therefore, requires frefli experiments. Nitric acid dif- 
folves it, throwing off red vapours. The muriatic acid 
diffolves it alfo ; this fol'ution cryftallizes very difficultly. 
The alkalis, and even water, precipitate the metal from 
this folution. It is laid that it mixes with other metals. 
Hut all that is known of this metal, is at prefent very 
uncertain : it is not even known, perhaps, at all in a 
pure ftate; for Bergman is doubtful whether it can be 
completely feparated from the iron it contains. To ob¬ 
tain manganefe as free from iron as poffible, Richter re¬ 
commends the following procefs : A faturated folution 
of fulphat of manganefe is to be mixed with a folution 
of tartarit of potafh, and the mixture placed on a find- 
bath. In the courfe of a few minutes, a white precipi¬ 
tate is formed, which increafes in proportion as the fluid 
is evaporated. When the evaporation has been carried 
fo far on, that the fulphat of potafli is difpofed to 
cryffallize, the clear liquor is to be decanted off, and the 
precipitate well edulcorated with a fmall quantity of 
water. The water ufed for edulcoration, together with 
a frefli quantity of the tartarit of potafli, is to be added 
to the liquor, in order that any manganefe which they 
contain may be precipitated. The precipitate, which is 
a pure tartarit of manganefe, may be decompofed by a 
flrong fire, and fubjedied to the ufual procefs for obtain¬ 
ing this liibftance in its metallic ftate. 
The properties of the native oxyd of manganefe are, 
however, better known. The accurate experiments of 
Scheele, and thofe of Bergman, Gahn, Rinman, Engef- 
troem, Ifleman, La Peyroule, and Fourcroy, have thrown 
great light upon the properties of this metallic fubftance. 
The pure oxyd of manganefe is pulverulent, loft to the 
touch, and foils the fingers. Melted under the blow¬ 
pipe, with microcofmical fait, a tranfparent glafs is ob¬ 
tained, of a bluifli red colour; if left to grow cold and 
melted again, flowly, the colour difappears; melted afrefli 
with the outward flame of a blow-pipe, the colour may 
be made to come and go alternately. 
By heating the native oxyd alone in the pneumatic 
apparatus, very pure oxygen gas is obtained. It is this 
oxygen or vital air alone, which can be ufed to advan¬ 
tage by patients whofe diforders require the adminiftra- 
ticn of this fluid. It is to be remarked, that in diftilling 
the native oxyd of manganefe, in order to obtain vital 
air in a very pure ftate, the retort mull; be completely 
filled with this fubftance, fo as to allow no atmofpherical 
air to remain in the retort. It is in this way that the 
vital air intended for the ufe of the lick, or for the com¬ 
petition of water, ought to be prepared. Without this 
precaution, a confiderable quantity of nitric acid will 
be formed, or a mephitic relidue produced, which Hops 
the combuftion of the hydrogen gas, and renders it necef- 
fary to empty the receiver. After the operation, a grey 
matter remains in the retort; this, if expofed to the air, 
will attraft oxygen, and become of the natural black co¬ 
lour of the oxyd. By diftilling oxyd of manganefe with 
charcoal, the produfl is carbonic acid gas. The action 
of other combuftible bodies with it is not known. 
Gmelin, it is faid, lucceeded in forming a mixture of 
oxyd of manganefe and fulphur. If fulphuric acid be 
poured on oxyd of manganefe, with the help of a very 
gentle heat, oxy r gen gas is difengaged. See on Oxygen 
Gas, page 193, for the manner of the operation. If a 
larger quantity of the acid be poured in, the oxyd dif- 
folves: the lolution is coloured, but is deprived of co¬ 
lour by the addition of a combuftible body, as fugar or 
honey; it furnifhes a tranfparent fulphat of manganefe 
in parallelopiped cryftals. This fulphat is decompofed 
by fire, and gives out oxygen gas. The alkalis leparate 
an oxyd from manganefe, in form of awhitiffi gelatinous 
matter, which becomes brown by expofure to the air: 
this change of colour is owing to the ablorption of 
oxygen. 
