Note 162 — Chapter XIV · NUMBER OF THE MODES OF PROROGATION

On this passage, there has been founded (to use Whalley’s words) “what we call Mundane Parallels, or parallels in the world. And, as zodiacal parallels are equal distances from the tropical or equinoctial circles, so mundane parallels are a like equal distance from the horizontal or meridianal points or circles. And as zodiacal parallels are measured by the zodiacal circle, so those mundane parallels are measured by the diurnal or nocturnal arcs: and just so long as the Sun or any other planet is, in proceeding from the cusp of the twelfth House to the cusp of the tenth, the same Sun or other planet will be in proceeding from the cusp of the tenth to the cusp of the eighth House. And the distance between Sun-rising and setting, is the diurnal arc which the meridian cuts in two equal parts. In directions, these mundane parallels have a twofold consideration: first, simple; secondly, according to the rapt motion of the earth, or the primum mobile: all which have been largely explained by the learned Monk, Placidus,” &c. That Author has certainly stated, in one of his Theses, that “those seats, or parts of the circle, are to be received, in which the stars, having a different declination, effect equal temporal hours” (p. 22, Cooper’s Translation), and he has fully exemplified this principle in other parts of his “Primum Mobile”; but Ptolemy here speaks only of one of the semicircles between the horizon and meridian, without reference to any other semicircle, corresponding in distance from the horizon and mid-heaven; and all that he has said on the subject amounts only to this, that the prorogation is completed when the succeeding place arrives at the same semicircle on which the preceding place had been posited.