Mathematical dissertaions on a variety of physical and analytical subjects. [electronic resource] : Containing, among other particulars, a demonstration of the true figure which the Earth, or any planet must acquire from its rotation about an axis. A general investigation of the attraction at the surfaces of bodies nearly spherical. A determination of the meridional parts, and the lengths of the several degrees of the meridian, accoding to the true figure of the Earth. An investigtion of the height of the tides in the ocean. A new theory of astronomical-refractions, with exact tables deduced therefrom. A new and very exact method for approximating the roots of equations in numbers; that quintuples the number of places at each operation. Several new methods for the summation of series. Some new and very useful improvements in the inverse method of fluxions. The whole in a general and perspicuous manner. By Thomas Simpson.