Factitious airs

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Factitious airs is an archaic term for synthetic gases coined by Robert Boyle around 1670 .

Factitious airs (also factitious air or artificial airs) was a term used in 17th- to early 19th-century pneumatic chemistry for any gas, then called an "elastic fluid",[1] that could be artificially produced from solid or liquid bodies by chemical reaction, fermentation, putrefaction, distillation, dissolution, or heat. The phrase was coined by Robert Boyle around 1670 while isolating what is now recognized as hydrogen (which he termed "inflammable air").[2]

The term was rigorously defined by Henry Cavendish in his landmark 1766 paper Three papers, containing experiments on factitious air. Cavendish described factitious air as "any kind of air which is contained in other bodies in an unelastic state, and is produced from thence by art".[3][4] At the time, these gases were understood to be distinct from ordinary atmospheric air and were rarely obtained in pure form; archaic nomenclature was therefore inconsistent and often applied overlapping or mistaken labels to the same substance.

The study of factitious airs encompassed what are now known as hydrogen ("inflammable air"), carbon dioxide ("fixed air" or "fixible air"), ammonia ("alkaline air" or "volatile alkali"), oxygen ("dephlogisticated air", "vital air", or "oxygene"), nitrous oxide ("dephlogisticated nitrous air"), nitric oxide ("nitrous air"), carbon monoxide ("hydrocarbonate" or "water gas"), methane ("marsh gas" or "carburetted hydrogen"), hydrogen sulfide ("hepatic air"), and several others. These investigations were central to the development of pneumatic chemistry, the refinement and eventual overthrow of phlogiston theory, and the Chemical Revolution led by Antoine Lavoisier. The same body of work also laid the foundation for pneumatic medicine, most notably through the efforts of Thomas Beddoes and James Watt at the Pneumatic Institution in the 1790s, where factitious airs were trialed as treatments for tuberculosis and other conditions.

With the widespread acceptance of Lavoisier’s oxygen theory and the new chemical nomenclature in the late 1780s and 1790s, the archaic term "factitious airs" gradually fell out of use.

Definition

Factitious means "artificial, not natural",[5] so the term means "man-made gases".

An archaic definition from 1747 for the production of factitious air was defined as being caused by: "1- by flow Degrees from Putrefactions and Fermentations of all Kinds; or 2- more expeditiously by some Sorts of chymical Dissolutions of Bodies; or 3- and lastly, almost instantaneously by the Explosion of Gunpowder, and the Mixture or some Kinds of Bodies. Thus, if Paste or Dough with Leaven be placed in an exhausted Receiver, it will, after some Time, by Fermentation, produce a considerable quantity of Air, which will appear very plainly by the Sinking the Quicksilver in the Gage. Thus also any Animal or Vegetable Substance, putrifying in Vacuo, will produce the same Effect."[3]

Therapeutics

Historical Names

References

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