92 Prof. Fuchs on a Jicw Method of analysing Iron Ores. 



Exp. 3. 50 grains of gray and white cast iron from Bergen 

 were examined, and gave Q-i'SS per cent, of pure iron : the 

 impurities, on examination, were found to consist of 

 Carbon ... 3- 4-3 



Silica 1-75 



Phosphorus 0*37 

 Sulphur ... 0-12. 



5-67 



Exp. 4. 70 grains of crystallized carbonate of iron from Lo- 

 benstein, examined, gave equal to 56'9 per cent, of protoxide, 

 equivalent to 91'68 per cent, of carbonate of the protoxide; 

 the other constituents consisted of carbonate of the protoxide 

 of manganese and carbonate of lime and magnesia. 



Exp. 5. 70 grains of specular iron ore from Gleissing in the 

 Fichtelgebirge, gave upon examination a quantity equal to 

 92'30per cent, of peroxide of iron, and 7*40 per cent of silica, 

 leaving only a loss of 0*3 per cent. 



Exp. 6. Crystallized magnetic iron, containing both ])ro- 

 toxide and peroxide, was next examined. .50 grains were 

 dissolved in hydrochloric acid, to which chlorate of potash 

 was added to bring the whole of the iron to the state of per- 

 oxide. 40*7 1 grains of copper were dissolved, which is equi- 

 valent to 5Vo6 of peroxide of iron, or 102*72 per cent. An- 

 other portion of 50 grains was dissolved without the addition 

 of chlorate of potash; the copper taken up was only 27"1 grains, 

 equivalent to 34"2 grains of peroxide of iron, or 68*4 per cent.; 

 this deducted from 102'72 indicated by the first 50 grains, gives 

 34*32, corresponding to 30*88 protoxide of iron : consequently 

 this mineral gave 68*40 peroxide of iron 

 30*88 protoxide of iron 

 0*72 loss. 



100*00 



This process is applicable in many instances to the deter- 

 mination of the quantity of copper contained in ores of that 

 metal. 



The ore of copper is to be dissolved in hydrochloric acid, 

 care being taken that the whole of the copper is converted 

 into oxide or chloride; the solution is then to be boiled with 

 copper (the necessary precautions having been first duly ob- 

 served), until it assumes a pale olive-green tint, and becomes 

 colourless on being diluted with water. If no oxide of iron 

 be present, precisely the same quantity of copper will be trans- 

 lierred to the solution as was originally contained therein; the 

 quantity of copper remaining is to be subtracted from the 

 quantity of reguline copper employed in the experiment, in 



