Friday, September 30, 2011

Early and Medieval Hindus’ Contribution to Science and Technology




The contribution of Hindu India to the field of science and technology during ancient and medieval ages is no less significant than its contribution to the field of spiritual wisdom. The word 'rishi' is generally translated as 'sage'—just signifies a man of knowledge, in any field for that matter, since it is derived from the Samskrit root 'rish' to know. Thus if Vaasishta and Vyaasa were rishis in the field of spiritual wisdom, Dhanvantari, Varaahamihira, and Bhaaskara were rishis in the fields of medicine, astronomy and mathematics.

India's work in science is both very old and young as an independent and secular pursuit, old as subsidiary interest of her vedantic and priestly pursuit and young in its modern pursuit. Religion being the core of Hindu life, those sciences were cultivated first that contributed to religion.


Surya siddhanta, considered as a revealed work, is the earliest of the available works on Hindu astronomy. Other great treatises in astrology are known as Sathya Samhita and Saptarishi Naadi, which consists of twelve books in Tamil. Bhrigu Samhita consists of four books and about ten thousand verses. The Hindu god of astrology is Lord Subrhamanya, the son of Shiva. Most of the valuable knowledge is lost due to the practice of utmost secrecy by the learned sages and today's astrology is only a skeleton, according to some. As per legends, sage Bhrigu wrote astrological charts giving the horoscope of every person ever born or to be born in the world. The writings of Bhrigu are popularly known as Bhrigu Samhita and are available from few astrologers in India.

Astrology grew out of the worship of heavenly bodies, and their observations of their movements aimed to fix the calendar of festival and sacrificial days. As in the Middle Ages, the scientists of India were her priests or gurus.

At a time when vedic sacrifices were all important, there was a great need to determine the correct times for performing them. This gave rise to a new branch of knowledge called 'Jyotisha' or 'Jyautisha' which was deemed as a Vedanga, a subsidiary science of Vedas. This was the origin of Hindu astronomy. It dates back to 1400 B.C. Astronomy was an incidental offspring of astrology. The earliest astronomical treatise, Suryasiddhanta (ca 425 B.C.) was thoroughly revised by Varaahamihira (6th century A.D.)

The works attributed to him are: Brihajjaataka, Laghujaataka, Panchasiddhaantika and Brihatsamhita. Varaahamihira's compendium was significantly entitled complete system of Natural Astrology, who drew considerable support from Greeks. The greatest Hindu astronomer Aryabhatta discussed in verse such poetic subjects that covered quadratic equations, sine and the value of pi ( ); he explained eclipses, solstices and equinoxes, announced spheroid of the earth and its diurnal revolution on its axis and wrote, in daring anticipation of Renaissance Science: "the sphere of the stars is stationary, and the earth, by its revolution produces the daily rising and setting of planets and stars".

His most famous successor Brahmagupta, systematized astronomical knowledge of India, but obstructed its development by rejecting Aryabhatta's theory of the revolution of the earth. These men and their followers adopted to Hindu usage the Babylonian division of the skies into zodiacal constellations; they made a calendar of twelve months, each of thirty days, each of thirty hours inserting an intercalary month every five years; they calculated with remarkable accuracy the diameter of the moon and the sun, the position of the poles, and the position of the major stars. They expounded the theory, though not the law, of gravity, when they wrote in Siddhanta: "the earth, owing to its force of gravity draws all things to itself". The vedic sages were fully aware of the following astronomical facts and phenomena:
  1. The earth is round, rotates on its own axis and also around the sun.
  2. Sunlight has seven colors, allegorically described as seven horses.
  3. The twelve signs of the zodiac.
  4. There are 366 days in a year.
  5. The number of days per month is 29 11/16 or 29.762 days.

To make these complex calculations, the Hindus developed a system of mathematics, superior in everything to that of Greeks. Among the most vital parts of Western Oriental heritage are the "Arabic" numbers and the decimal system, both of which came to the West through the Arabs from India. The miscalled Arabic numbers are found on the rock edicts of Ashoka (256 B.C.), a thousand years before their occurrence in Arabic literature.

The decimal system was known to Aryabhatta and Brahmagupta long before its appearance in the writings of the Arabs and Syrians; adopted by China by Buddhist missionaries; Muhammad Ibn Musa-al-Khwarzami, the greatest mathematician of his age (ca 850A.D.) seems to have introduced it into Baghdad. The oldest use of the 'zero' in Asia or Europe is in Arabic document dated 873 A.D., three years sooner than its first appearance in India. But by general consent Arabs borrowed this from India and the most modest and most valuable of all numerals is one of the subtle gifts of India to mankind.

Algebra was developed in apparent independence by both Hindus and the Greeks, but the Western adoption of its Arabic name, al-jabr meaning adjustment, indicates that it came to Western Europe from the Arabs—i.e. from India. The great Hindu leaders in the field as in astronomy were Aryabhatta, Brahmagupta and Bhaskara. The last (1114 A.D.) appears to have invented the radical sign and many algebraic symbols. Bhaskara is the author of Beejaganitha, a work on mathematics, the Siddhanta Siromani on astronomy and Lilavati. In his computation of the size of the hydrogen atom, he used differential calculus. Valuable information regarding Hindu mathematics is found in Bakshali manuscript discovered in India in 1881. These men created the conception of negative quantity without which algebra would have been impossible; they formulated rules for finding permutations and combinations, they found the square root of 2, and solved, in 8th century A.D., indeterminate equations of the second degree that were unknown to Europe until the days of Euler, a thousand years later. They expressed their science in the poetic form, and gave mathematical problems a grace characteristic of India's Golden Age. Algebra was known as "kuttaganita" first. The term "beejaganita" used in the modern period was given by one Prithhoodaka Swami (860A.D.)

The construction of sacrificial altars and the arrangement for laying the bricks for them posed a problem to the vedic Aryans. While attempting to solve the problem, they discovered geometrical methods of algebra. The Sulbasaastras of Aapasthamba (400B.C.), Baudhaayana(600B.C.), Kaatyaayana(400A.D.) and others gave the solutions of linear, quadratic, simultaneous or even indeterminate equations. Signs of numbers counting up to very huge quantities like 'Praraardha'(10 raised to the power of 31), the decimal and the duo-decimal systems, the concept of zero and infinity, surds and indeterminate analysis were all familiar subjects to the ancient and medieval Hindus. In the Sthaanaangasutra (100 B.C.) simple, quadratic and cubic equations are given..

