Chapter VI: Section 5

THE DIAMETER OF THE SUN’S PATH IS CONSTANTLY CHANGING--DIMINISHING FROM DECEMBER 21ST TO JUNE 15TH, AND ENLARGING FROM JUNE TO DECEMBER.

This is a matter of absolute certainty, proved by what is called, in technical language, the northern and southern declination, which is simply saying that the Sun’s path is nearest the north pole in summer, and farthest away from it in winter. This difference in position gives rise to the difference of altitude, as observed at various periods of the year, and which is shewn in the following table, given in “The Illustrated London Almanack,” for 1848, by Mr. Glaisher, of the Royal Observatory, Greenwich.

“Sun’s altitude at the time of Southing, or being on the meridian:--

Sun’s Time of Southing.
altitude. M. S. (Common clock, or
London mean time.)
June 15 62° 0 4 before noon.
„ 30 61²⁄₃° 3 18 afternoon.
July 15 59²⁄₃° 5 38 „
„ 31 56¹⁄₂° 6 4 „
Aug. 15 52¹⁄₂° 0 11 „
„ 31 47° 0 5 „
Sep. 15 38²⁄₃° 4 58 before noon.
„ 30 35¹⁄₂° 10 6 „
Oct. 31 24° 16 14 „
Nov. 30 17° 10 58 „
Dec. 21 12° 0 27 „
„ 31 15° 3 29 afternoon.
Jan. 1 15¹⁄₂° 3 36 „
„ 15 17° 9 33 „
„ 31 21° 13 41 „
Feb. 15 25° 14 28 „
„ 29 30¹⁄₂° 12 43 „
March 15 {On the Equator} 36° 9 2 „
{ at 6 a.m. } 38¹⁄₂° 0 0 „
„ 21 42¹⁄₂° 4 10 before noon.
April 15 48° 0 8 „
„ 30 53° 2 58 „
May 15 57° 3 54 „
„ 31 60° 2 37 „

In the following diagram (Fig. 27) A A A represent the Sun’s daily path on December 21st, and B B B the same on June 15th. N the North Pole, S the Sun, E Great Britain. The figures 1 2 3 the Arctic Circle, and 4 5 6 the extent of sunlight. The arrows show the direction of the Sun’s motion.