COMBUSTIBLE BODIES, DESTITUTE OF

METALLIC PROPERTIES.

SULPHUR.

PART XI.

SECT. I.

NATURAL HISTORY OF SULPHUR.

SULPHUR, which is also known by the name of brimstone, is the only simple combustible substance which nature offers pure and in abundance. It was the first known of all. It was on this substance that the ingenious Stahl most particularly established his theory of phlogiston, which has governed the schools during a century. In general, sulphur, even considered as a principal subject in chemistry, has been at all times one of those which have participated the most in the different changes which the science has experienced, and concerning which philosophers have been more particularly employed. Sulphur is consequently a body whose combinations are the most numerous, and, at present, the best understood.

It is found abundantly in the earth, and exists externally in depositions, in sublimed incrustations, and on the surface of certain waters, principally near burning volcanoes. It is found combined with many metals. It exists in vegetable substances, and has lately been discovered by Mr. Carlisle in the albumen of eggs.*

Sulphur in the mineral kingdom is either in a loose powder, or compact and crystallized; and then either detached or in veins. It is found in the greatest plenty in

* Nicholson's Journal, August, 1801, p. 178.

the neighbourhood of volcanoes or pseudo-volcanoes, whether modern or extinct, as at Solfatara, &c. and is deposited as a crust on stones contiguous to them, either crystallized or amorphous. It is frequently met with in mineral waters, and in caverns adjacent to volcanoes; sometimes also in coal-mines. It is found in combination with most of the metals. When united to iron it forms the mineral called martial pyrites, or sulphur pyrites. All the ores known by the name of pyrites, of which there are a vast variety, are combinations of sulphur with different metals; and hence the names of copper, tin, arsenical, &c. pyrites. It exists likewise in combination with alumine and lime; it then constitutes different kinds of schistus, or alum ores.

It occurs commonly in masses in gypsum and marls. It is sometimes found in veins that traverse primitive rocks. It occurs also in nests in lime-stone. Very lately the celebrated and enterprising Prussian traveller Von Humboldt has discovered a bed composed of sulphur and quartz, in a mountain of micaceous slate.*

Sulphur is found in Europe, at Baaden in Austria, at Lauenstein in Hanover, at Artern in Thuringia, Schwartzwalde in Swabia, at Jura in Switzerland, Lothringen in France, in the mountains of Grenada, Andalusia, and Conil, near Cadiz, in Spain.

What is called by mineralogists volcanic sulphur occurs only in volcanic countries; where it is found in greater or smaller quantity amongst laya, Solfatara, in the vicinity of Vesuvius, &c.

PHYSICAL PROPERTIES OF SULPHUR.

Sulphur is a combustible, dry, and exceedingly brittle body, of a pale lemon-yellow colour. Its specific gravity is 1.990. It is destitute of odour, except when rubbed or heated. It is of a peculiar faint taste. It frequently crystallizes in entire or truncated octahedra, or in needles. If a piece of sulphur of a considerable size be very gently heated; as for example, by holding it in the hand and squeezing it firmly; it breaks to pieces with a crackling noise. It is a non-conductor of electricity, and hence it becomes electric by friction. When heated, it first softens

VOL. I.

* Annales du Museum National.

23

before it melts, and its fusion commences at 184° Fahr.; at 289° it becomes volatilized, and takes fire at 302°. In the beginning of fusion it is very fluid, but by continuing the heat it grows tough, and its colour changes to a reddish brown. If in this condition it be poured into water, it remains as soft as wax, and yields to any impression. In time, however, it hardens again, and recovers its former consistence.

It unites with most of the earths and with all alkalies, with muriatic acid, and becomes soluble, when thus combined, in water. It unites to most of the metals, and renders them brittle and fusible. It is soluble in oils; water takes up a minute quantity, as does ardent spirit and ether by means of heat. It dissolves in hydrogen gas, and unites to phosphorus by fusion.

Sulphur, like all combustible bodies, burns in proportion to the quantity of oxygen which combines with it.

