The early history of chlorine / papers by Carl Wilhelm Scheele ... [and others].

  • Scheele, Carl Wilhelm, 1742-1786.
Date:
1897
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Licence: Public Domain Mark

Credit: The early history of chlorine / papers by Carl Wilhelm Scheele ... [and others]. Source: Wellcome Collection.

Provider: This material has been provided by UCL Library Services. The original may be consulted at UCL (University College London)

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    to understand at first whence the manganese has obtained its phlogiston; nothing combustible is added here, and nevertheless the complete dissolution of the manganese can be effected without heat. In fact, there occurs here a phenomenon which proves that phlogiston is certainly present in marine acid—a property which one would have attributed to nitrous acid, since chemists, subse- quent to Stahl, have believed that this principle is required in considerable quantity as one of its constit- uents. That, however, we may now reverse and attri- bute to marine acid. When marine acid stood over manganese in the cold it acquired a dark reddish brown colour (§ 6, a). As man- ganese does not give any colourless solution without uniting with phlogiston, it follows that marine acid can dissolve it without this principle. But such a solution has a blue or a red colour (§ 14, No. 4). The colour is here more brown than red, the reason being that the very finest portions of the manganese, which do not sink so easily, swim in the red solution ; for without these fine particles the solution is red, and red mixed with black makes brown. The manganese has here attached itself so loosely to acidum salts that water can precipitate it, and this precipitate behaves like ordinary manganese. When, now, the mixture of manganese and spiritus salts was set to digest, there arose an effervescence and smell of aqua regis (§ 6, b). In order clearly to apprehend this novelty I took a retort containing a mixture of manganese and acidum salis. In front of the neck I bound a bladder emptied of air,* and set the retort in hot sand. The bladder became distended by the effervescence in the retort. When the acid no longer effervesced, which was an indication of its saturation. T removed the bjadder^ * [Compare Alembic Club Reprint, No. 8, g 30-]