Indian Contributions to Science PDF

INDIAN CONTRIBUTIONS TO SCIENCE Compiled By Vijnana Bharati Indian Contributions To Science Indian Contributions To Science Compiled by Vijnana Bharati All rights reserved. No part of the publication may be reproduced in whole or in part, or stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical photocopying, recording, or otherwise without the written permission of the publisher. For information regarding permission, write to: Vijnana Bharati A-4, First Floor, Gulmohar Park, New Delhi- 110 049 Fourth Edition 2019 Contents Preface...................................................................................................vii Vidyarthi Vigyan Manthan (VVM Edition –XI) 2022-23................ix Acknowledgement..................................................................................xi 1. India’s Contribution to Science and Technology..................1 (From Ancient to Modern) 2. Astronomy in India....................................................................9 3. Chemistry in India: A Survey................................................. 20 4. The Historical Evolution of....................................................30 Medicinal Tradition in Ancient India 5. Plant and Animal Science in Ancient India..........................39 6. Mathematics in India............................................................... 46 7. Metallurgy in India..................................................................58 8. Indian Traditional Knowledge on......................................... 69 Environmental Conservation 9. Ayurveda for Life, Health and Well-being: A Survey........81 10. Nobel Laureates of Indian Origin & Inspiring................89 Lives of Scientists and their contribution 11. Conventional, Non-conventional and................................. 131 Clean Energy Sources of India 12. Science and Its Various Branches........................................137 13. Ayurveda and Medicinal Plants.........................................141 14. Indigenous Agriculture, Biotechnology............................. 149 and Nano –technology 15. Traditional Wisdom of Astronomy..................................... 154 16. India in Space: A Remarkable Odyssey.............................. 165 17. Discovery of Gravitational Waves—................................... 178 The Indian Contributions 18. Discovering Samgamagrama Madhavan...................... 180 19. Latest Achievements July 2016 Onwards..................... 184 Syllabus:  Junior group (Class VI- VIII): Chapters 1-7 & 9-12  Senior group (Class IX- XI): All Chapters (Chapters 1-19) vi Preface This piece of work on the India’s contribution to the knowledge of science has been specifically prepared for Vidyarthi Vigyan Manthan. It portrays the achievements of India in science and technology since the ancient times. The evolution of India as a unique society can be attributed to the ancient concept of vasudaiva kutumbakam, meaning the whole world is one family. This unity had aroused feelings of to tolerance towards freedom of expression and knowledge. Rishis like Varahamihira, Aryabhatta, Vagbhatta, Susruta contributed towards the proliferation of knowledge of highest value and had put India at the forefront of all scientific developments and advancement. In fact, owing to the immense royal patronage provided for science, advancement of its knowledge and application of science in daily lives became a common factor in Indian society. When the whole of western society was in darkness, India rose high and shone as the ‘golden sparrow’ of the globe. The discovery of various scientific facts and the development of scientific concepts and technologies gave rise to a new age that could keep India in the forefront of the knowledge hub for centuries. The most important and indestructible wealth is knowledge’ and an individual with a quest to acquire knowledge is believed to be truly on the path of enlightenment and liberation. Vidyarthi Vigyan Manthan intends to groom students of today, like you, to lead India as tomorrow’s scientists, technocrats and innovators. Therefore, it is important for students to know our rich and glorious past. Each one of you should imbibe in you the vision of our ancient scientists and sages who could achieve highly with available resources. They were people of great vision, value, wisdom, purity and compassion. Students would feel inspired from the generosity with which the benefit of such scientific knowledge was shared for social and national progress. Hence, it is extremely important that India retains its position as the spearhead of the global scientific fraternity. The spark has already been ignited by our great scientists like Ramanujan, C.V. Raman, Vikram Sarabhai, APJ Abdul Kalam and various organizations like ISRO, CSIR, DRDO, and so on. There is abundant talent in India and it needs to be utilized effectively and efficiently. I strongly feel that it is the duty of every parent and teacher to encourage students to think innovatively. The eagerness and spirit of scientific temperament should be developed in students. The task is accomplishable if you all strive for it. The goal is certainly not far away. Vande Mataram! Dr. Sudhir S. Bhadauria Secretary General, Vijnana Bharati viii VIDYARTHI VIGYAN MANTHAN (VVM EDITION –XI) 2022-23 “INDIA’S LARGEST SCIENCE TALENT SEARCH FOR NEW INDIA USING DIGITAL DEVICES” Vidhyarthi Vigyan Manthan (VVM) is a national science talent search programme for New India organized by VIBHA (Vijnana Bharati), in collaboration with NCERT – Ministry of Education and Vigyan Prasar - an autonomous organization of the Department of Science and Technology, Government of India. VVM is a National program for educating and popularizing science among school students of VI to XI standards. VVM aims to identify and nurture the bright minds among the student community, who are keen on subjects related to science. OBJECTIVES OF VIDYARTHI VIGYAN MANTHAN (VVM): To create interest among students in pure science. To educate school children about India’s contributions from traditional to modern to the world of science and technology. To provide hands-on-training to students through workshops and other events. To conduct an annual talent search exam at the national level to identity students who have a scientific bent of mind. To provide the winning students with mentors to enrich science learning experience to carry forward their science education at higher levels. To organize exposure visits for the winners to various R & D institutions in the country. To identify successful students at the state and national levels and felicitate them with prizes and certificates. The successful students will also be mentored appropriately, which will help them to progress further with higher education in science. The present study material is only indicative of the range of topics that will be covered in the test. However one should understand that the material along with the books named Life of Sir C. V. Raman & India'a Freedom Struggle and Science-II provided by Vijnana Bharati, covers only 40% of the VVM syllabus in exam. Therefore, the organizers appeal to all students to explore further reading materials in order to prepare well for the test. Evaluation of student will be based on their individual performance at entry level. The examination will be conducted in English, Hindi along with 10 major regional languages. The organizers wish you all the very best…….!!! x Acknowledgements Vijnana Bharati gratefully acknowledges the contribution of the individuals and organizations involved in the development of this Book- “INDIAN CONTRIBUTIONS TO SCIENCE”. This is infact solely is the initiative of Vijnana Bharati to introduce literature prepared with material from ancient to modern period specially highlighting the contribution of India in the field of Science & Technology as a reading material for Vidyarthi Vigyan Manthan talent search examination. Vijnana Bharati is grateful to CBSE- Ex Advisors- Shri Vineet Joshi (Ex Chairman), Dr Sadhana Parashar, Ex Director (Academics & Training), Convener Prof Jagbir Singh- All the members of Material Production Team of K.T.P.I, co-ordinator, supporting members (CBSE)and Editors Prof. Kapil Kapoor and Prof. Michel Danino. Vijnana Bharati sincerely acknowledges the contributions of the Academic Committee members VVM who participated in the review of the manuscript. The team of VVM is highly thankful to its National Convener for his support throughout the re-making of the book. The contribution of office and administrative staff, computer staff of VVM is also gratefully acknowledged. The efforts of the publication Department- VIBHA in bringing out this publication are also appreciated. 1 India’s Contribution to Science and Technology (From Ancient to Modern) A dvancements in science and technology have been the major reason for the development of human civilization. India has been contributing to the fields of science and technology since ancient times. Even today, what we term as ‘traditional knowledge’ is actually based on scientific reasoning. Pre-Independence The history of scientific discoveries and development in India dates back to the Vedic era. Aryabhatta, the famous mathematician of the Vedic era, invented ‘zero’. It is believed that ancient Indian scholars had developed geometric theorems before Pythagoras had made them popular. The concept of squares, rectangles, circles, triangles, fractions, and the ability to express number 10 to the 12th power, algebraic formulae, and astronomy have all had their origins in Vedic literature; some are stated to have been known as early as 1500 BCE. The decimal system was already in use during the Harappan Civilization. This is evident in their use of weights and measures. Moreover, the concepts of astronomy and metaphysics are all described in the Rig Veda, an ancient Hindu text of the Vedic era. From the complex layout of Harappan towns to the existence of the Iron Pillar in Delhi, it is evident that India’s indigenous technologies had been very sophisticated. They included the design and planning of water supply, traffic flow, 2 Indian Contributions to Science natural air conditioning, complex stone work and construction engineering. The Indus Valley Civilization was the world’s first to build planned towns with underground drainage, civil sanitation, hydraulic engineering and air-cooling architecture. While other ancient civilizations of the world were small towns with one central complex, the Indus Valley Civilization had the distinction of being spread across a region about half the size of Europe. Weights and linguistic symbols were standardized across this vast geography, for a period of over 1000 years, from around 3000 BCE to 1500 BCE. Water Management Water has been the life blood of most major civilizations. Criss-crossed by many great rivers, India is no exception to the rule. Indians had been developing water management techniques even before the Harappan time. Wells, ponds, lakes, dams and canals have been constructed with advanced technologies throughout the historic timeline of Indian civilization. Water has been used for storage, drinking and purposes of irrigation. It is estimated that even today, there are more than a million man-made ponds and lakes in India. Iron and Steel Iron and steel have literally been the pillars of modern civilization. Ancient India was pioneer in developing the technology of producing rust-free iron. This metal from India was famous in contemporary Europe for sword making. The famous Iron Pillar of Delhi is a testimony to that technology