^{page 100 note *} November, December, and January, have been taken as the three winter months.

^{page 103 note *} The line should have been drawn through January 1844 and January 1845, but that there is an irregularity in the progress of the horizontal force from December 1844 to January 1845, compared with the previous years. I have, however, also reduced the means to the line passing through January 1844 and January 1845, and find the ordinate of the morning node slightly increased, but that for the evening node diminished.

^{page 107 note *} Quoted by M. Francoeur; Uranographie, p. 97.

^{page 108 note *} It is evident that the variations of horizontal intensity may be due either to changes of the total intensity, or of its direction; any reasoning, therefore, on these facts must be necessarily incomplete, until we are certain of the actual effect.

^{page 108 note †} I have, since this was written, been favoured by Professor Forbes with a copy of M. Kreill's table for the horizontal force during the moon's hour angle. It indicates a minimum of intensity about two hours before the meridian passage, and maximum peaks at 12^h and 15^h, giving the interpolated period of maximum about 1½ hours after the inferior meridian passage; the latter period agrees completely with my own conclusion, the former differs about three hours from my result.