52 



samples is found in the smaller percentage of reducing sugar in the lat- 

 ter. 



These results with the sugar-cane juices show that when single 

 polarization alone is practiced the real percentage of sucrose can be 

 approximately obtained by adding to the direct reading one-third of the 

 percentage of glucose present. 



The results also show the preponderance of laevo-gyratory impurities 

 in cane juices. 



The left-handed disturbance, however, is greater than would be ex- 

 pected from the amount of invert sugar present. 



We would, therefore, conclude that the albuminous matters present 

 are also active, or that in the reducing sugar naturally contained in the 

 juice there is a preponderance of laevulose. 



In sorghum juices I have shown in a previous publication that the 

 differences between direct and double polarization are not so great. 

 This is due to the fact that in sorghum there is a large portion of so- 

 called soluble starch and dextro-gyratory bodies. 



STUDY OF INVERSION IN THE YARYAN QUADRUPLE EFFECT. 



To determine the invertive effect of concentrating the juices in the 

 Yaryan quadruple effect pan, a series of careful analyses of entering 

 juices and issuing sirups was made. The samples were taken in the 

 following way, viz : From the feed-box of the Yaryan apparatus a 

 measured sample of the juices was taken every two minutes for thirty 

 minutes $ four minutes after taking the first sample of juice and every 

 two minutes thereafter for thirty minutes a measured sample of the 

 issuing sirup was taken. After mixing the samples of juice and sirup 

 were subjected to analysis. It will be seen that by the above method 

 the samples of juice and of sirup were strictly comparable, In each 

 case the sample for analysis was weighed out and made up to a stand- 

 ard volume in a tared flask. The analytical manipulations were con- 

 ducted with every possible precaution. 



The results of the work are given in Tables Kos. 54 and 55. 



TABLE No. 54. Test for inversion in Yaryan pan. Clarified juice. 



