New YorK AGRICULTURAL EXPERIMENT STATION. et 
individual seeds the writer observed that they were of very unlike 
specific gravities. This observation suggested a study of the sub- 
ject of specific gravity as a moment of seed selection. 
This report is based on only one season’s work. The litera- 
ture of the subject is reviewed and some preliminary observa- 
tions are presented. The presentation throughout is tenative 
and subject to future verification, modification and especially 
development. It is hoped to continue this work. 
I am under obligations to the authorities of Cornell University, 
and especially to Mr. W. H. Austen, in charge of the Reference 
Library, for kind permission to use the University Library. 
HISTORICAL. 
The method of seed selection by means of salt solutions has 
long been known to gardening. Yokoi* remarks that it has been 
practiced for over 250 years in China and Japan. A simpler form 
of the method, which consists in floating off light seed in pure 
water, is by some practiced in this country at the present time, 
as for instance among growers of lettuce under glass. But the 
method appears never to have come into any considerable vogue, 
either in Europe or in America; and this despite the facts that 
striking results have repeatedly been obtained by its use and that 
several European experimenters have recommended it. 
Perhaps one reason is that several prominent investigators, in- 
cluding Nobbe, Hellriegel and Wollny, have examined it crit- 
ically and declared it to be of little or no value in agriculture. 
Yet over against the critical studies of these trained investigators 
stands a mass of experience and numerous practical tests which 
declare that the heavier seeds as separated by salt solutions do 
produce the better crops. Where there is much smoke there 
must be some fire. Perhaps the practical experimenters, who 
did not examine the subject critically, have misinterpreted their 
results; but the results stand. 
PREVIOUS INVESTIGATIONS FAVORABLE TO THE SPECIFIC GRAVITY 
METHOD. 
Some of these practical tests and recommendations may be 
cited : 
*Citations for this and other references in this report to writings on specific 
gravity of seeds referred to with the name of the author, may be found in bib- 
liography at the close of this bulletin. 
22 
