AMERICAN INDUSTRIES SINCE COLUMBUS. 743 



Fig. 56. Vertical Cross-section of an Open-hearth 

 Furnace. 



to study it in detail. In 1808 Mr. Slade built for Cooper, Hewitt 

 & Co., at Trenton, the first " open-hearth " furnace constructed in 

 America, which was put in operation in December of that year. 

 The process made slow progress for several years, and we find that 

 in 1874 there were but 

 7,000 net tons * of steel 

 made in that way in 

 the whole country ; but 

 from year to year the 

 manufacture has in- 

 creased, until in the 

 census year ending 

 June 30, 1880, there 

 was reported 84,302 

 net tons, which we find 

 augmented to 504,351 

 net tons for the cen- 

 sus year ending June 

 30, LSOO.f 



Within recent years 

 there have been sev- 

 eral efforts to produce " direct from the ore " " blooms " or " muck- 

 bar " for use instead of " wrought scrap " in the open-hearth fur- 

 nace, some of which give promise of success under favorable con- 

 ditions of location, ore, and fuel. There have also been several at- 

 tempts to make what has been very properly called " iron sponge "J 

 for use in the "open hearth." Of the details of some of these it 

 can be said that whatever was new was not good and all that was 

 good was not new. However, it is not improbable that a good way 

 of making "iron sponge" will yet be devised, and there are some 

 encouraging experiments even now in progress. In the past 

 twenty years variously contrived rotating furnaces have been 

 invented to produce "blooms," in which for the severe manual 

 labor of puddling was substituted a mechanical movement of the 

 furnace itself. Some of these contrivances have had an epheme- 

 ral success, but none have won a place among generally approved 

 apparatus. 



The Bessemer Process. 



No improvement in practical metallurgy since the time of 

 Tubal-Cain has realized such magnificent results in increasing the 

 quantity produced and diminishing the selling price of a metal 



* Swank's Annual Statistical Report of the American Iron and Steel Association for 

 1889. 



f Census Bulletin, No. 13, Production of Steel. Report of Special Agent Dr. Will- 

 iam M. Sweet to Robert P. Porter, Superintendent of Census. 



\ This is made from a rich iron ore by depriving it of its oxygen, leaving the metallic 



