20 Analysis of Iron Ores, &c. 



in it a copious precipitate, which had all the characters of 

 phosphate of lime. 



To ascertain whether chrome was contained in this liquor, 

 it was first boiled to volatilize the ammonia, and a few drops 

 of nitrate of mercury were added, which was precipitated of 

 a brown yellow, owing to a little lime remaining. This 

 precipitate, however, gave a green colour to borax, which 

 proves that it contained chrome. 



The lixivium from the residuum of the solution calcined 

 with nitrate of potash then contained phosphoric acid, 

 chrome, and silex mixed with a little alumine. There was 

 likewise in it a minute portion of manganese. — The resi- 

 duum, when thus treated and lixiviated, was in the form of 

 a reddish powder, which was dissolved for the greater part 

 by muriatic acid. There remained, however, a small quan- 

 tity of grayish matter, which was silex mingled with chrome, 

 fbr it gave a very decided green colour to borax. — The mu- 

 riatic solution contained a large portion of iron. It assumed 

 the consistence of a jelly on evaporation, which proves that 

 it contained silex. it is probable that a little chrome and 

 manganese were also concealed in it. 



It appears then that this pig iron, besides carburet of 

 iron, contains phosphuret of iron, manganese, chrome, si- 

 Jex, and alumine. Next jto the iron and carbon, it appeared 

 to M. Vauquelin that the phosphorus was most abundant. 

 It is then in the residuums of the solutions of pig and bar 

 iron that we must henceforward look for phosphorus, rather 

 than in the solutions themselves, as has hitherto been done. 

 Probably the neglecting to examine these residuums with 

 sufficient attention is the reason of our remaining so ignorant 

 of the causes of the bad quality of iron. 



M. Vauquelin admits that there is likewise a small quan- 

 tity of phosphorus converted into acid, and dissolved in the 

 liquor, probably in the state of phosphate of iron, by means 

 of the sulphuric acid. It appears to him, that, when the 

 sulphuric acid is less diluted with water, a larger quantity of 

 phosphorus dissolves in the liquor. To separate this phos- 

 phate of iron, he dilutes the solution with seven or eight 



part* 



