Page 64 - Science India August 2022
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Swatantrata ka Amrut Mahotsava
Prof Angus Maddison in his book, The World Economy: A Millennial Perspec- tive, published by the Organisation for Economic Cooperation and Develop- ment (OECD) describes that before 1500 AD , India’s GDP was almost two third of the world economy which reflects the prosperity of the nation at that time. This is a clear indicator that the measurement science and technology of India was very prominent during that period and rather much before that.
That metrology had been well devel- oped in ancient India as evident through various historically significant relics spread across the country and abroad. If we look at the Indus valley civilization (4000 BC – 1500 BC), spread over an area of 1500 km x 1500 km and cov- ering north-west India and present-day Pakistan, had an unbelievably uniform system of weights and measurements. All over the region, the construction bricks had one size with the length, width, and depth being in the ratio 4:2:1; measur- ing tools have been found too. This ratio leads to what is called in the construction technology as the English Bond system. It reveals that they had a proper legal measurement system. Perhaps, India was the first country in the world to officially enforce a system of weights and measure- ments. Indus valley civilization’s town planning, drainage system, water sup- ply, building design etc bear testimony to this.
Now moving forward in time to the Maurya empire (322 BC – 298 BC), the smallest unit of length was considered to be parmanu as given in Kautilya’s Ar- thashastra. Eight (8) parmanu combine together to make 1 rajakhan which is basically 1 dust particle. To make it stan- dard, the rajakhan (dust particle) from the chariot wheel was taken for mea- surement purposes. This rajakhan was the smallest visible physical standard as it could be seen by eye as a suspended dust particle in the air due to the scat- tering of light. Units of length were increased in multiples of 8, starting from parmanu to dhanurmushti. Thus, 1 rajakhan can be defined as 1/85 of dha-
Image Courtesy: Internet
nurmushti, which is roughly 3 microm- eter in size as per current metric system. Thus, interestingly, the size of parma- nu (= 1/8 rajakhan) comes of the order of nearly to the wavelength of visible light. In the modern world, length unit ‘metre’ has been standardised using distance travelled by light in vacuum in 1 second. But, with the fall of the Maurya Empire, the established unit system gradually vanished and was replaced by new mea- surement systems as new empires came into existence and kept changing with time.
Whatever be the era, the units of measurements were always well stan- dardised and enforced, which is indirect- ly evident from various archaeological structures made all across India during different eras. The making of such mag- nificent structures with such precision and durability cannot be possible with- out any proper measurement systems. For example, it is well know that dur- ing the equinox, the Sun is visible from one (1) window at a time out of five (5)
Archaeological remains of the drainage system at Lothal, Gujarat
windows of Shree Padmanabhaswamy Temple in Thiruvananthapuram, Kerala, starting from the top window and mov- ing to the bottom window at an interval of roughly five minutes. This unbeliev- able engineering marvel shows precise construction of the temple windows. It took into account the alignment and accurate position of the Sun with time, windows dimensions, height from the ground and viewer position. These di- mensions, of angles and timings, had to be measured with high precision and ac- curacy to make such structures possible. Similarly, the strong evidence of weight and measurement systems in various oth- er fields like metallurgy, medicine, and astronomy in ancient India are depicted by historic relics.
Though India had established a measure- ment system since historic times, it var- ied from region to region and empire to empire. During the British India period, various attempts were made to establish uniform units and measurement systems taking into consideration local measure- ment systems like rati, masa, tola, seer, etc. In 1875, 18 European countries and other states signed the Convention du Metre at Paris to accept the common unit

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