which is almost rust free even today. Farming Technique and Fertilizers Indian farming technology was mostly indigenously developed and was ahead of its time. It included soil testing techniques, crop rotation methods, irrigation plans, application of eco friendly pesticides and fertilizers, storage methods for crops, etc. India’s Contribution to Science and Technology 3 Physics The concept of atom can be traced to the Vedic times. The material world was divided into five elements, namely, earth (Prithvi), fire (Agni), air (Vayu), water (Jal) and ether or space (Akasha). Paramanu (beyond atom) was considered to be the smallest particle, which cannot be divided further. Nuclear energy is produced today splitting the same. Medicine and Surgery Ayurveda (Ayur means life, Veda means knowledge) is probably the oldest structured system of medical science in the world. Proper knowledge about various ailments, diseases, symptoms, diagnosis and cure is the basis of Ayurveda. Many scholars like Charaka and Susruta have made invaluable contribution to Ayurveda by inscribing in written form, as found in ancient manuscripts. Shipping and Shipbuilding Shipbuilding was one of India’s major export industries till the British dismantled it and formally banned it. Medieval Arab sailors purchased boats from India. Even the Portuguese, instead of buying from Europe, also obtained their boats from India. Some of the world’s largest and most sophisticated ships were built in India and China. The compass and other navigation tools were already in use in India, much before Europe. Using their expertise in the science of maritime travel, Indians participated in the earliest known ocean-based trading system. Post-Independence India has witnessed considerable growth in the field of science and technology post Independence. Significant achievements have been made in the areas of nuclear and space science, electronics and defense. India has the third largest scientific and technical manpower in the world. In the field 4 Indian Contributions to Science of Missile Launching Technology, India is among the top five nations of the world. Science and technology was brought into the mainstream of economic planning, with the establishment of the Department of Science and Technology (DST) in May 1971. DST, today, promotes new areas in science and technology and plays the role of a nodal department for organizing, coordinating and promoting science and technology in the country. Our country’s resources are used to get maximum output in the field of agriculture and industry. Indian scientists are making path-breaking research in the fields of agriculture, medicine, biotechnology, cold regions research, communications, environment, industry, mining, nuclear power, space and transportation. Now, India has the expertise in the fields of astronomy and astrophysics, liquid crystals, condensed matter physics, molecular biology, virology, and crystallography, software technology, nuclear power and defense research and development. Atomic Energy The main objective of India’s nuclear energy programme is to use it to generate power, and apply the technology for further progress in agriculture, medicine, industry and research. India is, today, recognized as one of the most advanced countries in nuclear technology. Accelerators and nuclear power reactors are now designed and built indigenously. Space Indian Space Research Organization (ISRO) is the sixth largest space research organization in the world. It has numerous milestones to its credit since its establishment in 1969. India’s first satellite Aryabhatta was built by ISRO in 1975. It was followed by many more. In 2008, Chandrayaan-1 became India’s first mission to the moon. The Indian Space Research Organization (ISRO), under the Department of Space (DOS), is responsible for research, development and operation in the India’s Contribution to Science and Technology 5 space through satellite communications, remote sensing for resource survey, environmental monitoring, meteorological services, and so on. India is the only Third World country to develop its own remote-sensing satellite. Electronics and Information Technology The Department of Electronics plays promotional role for the development and use of electronics for socio-economic development. Application of electronics in areas such as agriculture, health and service sectors has also been receiving special attention. For upgrading the quality of indigenously manufactured products, a series of tests and development centres and regional laboratories have been set up. These centres for electronic design and technology help small and medium electronics units. Information Technology (IT) is one of the most important industry in the Indian economy. The IT industry of India has registered huge growth in recent years. India’s IT industry grew from 150 million US dollars in 1990/91 to a whopping 500 billion US dollars in2006/07. In the last ten years, the IT industry in India has grown at an average annual rate of 30%. Oceanography India has a coastline of more than 7,600 km and 1,250 islands. The Department of Ocean Development was established in 1981 to ensure optimum utilization of living resources, exploitation of non-living resources such as hydrocarbons and minerals and production of ocean energy. Two research vessels, FORV Sagar Kanya and FORV Sagar Sampada, are assessing and evaluating the resource potential. Surveys and exploration efforts have been directed to assess sea bed topography, and concentration and quality of mineral nodules. India has sent 13 scientific research expeditions to Antarctica since 1981, and has established a permanently manned base, Dakshin Gangotri. A second permanent station, 6 Indian Contributions to Science an entirely indigenous effort, was completed by the eighth expedition. The objective was to study the ozone layer and other important constituents like optical aurora, geomagnetic pulsation and related phenomena. The National Institute of Ocean Technology has been set up for the development of ocean-related technologies. Biotechnology India has been the frontrunner among the developing countries in promoting multidisciplinary activities in this area, recognizing the practically unlimited possibility of their applications in increasing agricultural and industrial production, and in improving human and animal life. The National Biotechnology Board was formed in 1982. The Department of Biotechnology was created in 1986. The areas which have been receiving attention are cattle herd improvement through embryo transfer technology, in vitro propagation of disease- resistant plant varieties for obtaining higher yields and development of vaccines for various diseases. Council of Scientific and Industrial Research The Council of Scientific and Industrial Research (CSIR) was established in 1942, and is today the premier institution for scientific and industrial research. It has a network of 40 laboratories, two cooperative industrial research institutions and more than 100 extensions and field centres. It plays a leading role in the fulfilment of the technological missions supported by the government. *** Follow Guide to Pronunciation (Chapter 2 to 6) In this course, we have used diacritical marks for words in Sanskrit and other Indian languages, that is to say, accents, dots and macrons. This is necessary in order to get their pronunciation right. Should you find those marks disconcerting at first, just keep in mind these few simple and easy principles:  A macron (¯) over a vowel makes it long; for instance rāga is pronounced raaga.  The letter c stands for ‘ch’- as in ‘Caraka’, pronounced ‘Charaka’.  ś (as in ‘Suśruta’) and ş (as in nakşatra) may be pronounced more or less as ’sh’ in ‘shall’. Thus Śulbasūtra is pronounced shulbasootra.  The letter ŗ(as in smŗti) may be roughly pronounced as ri, but keeping the’ i’ as brief as possible.  Other dotted consonants (d, ţ and ņ mainly) are ‘hard’, that is, pronounced by hitting the tongue on the palate. Thus ‘Āryabhata’ is pronounced ‘aaryabhatta’ with a hard sounding ‘tt’. Undotted consonants are soft, with the tongue on the teeth. For instance, in ganita, ni is hard, but ta is soft. Students who wish to know the precise correspondence between diacritics and the Devanagari alphabet may refer to the following two tables, for vowels and consonants: 8 Indian Contributions to Science In every ancient culture, astronomy was born before mathematics: there is, in fact, no need of maths to look at the sky, observe the periodicity of the moon’s phases, of a few identifiable planets, the northward or southward journey of the sunrise on the eastern horizon through the year, or to trace imaginary lines between the stars. 9 2 Astronomy in India The Beginnings of Indian Astronomy And that is indeed how the story of astronomy always begins. In India, those beginnings are not adequately documented. The first ‘astronomical’ objects, found in the Andamans, belong to the palaeolithic era, some 12,000 years ago; they are calendar sticks noting the waxing and waning* of the moon by incising daily notches on a wooden stick. One of the calendar sticks found in the Andaman islands, apparently recording lunar phases across several months *The apparent increase (waxing) and decrease (waning) of the moon’s disc from new moon to full moon and back, in the course of a lunar month. 10 Indian Contributions to Science Some of the rings stone found at Mohenjo-daro, with rows of small drilled holes that appears to point to the sunset across the year. (Courtesy: Erkka Maula) Patterns of rock art found in Kashmir, such as a double sun or concentric circles, have convinced some scholars that they were depictions of a supernova and meteor showers respectively, perhaps witnessed some 7,000 years ago. Ring- stones found at Mohenjo-daro, the largest city of the Indus civilization (2600-1900 BCE), which exhibit rows of small drilled holes, have been interpreted as calendrical devices keeping track of the sunrise at different times of the year. The perfect east– west alignment of streets in the same city has been attributed to the sighting of the star cluster Pleiades (Kṛttikā). While the above statements remain speculative, it is well recognized that ancient people everywhere felt a need to relate to the universe by tuning in to the rhythms of celestial objects. A few thousand years ago, the Rig-Veda, the oldest of the four Vedas, spoke of a year of 360 days divided into twelve equal parts and used a five-year yuga (era), probably as a first attempt to reconcile the lunar and solar years (by the addition of a month after those five years). It clearly recorded a solar eclipse, although in a metaphorical language. And it has recently been proposed that its mention of ‘3,339 gods’ was actually a reference to the 18-year cycle of eclipses known as the saros; if so, this points to a very early tradition of astronomical observation. A few centuries later, the Yajur-Veda considered a lunar year of 354 days and a solar year of 365 days, and divided the year into six Astronomy in India 11 The 27 nakṣatras, with the earth in the centre. (Courtesy: M.S. Sriram) ṛtus or seasons of two months each. The Yajur-Veda also gave the first list of 27 nakṣatras or lunar mansions, that is, constellations along the path of the moon on the celestial sphere. Because of the need to keep time for the proper conduct of rituals, calendrical astronomy grew more sophisticated in the late Vedic period, with the Vedāṅga Jyotiṣa of Lagadha as its representative text (and, if we may call it so, the first extant Indian scientific text). On the basis of its own astronomical data, it has been dated between the 12th and the 14th centuries BCE by most scholars. The length of the sidereal day (i.e. the time taken by the earth to complete one revolution with respect to any given star) it uses is 23 h 56 min 4.6 s, while the correct value is 23 h 56 min 4.091 s; the tiny difference is an indication of the precision reached in that early age. The Vedāṅga Jyotiṣa also discusses solstices (ayanānta) and equinoxes (viṣuva) and uses two intercalary lunar months (adhikamāsa) to catch up with the solar calendar.