Invented by the geodesist (Earth surveyor) Ulysses Grant Morrow who was a member of the Koreshan Unity headed by Cyrus Teed. As already stated, both Teed and Morrow wrote the book Cellular Cosmogony, claiming that we live inside a concave Earth. To verify these claims Morrow made a simple invention called the rectilineator.
This was a series of 12-foot long, 8-inch wide, 12-year seasoned mahogany supports held up by two vertical posts (which Teed calls “standards”) with brass castings attached which could be adjusted for height by turning set screws on the front sides of each.
Through flanges on the facings, ingenious screws were placed for securing the adjustments when made… each section was supported by two strongly built platformed standards, with adjustable castings to receive the horizontal sections between the body of the castings and adjustable cleats with clamps and screws. The sections rest in the castings edgewise…
A Line Has Been Drawn! The Rectilineator Documentary
Enjoy Steven's little work of reconstructing the 1897 Rectilineator Experiment in 3D, which conclusively proved the curvature to the earth curves up instead of down, or not at all.
Konkave Erde - Geradstreckenverleger-Experiment von Cyrus Teed
The cellular cosmogony, or, The earth, a concave sphere:
Concave Earth/Glass Sky Truth Facebook Group:
Andreas Taraldsen (original score)