of Iron hiio Cajl Steel* 40J 



We flrft employed a Macquer's furnace in one of the labora- 

 tories of the Polytechnic School. Though its ftate of de- 

 rangement did not give us reafon to hope for the whole effect 

 of the principles of its conftruttion, a pyrometric piece 

 placed in a feparate crucible indicated that the heat had been 

 carried to 151 degrees. The crucible did not appear to be 

 either broken or cracked ; yet the fufion was incomplete, 

 and even a portion of the iron remained uncovered above the 

 portion of the vitreous mafs, without it being poflible to dif- 

 cover the caufe. 



We then relblvcd to repeat the experiment at a founder's 

 furnace ; and C. Lecour, aflayer of the mint, was fo kind 

 as to permit us to operate with that in his laboratory. Our 

 fuccefs exceeded what we expected, confidering the fize of 

 the furnace. A particular defcriptioil of this operation ap- 

 peared to us the beft means of fatisfying the demand of 

 government, finee it tends to eftablifh the poffibility of a 

 manufactory of this kind on a large fcale, and to give from 

 obiervation the balls of this new art. 



We repaired to the laboratory of C. Lecour in the mint, 

 with our colleague Yauquelin, who affifted us in our experi- 

 ments. The wind furnace is conftructed of brick. The fire- 

 place a is a fquare cavity of 25 centimetres (c/23 inches) on 

 each internal face, 45 centimetres (i6-6z inches) in height, 

 terminated at the bottom by a grate b of feven fquare bars 27 

 millimetres (one inch) in thicknefs, and raifed 25 centimetres 

 (0/23 inches) above the bottom of theafh-hole. The mouth 

 has an iron cover c, with hinges inclined about 25 degrees (fee 

 Plate IX.) from a perpendicular. The tunnel dcL, by which the 

 furnace is terminated, is built of bricks alio. It commences 

 above the aperture of the cover, and firft forms a fquare, each 

 face of which internally is equal to 25 centimetres; but it be- 

 comes narrower as it afcends, fo thai each face at the extre- 

 mity is a fifth lefs. This tunnel rifes, inclined againft the 

 wall, to the height of i} decimetres (about four feet.) 

 It is there connected with a large chunuey raifed about 15 

 D d 2 metres 



