Potato Investigations 
27 
sidered as culls. In the experiment of 1918, which was on a field 
basis, the grading was done with a sorter having a 1%-iiich screen. 
With the Rural New Yorker variety this size of screen separates 
the tubers at approximately the three-ounce size. No tubers less 
than inch in diameter were included. 
Since the results will be published in detail in the complete report 
of the size of seed experiments, only parts of the summarized data 
which bring out some of the most prominent features will be in- 
cluded in this report. 
EXPERIMENTS OF 1915 
Because of the small amount of seed available, the experiment 
‘of this season was on a comparatively small scale. -The number of 
' hills planted was as follows : One-ounce whole, 120 hills ; three-ounce 
whole, 120 hills ; three-ounce halved, 240 hills ; four-ounce whole and 
halved, 60 hills each. The series was planted without duplication. The 
variety used was the Irish Cobbler. The calculated yields per acre 
fare based on the hills present at the time of digging, no allowance 
being made for missing hills. The results, which are given in the 
4th, 7th, 10th and 14th columns of Table 12, show that the number 
and weight of tubers per hill before sorting, which includes both 
marketable and culls, very consistently increased as the size of 
the seed piece increased. This was true for both the whole seed 
and the seed cut in halves. The marketable tubers and the calculated 
yields per acre also showed increases in the same direction with the 
exception of the six-ounce seed cut in halves which produced a 
slightly lower yield than the four-ounce halved. The difference, 
however, is so small as to be considered within the limits of error. 
EXPERIMENTS OF 1916-1917 
Since identical plans were followed in carrying out the experi- 
ments of these two years the results will be discussed together. 
The entire series was planted in duplicate each year with ninety 
^ hills of each lot in each series. The variety used in these experi- 
ments was the Rural New Yorker. Since the seed was planted by 
hand in an open furrow the soil dried out somewhat during the 
process of planting so that the soil which was directly in contact 
with the seed pieces did not contain as much moisture as is usually 
the case where the planting is done with a machine. Furthermore 
there was considerable drying out of the soil with which the tubers 
were covered during the hot, dry period which followed planting. 
These conditions made the test a severe one and undoubtedly served 
