Sunday, May 22, 2016

Indian Chemist discovers the secrets of Agastya Samhita in 1927!

Indian Chemist discovers the secrets of Agastya Samhita in 1927!

Indian Chemist discovers the secrets of Agastya Samhita in 1927!

What was probably the first non-stop flight was made not from New York to Paris but from Ceylon to a place near modern Delhi, if the records are correct.
According to the Sanskrit epic, Ramayana, a story many centuries older than the Greek epics, an Indian king made this trip in a balloon in five days.  His carriage was called“Pushpaka”, meaning “butter-fly-like” and the epic contains a detailed account of preparations for the flight, with a vivid description of the balloon itself.
What is more convincing evidence that the trip was actually made, is the fact that the poem contains an accurate and beautifully written description of an aerial view of the various cities and countries passed over on the journey.  Only a super imagination could have conceived this perspective and picture.
It is due to the investigations of Varam R. Kokatnur (’14 M.S., ’16 Ph.D) that this and many other fascinating discoveries about the learning of ancient India have been made available.  Dr. Kokatnur is a consulting chemist by profession, having his business in New York City; but his hobby is the study of hieroglyphics; and it was while tracing the relation of Sanskrit to the hieroglyphics that he discovered valuable information which will greatly affect our present knowledge of history of chemistry.
Agastya SamhitaWhen the American Chemical Society met in Detroit, Michigan, from September 5 to 10, Dr Kokatnur read a paper containing evidences to show that Cavendish and Priestly were not the first men to discover hydrogen and oxygen, but that these gases had been known to the sages of ancient India, and then he read a second paper to show that chemistry was of Aryan and not Semitic origin. 
After listening to the proofs he offered, members of the convention gave the author a special vote of thanks for the originality and value of his researches and agreed that his evidences were conclusive.  The papers, as read by Dr. Kokatnur, will soon be published in the Isis, a scientific journal published in many languages.  The publication of this article in the ALUMNI WEEKLY precedes all other announcements.
Dr. Kokatnur is a native of India, educated in Bombay University and the University of California as well as Minnesota.  He was a Shevlin fellow in Chemistry, is a fellow of the American Institute of Chemists, a member of Sigma Xi and many other scientific societies.
While working on his study of hieroglyphics, he came across a Sanskrit book which contained four pages of an old but well-known manuscript which was written in 1350 and contains the collected writings of Agastya.  These few pages were discovered by Vase in the library of an Indian prince, in 1924, in Ujjain, India.
Agastya is a  sage whose name has been mentioned in Indian writings as far back as 2000 B.C.  Consequently, this manuscript, which is known as “Agastya-Samhita” if authentic, is extremely old as far as source material is concerned, belonging to post-Vedic and pre-epic times.
Being a chemist, Dr. Kokatnur naturally seized this manuscript with avidity for the sage Agastya is credited with being the discoverer of hydrogen and oxygen, the dry electric battery, electro-plating, kites, hot-air blimps and propelled balloons.  In fact, he is named variously after his discoveries, in contrast with the present practice naming the discoveries after one’s name.  Thus he is called “pot-born” (dry electric battery); “cathode-anode” (electricity); “conquerer of kites and blimps”, and so forth.  It is as if we should call Henry Ford, “Flivver”, and Mr Edison “incandescent lamps”, “movie” or “Dictaphone”.
In this manuscript, the mention of hydrogen and oxygen is made only incidentally in connection with the construction of the balloon.  Of course, Agastya did not know the gases by these names, but his terms for them are more specific than ours.  Hydrogen is called “upfaced” because of its lightness; while oxygen is known as “vital” or “essential to life”.  He did not use the word “gas” but called them “airs”.  In the English language, hydrogen is so-called because water is generated by its combustion, and oxygen was named by Lavoisier from the Greek root meaning “acid” because he believed it to be an essential part of every acid.  In the German language, hydrogen is “wasserstoffe” and oxygen “sauerstoffe”, meaning the same but being also inaccurate, for all acids do not contain oxygen.  How much more accurate were Agastya’s names than ours?  The originality and aptness of these names is cited by Dr. Kokatnur as one evidence that the manuscript must be authentic.
Chemists at the convention gasped when Dr. Kokatnur read to them the following translation of the method of making a dry electric battery which was written centuries before the Christian era:
Minnesota Alumni Weekly“A well-cleaned copper plate should be placed in an earthen-ware vessel.  It should then be covered first by moist sawdust.  Mercury amalgamated zinc plate should then be placed on the top of the saw-dust.  By their contact a light known by the twin-names Mitra-Varuna (cathode-anode or electricity) is produced.  The water is split up by this into gases, Vital and Up-faced.  The joining together of hundred such vessels is very active or effective.”
From his knowledge of Chemistry, Dr. Kokatnur recognized that this was the method used in making a dry battery, but did not know what part the mercury amalgamated zinc plate had in the reaction until he consulted a battery maker who explained that it prevented polarization.
Continuing, Agastya said:
“When the “up-faced” is filled in an air-proof (impervious) bag and the bag is tied at the head of the vehicle, the “up-faced” due to its lightness carries the vehicle in the sky.”
Then the process of air-proofing the balloon bag is explained.  This is to be done by dipping a silk bag in the bark of trees which produce a milky juice (probably rubber).  After the first immersion and drying it was again dipped in the juice of another tree which contains tannin.  Then it is dried again, coated with wax, and at last coated with some kind of mixture made from sugar and lime.
Only to a chemist would the original translation have meant anything, for the manuscript does not specifically state that tamin is the second juice used.  The tree is named, and from his knowledge of Chemistry, Dr. Kokatnur deduced that the desired juice might be tannin for that is one of the chemicals contained in the sap of this particular tree. He consulted a rubber chemist and found that tannin will coagulate rubber (latex). 

