World Heritage Day: Iron foundry in Nahargarh and tracing the roots of Metallurgy in India

Excavations in the central Ganges valley and in eastern Vindhya hills have revealed that iron production was in place from as early as 1800 BCE; and by 1000 BCE India had already reached its zenith in the forging of wrought iron

World Heritage Day: Iron foundry in Nahargarh and tracing the roots of Metallurgy in India
For more than 7000 years India has seen skilled metallurgical works dealing with the “seven metals of antiquity”. (Image Courtesy: Mondipa Bose Dey)

By Monidipa Bose Dey

The Jaigarh Fort located on the top of a peak in the Aravalli range stands directly about 400 m above the Amer Fort, and was built with the primary objective of guarding the Amer fort, which was then the chief residence of the Kachhwaha royal family. Jaigarh, which was the chief defensive structure, was connected to the Amer fort by a series of interlinked fortifications, and the two forts were under the Kachhwaha dynasty from around 10th century onwards.

In the 17th century Jaigarh held a highly productive cannon foundry, owing to the presence of iron ore mines near the fort. This foundry in the Jaigarh held a huge wind tunnel that would pull in air from the surrounding hills into its furnace, and the air blast would help create temperatures as high as 1320 °C for melting metals. The molten metal would then be passed onto a reservoir chamber from where it would go into cannon molds in the casting pit. The massive Jaivan Cannon, now on display within the fort premises, was made at Jaigarh fort by Raja Sawai Jai Singh using the foundry and devices inside the fort.

This 17th century show of might using metal weapons made at the iron foundry in Jaigarh was however not a new innovation in the history of Indian metallurgical sciences. For more than 7000 years India has seen skilled metallurgical works dealing with the “seven metals of antiquity” (as the metals that were in use from ancient times are sometimes referred to) more or less in order of discovery: gold, copper, silver, lead, tin, iron and mercury. The earliest evidences of metal work in the Indian subcontinent is  from a pre–Harappan site in Mehrgarh (Baluchistan), where a small copper bead was found that dated to around 6000 BCE, which was of native copper (not the smelted metal type that is extracted from ore). Copper metallurgy took a more advanced form in the Harappan era with its widespread trading networks and the available metal technologies. There are evidences of smelting furnaces from Harappan sites in the northwestern part of the Indian subcontinent. There are also evidences of ancient copper ore mining from the Khetri region of Rajasthan that date to around 3rd-2nd millennium BCE. From archaeological evidences it has been found that the Harappans sourced their copper ores primarily from the Aravalli hills or from Baluchistan and its adjoining areas.

As the metal technology advanced, the Harappans soon figured out the process of making bronze by mixing tin with copper. Bronze is more resistant to corrosion, and while it is harder than copper, it is easier to cast; and when ‘impurities’ such as lead, arsenic, or nickel are added to it the bronze hardens further. From copper weapons, to the true saws, to bronze chisels for dressing stones, to bronze mirrors, bronze figurines (the famous dancing girl of Mohenjo daro), the Harappans were masters at the metallurgical sciences of their times, and used the lost-wax technique for creating their bronze figurines. Harappans also used gold, silver, and electrum (alloy of gold with at least 20% silver) for making various kinds of jewellery.

Post Harappa India saw a Copper Hoard culture that was spread across north and central parts of India, which produced huge amounts of copper tools. Copper and bronze remained a favourite medium for making murtis in India, and the classical age saw the creation of some fine murtis, such as the 500 kg heavy Sultanganj Buddha (dated between 500 and 700 CE) from Bhagalpur in Bihar (now at the Birmingham Museum), which was created using the same lost wax technique used by the Harappans 3000 years back from that time. Later the Chola era saw the production of some of the finest bronze murtis of Hindu deities, especially that of Nataraja Shiva, in the state of TamilNadu.

Excavations in the central Ganges valley and in eastern Vindhya hills have revealed that iron production was in place from as early as 1800 BCE; and by 1000 BCE India had already reached its zenith in the forging of wrought iron. The famous iron pillar in Mehrauli (New Delhi), is dated to the Gupta period of 4th c. CE (by inscription), and is believed to have been made by forging together a number of disc-shaped iron blooms. It remains free from corrosion even today owing to its unique composition- the use of highly pure form of wrought iron, the right amount of phosphorus content, and the proper distribution of slag.

Another major innovation in iron metallurgy of ancient India was the production of wootz steel, highly prized metal in all other ancient cultures of that period. It was produced in south India (Deccan region) from about 300 BCE, by a process where iron was carburized under controlled conditions, and the term wootz (anglicized version of the word ukku, as used by the people of Andhra Pradesh and Karnataka, meaning steel) refers to a high-carbon alloy that is produced by the crucible process. Wootz steel was then exported to Syria, where it was made into ‘Damascus swords’ that were famous for their toughness and sharpness. In the 12th century we find Arab Idrisi telling us, “The Hindus excel in the manufacture of iron. It is impossible to find anything to surpass the edge from Indian steel.” Studies on Wootz have shown that it was likely to have been an ultra-high carbon steel (with 1-2% carbon), and was believed to have been used for making Damascus blades with a watered steel pattern. Experiments in the 1980’s have shown that steel blades with ultra-high carbon steels (around 1.5% Carbon) produce blades with extraordinary superplastic properties (that allow a material to change its external shape to a large extent, without however changing internally). A description of the Damascus blades used during the Crusades tells us that, “One blow of a Damascus sword would cleave a European helmet without turning the edge or cut through a silk handkerchief drawn across it.”

Indian iron production has been in the hands of specific communities known as the Agarias who are ironsmiths, and they are found scattered across the states of Uttar Pradesh, Madhya Pradesh, Bihar, Jharkhand, West-Bengal, Tamil Nadu, and Kerala. Owing to the expertise of these ironsmiths India has been a major exporter of iron from ancient times. In the late 1600s, every year cargo loads of wootz ingots would travel from the Coromandel Coast to Persia. India’s iron and steel industry flourished until the 18th century; and declined after the British started forcing the sale of their own products in India, while at the same time imposing high taxes on products made in India. Finally the start of industrial production of iron and steel acted as the last nail in the coffin to India’s traditional way of iron production that had started its journey in the proto-historic to ancient times.

(The author is a well-known travel and heritage writer. Views expressed are personal and do not reflect the official position or policy of the Financial Express Online.)

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First published on: 17-04-2022 at 14:16 IST