In the actual determination the calculations may be based on the factors above noted, but without respect to the degree of concentration. If half the quantity of dextrose noted be present its specific rotatory power is only reduced to about 52°.75, and this will make but little difference in the results. In the case of honey 13.024 grams of the sample are conveniently used in the examination, half the normal weight for the ventzke sugar scale. The error, however, due to difference in concentration is quite compensated for by the ease of clarification and manipulation. Alumina cream alone is used in the clarification, thus avoiding the danger of heating the solution to a high temperature in the presence of an excess of lead acetate. An interesting fact is observed in cooling solutions of honey to 0°. The maximum left hand rotation is not reached as soon as the temperature reaches 0° but only after it has been kept at that temperature for two or three hours. The line representing the change in rotatory power in solutions of honey between 10° and 88° is practically straight but from 10° to 0°, if measured by the readings taken without delay, it is decidedly curved; the reading being less at first than it is afterwards. After three hours the 0° becomes sensibly constant and then the whole line is nearly straight, but still with a slight deficiency in the reading at the 0°. For this reason the computations should be based on readings between 10° and 88° rather than on a number covering the whole range of temperature. Nevertheless, if the solution be kept at 10° for three hours before the final reading is taken, no error of any practical magnitude is introduced. The calculations given above, for the cane sugar scale, can also be made in an exactly similar manner for angular rotation. The angular variation produced by one gram of levulose for 1° of temperature is 0°.01256. For 88° this would become 1°.10528. Suppose the total observed angular deviation in a given case between 0° and 88° to be 10°.404, then the weight of levulose present is 10.404 ÷ 1.10528 = 9.413 grams. In the case mentioned 26.048 grams of honey were taken for the examination. The percentage of levulose present, therefore, was 9.413 × 100 ÷ 26.048 = 36.13. =241. General Formula for the Calculation of Percentage of Levulose.=—Let _K_ = deviation in divisions of the cane sugar scale or in angular rotation produced by one gram of levulose for 1° temperature. Let _T_ and _tʹ_ = temperatures at which observations are made. Let _R_ = observed deviation in rotation. Let _W_ = weight of levulose obtained. Let _L_ = per cent of levulose required. _R_ Then _L_ = --------------- ÷ _W_. _K_(_T_ - _tʹ_)