There is moreover another advantage in not using the sand-bath; which is, that if in the time of the operation you perceive the fire too fierce, you can quickly check it, either by stopping close all the apertures of the furnace, or by drawing out all or part of the lighted coals. This inconvenience is not near so easily remedied when you use the sand-bath; because when once heated it retains its heat very long after the fire is quite extinguished. PROCESS VII. _To decompose Vitriolated Tartar by means of the Phlogiston; or to compose Sulphur by combining the Vitriolic Acid with the Phlogiston._ Take equal parts of Vitriolated Tartar, and very dry Salt of Tartar, separately reduced to powder; add an eighth part of their weight of charcoal-dust; and mix the whole together very accurately. Throw this mixture into a red-hot crucible, placed in a furnace filled with burning coals. Cover it very close, and keep it very hot; till the mixture melt, which may be known by uncovering the crucible from time to time. There will then appear a blueish flame, accompanied with a pungent smell of Sulphur. Take the crucible out of the fire: dissolve its contents in hot water: filter the solution through brown paper supported by a glass funnel: drop into the filtered liquor by little and little any Acid whatever. As you add the acid the liquor will grow more and more turbid, and let fall a grey precipitate. Continue dropping in more Acid till the liquor will yield no more precipitate. Filter it a second time, to separate it from the precipitate: what remains on the filter is a true inflammable Sulphur, which you may either melt or sublime into flowers. _OBSERVATIONS._ All bodies that contain the Vitriolic Acid may contribute, as well as Vitriolated Tartar, to the generation of Sulphur: so that all the neutral salts in which this Acid is a principle, the Alums, Selenites, Gypsums, Vitriols, may be substituted for it in this experiment. All these matters, with the addition of charcoal-dust only, being fused in a crucible, constantly produce Sulphur; because the Vitriolic Acid having a greater affinity with the Phlogiston than with any thing else, will quit its basis, whatever it be, to join with the Phlogiston of the charcoal, and therewith form a Sulphur. The fixed Alkali added thereto helps to promote the fusion of the ingredients, which is necessary for effecting the desired combination. It also serves to unite with the Sulphur, when formed; and thus makes the combination called _Liver of Sulphur_, which prevents the Sulphur from being consumed as soon as formed: for the fixed Alkalis, which are incombustible, hinder Sulphur from burning so easily as it would do if they were not joined with it. They may afterwards be separated from each other, by the means of any Acid whatever.