Daily Motion

greek: προσθέσει ἀριθμῶν (prosthesei arithmōn, 'adding to numbers' = swift) · latin: motus diurnus

Definition

Daily motion is the arc a planet traverses through the zodiac in a 24-hour period, measured in degrees and minutes. Each planet has a characteristic mean daily motion (the Moon roughly 13°, the Sun roughly 1°, Mercury and Venus near 1° on average, the outer planets progressively less), and any given day's actual motion may be faster or slower than that mean depending on the planet's position on its orbit and on its retrograde-direct status.

In Tradition

Across Hellenistic and Arabic-Persian tradition daily motion is read as one of the basic accidental conditions of a planet. A planet moving faster than its mean daily motion is judged swift and strengthened; a planet moving slower is judged slow and weakened; the maximum slow-down occurs around a station, when motion reverses between direct and retrograde phases.

In Practice

Astrologers compare a planet's actual daily motion on the chart's date to the planet's mean daily motion. The Hellenistic technical term for faster-than-mean motion is 'adding to numbers' (Greek prosthesei arithmōn) — Holden footnotes this in Rhetorius's eighth-house delineations, glossing it simply as 'swift,' the condition the Arabian astrologers later codified as 'increasing in course.' In delineation, swift motion intensifies favourable significations and accelerates timing, while slow motion delays and weakens them. The reading is integrated with retrograde-direct status: a planet retrograde and slow is doubly debilitated; a planet direct and swift is doubly strengthened. In horary judgment a swift significator brings the matter to perfection quickly; a slow significator portends delay.

Historical Origin

The Hellenistic prosthesei arithmōn / 'adding to numbers' doctrine is preserved by Rhetorius and footnoted as 'swift' by Holden in *A History of Horoscopic Astrology* (2006). The accidental-dignity register including swift-vs-slow motion is codified in Lilly's *Christian Astrology* (1647) within the standard checklist of planetary condition; Lehman's *Essential Dignities* preserves the doctrine in modern traditional practice.

Etymology

Origin: Latin. Meaning: From motus diurnus, 'daily motion' — the arc traversed in one diurnal revolution..

Further Reading