Divisions on the oil scale are sub divided by Micro meter screw errors due to temperature changes in sugar solutionscan be eliminated by temperature correction device provided. Purity and cost of production are imported considerations in the manufacturing of food products. Both thses can be dealt with by use of this instrument, because an accurate measurement of the index of refraction gives reliable check on the quality of production. It is an indispensable tool for use of all industries using sugar, oil fats arid many other similar substance.