from 6 § 
The ore being thus analysed, it may be submitted to 
the common processes in the large way* 
Roasting . If the ore on being pounded and exposed 
to a full red heat, gives out any sulphureous vapour, it 
should be roasted, by placing it in wedge-like heaps, and 
leaving openings for a fire. The ore thus roasted with a full 
red heat for 10 or 12 hours, will part with nearly all its sul- 
phureous and watery parts. But unless it be stratified with 
charcoal dust, the current of air will oxygenate it, and ren- 
der it still less metalline than before, and cause it to require 
a greater charge of charcoal, and a longer time in the smelt- 
ing furnace. Mr. Mushet proposes roasting the ore in a 
separate furnace, but this would appear here, a plan too 
complicated. 
The common method as detailed by Dr. Aikin, is as 
follows. 1 Chem. diet. 596. 
The first process that the iron-stone undergoes after it 
has been broken into pieces not larger than an egg, is roast- 
ing. This is sometimes performed in cup-shaped kilns, 
the bottom being occupied by lighted coals and the kiln 
then filled up with ore, which by the time that the fuel is 
consumed is found to be sufficiently terrified. The most 
usual way however of burning iron-stones is the follow- 
ing. Upon an oblong piece of firm and level ground is 
laid a bed of small coal from four to eight inches in thick- 
ness ; upon this is placed a stratum of iron-stone compo- 
sed of pieces as nearly as possible of the same size, and 
from 18 inches to two feet thick : the upper surface of 
this is then rendered more compact by filling up the inter- 
stices with smaller pieces of ore. Upon this rests a layer 
of small coal not more than two inches thick, and on this 
as a base, is reared a gradually diminishing pile of ore so 
as to resemble the ridge of a house ; finally, the whole ex- 
ternal surface receives a compleat covering of small coals 
and coal dust- The pile is kindled by applying burning: 
I 
