438 Report oF THE DEPARTMENT OF FIELD CROPS OF THE 
given in one case by beets grown on muck soil, and in another 
case by beets that put out a second growth of leaves. 
V. COEFFICIENT OF PURITY. 
The “ coefficient of purity ” is the proportion or percentage 
which the sugar forms of the total solids in the juice. The non- 
sugar solids prevent crystallization of sugar to some extent. . 
Therefore, the larger the amount of sugar in comparison with the 
other solids, the larger will be the proportion of sugar in the beet 
that will crystallize out and be obtained in manufacture. The 
higher the coefficient of purity, the more valuable the beet for 
economical sugar production. For a more detailed explanation, 
the reader is referred to Bulletin No. 135, pp. 556-557. 
In the various beets examined in our cooperative work the co- 
efficient of purity varied from 72.5 to 87.3 and averaged 82.3. 
The lowest degree of purity accompanied the lowest content of 
sugar and was due to the same causes. 
VI. SIZE OF BEETS. 
The weight of beets analyzed and varied from 5 to 27 ounces 
and averaged 15.7 ounces. Within these limits, the increase of 
size did not apparently exercise any marked or definite influence 
upon either the percentage or purity of sugar. 
VII. THE COST OF GROWING SUGAR BEETS. 
Each farmer cooperating in the work was furnished with 
necessary blanks and was requested to keep an accurate account 
of all labor of different kinds expended upon the plats of sugar 
beets and also to state the value of the labor. In all cases ex- 
cept one this was done, the total labor cost alone without items 
being reported in this single instance. 
In considering the results presented below, the following state- 
ments should be kept in mind: 
(1) The amount, kind and cost of labor employed differed very 
widely, as reported by different experimenters. 
