INSEPARABLE EFFECTS 35 



But X, carried by black and chocolate, by being outside 

 the characters combining to form the set, must also be 

 carried by blue and silver-fawn. Otherwise black 

 would differ from blue in more pairs than one and from 

 silver-fawn in more than two. Similarly, the characters 

 so far known to be carried by the four colours in the 

 first experiment are : 



By being outside the characters combining to form 

 the set, Z, which is carried by black and chocolate, 

 must also be carried by agouti and cinnamon-agouti. 



Now that three pairs of factors are shown to be in 

 operation, there must be eight related groups in all, two 

 of which remain to be found. In the following scheme 

 the characters carried by the eight possible groups are 

 shown, together with the colours belonging to the six 

 which so far have been identified : 



