▁not ▁match ▁his ▁amb itions , ▁in ▁ 1 9 1 2 ▁he ▁went ▁to ▁Kar ls ru he , ▁where ▁he ▁worked ▁as ▁an ▁assistant ▁of ▁professor ▁Otto ▁Le h mann ▁at ▁the ▁Fac ulty ▁of ▁Physics ▁at ▁the ▁local ▁Poly techn ic ▁for ▁four ▁months . ▁So on ▁after ▁that , ▁he ▁moved ▁to ▁Zur ich , ▁where ▁on ▁ 2 6 ▁May ▁ 1 9 1 3 ▁he ▁received ▁a ▁hab il itation ▁at ▁the ▁E TH ▁( review ers : ▁Albert ▁Ein stein ▁and ▁Pierre ▁We iss ) ▁and ▁in ▁the ▁next ▁year ▁– ▁at ▁the ▁k ant onal ▁University ▁( review ers ▁Max ▁von ▁La ue ▁and ▁Alfred ▁Kle iner ). ▁Until ▁the ▁end ▁of ▁his ▁stay ▁in ▁Zur ich ▁he ▁lect ured ▁at ▁both ▁of ▁these ▁univers ities . ▁He ▁also ▁worked ▁for ▁Carl ▁Ze iss ▁and ▁Brown ▁B over i , ▁but ▁he ▁consist ently ▁rejected ▁any ▁propos itions ▁of ▁permanent ▁and ▁well - pa id ▁jobs ▁in ▁the ▁industry . ▁In ▁ 1 9 1 5 ▁his ▁son , ▁Kar ol ▁Wolf ke , ▁was ▁born ▁and ▁in ▁ 1 9 1 8 , ▁the ▁daughter , ▁Luc yna ▁was ▁born . ▁ ▁After ▁the ▁rest oration ▁of ▁Poland ' s ▁independence ▁in ▁ 1 9 1 8 , ▁Wolf ke ▁obtained ▁a ▁Polish ▁pass port . ▁In ▁ 1 9 2 0 ▁he ▁got ▁a ▁proposal ▁to ▁take ▁the ▁position ▁of ▁professor ▁at ▁the ▁University ▁of ▁Wars aw ▁and ▁accepted ▁the ▁nom ination ,