The methods of manipulation used in the polarization of sugar are of
prime importance. They consist in weighing out the sugar, dissolving
it, clarifying the solution, making it up to standard volume,
filtering, filling the observation tube, regulating the illumination,
and making the polariscopic reading.
The proper conduct of these processes, in connection with the use of
accurately graduated apparatus, is the only surety against the
numerous sources of error which may be encountered. Different sugars
require different treatment in clarification, and much must
necessarily be left to the judgment and experience of the operator.
The following directions are based upon various official procedures
such as the one used in the United States custom houses, the method
prescribed by the German government, etc. They embody also the result
of recent research in regard to sources of error in polarimetric
estimation of sugar: