Eternal India Encyclopedia

Eternal India encyclopedia

Ancient Concepts, Sciences & Systems

CHEMICAL PRACTICES AND ALCHEMY

Valley Civilization had perfected the art of pottery to a high degree of perfection. Terracotta doll making was another craft of the Indus Valley Civilization which involved production of human figurines that were entirely fashioned by hand. Metal craft was not prevalent very much during the pre-Indus Valley culture, though there are evidences of the use of copper in a few places like Kalibangan. But the Indus Valley Civilization can boast of highly skilled metalsmiths who fashioned artefacts out of copper, bronze, lead, silver, gold and electrum (an alloy of gold and silver). Gold was used primarily for ornaments. Metal crafting pro- cedures such as soldering, sheet making, rivetting, coiling and lost- wax metal casting process (cire perdue casting) were known to the Indus Valley metalsmiths. Copper sheets were fashioned into vessels, while bronze was used for casting. The bronze statue of the ‘dancing girl’ discovered at Mohenjodaro was probably a lost wax cast product, even though excavations have not revealed mould casts.

Chemical practices as a purposeful and useful skill have a hoary antiquity in India. The first indication of chemistry at work in ancient India is with the baking of clay and production of pottery. Even though pottery making appears to be an artist’s work in creativity, in reality it reflects the development of processes which involve heating, fusion, evaporation and the treatment of minerals. Some of the chemical practices for which ancient India was famous are : metal working, mineral processing, composition of mortar and ce- ment, brewing of fermented drinks, extraction of oils, production and use of vegetable pigments and dyes and glass blowing. PREHISTORIC Pottery making was widely prevalent in India even prior to 1500 B.C. But this pottery was mainly handcrafted and not made by using the potter’s wheel. There were no kilns to bake the pots, but the pots were kept in a circular pit and covered partially with sherds. These were then lighted to raise a small fire. Handcrafted, improperly baked pots have been found in excavations of prehistoric rock shelters at Lekhalia in Mirazpur district of Uttar Pradesh, Nagarjunakonda of Andhra Pradesh etc. In the Indus Valley Civilization, also called the Harappan cul- ture which flourished from 2300.-1750 B.C. pottery making had reached a very sophisticated level. Excavations at Kalibangan, a site in the Ganganagar district of Rajasthan, have revealed wheel- made pots in the red and black washings. Kalibangan is regarded as pre-Harappan culture (2600-2400 B.C.) and the presence of wheel-made pots is an indication that the potter’s wheel is more ancient than the Indus Valley Civilization. The pottery of the Indus Valley Civilization is wheel made, comprising of the variously coloured (red, buff, grey) alluvial soil of the Indus river bank. The pots were painted in black colour over a red surface. Mica, sand and lime were used for tempering the pots. Pots were baked in kilns using wood or charcoal for firing purposes. The kilns were round, cylindrical or pear shaped with or without brick layering. That the potters of the Indus Valley Civilization were highly skilled craftsmen can be seen from the intricate decorative designs carved on the pots. The designs consist of plant or animal forms, geometrical shapes like squares and triangles and occasionally human figures also. The technique of glazing the surface of the pottery was also known to the Indus Valley potter. Glazing mate- rials such as finely crushed quartz or white sand, glassy-flux and colouring matter were mixed with gums and other organic sub- stances to create a shiny polished surface. According to Mackay, an archaeological expert on Mohenjodaro, the potters of the Indus

Metals, particularly copper and bronze, were widely used to manufacture hand tools like axes, chisels, drills, reamers, metal mirrors and weapons like daggers, knives, spears, arrowheads etc. Even though the metallic instruments had some percentage of tin, alloying perhaps had not been perfected by the metalsmiths. How- ever there are indications that metalcraft techniques like cold work- ing and annealing were known to the metalsmiths. One of the most surprising aspects in the Indus Valley Civilization however is the absence of iron objects indicating that iron metallurgy was un- known. Other chemical practices of the Indus Valley Civilization include the use of gypsum and lime as plastering material to cover the walls made out of burnt brick. Many minerals such as lapis luzuli, turquoise,alabaster, haematite, agate etc were used for ornamental purposes. VEDIC AGE This is the most distinctive phase in the cultural history of ancient India which perhaps began at a period not earlier than 1500 B.C and thought to be post-Harappan in time. The people of the Vedic age generally known as Indo Aryans have left written records (in the form of Samhitas, Aranyakas, Upanishads etc) from where we can get glimpses of chemical practices of that period. The RigVeda, hailed as the earliest ever human writing, men- tions Ayas meaning metal. Silver and gold plates were used for sacrificial rites. Atharva Veda opines that gold ensures longevity

Painted Grey ware : dish (Ahicchatra) and bowl (Panipat)