4 BULLETIN 655, U. S. DEPARTMENT OF AGRICULTURE. 
plant of the soil foods with air and water. Garner, Allard, and 
Foubert 1 have shown that climatic conditions exert a marked 
influence upon the oil content of certain seeds. Provided the content 
of oil is affected by environmental conditions it is very probable 
that the composition or the proportion of the component parts of 
the oils is likewise modified and altered. 
Pigulevskii 2 has found from an examination of numerous plants 
in respect to oil content and composition that the nature of the oil 
in a plant is influenced by climatic conditions and possibly also by 
conditions of nutrition. A large number of plants of the same 
family grown in different parts of Russia yielded oils the nature of 
which varied with climatic conditions. 
The effect of such climatic conditions as latitude, temperature, 
sunshine, and rainfall have been studied by Wiley 3 and found to 
influence the sugar content of sugar beets strongly. Likewise, 
the starch and protein content of the wheat grain have been found 
to be influenced by season and climate. 
Various localities will be found to have varying conditions of 
climate aa.d soil, the extremes and means of which act in either 
facilitating or retarding the growth of the plants and therefore affect 
favorably or unfavorably the formation of oil in the seeds. 
PLAN OF COMPARISON OF THE OILS. 
The present investigation was undertaken in order to compare 
the oils from the various flax samples grown at the several stations 
during the two successive seasons. The comparison in question 
should determine tentatively those varieties producing seeds with 
the highest yield of oil as well as oil of the best quality. Informa- 
tion of such character is of the utmost importance in connection 
with the production and improvement of this staple crop. How- 
ever, it is not only important to ascertain the high oil-yielding 
varieties of seeds, but the properties and general behavior of the 
oils are of equal importance. The physical and chemical properties 
of the oils determine their value to a large extent. In order to 
facilitate the best comparison, only those properties which admit of 
accurate measurement and which have a direct bearing upon the 
quality of the oils were considered. 
Color, specific gravity, and index of refraction are important 
physical properties in which variations can easily be detected. 
Since the color of most drying oils is an important consideration, 
but does not admit of measurement, it was necessary to describe 
1 Gamer, W. W., Allard, H. A., and Foubert, C L. Oil content of seeds as affected by the nutrition of 
the plant. In Journ. of Agr. Res., U. S. Dept. Agr., v. 3. p. 248. 1914. 
2 Pigulevskii, C. V. In Zhurn. Russk. Fiz.-Khim. Obshch., v. 47, p. 393-405, 1915; v. 48, p. 324-341, 1916. 
3 Wiley, H. W. Influence of environment on composition of plants. In Yearbook, Dept. of Agr., 
for 1901, p. 307, 310. 
