SEPARATION OF SEED BARLEY BY GRAVITY METHOD. 5 



rate of seeding should be pro})ortionately increased. Seed treated 

 in this manner will be free from small and weak grains, and a better 

 stand and greater yield will be secm'ed from it than from ordinary 

 seed. 



This method is not to take the place of the fanning mill, but is 

 to be used in connection with it. It will remove man^' of the small 

 grai;is and weed seeds not removed by that machine. Where tiie 

 fanning mill is not available the treatment here described will be 

 found of great value. 



If it is desired to treat the seed for smu^ the sorting and treating 

 0})era(i()iis can be combined 1)v substituting "jr the water a formalin 

 solution at the rate of 1 })ound of formalin to 40 gallons of water, 

 as described in Farmers' Bulletin No. 250. 



THE GENERAL USE OF THE SPECIFIC GRAVITY METHOD. 



The separation and selection of seeds by the specific gravity test 

 has l)een practiced, according to Yokoi,'^ in China and Japan for" 

 more tluui two hundred and fifty years. Hellreigel, Rlimpler, Xobbe, 

 and numy other European investigators have carried on similar ex- 

 periments. Riimpler, '^ from the lesults secured in his experiments in 

 the separation of barley seed with solutions of sodium nitrate, advised 

 planting only the heaviest third of the seed. 



The separation of seed by the specific gravit}' method is not new in 

 tiic United States. The simple plan of placing lettuce and other vege- 

 table seeds in a dish of water and skimming off the light seeds and 

 cliaff has been practiced among the Pennsylvania Dutch and their 

 descendants for many years. Lack of knowledge of the process 

 probably accounts for the fact that it has not come into general use. 

 Dr. T.L.Lyon, of the Agricultural Experiment Station of Nebraska, <^ 

 made selections of wheat by the specific gravity method and secured 

 an increased yield from the heavier seed. Prof. H. Garman, of the 

 Kentucky Agricultural Experiment Station,'' removed weed seeds 

 from hemp seed ])y this method. Probably the most important 

 work along this line, however, was done by Prof. Y. A. Clark, of the 

 New York Agricultural Experiment Station,^ who conducted numer- 

 ous experiments with a large number of vegetable seeds, grape seeds, 

 etc. Among his conclusions the following may be cited: 



Specific gravity may be utilized as a means of separating foreign matter, or, occa- 

 sionally, foreign seeds. * *• * A quite definite correlation exists between the 



« Yokol, T. Bulletin, Imperial University, College of Agriculture (Tokyo), vol. 3, 

 no. 5, pp. 421-439. 



b Deutsche Landwirtschaftliche Presse, Berlin, 1896, p. 194. 

 c Bulletin 72, Agricultural Experiment Station of Nebraska. 

 ^ Bulletin 105, Kentucky Agricultural Experiment Station. 

 « Bulletin 256, New York Agricultural Experiment Station. 

 [Cir. Gli] 



