314 THE POPULAR SCIENCE MONTHLY. 



THE DEVELOPMENT OF AMERICAN INDUSTRIES 



SINCE COLUMBUS. 



II. IRON MILLS AND PUDDLING-FTTRNACES. 



Br WILLIAM F. DUKFEE, Engineer. 



IN these days of steam-engines, railways, and steam navigation 

 telegraphs, telephones, and electric lights it is hard to un- 

 derstand a civilization which in literature and the fine arts has 

 not been surpassed, yet had none of the above-named essentials of 

 modern fast living and rapid work, and which possessed no better 

 methods of manufacturing iron than those already described. 



It will be evident to the most superficial observer that these 

 methods were not calculated to produce merchantable bar iron 

 either rapidly or cheaply, and this fact would be the more manifest 

 as the bars or rods decreased in size. Therefore, as the require- 

 ments of trade were mainly for bars and rods of moderate dimen- 

 sions, from which to forge nails, draw wire, and manufacture 

 multitudes of the smaller articles of hardware for which the set- 

 tlement of new countries had created a growing demand, nothing 

 could have been more natural than that the efforts of mankind 

 to meet the requirements of the time should have resulted in the 

 invention of the " slitting-mill." We have no precise information 

 as to the date of this invention, and none whatever respecting its 

 inventor. It is very probable that the slitting-mill was invented 

 in Sweden, and carried thence into Germany, Belgium, and Eng- 

 land, whence it found its way to the colony of Massachusetts 

 Bay, where the first " slitting-mill " used in America was put in 

 operation some time prior to 1731. Swedenborg, in his De Ferro 

 (1734), speaks of " slitting-mills " in Sweden, Germany, Belgium, 

 and England, but does not refer to their origin, and says nothing 

 whatever of grooved rolls. Slitting-mills were introduced into 

 England as early as 1697. 



A " slitting-mill " comprises two principal mechanisms, which 

 are well illustrated by Fig. 17, which, together with Figs. 16 and 

 18, we have taken from Recueil de Planches sur les Sciences et 

 les Arts. Paris, 1765. In Fig. 17 will be seen 



1. A pair of plain cylindrical rolls, C D, placed the one above 

 the other, each receiving motion, independent of the other, from a 

 water-wheel, there being one on each side of the mill, whose shafts 

 are seen at E and O. These rolls could be adjusted so that the 

 distance between their adjacent surfaces might be varied within 

 certain limits. These rolls equalized the thickness of the rough 

 forged bar and prepared it for the next operation. 



2. The " slitting-mill " proper, seen between the letters N and 