Aryabhatta, probably influenced by Greeks, found the area of a triangle, a trapezium and a circle and calculated the value of pi at 3.1416—a figure not equaled in accuracy until the days of Purbach (1423 A.D.) in Europe. Trigonometry evolved as an integral part of astronomy. Bhaskara crudely anticipated the differential calculus; Aryabhatta drew up a table of sine and the Suryasiddhanta provided a system of trigonometry more advanced than anything known to Greeks. The functions of sine and cosine were called 'jyaa' and 'kojya'. A number of elementary formulae—such as sine (90 – 0) = cos 0, as also trigonometry series had also been developed.

Coming to geometry as such, it had its origin in the building of vedic sacrificial altrars. The so called Pythagoras Theorem had already been enunciated by Baudhaayana (600B.C.). Problems like the area of quadrilateral or the diagonals of cyclic quadrilateral have been successfully solved by Brahmagupta in his Brahmasphuta Siddhanta. Rudimentary ideas of integral calculus and differential calculus are found in the works of Brahmagupta and Bhaskara II (A.D. 1150).

Kanada, founder of the Vaisheshika philosophy held that the world was composed of atoms as many in kind as the various elements. The Jains nearly approximated to Democritus by teaching that all atoms were of the same kind, producing different modes of combinations. Kanada believed light and heat to be varieties of the same substance. Udayana taught that all heat came from the Sun and Vaachaspati, like Newton, interpreted light as component of minute particles emitted by substances striking the eye. Musical notes and intervals were analyzed and mathematically calculated in the Hindu treatise on music, Sangeeta Ratnaakara of Saarangadeva. The Pythagorian Law was formulated by which the number of vibrations as the length of the string between the point of attachment and the point of touch in the stringed instrument. There is some evidence that the Hindu mariners of the first century A.D. used a compass made by an iron fish floating in a vessel and pointing north.

Chemistry developed from two sources—medicine and industry. Mention has been made about the chemical excellence of cast iron, in ancient India, and about the high industrial development (1210—47), of Gupta period, when India was looked to, even by Imperial Rome, as the most skilled of nations in such chemical industries as dyeing, tanning, soap making, glass and cement. As early as 2nd century B.C., Nagarjuna devoted an entire volume to mercury. By the 6th century, Hindus were far ahead of Europe in Industrial Chemistry; they were masters of calcinations, distillation, sublimation, steaming, fixation, the production of light without heat, the mixing of anesthetic and soporific (hypnotic) powders and precipitation of metallic salts, compounds and alloys.

The tempering of steel was brought to perfection in ancient India unknown in Europe till modern times. King Porus is said to have selected, as a special valuable gift to Alexander, not gold or silver, but thirty pounds of steel. The Moslems took much of the Hindu chemical science to the Near East and Europe; the secret of "Damascus" blades for example, was taken by the Arabs from the Persians and by the Persians from India.

The Arthasastra of Kautilya (300 B.C.) and the Samhita of Charaka (300 A.D.) and Sushruta (500 A.D.) contain a wealth of information regarding chemistry also along with that of medicine and metallurgy. Procedures for extracting and purifying metals like lead, copper, silver and gold, preparation of various kinds of fermented liquors and anhydrous alcohol by distillation, formation of sulfides, preparation and properties of alkali carbonates and caustic alkalis as well as neutralization of the acid by an alkali—these and many more things have been described in these works. An elaborate discussion about the chemistry of digestion of food in human beings is found in the Charaka Samhita and Ashtanga Hridaya Samhita of Vagbhatta II (A.D. 650)

The process of melting, refining and coloring of glass was known even as early as the 6th century B.C. as borne out by the discovery of earliest specimen of glass at the Bhirmound in Takshasila or Taxila. The art of making painted, decorated and glazed pottery was current by 300 B.C. So also was the use of indigo, shellac, turmeric, resin and red ochre. Preparation of elixir of life and conversion of base metals to gold were the two-fold objectives of alchemists. In medieval India, Tantric cults were interested in alchemy.

The Rasaarnava (12th century), the Dhaatuvaada (8th century), the Rasendrachoodaamani were some of the treatises composed during the middle ages which dealt with subjects like purification of mercury by distillation, making cuprous sulfide and sulfuric acid.

Mining for precious metals and precious stones have been described by Megasthanes, as well known to Hindus.

The archaeological excavations at Baragunda (Singbaum), Mosabani (Singbaum), Agnigundala (A.P.) and Wynad (Kerala) have revealed extensive, abandoned copper and gold mines.

Vedic Aryans were familiar with the use of metals such as gold, silver, copper, lead, tin, bronze and iron. This presupposes that they had a fair knowledge of mining and metallurgy.

Much of the gold used in the Persian Empire in the 5th century B.C. came from India long before its known appearance in Europe. Vikramaditya erected at Delhi (ca 380 A.D.), an iron pillar that remains untarnished which is considered as a marvel even today. It is 24 feet in height and 16 inches in diameter, weighing 6 tons. The quality of metal or manner of treatment which has preserved it from rust or decay is still a mystery to modern metallurgical science. Before European invasion the smelting of iron in small charcoal furnaces was one of the major industries in India. The copper image of Buddha found at Sultanganj (Bihar) is another marvel. It is cast in pure copper. It is 7.5 ft in height and weighs 1 ton. It belongs to the 5th century A.D. Huen Tsang (A.D.600—664) refers to a colossal 24 meters (80 ft) copper statue of Buddha established by King Poornavarman near the Nalanda University in Bihar.

Silver and gold jewelry with granulation and filigree work made on copper and bronze moulds have been found at Taxila site (circa 3rd century B.C.)

Specimens of implements and a large variety of weapons discovered at Tirunelveli (TN) have been assigned to the period of 4th century B.C. Radio-carbon dating of some of the samples of iron objects obtained in the archaeological excavations in parts of North India and Delhi varies from 1025 to 537 B.C.


The medieval Arabs took over the art of making cloth from cotton from India and their word 'Quattan' gave English the word cotton. The name of Muslin was originally applied to fine cotton weaves made in Mosul from Indian models. Calico came from Calicut in Kerala. Europe looked upon Hindus as experts in almost every line of manufacture—wood work, metal work, glass blowing, gun powder, fire works, cement etc. China imported eye glasses from India in 1260 A.D.

