Benchmarks are cast-iron plates installed at preset altitudes above sea level inside the walls of edifices, concrete monoliths or steep cliffs and displaying specific above-sea-level altitudes and dates. The Russian term "nivelirovaniye", or "leveling," derives from the French word "niveau" ("level"), denoting absolute altitudes of various terrestrial-surface points above sea level, as well as their relative altitudes.
The establishment of leveling networks, which feature a multitude of benchmarks, is an essential part of surveying operations, as well as earthquake forecast programs. Regular measurement of relative benchmark altitudes makes it possible for specialists to assess seismic danger of a specific locality.
In 1877, professors and students of the Constantine Abutment College chose a vantage point for calculating local altitudes from the Moskva River's level near St. Daniel's Chapel. The relevant benchmark was placed inside the chapel wall. (The Moscow State Surveying & Mapping University and the State Land Management University now train specialists in lieu of the now defunct Abutment College - Ed.)
The history of science knows of no other case of using churches or monasteries as a reference point for calculating specific coordinates, spokespeople for the Patriarch's Spiritual Center pointed out. The unique leveling network consisted of several hundred metal benchmarks featuring serial numbers, the date of laying, and high-precision altitude readings (with the degree of accuracy up to 0.01 sazhens, or two centimeters). Only a few of those benchmarks have come downto us.
The original benchmark was destroyed along with the Chapel of St. Daniel's Monastery in 1930.
The chapel itself was restored in 1998. In August 2004, an exact replica of the first benchmark was installed inside the chapel wall at its original height (about one meter above ground level). The benchmark is a pig-iron triangle measuring 23 by 13 centimeters. It provides the following data: year, 1877; serial number, 2210; height above sea level, 7.77 sazhens (approximately 16.55 meters).
