New YorK AGRICULTURAL EXPERIMENT STATION. 343 
The pycnometer method as commonly applied carries the deter- 
mination to four places of decimals; but this is an unneces- 
sary refinement of operation, since separates differing by only 
one-hundredth of unity commonly show very little if any differ- 
ence in germination and in vigor of seedlings except at or near 
critical points, as 1.18 for naked leguminous seeds, below which 
points germination does not take place. 
THE METHOD OF A SERIES OF SEPARATES. 
Taking into consideration the inadequacy of the method of 
samples and considering the fact that seeds differ much in com- 
position and other characters according to the conditions under 
which they are grown, and further, that seeds borne on the 
same mother plant also differ, it is surprising that greater efforts 
have not been made to separate these seeds according to their 
cultural properties. The somewhat primitive separation of a lot 
of seed into two or three arbitrarily determined separates has 
already shown that very considerable differences in cultural 
properties do exist. By making these separates at equal inter- 
vals of specific gravity and sufficiently near together, it should 
be practicable to determine the range within which seeds of 
different cultural qualities occur, so far as such are in direct 
correlation with specific gravity. By so doing, prescriptions for 
the selection of seed according to specific gravity would be made 
on the basis of an unchanging standard. Heretofore the method 
used has given variable results as regards quality of seeds, 
since a stated fraction, as one-half, of a variable quantity—the 
specific gravity of seeds grown under different conditions—was 
taken. 
The present writer has put this idea into effect! by using a 
series of salt solutions differing each from the next by one one- 
hundredth of unity in specific gravity. Seeds passed through 
such a series of solutions are grouped into a series of separates 
having different ranges with which various properties of great 
economic importance are found to be somewhat definitely asso- 
ciated. © 
As will appear later, this method of series takes into con- 
sideration the very unlike conditions under which seeds are grown, 
so far as these differences find expression in the specific gravities 
