Vital air

Lavoisier checked Ptiesdey s work and recognizing that air contains mainly two gases, named one vital air and the other azote (nitrogen), the latter not supporting life. Later, vital air became oxygen, from the abiUty to form acids ox, ie, sharp (taste) 2in.dgen, to form. In 1777, Lavoisier developed the theory of combustion. His ideas became widely estabhshed and were firmly fixed by his textbook, Ixi Traitu Elumentaire de Chemie (2). 

Lebcos-haltung, /. standard of living, -holz, n. lignum vitae, -kraft, /. vital force vitality, -kunde, -lehre, /. biology, -luft, /. (Old Chem.) vital air (oxygen), -luftmesser, m. eudiometer. 

Antoine-Laurent Lavoisier (1743—1794) followed up Priestley s work by making quantitative measurements of the ratio of oxygen to nitrogen in air. At first he named the new gas highly respirable air and later, vital air. Lavoisier is often considered the father of modern chemistry ... 

It is therefore to the vital air [oxygen] of the manganese [pyrolusite], which combines with the marine acid, that the formation of the dephlogisticated marine acid is due. I ought to state that this theory was presented and announced some time ago by M. Lavoisier, and that M. de Fourcroy made use of it in his Elements of Chemistry and Natural History to explain the properties of dephlogisticated marine acid such as they were then known. 

Dephlogisticated marine acid] is manifestly formed by the combination of vital air with marine acids but in it the vital air is deprived of a part of the principle of elasticity, and adheres so feebly to the marine acids that the action of light suffices to disengage it promptly, light having more affinity for its base than marine acid has (4). 

The first three of these phenomena will be sufficiently familiar, but the last involved a more hazardous hypothesis that Lavoisier made explicit only a little later. Hints of the idea that vital air, or as he renamed it, oxygen, was the principle of acidity appear early in his writings. He made a public commitment to that view in the paper published in the Academy Memoires for 1778 that appeared in 1781 General considerations on the nature of... 

As to the real nature of fixed air, Black, in his manuscript notes, says With regard to its origin, when treating of inflammable substances and metals, I shall consider this more completely. I shall now only hint that it is a vital air, changed by some matter, seemingly the principle of inflammability, [that is phlogiston].6 A contemporary of Black, Dr. Leslie, also says, Dr. Black seems to consider fixed air as a particular modification of common air with the principle of inflammability. 0 Black was an adherent of the phlogiston theory until after Lavoisier had published, in 1789, his Elementary... 

In the course of the memoirs that I have communicated to the Academy, I have passed in review the principal phenomena of chemistry. I have insisted upon those which accompany combustion, the calcination of metals, and, in general, all the operations where there is absorption and fixation of air. I have deduced all the explanations from a simple principle. This is that the air pure, the vital air, is composed of a simple principle which is peculiar to it, which forms the base of it, and which I have called prin-cipe oxygine —combined with the material of fire or heat. This principle once admitted, the chief difficulties of chemistry have appeared to vanish and be dissipated, and all phenomena have been explained with astonishing simplicity. 

The composite nature of water held a significant place in Lavoisier s oxygen theory because it accounted for the inflammable air and the vital air produced in the humid calcination of metals. In the calcination of metals using vitriolic acid, Lavoisier knew that the vital air did not come from the vitriolic acid, since the operation did not produce sulphur or sulphurous acid. Water was the only possible source. Lavoisier worked hard, therefore, to prove the compound nature of water, which he presented to the Academy on November 12, 1783. The importance he attached to this project becomes evident, as Daumas and Duveen pointed out, in his careful preparation for a large-scale demonstration. The public enthusiasm for ballooning had induced the Academy to appoint a... 

Berthollet s paper on nitrous acid was reviewed by Cadet and Lavoisier. Since Lavoisier had a strong agenda by this time of establishing vital air as the acid principle, it is not possible to discern Berthollet s voice. Berthollet had apparently obtained fixed alkali and dephlogisticated air by heating pure niter. Since niter was composed of nitrous acid and fixed alkali, this meant that nitrous acid was converted to dephlogisticated air. This conclusion contradicted the experiment in which Priestley had obtained much nitrous acid as well as dephlogisti-... 

I regard sulphur as a combination of phlogiston with a base which is common to it vitriolic acid, I regard vitriolic acid as a combination of this same base with vital air deprived of its elasticity. It appears that sulphurous acid contains proportionately less of the aerial principle than vitriolic acid, less of phlogiston than sulphur the balance which is found between these two principles the base common to vitriolic acid sulphur, is ruptured by heat phlogiston is united more intimately with a part of this base, the aerial principle, which was a third of this part, is combined in parallel with the other part which is abandoned by phlogiston. There results from this two simpler thus more perfect combinations sulphur or the combination of the base of vitriolic acid phlogiston vitriolic acid or the combination of the aerial principle the base common to sulphur vitriolic acid." ... 

The work was of immense importance to the field, but let s note some interesting little flaws that prove that even Lavoisier was not infallible. First, he names vital air as oxygene, which means acid maker. This was reasonable to Lavoisier since combustion of carbon, sulfur, and phosphorus in pure oxygen each produced acids. His oxygen theory of acids was well accepted. This included... 

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