<P> Standard weights and measures were developed by the Indus Valley Civilisation . The centralised weight and measure system served the commercial interest of Indus merchants as smaller weight measures were used to measure luxury goods while larger weights were employed for buying bulkier items, such as food grains etc . Weights existed in multiples of a standard weight and in categories . Technical standardisation enabled gauging devices to be effectively used in angular measurement and measurement for construction . Uniform units of length were used in the planning of towns such as Lothal, Surkotada, Kalibangan, Dolavira, Harappa, and Mohenjo - daro . The weights and measures of the Indus civilisation also reached Persia and Central Asia, where they were further modified . Shigeo Iwata describes the excavated weights unearthed from the Indus civilisation: </P> <P> A total of 558 weights were excavated from Mohenjodaro, Harappa, and Chanhu - daro, not including defective weights . They did not find statistically significant differences between weights that were excavated from five different layers, each measuring about 1.5 m in depth . This was evidence that strong control existed for at least a 500 - year period . The 13.7 - g weight seems to be one of the units used in the Indus valley . The notation was based on the binary and decimal systems . 83% of the weights which were excavated from the above three cities were cubic, and 68% were made of chert . </P> <P> Rulers made from Ivory were in use by the Indus Valley Civilisation prior to 1500 BCE . Excavations at Lothal (2400 BCE) have yielded one such ruler calibrated to about ⁄ inch (1.6 mm). Ian Whitelaw (2007)--on the subject of a ruler excavated from the Mohenjo - daro site--writes that:' the Mohenjo - Daro ruler is divided into units corresponding to 1.32 inches (33.5 mm) and these are marked out in decimal subdivisions with amazing accuracy--to within 0.005 of an inch . Ancient bricks found throughout the region have dimensions that correspond to these units .' The Indus civilisation constructed pan balances made of copper, bronze, and ceramics . One excavated pan balance from Mohenjo - daro (2600--1900 BCE) was constructed using a cord - pivot type fulcrum, a bronze beam, and two pans . A number of excavated surveying instruments and measuring rods have yielded evidence of early cartographic activity . </P> <P> Weights and measures are mentioned throughout the religious and secular works of the Vedic period in India . Some sources that mention various units of measurement are Satapatha Brahmana, Apastamba Sutra, and the Eight Chapters of the grammarian Pāṇini . Indian astronomers kept a pañcānga for calculations of tithi (lunar day), vāra (weekday), naksatra (asterism), and karan (half lunar day) for social and religious events . Klostermaier (2003) states that: "Indian astronomers calculated the duration of one kalpa (a cycle of the universe during which all the heavenly bodies return to their original positions) to be 432, 00, 00,000 years ." </P>

Who introduced the system of land measurement in india