A fairly good knowledge of botanical sciences existed in India even in the Vedic period. The Vedic Aryans were aware of what is now termed as 'photo-synthesis'. The Arthasastra of Kautilya (300 B.C.) refers to gulmavriksha ayurveda (science of bushy plants and trees). A lot of information regarding soils, seed selection, sowing, germination, grafting and cutting, rotation of crops, plant classification and so on is found in some puranas like Agnipurana (800 A.D.). An account of the different parts of a plant body like the roots, and shoots, stem and branches, leaves, flowers and fruits are found in the Rigveda, Atharvaveda, Taittareeya Samhita, Vaajasaneyi Samhita. Indian literature of the post-vedic period (600B.C. to 600 A.D.) bears ample evidence to the knowledge of morphology, physiology, ecology and taxonomy of plants. The famous Samskrit lexicon Amarakosha of Amarasimha (A.D. 400) has enumerated more than three hundred species of plants. Medicinal herbs and plants naturally received great attention due to their being closely associated with Ayurveda, the science of medicine and surgery. All the methods of propagation now known to us were a common knowledge. To mention a few: propagation of seeds, roots, cuttings and grafting. Treatise such as Arthasastra, Brihat Samhita and Manu Samhita refer to all of them.

Plants have been regarded, even from the Vedic times, as living organisms. In the naming of the plants, a rational and scientific procedure was followed, which is in no way inferior to modern methods.

During the medieval period botanical research—including possibilities of developing new species—for further fillip, is evidenced in the Sarangadhara Paddhati of Saarangadhara (14th century).

Being agro-centered society, the Hindus depended heavily on cows, bulls and other animals of the bovine species. The rulers of the land needed horses and elephants for their armed forces. Hence these categories attracted much attention of the society and a veterinary science centered round them developed in course of time. They are: Gavaayurveda, Asvaayurveda and Hastyaayurveda (pertaining to the bovine species) attributed to the sage Gotama, were the standard works current until the middle ages. Apart from diseases and their treatment, the texts contained information about diet, breeding, calving, lactation and milk.

The principle work on Asvaayurveda is the Saalihotra Samhita of uncertain date. Extracts from it are found in Agnipurana. The Saalihotra Samuchchaya of Kalhana (12th century A.D.) is believed to be a redaction Samhita. It is a voluminous work throwing light on different aspects of the horses like anatomy, physiological and pathological conditions relating to breed, sex, age and so on.

The Paalakaapya Samhita attributed to to Paalakaapya, is an exhaustive treatise on Hastyaayurveda. It is a work in the form of question and answers between the sage and his disciple Romapada. It deals with anatomy, physiology, pathology, major and minor diseases with medical and surgical treatments, drugs and diet. Another work on the same subject is the Maatangleela of Nilakhantaacharya. The date of both these works is unknown. It is interesting to note that there was a regular veterinary hospital in the campus of Nalanda University.

The Arthasastra of Kautilya (300 B.C.) has several references to fish and fisheries, to rearing animals such as cows, buffaloes, goat, sheep, horses and elephants.

Foreign travelers like Megasthanes (300 B.C.) and Strab (54-24 B.C.) have declared that 1) the Hindus of India attained longevity due to good food, pure air and good habits. 2) the Hindu physicians and surgeons were greater experts in their field than their contemporary Greeks 3) Even Alexander preferred to employ the Hindu physicians to look after his army men 4) Ashoka had established hospitals not only for human beings but also for animals.

It is very interesting to note that a very strict code of conduct has been laid down in their medical works for the doctors. They are: 1) A doctor should treat his patients to the best of his ability since they trust him for their lives 2) A doctor should refuse to treat morally deprived persons since they are a scourge to the society 3) A doctor should not take up terminal cases where he is sure that death is imminent, as also refuse to treat persons suffering from incurable diseases. 4) Once he agrees to treat a patient, he should provide him with proper medical and nursing facilities and also treat him kindly; 5) a doctor should never attend to a woman patient in the absence of her husband and guardians; 6) all professional information should be kept strictly confidential. Many of these medical treatises were translated into Arabic language and their practices introduced into Europe by the Arab physicians.

Anatomy and physiology, like some aspects of chemistry, were products of Hindu medicine. As far back as the sixth century B.C., Hindu physicians described ligaments, sutures, lymphatic, nerve plexus, fascia, adipose and vascular tissues, mucous and synovial membranes and many more muscles than modern cadaver is able to show. Doctors of pre-Christ era share Aristotle's mistaken conception of the heart as the seat and organ of consciousness and supposed that the nerves ascended to and from the heart. But they understood remarkably well the process of digestion—the different functions of the gastric juices, the conversion of chime into chyle, and this into blood. Anticipating Weissmann by 2400 years, Atreya (ca 500B.C.) held that parented seed is independent of the parent's body, and contains in itself, in miniature, the whole parental organism. Examination of virility was recommended as prerequisite for marriage in men; and the code of Manu warned against marrying mates affected with tuberculosis, epilepsy, leprosy, chronic dyspepsia or loquacity. Birth control in the latest theological fashion was suggested by the Hindu schools of 500 B.C. in the theory that during twelve days of menstrual cycle conceiving is impossible. Fetal development was described with considerable accuracy; it was noted that sex of the fetus remains for a time undetermined, and it was claimed that in some cases the sex of the embryo could be influenced by food or drugs.

Though the elements of Ayurveda are found even in Rigveda, it is only in Atharvaveda, the record of Hindu medicines begin; more embedded in a mass of magic and incantations, is a list of diseases with their symptoms. It is said that the original text of Ayurveda, composed by Lord Brahma himself, contained 100,000 verses and was composed long before the creation of the beings (Sushmita Samhita 1:1-5). Now the Atharvaveda contains only 6000 verses. Some call Ayurveda as the fifth Veda. Healers in Ayurveda are Dhanvanatari, Brihaspati and Indra. The prominent physicians of Ayurveda were Charaka (80-180 A.D.), Sushruta (around 350 A.D.), Vagbhatta (610-850 A.D.) and Madhva (around 1370 A.D.). Medicine arose as an adjunct of magic; the healer studied and used earthly means of cure to help his spiritual formula; later he relied more and more upon such secular methods continuing the magic spell, like bedside manner as psychological aid. Appended to Atharvaveda is Ayurveda (science of longevity). In this oldest system of Hindu medicine, illness is attributed to disorder in one of the four humors—air, water, phlegm and blood and treatment is recommended with herbs and charms. Many of its diagnoses and cures are still used in India, with a success that is sometimes the envy of Western physicians. The Rigveda names over a thousand such herbs and advocates water as the best cure for most diseases. Even in Vedic times physicians and surgeons were differentiated into magic doctors and were living in houses surrounded by gardens in which they cultivated medicinal plants. The great names of Hindu medicines are those of Sushruta and Charaka. Sushruta, professor of medicine in the University of Benares wrote down in Samskrit, system of diagnosis and therapy whose elements descended to him from his teacher Dhanvantari. His book dealt at length with surgery, obstetrics, diet, bathing, drugs, infant feeding, hygiene and medical education.

