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than the preceding. The di&rence between the properties of
the salts of bar^tes and strontian furnishes an easy and exact
process, both for distin^ishing these two earths from one
another, and for separating them when in a state of mixture.
For this purpose, a solution of the earths in muriatic or acetic
acid is to be mixed with liquid silicated fluoric acid, and the
amount of the barytes is to be determined from the weight of the
precipitated double salt. A very small quantity of sulphuric
acid precipitates the barytes wbica remains in solution without
aettB^ upon the strmitian, and by entporating the filtered Kqmd
t» dryness, and decomposing the residue by sulphuric acid, the
latter earth may be obtained in the state of sulphate.

Silicated Fluate of Magnesia. — A transparent, yellowish,
gummy looking mass, easily soluble in water.

Silicated Fluate of Ahamna. — ^A clear colourless jeDy, wfaidi>
when dried, splits into fragments, and appears yellowish^ but
still retains its transparency. It dissolves slowly but completely
in water.

... Silicated fluate of glucina is readily soluble in water, and is
converted hy evaporation into a colourless s^rup, which finally
becomes white and opaque. Its taste is astringent, without any
admixture of sweetness.

SiUcated fluate ofyttria is insoluble in water, but dissolves in
«n excess of acid.

Silicated fluate of zirccnia dissolves very easily in water, and
may be obtained by evaporation in white crystals, which have
the lustre of mother-of-pearl. The solution becomes opaque
when boiled, but the greater part of the salt continues dissolved.

Silicated flwite of oxide of zinc is obtained by dissolving zinc
in the liquid aci<f. It is. extremely soluble in water, and is
deposited from a concentrated solution in crystals which are
generally equiangular three-sided prisms. The crystcds are not
altered by exposure to the air.

Silicatedjiuate qfoxidule of manganese is very soluble in water,
and crystallizes on cooling from a concentrated solution in long
tUn regular six-sided prisms. Sometimes it is obtained by
spontaneous evaporation in very short six-sided prisms, which
-mstinc|ly indicate the rhomboid as their basis. The crystals
have aj net perceptible tinge of amethyst red. It is converted
by ignition into the simple fluate without losing its crystalline

Silicated Fluate of Ojcidule of Iron. — ^When a solution of this
salt, prepared by dissolving iron filings in the liquid acid, is
allowjed to evaporate in a capsule of metallic iron, it shoots in

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128 M.Berzelim on Fluoric Acid, [Feb.

'blaish green caloured regular six-sided prisms; but the liquid is
converted into a dry mass so soon after it begins to crystalUze,
that, unless we operate upon large quantities, it is difficolt to
obtain the salt in perfect crystals. A second crystallization
renders the salt paler coloured and more regularly formed^ I
have remarked that all the coloured salts belonging to this class
have a deeper colour than Usual when crystallized from a solu-
tion containing an excess of acid ; but this difference in appear*
.ance does not seem to be accompanied by a corresponding
(difference in their composition.

Siiicated Fluate of' Oxide of Iron. — A semitransparent^ pale
'flesh coloured mass. It dissolves in water, and the solutionis
faintljr coloured.

.Siiicated Jluate of oxide of cobalt and of oxide of nickel are
easily soluble in water, and crystallize in forms which are
exactly similar to those of the salts of manganese and iron. The
crystals are rhomboids, but pass into regular six*sided prisms,
whenever they are in a situation to elongate themselves. The
.salt of cobalt is red ; that of nickel green.

Siiicated fluate of oxide of copper is easily soluble in water,
tfnd shoots by spontaneous evaporation in transparent blue
coloured crystals, which are more determinate!]^ rhomboidal than
the preceding, but which have still a decided tendency to
become six-sided prisms. The crystals effloresce externally
and become opaque when^xposed to the air, and tlieir colour, at
the same time changes to a light blue.