After he has explained the process of making a dry electric battery, the sage Agastya gives us the process of electroplating:
“(This great light) plates the copper with gold or silver in the presence of acidified water and the metal that is combined with saltpeter.  The gold-plated copper is called “hundred pot born”.  Apparently the metal combined with saltpeter is either gold nitrate, gold chloride or gold cyanide. 
According to ancient literature, the Indians of pre-Christian times knew the laws of air and water and recognized that they were similar, except that in water one moves on the surface and in the air one must travel through the body of the matter.  Manuscripts written in 800 B.C. show that they had a knowledge of physics, for it is specifically stated that light, heat and sound exist in waves. 
They knew how to take advantage of currents both in the air and on the water.  Their balloons were steered by sails and guided by specially bred birds which must have been crossed to produce a bird of unusual strength which could be easily trained.  Hundreds of such birds were tied to the balloon described in the epic, Ramayana.  In the translation made by Romesh C Dutt, which is a condensed version of the Sanskrit original, we find in Book Five that Rama, the hero, had met and consulted with Agastya.  Dutt says:
“The wanderings of Rama in the Deccan, his meeting with Saint Agastya, and his residence on the banks of the Godavari river, are narrated in this Book.  The name of Agastya is connected with the Deccan, and many are the legends told of this great Saint before whom the Bindhya mountains bent in awe, and by whose might the Southern ocean was drained.  It is likely that some religious teacher of that name first penetrated beyond the Vindhyras in the Deccan, three thousand years ago.”
According to the epic, Agastya gave Rama magic weapons with which to conquer his foes.  There is not space here to relate the story, but it closes with Rama, returning home victorious with his rescued bride Sita, in an aerial carriage.  Dutt’s translation continues:
“Mark my love,” so Rama uttered, as on flying Pushpa car, 
borne by swans, the home-returning exiles left the field of war.
Lanka’s proud and castled city on the Trikuta’s triple crest, 
As on peaks of bold Kailasa mansions of Immortals rest!
See my love, round Ceylon’s island 
how the ocean billows roar
Hiding pearls in caves of corals, strewing shells upon the shore,
And the causeway, far-extending – 
monument of Rama’s fame – 
“Rama’s Bridge” to distant ages shall our deathless deeds proclaim!
See the rockbound fair Kishkindha and
her mountain-girdled town,
Where I slayed the warrior Bali, placed Sugriva on the throne.
And the hill of Rishyamuka where Sugriva first I met,
Gave him word – he would be monarch
ere the evening’s sun had set.
See the sacred lake of Pampa by whose wild and echoing shore,
Rama poured his lamentations when he 
saw his wife no more,
And the woods of Janasthana where
Jatayu fought and bled,
When the deep deceitful Ravan with
my trusting Sita fled.”
Of course, such poetic descriptions have always been given legendary, poetic interpretations, but we know that many arts known to the ancients have been lost.
No one can say definitely that this balloon flight as described was actually made, but Dr. Kokatnur has a number of evidences to substantiate his belief in the authenticity of the manuscript, Àgastya-Samhita`.
“In the first place”, he says, “the fact that the voltaic cell was discovered only a century ago and that the remedies to prevent polarization were discovered still more recently, indicate that the manuscript, to include these elements must be, if a fake, of very recent origin.  It is easy to detect if a manuscript is 50 years or several centuries old by examining the condition of the paper and writing.  These appear to be in favour of its authenticity. Further, it is not often that a man is well enough versed both in science and language to execute a fraud successfully is found.
“In India the knowledge of the sciences is only available in the English language.  It is doubtful if any Indian English-educated chemists – there are no electro-chemists by the way – know the fact that amalgamated zinc prevents polarization, and if one did, the chance of his knowing Sanskrit well enough to fake such a manuscript is remote.”
“The names of the twin-gods “Mitra Varuna” is very old and is even mentioned in Rik-Veda.  The word “Mitra” means “friend”, “an ally”, in other words, “cathode” because a deposit is made at this place.  “Varuna” means “liquefied or enemy” (of zinc) and therefore “anode”.  The use of such a twin word with such a significant meaning is certainly highly original.
“Similarly the names “prana” “vital life” and “udana” (up-faced or upward-moving) for oxygen and hydrogen are equally original and significant.
“Hindus seem to know of gases and there is no question of the antiquity of such knowledge.  From times immemorial, the twice-born castes of India have repeatedly chanted certain prayers, wherein som of these gases are mentioned.  One of the prayers of undoubted antiquity, repeated every day in India by the twice-born at the time of meals, somewhat in the spirit of a Christian blessing, is as follows:
“I reside in the animal body in the form of digestive fire (animal heat) and with the aid of Prana and Apana gases, digest the four kinds of foods”.
“If the knowledge of these gases were an isolated instance, one might well believe the fraudulent nature of this manuscript.  But the high concurrent knowledge of Chemistry in India is a never-to-be-disputed fact.  Their knowledge of the preparation of mild and caustic alkali several centuries before the Christian era, their knowledge of aqua-regia in potential, the detection of metals by the colour of their flames, the recognition of zinc as a distinctive metal many centuries before it was definitely known as such in Europe, and above all the great monuments like the ten-ton wrought iron gun at Nurver, as prerequisites point to the authenticity of this manuscript.”
~ The Minnesota Alumni Weekly, Volume 27, Number 3, July 1927.  Edited by Leland F. Leland