Charaka composed a Samhita (or encyclopedia) of medicine which is still used in Ayurveda, and gave his followers an almost Hyppocratic (followers of Greek physician 400 B.C.) conception of their calling: "Not for self, not for the fulfillment of any earthly desire of gain, but solely for the good of suffering humanity should you treat your patient, and so excel all".

Only less illustrious than these are Vagbhatta II (625 A.D.) who prepared a medical compendium in prose and verse, and Bhava Misra (1550 A.D.), whose voluminous work in analog physiology and medicine, mentioned a hundred years before Harvey the circulation of blood and prescribed mercury for that novel disease syphilis, which had recently been brought in by the Portuguese as a part of Europe's heritage to India.

The standard texts generally deal with Ashtangas or eight subjects. They are: Kaayachikitsa (therapeutics), Salyatantra (major surgery), Saalaakyatantra(minor surgery including ENT), Bhutavidya (psychiatry), Kumaarabhrityatantra (pediatrics), Agadatantra (toxicology), Rasaayanatantra(geriatrics) and Vaajeekaranatantra(virilification).

Some additional information is given in these texts as also the Arthasastra of Kautilya: details of the bones and naalas or naadees (blood vessels and nerves) in the human body; duties of the toxicologists and nurses; rules and regulations for the surgeons; certain modes and methods of treatment like the application of oils and ointments; bandaging techniques; surgical instruments and how to use them and so on. Susshruta described many surgical operations—cataract, hernia, lithotomic, caesarian section etc. and 121 surgical instruments including lancets, sounds, forceps, catheters and rectal and vaginal speculums. Despite brahminical prohibitions, he advocated the dissection of dead bodies as indispensable in the training of surgeons. He was the first to graft upon torn ear portions of skin taken from another part of the body. The surgical reconstruction of the nose descended into modern medicine from him and his Hindu successors. "The ancient Hindus" says Garrisons, "performed almost every major operations except legation of arteries. Limbs were amputated, abdominal sections were performed, fractures were set, hemorrhoids and fistula were removed. Sushruta laid down elaborate rules for preparing an operation, and his suggestions that the wound be sterilized by fumigation is one of the earliest known effects at antiseptic surgery. Both Sushruta and Charaka mention the use of medicinal liquors to produce insensitivity to pain. In 927 A.D. surgeons trepanned the skull of a Hindu king, and made him insensitive to the operation by administering the drug called Sammohini.

For the detection of the 1120 diseases that he enumerated, Sushruta recommended diagnosis by inspection, palpitation and auscultation. Taking the pulse was described in a treatise dating 1300 A.D. Urinalysis was a favorite method of diagnosis; Tibetean physicians were reputed, able to cure any patient without having seen anything more than his water. In the time of Yuan Chwang, Hindu medical treatment began with a seven day fast; in this interval the patient often recovered; if the illness continued drugs were employed. Even then drugs were used sparingly; reliance was placed largely upon diet, baths, enemas, inhalations and blood letting with leeches or cups. Hindu physicians were especially skilled in concocting antidotes for poisons; they still excel European physicians in curing snake bites. Vaccination, unknown in Europe before 18th century was known in India as early as 550 A.D.; if we may judge from a text book attributed to Dhanvantari, one of the earliest Hindu physicians: "take the fluid of the pock on the udder of the cow…; upon the point of a lancer and lance with it the arms between the shoulders and elbows until the blood appears; by mixing of the fluid with the blood, the fever of the small-pox will be produced.

Hypnotism, as a therapy seems to have originated among the Hindus, who often took their sick to temples to be cured by hypnotic suggestion or 'temple sleep' as in Egypt and Greece. The Englishmen who introduced hypnotherapy into England—Braid, Esdaile and Ellison undoubtedly got their ideas and some of their experiences from their contacts in India.

The ancient Hindus practiced plastic surgery before 1000 A.D. They worked with steel surgical instruments and used alcohol to dull the senses. One reason for that development of this skill was the common punishment for adultery—cutting off the nose. Surgeons repaired the damage with tissues cut from either the cheek or forehead rebuilding the nose around the stump. During the operation the patient breathed through the reeds placed in the nasal openings. World War I, with its attendant disfiguring injuries was largely responsible for making plastic surgery more widely available in Western medicine.

Sushruta lived in sixth century BC He originated plastic surgery and the operation of the cataract in the eye. His technique as laid down in his texts was studied by the West and the science of Plastic surgery was evo0lved out of it. Sushruta knew how to repair bad or desisted noses and it is said that he fixed once torn ear and also grafted portions of skin from other parts of the body. He knew how to remove stones from the bladder. Despite religious objections, he advocated the cutting up or dissection of dead bodies for teaching of medical trainees.


Modern European physicians believe that caste separateness was prescribed because of the Brahmin belief in invisible agents transmitting diseases. The caste system had the eugenic value (relating to the production of good off-spring--keeping the presumably finer strains from dilution and disappearance through indiscriminate mixture. It established certain habits of diet and cleanliness as rule of honor which all might observe and emulate. Eugenics, a science that deals with improvement (as by control of human mating) of hereditary qualities of a race or breed, probably was well understood by the sages, as cited in Puranas. Many of the laws of sanitation enjoined by Sushruta and Manu seem to take for granted what the moderns, who love New Worlds for old things, call the germ theory of diseases.

The great picture of Indian medicine is one of rapid development in the Vedic and Buddhist periods followed by centuries of slow and cautious improvement. How much Atreya, Dhanvantari, and Sushruta owed to Greece, and how much Greece owed to them, we do not know? In the time of Alexander, says Garrison, Hindu physicians and surgeons enjoyed a well deserved reputation for superior knowledge and skills and even Ariostotle is believed by some to have been indebted to them. So too, with Persians and Arabs. It is difficult to say how much Indian medicine owed to the physicians of Baghdad, and through them to the heritage of the Babylonian medicine of the Near East; on the one hand certain remedies like opium and mercury, and some modes of diagnosis like feeling the pulse, appear to have entered India from Persia, on the other hand we find Persians and Arabs translating into their languages in eighth century A.D., the thousands year old Compendium of Sushruta and Charaka.

