Biography of Johann Nepomuk von Fuchs. 227° 
Pa ist in the application of an invaluable means of rendering it sol- 
uble, and setting free its alkaline substances so important, nay, 
80 indispensable to his crops.” + Se 
Fuchs rendered an important service to mineralogy when in 
1831 he made public his method for the quantitative separation 
of the protoxyd and peroxyd of iron: His method consists in 
the use of carbonate of lime or baryta, which precipitates the 
; eroxyd but not the protexyd, from hydrochloric acid so ution. 
his process has been found further applicable to the separation 
of peroxyd of iron from protoxyd of manganese, of alumina 
tom magnesia, and for precipitating other analogous oxyds, 
Instead of carbonate of lime or of baryta, the carbonates of 
. _ Magnesia, copper, zinc, and manganese may be used, and thus 
the separations effected in sulphuric acid solution. This method 
also serves for precipitating phosphoric and arsenic acids with 
peroxyd of iron, so that these acids may be separated and deter- 
| mined in this way. In presence of these acids then, this method 
= = 
is useless for the determination of iron. Knowing this, Fuchs 
Sought another “process on occasion of the analysis of a phos- 
phate of iron fram Bodenmais, which he named Melanchlor. He 
Was thereby led to the discovery of the valuable method which 
18 founded upon the fact that hydrochloric acid does not dissolve 
Metallic copper in exclusion of air, but that it is dissolved in an 
a acid solution of perchlorid of iron. -Protoxyd of iron may also 
| be determined if it be peroxydized. The quantity of copper in 
4 solution, may be estimated also by the same method; the chlo- 
Mid of that metal is converted into subchlorid by contact with 
Strips of metallic copper, the loss of weight of the latter is equal 
the copper originally in the solution, Fikentscher has applied 
eee Fuchs’ Theory of the Earth (1837) the 
i us spoken of—“ this cha 
gelatinizing of fused epidote, garnet, 
&c. with acids; is th onk lained by the su 
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