Orient the principal axis of the monument on the rising or setting of the sun at a solstice, so that the architecture frames it.
Rules · Proportion · Ornament · Site
The obelisk: a ray of the sun in stone
Cut the obelisk from a single block of granite, square in section, tapering to about two-thirds of its base width, capped by a pyramidion, and about ten times as tall as it is wide; set them in pairs before the pylon.
height ≈ 9–11 × base width
The unfinished obelisk still lying in the quarry at Aswan, abandoned when it cracked, would have stood about 42 m high. Surviving obelisks run from a few metres to over 30 m; the Lateran obelisk in Rome, originally at Karnak, is about 32 m. The pyramidion was often sheathed in gilded metal to catch the first light. Rome, Paris, London and New York all took obelisks from Egypt; they became the model for the Washington Monument.
Related rules
Specify the slope of a pyramid face by its seked: the number of palms (and fingers) by which the face runs inward for every cubit of rise. The height follows from half the base divided by the seked, times seven.
seked = 7 × (½ base ⁄ height) palms · angle = arctan(7 ⁄ seked)
The Great Pyramid of Khufu was laid out 440 royal cubits square and 280 cubits high, a seked of exactly 5½ palms and a slope of about 51°50′.
½ × 440 ÷ 280 × 7 = 5½ palms → arctan(7 ⁄ 5.5) ≈ 51.84°
Lay out Egyptian buildings in royal cubits (≈ 52.4 cm) of seven palms of four fingers, so that every dimension and every slope can be stated in whole or simple fractional units.
1 royal cubit = 7 palms = 28 fingers ≈ 0.524 m
Finish every Egyptian wall, gate and shrine with a torus roll and, above it, a deep cavetto (the gorge) curving outward under a flat band.
Model the column on a plant of the Nile (a papyrus stem or bundle, a bundle of lotus, a palm trunk), bound at the neck with five bands, standing on a round base disc and carrying a small square abacus.
Cite this page Chris Paton, “The obelisk: a ray of the sun in stone”, The Textbook of Architecture, https://textbookofarchitecture.com/rule/obelisk. Text, drawings and models licensed under CC BY-NC 4.0.