The oxyd of manganefe is not attacked by the nitric 
acid, becaule the acid finds the manganefe already oxy- 
S T R Y. 
dated ; nor is it much aflefled by the fuming or hot acid 
of Boyle; but, by the addition of a combuftible body, 
as fugar, honey, &c. the diffolution is complete. This 
fait has not yet been obtained in cryftals. Alkalis pre¬ 
cipitate from its lolutions a.white oxyd, foluble in acids, 
which, when heated, becomes black, and is oxydated 
ftill more. Bergman thinks that this metal has a greater 
affinity with falts than moll metallic fubltances ; he places 
it in his table, near the top of that column which con¬ 
tains the eledtive attractions of acids. The muriatic 
acid likewife diffolves manganefe; and, when digefted, 
it feizes on the o-xygen, and pafies in vapours through 
the water: this is what is called oxygenated muriatic acid. 
See the feCtion on that acid, page a 18. Muriat of man¬ 
ganefe is decompofed by alkalis alfo. 
• Fluoric acid forms with oxyd of manganefe, a fait fo¬ 
luble with difficulty ; but, by deeompofmg the fulphat, 
nitrat, or muriat, of manganefe, with the fluat of ammo¬ 
niac, a fluat of manganefe is precipitated. The carbonic 
and acetous acids have little effedt upon the oxyd of 
manganefe. Its adtion with terreftrial fubftances has not 
been fully examined. Combined in a large proportion 
with gold and filver, manganefe renders theie metals very 
brittle. It precipitates filver from acids in a ftate nearly 
approaching to the metallic. Mercury and manganefe 
do not enter into combination. Manganefe precipitates 
mercury from its folution in acids; oxyd of tnanganele 
has no adlion on the oxygenated muriat of mercury; 
but, diftilled in the proportion of two to one with ordi¬ 
nary muriat, it converts the mercurial muriat into the 
oxygenated. During its diftillation with cinnabar, ful¬ 
phuric acid gas, and fluid mercury,,are difengaged. Lead, 
according to Gmelin, unites with great difficulty to man¬ 
ganefe. The properties of the lead, by this admixture, 
are but little changed. Copper unites, by repeated melt¬ 
ings, with manganefe, and forms with it a white malle¬ 
able metallic mafs. Manganefe does not precipitate it 
from its folution in acids. Arfenic forms a metallic mix¬ 
ture by melting it in dole vellels with manganefe. In 
diftillation together, the white oxyd of arfenic pafies over 
unchanged. 
The oxyd of manganefe combines very well with alka¬ 
lis; it is revived by combination with ammoniac. In 
this combination a peculiar gas is dilengaged, which ap¬ 
pears from the difeovery of Berthollet to be azotic gas, 
and that the hydrogen of the ammoniac combines with 
the oxygen, and takes it from the manganele, which is 
thus reduced, and becomes white. 
Scheele has given the name of cameleon mineral to a 
combination of potalh and oxyd of manganele in the dry 
way : Reduce the oxyd of manganefe to powder, and mix 
it with the potafli; put the mixture into a crucible, and 
urge the fire. The produdt is a kind of vitreous frit, fo¬ 
luble in water. Put an equal weight of this matter into 
two glafles, and pour hot water upon one, and cold water 
upon the other; and you have at the fame time a folu¬ 
tion of a red colour in the cold water, and'of a beautiful 
green in the hot. The fame matter in the fame water at 
different temperatures will aflume various colours : this 
arifes from the feveral degrees of oxydation ; for, at the 
end of four and-twenty or fix-and-thirty hours, all the 
liquors are as colourlefs as water, and the manganefe is 
equally precipitated in both glafles. The fame pheno¬ 
mena arife from nitrat of potafli mixed with oxyd of 
manganele. The nitrat is decompofed by caloric; and 
the oxyd with the potafli form a foluble mafs, of a dark 
green colour, fliewing the fame properties as mentioned 
above. 
Borax, melted with oxyd of manganefe, afiumes a 
brown or violet colour. Muriat of ammoniac, diftilled 
with this metallic oxyd, affords ammoniac in part de¬ 
compofed ; in which procefs water is formed by the union 
of hydrogen, one of the principles of this fait, with the 
oxygen of the oxyds, while the azot, or the other prin¬ 
ciple of the ammoniac, is difengaged in the aeriform 
ftate. 
