CH EMISTRY. 
25© 
lees of wine. Thefe experiments prove, that the gallic 
acid has a greater affinity with zircon than the muriatic 
acid poffeffes, and that the gallats of zircon and iron are 
foluble in muriatic acid, finceapartof them remains in 
folution in the liquor which was feparated by carbonat of 
ammoniac. 
Carbonat of potaffi, faturated with carbonic acid, pre¬ 
cipitates zircon from its folution in muriatic acid j and, 
though this folution be made with effervefcence, the pre¬ 
cipitate, when waffied and dried in the air, retains a 
large portion of carbonic acid ; for this earth afterwards 
produces a lively efterve’i'cence, when dill'olved in acids. 
A folution of fulphurated hydrogen gas in water, mixed 
with, a folution of muriat of zircon containing iron, dif- 
turbs the tranfparency of the folution, and gives to it a 
reddiffi colour; but it does not occafion a true precipi¬ 
tate. The hydro-l'ulphure of ammoniac inftantly preci¬ 
pitates this lalt of a beautiful green colour, which be¬ 
come black when dry. This precipitate, when placed 
on burning coals, gives out the fmell of fulphurated hy¬ 
drogen gas, and becomes of a blueifh (lightly purplilh 
colour by pulverization ; before it has been heated it af¬ 
fords a powder of a pearl grey colour. This colour is 
owing to the oxyd of iron combined with the zircon. 
The carbonat of ammoniac produces at firfb a depofi- 
tion in muriat of zircon, but freffi quantities of the am- 
moniacal fait re-diifolve the greater part of the precipi¬ 
tate. In this cafe, a triple lalt is formed, which may be 
decompofed by heat. The prufliat of mercury produces 
in the folution of muriat of zircon, a very copious pre¬ 
cipitate, foluble in muriatic acid. This depolition can¬ 
not be owing to the combination of the mercury with 
the muriatic acid, for none of the falts into which it en¬ 
ters forms a precipitate with the prufliat of mercury. 
Were we even to fuppofe this cafe to be an exception, 
ftill the depolition would not be l'oluble in Ample muri¬ 
atic acid. 
A plate of zink, introduced into a folution of muriat 
of zircon, occafions a flight effervefcence, owing to the 
difengagement of hydrogen gas. The liquor becomes 
milky, and at the end of feme days aflumes the form of 
a white femi-tranfparent jelly. Pure alumine decom- 
pofes the muriat of zircon, by the affiftance of a flight 
heat. The alumine is difl'olved, the liquor becomes 
milky, and aflumes a gelatinous form by cooiing. When 
the muriat of zircon contains iron, it remains in folution 
along with the alumine, l'o that the zircon which is pre¬ 
cipitated does not contain any fenfible quantity of that 
metal; it therefore furnilhes an eafy and Ample method 
of feparating thisearth from the iron with which it is mixed 
in hyacinths, and which adheres to it very ftrongly. 
Muriat of Silex—T his fait is very little known ; 
Fourcroy was the fir It who obl'erved it. To prepare it, 
the lilex is to be melted with the alkali, and muriatic 
acid poured on the mixture; the fiiex difl'olves in the 
acid, and always retains an excels of acidity; the fiiex 
may be precipitated by heat, and muriat of potalh and 
of fiiex is produced. This fait reddens the blue vegeta¬ 
ble colours ; and is decompofed by heat. Its other pro¬ 
perties have not yet been al'certained. 
