502 Life and Letters of Francis Galton 



which he considers to be A. Then each of the selected group is marked with an A,, of so minute 

 a size as to he readily overlooked. A second examiner, No. 2, who overlooks the Aj marks, 

 proceeds in the same way, and each of his selected set is scratched with an A.,. Subsequent 

 investigation shows that: 



I. a, of the balls marked A 1 are truly A. 

 II. a., of the balls marked A„ are truly A, 

 III. a 3 of the balls marked A l and A,, are truly A. 



(Question. What is the trustworthiness, when measured on a scale of equal parts, of the 

 three estimates defined by I, II and III 1 ? 



Mum. The scale of trustworthiness is bounded, below at a zero point, of no trustworthiness 



at all, when a = l^i , and, above, where precision is absolute, when a = a. 



F. Galton. 



42, Rutland Gate, S.W. May 20, 1897. 



My deak Professor Karl Pearson, You were not, as I heard, at the Royal Society Soiree 

 last night, where I had hoped to have thanked you sincerely for the book and for the exceed- 

 ingly kind writing on the fly-leaf. It is one of the great pleasures left me, to know, now that 

 I grow older and stupider, that anything I may have done has proved serviceable to others 

 who, to misquote Tennyson, can "step from my dead self to higher things." 



I was absent from London all the day-part of yesterday and have only very cursorily as yet 

 looked through the book, but have seen enough to astonish me at its wide range and serious 

 reasonings and at its substantial unity among apparent diversity. You must indeed have had 

 difficulty in assigning a title to it. What an awful time to live in the 14th century must have 

 been to most persons, with its plagues and endemic manias of flagellations, tarantellas and the 

 like, and savage wars. No wonder that dances of death were popular. I look forward greatly 

 to reading the two volumes properly. Very sincerely yours, Francis Galton. 



Grand Hotel, Royat. August 13, 1897. 5 a.m. 



Dearest Emma, It is ill news that I have to send. You heard that Louisa* had been ill 

 since last Sunday, when she packed up in good spirits and with much interest for a tour among 

 the Dauphine mountains, beginning with the Grande Chartreuse. But it was not to be. She 

 was seized with a severe attack of diarrhoea and vomiting during the night, a repetition of what 

 she, I and Mme de Falbe had all had in a lesser degree. Still Dr Petit thought little of it on 

 Monday morning, even on Tuesday morning he was not anxious, but she grew steadily worse. 

 The bile thrown out was exceedingly disordered and I think its presence throughout the body 

 poisoned her. She had of course discomfort at times, but was on the whole drowsy. Yesterday 

 she was evidently sinking. I had a nurse to sit up through the night, who awoke me at 2 J a.m. 

 when dear Louie was dying. She passed away so imperceptibly that I could not tell when, within 

 several minutes. Dying is often easy! I believe French formalities require very early burial, 

 probably to-morrow, but I know nothing now. When the people are up and moving I shall hear 

 all about necessary legal formalities, which may take time. This is written to catch the morning 

 post to England. You shall of course hear again very soon. I cannot yet realise my loss. The 

 sense of it will come only too distressfully soon, when I reach my desolate home. Please tell 

 the brothers and sisters. I am too tired to write much, having had long nursing hours. Mme 

 de Falbe is our one friend here, but she was in bed yesterday and to-day with a slight attack of 

 the same malady. Her maid has been very helpful. The landlady is all kindness. The nurse 

 (a religieuse) did her best, and so did the chambermaid, they and another woman got up in the 

 night to do the sad and necessary offices. Dear Louisa, she lies looking peaceful but worn, in 

 the next room to where I am writing, with a door between. I have much to be thankful for in 

 having had her society and love for so long. I know how you loved her and will sympathise 

 with me. God bless you. Ever affectionately, Francis Galton. 



* Mrs Francis Galton, nee Butler. 