The great Caliph Haroun-al-Rashid accepted pre-eminence of Indian medicine and scholarship and imported Hindu physicians to organize hospitals and schools in Baghdad. Lord Ampthill concludes that medieval and modern Europe owes its system of medicine directly to the Arabs and through them to India. Probably the noblest and most uncertain of the sciences had an approximately equal antiquity and developed in contemporary contact and mutual influence, in Sumaria Egypt and India.

The sages of India never considered religion and science as conflicting areas of knowledge. Einstein once said: "religion without science is lame and science without religion is blind". To the Hindu sages both were equally important, one being the quest for the     Truth within and the other, without. They were actually two facets of the same Vidya or science. That is why they were called Para-vidya (higher knowledge) and Apara-vidya (lower knowledge). One thing which was basic to all these rishis was that their knowledge was always meant to be used within the perimeters of Dharma, for the Universal good of mankind. They were blessed with yogic powers, superior intelligence and high degree of concentration. The discovery by these sages that Brhman, the basis of external Universe and, Aatman the basis of internal world, are ultimately one and pure Consciousness has obliterated the walls between these two fields of knowledge. It is no wonder therefore there was a rapid development of science and technology in India during the Vedic and Medieval periods, which somehow lost its pace due to gradual changes in people's outlook and outside pressures and influence.



It is amazing how much Western science has taught us. Today, for example, kids in grammar school learn that the sun is 93 million miles from the earth and that the speed of light is 186,000 miles per second. Yoga may teach us about our Higher Self, but it can't supply this kind of information about physics or astronomy.
Or can it? Professor Subhash Kak of Louisiana State University recently called my attention to a remarkable statement by Sayana, a fourteenth century Indian scholar. In his commentary on a hymn in the Rig Veda, the oldest and perhaps most mystical text ever composed in India, Sayana has this to say: "With deep respect, I bow to the sun, who travels 2,202 yojanas in half a nimesha."
A yojana is about nine American miles; a nimesha is 16/75 of a second. Mathematically challenged readers, get out your calculators! 2,202 yojanas x 9 miles x 75/8 nimeshas = 185,794 m. p. s.
Basically, Sayana is saying that sunlight travels at 186,000 miles per second! How could a Vedic scholar who died in 1387 A. D. have known the correct figure for the speed of light? If this was just a wild guess it's the most amazing coincidence in the history of science!
The yoga tradition is full of such coincidences. Take for instance the mala many yoga students wear around their neck. Since these rosaries are used to keep track of the number of mantras a person is repeating, students often ask why they have 108 beads instead of 100. Part of the reason is that the mala represent the ecliptic, the path of the sun and moon across the sky. Yogis divide the ecliptic into 27 equal sections called nakshatras, and each of these into four equal sectors called paadas, or "steps," marking the 108 steps that the sun and moon take through heaven.
 Each is associated with a particular blessing force, with which you align yourself as you turn the beads. Traditionally, yoga students stop at the 109th "guru bead," flip the mala around in their hand, and continue reciting their mantra as they move backward through the beads. The guru bead represents the summer and winter solstices, when the sun appears to stop in its course and reverse directions. In the yoga tradition we learn that we're deeply interconnected with all of nature. Using a mala is a symbolic way of connecting ourselves with the cosmic cycles governing our universe.
But Professor Kak points out yet another coincidence: The distance between the earth and the sun is approximately 108 times the sun's diameter. The diameter of the sun is about 108 times the earth's diameter. And the distance between the earth and the moon is 108 times the moon's diameter.

Could this be the reason the ancient sages considered 108 such a sacred number? If the microcosm (us) mirrors the macrocosm (the solar system), then maybe you could say there are 108 steps between our ordinary human awareness and the divine light at the center of our being. Each time we chant another mantra as our mala beads slip through our fingers, we are taking another step toward our own inner sun.
 As we read through ancient Indian texts, we find so much the sages of antiquity could not possibly have known-but did. While our European and Middle Eastern ancestors claimed that the universe was created about 6,000 years ago, the yogis have always maintained that our present cosmos is billions of years old, and that it's just one of many such universes which have arisen and dissolved in the vastness of eternity.
 In fact the Puranas, encyclopedias of yogic lore thousands of years old, describe the birth of our solar system out of a "milk ocean," the Milky Way. Through the will of the Creator, they tell us, a vortex shaped like a lotus arose from the navel of eternity. It was called Hiranya Garbha, the shining womb. It gradually coalesced into our world, but will perish some day billions of years hence when the sun expands to many times it present size, swallowing all life on earth. In the end, the Puranas say, the ashes of the earth will be blown into space by the cosmic wind. Today we known this is a scientifically accurate, if poetic, description of the fate of our planet.
The Surya Siddhanta is the oldest surviving astronomical text in the Indian tradition. Some Western scholars date it to perhaps the fifth or sixth centuries A. D., though the text itself claims to represent a tradition much, much older. It explains that the earth is shaped like a ball, and states that at the very opposite side of the planet from India is a great city where the sun is rising at the same time it sets in India. In this city, the Surya Siddhanta claims, lives a race of siddhas, or advanced spiritual adepts. If you trace the globe of the earth around to the exact opposite side of India, you'll find Mexico. Is it possible that the ancient Indians were well aware of the great sages/astronomers of Central America many centuries before Columbus discovered America?- the Mayans or Inca-s!!!
Knowing the unknowable: To us today it seems impossible that the speed of light or the fate of our solar system could be determined without advanced astronomical instruments--as Sanjee argues!!
How could the writers of old Sanskrit texts have known the unknowable? In searching for an explanation we first need to understand that these ancient scientists were not just intellectuals, they were practicing yogis. The very first lines of the Surya Siddhanta, for of the Golden Age a great astronomer named Maya desired to learn the secrets of the heavens, so he first performed rigorous yogic practices. Then the answers to his questions appeared in his mind in an intuitive flash.
Does this sound unlikely? Yoga Sutra 3:26-28 states that through, samyama (concentration, meditation, and unbroken mental absorption) on the sun, moon, and pole star, we can gain knowledge of the planets and stars. Sutra 3:33 clarifies, saying: "Through keenly developed intuition, everything can be known." Highly developed intuition is called pratibha in yoga. It is accessible only to those who have completely stilled their mind, focusing their attention on one object with laser-like intensity. Those who have limited their mind are no longer limited to the fragments of knowledge supplied by the five senses. All knowledge becomes accessible to them.
"There are [those] who would say that consciousness, acting on itself, can find universal knowledge," Professor Kak admits. "In fact this is the traditional Indian view."
Perhaps the ancient sages didn't need advanced astronomical instruments. After all, they had yoga.


