Pyramid inch

The pyramid inch is a now discredited unit of measure formerly claimed by pyramidologists to have been used in ancient times.

Taylor regarded the "pyramid inch" to be 1/25 of the "sacred cubit", ancient unit based on the forearm length from the tip of the middle finger to the bottom of the elbow, whose existence had earlier been postulated by Isaac Newton.

Taylor and his followers, who included the Astronomer Royal of Scotland Charles Piazzi Smyth (1819–1900),[5] also found numerous apparent coincidences between the measurements of the pyramids and the geometry of the earth and the solar system.

During the 19th and early 20th centuries, this theory played a significant role in the debates over whether Britain and the United States should adopt the metric system.

When Petrie went to Egypt in 1880 to perform new measurements, he found that the pyramid was several feet smaller than previously believed, including the missing capstone.