hoops; the lower portion remaining quite as massive as had been customary.
The next stage in the evolution made the whole furnace a frustum of a cone pierced at the base by four or more arches, that portion above the arches being hooped. The next change in construction consisted in casing the whole furnace, sustaining piers as well as the part above, in boiler iron. This construction was followed by the removal of the piers altogether, the upper conical portion of the furnace being built of cut stone hooped with iron and supported on cast-iron columns. Fig. 38 is an elevation and Fig. 39 a vertical section of one of the earlier furnaces of this construction.
| Fig. 38.—An Early French Coke Blast-Furnace. | Fig. 39.—Section of French Coke Blast-Furnace. |
There were three such furnaces built at Hyanges, department of Moselle, France, prior to the year 1849 (probably in 1845). These furnaces were forty-six feet high and sixteen feet in diameter at the "boshes" and eight feet at the top. They were built expressly for the use of coke, and, according to Overman, they "worked admirably."
The study of the construction and operation of such furnaces as these doubtless had its influence in determining the details of the Clinton Furnace of Graff, Bennett & Co., of Pittsburg, already referred to as having been the first to use "Connellsville coke" with success. This furnace, which I visited in January, 1863, was
