CANE SUGAR. 



The material under analysis is first made up to 100 cc. in the presence 

 of its precipitate, filtered, and 50 cc. of the filtrate diluted to 200 cc., 

 and the reading observed ; let it be a. The same weight of material is 

 made up to 200 cc. in the presence of its precipitate, and the reading taken; 

 let it be b ; let the volume of the precipitate be x the two readiugs to be 

 observed are now almost exactly at the same dilution ; then 2 (100 a?) =r 

 (200 x) I. 



Solving this equation x is found. 



2. Method of Sachs. 9 The precipitate obtained is collected on a filter and 

 washed until free from sugar ; it is then transferred to a graduated flask into 

 which is weighed a sugar of known polarization. This weight of sugar is 

 then made up to an apparent definite volume in the presence of the precipitate 

 and a polarimetric reading taken. The apparent increase in the polarization 

 of the sugar affords data to calculate the volume of the precipitate. 



3. Wiechmanri's Method. 9 The precipitate is collected, washed free of 

 sugar, dried and weighed. Its specific gravity is then obtained with the 

 pycnometer, benzene being the liquid used ; from its weight and density the 

 volume of the precipitate is calculated. 



4. Home's Method. 10 Home eliminates the error due to the volume of 

 the lead precipitate by making the solution of sugar product up to definite 

 volume, and clarifying by the addition of dry basic acetate of lead in 

 powdered foim, and assuming that the volu^ne of the acetic radical which goes 

 into solution is compensated by the volume of the material precipitated. This 

 method has met with considerable approval. 



The Presence of Active Bodies other than Sugar. The 



active bodies other than cane sugar present in cane products are chiefly dextrose 

 and levulose; mannose and raifinose in small quantities have also been 

 reported, and small quantities of gums are also present. The disturbing 

 influence of dextrose and levulose is removed by the Clerget method, and the 

 other bodies are generally present in such small quantities as to be negligible. 



The Effect of Lead Acetate on the Opticity of Sugar. 



The effect of lead acetate on cane sugar is small, and is given by Bates 

 and Blake 11 as under, pure sugar being tested in normal concentration 



450 



