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118   Life and Letters of Francis Galton

It may be difficult to get adequate appreciation of women's noteworthiness, but it is still n}ore difficult to measure heredity in ability, unless we have some direct measure of whether ability can be transmitted through the mother with strength equal to that of transmission through the father. We know whether the father was or was not noteworthy, but if we have no measure of the ability of the mother, we cannot determine whether an able maternal stock transmits its ability equally through an able and through a mediocre woman member. Further Galton does not discuss the sons of Fellows as many might not have reached maturity ; 467 persons were addressed, 207 of these sent serviceable replies, of which only 65 are treated in Schuster's list of noteworthy families of F.R.S.'s (pp. 1-79). Galton's data are numerically based on the 207 cases. He states that the real crux of the problem lies in what the remaining 260 were like. Abstention might be due to dislike of publicity, to inertia, or to pure ignorance; such causes would hardly affect the randomness of the sample, but if the 260 did not reply because they had no noteworthy kinsfolk this would influence the sample, and badly influence it. The two extremes are that (a) we suppose the 260 to share the richness of the 207 in noteworthy kinsfolk, (b) we consider that the 260 had no noteworthy kinsfolk. Galton says he cannot guess which of these hypotheses is the more remote from the truth, but considers that actuality cannot be very far removed from their mean value. I cannot find, however, that this is what Galton has really used. For example the F.R.S.'s had 81 noteworthy fathers. The percentage of noteworthy fathers on the first hypothesis is 81 x 2 0 = 39.13 and on the second hypothesis is 81 xAQ=17.34; thus the mean of the two is 28.24. Galton, however,, does not take the mean of the two hypotheses, but of the numbers 207 and 467,

and gets 337; then he finds 125- 00_=24.04, and this is the percentage he

actually uses. Taking 1 man in 100 as noteworthy-a somewhat arbitrary assumption-be states (p. xl) that F.R.S.'s have 24 times as many noteworthy fathers as the generality of men. Before we pass to Galton's final table we may cite one or two points he makes which are of distinct interest and importance for similar investigations. In Chapter IX he gives the result of marking individual degrees of noteworthiness; he made three categories and gave to them in degree of noteworthiness marks 3, 2, 1. He then reduced the total of marks for each degree of kinship (657) to the total number of cases of noteworthiness (329). As a first appreciation the two results differed very little ; thus (p. xxxvii)

Comparison of Results with and without Marks in 65 Families.

 
 

First

Degree

Second

Degree

Third

Degree

First

Cousins

Total

Number of marks assigned   ...

225

208

102

122

657

Marks reduced by factor 329   ...

113

104

51

61

329

Number of Cases of Noteworthiness

110

112

46

61

329

The reason for this approximate concordance lies in the distribution of triple, double and single marks being much the same in, the different


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