Thursday, February 11, 2016

Origin, Principles, Practice and Types of Yoga

Origin, Principles, Practice and Types of Yoga

Yoga is a family of ancient spiritual practices that originated in India, where it remains a vibrant living tradition and is seen as a means to enlightenment. 

Karma Yoga, Bhakti Yoga, Jnana Yoga, and Raja Yoga are considered the four main yogas, but there are many other types. In other parts of the world where yoga is popular, notably the United States, yoga has become associated with the asanas (postures) of Hatha Yoga, which are popular as fitness exercises. Yoga as a means to enlightenment is central to Hinduism, Buddhism, Sikhism, and Jainism, and has influenced other religious and spiritual practices throughout the world. Important Hindu texts establishing the basis for yoga include the Yoga Sutras of Patanjali, the Bhagavad Gita, and the Hatha Yoga Pradipika.

Yoga practice and intention

Modern yoga practice often includes traditional elements inherited from Hinduism, such as moral and ethical principles, postures designed to keep the body fit, spiritual philosophy, instruction by a guru, chanting of mantras (sacred syllables), quietening the breath, and stilling the mind through meditation. These elements are sometimes adapted to meet the needs of non-Hindu practitioners.
Proponents of yoga see daily practice as beneficial in itself, leading to improved health, emotional well-being, mental clarity, and joy in living. (Some skeptics question these claims.) Yoga adepts progress toward the experience of samadhi, an advanced state of meditation where there is absorption in inner ecstasy.
The goals of yoga are expressed differently in different traditions. In theistic Hinduism, yoga may be seen as a set of practices intended to bring people closer to God - to help them achieve union with God. In Buddhism, which does not postulate a creator-type God, yoga may help people deepen their wisdom, compassion, and insight. In Western nations, where there is a strong emphasis on individualism, yoga practice may be an extension of the search for meaning in self, and integration of the different aspects of being. The terms Self-Realization and God-Realization are used interchangeably in Hindu yoga, with the underlying belief that the true nature of self, revealed through the practice of yoga, is of the same nature as God.
The ultimate goal of yoga is the attainment of liberation (Moksha) from worldly suffering and the cycle of birth and death (Samsara). Yoga entails mastery over the body, mind, and emotional self, and transcendence of desire. It is said to lead gradually to knowledge of the true nature of reality. The Yogi reaches an enlightened state where there is a cessation of thought and an experience of blissful union. This union may be of the individual soul (Atman) with the supreme Reality (Brahman), as in Vedanta philosophy; or with a specific god or goddess, as in theistic forms of Hinduism and some forms of Buddhism. Enlightenment may also be described as extinction of the limited ego, and direct and lasting perception of the non-dual nature of the universe.
For the average person still far from enlightenment, yoga can be a way of increasing one's love for God, or cultivating compassion and insight. While the history of yoga strongly connects it with Hinduism, proponents claim that yoga is not a religion itself, but contains practical steps which can benefit people of all religions, as well as those who do not consider themselves religious.

The word "yoga"

