Editing Timeline of historic inventions (section)

====2nd century====
{{See also|2nd century#Inventions, discoveries, introductions}}
* '''132:''' [[Seismometer]] and [[pendulum]] in [[Han dynasty]] [[China]], built by [[Zhang Heng]]. It is a large metal urn-shaped instrument which employed either a suspended pendulum or [[inverted pendulum]] acting on inertia, like the ground tremors from [[earthquake]]s, to dislodge a metal ball by a lever trip device.<ref>{{cite journal |vauthors=Sleeswyk AW, Sivin N | title=Dragons and toads: the Chinese seismoscope of BC. 132 | year=1983 | journal=[[Chinese Science]] | volume=6 | pages=1–19}}</ref><ref>{{cite book | last = Needham | first = Joseph | title = Science and Civilization in China, Volume 3: Mathematics and the Sciences of the Heavens and the Earth | place = Cambridge | publisher = Cambridge University Press | year = 1959 | pages = 626–635| bibcode = 1959scc3.book.....N}}</ref>
* '''2nd century:''' [[Carding]] in India.<ref name=Baber1>Baber (1996), page 57</ref>