SUL

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and of the common compofition for paying thebottoms of flaps. Its fumes when burning, areemployed for bleaching filk and wool, andchecking the progrefs of vinous fermentation.Common matches which are in daily ufe forlighting fires derive their principal utility frombeing tipped with fulphur.

SULPHUR, golden, of Antimony . See An-timony.

SULPHURET. I

SULPHURETTED HYDROGEN. V

HYDROSULPHURETS, &c. J

The various combinations 'of fulphur withalkaline, earthy, and metallic bafes, of fulphurwith hydrogen, and the latter compound withthe feveral bafes in different proportions offulphuration, are fo intimately connedfed witheach other in chemical enquiry, that we havepreferred to give the whole under one article,efpecially as the fubjedl is fomewhat in-tricate, and requires lorne attention to be fullyunderftood.

The feveral combinations which belong tothis fubjedl, are

1. Sulphuretted Hydrogen, compofed of hy-drogen holding fulphur in folution, and whenuncombmed with a bafe affuming the gaffeousform.

2. The Hydrofulphurets, or combinations offulphuretted hydrogen with the feveral alkaline,earthy, and metallic bafes, in which its adlionftrongly refembles that of an acid.

3. The Sulphurets, or combinations of ful-phur with the alkalies, earths, and metals.

4. Superfulphuretted Hydrogen, or fulphu-retted hydrogen, with a confiderable, but, ingeneral, an uniform excels of fulphur.

5. Sulphuretted Hydr0-fulphurets, or combi-nations of fulphur, fulphuretted hydrogen, andthe alkaline or earthy bafes.

Sulphuretted Hydrogen Gas, or HepaticAir. Gas Hidrogetie Sulfure of Berthollet ,and other French chemifts. Hydrothionic Acidof fome German authors.

The properties of this gas were firft explainedin a very excellent memoir by Mr. Kirwan,*and nearly at the fame time.by M. Gengembre, band the fociety of Dutch chemifts, and fincethis period they have been ftill more fullyunfolded by Berthollet , Fourcroy, Prouft, andother eminent chemifts. The moil ftriking andobvious properties of this gas are the following:it has a moll penetrating and -oftenfive fulphu-Teous fmell, fimilar to that of rotten eggs, or a-foul gun-barrel when wetted, but fomewhatlefs naufeous; it is rather heavier than common

* Phil. Trans, for 17 S 6 .

air; it is inflammable, and explodes like hydro-gen, only with lefs violence, when mixed withcommon air or oxygen; when moderately di-luted it may be breathed for a fliort time withoutdanger; it is abforbed readily by water to acertain extent, and then it reddens litmus, andhas a fweetifh but very naufeous tafte; it fpeed-ily blackens fome of the white metals, and alltheir folutions, particularly lead, filver, andmercury, and precipitates feveral metals fromtheir folutions; and laftly it combines copiouflywith the alkaline, earthy, and metallic bafes,faturating them like an acid.

This gas is procured in greatefl abundance bymeans of the folid fulphurets, either of thealkalies or of iron, and an acid. For this purpofeput fome pieces of the fulphuret of potafh (forexample) made by melting together equal partsof fulphur and common carbonat of potafh, intoa proof bottle, and add fulphuric or muriaticacid moderately dilute. An effervefcence willenfue, attended with an intenfely fetid fmell,and the fulphuretted hydrogen gas rifes inabundance. It may be colledled either overwater or mercury; if the former, part of it isabforbed by the water; if the latter, the mer-cury is a good deal blackened at the furface.This gas when obtained from the alkaline ful-phuret, unlefs a cauftic alkali be ufed, is how-ever mixed with carbonic acid, and thereforethis fulphuret is not fo good a material as thefub fulphuret of iron, or that in which the fulphuris in much fmaller proportion to the iron thanin the common native fulphuret or pyrites.The difference between thefe fulphurets hasalready been fully explained under the articleIron , (Vol. I. p. 623 iAfeq.) and a mafs veryconvenient for yielding the gas may be preparedby half-filling a crucible with common ironpyrites, covering it with a third or half itsweight of iron filings, over this prefling a littlecharcoal powder, and heating the whole mode-rately red-hot for a quarter of an hour. It isnot neceffary to urge the heat to the fufion ofthe materials. The pyrites andiron filings mavalfo be previoufiy mixed and treated as above.This gives a black brittle uniform mafs thatyields abundance of the gas with muriatic ordilute fulphuric acid. A mixture of three partsof iron-filings and one of fulphur fimply meltedtogether in a covered crucible, anfwers as wellas the pyrites and iron filings.

Sulphuretted hydrogen when pure is heavierthan common air (according to Kirwan) in theproportion of 10000 to 9038, fo that 100 cubicinches of it weigh about 33 grains. Wheij* Journ. de Fhyficpie for l“8j.

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