This remark holds with regard to all other distillations. Any quantity of liquor, set to distil in its fluid state, will take much more time to rise in vapours, and pass from the retort into the receiver, than if it be incorporated with some solid body reduced to minute parts, so that the whole shall make a moist powder; and this though the very same degree of fire be applied in both cases. If the matter from which it is proposed to extract Sulphur be such as will melt with the degree of fire necessary to this operation; that is, with a heat which will make the retort but faintly red, it must be mixed with some substance that is not so fusible. Very pure coarse sand, or clean gravel, may be used with success: but absorbent earths are altogether improper for this purpose, because they will unite with the Sulphur. The sulphureous minerals which are most apt to fuse are the cupreous Pyrites, or yellow copper ores: common lead ores are also very fusible. The Pyrites are by this operation deprived of almost all the Sulphur they contain; and consequently little is left behind, but the particles of iron and copper, together with a portion of unmetallic earth, which we shall shew how to separate from these metals, when we come to treat of them. I say that by this operation the Pyrites are deprived of almost all, and not entirely of all their Sulphur; because, this separation being made in close vessels only, there always remains a certain quantity of Sulphur, which adheres so obstinately to the metals, that it would be almost impossible to get it all out, even though a much stronger fire than that directed in the process were applied for this purpose, and though choice had been, as it ought to be, made of such Pyrites, or other sulphureous Minerals as part most easily with their sulphur. Nothing but a very strong fire in the open air is capable of carrying it wholly off, or consuming it entirely. In several places are found great quantities of native Sulphur. The Volcanoes abound with it, and people gather it at the foot of those burning mountains. Several springs of mineral waters also yield Sulphur, and it is sometimes found sublimed to the vaulted roofs of certain wells, and among others in one at Aix-la-Chapelle. The Germans and Italians have large works for extracting Sulphur in quantities out of Pyrites, and other minerals which abound therewith. The process they work by is the same with that here delivered; but with this difference only, that Sulphur being but of small value they do not use so many precautions. They content themselves with putting the sulphureous minerals into large crucibles, or rather earthen cucurbits, which they place in the furnace in such a manner that, when the sulphureous part melts, it runs into vessels filled with water, and is thereby fixed. The Sulphur obtained, either by distillation or by simple fusion, is not always pure.