The word "yoga" – from the Sanskrit root yuj ("to yoke") – is generally translated as "union of the individual atma (loosely translated to mean soul) with Paramatma, the universal soul." This may be understood as union with the Divine by integration of body, mind, and spirit. Thus, in essence, one who attempts yoga may loosely be referred to as a yogi or in Sanskrit, a yogin (masculine) or yogini (feminine). These designations are actually intended for advanced practitioners , who have already made considerable progress along the path, towards yoga.(Ajit,2005)

Diversity of yoga

Over the long history of yoga, different schools have emerged, and there are numerous examples of subdivisions and synthesis. It is common to speak of each form of yoga as a "path" to enlightenment. Thus, yoga may include love and devotion (as in Bhakti Yoga), selfless work (as in Karma Yoga), knowledge and discernment (as in Jnana Yoga), or an eight-limbed system of disciplines emphasizing meditation (as in Raja Yoga). These practices occupy a continuum from the religious to the scientific. They need not be mutually exclusive. (A person who follows the path of selfless work might also cultivate some knowledge and devotion.) Some people (particularly in Western cultures) pursue yoga as exercise divorced from spiritual practice.
Other types of yoga include Mantra Yoga, Kundalini Yoga,Iyengar Yoga, Kriya Yoga, Integral Yoga, Nitya Yoga, Maha Yoga, Purna Yoga, Anahata Yoga, Tantra Yoga, Tibetan Yoga, etc. It is often helpful to check the teacher and lineage to be sure how these terms are being used. Another name for Raja Yoga ("royal yoga") is Ashtanga Yoga ("eight-limbed yoga"), but this should not be confused with the Ashtanga Vinyasa Yoga developed by Sri K. Pattabhi Jois, which is a specific style of Hatha Yoga practice.

Yoga and religion

In the Hindu, Buddhist, Sikh, and Jain traditions, the spiritual goals of yoga are seen as inseparable from the religions of which yoga forms a part. Some yogis make a subtle distinction between religion and yoga, seeing religion as more concerned with culture, values, beliefs and rituals; and yoga as more concerned with Self-Realization, i.e., direct perception of the ultimate truth. In this sense, religion and yoga are complementary. Sri Ramakrishna likened religion to the husk, and direct experience to the kernel. Both are needed, "but if one wants to get at the kernel itself, he must remove the husk of the grain."
Some forms of yoga come replete with a rich iconography, while others are more austere and minimalist. Hindu practitioners of yoga are proud of their religious traditions, while non-Hindu practitioners claim that yoga may be practiced sincerely by those who have not accepted the Hindu religion.
While the yoga tradition remains rooted in India, the fact that some modern yogis like Swami Vivekananda and Paramahansa Yogananda came to the West suggests that they saw hope the yoga tradition could also flourish there. Critics of yoga as practiced in the West charge that it is sometimes watered down, corrupted, or cut off from its spiritual roots (e.g. the popular view that yoga is primarily physical exercises).
If yoga is one of India's great gifts to the world, the widespread acceptance of that gift - with the concomitant diversity - is sometimes incomprehensible to traditional Hindu practitioners of yoga. Yet the sheer number of people practicing yoga outside India suggests the need to define yoga both by its historical roots and its modern adaptations.

