58 HEREDITY IN RELATION TO EUGENICS 



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Fig. 25. — Pedigree illustrating inheritance of special ability in the Fair- 

 banks family of Vermont. I, James Fairbanks; I, 2, Phoebe Paddock. Her 

 two brothers, I, 3 and 4, were iron workers, II, 1, Erastus Fairbanks moved at 

 19 years to St. Johnsbury, Vermont and began to manufacture stoves, plows, 

 etc.; II, 2, Lois Grossman; II, 3, Thaddeus, a natural mechanic, invented the 

 platform scales; II, 4, Lucy Barker; II, 5, the third brother, Joseph P. Fair- 

 banks was a lawyer, with literary tastes. 



Erastus and Lois had two sons of whom the elder. III, 1, went into the 

 scale business, showed much inventive abihty and a strong taste for natural 

 history. His brother Horace, III, 3, was an excellent administrator and 

 became Governor of Vermont. Dr. Henry Fairbanks, III, 6, son of Thaddeus 

 went into the ministry, but his love of invention drew him into the iron business. 

 He combined mechanical and literary gifts. Ill, 8, was a minister and III, 9, 

 a sagacious and exact man, was secretary and treasurer of the Fairbanks Com- 

 pany. 



If both parents lack mechanical skill and come from an 

 ancestry that lacks it no offspring will have mechanical 

 ability. Even if mechanical skill is found in the ancestry 

 of one side, but not of the other, still there will be no marked 

 mechanical abihty in the children. 



If one parent has mechanical ability and the other belongs 

 to a strain that lacks it then exceptional mechanical ability 

 will be absent or uncommon. But if the parent that 

 lacks mechanical ability comes from an ancestry that pos- 

 sessed it a large proportion of the children will have such 

 ability. Also when both parents that have slight mechanical 

 ability are descended, on one side, from persons with skill, 

 such skill will reappear in approximately one child in four. 



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