* In some ways, this text remains the foundation for India’s traditional luni-solar calendars. *The solar year is about 365.24 solar days, while the lunar year is, at most, 360 days. After a few years, the difference between the two will grow so much that a month needs to be added to the lunar year to restore a broad coincidence between the two systems. This is the intercalary month. 12 Indian Contributions to Science The Early Historical Period The second period extended from the 3rd century BCE to the 1st century CE and was marked by astronomical computations based on the risings and settings of planets, their revolutions, etc. Jain astronomy also developed in this period, based on a peculiar model of two sets of 27 nakṣatras, two suns and two moons; it nevertheless resulted in precise calendrical calculations. This is also the period when huge scales of time were conceived of such as a ‘day of Brahmā’ (or kalpa) of 4.32 billion years, which curiously comes close to the age of the earth (4.5 billion years). Of course, there are much longer time scales to be found in Jain texts and in the Purāṇas. While some scholars have discerned Babylonian and Greek influences at play during this and the next periods, the issue remains open. Nevertheless, such influences seem clear enough in the introduction of the seven-day week a few centuries BCE (late Vedic India divided the month only into two lunar fortnights or pakṣa, one light and one dark), and of the zodiac of 12 signs (rāśi), first recorded in the Yavanajātaka (c. 269 CE). The Siddhāntic Era There are many gaps in our knowledge after the above period and before the start of what has been called the golden age of Indian mathematics and astronomy. Beginning in the 5th century CE, this is the Siddhāntic era, when texts called siddhāntas were composed — a Sanskrit word meaning ‘principle’ or ‘conclusion’, but which applies here to a collection of conclusions or a treatise. Their chief characteristics were the use of trigonometric methods and epicyclic* models for the computations of planetary positions. *Because they were using a geocentric system, early Greek and Indian astronomers could not explain the planets’ occasional retrograde motion (as seen from the earth); they assumed that the planets moved along smaller orbits, called epicycles, whose centres revolved around the earth along larger circles (the planets’ mean orbits). Astronomy in India 13 Āryabhaṭa I (born 476 CE), working near what is today Patna, ushered in this era with his Āryabhaṭīya, which dealt concisely but systematically with developments in mathematics and astronomy. Among other things, it discussed units of time and features of celestial sphere, described the earth as a rotating sphere hanging in space, and produced a table of the planets’ mean positions. Āryabhaṭa also gave a correct explanation for both lunar and solar eclipses, and stated that the diameter of the earth is 1,050 yojanas (defining the yojana as 8,000 average human heights or about 13.6 km); this is close to the actual dimension, though 12% too large. (His diameters for the planets and the sun are however much too small.) Many brilliant astronomers followed, dealing with issues of coordinate systems, time measurement and division, mean and A map showing some of India’s astronomers / mathematicians. Their dates of birth as well as their place of birth or work are often approximate. Note that many more names, from Baudhāyana (~ 600 BCE) to Śrīdhara (~ 800) or Āryabhaṭa II (~ 950), simply cannot be placed on the map, as the texts are silent on their locations. (Courtesy: Michel Danino, compiled from various sources) 14 Indian Contributions to Science true positions of celestial bodies, and eclipses. Varāhamihira, Āryabhaṭa’s contemporary, composed in 505 CE a collection of five astronomical texts prevalent during his time; one of the five texts, the Sūrya Siddhānta, was revised later and became a fundamental text of Indian astronomy; two others expounded the principles of Greek astronomy. Varāhamihira extensively discussed the revolutions of planets, eclipses, and the zodiac, often with an astrological background. Bhāskara I (b. 600 CE), the earliest known exponent of Āryabhaṭa I, provided a very useful elucidation of Āryabhaṭa’s astronomy, besides improved calculation methods. A manuscript of a passage of Brahmagupta’s Brahmasphuta Siddhānta. (Courtesy: Bombay University Library) A few years later, Brahmagupta (born 598 CE), who lived near Mount Abu, mistakenly rejected Āryabhaṭa view of the earth as rotating sphere, but contributed much to calculations of the mean and true longitudes of planets, conjunctions and problems of lunar and solar eclipses, applying to all these his considerable mathematical skills. * *The celestial longitude of a celestial body (planet or star) is the arc of the ecliptic measured eastward from the vernal equinox (Aries) to the point where the ecliptic is intersected by the great circle passing through the body. (The ecliptic is the plane of the earth’s orbit.) ‘Mean longitude’ refers to an average value, i.e. the body’s average position, while ‘true longitude’ refers to its actual position at a given time. Astronomy in India 15 Indian astronomers could not have achieved so much without a strong tradition of observation, and the 22nd chapter of Brahmagupta’s magnum opus, the Brahmasphuta Siddhānta, dealt with a variety of astronomical instruments, most of which could be easily made by any good craftsman: among them, a water clock (ghaṭī yantra) consisting of a bowl with a small hole at the bottom, which would sink in exactly 24 minutes (a ghaṭī) if placed over water; a gnomon ( a short stick kept vertically for the study of the motion of its shadow); a graduated disk or half-disk; and a scissor-like pair acting as a compass. Those instruments and the computational techniques applied to them were both adopted by later scholars, beginning by Lalla of the 8th century. Some of the instrum ents described by Lalla for astronomical o bservations. (Courtesy: S hekher Narveker) Brahmagupta also authored a manual of astronomical calculations which remained popular for centuries, as testified by Al-Biruni, the Persian savant who came to India in the 11th century as part of Mahmud of Ghazni’s entourage. Al-Biruni was deeply interested in Indian astronomical techniques, wrote about them at length, and translated texts by Varāhamihira and Brahmagupta into Arabic or Persian. 16 Indian Contributions to Science Bhāskara II (b. 1114), better known as Bhāskarāchārya, brought important innovations to both astronomical and mathematical techniques, discussing in particular the mean and true positions of planets, the triple problem of time, direction and place, the risings and settings and conjunctions of the planets, eccentric and epicyclic theories for their motions of planets, and a large number of astronomical instruments. Over all, Bhāskarāchārya greatly improved upon the formulas and methods adopted by earlier Indian astronomers. Inscription of 1128 CE recording King Ratnadeva’s donation of a village to astronomer Padmanābha for predicting a total lunar eclipse. Over 350 such inscriptions, from 440 to 1859, have been traced out. (Courtesy: B.V. Subbarayappa) During those centuries, astronomy’s interface with the general public was mostly through calendars and pañcāṅgas (almanacs), and the prediction of eclipses, which had great religious and social significance. Indeed, an astronomer’s fame was guaranteed if he could accurately predict the occurrence, nature and duration of eclipses, and numerous inscriptions record a king’s reward to such an astronomer. Another interface was architecture, and many temples show clear astronomical alignments with events such as the sunrise at solstices and equinoxes. Astronomy in India 17 The Sringeri temple, whose mandapa is de dicated to the twelve rāśis o r signs of the zodiac; some of the pil lars are align ed to the sunrise on the two solstices. (Courtesy: B.S. S hylaja) The Kerala School The widespread belief that there was virtually no progress in Indian astronomy and mathematics after Bhāskara II is based on a general ignorance of the intense developments that took place in the southern state of Kerala. The so-called ‘Kerala School of astronomy and mathematics’ flourished there from the 14th to the 17th century, when networks of knowledge transmission in north India were severely disrupted in the wake of repeated invasions. Parameśvara (c. 1362-1455), an author of some thirty works, was one of the foremost astronomers of this School, and the founder of the dṛk system, which improved computations of eclipses and the positions of the planets and proved to be very popular. He emphasized the need to regularly correct formulas to bring them closer to actual observations, and was said to have studied eclipses and their parameters over a period of years. He was followed by Nīlakaṇṭha Somayājī (1444-1545), who, in his landmark Tantrasaṅgraha, carried out a major revision of the older Indian planetary model for the inferior planets, Budha (Mercury) and Śukra (Venus), and described them, along 18 Indian Contributions to Science with Maṅgala or Kuja (Mars), Bṛhaspati or Guru (Jupiter) and Śani (Saturn), as moving in eccentric orbits around the sun. This achievement of the Kerala school of astronomy is truly remarkable in the light of the fact that Nīlakaṇṭha preceded Copernicus (1473-1543), the propounder of the heliocentric theory in Europe. It seems unlikely, however, that Indian heliocentrism directly influenced European advances in the field. Other Post-Siddhāntic Developments About the same time, a complex interface with Islamic astronomy took place, which, among other benefits, brought instruments such as the astrolabe to India. The famous and massive yantramantra or Jantar Mantar observatories built in the early 18th century by the Maharaja of Jaipur, Sawai Jai Singh (1688-1743), represent a convergence between Indian, Arabic and European astronomy. In a general way, Indian astronomers were more interested in efficient methods of computation than in theoretical models. Some of the techniques used to calculate planetary positions and Astronomy in India 19 Two views of New Delhi’s Jantar Mantar. (Courtesy: Michel Danino) eclipses yielded remarkably precise results and impressed by their speed European astronomers such as Le Gentil, a French savant who stayed in Puducherry for two years to observe a solar transit of Venus in June 1769. Although traditional tables and even calculation methods survived well into the nineteenth century (witness the case of the Odiya astronomer, Sāmanta Candraśekhara Simha, who was completely insulated from European astronomy and authored in 1869 a voluminous Siddhānta), the introduction of modern astronomy brought to a close India’s own developments in this science. But India, in many ways, had contributed to the growth of the new science, as some of the techniques developed by Indian astronomers and mathematicians had been relayed to Europe centuries earlier through the Arabs. Indeed, Indian astronomy interacted not only with Islamic (or Zīj) and European astronomies, but also with Chinese astronomy, in complex interplays that invariably enriched both players. 