The oldest cereal crops in India are barley, Wheat and Rice. These were followed by Ragi, Kodon, Bajra and Jowar. All the major cereals we see in India were in existence for atleast 2000 years. Maize is the only outlier. It was introduced in India around 1435 AD. Clay impression of maize cob with orderly arrangement of grains was found in Kaundinyapur in Madhya Pradesh around this date.

The earliest written record of maize cultivation is during Aurangzeb’s time. Tax on Makka was collected in Jaipur Pargana in 1689. Oat and Rye are recently introduced cereals in India.

Source: Ancient Grains from India, Kajale MD

Quick read: Rohini is the brightest star on the lunar path and is supposed to have been the favourite wife of Chandra, the moon.

Rohini is one of the 27 nakshatras and is the brightest star in the Taurus constellation.

Chandra had married twenty seven daughters of Daksha, the son of Brahma. But he was partial to Rohini and she shone the brightest when he visited her. Daksha was infuriated by this partiality and cursed that Chandra would lose his brightness. Chandra surrendered to Shiva who then diluted the curse. Shiva ordained that instead of losing the brightness forever, Chandra would wax and wane in a cycle.

Puranic stories such as this, were a good way to pass on scientific information (in this case astronomy) in an oral culture!

Additional Source: Manifestations of Shiva, RK Mutt.

Picture Credit: ISRO Launch Vehicle for Rohini

Bhaskara II (12th cent CE) wrote the first work with full and systematic use of the decimal number system. His writings are a compilation of all achievements in Indian maths till his time. He also made many original contributions which anticipated developments in algebra in Europe by few centuries.

One of his books is Lilavati. Latter legend suggests that he wrote it to console his daughter who was destined to remain unmarried. It is unknown how true this legend is, but some problems in Lilavat are addressed to women, using such feminine vocatives as “dear one” or “beautiful one.”

The book has elegant maths riddles. Here is one. “A fifth part of a swarm of bees came to rest on the flower of Kadamba, a third on the flower of Silinda. Three times the difference between these two numbers flew over a flower of Krutaja, and one bee alone remained in the air, attracted by the perfume of a jasmine in bloom. Tell me, beautiful girl, how many bees were in the swarm?”

Source: University of Connecticut, “Lilavati’s Swarm with Solution”; Britannica

The Baudhayana Sulbasutra (600BCE at the least) first gave a detailed statement of the Pythagoras theorem about the relationship of side lengths in a right angled triangle. On its history, Dr Manjul Bhargava states that the Egyptians who made the pyramids must have known this. Pythagorean triplets were mentioned by Mesopotamians in 1800BCE. The first formulation is in the Sulbasutras. The Chinese were the first to provide a proof (500BCE). Pythagoras’ contribution was to present all of the above in a rigorous manner around 6th cent BCE.

Sulbasutras were concerned with how to make fire altars for yajnas – including very complex ones shaped like the falcon. They thus explored ideas like how to make a square from a circle or rectangle and vice versa, how to make a square which is the sum or difference of two other squares etc. This they did by devising practical rules based on experimentation – ‘sulba’ means a rope or measuring instrument. In the process they accurately calculated the square root of 2 & 3. The Sulbasutra approach to geometric problems was algebraic and this trend continued. Thus Indian maths contributed more to algebra than geometry, unlike the Greeks who developed geometry greatly via Euclid.

Source: Breakthrough Science Society, “Science in Ancient India: Reality vs Myth”

Archaeologists have discovered iron objects at six sites in Tamil Nadu. Nearby charcoal, paddy and ceramic bits have been dated to 1,145–3,345 BCE, or between 3,200 to 5,400 years old. This suggests that the process of extracting, smelting, forging and shaping iron to create tools, weapons and other objects may have developed independently in the Indian subcontinent. Earlier, Gachibowli in Hyderabad had revealed iron from 2000 BCE approximately. The earliest organized iron & steel making began in Turkey dating around 1300 BCE.
Tamil Nadu & South India developed into a great centre of iron & steel. From 1st cent BCE onwards, they developed the famous ‘Wootz’ steel, famed for its ability to be worked into thin blades. It was the raw material for making the world famous ‘Damascus’ swords. Wootz is said to be a mistranslation of the Tamil word ‘urukku’ (alloy) or ‘ukku’ (melt). The North developed its own iron techniques evidenced in the Gupta era rust free iron pillar, now standing near Qutub Minar in Delhi. The image shows the iron objects excavated in Tamil Nadu.
Source: https://www.bbc.com/news/articles/c62e36jm4jro

A ploughed field was discovered at Kalibangan dated 2300-1700CE. The field showed a grid of furrows, with one set, more closely spaced, running east-west, and the other, widely spaced, running north-south. Curiously enough, this pattern bears a remarkable resemblance to modern ploughing in the neighborhood, where two types of cereal are grown in the same field.

No remains of either a plough or a ploughshare or a coulter have, however, been obtained from the excavation. However the existence of a field showing tolerably well-preserved furrows provides concrete evidence for the use of the plough. The material of which the ploughshare or coulter were made and its shape still remain to be known.

Source: https://www.harappa.com/blog/worlds-earliest-known-ploughed-field

Firuz Shah Tughlak gets mixed reviews in history. His cruelty & bigotry is known. He also built the massive canal irrigation system around the Indo-Gangetic doab and the region west of the river Yamuna in the 14th cent CE.
Firuz Shah built upon the existing ideas of water conservation. The earlier Chauhan & Tomar rulers of Delhi also invested in baolis & step wells. The still existing Surajkund reservoir is a testimony to their foresight. Ugresan Baoli is in the busy Connaught Place area. Gujarat, Rajasthan, Karnataka & Haryana are known for their excellent artistic stepwells.
Firuz Shah’s canals provided widespread access to water for agricultural lands in northern India in addition to water for the people. In the 1850s, the British built their canal networks on these medieval structures. These works have been further expanded after independence.
The Wikimedia image by Kumarssp shows a baoli in Ferozhah Kotla, Delhi.
Source: ‘Detailed Study of Irrigation Canal’, Sapan Kumar et al, IRJMETS, Dec2022

Pi is the ratio of the circumference of a circle to its diameter. It has been known for 4000 years. Babylonians (1900BCE) calculated it as 3 or 3.125. Egyptians (1650BCE) calculated it to 3.1605. Archimedes (250BCE) was the first to present detailed calculation of pi as a fraction. The Chinese (5th cent CE) calculated it to 7 decimal places. In India, the Sulbasutras (600BCE) don’t refer to pi but from its calculations, it can be inferred as 3.08. The Jains were the first to explicitly present the value of pi as square root of 10. Later Aryabhatta in the 5th cent CE calculated it upto 4 places and Madhava (14th cent CE) to 11 places. Jain maths flourished 200BCE onwards. The greatest of them was Umasvati (150BCE) who hailed from Kusumpura (near Patna). Aryabhatta (5th cent CE) also belonged to this school. Jain maths had certain peculiarities and different nomenclature. They studied pi & the circle in connection with their cosmology. They knew very large numbers and hence the place value system. They classified maths under ten heads – arithmetic, fractions, geometry, squaring, cubing, raising numbers to higher powers, use of ‘unknown x’, permutations & combinations.

