242 OBSERVATIONS ON ACETATE OP ZINC. 
stage of oxidation, or else it will seldom answer the end in 
view, and frequently fails altogether. 
The author on a recent occasion in preparing several 
pounds of this salt, employed an -article of zinc, said to be 
free from iron, but which was found to have contained a 
considerable portion of it. In resorting to the calcareous 
chloride for assistance in the difficulty, it was found that 
repeated additions of the chloride failed to separate the iron, 
the solution became amber-coloured and transparent. 
In seeking for a remedy, a trial was made by boiling the 
coloured solution with hydrated carbonate of zinc and fil- 
tering, which was found to separate the iron entirely, af- 
fording a perfectly pure and colourless solution of the ace- 
tate. The best plan of proceeding is as follows : Separate 
about one-thirtieth part of the colored liquid, add a slight 
excess of carbonate of potassa and wash the resulting car- 
bonate of zinc until freed from acetate of potassa. The 
magma of carbonate of zinc thus obtained is added to the 
boiling solution in divided portions, until, on filtering a 
little of the liquid, it is found colourless; when the whole 
should be filtered off from the colored carbonate of zinc, 
evaporated and crystallized. 
Since employing the above method, a more simple, though 
less unobjectionable application of the same principle has 
been tried, which consists in merely throwing into the 
coloured acetate a solution of carbonate of potassa ; of course 
carbonate of zinc and acetate of potassa are produced, and 
the carbonate, from being presented in its nascent state, is 
peculiarly fitted for acting on the acetate of iron. The 
small quantity of acetate of potassa in the solution remains 
in the last mother liquor. 
This method of using the hydrated carbonate of a me- 
tallic oxide to free its soluble salts from iron, has been em- 
ployed in the case of manganese ; but I am not aware of its 
having been used with this intent in the case under con- 
sideration. 