Distance between Sun and Earth is Mentioned in Hanuman Chalisa
Posted by The Editor | Sep 13, 2015 |  IndiaDivine.Org

According to modern astronomy and science, we know that the earth’s orbit around the sun is not a circle and is slightly elliptical. Therefore, the distance between the earth and the sun varies throughout the year. At its nearest point on the ellipse that is the earth’s orbit around the sun, the earth is 91,445,000 miles (147,166,462 kms) from the sun. This point in the earth’s orbit is known as Periapsis (perihelion) and it occurs around January 3.
The earth is farthest away from the sun around July 3 when it is 94,555,000 miles (152,171,522 km) from the sun. This point in the earth’s orbit is called Apoapsis (aphelion). The average distance from the earth to the sun is 92,955,807 miles (149,597,870.691 km).
According to records, for the first time in 1672, Jean Richer and Giovanni Domenico Cassini measured the distance between the Earth and Sun as 22,000 times of Earth Radii. (Earth’s Radius is 6,371 Km) i.e. 22,000 * 6,371 km = 140,162,000 km  (140 million km).

Two lines of the Hindu prayer Hanuman Chalisa compute this distance with great simplicity.
जुग सहस्त्र योजन पर भानु, लील्यो ताहिमधुर फल जानू
This means that the Sun (भानु) is at a distance of yuga sahastra yojanas (जुग सहस्त्र योजन – Distance Unit in Sanskrit/Hindi).
According to the following conversion practices that are in use as per Hindu Vedic literature:
1 yuga = 12000 celestial years
1 sahasra = 1000
1 yojana = 8 Miles
yuga x sahasra x yojana = para bhanu
12,000 x 1000 x 8 miles = 96,000,000 miles
1 mile = 1.6kms
96,000,000 x 1.6kms = 153,600,000 km to the Sun.
The earth moves in an elliptical orbit around the sun, so there will be slight variation depending on the season.
Hanuman challisa was written by Goswami Tulasidas (born 15th century) in Awadhi language who belongs to 15th century, which means the distance between the Sun and earth had been calculated much more accurately than the 17th century scientists even before 2 centuries.
The question here is how Tulsidas calculated this distance or how he is able to know about this distance. We also have to observe that the people of that age had more knowledge, capabilities and much more advanced technology that is beyond the imagination of our present day technologies.
History is not presented to us in the way it should be. There are still many elements and precious jewels of information that are being kept hidden from us. The ocean of history is before you, dive in and dig the jewels out. The gleaming beam of knowledge from these jewels will not only enrich our country but will also keep bestowing direction to our future generations.
We hope that this post will help you to understand the significance of our ancient principles, technology and culture.

Sulbasutras: Indian Texts on Sacred Geometry
Posted by The Editor | Feb 19, 2012 |  