Source: R Sridharan, “Mathematics in Ancient & Medieval India”, Chennai Mathematical Institute

Quick read: High phosphorous content has helped the pillar remain rust free for 1500 years.

Note: Towering at 7 meters tall and weighing a colossal 6 tons, the Delhi Iron Pillar stands as a testament to ancient India’s remarkable metallurgical prowess. Believed to be crafted by the early Gupta kings around the 4th century CE, this structure has remained virtually rust-free for over 1600 years.

Made of 98% wrought iron, its secret lies in the intricate horizontal forge welding technique employed by its creators. This meticulous process resulted in a remarkably pure and dense metal, further protected by a thin layer of iron phosphate. The precise formula for this protective layer was unraveled by Dr. R. Balasubramaniam of IIT Kanpur.

Similar examples of rust-resistant steel have been found at Dhar (13th century CE) and the Konark Sun Temple, suggesting a widespread mastery of this advanced technology in ancient India.

Moreover, a fascinating link exists with the traditional metalworking community of Uttar Pradesh and Madhya Pradesh, the Agarias. Tests conducted in the 1960s revealed that iron produced by the Agarias possessed properties almost identical to the pillar’s metal, highlighting the continuity of this unique knowledge across generations.

Source: “Technology in Ancient India”, a presentation by Michel Danino on academia.edu

Picture Credit: Dennis Jarvis. Wikimedia Commons

The Golden ratio is an irrational number approx. 1.618, represented by the Greek symbol ‘phi’. This ratio is said to represent the building block of aesthetic beauty and is found extensively in nature e.g. body proportions of living beings, growth patterns of plants, insects etc. Researchers opine that the beauty of the Brihadeeshwara temple architecture, made in 1018CE, was due to the extensive use of the golden ratio in its design. The golden ratio emerges from the Fibonacci sequence, where each number (with the exception of the first two) is the sum of the two preceding ones (1, 1, 2, 3, 5, 8, 13…).

Fibonacci (1170-1250) was an Italian mathematician who popularized the Indian numeral system in Europe through his book, Liber Abaci. He is said to have stayed at Bugia on the Berbery coast of Africa, where he came into contact with Hindu mathematicians.

The series named after him was in use in India much before him, as the Brihadeeshwarar temple shows. The series was referred to by many Indians writing on musical metres like Virahanka (9th cent CE), Gopala (1135) & Hemachandra (1150).

Source: Velmurgan& Kalaivanan, “Existence of Golden Ratio in Tanjavur Brihadeeshwarar Temple”, Open Journal of Mathematical Science

Quick read: Its foundation is shorter than an average human.

Note: The Brihadeeswara Temple, built by King Rajaraja Chola between 980-1010 CE, remains a testament to ancient Indian ingenuity. This magnificent structure, defying conventional wisdom, stands tall after a millennium with just a 5-foot foundation. Its secret lies in its groundbreaking construction technique.

The Brihadeeswara Temple does not rely on mortar or binding materials. Instead, it utilizes a remarkable interlocking system known as ‘buzzle technology’. Granite blocks are meticulously carved and fitted together with such precision that the pressure applied at the top prevents individual stones from moving. This eliminates the need for plaster, resulting in a seamless and aesthetically stunning edifice.

Further contributing to its resilience is the innovative foundation. Instead of a solid base, the temple rests on a sand-filled platform. This “sandbox” acts as a flexible cushion, absorbing seismic vibrations and distributing stress evenly. Interestingly, this principle shares similarities with traditional Indian charpoy beds, where tension in the ropes increases with applied weight, providing remarkable stability.

Source: Engineering Performance of the Foundation of Thanjavur Brihadeeswarar Temple, K Arunkumar & K Premlatha, Springer Professional.

Picture Credit: Ramanujam S.R

Indigenous variety of rice has been discovered at Lahuradeva in Eastern UP in the Ganga plains dating back 8000-10000 years ago along with evidence of slash & burn cultivation of rice. But rice doesn’t seem to be a popular crop in the Harappan civilisation. It gained importance only in the late period (2000BCE).

Dr Jennifer Bates, a leading scholar of Harappan archeo-botany suggests that rice had a separate domestication process in South Asia. A mix of ‘wetland’ and ‘dryland’ agriculture of local Oryza sativa indica rice developed in India. The truly ‘wetland’ Chinese rice, Oryza sativa japonica arrived around 2000 BC. It is more productive and became dominant.

Source: What They Ate in Indus Valley, Open Magazine

Visvesvaraya was born near Bengaluru and studied engineering in Pune. He worked in Surat, Bombay, Hyderabad, Aden and Tanzania. In 1909, he was invited to be Chief Engineer of Mysore state. He proposed the Krishna Raja Sagara dam. Though expensive, it was approved by the Mysore Maharaja Krishna Raja Wodeyar. It took 20 years to build was opened in 1931.
He became the Dewan (Prime Minister) of Mysore in 1912 and served the Maharaja. He transformed Mysore into one of the most modern places in India – building industries, universities, power supply, banks etc. He was knighted by the British government & honored with Bharat Ratna by free India.
It is said that on being appointed Diwan, he called his relatives and said that he would accept the appointment only if they swore not to ask for favours. He remains one of the most recognizable figures in Karnataka. Engineer’s day is celebrated in Tanzania and Sri Lanka as well on September 15th honouring his contributions. The image from Wikimedia by Ashwin Kumar is of the majestic Krishna Raja Sagara.

Quick read: India produced pure zinc in 9th CE after perfecting zinc smelting for 1000 years.

Note: Brass is a common alloy of Copper and Zinc. It has been in use for several thousand years. Arthashastra, Ramayana, Mahabharata and other texts refer to zinc and brass as arakutah and ritu or pitala respectively.
However, Brass was produced from copper and Zinc ore and not pure Zinc. Therefore it had low Zinc content.

Pure Zinc was difficult to isolate as it has a low boiling point of 907°C (Iron -2900 deg, Al- 2600 deg, Cu – 2500 deg). It vaporizes when its ore is smelted. Zinc smelting technology was developed in Zawar mines in Rajasthan from 1st Century BCE. Pure Zinc production was perfected in Zawar between 9th to 12th CE through distillation process. This made it possible to produce Brass with higher Zinc concentrations. Modern Zinc making technology developed in Europe only in 18th century.

