So METALLURGY OF CAST IRON. stoves generally run steadily [• for six weeks at a stretch, j and have been known to | run without interruption for j several months. This ' difference in their operation is due to this principle. Brick stoves now in use require the cold air to abstract heat from the bricks comprising the flues in the ovens, after the combustible or heating gases have all been shut off, and in the " iron stoves '' by reason of the iron pipes or flues through which the cold air passes, being separated from union with the gases; hence the iron stove can run steadily, whereas the1 brick stove runs only at J FIG. 14.. intervals. 18 Feet -MASSICK & CROOKK PATENT BRICK BLAST STOVE. HOT, which allows iron to be made more cheaply than where a temperature no higher than 1,100 degrees F. can be created, as with iron stoves. A further reason for this displacement is that the brick stove is less expensive, in matters pertaining to repairs and "shut-downs," to keep a furnace naming steadily, also in giving more K;IS for use under boilers, etc. than iron stoves.