[ 230 ] 



XLI. Experiments to ascertain whether there exists any 



Affinity belirixt Carlon and Clay, Lime and Silex, se- 



paraleh/ or as Compounds united ivith the Oxide of Iron 



forming Iron Ores and Iron Stones. By David Mushet, 



Esq. of' the CaUier Iron-lVorks. 



[.Continued fron-. p. 141.] 



o 



2<7, Calcareous Ironstone. 



F this class there were subjected to experiment t'.vo va- 

 rieties : one in the state of band, or regular stratum ; the 

 other in the state of calx : the former containing about 

 25 per cent, of iron, the latter 42. 



The fir^t variety of calcareous ironstone is found about 

 two inches in thickness, and is inclosed in a regular stratum 

 of shelly limestone, mentioned in last communication. The 

 fracture of this stone is smooth and dense, exhibiting a 

 oreat number of calcareous lines which describe the exterior 

 lineaments of muscle shells. It roasts to a very fine purple 

 colour, and displays every appearance of a rich ironstone. 

 The calcareous Imes, however, soon attract moisture, swell, 

 and burst the ironstone, first into masses shaped like mus- 

 cle; but soon after an entire decomposition takes place, and 

 the ore passes into the slate of a fine powder, assuming a 

 deeper sliade as it falls. 



This band or stratum is the companion of coal metals ; 

 and wlitrevcr found indicates the existence of coal with an 

 almost unerring certainty. Its envcloppe by burning forms 

 good lime, which has in some cases been deemed to make 

 excellent mortar. The two substances, though not hemo- 

 o-eneous, yet adhere so strictly together that they cannot be 

 separated distinctly till after burning. 



The extent of this measure or stratum is so general, that 

 in almost eveiv coal field it may be met with ; and there is 

 no iron-work in Scotland but the same ironstone is found 

 modified in some shape or other. 



Exp. I. 400 grains of raw ironstone was fused per se. 

 The result was a very black shining glass, in which there 

 were found no traces of metal. 



Exp. II. 400 grains of ironstone, 



13JL of carbon, or l-30th. 



There resulted from the fusion of this mixture a shining 

 black glass, porous upon the surface and round the edges. 

 Below was found a fine shaped gobule of iron, weighing 

 9 <nains : equal to 2\- per cent. 



Exp. 