Hindustan Zinc Limited (HZL) was started as a PSU in Zawar in 1965. Zawar’s history of Zinc production was discovered only in 1980s through excavations jointly sponsored by the company. HZL is now owned by Vedanta and is worth 1.40 Lakh crores in the stock markets.

Source: “Zinc Production in Ancient India”, JS Kharakwal.
Nirupama Kotru, IAS in The Week.

Picture Credit: Remains of an ancient zinc furnace at Zawar from Michel Danino

Jafar, the grand vizier in the Aladdin tale belonged to the Barmakid family, viziers of Abbasid caliphs. The Barmakids were Sanskrit-literate converts from Buddhism, who had studied Indian maths in Kashmir. They sent missions to India that brought the works of Brahmagupta and Aryabhata to Baghdad in 773. Between the 5th-7th cent CE, Indian mathematicians had worked out a system of arithmetic (pati-ganita) & algebra (bija-ganita). This covers mathematics till Standard 10 of today.

A generation later, Persian genius Khwarizmi summarized all the Sanskrit mathematical texts at the House of Wisdom in Baghdad. His name gave us the word “algorithm.” His book Kitab al-Jabr is the basis of our word “algebra.” The original name of the book points to its inspiration “The Compendious Book on Calculating by Completion and Balancing, According to Hindu Calculation”.

Source: William Dalrymple, writing in The Guardian

Quick read: The 27 stars are on the path of movement of the moon.

Yajur Veda gave the first list of 27 nakshatras. These are lunar mansions. Each nakshatra is the prominent star in the path of the moon on the celestial sphere.

Unlike Rig Veda which considered 360 days, the Yajur-Veda considered a lunar year of 354 days and a solar year of 365 days.

Greek influence introduced the 7 day week and 12 Zodiac signs into Indian astronomy. It was codified in the Yavanajataka in the 3rd CE. The seeds of the Zodiac existed though in the Vedas as 12 Adityas.

Picture Credit: CBSE

The Sanskrit word for wheat is Godhuma. The Tamil word is Godumai, remarkably similar. In Punjabi wheat is Kanak, in Bengali it is Gom or Gam and in Marathi it is Gahu.

Source: Origin and History of Godhuma, Patil D. A and Ahirrao Y.A

Rani ki Vav is in Patan, near Mehsana in Gujarat. It is also known for the famous Patan sarees. The stepwell was built by Udayamati in the 11th century in memory of her husband Bhima. It was silted and unknown till 1940s. It is a UNESCO heritage site.
The stepwell is in the shape of an inverted temple and has seven levels. The stairs at each level lead to a circular well at the far end. The stepwell has 500 major sculptures and over a thousand minor sculptures. It has 212 pillars. It also features in our 100 Rs currency note.
Picture Credit: S. R. Ramanujam

Prosody (chandas) was one of the basic studies in ancient India and is a Vedanga (limb of Vedas).

Pingala is the best known prosodist with his work Chandashastra. He adopts the conventional method of metrical analysis of padas or verses. In the last chapter of his work, he introduces a new method which leads to binary numbers & combinatorics.

A metre consists of syllables contained in a foot or a pada with four feet to a stanza. A syllable is of two kinds – laghu (light) or guru (heavy). Normally, any verse is divided into units of three syllables and names assigned to metres on the basis of combination of triplets of syllables. This is the conventional method.

Pingala goes a step further and associates to a syllabic foot, a table called Prastara which consists of rows of laghus & gurus, listed horizontally. He assigns the value 0 to guru and 1 to laghu. He then defines rules for constructing prastaras. Thus he gives equivalence between the binary numbers and their decimal equivalents.

This is the classic binary system which was discovered by Leibniz in the 17th cent. Unfortunately, Pingala’s work on binary numbers did not influence the evolution of maths, remaining confined to the world of music.

Source: R Sridharan, “Mathematics in Ancient & Medieval India”, Chennai Mathematical Institute

At Aranmula, a unique mirror making tradition survives. Here a cast bronze of 33% tin is made without lead. It has a highly reflective property comparable to modern mercury coated glass mirrors. Bronze mirrors have been found elsewhere but they have much less tin (25%) and more lead and thus don’t have great reflection.
Ancient India was a great centre for alloys like bronze & brass. The mastery over bronze is reflected in the dancing girl from the 3rd millenium BCE Indus Valley to the 9th- 10th cent CE Chola Bronze Natarajas made from five metals. Greeks from Alexander’s time also observed that Indians had bronze vessels to store food. This requires making bronze with precise 23% tin which needs to be quickly cooled in oil after mixing. If not, the vessel is brittle and also gets oxidized and cannot store food.
Indians made true brass (>30% zinc content) durable ‘pital’ vessels which were considered family heirlooms till a few decades back. This was because at Zewar in Rajasthan, a technique was developed to distil pure zinc on a commercial scale since 9th cent CE. This zinc making appeared in China & Europe many centuries later. Other parts of the world made brass through cementation that had zinc <30%.
Source: You Tube lecture on Indian metallurgy by Dr Anil Suri, Aalborg, Denmark
Picture Credit: Aranmulakannadi.org

Quick read: Ghati Yantra measured time with a bowl of water.

Indian astronomers had a range of astronomical instruments, easily made by most craftsmen.

Brahmagupta’s magnum opus Brahmasputa Siddhanta describes among others, a water clock (ghati yantra). It is a bowl with a small hole at the bottom, which would sink in exactly 24 minutes (a ghati) if placed over water.

It also describes a gnomon (short stick kept vertically for the study of the motion of its shadow) and a graduated disk or half disk and a scissor like pair acting as compass. Later astronomers like Lalla described more instruments. Brahmagupta (born 598 CE), lived near Mount Abu. He mistakenly rejected Āryabhaṭa’s view of the earth as a rotating sphere. He contributed much to calculations of the mean and true longitudes of planets, conjunctions and problems of lunar and solar eclipses, applying to all these his considerable mathematical skills.

Brahmagupta was one of the major sources of inspiration to Arab astronomers, his works being translated into Arabic called Al-Zij-al-Sindhind in the late 8th cent CE.

Varahamihira was another great astronomer of this period. His Surya Siddanta is considered the fundamental text of Indian astronomy. He also summarized the tenets of Greek astronomy.

Picture Credit: CBSE

Quick read: The Kerala school produced India’s greatest astronomers.