' The remarkable coincidence between the crystalline forms of
the greater number of the salts formed by the preceding isomo^-
phous metallic oxides, led me to suspect that they migfbt all
contain a similar number of atoms of water of crystallization. I
examined, therefore, the salts of oxidule of manganese and of
.the oxides of zinc, cobalt, nickel, and copper, and found that
they all contain a quantity ofwater of cmtalUzation whose oxy-
gen is seven times that of the base. The .fatiscerated salt iof
oxide of copper still retains a quantity of water whose, oxygenis
:£ve times that of the oxide of copper.

Siiicated fluate of oxidule of copper has^a red^colour, and
xlosely resembles the corresponding simple.fluate both in exter-
nal appearance, and in the decomposition which it sustains
througn the combined action of air and moisture. In a high
.temperature it melts, and loses its fluate of silica.

Siiicated Fluate of Oxide of JLeac/.— A transparent gummy-
looking mass, soluble in water, and possessing the peculiar
taste of the salts of lead.

Siiicated Jluate of oxide of cadmium is extremely soluble in
water, and crystallizes in long colourless prisms, which contain
.water of crystallization.

Siiicated Jluate q/ oxidule of tin, like the preceding, is very

Digitized by


1825 J M. Xerzeliiis an Fluoric Acid. 129

soluble in witter^ and crystallizes in long prisms ; but it is , par-
tially oxidized^ and decomposed during evaporation; and the
oxide thus formed precipitates in the state of a silicate. .

Silicaied Fluate of Oxidule of Chromium. — A green coloured
uncrystallizable transparent masis^ which deliquesces to a liquid
when exposed to the air. . * '

Silicatedjtuate of oxide of antimony is easily soluble in water
containing an excess of acid. By slow evaporation it crystal-
lizes in prisms, which, after being dried, rapidly fall to powder.

SiHcated Jtuate of oxidule of mercury may be prepared by
digesting newly prepared and still moist oxidule in the liquid
acid. It is by this means converted into a pale straw yiellow
coloured powder. The liquid, particularly when it contams an
excess of acid, retains a portion of the salt in solution, which it
deposits in small crystals when evaporated. The solution of
this salt has a weak metallic taste, and is copiously precipitated
by muriatic acid.

Silicated fluate of oxide of mercury is soluble only in an excess
of acid, and crystallizes by evaporation in small yellowish
coloured or almost colourless needles. When put into water,
this salt is partly converted into a yellow coloured insoluble sub-
salt; while the remaining portion is held in solution by the dis-
engaged acid. When ignited, gaseous fluate of silica is iq the
first' place expelled, and the nuate which remains undergoes
decomposition in the manner already described. The yellow
insoluble subsalt is blackened by ammonia ; but its colour is
again rendered lighter by the addition of water.

Silicated fluate of oxide of silver is a very deliquescent salt,
which may be obtained in white granular crystals from a solu-
tion c6ncentrated to the consistence of a syrup. A small quan-
tity of ammonia precipitates from the solution a light yellow
coloured subsalt, which, when added in excess^ it redissplyes,
and leaves a silicate of oxide of silver.

Silicated Fluate of Oxide of Platinum. — A yellowish brown
coloured salt, very soluble in water. When evaporated to a
tenacious syrup, and in this state digested in water, it leaves a
brown coloured subsalt undissolved.

Flu6silicates.—A shall hereafter discuss the different points of
view under which both the foregoing series of compounds, and
those which still remain to be described, rpay be regarded. At
present I shall merely add, that however much we may at first
feel disposed to do so, the silica cannot in these compounds, be
considered to act as an acid but as a base, and consequently
that the name o( silicate when applied to them implies an idea
which their nature does not authorise. The mineral kingdom,
however, furnishes us with examples of compounds in which a
fluate is actually associated v/ith a silicate, and for which there-
fore the appellation of fluosilicate would be sufficiently appro-
New) Sertes, vol. ix. k

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ISO M. Berxelim m Flume Acid, [Fbb«

priate. Thus the topaz consists of an atom of subfluate et
alumina combined witb nine atoms of silicate of alumina ; and
pycnite, of an atom of the neutral fluate combined with nin»
atoms of the silicate.

