EXPERIMENTS WITH FLAX ON BREAKING. 17 
results obtained in 1915. Similar results follow when flax is sown 
late and the growing period extends into a cool, wet fall. Then dan- 
ger of frost is threatened also. As a result of the cool season in 1915 
the 3-year average growing period is longer than ordinarily would 
be expected. 
Little difference in height of straw is noted. The averages for 
C. I. Nos. 4 and 13 are slightly lower than for the other strains, and 
this can be regarded as a fair expression of a slight tendency to 
shorter growth in these two strains. Both have slender stems and 
compact panicles, and this type of plant usually is not as tall as the 
coarser-stemmed seed-flax types. C. I. No. 12 is of the same type, 
but in this strain there is a considerable portion of fiber-flax admix- 
ture, which is reflected in the heights recorded. 
Ordinarily the slender varieties possess a higher proportion of straw 
to grain, as shown in Table V. One might expect the reverse, but 
the restricted development of their panicles causes a limited seed pro- 
duction per plant. In humid areas, where the straw is of greater 
value, this loss in yield may be overcome to some extent by heavier 
seeding and closer spacing. 
Data on weight per bushel and weight of 1,000 seeds in the different 
years are also given in Table V. Here it is seen that the seeds of 
intermediate and short-fiber varieties weigh slightly more per bushel 
than those of the seed-flax strains, but that the weight of 1,000 seeds 
of these types is much less than for the seed-flax samples. Comparing 
these results with those of the oil percentages in Table IV, it is appar- 
ent that there is a positive correlation between size of seed and oil 
percentages in these varieties and that the seed-flax strains are 
superior to the short-fiber strains in both of these characters. 
ANALYTICAL RESULTS. 
The true value of a flax variety can not be determined solely by 
its productiveness or resistance to disease. Flax is an oil-producing 
plant, and the relative values of different varieties must be based not 
only on agronomic characters but on physical and chemical deter- 
minations of the quantity, quality, and character of the oils pro- 
duced by each. Such studies have been made in connection with 
a comprehensive series of tests of all the varieties in the plat experi- 
ments herein discussed, and the data obtained are shown in Table VI. 
Rabak, 1 in his first paper dealing with one phase of these studies, 
gives a brief discussion of the properties studied and the methods 
employed. The following is a quotation from his paper: 
The present investigation was undertaken in order to compare the oils from the 
various flax samples. . . . The comparison in question should determine tenta- 
tively those varieties producing seeds with the highest yield of oil as well as oil of 
i Rabak, Frank. Influence on linseed oil of the geographical source and variety of flax. U. S. Dept* 
Agr. Bui. 655, 16 p. 1918. 
