MERIDIAN SUN

The sun in the South is represented in Freemasonry by the Junior Warden, for this reason: when the sun has arrived at the zenith, at which time he is in the South, the splendor of his beams entitles him to the appellation which he receives in the instructions as "the beauty and glory of the day." Hence, as the Pillar of Beauty which supports the Lodge is referred to the Junior Wardens that officer is said to represent "the sun in the South at High Twelve," at which hour the Craft are called by him to refreshment, and therefore is he also placed in the South that he may the better observe the time and mark the progress of the shadow over the dialplate as it crosses the meridian line.

- Source: Mackey's Encyclopedia of Freemasonry