SULPHUR, an inflammable fossil, of which there are two species, viz. com mon natural sulphur, and volcanic natural sulphur. The colour of the natural sul phur is yellow, of different degrees of intensity; it occurs massive, disseminated, and crystallized. The crystals are mid dle sized and small, of which the surface is smooth and splendent. Internally it is intermediate between shining and glist ening. It is soft and frangible. When placed on inflamed coals, it burns with a bluish flame, and emits a pungent suffo cating vapour, and is totally volatilized. It is found in many parts of the world. It occurs commonly in muses, in gypsum, lime-stone, and marl : and in some places, with honey-stone, and bituminous wood. It is often found in veins that traverse primitive rocks; in veins of copper py rites that traverse granite ; in Siberia It is found in the gold mines of Catherineburg, and in the lead glance veins in the Altam mountains. Humboldt mentions a pro vince of Quito, in which he discovered a bed composed of sulphur and quartz, in a mountain of mica slate ; he likewise found great quantities of sulphur in pri mitive porphyry.
The volcanic natural sulphur is yellow, inclining to green : it occurs sometimes corroded ; sometimes as a sublimate in flowers. It is glistening, and its lustre is resinous, inclining to adamantine. It oc curs only in volcanic countries, where it is found in greater or smaller quantity among the lava. Solfatara, in the vicinity of Vesuvius, is one of the most famous repositories of natural volcanic sulphur, and is there collected in considerable quantities for the purposes of commerce. It is found also in Iceland, in Etna, and in the Lapari islands. It occurs likewise in the island of Teneriffe, and in the West India islands ; in Java, and the East In dies. Having thus described this sub stance mineralogicaUy, we turn to it in a chemical view.
Sulphur is a simple undeconipounded combustible substance, which is univer sally diffused in nature ; but most com monly in a state of combination with mi neral, vegetable, or animal matters. It is found in some mineral waters, but in greatest abundance in volcanic countries, where it is a valuable article of commerce. Sulphur, as it is extracted from minerals and purified by art, is a hard, brittle Ab stance, of a yellow colour, which cA be easily reduced to powder. It is always opaque, has a lamellated fracture, and becomes electric by friction. The spe cific gravity, after it is melted, does not exceed 1.99. It has no smell, and very little perceptible taste. When it is rubbed some time it is volatilized, and diffuses a peculiar and slightly foetid odour, by which it is easily distinguished. It leaves on the skin which has been in contact with it a very strong smell, which remains for some hours. It is insoluble in water. Light
has no sensible effect on sulphur. But if a roll of sulphur be held in the hand for a little, it begins to crackle, and at last it breaks to pieces. When a temperature equal to that of boiling water is applied to sulphur, it melts, becomes liquid and transparent, and changes to a brown red colour : but on cooling, if the fusion is not too long continued, it resumes the yellow colour. If it be permitted to cool slowly, it crystallizes into prismatic needles. The crystals are better formed by pouring out part of the liquid sulphur as soon as the surface has become solid. If the heat be continued, it becomes thick and viscid ; and if it be then poured into cold water, it retains its softness, so that it is employ. ed for taking impressions of seals and medals. In this state they are called sulphurs. When sulphur is exposed to heat in close vessels, it is volatilized or sublimed in the form of very fine pow der, known under the name of flowers of sulphur. Sulphur enters into combination with oxygen, azote, hydrogen, carbon, and phosphorus. When sulphur is kept some time in fusion in an open vessel, it assumes a red colour, and becomes viscid. After it is cooled, it retains its red colour, which is owing to the combination of oxy gen in small proportion with the sulphur. In this state it has been denominated the oxide of sulphur.
According to the experiments of Dr. Thomson, the oxide of sulphur, formed bx melting the substance in a deep vessel, s of a dark violet colour, fibrous fracture, and tough consistence ; the specific g•ra vity is 2.3. Another oxide was formed by passing a current of oxymuriatic acid gas through flowers of sulphur. When .sul phur is burnt in the open air, it emits a pale blue flame, with a great white smoke. When these fumes are mix ed with water, it is found to possess acid •properties. This is a combination of sul phur with a greater proportion of oxygen than exists in the oxide, and is called sul phurous acid. But when sulphur is burnt in oxygen gas, a very rapid combustion takes place, with a reddish white flame, and it combines with a greater proportion of oxygen. When the fumes, which are copiously emitted during this combustion, are collected, and mixed with water, it exhibits the properties of an acid, which is the sulphuric acid. Thus it appears, that sulphur combines with oxygen in four different proportions. In two of these, in which the proportions are the smallest, the compounds are denominated oxydes ; but in the two others, in which the pro portion of oxygen is increased, the com pounds are acids, the properties of which will be afterwards noticed.