(375–413 CE). The first iron pillar was the Iron pillar of Delhi, erected at the times of Chandragupta II Vikramaditya. The
Arthashastra of
Kautilya mentions the construction of dams and bridges. The use of
suspension bridges using plaited bamboo and iron chain was visible by about the 4th century. The
stupa, the precursor of the
pagoda and
torii, was constructed by the 3rd century BCE. Rock-cut
step wells in the region date from 200 to 400 CE. During the 1st millennium BCE, the
Vaisheshika school of
atomism was founded. The most important proponent of this school was
Kanada, an
Indian philosopher. The school proposed that
atoms are indivisible and eternal, can neither be created nor destroyed, and that each one possesses its own distinct (individuality). It was further elaborated on by the
Buddhist school of atomism, of which the philosophers
Dharmakirti and
Dignāga in the 7th century CE were the most important proponents. They considered atoms to be point-sized, durationless, and made of energy. By the beginning of the
Common Era glass was being used for ornaments and casing in the region. The
Satavahana period further reveals short cylinders of composite glass, including those displaying a lemon yellow matrix covered with green glass.
Wootz originated in the region before the beginning of the common era. Wootz was exported and traded throughout Europe, China, the Arab world, and became particularly famous in the Middle East, where it became known as
Damascus steel. Archaeological evidence suggests that manufacturing process for Wootz was also in existence in South India before the Christian era. Evidence for using bow-instruments for
carding comes from India (2nd century CE). The mining of
diamonds and its early use as gemstones originated in India.
Golconda served as an important early center for diamond mining and processing. The
Arthashastra also mentions diamond trade in the region. The
Iron pillar of Delhi was erected at the times of
Chandragupta II Vikramaditya (375–413), which stood without rusting for around 2 millennium. The
Rasaratna Samuchaya (800) explains the existence of two types of ores for zinc metal, one of which is ideal for metal extraction while the other is used for medicinal purpose. In the 2nd century, the
Buddhist philosopher
Nagarjuna refined the
Catuskoti form of logic. The Catuskoti is also often glossed
Tetralemma (Greek), which is the name for a largely comparable, but not equatable, 'four corner argument' within the tradition of
Classical logic. The origins of the
spinning wheel are unclear but
South Asia is one of the probable places of its origin. The device certainly reached Europe from India by the 14th century. The cotton gin was invented in
South Asia as a mechanical device known as
charkhi, the "wooden-worm-worked roller". This mechanical device was, in some parts of the region, driven by water power. This cotton gin was used until further innovations were made in form of foot powered gins. Each mission returned with different results on refining sugar. A description of
binary numbers is also found in the works of Pingala. The Indians also developed the use of the law of signs in multiplication. Negative numbers and the subtrahend had been used in
East Asia since the 2nd century BCE, and
South Asian mathematicians were aware of negative numbers by the 7th century CE, and their role in mathematical problems of debt was understood. Although the Indians were not the first to use the subtrahend, they were the first to establish the "law of signs" with regards to the multiplication of positive and negative numbers, which did not appear in East Asian texts until 1299. Mostly consistent and correct rules for working with negative numbers were formulated, and the diffusion of these rules led the Arab intermediaries to pass it on to Europe. and was also in use in ancient India. By the 9th century CE, the
Hindu–Arabic numeral system was transmitted from the Middle East and to the rest of the world. The concept of
0 as a number in decimal system, and not merely a symbol for separation is attributed to India. In India, practical decimal calculations were carried out using zero, which was treated like any other number by the 9th century CE, even in case of division.
Brahmagupta (598–668) was able to find (integral) solutions of
Pell's equation and described
gravity as an attractive force, and used the term "gurutvākarṣaṇam (गुरुत्वाकर्षणम्)]" in Sanskrit to describe it. Conceptual design for a
perpetual motion machine by
Bhaskara II dates to 1150. He described a wheel that he claimed would run forever. The
trigonometric functions of
sine and
versine, from which it was trivial to derive the cosine, were used by the mathematician,
Aryabhata, in the late 5th century. The
calculus theorem now known as "
Rolle's theorem" was stated by mathematician,
Bhāskara II, in the 12th century. —written by August 12, 1602—depicts the defeat of
Baz Bahadur of
Malwa by the
Mughal troops, 1561. The Mughals extensively improved metal weapons and armor used by the armies of India.
Indigo was used as a dye in
South Asia, which was also a major center for its production and processing. The
Indigofera tinctoria variety of Indigo was domesticated in India. The woolen shawls from
Kashmir region find written mention between the 3rd century BCE and the 11th century CE. Crystallized sugar was discovered by the time of the
Gupta Empire, and the earliest reference to candied sugar comes from India.
Jute was also cultivated in India.
Muslin was named after the city where Europeans first encountered it,
Mosul, in what is now
Iraq, but the fabric actually originated from
Dhaka in what is now
Bangladesh. In the 9th century, an
Arab merchant named Sulaiman makes note of the material's origin in
Bengal (known as
Ruhml in
Arabic). Out of these maps, two have been reproduced using a manuscript of
Lokaprakasa, originally compiled by the polymath Ksemendra (
Kashmir, 11th century CE), as a source. == Late Medieval (1206–1526) ==