 Shortly afterward Barrow resigned his chair and was instrumental in securing Newton's election as his successor.Newton was elected Lucasian professor on 29 October 1670.It was his duty as professor to lecture at least once a week in term time on some portion of geometry, arithmetic, astronomy, geography, optics, statics, or some other mathematical subject, and also for two hours in the week to allow an audience to any student who might come to consult with the professor on any difficulties he had encountered.