Adjustment of the polarimeter

As the zero is altered by alteration of the angle of halfshadow, the position of the lever h, which rotates the polarizer, must be fixed before the zero point is determined. In some instruments it is possible to rotate the analyzer without rotating the graduated circle (or the vernier where the latter is movable), and it is therefore possible to adjust the zero so as to eliminate the correction for the zero point Further, it is possible by this means to adjust the zero to different parts of the graduated scale, and thus eliminate errors in graduation. 

Experiment.—Determine the Specific Rotation of Cane Sugar. 

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