ix.] THE AUTISTIC FACULTY. 159 



in any person might be somehow measured, and its 

 amount determined, just as .we may measure Strength, 

 the power of Discrimination of Tints, or the tenacity of 

 Memory. Let us then suppose the measurement of the 

 Artistic Faculty to be feasible and to have been often 

 performed, and that the measures of a large number 

 of persons were thrown into a Scheme. 



It is reasonable to expect that the Scheme of the 

 Artistic Faculty would be approximately Normal in 

 its proportions, like those of the various Qualities and 

 Faculties whose measures were given in Tables 2 and 3. 



It is also reasonable to expect that the same law of 

 inheritance might hold good in the Artistic E'aculty 

 that was found to hold good both in Stature and in 

 Eye colour ; in other words, that the value of Filial 

 Eegression would in this case also be -§. 



We have now to discover whether these assumptions 

 are true without any help from direct measurement. 

 The problem to be solved is a pretty one, and will 

 illustrate the method by which many problems of a 

 similar class have to be worked. 



Let the graduations of the scale by which the 

 Artistic Faculty is supposed to be measured, be such 

 that the unit of the scale shall be equal to the Q of 

 the Art-Scheme of the general population. Call the 

 unknown M of the Art-Scheme of the population, P. 

 Then, as explained in page 52, the measure of any 

 individual will be of the form P + (± D), where D 

 is the deviation from P. The first fact we have to 

 deal with is, that only 30 per cent, of the population 



