Knowledge Traditions And Practices Of India: Class 11 — Chapter 8: Chemistry and Metallurgy in India

• The Ṛgveda and Yajurveda contain hymns detailing the extraction and processing of metals like gold, silver, copper, tin, lead, iron, and their alloys.
• Ancient Names for Chemistry: Rasāyana Śāstra, Rasatantra, Rasakriyā, and Rasavidyā. These encompassed metallurgy, medicine, cosmetics, glass, dyes, and inks.

अश्मा च मे मृत्तिका च मे गिरयश्च मे पर्वताश्च मे सिकताश्च मे वनस्पतयश्च मे हिरण्यं च मेऽयश्च मे श्यामं च मे लोहं च मे सीसं च मे त्रपु च मे यज्ञेन कल्पन्ताम् ।। यजुर्वेद संहिता – 18/13

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Translation / Analysis: This Yajurveda hymn prays for the abundance of stones, clay, hills, mountains, sand, vegetation, gold, iron, copper, lead, and tin through sacrificial rituals, proving early Vedic familiarity with these materials.

• Construction Materials: Extensive use of baked bricks and gypsum cement containing lime, sand, and traces of $CaCO_3$.
• Pottery and Glazing: Mass production of pottery represents the earliest chemical process of mixing, moulding, and firing. Glazed pottery remains were discovered at Mohenjodaro.
• Faience Production: Harappans produced highly durable faience (glazed ceramic) by partially melting powdered rock quartz in high-temperature kilns using a plant ash flux, regrinding the glassy frit into a paste, and refiring it at approximately $940^\circ\text{C}$.

• Literary Evidence:
  • Suśruta Saṁhitā: Mentions glass crystals, quartz instruments, and beautiful glass vessels for serving food by the 6th century B.C.E.
  • Arthaśāstra of Kauṭilya: Details an advance licence fee for starting a glass industry and mentions using metallic salts and oxides for encrusting glass.
• Foreign Accounts: Pliny noted that Indian glass was superior because of the skilled use of metallic salts and oxides to colour crystals.
• Archaeological Evidence: Glass objects found at Maski (1000–900 B.C.E.), Hastinapur, and Taxila (1000–200 B.C.E.). Glass beads at Harappa date back to 1700 B.C.E. (predating Egyptian glassmaking by 200 years).

• Paints and Dyes:
  • Bṛhatsaṁhitā of Varāhamihira (6th century C.E.): Describes the preparation of glutinous materials for walls and roofs using concentrated plant, fruit, seed, and bark extracts treated with resins. This technology is evident in the long-lasting Ajanta and Ellora cave paintings.
  • Atharvaveda (1000 B.C.E.): Mentions dyestuffs including turmeric, sunflower, madder, orpiment, cochineal, lac, kermes, Kamplcica, Pattanga, and Jatuka.
  • Ṛgveda: Documents leather tanning and cotton dyeing (1000–400 B.C.E.).
• Perfumes and Cosmetics:
  • Bṛhatsaṁhitā: Contains recipes for hair dyes using indigo, iron powder, black iron/steel, and sour rice gruel.
  • Gandhayukti: Describes formulations for scents, mouth perfumes, bath powders, incense, and talcum powder.
  • Aṣṭāṅga Hridaya: Outlines six seasonal cosmetic formulations for body beautification.
  • Dhanvantari Mahal: Established by Raja Serfoji (1788–1832 C.E.) in Thanjavur as a medical research institute. Efficacious recipes were compiled into the Marathi verse text Anubhoga Vaidya Bhāga.

