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40,000 BCE
Early Metallurgy
The earliest recorded metal employed by humans seems to be gold which can be found free or "native". Small amounts of natural gold have been found in Spanish caves used during the late Paleolithic period, c. 40,000 BC. -
6000 BCE
Bronze Age
Certain metals can be recovered from their ores by simply heating the rocks in a fire: notably tin, lead and (at a higher temperature) copper, a process known as smelting. The first evidence of this extractive metallurgy dates from the 5th and 6th millennium BC, and was found in the archaeological sites of Majdanpek, Yarmovac and Plocnik, all three in Serbia. -
1200 BCE
Iron Age
The extraction of iron from its ore into a workable metal is much more difficult than copper or tin. It appears to have been invented by the Hittites in about 1200 BC, beginning the Iron Age. The secret of extracting and working iron was a key factor in the success of the Philistines. -
200 BCE
Medieval alchemy
Alchemy is defined by the Hermetic quest for the philosopher's stone, the study of which is steeped in symbolic mysticism, and differs greatly from modern science. Alchemists toiled to make transformations on an esoteric (spiritual) and/or exoteric (practical) level.[17] It was the protoscientific, exoteric aspects of alchemy that contributed heavily to the evolution of chemistry in Greco-Roman Egypt, the Islamic Golden Age, and then in Europe -
420
Ancient World
Around 420 BC, Empedocles stated that all matter is made up of four elemental substances—earth, fire, air and water. The early theory of atomism can be traced back to ancient Greece and ancient India -
Dec 24, 1556
17th and 18th centuries: Early chemistry
Practical attempts to improve the refining of ores and their extraction to smelt metals was an important source of information for early chemists in the 16th century, among them Georg Agricola (1494–1555), who published his great work De re metallica in 1556. -
Development and dismantling of phlogiston
In 1702, German chemist Georg Stahl coined the name "phlogiston" for the substance believed to be released in the process of burning. Around 1735, Swedish chemist Georg Brandt analyzed a dark blue pigment found in copper ore. Brandt demonstrated that the pigment contained a new element, later named cobalt. -
Volta and the Voltaic Pile
Italian physicist Alessandro Volta constructed a device for accumulating a large charge by a series of inductions and groundings. He investigated the 1780s discovery "animal electricity" by Luigi Galvani, and found that the electric current was generated from the contact of dissimilar metals, and that the frog leg was only acting as a detector. Volta demonstrated in 1794 that when two metals and brine-soaked cloth or cardboard are arranged in a circuit they produce an electric current. -
Molecular biology and biochemistry
By the mid 20th century, in principle, the integration of physics and chemistry was extensive, with chemical properties explained as the result of the electronic structure of the atom; Linus Pauling's book on The Nature of the Chemical Bond used the principles of quantum mechanics to deduce bond angles in ever-more complicated molecules. -
Chemical industry
The later part of the nineteenth century saw a huge increase in the exploitation of petroleum extracted from the earth for the production of a host of chemicals and largely replaced the use of whale oil, coal tar and naval stores used previously.
