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450 BCE
The four elements: c.450 BC
The Greek philosopher Empedocles, a native of Sicily, introduces a theory which will be accepted in Europe until the 17th century. He states that all matter is made up, in differing proportions, of four elemental substances - earth, air, fire and water. Not until the arrival of a 'sceptical chemist' (the title of a book by Robert Boyle in 1661) is there a serious threat to this Greek theory of the elements. -
420 BCE
Democritus and the atom: c.420 BC
In the late 5th century BC Democritus sets out an interesting theory of elemental physics. Notions of a similar kind have been hinted at by other Greek thinkers, but never so fully elaborated. -
4 BCE
Aristotle's variable atoms: 4th century BC
Aristotle, practical as ever in his determination to get things worked out in detail, proposes a new theory to explain how the four elements of Empedocles and the atoms of Democritus produce the wide range of substances apprehended by our senses. -
3 BCE
Greek science in Alexandria: from the 3rd century BC
Classical Greece has produced a brilliant tradition of theorists, the dreamers of science. Attracted by the intellectual appeal of good theories, they are disinclined to engage in the manual labour of the laboratory where those theories might be tested. Read more: http://www.historyworld.net/wrldhis/PlainTextHistories.asp?historyid=ac20#ixzz4AKVa3Tdz -
Dec 24, 700
Alchemy in Asia: 8th - 10th century
There are two important centres of alchemical experiment in medieval Asia. One is Baghdad under the caliphate, where from the 8th century there is enthusiastic translation and study of Greek scientific texts. Arab alchemists, in their pursuit of synthesized gold, make practical advances in techniques of distillation. And they identify several chemical substances. -
Dec 24, 900
Gunpowder: 10th century
In about 1040 a Chinese manual on warfare is issued under the title Compendium of Military Technology. It is the first document to describe gunpowder. This black powder, formed by pounding a mixture of saltpetre, charcoal and sulphur (a dangerous process if the pounding is overdone), seems to have been developed in the small chemical laboratories attached to the temples of Daoists where research is conducted mainly on the secret of eternal life. -
Dec 24, 1200
Science's siesta: 8th - 15th century
In the profoundly Christian centuries of the European Middle Ages the prevailing mood is not conducive to scientific enquiry. God knows best, and so He should - since He created everything. Where practical knowledge is required, there are ancient authorities whose conclusions are accepted without question - Ptolemy in the field of astronomy, Galen on matters anatomical. -
Van Helmont: 1648
A book is published in Amsterdam in 1648 which can be seen as a definitive turning point between alchemy and chemistry. Entitled Ortus Medicinae (Origin of Medicine), it is the collected papers of Jan Baptista van Helmont, an aristocrat who has lived quietly on his estate near Brussels conducting scientific experiments. -
Robert Boyle: 1661-1666
The experimental methods of modern science are considerably advanced by the work of Robert Boyle during the 1660s. He is skilful at devising experiments to test theories, though an early success is merely a matter of using von Guericke's air pump to create a vacuum in which he can observe the behaviour of falling bodies. -
The phlogiston theory: 18th century
Two natural processes, burning and rusting, particularly intrigue the chemists of the 17th and 18th centuries. A concept is put forward in 1667 in Germany in a book by Johann Joachim Becher.
