Theory of phlogiston

Scientists throughout the world used this simple process of acid + iron filings = exploding gas (FCj + 4HC1 —> 2FeCl2 + 2Hj) to justify their theory of phlogiston, which states that... 

Lavoisier made many more experiments on combustion, and proved that in every case the component of the atmosphere which he had named oxygen combined with the substance, or with some part of the substance, which was burned. By these experiments the theory of Phlogiston was destroyed and with its destruction, the whole alchemical apparatus of Principles and Elements, Essences and Qualities, Souls and Spirits, disappeared. 

It is interesting to note that Daltons atomic theory had no means of confirming the existence of the atoms it assumed. How ironic that the theory of phlogiston was rejected largely because there was no observable evidence that phlogiston existed How was it, then, that Daltons theory became accepted when there was no direct evidence that atoms existed The answer must surely be simply that it worked so extremely well in providing a rational, and quantitative, organization of chemical constitution. 

This theory of the tria prima which is reiterated and discussed very extensively in numerous treatises of Paracelsus, made a strong appeal to the public of his own and later centuries. It indeed almost completely dominated chemical theory and philosophy until the rise of the theory of phlogiston. It was adopted by the authors of the later works ascribed to Basil Valentine and Johann and Isaac Hollandus, and so long as these works were believed to have been written in the fifteenth century, Paracelsus was naturally supposed to have acquired this concept from the works of those writers. 

Stahl gives Becher full credit for originating the theory of phlogiston. 

The theory of phlogiston did not appeal to all of Stahl s contemporaries. Notably is this true of two of the most popular chemistry teachers of the time, Hermann Boer-haave at Leyden and Friedrich Hoffmann of Berlin. Both of these men accepted the idea of Beclier s predecessors that combustion consisted in the loss of some substance, sulphur (sometimes called phlogiston by Hoffmann), oil (oleum) or pabulum ignis (the food of fire). by Boer-... 

It was the development of the chemistry of gases that contributed chiefly to the overthrow of the theory of phlogiston. Yet the men whose discoveries contributed most definitely to that end were all themselves plilogistonists, with the single exception of Lavoisier, who was himself less a discoverer than a clear interpreter of the results of others. 

The success of Lavoisier s Traitc was enormous, as says Professor Grimaux, the capable biographer of Lavoisier. It was at once translated into foreign languages. From all sides felicitations came to the author who could finally enjoy a complete victory over the old theory of phlogiston. 

The Theory of Phlogiston.—In order to appreciate the enormous mlluence which the discovery of oxygen was destined to exert upon the further progress of chemistry, it is necessary to gain some idea of the views then prevalent a-s to the nature of combustion. 

Slowly, carefully, laboriously, Woehler worked away in the sacred temple of his laboratory If he could only make one of those innumerable substances which until now only the intricate chemical workshop of the living organism had fashionedl What a blow he could strike at this false idea—a blow even more powerful than that which immortal Lavoisier had dealt to the mischievous theory of phlogiston half a century before him As he dreamed and hoped he kept working, watching his test tubes and flasks, his evaporating dishes and condensers. 

Boantza, V , The Phlogistic Role of Heat in the Chemical Revolution and the Origins of Kirwan s Ingenious Modifications. .. Into the Theory of Phlogiston , Annals of Science, 65 (2008), pp. 309-38. 

Appalled by his suffering, I started to babble Anyway it was worth it, that explosion. I advanced my understanding of fire, because I discovered that the theory of phlogiston is nonsense. I saw a sudden expansion of the air. It couldn t be contained when I threw in the saltpeter, so it burst out of the flask. The air burned, but not all the air I felt a draft, a sucking. ... 

Chemistry and the Scientific Revolution. The Theory of Phlogiston. The Earlier Period of Phlogiston. Forerunners of a New Age. The End—and the Beginning. 

Boerhaave consistently pursued an independent course, and in chemistry he made no reference to the theory of phlogiston. He held, however, a similar negative view for he considered that combustible bodies contain a combustible ingredient, not always the same, which he called Humour ond Humanism in Fig ... 

Priestley gave an account of his experiments to Lavoisier who then realised that the theory of phlogiston could not be true. He explained combustion as due to union of the combustible material with this new gas, which evidently now required a new name. At first he called it eminently pure air later he changed the name to oxygen or acid producer (Greek oxus, sharp or acid gennao, I... 

It should be mentioned that even at its height of popularity, there were chemists who were skeptical of the phlogiston theory. Nicolas Lemery (1645-1715), for instance, did not adopt the theory of phlogiston. ... 

The ancient Greeks believed there were only four elements—earth, air, fire, and water. Consequently, air was considered a single gas, and centuries passed before people began to realize that air is, in fact, a mixture of several gases. The story of the discovery of airs components begins with the theory of phlogiston. 

What should have been an obvious flaw with the phlogiston theory is that charcoal and other fuels lose weight when they burn, but metals gain weight when they rust or become a calx. If the theory of phlogiston were correct, these observations would imply that there must be two... 

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