40'4 Experiments on the immediate 



metres (or 45 feet), the excefs in the width of which is 

 clofed by a trap e moving on hinges when the furnace is' 

 at work. We had previoufly put into a Heffian crucible 15 

 centimetres (about 51 inches) in height, and 8 in diameter, 

 367 grammes (6914 grains) of fmall iron nails, and 245 

 grammes (4616 grains) of a. mixture of carbonat of lime and 

 burnt clay. This crucible was placed on its ftand in the 

 middle of the furnace. 



At one of the corners of the bottom was placed a fmall 

 crucible of kaolin with its cover, and containing two of 

 Wedgewood's pyrtfrnetrical pieces, taken from two different 

 boxes. We readily forefaw that in this pofition they would 

 not receive the fame degree of heat as the crucible placed in the 

 centre ; but it was a mode of eftimation not to be neglected. 

 The fire was kindled about half an hour after ten, and 

 urged at firft very (lowly. At one o'clock we judged the 

 fufion to be complete, took away the vitreous part, and 

 poured the matter into the ingot-mould. A part of the 

 matter remained fixed in the crucible, beeaufe too much 

 time was employed in removing the laft portions of the glafs, 

 and beeaufe perhaps a quarter of an hour more heat would 

 have been necefiary ', but the moulded portion, by its form 

 and grain, left no doubt of proper fuficn, and of its perfect 

 converfion into fteel. The pyrometric pieces, placed at the 

 corner of the furnace, gave one 136 degrees, and the other 

 140; from which it may be inferred, that" the matter in the 

 large crucible was expofed to a heat of about 150 degrees. 



" Caft fteel," fays Perret in his Memoir which obtained 

 the prize from the Society of Arts at Geneva, " is judged! 

 by moii ninths intractable ; but it is frill pofiible to over- 

 come it by attention and addrefs." That of C. Clouet re- 

 quires the fame precautions, which depend on its peculiar 

 nature; and it affords a proof that it may be forged, and that 

 in this ftate, even though its grain be not rendered liner by- 

 tempering, it will bear a companion with the Englifti caft 

 fteel. We fubjecled alio to trial, by forging, a fmall piece 



obtained 



