Ancient Chinese Technology

First Use of Diamond

It has been long thought that man first used diamond in India, around the time of Christ, based on the record of documents from India in the latter half of the first millennium, BC. There certainly did not seem to be any evidence from earlier historical periods, let alone prehistoric times. However, we have uncovered evidence that the neolithic Chinese were using diamonds to polish a special group of ceremonial stone burial axes as early as 2500 BC, placing the earliest known use of diamond two thousand years before the mineral is known to have been used elsewhere.

Early Precision Compound Machines

Distinctive spiral grooves carved on ritual jade rings buried in tombs dating from China’s Spring and Autumn period (771–475 BC) follow a precise mathematical form described by the spiral of Archimedes, 300 years before he lived. I show that the precise drafting would have required a precision compound machine in 550 BC, making it the first machine to precisely interconvert linear and rotational motion by half a millennium, and propose a basic mechanical design relying only upon technologies known to have existed at that time.

Peter J. Lu  |  Harvard University  |  Cambridge, MA 02138 USA |  plu_at_fas.harvard.edu