Hydrometer for Soil Analysis

There will be no abrupt changes in the cross section of the hydrometer, that will hinder cleaning or drying or permit air bubble to be trapped. The graduation of hydrometer will be on the basis of liquid having a surface tension of 55 dynes/cm. The graduation lines will be at intervals of 0.0005, every alternate line will extend beyond the shortest lines; every tenth graduation will exceed that of all the intervening lines and will be numbered in full. The basis of the scale will be density (g/ml) at 27 deg C. The maximum permissible scale error on the hydrometer is plus or minus one scale division.