Mix well the sample, which should contain no lumps. If foreign matter is
present grind the sample to pass a 100–mesh sieve.
Place 20 grams of granulated cane sugar and 1 gram of the sample in a
250 cc. glass-stoppered bottle, tightly stopped, and mix the mass by
rolling. Do not shake hard as much of the lime could thus be lost as
dust. Then add 187.4 cc. of distilled water freshly boiled to expel
carbon dioxide. This makes 200 cc. of sugar solution. The lime is mixed
dry with the sugar and the water added later to keep the lime from
lumping. After shaking the sugar solution one hour titrate 50 cc. of it
with N/2 hydrochloric acid in presence of methyl orange indicator. The
acid used is equivalent to the carbonate and hydroxide in 0.25 gram of
the sample.
Filter the remainder of the sugar solution, discarding the first 25 cc.
of filtrate. Titrate 50 cc. of the filtrate with N/2 hydrochloric acid
in presence of methyl orange indicator. The acid used is equivalent to
the hydroxide in 0.25 gram of the sample.
If a 1 gram sample is used the percentage of calcium oxide (CaO) is
equal to 5.6 times the number of cubic centimeters of hydrochloric acid
used in the second titration; and the percentage of calcium carbonate
(CaCO_{3}) equivalent to the carbonate present is equal to 10 times the
difference in cubic centimeters between the results of the two
titrations.