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THE POPULAR SCIENCE MONTHLY. 



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 con- 

 struction 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 con- 



Fig. 38. An Early French Coke 

 Blast-Furnace. 



Fig. 39. Section of French Coke 

 Blast-Furnace. 



struction. 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, 18G3, was 



