302 



MEMORIES OF MY LIFE 



descent from one generation of a people to the next, 

 showed that the generations would be identical if 

 this kind of Regression was allowed for. 1 



In 1886 I contributed two papers [90, 91] to the 

 Royal Society on Family Likeness, having by that 

 time got my methods for measuring heredity into 

 satisfactory shape. I had given much time and 

 thought to Tables of Correlations, to display the 

 frequency of cases in which the various deviations 

 say in stature, of an adult person, measured along 

 the top, were associated with the various deviations 

 of stature in his mid-parent, measured along the side. 

 (I had long used the convenient word " mid-parent" 

 to express the average of the two parents, after the 

 stature or other character of the mother had been 

 changed into its male equivalent.) But I could not see 

 my way to express the results of the complete table in 

 a single formula. At length, one morning, while wait- 

 ing at a roadside station near Ramsgate for a train, 

 and poring over the diagram in my notebook, it 

 struck me that the lines of equal frequency ran in 

 concentric ellipses. The cases were too few for 

 certainty, but my eye, being accustomed to such 

 things, satisfied me that I was approaching the 

 solution. More careful drawing strongly corroborated 

 the first impression. 



All the formulae of Conic Sections having long 

 since gone out of my head, I went on my return 

 to London to the Royal Institution to read them up. 

 Professor, now Sir James, Dewar, came in, and probably 

 noticing signs of despair in my face, asked me what 

 I was about; then said, "Why do you bother over 



1 See Pres. Address, Section H, Brit. Assoc. Aberdeen, 1885 [86]. 