Parameśvara (c. 1362-1455), an author of some thirty works, is the founder of the dṛk system. It improved computations of eclipses and the positions of the planets. Nīlakaṇṭha Somayājī (1444-1545) wrote his landmark Tantrasaṅgraha. It carried out a major revision of the older Indian planetary model for the inferior planets, Budha (Mercury) and Śukra (Venus). It described them as moving in eccentric orbits around the sun, along with Maṅgala or Kuja (Mars), Bṛhaspati or Guru (Jupiter) and Śani (Saturn).

Nīlakaṇṭha preceded Copernicus (1473- 1543), and propounded the heliocentric theory in Europe.

We do not have evidence that Indian heliocentrism directly influenced European advances in the field.

Picture Credit: Kerala Museum

The traditional grinding stone for spices (sil batta in Hindi, ammi kallu in Tamil, shil nora in Bengali) is a set of two heavy stones (sil – flat, batta – cylindrical) used to grind spices. These were very common in Indian kitchens till the mixie made them redundant a generation ago.

These along with a figurine of a woman kneading flower has also been found, showing the continuity of food preparation methods from those times.

Most archeo-botanical research (of food remains in ancient sites) at Harappan sites have focused on cereals. But the discovery of remains of spices like ginger & turmeric, vegetables like eggplants & fruits like mango & jujube on the grinding stones & pottery indicate that Harrapans like Indians today, were fond of curries. One interesting find is remains of ginger & turmeric on the teeth of human & cattle bones. This raises an interesting possibility. Cattle were rummaging through leftover human food in Harappan times too, as they do today. Some unwanted cultural continuity there!

Source: A History of Agriculture in India , DS Randhawa

The circular appam is mentioned in the Perumpanuru, which is a 5th Century Tamil Classical poem. In those times, the present division between Kerala and Tamil Nadu did not exist.

Appam batter is made with and coconut which is also often fermented with toddy overnight. It is thick and soft with a spongy centre and a crisp brown edge.

The basic approach to preparing Appam has led to several varieties of Appam in Kerala – Heating on a metal plate held over boiling water yields Kallappam. Idiappam consists of soft extruded noodles of steamed rice. Steaming in a banana leaf packet with jaggery and jackfruit pulp yields Eleyappam (leaf-appam). Acchappam is made by dipping the batter in a circular patterned mould. Neiappam is a deep fried sweet made with rice and jaggery. Kuzhiyappam or Unniyappam is made by pouring a rice, banana and coconut batter into circular moulds.

Source: Companion to Indian Food, TK Acharya

The ancient roadway links the eastern and western regions of India. It has played a significant role in in the political and economic life of India since the Mauryan period (322 BC–185 BC). The trade route was improved with the road built by Sher Shah Suri. He named it as Sadak-e-Azam (The great road).
The British further improved the road and renamed it Grand Trunk Road. It provided an unbroken line of communication between Calcutta and Peshawar stretching almost over 1,500 miles. Except in case of very wide rivers, the road was permanently bridged throughout.
After Independence, it was abbreviated as NH-1 and NH-2 and named Sher Shah Suri Marg to give due respect to its builder. Sher Shah drove the 2nd Mughal emperor Humayun out of India and ruled from 1540-45. In 1556, Humayun defeated Sher Shah’s successors and reconquered the empire.
The Wikimedia image shows a painting by Ambrose Dudley imagining Sher Shah inspecting the building of the road.
Source: ‘Grand Trunk Road: Continuity & Change’, Dr Nasir Raza Khan, International Journal of Applied Research 2017

Quick Read: APPLE was India’s first communications satellite launched in 1981 and was better known than APPLE Mac.

APPLE is an acronym for Arianne Passenger PayLoad Experiment. It was built in India and was launched from Arianne in France in 1981. Indians above 50 years old knew this APPLE before APPLE Mac (or the IPod or the IPhone).

In the era of telephone and telex, it helped India use space for communication. The first signal telecast live through APPLE was a live dance programme. APPLE also telecast Rabindranath Tagore’s dance drama Chitraganda. APPLE was used for the first two way video-conferencing. It was between Indian scientists and the then Prime Minister Indira Gandhi!

The image is a popular misrepresentation that ISRO had to transport the satellite to the launch centre because of a transport strike, or even that ISRO lacked money for proper transport. In reality, the antennae of the satellite had to be tested in an open field without any magnetic interference. Such test facilities were available only outside India, and were very expensive. ISRO found a solution by hiring a bullock cart for 150 Rs. The location is not launch site, but Peenya in Bangalore.

The average age of the APPLE team was 27 years; and the Director was only 37! APPLE was such a popular satellite that ISRO decided not to repeat the name for any future satellite.

Source: Dr. R.M. Vasagam, APPLE Project Director, ISRO

Picture Credit: ISRO

Kallanai is the earliest irrigation dam in India that continues to be in use. It is also considered among the four oldest dams in the world. It was built by Karikala Chola of the early Cholas, around 150 CE.

The river cauvery bifurcates around Srirangam in Tamil Nadu. The Cauvery branch forms the irrigated delta and is a vital agricultural belt. The Kollidam branch flows straight into the sea and it is a flood carrier. It is barely used for irrigation. Kallanai was used to divert excess flood water into the Kollidam branch through a small connecting river. Thus, agriculture along the cauvery branch was not affected during floods.

This was the first and only hydraulic structure in cauvery till the 19th century. The dam has an unusual curved shape. The top also has notches and slopes which helps in carrying the sediment away from Cauvery and into Kollidam. The British modified the dam substantially in early 19th century.

Source: Tank and anicut irrigation systems engineering analysis, Chitra Krishnan

The second period of Indian astronomy (after the Vedic texts) extended from 3rd cent BCE to 1st cent CE. Jain astronomy (e.g. Surya Prajnapati) developed in this period. It is based on a peculiar model of two sets of 27 nakṣatras, two suns and two moons. It nevertheless resulted in precise calendrical calculations.

Picture Credit: Jambudvipa Map as per Jain Tradition from WikiMedia Commons

In 1881, 70 leaves of a birch bark manuscript in the Grantha language & Sarada script were found at Peshawar. It was incomplete but contained many illustrations on algebra & arithmetic e.g. summing up fractions by equalizing the denominator, arithmetic & geometric progressions, quadratic surds etc. Interestingly it refers to sunya or zero at many places as a dot.

Earlier this manuscript was dated to 12th cent CE but in 2017, the Oxford Bodleian library where it is stored, announced that the revised dating is 3rd-4th cent CE. This makes it the earliest reference to zero as a number, earlier than the inscription at the Chaturbhuj temple, Gwalior dated to 9th cent CE or the sandstone carving unearthed in Cambodia dated to 605CE.

While the use of zero as a placeholder was seen in many cultures, it is in India that the dot evolved to became the symbol that we use. Secondly, it was only in India that zero developed into a number in its own right, as seen in Brahmagupta’s writings (7th cent CE). Indians have talked about zero for long. Panini (6th cent BCE) called it ‘lopa’ (lupt – unseen), Pingala (3rd cent BCE) mentioned it & Buddhists called it sunya (empty, 1st cent CE).

