METHODS OF SAMPLING. 



11 



gravity of the beet mass and diminishes on both sides toward the 

 top and $he tip. Dividing the beet as is shown in figure 2 that is, 

 cutting it into circular portions from the center to the skin the 

 following results were obtained: 



Percentage of sugar in different vertical sections of the beet. 



From these data it is seen that the zone next to the outside of the 

 beet contains the highest sugar per cent, the next inside zone being 

 nearly as high, while the outside and the central zones are lower. If 

 the beet were cut into more zones, it would be found that the high- 

 est sugar occurred in a zone about three- 

 fourths of the way from center to the outside. 



Plant physiology shows that some cells 

 contain much more sugar than others. If 

 the beet is perfect in form a section taken 

 throughout its complete length and passing 

 to the center of the beet would be repre- 

 sentative. If the beet is not of even form 

 an error is apt to creep in, as it has been 

 found that the per cent of sugar is higher 

 in the portion of the beet that is depressed 

 than in the well-expanded portions. If the 

 weights of the sections removed in samp li ng 

 could be so regulated that they bore an 

 exact ratio to the whole weight of the beet, 

 and this were constant for all, then these 

 sections would accurately represent the 

 large sample. Unfortunately this condition 

 can only be approached, as it is possible to 

 cut a beet in half or even in quarters, but 

 beyond that it is difficult to subdivide by 

 hand. The hand method is the one usu- 



ii i T i FIG. 2. Vertical sectioning of beets. 



ally employed, however, in sampling beets, 



although machines in the form of cone-shaped rasps, which remove a 

 section from the beets, are manufactured. The rasp is circular in form, 

 thicker at the center and tapering to the edge. By running a beet 

 over this fast-revolving rasp, the section is removed in the form of a 

 fine pulp, and may be caught in a basket or box placed below it. 

 When using from 20 to 50 beets the sample of ground pulp is quite 

 large, and for accurate work it must be rapidly mixed and quartered, 

 drawing one or more samples for analysis. In mixing it is necessary 



