56 



FRUITS AND FRUIT PRODUCTS. 



together, while in the presence of glucose the calculated polarization 

 to the left on the sugar scale is larger than the actual reading, the 

 difference depending on the amount of glucose present. The difference 

 between the calculated reading and the actual reading is marked plus 

 (H-) when the former is the greater and minus ( ) when the actual 

 reading is greater than that calculated. If all the sugar in the fruits 

 were present as invert and cane sugar it would be possible to make 

 quite exact calculations, but, as has been shown in Tables 14 and 16, 

 there is often a small excess of either levulose or dextrose. This 

 is not sufficiently marked, however, to make any serious difference, 

 especially as in nearly all the fruits examined the levulose is in excess, 

 which lessens the difference mentioned above. A small difference of 

 one or two degrees either one way or the other should be disregarded, 

 as it may be caused by the slight excess of levulose or dextrose in the 

 fruit. The following table illustrates this point very plainly: 



TABLE 19. 

 POLARIZATION OF JAMS NOT CONTAINTNG GLUCOSE. 



POLARIZATION OF JAMS CONTAINING GLUCOSE. 



