THE 



PHILOSOPHICAL MAGAZINE 

 AND JOURNAL. 



3P' DECEMBER 1822. 



LXXXII. On the Origin of the Blast Furnace. By 



David Mushet, Esq.* • 



J.T is a matter of considerable regret, to those interested in the 

 rise and progress of our national metallurgy, that the compara- 

 tive I'ecent invention of the blast furnace should already be 

 involved m so much doubt and obscurity; and that we should 

 be unable to assign to it " a local habitation and a name." 



In the writings of the Saxon Agricola, published in the j'ear 

 15j6, there is no mention made of the blast furnace as known 

 to us in after ages, as the means of making and procuring that 

 strong but fusible state of iron now so universally used in 

 every mechanical art and contrivance. Agricola describes 

 the blast bloomery and the usual processes for obtaining mal- 

 leable iron, but no where does he describe a process by which 

 cast iron was obtained and applied to foundry purposes. He 

 gives the detail, however, of a curious process for making steel, 

 which renders it probable that the more fusible species of 

 cast iron was not unknown in that day, though not used for 

 the purpose of castings. 



Pieces of the most tiisible iron were introduced into a large 

 crucible, in the hearth of the iron furnace, along with a mix- 

 ture of flux and cliarcoal ; the action of the bellows was di- 

 rected so as to produce fusion ; when this was ascertained, four 

 pieces of bar iron, about SOlbs. each, were inserted in the 

 fluid, where they remained For five or six hours, till they had 

 nearly absorbed the melted iron. The masses of malleable 

 iron, being thus penetrated, enlarged in size and became soft 

 and pasty. The furnace-man then made a trial of one of the 

 bars, placing it under a large or forge hammer. The cake while 

 yet hot was plunged into cold water, and the fracture exa- 

 mined, to ascertain whether it had been all converted into 

 steel : if this was not the case, a fresh fusion became necessary; 

 and the im])erfect steel was again inserted for a length of time 

 sufficient lor its perfect conversion. 



Whether this fusible mixture was in the first instance gray 



* Cortimiinicatctl by the Author. 

 Vol. GO. No. 2fiG. />r. 1822. ' .'5 E cast 



