ON THE TRACK OF THE " OLD MEN." 
225 
wrought iron called the hearth eye. The tin and charcoal are laid 
in the castle, stratum super stratum, in such quantities as are 
thought proper; so that from eight to twelve hundredweight of 
tin, by the consumption of eighteen to twenty-four sixty gallon 
packs of charcoal, may be smelted in a tide of twelve hours' time. 
Those bellows are not only useful for igniting the charcoal, but 
they throw in a steady and powerful air into the castle ; which, at 
the same time that it smelts the tin, forces it out also through a 
hole in the bottom of the castle, about four inches high, and one 
inch and a half wide, into a moorstone trough, six feet and a half 
long [in the original it says six and a half feet high, but this is 
obviously a misprint] and one foot wide, called the float, whence 
it is laded into lesser troughs or moulds, each of which contains 
about three hundred of metal, called slabs, blocks, or pieces of tin, 
in which size and form it is sold in every market ii\ Europe ; and 
on account of its superior quality is known by the name of Grain 
tin, which brought a price formerly of seven shillings, that is 
further advanced, the last two or three years, to ten or twelve 
shillings per hundred more than mine tin is sold for, because it is 
smelted from a pure mineral by a charcoal fire ; whereas mine tin 
is usually corrupted with some portion of mundick, and other 
minerals, and is always smelted with a bituminous fire, which 
communicates a harsh sulphureous injurious quality to the metal." 
Such is a description of the furnace of the stream work 
blowing-house, in use in Devon and Cornwall one hundred years 
since, and which was introduced by the Germans into this country 
over three hundred years ago. 
George Agricola, a physician and eminent authority on mining 
matters, who was born at Glauchen in 1494, wrote several books 
on metallurgy, and on the working and management of mines. 
It is interesting to note how very old the bulk of the mining 
operations as carried on at present are. Our machinery of to-day 
is improved, and we possess the advantage of steam ; but water- 
power mines are very similar in many respects to those in 
operation hundreds of years since. 
A German edition of Agricola's great work was published at 
Basel in 1621, and another in Latin at the same place in 1657. 
Both are profusely illustrated from the same blocks, with spirited 
and well-executed engravings descriptive of mining and smelting 
operations. 
Some of the impressions are marked with a monogram composed 
of the letters E.H.M.D. with a dagger, the cypher of Eodolphus 
Manuel Deutsch, an engraver who flourished about 1548. 
