METALLURGY OF CAST IRON.
out a crucible. The staging H as shown is placed any height to suit the operator. The cupola has four tuyeres, two inches in diameter. In charging to run a uvheat," have the coke ten inches above the tuyeres;
if coal, seven inch-es above the __ tuyeres. The fuel /£__., s li o u 1 d not 1) e =, much larger than :~— double egg size, and the bed well burned up before the first iron is charged. On the bed, place fifty to one h u n d red pounds of iron, which, if pig iron, should be broken in lengths of from • five to eight inches. If the pigs were too strong to break by sledging, etc., one-inch holes could be drill e«j a n d a. ;. | )U i it'll used to fracture. Should more than 100 pounds require melting, charge twenty pounds of eoke or cord, and on this one hundred poundsnf iron, am! so continue as long as the cupola works all right. With a
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< Kl < 11 1) It K\e to use a small cupola for crucible melting also, I have studied to the point of combining the two, and as a result present the following original device or small cupola, as seen in Fig. 69, next page. This cupola can be erected in any out-of-the-way place, or by the side of a regular " heat " cupola, so that the flue A can be attached to head off the sparks, etc., when used as a cupola, without risk of setting anything on fire, should there be any danger of this; if not, then, the cover B could be dispensed with and the flame, etc., permitted to pass out at the top. B is a cover made of cast iron, and having prickers on the under side for the purpose of holding a daubing of clay to prevent the heat of the furnace burning the cover. Trie handle D is for convenience in lifting the cover on and off when desiring to change or takeus that