If melted sulphur be exposed in the open air to an increase of heat, it takes fire, and burns with a blue flame and suffocating vapour. The result of this combustion is sulphureous acid. According to the slow or rapid combustion, it absorbs different quantities of oxygen, and the produced acid differs in its properties. Sulphur heated in a close vessel sublimes without alteration. It is not changed by exposure to air. It is attacked by the nitric acid when poured on it in its fused state.

METHOD OF OBTAINING SULPHUR.

A prodigious quantity of sulphur is obtained from Solfatara, in Italy. This volcanic country every where exhibits marks of the agency of subterraneous fires: almost all the ground is bare and white; and is every where sensibly warmer than the atmosphere, in the greatest heat of summer; so that the feet of persons walking there are burnt through their shoes. It is impossible not to observe the sulphur; for a sulphureous vapour which rises through different apertures is every where perceptible, and gives reason to believe that there is a subterraneous fire underneath from which that vapour proceeds.

From pyrites sulphur is extracted in the large way by the following process:

Pyrites is broken into small pieces, and put into large earthen tubes, which are exposed to the heat of a furnace. A square vessel of cast-iron, containing water, is connected as a receiver with the tube in the furnace. The action of the fire proceeds, and the sulphur being thus melted is gradually accumulated on the water in the receiver. It is then removed from this receiver, and melted in large iron ladles; in consequence of which, the earthy parts with which it was contaminated are made to subside to the bottom of the ladle, leaving the purified sulphur above. It is then again melted, and suffered to cool gradually, in order to free it from the rest of the impurities. It is then tolerably pure, and constitutes the sulphur we meet with in large masses or lumps in the market.

In order to form it into rolls, it is again melted and poured into cylindrical wooden moulds: in these it takes the form in which we usually see it in commerce, as roll sulphur.

Flowers of sulphur, as they are called, are formed by subliming purified sulphur with a gentle heat in close rooms, where the sublimed sulphur is collected; though the article met with in general, under that name, is nothing but sulphur finely powdered.

METHOD OF PURIFYING SULPHUR.

Take one part of flowers of sulphur, boil it in twenty parts of distilled water in a glass vessel for about a quarter of an hour; let the sulphur subside, decant the water: and then wash the sulphur repeatedly in distilled water; having done this, pour over it three parts of pure nitro-muriatic acid, diluted with one part of distilled water; boil it again in a glass vessel for about a quarter of an hour, decant the acid, and wash the sulphur in distilled water till the fluid passes tasteless, or till it does not change the blue colour of tincture of cabbage, or litmus. The sulphur thus carefully treated is PURE SULPHUR, fit for philosophical experiments.

We shall now endeavour to prove some of the before stated properties of sulphur.

SECT. II.

EXPERIMENTAL PROOFS OF THE PROPERTIES OF SULPHUR.

EXPERIMENT I.

Slow combustion of sulphur.

PUT some threads previously dipped in 'sulphur into a cup or other vessel floating on water. Set fire to the threads, and cover the whole with an inverted glass receiver. The threads will continue to burn for some time, and the whole receiver will become filled with a dense white vapour. The water will ascend into the receiver. The whole is then to be left till the vessel is become again transparent. If the water be now examined, it will have a suffocating odour and taste. It will turn the blue colour of litmus paper red, and exhibit all the other signs that an acid has been formed,

RATIONALE...The sulphur, being a simple body, has at an elevated temperature a great affinity to oxygen; it therefore attracts it from the atmospheric air, and thus becomes converted, by slow combustion, into sulphureous acid gas, which is absorbed by water. The volume of air within the receiver being diminished, is the cause of the ascent of the fluid,

This experiment may perhaps be more conveniently performed by covering burning sulphur contained in a crucible with a large receiver, and then placing the apparatus in a broad dish, and surrounding it with water.

EXPERIMENT II,

Rapid combustion of sulphur.

Take a large receiver, or any other round-bellied bottle with a wide orifice, containing a little water; fit a bung