136 



HATCH EXPERIMENT STATION. 



[Jan. 



obtained. In the case of such seeds as lettuce, turnip, 

 cabbage, tobacco and other small seeds this method of sepa- 

 ration is not practicable, and other methods have to be 

 resorted to. 



From early times the separation of seeds by means of 

 water has been practised to a considerable extent. In this 

 case the seed is placed in a quantity of water, well shaken 

 and let stand a few minutes, then the seeds which do not 

 sink are removed, and only those that have sunk used for 

 planting. 



The results of some of our experiments with this method 

 of separation are given in the tables following. 



Table I. — Showing the Results of Germination with Onion and Lettuce 

 Seed separated by the Water Method; 400 Seeds used in Each, or a 

 Total of 1,600. 



Seed. 



Onion, . 

 Onion, . 

 Onion, . 

 Lettuce, 



Per Cent, germinated of — 



Light. 



38.0 

 50.0 

 44.0 

 68.0 



Heavy. 



85.0 

 58.5 

 88.0 

 90.0 



Per Cent. 

 Increase of 

 Germination 



of Heavy 

 over Liglit. 



142.5 

 17.0 



100.0 

 32.3 



Table II. — Showing the Results of Seed Germination ajid Growth of 

 Onion Seedlings sejmrated by Water ; 200 Seeds iji Each Lot, or a 

 Total of 400 used. 



This method, however, is not entirely satisfactory, JK'cause 

 many of the heavier seeds are buoyed up l>y air bubbles and 

 therefore thrown away, and in our work we have noticed 

 that a few of the undersized seeds also go to the bottom. 



