182 An Analysis of two Mineral 
porated to half its original bulk. 5. Tincture of 
galls strikes a purple colour before the water is 
boiled; after boiling, there is a precipitate likewise, - 
but of a dull lemon-colour; after a partial evapora- 
tion, the colour approaches to whiteness. In each 
of the two last cases, the liquor gradually acquires a 
deep yellow tinge.—In these experiments, we have 
none of the ordinary signs of iron, except of the 
carbonat (11.), though its existence in the water has 
been proved beyond question (3.). 
V. MANGANESE IS DISSOLVED IN THIS 
WATER. 
As zinc is known to have a stronger affinity to 
acids than the other metals have, I hoped by its 
mean to obtain some information on the cause of 
the facts I have described. 1. I boiled, therefore, 
some of the water in a glazed vessel, in contact 
with some pieces of zinc: a small precipitate was 
formed, but enough to be collected for examination 
with the blowpipe. This was fused with borax; 
and a globule was formed of a rich red colour, pre- 
cisely that communicated by manganese.* Continu- 
ing the fusion the colour vanished; nor could I 
make it re-appear by the yellow flame of the blast: 
probably, because the manganese was mixed with 
another metal. The globule was removed to a sil- 
* For the properties of this mineral, see Scheele’s Essay 
on Manganese; or Bergman on the white Ores of Iron, 