During the decomposition of the silicated fluates by the caus*
tic alkalies, particularly by ammonia, it is possible that other
fluosilicates may be produced, in which the relative proportions
of the fluate and silicate may vary with the different circum-
stances under which the compounds are formed. I have not
investigated this subject so minutely as it deserves, and indeed
I have confined myself to the decomposition of the silicated
fluate of lime by ammonia, as being that of which an accurate
knowledge is at present most interesting, because the prectr
pitates which result from this decomposition occasionally make
their appearance during the analysis of minerals. A mixture of
finely pulverized fluor spar and of ignited silica in the state in
which it is obtained from the decomposition of the fluate of silica,
was digested with muriatic acid in a closely stopped glass vessel,
from which no vapours of fluate of silica could escape. At the
^nd of 48 hours, the clear liquid was mixed with ammonia, and
the orecipitate was washed and ignited. Decomposed by suU
phuric acid, this precipitate gave ofi* gaseous fluate of silica,
which was received in carbonate of soda, and left 136 per cent*
of sulphate of lime. The alkaline solution was evaporated to
dryness in a moderate heat ; and the residue, being digested in
water, left 22*11 per cent, of silica. The remaining liquid wan
saturated with acetic acid, exposed to the air for 24 hours, in
order to ensure the dissipation of the carbonic acid, mixed with
ammonia, and precipitated in a stoppered vessel with muriate of
lime. The fluate of lime thus obtained weighed, after ignition,
78 per cent. The precipitate was composed, thereiore, of
neutral fluate of lime and of silica in the proportions requisite to
form with fluoric acid the liquid silicated fluoric acid. Whether
the silica actually existed in a state of chemical union is doubt-
ful, but it appears to be rendered probable by the fact, that tlie
neutral alkaline fluates are capable of dissolving siUea in a red
heat without undergoing decomposition^

Another portion of the same solution in muriatic acid was
mixed with muriate of lime, and decomposed by ammonia. The
precipitate, analyzecl in the same manner as the preceding,

Jrielded 160 per cent, of sulphate of lime = 62-25 per cent, of
ime, 19 per cent, of silica, and 66'67 per cent, of fluate of lime
» 18*04 of fluoric acid. It appears, therefore, to have been
composed of an atom of bisilicate and three atoms of fluate of
lime. The precipitate formed by ammonia in a solution of apo-
phyllite in cold nitrio or muriatic acid, and which many chsmists
have mistaken for alumina, possesses an exactly similar compo-
sition. If the mineral be dissolved with the assistance of heat.

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1825.] Col. Beaujoy's Astronamiedl Observations. 131

silicated fluoric acid is volatilized ; neither do we obtain tbe
oomponnd by evaporating the acid solution to dryness, beeauat
when a. solution of fluor spar and silica in an excess of mariatie
acid is evaporated, there remains nothing except muriate of limev
The double silicated salt^ of those bases from which ammonia
separates a portion of their fluoric acid would probably give
precipitates with that alkah, in which a different relation would
exist between the proportions of the silicate and fluate.

{To he contkiued*)

Article VII.

Astrommical Observations^ 1824 and 1826.
By Col, Beaufoy, FRS.

Bushey Heathy near Stanmore.

Latitude 510 37' 44.3// ^orth. Longitade West in time 1' 20*93^


Dee. 16. Immersion of Jupiter's first C 1 0^ (y 25'' Mean Time at Bushejr.

satdlite JlO 01 46 Mean Time at Qreenividi;


Jan. 4. Immersion of Jupiter's third < 12 37 01 Mean Time at Bushey.

satellite ^12 38 22 Mean Time at Greenwich.

Jan. 8. Immersion of Jupiter's fii«t 5 10 09 16 Mean Time at Bushey.

satellite 2^0 10 37 Mean Time at Greeanich-

Jan. 11. Immersion of Jupiter's third (16 35 19 Mean Time at Bushey.

satellite J 16 36 40 Mean Time at Greenwich*

Occultadon hy the Moon.
Bee 31. Immersion of | Pisces 6^ 26' 46^ Siderial Tfane.

