Stir 30 lbs. of hydrate of alumina into six quarts of acetic acid, warm,
filter, and reduce to the specific gravity required.
The hydrate of alumina is prepared by dissolving 72 lbs. of alum in 100
gals. of water, and 62 lbs. soda in 100 gals. of water. The two solutions
are mixed, this precipitate is washed eight times by decantation,
collected on a filter and pressed. It must be dissolved on the filter
before it gets dry.
NITRATE OF ALUMINA.
2 lbs. nitrate of lead;
2 lbs. alum;
2 quarts water.
Dissolve and filter off the liquid from the precipitate, and dilute to
proper standard.
The reds are turned more yellow by nitrate than by acetate of alumina, and
when the former is used more acetate of lime is taken in addition.