MEASUREMENT OF VARIABLE PROPERTIES 143 



Therefore the 27 sorts of seeds are reduced to 8 sorts with regard 

 to their visible properties ' — viz. 



I. The seeds A^B^C^ 2AaB^C\ zA^BbC'', 2AW^Cc. 4A^BbCc, 

 4AaB^Cc, ^AaBbC^, SAaBbCc are ABC (round, albumen yellow, 

 coat grey-brown) . The sum of the frequencies (numerical values 

 of the 9 terms, the value of each letter being |) is 27 : 64. 



II. The seeds a^B^C\ za^BbC^, 2a^BKc, ^a^BbCc are aBC 

 (wrinkled, albumen yeUow, coat grey-brown) ; frequency 9 : 64. 



III. The seeds A^b^C^ zAabK"^, zA^b^Cc, ^AabKc are AbC 

 (round, albumen green, coat grey-brown) ; frequency 9 : 64. 



IV. The seeds A^B\^, zAaB^c^, 2A^Bbc^, ^AaBbc^ are ABc 

 (round, albumen yeUow, coat white) ; frequency 9 : 64. 



V. The seeds A%H^, 2Aab^c^ are Abe (round, albumen green, 

 coat white) ; frequency 3 : 64. 



VI. The seeds a^B^c^, 2a^Bbc^ are aBc (wrinkled, albumen 

 yellow, coat white) ; frequency 3 : 64. 



VII. The seeds a^bK^, 2a^b^Cc are abC (wrinkled, albumen 

 green, coat grey-brown) ; frequency 3 : 64. 



VIII. The seeds a^bh^ are abc (wrinkled, albumen green, coat 

 white) ; frequency i : 64.^ 



The relative frequencies of the 8 sorts of seeds are thus : 

 27, 9, 9, 9, 3, 3, 3, 1. (Compare p. 139 . Compare also the pro- 

 portions, p. 130.) 



These curious relations are calculated a priori ; they have 

 been verified by MENDEL. In his third experiment, from 

 24 Fj plants 687 seeds were obtained in all. From these in 

 the following year 639 fertUe plants were raised, and there were 

 among them (according to the seeds they yielded) — 



Observed Calculated 



639^11=270 



639XTrr "" 

 639 Xttt 



90 



639XTrr= .- 



639><-irT= 90 



639Xtt= 90 



639 xA= 30 



639 x^= 30 



639 xA= 30 



639x17= 10 



1 These 8 sorts are indicated by the 8 terms the coefficient of which is i. 

 In those terms A and a cannot exist together, nor B and b, nor C and c : the 

 number of sorts of seeds is equal to the number of terms which are free from 

 products (Aa, Bb, Cc) and composed only of squares. 



' The seeds in which 3 dominants exist (Group I.) have the frequency 27 : 64. 

 Each of the groups 11., III. and IV. in which 2 dominants exist has the fre- 

 quency 9 : 64. Each of the groups V., VI. and VII. with i dominant has the 

 frequency 3 : 64. Group VIII., without any dominant, has the frequency i : 64. 

 The relative frequencies are : 



Dominants . . o i 2 3 



Frequency . . i 3^ 3^ 3' 