Francis Baily, Esq. having favoured me with the nevr method
of determining the longitude by the culmination of the moon6,ad
stars ; together with a list of stars applicable to the purpose fof
the year 1826, the following observations were made at Bufthey

Transit over the Middle Wire in Siderial Time.

ffGemini 6k M' 46*46"

Jan. 4«-{ Moon's First limb 7 01 Q^B

7 11 4015

( g Gemini. . .

4-i Moon's Firs

(^ q Gemini..


Article VIII.

On a peculiar Class of Combinations. By Dr. F. Wohler.*

With the intention of preparing cyanuret of silver by th^
[^iprocal decomposition of cyanuret of mercury and nitrate o^

» Annalea dsr Fhysik.

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132 Dr. Wdhler on a [Feb.

'oxide of silver, I mixed pretty concentrated solations of the two
compoands : contrary to my e)cpectation, no precipitate fell ; but
after a few minutes there was deposited a number of somU white
crystals, whose quantity greatly exceeded that of the cyariiiret
of mercXiry which I had- employed. They were repeatedly
washed with water, and dried.

1 When these crystals are heated in a temperature above 212^,
they fuse in the first place into a transparent liqtiid; by and
bye they boil up and detonate vehemently, with a crackling
noise, and a purplish red coloured flame, closely resembling that
which accompanies the combustion of cyanogen. The residue
consists of cyanuret of silver, and, by continued ignition in the
open air, is converted into metallic silver. If the experiment
be performed in a glass tube, a quantity of mercury is also sub-
limed. Muriatic acid, poured upon the crystals, instantly disen-
gages hydrocyanic acid, and after the whole of the latter has
been expelled by the application of heat, there is given off a
strong odour ot chlorine : the liquid, evaporated to dryness,
leaves a mixture of the chlorides of silver and mercury. If a
solution of the crystals be precipitated by muriate of barytes,
and' if the filtered hquid be evaporated, there is obtained asaUne
mass, containing abundance of octohedral crystals of nitrate of
barytes. From the saline mass alcohol extracts cyanuret of
mercury. Consequently this crystallized substance is a com-
pound of cyanuret of mercury and nitrate of oxide of silver.*

This compound is very difficultly soluble in cold, but rather
co^piously in hot water, and as the solution cools, it crystallizes
in large transparent prisms, having the form of saltpetre. It
may be obtained in large crystals also by mixing hot solutions
of the cyanuret of mercury and nitrate of silver ^ the crystals
appearing as the liquid cools. Alcohol appears to dissolve it
in nearly, the same proportions as water, in boiling hot nitric
acid, it is soluble without decomposition. Alkalies precipitate
from its aqueous solution cyapuret of silver, which appears to
be mixed with subnitrate of oxide of mercury. Repeated solu-
tions in pure water produce a similar decomposition ; but only
to a very inconsiderable extent. . .

When these crystals are heated in a temperature rather below
212°, they give off water, and become white coloured and
opaque, without losing their original form. 100 parts, thus
treated, lost 7*6 parts of water.

To determine the quantity of silver, 1 gramme of the crystals
was treated with an excess of muriatic acid, and the mixture
was cautiously evaporated to dryness. The corrosive sublimate
being now expelled from the dry mass by ignition, there remained
0*32 gramme of fused chloride of silver. This is equivalent to
0'2688 gramme of oxide of silver, and consequently indicates
37*96 per cent, of nitrate of oxide of silver. The quantity of

Digitized by VjOOQ IC

1825.] .pectdiar Class of Combinations. 133.

cyainuret of mercufy was ascertained by dissolving 0*67 gramnier
of the crystals in hot water, and precipitating the silver by cyanic
acid.. The filtered liquid was then, evaporated to ; dryness, in-
order to expel the excess of cyanic acid, and the disengaged
nitric acid. 0*36 gramme of pure cyanuret of mercury remained
= 53*74 per cent.
Hence 100 parts of this compound consist of