The Arabs literally translated sunya into ‘sifar’ (8th cent CE). Fibonacci (12th cent CE) called it ‘zephyr’ in Latin & Adelard (11th cent CE) ‘siphrae’. The word zero in English comes from the last two terms.

Source: Bodleian library, https://www.glam.ox.ac.uk/

Quick read: The Yuga of Rig Veda was only five years old.

Rig-Veda speaks of a year of 360 days divided into twelve equal parts. It used a five-year yuga. This was perhaps to reconcile the 360 day length with the 365 day solar year. A month was added after five years to catch up. It also metaphorically recorded a solar eclipse. There are also other references to Yuga in Rig Veda that indicate a longer duration, i.e a generation.

The concept of five year Yuga was further elaborated in Vedanga Jyotisha.

Additional Source: Shri P.V Kane

Picture Credit: WikiMedia Commons

Agriculture was established between 7500 BC and 5500 BC in the northwesternmost part of the Indian subcontinent. Earliest evidence is at the ancient site of Mehrgarh which is in Baluchistan. Barley was the dominant crop here and was apparently supplemented with some wheat. The barley found is the well-developed domesticate, six-row barley.

Scholars are divided if the varieties came from West Asia or were indigenous. However, the early barley and wheat in Mehrgarh have predominantly small spherical grains, indicating that varieties adapted to local conditions were developed there. Barley was the predominant crop in the earliest phases of the Harappan civilization. It was gradually supplanted by wheat in the mature phase.

Barley, called Yava, is also the most common agricultural term in Rig Veda and is mentioned more than a dozen times. Rajasthan, Uttar Pradesh and Madhya Pradesh produce 80% of India’s barley

Source: What can Rig Veda tell us on Agriculture, Gyula Wojtilla. https://www.britannica.com/topic/agriculture/The-Indian-subcontinent#ref982313

Namdang Sila Saku is a bridge cut out from a single solid rock. It is over the Namdang River at Sibsagar, Assam. It was constructed by workmen brought from Bengal during the reign of Swargadeo Rudra Singha in 1703. He is considered the most illustrious of the Ahom kings of Assam. It is 60 mtrs in length and 6.5 mtrs in breadth. It has six culverts. It takes the load of traffic passing through NH37.
Source: https://sivasagar.assam.gov.in/tourist-place-detail/334
Picture Credit: https://www.tripuntold.com/assam/sivasagar/namdang-stone-bridge/

Quick read: Its mandapa has 12 pillars each representing a Zodiac sign.

The mandapa of the Sringeri temple is dedicated to the 12 rasis or signs of zodiac as shown in the picture. Some of the pillars of the temple are also aligned to sunrise on the two equinoxes. Studies show that the arrangement of the pillars match the position of Zodiac signs around the year 2000 BCE. Scholars suggest that the pillar arrangement followed a 2000 BCE calendrical device or the structure of Vedic Altar.

In earlier times, temple architecture provided the populace with an interface with astronomy. Many temples show clear astronomical alignments with events such as sunrise at solstices & equinoxes, the most famous being the Sun Temple at Konark.

The more popular interface with the general public was through calendars & panchangs (almanacs) and the prediction of eclipses. Numerous inscriptions record a king’s reward to astronomers who could predict eclipses accurately.

The traditional calendars also require mathematical acumen – for example for calculating the length of a month which are different across months and the same month can have different lengths in different years.

Additional Source: N. Kameswara Rao and Priya Thakur

Picture Credit: N. Kameswara Rao and Priya Thakur

The Hoysala era (1026 CE – 1343 CE) was marked by illustrious achievements in art, architecture, and culture, around Hassan in Karnataka. The famous Hoysala temples include the Chennakesava Temple in Belur, the Hoysaleswara Temple in Halebidu, and the Keshava Temple in Somanathapura. These form the 2023 UNESCO World Heritage Site. Many of these temples are still functioning. One feature of Hoysala temples are pillars so shiny & intricate, a finish that cannot be achieved today without lathes. Historians are divided whether these pillars were handcrafted or made with some kind of primitive lathes. We can only marvel at these pillars.
Source: https://whc.unesco.org/en/list/1670/
Picture Credit: S.R Ramanujam

Amaranth is called Ramdana or Rajgira. It is gluten free and is rich in protein. It is a pseudocereal as its seeds are starchy like cereals, but they are not in the same botanical family of cereals. Rajgira is consumed during fasting days when wheat and rice are avoided. Rajgira chikki is a common panshop item, especially in Mumbai. Amaranth is of Mexican origin.

Quick read; Vedanga Jyotisha is atleast 3000 years old.

Astronomical calendars were needed to keep time for proper conduct of rituals. Vedanga Jyotisha is the first surviving Indian astronomy text. It is one of the six Vedangas(or limbs of Vedas), which are manuals for preservation and interpretation of Vedas. It was composed between 1500 BCE to 1000 BCE.

It identifies the length of the day within a range of 0.5 seconds. It discusses solstices (ayanānta) and equinoxes (viṣuva). It proposes two bridging months (intercalary lunar months or adhikamāsa) to periodically match solar and lunar calendars. This text remains the foundation for India’s traditional luni-solar calendars.

Picture Credit: Dall E render of astronomy as described in Vedanga Jyotisha period.

Quick read: Jai Singh constructed these JantarMantars fusing Indian, Arabic and European astronomy.

In medieval times, the interface with Arab astronomy brought instruments such as the astrolabe to India. Sawai Jai Singh (1688-1743), the Maharaja of Jaipur built the famous and massive yantramantra or Jantar Mantar observatories at Delhi, Jaipur, Ujjain, Varanasi & Mathura. They represent a convergence between Indian, Arabic and European astronomy. These were modelled on the observatory made by Ulug Beg in Samarkand.

Jai Singh collected & studied texts of all three astronomical traditions. He composed his own texts and designed 15 astronomical instruments.

Picture Credit: Rendering of the Jaipur Samrat Yantra, JantarMantar.org

Some ancient south Indian Hindu temples have musical pillars which are made of solid granite. The columns of these musical pillars are often carved from a single piece of granite stone, and they are tuned by means of their length, diameter, and the type of attachment with ceiling and floor. Pillars could be beating pillars where sound is produced by tapping or blowing pillars where sound is produced by blowing wind through holes. These pillars are classified as Shruti which produces basic notes or swaras, Gana produces classical ragas and Laya provides the beats (taal). Experts suggest that the granite used was carefully chosen to be what are called ‘singing rocks’ that have the property of sounding like a bell when struck or rubbing them.
The Wikimedia image by Naveeenkr shows musical pillars at Hampi.
Source: Prasad & Rajavel, ‘Musical Pillars & Singing Rocks’, Stevens Institute of Technology, Hoboken

Quick read: Lothal, near Ahmedabad, has a 4500 year history of household toilets.

