Egyptian Method

greek: περίπατος (peripatos) — circumambulation; the parent technique of primary directions · latin: mensura Ptolemaica — Ptolemy's measure (distinguished by Naibod as the value he refined)

Definition

The Egyptian Method (also Ptolemy's measure) is the simplest time-scale convention for primary directions: one degree of arc between significator and promittor is equated to one year of life. The arc of direction in degrees is read directly as the year at which the directed contact perfects. This 1°-per-year convention is the baseline against which later refinements — most notably Naibod's measure (0°59′08″, the Sun's mean daily motion in longitude) and Placidean semi-arc methods — were proposed to improve accuracy.

In Tradition

Traditional Western practice treats the 1°-per-year measure as Ptolemy's original time-scale convention for the primary-direction technique. Holden frames Naibod's 0°59′08″ rate as 'a refinement of Ptolemy's value of exactly 1 degree per year,' positioning Naibod against the Ptolemaic baseline rather than as its replacement. Practitioners read the convention as the simplest of several competing rates by which arc-of-direction is mapped to time-of-life.

In Practice

After computing the arc of direction in degrees between a significator (typically the hyleg or one of the angles) and a promittor (a planet or aspect-point reached by the diurnal cycle), the practitioner divides the arc by the chosen rate to obtain the year at which the contact perfects. Under the 1°-per-year Egyptian convention the arc is read directly: an arc of 35° matures at age 35. Under Naibod's refinement the same arc is divided by 0°59′08″, yielding a slightly later year. Modern practice typically prefers Naibod's or Placidean-semi-arc rates for length-of-life and major-event timing, retaining the Egyptian rate chiefly for didactic introduction or as a quick first approximation.

Historical Origin

The 1°-per-year convention is preserved in Ptolemy's *Tetrabiblos* III as the original Hellenistic measure for circumambulations (the ancestor of primary directions). Crane traces the technique through the Hellenistic compendia and Ptolemy's reform at III.11. Naibod's *Enarratio elementorum astrologiae* (Cologne 1560) introduces the 0°59′08″ refinement, which Holden documents as displacing the Ptolemaic baseline in many later Western traditions.

Etymology

Origin: English. Meaning: 'Egyptian' attaches by attribution to the Ptolemaic-Egyptian Alexandrian school in which the rate was canonized; the technique itself is Hellenistic in origin and named for its school of transmission rather than for an independent Egyptian astronomical doctrine.

Definition

In Tradition

In Practice

Historical Origin

Etymology

Further Reading