227 
Iron± 
much stirring, and frequently pressing them together, they 
cohere into a pulpy mass ; and being gathered into pieces 
of a convenient size, are carried under rollers, where, after 
( passing through four pairs, in succession, of a gradually 
diminishing guage, they are produced into plates seven or 
eight inches wide, and three feet or more in length. Con- 
j siderable quantities of matter are squeezed out in die roll- 
ing, which principally consist of a vitreous kind of oxyd. 
This is, for the most part, to be referred to the action car- 
ried on in the furnace : but some portion of it is, in all 
probability, created by the combustion of small pieces of 
fluid metal, which, engaged amongst the particles of the 
| puddled mass, are hurled through the air in a state of vivid 
inflammation, by the compressive violence of the rollers. 
The total loss dius sustained is estimated at from l-6th 
to l-7th. The plates obtained by this treatment have a 
very incompact appearance : and if attempted to be work- 
ed in the state they are then presented under, would 
crumble almost wholly into small granulated lumps. To 
impart to them the necessary closeness and solidity, they 
are again heated in another kind of furnace, and beaten 
forcibly with a heavy hammer, which is raised by ma- 
chinery. 
Previously to being thus treated, they are broken up 
into cakes of small size, and placed upon circular slabs of 
stone from 8 to 12 inches in diameter. The size of the 
cakes is in a great measure determined by a particular ef- 
fect of the last pair of rollers' that they are passed through ; 
ribs, of a diamond shape, girding either one or both of 
them, on the whole extent of their surface, which leave a 
deep indentation on the plates, so as to render them easily 
frangible in that direction. The height to which these 
cakes are piled on the circular slab just spoken of, is gene 
rally about 12 inches ; and when so prepared, they are 
placed on the hearth of a reverberatory furnace, which 
