20 BTTLLETIX 883, U. S. DEPAETVLEXT OF AGEICEXTUEE. 
in the results of this study. The specific gravity was high in most 
of the 1915 samples, but this was not reflected in the chemical charac- 
ters noted or in the drying properties of these oils that year. All 
three of the other characters were, in fact, lower in 1915. 
The figures for the index of refraction are quite similar in 1914 
and 1915 and lower in 1916. These, in turn, are negatively rather 
than positively correlated with the chemical and drying properties 
of the oil. 
CHEMICAL PROPERTIES OF THE OIL. 
The acid values of the oils in 1915, as shown in Table VI, were 
abnormally low. indicating that hydrolysis or oxidation and a con- 
sequent liberation of free fatty acids had taken place. This con- 
forms with the facts, for at the time of harvest cool, cloudy "weather 
continued for more than a month. The varieties ripened slowly. 
The straw remained green. Even after the flax had been in the 
shock for more than the ordinary length of time, thrashing was 
discontinued because of the failure of the seed to dry out sufficiently 
to make storing safe. 
It is interesting to note in this connection that the high-producing 
true seed-flax types were at a disadvantage hi this respect in 1915. 
All of the late-maturing varieties had materially lower acid values 
in that year than the earlier types. C. I. Xo. 3. which has a more 
definite blooming period than the others, was not so adversely af- 
fected. This, however, apparently had little effect upon the yield 
of either the seed or the oil. 
The saponification values of the oils in 1915 show a more or less 
positive correlation with the acid values hi that year, as was to be 
expected. Here again C. I. Xo. 3 appears to advantage. 
More definite and consistent differences between varieties are 
apparent hi the iodin values given hi Table VI. These, hi turn, 
are more significantly correlated with drying properties. Even 
here, there are several cases hi which numerous individual samples 
showed a low iodin value, but dried in a remarkably short period. 
C. I. Xos. 19. 16, 15. and 4 in 1914 and C. I. Xo. 5 in 1916 are clear 
examples. Taking the three-year average, however, it is evident that 
Reserve (C. I. Xo. 19) produces an oil with lower iodin value and 
slower drying properties than C. I. Xo. 2 or Xo. 3, which in point of 
seed production are equally good. Xorth Dakota Resistant Xo. 52, 
another promising seed-flax type, also produces a rapid-drying oil. 
C. I. Xo. 2 is the only seed-flax variety which hi the 3-year average 
dries in as short a period as the short-fiber varieties, C. I. Xos. 13 
and 12. C. I. Xos. 3 and 8. however, give higher iodin values than 
these short-fiber types in this average. 
