iran News, ) The New Metal Gallium. 167
April 27, 1877, — " fo pees ——
tare sufficiently distin& for gi nature to be determined.
This salt has been prepared by neutralising with ammonia
T H E C H E M I C A L N E Ww S. an acid solution of sulphate of gallium, and allowing the
liquid to evaporate slowly. There could not be in it any
other alkalies than ammonia and traces of soda. The
alumina ought to have been separated by repeated treat.
ments with sulphuretted hydrogen in the presence of acid
acetate of ammonia and salts of zinc,
The following fa&s relate to the small crystals presented
 to the Academie des Sciences on December 6,
1875 1—
Ballium alum is colourless and limpid. It is soluble in
cold water and in weak alcohol. A concentrated solution
becomes slightly turbid on boiling, and clears completely
on cooling. When the solution is very dilute the boiling
causes the formation of an abundant white precipitate ;
:his is probably a basic salt. If filtered when hot only
traces of gallium remain in the liquid. The precipitate
may then be washed over the filter, at first with boiling,
then with cold water, without sensible loss of gallium, but
if it is left in contac with the mother-liquor it is com.
pletely re-dissolved when cooling. The dilute solution of
zallium alum does not become turbid on boiling if a little
sulphuric acid is added. A certain quantity of acetic acid
produces the same effet; doubtless an equilibrium is then
maintained between the acetate and the sulphate of am.
monia, and the small portion of sulphuric acid set at
liberty holds the sulphate of gallium in solution. Unlike
acid acetate of ammonia, gallium alum behaves itself
with heat and in the cold exactly like the neutral sulphate,
Gallium alum crystallises into cubes having o&ahedric
faces, and into o&ahedra with cubic faces. These crystals
present exactly the aspe® of common alum; their solu-Hon,
 if slowly evaporated, behaves under the microscope
just like the known alums, Placed between two Nicol
orisms gallium alum does not ac upon polarised light,
With respeé to the phenomena of supersaturation gallium
alum behaves as a veritable isomorph of the other alums.
A small crystal was kept for some time under a layer of
water, in order to deprive it of the crystalline germs
attached to its surface. It was afterwards laid in 5 slightly
supersaturated solution of alumino-ammoniacal alum, [It
grew immediately therein, and determined the crystallisation
 of the liquid.
I have recently proved that gallium alum ig produced
when solutions of sulphates of ammonia and pure gallium
are mized. If protected from atmospheric dust the liquid
remains clear, but it crystallises as soon as it comes in
contact with a trace of common alum. A supersaturated
solution is equally well obtained if slightly acid gallium
alum is concentrated in the heat. If, as seems certain,
there is no error in the nature of my gallium alum and
ammonia, the existence of this combination fixes the
atomicity of ‘the new elemert, and attributes to its oxile
the same chemical fun&ion as that of alumina, The oxide
of gallium will, then, be described as G2,0;, and the
chloride probably Ga,Cl. Besides, all the properties
above described agree in classifying the oxide of gallium
among the sesqui-oxides, Up to the present time I have
observed nothing which indicates several degrees of
oxidation of gallium,
VII. EXTRACTION AND PURIFICATION OF GALLIUM,
As soon as the principal chemical characteristics of the
new element were known to me, I tried to discover the
most economical and rapid method of extracting and
purifying it.
The following is the method I adopted for the treatment
of several hundred kilogrammes of raw material :—The
crude blende, reduced to powder, is dissolved by the aid of
heat in aqua regia, containing 4 or 5 parts of hydrochloric
wid tox of nitricacid.® An excess ofaguaregiaand an excess
of blende are alternately added, so as not to leave any nitric
acid inthe final liquid, whilst the ore is completely attacked.
.nloric acid will be sufficien;

VI. Savrs oF GaLrium,
THE 10 centigrms. of pure gallium obtained at the end of
April, 1876, were almost immediately sacrificed in trying
to determine the equivalent, for which, moreover, I have
not yet found numbers sufficiently concordant, It has,
therefore, been impossible for me at present to utilise, in
the preparation of its compounds, those relatively large
quantities of gallium which I have obtained. I have only
employed for this purpose the few milligrms. of the new
metal produced from the earliest operations, so I shall
only describe, and that very summarily, a small number
of gallium salts. All the compounds of gallium which I
have examined are colourless, ’
I. Chlovide.—Chloride of gallium is very soluble in
water, and deliquescent. "If its solution is evaporated and
carefully dried, the residue attracts moisture from the air
and liquefies. The syrupy solution thus obtained is clear,
and does not become turbid if diluted with a very small
quantity of cold water. A larger quantity of water, however,
 causes the formation of a copious white precipitate
(doubtless an oxychloride) which falls quickly to the
bottom of the vessel, and which dissolves only slowly in
dilute hydrochloric acid in the cold, but more rapidly by
the zid of heat. In researches on gallium this property
must be borne in mind, otherwise there is a risk of the
rare metal being left in the residues precipitated in the
cold by weak hydrochloric acid. In order to extract all
the gallium from an insoluble produ the latter must be
boiled with water strongly acidulated with hydrochloric
acid. In my earlier researches I often failed to detec the
presence of the new metal in consequence of the great
difficulty in separating it from the masses of insoluble
residues with whichit had become incorporated. If a very
small quantity of hydrochloric acid is added to some dried
chloride of gallium the latter is dissolved in cold water;
this dilute solution becomes turbid when hot, and grows
clear again on cooling. If a slightly acid solution of
chloride of gallium is dried at a gentle heat it yields
crystalline needles and leaflets, which ac strongly upon
polarised light.
2. Sulphate.—This salt is very soluble in water, The
concentrated solution is syrupy. It is not deliquescent.
When very neutral it decomposes on boiling; very little
gallium remains in the liquid provided the latter is sufficiently
 dilute. When cold the precipitate is completely
re-dissolved. Sulphate of gallium is soluble in alcohol at
Go per cent. It is insoluble in ether, By slow evapora.
tion, or on the cooling of a concentrated solution, it
crystallises in the form of leaflets, soft to the touch,
having a pearly appearance, and being sometimes grouped
in stars or shining masses. If evaporated and dried until
the evolution of white sulphuric vapours almost ceases, an
acid sulphate of gallium does not lose its solubility in
water nor in weak alcohol; a certain time is, however, required
 for the completion of the solution.
3. Alum.—I have obtained a well crystallised salt, which
to all appearance is ammonio-gallic alum. The quantity
at my disposal has not been sufficient to enable me to
analyse it nor to measure jtg angles, but its characeristics