From Twitter https://twitter.com/: It was #onthisday in 1675, Gottfried Leibniz demonstrated integral calculus for the first time https://en.wikipedia.org/wiki/Gottfried_Wilhelm_Leibniz?utm_source=social_media&utm_medium=hootsuite&utm_campaign=standard https://twitter.com/royalsociety/status/929348554484830209/photo/1 https://chirp.cooleysekula.net/attachment/42670