Common themes

Common to most forms of yoga is the practice of concentration (dharana) and meditation (dhyana). Dharana, according to Patanjali's definition, is the "binding of consciousness to a single point." The awareness is concentrated on a fine point of sensation (such as that of the breath entering and leaving the nostrils). Sustained single-pointed concentration gradually leads to meditation (dhyana), in which the inner faculties are able to expand and merge with something vast. Meditators sometimes report feelings of peace, joy, and oneness.
The focus of meditation may differ from school to school, e.g. meditation on one of the chakras, such as the heart center (anahata) or the third eye (ajna); or meditation on a particular deity, such as Krishna; or on a quality like peace. Non-dualist schools such as Advaita Vedanta may stress meditation on the Supreme with no form or qualities (Nirguna Brahman). This resembles Buddhist meditation on the Void.
Another common element is the spiritual teacher (guru in Sanskrit; lama in Tibetan). While emphasized to varying degrees by all schools of yoga, in some the guru is seen as an embodiment of the Divine. The guru guides the student (shishya or chela) through yogic discipline from the beginning. Thus, the novice yoga student is to find and devote himself to a satguru (true teacher). Traditionally, knowledge of yoga--as well as permission to practice it or teach it--has been passed down through initiatory chains of gurus and their students. This is called guruparampara.
The yoga tradition is one of practical experience, but also incorporates texts which explain the techniques and philosophy of yoga. Many gurus write on the subject, either providing modern translations and elucidations of classical texts, or explaining how their particular teachings should be followed. A guru may also found an ashram or order of monks; these comprise the institutions of yoga. The yoga tradition has also been a fertile source of inspiration for poetry, music, dance, and art.
When students associate with a particular teacher, school, ashram or order, this naturally creates yoga communities where there are shared practices. Chanting of mantras such as Aum, singing of spiritual songs, and studying sacred texts are all common themes. The importance of any one element may differ from school to school, or student to student. Differences do not always reflect disagreement, but rather a multitude of approaches meant to serve students of differing needs, background and temperament.
The yogi is sometimes portrayed as going beyond rules-based morality. This does not mean that a yogi will act in an immoral fashion, but rather that he or she will act with direct knowledge of the supreme Reality. In some legends, a yogi--having amassed merit through spiritual practice--may then cause mischief even to the gods. Some yogis in history have been naked ascetics--such as Swami Trailanga, who greatly vexed the occupying British in 19th century Benares by wandering about in a state of innocence.


Images of a meditating yogi from the Indus Valley Civilization are thought to be 6 to 7 thousand years old. The earliest written accounts of yoga appear in the Rig Veda, which began to be codified between 1500 and 1200 BC. It is difficult to establish the date of yoga from this as the Rig Veda was orally transmitted for at least a millennium. The first Yoga text dates to around the 2nd century BC by Patanjali, and prescribes adherence to "eight limbs" (the sum of which constitute "Ashtanga Yoga") to quiet one's mind and merge with the infinite.
The first full description of the principles and goals of yoga are found in the Upanisads, thought to have been composed between the eighth and fourth centuries BC. The Upanisads are also called Vedanta since they constitute the end or conclusion of the Vedas (the traditional body of spiritual wisdom). In the Upanisads, the older practises of offering sacrifices and ceremonies to appease external gods gives way instead to a new understanding that man can, by means of an inner sacrifice, become one with the Supreme Being (referred to as Brahman or Mahatman) -- through moral culture, restraint and training of the mind.

Hindu yoga

Bhagavad Gita

The Bhagavad Gita famously distinguishes several types of "yoga", corresponding to the duties of different nature of people. Capturing the essence and at the same time going into detail about the various Yogas and their philosophies, it constantly refers to itself as such, the "Scripture of Yoga" (see the final verses of each chapter). The book is thought to have been written some time between the 5th and the 2nd century BC. In it, Krishna describes the following yogas:
  1. Karma yoga, the yoga of "action" in the world.
  2. Jnana yoga, the yoga of knowledge and intellectual endeavor.
  3. Bhakti yoga, the yoga of devotion to a deity (for example, to Krishna).


