of the Devon Iroti'Worh. 331 



nace, and yet the air does not enter into the fire through the 

 bars with increafed denfity or great velocity. I therefore 

 thought it probable, that increafing the quantity of air, 

 thrown into the blaft-furnace, in a conliderable degree, al- 

 though the •velocity or denfity might be much lefs, would 

 have the effeft of increafing its heat, and operations, and 

 produce. And as, from the principles above ftated, vi'ith 

 regard to the machinery, I faw I could greatly increafe the 

 quantity of air thrown into the furnace, by enlarging the di- 

 ameter of the blow-pipe, and regulatmg the engine accord- 

 ingly, without being obliged to employ more power, I was 

 anxious to make this experiment. 



A fyftem of management, of which I did by no means 

 approve, was adopted by the other partners of the Devon 

 company foon after the works were begun to be erefted ; 

 and, in the profecution of it, they ordered their fecond fur- 

 nace to be put in blaft, without permitting thofe meafures to 

 be taken that were neceflary tp provide and maintain a fuffi- 

 cient ftock of materials ; and alfo, without allowing their 

 blowing machine to be completed, according to the original 

 defign, by the addition of its fecond boiler. As might have 

 been expefted, a trial of feveral months to carry on two fur- 

 naces, with only half the power of fteam that was neceflary, 

 and an inadequate ftock of materials, proving unfuccefsful, 

 the company, as a remedy, inftead of making up the above 

 deficiencies, ordered one of the furnaces to be blown out, 

 and ftopped altogether. This improper meafure, however, 

 afforded me the opportunity of immediately putting in prac- 

 tice the plan I have mentioned. 



When one of the furnaces was ftopped, the other conti- 

 nued to be blown by a blcw-pipe of 2^- inches diameter, and 

 the produce of the furnace, for feveral weeks thereafter, was 

 not 20 tons of iron fer week at an average. The engine at 

 this time was making about \6 ftrokes a minute, with a 

 Itroke of the air-pump, about 4 feet 8 inches long; but 

 when I altered the diameter of the blow-pipe, firft to 3, and 

 immediately after to 3 !- inches diameter, and regulated the 

 working gears of the engine, fo as to make a ftroke of 5 feet 

 3 inches long, and about 19 ftrokes in a minute, on an 

 U u 3 average. 



