Geographical mile longitude at the equator is thus exactly 60 geographical miles. It was closely related to the nautical mile, which was originally determined as 1 minute of arc along a great circle of the Earth, but is nowadays defined as exactly 1852 metres. The US National Institute of Standards and Technology (NIST) notes that: "The international nautical mile of 1 852 meters (6 076.115 49...feet) was adopted effective July 1, 1954, for use in the United States. The value formerly used in the United States was 6 080.20 feet = 1 nautical (geographical or sea) mile." (6080.2 feet is 1853.24496 meters.)
Thai units of measurement "wa", "ngan" and "rai" are still used in measurements of land area. The "baht" is still used as a unit of measurement in gold trading. However, one "baht" of 96.5% gold bullion is defined as 15.16 grams rather than the generic standard of 15 grams. The "baht" has also become the name of the currency of Thailand, which was originally fixed to the corresponding mass of silver. Thai units of measurement Thailand adopted the metric system on 17 December 1923. However, old Thai units are still in common use, especially for measurements of land. Before metrication, the traditional system of