Nitrate' of oxide of silver . .... 37*96 1 atom

Cyanuret of mercury 53*74 « 2

Water 7*60 8*


Here therefore we have a compound destitute of oxygen, and
analogous to the metallic sulphurets and chlorides, associated in
determinate proportions with another compound, which belongs
in the strictest sense of the word to the class of salts. As we
know that many bodies exert sometimes an electro-positive and
at other times an electro-negative action, and that many com-
pounds, which, by themselves, appear of an indifferent nature,
may assume either of these characters with reference to certain
other substances, it follows, that the compound here examined
must, in this point of view, be regarded as a saline coiiibination,
in which the nitrate of oxide of silver acts as the acid, and the
cyanuret of mercury as the base. The existence of water of
crystallization in the compound, which neither of its ingredients
in a separate state possesses, affords an additional argument for
ranking it in the class of salts. Berzelius, when he formed the
white crystalline compound of prussian blue and sulphuric acid,
was the first person wno discovered the existence of this class of

I now attempted to form other compounds, in which the
nitrate of oxide of silver would act as an acid when united with
metallic cyanurets.

Newly precipitated and washed cyanuret of silver was boiled
in a solution of nitrate of silver : it dissolved slowly, but com-
pletely. As soon as the temperature fell a few degrees below
the boiling point, there was deposited a large quantity of long
white shining needles, so that the liquid became converted
almost into a magma. They were transferred upon blotting-
paper and dried. This compound cannot be washed, for the
affinities by which . it is maintained are so feeble, that when
placed in contact with water, it is instantly resolved into pulve-
rulent cyanuret of silver, and the soluble nitrate. Hence in its
preparation it is necessary to employ a pretty concentrated

• Or 4 atoms of water, adopting Dr. Thomson's numbers, — Ecf.

Digitized by VjOOQ IC

134 Mr. Gray on some Species of Shelh [Feu .

solution of nitrfttd of silver. When h«ated, this compound
fuses, then detonsites with considerable energy^ and leaves
cyanuret of silver, which probably contains a minimum of cya-
nogen, it contains no water. If its constitution be analogous
i^rith that of the foregoing salt, it ought to be composed of

Nitrate of oxide of silver 1 atom «..•.. 38*79

Cyanuret of silver 2 61'21


It ought, therefore, to contain 70*76 per cent, of metallic
silver. This was confirmed by an experiment iu which 0*43
gramme of the salt, decomposed by muriatic acid, yielded me
0*387 gramme of fused chloride of silver, equivalent to 69*74
per cent of metallic silver.

I made many attempts, but without success, to form analo-
gous compounds by boiling other metallic cyanurets in a solution
of nitrate of silver. Cyanuret of nickel, treated in this manner,
instantly gave cyanuret of silver, and nitrate of oxide of nickel :
a similar decomposition took place with cyanuret of zinc. Prus-
sian blue occasioned the evolution of nitrous gas, and there was
obtained a solution of nitrate of oxide of iron, and a precipitate
consisting of a mixture of oxide of iron and cyanuret of silver.
Cyanuret of lead yielded a solution of nitrate and subnitrate of
lead, and a black coloured precipitate, which the application of
nitric acid proved to consist of metallic silver and white cyanu-
ret of silver. Cyanuret of copper, boiled in a solution of nitrate
of silver, gave a precipitate consisting entirely of metallic silver.
Cyanuret of palladium, similarly treated, sustained no alteration.

Article IX.

A List and Description of sortie Species of Sheik not taken Notice
of by Lamarck. By John Edward Gray, Esq. MGS.

(To the Editors of the Annals of Philosophy,)

GENTLEMEN, British Muteum, Jan. 10, 1825.

In the following list I have referred several species, which
have not been taken notice of by Lamarck, to his genera, and
have described some new ones that ar^ contained in the collec-
tion in the British Museum, where most of the species are exhi*
bited with the names^ here adopted, attached. . ; ;

Your obedient servant,

Digitized by VjOOQ IC

l^.J fioi tahA Ndtiee qfby Lamarck. 13{(

1. MoLLi3scA Conchifeha;

AspjSRGiLLUM Javanum, Lam. disco subperforato, tubvli
fimbrisB distinctis crassis^ Martini, t. 1^ f* 7.

