In "Method of Fluxions" (written 1671, published 1736), Sir Isaac Newton examined the transformations between polar coordinates, which he referred to as the "Seventh Manner; For Spirals", and nine other coordinate systems. In the journal "Acta Eruditorum" (1691), Jacob Bernoulli used a system with a point on a line, called the "pole" and "polar axis" respectively. Coordinates were specified by the distance from the pole and the angle from the "polar axis". Bernoulli's work extended to finding the radius of curvature of curves expressed in these coordinates.