Levulose may also be prepared from invert sugar, but in this case it is difficult to free it from traces of dextrose. The most successful method consists in forming a lime compound with the invert sugar and separating the lime levulosate and dextrosate by their difference in solubility. The levulose salt is much less soluble than the corresponding compound of dextrose. In the manufacture of levulose from beet molasses, the latter is dissolved in six times its weight of water and inverted with a quantity of hydrochloric acid, proportioned to the quantity of ash present in the sample. After inversion the mixture is cooled to zero and the levulose precipitated by adding fine-ground lime. The dextrose and coloring matters in these conditions are not thrown down. The precipitated lime levulosate is separated by filtration and washed with ice-cold water. The lime salt is afterwards beaten to a cream with water and decomposed by carbon dioxid. The levulose, after filtration, is concentrated to the crystallizing point.[110] =146. Estimation of Levulose.=—Levulose, when free of any admixture with other reducing sugars, may be determined by the copper method with the use of the subjoined table, prepared by Lehmann.[111] The copper solution is the same as that used for invert sugar, _viz._, 69.278 grams of pure copper sulfate in one liter. The alkali solution is prepared by dissolving 346 grams of rochelle salt and 250 grams of sodium hydroxid in water and completing the volume to one liter. _Manipulation._—Twenty-five cubic centimeters of each solution are mixed with fifty of water and boiled. To the boiling mixture twenty-five cubic centimeters of the levulose solution are added, which must not contain more than one per cent of the sugar. The boiling is then continued for fifteen minutes, and the cuprous oxid collected, washed and reduced to the metallic state in the usual way. The quantity of levulose is then determined by inspection from the table given below. Other methods of determining levulose in mixtures will be given further on. TABLE FOR THE ESTIMATION OF LEVULOSE. (A) = Milligrams of copper. (B) = Milligrams of levulose.