68 
IOWA ACADEMY OP SCIENCES. 
SAMPLE NO. 
Hours dried 
Per cent 
moisture. 
POL. RE 
li 
a 
p 
o 
% 
ADINGS. 
V 
o 
> 
s 
Sucrose, 
per cent 
Keducing 
sugar, per 
cent 
Acids (for- 
mic) per 
cent. 
Ash. per 
cent. 
Total, per 
cent. 
I 
27 
18.95 
-11.60 
-17.. 53 
4.46 
7.5.30 
.13 
.10 
98.94 
II 
13 
17.09 
- 4.46 
-13 63 
3.74 
77 01 
.07 
.14 
10L25 
m 
1(5 
18 18=^ 
-19.66 
-24 22 
3 36 
74.09 
.14 
95.77 
IV 
20 
16.90 
-12.80 
-19.60 
3.60 
76.10 
.30 
96.90 
*Lay in desiccator over sulphuric acid one year and six weeks, and had then lost 
18.23 per cent moisture. 
The plan of analysis was as follows: 
A normal charge for the Soliel-Ventske Polariscope (26.048 
grams) was put into 100 cc of solution, defficated with Aluminum 
cream and polariscope readings taken in a 200 mm tube; part ; 
of the solution was inverted with acid at 67® to 70® C, cooled, | 
and readings taken at the same temperature as those of the j 
normal uninverted solution. Corrections were made for acids i 
and defficator at the required times and all final figures given ' 
are for solutions of normal charge. 1 
For the determination of sucrose the double polariscope 
readings figured by Clerget’s formula were used. 
Difference bewteen Pol. readings x 100 p 
14F=4'T 1 
Cleget’s formula is an abbreviated expression from which to 1 
determine the per cent (C) of sucrose in the presence of glucose 1 
sugar. The figure 144 is the greatest range of deviation that can \ 
be produced by the inversion of a normal solution of sucrose into 
invert sugar at zero degrees C. Since, however, levulose is 
present in invert sugar and its optical activity changes as the 
temperature increases or diminishes, and it is found that the 
range of 144 divisions decreases one division for each two 
degrees rise of temperature from zero, it is necessary to sub- 
tract from the greatest range such a figure as will express the 
loss of optical activity of the levulose, due to rise of tempera- 
ature above 0® C. The formula is based upon the fact that if 
the solution in question were a normal one of cane sugar it 
would read 100 divisions in the polariscope. 
The figure thus obtained by Clerget’s formula will not be a 
true one should any other sugar than sucrose be present and 
become inverted during the inversion. In honey there is a pos- 
sibility of dextrin being present, this substance might after con- 
tinued inversion be changed into dextrose. I feel safe in 
assuming, however, that dextrin, even if present, would not 