The Sulbasutras deal with geometrical constructions, a large majority of them for the purpose of carrying out Vedic rituals at precisely constructed altars and similar such ends, that are popularly believed to date to the millennium before Christ or the end of the Vedic age. Of these, Baudhayana’s Sulbasutra is believed to date to the 8th century B.C. Later, other authors including Apastamba, Manava, Katyayana,Satyasadha Hiranyakesin, Vadhula, Varaha and Kathaka composed sulbasutras as well, although the chronological order in which these texts were composed remains unknown as yet.
The first five of the sulbasutras is found available in text form while the manuscripts of the others are known to exist. Still later, the commentaries of Kapardi, Karavinda, Sundararaja and Dwarkanath appeared. In more recent times there have been commentaries written by Thibault and Van Geldner in the second half of the 19th century A.D., followed by S. N. Sen and the last by A.K. Bag in 1983.
Baudhayana’s work and his successors
The Baudhayana Sulbasutram (BSS) is possibly the most important sulbasutra text since it contains the principles of prescribed geometry for the Vedic altar space. Baudhayana, after dwelling upon the basic geometrical construction concepts prevalent during his and earlier times in the first set of sutra, described the Vedic altar space in general and then the 14 uttaravedi forms. His descriptions of the uttaravedis reveal a remarkable approach to geometry and the text serves as a model for technical accuracy and brevity. The order present in the geometrical analysis as well as in the flow of the text, its subject matter, reveal great clarity of thinking in the author’s mind and set the text apart from its later counterparts.
The later sulbasutras either dealt with matters mentioned in Baudhayana’s work and developed it further, or discussed issues that were omitted from this earlier work. Some of these works may be considered supplementary material. Katyayana’s text described how the construction of the uttaravedis may range from a size of 7.5to 101 purusam square in a clear narrative style. Similarly, Manava documented the examples of 8.5 square purusam uttaravedis, something that neither Baudhayana nor Katyayana had done. Manava further stated a new approach to the use of the purusam measure and a new unit of measure called pancangi. While a continuity of subject-matter may be observed in Katyayanaand Manava’s work, Apastamba’s output did not conform to the trend set by Baudhayana. No clear enhancement or elucidation of former works on geometry was discernible in his work. He described two forms of brick layout for the pithan syenaciti and new kanka and alaja citis, and his work on this proved to be very popular.
Recent Interest in the Sulbasutras
The cryptic style of the sulbasutra texts was essentially suited to the Vedic ritualists and in the wake of a break with traditional rituals and practices after the Vedic period, the texts could have lost their popular relevance. In some cases, this seems to be exactly what happened- a disconnect between the content of the text and the purposes to which it no longer was applicable. This made it very difficult to retrieve the sulbasutras completely at a later date when scholastic interest in them was reawakened. Therefore, it is doubtful how far the earlier mentioned commentaries are capable of revealing the real geometrical contents of the sulbasutra in all their glory.
The work done on the sulbasutras since the 19th century A.D. has, however, been followed with interest in recent times. It is clear that the major concern of the sulbasutra is geometry alone, although some observations of the srauta nature and certain mathematical operations connected with geometry also find mention in these texts. It is worth noting that the geometry of the sulbasutra has more affinity to modern engineering practice than to theoretical mathematics of the present times. This is natural given that the Vedic geometers were more concerned with accurate constructions of ritual altars and the altar space than with proving a theorem.
The essence of the sulbasutras lies more in the concepts discussed therein than in the authors’ use of grammatical accentuation. The latter was incidental Baudhayana employed the then prevalent style of the sutra and the other authors followed in a similar fashion. One of the reasons for the perhaps inaccurate reproduction of the geometry of the sulbasutra may be the approach adopted by later commentators, an approach that was affected by strongly pre-conceived grammatical notions. Instead, the sulbasutras ought to be approached with an inquiring mind regarding the meanings of the words in association exclusively with the subject under discussion. The modern Indian commentators further tend to find arithmetical and mathematical references in the sulbasutra, references that are unlikely to have been intended as such by the authors. One of the acid tests for the accuracy of presentation of a particular meaning is whether it may result in constructions of the Vedic style. Thus, while?2 is of great concern to the sulbavid (author of a sulbasutra) the same may not be said of?3 which is irrelevant to Vedic constructions, although more recent commentators have interpreted the sulbasutras to ascribe relevance to this numerical value.
The sulbasutra on the other hand reveal a great degree of development of geometry not only as applied to techniques of constructions, but also extending to conceptual symmetries and an unknown methodology of evolution of the conceptual approach to such geometry. While this is the very approach to basic geometry, it then becomes a passionate progress to various shapes of the uttaravedis. In fact, the very geometry of the mahavedi, in which the uttaravedi is an element, is of unique conceptual beauty. The 30-36-24 regular trapezium of the mahavedi contained several triples in their construction format such as 3-4-5, 12-5-13,15-9-17, 35-12-37 which could be employed to attain the accuracy of layout. The area of the mahavedi thus being 972 square of 18 prakramam, the uttaravedis were initially of 1/3rd of 972 and at the same time the square of 18. Then 1.3rd of 324 is 108, an important number since ancient times for obvious reasons. A trapezium shape of 10-12-8 amounting to an area of 108 thus became the smallest size of the uttaravedi in prakramam measures.
Figure 1: Mahavedi
The taper of this trapezium narrowing down to the east is impressed upon by all the sulba texts. The eastward striving nature of the uttaravedi (for, gods reside at the east) is of paramount importance to the vedic rituals and one could not possibly say for what long period of time it took, to later develop into highly complex and realistic geometrical shapes in the form of three later uttaravedis, meant as kamyaciti. In the further development of the uttaravedis, the concept of “saptavidha: sampadyate”, meaning that the area of the uttaravedi should follow a certain pattern became a great spirit of enquiry. The eastward striving nature and this new concept put together developed into highly complex and yet beautifully conceived geometrical shapes of symmetry perhaps unparalleled in the history of geometry and mathematics. It is at an unknown point of time after that Baudhayana stood and decided to document it for posterity. And it is this very thing that the modern commentators, in a way, failed to redeem and realise.
At the very first, the term “saptavidha:” was insufficiently interpreted to mean as 7.5 times the purusam measure, whereas it was really referred to as the 7 stages of development from the 7.5 to the 101 as area and corresponding sizes. Later, Katyayana described this in good detail, which also went properly not delineated. While Manava updated to the mathematical order of his time and described several types of equalities and arithmetical series, it was ironically Apastamba who was accredited with several modern mathematical interpretations. As a whole, it would be fair to state that the magnificent total geometry of the sulbasutra remains undiscovered as on date. The BSS contains 21 major sutra sets, of which the first two describe basic geometrical constructs. They contain basic units of measurements, conversions from one shape to another of equal area, notions of right angles and the value of ?2 etc. Sutra 3 and 4 describe the geometry and general concepts of the total altar space. Sutra 5 and 6 are general in nature as well, but in sutra 7 an initiation of the geometrical complexities to follow is indicated by the description of the new garhapatyaciti of 21 bricks.
The general layout of the pracinasala and mahavedi, with a detailed definition of the position of the uttaravedi, is already clear at this point, since it uses the rathacakraciti with its well-defined centre for the purpose. The next 14 sutras are devoted to the various formats of the uttaravedi.
