Footnote 41
Part II, §15.  This is best done by help of the back of the instrument, fig. 1.  Thus May 13 (old style), which lies 30° to the W. of the S. line, is nearly of the same length as July 13, which lies 30° to the E.  Secondly, the day of April 2 (old style), 20° above the W. line, is nearly of the same length as the night of Oct. 2, 20° below the E. line, in the opposite point of the circle.  This is but an approximation, as the divisions on the instrument are rather minute.