Perhaps the classic description of yoga is the Yoga Sutras of Patanjali, which form the basis not only of the darshana called "yoga"--one of six such "orthodox" (i.e. Veda-accepting) schools of Hindu philosophy--but also of the practice of yoga in most ashrams (to the extent these can be distinguished). 
The school (dharshana) of Indian philosophy known as "yoga" is primarily Upanishadic with roots in Samkhya, and some scholars see some influence from Buddhism. The Yoga philosophy fully believes in the epistemology of the Samkhya school, as well as its concept of the individual spirits (Purusha) and the Nature (Prakriti)—but differs from Samkhya's atheism.
Patanjali in the Yoga Sutras presents the goal of yoga as 'the cessation of mental fluctuations' (cittavrtti nirodha), an achievement which gives rise to the possibility of stable meditation and thus deeper states of absorption (dhyana or samadhi). This requires considerable restraint (yama) and self-discipline (niyama; see below for Patanjali's eight limbs of yoga)). Patanjali's yoga is sometimes called Raja Yoga (Skt: "Royal yoga") or "Ashtanga Yoga" ("Eight-Limbed Yoga"), in order to distinguish it from Hatha yoga. It is held as authoritative by all schools. Patanjali is also known for writing commentaries (Mahabhashya) on the Sutras of the great Sanskrit grammarian Panini. In fact, Panini, Patanjali and Katyayana are regarded are the highest authority not only in Sanskrit but also in the whole of Linguistics.
Patanjali's text sets forth eight "limbs" of yoga practice. Interestingly, only one of them involves physical postures (and these mainly involve seated positions). The eight are:
  1. Yama (The five "abstentions"): violence, lying, theft, (illicit-) sex, and possessions
  2. Niyama (The five "observances"): purity, contentment, austerities, study, and surrender to God
  3. Asana: This term literally means "seat," and originally referred mainly to seated positions. With the rise of Hatha yoga, it came to be used of these yoga "postures" as well.
  4. Pranayama: Control of prana or vital breath
  5. Pratyahara ("Abstraction"): "that by which the senses do not come into contact with their objects and, as it were, follow the nature of the mind." — Vyasa
  6. Dharana ("Concentration"): Fixing the attention on a single object
  7. Dhyana ("Meditation")
  8. Samadhi: Super-conscious state or trance (state of liberation)

God in Yoga philosophy

The philosophy of Yoga also presented certain arguments for the existence of God (Ishvara, lit., the Supreme Lord):
  • The Vedas are regarded as evidence. The Vedas and their commentaries, the Upanishads mention and describe God—hence God exists.
  • Continuity: people and things have various degrees of differences among themselves. Some people are foolish, some are wise. Hence there ought to be some Being who has the highest level of knowledge among all—who is omniscient. That Being is God
  • Cosmic Evolution, leading to this universe, occurs because of the contact between Purusha (spirit) and Prakriti (Nature). Purusha is static, and Prakriti is unconscious. Hence there can be no contact between these two things of opposite characteristics, unless God—the omniscient Being—brings about this contact.
  • Meditation upon God is regarded as the best means of attaining Liberation. If meditation on such a Being helps in liberation, and all obstacles are removed, then the object of the meditation must have a real existence.
Ishvara is regarded as a special Purusha, who is beyond sorrow and Karma laws. He is one, perfect, infinite, omniscient, omnipresent, omnipotent and eternal. He is beyond the three qualities of Sattva, Rajas and Tamas. He is different from an ordinary liberated spirit, because the latter were bound once, whereas Ishvara was never bound. He is kind and merciful. He is the father of the demigods (the various Devas) and of the sages (rishis), as well as their guru; He is the author of the Vedas.
Yoga system is perhaps the first philosophy in the world to give arguments for monotheism. Yoga says that Ishvara can be only one and unique. If many Gods are assumed:
  • Let's say if they are two Gods. If God #1 gives a certain quality (say white color) to a thing and God #2 gives another (say black color) to the same thing, this would be mutually contradictory. On the other hand, if God #1's choice reigns supreme, God #2 would fail to remain as God
  • Let's say that the Gods work in as a committee to do certain tasks one by one. Then while one God is doing his work, the existence of the other Gods would be superfluous and unnecessary.

Hatha yoga

Over the last century the term yoga has come to be especially associated with the postures (Sanskrit asanas) of hatha yoga ("Forced Yoga"). Hatha yoga has gained wide popularity outside of India and traditional yoga-practicing religions, and the postures are sometimes presented as entirely secular or non-spiritual in nature.
Traditional Hatha Yoga is a complete yogic path, including moral disciplines, physical exercises (e.g., postures and breath control), and meditation, and encompasses far more than the yoga of postures and exercises practiced in the West as physical culture. The seminal work on Hatha Yoga is the Hatha Yoga Pradipika, written by Swami Svatmarama.
Hatha Yoga was invented to provide a form of physical purification and training that would prepare aspirants for the higher training that is called Raja Yoga (see above). This is still true today. Despite this, many in the West practice 'Hatha yoga' solely for the perceived health benefits it provides, and not as a path to enlightenment.

