In the previous article, we discussed the evolution of chemical practices in India in the pre-Vedic, Vedic and Ayurvedic stages up to 700 CE. The third stage from around 700 CE to around 1100 CE can be considered as a transitional period. Hitherto herbs and vegetable matters were largely employed as drugs, along with some available mineral products. From around 700 CE, we find an increasing use of metallic preparations. Two notable treatises of this period are the Siddhayoga of Vrinda (around 975 CE) and Chakradatta of Chakrapani Dutta (around 1050 CE). Synthetic metallic preparations have received considerable attention in these treatises. Processes which produce sulphides of copper and mercury, iron oxide, potash soap, caustic alkali and so on have been described. Both Vrinda and Chakrapani follow Charaka and Sushruta closely, and also mention Nagarjuna as an authority.
Alchemy is the forerunner of modern chemistry. In other civilisations where alchemy thrived, it was associated with the transmutation of base metals into gold, as well as to the search for the ‘vital elixir of life’. In India, rasashaastra or rasa vidyaa can be considered the broad equivalent of alchemy, but had its own distinctive outlook. Rasa has many meanings, such as essence, taste, sap, juice or semen, but refers to mercury in the context of chemical practices.
Mercury was identified with the male principle (Shiva), while sulphur (gandhaka) was associated with the female principle (Shakti), and most rasashastra texts were presented as a dialogue between Shiva and Shakti in tune with the Tantra philosophy. That is why 700 CE- 1300 CE is considered the Tantric period of Indian chemistry. Nagarjuna, the author of Rasaratnaakara (not later than 8th century CE) stands pre-eminent among the Indian rasavaadins. Rasaarnava (11th or 12th century CE; author unknown) and Rasaratnasamcchaya of Vaagbhata (not later than 14th century) are two of the many important texts after Rasaratnaakara. There is no sharp demarcation between the Tantric period and Iatro-chemical (chemistry associated with healing processes) period (1300 CE – 1600 CE).
In rasashaastra texts, eight mahaarasas, eight uparaasas, seven or eight dhaatus, navaratnas or nine precious stones, and poisons are the broad categories of chemical substances which are discussed. The numbers in each category stated above are only indicative, as they vary across the texts. The eight mahaarasas or major substances are: mica, tourmaline copper pyrite, iron pyrite, bitumen, copper sulphate, zinc carbonate, and mercury.
The eight uparasas or minor substances are sulphur, red ochre, iron sulphate, alum, orpiment (arsenic trisulphide), realgar (arsenic sulphide), collyrium (compounds of antimony), and tintstone or cassiterite (tin dioxide). Navaratnas or nine gems include pearl, topaz, emerald, ruby, sapphire and diamond. Gold, silver, copper, iron, lead, tin and zinc are the seven dhatus or metals. A few alloys such as brass, bronze and panchalohas or combinations of five metals are also included at times. Among poisons (visha) are some minerals and herbs, substances of animal origin and even undesired combinations of drugs.
Indian rasavaadins developed processes leading to different chemical compositions which involve the use of a number of minerals, metals and gems, as also certain medicinal plants which were naturally available. The details as given in the rasashaastra texts concerning their classification, methods of purification and the like show they must have arrived at them through protracted experimental methods over a long period.
We give some quotations from the texts. “Gold, silver, copper, iron, tin and lead, these are six metals and their resistance to rusting is in the order in which they have been mentioned.” (Rasaarnava)
“Leaves of teekshnaloha (cast iron, steel) are repeatedly to be heated and plunged into water and then to be powdered in a stone mortar with an iron pestle. The powder of iron thus obtained is to be roasted 20 times in a covered crucible in combination with mercury and sulphur, and after each roasting the powder of iron is to be pounded as directed above – iron thus reduced to ashes is to be used in medicine.” (Rasaratnasamucchaya) “Bell-metal is obtained by melting 8 parts of copper and 2 parts of tin together.” (Rasaratnasamucchaya)
Mercury occupied the pride of place in rasashaastra, and mercurial preparations were supposed to bestow long life and youthful vigour. In practice, some Ayurvedic and Siddha medicines were derived from various metals and minerals like cinnabar (mercuric sulphide) for instance. However this was only after these had undergone complex purificatory processes including rubbing with medicinally efficacious plant juices and extracts and incorporation of sulphur, mica, alkaline substances, etc., so as to remove toxic effects.
The rasashaastra texts carefully spell out the layout of the laboratory, and also various yantras for heating, steaming, distilling, and extracting substances. Indian chemical traditions were rich and varied which resulted in considerable practical applications in metallurgy, gemmology and medicine.
The two articles on Indian chemistry have been largely based on Acharya P.C. Ray’s ‘History of Hindu chemistry’ , Prof. B.V. Subbarayappa’s article in ‘A concise history of science in India’, a CBSE textbook on ‘Knowledge traditions and practices of India’ and lectures by Prof.B.N. Jagtap, IIT Bombay.
M S Sriram
Theoretical Physicist & President, Prof K V Sarma Research Foundation
(sriram.physics@gmail.com)