Extraction of Platina in Russia. 
237 
ous organic salts, that by means of tannin all of them that 
have not been absorbed, may be separated from the fluid and 
other contents of that viscus. I would also add, that pure 
tannin might be administered with success as an antidote 
against several of the vegetable poisons. 
From the above it may be concluded : 
1. That pure tannin, or substances containing it, forms very 
abundant whitish precipitates which are in the state of hy- 
drates, and almost insoluble in cold water, when added to 
solutions containing vegetable organic salts. 
2. That these compounds, whose insolubility permits the 
extraction of very minute proportions of the vegetable alka- 
lies, are composed of one atom of base and two of tannin, 
and must hence be considered as bitannates. 
3. That this property of tannin leads to very useful appli- 
cations, as well in the extraction of the vegetable alkalies, as 
in the detection of them when criminally administered. — 
Journ. de Pharm. 
ART. XLVIII.-^-EXTRACTION OF PLATINA IN RUSSIA. 
By P. Soboxewskoy, Chief Engineer of Mines. 
The discovery of Platina in the Russian empire, forms a 
remarkable epoch in the history of this metal; in 1822 it was 
found in the gold washings of the Ural, but the discovery of 
mines of this metal was not made till 1824. Since that time 
the product has increased from year to year, and at present 
is estimated at upwards of 110 pouds per annum. 
From the middle of 1824, to January, 1834, nearly 476 pouds 
of pure platina have been obtained, of which 400 have been 
coined, and the remainder used for assay vessels, &c. 
The platina of Ural has hitherto been only found dissemi- 
nated through sand. The richest locality is in the mines of 