3 Chemistry in India: A Survey Chemistry, as we understand it today, is a relatively young discipline; it took shape in 18th -century Europe, after a few centuries of alchemical tradition, which was partly borrowed from the Arabs. (Alchemy was a semi-esoteric practice whose ultimate goal was to turn base metals into gold and discover an ‘elixir of life’ that would grant immortality.) Other cultures — especially the Chinese and the Indian — had alchemical traditions of their own, which included much knowledge of chemical processes and techniques. Early Chemical Techniques In India, we can trace such techniques all the way to the Indus civilization (3rd millennium BCE) and its antecedents. The Harappans’ metallurgical skills have been described in the A bleached bead from Harappa (courtesy: J.M. Kenoyer). Chemistry in India: A Survey 21 module on Metallurgy in India. Pottery called for a control of processes such as heating, fusion and evaporation. Bead-making involved complex treatments of minerals, including bleaching a bead with a solution of calcium carbonate, then heating it in a kiln, so as to leave permanent white designs on it. Harappans also experimented with various mortars and cements made of burnt limestone and gypsum, among other components. Finely crushed quartz, once fired, produced faience, a synthetic material; it was then coated with silica (perhaps fused with soda) to which copper oxide was added to give it a shiny turquoise glaze. Faience was then shaped into various ornaments or figurines. The addition of iron oxide gave a greenish blue tint to glazed pottery, while manganese oxide resulted in a maroon colour. Such techniques survived the end of the Indus civilization and found their way to the later Ganges civilization (1st millennium BCE), often with innovations — glass manufacture, for instance: numerous glass beads and other artefacts have been unearthed from Taxila in the Northwest to Nalanda in the East and Arikamedu in the South. A Harappan Bangle made of faience 22 Indian Contributions to Science Pigments were another area for skilled chemical practices, and were required for painting (witness the famous Ajanta murals) as well as dyeing of cotton and othertextiles. Interestingly, sources of pigments were not limited to organic materials (such as extracts of specific flowers or fruits) but included mineral sources, from carbon (lamp black) to arsenic sulphide (yellow ochre) or copper acetate (verdigris, greenish- blue in colour). Atomism in Vaiśeṣika Although it did not translate into actual chemistry, the Indian notion of atomism deserves a brief mention. Atomism, or the concept that matter is ultimately made of indivisible building blocks, appeared in India a few centuries BCE as part of philosophical speculations, in particular in the Vaiśeṣika, one of the six philosophical systems of ancient India. The author of the Vaiśeṣika Sūtras came to be known as Kaṇāda (literally ‘eater of particles’) and may have lived any time after 500 BCE. In this system, all substance was seen as an aggregated form of smaller units called atoms (aṇu or paramāṇu), which were eternal, indestructible, spherical, supra -sensible and in motion at the primordial state; they could form pairs or triplets, among other combinations, and unseen forces caused interactions between them. The Vaiśeṣika system identified nine types of substance (dravya): (1 to 5) the five elements (earth or prithvi, water or ap, fire or tejas, wind or vāyu, ether or ākāśa), (6) time (kāla), (7) space or direction (dik), (8) the mind (manas), and (9) the spirit or knower (ātman). Besides, substance had twenty-four different qualities (guṇas), including fluidity, viscosity, elasticity and gravity. While fluidity was related to water, earth and fire, viscosity was unique to water, and gravity to earth. Distinctive characteristics of sound, heat and light were also discussed, which often came close to later discoveries of physics, although, lacking a mathematical apparatus, they did not evolve into scientific theories. Chemistry in India: A Survey 23 Chemistry in Early Literature We find plentiful evidence of knowledge of chemical practices in some of India’s early literature. Kauṭilya’s Arthaśāstra is a well-known text of governance and administration authored probably in the 3rd or 4th century BCE, during the Mauryan era. It has much data on prevailing chemical practices, in particular a long section on mines and minerals (including metal ores of gold, silver, copper, lead, tin and iron). It also discusses the various characteristics of precious stones (pearl, ruby, beryl, etc.), details of fermented juices (from sugarcane, jaggery, honey, jambu, jackfruit, mango, etc.), and oil extraction. The fundamental two texts of Ayurveda are the Caraka Saṃhitā and the Suśruta Saṃhitā, both dated a few centuries CE. Not only do they turn to a wide range of chemicals for medical use — metals, minerals, salts, juices — but they also discuss the preparation of various alkalis (kṣāra), which is regarded as one of the ‘ten arts’ (kalā). Alkalis are described as mild, caustic or average and are prepared from specific plants: after the plants have been burnt together with some limestone, their ashes are then stirred in water, filtered, and the resulting solution is concentrated by boiling, to which burnt limestone and conch shells are added. Such alkalis were used to treat surgical instruments as well as thin sheets of metals like iron, gold or silver intended for the preparation of drugs. These texts also speak of organic acids extracted from plants such as citrus or tamarind (an awareness of mineral acids came much later). Varāhamihira’s Bṛhat Saṃhitā, an encyclopaedia of sorts composed in the 6th century CE, has a chapter on the preparation of numeous perfumes out of sixteen fundamental substances mixed in different proportions. Indeed, perfumery and cosmetics formed a major branch of chemical practices in classical and medieval India. The Bṛhat Saṃhitā also includes various recipes, for instance for the preparation of a glutinous material to be applied on the roofs and walls of houses and temples; it was prepared 24 Indian Contributions to Science entirely from extracts from various plants, fruits, seeds and barks which, after being boiled and concentrated, were then treated with various resins. It would be interesting to test and scientifically assess such recipes. Several texts (such as the Kāmasūtra) contain a list of the traditional sixty-four arts which an accomplished person was supposed to master. Among them, interestingly, we find, ‘Knowledge of gold and silver coins, jewelsand gems; chemistry and mineralogy; coloured jewels, gems and beads; knowledge of mines and quarries,’ which testifies to the attention paid to such fields. The Classical Age Alchemy in India emerged around the mid-first millennium CE, during the Gupta empire. Its origins remain hard to trace, and scholars have proposed that it received inputs from China, where the discipline is well attested as early as in the 2nd century CE. Whatever its beginnings, Indian alchemy soon took a stamp of its own. It was variously called rasaśāstra, rasavidyā or dhātuvāda; the word rasa has many meanings, such as essence, taste, sap, juice or semen, but in this context refers to mercury, seen as one of the most important elements. Mercury was identified with the male principle (Shiva), while sulphur (gandhaka) was associated with the female principle (Shakti), and most alchemical texts were presented as a dialogue between Shiva and Shakti. (Intriguingly, the genders of mercury and sulphur are the other way round in Chinese alchemy!) This is in tune with the Tantra philosophy, and indeed, in alchemical practices, preparations and processes, mercury was regarded as divine and assumed to be potent enough to confer not only longevity but also occult powers, including invisibility and levitation. There is a vast alchemical literature, authored by savants such as Nāgārjuna, Govinda Bhāgavat, Vāgbhata, Somadeva, Yaśodhara, among many others. The rasaśāstra texts discuss many chemical substances and their interactions. They were categorized as follows (with some variations): Chemistry in India: A Survey 25  mahārasas or eight major substances: mica, tourmaline, copper pyrite, iron pyrite, bitumen, copper sulphate, zinc carbonate, and mercury (sometimes lapis lazuli and magnetite or lodestone are included);  uparasas or eight minor substances: 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, including pearl, topaz, emerald, ruby, sapphire and diamond;  dhātus or seven metals: gold, silver, copper, iron, lead, tin, zinc; a few alloys (such as brass, bronze and combinations of five metals) were also included; poisons (viṣa or garala) and plants; among the latter, over 200 are named in the texts (their identification is not always certain); plants were required, in particular, to treat or ‘digest’ metals and minerals. In the quest for the elixir of life, mercurial preparations were supposed to bestow long life and youthful vigour; mercury was sometimes called amṛtadhātu or ‘immortal metal’. In practice, some Ayurvedic and Siddha medicines were derived from various metals and minerals, but only after those had undergone complex purificatory processes so as to remove their toxic effects (or ‘kill’ them, as the texts say) and make them fit for internal use. For instance, although mercury compounds are regarded as poisonous, cinnabar (mercuric sulphide, HgS) went through eighteen complex processes (saṃskāras), including rubbing with various medicinally efficacious plant juices and extracts, incorporation of sulphur, mica, alkaline substances, etc. The resulting mercury compound was then declared fit for consumption and believed to lead to the body’s rejuvenation. Similar processes existed in Tamil alchemy and the Siddha system of medicine, which developed, in addition, special techniques in connection with naturally occurring salts, especially three of them (muppu), consisting of rock salts and various carbonates. 