234 C H E M I 
zircone purs. In a high temperature, charcoal converts 
this fulphat into a fulphure. This fulphure is eafily fo- 
luble in water; and its folution furnilhes, by evaporation, 
cryftals of hydro-fulphure of zircone. This fait under¬ 
goes no material change with other acids. Earths and 
alkalis decompofe it. 
Of SULPHITS. 
This is the name given to combinations of fulphurous 
acids with earths and alkalis. We are indebted for the 
knowledge of thefe falts to Vauquelin and Fourcroy. 
See Annales de Chimie, tom. xxiv. 
The artifice of making fulphits in general, is by mix¬ 
ing alkaline or earthy folutions with water loaded with 
fulphurous acid. Or by palling fulphurous acid on the 
bales. Or, which is the belt method, by putting char¬ 
coal in powder, and fulphuric acid, into a retort; gafe'ous 
fulphurous acid is formed, and carbonic acid. This is 
effefted by the following apparatus : In the Chemiftry 
Plate V. fig. i, A, is glafs retort, luted, laid acrofs iron 
bars in a furnace ; to its mouth is adapted a bent tube, 
which is plunged into a two-necked bottle B, containing 
water to abforb the fulphuric acid which might pafs over 
without being decompofed ; from the other neck of this 
bottle proceeds a tube, which terminates in the three¬ 
necked bottle C, containing a folution of carbonat of 
potalh ; in this manner there may be placed as many bot¬ 
tles as there are fulphits to prepare ; the laffc is termi¬ 
nated by a bulbed tube of fafety, whole extremity runs 
under the inverted jar D, in the pneumatic apparatus. 
In the middle opening of each jar, there mult be the 
tubes of fafety EEE, one of whofe extremities Ihould 
be plunged a little way into the water, with the upper 
end open to the atmofphere, in order that, if the heat 
Ihould fall off during the operation, or after it is finilh- 
t:d, it may give a paffage to the outward air, in propor¬ 
tion as the gas diminilhes in volume by cooling,and there¬ 
by hinder the folution of the fulphit from getting into 
the firll bottle, and mixing with the water it contains, 
by the prelfure of the atmofphere. To try whether an 
apparatus fo complicated be perfect in all its parts, blow 
with the mouth into the firit tube of fafety E; the air 
Ihould regularly proceed into the jar D, palling through 
the oppolition it meets from the fluid columns that dil- 
pute its palfage, which oppofition will caule it to efcape, 
if all the joinings are not very clofe and tight. It is the 
tubulated bottles, that are very fubjeft to have cracks in 
the joinings of the necks. When all is in perfeft order, 
heat the retort gently: the fulphurous acid is foon dilen- 
faged in the galeous Hate, and faturates the potalh, foda, 
&c. and under the jar D, carbonic acid is collected ; ari- 
fmg, i, from the decompofition which takes place in the 
retort; a, from the carbonic acid which is difengaged 
in the decompofition of the liquid carbonats contained in 
the bottles, which carbonats are decompofed, in propor¬ 
tion as the fulphurous acid drives off the carbonic acid 
to feize upon the bale, and form fulphits. 
The above is the molt advantageous method of pre¬ 
paring fulphits ; as they may thus be obtained cryllal- 
lized without evaporation. When they are made with 
liquid fulphurous acid, evaporation is necelfary ; which, 
by giving accefs to the oxygen, fulphuric acid and ful- 
phats may be produced. 
Sulphits have no fmell. When they are not neuter, 
they entirely dilcolour the blue vegetable tints ; hence 
it is that the vapour of fulphur, or fulphurous acid, is 
ufed for bleaching filk, linen, &c. They have a Itrong 
tafte of fulphurous acid ; they are decompofed by caloric 
or heat. Oxygen gas changes them into lulphats. Sul¬ 
phits may ferve for eudiometers, efpecially that of ammo¬ 
niac, which of all fulphits palfes the moft eafily into the 
irate of a fulphat, by mere contaft with the oxygen of 
the atmofphere. Some are foluble in water; other’s not, 
except with an excefs of acid. They are decompofed 
by acids. They are all, except that of ammoniac, con- 
2 
S T R Y. 
verted into fulpbures by charcoal. Alkalis and earths 
aft upon thefe fairs in proportion to their affinities for the 
fulphurous acid : thus barytes decompofes all the other 
fulphits ; then the order of affinity or attraftion is, ftron • 
tian, lime, potalh, foda, magnefia, ammoniac, glucine, 
alumine, and zircone. 
