INFLUENCE ON LINSEED OIL OF SOURCE OF FLAX, ETC. 13 
It may therefore be stated that the yield of oil at any definite 
geographical locality as indicated by the results obtained at the 
seven stations specified is dependent largely upon the precipitation 
aid evaporation at each station. 
Arranging the stations in decreasing order of their oil yields, it is 
found that the Archer, Wyo., samples show the highest average yield 
of oil for the two seasons, followed by Highmore, S. Dak., Dickinson, 
N. Dak., Newell, S. Dak., Mandan, N. Dak., Moccasin, Mont., and 
Burns, Oreg. This ranking, in contrast to the results for different 
years, does not seem to be correlated to any extent with differences 
in precipitation between stations. Annual precipitation and evapora- 
tion and the nature of the soil in affecting the retention of moisture 
assume more importance in this connection. It may be noted also 
that the station with the highest average yield of oil (Archer, Wyo.) 
is the southernmost one (latitude 41° 42'). 
The specific gravities as given in Table V, representing the average 
of all the Cereal Investigations numbers at each particular station, 
denote in a general way the density of the oils produced at a cer- 
tain geographical locality. 
The 1915 oils were almost without exception higher in specific 
gravity than during the previous year. The Dickinson, N. Dak., 
oils of 1914 and 1915 averaged the highest in specific gravity, while 
Archer, Wyo., and Burns, Oreg., followed in close order. Mandan, 
N. Dak., Newell, S. Dak., Moccasin, Mont., and Highmore, S. Dak., 
averaged considerably lower, the oils from Highmore, S. Dak., 
being conspicuously low, occupying the seventh position with respect 
to rank during both seasons. The oils from Moccasin, Mont., also 
occupied identical positions with respect to average low specific 
gravity, being sixth in order during the two years. 
Certain of the stations were noticeably constant in producing oils 
of either high or low specific gravity during the two seasons. The 
generally lower specific gravities in 1914 may, like the yields of oil, 
be attributed to climatic and soil conditions. 
The 1914 oils were higher in average acid value than the 1915 oils, 
no apparent constancy existing at any of the stations for the two 
years. The acid value, which is a measure of free acidity, fluctuates 
considerably among the several stations during each year. When 
the condition of the seed during harvest and subsequent storage is 
favorable, the liberation of freo fatty acids takes place with rapidity. 
The stations listed in the order of the decreasing acidity of their 
oils are as follows: Highmore, S. Dak., Dickinson, N. Dak., Mandan, 
N. Dak., Newell, S. Dak., Archer, Wyo., Moccasin, Mont., and 
Burns, Oreg. 
The average iodin value of the oils from the various stations shows 
a certain relationship from year to year. Thus the Mandan, N. Dak., 
samples possessed nearly identical average iodin values during 1914 