26 Indian Contributions to Science Native cinnabar or mercuric sulphide Transmuting base metals, such as lead, tin or copper, into gold was another pursuit of alchemy, and involved five operations: smearing, throwing, pouring, fumigating and impact. Here again, mercury, sometimes called svarṇakāraka or ‘maker of gold’, often played a major role. The processes described in the texts are quite elaborate, extending to many days; their precise details cannot often be followed, however, as there are uncertainties about some plants, minerals, or their treatments. But transmutation was not regarded as a purely mechanical process: honesty, self-control, sincerity of purpose,devotion to God, obedience to the guru and faith in rasavidyā were regarded as essential for the rasavādin to achieve success. Actual practices were kept secret, as the goal would fail to be reached if they were divulged to the uninitiated. devotion to God, obedience to the guru and faith in rasavidyā were regarded as essential for the rasavādin to achieve success. Actual practices were kept secret, as the goal would fail to be reached if they were divulged to the uninitiated. Claims of actual production of gold out of base metals extend to recent times, such as a 1941 demonstration recorded on a marble slab at New Delhi’s Lakshminarayan temple; naturally, Chemistry in India: A Survey 27 such claims must be viewed with the greatest scepticism. More likely, the colour of the metal was so altered that it appeared golden; indeed, some texts refer to gold-looking alloys of silver, copper and mercury. In the alchemical tradition, the transmutation of metals may also be taken as a metaphor for the body’s own transmutation through the elixir of life, which was the ultimate objective of Indian alchemists. In any case, the quest for this elixir or the transmutation of base metals did lead to actual and valuable chemical techniques, in the medical field in particular, and eventually contributed to the Ayurvedic and Siddha pharmacopoeias. Laboratory and Apparatus The texts carefully spell out the layout of the laboratory, with four doors, an esoteric symbol (rasaliṅga) in the east, furnaces in the southeast, instruments in the northwest, etc. Besides mortars (of stone or iron) and pestles, bellows (to heat the furnaces), sieves, pans, tongs, scissors and earthen or An artist’s view of an alchemical laboratory or rasasala 28 Indian Contributions to Science glass vessels, the apparatus included specialized instruments ingeniously developed for heating, steaming, distilling, triturating or extracting substances. Let us mention just a few of them:  the mūsa yantra or crucible, usually made of white clay or of the earth of an anthill mixed with rice husk, iron dust, chalk, etc.; such crucibles would have various shapes and sizes, depending on their application;  the koṣṭhi yantra, for the extraction of ‘essences’ of metals, consisting of two rimmed vessels, with fire urged from above and a side blower; besides the metals, the vessels would be filled with charcoal;  the svedanī yantra, a big earthen vessel used for steaming;  the dolā yantra, in which a pot is half-filled with a liquid and a suspended substance absorbs the liquid’s vapours; A representation of the koṣṭhi yantra (left) and the dolā yantra (right) (Courtesy: National Science Centre, New Delhi)  the pātana yantra, for sublimation or distillation; it could be upward, downward or sideways; the second was the ādhana yantra, in which a paste of mercury was coated at the bottom of the upper vessel, allowing vapours to descend into the lower vessel and combine with substances kept there;  the dhūpa yantra, used for fumigation of gold leaves or silver foils with fumes of sulphur or other substances Chemistry in India: A Survey 29 A representation of the ādhana yantra (left) and the dhūpa yantra (right) (Courtesy: National Science Centre, New Delhi) Altogether, India’s chemical traditions were rich and varied, and fused elaborate techniques with a spiritual component. Although they may not have directly contributed to the birth of modern chemistry, they did result in considerable practical applications, especially in fields like metallurgy, gemmology and medicine. 4 The Historical Evolution of Medicinal Tradition in Ancient India Specialization into eight branches The history of medicine in India spans a period of several thousand years, definitely dating back to a few centuries before the Common Era. There is evidence that the earliest textbooks of Ayurveda like Caraka Saṃhitā (General Medicine), Suśruta Saṃhitā (Surgery), and Kāśyapa Saṃhitā (Paediatrics) were edited and revised several times over a thousand years. They attained their current form in the first few centuries of the Common Era. It is an amazing fact that so early, Sanskrit texts were composed dealing exclusively with specialties like Paediatrics, Surgery, Ophthalmology, ENT and so on. In these texts, Ayurveda is already seen in a developed form specialized into eight branches: General Medicine, Surgery, Ophthalmology-ENT-Dentistry, Paediatrics, Psychiatry, Toxicology, Rejuvenative Medicine and Reproductive Medicine. Around the 6th or 7th centuries CE, the renowned physician Vāgbhaṭa compiled the specialized knowledge of the eight branches of Ayurveda into one compendium; the larger version is known as Aṣṭāṅga Saṃgraha and the shorter version is called Aṣṭāṅga Hṛdaya. The tradition of surgery The tradition of surgery in Ayurveda has a long history. Researchers at the University of Missouri-Columbia discovered that physicians in ancient India had developed technology to The Historical Evolution of Medicinal Tradition in Ancient India 31 A mesolithic (15,000 – 6,000 BCE) rock painting from Bhimbetka, Madhya Pradesh seems to depict surgery being performed on a subject’s head or eye. drill teeth and remove decay 8,000 to 9,000 years ago. Study of fossils from Mehrgarh, now in Pakistan, revealed tiny holes drilled into teeth on the biting surface of male molars. Evidence has also been unearthed from Harappa and Lothal revealing an ancient surgical practice on a Bronze Age skull dating back to nearly 4,300 years ago. Trepanation, a common means of surgery practised in prehistoric societies starting with the Stone Age, involved drilling or cutting through the skull vault, often to treat head injury or to remove bone splinters or blood clots caused by a blow to the head. A folio from a manuscript of the Suśruta Saṃhitā, an Ayurvedic textbook on various surgical procedures and surgical instruments. (Courtesy: Wellcome Library, London) 32 Indian Contributions to Science The saga of Indian surgery continued to flourish and reached its acme in the time of Suśruta, who is believed to have lived in the 2nd century BCE. Suśruta is now revered as the father of surgery and advocated a thorough study of anatomy by dissecting the dead body. He introduced the method of sterilizing surgical instruments to prevent sepsis after surgical procedures. The compendium of Suśruta describes hundreds of sharp and blunt surgical instruments and many of them resemble instruments used by surgeons today. Suśruta is recognized for having developed innovative surgical procedures like reconstruction of the nose or rhinoplasty through plastic surgery, use of a specific species of ants as dissolvable sutures to close the intestines, surgical removal of cataract, and surgical management of urinary calculi. Medical and surgical implements of 19th century origin from India. (Courtesy: Science Museum, London) The Historical Evolution of Medicinal Tradition in Ancient India 33 This painting shows Suśruta’s disciples learning surgery by working on vegetables This painting by James Wales, commissioned in 1794 by two British surgeons, was published along with the first known description of plastic surgery in the West. (Courtesy: Wellcome Institute, London) 34 Indian Contributions to Science The Indian rhinoplasty technique was (re)discovered by Western medicine in the 18th century, when the East India Company surgeons Thomas Cruso and James Findlay witnessed Indian rhinoplasty procedures at the British Residency in Poona. The surgeons published photographs of the procedure and its nasal reconstruction outcomes in the October 1794 issue of the Gentleman’s Magazine of London. An oculist treating a patient with specialized instruments.(Painting of 1825, courtesy The British Library, London) Medical genetics in Ayurveda In the Caraka Saṃhitā one comes across the earliest reference to the genetic basis of diseases. Caraka points out that the reproductive element is composed of seeds (bīja) which are further divided into parts (bījabhāga) and subparts The Historical Evolution of Medicinal Tradition in Ancient India 35 (bījabhāgāvayava). Each part or subpart of a seed represents a particular organ of the body and damage to the part can damage the organ. Inoculation for smallpox In the 18th century, British officials and travellers observed and documented the practice of inoculation for smallpox, which was in vogue in India centuries before vaccination was discovered by Edward Jenner. In an account written for London’s College of Physicians, J.Z. Holwell, who studied and himself practised the Indian method of inoculation, testified to its great effectiveness in preventing the occurrence of smallpox. Microbiology and parasitology There are references to microbial life in textbooks of medicine like Caraka Saṃhitā dating back to several centuries before the Common Era. Lower life forms were classified into pathogenic and non-pathogenic. The pathogenic organisms include microbes that cannot be seen with the naked eye. Technical nomenclature was developed for different types of microbes and their shapes and sizes have also been described. How those physicians were able to provide such descriptions, or even conceive of microbes, centuries before microscopes were invented remains a mystery. Communicable diseases and epidemics Suśruta Saṃhitā describes communicable diseases and explains that disease can be transmitted from one person to the other by close contact, through air, sharing of clothes, sleeping together and so on. Fumigation is mentioned as a measure to prevent infectious diseases from spreading. Caraka Saṃhitā devotes an entire chapter to epidemiology and prescribes methods to prevent epidemics as well as manage the outbreak of epidemics. During the period of King Aśoka, an efficient public healthcare system was established. 36 Indian Contributions to Science An evolving pharmacopoeia The practice of medicine in Ayurveda is based on the principle that there is no substance in the world that does not potentially have medicinal property. The evolution of Ayurvedic pharmacopoeia represents a continuous and unfinished quest for discovering new medicines from natural resources. About 1,500 medicinal plants have been described and formulated into thousands of medicines in the tradition of Ayurveda. Hundreds of animals and animal products have also been mentioned in the texts. Around the 6th century in the Common Era, the branch of medicine specializing in the use of minerals and metals known as Rasaśāstra developed and established itself, especially in the North of India. The older tradition of herbal medicines continued to be practised in India’s southern states. In Tamil Nadu, the system of Siddha medicine (traditionally regarded as having been founded by eighteen ‘Siddhars’ or realized beings, but in practice similar to Ayurveda) added to its pharmacopoeia drugs metallic and mineral components. Pluralistic approach to healthcare Ayurveda nurtured a pluralistic approach to healthcare in India. From ancient times, healthcare in India developed in This painting shows an Ayurvedic surgeon attending to a wound with his surgical instruments. (Courtesy: Wellcome Library, London) The Historical Evolution of Medicinal Tradition in Ancient India 37 the two streams of the folk and classical expressions. India has a rich tradition of folk medicine, which was organized into a paramedical force of health practitioners, bonesetters, poison healers and birth attendants who delivered primary healthcare for the people. Many of these traditions have survived into modern times. Today India is perhaps the only country in the world that officially recognizes a pluralistic healthcare system patronizing medical systems like Ayurveda, Yoga and Naturopathy, Unani, Siddha and Homoeopathy. Cross-cultural interactions Ayurveda benefited from cross-cultural interactions and spread out of India into neighbouring countries like China, Sri Lanka, Tibet, Thailand and Indonesia. Buddhism played a major role in the spread of Ayurveda outside India. When Alexander the Great invaded India in 325 BCE, he was so impressed by the snakebite healers and Ayurvedic physicians that he invited them to Greece. There is historical evidence indicating interactions between the physicians of Greek medicine and Ayurveda. Important textbooks of Ayurveda like Caraka Saṃhitā, Suśruta Saṃhitā and Aṣṭāṇga Hṛdaya were translated