SUL 
SUL 
SUL 
730 
2. If a considerable piece of sulphur is ex- 
E osed to a sudden though gentle heat, by 
olding it in the hand, for instance, it breaks 
to pieces with a crackling noise. 
When sulphur is heated to the tempera- 
ture of about 170°, it rises up in the form of 
a line powder, which may easily be collected 
in a proper vessel. This powder is called 
flowers of sulphur. When substances fly off 
in this manner on the application of a mode- 
rate heat, they are called volatile ; and the 
process itself, by which they are raised, is 
called volatilization. 
When heated to the temperature of 212° of 
Fahrenheit’s thermometer, it melts and be- 
comes as liquid as water. If this experi- 
ment is made in a thin glass vessel, of an egg 
shape, and having a narrow mouth, the ves- 
sel may be placed upon burning coalswithout 
much risk of breaking it. The strong heat 
soon causes the sulphur to boil, and converts 
it into a brown-coloured vapour, which tills 
the vessel, and issues with considerable force 
out from its mouth. 
3. Sulphur is capable of crystallizing, if it 
is melted, and as soon as its surface begins to 
congeal, and the liquid sulphur beneath is 
poured out, the internal cavity will exhibit long 
needle-shaped crystals of an octahedral figure. 
This method of crystallizing sulphur was con- 
trived by Rouelle. If the experiment is 
made in a glass vessel, or upon a flat plate of 
iron, the crystals will be perceived beginning 
to shoot when the temperature sinks to 220°. 
4. If sulphur is kept melted in an open ves- 
sel, it becomes gradually thick and viscid. 
When in this state, if it is poured into a bason 
of water, it will be found to be of a red colour, 
and as soft as wax. In this state it is em- 
ployed to take off impressions from seals and 
medals. These casts are known in this coun- 
try by the name of sulphurs. When exposed 
to the air for a few days, the sulphur soon re- 
covers its original brittleness, but it retains 
its red colour. It is supposed at present, that 
sulphur, rendered viscid and red by long fu- 
sion, has combined with a little oxygen. It 
-is therefore no longer pure sulphur, but a 
compound of sulphur and oxygen. Mr. 
Fourcroy has given it, when in this state, the 
name of oxide of sulphur. 
5. When sulphur is heated to the tempera- 
ture of 560° in the open air, it takes fire spon- 
taneously, and burns with a pale blue flame, 
and at the same time emits a great quantity of 
fumes of a very strong suffocating odour. 
When set on five and then plunged into a jar 
fall of oxygen gas, it barns with a bright red- 
dish white flame, and at the same time emits 
a vast quantity of fumes. If the heat is con- 
tinued long enough, the sulphur burns all 
away without leaving any ashes or residuum. 
If the fumes are collected, they are found to 
consist entirely of sulphuric acid. By com- 
bustion, then, sulphur is converted into an 
acid. 
The combustion of sulphur, in fact, is no- 
thing else than the act of its combination with 
oxygen ; and for any tiling which we know to 
the contrary, it is a simple substance. 
6. The affinities of sulphur, according to 
Bergman, are as follows: 
Fixed Alkalies. 
Iron, Antimony, 
Copper, .Mercury, 
Tin, Arsenic, 
Lead, Molybdenum, 
Silver, Bismuth. 
SULPI1URETS are combinations of alka- 
lies or metals with sulphur. 
SULPHURIC ACID is generally pro- 
cured by burning a mixture of sulphur and 
nitre in chambers lined with lead. The 
theory of this process requires no explana- 
tion. The nitre supplies a quantity of oxy- 
gen to the sulphur, and the air of the atmo- 
sphere furnishes the rest. The acidjthus ob- 
tained is not’ quite pure, containing a little 
potass, some lead, and perhaps also nitric and 
sulphurous acids. At first it is very weak, 
being diluted with the water necessary for 
condensing it ; but it is made stronger by 
distilling off a portion of this water. By this 
process it is made quite transparent ; but it 
still contains a little lead, which it dissolved 
from the vessels in which it was manufactur- 
ed, and a little potass which it acquired from 
the nitre employed in burning the sulphur. 
To obtain it in a state of complete purity, the 
sulphuric acid of commerce must be distilled. 
This is easily done by putting it into a small 
retort with a long beak. The bottom of the 
retort is placed upon a fire of charcoal, and 
fixed steady by means of an iron ring ; while 
its beak is plunged half-way into a receiver, 
whose mouth it fits nearly, but not exactly. 
The acid soon boils, and is gradually con- 
densed in the receiver. Too great a quan- 
tity should not be distilled at once, otherwise 
the retort generally breaks in consequence of 
the violent agitation into which the boiling 
acid is thrown. 
