SUL ( 554 ) SUL

due, chiefly orpimcnt; the belt Sicilian fulphurin fmall rolls, contains hardly more than 3 percent, of refidue which appears to be little elfethan, earth, , as it affords no arfenical odour whenheated with charcoal..

To the tafte lulphur is perfectly infipid,when broken down however by the teeth, itmanifefts a peculiar indefcribable grittinefs,which fufficiently diftinguifhes it from all otherbodies.. It is inodorous at the common tempe-rature, but when rubbed a flight fetid fmell is-fulhciently perceivable; if a roll of fulphur .isheld for a minute in a moift warm hand, itbreaks acrofs with a fharp crackling not unlikethe fnapping from the difcharge of an electricalfpark, the hand at the fame time contracts apeculiar difagreeable odour, which Iafts fomeminutes. When expofed to a temperature ofabout 224 0 Fahr. 'it melts into a tranfparentbrownifh red fluid; by an increafe of heat, thefluidity diminifltes and the fulphur begins tofublime in vifible vapours; when it fomewliatexceeds the temperature of 300° Fahr. its con-fidence will.be vifcid and thick like treacle, andthe vapour will take fire, the inflammation in-ftantly fpreading to the reft of the rnafs.

If a crucible or ladle full of fulphur be al-lowed to cool gradually, and the fluid centralpart be let out juft before it folidifies, by pierc-ing the outer cruft, tire cavity will be found tobe entirely lined with comprefled needle-fhapedcrvftals. When fulphur has become vifcid byheat its fluidity may be reftored merely by low-ering its temperature ; if it is kept in thisthick ftate for a few minutes, and then withoutprevious cooling is poured into warm water, itwill be of a brown colour, foft and confiderablyplaftic; in this ftate it is a very ufeful materialto artifts and modellers for taking impreflionsof feals, gems, &.c. efpecially as in the courfeof a few hours it refumes the hardnefs andother properties of common fulphur. This foftfulphur is confidered by Fourcroy (but wethink without fufheient proof) to be an oxyd offulphur.

VVater in the ftate of fleam is partly decom-pofable by melted fulphur, an inflammable gas,perhaps lulphuretted hydrogen, being produced.With oxygen, fulphur combines in two-propor-tions; if this latter is heated in common air till-it becomes thick, it takes fire, burns with a blueflame, and is converted into a pungent highlyfuffocating acid gas called Sulphureous Acid;if on the other hand it is fet fire to in oxygengas, the flame which it emits is of a reddiih

purple colour, and the acid produced is Snf>phuric mixed with fulphureous.

The chief acids that have any a£tion on ful-phur are the nitric, oxymuriatic, and fulphuric.The former is decompofed upon fulphur at aboiling heat, nitrous gas is given out, and ful-phuric acid is the refult. The fecond in like-manner acidifies the fulphur, but with fomepeculiar phenomena deferibed under the articleSulphurized Muriatic Acid. Sulphuric acidwith fome difficulty takes up a fmall proportionof fulphur, and fulphureous acid is produced,partly from the oxygenation of the fulphur, amipartly from the deoxygenation of the fulphuricacid.

The alkalies and alkaline earths combinewith fulphur forming the' important ckifs of-Alkaline Sulphurets. Molt of the metals andmetallic oxyds alfo combine with fulphur andproduce the clafs of Metallic Sulphurets.Sulphur unites with hydrogen, forming Hepaticgas or Sulphuretted Hydrogen. The com- -binations of fulphur with carbon and with phos-phorus, have been already deferibed under thofcarticles.

Sulphur when in fine powder is fparinglyfoluble by digeftion in highly rectified alcohol, .but a more concentrated folution is made by.prefenting each to the other in the ftate of gas;for this purpofe put fome fulphur into a cucur- •bit, and fufpend within- the fame-a vial filledwith alcohol, then lute on a head and properapparatus, and proceed to diftillation ; both thefulphur and alcohol are volatilized, and meeting 'with each other in the upper part of the vefielcombine readily together, and condenfe in thereceiver into a yellowifh ftrongly fmelling fluid,from which nearly the whole of the fulphur maybe again, precipitated by the addition of water.

Oil of turpentine and the other eflential oils ■diflolve a eonfiderable proportion of fulphur !when hot, the greateft part of which they again Idepofit in cryftals if cooled flowly. The fatoils unite with fulphur by boiling, and acquire a Jdeep yellowifh brown.colour, and a flrong fetid- .odour; the combination is generally called hal—Jam of Julphur. By long repofe in a cool place, .!it depofits fmall ottohedral cryftals of fulphur.

The order of affinities for this fubftance, ac-cording to Bergman is, fixed alkali, iron, cop-per, tin, lead, fdver, bifmuth, antimony, mer-cury, arfenic, and molybdena.

I he ufes of fulphur are very important. Itis employed in medicine; it enters into thecompofition of fulphuric acid, of gunpowder,,