Note: The archaeological site of Lothal, near Ahmedabad, offers a fascinating glimpse into ancient sanitation practices. Dating back to 2500 BCE, each house in Lothal boasted well-developed water-borne toilets, connected to extensive drainage systems constructed with burnt clay bricks. Manhole covers and chambers facilitated maintenance, showcasing a sophisticated understanding of sanitation engineering.

Evidence suggests similar, advanced toilet systems existed in other early civilizations around the world. We find sitting-type toilets in Egypt from 2100 BCE and sophisticated public bath-cum-toilets in the Roman Empire.

However, between 500-1500 CE, knowledge of these sophisticated sanitation systems seems to have faded globally. Chamber pots became the norm for the wealthy, while open defecation became unfortunately widespread for the rest. In India, too, the decline of the Indus Valley Civilization coincided with the loss of this vital knowledge, leading to a resurgence of open defecation.

The invention of the modern flushing toilet by John Harington in 1596 resumed good sanitation practices.

Source: “History of Toilets,” Dr Bindeswar Pathak, Founder of Sulabh International

Picture Credit: Bathroom cum Toilet Complex at Lothal. Bernard Gagnon, Wikimedia

Quick read: Andaman has the earliest astronomical object, believed to be 12000 years old.

In every ancient culture, astronomy was born before mathematics: there is, in fact, no need of mathematics to look at the sky.

The first ‘astronomical’ objects, found in the Andamans, belong to the palaeolithic era, some 12,000 years ago. They are probably calendar sticks noting the waxing and waning of the moon by incising daily notches on a wooden stick.

Patterns of rock art in Kashmir, such as a double sun or concentric circles, may indicate depictions of a supernova and meteor showers 7000 years old. Ring-stones in Mohenjo-daro, with rows of small drilled holes could be tracking sunrise at different times of the year. The seal with seven figures in a row could be the Great Bear constellation or Star cluster of Pleiades (Krithika).

Picture Credit: CBSE

Scholars have linked changes in cereal production in Harappan civilization with the 4.2kya event. This climatic shift is broadly described as an abrupt and severe arid phase that began c. 2150 BC and lasted between one and several centuries. This has been linked to the decline of Harappan culture.

In this Late Harappan period, kharif (summer monsoon) crops like rice, sorghum and millets, became more important as compared to the rabi crops of wheat & barley. Millets can withstand arid climate. Harappan sites have a large diversity of millets– foxtail millets, little millets, sawa millets, signal grass millets, finger millets, sorghum, peral/kodo millets. Sorghum remains the most popular millet in India today accounting for 50% of millet production.

Source: Different Strategies in Indus Agriculture, Jennifer Bates & Jungwoo Choi,”

Quick read: Aryabhatta was launched from Soviet Union and was a “made in India” satellite.

Aryabhatta was the first satellite designed and made in India. It was launched from Soviet Union in 1975.

Āryabhaṭa I (born 476 CE), worked near present day Patna. He wrote Āryabhaṭīya. The treatise discussed units of time and features of the celestial sphere.

He estimated the diameter of earth within 12% of actual. His diameters for the planets and the sun are however much too small.

It described the earth as a rotating sphere hanging in space, and produced a table of the planets’ mean positions. Āryabhaṭa also gave a correct explanation for both lunar and solar eclipses.

Bhaskara 1 and 2 were the first two remote sensing satellites. Bhāskara I (b. 600 CE) provided a very useful elucidation of Āryabhaṭa’s astronomy, besides improved calculation methods. Bhāskara II (b. 1114), better known as Bhāskarāchārya, in addition to his astronomical contributions, was the first to explore the full and systematic use of the decimal number system.

Picture Credit: ISRO

Quick Read: Cowasjee’s nose was fixed through plastic surgery.

Note: In the brutal Anglo-Mysore War in 1792, Cowasjee, a bullock cart driver for the British army, endured a horrific ordeal. He was captured by Tipu Sultan’s forces and his nose and one hand were cut off. However, near Pune, a remarkable event unfolded for Cowasjee. A member of the brickmaker caste, using an innovative technique, reconstructed Cowasjee’s nose using a flap of skin from his forehead. This groundbreaking procedure, common in India at the time, attracted the attention of British medics who documented it in the “Gentleman’s Magazine” of 1794.

This detailed account sparked the interest of surgeon JC Carpue, who meticulously studied the technique and eventually practiced it on cadavers. In 1814, he successfully performed the first documented rhinoplasty in Europe on an English Captain, drawing inspiration from Cowasjee’s experience.

The first reference to plastic surgery is in the Sushruta Samhita two millenia ago. Sushruta (6th cent BCE) can be regarded as the father of surgical sciences (shalya tantra).

Source: Gentleman’s Magazine, October 1794.
Aspects of the History of Plastic Surgery since 16th century, JP Bennett
Britannica.com

Picture Credit: The image is an engraving of the procedure. Welcome Library.

Rig Veda refers to Apupa as an offering to Indra. Barley was fried and consumed in the form of cakes dipped in ghee or as sweet cakes called Apupa. They were fashioned out of the flour, boiled in water or fried in ghee and then dipped in honey. Grhtavantam (meaning cooked in ghee) is another term used for Apupa in Rig Veda.

The Bengali sweet Pua and Malpua preserve both the name and essentials of this preparation. Apupa continues to be mentioned in ancient literature including Panini (500 BC).

Source: Companion to Indian Food, TK Acharya

The number system includes numerals 1-9 and zero, place value on base 10 and decimals. This package of ideas, indisputably from India, is followed by every person who learns basic maths. Ancient Greeks, Romans & Egyptians did not use place value. Babylonians and Chinese used a base of 60 & Mayans used a base of 20. Rig Veda first expresses numbers in words, using place value with base 10. By the Kushan period (2nd CE), place value system along with use of zero was well known – a common metaphor was that a woman could be a mother, daughter or a wife. Similarly a number may mean differently depending on its place.

A Syrian bishop Severus Sebokth (7th cent CE) cautions the Greeks not to be too proud because Indians may be better at maths. From 8th Century onwards Arabs popularized the number system. Arabs came to India to learn the system and one great name Ibn Sina (Avicenna, 11th cent CE) claims to have learnt it from an Indian vegetable seller, so common was it in India then.

Source: Alok Kumar, “Ancient Hindu Science.”

