i6 THE POPULAR SCIENCE MONTHLY. 



tuyeres. Under this tile was an air-chamber, connected by pipes 

 with the blowing-engine. This is substantially the plan now 

 used in the Bessemer converter. The first trial of this furnace 

 was very satisfactory. The iron was well refined and decarbon- 

 ized — at least as well as by the finery fire. This fact was ad- 

 mitted by all the forgemen who examined it. The blowing was 

 usually continued from five to ten minutes, whereas the finery 

 fire required over an hour. Here was a great saving of time and 

 fuel, as well as great encouragement to work the process out to 

 perfection. I was not satisfied with making refined or run-out 

 metal ; my object was to make malleable iron. In attempting 

 this I made, in the course of the following eighteen months, a 

 variety of experiments. I built a suitable hot-blast oven ; but, 

 after a few trials, abandoned it, finding the cold blast preferable, 

 for many reasons. After many trials of this furnace I found 

 that I could make refined metal, suitable for the charcoal forge 

 fire, without any difficulty, and, when the blast was continued 

 for a longer period, the iron would occasionally be somewhat 

 malleable. At one time, on trying the iron, to my great sur- 

 prise, I found the iron would forge well, and it was pronounced 

 as good as any charcoal forge iron. I had a piece of this iron 

 forged into a bar four feet long and three eighths of an inch 

 square. I kept this bar for exhibition, and was frequently asked 

 for a small j^iece, which I readily gave, until it was reduced to a 

 length of a few inches. This piece I have still in my possession. 

 It is the first piece of malleable iron or steel ever made by the 

 pneumatic process." 



Although not giving up the idea of making malleable iron, 

 Mr. Kelly now proceeded to utilize his invention so far as it was 

 a complete success. He built a converter, five feet high and 

 eighteen inches inside diameter, with the tuyere in the side. In 

 this vessel he could refine fifteen hundred-weight of metal in 

 from five to ten minutes, effecting a great saving in time and 

 fuel. After a few days' trial, the old, troublesome " run-out " 

 fires were entirely dispensed with. " M}^ process," says Mr. Kelly, 

 in the account above quoted, " was known to every iron-maker in 

 the Cumberland River iron district as ' Kelly's air-boiling pro- 

 cess.' The reason why I did not apply for a patent for it sooner 

 than I did was that I flattered myself I would soon make it the 

 successful process I at first endeavored to achieve — namel}", a pro- 

 cess for making malleable iron and steel. In 1857 I applied for a 

 patent, as soon as I heard that other men were following the same 

 line of experiments in England ; and, although Mr. Bessemer was 

 a few days before me in obtaining a patent, I was granted an inter- 

 ference, and the case was heard by the Commissioner of Patents, 

 who decided that I was the first inventor of this process, now 



