6 SEPAEATION OF SEED BAKLEY BY GEAVITY METHOD, 



specific gravity of a seed and its germination. Seeds of low specific gravity do not 

 germinate at all. Seeds of highest specific gravity, or in the case of oil-bearing seeds 

 those of intermediate specific gravity, show the highest percentage of germination. 

 * * * To some extent a correlation appears to exist between the specific gravitj' 

 of the seed and the vigor of the resulting plant. 



SUMMARY. 



The yield to the acre of barley in the United States in 1909 was 

 1| bushels less than the ten-year average from 1900 to 1909. 



The quality of a considerable part of the crop was inferior and the 

 germinating power consequently low. 



The six-rowed barleys predominate in the United States. Owing 

 to the arrangement of the spikelets upon the rachis in this type, 

 there are twice as many smaller, twisted grains as large, plump grains. 

 It is these small, chafly grains that cause decreased stands. Fanning 

 or screening will not always remove them; the specific gravity 

 method will. 



The specific gravity method here proposed is the immersion of the 

 seed barley in a tub or barrel of water and thoroughly stirring it. 

 The greater portion of the undesirable seeds will float and can be 

 skimmed off. 



The seed can be treated for smut in the same operation by adding 

 formalin at the rate of 1 pound to 40 gallons of water. 



The specific gravity method is not new. It has been used in 

 China and Japan for two hundred and fifty years. Experiments eon- 

 tlucted in Europe and the United States in which salt solutions were 

 used in the specific gravity test demonstrate its value in seed 

 separation. 



Approved : 



James Wilson, 



Secretary of Agriculture. 



Washington, D, C, ilpril 7, 1910. 



[Cir. Gli] 



o 



