375 DISOXIDATION or IRON BY HIDROGEH. GAS.' 



The iron was precipitated by ammonia, which was boiled 

 on it repeatedly to remove the acid; and, after calcination 

 in the open air, 4*08 gr, [63*02 grs.] of- fine red oxide of 

 iron .were oBtained. 



Resulte. Thus the oxidulated iron of Cogne yielded 



Red oxide of iron - 4-07*^ grammes = 62-86 grains 

 Silex - - - 0-56 = 8-65 



Magnesia - - '0'31 =4-79 



Accordingly it contained 0*87 of a gr. [13*44 grs.] of earth : 

 and consequently of the 5 gr. [77*23 grs.] employed only 

 4*13 gr. [63*75 grs.] vyere oxidule. Now in the experi- 

 ment of the disoxidation the 5 gr. [77*23 grs.] were re- 

 duced to 3*69 [56-99 grs.] : 4*13 gr. [63*75 grs.] of oxidule 

 therefore contained 1*31 gr.- [20*23 grs.] of oxigen (lost in 

 the experiment;) and consequently the oxidulated iron of 

 Cogne is at '141° per cent, or 31*72 per cent. 



Results of the In like manner the oligist iron of the isle of Elba 



^^^' yie"Je<l by analpis 



Red oxide of iron - 4*4 grammes = 67*96 grains 

 Silex - - . 0*25 = 3*86. 



Thus, as. there were 0*25 of a gr. [3*86 grs.] of earth, 

 there were only 4*75 gr. [73*37 grs.] of oxide in the sub- 

 stance employed : and, as the 5 gr. [77*23 grs.] were re- 

 duced in the experiment to 3*32 gr. [51*28 grs.], they had 

 lost 1*68 gr. [25*95 grs.]; consequently there were 1*68 gr. 

 [25*95 grs.] of oxigen to 4*75 gr. [73*37 grs.] of oxide; 

 The oligist iron of the isle of Elba therefore has *||-|° per 

 cent of oxigen, or 35*37 per cent nearly. 

 ' If we may be allowed to depend on these results, we 



may conclude, that the oxidulated iron of Cogne contains 

 32 of oxigen in 100 of the oxidule; and that the oligist 

 iron of Elba contains 35 of oxigen in 100 of oxide. 



Other Results. 

 Results from It has been seen, that there were 4*13 gr. [63-75 grs.] 



the iron of ^^ oxidule in the iron of Cogne, and that this iron was 



Cogne, ° 



oxidized in the proportion of 31*72 per cent. It has ap- 

 peared too, that the 3*69 gr. [56*99 grs.] of iron of Cogne 



* Just above it is said 4*08 gram. C. 



obtained 



