162 
made in a day. It is necessary to make use of the po- 
larization method, though it does not give so exact results. 
The polarization is made in 20 mm. glass tubes. 
Then the lead is precipitated with soda. The sugar so- 
lution is then inverted with hydrocloric acid and pola- 
rized once more. When inverting and precipitating the 
lead care must be taken that the solution does not be- 
come too diluted. 
Suppose: 
P = The value of polarization before the inversion. 
J = » » » » after » » 
J—P 
From the formula 100 . — 
a value is obtained, which 
varies in the same way as the relative percentage of 
invert-sugar, in relation to the rot resistance. 
Table 5 gives a comparison of the relation between 
these two values and the rot resistance. The value of 
100 . 
J—P 
J ’ 
however, 
is not found by way of experi- 
ments; it is the calculated value (see statements in 
table 2). 
Table 5. 
The relation between rot resistance , relative percentage 
of invert-sugar and the value 100 . 
J—P 
J ' 
Variety 
Parisian 
carrot 
Guerande 
Nantes 
stock A 
St. Valery 
stock A 
Nantes 
stock B 
St. Valery 
stock B 
! % rotten roots... 
100 4 
84.6 
33,3 
26.9 
7.i 
5.o 
% relative invert 
sugar 
66.3 
53.7 
46.8 
42.4 
30.8 
29.9 
loo . 
+ 24.7 
— 18.68 
— 50.17 
— 59.8 
— 102.3 
— 105.8 
As shown in the table the same results should be 
obtained by using this method and the reduction method 
