▁long - distance ▁elect rical ▁transm issions . ▁While ▁at ▁AT & T , ▁she ▁studied ▁elect rical ▁engineering ▁at ▁Columbia ▁University ▁by ▁night . ▁ ▁In ▁ 1 9 1 8 , ▁Clar ke ▁en rolled ▁at ▁the ▁Massachusetts ▁Institute ▁of ▁Technology , ▁and ▁the ▁following ▁year ▁she ▁became ▁the ▁first ▁woman ▁to ▁ear n ▁an ▁M . S . ▁in ▁elect rical ▁engineering ▁from ▁M IT . ▁Clar ke ' s ▁th esis ▁at ▁M IT ▁was ▁super vised ▁by ▁A . E . K enn elly ▁and ▁was ▁titled ▁" Behavior ▁of ▁a ▁lum py ▁artificial ▁transmission ▁line ▁as ▁the ▁frequency ▁is ▁in def initely ▁increased ." ▁ ▁Professional ▁career ▁Unable ▁to ▁find ▁work ▁as ▁an ▁engineer , ▁Clar ke ▁went ▁to ▁work ▁for ▁General ▁Electric ▁as ▁a ▁super visor ▁of ▁computers ▁in ▁the ▁Tur bine ▁Engineering ▁Department . ▁During ▁this ▁time , ▁she ▁invent ed ▁the ▁Clar ke ▁calcul ator , ▁a ▁simple ▁graph ical ▁device ▁that ▁solved ▁equations ▁involving ▁electric ▁current , ▁voltage ▁and ▁imped ance ▁in ▁power ▁transmission ▁lines . ▁The ▁device ▁could ▁solve ▁line ▁equations ▁involving ▁hyper bol ic ▁functions ▁ten ▁times ▁faster ▁than ▁previous ▁methods . ▁She ▁file d ▁a ▁pat ent ▁for ▁the ▁calcul ator ▁in ▁ 1 9 2 1 ▁and ▁it ▁was ▁granted ▁in ▁ 1 9 2 5 . ▁▁▁▁ ▁In ▁ 1 9 2 1 , ▁Clar ke ▁took ▁a ▁leave ▁of ▁absence ▁from ▁G E ▁to ▁teach ▁physics ▁at ▁the ▁Constantin ople ▁Women ' s ▁College ▁in ▁Turkey .