into Tibetan, Persian and Arabic languages in the Middle Ages. Travellers from China and the Middle East narrated in their accounts the advanced state of medical practice in India. A dynamic literary tradition The history of Ayurveda reveals the evolution of a vibrant and dynamic medical tradition with compendia, medical lexicons, pharmacopoeias, handbooks, manuals of treatment and so on being composed at important chronological and geographical landmarks. For example, in the 8th century CE, a treatise devoted exclusively to diagnostics was composed by Mādhava known as Mādhava Nidāna. In the 11th century, a new treatise was composed on dietetics by Viśvanātha Sena called Pathyāpathyaviniścaya. In the 13th century the Śārngadhara Saṃhitā was composed on the subject of pharmacy and pharmaceuticals, providing the first description of the physiology of respiration. When pulse diagnosis was introduced in Ayurveda, independent treatises were composed on the subject. This tradition of constant updating and documentation of medical knowledge continued without a break right up to the colonial period. In the 19th century, Ayurveda suffered a setback when unfavourable policies and regulations were enforced by the colonial rulers. However, with the publication of the main Ayurvedic texts, a revival set in around the turn of the 20th century, with a few leading Indian scholars coming out in defence of the discipline. Global resurgence of Ayurveda In the post-independence period, Ayurveda’s resurgence continued, and in recent years it has been gaining prominence as a whole system approach to healthcare under the banner of Complementary and Alternative Medicine. Although it is not the West, Ayurveda is taught and practised in many countries like Germany, Italy, United Kingdom, Austria, Netherlands and so on. There are many schools of Ayurveda in the United States. Contemporary status Ayurveda Continues to manage a wide range of conditions effectively like chronic degenerative diseases and life style disorders and is being sought after by people around the globe. As the world is moving towards an integrative approach to healthcare, Ayurveda continues to inspire visions of healing that is holistic, pluralistic and integrative at the same time through a tradition that has exhibited remarkable continuity, resilience and adaptiveness to the vicissitudes of time. 5 Plant and Animal Science in Ancient India Ayurveda also represent Life Sciences like Botany, Zoology, Veterinary Science and agriculture along with medicine. Plant science was known as Vrksayurveda and Animal science as Mrgayurveda. Asvayurveda and Gajayurveda represent Veterinary Medicine for horses and elephants respectively. Agriculture was known as Krsisastra. Plant Science in Ancient India Antiquity and continuity Knowledge of plants and agricultural practices are documented in ancient Indian literature. Discussions on plant science can be seen in Vedic literature, the epics and various compendia. Sources Arthasastra of Kautilya contains very interesting passages relating to the harvesting and management of crops and crop diseases and very many aspects of agroforestry. Brhat Samhita of Varahamihira composed in the 6th Century CE has an entire chapter devoted to Vrksayurveda. Agni Purana also includes a chapter on the topic. Cakrapanidatta, a commentator of the celebrated Ayurvedic text, Caraka Samhita, puts forth the theory that plants have feelings and cognitive abilities. There 40 Indian Contributions to Science are also independent works on the subject like Surapala’s Vrksayurveda and Upavana Vinoda of Sarngadhara. The legacy of Vrksayurveda has also been preserved through folk traditions in oral form. The farming and tribal communities constitutes the largest repository of the working knowledge of plant science in India. Surapala applied the dosa theory to plants to provide a number of recipes for plant protection and treatment, depending on the particular dosa imbalance affecting the plant. Many of the ingredients he lists have been shown to possess antimicrobial properties. Among them are milk (elephant milk at times!), ghee, honey, licorice, cow urine and dung, various liquid manures, mustard, pastes made of various barks and roots, asafetida, turmeric, sesame oil, salt and ash; the flesh, fat or marrow from various animals (mammals and fish) was also recommended in specific cases. Folios from the manuscript of Vrksayurveda of Surapala, a text on plant science composed in the 10th century. (Courtesy: Asian Agri-History Foundation, Secunderabad) Plant and Animal Science in Ancient India 41 Scope Ayurvedic literature refers to plants and their classification into forest trees, other trees, shrubby plants and herbs. Shrubby plants are either climbers or shrubs as such and herbs are flowering and non- flowering. Flowering and an non-flowering trees are also distinguished. Vrksayurveda includes topics like collection, selection and storage of seeds, germination and sowing, various techniques of plant propogation and grafting, nursing and irrigation, testing and classification of soil, selection of soils suitable for various plants, types of plants, manuring, Preparation of extract from neem kernels to treat crops against pests and diseases. (Courtesy: Centre for Indian Knowledge Systems, Chennai) Preparation of extract from garlic, ginger and chilli to treat crops against pests and diseases. (Courtesy: Centre for Indian Knowledge Systems, Chennai) 42 Indian Contributions to Science pest and disease management, nomenclature and taxonomy, description and classification of plants to get varied purposes, favorable and unfavorable meteorological conditions. Use of plants as indicators of weather, water, and minerals as well as botanical marvels. Validation The Indian Council of Agricultural Research (ICAR) has documented 4,879 indigenous practices in the field of traditional plant science. A set of 111 indigenous technical practices were selected and subjected to experimental testing and validation in efforts that were conducted by several ICAR institutes and state agricultural departments and universities across the country. These pertain to various topics such as pest control, crop protection, farm implements, weather forecasting etc., and it was shown that slightly more than 80% of these practices were valid and about 6% were partly valid. Vrksayurveda promises many new areas for fresh research initiatives like the study of meteorological conditions (tithi, naksatra) that are suitable for various agricultural operations in the cultivation of crops, increasing plant growth and yield, testing and classification of soil and use of plants as indicators for water, minerals and weather. Animal Science in Ancient India Antiquity and continuity The branch of veterinary medicine was well developed in ancient India and was devoted to the well being of domesticated animals like cows, horses and elephants. Earliest references can be seen in vedic literature. Sources Hayayurveda of Salihotra is an ancient textbook of veterinary medicine that classifies horse and describes Plant and Animal Science in Ancient India 43 (Left) A veterinary surgeon performing surgery on the eye of a horse. (Right) A veterinary surgeon performing bloodletting on a horse. (Courtesy: Wellcome Library, London) treatments for horses apart from providing accounts of anatomy. Salihotra composed many treatises on horses, which were translated into Arabic, Persian and Tibetan. A treatise on Gajayurveda devoted to elephants was composed by Palakapya which deals with treatment of diseases afflicting elephants. The Mrgapaksisastra by Hamsadeva composed in the 13th century CE gives fascinating descriptions of animals and birds. Scope The diversity of animal life has been well captured in the ancient literature of India. The canons of Caraka and Susruta classify animals on the basis of their habitat and predatory behaviour. Animals are classified on the basis of habitat into terrestrial, underground, aquatic, aerial and marshy types. Animals are prey snatchers (prasaha), peckers (viskira) or attackers (pratuda). In different text, animals have been classified 44 Indian Contributions to Science on the basis of varied criteria. Animals are reproduced sexually (yonija) or asexually (ayonija). Sexual reproduction is either through eggs (oviparous) or placenta (viviparous). The texts also speak of life emerging from moisture and heat as well as from head vegetation. One classification distinguishes animals by number of feet and another by the presence or absence of hoofs. The Matsyapurana classifies animals on the basis of their activity into diurnal, nocturnal or both. A number of animals have been described in the context of food and dietetics. The medicinal and nutritional properties of meat from a variety of animal sources have been documented in the classical text of Ayurveda. The food web and food chain have been described highlighting the principle that one form of life is food for another (jivo jivasya jivanam). People of ancient India lived in close proximity with nature and were ken observers of animal life. It has been mentioned in some text that the first clues regarding medicinal properties of plants can be discovered from animal behaviour. Thus ancient Indian literature has one of the earliest documented evidence of the practice of zoo-pharmacognosy, that is, the discovery of medicinal uses of plant by observing how animals eat specific plants when they suffer from a disease, have worm or have been bitten by a snake. The texts of Ayurveda also talk about confirming the toxicity of substances by administering test doses to animals, perhaps the earliest account of animal experiments in toxicology. Current status Gajayurveda is still practiced by traditional experts in states like Kerala. Veterinary herbal medicines are manufactured and marketed by pharmaceutical firm in India. Biodiversity and folk traditions The richness of the biodiversity and the climatic and geographic variations were highlighted in ancient writings. Different geographical regions were described along with the Plant and Animal Science in Ancient India 45 cycle of six seasons setting the stage for variations in biodiversity. It is mentioned in Ayurvedic texts that there is a variation of biodiversity in term of flora and fauna as well as human life and habits over a span of 12 yojanas or 96 miles. Ancient Indians estimated that there are nearly 8.4 million yonis or species of life on earth. This comes strikingly close to the recent estimate of modern scientists at 8.7 million species. Susruta proclaims that one must hunt for the earth is bountiful everywhere. There are about 4,600 ethnic communities in India who have lived in close proximity with nature and nurtured a folk system of medicine. It is estimated that there are one million specialized carries of folk medicine, outnumbering the paramedics on the payroll of the government. 