A. Listeri. disco coafertissime perforato, tubulin fimbrisd coa-
fertis tenuibusy List. t. 548, f. 3. A. vaginiferuna, Lam, ? I
think that all the species of this genus will be found to have a
foliaceous mouth to their tube when they are perfect.

Mya Biiighami. Sphsenia Binghami, Turton.

Anatina« The shells of this genus always have a loose piece
in their hinge which is very much developed in A. Norvegica,
but is dictinctly to be found in A* Pratenuis and A, Myalis.

Anatina giobosa. Mya globosa, Wood, U 24, f. 4—6,

An. Nicobarica, Mya Kicobarica, Gmelin,

An.prtztenuis, Mya pnetenuis, Montague, t. 1, f. 2.

An, distofta, Myadistorta, Montague, t. 1, f. 1.

An. conmxa, Mya convexa, Wood, 1. 18, f. 1.

An. Norwegica. Mya Norweeica, Chemn. x, 1647, 1648.
Amphidesma corbuloides, Lam. Hist. 492.

An. membranacea. Mya membranacea, Dillwyn, 48.

Lute ARIA vitrea. Mactra vitrea, Ckemn. xi. f. 1959, 1960.

L.fragilis. Mactra fragilis, Chemn. vi. f. 236.
. M Acta A Campechensis. List. 304, f. 141.

M. squamosa. Solen squamosus, Montague.

£rVcina» Lam. Several of Lamarck's Crassatellis agree
with the character of this genus ; therefore I have removed them
M far as I have any grounds. The recent species of Lamarck is
a Cytherea.

iity. denticulata. Testa elongato-cuneata^ dentibus lateralibus

JEry. $triata. Crassatella striata, Lam. 483.

Ery. subangulata. Crassatella cuneata, Lam. 483?

Eri/.glabrata, Crassatella glabrata. Lam. 482.

Lry. ovata. Testa ovato-elongata, cardine in medio te sa?

Eri/. Australis. Mya Novae Zealandiae, Chemn. vi. f. 19, 20.

Ungulina. The only species of this genus that I have seen
appeicir to be too nearly allied to Amphidesma to be kept dis-

Amphidesma decussatum. Tellina decussata, Wood, t. 43,

Amph. cordiforme. Tellina cordiformis, Chemn. xi. f. 19,
41, 42.

Amph. variahile. Tellina obliqua. Wood, t. 41, f. 4, 5.
. Amph.f nitem. Mya nitens, Montague,

CoEBULA labiata. Mya labiata, Maton, Lin. Trans.

Pajndora glacialiss Testa semicircularis; cardine submedio;
mrgine dorsali recto.

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136 Mr. Gray on some Species of Shells £Feb*

. LiTHOPHAGiE. , The whole of the genera of this family appear
to have very great affinity to the Cardita, Cypricardia, &c. and
should be placed nearer to them in a natural arrangement as
well as the latter genera themselves ; but these genera appear to
be the most defective part of Lamarck's arrangement.

Petricola costata, Lam. Syst. Venus Lapicida, Chemn, x.
f. 1666, 1666.

Pet. divergens. Venus divergens, Gmelin.

Pet. nivea. Mytilus niveus, Chemn. viii. t. 82, f. 734.

Pet. suborbicularis. Mya suborbicularis, Montague.

Pet. hidentata. Mya bidentata, Montague.

Pet. rubra. Cardium rubrum, Montague.

Venerupis momtrosa. Venus monstrosa, Chemn. vii. f. 4Sl.

Yen. decussata. Mya decussata, Montague.

Tellina tenera. Macroma tenera, Leach.

LxTCiNA Childreme. Testa suborbiculata inequivalvis alba
subantiquata; tenuissime,radiatasubstriata:.long, 3unc. Brazil,
Humphrey s.noh. ZooL Jour. i. 221.

Luc. gibba. Tellina divaricata var. Chemn. y\. f. 130.

Luc.globosa. Venus globosa, Chemn.Yii.f.430,43l.

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