1 in Same Measures: Harappa to Taj
A researcher analysing designs of historical buildings and monuments of India has made a profound discovery. He has shown that the unit of length used by the builders through the ages surprisingly remained the same for over 3900 years. This reveals a new dimension in metrology — the science of measurement — in the Indian subcontinent.
From the Harappan settlements of 2000 B. C. and the Delhi Iron Pillar of Gupta period (320–600 AD) to the 17th century Taj Mahal, the unit 'angulam ' had remained the standard of measurement in engineering plans, says Ramamurthy Balasubramaniam from the Indian Institute of Technology (IIT) in Kanpur.
Angulam and its multiples vitasti (12 angulams) and dhanus (108 angulams) find mention in the Indian treatise Arthasastra by Kautilya who codified the metrology that was prevalent around 300 B.C. But the exact value of angulam was derived only in 2008 by Michel Danino, the French author who made India his home.
Danino who studied the Dolavira settlement — the largest Harappan civilization site in India — found1 that the dimensions used were exact multiples of 1.904 metre, a unit that he assumed to be the dhanus mentioned in Arthasastra. Further, taking dhanus to be 108 angulams, Danino derived the value of angulam to be 1.763 cm.
Balasubramaniam, a professor of materials and metallurgical engineering, says he got interested in metrology after Danino 's derivation of the value of angulam and his own observation2 that a terracotta scale of Harappan civilisation from Kalibangan, that was given to him for analysis, indicated markings of 1.75 cm.
"Seeing 1.75 cm markings on the Harappan scale and Danino 's derived value of 1.763 cm for angulam no doubt excited me," Balasubramaniam told Nature India. "That prompted me to carry out dimensional analysis of some of India 's historical structures to see if their builders used a standardised unit of measurement," he said.
Balasubramaniam who studied the 1600 year old Delhi Iron Pillar3
From the Harappan settlements of 2000 B. C. and the Delhi Iron Pillar of Gupta period (320–600 AD) to the 17th century Taj Mahal, the unit 'angulam ' had remained the standard of measurement in engineering plans, says Ramamurthy Balasubramaniam from the Indian Institute of Technology (IIT) in Kanpur.
Angulam and its multiples vitasti (12 angulams) and dhanus (108 angulams) find mention in the Indian treatise Arthasastra by Kautilya who codified the metrology that was prevalent around 300 B.C. But the exact value of angulam was derived only in 2008 by Michel Danino, the French author who made India his home.
Danino who studied the Dolavira settlement — the largest Harappan civilization site in India — found1 that the dimensions used were exact multiples of 1.904 metre, a unit that he assumed to be the dhanus mentioned in Arthasastra. Further, taking dhanus to be 108 angulams, Danino derived the value of angulam to be 1.763 cm.
Balasubramaniam, a professor of materials and metallurgical engineering, says he got interested in metrology after Danino 's derivation of the value of angulam and his own observation2 that a terracotta scale of Harappan civilisation from Kalibangan, that was given to him for analysis, indicated markings of 1.75 cm.
"Seeing 1.75 cm markings on the Harappan scale and Danino 's derived value of 1.763 cm for angulam no doubt excited me," Balasubramaniam told Nature India. "That prompted me to carry out dimensional analysis of some of India 's historical structures to see if their builders used a standardised unit of measurement," he said.
Balasubramaniam who studied the 1600 year old Delhi Iron Pillar3
References: 1. Danino, M. New insights into Harappan town-planning, proportions, and units, with special reference to Dholavira. Man Environ. 33, 66-79 (2008) 2. Balasubramaniam, R. et al. Analysis of terracotta scale of Harappan civilization from Kalibangan. Curr. Sci. 95, 588-589 (2008) 3. Balasubramaniam, R. On the mathematical significance of the dimensions of the Delhi Iron Pillar. Curr. Sci. 95, 766-770 (2008) 4. Balasubramaniam, R. New insights on the modular planning of the Taj Mahal. Curr. Sci. 97, 42-49 (2009)