Panini (~6th cent BCE) is known for systematizing Sanskrit grammar and was the father of linguistics. He also identified an approach which was adopted by other branches of Indian knowledge systems, including Maths. This is similar to Euclid’s approach. He stated axioms (obvious truths) and then deduced theorems (specific rules) from them.

Panini stated that while you go to a potter for a pot, you don’t go to a grammarian for a word. The grammarian only explains the language which is created as part of social usage. He thus devised rules to explain the language – these were algorithmic (how roots combine into words), recursive (describe metres used ) & symbolic (words broken into syllables that stand for sounds). Nothing was supposed to be axiomatic – a theory explains a given problem, not all problems.

The same approach was taken up by Indian mathematicians. They emphasized procedures & rules over proofs. Not that proofs (upapattis) were not presented but they were done in the bhasyas (commentaries) and not in the sutras. That’s why some historians are reluctant to give full credit to ancient Indian maths saying they lack rigour of modern maths.

Source: Prof MD Srinivas, series of lectures on ancient Indian maths at IIT Bombay, available on you tube.

Quick Read: Tankai refers to a method of stitching planks together instead of nailing them.

Note: The Tankai method, a remarkable Indian shipbuilding technique, utilized stitching instead of nails to seamlessly bind wooden planks together. From its Hindi meaning “to put a stitch,” this ancient ingenuity resulted in flexible hulls. These agile vessels, ranging from 3-ton catamarans to 650-ton behemoths, dwarfed contemporary European ships and effortlessly navigated challenging waters.

Stitched hulls possessed unique resilience, handling rough seas and monsoons better than their European counterparts nailed rigidly together. This flexibility also proved advantageous in negotiating treacherous shoals. Stitched ships were dominant until the 15th century when the need for mounting heavy cannons on ships led to a shift towards rigid, nail-based construction in Europe.

India’s maritime prowess has deep roots. The Harappan civilization, flourishing around 3300-1300 BCE, constructed the world’s first known dry dock at Lothal. Evidence suggests they used flat-bottomed reed boats, a tradition still alive today.

The Indian Navy is currently recreating a 5th-century stitched ship based on historical drawings. This vessel is destined to set sail for Bali in 2025, showcasing the enduring legacy of the Tankai method.

Source: “Ship Building – Historical Perspective”, Admiral Sunil Lunba.

Picture Credit: 5th Century Ajanta painting redrawn by Radhakumud Mukherjee

Quick read: Indus-Saraswati civilization had a remarkably consistent system of weight measures.

Note: The Harappan civilization, flourishing around 3300-1300 BCE, employed a remarkable standardized weight system using cubic stones. This ingenious system was based on a binary progression for smaller weights (1, 2, 4, 8, 16, 32), transitioning to a decimal multiples for larger ones. 32 rattis was the weight of the most commonly found coins. Notably, this system extended beyond trade, suggesting its use in other measurements as well.

This impressive uniformity spanned all Indus Valley sites, highlighting the civilization’s interconnectedness and organizational prowess. The system’s influence endured for centuries, impacting later kingdoms of the Gangetic Plain (300 BCE) and finding mention in texts like Arthasastra and Manusmriti.

Even today, echoes of this ancient ingenuity resonate in India. Gold is still traditionally measured in “tolas,” and “ser” was a common weight unit until recent times. Despite their continued use, the original names of these weights remain veiled by the yet-undeciphered Harappan script.

Source: “Metrology & Linear Measurements” by Michel Danino in the History of India Series on Protohistoric Foundations.

Picture Credit: A set of weights excavated at Dholavira. Michel Danino.

The grand Anaikut also known as Kallanai is an ancient dam built on the Cauvery river in the State of Tamil Nadu. It was built by the Chola king, Karikalan, around the first century CE. It is considered one of the oldest water diversion or water regulator structures in the world, still in use.
The Kallanai is a massive dam of unhewn stone 329 metres long and 20 metres wide across the mainstream of Cauvery. The purpose of the dam was to maintain higher flow in Cauvery river and to divert floodwaters into the Kollidam river. The dam is still in excellent condition and served as a model to later engineers. Sir Arthur Cotton who built the 19th Century dam across the Kollidam also acknowledged the usefulness of Kallanai. The area irrigated by the ancient irrigation network of which the dam was the centrepiece was 69,000 acres. By the early 20th century, the irrigated area had been increased to about one million acres. The Wikimedia image of the dam is by Beckamrajeev.
Source: Rajya Sabha proceedings, 7 Sept 2007; Question by Shri Tiruchi Siva, DMK

Madhava of Sangamgrama (born 1340CE) pioneered a school of mathematics which flourished in a small region of Kerala’s Thrissur district for a couple of centuries at least. The other great scholars from this school are Nilakantha Somayaji & Jyesthadeva.

Madhava demonstrated a deep understanding of the properties of infinite series now associated with calculus. These were later discovered in Europe like the series named after Taylor, Newton, Gregory, Leibniz etc, almost 300 years later. For a long time, historians believed that Indian maths stagnated after Bhaskara II (12th cent CE). This was largely because they were looking for Sanskrit texts while after 1200CE a lot of maths was being recorded in regional languages.

Around 1950, the translation of Jyesthadeva’s Yuktibhasa, a Malayalam text composed around 1520 CE, changed this perception and brought Madhava’s work to light. Yuktibhasa is unique as it is the first Indian maths text to state precise propositions along with their proofs. Historians have often contended that Indian mathematicians were empirical in their approach and did not bother with proofs.

Source: R Sridharan, “Mathematics in Ancient & Medieval India”, Chennai Mathematical Institute

Quick read: Tamil Nadu produced wootz steel with a mixture of iron ore, charcoal and glass.

Note: Wootz steel, once a marvel of the ancient world, captivated with its ability to be forged into exceptionally thin, yet incredibly strong blades. Fashioned into swords and weapons, particularly in Damascus, it earned the legendary status of “Damascus swords” renowned for their razor-sharp edges and remarkable toughness. This marvel, sadly, faded from prominence in the 19th century CE.

Early British experts, upon encountering wootz steel, declared it surpassed any steel from elsewhere in the world. Its intricate crafting involved sealing a mixture of iron ore, charcoal, and glass within crucibles and heating them intensely in furnaces. Evidence suggests its earliest development occurred in Tamil Nadu around 1st century BCE, later spreading across South India and even reaching Sri Lanka.

Beyond its Indian origins, wootz steel transcended borders, known in the Mediterranean region as Hinduwani or Telin (Telangana). Interestingly, the name “wootz” itself is believed to be a misinterpretation of the Tamil word ‘urukku’ (alloy) or ‘ukku’ (melt), emphasizing its inherent nature of combining elements to create something extraordinary.

