SUL 
getable, or animal matters. It is found in 
some mineral waters, but in greatest abun- 
dance in volcanic countries, wheire it is a 
valuable article of commerce. Sulpbur, as 
it is extracted from minerals and purified 
by art, is a bard, brittle substance, of a yel- 
low colour, which can be easily reduced to 
powder. It is always opaque, has a lamel- 
lated fracture, and becomes electric by fric- 
tion. The specific gravity, after it is melted, 
does not exceed 1.99. It has no smell, and 
very little perceptible taste. AVhen it is 
rubbed some time, it is volaf ized, and dif- 
fuses 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 trans- 
parent, 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 crystal- 
lizes 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 employed for taking im- 
pressions of seals and medals. In this state 
they are called sulphurs. When sulphur is 
exposed to heat in close vessels, it is vola- 
tized or sublimed in the form of a very fine 
powder, known under the name of flowers 
of sulphur. Sulphur enters into combina- 
tion with oxygen, azote, hydrogen, carbon, 
and phosphorous. 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 by 
melting the substance in a deep vessel, is of 
a dark violet colour, fibrous fracture, and 
tough consistence; the specific gravity is 
2.3. Anotlier oxide was formed by passing 
a current of oxymuriatic acid gas through 
flowers of sulphur. When sulphur is burnt 
in the open air, it emits a pale blue flame, 
SUL 
with a great quantity of white smoke. When 
these fumes are mixed with water, it is 
found to possess acid properties. This is a 
combination of sulphur with a greater pro- 
portion of oxygen than exists in the oxide, 
and is called sulphurous 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 ap- 
pears, that sulphur combines with oxygen in 
four different proportions. In two of these, 
in which the proportions are the small- 
est, the compounds are denominated ox- 
ides ; but in the two others, in w'hich the 
proportion of oxygen is increased, the com- 
pounds are acids, the properties of which 
will be afterwards noticed. 
SULPHURETS, in chemistry. Sulphur 
combines with the fixed alkalies forming 
compounds called sulphurets. These exist 
only in a concrete state, as when dissolved 
in water, a decomposition takes place. 
We may notice, as an example, the sul- 
phuret of potash, which is formed by ex- 
posing to heat in a covered crucible, equal 
weights of sulphur and the dry concrete 
alkali. When it has become concrete, it is 
firm and brittle, and of a reddish brown 
colour, which, from its resemblance to the 
liver of an animal, obtained the name of 
hepar sulphuris, liver of sulphur. This sub- 
stance, while dry, is inodorous, but when 
moistened it acquires a fetid smell from the 
production of sulphuretted hydrogen. It 
fuses when exposed to a strong heat. A 
singular property belonging to this sub- 
stance is, that when fused with some metals, 
as gold, a combination is formed, which is 
soluble in water. 
SULPHURETTED hydrogen, is a com- 
pound of sulphur and hydrogen, and it 
owes its origin to the decomposition of wa- 
ter in the processes by which it is formed. 
This substance is obtained by various me- 
thods, which are detailed by writers on 
chemistry. It may be had by exposing to 
a strong heat mixtures of sulphur with ve- 
getable matters, as sugar, oil, &c. The 
specific gravity is as 1.142 to 1 . Its smell 
is extremely foetid, approaching to that 
denominated putrid, the effluvia disengaged 
in the processes of putrefaction consisting 
partly of this gas. It extinguishes combus- 
tion, and is incapable of supporting animal 
