5. Miscellaneous Expenses and Superintendence. — Aside from
the allowance made in each department of the work for the
above purposes, it will be found in practice that a consider-
able additional sum is required to cover errors in construction,



i



\



STALL ROASTING. 105

blacksmith work, and various incidentals, as well as general
superintendence, amounting in a case similar to the above to

$211.00
Cost of 4-inch brick arch to cover main flue 187.00

$848.00

Summary.
Excavation for foundations $157.00

Materials for mason-work 740.60

Labor in building stalls 1,612.10

Rail roads 441 . 00

Miscellaneous and superintendence 848.00

Grand total $8,298.70

Uneven ground, bad weather, and other unfavorable
causes may increase this sum to a considerable extent, but the
figures given will be found safe under ordinary circumstances
and with strictly judicious and economical management.
The calcination of matte in ore stalls of the pattern just
described is by no means impossible, the principal difference
between its treatment and that of ore being the increased
quantity of fuel required — about three times as much. A con*
siderable proportion of the matte will be fused during tbe
operation, and another large fraction scarcely affected by the
process ; so that from three to four burnings are required to
effect any reasonably perfect desulphurization.
This practice cannot be recommended, as much better
results are obtained by providing the stalls with grate-bars, and
preventing the radiation of heat from the surface by means of
an arched brick roof, as described in the succeeding chapter.
THE STALL BOA8TING OF MATTE.
