Various devices are used in separating seed, the operation of 

 which does not involve a great amount of labor. These consist of 

 blowing and sifting, separation by water, chemical solutions, etc. 

 An account of results obtained by the use of chemical solutions, or 

 the specific gravity method, is given by V. A. Clark.* By this 

 method the relative specific gravity of seed can be obtained and the 

 heavier seeds selected. In the water method of separation the seeds 

 are placed in a quantity of water, shaken thoroughly, and allowed to 

 stand for a few moments. The seeds which do not sink (the light 

 ones) are removed ; while those which sink (the heavy ones) are 

 reserved for planting. 



Another method of selection is based upon the difference in the 

 volume weight of the seeds. No separation of seeds is involved, 

 those seeds being selected which give the greatest weight per given 

 volume, and the method consists in simply choosing the heaviest 

 from several samples on a basis of volume weight. 



The separation of seed by sieves is one of the simplest, easiest 

 and most practical methods employed, and is applicable to a large 

 number of varieties. Various kinds of sieves can be purchased with 

 perforations corresponding to either millimeters or inches, and of 

 round, oval, oblong or slot form. For general purposes we prefer 

 sieves having circular perforations. Perforated metal is manufac- 

 tured by various firms, and the size of the perforations varies greatly, 

 some of them apparently not corresponding to any standard unit of 

 measurement. However, it is not a difficult matter to select perfor- 

 ated metal with perforations closely approximating certain sizes, and 

 sieves are easily made by soldering strips of this material to the bot- 

 tom of any metal vessel of suitable size or by fastening them to 

 wooden frames. A large variety of perforated metal, quite accur- 

 ately gauged in fractions of an inch, can be obtained from the Har- 

 rington and King Perforating Co., 114 Liberty St., New York, and a 

 variety of sizes can usually be obtained from any tinsmith. 



Small, light seeds are best separated by the air method, and various 

 devices are used for this purpose. Some of the different types 

 of winnowing machines, used for cleaning the chaff from seed, may 

 be employed, and a form manufactured in Germany, has been 

 exclusively employed by us for separating onion seed, with very 



• N. Y. (GenevaJ Exp. Sta. Bui. 256, October, 1904. 