Sulphit of Barytes. —To prepare this fait, mix a 
folution of iulphit of foda or ammoniac, with a folution 
of muriat of barytes : the fulphit of barytes then appears 
in the form of very little needles precipitated at the bot¬ 
tom of the liquor. 
This fait has no fenfible tafte ; it is white and opaque. 
Caloric decompofes it, by driving off the excefs of ful¬ 
phur, and it becomes a fulphat; the fulphur cryltallizes 
in the neck of the matrafs. Charcoal decompofes it, and 
changes it into a fulphat, by feparating the oxygen. It 
is not foluble in water, at lealt not fenfibly; fulphurous 
acid renders it fomewhat foluble. The fulphuric, mu¬ 
riatic, and nitric, acids, decompofe it, with violent crack¬ 
ling and great boiling up. Oxygenated muriatic acid 
converts it entirely into a fulphat. No terreftrial or al¬ 
kaline lubftance decompofes fulphit of barytes. It con- 
fifts of barytes fifty-nine, fulphureous acid thirty-nine, 
and water two. 
Suxphit of Strontian.— This is not yet fuffici- 
ently known for us to detail its properties; they are do’ubt- 
lefs much the fame as the fulphit of barytes. 
Sulphit of Lime. —The belt way to make fulphit 
of lime, is to pafs fulphurous acid gas through the midft 
of carbonat of lime diluted with water. When the liquor 
is well faturated, it cryltallizes on the fides of the jar in 
tranfparent needles. It has at firll little or no tafte, but 
afterwards refembles fulphurous acid. Caloric makes 
this frit pafs into the ftate of a fulphat. It loles fomewhat 
of its tranlparency in cryftallizing; but goes very llowly 
into the fulphat ftate. The form of fulphit of lime is 
that of a prifm with fix planes, terminated by a very 
long pyramid. 
This fait requires 800 parts of water to difl'olve it, but 
an excefs of acid renders it more eafy of folution; and 
thus may it be obtained in cryftals by expofing its folu¬ 
tion in fulphurous acid to the air. 
Barytes is the only earth which decompofes fulphit of 
lime: the acid is diftipated, leaving the fait in a ftate 
of purity. This may be tried, by mixing a folution of 
this earth with a folution of neutral fulphit of lime, 
which forms a flight precipitate. The mineral acids de¬ 
compofe it; fulphuric acid difengages the fulphurous 
acid with effervefcence: indeed it may be extrafted thus 
in a ftate of the greateft purity. The nitric acid and 
oxygenated muriatic acid convert it partly into fulphat 
of lime. It confifts of lime forty-feven, fulphureous acid 
forty-eight, and water five. 
Sulphit of Potash. —To prepare this fait, take 
very pure carbonat of potafh crvftallized ; difl'olve it in 
three times its weight of diftilled water; then pafs ful¬ 
phurous acid gas into the mixture until the effervefcence 
ceafes entirely. During this combination, a fmall quan¬ 
tity of caloric is difengaged, and the folution cryltallizes 
by cooling. This l'alt is ufually white and tranfparent j 
fometimes it is flightly yellow and femi-tranfparent, if 
its folution has been very concentrated, and the cryftal- 
lization confufed. Its tafte is penetrating and fulphure¬ 
ous ; its figure that of a rhomboidal plate; its cryftalli- 
zation often prefents fmall needles diverging from a com¬ 
mon centre. When expoled to a fudden heat, it decre¬ 
pitates, and lofes its water of cryftallizafion ; afterwards, 
by ignition, it emits fome vapours of fulphureous acid. 
At length a portion of fulphur is feparated, and the re- 
lidue is fulphat of potalh, with a flight excefs of alkali. 
By expoliire to air, it flightly effiorefees, becomes 
opake ana hard, its penetrating fulphureous tafte difap- 
pears, and it acquires another which is acrid and bitter. 
In this ftate it no longer eftervefees with acids. 
Take twelve parts of this fait dried, which put into a 
retort 