6 Mathematics in India As early Indian astronomers tried to quantify the paths of the sun, the moon, the planets and the stars on the celestial sphere with ever more accuracy, or to predict the occurrence of eclipses, they were naturally led to develop mathematical tools. Astronomy and mathematics were thus initially regarded as inseparable, the latter being the maid-servant of the former. Indeed, about 1400 BCE, the Vedāṅga Jyotiṣa, the first extant Indian text of astronomy, states in two different versions: Like the crest on the head of a peacock, like the gem on the hood of a cobra, jyotiṣa (astronomy) / gaṇita (mathematics) is the crown of the Vedāṅga śāstras [texts on various branches of knowledge]. In fact, jyotiṣa initially referred to astronomy and mathematics combined; only later did it come to mean astronomy alone (and much later did it include astrology). First Steps India’s first urban development, the Indus or Harappan civilization (2600-1900 BCE), involved a high degree of town planning. A mere glance at the plan of Mohenjo-daro’s acropolis (or upper city), Dholavira (in the Rann of Kachchh) or Kalibangan (Rajasthan), reveals fortifications and streets generally aligned to the cardinal directions and exhibiting right angles. Specific proportions in the dimensions of major structures have also been pointed out. All this implies a sound knowledge of basic geometric principles and an ability to measure angles, which the discovery of a few cylindrical compasses made of shell, with slits cut every 45°, has confirmed. Besides, for trading purposes Mathemathics in India 47 A few Harappan weights made of chert, from Dholavira, Gujarat (Courtesy: ASI) the Harappans developed a standardized system of weights in which, initially, each weight was double the preceding one, then, 10, 100 or 1,000 times the value of a smaller weight. This shows that the Harappans could not only multiply a quantity by such factors, but also had an inclination for a decimal system of multiples. However, there is no agreement among scholars regarding the numeral system used by Harappans. There is no scholarly consensus on the dates of the four Vedas, India’s most ancient texts, except that they are over 3,000 years old at the very least. We find in them frequent mentions of numbers by name, in particular multiples of tens, hundreds and thousands, all the way to a million millions in the Yajur Veda — a number called parārdha. (By comparison, much later, the Greeks named numbers only up to 10,000, which was a ‘myriad’; and only in the 13th century CE would the concept of a ‘million’ be adopted in Europe.) The Brāhmanas, commentaries on the Vedas, knew the four arithmetical operations as well as basic fractions. 48 Indian Contributions to Science Early Historical Period The first Indian texts dealing explicitly with mathematics are the Śulbasūtras, dated between the 8th and 6th centuries BCE. They were written in Sanskrit in the highly concise sūtra style and were, in effect, manuals for the construction of fire altars (called citis or vedis) intended for specific rituals and made of bricks. The altars often had five layers of 200 bricks each, the lowest layer symbolizing the earth, and the highest, heaven; they were thus symbolic representations of the universe. The first layer of one kind of śyenaciti or falcon altar described in the Śulbasūtras, made of 200 bricks of six shapes or sizes, all of them adding up to a specified total area. Because their total area needed to be carefully defined and constructed from bricks of specified shapes and size, complex geometrical calculations followed. The Śulbasūtras, for instance, are the earliest texts of geometry offering a general statement, in geometric form, of the so-called Pythagoras theorem (which was in fact formulated by Euclid around 300 BCE). They spelt out elaborate geometric methods to construct a square resulting from the addition or subtraction of two other squares, or having the same area as a given circle, and vice-versa — the classic problems of the squaring of a circle or the circling of a square (which, because of π’s transcendental nature, cannot have exact geometrical solutions, only approximate ones). All Mathemathics in India 49 The geometrical expression of the Pythagoras theorem found in the Śulbasūtras. these procedures were purely geometrical, but led to interesting corollaries; for instance, √2 was given a rational approximation which is correct to the fifth decimal The Śulbasūtras also introduced a system of linear units, most of them based on dimensions of the human body; they were later slightly modified and became the traditional units used across India. The chief units were: 14 aṇus (grain of common millet) = 1 aṅgula (a digit) 12 aṅgulas = 1 prādeśa (the span of a hand, later vitasti) 15 aṅgulas = 1 pada (or big foot) 24 aṅgulas = 1 aratni (or cubit, later also hasta) 30 aṅgulas = 1 prakrama (or step) 120 aṅgulas = 1 puruṣa (or the height of a man with his arm extended over his head) 50 Indian Contributions to Science A few centuries later, Piṅgala’s Chandasūtras, a text on Sanskrit prosody, made use of a binary system to classify the metres of Vedic hymns, whose syllables may be either light (laghu) or heavy (guru); rules of calculation were worked out to relate all possible combinations of light and heavy syllables, expressed in binary notation, to numbers in one-to-one relationships, which of course worked both ways. In the course of those calculations, Piṅgala referred to the symbol for śūnya or zero. About the same time, Jaina texts indulged in cosmological speculations involving colossal numbers, and dealt with geometry, combinations and permutations, fractions, square and cube powers; they were the first in India to come up with the notion of an unknown (yāvat-tāvat), and introduced a value of π equal to √10, which remained popular in India for quite a few centuries. Numerals as they appeared in early inscriptions, from the 3rd century BCE to the 1st century CE. Note that they do not yet follow a decimal positional system; for instance, in the first column, 40 is written as ‘20, 20’, 60 as ‘20, 20, 20’. (Adapted from INSA) Mathemathics in India 51 With the appearance of the Brāhmī script a few centuries BCE, we come across India’s first numerals, on Ashoka’s edicts in particular, but as yet without any decimal positional value. These numerals will evolve in shape; eventually borrowed by Arabs scholars, they will be transmitted, with further alterations, to Europe and become our modern ‘Arabic’ numerals. Evolution of Indian numerals, as evidenced by inscriptions. The first script, Brāhmī, was used by Aśoka in his Edicts; the last is an antecedent of the Devanagari script. (Adapted from J.J. O’Connor & E.F. Robertson) The Classical Period Together with astronomy, Indian mathematics saw its golden age during India’s classical period, beginning more or less with the Gupta age, i.e. from about 400 CE. Shortly before that period, the full-fledged place-value system of numeral notation — our ‘modern’ way of noting numbers, unlike non-positional systems such as those depicted above or Roman numbers — had been worked out, integrating zero with the nine numerals. It is a pity that we shall never know who conceived of it. Amongst the earliest known references 52 Indian Contributions to Science to it is a first-century CE work by the Buddhist philosopher Vasumitra, and it is worked out more explicitly in the Jain cosmological work Lokavibhāga, written in 458 CE. Soon it was adopted across India, and later taken to Europe by the Arabs. This was a major landmark in the world history of science, since it permitted rapid developments in mathematics. One of the first attested inscriptions (from Sankheda, Gujarat) recording a date written with the place-value system of numeral notation. The date (highlighted) reads 346 of a local era, which corresponds to 594 CE. (Adapted from Georges Ifrah) About 499 CE, living near what is today Patna, Āryabhaṭa I (born 476 CE) authored the Āryabhaṭīya, the first extant siddhānta (or treatise) attempting a systematic review of the knowledge of mathematics and astronomy prevailing in his days. The text is so concise (just 121 verses) as to be often obscure, but between the 6 th and the 16th century, no fewer than twelve major commentaries were authored to explicate Āryabhaṭa introduced the notion of a and build upon its contents. half-chord, a substantial advance over It was eventually translated Greek trigonometry, which considered into Arabic about 800 CE the full chord of an arc of circle. Mathemathics in India 53 (under the title Zīj al-Ārjabhar), which in turn led to a Latin translation in the 13th century (in which Āryabhaṭa was called ‘Ardubarius’). The mathematical content of Āryabhaṭīya ranges from a very precise table of sines and an equally precise value for π (3.1416, stated to be ‘approximate’) to the area of a triangle, the sums of finite arithmetic progressions, algorithms for the extraction of square and cube roots, and an elaborate algorithm called kuṭṭaka (‘pulverizing’) to solve indeterminate equations of the first degree with two unknowns: ax + c = by. By ‘indeterminate’ is meant that solutions should be integers alone, which rules out direct algebraic methods; such equations came up in astronomical problems, for example to calculate a whole number of revolutions of a planet in a given number of years. It is worth mentioning that despite its great contributions, the Āryabhaṭīya is not free of errors: its formulas for the volumes of a pyramid and a sphere were erroneous, and would be later corrected by Brahmagupta and Bhāskarācārya respectively. The Classical Period, post-Āryabhaṭa Born in 598 CE, Brahmagupta was an imposing figure, with considerable achievements in mathematics. In his Brahmasphuta Siddhānta, he studied cyclic quadrilaterals (i.e., inscribed in a circle) and supplied the formula for their area (a formula rediscovered in 17 th -century Europe): if ABCD has sides of lengths a, b, c, and d, and the semi-perimeter is s = (a + b +c + d)/2, then the area is given by: Area ABCD = √[(s – a) (s –b) (s – c) (s – a)] Brahmagupta boldly introduced the notion of negative numbers and ventured to define the mathematical infinite as khacheda or ‘that which is divided by kha’, kha being one of the many names for zero. He discovered the bhāvanā algorithm 54 Indian Contributions to Science for integral solutions to second-order indeterminate equations (called varga prakriti) of the type Nx2 + 1 = y2. He was in many ways one of the founders of modern algebra, and his works were translated into Persian and later Latin. Dated around the 7 th century, the Bakhshali manuscript, named after the village (now in northern Pakistan) where it was found in 1881 in the form of 70 leaves of birch A few leaves from the Bakhshali manuscript (Courtesy: Wikipedia) bark, gives us a rare insight into extensive mathematical calculation techniques of the times, involving in particular fractions, progressions, measures of time, weight and money. Other brilliant mathematicians of the siddhāntic era included Bhāskara I, a contemporary of Brahmagupta, who did pioneering work in trigonometry (proposing a remarkably accurate rational approximation for the sine function), Śrīdhara and Mahāvīra. The last, a Jain scholar who lived in the 9th century in the court of a Rashtrakuta king (in today’s Karnataka), authored the first work of mathematics that was not as part of a text on astronomy. In it, Mahāvīra dealt with finite series, expansions of fractions, permutations and combinations (working out, for the first time, some of the standard formulas in the field), linear equations with two unknowns, quadratic equations, and a remarkably close approximation for the circumference of an ellipse, among other important results. Mathemathics in India 55 Graph showing the high accuracy of Bhāskara I’s rational approximation for the sine function from 0° to 180° (in blue). The sine function (in read) had to be shifted upward by 0.05 to make the two curves distinguishable. (Courtesy: IFIH) Bhāskara II, often known as Bhāskarācārya, lived in the 12th century. His Siddhāntaśiromani (literally, the ‘crest jewel of the siddhāntas’) broke new ground as regards cubic and biquadratic equations. He built upon Brahmagupta’s work on