From the above, it refults, that a folution, evaporas-
tion, alluvion-, and depoiition, all exift in: this mine
its fituation is ah undulated hill;- which,. viewed from-
the neighbouring mountains, feems almoft a plain ; its-,
form: is regular, and. one may go round-it in about, four
or five hours. The ore forms an uninterrupted:ftratum,.
whofe thicknefe varies from three-feet to ten*, and is covered
with a coat of whitiih calcareous rock, from two-
to fix. feet thick. I now proceed to their method of.
working this mine, where every one is at liberty,to dig
at pleafure, and tranfport it by land or water,, without,
being fubje^b to duties o r any formalities,- The people
being generally ignorant, and carrying away whatever
comes uppefmoft,. often take*ore; which has its matrix,
of* quartz, and-is of a brittle kind, full o f cracks ; but.
the iron* mailers*, who are the purchafers, are; more
verfed, and know what* to buy, and what to reject,. It is-
generally allowed, that no iron in* Europe is fo eafy to>
fufe, or fo foft as that.of Somorroilro,. When the ore
is firft taken out of this mine, it has the- colour o f bullis.,
blood, and when wetted becomes purple greats quantities
are carried away by water, to the neighbouring,
provinces, where they fufe it by itfelf, or mix it. with,
ore of their own, which generally yields a harder iron.;
I fhall only fpeak of their procefs with-that. ore. which .is
fufed without any mixture.
The firft operation* is-to roaft it (a) in the open-air, by
piling ftrata alternately of ore, and wood, in order to
divide the ore; repel the moifture, and diminiih its
weight, that it may be more eafily fufed, and the fcrru.-
ginous parts foparated from the flag ; when it is-fulficiy
ently roafted; they put it in the forge, with the due pro*
portion of charcoal, and when it appears to have fufed;
by leaving on the hearth, a mafs of four or. five arrobes,.
they lay hold of it with tongs, and place it on an anvil,
under an immenfe hammer, o f about feven hundred to
a thoufand pounds weight, and there by force of blows;
and moving it about, they fquare it, and reduce it into
bars ; The numerous fparks which fly off from the blows
o f the hammer, are no more than the fcoriae of the metal.
The bar thus- ihaped, may be doubled or lengthened
in adefs forge, if they pleafe, and even beat'cold as if
it was filver. In this manner the ore is fufed-in a few*'
hours, and the bars formed, and fold*to the blackfmiths.
(«)■ No-general’rule can be given, .concerning.the-duration, ordegEee of fire, for this-
putpofe, th'efe being various, according to the difference o f the ores; a few days, or even
hours, is fufficient for- fome ores, while, others, futh as the ore of Rammelfburg, .require
that it fhould be continued fbr feveral months— Shlutter enumerates five methods o f roaft-
ing ores ; v iz .-
Firft, By conflruffing a pile o f' ore and fuel,' placed alterhately in- ftrata, in; the open a ir ,.
Secondly, By confining fuch a pile within walls,- but without a roof.1
Thicdly, By placing.the pile under a roof, without lateral walls. ■
Fourthly, By placing the pile in a furnace, confiding of walls and roof.'-
Fifthly, By roafting the ore in*a Teyerbatory furnace,- in which it mu ft be continually ftir- -
• red,- with an iron rod...
Formerly'