• Chemical Formulations:
  • Caraka Saṁhitā: Mentions the preparation of sulphuric acid, nitric acid, oxides of copper, tin, and zinc, sulphates of copper, zinc, and iron, and carbonates of lead and iron.
  • Rasopaniṣada & Tamil Texts: Describe gunpowder and fireworks mixtures using sulphur, charcoal, saltpetre (potassium nitrate), mercury, and camphor.
  • Rasratnākara of Nāgārjuna: Formulates mercury compounds and details extraction methods for gold, silver, tin, and copper.
  • Cakrapāṇi: Discovered mercury sulphide and invented soap using mustard oil, alkalies, eranda oil, mahua seeds, and calcium carbonate.
  • Rasārṇavam (800 C.E.): Discusses metallurgical furnaces, ovens, crucibles, and metal identification via flame color.
• Paper and Ink Making:
  • Paper: Earliest Indian paper manuscripts survive in the stupas of Kuchar (Central Asia) and Gilgit, dated to the 5th–8th centuries C.E. Chinese traveller I-tsing confirms paper was known in India by the 7th century.
  • Ink: Taxila excavations yielded a 4th-century B.C.E. ink pot. Ink recipes in Rasaratnākara of Nityanātha describe durable black ink made from nuts, myrobalans, and iron pots. Jain manuscripts used ink from roasted rice, lamp black, sugar, and kesurte juice.
• Alcoholic Liquors: Fermentation processes are detailed in the Vedas, Arthaśāstra, and Caraka Saṁhitā (which lists ingredients for making Āsavas).

• Acārya Kaṇāda (born 600 B.C.E., originally named Kaśyapa) formulated the atomic theory 2500 years before John Dalton.
• He authored the Vaiśeṣika Sūtras, defining the smallest indivisible particle of matter as Anu (comparable to molecules) and its constituent units as Paramāṇu (atoms).
• Properties of Paramāṇu: Eternal, indestructible, spherical, suprasensible, and in constant motion in their primordial state. They combine into pairs or triplets (aṇu) driven by unseen forces.

• The concept of extreme metal particle size reduction is detailed in the Caraka Saṁhitā, aligning with modern nanotechnology (structures between 1 and 100 nanometres).
• Bhasmas are herbo-mineral or metallic preparations where metals undergo repeated cycles of burning and cooling (often over 100 times). This process eliminates toxicity, improves bioavailability, and increases shelf life.

• Dating back to the Chalcolithic period, copper and bronze were used for weapons, tools, and ornaments.
• Mohenjodaro Copper: Contained nickel and lead impurities, indicating specific ore sources. Copper was smelted in clay crucibles.
• Aravalli Range: Major copper mining zone (Khetri, Rajpur Dariba). Radiocarbon dating places deep mines in the late 2nd millennium B.C.E.
• Nal Axe: Chemical analysis revealed 94% pure copper and 5% nickel.
• Ahar Excavations (1800–1600 B.C.E.): Discovered copper metallurgical slag, proving indigenous smelting. Copper purity reached 98% (equivalent to modern blister copper).

• Early Iron Smelting: Excavations in the Ganges Valley and Vindhyas date iron smelting to 1800–1000 B.C.E.
• Traditional Tribes: The Agaria and Asur Munda tribes were traditional iron smelters. Agaria furnaces used pre-shaped curved clay bricks with design parameters (shaft taper, bosh angle) remarkably similar to modern 1960s blast furnaces.
• Crucible Steel & Steeling: Ancient blacksmiths mastered carburisation (steeling) to harden iron for weapons. Suśruta (500 B.C.E.) described surgical knives sharp enough to bisect a human hair.
• Wootz Steel: Known as ukku in South India, this high-carbon steel (1.0–1.9% C) was highly prized globally, exported to the Middle East as Damascus steel. King Porus gifted 2.5 tons of Wootz steel to Alexander the Great in 326 B.C.E.
• The Iron Pillar of Delhi: Located at the Qutub Minar complex, this 1600-year-old monument has not rusted despite atmospheric exposure.
  • Composition: 0.15% C, 0.05% Si, 0.05% Mn, 0.25% P, 0.005% Ni, 0.03% Cu, 0.02% N, and >99% Fe.
  • Rust Resistance: Attributed to high metal purity, low manganese/sulphur, and the formation of a protective composite layer of iron hydrogen phosphate.

• Zinc Distillation: Zinc has a low boiling point and vaporises easily during smelting. India was the first country to master zinc distillation at Zawar (Rajasthan, 6th–5th century B.C.E.) using downward distillation in brinjal-shaped retorts.
• Gold and Silver:
  • Gold and silver ornaments found at Mohenjodaro (3000 B.C.E.).
  • The deepest ancient gold mines are located in the Maski region of Karnataka (mid-1st millennium B.C.E.).
  • The Ṛgveda mentions alluvial placer gold in the river Sindhu.
  • Arthaśāstra describes rasviddhā, a naturally occurring gold solution.