238 NATURAL INHERITANCE. 



through illness." Overwork and worry will make even mild-tempered 

 men exceedingly touchy and cross. 



The accurate discernment and designation of character is almost 

 beyond the reach of any one, but, on the other hand, a rough estimate 

 and a fair description of its prominent features is easily obtainable ; 

 and it seems to me that the testimony of a member of a family 

 who has seen and observed a person in his unguarded moments 

 and under very varied circumstances for many years, is a verdict 

 deserving of much confidence. I shall have fulfilled my object in 

 writing this paper if it leaves a clear impression of the great range 

 and variety of temper among persons of both sexes in the upper 

 and middle classes of English society ; of its disregard in Marriage 

 Selection ; of the great admixture of its good and bad varieties 

 in the same family ; and of its being, nevertheless, as hereditary 

 as any other quality. Also, that although it exerts an immense 

 influence for good or ill on domestic happiness, it seems that good 

 temper has not been especially looked for, nor ill temper especially 

 shunned, as it ought to be in marriage-selection. 



E. 



THE GEOMETRIC MEAN, IN VITAL AND SOCIAL STATISTICS. 1 



My purpose is to show that an assumption which lies at the basis 

 of the well-known law of " Frequency of Error" is incorrect when 

 applied to many groups of vital and social phenomena, although that 

 law has been applied to them by statisticians with partial success. 

 Next, I will point out the correct hypothesis upon which a Law of 

 Error suitable to these cases ought to be calculated ; and subseqxiently 

 I will communicate a memoir by Mr. (now Dr.) Donald Macalister, 

 who, at my suggestion, has mathematically investigated the subject. 



The assumption to which I refer is, that errors in excess or in 

 deficiency of the truth are equally probable ; or conversely, that if two 

 fallible measurements have been made of the same object, their 



1 Reprinted, with slight revision, from the Proceedings of the Royal Society, 

 No. 198, 1879. 



