Merkhet

MER-ket

Definition

A merkhet is an ancient Egyptian sighting tool — a horizontal bar with a plumb-bob (a weighted line) hanging from one end. Used together with the bay, a notched palm-rib sighting rod, it let an observer find the meridian (the imaginary north-south line overhead) by watching stars cross it, and so fix true cardinal directions. The Egyptian word mrḫt means "instrument of knowing."

In Tradition

Egyptologists treat the merkhet as one of the two main sighting devices for finding the meridian, always paired with the bay. Egyptian astronomer-priests used it both to align temples precisely when laying their foundations and, night after night, to time the decans — stars whose crossings of the meridian set the hours of the night recorded on the diagonal star clocks.

In Practice

Two merkhets were usually worked together: one held upright so its plumb-line gave a true vertical, the other held by an observer who sighted along the bay to catch a star as it crossed overhead. Lining up the plumb-bob, the bay's slit, and the target star fixed the meridian for that moment. Surviving examples confirm this: instruments belonging to the priest Hor (Berlin Museum 14084, the notched palm-rib bay, and 14085, a rule shaped like a shadow clock; about the 6th century BCE, transcribed by Borchardt in 1899). The temple-foundation ceremony known as the Stretching of the Cord (pedj-shes) used the same kind of sighting on Meskhetyu — the Bull's Foreleg, our Big Dipper — to set a temple's axis, with the goddess Seshat presiding. Belmonte and Magli (2009a) have even suggested the eight-rayed Seshat sign was itself a three-dimensional surveying instrument, much like the Roman groma.

Historical Origin

The merkhet appears in inscriptions from the Old Kingdom onward, and a few instruments survive — the Hor instruments in the Berlin Museum (14085 and 14084, about the 6th century BCE) and the statue of the astronomer Harkhebi (3rd century BCE, found at Tell Faraoun in 1906 by Kamal, republished by Daressy in 1916). Modern study: Clagett, Ancient Egyptian Science Vol II (1995), Documents III.18 and III.16; Belmonte and Lull, In Search of Cosmic Order (2009); Neugebauer and Parker, Egyptian Astronomical Texts.

Definition

In Tradition

In Practice

Historical Origin

Further Reading