Natya yoga

The guide to Natya (Dance) Yoga was written by Bharata Muni. 
Sage Narada along with Gandharvas were the first to practise Natya Yoga, which comprise all the four main yoga's. Natya Yoga was practised by the medieval devadasis, and is currently taught in a few orthodox schools of Bharatanatyam and Odissi.

Buddhist yoga

Within the various schools of Tibetan Buddhism yoga likewise holds a central place, though not in the form presented by Patanjali or the Gita. (For example, physical postures are rarely practiced.) An example would be "guru yoga," the union with the mind of the spiritual teacher which must be done at the beginning of the spiritual path and regularly throughout. In the tantric traditions a number of practices are classified with the name "yoga", for example, the two of the four general classification of tantras--"Yoga Tantra" and "Highest Yoga Tantra".
A system of 108 bodily postures practiced with breath and heart rhythm timing in movement exercises is known as Thrul-Khor or union of moon and sun (channel) prajna energies. The body postures of tibetan ancient yogis are depicted on the walls of the Dalai Lama's summer temple of Lukhang.
As the whole buddhist lineage transmission of Kagyu school came to Tibet over the Indian Yogis Naropa, Tilopa, Marpa then Milarepa, Gampopa, authentic old buddhist yogic practices have been passed over to students still following these instructions throughout many Kagyu Monasteries and institutes worldwide.
Yogacara ("Yoga Adepts"), which is also known as Cittamatra ("Consciousness Only") is an important philosophical school within Indo-Tibetan Buddhism.

Yoga and tantra

Yoga is often mentioned in company with Tantra. While the two have deep similarities, most traditions distinguish them from one another.
They are similar in that both amount to families of spiritual texts, practices, and lineages with origins in the Indian subcontinent. (Coincidentally, both have been popularized to some extent in the West, with perhaps a shallower understanding of their nature). It should be noted however that for the most part, we are speaking of different families of texts, lineages, etc.
Their differences are variously expressed. Some Hindu commentators see yoga as a process whereby body consciousness is seen as the root cause of bondage, while tantra views the body as a means to understanding, rather than as an obstruction. It must be said that in India, tantra often carries quite negative connotations involving sexual misbehavior and black magic. Nevertheless, most forms of tantra follow more mainstream social mores. The Hatha Yoga Pradipika is generally classified as a Hindu tantric scripture.
Tantra has roots in the first millennium CE, and incorporates much more of a theistic basis. Almost entirely founded on Shiva and Shakti worship, Hindu tantra visualizes the ultimate Brahman as Param Shiva, manifested through Shiva (the passive, masculine force of Lord Shiva) and Shakti (the active, creative feminine force of his consort, variously known as Ma Kali, Durga, Shakti, Parvati and others). It focuses on the kundalini, a three and a half-coiled 'snake' of spiritual energy at the base of the spine that rises through the chakras until union between Shiva and Shakti (also known as samadhi) is achieved. (Some Hindu yoga teachers, however, have adopted these concepts.)
Tantra emphasises mantra (Sanskrit prayers, often to gods, that are repeated), yantra (complex symbols representing gods in various forms through intricate geometric figures), and rituals that range from simple murti (statue representations of deities) or image worship to meditation on a corpse! While tantric texts (see kaularvatantra, mahanirvana tantra) and teachers (e.g. Abhinava Gupta) may seem odd and highly arcane from the point of view of classical yoga, that these incorporate yoga concepts seems clear.
In Tibetan Buddhism, which embraces both, yoga is seen as a synonym for "spiritual practice," while "tantra" refers to a specific category of texts and practices, etc that are roughly analogous to the Hindu ones described above. (The fact that Hindu "yoga" has these things as well may have escaped the attention of classical Tibetan commentators.) In that spirit other Buddhist traditions, such as Theravada, practice a form of "yoga" but reject "tantra."

Ancient Indian Science and technology as described by Michel Danino.

 Ancient Indian Science and technology as described by Michel Danino.