VIII] 



FOODS AND FEEDING STUFFS 



37 



Table 2.— Herzfeld'S Table. 



For the determination of invert sugar in materials containing 1.5%, or less, of invert 

 sugar and 98.5%, or more, of sucrose. 



Method II. 

 (For materials containing 1.5% or more of invert sugar and 98.5% or less of sucrose.) 



38 



REAGENTS. 



Same as described under 24. 



39 DETERMINATION. 



Prepare a solution of the material to be examined in such a manner that it con- 

 tains 20 grams in 100 cc. after clarification and removal of the excess of lead. Pre- 

 pare a series of solutions in large test tubes by adding 1, 2, 3, 4, and 5 cc. of this 

 solution to each tube successively. Add5cc. of the reagent to each, heat to boiling, 

 boil 2 minutes, and filter. Note the volume of sugar solution which gives the fil- 

 trate lightest in tint, but still distinctly blue. Place 20 times this vo ume of the 

 sugar solution in a 100 cc. flask, dilute to the mark, and mix well. Use 50 cc. of the 

 solution for the determination, which is conducted as described under 36. For the 

 calculation of the result use the following formulas and table of factors of Meissl 

 and Hiller: 



Let Cu = the weight of copper obtained; 

 P = the polarization of the sample; 

 W = the weight of the sample in the 50 cc. of the solution used for the 



determination; 

 F = the factor obtained from the table for the conversion of copper to 

 invert sugar; 



Cu 

 Then — =Z, approximate weight of invert sugar; 



Z X 



100 



= Y, approximate per cent of invert sugar; 



