Directions are of two kinds, _primary_ and _secondary_, and are based upon arithmetical calculations of the time of the events caused by the aspects of the significators (that is, of the Sun or the Moon), with the places of the planets. They are founded upon the familiarities of the stars amongst each other in the zodiac (_after the nativity_), and show, by calculations, the distance of the place of a significator at the moment of the nativity from the place it must reach before it can join the aspect, which distance is called _the Arc of Direction_. Some astrologers consider what are called "_Mundane Directions_," which are distances in the world measured by the semi-arc, and are wholly independent of the zodiac. These were invented by Placidus, but as Ptolemy does not treat of them they will not be considered here. It must always be remembered that--in directions--the place of a planet, at the time of the nativity, is called the planet itself, although it may not be there when the significator arrives; thus, if we wish to direct the Sun to the conjunction of Jupiter, we must do so to the position which that planet occupied _at the moment_ of the nativity. When the Arc of Direction is found the Sun's right ascension must be added to it, and the Sun will be the right ascension (without latitude) of that place in the zodiac at which, when the Sun arrives, the direction will be completed. For every day of the Sun's approach to this point a year must be added, and thus the time when the event is likely to happen is pointed out: these primary directions, however, cannot be depended upon to produce an event of great importance unless the secondary directions agree; but where the nativity is weak the primary direction alone is powerful enough to kill (especially if it should be opposed to the Hyleg), and misfortune will always happen if the positions of the planets, at the moment of birth, are unfortunate, _without_ the coincidence of any secondary direction.