The early history of chlorine : papers / by Carl Wilhelm Scheele (1774), C.L. Berthollet (1785), Guyton de Morveau (1787), J.L. Gay-Lussac and L. J. Thenard (1809).

Date:
1905
Catalogue details

Licence: In copyright

Credit: The early history of chlorine : papers / by Carl Wilhelm Scheele (1774), C.L. Berthollet (1785), Guyton de Morveau (1787), J.L. Gay-Lussac and L. J. Thenard (1809). Source: Wellcome Collection.

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    Phosphorus, which is exposed to light in dephlo- gisticated muriatic acid, becomes white and opaque be- fore changing into phosphoric acid; it appears that this state is due to a portion of vital air, which is insufficient to give it the properties of an acid; it is probably thus that phosphorus whitens on the surface when it is pre- served for a long time in water; when it is entirely in this state it could be compared to sulphurous acid relatively to vitriolic acid, only that has not yet sufficient vital air to be sensibly acid. It is probably phosphorus thus com- bined with a portion of vital air which M. de Morveau has called the acidifiable base of phosphorus, which he obtained by exposing phosphoric acid in a crucible to a considerable degree of heat; for the portion of vital air which was least adherent to the acid, has been forced to dissipate itself, and there was bound to remain a com- bination of phosphorus and a little vital air, which is less combustible and less liable to be attacked by nitrous acid i°, because the affinity of the phosphorus for vital air is already satisfied in part, 2°, because the heat which would be disengaged at the commencement, when the combination took place with the greatest force, cannot in this case aid that part of the combination which takes place only through a feeble affinity. It is thus that sulphur is immediately reduced to vitriolic acid if the combustion is vivid; but that, if the combustion is slow, only sul- phurous acid is formed, which then assumes the state of vitriolic acid with some difficulty. It is probable that ordinary phosphoric glass similarily retains a greater or less quantity of vital air. Chemists in general have believed that all the colours of bodies are due to the same principle diversely modi- fied and combined in different proportions. Bergman in particular has attributed them to phlogiston (Mem. sur l’indigo) and he has claimed to prove by ingeni-