A New Earth Is Identified

I do not mean the ordinary lead ore that is available in the pharmacies. The stuff I investigated is quite different from that. It is instead the mineral that Axel Fredrik Cronstedt called molybdcena membranacea nitens in his Mineralogy and with which Mr Qvist and others probably made their experiments. 

The results were pubhshed in the Transactions of the Royal Swedish Academy of Sciences [25.1]. 

When we try to follow this description we find that Scheele proceeded systematically and with impressive care. 

The mineral was mixed with arsenic acid (oxidation agent) and heated in a retort. When water had disappeared the temperature was increased. A heavy vapor was formed that was collected in a receptacle as a hquid. It was sulfuric add. 

When the mineral was treated with boiling dilute nitric add, nitrous gases were evolved. After evaporation to dryness the residue on the bottom of the beaker was gray. After five repetitions of the process - treatment with nitric acid and evaporation - a white residue was obtained. This white substance could be subhmed and collected on iron sheets as white or yellowish scales. The white earth could also be prepared by melting molybdcena with saltpeter. Scheele made an important statement from these results I have thus seen an earth that up to now has probably been unknown. 

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