Super-oxygenated Muriat of Potash. —This 
fait, lately difcovered by M. Berthollet, is prepared by 
palling oxygenated muriatic acid gas into a lolution of 
can flic potalh, or combined with carbonic acid. The 
apparatus may be the fame as that already depifted and 
defended for oxygenated muriatic acid, except that in 
the Woulf 's bottled, inftead of water, a folution of pot¬ 
alh mult be put. The belt proportion between the water 
and the potalb, is fix parts of the former, and one of the 
latter. When carbonat of potafli is employed, there 
arifes in a certain time an effervefcence from the difen¬ 
gagement of the carbonic acid; with caullic potafli there 
is no effervefcence, but a little heat is produced : the dif¬ 
ference is ealily underftood. As the luper-oxygenated 
muriat of potafli is not by far lb foluble as potaffi, as 
z 
foon as a certain quantity is produced, it cryftallize? in 
the middle of the liquor in the form of ffiining fpangles, 
the quantity increafmg as the laturation goes on. Ber¬ 
thollet, when he examined the refult of the experiment, 
found that the oxygenated muriatic acid did not com¬ 
bine with the potafli as it came over; on the contrary, 
it divided into two parts, one of which gave out its 
oxygen to the other, l’o that there were formed fuper- 
oxygenated muriatic acid and common muriatic acid, 
which both uniting with the potalh, give birth to com¬ 
mon muriat of potaffi, and luper-oxygenated muriat of 
potalh. There are therefore three affinities in this ope¬ 
ration: that of a frefli quantity of oxygen for the oxyge¬ 
nated muriatic acid ; of this for the potafli; and of the 
common muriatic acid for the fame alkali. 
The folubility of thefe falts being very different in 
cold water, their feparation becomes eafy ; it is fufficient 
to collect the fait which has cryftallized during the ope¬ 
ration, todifl’olve it in the requifite quantity of boiling 
water, to filter the folution to feparate it from a fmall 
quantity of earth which is found in common potafli, and 
then to let it cool. The fuper-oxygenated muriat is 
depofited in brilliant laminae. To obtain it dry, decant 
the luper-natant liquor; let it drain, and then dry it up¬ 
on blotting-paper. As the luper-oxygenated muriat of 
potafli is not very foluble in cold water, but little re¬ 
mains foluble in the refiduary or mother-waters; yet it 
may be colledfted without lofs, if the liquor be reduced 
by boiling, and then left to cool. 
This fait generally takes the form of very thin fquare 
plates ; fometimes it is in a parallopiped fliape. In tafte 
it is cool and pungent, like faltpetre : if fuies on light¬ 
ed coals, in the manner of faltpetre, but with more velo¬ 
city, and a brighter flame. Ground on porphyry, or in 
a marble mortar with a wooden peftle, it crackles, and 
emits fparks. It is eafily decompofed by diftiilation in a 
retort ; and, with a gentle heat, gives very pure oxy¬ 
gen gas : 100 parts of the fait furniffi about 0-33 of its 
weight of oxygen gas. If prepared with care, and the 
diftiilation be made (kilfully, the oxygen gas which is 
formed is almolt all ablorbed by the pholphorus; Ber¬ 
thollet had but from o - oz to z'oj of reiidue, and even 
that proceeded from air in the apparatus, which it is dif¬ 
ficult to avoid. The flight heat at which the oxygen 
quits the muriat of potalh, (hews that this principle does 
not adhere to it very ftrongly, or that it retains in its 
combination a great quantity of caloric; as appears from 
.feveral circumltances wherein the fuper-oxygenated mu¬ 
riat is decompofed by combultible bodies. 
Barytes does not decompofe this fait. If thrown into 
concentrated fulphuric acid, it detonates, flies to a dis¬ 
tance from the velfel, and gives out a deep-red light. 
With concentrated nitric acid, it crackles and emits 
fparks, but not with explolion, as in the preceding cafe. 
Mixed with lulphur, in the proportion of three parts of 
the muriat to one of fulphur, and triturated in a metal 
mortar, it produces a fuccelfion of ftrong detonations, 
like the report of piftols, if the experiment be made with 
only about fifteen grains. The lame mixture detonates 
more ftrongly under the hammer: it flames in concen¬ 
trated fulphuric acid, and burns with a very bright light. 
A mixture of three parts of this fait, one part and a half 
of fuiphur, and one half part of charcoal, produce the 
like effe£T, but in a much more violent degree. Several 
of the very combultible metals, as iron, antimony, zink, 
arfenic, and the metallic fulphures, mixed with t.vo 
parts of oxygenated muriat, detonate with flame by a 
blow, but do not flame in fuiphuric acid. Several vege¬ 
table matters, as oils, iugar, Itarc-h, alcohol, ether, faw- 
dult, &c. produce tiie lame effects. All thefe mixtures 
detonate with the elehtric fliock, producing a very vivid 
flame. 
Thefe experiments, for which we are indebted to 
Fourcroy and Vauquelin, prove, that the oxygen is 
much lei’s attached to the muriat of potalh than to the 
nitratj 
