Noun
One who reckons or computes; also, a book of calculations, tables, etc., to assist in reckoning.
Source: Webster's dictionaryThe Sand Reckoner or Psammites is the only surviving work in which Archimedes discusses his views on astronomy. citation * The Method of Mechanical Theorems :This treatise was thought lost until the discovery of the Archimedes Palimpsest in 1906. Source: Internet
The Sand Reckoner is a work by Archimedes in which he sets out to determine an upper bound for the number of grains of sand that fit into the universe. Source: Internet
Though the original text has been lost, a reference in Archimedes ' book The Sand Reckoner describes Aristarchus's heliocentric model. Source: Internet