself ▁was ▁made ▁of ▁substant ive ▁cor pus cles . ▁Ex pl oring ▁the ▁nature ▁of ▁this ▁a ether , ▁Albert ▁Michel son ▁published ▁in ▁ 1 8 8 1 ▁his ▁labor atory ▁experiments ▁where ▁he ▁had ▁light ▁travel ▁in ▁the ▁direction ▁of ▁the ▁earth ’ s ▁motion ▁and ▁per pend icular ▁to ▁it . ▁Thus ▁measured ▁on ▁the ▁moving ▁earth , ▁he ▁found ▁no ▁difference ▁in ▁the ▁speed ▁of ▁light ▁travel ing ▁with