Why "integralis" over "summatorius"? It is written that Johann Bernoulli suggested to Leibniz that he (Leibniz) change the name of his calculus from "calculus summatorius" to "calculus integralis", but I cannot find their correspondence wherein Bernoulli explains why he thinks "integralis" is preferable to "summatorius." Can someone enlighten me? Thank you. 

If you wanted the correspondence. Maybe, this would be sure, the initial quotation states the exact point. As for the reason, some say that it was to rival Newton on proving that he had invented calculus first. The Bernoulli's too were involved in the controversy.This page explains the controversy.
