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Period: Sep 30, 1543 to
The Scientific Revolution
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Van Helmont: 1648
Van Helmont weighs out 200 lbs of dried earth, places it in an earthenware container and plants a willow tree weighing 5 lbs. For five years he waters the plant daily. At the end of the experiment the willow tree weighs 169lbs and the earth, when dried, not much less than 200 lbs. Van Helmont concludes, reasonably that the wood, bark and leaves of the tree must be composed of water, which he therefore considers to be the chief constituent of all matter. He is half right - any willow tree is abo -
Robert Boyle: 1661-1666
Boyle's best-known experiment involves a U-shaped glass tube open at one end. Air is trapped in the closed end by a column of mercury. Boyle can show that if the weight of mercury is doubled, the volume of air is halved. The conclusion is the principle known still in Britain and the USA as Boyle's Law - that pressure and volume are inversely proportional for a fixed mass of gas at a constant temperature. Boyle's most famous work has a title perfectly expressing a correct scientific attitude. Th -
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. explaining such changes as the release of a particular substance, present in all materials which are capable of changes of this kind. The theory was developed by George Ernst Stahl, who in a 1702 edition of Becher's work gave the mystery substance the name phlogiston - from the Greek phlogizein, to set aligh -
Demons in the ore: 1742-1751
From the mid-18th century there is rapid acceleration in the discovery of new elements, as chemists improve their analytical methods in the laboratory. These substances are not at first recognized as elements (a concept only firmly established in the 19th century), but in each case it is evident that a previously unidentified material has been isolated.
The only use found for the residue of such ore after roasting is in the making of glass, to which it adds a beautiful blue colour. In about 1735 -
Future Perdiction
Chemistry will describe to us what really happens to the earth and how it was really created
