Traditional Russian units of measurement were standardized and used in Imperial Russia and after the Russian Revolution, but it was abandoned after 21 July 1925, when the Soviet Union adopted the metric system, per the order of the Council of People's Commissars. The Tatar system is very similar to the Russian one, but some names are different. The Polish system is also very close to the Russian. The system existed since ancient Rus', but under Peter the Great, the Russian units were redefined relative to the English system. Until Peter the Great the system also used Cyrillic numerals, and only in the 18th century did Peter the Great replace it with the Hindu–Arabic numeral system. Length The basic unit was the Russian ell, called the arshin, which came into use in the 16th century. It was standardized by Peter the Great in the 18th century to measure exactly twenty-eight English inches (). Thus, 80 vershoks = 20 piads = 5 arshins = 140 English inches (). A pyad (, "palm", "five") or chetvert (, "quarter") is a hand span, the distance between ends of the spread thumb and index finger. Alternative units: Swung sazhen (, , distance between tips of arms stretched sidewards) = 1.76 m Skewed, or oblique sazhen (, , distance between tip of a raised arm and a tip of an opposite leg slightly put away) = 2.48 m / 2.4892 m to be exact, since 1 Kosaya Sazhen is equal to 3.5 Arshins which is equal to 98 inches Double versta or border versta, (, ), used to measure land plots and distances between settlements = 2 verstas (comes from an older standard for versta) Area Desyatina (, "a tenth" or "ten"), approximately one hectare Treasury/official desyatina (, ) = 10,925.4 m2 = 117,600 sq ft = 2.7 acres = 2,400 square sazhen Proprietor's (, ) = 14,567.2 m2 = 156,800 sq ft = 3,200 square sazhen 3 proprietor's desyatinas = 4 official desyatinas Sokha (, "big plow") Volume As in many ancient systems of measurement the Russian distinguishes between dry and liquid measurements of capacity. Note that the chetvert appears in both lists with vastly differing values. Dry measures Liquid measures Weight/mass Two systems of weight were in use, an ordinary one in common use, and an apothecaries' system. Ordinary system The pood was first mentioned in a number of documents of the twelfth century.