... or by Art; For in factitious Sal Armoniack we finde the common and the Urinous Salts so well mingled, that both in the open Fire, and in subliming Vessels they rise together as one Salt, which seems in such Vessels irresoluble by Fire alone. For I can shew you Sal Armoniack which after the ninth Sublimation does still retain its compounded Nature. And indeed I scarce know any one Mineral, from which by Fire alone Chymists are wont to sever any Substance simple enough to deserve ... — The Sceptical Chymist • Robert Boyle
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