After describing 2 brick-laying orders of the pithan syenaciti, syenaciti of pancapatri, sadpatri, kanka and alaja forms are described. These distinct bird shaped altars used different methods to fulfill the “saptavidha:” concept with the7.5 purusam square as the basis. All of them are based on clear symmetries and on basic formative squares and rectangles. Next, two simple triangular praugaciti are described. Then the geometrical content is intensified to describe the rathacakraciti, 3 dronociti, the smasanaciti, and the kurmaciti. Esoteric compositions are displayed in the final sutra which goes beyond the bounds set by basic, definitive principles. It is possible that this process of creative design and constructions was already declining before the time of Baudhayana and this motivated him to create the BSS text.
While going through the BSS text, one may doubt that all of the citi formats described by him were in practice during his time since the descriptions contain varying levels of details, though each of the descriptions could be termed as sufficient in itself. It is here and in the unknown nature of the time line that the strength of the sruti is revealed in its capacity to travel intact wide expanses of time. Indeed there are very specific examples of such demonstration of strength of the system in its further travel to our present times. What is more demonstrative in the second period of about 2800 years since Baudhayana is that the text travelled intact almost without its meanings really taken in. And yet there are words in the BSS which could have easily got transformed into something else but did not. Then there are such instances where certain versions of the manuscripts tried to inject words into the body text which were found to be stoically resisted by the extant contents.
In comparison, the later sulbasutra texts are explanatory in nature with some additional altar designs and some mathematical updates by the authors. These have definitely added strength to the information system on the one hand and then silently declared that they have stepped out of the sruti circuit to certain extent. The very sruti system might indeed have had several parallel flows where the sulbasutra and that of the ritualistic practices could have existed even without mixing. Where some amount of cross references only existed without one being part and parcel of the other is a distinct possibility. And possibilities for further studies are plentiful, as the present attempt of delineation of the sulbasutra could open up a better historical perspective and the timeline of the progress of not only geometry and mathematics of the period of first millenium BC but a host of other related subjects. It provides a better clarity to matters beyond the second millennium BC as well. For the geometrician of today and such enthusiasts, a large volume of exercise is provided by Katyayana, as his formulae for taking the citi forms from 7.5 to 101 purusam squares remain untested and untried.
A Few Sutras
An extract from the book
with Commentary by Parameswaran Murthiyedath
Sutra 12 (Kankaciti)
Sutra 12.1
Kankacita etenatma
Puccam ca vyakhyatam
(The Kankacita defined here will have a body and a tail)
The Kankacita is known to have the shape of a heron.
Sutra 12.2
sirasi pancopadadhyat
sirasi pancopadadhya
(the head will be obtained as 5 by definition of its shape)
As per the definition the head will be obtained as 5.
This states that the length of the head along the east west is 5 aratni from the body. With the same words a meaning that the area of the head is 5 sq. aratni could also be derived. Both meanings are true and so meant.
Sutra 12.3
Saptapancasaddaksine paksa upadadhyat
Saptapancasaddaksinepaksa upadadhya
(5 and 7 to south the wing will be obtained next the north)
The wing at south will be obtained as 5 and 7and likewise the north. Again, The wing tips are at a distance of 12aratni’s to south (5+7) and at the same time it means that the area of the wings are 57 sq. aratni.
Sutra 12.4
Vyayamena sapradesna paksayorapanamah
pancamabhagiyardhyabhih sat sat patrani kuryat
adhyardhavasisyate vyayamena
sat sat
patrani kuryat
(by vyayama measure with the pradesa the wings bent with the pancami and adhyardha six and six wing cuts as stated an adhyardha will be balanced)
Figure 2: Karika city layout (BSS-12.2-6)
(The wings will be set out at a measure of 1 vyayama added with 1 pradesa at an angle and the wings tips will have six notches of a measurement of 1 pancami by 1 pancami and a half. An adhyardha will be balanced)
The configuration of the wings are made by the diagonal of a square of 108A first taken forward and then retraced to give a mirrored bent. The sutra further categorically states that the wing tips configuration is with 6 nos of 1aratni by 1 adhyardha cuts. This adds to the area of 54 sq. aratni and additional 3aratni and the statement of 57 sq. aratni are now established. The statement ‘adhyardhavasisyate’ is about the excess area resulted amounting to 1½ aratni in the configuration which will be later adjusted by the leg trimming of the tail.
Fig. 12.1 given here shows the citi geometry. First a basic square 1-2-3-4 will be established with side as 144A, deriving from the statement of ‘saratnipradesa’. The south end of the wings from which the wing tips take off is line 9-10, parallel to1-4 and at a distance of 12 aratni (288A). Line 4-8 is the diagonal of a square of 108A as side. Line 8-9 is mirrored from line 4-8. Thus the wing formation of 4-8-9-10-13-1 is established. The six wing tips are formed by the diagonals of boxes of an aratni by an adhyardha (1½ aratni) as sides, as shown within9-10-11-12.
Sutra 12.5
taya pucchasyavastat
pradesavyasau bhavatah
dvaudvavastamabhagau pragbhedavupadadhyat
taya pucchasyavastat
pradesavyasau bhavatah
(At the backside of the tail feet of an aratni length in an aratni gap with 1 pradesa as width at the back and near as 2 and 2, and 8 sided with a forward cut will be obtained)
The tail is having a forward cut of 1 aratni length and 1 pradesa as width of sides, in a gap of 1 aratni, and thus having 8 sides split into two as forward cut.
The tail portion of 15-14-16-17 contains the details mentioned above. Thus the tail have two cuts of 1 aratni square which is modified to form the root and two such feet are placed touching each other as stated forming an 8 sided cut in total.
A statement like ‘pancadasa pucche’ is judiciously left out for the reason of the cut in the tail, though the overall outline agreed to such a statement. Further in sutra 12.8 the placement of two astamsi bricks at the tail to obtain this configuration are mentioned, to which the presentation here corresponds.
Figure 2: Karika city layer 1
Sutra 12.6
evam saratnipradesah saptavidhah sampadyate
evam saratnipradesah
saptavidhah sampadyate
(With only the aratni and pradesa the saptavidhah concept will be achieved)
Thus with the aratni and pradesa measures alone, the saptavidhah concept will be achieved. Indeed, the altar shape graphically feeds back an area report of exactly 7.5 times the purusam square, as could also be seen from the calculation of area given here.
Table 1: Area of Kankacit
Sutra 12.7
athestakanam vikarah
padestakam caturbhih
Figure 4: Karika city, Layer 2
pradesena pradesasavises eneti
adhyardhestakam caturbhih parigrhniyadardhavyayamena
dvabhyamaratnibhyamaratnisavises eneti
tah sat
Figure 5: Karika city, Bricks
pancamabhagiyah savayavah
padestakam caturbhih
pradesena pradesasavises eneti
dvabhyamaratnibhyamaratnisavises eneti
tah sat
Now the bricks configuration with the pancami all over with the pada square brick with surrounded (sliced) ardha and pradesa and the adhyardha and pradesa and the adhyardha and pradesa with pradesa and a modified pradesa with the adhyardha brick from a square brick with the surrounded (sliced) half vyayama by two and by aratni and aratni modified like that six.
With pancami as the basic brick allover with the pada of a square brick, and the ardha, the adhyardhardha and pradesa sliced, the vyayama and the aratni sliced, the modified aratni consisting 6 bricks will be used.
However, some more bricks are found required and the lists of bricks are as given below:
Sutra 12.8
sesam yathayogam
yathasamkhyam yathaadharmam
with these the caturasrapadyah and 8 divided part at the wings having placed balance as required in as many numbers as per rules be placed
The caturasrapadyah and the astamsi bricks having placed as the feet, the balance will be filled with the required numbers as per rules.
Table 2: Kanchita Bricks
Parameswaran Murthiyedath is a scholar of Vedic Mathematics. From “Kriti Rakshana”, National Mission for Manuscripta.



This lecture has been prepared by N.R. Srinivasan for the Vedanta Class at Sri Ganesha Temple at Nashville by extracting, abridging and editing texts from the following:

  1. Will Durant, The Story of Civilization, Vol. I, Simon & Schuster, U.S.A.
  2. Reader's Digest, Book of Facts 1987, Readers Digest Association Inc., U.S.A.
  3. R. Kumar, North American Panchangam2006, The Hindu Society of American Temples, U.S.A.
  4. Ed. Viswanathan, Am I A Hindu? Rupa & Co., New Delhi.
  5. Swami Harshananda, An Introduction to Hindu Culture, Ramakrishna Math, Bangalore, India.
  6. Dr. N.S. Anantha Rangacharya, Selections from the Upanishads, Bangalore, India, 2002.