^{page 308 note *} The First person who obtained any direct information of the elliptical orbit of the Planet was the celebrated Abbé Boscovich, who, in October or November 1781, deduced elements of its orbit from the observations of Mr Mechain. His method is exceedingly ingenious, and remarkable for that Simplicity and geometrical elegance which characterise all his performances. It did not come to my knowledge till the beginning of this present year 1787, when I found it in the Collection which he published at Bassano, in 1785, in five volumes. He makes use of the same physical principles which I employed in January 1783, to determine the orbit by the two oppositions which had then been observed, combined with another observation, made at the distance of a sydereal year from one of the oppositions. This method I communicated to Dr Maskelyne in 1783.

^{page 314 note *} For the angular velocity of a body in an ellipse, is to that of a body in a circle, at the same distance, in the subduplicate ratio of the half parameter to the distance.