Note 45 — Chapter V · ToC

The method employed is as follows: Let t0 be the computed time (9h. 51m. 6s.) at the focus, x seconds the error in this estimate, t the reported time at a given place, D its distance from the focus in miles, and y the number of seconds required to travel one mile; then, assuming that y does not vary with the distance, we have x + Dy = t + t0. An equation of this form is obtained from each observation, and the method of least squares is then applied to determine the most probable values of x and y.