2$2 On the Component Parts of Iron-Jlones . 



This analyfis muft not, however, be taken as a ftaridard 

 whereby the quantity of iron and earth is to be judged of 

 in calcareous iron-ftones in general. The iron-ftones of this 

 clafs contain much lefs iron than argillaceous or even fili- 

 ceous iron-ftones : 28 to 32 per cent, are produces more 

 commonly met with than 37 and upwards ; the difference 

 in point of metal being made up in lime and clay. In 

 ftating the quantity of oxygen difengaged, I conceived it pro- 

 per to adduce iron-nones, though of different claffes, yet 

 containing nearly the fame weight of metal as the quantity 

 either difengaged or abforbed mull be in a dire£t ratio to 

 the exifting quantity of iron. 



III. I operated with a filiceous iron-none, weighing 

 alto - - - - 1750 grs- 



compofed of fmall pieces, and expofed for the 

 feme length of time, and to the fame degree 

 'of heat as the former claffes : the reiidue 

 weighed - - - - 1249 



Loft in volatile matter by fimptc diflillation, 



equal to 28-6 per cent. - - 501 



In its prefent ftate the fracture of this iron- 



ftone was reddilh brown, ftudded with fpiculse 

 of finning filex, flightly adhefive to the tongue, 

 and confiderably obedient to the magnet. 



I next introduced into a crucible, unratified with 

 charcoal-duft, fome pieces of the fame mafs, 

 weighing - - - 2 374g rs - 



and expofed them to a degree of heat of equal 

 intenfity with the former ; after the pieces were 

 warned, and carefully dried, they weighed 1343 



Amount of water, acid, fulphur, and oxygen 

 djffipated - - - 1031 grs-* 



Equal to - - 43 "4 parts in 100 



LolUnfimplediiiillationasabove28-6 



Oxygen taken up - - 14*8 



