DISOXIDATION OP IRON BY HIDROGEN GAS. §75 



acid oould act on them with facility. Having evaporated The iron of 

 to dryness, water was added, and a little muriatic acid, to jysfd ^ *°*" 

 fake up the oxide of iron separated by drying. A whitish 

 granular precipitate was obtained; which, collected on a 

 filter, washed and calcined, became very white, and weigh- 

 ed 0*36 of a gram. [^5 56 grs.] This was silex. 



The solution, of a fine orange yellow colour, was sa« 

 turated by ammonia; only taking care to leave a slight ex- 

 cess of acid, to hold in solution all the earths, that might 

 have fallen down with the oxide of iron. This oxide was 

 collected on a filter ; and the liquor assayed by carbonate 

 and oxalate of ammonia to detect the presence of alumine 

 and lime. No precipitate being thrown down, the liquor 

 Tvas evaporated to dryness ; and the muriates, oxalates, and 

 carbonates of ammonia and magnesia (for, if there were 

 any earth present, it could only be magnesia) were after- 

 ward calcined. The ammoniacal salts were volatilized; and 

 a substance was left (it was an oxalate), which, having 

 been again calcined on a porcelain test, became white, and 

 weighed 0*31 of a gr. [4-79 grs.] It was magnesia. 



As the oxide of iron remaining on the filter might still 

 contain other metals and earths, it was treated by acetic 

 acid, and heated to dryness. Water was then added, and 

 it was heated to dryness again. Lastly, after having added 

 more water, cleaned the capsule, and heated a little; the 

 solution was filtered, evaporated to dryness, and the re- 

 «iduum calcined on a porcelain test. The whole was vola-* 

 tilized, except a blackish, alkaline substance, incapable of 

 being weighed, which was presumed to be lime (proceeding 

 from the filtres) contaminated by the carbon of the decom- 

 posed acetic acid. 



The iron left on the filtre was treated with muriatic acid, 

 because it was suspected to contain silex ; for the nitro- 

 muriatic acid might have dissolved a portion of this earth 

 in its state of disintegration, and the ammonia would have 

 precipitated the silex with the iron. This in fact was the 

 case: for, after having filtered the solution of iron, there 

 was a residuum, which, when washed and calcined, be- 

 came very white, and weighed 0*2 of a gram. [3*09 grs.] ; 

 apd this was sHqx. 



The 



