: =e. eee ele eee 
Zoology. 
by the preceding process, is an objection, though it has the advantage 
of being applicable on a lar rger r scale, and requires no fuel but for the 
distillation of the amalgam; it is the old method. 
Third method. The finely divided ore is roasted with common salt 
as in the first method, then placed in a vat with salt and water; the 
silver is thus converted. into a chlorid, which is) stirred up and then 
passed into a smaller vessel, to collect: the heavy ae ged particles, and 
thence into a'third, where pieces of copper cause a decomposition of 
the chlorid of silver, the pure metal being pehieigietad and a’chlorid of 
copper formed ; this is passed into a fourth vessel where fragments of 
iron cause a precipitation of the c copper. By this process, which is 
mingles the copper—of which there is generally a considerable quantity 
Iso.saved 5 it is as yet employed but on a small scale at Sanche, 
f 
2 
Fourth method. ‘The fine powder from the pounding | mills is mixed 
with lime, scoria, iron-and oxyd of lead (litharge), and then thrown into 
a smelting furnace with alternate layers of coal; a portion of the sul- 
~phur combines with the oxygen of the lime aad litharge, and with the 
iron, passing off in thegfirst two cases as sulphurous , acid gas, and in 
the third — sulpheret of iron; whilst the remainder, uniting with 
‘the base of the lime, forms sulphuret of calcium; this with the scoria 
forms a melted mass, which falls to the bottom of et furnace, and 
flows off at a lateral orifice. By this process the silver is reduced to 
the metallic state, but as the amount is small and patie > throw 
the mass, it would, to a considerable swat op be carried off by the sco- 
ria and lost; hence the lead is employed, to collect the particles of 
silver and thus’ lon an —_ which flows oy at the lower pegs of 
‘the smelting furna 
This alloy is now ncetnned in 1 sballow basin: fatiencnte and whilte in a 
melted state, strong currents of air are forced over its surface, which 
po rn the lead and with it all the baser metals, and the silver remains 
ure ; the, dross being blown away by the draughts Of air. This i is the 
St procéss ss for the rich ores, and in the works of the English mining 
company, is, I believe, always employed for their reduction 
The silver is frequently alloyed with gold, whichy when of sufficient 
value, is ‘separated at the mint, and after deducting ee the re- 
mainder is returned in coin to the owners. 
itt. Zoo.oey. 
of re Iguanodon, pening enabled the author to” 
evidence us to the structure of the maxillary organs that gi 
herbivorous reptile, the see of his investigations are gir ge 
he mn The first memoir on the teeth of th 
ee ay Eyeing neg te for 1 
ee af 8 
” 
dition in which 
ate uy fd 
