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17200  [AssEMBLY 
From the data thus found a table may be formed, by interpolation, — 
giving the amount of sugar corresponding to each cubic centimeter of 
permanganate, but a better way is to construct a curve representing 
the reducing power of the sugar in the different solutions ; for this 
purpose a sheet of cross-section paper divided in tenths is convenient. 
Each division on the ordinates is made to represent one milligram of 
cane sugar, and those on the abscissas 0.2 c. c. of permanganate. 
Connecting the points found above we have a curve which shows the 
amount of cane sugar corresponding to any number of cubic centi- 
meters of permanganate. ‘The curve represents cane sugar, but from 
the known ratio of reduction which the other sugars (dextrose, levu- 
lose, milk sugar, etc.) have to invert-sugar, the curve for each is 
readily constructed, ninety-five parts of cane sugar being equivalent to 
one hundred parts of invert-sugar. 
The reducing powers of the several sugars, which the chemist is 
most often called upon to determine, is represented, according to Soxh- 
let, by the folowing ratio: Dextrose : invert-sugar : milk sugar = 
105:2 : 101.2 : 74, 
It follows that the curve constructed for cane sugar agrees very 
closely with that for glucose, and may be used without serious error 
in determinations of glucose in cane juices and other solutions con- 
taining only a small percentage. A correction for the slight differ- 
ence is, however, readily made when desired. 
When many analyses are to be made the time consumed in con- 
structing the curve is more than saved in the calculations, and when 
once constructed it is availabe for all subsequent determinations, if the 
solution of permanganate is made of the same strength. 
This method of standardizing the permanganate eliminates the 
errors arising from impure re-agents, and also the titration error of 
the individual, if the standardizing is done by the same person who J 
makes the analysis. : 
To enable others who may adopt this method to compare their re- “’ 
sults with those obtained here, the following table, showing the 
amount of cane sugar corresponding to each cubic centimeter of per- 
manganate used, is inserted. One cubic centimeter of the solution of é 
permanganate is equivalent to 6.9 milligrams of copper reduced to 
cuprous oxide. 

