C H E M : 
iymmetrical arrangement, difpofetl in needles; which 
forms a cryftallization of lulphur. If fulphur be melted 
in oil, it is fuper-faturated, and holds in folution more 
than it can diffolve; when cold, it gives over the excels 
in the form of eight-fided cryftals. 
Slow combujiion of fulphur. —Take a large bell-glafs, and 
put beneath it a little cup withflowers of lulphur lighted ; 
let this in a dilh, and ltirround it with water. A white 
fmoke will arife, which diffolves in the water, and be¬ 
comes acid ; this is fulphureous acid. 
Rapid combujiion. Take a great balloon with a large 
aperture; fufpend in the infide an iron fpoon, contain¬ 
ing a mixture of fulphur and nitrat of potalh compofed 
of feventy-two parts of fulphur to feven of the nitrat. 
Set fire to the mixture, and Hop the aperture of the bal¬ 
loon. Or, put lighted fulphur into oxygen gas; it 
burns with extreme rapidity. In both cafes, a little wa¬ 
ter mult be put in the bottom of the balloon, to abforb 
the acid which is produced : this is fulphuric acid. It ap¬ 
pears, therefore, that, according to the manner in which 
the fulphur is burned, it abforbs more or lefs oxygen, 
and becomes more or lefs acid. With fulphur and azot 
there is no adtion or effedt. 
Sulphurated hydrogen gas. —This may be obtain¬ 
ed in various ways, which we lhall explain as we come to treat 
of thofe bodies from which it may be drawer. The only 
method we can defcribe in this place is, to pafs hydro¬ 
gen gas through fulphur in fufion ; at the moment that 
the hydrogen gas is difengaged, throw in fublimed ful¬ 
phur, and under the gas will be found fulphurated hy¬ 
drogen gas. The bell method is to put into a gun-bar¬ 
rel fome fulphur in powder; pafs the barrel through a 
furnace; fix at the lower extremity a bent tube which is 
to go under a jar in the mercurial apparatus ; fix on at 
the upper extremity the apparatus for producing hydro¬ 
gen gas itlelf, as reprefented in the Chemiftry, Plate II. 
fig. 12. Melt the fulphur with a gentle heat; when it is 
melted, let the hydrogen gas run through it; and under 
the jar will be found fulphurated hydrogen gas. 
Properties of this gas. —It is an elaftic fluid, very light, 
quickly volatilifing in the atmofphere j it kills animals 
•very quickly; turns fyrup of violets to a green colour; 
extinguifhes a taper; mixed with atmol'pherical air or 
oxygen gas, it flames, and detonates by the eledlrical 
fpark ; it burns with a reddifh blue flame, and lets fall 
fome fulphur. Atmofpherical air deltroys this gas, as 
may be perceived by placing them in contadl under a 
jar. Oxygen then has more attraction for hydrogen than 
fulphur has for oxygen; the oxygen and hydrogen com¬ 
bine and form water. It is remarkable that this experi¬ 
ment cannot behnade at a high temperature, becaufe the 
fulphur would burn, and that a low temperature is infuf- 
flcient to make it burn ; this fulphur fpreads itfelfon the 
f urrounding bodies. Hence arifes the fulphur which we 
fee about mineral fprings; and why the gas difengaged 
from thofe fources turns filver of a black colour. Ni¬ 
trous acid and fulphureous acid decompofe it. It is ab- 
forbed by water. Sulphurated hydrogen diffolved in 
water, reddens the tinfture of turnfole, the paper ftained 
therewith, and the tindture of radifli; it combines with 
alkalis, barytes, lime, and magnefia; and with thefe 
fubftances it forms combinations, which, mixed with 
metallic folutions, change the bafes. It decompofes 
foap, and takes the place of oil, in alkalis; it precipi¬ 
tates, in a great meafure, the fulphur in the folutions 
of fulphure of potafh or of lime, and tends to form a 
triple combination with the remainder. It precipitates 
metallic diffolution : yet fulphur and carbon have no ac¬ 
tion. 
