A quantitative Study of Variation, Natural and Induced, etc. 167 
The lines from separate capsules of mother plants 250~—r11, 
250—12, and 250—ı3 were all planted on the Mitchell Farm and are 
numbered 250—11U, 250—IIV, 250—11W, 250—IIX, 250 -ırY, 
250—IIZ, 250—12U, etc. 
Table 3 shows the great difference in the soil conditions that 
existed between the Plant breeding garden and the Mitchell Farm. 
Table 3. 
| P. B. Garden | Mitchell Farm 
BO on Eg or et 0.46 % 0.43% 
3,0 6 2 1G one OR OO DER 0.28% | _ 0.31% 
ee ois, Secs is! ets s ale 0.25% | 0.13% 
Ozeane Beelaiir seo tril 0 © ao 9.35% 5.56% 
SEHEN oe SCORCH OR RER 17.00% 15.00% 
WIHENTERCORECK LT ne utc ee crue onen so > 1.89 % 1.00 % 
All plants were under careful and continuous observation through- 
out the summer and notes were taken relative to marked deviation 
of particular plants from the average of the line. 
When the plants were mature all of the individuals in sixtythree 
chosen lines were measured for height of plant, width of plant, number 
of branches per plant, and number of seed pods per plant. All mea- 
surements were taken in centimeters. 
In making the arrays for the character „Number of seed pods‘, 
the seed pods were grouped in bunches of ten. For example, class 
210—230 is treated as though but three individuals were concerned; 
that is, 210, 220, and 230. The mean of the class would thus be 
taken to be 220. This arbitrary grouping was done to save time in 
working out the arrays and constants. It affects all constants some- 
what, hence this explanation. 
The constants were worked out after the method given in Daven- 
port’s „Principles of Breeding‘‘'). All computations were carried out 
three decimal places. Where the fourth decimal was 6 or larger I 
was added to the third decimal. Where the fourth decimal was 5 
or less it was dropped. 
Below are given the frequency distribution of all the plants 
measured for each of the different characters (tables 4 to 7 inclusive), 
and the constants for each „population“ (tables 8 to rr inclusive). 
1) Davenport, E. Principles of Breeding, Appendix. (Ginn and Co, Chicago and 
Boston. 1907.) 