indeterminate equations to produce a still more effective algorithm, the chakravāla (or ‘cyclic method’); with it he showed, for instance, that the smallest integral solutions to 61x2 + 1 = y2 are x = 226153980, y = 1766319049 (interestingly, five centuries later, the French mathematician Fermat offered the same equation as a challenge to some of his contemporaries). Bhāskarācārya also grasped the notion of integration as a limit of finite sums: by slicing a sphere into ever smaller rings, for instance, he was able to calculate its area and volume. He came close to the modern notion of derivative by discussing the notion of instant speed (tātkālika gati) and understood that the derivative of the sine function is proportional to the cosine. The first part of Bhāskarācārya’s Siddhāntaśiromani is a collection of mathematical problems called Līlāvatī, named after 56 Indian Contributions to Science an unknown lady to whom Bhāskara puts problems in an often poetical language. Līlāvatī became so popular with students of mathematics across India that four centuries later, Akbar had it translated into Persian by a court poet. The Kerala School of Mathematics Along with astronomy, mathematics underwent a revival in the Kerala School, which flourished there from the 14th to the 17th century. Its pioneer, Mādhava (c. 1340–1425), laid some of the foundations of calculus by working out power series expansions for the sine and cosine functions (the so- called Newton series), and by spelling out this fundamental expansion of π: This is known as the Gregory–Leibniz series, but ought one day to be named after Mādhava. He went on to propose a more rapidly convergent series for π: which enabled him to calculate π to 11 correct decimals. Nīlakaṇṭha Somayāji (c. 1444–1545) and Jyeṣṭhadeva (c. 1500–1600) built on such results and considerably enriched what might be called the Indian foundations of calculus. The latter, for instance, worked out the binomial expansion: Features of Indian mathematics As elsewhere, mathematics in India arose from practical needs: constructing fire altars according to precise specifications, tracking the motion of planets, predicting eclipses, etc. But India’s approach remained essentially pragmatic: rather than Mathemathics in India 57 developing an axiomatic method such as that of the Greek (famously introduced by Euclid for geometry), it focused on obtaining formulas and algorithms that yielded precise and reliable results. Nevertheless, Indian mathematicians did often provide logically rigorous justifications for their results, especially in the longer texts. Indeed, Bhāskarācārya states that presenting proofs (upapattis) is part of the teaching tradition, and Jyeṣṭhadeva devotes considerable space to them in his Yukti Bhāṣā. The shorter texts, on the other hand, often dispensed with the development of proofs. In the same spirit, the celebrated S. Ramanujan produced many important theorems but did not take time to supply proofs for them, leaving this for others to do! Whether those specificities limited the further growth of Indian mathematics is open to debate. Other factors have been discussed by historians of science, such as historical disruptions of centres and networks of learning (especially in north India), limited royal patronage, or the absence of a conquering impulse (which, in Europe, did fuel the growth of science and technology). Be that as it may, India’s contribution in the field was enormous by any standard. Through the Arabs, many Indian inputs, from the decimal place-value system of numeral notation to some of the foundations of algebra and analysis, travelled on to Europe and provided crucial ingredients to the development of modern mathematics. 7 Metallurgy in India Technology is today defined as applied science, but early humans developed technologies — such as stone-working, agriculture, animal husbandry, pottery, metallurgy, textile manufacture, bead-making, wood-carving, cart-making, boat- making and sailing — with hardly any science to back them up. If we define technology as a human way of altering the surrounding world, we find that the first stone tools in the Indian subcontinent go back more than two million years! Jumping across ages, the ‘neolithic revolution’ of some 10,000 years ago saw the development in agriculture in parts of the Indus and the Ganges valleys, which in turn triggered the need for pots, water management, metal tools, transport, etc. Agriculture apart, metallurgy brought about important changes in human society, as it gave rise to a whole new range of weapons, tools and implements. Some of these had been made in stone earlier, it is true, but the result was coarser as well as heavier. Metal, precious or not, is also a prime material for ornaments, and thus enriches cultural life. Metallurgy may be defined as the extraction, purification, alloying and application of metals. Today, some eighty-six metals are known, but most of them were discovered in the last two centuries. The ‘seven metals of antiquity’, as they are sometimes called, were, more or less in order of discovery: gold, copper, silver, lead, tin, iron and mercury. For over 7,000 years, India has had a high tradition of metallurgical skills; let us see some of its landmarks. Metallurgy in India 59 Metallurgy before and during the Harappan Civilization The first evidence of metal in the Indian subcontinent comes from Mehrgarh in Baluchistan, where a small copper bead was dated to about 6000 BCE; it is however thought to have been native copper, not the smelted metal extracted from ore. The growth of copper metallurgy had to wait for another 1,500 years; that was the time when village communities were developing trade networks and technologies which would allow them, centuries later, to create the Harappan cities. Archaeological excavations have shown that Harappan metal smiths obtained copper ore (either directly or through local communities) from the Aravalli hills, Baluchistan or beyond. They soon discovered that adding tin to copper produced bronze, a metal harder than copper yet easier to cast, and also more resistant to corrosion. Whether deliberately added or already present in the ore, various ‘impurities’ (such as nickel, arsenic or lead) enabled the Harappans to harden bronze further, to the point where bronze chisels could be used to dress stones! The alloying ranges have been found to be 1%–12% in tin, 1%–7% in arsenic, 1%–9% in nickel and 1%–32% in lead. Shaping copper or bronze involved techniques of fabrication such as forging, sinking, raising, cold work, annealing, riveting, lapping and joining. Among the metal artefacts produced by the Harappans, let us mention spearheads, arrowheads, axes, chisels, sickles, blades (for knives as well as razors), needles, hooks, and vessels such as jars, pots and pans, besides objects of toiletry such as bronze mirrors; those were slightly oval, with their face raised, and one side was highly polished. The Harappan craftsmen also invented the true saw, with teeth and the adjoining part of the blade set alternatively from side to side, a type of saw unknown elsewhere until Roman times. Besides, many bronze figurines or humans (the well-known ‘Dancing Girl’, for instance) and animals (rams, deer, bulls...) have been unearthed from Harappan sites. Those figurines were cast by the lost-wax process: the initial model was made of wax, 60 Indian Contributions to Science The ‘Dancing Girl’ (Mohenjo-daro), made by the lost-wax process; a bronze foot and anklet from Mohenjo-daro; and a bronze figurine of a bull (Kalibangan). (Courtesy: ASI) then thickly coated with clay; once fired (which caused the wax to melt away or be ‘lost’), the clay hardened into a mould, into which molten bronze was later poured. Harappans also used gold and silver (as well as their joint alloy, electrum) to produce a wide variety of ornaments such as pendants, bangles, beads, rings or necklace parts, which were usually found hidden away in hoards such as ceramic or bronze pots. While gold was probably panned from the Indus waters, silver was perhaps extracted from galena, or native lead sulphide. After the Harappans During and after the Harappan civilization, a ‘Copper Hoard’ culture of still unclear authorship produced massive quantities of copper tools in central and northern India. Later, in the classical age, copper-bronze smiths supplied countless pieces of art. Let us mention the huge bronze statue of the Buddha Metallurgy in India 61 made between 500 and 700 CE in Sultanganj (Bhagalpur district, Bihar, now at the Birmingham Museum); at 2.3 m high, 1 m wide, and weighing over 500 kg, it was made by the same lost- wax technique that Harappans used three millenniums earlier. So were thousands of statues made later (and up to this day) in Tamil Nadu, such as the beautiful Nataraja statues of the Chola period, among other famous bronzes. Of course, all kinds of bronze objects of daily use have continued to be produced; for instance, highly polished bronze mirrors are still A colossal bronze statue of the made in Kerala today, just as Buddha, Sultanganj: (Courtesy: Wiokipedia) they were in Harappan times. Magnificent Chola bronze statues: Mahālakṣmī and Naṭarāja. (Courtesy: Michel Danino) 62 Indian Contributions to Science Iron Metallurgy While the Indus civilization belonged to the Bronze Age, its successor, the Ganges civilization, which emerged in the first millennium BCE, belonged to the Iron Age. But recent excavations in central parts of the Ganges valley and in the eastern Vindhya hills have shown that iron was produced there possibly as early as in 1800 BCE. Its use appears to have become widespread from about 1000 BCE, and we find in late Vedic texts mentions of a ‘dark metal’ (krṣnāyas), while earliest texts (such as the Rig-Veda) only spoke of ayas, which, it is now accepted, referred to copper or bronze. Whether other parts of India learned iron technology from the Gangetic region or came up with it independently is not easy to figure out. What seems clear, however, is that the beginnings of copper-bronze and iron technologies in India correspond broadly with those in Asia Minor (modern Turkey) and the Caucasus, but were an independent development, not an import. A typical iron-smelting furnace in the first millennium BCE. (Courtesy: National Science Centre, New Delhi) Metallurgy in India 63 Wootz Steel Instead, India was a major innovator in the field, producing two highly advanced types of iron. The first, wootz steel, produced in south India from about 300 BCE, was iron carburized under controlled conditions. Exported from the Deccan all the way to Syria, it was shaped there into ‘Damascus swords’ renowned for their sharpness and toughness. But it is likely that the term ‘Damascus’ derived not from Syria’s capital city, but from the ‘damask’ or wavy pattern characteristic of the surface of those swords. In any case, this Indian steel was called ‘the wonder material of the Orient’. A Roman historian, Quintius Curtius, recorded that among the gifts which Alexander the Great received from Porus of Taxila (in 326 BCE), there was some two-and-a-half tons of wootz steel — it was evidently more highly prized than gold or jewels! Later, the Arabs fashioned it into swords and other weapons, and during the Crusades, Europeans were overawed by the superior Damascus swords. It remained a favoured metal for weapons through the Moghul era, when wootz swords, knives A typical sword made of wootz steel (about 18th century); the hilt is of iron and coated with a thick layer of gold. (Courtesy: R. Balasubramaniam

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