Combination of pbofphorus with fulphur. —Put a mat- 
trafs one part of phofphorus with an eighth of its weight 
of fulphur, and thirty-two parts of diftilied water; in a 
gentle heat the pholphorus liquefies, and dilfolves the 
lulphur. The new combination affumes a yellow colour 
S T R Y. 203 
and remains fluid under the water till the 20th degree 
above o in Reaumur’s thermometer ; after that it con¬ 
geals. One part of phofphorus, with half its weight of 
fulphur, give a product which remains fluid under water 
at 8° above o. One part of phofphorus and two of ful¬ 
phur combine very well in a gentle heat, and always un¬ 
der water; this combination is fluid at io° above o; 
but it forms a cryftallization, fo that one portion ap¬ 
pears fluid, the other,concrete. One part of phofphonas 
may aifo unite with three of fulphur : put into a matrafs 
one part of phofphorus with fome diftilled water; heat 
the matrafs till the phofphorus melts ; then add the ful¬ 
phur, which muft be divided into three parts: the firft part 
is prefently diffolved by the phofphorus, fome bubbles 
of air are difengaged alfo in the moment of combination ; 
then add the fecond part of the fulphur, and afterwards 
the third, which are diffolved in like manner; and the 
new produft remains fluid under the water as long as it 
maintains 30® of heat; but, as the water gets cold, the 
combination becomes concrete and friable. 
Some of the more remarkable properties of alkaline 
fulphures, have been recently inveltigated by the fociety 
of Dutch chemilts. By expofmg two equal quantites of 
frefh fulphur of potafh to equal volumes of atmofpherical 
air, the one confined by mercury, the other by water, 
thefe chemifts obferved, that at the end of a few days 
the volume of the air over the mercury was not dimi- 
nifhed, while that of the air over the water in the fame 
fpace of time was diminifhed nearly one fourth. This 
air, on examination, was found to be completely depriv¬ 
ed of its oxygen gas. Effedts quite fimilar were produc¬ 
ed by ufing fulphure of barytes. The abforption of oxy¬ 
gen gas took place alfo in the air over mercury when the 
fulphure had been previoufly moiftened with a little wa¬ 
ter. A confiderable difengagement of caloric was pro¬ 
duced at the moment the water came into contadt with 
the fulphure. 
In expofmg nitrous gas to alkaline fulphures this gas 
was deprived of its oxygen in the fame manner as atmof¬ 
pherical air. The dry fulphures, however, had no adlion 
on this gas, but as foon as a little water was added, an 
abforption of oxygen gas immediately began to take place. 
Thefe fadls were fufficient to fhow that the attradlion of 
the fulphure for oxygen, in thefe experiments, was not 
exerted diredtly, but only through the intervention of 
water. With a view to difcover the fliare which water 
has in producing this abforption of oxygen gas, a quan¬ 
tity of aqueous vapour was made to pafs through hot 
alkaline fulphure, and it was found that fulphurated hy¬ 
drogen gas alone puffed over into the receiver. When 
muriatof barytes was added to a lolution of the fulphure 
ufed in this experiment, a copious precipitation of fulphat 
of barytes took place. This experiment (flowed that it 
was the water which had been decompofed, and that it 
‘was the oxygen of this fluid which had united with the 
fulphur of the fulphure to form fulphuric acid. Sulphure 
of lime, through which aqueous vapour had been pafled, 
afforded the fame refults. Thefe chemifts, however, were 
not able to effebt the direbt combination of fulphur with 
hydrogen, by paffmgthis gas through alkaline fulphures 
in a high temperature. Sulphurated hydrogen gas was 
quickly abforbed by the cauftic folutions of ammoniac, 
foda, and potafh. Lime water produced the fame effedt, 
but with lefs rapidity. The fulphurated hydrogen gas 
could be feparated from the alkali by the addition of'an 
acid in a quantity equal to that which had been ablorb- 
ed. Alkalis, in their dry ftate, did not abforb this gas; 
but the addition of a little moifture occafioned an im¬ 
mediate abforption. When fulphurated hydrogen gas 
was brought into contact with ammoniacal gas, a com¬ 
bination took place, and the gafes were deprived of their 
elafticity. The fulphurated hydrogen gas could be dif¬ 
engaged by adding an acid, which united with the am¬ 
moniac. By expofmg the fulphurated hydrogenated 
ammoniac 