Source: “Technology in Ancient India”, a presentation by Michel Danino. academia.edu

Picture Credit: Weapons made of Damascus steel. Michel Danino

Sawai Jai Singh created the planned city of Jaipur in early 18th cent CE. Sawai Pratap Singh added the Hawa Mahal in 1799. Hawa Mahal is shaped like Krishna’s crown as Pratap Singh was a devotee of Krishna. It is 87 feet high and has 953 ornate louvered windows (jharokas). Few realize that what you see from the street is essentially the rear of the building. The purpose was to allow the royal ladies to enjoy everyday street scenes without being seen. The building created a cool microclimate for the ladies in hot Jaipur. The orientation of the building is on the east-west axis in the direction of wind flow. The wind enters the palace from the west through open grounds and picks up moisture from the water body placed in the courtyard through convection currents. The moisture-laden wind then moves towards the 953 jharokhas and cools the air down via the Venturi effect – air flows through a constricted passage, increasing the wind velocity while dropping the pressure. Hawa Mahal literally means ‘palace of wind’.
The Wikimedia image of Hawa Mahal is by Marcin Bialek.
Source: Hawa
Mahal: How India’s ‘palace of winds’ was ahead of its time | CNN

Quick read: The floral and colorful calico threatened European fabrics and was therefore banned.

Note: Calico, a humble plain-woven cloth crafted from unbleached cotton, carries a history as rich as its fabric. Born in Kozhikode (Calicut), Kerala, its name reflects its origin. Later, Chintz emerged, a vibrant form of Calico adorned with floral and colorful patterns. Introduced to Europe by Portuguese and Dutch traders, it sparked the “Calico craze,” a phenomenon that threatened European textile industries, ultimately leading to bans.

However, this episode only scratched the surface of India’s ancient and enduring textile tradition. Evidence suggests cotton and silk production thrived as early as the Harappan civilization, with finds like terracotta spindle whorls and dyed cotton fragments. References to “karpasa” (cotton) in the Vedas and textile depictions in Ajanta paintings further solidify this legacy.

From the Roman Empire onwards, India served as a major exporter of textiles, both cotton and silk. Fragments of Gujarati cotton unearthed in Egyptian tombs dating back to the 5th century CE stand as silent testaments to this thriving trade.

Source: “Technology in Ancient India”, a presentation by Michel Danino on academia.edu.

Picture Credit: Chintz from Kerala from early 18th cent CE. Michel Danino

Researchers led by Prof Vasant Shinde have discovered plates and ovens that resemble modern-day tandoors in Rakhigarhi. According to Shinde, a lot of modern-day Indian cuisine, especially those found locally in Haryana, like tandoori chicken or rotis, were being prepared back then in the Indus Valley. “Everything we eat now in modern times was also being eaten back then,” says Shinde.

It is not just the remains of food that tell us what they consumed, Shinde says, but also the types of crockery that were used. “We have found remains of plates in Punjab and Haryana for instance. But for that same period, we find bowls in Gujarat. It indicates that more rotis were eaten in the northern region, while in Gujarat, liquid (or porridge-like) food consisting of sorghum and millets (discovered at these sites) were being consumed.” The continuity of Indian culture is staggering.

Source: What They Ate in Indus Valley, Open Magazine

Quick read: Covid tikah is a carryover from small pox language.

Note: Long before the discovery of vaccination in the late 18th century, a practice known as inoculation or variolation offered some protection against the dreaded smallpox. While this technique gained attention in Europe only in the 18th century, it had been widely practiced in India, China, and the Caucasus for centuries earlier.

In India, the method, called “tikah” by the natives, involved introducing pus from a mature smallpox pustule into a healthy individual, typically through a prick on the forehead. This mild exposure triggered a controlled infection, granting partial immunity to future outbreaks.

Historical records like an East India Company report from 1731 confirm this practice’s longevity. It states that “inoculation… has been known in the kingdom of Bengal about 150 years,” placing its origins in India well before the 18th century. Moreover, another report from 1767 describes specialized Brahmin communities traveling in groups to perform inoculations during outbreaks.

British also condescendingly observed that ignorance and barbarism can also produce valuable improvements. Under British rule, these techniques gradually died out.

Source: “Indian Science & Technology in the Eighteenth Century”, Dharampal.

Picture Credit: The Wikimedia image is of anti cholera inoculation camp at Kolkata in 1894.

Aryabhata used the terms ‘ardha-jya’ (half chord) and ‘jya-ardha’ (chord half). He abbreviated the terms to ‘jya’ (chord). From jya the Arabs phonetically derived jiba, omitting vowels as they usually do. It was written as ‘jb’. The word ‘jiba,’ is otherwise meaningless in Arabic.

Later writers who came across the word ‘jb’ substituted it with ‘jaib,’ which contains the same letters, and is a good Arabic word meaning cove or bay. Gherardo of Cremona (1150CE), when he made his translations from the Arabic, replaced the Arabic ‘jaib’ by its Latin equivalent, ‘sinus’ which means cove or bay. From this translation comes the trigonometric term ‘sine’.

Source: Amartya Sen, “Identity & Violence.”

Mauryan polish describes one of the famous characteristics of architecture and sculptures of the Maurya Empire in India (325 to 185 BCE). It gives a very smooth and shiny surface to the stone material, generally of sandstone or granite. Mauryan polish is found especially in the Ashoka Pillars (including our national emblem) as well as in some constructions like the Barabar Caves.
The technique became lost after the fall of Mauryas. According to the archaeologist John Marshall: the “extraordinary precision and accuracy which characterizes all Mauryan works, and which has never, we venture to say, been surpassed even by the finest workmanship on Athenian buildings.”
It is not clear as to how this polish was achieved. The Didarganj Yakshi, sometimes called the ‘Indian Mona Lisa’ for its stunning beauty, is the best example of Mauryan polish. Historians debate whether it was made in the Mauryan period or later, but the polish is distinctively Mauryan.
Source: Wikipedia
Picture Credit: S. R Ramanujam

In defining God, Indians talked about the Nirguna-rupa (formless) leading to the concept of neti-neti (not this, not that) and sunya (empty). Also in contrast, they visualized a saguna-rupa (with form) and started assigning qualities to God. They concluded that such qualities have to be Ananta (infinite), which incidentally became a name for God. This explains the obsession with very large numbers in ancient Indian maths, unlike in other cultures.

The Shanti Mantra of the Isha Upanishad says,

“oṃ pūrṇam adaḥ pūrṇam idam
pūrṇāt pūrṇam udacyate,
pūrṇasya pūrṇam ādāya
pūrṇam evāvaśiṣyate”

“The world there is full, the world here is full.
Fullness from fullness proceeds
After taking fully from the full,
It still remains completely full”

Source: Alok Kumar, “Ancient Hindu Science”.