Sulphuric acid is a liquid somewhat of an 
oily consistence, transparent and colourless as 
water, without any smell, and of a very strong 
acid taste. When applied to animal or vege- 
table substances, it very soon destroys their 
texture. 
It always contains a quantity of water ; part 
of which, however, may be driven off by the 
application of a moderate heat. This is call- 
ed concentrating the acid. When as much 
concentrated as possible, its specific gravity 
is said to be 2.000 ; but it can seldom be ob- 
tained denser than 1.85. 
It changes all vegetable blues to a red ex- 
cept indigo. According to Erxleben, it boils 
at 546° ; according to Bergman, at 540°. 
When exposed to a sufficient degree of 
cold, it crystallizes or freezes ; and after this 
has once taken place, it freezes again by the 
application of a much inferior cold. Sul- 
phuric acid has a very strong attraction for 
water. 
Mr. Lavoisier attempted to ascertain the 
proportion of the constituents of this acid, by 
measuring the quantity of oxygen absorbed 
by a given weight of sulphur during its com- 
bustion. His result was 71 parts of sulphur, 
and 29 of oxygen. But this method was not 
susceptible of sufficient precision to warrant 
much confidence. Mr. Thenard had recourse 
to a much better method, which was em- 
ployed still more lately for the same purpose 
by Mr. Chenevix with much address. Nitric 
acid was distilled off 100 parts of pure sulphur 
repeatedly, till the whole sulphur was con- 
verted into an acid. The sulphuric acid, thus 
formed, was separated by means of barytes, 
with which it forms an insoluble compound. 
The 100 parts of sulphur, thus acidified, | 
yielded 694 parts of d«rv sulphat of barytes. | 
Hence 100 parts of sulphat of barytes con- ! 
tain 14.5 parts of sulphur. By another set of f 
experiments, to be described hereafter, Mr. i 
Chenevix ascertained, that 100 parts of sul- j 
phat of barytes contain 23.5 parts of sulpha- - 
l ie acid. Hence it follows that 23.5 parts of ! 
sulphuric acid contain 1 4. 5 of sulphat ; the 
remaining 9 parts must be oxygen. There- 
fore sulphuric acid is composed of 14.5 parts 
of sulphur and 9 of oxygen ; or, which is the 
same thing, of 61.5 sulphur 
38.5 oxygen 
100.0 
Sulphuric acid is not altered by the action 
of light nor caloric. It does not combine with 
oxygen. It was affirmed, indeed, by some 
chemists, that sulphuric acid might be com- 
bined with oxygen by distilling it oft - the 
black oxide of manganese ; but the assertion 
wasrefuted by the experiments of Vauquelin. 
None of the simple combustibles act upon 
it at the usual temperature of the atmos- 
phere, or at least, their action is so slow as not 
to be perceptible. But when they are assist- 
ed by heat, they are ail capable of decom- 
posing it. 
When sulphur is boiled in this acid, it ab- 
sorbs a portion of its oxygen, or at least com- 
bines with it, and the wliole is converted into 
sulphurous acid. Phosphorus also absorbs 
oxygen from it by the assistance of heat, sul- 
phurous acid is driven off, and phosphoric 
acid formed. At the boiling temperature 
charcoal also absorbs oxygen from it, and 
converts it into sulphurous acid. At a red 
heat it even converts it into sulphur. When 
hydrogen gas and sulphuric acid are made to 
pass together through a red-hot tube of porce- 
lain, the acid is completely decomposed, wa- 
ter is formed, and sulphur deposited. 
Azole has no action on sulphuric acid ; but 
this acid readily absorbs muriatic acid, and 
forms with it a liquid of a brownish tinge, 
which emits the dense and suffocating odour 
of muriatic acid, and corrodes vegetable and 
even metallic bodies near which it happens to 
be placed. 
When zinc or iron is thrown into sulphuric 
acid, a violent action takes place, if the acid 
is diluted ; water is decomposed, its hydro- 
gen flies off, and its oxygen combines with 
the metals. If the acid is concentrated, the 
action is much less violent, and sulphurous 
acid exhales. Upon tin and copper the acid 
acts very slowly and feebly, unless its action 
is assisted by heat, when it oxidizes and dis- 
solves them. On silver, mercury, antimony, 
bismuth, arsenic, and tellurium, it does not 
act except at pretty high temperatures. These 
metals abstract part of its oxygen, and con- 
vert one portion of it into sulphurous acid, 
while another portion combines with the 
oxides thus formed. When boiling-hot it ox-' 
idizes lead, and dissolves cobalt, nickel, and 
molybdenum : but it has no perceptible action 
on gold or platinum at any temperature to 
which it can be raised. 
It unites readily with all the alkalies and 
earths except silica, and with most of the me- 
tallic oxides, and forms salts denominated sul- 
phats. Thus the combination of sulphuric i 
acid and soda is called sulphat of soda ; the* 1 
